HK1228237B - Systems and methods to gather and analyze electroencephalographic data - Google Patents

Description

Systems and methods for collecting and analyzing electroencephalographic data

This application is a divisional application. The name of the invention of the parent application is “System and method for collecting and analyzing electroencephalogram data”, the application date is August 17, 2013, and the application number is 201310471815.3.

Technical Field

The present disclosure relates generally to neural and physiological monitoring and, more particularly, to systems and methods for collecting and analyzing electroencephalographic data.

Background Art

Electroencephalography (EEG) involves measuring and recording the electrical activity generated by thousands of simultaneous neural processes associated with different parts of the brain. EEG data is typically measured using multiple electrodes placed on the user's scalp, measuring the voltage fluctuations caused by this electrical activity within brain neurons. Subcranial EEG can measure electrical activity with high precision. Although the bone and dermis of the human head tend to attenuate the transmission of many frequencies, surface EEG also provides useful electrophysiological information.

Summary of the Invention

According to a first aspect of the present invention, a method is provided, which includes: evaluating a first attribute of a first neural signal; determining whether the first neural signal complies with a quality threshold based on the first attribute; evaluating a second attribute of a second neural signal; determining whether the second neural signal complies with the quality threshold based on the second attribute; adjusting the first neural signal to obtain a third neural signal when the first neural signal does not comply with the quality threshold; adjusting the second neural signal to obtain a fourth neural signal when the second neural signal does not comply with the quality threshold; evaluating a third attribute of the third neural signal; determining whether the third neural signal complies with the quality threshold based on the third attribute; evaluating a fourth attribute of the fourth neural signal; determining whether the fourth neural signal complies with the quality threshold based on the fourth attribute; selecting the first of the first neural signal, the second neural signal, the third neural signal or the fourth neural signal based on the corresponding compliance with the quality threshold to perform at least one of the following: for additional analysis, ignoring the second of the first neural signal, the second neural signal, the third neural signal or the fourth neural signal, or merging with the second of the first neural signal, the second neural signal, the third neural signal or the fourth neural signal.

According to a second aspect of the present invention, a system is provided, which includes: a head-mounted device for collecting a first neural signal and a second neural signal from a subject's brain; and a processor for: evaluating a first attribute of the first neural signal; determining whether the first neural signal complies with a quality threshold based on the first attribute; evaluating a second attribute of the second neural signal; determining whether the second neural signal complies with the quality threshold based on the second attribute; adjusting the first neural signal to obtain a third neural signal if the first neural signal does not comply with the quality threshold; adjusting the second neural signal to obtain a fourth neural signal if the second neural signal does not comply with the quality threshold; evaluating a third attribute of the third neural signal; determining whether the third neural signal complies with the quality threshold based on the third attribute; evaluating a fourth attribute of the fourth neural signal; determining whether the fourth neural signal complies with the quality threshold based on the fourth attribute; selecting the first of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal based on the corresponding compliance with the quality threshold to perform at least one of the following: for additional analysis, ignoring the second of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal, or merging with the second of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal.

BRIEF DESCRIPTION OF THE DRAWINGS

1 illustrates a perspective view of an example headset having multiple adjustable straps in accordance with the teachings of the present disclosure.

FIG. 2 is a right side view of the head mounted device of FIG. 1 .

FIG. 3 is a left side view of the head mounted device of FIG. 1 .

4A is a perspective view of the head-mounted device of FIG. 1 in an example orientation.

4B is a perspective view of the head-mounted device of FIG. 1 in another example orientation.

5 is a perspective view of an example adjustable strap or spine of the head-mounted device of FIG. 1 .

FIG. 6 is an enlarged view of the end of the example ridge of FIG. 5 .

FIG. 7 is a cross-sectional view of the example ridge of FIG. 5 .

8A is a circuit diagram of an example EEG system.

8B is a circuit diagram of an example EEG system with wet electrodes.

8C is a circuit diagram of an example EEG system with dry electrodes according to the teachings of the present disclosure.

9 is a schematic diagram of the top of the head illustrating example electrode and ground placement locations.

10 is an enlarged view of an example adjustable mechanism shown on the head-mounted device of FIG. 1 .

11A is a perspective view of the example electrode of FIGS. 1-7 .

11B and 11C are front views of two alternative example electrode designs.

1 ID is a perspective view of an example center electrode array plate.

12A is a block diagram of an example switching circuit.

FIG12B is a graphical representation of averaging multiple channels of data.

13A is a cross-sectional view of an example electrode in contact with a user's scalp.

13B is a cross-sectional view of an alternative example electrode in contact with a user's scalp.

FIG14 is a circuit diagram of an example electrode.

15 is a perspective view of an alternative band or ridge and an alternative electrode constructed in accordance with the teachings of the present disclosure.

FIG. 16 is an exploded view of the example electrode of FIG. 15 .

17 is an exploded view of another example snap electrode constructed in accordance with the teachings of the present disclosure.

18 is a perspective view of another example electrode constructed in accordance with the teachings of the present disclosure.

19A is a perspective view of another example electrode constructed in accordance with the teachings of the present disclosure.

19B is a cross-sectional view of the example electrode of FIG. 19A .

20 is a perspective view of an example mold for making an example ridge.

21 is a perspective view of the example ridge after fabrication in the example mold of FIG. 20 .

22A-22J are perspective views of a user's head and example areas for electrode contact.

23 is a perspective view of another example head mounted device constructed in accordance with the teachings of the present disclosure and having multiple bands with electrode heads.

24 is a bottom view of the example head mounted device and USB connection port of FIG. 23 .

25 is a perspective view of the example head mounted device of FIG. 23 on a USB base.

Figure 26 is a rear view of the example head-mounted device of Figure 23.

Figure 27 is a top-side view of the example head-mounted device of Figure 23.

Figure 28 is a right side view of the example head-mounted device of Figure 23.

Figure 29 is a bottom perspective view of the example head-mounted device of Figure 23.

Figure 30 illustrates an exploded view of example layers of an example head mounted device.

31 is an exploded view of the example circuit housing of FIG. 30 .

32A-32D are exploded views of example electrode connectors used in the example head mounted device of FIG. 23 .

33 is a side view of the example electrode connector of FIGS. 32A-32D in a partially assembled state.

34 is a perspective view of another example head mounted device constructed in accordance with the teachings of the present disclosure.

Figure 35 is a perspective view of an adjustable knob for the example head-mounted device of Figure 34.

Figure 36 is a block diagram of example circuitry from the head-mounted device of Figures 1, 23 and/or 34.

37 is a block diagram of an example manner of implementing the processor and signal selector of FIGS. 1-7 and 12 .

38 is a block diagram of an example manner of implementing the head mounted device(s) of FIGs. 1 , 23 , and/or 34 with an additional physiological sensor system.

39 is a block diagram of an example manner of implementing the processing and adjustments of FIGs. 1 , 23 , and 34 .

40 is a flow chart representing an example method of analyzing EEG data according to the teachings of the present disclosure.

41 is a flow chart illustrating an example method for improving EEG signal quality according to the teachings of the present disclosure.

42 is a flow chart illustrating an example method for performing at-home patient monitoring/treatment according to the teachings of the present disclosure.

43 is a flow chart illustrating an example method for processing a user's attention to media and desire to control a device according to the teachings of the present disclosure.

44 is a flow chart representing an example method for collecting and analyzing EEG data according to the teachings of the present disclosure.

FIG. 45 illustrates an example processor platform that may execute one or more instructions of FIGs. 40-44 to implement any or all of the example methods, systems, and/or apparatus disclosed herein.

DETAILED DESCRIPTION

Certain examples are shown in the accompanying drawings and disclosed in detail below. When describing these examples, like or identical reference numerals are used to identify the same or similar elements. The drawings are not necessarily drawn to scale, and certain features and certain views of the drawings may be shown exaggerated in scale or in an exaggerated schematic manner for the sake of clarity and/or simplicity. In addition, various examples are described throughout this specification.

Biological cells and tissues have electrical properties that can be read, providing information about the function of the cell or tissue. Various types of electrophysiological techniques have been developed to measure electrical signals from the human body. For example, electrocardiography (ECG or EKG) measures electrical activity in the heart. Electroencephalography (EEG) measures electrical activity in the brain. Electrocorticography (ECoG) measures electrical activity using electrodes placed directly on the exposed surface of the brain to record electrical activity in the cerebral cortex. Electromyography (EMG) measures electrical activity in muscles. Electrooculography (EOG) measures the resting potential of the retina, and electroretinography measures the electrical response of retinal cells. These and/or other electrophysiological signals are important in the treatment, diagnosis, and monitoring of many health conditions.

EEG data indicates the electrical activity of neurons, including neural depolarization in the brain caused by stimulation of one or more of the five senses (evoked activity) and electrical activity in the brain generated by thought processes (spontaneous activity). The sum of these electrical activities (e.g., brain waves) propagates to the surface and can be detected using EEG. Because electrical currents in the human body are caused by ion flows, biopotential electrodes, which form an electrical double layer with the human skin, are used to sense ion distribution.

EEG data can be categorized into various frequency bands. Brainwave frequencies include the delta, theta, alpha, beta, and gamma frequency ranges. Delta waves are classified as waves less than approximately 4 hertz (Hz) and are prominent during sleep. Theta waves have a frequency between approximately 3.5 Hz and approximately 7.5 Hz and are associated with memory, attention, emotion, and sensation. Theta waves are typically prominent during states of internal focus. Alpha frequencies range from approximately 7.5 Hz to approximately 13 Hz, typically peaking around 10 Hz. Alpha waves are prominent during states of relaxation. Beta waves have a frequency range between approximately 14 Hz and approximately 30 Hz. Beta waves are prominent during states of motor control, large-scale synchronization between various regions, analytical problem solving, judgment, and decision making. Gamma waves occur between approximately 30 Hz and approximately 100 Hz and are involved in binding different neuronal populations together into networks for the purpose of performing certain cognitive or motor functions, as well as attention and memory. Because the skull and dermis attenuate waves in this frequency range, brain waves above approximately 75 Hz (e.g., the high gamma or kappa band) are less easily measured than waves in lower frequency bands. EEG data can be used to determine a person's emotional or mental state, including, for example, attention, emotional engagement, memory, or empathy.

EEG signals can be measured using multiple electrodes placed on the scalp of an individual (e.g., a user, observer, subject, panelist, participant, or patient) to measure voltage fluctuations resulting from electrical activity associated with postsynaptic currents occurring in brain neurons within milliseconds. While subcranial EEG can measure electrical activity with high precision, surface electrodes, such as dry electrodes, also provide useful neural response information.

Many conventional EEG electrodes suffer from high impedance and/or require messy gels to increase signal quality. Additionally, many known EEG headsets utilize helmet or headband-type assemblies that include a limited number of electrodes. These known headsets are uncomfortable to wear and are generally unable to effectively accommodate a variety of head sizes.

For surface EEG electrodes to effectively receive signals from the brain, they must be placed as close to the scalp as possible. Electrodes can be manually placed on the subject's head or incorporated into a wearable device, such as a head-mounted device. However, the subject's hair can interfere with contact between the electrodes and the scalp by limiting the surface area of contact for the electrodes. For example, the average person tends to have between approximately 80 and approximately 200 hair follicles per square centimeter (fs/cm2). The hair strands and follicles between the electrodes and the scalp increase the impedance by several megaohms (MΩ). EEG systems with impedances greater than 100 kiloohms (kΩ) are susceptible to various noise sources that obscure the reading of EEG signals. Impedance can be reduced by applying pressure to the electrodes, thereby reducing the distance between the electrodes and the scalp tissue. However, excessive pressure, such as, for example, greater than 2 Newtons per square millimeter (N/ ^mm2 ), can cause discomfort to the subject. In some examples, the pressure slightly compresses the stratum corneum, the outermost layer of the epidermis, for example, the outermost 10-40 micrometers (µm). Known EEG sensors do not account for the thickness of one or more strands of hair or hair follicles, and do not effectively adjust to the specific size of a user's head. Consequently, known systems are unable to apply an effective amount of pressure to the scalp. In some examples disclosed herein, the profile of the electrodes comprising the electrode head is designed to achieve both comfort and noise reduction. Additionally, in the examples disclosed herein, the head-mounted device incorporating the electrodes is modularly adjustable, also to enhance comfort and noise reduction, as disclosed in greater detail below.

Due to the very low signal amplitude and high impedance of EEG data, noise is an important factor to be considered in high-quality EEG instruments. Noise types can be categorized by various noise sources, such as, for example, skin potential noise, thermal noise, amplifier noise, electrode noise, and interference noise.

Skin potential noise is related to the stretching of the skin, which causes changes in the potential at the electrodes. The examples disclosed herein mitigate skin potential noise by utilizing specialized electrode shapes that reduce the pressure applied by the electrodes to the scalp. Because the skin is stretched and compressed by the example electrodes described herein, there is generally less noise and less noise when the subject moves. The optimized pressure applied by the electrodes to the scalp reduces skin potential noise and increases comfort. Example pressures are less than approximately 2 N/ ^mm² .

Thermal noise is electronic noise generated by the thermal agitation of charge-carrying electronic components. Thermal noise is proportional to impedance and bandwidth and can be expressed by the following equation: _VTH = (4kTBR) ^1/2 , where k is the Boltzmann constant, T is the temperature in Kelvin (K), B is the bandwidth in Hertz, and R is the electrode impedance in Ohms (Ω). For example, at room temperature (T = 300K) and a bandwidth of 150 Hz with a target impedance of 1 MΩ, the thermal noise will be approximately 1 microvolt root mean square (µVrms). Averaging over a number n of independently digitized electrodes improves the signal-to-noise ratio by approximately 1/(n) ^1/2 (see, for example, FIG12B). As disclosed in more detail below, electrode shapes with an effective diameter of less than 0.2 millimeters (mm) allow for up to approximately 100 independently digitized electrodes in an area with a diameter of less than approximately 15 mm. In some example EEG systems, a maximum spatial resolution of approximately 15 mm is achieved at the scalp surface. Examples disclosed herein mitigate thermal noise by averaging readings over multiple electrodes, such as, for example, averaging by a factor of 10 over n=100 electrodes.

Amplifier noise is noise inherent to the amplification process. Amplifier noise is typically small, such as, for example, approximately 0.5 µVrms at a bandwidth of approximately 150 Hz. The examples disclosed herein mitigate amplifier noise by averaging the readings across multiple electrodes, thereby canceling out at least some of the noise. Averaging across n independently digitized electrodes improves the signal-to-noise ratio by approximately 1/(n) ^1/2 (see, for example, FIG. 12B , thus accounting for both thermal noise and amplifier noise). Furthermore, as described above, for example electrode shapes disclosed below having an effective diameter less than 0.2 mm, in the case of more than 100 independently digitized electrodes in an area having a diameter less than approximately 15 mm, and with a maximum spatial resolution of approximately 15 mm at the scalp surface, the examples disclosed herein also mitigate amplifier noise by averaging the readings across multiple electrodes, such as, for example, by averaging by a factor of 10 for n = 100 electrodes.

Interference noise is caused by the presence of external electromagnetic fields (e.g., power lines). Electromagnetic induction noise can infiltrate EEG signals through multiple pathways. For example, electric fields can induce displacement currents into electrode leads, the electrode-skin interface, or various components of the EEG device (e.g., amplifiers, power supplies, etc.). Another source of electromagnetic noise is the common-mode voltage ( _Vc ) on the subject's body, which consists of a static voltage component ( _Vs ) and a power _line induction component ( _Va ). The power line induction component (Va) is caused by displacement current ( _Id ) flowing through parasitic capacitance ( _Cd ). The magnitude of this capacitance is determined by the subject's proximity to the power source. The power line induction component ( _Va ), for example, can be as high as 20V if the subject grasps an insulated power line. Friction creates charge stored in the capacitance ( _Cb ) between the body and the underlying surface. For example, a third person charged in this manner could induce static voltage into the subject if they move close to the subject. The examples disclosed herein enable EEG signals to be shielded from external electromagnetic fields, enhancing the robustness of the EEG signal against electromagnetic noise sources. In some disclosed examples, a Faraday cage is built around the EEG system to decouple it from ambient noise. Additionally, a dedicated shielding electrode with a low-impedance connection to the subject's body ( _Zsh < 100 kΩ) ensures that no displacement currents penetrate the system.

Disclosed herein are example head-mounted devices and accompanying components for receiving neural response data from a user's head. The example head-mounted devices disclosed herein are portable and include a plurality of independently adjustable straps operatively coupled on one end to a first housing housing a processor and on another end to a second housing including an adjustment mechanism.

The example head-mounted devices described herein conform to any head shape while also applying sufficient force to each of the multiple electrodes (e.g., dry electrodes) coupled to the head-mounted device to provide high-quality EEG readings. Some such example head-mounted devices provide a simple, cost-effective, and reliable solution for the use of a large number of dry electrodes. Some such example head-mounted devices ensure comfort for operation through the hair, good electrode contact, and shielding from line noise and (one or more) other types of noise. The examples disclosed herein also include independently adjustable components to enhance comfort and wearability. In addition, the examples disclosed herein greatly increase the number of channels (e.g., electrodes) that can collect signals from the head, as described in detail below, which enhances data collection and analysis.

An example apparatus is disclosed herein that includes a first elongated strap coupled to a first housing positioned near a first ear of a subject and a second housing positioned near a second ear of the subject, the first elongated strap including a first set of electrodes. The example apparatus also includes a second elongated strap coupled to the first housing and the second housing, the second elongated strap including a second set of electrodes. Additionally, the apparatus includes a third elongated strap coupled to the first housing and the second housing, the third elongated strap including a third set of electrodes; and a fourth elongated strap coupled to the first housing and the second housing, the fourth elongated strap including a fourth set of electrodes. Other example apparatuses include fewer or more adjustable straps, for example, three, two, one, five, etc.

In some examples, each of the first, second, third, and fourth elongated straps is rotatably coupled to each of the first and second housings. In some examples, each of the first, second, third, and fourth elongated straps is detachably coupled to each of the first and second housings.

In some examples, the first elongated strap is positioned above the subject's nasion (e.g., the intersection of the frontal bone and two nasal bones) at approximately 10% of the distance between the subject's nasion and the inion (e.g., the protrusion of the occipital bone) measured on the center of the subject's head, the second elongated strap is positioned above the nasion at approximately 30% of the distance, the third elongated strap is positioned approximately halfway between the nasion and the inion, and the fourth elongated strap is positioned above the occipital inion at approximately 30% of the distance.

In some examples, the sum of the number of electrodes in the first, second, third, and fourth electrode groups includes at least 2000 electrodes. In some examples, the number of electrodes or channels can be 3000 electrodes or more. In addition, in other examples, when fewer data channels are needed or desired, there can be fewer electrodes.

In some examples, each of the first, second, third, and fourth elongated straps includes an adjustable elastic strap or band to vary the distance between the elongated strap and the subject's head.

In some examples, the apparatus further comprises one or more additional elongated strips, each additional elongated strip coupled to the first housing and the second housing, and each additional elongated strip comprising a respective additional set of electrodes.

In some examples, the device includes an adjustment mechanism coupled to the first housing and/or the second housing for adjusting the fit of the device on the subject.

In some examples, the first elongated strip includes a plurality of extensions, and the first plurality of electrodes are disposed at respective ends of each extension. In some examples, the extensions are flexible.

In some examples disclosed herein, the electrode comprises at least a portion of a ring. In some examples, the electrode comprises a sphere. In some examples, the electrode comprises a hook. In some examples, the electrode comprises a pin.

In some examples, the electrodes are removably coupled to the respective first, second, third, or fourth elongated strips.

In some examples, the one or more electrodes compress the stratum corneum of the subject with a force of about 1 N/mm ² to about 2 N/mm ² .

In some examples, the disclosed apparatus includes an analog-to-digital converter for converting signals collected by the electrodes into digital data, an amplifier for amplifying the signals, and a signal conditioner for removing noise from the signals. Some such example apparatuses also include: a data processor for analyzing the data according to one or more analysis protocols to determine a subject's mental state; and a transmitter for transmitting at least one of the digital data or the mental state.

In some examples, the device is worn on the subject's head.

Also disclosed herein are example methods that include obtaining electroencephalogram (EEG) data from an apparatus comprising: a first elongated strip coupled to a first housing positioned near a first ear of a subject and a second housing positioned near a second ear of the subject, the first elongated strip comprising a first set of electrodes having at least eight electrodes; and a second elongated strip coupled to the first housing and the second housing, the second elongated strip comprising a second set of electrodes having at least eight electrodes. Some apparatuses used in some such example methods include: a third elongated strip coupled to the first housing and the second housing, the third elongated strip comprising a third set of electrodes having at least eight electrodes; and a fourth elongated strip coupled to the first housing and the second housing, the fourth elongated strip comprising a fourth set of electrodes having at least eight electrodes. Some such example methods also include analyzing the EEG data to determine a mental state of the subject.

Some example methods include converting EEG data collected from electrodes into digital data, amplifying the EEG data, and removing noise from the EEG data. Other example methods include analyzing the data according to one or more analysis protocols to determine the mental state of the observer and/or transmitting at least one of the digital data or the mental state.

Also disclosed herein is a tangible machine-readable storage medium comprising instructions that, when read, cause a machine to at least obtain electroencephalogram (EEG) data from an apparatus comprising: a first elongated strip coupled to a first housing positioned near a first ear of a subject and a second housing positioned near a second ear of the subject, the first elongated strip comprising a first set of at least eight electrodes; and a second elongated strip coupled to the first housing and the second housing, the second elongated strip comprising a second set of at least eight electrodes. Some such example apparatuses further comprise: a third elongated strip coupled to the first housing and the second housing, the third elongated strip comprising a third set of at least eight electrodes; and a fourth elongated strip coupled to the first housing and the second housing, the fourth elongated strip comprising a fourth set of at least eight electrodes. Some example instructions cause a machine to analyze the EEG data to determine a mental state of the subject.

Some example instructions cause the machine to convert EEG data collected from the electrodes into digital data, amplify the EEG data, and remove noise from the EEG data. Some instructions cause the machine to analyze the data according to one or more analysis protocols to determine a mental state and transmit at least one of the digital data or the mental state.

The example device disclosed herein includes a central body portion, such as a spine, and a plurality of extensions extending from the central body portion, each extension having a distal end coupled to an electrode. The example device also includes an adjustment strap disposed along a longitudinal axis of the central body for adjusting the position of the extensions.

In some examples, the adjustment strap is elastic. In addition, in some examples, the adjustment strap has a circular cross-section. In other examples, the adjustment strap has a rectangular cross-section. In some examples, the adjustment strap is slidably disposed along the longitudinal axis.

In some examples disclosed herein, the central body portion includes a first protrusion, a second protrusion, and a recess formed between the first and second protrusions, and the adjustment strap is disposed in the recess. In some examples, the central body portion and the extension portion comprise one or more of silicone or rubber. Furthermore, in some disclosed examples, the device includes a flexible printed circuit board encapsulated within the central body portion and the extension portion.

In some examples, each extension curves away from the central body portion. In some such examples, each extension curves in the same direction. Furthermore, in some examples, a first extension is located directly across from a second extension across from the central body portion. In some examples, the central body portion and the extensions are flexible but inelastic, while the adjustment strap is flexible and elastic.

In some examples, the electrodes are resilient (e.g., springy). Furthermore, in some examples, the electrodes are detachable. In some examples, the example electrodes comprise at least a portion of a ring. The example devices, in some examples, further comprise an electrode array disposed on one side of the central body portion. In some examples, the array is an embossed plate, and the device comprises up to 256 electrodes.

In some examples, tightening the adjustment strap causes the electrodes to apply a force to the head of the subject wearing the device. In some examples, the force is approximately the same at each electrode.

In some examples, the disclosed devices include a silver nylon coating.

Some example devices disclosed herein include an analog-to-digital converter for converting a signal obtained from the electrodes into a digital signal. Additionally, some example devices include a signal conditioner for performing at least one of the following: amplifying the signal obtained from the electrodes or removing noise from the signal.

In some examples, the device includes a cover that partially surrounds the electrode such that a first portion of the cover is disposed on a first side of the electrode, a second portion of the cover is disposed on a second side of the electrode, and a distal end of the electrode that contacts the subject's tissue extends from the cover. In some examples, the electrode has a cross-section less than about 0.5 mm, a first outer end of the first portion of the cover and a second outer end of the second portion of the cover are separated by a distance less than about 1 mm, and the distal end of the electrode that contacts the tissue extends less than about 0.2 mm from the cover.

Another example method disclosed herein includes obtaining electroencephalogram (EEG) data from a device worn by a subject, the device comprising a central body portion and a plurality of extensions extending from the central body portion, each extension having a distal end coupled to an electrode. The device of some such example methods further includes an adjustment strap disposed along a longitudinal axis of the central body portion for adjusting the position of the extensions. Some such example methods further include analyzing the data to determine the subject's mental state.

Some example methods also include one or more of converting the signal obtained from the electrode to a digital signal, amplifying the signal obtained from the electrode, and/or removing noise from the signal.

Another example tangible machine-readable storage medium disclosed herein includes instructions that, when read, cause a machine to at least obtain electroencephalogram (EEG) data from a device worn by a subject. Some such example instructions include a device comprising: a central body portion; a plurality of extensions extending from the central body portion, each extension having a distal end coupled to an electrode; and an adjustment strap disposed along a longitudinal axis of the central body portion for adjusting the position of the extensions. Some example instructions further cause the machine to analyze the data to determine the subject's mental state.

Some example instructions further cause the machine to perform one or more of: converting the signal obtained from the electrode into a digital signal, amplifying the signal obtained from the electrode, and/or removing noise from the signal.

Some example devices disclosed herein include: a first band including a first set of electrodes; and a second band including a second set of electrodes. In some examples, the first band and the second band are oriented in a first direction to obtain first neural response data from a subject, and the first band and the second band are oriented in a second direction to obtain second neural response data from the subject, the second direction being substantially perpendicular to the first direction.

In some examples, the first band has a first end and a second end, the second band has a third end and a fourth end, the first end is coupled to the third end, and the second end is coupled to the fourth end. Furthermore, in some examples, the first end is coupled to the third end via a first housing, and the second end is coupled to the fourth end via a second housing. In some examples, the second housing includes a processor for analyzing data collected from the electrodes. Furthermore, in some examples, the first housing includes an adjustment mechanism for adjusting the fit of the device on the subject.

In some examples, the device is oriented in the second orientation to collect midline readings from the subject's brain.

Other example methods disclosed herein include obtaining first neural response data from a subject with an apparatus oriented in a first orientation. The apparatus of some such example methods includes: a first band comprising a first set of electrodes; and a second band comprising a second set of electrodes. The example methods also include obtaining second neural response data from the subject with the apparatus oriented in a second orientation, the second orientation being substantially perpendicular to the first orientation.

Some example methods also include analyzing, using a processor disposed in the second housing, data collected from the electrodes. Additionally, some example methods include collecting a midline reading from the subject's brain with the device in the second orientation.

Also disclosed herein is a tangible machine-readable storage medium comprising instructions that, when read, cause a machine to obtain at least first neural response data from a subject with an apparatus oriented in a first orientation, the apparatus comprising: a first band comprising a first set of electrodes; and a second band comprising a second set of electrodes. Some example instructions further cause the machine to obtain second neural response data from the subject with the apparatus oriented in a second orientation, the second orientation being perpendicular to the first orientation.

Some example instructions further cause the machine to analyze data collected from the electrodes using a processor disposed in the second housing.Some example instructions further cause the machine to collect a midline reading from the subject's brain with the device in the second orientation.

Also disclosed herein is an example apparatus comprising: a first set of electrodes for reading electrical signals from tissue of a subject; and a second set of electrodes for reading the electrical signals. In such an example, the first and second sets of electrodes are mechanically coupled to a head-mounted device. Furthermore, in the example apparatus, the first set of electrodes comprises electrodes of a first type, and the second set of electrodes comprises electrodes of a second type different from the first type.

In some examples, the first type of electrode comprises individually mounted electrodes, and the second type of electrode comprises an array of electrodes. In some examples, two or more electrodes in the array can be electrically shorted to form a single electrode having an increased surface area. Furthermore, in some examples, the first type of electrode comprises at least one of a partial ring, a ball point, and/or a hook. Furthermore, in some examples, the first group is positioned along a first outer side of the elongated strip and along a second outer side of the elongated strip, and the second group is positioned along a central axis of the elongated strip.

Some example methods disclosed herein include reading electrical signals from tissue of a subject using a first set of electrodes. Some such example methods also include reading the electrical signals using a second set of electrodes, wherein the first and second sets of electrodes are mechanically coupled to a head-mounted device, and wherein the first set of electrodes includes electrodes of a first type and the second set of electrodes includes electrodes of a second type different from the first type.

Also disclosed herein is a tangible machine-readable storage medium comprising instructions that, when read, cause a machine to read at least an electrical signal from tissue of a subject using a first set of electrodes and a second set of electrodes. The first and second sets of electrodes for use with such example instructions are mechanically coupled to a head-mounted device, wherein the first set of electrodes comprises electrodes of a first type and the second set of electrodes comprises electrodes of a second type different from the first type.

Some example devices disclosed herein include a first housing including a magnetic lock. Some such example devices also include a first elongated strap having a first end adjustably coupled to the first housing. The first elongated strap includes a first plurality of electrodes. Some such example devices also include a first adjustable strip. The first adjustable strip includes a first magnetic fastener for magnetically linking with the magnetic lock at a first engagement point to secure the first elongated strap in a first position, and for magnetically linking with the magnetic lock at a second engagement point to secure the first elongated strap in a second position.

In some examples, the device is worn on a subject's head, wherein the first position is closer to the top of the head than the second position, and adjustment of the first magnetic fastener from the first position to the second position tightens the first elongated strap and brings the electrode closer to the head. In some examples, the first elongated strap is removably coupled to the first housing.

Some such example devices further include a second elongated strap having a second end adjustably coupled to the first housing. The second elongated strap includes a second plurality of electrodes. Some such example devices further include a second adjustable strip. The second adjustable strip includes a second magnetic fastener for magnetically linking with the magnetic lock at a third engagement point to secure the second elongated strap in a third position, and for magnetically linking with the magnetic lock at a fourth engagement point to secure the second elongated strap in a fourth position.

In some examples, the first elongated strap and the second elongated strap are independently adjustable. Additionally, in some examples, the first elongated strap and the second elongated strap are independently removable.

Other methods disclosed herein include releasing a first magnetic fastener of an adjustable strap of a first elongated strap of a device from a first engagement point with a magnetic lock of a first housing to unlock the first elongated strap from a first position. Some such example methods also include coupling the first magnetic fastener to the magnetic lock at a second engagement point to secure the first elongated strap in a second position.

Some example methods include releasing a second magnetic fastener of an adjustable strip of a second elongated strap of the device from a third engagement point with the magnetic lock to unlock the second elongated strap from the third position. Some example methods also include coupling the second magnetic fastener to the magnetic lock at a fourth engagement point to secure the second elongated strap in the fourth position.

Additionally, some example methods include one or more of independently adjusting the first elongated strap and the second elongated strap and/or independently removing the first elongated strap and the second elongated strap.

Some example devices disclosed herein include a first hub and a first detachable belt comprising a first plurality of electrodes detachably coupled to the first hub. In some such examples, the first belt includes a first cover comprising at least one of nylon or silver. The first belt is washable in an automatic washing machine. In some examples, the cover is stretchable. In some examples, the device includes a second detachable, washable belt comprising a second plurality of electrodes. Furthermore, in some examples, the first detachable belt is adjustably coupled to the first hub and can be used with a first subject having a first head size and a second subject having a second head size, the second head size being different from the first head size.

Some example methods disclosed herein include removing a first removable belt comprising a first plurality of electrodes from a first hub, the first belt comprising a first cover comprising at least one of nylon or silver. Some such example methods also include washing the first belt in an automated washing machine. Additionally, some example methods include: removing a second removable, washable belt comprising a second plurality of electrodes from the first hub; and washing the second belt in an automated washing machine. Additionally, some example methods include adjusting the first removable belt relative to the first hub to fit a first subject having a first head size and/or readjusting the first removable belt relative to the first hub to fit a second subject having a second head size, the second head size being different from the first head size.

Some example methods disclosed herein include obtaining electroencephalogram (EEG) data from a subject via an apparatus comprising two or more independently adjustable bands, each band having a plurality of electrodes for detecting EEG data from the subject's brain, each band being selectively rotatable relative to an adjacent band, and each band being selectively compressible to increase the force of the electrodes against the patient's head. Some such example methods include converting the EEG data into a digital EEG signal and conditioning the digital EEG signal. Additionally, some such example methods include analyzing the digital EEG signal using one or more analysis protocols to determine a mental profile of the subject, and transmitting the mental profile to an output device.

In some example methods, the device further comprises a processor for performing the conversion, conditioning, analysis, and transmission. In some examples, the conversion occurs at each electrode. In some examples, the device comprises at least 2000 electrodes.

In some example methods, the apparatus includes a wireless transmitter for transmitting the mental signature. In some examples, the conditioning includes at least one of amplifying the digital EEG signal or filtering the digital EEG signal.

In some examples, the output device includes one or more of a handheld device, an alarm, a display screen on the device, a remote server, or a remote computer. In some example methods, the output device is configured to perform at least one of the following: issuing an alarm, displaying a message, presenting an alarm on a screen, issuing a report to a local computer, or issuing a report to a remote computer. Furthermore, in some examples, the mental characteristic includes one or more of a mental state, a health condition, a physiological state, a level of attention, a level of empathy, a memory attribute, or an indicator of emotional engagement.

Also disclosed herein is a tangible, machine-accessible storage medium comprising instructions that, when executed, cause a machine to obtain at least electroencephalogram (EEG) data from a subject wearing a device comprising two or more independently adjustable bands, each band having a plurality of electrodes for detecting EEG data from the subject's brain, each band being selectively rotatable relative to an adjacent band, and each band being selectively compressible to increase force of the electrodes against the patient's head. In some examples, the instructions further cause the machine to convert the EEG data into a digital EEG signal, condition the digital EEG signal, analyze the digital EEG signal using one or more analysis protocols to determine a mental profile of the subject, and transmit the mental profile to an output device. In some examples, the storage medium is disposed within the device.

Some example systems disclosed herein include an apparatus for obtaining electroencephalogram (EEG) data from a subject, the apparatus comprising two or more independently adjustable bands, each band having a plurality of electrodes for detecting EEG data from the subject's brain, each band being selectively rotatable relative to an adjacent band, and each band being selectively compressible to increase the force of the electrodes against the patient's head. The example systems also include an analog-to-digital converter for converting the EEG data into a digital EEG signal and a signal conditioner for conditioning the digital EEG signal. Some such example systems also include a processor for analyzing the digital EEG signal using one or more analysis protocols to determine a mental characteristic of the subject, and a transmitter for transmitting the mental characteristic to an output device.

In some example systems, the analog-to-digital converter, signal conditioner, processor, and transmitter are located on the device. Some example systems include an analog-to-digital converter at each electrode. Some example systems also include a signal conditioner at each electrode. Some example systems include a detrending unit to compensate for polarization of the electrodes.

The example method disclosed herein includes: evaluating a first attribute of a first neural signal; determining whether the first neural signal complies with a quality threshold based on the first attribute; evaluating a second attribute of a second neural signal; and determining whether the second neural signal complies with the quality threshold based on the second attribute. The example method also includes: adjusting the first neural signal to obtain a third neural signal when the first neural signal does not comply with the quality threshold; and adjusting the second neural signal to obtain a fourth neural signal when the second neural signal does not comply with the quality threshold. In addition, the example method includes: evaluating a third attribute of a third neural signal; determining whether the third neural signal complies with the quality threshold based on the third attribute; evaluating a fourth attribute of a fourth neural signal; and determining whether the fourth neural signal complies with the quality threshold based on the fourth attribute. The example method also includes selecting a first one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal based on the corresponding compliance with the quality threshold to perform at least one of the following: use for additional analysis, ignore, or merge with a second one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal.

In some examples, the method occurs on a head-mounted device configured to collect the first neural signal and the second neural signal. In some examples, the first, second, third, and fourth attributes include at least one of strength, amplitude, signal-to-noise ratio, or duration of the corresponding first, second, third, or fourth neural signal.

In some example methods, compliance with the quality threshold is based on a comparison of the first, second, third, or fourth neural signal to a reference value. In some such examples, the reference value comprises an absolute threshold, a spectral threshold, a slope rate threshold, or a low activity threshold.

In some example methods, the conditioning comprises amplifying the first or second neural signal or filtering at least one of the first or second neural signal. In some examples, the omitting or combining is performed by a switching circuit communicatively coupled to a first channel through which the first neural signal is collected and a second channel through which the second neural signal is collected.

Also disclosed herein is a tangible, machine-accessible storage medium comprising instructions that, when executed, cause the machine to at least evaluate a first attribute of a first neural signal, determine whether the first neural signal complies with a quality threshold based on the first attribute, evaluate a second attribute of a second neural signal, and determine whether the second neural signal complies with the quality threshold based on the second attribute. The example instructions further cause the machine to adjust the first neural signal to obtain a third neural signal when the first neural signal does not comply with the quality threshold, adjust the second neural signal to obtain a fourth neural signal when the second neural signal does not comply with the quality threshold, evaluate a third attribute of the third neural signal, determine whether the third neural signal complies with the quality threshold based on the third attribute, evaluate a fourth attribute of the fourth neural signal, and determine whether the fourth neural signal complies with the quality threshold based on the fourth attribute. Additionally, the instructions cause the machine to select a first one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal based on the respective compliances with the quality threshold to perform at least one of the following: for additional analysis, to ignore, or to merge the second one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal with the second one.

In some examples, the storage medium is disposed within a head-mounted device configured to collect the first neural signal and the second neural signal. In some examples, the instructions further cause the machine to adjust one or more of the first neural signal or the second neural signal by amplifying the first neural signal or the second neural signal or filtering the first neural signal or the second neural signal.

In some examples, the instructions further cause the machine to ignore one or more of the first, second, third, or fourth neural signals or to merge two or more of the first, second, third, or fourth neural signals by actuating a switching circuit communicatively coupled to a first channel through which the first neural signal is collected and a second channel through which the second neural signal is collected.

Disclosed herein is an example system comprising a head-mounted device for collecting a first neural signal and a second neural signal from a subject's brain. The example system further comprises a processor configured to evaluate a first attribute of the first neural signal, determine whether the first neural signal complies with a quality threshold based on the first attribute, evaluate a second attribute of the second neural signal, and determine whether the second neural signal complies with the quality threshold based on the second attribute. In the example system, the processor modulates the first neural signal to obtain a third neural signal when the first neural signal does not comply with the quality threshold, modulates the second neural signal to obtain a fourth neural signal when the second neural signal does not comply with the quality threshold, evaluates a third attribute of the third neural signal, determines whether the third neural signal complies with the quality threshold based on the third attribute, evaluates a fourth attribute of the fourth neural signal, and determines whether the fourth neural signal complies with the quality threshold based on the fourth attribute. In the example system, the processor further selects a first one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal based on the respective compliances with the quality threshold to perform at least one of the following: perform additional analysis, ignore, or merge the second one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal with the second one of the first neural signal, the second neural signal, the third neural signal, or the fourth neural signal.

In some examples, the system includes a switching circuit that is selectively communicatively coupled to a first channel for collecting a first neural signal and selectively communicatively coupled to a second channel for collecting a second neural signal to perform at least one of the following: ignoring one or more of the first, second, third, or fourth neural signals or combining two or more of the first, second, third, or fourth neural signals.

Some example methods disclosed herein include monitoring an activity of a patient in a home environment and analyzing first data collected from a first sensor coupled to the patient to determine a first characteristic of the patient, the first sensor comprising electrodes coupled to the patient's head. The example methods also include analyzing second data collected from a second sensor coupled to the patient to determine a second characteristic of the patient; determining a health assessment of the patient based on the activity, the first characteristic, and the second characteristic; and generating an output signal based on the health assessment.

In some example methods, the second data is wirelessly transmitted to a device housing the first sensor. In some examples, the second sensor comprises one or more of a biometric sensor, a neural sensor, or a physiological sensor. In some examples, the second sensor comprises an electrocardiogram (ECG), a glucose monitoring system, an electrooculography (EOG) system, a facial monitoring system, or a plug-in/plug-and-play device. In some example methods, the second sensor comprises an eye-tracking sensor, a galvanic skin response (GSSR) sensor, an electromyography (EMG) instrument, a camera, an infrared sensor, an interaction speed detector, or a touch sensor. In some examples, the second sensor comprises a full-face or half-face covering camera.

Some example methods further include comparing the health assessment to a reference assessment and transmitting at least one of the health assessment or the output signal to a remote facility. In some such examples, the remote facility includes at least one of a doctor's office, a hospital, a clinic, a laboratory, an archive, a research facility, or a diagnostic facility.

In some example methods, the output signal is coupled to an alarm. In some such examples, the alarm includes at least one of a light, a sound, or a display. In some examples, the output signal is used to activate an automated delivery device to automatically administer the medication to the patient. Some example methods further include prompting the patient regarding the input based on the health assessment.

Some example methods further include tracking the patient's location via a global positioning system (GPS) device. In some such examples, the GPS device is disposed within the device housing the first sensor. Some example methods further include logging the health assessment over a period of time.

Disclosed herein is a tangible machine-accessible storage medium comprising instructions that, when executed, cause a machine to at least monitor an activity of a patient in a home environment and analyze first data collected from a first sensor coupled to the patient to determine a first characteristic of the patient, the first sensor comprising electrodes coupled to the patient's head. The instructions further cause the machine to analyze second data collected from a second sensor coupled to the patient to determine a second characteristic of the patient, determine a health assessment of the patient based on the activity, the first characteristic, and the second characteristic, and generate an output signal based on the health assessment.

An example system is disclosed herein, comprising: a first sensor for collecting first data from a patient, the first sensor comprising electrodes coupled to the patient's head; and a second sensor for collecting second data from the patient, the second sensor coupled to the patient. The example system also includes a processor for monitoring the patient's activity in a home environment, analyzing the first data collected from the first sensor to determine a first characteristic of the patient, analyzing the second data collected from the second sensor to determine a second characteristic of the patient, determining a health assessment of the patient based on the activity, the first characteristic, and the second characteristic, and generating an output signal based on the health assessment.

An example method disclosed herein includes analyzing first data collected from a first sensor of a head-mounted device coupled to a subject while the subject is exposed to media to determine a first behavior of the subject, the first sensor comprising electrodes coupled to the subject's head; and determining a mental state of the subject based on the first behavior. The example method also includes analyzing second data collected from a second sensor to determine a second behavior of the subject; and determining an expected activity of the subject based on the mental state and the second behavior.

In some example methods, the first behavior is a change in brain activity. In some examples, the second behavior is a direction of gaze. In some examples, the mental state is a level of engagement.

In some example methods, the desired activity is an actuation of an electronic device. In some such examples, the actuation of the electronic device is a change in at least one of the volume, mute state, channel, or power state of a device presenting the media. In some examples, the actuation of the electronic device is a cursor movement, a keystroke, or a mouse click. Some example methods further include sending a signal from the head-mounted device to the electronic device to complete the desired activity.

In some example methods, the analyzing of the first data includes analyzing an electroencephalographic signature in the somatosensory system, the electroencephalographic signature being centered on the sensorimotor cortex contralateral to the movement and including changes in mu and beta frequencies.

In some examples, the expected activity is consumption of the media. Some such example methods further include identifying the program in the media by at least one of detecting a channel, collecting an audio code indicative of the program, or examining time-stamped data at a remote data collection facility. Other examples include determining a viewership based on the expected activity and the program identification.

Disclosed herein is a tangible, machine-accessible storage medium comprising instructions that, when executed, cause the machine to: analyze at least first data collected from a first sensor of a head-mounted device coupled to a subject while the subject is exposed to media to determine a first behavior of the subject, the first sensor comprising electrodes coupled to the subject's head; and determine a mental state of the subject based on the first behavior. The instructions also cause the machine to: analyze second data collected from a second sensor to determine a second behavior of the subject; and determine an expected activity of the subject based on the mental state and the second behavior.

An example system is disclosed herein, comprising: a first sensor for collecting first data, the first sensor being disposed in a head-mounted device coupled to a subject while the subject is exposed to media, the first sensor comprising electrodes coupled to the subject's head; and a second sensor for collecting second data from the subject. The example system also includes a processor for analyzing the first data collected from the first sensor to determine a first behavior of the subject, determining a mental state of the subject based on the first behavior, analyzing the second data collected from the second sensor to determine a second behavior of the subject, and determining an expected activity of the subject based on the mental state and the second behavior.

Some example methods disclosed herein include placing a head-mounted device on a user's head in a first orientation, the head-mounted device including one or more independently adjustable bands disposed on the user's head, each band having a plurality of electrodes for receiving electrical signals from the user's brain. The method also includes adjusting the position of the electrodes on the user's head by selectively rotating one or more bands relative to corresponding adjacent bands; and adjusting the compression of the electrodes on the user's head by selectively varying the effective length of corresponding elastic strips associated with the corresponding bands to vary the force of the electrodes on the head. Additionally, the example method includes obtaining electroencephalogram (EEG) data from the electrodes; conditioning the EEG data; and analyzing the EEG data to determine the user's mental state.

In some example methods, adjusting includes one or more of converting the signal to a digital signal, amplifying the signal, or filtering the signal. In some examples, the adjusting occurs in a head-mounted device. Some example methods also include evaluating the quality of the EEG data obtained from the electrodes and determining whether the electrode positions should be adjusted based on the quality.

Some example methods further include adjusting the position of the electrodes, including physically moving one or more electrodes.Some such example methods further include rotating the one or more bands to a second orientation on the user's head.

In some examples, adjusting the position of the electrodes includes virtually moving one or more electrodes. Some such examples also include short-circuiting a portion of the electrodes when the quality of EEG data obtained from the plurality of electrodes is below a threshold quality.

Some example methods also include outputting a signal based on the mental state to one or more of a medical system, an audience measurement facility, or a remote device.

Disclosed herein is a tangible machine-accessible storage medium comprising instructions that, when executed, cause the machine to at least obtain electroencephalogram (EEG) data from a head-mounted device comprising one or more independently adjustable bands disposed on a user's head, each band having a plurality of electrodes for receiving electrical signals from the user's brain. The instructions further cause the machine to adjust the position of the electrodes on the user's head, adjust the EEG data, and analyze the EEG data to determine the user's mental state.

Some example systems disclosed herein include a head-mounted device for obtaining electroencephalogram (EEG) data from a user, the head-mounted device including one or more independently adjustable bands disposed on the user's head, each band having a plurality of electrodes for receiving electrical signals from the user's brain, each band selectively rotatable relative to a corresponding adjacent band to adjust the position of the electrodes, and each band including a corresponding elastic strip that is operative to be lengthened or shortened to adjust the compression of the electrodes on the user's head. The example system also includes a processor for receiving the EEG data from the electrodes, conditioning the EEG data, and analyzing the EEG data to determine the user's mental state.

Turning now to the drawings, Figures 1-4 illustrate an example head-mounted device 100. This example head-mounted device can be used, for example, to collect medical information from patients in medical or home settings, to control aspects of gaming or other entertainment, to provide data as part of a fitness program, to collect audience measurement data, to control remote devices, and/or for a variety of other uses. The example head-mounted device 100 of Figure 1 includes multiple independently adjustable bands, each of which includes multiple electrodes for receiving signals from the head of a user, subject, observer, and/or panelist. As used herein, a participant is an individual who consents to be monitored. Typically, participants provide their demographic information (e.g., age, race, income, etc.) to a monitoring entity (e.g., the Nielsen Company), which collects and compiles data on topics of interest (e.g., media exposure). More specifically, the illustrated example head-mounted device 100 includes a first band 102, a second band 104, a third band 106, and a fourth band 108. Each of the bands 102-108 includes multiple electrodes. In the illustrated example, the electrodes are partial ring electrodes. The ring electrodes can have, for example, a diameter of less than about 3 mm and a length of less than about 3 mm. The larger and wider the electrodes, the greater the force required to adequately apply the electrodes to the scalp. In some examples, the electrodes have a diameter of about 1 mm to about 2 mm. However, many other types, sizes, and/or shapes of electrodes may additionally or alternatively be used, as discussed in further detail below. In the example of FIG. 1 , straps 102-108 are intended to extend over the user's head from the left side of the head to the right side of the head. Each strap 102-108 comprises an elongated structure having a longitudinal axis. In this example, each strap 102-108 takes the form of a ridged structure 110, 112, 114, and 116, respectively. Each ridge 110, 112, 114, 116 supports an elastic adjustment strap or strip 118, 120, 122, and 124, respectively. Each strap 102-108 is rotatably and removably coupled to a first housing 126 on one side and rotatably and removably coupled to a second housing 128 on the other side. For example, the straps 102-108 may include snaps and/or pivot-type connections for inserting the straps 102-108 into the head-mounted device. In other examples, the straps are fixedly coupled to the head-mounted device. In the example shown, the first housing 126 can be placed near the user's right ear, and the second housing 128 can be placed near the user's left ear, so that the straps 102-108 are positioned on the user's head for reading electrical activity along the scalp. The illustrated example head-mounted device 100 also includes an additional support strap 130, which is adjustable and can be, for example, elastic or any other suitable material that can be used to tighten and secure the head-mounted device 100 around the back of the user's head. In the example shown, the head-mounted device 100 includes four straps. However, in other examples, the head-mounted device 100 can include fewer or more (e.g., three or fewer or ten or more) adjustable bands. Each band can carry about eight to about 256 or more electrodes per band.

In the example of FIG1 , the straps 102-108 are rotatably and removably coupled to the first and second housings 126 and 128 to allow the user to adjust the position of the straps 102-108 on the user's head. The straps 102-108 of this example can be rotated toward the user's inion (the bump of the occipital bone) or nasion (the intersection of the frontal bone and the two nasal bones) to position the electrodes in a specific location for measuring electrical activity. Each ridge 110-116 of FIG1 is comprised of a flexible material, such as plastic, rubber, polyurethane, silicone, and/or any other suitable material. The flexibility of the example ridges 110-116 allows the head-mounted device 100 to rest comfortably on the user's head. Furthermore, the illustrated example elastic strips 118-124 are supported by the ridges 110-116 and can be pulled downward to tighten the ridges 110-116, thereby increasing the pressure of the electrodes against the user's scalp. In the illustrated example, the elastic strips 118-124 are flexible and elastic. Additionally, the elastic strips 118-124 of FIG. 1 are slidably and translatably coupled to the spines 110-116. Furthermore, in the example of FIG. 1 , the entire headset 100 and/or the individual straps 102-108 can be laundered in a typical washing machine for routine cleaning and/or the headset 100 can be disinfected and sterilized, such as between uses or between users. In some examples, various templates for headsets are available for heads of different sizes. People have different head sizes based on age, gender, race, and/or genetics. For example, a human head may have a circumference ranging from approximately 54 cm to approximately 65 cm. In some examples, two or three template headsets may be available. For example, a first template may accommodate a head with a circumference of approximately 56 cm, a second template may accommodate a head with a circumference of approximately 59 cm, and a third template may accommodate a head with a circumference of approximately 62 cm. In these examples, the center straps (e.g., along the midline) may be approximately 23 cm, approximately 25 cm, and approximately 26 cm, respectively. Thus, in some examples, the templates can include multiple sizes of straps with length differences between the different templates ranging from about 1 cm to about 2 cm. The different template sizes are used as coarse adjustments when fitting the head-mounted device to the subject. Adjustment of the elongated straps is then used to refine the fit as fine adjustments, as described in more detail below.

In the illustrated example, the first housing 126 includes an example adjustment mechanism 132 (shown in FIG. 10 ) for adjusting the length of the elastic strips 118-124. The illustrated example elastic strips 118-124 can be tightened via the adjustment mechanism 132 to position the corresponding straps 102-108 and tighten the ridges 110-116 downwardly toward the scalp. An example adjustment method is disclosed in more detail below in conjunction with FIG. 10 .

In the illustrated example, the second housing 128 supports electrical components 134, disclosed in more detail below, such as, for example, a processor for processing signals from the electrodes. In some examples, this processing occurs at the headset as an integrated or self-contained system. In other examples, some processing occurs at the headset, while some processing occurs remotely, such as after the headset transmits data or semi-processed results to a remote site via a wireless connection. In still other examples, all data is streamed to a remote analyzer for processing. The electrical components 134 of the illustrated example are used, for example, to convert EEG data from analog to digital, amplify the EEG data, remove noise from the data, analyze the data, and transmit the data to a computer or other network. The illustrated example second housing 128 includes hardware and software, such as, for example, an amplifier, a signal conditioner, a data processor, and/or a transmitter for transmitting signals to a data center or computer. Each spine 110-116 of the illustrated example is communicatively coupled to the electrical components, including the example processor, via a wired connection and/or wirelessly. In other examples, the electrical components 134 are supported in the first housing 126 , and the adjustment mechanism 132 is supported on or in the second housing 128 .

FIG4A illustrates a perspective view of the head-mounted device 100 worn on a user's head. As shown, the straps 102-108 span the head from left to right. The position of the straps 102-108 can be adjusted, and the elastic strips 118-124 can be tightened to tighten the straps 102-108 downwardly against the user's head. In the example shown, an additional support strap 130 extends around the back of the head and can be tightened or adjusted to secure the head-mounted device 100 to the user's head.

As shown in FIG4B , in addition to being worn in the side-to-side orientation described above, the illustrated example head-mounted device 100 can be worn in a front-to-back orientation, with either the first housing 126 or the second housing 128 placed on the user's forehead, and the straps 102-108 spanning to the other of the second housing 128 or the first housing 126, which is positioned on the back of the user's head. The straps 102-108 can be individually adjusted and/or tightened laterally for optimal readings. The orientation of FIG4 facilitates midline readings through the head-mounted device 100.

FIG5 illustrates an example strap 102 that may be used with the head-mounted device 100. As can be seen, the first strap 102 is comprised of a first spine 110 and a first elastic strip 118. The first spine 110 is designed as a ridge-like structure having a plurality of opposing extensions 136a-136t, similar to the arrangement of a spine and vertebrae. Each extension 136a-136t is coupled to a partial ring electrode 138a-138t. The extensions 136a-136t are flexible, thereby retracting and flexing as the first strap 102 is tightened downwardly on the user's head. In the example shown in FIG5 , the electrodes 138a-138t are molded within the extensions 136a-136t of the first spine 110. However, in other examples, the electrodes 138a-138t may be removably coupled to the extensions 136a-136t (e.g., snapped onto the extensions 136a-136t). Each electrode 138a-138t has its own channel running through the spine 110. In addition, in some examples, readings from multiple electrodes can be averaged together to increase the effective surface area between the electrodes and the scalp and reduce impedance, as disclosed in more detail below. The first spine 110 also includes a housing 140, which can contain individual amplifiers and analog-to-digital converters for each electrode channel. The spine 110 also includes wires 142 for communicatively coupling the electrodes 138a-138t to the processor 134 and/or other electrical components of the second housing 128 for processing. In other examples, the spine 110 includes a wireless transmitter and power supply, for example in the housing 140, for wirelessly transmitting data to the processor 134 in the second housing 128 or to another processor outside the head-mounted device 100.

The top side of the first ridge 110 includes a plurality of runners 144a-144j, which are extensions or protrusions used to guide and secure the first elastic strip 118 along the top side of the first ridge 110. In the illustrated example, the runners 144a-144j are formed as a pair of two elongated runners extending along opposing sides of the elastic strip 118. In other examples, the runners 144a-144j are implemented as one or more elongated circular tubes running over the elastic strip 118. The first ridge 110 also includes a first eye 146 and a second eye 148. In the illustrated example, the second eye 148 is coupled to the housing 140. The first elastic strip 118 is disposed between the runners 144a-144j along the longitudinal axis on the top side of the first ridge 110 and passes through the first and second eyes 146, 148. The first and second eyes 146, 148 help maintain the position of the elastic strip 118 on the ridge 110. The first elastic strip 118 is slidably engaged along the top side of the first ridge 110 so as to slide as the first elastic strip 118 is stretched and tightened or released. In the example shown in FIG5 , the first elastic strip 118 has a circular cross-section. However, in other examples, the first elastic strip 118 has a rectangular, oval, or any other cross-sectional shape. In some examples, the elastic strip 118 is shaped to enhance shielding of electronic signals propagating through the ridge 110.

5 , the first strip 102 includes 20 electrodes on the first ridge 110. However, in other examples, the first ridge 110 may carry other numbers of electrodes (eg, 256 or more individual electrodes).

FIG6 is an enlarged view of a portion of first band 102. As can be seen in FIG6 , extensions 136a-136c and 136k-136m are slightly downwardly curved, positioning electrodes 138a-138c and 138k-138m downwardly toward the scalp. As shown in FIG6 , first elastic strip 118 is positioned along the top of first ridge 110 and held in place by rails 144a-144c and first eye 146. Each extension 136a-136c and 136k-136m is coupled to a corresponding one of electrodes 138a-138c and 138k-138m. As the first elastic strip 118 is pulled tighter, the elastic strip 118 effectively shortens, thereby generating a downward force on the extensions 136a-136c and 136k-136m, which flex upward or bend outward to force the electrodes against the user's scalp. Example bands 102-108 are designed to generate a force of about 1 N/ ^mm2 to about 2 N/ ^mm2 on the user's scalp. In some examples, the applied force is the same for each electrode.

FIG7 is a cross-sectional view of first strap 102 having first spine 110 and first elastic strap 118. Extensions 136a and 136k are downwardly curved. Electrodes 138a and 138k are partially annular electrodes coupled to the undersides of extensions 136a and 136k, respectively. The ends of electrodes 138a and 138k are molded into first spine body 110 and operatively coupled to a printed circuit board (PCB) 150 that runs through first spine 110. Each electrode 138a-138t (shown in FIG5 ) is communicatively coupled to PCB 150. The illustrated example PCB 150 includes three electronic layers (e.g., layers containing at least one electrical component or circuitry) and a shielding layer.

Disclosed herein are several example methods of shielding for reducing or eliminating electromagnetic interference with EEG readings, including, for example, reducing impedance to reduce and/or eliminate the need for external shielding in some instances. The examples disclosed herein utilize a high-impedance skin-electrode interface and a high impedance mismatch between electrodes to achieve high-resolution EEG measurements. In some examples, the high-resolution measurements are achieved by a battery-powered EEG measurement device (such as, for example, a head-mounted device disclosed herein), which can include a floating drive low-impedance ground, wireless communication, and the shielding techniques disclosed in the examples. Figures 8A, 8B, and 8C illustrate the effects of impedance represented by example circuits for an EEG system without an external noise source (Figure 8A), a wet-electrode EEG system with an external noise source (Figure 8B), and a dry-electrode EEG system with an external noise source (Figure 8C), representing the example systems disclosed herein.

FIG8A illustrates an example EEG system 800 in which a subject 802 is coupled to an EEG measurement device 804, such as, for example, a head-mounted device disclosed herein. In this example, head-mounted device 804 is a wireless EEG measurement device. Biopotential electrodes are applied to the head of subject 802 to measure the electrical potential between a driving ground electrode 806 and a data electrode 808. FIG8A illustrates an ideal or theoretical scenario in which no external noise is present, such as, for example, a completely shielded room in which the subject never moves. In this system, the measurement between data electrode 808 and ground electrode 806 indicates a signal from the EEG source (e.g., the subject's brain) free of noise artifacts.

In real-world environments (Figures 8B and 8C), external noise from electromagnetic (e.g., power lines) or electrostatic (e.g., walking) sources is present. Due to the low signal amplitude (e.g., approximately 1µV to approximately 100µV) and high electrode-skin impedance (e.g., greater than approximately 100kΩ) of EEG data, external noise sources play a significant role in the quality of EEG data. Electromagnetically induced noise can infiltrate EEG signals through multiple pathways. For example, electric fields can induce a displacement current 820 (I _EM2H , electromagnetic source to headset) that flows through associated capacitance 822 (C _EM2H , electromagnetic source to headset) into the headset 804's electrode leads, the electrode-skin interface, or various components of the EEG device (e.g., amplifier, power supply, etc.). Another source of electromagnetic noise is common-mode voltage on the subject's body. Displacement current 824 (I _EM2S , electromagnetic source to subject) flows through parasitic capacitance (C _EM2S , electromagnetic source to subject). Parasitic capacitance is the capacitance between any two adjacent conductors. The magnitude of this capacitance is determined by the proximity of the object to the power supply. The noise attributable to parasitic capacitance can be as high as 20V, for example, when an object grabs an insulated power line.

Another source of noise is static electricity. Friction creates a charge stored in capacitance 828 (C _ES2S , static electricity source to object) between the body and ground. For example, a third person with static electricity can induce static voltage and associated current 830 (I _ES2S , static electricity source to object) into the object when moving close to it. Displacement current 832 (I _ES2H , static electricity source to headset) is also injected, and capacitance 834 (C _ES2H , static electricity source to headset) is also induced into the headset 804 from external static noise.

External noise capacitively injects displacement currents 820 (I _EM2H ) and 832 (I _ES2H ) into the subject 802 or headset 804. This noise is converted by the impedance of the data electrode (Z _E ) and the impedance of the ground electrode (Z _G ) into additive noise, which can be orders of magnitude higher than the signal of interest. If the impedances are equal, this noise cancels out. In a low-impedance wet system ( FIG. 8B ), the conversion of displacement current into additive noise is minimized, allowing the noise to be kept below an acceptable level. However, typically, equal impedances of the data electrode (Z _E ) and the ground electrode (Z _G ) are not achievable.

In a system ( FIG8C ) including dry electrodes with a high-impedance electrode-skin interface (e.g., greater than approximately 100 kΩ), the impedance from the data electrode (Z _E ) is much greater than the impedance from the ground electrode (Z _G ). In this configuration, displacement currents 820 (I _EM2H ) and 832 (I _ES2H ) would typically flood the system with noise. However, the examples disclosed herein couple a conductive material with an electrode-skin impedance less than approximately 100 kΩ to the body of subject 802 . Example conductive materials include aluminum sheet and/or silver-coated nylon. The conductive material and subject 802 form a shield 840 that capacitively decouples the EEG device (e.g., head-mounted device 804 ) from the environment. Shield 840 is coupled to the subject via a shield electrode 842 with a low impedance (Z _S ). Shield 840 and shield electrode 848 effectively encapsulate head-mounted device 804 . Displacement currents 820 (I _EM2H ), 832 (I _ES2H ) generated by external noise sources, such as electromagnetic sources (e.g., power lines) or electrostatic noise sources (e.g., such as the subject walking or being near other people), flow through the path of least resistance (e.g., through the shielding electrode with low impedance Z _S ), and therefore, these displacement currents 820 (I _EM2H ), 832 (I _ES2H ) are not visible at the input of the EEG measurement device (e.g., the head-mounted device 804).

In some examples disclosed herein, a low impedance electrode-skin interface for ground and shield electrodes is achieved by introducing non-traditional locations for the ground electrode. For example, FIG9 is a schematic diagram of the top of the head showing example electrode and ground placement using the example head-mounted device of FIG1 or other example head-mounted devices disclosed herein. There are several abbreviations in the figure, including "N" for nasion, "F" for forehead (e.g., with respect to the frontal lobe of the brain, which is the area located at the front of each cerebral hemisphere), "A" for earlobe, "C" for center (e.g., with respect to the central area of the brain), "T" for temporal (e.g., with respect to the temporal lobe of the brain, which is located below and behind the frontal lobe at each cerebral hemisphere), "P" for parietal (e.g., with respect to the parietal lobe of the brain, which is located behind the frontal lobe), "O" for occipital (e.g., with respect to the occipital lobe of the brain, which is located at the back of the head), "I" for inion, and the subscript "z" for readings made along the midline of the brain.

As shown in Figure 9 , in this example, a driven ground electrode 151, which serves as a low-impedance dry electrode, and an electrode for shielding are placed on the forehead. A second data electrode 153 is placed at a typical ground location, such as the earlobe or mastoid process. Due to underlying muscle movement, the forehead is an unconventional location for ground electrode 151. The earlobe and mastoid process are relatively quiet areas of the scalp (e.g., relatively unaffected by electrical activity), lack hair (which reduces impedance at these locations), have low brainwave activity, and are less susceptible to artifacts from muscle movement, such as jaw muscle movement. Subtracting this additional data channel 153 from every other data channel (in the digital or analog domain) cancels out the adverse effects of the forehead ground electrode. This is called a reference, where the "0" potential of the system must be shifted (or referenced). The equation in Figure 9 shows that the effect of the forehead ground electrode 151 disappears when the data electrode 153 is subtracted from the data channel (e.g., data channel FC5). Thus, a low impedance electrode-skin connection (eg, less than about 100 kΩ) is achieved without the use of gel at the subject's forehead.

In addition to enabling systems with dry, low-impedance interfaces, these examples also enhance the common-mode rejection ratio (CMRR), which is where the device tends to reject input signals common to both input leads, since common signals (noise) will be subtractively attenuated. High CMRR is desirable in applications where the signal of interest is a small voltage superimposed on a potentially large voltage excursion.

The examples disclosed herein achieve high-quality EEG readings with low noise for a number of reasons. Some such examples are self-contained units, and therefore, the EEG platforms of these examples are electrically disconnected or decoupled from external power sources. Additionally or alternatively, the examples disclosed herein include a conductive layer that couples to the human body (e.g., the shield of FIG8C ) and encapsulates the EEG platform (e.g., the head-mounted device 804 of FIG8C ). Having low-impedance coupling between the conductive layer and the human body and high impedance to the EEG platform also capacitively disconnects the EEG platform from the environment, such that external sources cannot penetrate the EEG platform, and the capacitively coupled displacement current is undetectable or invisible at the input of the EEG platform, as disclosed above. Thus, the EEG platform is electrically isolated from external noise sources. The examples disclosed herein provide low electrode-skin impedance, such as, for example, as low as about 100 kΩ.

In other examples, additional shielding is provided. In some such examples, each electrode includes its own shield, the cables are shielded, and/or all electronics include further shielding. In some examples, the head-mounted device includes a conductive coating to enhance shielding. Additionally, in some examples, the head-mounted device includes a cover, such as, for example, silver-coated nylon, which also enhances shielding.

Furthermore, as disclosed herein, some example systems utilize reduced or no shielding because the electrodes collect data at such low impedance that the signal-to-noise ratio is high enough to enable processing of the data without additional shielding. Also, at such low impedance, noise sources become less relevant. The low capacitance of the components in some example systems reduces the need for additional shielding and thereby reduces system complexity. As disclosed herein, low impedance and low capacitance can be achieved, for example, using miniature signal lines in the flexible circuit board 150 and through the use of small electrodes held close to the head.

FIG10 is an enlarged view of an example adjustment mechanism 132 that can be incorporated into the first or second housing 126, 128. The illustrated example adjustment mechanism 132 includes a magnetic block or lock 152. Each elastic strip 118-124 is coupled to an attachment strip 154-160, respectively. Each attachment strip 154-160 includes a plurality of vertically arranged magnetic elements 162a-162f, 164a-164f, 166a-166f, and 168a-168f, respectively. Each attachment strip 154-160 is magnetically releasable and can be locked in multiple positions using the magnetic lock 152. In the illustrated example, there are multiple positions for coupling each attachment strip 154-160 to the magnetic lock 152. The magnetic elements 162a-162f, 164a-164f, 166a-166f, and 168a-168f on the attachment strips 154-160 allow the user to adjust the length of the elastic strips 118-124. For example, if the user wants to tighten the strap 102 for comfort and/or signal connection, the user releases the corresponding attachment strip 154 to engage with the magnetic lock 152, pulling the attachment strip 154 in a downward direction to another magnetic element 162a-162f. This pulls the elastic strip 118 and moves the spine 110 of the strap 102 closer to the user's head, thereby bringing the corresponding electrode into closer engagement with the user's scalp. The user then engages the magnetic strip 154 with the magnetic lock 152 to lock the strap 102 in the desired position. If the user desires to loosen the strap 102 for comfort, to adjust electrode placement and/or signal connection, and/or to remove the headset 100, the user can release the attachment strip 154 from the magnetic lock 152 and move the attachment strip 154 upward to loosen the elastic strip 118 and move the spine 110 of the strap 102 away from the user's head, thereby loosening or releasing the corresponding electrode from the user's scalp. The user then reengages the attachment strip 154 with the magnetic lock 152 to lock the strap 102 in the desired position. The same process can be repeated with any other straps. To completely remove the strap, the corresponding magnetic strip is removed from the attachment lock 152 and no longer engaged. Furthermore, in some examples, each elastic strip may have a magnetic ball or end point that engages one of multiple magnetic locks supported on the adjustment mechanism 132. In such examples, the strap can be adjusted to multiple positions defined by the position of the magnetic locks. In other examples, the elastic strip on the spine can be adjusted in any other manner.

Figures 11A, 11B, 11C, and 11D illustrate example electrodes that can be used with bands 102-108 of head-mounted device 100. Sensor (electrode) geometry and material influence the impedance characteristics of the signal connection. In some examples, the electrodes are formed from, for example, silver or silver chloride, which can provide, for example, approximately 10 MΩ impedance per square millimeter of contact surface. Additionally or alternatively, other materials with other impedance values per area can be used.

The example ring electrode 138a shown in FIG11A comprises a smoothly curved element. In the example of FIG11A , the end of the ring electrode 138a is molded into the body of the spine 110. However, in other examples, the electrode is removably coupled to the body of the spine 110. The electrode 138a of the illustrated example can be constructed from any conductive element. The electrode in the illustrated example is less than approximately 3 mm in diameter and greater than approximately 3 mm in length. This configuration allows the electrode to penetrate the user's hair and make contact with the scalp. The ring electrode 138a of the illustrated example is sufficiently resilient (e.g., springy) to flex and adjust when downward pressure is applied toward the head.

The example shown in FIG11B is a hook-shaped electrode 170. Similar to the example ring electrode 138a of FIG10 , the example hook-shaped electrode 170 of FIG11B is curved, allowing the electrode to penetrate the hair and rest against the user's scalp. FIG11C illustrates an example ball electrode 172. The example ball electrode 172 of FIG11C includes a shaft 174 and a ball 176. The illustrated example ball 176 can easily penetrate the hair and contact the user's scalp. In some examples, the ball electrode has an impedance of approximately 1.3 MΩ, the ball has a diameter of approximately 1.8 mm, and when pressed into tissue, the ball has an effective contact area of approximately 7.7 ^mm² . Increasing the size of the electrode increases the contact area and further reduces the impedance. For example, if a ball electrode with a diameter four times that of the example ball electrode described above were used, the contact area would be approximately 30 ^mm² , and the impedance would be reduced to approximately 300 kΩ.

FIG11D illustrates an example embodiment of a first ridge 110 equipped with a central array plate 178. In this example, there is a single array plate 178. However, in other examples, multiple array plates may be present. The bottom side of the first ridge 110 in the illustrated example includes a central array plate 178 to increase the number of electrodes contacting the scalp. The central array plate 178 in the illustrated example is embossed to include a plurality of pin-shaped individual electrodes. As the first elastic strip 118 (shown in FIG1 ) is tightened, the reflected pressure from the scalp forces the extensions 136 a - 136 t (shown in FIG5 ) of the first ridge 110 to flex outward, moving the bottom of the first ridge 110 closer to the scalp. As the bottom of the first ridge 110 approaches the scalp, some or all of the individual electrodes on the central array plate 178 penetrate the hair and contact the user's scalp. In the example shown in FIG11D , the central array plate includes approximately 256 individual electrodes or more. Each electrode has its own channel that is communicatively coupled to the processor via the PCB 150. With a large number of electrodes included on the example array board 178, a large number of electrodes disposed at extensions of the spines, and a large number of spines included in the head-mounted device 100, the example head-mounted device 100 collects signals from a very large number of channels. If, for example, the head-mounted device 100 includes ten spines, the number of channels can easily exceed 2,000 or 3,000 channels. This large number advantageously provides a greater amount of data from multiple areas of the brain, thereby creating a clearer and more comprehensive picture of brain activity. This large number of channels also provides oversampling, which enables virtual movement of the electrodes, as disclosed below.

In some examples, array plate 178 enables head mounted device 100 to include approximately 24 electrodes within a radius of approximately 1.5 cm. Electrodes within the same area may collect the same signal or substantially similar signals. In some examples, by combining two or more electrodes and/or by averaging two or more of the signals collected by the electrodes within the radius to use as a single value, the surface area of contact between the electrodes and the scalp is effectively increased, thereby improving the quality of the signals collected by the electrodes.

In some examples, the electrodes can be coupled in parallel to effectively increase the contact area of the electrodes by the number of electrodes coupled in parallel. Due to the parallel connection, if one electrode has high impedance or otherwise collects a poor signal, the effect of that electrode is smaller in the overall parallel configuration. The coupling of the electrodes reduces impedance and thermal noise effects. In some examples, the electrodes are fixedly coupled in parallel. In other examples, two or more electrodes are coupled via a switching circuit that can be selectively activated to short-circuit one or more electrodes, thereby effectively increasing the surface area contact between the electrodes and the tissue on the scalp. By short-circuiting one electrode and increasing the effective surface area of the second electrode, the impedance is reduced, which also enables the second electrode to effectively read higher frequency bands.

An example switching circuit 300 is shown in FIG12A . Example circuit 300 includes a plurality of electrodes: electrode A 302, electrode B 304, electrode C 306, and electrode D 308. In other examples, other numbers of electrodes may be present, including, for example, two, five, ten, fifty, and the like. These electrodes 302, 304, 306, 308 may represent a subset of a plurality of electrodes arranged within a small area, such as, for example, the area defined above by a radius of approximately 1.5 cm. In this example, each electrode 302, 304, 306, 308 is coupled to a corresponding analog-to-digital converter 310, 312, 314, 316. In other examples, electrodes 302, 304, 306, 308 may be coupled to the same analog-to-digital converter or to a different number of analog-to-digital converters. Furthermore, in some examples, electrodes 302, 304, 306, 308 may additionally or alternatively be coupled to other signal processing components, such as, for example, the components disclosed below by FIG36 and 37 .

Additionally, as shown in FIG12A , multiple electrodes, such as adjacent electrodes, can be coupled via switches. For example, electrode A 302 and electrode B 304 can be selectively electrically coupled via a first switch 318. Electrode B 304 and electrode C 306 can be selectively electrically coupled via a second switch 320. Furthermore, electrode C 306 and electrode D 308 can be selectively electrically coupled via a third switch 322. In other examples, additional and/or alternative electrodes can be coupled by switches 318, 320, 322 and/or additional switch(es). In some examples, one or more switches comprise transistors. Furthermore, in some examples, a controller controls each switch (e.g., controller 2 324 controls switch 322). In some examples, a single controller controls multiple switches (e.g., controller 1 326 controls switches 318 and 320). Switches 318, 320, 322 can be opened to electrically decouple the associated electrodes, or closed to electrically couple the associated electrodes. Electrically coupling two electrodes is a short circuit, which increases the contact area of the shorted electrodes, which, as mentioned above, reduces impedance and improves signal quality.

As mentioned above, another method for improving signal quality involves averaging the signals from two or more channels (e.g., electrodes). This averaging increases the signal-to-noise ratio by reducing both thermal noise and amplifier noise. An example graphical representation of signal averaging is shown in FIG12B . As shown, there are four signal channels (C1, C2, C3, C4) represented on a logarithmic scale. The signal from each channel consists of the EEG signal plus background noise. The first peak at 10 Hz indicates that the subject has closed their eyes. Consequently, the static noise from the subject's muscle contractions increases. Another increase in background noise is the second peak at 50 Hz, which is electromagnetic noise caused by power lines (e.g., the power line frequency in Europe). As shown in FIG12B , the average of the four channels (shown as the darkest line) has the lowest value on the y-axis and therefore carries the lowest amount of noise. As the frequency level increases, the noise reduction in the averaged signal increases, making the average more purified from noise than any individual component signal. This difference increases with increasing frequency. Thus, averaging the signal enables higher frequencies to be read with less noise interference, including, for example, frequencies up to about 100 Hz or even about 120 Hz.

Combination or hybrid systems can also be used that combine coupled electrodes and averaged signals. For example, a set of electrodes within a particular region can include subsets of electrodes electrically coupled via fixed parallel coupling or via selective switching. Each subset can provide a high-quality signal. Signals from two or more subsets can be averaged to further improve signal quality.

Furthermore, with a large number of electrodes, a user or automated analyzer can determine which electrodes are making optimal contact with the scalp and collecting the clearest signals by comparing the signal quality from each electrode. Nearby electrodes with lower signal quality can then be ignored. Furthermore, if an electrode has a relatively weak signal and a neighboring electrode has a stronger signal, the user or automated analyzer can utilize the stronger signal and ignore the weaker signal. This allows a user or machine (e.g., analyzer) to virtually move an electrode to a location with stronger signal collection without having to physically adjust any mechanical components (i.e., without having to physically adjust the position and orientation of the belt).

Figures 13A and 13B are cross-sectional views of example electrodes in contact with a user's scalp. Figure 13A shows a conventional electrode 180 that is unable to penetrate the user's hair. Consequently, conventional electrode 180 does not make sufficient physical contact with the user's scalp, which increases impedance and reduces signal quality. In the example of Figure 13B , electrode 182 is smaller and thinner than conventional electrode 180 and is sized to penetrate the hair and directly contact the user's scalp without any hair strands and/or hair follicles beneath electrode 182. Example electrode 182 also includes a cover 184 (e.g., a shield) to shield the electrode from electromagnetic interference (e.g., electromagnetic waves and noise) from the environment. The example cover 184 of Figure 13B is wide enough so that it cannot penetrate all of the hair on the user's head, thereby enhancing user comfort. However, in the illustrated example, electrode 182 is smaller and thinner than cover 184, allowing electrode 182 to penetrate the hair and contact the user's scalp. Consequently, electrode 180 is able to compress at least a portion of the stratum corneum. If the electrode is too thick, it will not be able to penetrate the user's hair (as shown in conventional electrode 180 in FIG13A ). If the electrode is too thin and protrudes too far, it may cause severe pain on the user's head. In the example shown in FIG13B , electrode 182 has a diameter d ₂ of approximately 0.5 mm, and cover 184 has an outer diameter d ₁ of approximately 1 mm. In the example of FIG13B , electrode 182 has a length l ₁ extending from cover 184 of approximately 0.2 mm to contact the user's scalp. Because electrode 182 can make direct contact with the scalp without interference from hair, the signal collected from electrode 182 experiences less impedance and noise than the signal collected from electrode 180 shown in FIG13A . Therefore, less shielding is required. Generally, the smaller the diameter of the electrode in contact with the scalp, the more discomfort the user may experience. However, if the distance between adjacent electrodes is reduced and/or the number of electrodes in a particular area is increased, the force or tension applied to the head-mounted device and therefore to the electrodes is shared between the electrodes, which increases user comfort and thus can offset the effect of small electrode points.

FIG14 is a circuit diagram 1400 of an example electrode-skin contact, which can represent, for example, Z _E of FIG8A-C . The coupling between the skin and the electrode is a layered conductive and capacitive structure, represented by a combination of parallel resistor and capacitor (RC) elements connected in series. Parallel capacitor C _d 1402 and resistor R _d 1404 represent the coupling impedance of the double layer at the skin-electrode interface, and parallel capacitor C _i 1406 and resistor R _i 1408 represent the input impedance of amplifier 1410. Resistor R _s 1412 represents the minimum series contact resistance, and voltage V _pol 1414 represents the DC polarization potential of the body.

Figures 15 and 16 illustrate alternative spines and electrodes constructed in accordance with the teachings of the present disclosure. Example strap 1500 has a spine 1502 and an elastic strip 1504 for tightening spine 1502 against the user's head. Ridge 1502 includes a plurality of individual electrode units 1506, each having a pair of leg-shaped electrodes 1508 and 1510 pivotally coupled to unit 1506 and projecting downwardly to aim electrodes 1508 and 1510 at the user's scalp.

FIG16 shows an exploded view of an example electrode unit 1506. The illustrated example electrode unit 1506 includes electrodes 1508 and 1510, each of which includes a shaft 1512, 1514 and a contact ball 1516, 1518, respectively. Each electrode 1508, 1510 also includes a mounting ring 1520, 1522, respectively. The mounting rings 1520, 1522 are disposed within an opening 1524 within a housing 1526. The housing 1526 includes a plate 1528 and sleeves 1530, 1532. The mounting rings 1520, 1522 of the electrodes 1508, 1510 fit between the sleeves 1530, 1532. In the illustrated example, the shafts 1512, 1514 extend below the plate 1528 and are angled outward from each other to contact the user's scalp. The electrodes 1508, 1510 are pivotally coupled to the housing 1526 via respective pins 1534, 1536 disposed through the sleeves 1530, 1532 and through respective holes in the mounting rings 1520, 1522. In the example of FIG16 , a spring 1538 is disposed between the mounting rings 1520, 1522 and the sleeves 1530, 1532. The spring 1538 includes tabs 1540, 1542. As the electrode unit 1506 is tightened downwardly toward the head, the electrodes 1508, 1510 rotate upwardly and flex. The ends of the shafts 1512, 1514 adjacent the mounting rings 1520, 1522 are pressed against the respective tabs 1540, 1542 of the spring 1538, which biases the electrodes 1508, 1510 downwardly back toward the head. When force is applied to the electrode unit 1506, the electrodes 1508, 1510 flex and maintain consistent downward pressure on the user's scalp. In the illustrated example, the spring 1538 comprises a non-conductive material to keep the signals collected from the first electrode 1508 separate from the signals collected from the second electrode 1510.

The electrode unit 1506 of the illustrated example allows the user to easily remove and replace each electrode. The top of plate 1528 includes a flexible PCB 1544, which is coupled to the processor for data processing by electrodes 1508, 1510 communication. PCB and electrodes 1508, 1510 can be coupled to the processor and/or any other analysis unit via a wired or wireless connection. As shown in Figure 15, the band 1500 of the illustrated example includes a plurality of individual electrode units 1506. Each electrode unit is hinged to an adjacent electrode unit so that the entire band 1500 can be bent around the user's head and placed against the user's head.

FIG17 is an exploded view of another example electrode unit 1700 constructed in accordance with the teachings of the present disclosure. In this example, electrodes 1702, 1704 are snap electrodes. Each electrode 1702, 1704 has a shaft 1706, 1708 and a contact ball 1710, 1712, respectively. The first electrode 1702 has a top hook member 1714 and a bottom hook member 1716. Similarly, the second electrode 1704 has a top hook member 1718 and a bottom hook member 1720. The example snap electrode unit 1700 of the illustrated example also includes a first connector 1722, a second connector 1724, a flexible plate 1726, a back plate 1728, and a front plate 1730. The first and second connectors 1722, 1724 each include a vertical portion 1732, 1734, respectively, and a horizontal portion 1736, 1738, respectively. Each of the first and second connectors 1722, 1724 further includes two holes 1740, 1742, 1744, 1746, respectively. The vertical portions 1732, 1734 are sized to fit within corresponding hook members in the top and bottom hook members 1714, 1716, 1718, 1720. The back panel 1728 includes a channel 1748 configured to receive the flexible plate 1726. The front panel 1730 also has a channel 1750 for receiving the flexible plate 1726. The back panel also includes four pegs 1752-1758. Two pegs 1752, 1754 are sized to engage the holes 1740, 1742 in the first connector 1722. The other two pegs 1756, 1758 are sized to engage the holes 1744, 1746 in the second connector 1724. The front plate 1730 of the illustrated example is operatively coupled to an opposite side of the back plate 1728 .

In operation, the snap electrode unit 1700 is pressed downward against the user's head. The downward force causes the shafts 1706, 1708 to pivot upward. The top hook members 1714, 1718 rotate inward onto the horizontal portions 1736, 1738, respectively, and thereby abut against the flexible plate 1726. The flexible plate 1726 provides a reflective force so that the electrodes 1702, 1704 maintain a consistent force against the user's scalp. The flexible plate 1726 also serves as a PCB to transmit any signals collected from the electrodes 1702, 1704 to a processor and/or other analysis unit as disclosed herein.

FIG18 illustrates another example electrode 1800 constructed in accordance with the teachings of the present disclosure. In the illustrated example, electrode 1800 includes a wire strip 1802 and a coil electrode 1804. In the example of FIG18 , coil electrode 1804 is a coil of wire wrapped around wire strip 1802 and positioned against the user's scalp. The individual coils of coil electrode 1804 penetrate the user's hair to establish contact with the scalp. If electrode 1804 is rotated, it will continue to maintain contact with the scalp, and any collected signals will not be lost.

Figures 19A and 19B illustrate another example electrode 1900 constructed in accordance with the teachings of the present disclosure. In the illustrated example, electrode 1900 includes a ribbon 1902 and a single curved electrode 1904. Figure 19B is a cross-sectional view of electrode 1900 of Figure 19A. The illustrated example single curved electrode 1904 has two spherical heads 1906, 1908 at the ends of electrode 1904. Single curved electrode 1904 is curved on ribbon 1902 so that both ends point downward and both spherical heads 1906, 1908 can contact the user's scalp. As ribbon 1902 is stretched or tightened, the electrode coupled thereto is also stretched, and the center portion of electrode 1904 moves closer to the scalp to provide additional pressure to the spherical heads 1906, 1908 against the scalp.

FIG20 illustrates a mold 2000 that can be used to manufacture the spines shown and described in FIG1-7. In the illustrated example, mold 2000 includes a mold body 2002 and a mold cavity 2004. Mold cavity 2004 defines the shape of a flat spine. In the exemplary manufacturing process, the PCB and electrodes are first placed within the mold, and then liquid plastic or resin is injected into cavity 2004 to form the spine body. After the molding process, the spine is removed and formed to curve each extension downward.

FIG21 shows a plurality of ridges 2100, 2102, 2104 immediately after molding in the process described in conjunction with FIG20 and before ridge shaping. In the example of FIG21, the ridges 2100, 2102, 2104 include a plurality of electrodes 2106, 2108, 2110 extending from the ridges 2100, 2102, 2104. The ball electrodes 2106, 2108, 2110 can be bent downward. In this example, the end of each ridge 2100, 2102, 2104 includes a pin port 2112, 2114, 2116 for coupling the ridges 2100, 2102, 2104 to a processing unit of a head-mounted device.

Figures 22A-22J are perspective views of a user's head identifying the optimal area for electrode contact. As shown in these figures, there are multiple electrode sites, including, for example, 20 sites related to the international 10-20 system. These sites provide coverage of all lobes of the brain, including the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. These sites are EEG electrode sites that are accepted for clinically effective EEG. The sites shown in Figures 22A-22J are selected to provide wide coverage and avoid sites with excessive muscle activity. In an example head-mounted device with eighty channels, the twenty sites of the international 10-20 system are covered as additional sites on the muscles. For example, the eighty channel system provides prominent coverage of non-muscle contamination sites, as well as coverage of the muscle sites included in the standard clinical EEG system.

Figure 22J illustrates an example head-mounted device with five straps 2202-2210 positioned on a user's head for readings. Each strap 2202-2210 is adjustable and can be positioned along a specific path to optimize electrode placement. The example arrangement in Figure 22J bisects the head into left and right sections by forming a line from the nasion (between the eyes) to the inion (at the back of the head). A second line bisects the head along the line from the left ear canal to the right ear canal. Each of these lines further divides the head at intervals of 10% and 20% of their distance. In the illustrated example, the first elongated strap 2202 is positioned above the subject's nasion at approximately 10% of the distance between the subject's nasion and the inion, measured at the center of the subject's head. The second elongated strap 2204 is positioned above the nasion at approximately 30% of the distance from the inion. The third elongated strap 2206 is positioned approximately halfway between the nasion and the inion. The fourth elongated band 2208 is positioned past the halfway point, for example, closer to the inion than the nasion but more than 30% of the distance from the inion. The fifth elongated band 2210 is positioned approximately 30% of the distance above the inion. This arrangement can optimize coverage of the entire head. In other examples, additional bands are included in positions between the five illustrated bands. Furthermore, in other examples, the bands 2202-2210 can be positioned at any other desired degree of rotation, depending on the desired reading and/or the quality of the electrical contact between the electrodes and the scalp.

FIG23 illustrates an alternative example head-mounted device 2300 for measuring electrical activity at the scalp, constructed in accordance with the teachings of the present disclosure. This example head-mounted device 2300 includes a main headband 2302 that curves over the top of a user's head. Multiple support straps with individual electrodes extend from headband 2302 in multiple directions to position the electrodes at various locations on the user's head. Head-mounted device 2300 includes a left hub 2304 and a right hub 2306, both of which are rotatably and removably coupled to the ends of headband 2302. In the illustrated example, the left hub 2304 includes seven support straps 2308-2320. The right hub 2306 of the illustrated example also includes seven support straps 2322-2334. However, in other examples, a different number of support straps may be used to increase, decrease, and/or otherwise adjust the number and/or location of electrode placement. In this example, each support strap 2308-2334 has a set length and two ends that are fixedly and flexibly coupled to the left and right hubs 2304 and 2306, respectively. In some examples, one or more of the lengths of the support straps 2308-2334 are adjustable. The headband 2302 also includes front support straps 2336-2344 and rear straps 2346-2348. In this example, each support strap 2336-2348 has a set length and is fixedly and flexibly attached to the headband 2302 at one end. Furthermore, in some examples, one or more of the lengths of the support straps 2336-2344 are adjustable. The distal ends of all support straps 2308-2348 are operatively coupled to corresponding electrode housings 2250a-2250u. Each housing 2250a-2250u houses a separate electrode 2352a-2352u. In some examples, one or more electrode housings 2250a-2250u support multiple electrodes. In the illustrated example, different straps in the support bands 2308-2348 have different lengths to position corresponding electrodes 2352a-2352u at different locations on the scalp. These locations can be selected to optimize the detection of electrical activity in the brain. The support bands 2308-2348 are slightly curved inward to apply sufficient force on the user's head to slightly press the corresponding electrodes against the scalp, thereby reducing noise and increasing the signal-to-noise ratio to enhance signal quality. In addition, the support bands 2308-2348 in the illustrated example include flexible plastic so that each support band 2308-2348 can flex when placed on the user's head and adjust accordingly to different head sizes, as well as apply constant and/or sufficient force to the scalp for reading electrical signals from the brain. In the example shown in Figure 23, the head-mounted device 2300 has 21 support bands and 21 electrodes. However, in other examples, the head-mounted device includes more or fewer support straps and/or may include more than one electrode per support strap.

23 , the head-mounted device 2300 can be coupled to a base 2354 for storing the head-mounted device 2300 when not in use, for charging the head-mounted device 2300, and/or for data transmission, as disclosed in more detail below. The base 2354 includes a support shaft 2356 extending generally vertically for holding the head-mounted device 2300 on a support surface such as a table, stool, or shelf. The base 2354 also includes a bottom plate 2358 for supporting the base 2354 in an upright position. In some examples, the base 2354 transmits data to a data analyzer via a wired connection. In other examples, the base 2354 transmits data wirelessly.

FIG24 is a bottom view of the example head-mounted device 2300 of FIG23 . The headband 2302 has a micro-USB port 2386 on the bottom for battery charging and data transfer. The head-mounted device 2300 includes a battery within the central headband 2302 and/or within a housing, such as, for example, a housing located near the side of the head (see, for example, housings 3010 , 3012 disclosed below in conjunction with FIG30 , which can be incorporated into the example head-mounted device 2300 of FIG23 ). As seen in FIG25 , the base shaft 2356 of the base 2354 includes a male micro-USB connector 2388 that can be inserted into the micro-USB port 2386 for charging the head-mounted device 2300 and/or transferring data from a processor based on the head-mounted device to a computer or database for further processing. In other examples, any other suitable electrical and/or communication coupling can be used, including, for example, other types of physical ports and/or wireless couplings.

Figures 26-29 are different views of an example head-mounted device 2300. As can be seen in Figures 26 and 27, the left and right hubs 2304 and 2306 are rotatably and pivotally coupled to the ends of the headband 2302. The left hub 2304 has an adjustment ball 2360 that fits within a left socket 2362 on the inside of the headband 2302. The adjustment ball 2360 and the left socket 2362 (i.e., a ball-and-socket joint) allow the hub 2304 to rotate and pivot in any desired direction to position the support straps 2308-2320 at the desired location on the left side of the user's head. The right hub 2306 also has an adjustment ball 2364 that is designed to fit within a right socket 2366 on the headband 2302. Thus, the right hub 2306 is also coupled to the headband via a ball-and-socket joint, allowing the hub 2304 to rotate and pivot to any desired position. 28 shows the headband 2302 bent slightly to the rear so that the headset 2300 is supported at the crown of the head, with the left and right hubs 2304, 2306 positioned near the left and right ears, respectively.

Figure 29 is a bottom view of the headset 2300 and illustrates that the headset 2300 includes a cushion 2368, which provides comfort to the user and can also be used to provide stability to the headset 2300, allowing the headset 2300 to maintain its position as the user moves their head. Increasing the stability of the headset 2300 also reduces any noise that may be generated by friction caused by the movement of the electrodes along the user's scalp. Additionally, the cushion 2368 can also serve as a housing that encloses electrical components such as a processor, which can include hardware, firmware, and/or software for processing signals from the electrodes, converting EEG data from analog to digital, amplifying the EEG data, removing noise from the data, analyzing the data, and/or transmitting the data to a computer or other network. The headset 2300 includes a printed circuit board 2370, which is disposed within the headband 2302 and support straps 2308-2344, to communicatively couple the electrodes 2352a-2352u to the processor for processing. Additionally, in some examples, housing 2368 may enclose a power source such as, for example, one or more batteries.

FIG30 illustrates an exploded view of example layers of an example head-mounted device 3000. Although alternative shapes are shown in FIG30 , the layering concept illustrated in FIG30 can be used with any suitable head-mounted device structure, including, for example, the head-mounted device 100 of FIG1 , the head-mounted device 1500 of FIG15 , the head-mounted device created in the mold 2000 of FIG20 , the head-mounted device 2300 of FIG23 , and/or other suitable head-mounted devices. A first layer 3002 comprises a plastic and/or metal shell layer. This first layer 3002 provides the required tension and shape for the head-mounted device 3000, as well as the flexibility required to adjust the head-mounted device and apply sufficient force at each electrode to optimize signal collection. The dimensions (e.g., width) of each arm in the layer are specifically designed for a specific tension (e.g., to optimize performance). A second layer 3004 is a flexible circuit board that transmits data collected at each electrode to the electronics/processor. The head-mounted device 3000 includes a third layer 3006 and a fourth layer 3008 at each end. Third layer 3006 corresponds to the material of first layer 3002, and fourth layer 3008 corresponds to the material of second layer 3004. First layer 3002 and third layer 3006 provide shielding for signals as they propagate along second layer 3004 and fourth layer 3008. Furthermore, the materials used can be selected to enhance shielding for the flexible PCB and electromagnetic interference shielding for the example system. Furthermore, the PCBs of second layer 3004 and fourth layer 3008 are flexible and thin, and include thin wiring with low impedance and low capacitance, which reduces losses during signal propagation.

The head-mounted device 3000 also includes a first housing 3010 and a second housing 3012. Examples of the first and second housings are shown in more detail in FIG. 31 . Each housing includes a cover 3014 and a support ring 3016. Electronic components and a processor are supported in one or more of the housings 3010, 3012. Additionally or alternatively, in some examples, an adjustment mechanism (such as, for example, the adjustment mechanism of FIG. 9 ) is supported by one or more of the housings. Although an elliptical shape is shown in FIG. 30 and 31 , any suitable shape may be used for the housings.

Figures 32A and 32B illustrate top and bottom perspective views of an example snap electrode unit 2372. The snap electrode unit 2372 includes a backplate 2374 and an electrode layer 2376. The electrode layer 2376 can include silver-coated electrodes or electrodes coated or made with any suitable conductor. The backplate 2374 has a shaft 2378 that extends through the PCB 2370 and support strap 2390 into the back side of the electrode 2376, thereby coupling the electrode 2376 to the PCB 2370 and support strap 2390. The electrode can be easily assembled with the backplate or removed from the backplate to facilitate replacement of the electrode. Figures 32C and 32D illustrate a snap electrode unit 2372 with an alternative contact electrode 2380.

FIG33 is an enlarged view of the example electrode housing 2350 and example electrode unit 2352 of FIG23 . As shown in FIG33 , the housing encloses the backplate 2374 (shown in FIG32A-32D ), but the shaft 2378 extends from the housing to receive the electrode. In the illustrated example, the electrode unit 2352 includes an alternative elongated electrode 2382. In other examples, the electrode has any other shape or size suitable for contacting the user's scalp to receive an electrical signal.

FIG34 is a perspective view of an example mesh array headset 3400. The mesh array headset 3400 includes a plurality of elastic bands 3402a-3402m arranged in a zigzag or cross pattern. Electrodes 3404a-3404t are positioned at each intersection of the elastic bands 3402a-3402m. The plurality of elastic bands 3402a-3402g converge at the rear side of the mesh array headset 3400 and are coupled to an adjustment knob 3406. As the adjustment knob 3406 is turned, each elastic band 3402a-3402m (and other unnumbered ones) is tightened, and the electrodes 3404a-3404c (and other unnumbered ones) are forced downward onto the user's scalp. The adjustment knob 3406 allows the mesh array headset 3400 to be adjustably used on a variety of heads of different sizes. As shown in Figure 35, the adjustment knob 3406 can be rotated to roll up each elastic band 3402a-3402g and thereby tighten the mesh array head-mounted device 3400 onto the user's head. The mesh array head-mounted device 3400 enhances the fit of the electrodes on heads of different shapes and creates a lightweight and portable head-mounted device.

FIG36 is a block diagram of an example processing system 3600 for use with any of the head-mounted devices disclosed herein. Example system 3600 includes a plurality of electrodes 3602. Electrodes 3602 are coupled to, for example, a head-mounted device that is worn on a subject's head. In some examples, the head-mounted device includes a plurality of elongated straps that extend between a first housing positioned near a first ear of the subject and a second housing positioned near a second ear of the subject. In some examples, one or more elongated straps are rotatably and/or removably coupled to each of the first and second housings to enable electrodes 3602 to be moved to different locations on the head and/or removed from the head-mounted device. The head-mounted device can include multiple electrode channels to enable multiple (e.g., 2,000 or more) electrodes to be included in example system 3600. Additionally, in some examples, the pressure applied by each electrode on the head can be adjusted by adjusting an elastic band or strap associated with each elongated strap.

The electrodes can have any suitable shape, such as, for example, a ring, a ball, a hook, and/or at least a portion of an array. Electrode 3602 can include one or more properties of any electrode disclosed in this patent. In addition, different types of electrodes can be included in system 3600. Furthermore, in some examples, electrode 3602 and the elongated strip to which electrode 3602 is coupled have a protective covering, such as, for example, nylon and/or silver mesh. In some examples, the covering is a stretchable silver-coated nylon mesh. The covering provides additional shielding and protection. Additionally, electrode 3602, including the covering, is machine washable.

The example electrode 3602 may also be adjustably mechanically coupled to the first housing, such as, for example, via an elongated strap, in which an adjustable locking mechanism is supported to releasably hold the elongated strap, and thus the electrode 3602, in one or more positions. Example locking mechanisms include the magnetic locks disclosed above.

The electrodes 3602 are also communicatively coupled to a second housing (e.g., the second housing 128 of the head mounted device 100 shown in FIG. 1 ) supporting an electrical processing unit 3604 via a communication line 3606, which can be, for example, a wired or wireless communication link, including, for example, the PCB communication channels disclosed above. The example processing unit 3604 includes an analog-to-digital converter 3608, a signal conditioner 3610, a database 3612, an analyzer 3614, and a transmitter 3616.

Analog-to-digital converter 3608 converts the analog signal received at electrode 3602 into a digital signal. In some examples, analog-to-digital converter 3608 is located in processing unit 3604 at one of the housings of the head-mounted device. In other examples, analog-to-digital converter 3608 includes multiple A-to-D converters located to serve individual electrodes or groups of electrodes, converting the signal as close to the source as possible, which can further reduce interference.

The illustrated example signal conditioner 3610 prepares the collected signal so that the data is in a more usable form. For example, the signal conditioner 3610 may include an amplifier for amplifying the signal to a more detectable level. In addition, the signal conditioner 3610 may include a filter for removing noise from the signal. The filter may also function as a bandpass filter to pass through one or more frequency bands and/or manipulate the selected frequency bands according to the desired processing and/or analysis. For example, in an analysis that only studies alpha waves, the signal conditioner may be programmed to present only those frequencies between approximately 7.5 Hz and approximately 13 Hz. In some examples, each electrode 3602 may include a signal conditioner at or near the electrode 3602. The example signal conditioner 3610 may include hardware and/or software for performing the signal conditioning method. In some examples, the signal conditioner includes a detrending unit for compensating for electrode polarization, where there is a slow movement of the voltage signal that is not related to brain wave activity caused by electrode polarization. The example processing unit 3604 also provides signal processing, which may include hardware and/or software for performing fast Fourier transform (FFT) measurements, coherence measurements, and/or customized adaptive filtering.

Analyzer 3614 is used to analyze data collected from electrodes 3602 and processed by analog-to-digital converter 3608 and signal conditioner 3610 according to one or more analysis protocols in accordance with a desired study. For example, according to some studies, analyzer 3614 may process the data to determine one or more of a subject's mental state, physiological state, attention, empathy or memory, emotional engagement, and/or other suitable characteristics of the subject.

Transmitter 3616 transmits data at any processing stage and/or analysis results from analyzer 3614 to output 3618. Output 3618 can be a handheld device, an alarm, a display screen on the headset, a remote server, a remote computer, and/or any other suitable output. Data transmission can be implemented via Bluetooth transmission, Wi-Fi transmission, ZiGBee transmission, and/or proprietary encryption before transmission. In the illustrated example, database 3612 stores all data collection streams. These streams can be buffered for onboard streaming (i.e., at the headset) or stored for periodic or aperiodic upload, such as during periods of low activity.

Processing unit 3604 components 3608-3616 are communicatively coupled to the other components of example system 3600 via communication link 3620. Communication link 3620 can be any type of wired connection (e.g., a data bus, a USB connection, etc.) or wireless connection mechanism (e.g., radio frequency, infrared, etc.) using any past, present, or future communication protocol (e.g., Bluetooth, USB 2.0, USB 3.0, etc.). Furthermore, the components of example system 3600 can be integrated into one device or distributed across two or more devices.

While an example manner of implementing system 3600 has been illustrated in FIG. 36 , one or more of the elements, processes, and/or devices illustrated in FIG. 36 may be combined, divided, rearranged, omitted, eliminated, and/or implemented in any other manner. Furthermore, the example signal conditioner 3610, example A/D converter 3608, example database 3612, example transmitter 3616, example analyzer 3614, example output 3618, and/or more generally the example system 3600 of FIG. 36 may be implemented using hardware, software, firmware, and/or any combination of hardware, software, and/or firmware. Thus, for example, the example signal conditioner 3610, example A/D converter 3608, example database 3612, example transmitter 3616, example analyzer 3614, example output 3618, and/or more generally the example system 3600 of FIG. 36 may be implemented using one or more circuits, programmable processors, application specific integrated circuits (ASICs), programmable logic devices (PLDs), and/or field programmable logic devices (FPLDs), among others. Where any apparatus or system claims of this patent are to be construed as covering purely software and/or firmware implementations, at least one of the example signal conditioner 3610, the example A/D converter 3608, or the example database 3612 is hereby expressly defined as comprising hardware and/or tangible computer-readable media such as memory, DVD, CD, etc. storing the software and/or firmware. Further, the example system 3600 of FIG36 may include one or more elements, processes, and/or devices in addition to or in place of those illustrated in FIG36, and/or may include more than one of any or all of the illustrated elements, processes, and devices.

FIG37 illustrates another example system 3700 that can be implemented, for example, by one or more of the example head-mounted devices 100, 2300, 3400 shown in FIG1, 23, and 34. The example system 3700 of FIG37 can be used to enhance signal strength by, for example, short-circuiting one or more electrodes using, for example, the example circuit 300 of FIG12A to effectively increase the surface area of the electrodes. Increasing the surface area reduces impedance and improves the signal-to-noise ratio of data collected at the electrodes. Additionally, the example system 3700 can be used to virtually move the electrodes by selecting one or more input channels to select more efficient electrode positions occupied by electrodes that achieve higher-quality and lower-noise signals. These electrodes can, for example, be electrodes that have optimal or near-optimal contact with the scalp. The system 3700 enables a user or operator to discard electrodes that are inoperable, misoperating, or insufficiently coupled to the scalp and/or the rest of the head-mounted device.

The example system 3700 in FIG37 includes any number of input channels (e.g., a first input channel 3702, a second input channel 3704, a third input channel 3706, a fourth input channel 3708, ..., an nth input channel 3710). For example, as disclosed above, one or more head-mounted devices disclosed herein may include 2,000 or more input channels. In this example, each of the input channels 3702-3710 is associated with an electrode. In other examples, one or more of the input channels 3702-3710 may be associated with other types of sensor(s), such as, for example, an eye tracker, a galvanic skin response sensor, a respiration rate sensor, a thermometer, a sphygmomanometer for measuring blood pressure, an fMRI sensor, and/or any other suitable type of sensor. Such sensor(s) may be freely added or removed. Some sensor(s) may be added to the head-mounted device itself, and other sensor(s) may be coupled to an arm, chest, or other body part and communicatively coupled to the head-mounted device.

The example system 3700 of FIG37 includes an analyzer 3712. In the illustrated example, the analyzer 3712 is implemented by a programmed processor. The example analyzer 1712 of FIG37 includes an evaluator 3714, a regulator 3716, and a selector 3718. In some examples, one or more components 3714-3718 of the analyzer 3712 are incorporated into a housing, such as, for example, the second housing 128 of the head-mounted device 100 shown in FIG1-3. In other examples, one or more components 3714-3718 of the analyzer 3712 are incorporated into a handheld device, a local computer, a remote server, or other suitable device. The evaluator 3714 evaluates properties of the input signal, such as, for example, intensity, amplitude, signal-to-noise ratio, duration, stability, and/or other suitable signal characteristics that indicate data integrity and/or the quality of the connection between the head-mounted device and the scalp. Example methods for determining what signals are acceptable include, for example: comparing one or more aspects of the signal from a given electrode (e.g., its amplitude, frequency, etc.) to one or more of an absolute threshold, a spectral threshold, a slope rate threshold, a low activity (flat) threshold; and/or performing a proximity correlation between the signal from the given electrode and signals from one or more other electrodes near the given electrode.

The example conditioner 3716 of the illustrated example amplifies and/or filters the signal to improve signal quality. If the conditioner 3716 enhances the signal quality to an acceptable level so that the signal can be used, the evaluator 3714 of the illustrated example determines that the data integrity from the associated electrode is acceptable and the data does not need to be discarded, and/or determines that the data from the electrode needs to be ignored or discarded.

The selector 3718 of the illustrated example selects which input channels to ignore, use, and/or combine (e.g., average) to improve (e.g., optimize) the overall input based on the determination of the evaluator 3714. The plurality of input channels 3702-3710 are communicatively coupled to the analyzer 3712 and corresponding components 3714-3718 via a communication link 3720 (e.g., any wired or wireless communication link).

In the example system 3700 shown in FIG37 , the example evaluator 3714 determines which of the input channels 3702-3710 (e.g., electrodes) collect the best, most useful, and/or most accurate data. Based on this determination, the example selector 3718 identifies which electrodes/input channels are most effective (e.g., for optimal EEG readings) and which electrodes/input channels should be ignored to improve readings. Ignoring an electrode/communication can include disabling the channel (e.g., via a switching circuit) and/or ignoring the data collected by it. Disabling an electrode effectively increases the surface area contact between one or more electrodes adjacent to the disabled electrode and tissue on the scalp. Disabling an electrode/channel can be referred to as short-circuiting the electrode. By short-circuiting an input channel (e.g., effectively increasing the effective surface area of another electrode adjacent to the input channel), the overall impedance of the channel is reduced and signal quality is improved. Lower impedance and better signal-to-noise ratio enable the example system 3700 of FIG37 to read higher frequency bands. The selection of which electrodes are candidates for short-circuiting is based on regional coverage and data quality. For example, if there is increased noise in multiple electrodes within a small area of proximity, some or all of these electrodes can be short-circuited to improve the signal-to-noise ratio. Furthermore, with a large number of input channels, selector 3718 can determine which electrodes make the best contact with the scalp and collect the clearest signal. Switching circuits 300 ( FIG. 12A ) and 3722 ( FIG. 37 ) can be utilized to ignore and/or short-circuit other nearby electrodes. Furthermore, if an input channel provides a relatively weak signal and an adjacent input channel provides a stronger signal, selector 3718 can deselect the channel with the weaker signal to emphasize the input channel with the stronger signal. Deselecting a signal (e.g., disabling it via switching circuit 3722 ) and relying on data collected by an adjacent electrode can be considered as moving the functionality of the deselected electrode to the adjacent electrode. Thus, the example system 3700 of FIG. 37 can virtually move electrodes to a position where they collect stronger signals without having to physically adjust any mechanical components (i.e., without physically removing the electrodes).

While an example manner of implementing system 3700 has been illustrated in FIG. 37 , one or more of the elements, processes, and/or devices illustrated in FIG. 37 may be combined, divided, rearranged, omitted, eliminated, and/or implemented in any other manner. Furthermore, the example analyzer 3712, example evaluator 3714, example regulator 3716, example selector 3718, example switching circuitry, and/or more generally, the example system 3700 of FIG. 37 may be implemented using hardware, software, firmware, and/or any combination of hardware, software, and/or firmware. Thus, for example, the example analyzer 3712, example evaluator 3714, example regulator 3716, example selector 3718, example switching circuitry 3720 of FIG. 37 , and/or more generally, the example system 3700 of FIG. 37 may be implemented using one or more circuits, programmable processors, application specific integrated circuits (ASICs), programmable logic devices (PLDs), and/or field programmable logic devices (FPLDs), among others. Where any apparatus or system claims of this patent are to be construed as covering purely software and/or firmware implementations, at least one of the example analyzer 3712, the example evaluator 3714, the example adjuster 3716, the example selector 3718, or the example switch circuit 3720 is hereby expressly defined as comprising hardware and/or tangible computer-readable media such as memory, DVD, CD, etc. storing the software and/or firmware. Further, the example system 3700 of FIG37 may include one or more elements, processes, and/or devices in addition to or in place of those illustrated in FIG37, and/or may include more than one of any or all of the illustrated elements, processes, and devices.

FIG38 illustrates an example system 3800 including a head-mounted device 3812, which represents one or more example head-mounted devices and/or systems described herein, such as, for example, head-mounted device 100 of FIG1 , head-mounted device 2300 of FIG23 , head-mounted device 3400 of FIG34 , system 3600 of FIG36 , system 3700 of FIG37 , and/or system 3900 of FIG39 with additional physiological sensor(s) (disclosed below). Example system 3800 can be used for at-home patient monitoring, treatment, and/or diagnosis of medical conditions to detect life-threatening situations, determine patient compliance with prescribed medical regimens, and/or other suitable applications. Currently, patients must visit a hospital for neurological monitoring. This inherently increases the risk of exposure to hospital-acquired pathogens (such as, for example, acquired bacterial infections). However, in a hospital setting, skilled personnel are available to monitor data, detect issues, and alert medical staff. However, there is no guarantee that data of interest defining neurological status will not be lost. In a home environment, if there is a medical problem and/or emergency, the example head-mounted device and/or system disclosed herein automatically monitors data, detects problems, and alerts the patient, emergency call center, caregiver, doctor, and/or local hospital. For example, a patient may have signs (warnings) of an attack at home and do not have time to go to the hospital for monitoring. A self-applied, home EEG monitoring system including the example head-mounted device disclosed herein enables the capture of this information, which is critical for proper care. In addition, the self-applied system disclosed herein enables patients to transmit data, (one or more) questions, (one or more) communications, and/or other information to medical care professionals when they feel that something is not right with their physiology (including, for example, underperformance in cognitive areas). In addition, hospitals have technicians to monitor data quality and equipment functionality. The examples disclosed herein automatically perform these functions, thereby achieving cost savings and reducing the possibility of human error.

Furthermore, the headset and/or system generates data that can be used in conjunction with telecommunications and/or other information technologies to provide clinical care from a remote location. For example, a patient can be examined and/or monitored by sending sensor data to a remote doctor or physician. In some examples, EKG data can be monitored, such as for 24-hour home monitoring of a patient with cardiac arrhythmia. In such an example, an EKG sensor is attached to the patient at home, whereby the system is coupled to a telephone line, the internet, or other communication link. The EKG readings are sent directly to the patient's cardiologist (and/or technician, nurse, etc.) via the communication link. The example system 3800 of FIG. 38 can be used for a wide variety of patients with a wide variety of symptoms, including: cardiac arrhythmia, seizures, stroke, small vessel disease, dementia, memory loss, Alzheimer's disease, glucose monitoring, blood pressure, hypertonia, cognitive decline, depression, and/or other symptoms. Other physiological conditions, psychiatric conditions, disease progression, efficacy of disease interventions, and/or developmental disorders may also be monitored using system 3800, such as, for example, bipolar disorder, schizophrenia, attention deficit hyperactivity disorder (ADHD), and/or autism.

With respect to EEG data and head-mounted devices for collecting data, conventional systems have been uncomfortable to wear, require messy gels, are expensive to manufacture, and/or require extensive training for use. The example head-mounted devices 100, 2300, 3400, 3812 disclosed herein are useful (e.g., optimal) for at-home patient monitoring because such disclosed head-mounted devices 100, 2300, 3400, 3812 are comfortable to wear, easy to operate, provide effective electrode-to-tissue contact, include a large number of electrodes, and/or are adjustable to accommodate heads of different sizes. In some examples, data from the example head-mounted devices 100, 2300, 3400, 3812 is processed at the head-mounted device and transmitted to an off-site monitoring station for analysis by medical personnel (e.g., a doctor or physician). In some examples, data storage occurs at the head-mounted device, at a remote data center, or a combination thereof.

The example head mounted devices 100, 2300, 3400, 3812 disclosed herein may be combined with (one or more) additional biometric, neural and/or physiological systems to monitor, examine, treat and/or diagnose a variety of medical conditions, including physiological conditions and/or mental conditions. In the example system 3800, data from the EEG system 3802 is combined and aggregated with data from an EKG system 3804, a glucose monitoring system 3806, an EOG system 3808, a facial monitoring system 3809, and/or any other plug-in/plug-and-play system 3810 (e.g., installable or coupleable programs and/or devices for adding additional functionality), such as, for example, eye-tracking sensor(s) (e.g., eye-tracking sensor 3910 of FIG. 39 ), galvanic skin response (GSR) signal(s), EMG signal(s), camera(s), infrared sensor(s), interaction speed detector(s), touch sensor(s), and/or any other sensor capable of outputting physiological and/or neural data to a head-mounted device 3812 or directly to an off-site monitoring station. Additionally, in some examples, the example facial monitoring system 3809 includes a camera with full face and/or half face coverage to implement facial expression coding (FACS), which allows classification of facial expressions. In some examples, the example facial monitoring system 3809 includes a camera coupled to a telescopic arm.

In the illustrated example, the head-mounted device 3812 includes an EEG system 3802, a local analyzer 3814 (which can be incorporated into the second housing 128 of the head-mounted device 100 of FIG. 1 , for example), an output 3816, and a manual input 3818. In the illustrated example, the subsystems 3802-3810 are communicatively coupled to the head-mounted device 3812 and, therefore, to the local analyzer 3814 via a communication link 3820, which can include hardwired and/or wireless technology. Additionally, in some examples, one or more of the subsystems 3802-3810 can be incorporated into the head-mounted device itself (e.g., the EOG system 3808 and/or the facial monitoring system 3809).

Each signal from the different subsystems 3802-3810 represents an input. Each input can be filtered, conditioned, and/or processed to form an output representing one or more attributes or characteristics of the patient's condition. In the illustrated example, the EKG system 3804 is coupled to the patient's chest, and the EKG data is wirelessly transmitted to an EEG headset 3812. The EKG data is processed by a local analyzer 3814 and transmitted to a remote facility 3822 for use in treating, diagnosing, and/or monitoring the patient. The remote location can be, for example, a doctor's office, hospital, clinic, laboratory, archive, research facility, and/or any other diagnostic facility. The local analyzer 3814 can be communicatively coupled to the remote facility via a communication channel 3824 such as a public telephone line, landline, internet connection, radio waves, and/or any other communication technology capable of transmitting signals. In the example shown in FIG. 38 , the local analyzer 3814 includes a clock 3826 and a database 3828. The clock 3826 of the illustrated example timestamps data for use, for example, in monitoring the progress of a health condition or treatment and/or generating medical records.The database 3828 of the illustrated example is used for local storage.

In the example shown in FIG38 , local analyzer 3814 creates output 3816. Output 3816 can be, for example, light, sound, a display, and/or any other output, which can be used, for example, to alert a patient to seek medical attention, take a dose of medication, start an activity, stop an activity, eat, and/or any other suitable warning and/or command. In some examples, output 3816 is operatively coupled to an automated delivery system to automatically deliver medication to the patient in response to specific readings from system 3800. For example, diabetics often require continuous glucose and blood pressure monitoring. Example system 3800 can monitor insulin levels based on measured physiological characteristics and automatically deliver insulin to the patient. In the example shown, output 3816 (e.g., light, speaker, display, automated delivery system) is incorporated into headset 3812. In other examples, output 3816 can be separate from headset 3812, and the headset can communicate with output 3816 via a wired or wireless communication link as disclosed herein.

Example system 3800 may be used to detect and/or treat psychiatric conditions such as depression. For example, a patient's brain waves may be monitored by head-mounted device 3812 via EEG subsystem 3802. If local analyzer 3814 detects that the patient is becoming more depressed, a small dose of antidepressant medication may be automatically injected and/or output 3816 may issue an audible message or alarm directing the patient to self-administer a dose of medication. Alternatively, output signal 3816 may be communicatively coupled to a remote monitoring station such as a doctor's pager so that, if a particular reading indicates that the patient has developed a dangerous condition, a doctor may be paged for response and/or an alarm may be set to direct the patient to seek medical attention.

Another benefit of the at-home system 3800 is the volume and completeness of patient data resulting from the continuous recording and measurement of the patient's vital organs and/or other physiological and/or neurological conditions. People are often asked what they were doing just before and after a medical event, such as a seizure. Patients often have difficulty tracking and/or recalling their daily activities with such precision. However, in the example system 3800, a local analyzer 3814 records the patient's statistics and/or activities. The example self-applied system disclosed herein enables the development of a daily log or flow chart of brain activity, which can be used to identify relationships and/or trends among behavior, medication, and physiological manifestations. Furthermore, in some examples, the head-mounted device is equipped with geo-tracking technology (e.g., GPS) to identify the patient's location at a specific time (e.g., kitchen, neighbor's house, living room, etc.). In some examples, the local analyzer 3814 prompts the patient to enter their daily activities periodically or upon the occurrence of a specific medical event (e.g., upon a spike in one or more readings). The example system 3800 of FIG. 38 includes a manual input 3818 to facilitate the patient's entry of this information. In some examples, manual input 3818 is carried by head mounted device 3812. For example, manual input 3818 can be an interactive (e.g., touch) screen, a microphone, and/or a keypad on the surface of head mounted device 3812. In other examples, manual input 3818 can be a remote device communicatively coupled to system 3800, such as, for example, a handheld device, a computer, a mobile phone, a tablet, and/or a television.

Thus, the examples disclosed herein enable the collection, recording, charting and/or development of baseline activity and comparison of patient activity to the baseline on an ongoing basis. Baseline development is patient-specific based on the amount of data collected. Therefore, the baseline is not based on social norms or averages, but is transformable and adaptable to individual patients. The example systems and head-mounted devices disclosed herein also include on-board storage, processors, time tracking and spectral tracking to enable continuous charting/state assessment, medical use and/or feedback improvement applications of patients, thereby increasing patient compliance and/or response. In some examples, the self-application systems disclosed herein also provide prompts in response to potentially significant events. For example, the examples disclosed herein can prompt a patient to see a physician when needed. In some examples, these prompts are based on changes in mental state and/or activity and/or significant deviations from the norms of an individual patient, so that the response or action prompt is customized for a specific individual.

The volume and completeness of data collected by example system 3800 enables the development of real-time reports that provide valuable data for diagnosing and treating medical conditions. For example, a patient with ADHD may have a reading indicating increased brain activity in a specific area of the brain associated with attention deficit. In response, local analyzer 3814 can prompt the user via manual input 3818 to enter what the patient recently did (e.g., drank a can of Coke). In another example, a depressed patient may have a reading indicating they are cheerful and happy. Local analyzer 3814 will prompt the patient to record what they were doing just before the reading. This activity can be incorporated into a treatment plan to help the patient maintain a desired mental state (e.g., happiness). In another example, a person with hypertension can be monitored. If their blood pressure is elevated, the patient can be asked what they ate or drank just before the reading. Thus, with example system 3800, patients can easily enter data, and physicians can interpret the data and more accurately diagnose health conditions and/or activities that influence them.

Although an example manner of implementing the system 3800 has been illustrated in FIG38, one or more of the elements, processes, and/or devices illustrated in FIG38 may be combined, divided, rearranged, omitted, eliminated, and/or implemented in any other manner. Furthermore, the example local analyzer 3814, the example clock 3826, the example database 3828, the example output 3816, the example manual input 3818, the example EEG subsystem 3802, the example EKG subsystem 3804, the example glucose monitoring subsystem 3806, the example EOG subsystem 3808, the example facial monitoring system 3809, the example plug-in/plug-and-play device 3810, and/or more generally the example system 3800 of FIG38 may be implemented by hardware, software, firmware, and/or any combination of hardware, software, and/or firmware. Thus, for example, the example local analyzer 3814, the example clock 3826, the example database 3828, the example output 3816, the example manual input 3818, the example EEG subsystem 3802, the example EKG subsystem 3804, the example glucose monitoring subsystem 3806, the example EOG subsystem 3808, the example facial monitoring system 3809, the example plug-in/plug-and-play device 3810, and/or more generally the example system 3800 of FIG. 38 can be implemented via one or more circuits, programmable processors, application specific integrated circuits (ASICs), programmable logic devices (PLDs) and/or field programmable logic devices (FPLDs), etc. In the event that any apparatus or system claim of this patent is interpreted as covering purely software and/or firmware implementations, at least one of the example local analyzer 3814, the example clock 3826, the example database 3828, the example output 3816, the example manual input 3818, the example EEG subsystem 3802, the example EKG subsystem 3804, the example glucose monitoring subsystem 3806, the example EOG subsystem 3808, the example facial monitoring system 3809, or the example plug-in/plug-and-play device 3810 is hereby expressly defined as comprising hardware and/or tangible computer-readable media such as memory, DVD, CD, etc. storing software and/or firmware. Further, the example system 3800 of FIG38 may include one or more elements, processes, and/or devices in addition to or in place of those illustrated in FIG38, and/or may include more than one of any or all of the illustrated elements, processes, and devices.

FIG39 illustrates an example attention and control system 3900, which can be used to determine, process, and/or assess a user's attention to media and/or to manipulate inputs on an external electronic device without physical movement (e.g., using only the user's thoughts). Example system 3900 includes a head-mounted device 3902, which can be implemented, for example, using the example head-mounted devices and/or systems disclosed herein, such as head-mounted device 100 of FIG1 , head-mounted device 2300 of FIG23 , and/or head-mounted device 3400 of FIG34 . Head-mounted device 3902 processes EEG signals and/or other sensor data to develop an image of the user's mental state, including, for example, an affective state, an engaged state, an attentive state, and/or any other neural state. As disclosed below, example system 3900 of FIG39 can be used to determine whether a user is paying attention to a media program, determine where a user's eyes are focused, determine that a user intends to control a remote device and implement that control (e.g., changing the volume on a television), and/or other applications. In the illustrated example system 3900, a head-mounted device 3902 includes an analyzer component that includes an EEG sensor 3904, a program identifier 3906, a telekinesis evaluator 3908, an eye-tracking sensor 3910, an accelerometer 3911, an attention evaluator 3912, a database 3914, and a transmitter 3916. The analyzer components 3904-3914 are communicatively coupled via a communication link 3918, such as, for example, any of the communications described above. The analyzer components 3904-3914 can, for example, be incorporated into or otherwise supported by a head-mounted device 3902, such as the head-mounted device 100 shown in FIG. 1 , the head-mounted device 2300 shown in FIG. 23 , or the head-mounted device 3400 shown in FIG. 34 . In some examples, the analyzer components 3904-3916 are housed in a compartment on the head-mounted device, such as the second housing 128 of the head-mounted device 100 shown in FIG. 1-3 .

As disclosed above, the example head-mounted devices 100, 2300, and 3400 include multiple individual electrodes to detect electrical activity along the user's scalp. This data can be used to determine attention, memory, concentration, and/or other neural states. The example EEG sensor 3904 of FIG39 is implemented by the electrodes of the head-mounted device disclosed above.

An example eye-tracking sensor 3910 is used to track eye movements and/or the direction in which a user's eyes are directed. For example, eye-tracking sensor 3910 can be a camera or other sensor incorporated into an attachment extending from head-mounted device 3902 and directed toward one or both eyes of the user. In other examples, eye-tracking sensor 3910 can be a camera or other sensor on or near a computer, television, mobile phone screen, or other location to collect data related to the user's eye movements. Eye-tracking sensor 3910 can continuously record what the subject is looking at. In some examples, the eye-tracking sensor is positioned around the middle of the subject's eyebrows. Additionally, in some examples, the eye-tracking sensor includes an infrared (IR) camera for one or both eyes (e.g., a monocular or binocular mask) to track the position of the pupil and/or corneal reflection, thereby assisting in determining the subject's gaze point. In some examples, eye-tracking sensor 3910 is incorporated into and/or used in conjunction with accelerometer/gesture measurement system 3911. Many mobile eye tracking systems that are mounted to the subject's head are susceptible to error measurements because the subject moves their head relative to the position they were in during system calibration. The example accelerometer 3911 continuously tracks the relative eye position to the calibration, which enhances the accuracy of the gaze point measurement from the eye tracking sensor 3910.

Eye tracking data can be synchronized with EEG data and/or otherwise used to corroborate EEG data, or can be used in other ways in conjunction with EEG to determine a user's neurological state. Eye movements provide a target for the user's attention allocation. For example, if a user looks in the direction of a television and their EEG data indicates that they are engaged or paying attention, the eye tracking data and EEG data together confirm that attention is likely directed to the television.

The example system of Figure 39 also includes a database 3914 for local storage of raw data, processed data, result data, historical logs, program data from media sources, and/or any other type of data. The illustrated example transmitter 3916 transmits data at any processing stage and/or analysis results from the head mounted device 3902 to a remote data facility 3920 and/or an electrical device 3922, as disclosed in more detail below.

In some example embodiments, system 3900 is used to collect audience measurement data. Example system 3900 determines whether a user's neurological state indicates that the user is focused (e.g., engaged) while viewing a particular media. Program identifier 3906 identifies the media to which the user is exposed. Program identification can be performed using any technique, for example, by using a microphone on a head-mounted device to collect audio signals to collect audio codes and/or logos to identify programs, as disclosed in U.S. Pat. No. 5,481,294 to Thomas. Program identifier 3906 collects data about media, such as, for example, television programs, advertisements, movies, news clips, radio programs, web pages, or any other media, and identifies the media (e.g., content or advertisements) based on the collected data, and/or forwards the collected data to another device to perform identification.

In collecting audience measurement data, example system 3900 collects EEG data from EEG sensor 3904 of head-mounted device 3902. The system also collects eye-tracking data from eye-tracking system 3910 to determine where the user is looking during a media broadcast. Attention evaluator 3912 uses data from EEG sensor 3904 and eye-tracking sensor 3910 to determine whether the user is paying attention to the media. For example, if EEG sensor 3904 detects brain waves (i.e., electrical activity) indicating increased thinking, and eye-tracking sensor 3910 determines that the user is watching television, attention evaluator 3912 will output a signal indicating that the user is focused and immersed in the particular media program being broadcast. However, if program identifier 3906 determines that a particular program is being presented, and EEG sensor 3904 indicates decreased brain activity, or if eye-tracking sensor 3910 determines that the user is not watching television, attention evaluator 3912 will output a signal indicating that the user is not focused or immersed in the particular media program being broadcast.

Data reflecting whether the user is paying attention to the program, not paying attention to the program, or semi-engaged in the program, as well as the program's identity, can be stored in a database 3914 and transmitted by a transmitter 3916 to an output, including, for example, a remote data facility 3920. Raw data, processed data, historical logs, or audience measurement indicators can also be sent to the remote data facility 3920 for collection. The remote data facility 3920 can be, for example, a marketing company, a broadcaster, an entertainment studio, a television network, and/or any other organization that might benefit from or otherwise desire to know when a user is and/or is not paying attention to broadcast programs, and what those programs are. In some examples, the head-mounted device 3902 is communicatively coupled to the remote data facility 3920 via a communication channel 3924, such as a public telephone line, a landline, an internet connection, radio waves, and/or any other communication technology capable of transmitting signals. This allows broadcasters and/or marketers to analyze which programs people are watching, when they are watching those programs, and/or when they are paying attention during a broadcast.

In another example embodiment, the example system 3900 and head-mounted device 3902 operate as a direct neural interface, or brain-machine interface (BMI), for generating input to an electrical device 3922, such as, for example, a television, radio, computer mouse, computer keyboard, remote control, microwave, application interface, and/or other device. The input signal to the electrical device 3922 is based on data from the EEG sensor 3904 and/or eye-tracking sensor 3910 of the head-mounted device 3902. For example, the eye-tracking sensor 3910 determines that the user is gazing at a specific area of their computer, and the EEG sensor 3904 detects electrical activity indicative of concentration. The system 3900 for controlling the electrical device 3922 uses specific EEG markers to trigger control, including, for example, markers in the somatosensory system that are centered on the sensorimotor cortex contralateral to the movement and include changes in the μ (e.g., 10-14 Hz) and β (e.g., 15-30 Hz) rhythms. Based on the EEG and eye-tracking data, a telemotion evaluator 3908 of the head-mounted device 3902 determines that the user wants to move their cursor (i.e., mouse) to a different area of the computer screen. The telemotion evaluator 3908 sends a signal to an electrical device 3922 via a transmitter 3916 to move the cursor on the screen. In another example, the telemotion evaluator 3908 analyzes data from the EEG sensor 3904 and determines that the user wants to change the volume level on the television. The telemotion evaluator 3908 sends a signal to an electrical device 3922 (i.e., a television or cable receiver) via a transmitter 3916 to change the volume level. In the example shown, the head-mounted device 3902 is communicatively coupled to the electrical device 3922 via a communication link 3926, which can be a hardwired or wireless communication technology, such as any of the communication links discussed herein. In some examples, the telekinesis evaluator develops signals for performing a number of other functions, such as, for example, muting a television, changing channels, turning a television, computer, or other device on or off, opening a specific program on a computer, setting a microwave, making a music selection, operating a remote control, operating a stereo in a car, operating a light switch, answering a phone call, operating a DVR (digital video recorder) and/or video on demand, and/or any other function that would typically involve a user pressing a button on a device or a remote control for the device. EEG signals that include changes in somatosensory μ and β rhythms are also used in other brain-computer interface applications, including, for example, driving a wheelchair, controlling a small robot, controlling an exoskeleton device on a paralyzed limb, and/or other functions.

Although an example manner of implementing system 3900 has been illustrated in FIG39, one or more of the elements, processes, and/or devices illustrated in FIG39 may be combined, divided, rearranged, omitted, eliminated, and/or implemented in any other manner. Furthermore, the example program identifier 3906, the example remote action evaluator 3908, the example attention evaluator 3912, the example database 3914, the example transmitter 3916, the example remote data facility 3920, the example electrical device 3922, and/or more generally the example system 3900 of FIG39 may be implemented by hardware, software, firmware, and/or any combination of hardware, software, and/or firmware. Thus, for example, the example program identifier 3906, the example remote motion evaluator 3908, the example attention evaluator 3912, the example database 3914, the example transmitter 3916, the example remote data facility 3920, the example electrical device 3922, and/or more generally the example system 3900 of FIG. 39 can be implemented by one or more circuits, programmable processors, application specific integrated circuits (ASICs), programmable logic devices (PLDs), and/or field programmable logic devices (FPLDs), etc. Where any apparatus or system claim of this patent is to be construed to cover purely software and/or firmware implementations, at least one of the example program identifier 3906, the example remote motion evaluator 3908, the example attention evaluator 3912, the example database 3914, the example transmitter 3916, the example remote data facility 3920, or the example electrical device 3922 is hereby expressly defined as comprising hardware and/or tangible computer-readable media, such as memory, DVDs, CDs, etc., storing software and/or firmware. Further, the example system 3900 of FIG. 39 may include one or more elements, processes and/or devices in addition to or in place of those illustrated in FIG. 39 , and/or may include more than one of any or all of the illustrated elements, processes and devices.

40-44 are flow diagrams that at least partially represent example machine-readable instructions that may be executed to implement the example head mounted devices 100, 2300, 3400, 3812, 3902 and/or the example systems 3600, 3700, 3800, 3900. In the examples of FIGs. 40-44, the machine-readable instructions comprise a program for execution by a processor, such as the processor 4512 shown in the example processing platform 4500 discussed below in conjunction with FIG. 45. The program may be embodied as software stored on a tangible computer-readable medium, such as a CD-ROM, floppy disk, hard drive, digital versatile disk (DVD), or memory associated with the processor 4512, although the entire program and/or portions thereof may alternatively be executed by a device other than the processor 4512 and/or embodied as firmware or dedicated hardware. 40-44 , many other methods of implementing the example head mounted devices 100, 2300, 3400, 3812, 3902 and/or the example systems 3600, 3700, 3800, 3900 may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined.

As mentioned above, the example processes of Figures 40-44 can be implemented at least in part using coded instructions (e.g., computer-readable instructions) stored on a tangible computer-readable medium, such as a hard drive, flash memory, read-only memory (ROM), a compact disk (CD), a digital versatile disk (DVD), a cache, random access memory (RAM), and/or any other storage medium in which information is stored for any duration (e.g., for an extended period of time, permanently, for a transient moment, for temporary buffering, and/or for information caching). As used herein, the term tangible computer-readable medium is expressly defined to include any type of computer-readable storage medium and excludes propagating signals. Additionally or alternatively, the example processes of Figures 40-44 can be implemented at least in part using coded instructions (e.g., computer-readable instructions) stored on a non-transitory computer-readable medium, such as a hard drive, flash memory, read-only memory, a compact disk, a digital versatile disk, a cache, random access memory, and/or any other storage medium in which information is stored for any duration (e.g., for an extended period of time, permanently, for a transient moment, for temporary buffering, and/or for information caching). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable medium and to exclude propagating signals.

FIG40 is a flow chart illustrating an example process for analyzing EEG data collected from an example head-mounted device 100, 2300, 3400, 3812, or 3902 (block 4000) and implemented by the example system 3600 of FIG36. The example head-mounted device 100, 2300, 3400, 3812, or 3902 has a plurality of electrodes that contact a subject's scalp to receive electrical signals from the subject's brain. The example process (4000) for analyzing EEG data includes reading EEG signals from the electrodes (block 4002). In the illustrated example, the signals are converted from analog to digital (block 4004). In some examples, the analog-to-digital conversion occurs in a processing unit, such as, for example, the processing unit 3604 of the example system 3600. In other examples, the analog-to-digital conversion occurs near the electrodes within the head-mounted device to convert the signals as close to the source as possible.

In the illustrated example, the signal is conditioned (block 4006) to improve the usefulness of the signal and the accessibility of the data contained therein. For example, as disclosed above, conditioning can include amplifying the signal and/or filtering the signal (e.g., using a bandpass filter). The signal is analyzed (block 4008) to determine, for example, the subject's mental state, health, engagement with the media as an audience member, input expectations for an electrical device, and/or other content in accordance with the teachings of the present disclosure.

In the illustrated example, a signal is sent to an output (block 4010), such as output 3618 of the example system 3600. Example modes of output are detailed above and include, for example, sounding an alarm, displaying a message and/or other alert on a screen, sending a report to a local and/or remote computer, and/or any other suitable output. Additionally, output can include wired or wireless communication as detailed herein. After output (block 4010), the example process (4000) ends (block 4012).

FIG41 is a flow diagram illustrating an example process for improving the quality of an EEG signal (block 4100) collected, for example, from one or more example head-mounted devices 100, 2300, 3400, 3812, 3902 and implemented by the example system 3700 of FIG37. The example head-mounted devices 100, 2300, 3400, 3812, 3902 include a plurality of electrodes (i.e., input channels) that contact a subject's head to receive electrical signals from the subject's brain. In some examples, the example process for improving signal quality (4100) is implemented by a processor located at the head-mounted device, such as, for example, located in the second housing 128 of the head-mounted device 100 shown in FIG1-3. In other examples, the example process for improving signal quality (4100) occurs at a remote site, such as, for example, a handheld device, a local computer, a remote server, and/or another suitable device.

The example process (4100) includes receiving signals from one or more input channels (e.g., electrodes) (block 4102). In some examples, the analyzer 3712 of the system 3700 receives the signals from the input channels for analysis. One or more properties of the one or more signals are evaluated (block 4104). For example, the signals are evaluated to determine signal strength, amplitude, signal-to-noise ratio, duration, and/or other characteristics according to the teachings of the present disclosure.

In the illustrated example process (4100), one or more signals are conditioned (block 4106) to improve signal quality. In some examples, conditioning the signals enhances signal quality to an acceptable level so that the signals are usable. In other examples, signal conditioning may not provide sufficient improvement to the signals. The example process (4100) further includes selecting one or more signals for use, ignoring one or more signals, or merging two or more signals (block 4108). As disclosed above, two or more signals can be merged by short-circuiting one of the signals, coupling electrodes providing the signals in parallel, and/or averaging the two or more signals, which reduces impedance and improves signal quality, as described in detail above. The example process (4100) improves signal quality by selecting those signals for use and by ignoring signals of poor quality. After selecting valuable and/or improved signals (block 4108), the example process (4100) for improving signal quality ends (block 4110), and the signals and the content contained therein can be used in other processes, such as, for example, the example analysis process (4000) of FIG. 40 .

FIG42 is a flow chart illustrating an example process for performing at-home patient monitoring and treatment (block 4200) using an example head-mounted device 100, 2300, 3400, 3812, 3902 and implemented by the example system 3800 of FIG38. As disclosed above, the example head-mounted device 100, 2300, 3400, 3812, 3902 has a plurality of electrodes that contact the subject's scalp to receive electrical signals from the subject's brain. In some examples, the head-mounted device 100, 2300, 3400, 3812, 3902 is worn by a subject for at-home monitoring, treatment, and/or diagnosis of a medical condition, to detect life-threatening conditions, to determine a patient's compliance with a prescribed medical regimen, and/or other suitable applications according to the teachings of the present disclosure.

The example process (4200) includes collecting signals from electrodes or other suitable sensors (box 4202). As discussed above, the at-home patient monitoring system can combine not only EEG readings from the example head-mounted device, but also other biometric, neural and/or physiological systems to monitor, treat and/or diagnose medical conditions of the at-home patient. One or more signals are analyzed (box 4204) to determine the mental/physical state of the at-home patient. The signals can be analyzed, for example, using an analyzer or processor, such as the processor 134 disclosed above in the second housing 128 of the head-mounted device 100 shown in Figures 1-3. One or more signals can be conditioned and filtered according to the teachings of the present disclosure, such as, for example, as disclosed in the example process (4000) of Figure 40 and/or the example process (4100) of Figure 41.

The example process (4200) determines whether a signal, an analysis of the signal, or a notification regarding the signal (e.g., such as an alarm and/or other suitable communication) should be sent to a remote facility (block 4206). The remote facility can be, for example, a doctor's office, a hospital, a clinic, a laboratory, an archive, a research facility, and/or any other diagnostic facility. For example, if the signal indicates that a heart attack, a stroke, an epileptic seizure, and/or a fall has occurred or is about to occur, the example process (4200) determines whether the signal, analysis, or notification should be sent to the remote facility (block 4206), and the example process (4200) sends the signal and/or notification or alarm to the remote facility (block 4208). After sending the communication to the remote facility (block 4208), the example process (4200) can end (block 4218) or continue monitoring the subject by collecting signals from the sensor (block 4202).

If the example process (4200) determines that the signal, analysis, or notification is not to be sent to the remote facility (block 4206), the example process (4200) determines whether to generate an output signal (block 4210) (such as, for example, to alert the patient to a condition or to remind him or her of an activity as disclosed in this patent). If an output signal (block 4210) is not to be generated (such as, for example, a signal indicating that the patient's condition is normal and/or the data is otherwise benign), the example process can end (block 4218) or continue monitoring the subject by collecting signals from the sensors (block 4202).

If the example process (4200) determines that an output signal should be generated (block 4210), various types of outputs may be generated, including any suitable output disclosed herein, such as, for example, prompting the user for input (block 4212). As discussed above, patients often experience difficulty tracking and/or recalling their daily activities. If the analysis indicates a particular spike in readings occurred, the output signal (block 4210) may prompt the user for input (block 4212) what he/she was doing just before the spike.

In another example, the output signal (block 4210) enables the automatic delivery of medication (block 4214). For example, if the patient is diabetic, they may require continuous glucose and blood pressure monitoring. The process can automatically deliver a dose of medication to the patient when their readings require it (e.g., the signal indicates a medication dose is needed).

In another example, the output signal (block 4210) generates a signal (block 4216), such as light, sound, display, and/or any other output, for example, to alert the patient to the need to seek medical attention, take a dose of medication, start an activity, stop an activity, eat, and/or any other suitable warning and/or command. After generating one or more outputs (blocks 4212, 4214, 4216), the example process (4200) can end (block 4218) or continue monitoring the subject by collecting signals from the sensor (block 4202).

FIG43 is a flow chart illustrating an example process for assessing a user's attention to a program and/or manipulating one or more electrical devices (block 4300) using an example head mounted device 100, 2300, 3400, 3812, 3900 and implemented by the example system 3900 of FIG39. The example head mounted device 100, 2300, 3400, 3812, 3900 includes a plurality of electrodes to receive electrical signals from the brain for processing according to the example process 4300. The example process 4300 illustrates the utility of EEG data and other physiological data (e.g., eye tracking data) for a variety of purposes.

The example process (4300) includes collecting signals from EEG sensors (e.g., electrodes and/or input channels) (block 4302). Data from these signals is used to determine attention, memory, concentration, and/or other neural states. The example process (4300) also includes collecting signals from eye-tracking sensors (block 4304). As discussed above, eye-tracking data can be used to corroborate EEG data, and both sets of data (e.g., EEG and eye-tracking) can be used to determine the user's neural state (block 4306).

In an example embodiment, the user's neural state (block 4306) is useful for audience measurement. For example, if the user looks in the direction of a television and their EEG data indicates that they are engaged or paying attention, the eye tracking data and the EEG data together confirm that the user is paying attention to the program. The example process (4300) also identifies what media or program the user is exposed to (block 4308). For example, the process (4300) can use a microphone and/or use any other device according to the teachings of the present disclosure to collect audio codes and/or logos. Based on the collected data, the example process (4300) identifies the program or media to which the user is exposed (block 4308). In the illustrated example, data reflecting whether the user is paying attention and what program the user is or is not paying attention to is sent to a remote facility (block 4310). As discussed above, the remote facility can be a marketing company, a broadcaster, or any other organization that may benefit from or otherwise desire to know when a user is paying attention and/or not paying attention to a broadcast program. After sending the results (block 4310), the example process (4300) may end (block 4316).

In another example embodiment, the user's neural state (block 4306) is useful in assessing whether the user desires to manipulate a device (block 4312), including, for example, an electrical device as disclosed above. For example, EEG data and eye tracking data may indicate that the user is looking at a particular area of his/her computer and/or that the user has an increased level of concentration. The example process (4300) determines that the user desires to control a device (e.g., a computer) by, for example, opening a new application and/or moving a cursor. If the example process (4300) determines that the user desires to control a device (block 4312), the example process (4300) sends a signal to the device (block 4314) to implement the desired control of the device, as disclosed above. After sending the control signal (block 4314), the example process (4300) may end (block 4316).

FIG44 is a flow chart illustrating an example process for collecting and analyzing EEG data (block 4400), which can be implemented, for example, using any of the head-mounted devices and/or systems disclosed herein. The example process (4400) begins by placing a head-mounted device on a subject's head (block 4402). As disclosed above, the example head-mounted device includes multiple adjustable straps that extend over the user's head. The head-mounted device can include three, four, five, or ten or more individual straps. In some examples, the head-mounted device can include fewer straps, such as one or two. The straps are removably and rotatably coupled to a first housing and a second housing at each end. Each strap includes multiple electrodes for reading electrical activity along the user's scalp. The head-mounted device can be oriented so that the first housing is near the user's right ear and the second housing is near the user's left ear. The user can rotate each strap toward the inion (the protrusion of the occipital bone) or the nasion (the intersection of the frontal bone and the two nasal bones) to position the electrodes in a specific location for measuring electrical activity (block 4404). Each strap also includes an elastic strip. The user can adjust the elastic strips on the band to tighten the band and press the electrodes down on the band, toward and against the user's head (block 4406). The user can tighten the back strap to secure the headset to the user's head (block 4408).

The example process (4400) also includes reading EEG data from one or more electrodes, such as disclosed above (block 4410). The raw signals from the electrodes can then be conditioned using hardware, firmware, and/or software components (such as an A/D converter, an amplifier, and/or one or more filters, as disclosed above) (block 4412). In some examples, one or more conditioning components can be incorporated into a housing on the headset, into each adjustable band, at each individual electrode, and/or at a remote processor. In some example implementations of the example process (4400), the user determines whether to rotate the headset 90° (or any other suitable angle) for additional or alternative EEG data (block 4414). In the case of a rotated headset, the band spans from the forehead to the back of the head. This orientation may be desirable, for example, to obtain a midline reading. If the user wishes to obtain additional data in a vertical position (block 4414), they rotate the headset 90° (block 4416) and reposition and adjust the band as described above (blocks 4402-4408). With the headset positioned for the desired reading (block 4414), the conditioned signal is analyzed (block 4418).

The example process (4400) also includes determining whether one or more electrodes need to be or should be adjusted (box 4420). For example, the electrodes should be adjusted to obtain a clearer signal. If one or more electrodes are to be adjusted, the example process (4400) includes determining whether the adjustment is a physical adjustment or a non-physical adjustment (4422). If the adjustment is a physical adjustment (4422), control of the example process (4400) returns to box 4404, and the appropriate (one or more) straps are rotated into place and/or the (one or more) elongated straps or straps are adjusted (boxes 4406-4408). If the (one or more) electrodes are to be non-physically adjusted (4422), the example process (4400) includes virtually moving and/or short-circuiting one or more electrodes (box 4424), as detailed above. If the (one or more) electrodes are adjusted, the example process (4400) returns to continue reading the EEG signal (box 4410), and the example process (4400) continues.

If the electrode(s) do not require further adjustment (block 4424), the signal is analyzed to generate an output assessment or mental image (block 4426). As disclosed above, the output assessment or mental image can determine, for example, the individual's neurological state. For example, as provided in the examples disclosed above, EEG data includes multiple frequency bands that can be analyzed to determine, for example, whether the individual is highly focused, sleeping, depressed, happy, calm, and/or any other emotional and/or neurological state as disclosed above. The output assessment/mental image provides insight into the individual's thinking, emotions, and/or health.

The example method 4400 also includes determining whether the output is to be used with one or more additional applications (block 4428). If the output is to be used with one or more additional applications (such as, for example, medical applications, audience measurement, remote device control, and/or any other suitable application as disclosed herein), such applications are executed (block 4430). The example process (4400) also determines whether monitoring of EEG data should continue (block 4432). If further monitoring is to be performed, control of the method returns to block 4410, and the EEG signal data is read. If no further monitoring is to be performed, the example method 4400 ends (block 4434).

45 is a block diagram of an example processing platform 4500 capable of executing one or more instructions of FIGs. 40-44 to implement one or more portions of the apparatus and/or systems of FIGs. 1, 23, 34, and 36-39. Processing platform 4500 can be, for example, a processor in a head-mounted device, a server, a personal computer, and/or any other type of computing device.

The system 4500 of the present example includes a processor 4512. For example, the processor 4512 can be implemented by one or more microprocessors or controllers from any desired family or manufacturer.

The processor 4512 includes a local memory 4513 (e.g., a cache) and communicates with a main memory including a volatile memory 4514 and a non-volatile memory 4516 via a bus 4518. The volatile memory 4514 may be implemented by synchronous dynamic random access memory (SDRAM), dynamic random access memory (DRAM), RAMBUS dynamic random access memory (RDRAM), and/or any other type of random access memory device. The non-volatile memory 4516 may be implemented by flash memory and/or any other desired type of memory device. Access to the main memories 4514 and 4516 is controlled by a memory controller.

The processing platform 4500 also includes an interface circuit 4520. The interface circuit 4520 may be implemented by any type of interface standard, such as an Ethernet interface, a universal serial bus (USB), and/or a PCI Express interface.

One or more input devices 4522 are connected to the interface circuit 4520. The input device(s) 4522 allow a user to input data and commands into the processor 4512. The input device(s) may be implemented by, for example, electrodes, physiological sensors, a keyboard, a mouse, a touch screen, a trackpad, a trackball, an isopoint, and/or a voice recognition system.

One or more output devices 4524 are also connected to the interface circuit 4520. The output device 4524 may be implemented, for example, by a display device (eg, a liquid crystal display and/or a speaker). The interface circuit 4520 therefore typically includes a graphics driver.

Interface circuitry 4520 also includes a communication device (e.g., transmitter 3616, 3916) such as a modem or network interface card to facilitate data exchange with an external computer via a network 4526 (e.g., an Ethernet connection, a digital subscriber line (DSL), a telephone line, a coaxial cable, a cellular telephone system, etc.).

Processing platform 4500 also includes one or more mass storage devices 4528 for storing software and data. Examples of such mass storage devices 4528 include floppy disk drives, hard disk drives, compact disk drives, and digital versatile disk (DVD) drives. Mass storage devices 4528 can implement local storage devices 3612, 3822, and 3914.

The coded instructions 4532 of Figures 40-44 may be stored in the mass storage device 4528, in the volatile memory 4514, in the non-volatile memory 4516, and/or on a removable storage medium such as a CD or DVD.

Although certain example apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.

Claims (35)

1. A device for collecting electroencephalogram (EEG) data, comprising: The central body portion includes a first protrusion, a second protrusion, and a recess between the first protrusion and the second protrusion; Multiple extensions extending from the central main body, each extension having a corresponding end bearing an electrode; and An adjustment band is provided in the recess along the longitudinal axis of the central main body to adjust the corresponding position of the extension. 2. The device according to claim 1, wherein the adjusting belt is elastic. 3. The device according to claim 1, wherein the adjusting belt is slidably disposed along the longitudinal axis. 4. The device according to any one of claims 1 to 3, further comprising a flexible printed circuit board encapsulated in the central body portion and the extension portion. 5. The device according to any one of claims 1 to 3, wherein a plurality of extensions in the extensions are bent in a direction away from the central body portion. 6. The device according to claim 5, wherein the extensions are bent in the same direction. 7. The apparatus according to any one of claims 1 to 3, wherein the electrode comprises at least a portion of a ring. 8. The apparatus according to any one of claims 1 to 3, further comprising an electrode array disposed on one side of the central body portion. 9. The device according to any one of claims 1 to 3, wherein tightening of the adjusting band causes the electrodes to apply force to the head of the person wearing the device. 10. The device according to any one of claims 1 to 3, wherein the central body portion and the extension portion are flexible but not elastic, while the adjustment belt is flexible and elastic. 11. The apparatus according to any one of claims 1 to 3, further comprising a silver nylon coating on the electrodes. 12. The device according to any one of claims 1 to 3, wherein the electrodes are removable. 13. The apparatus according to any one of claims 1 to 3, wherein the first extension of the plurality of extensions is located opposite the second extension of the plurality of extensions across the central body portion. 14. The apparatus according to any one of claims 1 to 3, further comprising a cover partially surrounding the electrode such that a first portion of the cover is disposed on a first side of the electrode, a second portion of the cover is disposed on a second side of the electrode, and an end of the electrode that is in contact with the target tissue extends from the cover. 15. The device of claim 14, wherein the electrode has a cross-section of less than 0.5 mm, the first outer end of the first portion of the cover and the second outer end of the second portion of the cover are separated by a distance of less than 1 mm, and the end of the contact tissue of the electrode extends from the cover by less than 0.2 mm. 16. The apparatus of claim 14, wherein the electrodes carried by the extension are a first set of electrodes, further comprising a second set of electrodes carried by the central body, the first set of electrodes comprising electrodes of a first type, and the second set of electrodes comprising electrodes of a second type different from the first type. 17. The apparatus of claim 16, wherein the first type of electrode comprises individually mounted electrodes, and the second type of electrode comprises an electrode array. 18. The apparatus of claim 17, wherein two or more electrodes in the array are electrically short-circuited to form an electrode having an increased surface area. 19. The apparatus according to any one of claims 16 or 17, wherein the first set of electrodes is disposed along a first outer side of the central body portion and along a second outer side of the central body portion, and the second set of electrodes is disposed along the central axis of the central body portion. 20. The device of claim 1, wherein the central body portion is a first elongated band coupled to a first housing positioned near a first ear of a subject and a second housing positioned near a second ear of a subject, the first elongated band including a first set of electrodes having at least eight electrodes, further comprising: A second elongated strip coupled to a first housing and a second housing, the second elongated strip including a second set of electrodes having at least eight electrodes; A third elongated strip, coupled to the first and second housings, includes a third set of electrodes having at least eight electrodes; and A fourth elongated strip coupled to the first and second housings, the fourth elongated strip comprising a fourth set of electrodes having at least eight electrodes. 21. The device of claim 20, wherein one or more of the first, second, third, and fourth elongated strips are rotatably coupled to one or more of the first housing and the second housing. 22. The device according to any one of claims 20 or 21, wherein one or more of the first, second, third and fourth elongated strips are detachably coupled to one or more of the first housing and the second housing. 23. The device according to any one of claims 20 or 21, wherein the first elongated band is positioned above the root of the nose of the subject at 10% of the distance between the root of the nose and the occipital protuberance as measured at the center of the subject's head, the second elongated band is positioned above the root of the nose at 30% of the distance, the third elongated band is positioned midway between the root of the nose and the occipital protuberance, and the fourth elongated band is positioned above the occipital protuberance at 30% of the distance. 24. The device according to any one of claims 20 or 21, wherein one or more of the first, second, third and fourth elongated bands include an adjustable elastic band to change the distance between the elongated band and the object head. 25. The apparatus of any one of claims 20 or 21, further comprising an additional elongated strip coupled to the first housing and the second housing, the additional elongated strip comprising an additional electrode assembly. 26. The apparatus according to any one of claims 20 or 21, wherein one or more electrodes in the first group of electrodes compress the stratum corneum of the object with a force of 1 Newton per square millimeter to 2 Newtons per square millimeter. 27. The apparatus according to any one of claims 20 or 21, further comprising: An analog-to-digital converter used to convert signals collected by electrodes into digital data; Amplifiers used to amplify signals; A signal conditioner used to remove noise from a signal; A data processor used to analyze data according to an analysis protocol to determine the mental state of an object; and A transmitter used to send at least one of digital data or mental states. 28. The apparatus of claim 1, further comprising a first strip, the first strip including a central body portion, wherein the electrodes are a first set of electrodes, further comprising: The second band includes a second set of electrodes, wherein the first and second bands are oriented relative to the head of the subject in a first direction to obtain first neural response data from the subject, and the first and second bands are oriented relative to the head of the subject in a second direction to obtain second neural response data from the subject, the second direction being substantially perpendicular to the first direction. 29. The apparatus of claim 28, wherein the apparatus in the second direction collects midline readings from the brain of the subject. 30. The apparatus of claim 1, further comprising a first housing, the first housing including a plurality of magnetic locks, wherein the adjustment band is a first adjustment band, wherein the central body portion is a first elongated band having a first end adjustablely coupled to the first housing, the first adjustment band including a first magnetic fastener for magnetically connecting with a first magnetic lock to secure the first elongated band in a first position, and for magnetically connecting with a second magnetic lock to secure the first elongated band in a second position. 31. The device of claim 30, wherein the device is worn on the head of the subject, wherein the first position is closer to the top of the head than the second position, and the adjustment of the first magnetic fastener from the first position to the second position tightens the first elongated band and brings the electrodes closer to the head. 32. The device according to any one of claims 30 or 31, wherein the first elongated strip is detachably coupled to the first housing. 33. The apparatus according to any one of claims 30 or 31, further comprising: a second elongated strip having a second end adjustablely coupled to a first housing, the second elongated strip including a second plurality of electrodes and a second adjustment strip, the second adjustment strip including a second magnetic fastener for magnetically linking with a first magnetic lock in a magnetic lock to secure the second elongated strip in a third position, and for magnetically linking with a second magnetic lock in a magnetic lock to secure the second elongated strip in a fourth position. 34. The device according to claim 33, wherein the first elongated strip and the second elongated strip are independently adjustable. 35. The device of claim 33, wherein the first elongated strip and the second elongated strip are independently detachable.