WO2025207347A1 - Electroencephalogram sensor with multiple active electrodes - Google Patents

Abstract

A wireless electroencephalography (EEG) sensor and associated systems and methods for determining a local EEG signal magnitude and direction are provided. The wireless EEG sensor may include a first active electrode spaced a distance away from a reference electrode along a first axis and a second active electrode spaced a distance away from a reference electrode along a second axis. The first active electrode may collect a first EEG signal along the first axis, and the second active electrode may collect a second EEG signal along the second axis. An electronic circuitry may determine the magnitude and/or a direction of the local EEG signal based on the first EEG signal and the second EEG signal to create a processed EEG signal. The electronic circuitry may provide the processed EEG signal to an EEG monitoring system.

Description

ELECTROENCEPHALOGRAM SENSOR WITH MULTIPLE ACTIVE

ELECTRODES

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/570760, filed on March 27, 2024, which is incorporated by reference in its entirety. Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

[0002] An electroencephalogram (“EEG”) is a diagnostic tool that measures and records the electrical activity of a person's brain in order to evaluate cerebral functions. Multiple electrodes are attached to a person's head and connected to a machine by wires. The machine amplifies the signals and records the electrical activity of a person's brain. The electrical activity is produced by the summation of neural activity across a plurality of neurons. These neurons generate small electric voltage fields. The aggregate of these electric voltage fields create an electrical reading which electrodes on the person's head are able to detect and record. The monitoring of the amplitude and temporal dynamics of the electrical signals provides information about the underlying neural activity and medical conditions of the person.

[0003] There are thousands of hospitals across the United States. Many of these hospitals are community or rural hospitals. These community or rural hospitals conventionally are part of a hospital system or network. An example of one such network includes several community hospitals with one major tertiary hospital. A community or rural hospital outside of any large hospital network would typically contract with a large tertiary hospital for emergent and intensive-care solutions outside of the areas of expertise of the community or rural hospital.

[0004] EEG monitoring is conventionally only available in large tertiary hospitals that support a neurology department with an EEG service. Many hospitals do not offer EEG monitoring. These hospitals make arrangements with larger tertiary hospitals or their partners when such monitoring is required or desirable for patients. This conventionally takes the form of a referral of the patient to the tertiary hospital for expert of specialist services. Often this includes travel or transport of the patient to the tertiary hospital for services. This creates many problems particularly for patients in rural areas. As a result, it is desirable to provide improvements in EEG monitoring systems and methods.

SUMMARY

[0005] An EEG can be performed to diagnose epilepsy, verify problems with loss of consciousness or dementia, verify brain activity for a person in a coma, study sleep disorders, monitor brain activity during surgery, and monitor additional physical problems. An appropriate treatment plan can be developed based on the EEG.

[0006] Disclosed herein are systems, methods, and computer-readable media for monitoring brain activity using one or more wireless EEG sensors configured to be removably placed in one or more locations on a scalp of a patient.

[0007] In some implementations, the techniques described herein relate to a wireless electroencephalogram (EEG) sensor configured to detect brain activity. The wireless EEG sensor can include: a housing and a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals. The plurality of electrodes can include: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode and configured to monitor a first EEG signal along the first axis; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode and configured to monitor a second EEG signal along the second axis. The second axis may be perpendicular to the first axis. The wireless EEG sensor may include an electronic circuitry supported by the housing. The electronic circuitry may be configured to process the EEG signals detected by the plurality of electrodes and determine a magnitude of a combined EEG signal based on the first EEG signal and the second EEG signal.

[0008] The plurality of electrodes may be configured to monitor the EEG signals along the first axis and the second axis to enable EEG activity to be detected regardless of an orientation of the wireless EEG sensor.

[0009] The electronic circuitry may be configured to determine a direction of the combined EEG signal based on the first EEG signal, the second EEG signal, and an arrangement of the reference electrode, the first working electrode, and the second working electrode. The direction may include an angle between the combined EEG signal and the first axis.

[0010] A first distance between the first working electrode and the reference electrode may be equal to or less than 30 millimeters, and a second distance between the second working electrode and the reference electrode may be equal to or less than 30 millimeters. The first distance and the second distance may be equal to or less than 20 millimeters. The first distance and the second distance may be equal to about 18 millimeters. The wireless EEG sensor can be a dual -bipolar sensor.

[0011] According to some implementations, the techniques described herein relate to a system for detecting brain activity. The system can include at least one wireless electroencephalogram (EEG) sensor. The wireless EEG sensor can include: a housing and a plurality of electrodes may be disposed on an exterior surface of the housing and configured to detect EEG signal. The plurality of electrodes can include: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode and configured to monitor a first EEG signal along the first axis; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode and configured to monitor a second EEG signal along the second axis. The second axis may be perpendicular to the first axis. The system may include a non- transitory computer-readable medium storing executable instructions that, when executed by at least one processor, cause the at least one processor to: receive the first EEG signal and the second EEG signal from the at least one wireless EEG sensor; and determine a magnitude of a combined EEG signal based on the first EEG signal and the second EEG signal.

[0012] The at least one wireless EEG sensor may be configured to monitor EEG activity regardless of an orientation of the at least one wireless EEG sensor. The magnitude of the combined EEG signal may be represented as a single scalar quantity.

[0013] The instructions may further be configured to cause the at least one processor to determine a direction of the combined EEG signal based on the first EEG signal and the second EEG signal.

[0014] A first distance between the first working electrode and the reference electrode may be equal to or less than 30 millimeters, and a second distance between the second working electrode and the reference electrode may be equal to or less than 30 millimeters. The first distance and the second distance may be equal to or less than 20 millimeters. The first distance and the second distance may be equal to about 18 millimeters.

[0015] The instructions may be configured to cause the at least one processor to provide instructions for placing the at least one wireless EEG sensor on a scalp of a patient based on the configuration of the reference electrode, the first working electrode, and the second working electrode.

[0016] The instructions may be configured to cause the at least one processor to: determine a direction of the combined EEG signal based on the EEG signals, a location and an orientation of the at least one wireless EEG sensor on the scalp of the patient, and the configuration of the reference electrode, the first working electrode, and the second working electrode.

[0017] The at least one wireless sensor may include one or more orientation sensors. The instructions may be configured to cause the at least one processor to: receive an output from the one or more orientation sensors; and determine the orientation of the at least one wireless EEG sensor based on the output. The one or more orientation sensors may include one or more of an accelerometer and a gyroscope.

[0018] In some implementations, the techniques described herein relate to a wireless electroencephalogram (EEG) sensor configured to detect brain activity. The wireless EEG sensor may include: a housing and a plurality of electrodes disposed on an exterior surface of the housing. The plurality of electrodes may include: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode. The second axis may be perpendicular relative to the first axis.

[0019] According to some implementations, the techniques described herein relate to a system for detecting brain activity. The system may include a plurality of wireless electroencephalogram (EEG) sensors. Each wireless EEG sensor can include a housing and a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals. The plurality of electrodes may include: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode. The second axis may be perpendicular to the first axis. The system may include a non-transitory computer-readable medium storing executable instructions that, when executed by at least one processor, cause the at least one processor to: receive EEG signals each of the plurality of wireless EEG sensors.

[0020] Also disclosed are methods of operating any of the sensors or systems disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the following description, various implementations will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the implementations. However, it will also be apparent to one skilled in the art that the implementations may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the implementation being described.

[0022] Figs. 1A-1C illustrate bottom views of wearable EEG recording wearable sensors.

[0023] Fig. ID illustrates a perspective view of a wearable EEG recording wearable sensor.

[0024] Fig. 2 illustrates a wearable EEG sensor on a scalp of a patient.

[0025] Fig. 3 illustrates a plurality of quadrant indicators.

[0026] Fig. 4 is an illustration of an EEG monitoring system.

[0027] Fig. 5A is an illustration of an EEG monitoring system.

[0028] Fig. 5B is an illustration of an EEG monitoring system.

[0029] Fig. 5C is an illustration of an EEG monitoring system.

[0030] Fig. 6 illustrates a method for determining the magnitude or direction of localized EEG signals collected by a wearable EEG sensor.

DETAILED DESCRIPTION

[0031] Described herein are improved systems, kits, and methods for EEG monitoring and seizure detection. Existing wired EEG systems, e.g. the 10-20 system, can be used to diagnose patients suffering from EEG disorders like epilepsy, sleep disorders, etc. Traditionally, wired EEG systems include approximately nineteen (19) active electrodes placed at various locations across the scalp of the patient and two (2) reference electrodes placed on the patient’s ears. The placement of the two reference electrodes on the ears of the patient provides a reference or ground for each of the active electrodes because the ears have almost no EEG signals or electromyographical (EMG) signals. The placement of the nineteen active electrodes across the scalp of the patient allows the wired system to detect seizures as they progress through or across brain regions.

[0032] However, existing wired EEG systems are not without significant downsides. The 10-20 system requires a patient to come to a hospital for several hours or days for monitoring. Each of the active electrodes must be glued to the patient’s scalp, and the patient must remain tethered to the 10-20 system until the monitoring period is over. Needless to say, the experience can be cumbersome and uncomfortable for the patient. These disadvantages are compounded by the fact that wired systems 10-20 are not readily available to most patients. It’s estimated that over 3.4 million people in the United States suffer from epilepsy. Patients living in rural and suburban areas often need to drive at least an hour for a monitoring session at a tertiary hospital facility.

[0033] Applicant has developed systems and methods for wireless EEG monitoring, such as the systems and methods described in U.S. Patent 11,020,035 (titled “Self- Contained EEG Recording System”), U.S. Patent 11,633,144 (titled “EEG Recording And Analysis”), and U.S. Patent 11,857,330 (titled “Systems And Methods For Electroencephalogram Monitoring”), each of which is incorporated by reference in its entirety. The wireless EEG sensors described in each of these publications provide significant advantages over the existing wired EEG systems. They can be easily placed and removed from the scalp of the patient. The EEG sensors provide for longer monitoring sessions without inhibiting the movement and freedom of the patient. Further, the EEG sensors enable remote monitoring sessions, making the technology widely available to rural and suburban patients without the need to schedule an appointment or travel to a healthcare facility.

[0034] In certain cases, the EEG sensors developed by Applicant can present technical challenges unique to their design and implementation. For instance, the EEG sensors may be too compact to allow placement of the reference electrode in a true EEG null location, such as an earlobe of the patient. In turn, the reference electrode of compact EEG sensors provides a local signal reference that, while effective, can prevent the EEG sensor from detecting the localized activity of EEG signals if the wireless sensor is not positioned or oriented correctly. For example, a reference electrode and active electrode of the EEG sensor may be oriented perpendicular to the direction of localized EEG signal development. Although the local signal activity may change the electrical potential at the active and reference electrodes, they both change together, so the difference in potential between the electrodes may not be detected. Conversely, if the local signal activity propagates parallel to the reference and active electrodes, the signal will be detected by the wireless EEG sensor.

[0035] Advantageously, implementations of an EEG sensor disclosed herein can detect a magnitude and direction of local EEG signals regardless of the sensor’s location or orientation. For example, a wireless EEG sensor or system may detect multidirectional localized EEG signals without artifacts caused by orientation effects. The wireless EEG sensors and systems described herein can determine the magnitude or direction of localized EEG signal agnostic of the orientation of the sensor. In some cases, the wireless EEG sensors and systems can capture an amplitude of localized EEG signals regardless of the orientation of the electrodes relative to the localized EEG signals. The wireless EEG sensors and systems may use a dual bipolar configuration to allow multidirectional local EEG signals to be detected. The dual bipolar configuration of the wireless EEG sensors or systems can capture a magnitude and direction of the localized EEG signals regardless of the orientation of the electrodes.

[0036] Further, the EEG sensor can detect the magnitude and direction of the local EEG signals while maintaining a discrete and compact form so that the EEG sensor can be worn for a long period of time without causing discomfort to the patient. Implementations of EEG sensors, EEG monitoring systems, and methods disclosed herein allow the magnitude or direction of local EEG signals to be detected without substantially increasing the size of the wireless EEG sensors. In addition to their comfort, wearability, and low-profile, the additional information provided by the EEG sensor can allow monitoring of time-dependent EEG waveforms as they propagate across the scalp of the patient, which can in turn provide more reliable and accurate detection of neurological events of interest. Further, the EEG sensor can allow for noise signals, particularly electromyographical (EMG) signals, to be more easily identified and removed from EEG signals. [0037] Fig. 1 A illustrates a bottom view of a wearable EEG sensor 100, which can be used to monitor EEG signals. The wearable sensor 100 may be self-contained in a housing 102. The sensor 100 may be an integrated EEG sensor, a unitary EEG sensor, or a self- contained EEG sensor. The housing 102 may be formed of a plastic, polymer, composite, or the like that is water-resistant, waterproof, or the like. The housing 102 may be square or rectangular as shown in Fig. 1A. The housing 102 may be circular as shown in Fig. IB or triangular as shown in Fig. 1C. The housing 102 may be an extended, rounded shape as shown in Fig. ID. The shape of the housing in Fig. ID can be referred to as a jellybean shape, and may facilitate accurate placement on a subject (or patient) in a correct orientation as well as promote patient comfort and prolonged wear. The housing 102 may be elliptical, pentagonal, hexagonal, octagonal, etc.

[0038] The housing 102 may contain all of the electronics for recording EEG signals from at least two active electrodes 104, 106 and a reference electrode 108. In some cases, the sensor 100 may be referred to as a “dual -bipolar” sensor. The active electrodes 104, 106 may also be referred to as working electrodes. The electrodes 104, 106, and 108 may be formed of any suitable material. For example, the electrodes 104, 106, and 108 may comprise gold, silver, silver-silver chloride, carbon, combinations of the foregoing, or the like.

[0039] The electrodes 104, 106, and 108 can be positioned on the bottom, scalpfacing side of the wearable EEG sensor 100. The first active electrode 104 may be placed a distance away from the reference electrode 108 along a first axis 110, and the second active electrode 106 may be placed a distance away from the reference electrode 108 along a second axis 112. The first axis 110 may be a line formed between the center of the first active electrode 104 and the center of the reference electrode 108. Similar to the first axis 110, the second axis 112 may be a line formed between the center of the second active electrode 106 and the center of the reference electrode 108. The first axis 110 and the second axis 112 intersect at the reference electrode 108, forming an angle 114. In some implementations, the first axis 110 and the second axis 112 are substantially perpendicular, and the angle 114 may be about 90 degrees. In other examples, the angle may be between about 0 degrees and about 180 degrees.

[0040] The distance between each of the active electrodes 104, 106 and the reference electrode 108 may be measured between the center of each electrode (a center-to- center distance) or from the closest edge of each electrode (an edge-to-edge distance). The center-to-center distance between the active electrodes 104, 106 and the reference electrode 108 may be about 10 millimeters (mm) to about 40 mm. For example, the center-to-center distance may be less than 30 mm, less than 20mm, about 18mm, etc. The edge-to-edge distance between the active electrodes 104, 106 and the reference electrode 108 may be about 1 mm to about 30 mm. For example, the edge-to-edge distance may be less than 20 mm, less than 15 mm, less than 10 mm, etc. The distance between the first active electrode 104 and the reference electrode 108 (center-to-center or edge-to-edge) may be the same as the distance between the first active electrode 106 and the reference electrode 108.

[0041] The wearable EEG sensor 100 may be placed at a location on a scalp of a patient, such as behind an ear of the patient as shown in Fig. 2. The location may be behind a left ear of the patient, behind a right ear of the patient, on a left forehead of the patient, or on a right forehead of the patient. In some cases, multiple wearable EEG sensors 100 can be placed in multiple locations on the scalp of the patients, such as behind a left ear of the patient, behind a right ear of the patient, on a left forehead of the patient, or on a right forehead of the patient. Placement of the EEG sensor(s) 100 may be informed or guided by previous diagnostic procedures or analyses thereof.

[0042] The first active electrode 104 and the second active electrode 106 may monitor EEG activity at the location on the scalp of the patient, including EEG activity indicative of a seizure. The first active electrode 104 may measure a first EEG signal along the first axis 110 relative to the reference electrode 108, and the second active electrode 106 may measure a second EEG signal along the second axis 112 relative to the reference electrode 108. The first EEG signal may be represented as a difference in electrical potential between the first active electrode 104 and the reference electrode 108. Similarly, the second EEG signal may be represented as a difference in electrical potential between the second active electrode 106 and the reference electrode 108.

[0043] The wearable EEG sensor 100 includes electronic circuitry (not shown) that is supported by the housing 102, such as enclosed in the housing. The electronic circuitry can be configured to process the first and second EEG signals detected the first and second active electrodes 104, 106, respectively. The electronic circuitry may generate a processed EEG signal based on the first EEG signal and the second EEG signal. The processed EEG signal may be an EEG vector representing a magnitude and direction of local EEG activity. [0044] The electronic circuitry may determine the magnitude of the EEG vector based on the first EEG signal, the second EEG signal, a direction of the first axis 110, a direction of the second axis 112, or the angle between the axes 110, 112. The magnitude (EEGM) may be provided as a single, scalar quantity. For example, the angle 114 may be a right angle, i.e. 90 degrees. The electronic circuitry may receive the first EEG signal and the second EEG signal and determine the EEG vector magnitude using the following equation:

EEG_M = ]EEG_x ² + EEG ² (1)

In Equation 1, EEGxmay represent the first EEG signal, EEGy may represent the second EEG signal, and EEGM may represent the magnitude of the EEG vector processed EEG signal. For example, EEGx and EEGy may represent an amplitude, scalar value, or an average thereof of the first and second EEG signals, respectively.

[0045] In another example, the angle 114 may be less than or greater than 90 degrees. The electronic circuitry may determine the EEG vector magnitude using the following equation:

EEG_M = EEG_x ² + EEG-² — EEG_xEEG_y cos(a) (2)

In Equation 2, EEGx may represent the first EEG signal, EEGy may represent the second EEG signal, EEG may represent the magnitude of the EEG vector processed EEG signal, and alpha (a) may represent the angle 114. For example, EEGx and EEGy may represent an amplitude, scalar value, or an average thereof of the first and second EEG signals, respectively. The term being subtracted in Equation 2 may represent the projection of the EEG vector. The angle 114 may be an angle other than 180 degrees.

[0046] In some implementations, the electronic circuitry may determine a direction of the EEG vector based on the first EEG signal and the second EEG signal. The electronic circuitry may determine the direction based on whether the first EEG signal is positive or negative value and whether the second EEG signal is positive or negative value. The electronic circuitry may assign a quadrant indicator based on whether the first EEG signal (EEGx) is positive or negative and whether the second EEG signal (EEGy) is positive or negative. Fig. 3 illustrates a plurality of example quadrant indicators. A first quadrant 302 may correspond with a negative first EEG signal value and a positive second EEG signal value. A second quadrant 304 may correspond with a negative first EEG signal value and a negative second EEG signal value. A third quadrant 306 may correspond with a positive first EEG signal value and a negative second EEG signal value. A fourth quadrant 308 may correspond with a positive first EEG signal value and a positive second EEG signal value. For example, suppose that the first and second EEG signals have a positive value. The electronic circuitry may assign the fourth quadrant 308 as the quadrant indicator.

[0047] The direction of the EEG signal may be defined as an angle relative to the first axis. For example, the direction of the EEG signal may be determined based on the following equation:

In Equation 3, EEGxmay represent the first EEG signal, EEG_y may represent the second EEG signal, and alpha (a) may represent an angle between the combined EEG signal and the first axis. The electronic circuitry may determine the direction based on the quadrant indicator and the angle (a).

[0048] In some implementations, the electronic circuitry may determine the direction of the EEG vector based on the first EEG signal, the second EEG signal, the location of the wearable EEG sensor 100 on a scalp of a patient, or the orientation of the sensor 100. The electronic circuitry may assign a quadrant indicator based on whether the first EEG signal is positive or negative and whether the second EEG signal is positive or negative. The electronic circuitry may determine the direction of the EEG vector based on the quadrant indicator and the location and orientation of the wearable EEG sensor 100.

[0049] Based on the location and orientation of the wearable EEG sensor 100, the electronic circuitry may determine anatomical directions associated with each of the quadrant indicators. For example, the wearable EEG sensor 100 may be placed behind the ear of a patient as shown in Fig. 2. The first EEG signal and the second EEG signal may both be positive values, and the electronic circuitry may determine that the quadrant indicator is the fourth quadrant. Using the location and orientation of the wearable EEG sensor 100, the electronic circuitry may determine the second quadrant is associated with a superior-longitudinal direction. [0050] The wearable EEG sensor 100 may include one or more orientation sensors. For example, the one or more orientation sensors may include an accelerometer or gyroscope. The electronic circuitry may determine the orientation of the wearable EEG sensor 100 based on the data collected by the one or more orientation sensors. The location or the orientation of the wearable EEG sensor 100 may be provided to the electronic circuity, e.g. by a remote computing device. The location or orientation of the wearable EEG sensor 100 may be determined based on a setup process for the wearable EEG sensor 100 such as those systems and methods described in International Publication No. WO 2024/086170, which is incorporated by reference in its entirety.

[0051] The electronic circuitry may process the first EEG signal, the second EEG signal, or the EEG vector based on one or more of the direction of the EEG vector, the location of the wearable EEG sensor 100, or the orientation of the sensor 100 according to some implementations. For example, the electronic circuitry may identify one or more noise signals associated with the location and orientation of the sensor such as local electromyographical (EMG) signals. The electronic circuitry may identify the noise signals based on a directionality of the noise signals or a consistency of the noise signals. The electronic circuitry may apply one or more filters to the first EEG signal, the second EEG signal, or the EEG vector to remove the noise signals. The one or more filters may be notch filter(s), high pass filter(s), low pass filter(s), etc.

[0052] In some implementations, the sensor 100 may be placed in electronic communication with a local device, such as a tablet or smart watch, or a remote computing device. The local device or the remote computing device may periodically or continuously receive the first EEG signal, the second EEG signal, or the EEG vector from the sensor 100. The local device or the remote computing device may identify one or more noise signals associated with the location and orientation of the sensor 100. The local device or the remote computing device may apply one or more filters to the first EEG signal, the second EEG signal, or the EEG vector to remove the noise signals.

[0053] For example, the wearable EEG sensor 100 may be placed above the patient’s left eye such that first axis 110 extends longitudinally and the second axis 112 extends transversely. The electronic circuitry may identify one or more noise signals associated with the patient blinking and apply one or more filters to remove those noise signals. The electronic circuitry may determine that the blinking noise signals occur along the first axis. The electronic circuitry may determine a frequency associated with the blinking noise signals and apply a filter to the first EEG signal to remove them.

[0054] In some cases, the wearable EEG sensor 100 includes a power source supported by the housing and configured to provide power to the electronic circuitry. In some cases, the wearable EEG sensor 100 includes a rechargeable battery. The wearable EEG sensor 100 can be designed to be a self-contained or integrated sensor that is one-time limited use per user and disposable. The wearable EEG sensor 100 may include additional active electrodes, e.g. three active electrodes, four active electrodes, five active electrodes, etc. In some implementations, the wearable EEG sensor 100 may include one or more additional sensors such as an accelerometer, a gyroscope, a PPG sensor, a differential PPG sensor, a skin chemistry sensor, a temperature sensor, etc. The wearable EEG sensor 100 may be packaged such that removal from the package activates the circuitry.

[0055] The wearable EEG sensor 100 can be placed anywhere on the scalp as placing a conventional wired EEG electrode. The wearable EEG sensor 100 can self-adhere to the scalp either through a conductive attachment, an attachment with a conductive, or through mechanical means, such as intradermal fixation with a memory-shape metal, or the like.

[0056] In some implementations, the wearable EEG sensor 100 may be a part of an EEG monitoring system, such as the EEG monitoring system 400 shown in Fig. 4. The wearable EEG sensor 100 can be used alone or in combination with other wearable EEG sensors 100 as part of the plurality of wearable EEG sensors 401 (for instance, four wearable EEG sensors). The wearable EEG sensor 100 or the plurality of wearable EEG sensors 401 can be used as a discrete tool to monitor EEG signals.

[0057] The wearable EEG sensor 100 may be configured to wirelessly communicate processed EEG signal to a remote computing device 402. For example, the electronic circuitry may transmit the processed EEG signal to the remote computing device using Bluetooth Low Energy (BLE) protocol or another suitable protocol. The remote computing device 402 can be a portable computing device as described herein. The remote computing device 402 may receive the processed EEG signal from the electronic circuitry and perform additional processing of the EEG signal to identify potential seizure events. The electronic circuitry may provide the first EEG signal and the second EEG signal to the portable computing device, and the portable computing device may perform one or more of the functions of the electronic circuitry described above. The system 400 can include software to assist a user in setting up the system. The user may be a healthcare provider or a patient.

[0058] The portable computing device 402 can include communication functionality, such as wireless communication functionality. The portable computing device 402 can be configured for being worn by the user. The portable computing device 402 can include a wearable device with a display such as a smartwatch or smartphone, or a wearable device without a display such as a smart band, smart jewelry, or the like. The portable computing device 402 can include a tablet or another computing device, such as medical grade tablet with a larger display than the wearable device. The portable computing device 402 may connect to a remote computing device 404 (which can be a cloud service) through a network, such as the Internet. The remote computing device 404 can include one or more computing devices, such as servers.

[0059] Patient EEG data collected by the plurality of wearable sensors 401 may include a plurality of EEG data channels. In some implementations, the discrete wireless EEG sensors may collect the patient EEG data independently and without reference to one another. Each EEG sensor may independently provide the EEG data channel to one or more portable computing devices where the plurality of EEG data channels may be compiled to form patient EEG data. The portable computing device 402 or the remote computing device 404 may process and analyze the patient EEG data to identify seizure events.

[0060] Fig. 5A illustrates an EEG monitoring system 500. The EEG monitoring system 500 may include at least one wireless EEG sensor 502. The wireless EEG sensor 502 may be similar to the sensor 100. The wireless EEG sensor 502 may include a first active electrode 504, a second active electrode 506, and a reference electrode 508. The first active electrode 504 may be placed a distance away from the reference electrode 508 along a first axis 510, and the second active electrode 506 may be placed a distance away from the reference electrode 508 along a second axis 512. The first axis 510 and the second axis 512 intersect at the reference electrode 508, forming an angle 514.

[0061] Fig. 5B illustrates an EEG monitoring system 516. The EEG monitoring system 516 can include at least two wireless EEG sensors 502. Fig. 5C illustrates an EEG monitoring system 518. The EEG monitoring system 518 can include at least four wireless EEG sensors 502.

[0062] Fig. 6 illustrates a method 600 for determining the magnitude or direction of localized EEG signals collected by a wearable EEG sensor. The method 600 may be performed by an EEG monitoring system such as the system 400. In some implementations, the method may include more or fewer steps. The steps may be performed in a different order or simultaneously.

[0063] The method 600 may begin at step 602 where one or more processors, such as the at least one processor of the portable computing device 402, may provide instructions for placing at least one wireless EEG sensor, such as the wearable EEG sensor 100, on a scalp of a patient. For example, the location may be behind a left ear of the patient, behind a right ear of the patient, on a left forehead of the patient, or on a right forehead of the patient.

[0064] After one or more wearable EEG sensors 100 have been placed on the scalp, the method 600 may move to step 604 where the wearable EEG sensor(s) 100 may collect EEG signals along a first axis and along a second axis. As discussed above, the wearable EEG sensor 100 may include a first active electrode placed a distance away from a reference electrode along a first axis and a second active electrode may be placed a distance away from the reference electrode along a second axis. The first active electrode may measure a first EEG signal along the first axis relative to the reference electrode, and the second active electrode may measure a second EEG signal along the second axis relative to the reference electrode.

[0065] The method 600 may move to step 606 where a magnitude of the EEG signal monitored by the wearable EEG sensor 100 may be determined based on the EEG signals collected along the first and second axes. The magnitude of the EEG signal may be determined by one or more components of an EEG monitoring system, such as the electronic circuitry of the wearable EEG sensor 100, the portable computing device 402 or the remote computing device 404.

[0066] As described herein, the magnitude of the EEG signal may be determined based on the first EEG signal, the second EEG signal, and the angle between the axes. The magnitude (EEGM) may be provided as a single, scalar quantity. For example, if the angle between the first and second axes is 90 degrees, the magnitude of the EEG signal magnitude may be determined using Equation 1. In another example, if the angle between the first and second axes is not 90 degrees, and the magnitude of the EEG signal may be determined using Equation 2.

[0067] The method 600 may move to step 608 where a direction of the EEG signal may be determined. As with the magnitude of the EEG signal, the direction may be determined by one or more components of an EEG monitoring system, such as the electronic circuitry of the wearable EEG sensor 100, the portable computing device 402 or the remote computing device 404.

[0068] The direction of the EEG signal may be determined based on the first EEG signal and the second EEG signal. The direction of the local EEG signal may be determined based on whether the first EEG signal is positive or negative value and whether the second EEG signal is positive or negative value. As described herein, a quadrant indicator may be assigned based on whether the first EEG signal is positive or negative and whether the second EEG signal is positive or negative.

[0069] The direction of the EEG signal may be determined based on the first EEG signal, the second EEG signal, the location of the at least one wireless EEG sensor on a scalp of a patient, or the orientation of the sensor. A quadrant indicator may be assigned based on whether the first EEG signal is positive or negative and whether the second EEG signal is positive or negative. In some cases, the direction of the local EEG signal may be determined based on the quadrant indicator, the location of the sensor, and the orientation of the sensor, as described herein. In some cases, the direction of the EEG signal may be determined using Equation 3 as described above.

[0070] For example, the at least one wireless EEG sensor may be placed on a left forehead of the patient. Based on the location and orientation of the sensor, each of the quadrant indicators may be associated with corresponding anatomical directions. For example, the first EEG signal and the second EEG signal may both be positive values, and the electronic circuitry may determine that the quadrant indicator is the fourth quadrant. Using the location and orientation of the sensor 100, the electronic circuitry may determine the second quadrant is associated with a left-transverse direction. Example Implementations

[0071] Clause 1. A wireless electroencephalogram (EEG) sensor configured to detect brain activity, the wireless EEG sensor comprising: a housing; a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode and configured to monitor a first EEG signal along the first axis; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode and configured to monitor a second EEG signal along the second axis; and an electronic circuitry supported by the housing and configured to process the EEG signals detected by the plurality of electrodes, the electronic circuitry further configured to: determine a magnitude of a combined EEG signal based on the first EEG signal and the second EEG signal.

[0072] Clause 2. The wireless EEG sensor of any one of the preceding clauses, wherein the plurality of electrodes are further configured to monitor the EEG signals along the first axis and the second axis to enable EEG activity to be detected regardless of an orientation of the housing.

[0073] Clause 3. The wireless EEG sensor of any one of the preceding clauses, wherein the electronic circuitry is further configured to determine a direction of the combined EEG signal based on the first EEG signal, the second EEG signal, and an arrangement of the reference electrode, the first working electrode, and the second working electrode.

[0074] Clause 4. The wireless EEG sensor of clause 3, wherein the direction comprises an angle between the combined EEG signal and the first axis.

[0075] Clause 5. The wireless EEG sensor of any one of the preceding clauses, wherein a first distance between the first working electrode and the reference electrode is equal to or less than 30 millimeters, and wherein a second distance between the second working electrode and the reference electrode is equal to or less than 30 millimeters.

[0076] Clause 6. The wireless EEG sensor of clause 5, wherein the first distance and the second distance are equal to or less than 20 millimeters.

[0077] Clause 7. The wireless EEG sensor of clause 6, wherein the first distance and the second distance are equal to about 18 millimeters. [0078] Clause 8. The wireless EEG sensor of any one of the preceding clauses, wherein the wireless EEG sensor is a dual-bipolar sensor.

[0079] Clause 9. The wireless EEG sensor of any one of the preceding clauses, wherein the second axis is perpendicular to the first axis.

[0080] Clause 10. A system for detecting brain activity, the system comprising: at least one wireless electroencephalogram (EEG) sensor, the at least one wireless EEG sensor comprising: a housing; and a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode and configured to monitor a first EEG signal along the first axis; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode and configured to monitor a second EEG signal along the second axis; and a non-transitory computer-readable medium storing executable instructions that, when executed by at least one processor, cause the at least one processor to: receive the first EEG signal and the second EEG signal from the at least one wireless EEG sensor; and determine a magnitude of a combined EEG signal based on the first EEG signal and the second EEG signal.

[0081] Clause 11. The system of clause 10, wherein the at least one wireless EEG sensor is further configured to monitor EEG activity regardless of an orientation of the housing.

[0082] Clause 12. The system of any one of clauses 10 to 11, wherein the magnitude of the combined EEG signal is represented as a single scalar quantity.

[0083] Clause 13. The system of any one of clauses 10 to 12, wherein the executable instructions further cause the at least one processor to determine a direction of the combined EEG signal based on the first EEG signal and the second EEG signal.

[0084] Clause 14. The system of any one of clauses 10 to 13, wherein a first distance between the first working electrode and the reference electrode is equal to or less than 30 millimeters, and wherein a second distance between the second working electrode and the reference electrode is equal to or less than 30 millimeters.

[0085] Clause 15. The system of clause 14, wherein the first distance and the second distance are equal to or less than 20 millimeters. [0086] Clause 16. The system of clause 15, where in the first distance and the second distance are equal to about 18 millimeters.

[0087] Clause 17. The system of any one of clauses 10 to 16, wherein the executable instructions further cause the at least one processor to: provide instructions for placing the housing on a scalp of a patient.

[0088] Clause 18. The system of clause 17, wherein the executable instructions further cause the at least one processor to: determine a direction of the combined EEG signal based on the EEG signals and a location and an orientation of the housing on the scalp of the patient.

[0089] Clause 19. The system of clause 18, wherein the at least one wireless EEG sensor further comprises one or more orientation sensors, and wherein the executable instructions further cause the at least one processor to: receive an output from the one or more orientation sensors; and determine the orientation of the housing based on the output.

[0090] Clause 20. The system of clause 19, wherein the one or more orientation sensors further comprise one or more of: an accelerometer and a gyroscope.

[0091] Clause 21. The system of any one of clauses 10 to 20, wherein the second axis is perpendicular to the first axis.

[0092] Clause 22. A wireless electroencephalogram (EEG) sensor configured to detect brain activity, the wireless EEG sensor comprising: a housing; and a plurality of electrodes disposed on an exterior surface of the housing, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode.

[0093] Clause 23. The wireless EEG sensor of clause 22, wherein the second axis is perpendicular relative to the first axis.

[0094] Clause 24. The wireless EEG sensor of any one of clauses 22 to 23, wherein: the first working electrode is configured to monitor a first EEG signal; the second working electrode is configured to monitor a second EEG signal; and a magnitude of a combined EEG signal is determined based on the first EEG signal and the second EEG signal.

[0095] Clause 25. A system for detecting brain activity, the system comprising: a plurality of wireless electroencephalogram (EEG) sensors, each wireless EEG sensor comprising: a housing; and a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode, the first working electrode configured to monitor a first EEG signal; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode, the second working electrode configured to monitor a second EEG signal; and a non-transitory computer-readable medium storing executable instructions that, when executed by at least one processor, cause the at least one processor to: receive EEG signals each of the plurality of wireless EEG sensors; and determine magnitudes of a plurality of combined EEG signals based on a first EEG signal and a second EEG signal received from each wireless EEG sensor.

[0096] Clause 26. The system of clause 25, wherein the second axis is perpendicular to the first axis.

Other Variations

[0097] Any of the wireless EEG sensors described herein can be discrete, unitary, integrated, or self-contained. The general principles described herein may be extended to other scenarios. For example, for intensive care in pediatric and adults two sensors, four sensors, eight sensors, or various combination of sensors may be used.

[0098] Various other configurations are may also be used, with particular elements that are depicted as being implemented in hardware may instead be implemented in software, firmware, or a combination thereof. One of ordinary skill in the art will recognize various alternatives to the specific embodiments described herein.

[0099] The specification and figures describe particular embodiments which are provided for ease of description and illustration and are not intended to be restrictive. Embodiments may be implemented to be used in various environments without departing from the spirit and scope of the disclosure.

[0100] At least some elements of implementations of one or more disclosed devices of the can be controlled and at least some steps of implementations of one or more disclosed methods can be effectuated, in operation with a programmable processor governed by instructions stored in a memory. The memory may be random access memory (RAM), read- only memory (ROM), flash memory or any other memory, or combination thereof, suitable for storing control software or other instructions and data. Those skilled in the art should also readily appreciate that instructions or programs defining the functions of the disclosed implementations may be delivered to a processor in many forms, including, but not limited to, information permanently stored on non-writable storage media (for example read-only memory devices within a computer, such as ROM, or devices readable by a computer I/O attachment, such as CD-ROM or DVD disks), information alterably stored on writable storage media (for example floppy disks, removable flash memory and hard drives) or information conveyed to a computer through communication media, including wired or wireless computer networks. In addition, while some implementations may be embodied in software, the functions necessary to implement the disclosed features may optionally or alternatively be embodied in part or in whole using firmware and/or hardware components, such as combinatorial logic, Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs) or other hardware or some combination of hardware, software and/or firmware components.

[0101] In various embodiments, input from a user may be requested. Examples of methods for receiving user input, such as receiving a button press from a user, are illustrative and not by means of limitation. Alternative methods of receiving user input may be used, including receiving a button press on a touch screen, a physical button press on a device, a swipe, a tap, any other touch gestures, a spoken (audio) input, etc.

[0102] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

[0103] Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0104] Depending on the embodiment, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, can be added, merged, or left out altogether. Moreover, in certain embodiments, operations or events can be performed concurrently, for example, through multi-threaded processing, interrupt processing, or multiple processors or processor cores or on other parallel architectures, rather than sequentially.

[0105] The various illustrative logical blocks, modules, routines, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, in executable software stored on a non-transitory storage medium, or as a combination of electronic hardware and executable software. To clearly illustrate this interchangeability, various illustrative components, blocks, modules, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, or as software that runs on hardware, depends upon the particular application and design constraints imposed on the overall system. The described functionality can be implemented in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the disclosure.

[0106] Moreover, the various illustrative logical blocks and modules disclosed herein can be implemented or performed by a machine, such as a machine learning service server, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein.

[0107] The elements of a method, process, routine, or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of a non-transitory computer-readable storage medium. [0108] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “for example,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.

[0109] Disjunctive language such as the phrase “at least one of X, Y, or Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (for example, X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present.

[0110] Unless otherwise explicitly stated, articles such as “a” or “an” should generally be interpreted to include one or more described items. Accordingly, phrases such as “a device configured to” are intended to include one or more recited devices. Such one or more recited devices can also be collectively configured to carry out the stated recitations. For example, “a processor configured to carry out recitations A, B and C” can include a first processor configured to carry out recitation A working in conjunction with a second processor configured to carry out recitations B and C.

[oni] While the above detailed description has shown, described, and pointed out novel features as applied to various embodiments, it can be understood that various omissions, substitutions, and changes in the form and details of the devices or algorithms illustrated can be made without departing from the spirit of the disclosure. As can be recognized, certain embodiments described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others. The scope of certain embodiments disclosed herein is indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

WHAT IS CLAIMED IS:

1. A wireless electroencephalogram (EEG) sensor configured to detect brain activity, the wireless EEG sensor comprising: a housing; a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode and configured to monitor a first EEG signal along the first axis; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode and configured to monitor a second EEG signal along the second axis; and an electronic circuitry supported by the housing and configured to process the EEG signals detected by the plurality of electrodes, the electronic circuitry further configured to: determine a magnitude of a combined EEG signal based on the first EEG signal and the second EEG signal.

2. The wireless EEG sensor of any one of the preceding claims, wherein the plurality of electrodes are further configured to monitor the EEG signals along the first axis and the second axis to enable EEG activity to be detected regardless of an orientation of the housing.

3. The wireless EEG sensor of any one of the preceding claims, wherein the electronic circuitry is further configured to determine a direction of the combined EEG signal based on the first EEG signal, the second EEG signal, and an arrangement of the reference electrode, the first working electrode, and the second working electrode.

4. The wireless EEG sensor of claim 3, wherein the direction comprises an angle between the combined EEG signal and the first axis.

5. The wireless EEG sensor of any one of the preceding claims, wherein a first distance between the first working electrode and the reference electrode is equal to or less than 30 millimeters, and wherein a second distance between the second working electrode and the reference electrode is equal to or less than 30 millimeters.

6. The wireless EEG sensor of claim 5, wherein the first distance and the second distance are equal to or less than 20 millimeters.

7. The wireless EEG sensor of claim 6, wherein the first distance and the second distance are equal to about 18 millimeters.

8. The wireless EEG sensor of any one of the preceding claims, wherein the wireless EEG sensor is a dual-bipolar sensor.

9. The wireless EEG sensor of any one of the preceding claims, wherein the second axis is perpendicular to the first axis.

10. A system for detecting brain activity, the system comprising: at least one wireless electroencephalogram (EEG) sensor, the at least one wireless EEG sensor comprising: a housing; and a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode and configured to monitor a first EEG signal along the first axis; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode and configured to monitor a second EEG signal along the second axis; and a non-transitory computer-readable medium storing executable instructions that, when executed by at least one processor, cause the at least one processor to: receive the first EEG signal and the second EEG signal from the at least one wireless EEG sensor; and determine a magnitude of a combined EEG signal based on the first EEG signal and the second EEG signal.

11 . The system of claim 10, wherein the at least one wireless EEG sensor is further configured to monitor EEG activity regardless of an orientation of the housing.

12. The system of any one of claims 10 to 11, wherein the magnitude of the combined EEG signal is represented as a single scalar quantity.

13. The system of any one of claims 10 to 12, wherein the executable instructions further cause the at least one processor to determine a direction of the combined EEG signal based on the first EEG signal and the second EEG signal.

14. The system of any one of claims 10 to 13, wherein a first distance between the first working electrode and the reference electrode is equal to or less than 30 millimeters, and wherein a second distance between the second working electrode and the reference electrode is equal to or less than 30 millimeters.

15. The system of claim 14, wherein the first distance and the second distance are equal to or less than 20 millimeters.

16. The system of claim 15, where in the first distance and the second distance are equal to about 18 millimeters.

17. The system of any one of claims 10 to 16, wherein the executable instructions further cause the at least one processor to: provide instructions for placing the housing on a scalp of a patient.

18. The system of claim 17, wherein the executable instructions further cause the at least one processor to: determine a direction of the combined EEG signal based on the EEG signals and a location and an orientation of the housing on the scalp of the patient.

19. The system of claim 18, wherein the at least one wireless EEG sensor further comprises one or more orientation sensors, and wherein the executable instructions further cause the at least one processor to: receive an output from the one or more orientation sensors; and determine the orientation of the housing based on the output.

20. The system of claim 19, wherein the one or more orientation sensors further comprise one or more of: an accelerometer and a gyroscope.

21. The system of any one of claims 10 to 20, wherein the second axis is perpendicular to the first axis.

22. A wireless electroencephalogram (EEG) sensor configured to detect brain activity, the wireless EEG sensor comprising: a housing; and a plurality of electrodes disposed on an exterior surface of the housing, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode.

23. The wireless EEG sensor of claim 22, wherein the second axis is perpendicular relative to the first axis.

24. The wireless EEG sensor of any one of claims 22 to 23, wherein: the first working electrode is configured to monitor a first EEG signal; the second working electrode is configured to monitor a second EEG signal; and a magnitude of a combined EEG signal is determined based on the first EEG signal and the second EEG signal.

25. A system for detecting brain activity, the system comprising: a plurality of wireless electroencephalogram (EEG) sensors, each wireless EEG sensor comprising: a housing; and a plurality of electrodes disposed on an exterior surface of the housing and configured to detect EEG signals, the plurality of electrodes comprising: a reference electrode; a first working electrode disposed on a first axis connecting the first working electrode to the reference electrode, the first working electrode configured to monitor a first EEG signal; and a second working electrode disposed on a second axis connecting the second working electrode and the reference electrode, the second working electrode configured to monitor a second EEG signal; and a non-transitory computer-readable medium storing executable instructions that, when executed by at least one processor, cause the at least one processor to: receive EEG signals each of the plurality of wireless EEG sensors; and determine magnitudes of a plurality of combined EEG signals based on a first EEG signal and a second EEG signal received from each wireless EEG sensor.

26. The system of claim 25, wherein the second axis is perpendicular to the first axis.