DE102008052406A1 - Method and device for detecting parameters for characterizing movements on the human or animal body - Google Patents

Abstract

The invention relates to a bending sensor for detecting functional parameters for characterizing movements on the human or animal body. The bending sensor comprises a fastening element 20, in particular a fastening plaster, for attaching the bending sensor to the skin of the human or animal body. Furthermore, a bending-sensitive detector 10 is provided for detecting bending parameters of the bending sensor. The detected bending parameters such as the bending angle, the bending speed and / or the bending acceleration are stored in a data memory 30. The fastener is stretchable and has a stretchable cavity for receiving a sensor of the detector. The sensor is fixed to a reference point of the fastener in the cavity.

Description

The The present invention relates to a method for detecting functional parameters for the characterization of movements of the human or animal body and a bending sensor for performing the method.

back pain are more or less severe pain of the human back, the whole may have different causes. Doctors speak of Dorsalgia or lumbar pain in affecting the lumbar-sacral region is. Probably the most common Occasion for Dorsalgia is a dysfunction of the joints in the area The spine. However, about 90% of all chronic (relapsing or persistent) back pain unspecific - d. h .: in the context of medical Investigations are ultimately no findings that the Explain complaints adequately. Currently you can Movement functions, for example for the treatment of unspecific back pain can not be objectively recorded. Only structural findings on imaging Diagnostic procedures are common (but with unspecific back pain do not grab).

It It is therefore an object of the present invention to provide a device which allows functional parameters for the characterization of motion sequences on the human or animal body to detect nonspecific or chronic complaints recorded motion patterns can be assigned. The detection of the bending information should be done primarily in the lumbar spine, as the cause for one large part all back pain you can see.

The Measuring dynamic function parameters is an untapped, but very important field in spinal medicine. The bending sensor according to the invention creates the opportunity Insight into everyday life, the function, the mobility, and the frequency of movement to get. The detection of motion parameters by means of the bending sensor according to the invention can for Orthopedics and spine medicine be seen as an analogue to the long-term ECG.

The The task is performed by the bending sensor to capture functional parameters for the characterization of movements of the human or animal body according to the appended claim 1 solved. The bending sensor comprises a fastening element, in particular a Fixing plaster, for fixing the bending sensor on the skin of the human or animal body. Further, a bending-sensitive detector for detecting bending parameters provided the bending sensor. The recorded bending parameters such as the bending angle, the bending speed and / or the bending acceleration are stored in a data store. The fastener is extensible and has a stretchable cavity for receiving a Sensor of the detector. The sensor is on one Reference point of the fastener fixed in the cavity.

One Sensor or sensor or sensor is a technical component, the specific physical or chemical properties as a quantitative measure can capture. These sizes will be in processable sizes (usually electrical signals) converted.

Of the bending sensor according to the invention should capture, for example, the flexion of the back. With bend becomes the deformation of a body under a load that is perpendicular to a body axis acts. To capture the dynamics of motion sequences on the human body (for example, on the back in the lumbar spine) one or more sensors by means of a fastener, in particular a fixing plaster, in an appropriate position be attached to the skin. The flexion of the back causes stretching of the skin. Elongation is the relative dimensional change (extension or shortening) of a body under pressure. When the size of the body increases, one speaks from a positive stretch, otherwise from a negative stretch or compression. The stretch of the skin when flexing the back is about 50% change in length in the area of the lumbar spine in a flexion movement. The fastener must therefore be stretchable be so that it is not due to the illustrated change in length of the skin dissolves. The sensors are made by means of elastic fasteners on the human skin (preferably left and right of the spine to Detection of back movements) fixed. Here the sensor band is only with a reference point connected to the fastener and slides free otherwise within the cavity provided by the fastener. The cavity forms as it were a guide channel, wherein the sensor though on the body is held to understand its inflection, but without the change in length to understand the skin.

Preferably, the fastener has an elastic lower layer with biocompatible thermally activatable adhesive layer for application to the skin. In addition, an elastic upper layer is provided such that the cavity is formed between the upper layer and the lower layer. The cavity is therefore not a rigid body but its shape and extent depends on the integrated sensor and the condition of the elas from the upper and lower classes. However, the upper and lower layers ensure that the sensor is held to a body, for example the back, in such a way that it tracks its flexion without being affected by the corresponding change in length of the skin.

One preferred embodiment the bending sensor according to the invention includes a sensor having a light guide. Of the Optical fiber has a transfer function, depending on changed by a bending of the light guide. Optical fibers are cables for the transmission of Light in the visible, ultraviolet or infrared range. examples for Optical fibers are optical fibers, glass fibers, polymeric optical Fibers or other optical components made of plastic and fiber optic components. Each optical fiber has a transfer function. The transfer function of a light guide describes the relationship between input and output Output signal for different frequencies of the injected light. The bend of the light guide leads that the transfer function changes, the is called, a curved light pipe couples less light relative to the light source Input signal as an unbent light guide. By determination the transfer function can thus the bending of the light guide can be determined.

The For example, coupling out light can be at the ends of the fibrous light guide respectively. Based on the decoupled light should be detected whether and how much the light guide is bent; but it is not readily possible to detect a bending direction of the light guide. Therefore owns the light guide preferably an additional lateral opening to Uncoupling light. The opening is on the surface of the light guide. As an opening in particular, a pointed depression or notch be provided. The side opening represents a scattering point that continues to open at bend or closed, so that the light output at the end of the fiber elevated or reduced (linear signal for positive and negative bending direction). Furthermore, through the side opening determine where the measured bend occurs, d. H. the bend can be spatially resolved be recorded. Preferably, a plurality of parallel Optical fiber with lateral openings provided on different segments used to capture the bend in different locations can be.

According to one preferred embodiment of present invention, the sensor has one or more Strain gauges. Strain gages (DMS) are measuring devices for the detection of distending deformations. They change even at low deformations their impedance and are used as strain sensors.

The electrical impedance of the strain gauge changes with a stretch or contraction of the strain gauge. By measurement the impedance, in particular the electrical resistance, the Extent of change in length of the strain gauge are determined. If the strain gauge as provided by the invention in a guide channel forming cavity on the examination object, for example, the back, housed is, leads one spinal flexion to a corresponding bend of the strain gauge, whereby the strain gauge changes its length.

Of the bending sensor according to the invention preferably comprises a detector comprising a detection device having. The detection device detects a change in the electrical impedance of the strain gauge or a change the transfer function of the light guide. Thus, the bending sensor has a measure of the bend of the examination object.

Of the Detector of the bending sensor according to the invention preferably has a tensile and elastically bendable substrate, on which the sensor is attached. The substrate should ensure that optionally occurring tensile or compressive stresses no change in length of the strain gauge. Because such a change in length otherwise falsely as a measure of the bend of the examination subject are misinterpreted. A suitable one Substrate, which allows a bend but the extension or Compression of the strain gauge is prevented by spring steel. Spring steel is a steel that, in comparison to other steels higher Has strength. A workpiece made of spring steel can up to a certain through the material Tension (elastic limit) be bent to thereafter without permanent deformation elastic in to return to the initial state. The material property that makes this possible is the elasticity. The substrate does not have to be spring band steel. It can also be FR 4. FR 4 is a name for the fire resistance of the printed circuit board material; FR4 is the common one Standard for Consumer electronics.

According to a preferred embodiment of the present invention, the detector comprises a plurality of sensors mounted on opposite sides of the substrate. The reliability of the collected data is of the utmost importance for biomechanical application. Both sensors detect substantially the same bending of the substrate, which the Diffraction of the object to be examined, for example, the back, understands. Consequently, the diffraction is represented by two measured values of the sensors to be determined at the same time. The actual bend can thus be determined with greater accuracy and reliability.

Of the Bending sensor according to a preferred embodiment includes a detector comprising a plurality of sensors for detecting the Bending parameter has in each case different measuring zones. The sensors can Cascaded or overlapping are arranged. Thus, it is possible from the spatially resolved the body movement to capture the resulting bending information by measurement. each Bend-sensitive measuring zone detects the respective in their measuring section applied curvature in positive or negative bending direction in at least one room level. The in the different measuring zones arranged sensors are preferably offset in time controlled, in particular with a clock frequency of 1 kHz or more, the more the better (pulse operation = energy saving). This will be the The amount of data collected is significantly reduced, because it will become everyone Date only data read from a single sensor. At the same time, the readout frequency is large enough to match the dynamics of the Motion spatially resolved For example, at a drive frequency of 1 kHz and For example, 10 bending zones a readout frequency of 100 Hz possible what dynamic motion detection (speed, acceleration of the Bend) possible power.

Of Furthermore, the bending sensor according to the invention a space position sensor for detecting the position of the sensor relative to the gravitational field of the earth or the earth's magnetic field. The gravitational field of the earth provides a constant direction. The spatially resolved Measurement of the diffraction allows it is the bend in a certain plane relative to the direction of the To capture gravitational field. Thus, for example, determined be like the back is bent to lift loads.

Of the Room position sensor can also be a start vector for the detection of bending information pretend. The room position sensor detects the position of the sensor on the back Beginning of the bending measurement. The following recorded bend represents a relative deviation the orientation of the start vector.

The Data collected by the detector is preferably from the detection device output as digitized electronic signals and in one stored electronic data memory. As data storage can For example, a flash memory such as an SD memory card or micro SD card be used. The flash memory has the advantage of being relatively small and lightweight and stores the stored data, without the data storage being connected to a power supply must be. The flash memory can with the fastener be fastened together on the examination object. However requires the flash memory is a power supply for reading in or out of Dates. Alternatively, the data store can also be in a separate Storage unit be provided. The data transfer is then wired or wirelessly to the external data store. This embodiment allows it is to make the electronics of the bending sensor significantly smaller.

The inventive fastener may in particular comprise a readable identifier memory unit. The tag storage unit contains an electronic identifier for identification of the fastener. It is thus possible to identify the fastener to prevent it improperly against another product is exchanged. This feature is used in particular quality assurance, because the identification allows to ensure that only the measurement provided for bending sensor with the fastener can be used.

When Identification memory unit for identifying the fastening element For example, an RFID transponder for wireless reading be provided the electronic identifier. The English term Radio Frequency Identification (RFID) refers to a system for Identification with the help of electromagnetic waves. An RFID system consists of a transponder located on or in the to be identified Item is located and this features and a reader for reading the transponder identifier. The detector according to the invention can then be equipped with a reader be provided for reading the identifier in the RFID transponder. The reading takes place via an antenna, which already exists as an antenna for the measurement data transfer Data lines are used, these with z. B. 13.2 MHz modulated and thus be made usable as an antenna, what more electrical cables for makes an antenna unnecessary. These measures ensure that neither the detector nor the fastener against another Product can be exchanged. A clear association with the manufacturer and the number of applications is made possible with it. Even a multiple use of the fastener is thus excluded.

The sensor (s) are preferably obtained by lamination, extrusion, casting, Welding or heating a shrink tube is enclosed in a container sealed against environmental influences. This feature is designed to ensure that the sensor is protected from potentially damaging environmental factors such as moisture or dirt. In particular, when the bending sensor according to the invention is used for long-term studies over days or weeks, such protection is necessary.

The detected bending parameters are preferably used to a To determine variety of dynamics parameters. In particular, the bending angle as a function of time and / or location, the bending speed as a function of time and / or location, the bending acceleration as a function of time and / or location, the Fourier transform the functions of the bending angle, the bending speed and / or the bending acceleration can be derived.

The recorded bend data are preferably in a histogram for graphical representation of the frequency distribution the dynamic parameter entered. A histogram is a graphic one Representation of the frequency distribution of readings. It is based on the ordered by size data and divides the entire area of the sample into classes. About everyone Class becomes an area built, whose area is proportional to the class-specific frequency. Especially the bending angle, the bending speed or the bending acceleration are shown in such histograms. A frequency distribution of the spatial position The bending sensor may also be used as a histogram or as a gray scale a coordinate system is displayed. The recorded bending parameters become compared with average bending parameters to determine aberrations in to indicate the motion parameters. Such a comparison is facilitated by the histogram representation.

Preferably At the same time as the bending parameters, further parameters, such as for example, pain parameters, posture parameters, mobility parameters, recorded and a statistical correlation is between the bending parameters and the other parameters. The statistical correlation does not say, however, whether a causal relationship between the different parameters. The recognition of such relationships by however, a scientist or doctor will be relieved if appropriate statistical correlations can be represented.

The Detecting bending parameters of the bending sensor preferably takes place via a Period of at least 24 hours to allow a long-term analysis. The application is therefore analogous to long-term ECG measurements are in any periods possible up to 24 h. The detection of bending parameters can in particular accompany therapy carried out is going to be a positive or negative correlation between therapeutic activities and determine the detected motion parameters.

preferred embodiments The present invention will be described below with reference to FIG the attached Drawings described.

1 shows an example of the application of a bending sensor according to the invention on the back of a person.

2 shows a first embodiment of a detector of a bending sensor according to the invention.

3 shows a Cartesian coordinate system in which the dependence of an electrical resistance change (ΔR) of the detector from a bending angle (Φ) is shown.

4 shows a schematic view of the second embodiment of a bending sensor according to the invention.

5 shows a sectional view of the bending sensor of the second embodiment in a sectional plane 130 ,

6 shows a third embodiment of a bending sensor according to the invention.

7 shows a sectional view of the bending sensor of the third embodiment in a sectional plane 130

1 shows an example of the application of a bending sensor according to the invention on the back of a person. A two-strip bend-sensitive detector 10 is shown, the strips are mounted side by side on the back of the person. Strip-shaped elastic bands are in 1 run parallel to the spine along the back. They are by means of fasteners 20 attached to the back. A data line 40 is provided which the detected bending parameters to an electronic data storage 30 transfers.

In 2 is a side view of the strip-shaped detector section 10 from 1 shown. The detector 10 comprises a strip-shaped substrate 10 , On the opposite sides of the strip-shaped substrate 50 are each strain gauges 60 and 17 arranged. The mutually oppositely arranged stretch marks each define a measurement zone of the Detek tors. The strain gauges 60 and 70 are measuring devices for the detection of distending deformations. They change their impedance even at low deformations and are used as strain sensors. When the in 1 As shown person bends their backs, so are the strain gauges 60 and 70 each stretched. This mechanical deformation changes the electrical resistance of the strain gauges 60 and 70 ,

In 3 the relationship between the mechanical deformation of the strain gauges and the change in electrical resistance in a Cartesian coordinate system is shown. The bending angle Φ is plotted on the abscissa. The bending angle Φ is a simple function of the strain gauge strain. Each individual bending-sensitive measuring zone of a sensor band is calibrated, whereby the calibration curves are stored on the sensor band electronics. The ordinate of the coordinate system represents the change of the electrical resistance .DELTA.R to a resistance of an undeformed strain gauge 85 represents the calibration curve; it indicates the functional relationship between resistance change ΔR and bending angle Φ. The calibration curve 85 in 3 is a simple straight line passing through the origin of the coordinate system. This waveform is shown by way of example only. The calibration curves 85 However, for larger bending angles Φ, they deviate from the straight line shape. The calibration is necessary to allow the most accurate detection of the bending angle. In addition to strain gages, it is also possible to use optical waveguides with surface structuring in the region of the bending-sensitive measuring zones. In addition to the ohmic resistance, it is also possible to use changes in the electrical capacitance or inductance as a measure of the bending angle. In general, the complex AC resistance Z or the impedance against the bending angle to be detected can be recorded as a calibration curve.

In 3 is shown a further embodiment of the bending sensor according to the invention. The bending sensor comprises a unit for the detector electronics 120 connected to a bending-sensitive detector 10 connected. The bending-sensitive detector comprises a strip-shaped substrate 50 , Along the strip-shaped substrate 50 is a variety of strip strain gauges 110 arranged. The longitudinal axis of the strain gauges 110 is in each case parallel to the longitudinal axis of the strip-shaped substrate 50 aligned. Neighboring stretch marks 110 are each partially placed side by side on the strip-shaped substrate, so that an initial portion of a first stretch strip 110 each adjacent to an end portion of a subsequent stretch strip 110 lies. reference numeral 130 represents a sectional plane through the bending-sensitive detector, where the beginning and end portion of two adjacent stretch marks are arranged side by side on the strip-shaped substrate.

In 5 is a cross section of the bending-sensitive detector 10 out 4 in the cutting plane 130 shown. This in 5 illustrated substrate 50 is preferably made of spring steel. This material has sufficient strength and flexibility to the strain gauges 110 take. In 5 is shown that the strain gages 110 by means of an adhesive layer 40 on the substrate 50 are attached. As an adhesive layer 40 For example, an epoxy resin can be used which at the same time provides effective electrical isolation of the strain gauge from the substrate. substratum 50 and strain gauges are from a protective cover 100 locked in. As a protective sheath is preferably a shrink tube used.

In 6 another embodiment of the present invention is shown. reference numeral 120 in 6 indicates the detector electronics of the illustrated bending sensor; this is preferably via a data line with an external in 6 not shown data storage connected. Thus, the size and weight of the bending sensor can be reduced overall. Of course, it is also possible to forward the acquired motion parameters via a wireless connection, for example Bluetooth (IEEE 802.15.1), WLAN (IEEE 802.11) or UMTS. The evaluation and storage of the acquired motion parameters can thus be transmitted to external computers. In particular, it is possible to evaluate the acquired data in real time, in turn, to give the wearer of the bending sensor information for reducing or preventing back pain.

The in 6 The illustrated bending sensor further comprises a substrate 50 on the strain gauge 110 are arranged in cascading. The term cascading here alone refers to the spatial arrangement of the strain gauges. The strain gauges 110 are not connected in series, but connected in parallel. Thus, each strain gauge can be individually controlled and read. Each strain gauge 50 is intended to detect motion parameters at different locations or measurement zones, so that a spatially resolved representation of motion parameters can be obtained. The strain gauges 110 are each successively along a longitudinal axis of the substrate 50 arranged. In 6 is merely a plan view represented the bending sensor. On the rear side of the bending sensor, not shown, in turn strain gauges are arranged in the same manner as on the illustrated front side.

In 7 is a cross section of the bending sensor of 6 along a cutting plane 130 shown. On the opposite sides of the substrate 50 are each strain gauges 110 arranged. By means of an adhesive layer 140 are the strain gauges 110 each on the substrate 50 attached. By combining two parallel (sandwich structure) arranged, inversely or rectilinearly oriented sensors per bending-sensitive measurement zone, the measurement accuracy, the measurement range, the susceptibility to interference and thus the reproducibility of the bending signals is increased since thermal, mechanical and electromagnetic influences as well as degradation of the sensors are compensated.

10

bending sensitive detector

20

fastener

30

data storage

40

data line

50

substratum

60

upper Strain gauges

70

lower Strain gauges

80

measuring zones

85

calibration curve

90

power supply

100

cover

110

Strain gauges

120

detector electronics

130

cutting plane

140

adhesive for strain gages

Claims (30)

Bending sensor for detecting functional parameters for characterizing movements on the human or animal body, with a fastening element ( 20 ), in particular a fixing plaster, for fixing the bending sensor on the skin of the human or animal body, a bending-sensitive detector ( 10 ) for detecting bending parameters of the bending sensor, in particular a bending angle, a bending speed and a bending acceleration, and a data memory ( 30 ) for storing the detected bending parameters, characterized in that the fastening element is stretchable and has a stretchable cavity for receiving a sensor of the detector, wherein the sensor is fixed to a reference point of the fastening element in the cavity. Bending sensor according to one of claims 1, wherein the fastening element ( 20 ) has an elastic lower layer with biocompatible thermally activatable adhesive layer for application to the skin and an elastic upper layer, wherein the cavity between the upper layer and lower layer is formed. Bending sensor according to claim 1 or 2, wherein the sensor has a light guide with a transfer function which varies depending on a bending of the light guide changed. Bending sensor according to claim 3, wherein the sensor has a strain gauge with a has electrical impedance, which is with an elongation or Upset of the strain gauge changed. Bending sensor according to one of claims 1 to 4, the detector comprises a detection device, wherein the detection device, a change of the electrical impedance of the strain gauge ( 60 . 70 ) or a change in the transfer function of the light guide detected. Bending sensor according to claim 5, wherein the detection device is adapted to the change of the electrical impedance of a strain gauge ( 60 . 70 ) or to detect the change in the transfer function of the optical fiber at a predetermined sampling frequency of, for example, 100 Hz. Bending sensor according to claim 5 or 6, with an electronic data memory for storing the digitized electronic output from the detection device Signals. Bending sensor according to a the claims 1 to 7, wherein the detector is a tensile and elastically bendable Substrate has, on which the sensor is mounted. Bending sensor according to claim 8, wherein the substrate is made of spring steel. Bending sensor according to claim 8 or 9, wherein the detector has a plurality of sensors, the are mounted on opposite sides of the substrate. Bending sensor according to one of the preceding claims 1 to 10, wherein the detector ( 10 ) several sensors for detecting the bending parameters in different measuring zones ( 80 ) having. Bending sensor according to claim 11, wherein the sensors are cascaded or overlapping are orders. Bending sensor according to one of claims 1 to 12, wherein the detection device is adapted to the in the different measuring zones ( 80 ) arranged time offset to control, in particular with a drive frequency of at least 1 kHz. Bending sensor according to a the claims 1 to 13, with a space position sensor for detecting the position of Sensor relative to the gravitational field of the earth or to the earth's magnetic field. Bending sensor according to one of claims 6 to 14, wherein the fastening element ( 20 ) has a layer of spring steel for mechanical stabilization and electromagnetic shielding. Bending sensor according to one of claims 1 to 15, wherein the fastening element ( 20 ) has a readable identifier memory unit, wherein in the identifier memory unit, an electronic identifier for identifying the fastener is stored. Bending sensor according to claim 16, wherein the tag storage unit includes a RFID transponder for wireless identification Reading the electronic identifier has. Bending sensor according to claim 16 or 17, wherein the detector is a reader for reading the identifier having. Bending sensor according to a the preceding claims, wherein the RFID transponder as an antenna already for the measurement data transfer existing data line used. Method for acquiring functional parameters for Characterization of movements on human or animal Body, with the steps: Attaching a bending sensor to the human or animal body, To capture bending parameters of the bending sensor, in particular a bending angle, a bending speed and a bending acceleration, Determine the body movement based on the recorded bending parameters, characterized by the steps to provide a stretchable fastener for Attaching the bending sensor, wherein the fastener a expandable cavity for receiving a sensor of the detector has, and fix the sensor at a reference point of the fastener in the cavity. Method according to claim 20, with the step detecting a position of the bending sensor means a spatial position sensor, wherein the position relative to the gravitational field Earth or geomagnetic field is detected. A method according to claim 20 or 21, wherein the bending parameters are detected spatially resolved by a plurality of bending-sensitive measuring zones ( 80 ) of the bending sensor are used for detecting bending parameters. Method according to claim 20, 21 or 22, wherein the bending parameters detected time-resolved be by the bending parameters at a predetermined sampling frequency be detected by, for example, 100 Hz. Method according to one the preceding claims, wherein the detected bending parameters are used to generate a plurality of dynamic parameters, in particular the bending angle as a function of time and / or location, the bending speed as a function of time and / or location, the bending acceleration as a function of time and / or location, the Fourier transform of Functions of the bending angle, the bending speed and / or the Bending acceleration. Method according to claim 24, wherein a histogram for the graphical representation of the frequency distribution the dynamics parameter, in particular the bending angle, bending speed or bending acceleration is used. Method according to claim 24 or 25, where a frequency distribution the spatial position of the bending sensor as a histogram or as gray value in a coordinate system is displayed. Method according to one of the preceding claims 20 to 26, wherein the detected bending parameters with average bending parameters can be compared to indicate aberrations in the motion parameters close. Method according to one of the preceding claims 20 to 27, wherein at the same time as the bending parameters, further parameters, such as pain parameters, posture parameters, mobility parameters, and a statistical correlation between the bending parameters and the other parameter is produced. Method according to one the claims 20 to 28, wherein the detection of bending parameters of the bending sensor over a Period of at least 24 hours takes place to a long-term analysis to enable. Method according to one of the preceding claims 20 to 29, wherein the detection of bending parameters therapy accompanying carried out is going to be a positive or negative correlation between therapeutic activities and determine the detected motion parameters.