WO2020026880A1

WO2020026880A1 - Active electrode, electroencephalograph, control device, and control method

Info

Publication number: WO2020026880A1
Application number: PCT/JP2019/028742
Authority: WO
Inventors: 秋憲松本
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2018-08-02
Filing date: 2019-07-23
Publication date: 2020-02-06
Also published as: JPWO2020026880A1

Abstract

This active electrode is provided with: a measurement electrode (51a) that is brought into contact with a living body; a first amplification circuit (52a) to which a first biological signal detected by the measurement electrode (51a) is inputted; a first current source (53a) for causing a first current for measuring contact impedance between the measurement electrode (51a) and the living body, to flow to the living body via the measurement electrode (51a); and a second current source (54a) for causing a second current for applying electric stimulation to the living body, to flow to the living body via the measurement electrode (51a).

Description

Active electrode, electroencephalograph, control device, and control method

The present invention relates to an active electrode, an electroencephalograph, a control device, a control method, and the like.

生体 A biological signal measuring device that measures a subject's brain wave or heart rate as a biological signal is known. As an example of such a biological signal measurement device, Patent Literature 1 discloses a device in which lead-off detection is accurately performed and power consumption of the system is minimized.

Japanese Patent Publication No. 2007-508095

The present invention provides an active electrode, an electroencephalograph, a control device, a control method, and a program that can apply electrical stimulation to a living body via an electrode for detecting a biological signal.

The active electrode according to one embodiment of the present invention is a first electrode that comes into contact with a living body, a first amplifier circuit to which a first biological signal detected by the first electrode is input, and a second amplifier for measuring contact impedance. A first current source for flowing one current to the living body through the first electrode, and a second current for flowing a second current to the living body through the first electrode for applying electrical stimulation to the living body. And a current source.

脳 The electroencephalograph according to one aspect of the present invention includes the active electrode, and a mounting portion mounted on the living body and provided with the first electrode.

A control device according to one embodiment of the present invention is a control device that controls an active electrode, wherein the active electrode is configured to receive a first electrode that comes into contact with a living body and a first biological signal detected by the first electrode. A first amplifier circuit, a first current source for flowing a first current for measuring contact impedance to the living body through the first electrode, and a second current for applying electrical stimulation to the living body A second current source for flowing into the living body through the first electrode, the control device selectively electrically connects the first current source and the second current source to the first electrode. A control unit for connection is provided.

A control method according to an aspect of the present invention is a control method of an active electrode, wherein the active electrode is configured to receive a first electrode that contacts a living body and a first biological signal detected by the first electrode. A first amplifier circuit, a first current source for flowing a first current for measuring contact impedance to the living body through the first electrode, and a second current for applying electrical stimulation to the living body. A second current source for flowing into the living body via a first electrode, wherein the control method selectively connects the first current source and the second current source to the first electrode. .

A program according to one embodiment of the present invention is a program for causing a computer to execute the control method.

The active electrode, the electroencephalograph, the control device, the control method, and the program of the present invention can apply electric stimulation to a living body through an electrode for detecting a biological signal.

FIG. 1 is an external view illustrating a configuration of a biological signal measurement system according to an embodiment. FIG. 2A is a diagram illustrating an example of a shape and a schematic configuration of an ear-hung type electroencephalograph. FIG. 2B is a diagram illustrating an example of a shape and a schematic configuration of a neck-mounted electroencephalograph. FIG. 2C is a diagram illustrating an example of a shape and a schematic configuration of an eyeglass-type electroencephalograph. FIG. 3A is a diagram illustrating a first example of the shape of the contact surface of the electrode that contacts the skin of the subject. FIG. 3B is a diagram illustrating a second example of the shape of the contact surface of the electrode that contacts the skin of the subject. FIG. 3C is a diagram illustrating a third example of the shape of the contact surface of the electrode that contacts the skin of the subject. FIG. 3D is a diagram illustrating a fourth example of the shape of the contact surface of the electrode that contacts the skin of the subject. FIG. 3E is a diagram illustrating a fifth example of the shape of the contact surface of the electrode that contacts the skin of the subject. FIG. 4 is a block diagram illustrating an overall configuration of the biological signal measurement system according to the embodiment. FIG. 5 is a functional block diagram illustrating a detailed configuration of the electroencephalograph and the information processing device. FIG. 6 is a block diagram illustrating a hardware configuration of the electroencephalograph. FIG. 7 is a block diagram illustrating a hardware configuration of the information processing apparatus. FIG. 8 is a flowchart illustrating a flow of a basic process of the biological signal measurement system according to the embodiment. FIG. 9 is a circuit block diagram illustrating a detailed configuration of the biological signal measurement device according to the embodiment in a contact impedance measurement mode. FIG. 10 is a circuit block diagram showing a detailed configuration of the biological signal measurement device according to the embodiment in an electric stimulation mode using a measurement electrode. FIG. 11 is a circuit block diagram illustrating a detailed configuration of a biological signal measurement device according to a modification. FIG. 12 is a diagram illustrating a detailed configuration of the second current source configured by the current output type DA converter. FIG. 13 is a truth table used to control the second current source constituted by the current output type DA converter. FIG. 14 is a diagram showing a detailed configuration of a fourth current source constituted by a current output type DA converter. FIG. 15 is a truth table used to control the fourth current source constituted by the current output type DA converter. FIG. 16 is a diagram showing the relationship between the operation mode and the state of the switching element. FIG. 17 is a diagram showing a current waveform for measuring contact impedance and a current waveform for electrical stimulation. FIG. 18 is a diagram illustrating an example of switching operation modes. FIG. 19 is a diagram illustrating an example of a component arrangement in the first active electrode. FIG. 20 is a flowchart of a display operation example of the biological signal measurement system according to the embodiment. FIG. 21 is a diagram illustrating a display example on the presentation unit when brain wave measurement is performed in the contact impedance measurement mode. FIG. 22 is a diagram illustrating a display example on the presentation unit when brain wave measurement is performed in the electric stimulation mode. FIG. 23 is a diagram illustrating a display example on the presentation unit when brain wave measurement is not performed in the electric stimulation mode. FIG. 24 is a diagram illustrating an operation example including the motion measurement mode of the biological signal measurement system according to the embodiment. FIG. 25 is a diagram illustrating an improvement in a walking motion of a subject by electrical stimulation.

Hereinafter, embodiments will be specifically described with reference to the drawings. Each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and do not limit the present invention. Further, among the components in the following embodiments, components not described in the independent claims are described as arbitrary components.

図 In addition, each figure is a schematic diagram, and is not necessarily strictly illustrated. In each of the drawings, substantially the same components are denoted by the same reference numerals, and redundant description may be omitted or simplified.

(Embodiment)
[Overview of biosignal measurement system]
FIG. 1 is an external view illustrating a configuration of a biological signal measurement system 100 according to an embodiment. FIG. 1 also shows a subject 5 to be measured.

The biological signal measurement system 100 is a system that measures a biological signal of the subject 5 and includes an electroencephalograph 10, an information processing device 20, and a presentation unit 30. The electroencephalograph 10, the information processing device 20, and the presentation unit 30 are connected by wired communication or wireless communication, respectively, and transmit and receive information between the devices.

The electroencephalograph 10 is an example of a device that detects a biological signal, and is attached to the ear of the subject 5 (more specifically, the periphery of the ear). The plurality of electrodes 51 (see FIG. 2A) include a measurement electrode that measures a biological signal and a reference electrode that measures a reference potential used to calculate a difference between a potential measured by the measurement electrode. The plurality of electrodes 51 also include a ground electrode. The ground electrode does not refer to a general ground electrode (electrode having a ground potential), but refers to an electrode having a potential serving as a reference potential in the subject 5.

(4) The information processing device 20 receives an operation input from the electroencephalograph 10, and performs a predetermined process. For example, the information processing device 20 is a computer. The “predetermined process” here is a general term for applications such as games, health management, learning, etc., which are implemented on a home computer.

The presentation unit 30 is an output device that presents the results of the processing performed by the information processing device 20. Here, “present” includes both displaying an image on a display and / or outputting sound from a speaker. That is, the presentation unit 30 is a display and / or a speaker that displays image information or outputs acoustic information.

[Structure of electroencephalograph]
2A to 2C are diagrams illustrating an example of a shape and a schematic configuration of the electroencephalograph 10. FIG. 2A shows the ear-mounted electroencephalograph 10, FIG. 2B shows the neck-mounted electroencephalograph 10, and FIG. 2C shows the eyeglass-type electroencephalograph. The subject 5 wears the electroencephalograph 10 shown in FIGS. 2A to 2C on the ear.

As shown in FIG. 2A, the electroencephalograph 10 is an ear-hung type electroencephalograph and has an arch shape along the ear of the subject 5. The electroencephalograph 10 includes a plurality of electrodes 51 and the mounting unit 40.

The mounting unit 40 is an arch-shaped member provided with a plurality of electrodes 51, which is mounted on the ear of the subject 5. The mounting unit 40 includes an operation surface 43, and the operation surface 43 is provided with operation buttons 41 and a display unit 47. The plurality of electrodes 51 are provided on a surface of the mounting unit 40 facing the subject.

Before mounting the electroencephalograph 10, the subject 5 operates the operation button 41 arranged on the operation surface 43 to activate the electroencephalograph 10, and then mounts the electroencephalograph 10 on the ear. The display unit 47 arranged on the operation surface 43 displays the status of the operation, the processing result of the application, and the like.

In the electroencephalograph 10, for example, an electrode located above the ear of the subject 5 (that is, near the brain of the subject 5) among the plurality of electrodes 51 is used as a measurement electrode described later. An electrode located behind the ear of the subject 5 (for example, near a mastoid) is used as a reference electrode described later. Further, an electrode in contact with the vicinity of the earlobe among the plurality of electrodes 51 is used as a ground electrode. Note that such an arrangement of the electrodes is an example, and the arrangement of the electrodes is not particularly limited. For example, of the plurality of electrodes 51, an electrode located beside the ear of the subject 5 is used as a measurement electrode, an electrode located near the mastoid or earlobe is used as a reference electrode, and an electrode located near the earlobe is grounded. It may be used as an electrode.

As shown in FIG. 2B, two ear-mounted electroencephalographs 10 may be connected and used as a neck-mounted electroencephalograph. As shown in FIG. 2C, two ear-hung type electroencephalographs 10 may be connected to be used as a glasses-type electroencephalograph. In the eyeglass-type electroencephalograph, the electrode 51 may be provided on the arm (on the temple).

[Electrode shape]
3A to 3E are diagrams illustrating examples of the shape of the contact surface of the electrode 51 that contacts the skin of the subject 5. FIG. The material of the electrode 51 is made of a conductive substance. An example of the material of the electrode 51 is gold or silver. A desirable material for the electrode 51 is silver-silver chloride (Ag / AgCl). This is because silver-silver chloride has a small polarization when it comes into contact with a living body and has a stable polarization voltage.

The shape of the contact surface of the electrode 51 may be a circle (for example, a diameter of 10 mm) shown in FIG. 3A similar to an electrode used for medical use, or may be various shapes depending on the application. For example, it may be a triangle as shown in FIG. 3B, a square or a square as shown in FIG. 3C, a pentagon as shown in FIG. 3D, or a hexagon as shown in FIG. 3E.

[Configuration of biological signal measurement system]
FIG. 4 is a block diagram showing the overall configuration of the biological signal measurement system 100. As described above, the biological signal measurement system 100 includes the electroencephalograph 10, the information processing device 20, and the presentation unit 30. The electroencephalograph 10 includes an operation input device 10a and a biological signal measurement device 10b.

The electroencephalograph 10 receives the operation input of the subject 5 at the operation input device 10a, and measures the biological signal of the subject 5 at the time of the operation at the biological signal measuring device 10b. The biological signal measured by the electroencephalograph 10 is transmitted to the information processing device 20.

The information processing device 20 receives an input from the operation input device 10a or the biological signal measuring device 10b, performs a predetermined process, and outputs a processing result to the presentation unit 30. The electroencephalograph 10 and the information processing device 20 are connected by wireless communication or wired communication.

FIG. 5 is a functional block diagram showing a detailed configuration of the electroencephalograph 10 and the information processing device 20. Here, an example in which the electroencephalograph 10 and the information processing device 20 are connected by wireless communication will be described.

First, the operation input device 10a will be described. The operation input device 10a includes an operation input unit 11 and an operation signal output unit 12.

The operation input unit 11 is an input device that acquires operation input information input from the operation buttons 41 (see FIGS. 2A and 2B) and determines the content of the operation. The operation signal output unit 12 is a transmitter that transmits the operation input information acquired by the operation input unit 11 to the information processing device 20. The operation input information acquired by the operation input unit 11 is transmitted from the operation signal output unit 12 to the information processing device 20.

Next, the biological signal measuring device 10b will be described. The biological signal measuring device 10b includes an electrode unit 13, a biological signal amplifying unit 14, and a biological signal output unit 15.

The electrode section 13 is composed of a plurality of electrodes 51. As described above, the plurality of electrodes 51 include the measurement electrode, the reference electrode, and the ground electrode. The plurality of electrodes 51 are arranged, for example, at positions that come into contact with the skin of the subject 5.

The biological signal amplifying unit 14 is an amplifier that amplifies a biological signal corresponding to a potential difference between the plurality of electrodes 51. Specifically, the biological signal amplification unit 14 measures a potential difference between the measurement electrode and the reference electrode, and amplifies the measured potential difference. The amplified potential difference is converted into a digital signal by an A / D converter (not shown) provided in the biological signal amplifier 14, for example. Note that the biological signal amplifying unit 14 does not need to amplify the biological signal when it can measure a biological signal having a potential of a predetermined value or more, and may simply measure the potentials of the plurality of electrodes 51.

The biological signal output unit 15 is a transmitter that transmits the potential difference amplified by the biological signal amplifier 14 to the information processing device 20. The potential difference of the biological signal converted into a digital value by the biological signal amplifier 14 is transmitted from the biological signal output unit 15 to the information processing device 20.

Next, the information processing device 20 will be described. The information processing device 20 includes an operation signal acquisition unit 21, a biological signal acquisition unit 22, a biological signal processing unit 23, an application processing unit (application processing unit) 26, a display information output unit 27, and an acoustic information output unit 28.

The information processing device 20 receives information from the electroencephalograph 10 by receiving operation input information at the operation signal acquisition unit 21 and receiving a biological signal at the biological signal acquisition unit 22.

In many cases, a biosignal cannot be used as information with an original signal that has just been recorded. Therefore, the biological signal processing unit 23 performs a process of extracting meaningful information from the original signal. For example, in the case of brain wave measurement, the biological signal processing unit 23 extracts a signal of a specific frequency (for example, 10 Hz) and calculates a power spectral density (Power \ Spectral \ Density) of the signal at the frequency. Note that the biological signal processing unit 23 may be arranged on the electroencephalograph 10 side instead of the information processing device 20. That is, in the present embodiment, an electronic device may be configured by the electroencephalograph 10 and the biological signal processing unit 23.

(4) The application processing unit 26 performs central application processing (application processing) of the information processing apparatus 20. The application process is realized by receiving a signal from the electroencephalograph 10 and performing a predetermined process. The predetermined processing is, for example, game progress in a game application, recording / data management / display in a health management application, question / score / result display in a learning application, and the like.

(4) The result processed by the application processing unit 26 is output from the application processing unit 26 to the display information output unit 27 and the audio information output unit 28. The display information output unit 27 and the audio information output unit 28 output a visual or auditory signal to the presentation unit 30 in order to feed back the result processed by the application processing unit 26 to the subject 5.

The presentation unit 30 presents (ie, displays and / or outputs audio) the signals output from the display information output unit 27 and the audio information output unit 28. Thereby, a signal is presented to the subject 5. The presentation unit 30 is, for example, a television, a display, or a speaker.

[Hardware configuration of electroencephalograph]
FIG. 6 is a block diagram illustrating a hardware configuration of the electroencephalograph 10. The electroencephalograph 10 includes an operation button group 71, a control signal conversion circuit 72, a measurement electrode 51a, a reference electrode 51b, a ground electrode 51c, a differential amplifier circuit 74, an A / D converter 75, a transmission circuit 79, a signal processing unit 78, and an antenna. 80 and a battery 81.

The operation button group 71 and the control signal conversion circuit 72 correspond to the operation input unit 11 shown in FIG. Each button in the operation button group 71 corresponds to the operation button 41. The measurement electrode 51a, the reference electrode 51b, and the ground electrode 51c correspond to the electrode 51 illustrated in FIGS. 2A and 2B and the electrode unit 13 illustrated in FIG. The differential amplifier circuit 74 and the A / D converter 75 are included in the biological signal amplifier 14.

The signal processing unit 78 has a CPU 101, a RAM 102, a program 103, and a ROM 104. Further, the transmission circuit 79 and the antenna 80 function as the biological signal output unit 15 and / or the operation signal output unit 12 illustrated in FIG. The transmitting circuit 79 and the antenna 80 may be referred to as an “output unit” or a “transmitter”.

These components are connected to each other by the bus 105, and can exchange data with each other. The electroencephalograph 10 operates using the battery 81 as a power supply.

押下 Pressing information of each button related to the operation button group 71 is converted into a control signal for controlling the operation of the electroencephalograph 10 in the control signal conversion circuit 72 and sent to the CPU 101 via the bus 105.

(4) The measurement electrode 51a, the reference electrode 51b, and the ground electrode 51c are directly connected to the differential amplifier circuit 74, or are connected via a buffer amplifier or the like. These electrodes are installed at predetermined locations on the electroencephalograph 10. The potential difference between the measurement electrode 51a and the reference electrode 51b is amplified by the differential amplifier circuit 74, and is converted by the A / D converter 75 from an analog biological signal to a digital biological signal. The potential difference converted into a digital biological signal is sent to the CPU 101 via the bus 105 as a biological signal that can be processed and transmitted.

The CPU 101 executes the program 103 stored in the RAM 102. The program 103 describes a signal processing procedure in the electroencephalograph 10 shown in a flowchart of FIG. 8 described later. The electroencephalograph 10 converts the operation signal and the biological signal into digital signals according to the program 103 and transmits the digital signals from the antenna 80 via the transmission circuit 79. The program 103 may be stored in the ROM 104 in some cases.

Note that the signal processing unit 78, the control signal conversion circuit 72, the transmission circuit 79, the differential amplifier circuit 74, and the A / D converter 75 include a DSP (Digital Signal Processor) in which a computer program is incorporated in one semiconductor integrated circuit. It may be realized as hardware. When mounted on one semiconductor integrated circuit, the mounting area can be reduced and the power consumption can be reduced.

Further, the differential amplifier circuit 74 and the A / D converter 75 are integrated in one semiconductor integrated circuit, and the signal processing unit 78, the control signal conversion circuit 72, and the transmission circuit 79 are integrated in another semiconductor integrated circuit. One semiconductor integrated circuit may be connected in one package, integrated as a SiP (System in Package), and realized as hardware such as a DSP incorporating a computer program. By realizing the two semiconductor integrated circuits in separate manufacturing processes, an effect of reducing costs as compared with a case where the two semiconductor integrated circuits are mounted on one semiconductor integrated circuit can be obtained.

[Hardware configuration of information processing device]
FIG. 7 is a block diagram illustrating a hardware configuration of the information processing apparatus 20. The information processing device 20 includes an antenna 83, a receiving circuit 82, a signal processing unit 108, an image control circuit 84, a display information output circuit 85, an audio control circuit 86, an audio information output circuit 87, and a power supply 88. Among these components, the antenna 83 and the receiving circuit 82 correspond to the biological signal acquisition unit 22 and / or the operation signal acquisition unit 21 illustrated in FIG. These are sometimes called "receivers".

The signal processing unit 108 includes a CPU 111, a RAM 112, a program 113, and a ROM 114. The signal processing unit 108 corresponds to the biological signal processing unit 23 and / or the application processing unit 26 illustrated in FIG. The image control circuit 84 and the display information output circuit 85 correspond to the display information output unit 27 shown in FIG. The sound control circuit 86 and the sound information output circuit 87 correspond to the sound information output unit 28 shown in FIG. These are connected to each other via a bus 115, and can exchange data with each other. Power is supplied from a power supply 88 to each circuit.

操作 The operation information and the biological information from the electroencephalograph 10 are received by the receiving circuit 82 via the antenna 83, and sent to the CPU 111 via the bus 115.

(4) The CPU 111 executes the program 113 stored in the RAM 112. The program 113 describes a signal processing procedure in the information processing device 20 shown in a flowchart of FIG. 8 described later. The information processing device 20 converts an operation signal and a biological signal in accordance with the program 113, performs a process for executing a predetermined application, and generates a signal for performing feedback to the subject 5 by image or sound. The program 113 may be stored in the ROM 114 in some cases.

The image feedback signal generated by the signal processing unit 108 is output from the display information output circuit 85 to the presentation unit 30 via the image control circuit 84. Similarly, the audio feedback signal generated by the signal processing unit 108 is output from the audio information output circuit 87 via the audio control circuit 86.

The signal processing unit 108, the receiving circuit 82, the image control circuit 84, and the sound control circuit 86 may be realized as hardware such as a DSP in which a program is incorporated in one semiconductor integrated circuit. With one semiconductor integrated circuit, the effect of reducing power consumption can be obtained.

[Operation of biological signal measurement system]
Next, the operation of the biological signal measurement system 100 according to the present embodiment configured as described above will be described.

FIG. 8 is a flowchart showing a flow of basic processing of the biological signal measurement system 100. Steps S11 to S14 show processing in the electroencephalograph 10 (step S10), and steps S21 to S25 show processing in the information processing device 20 (step S20).

First, the processing step S10 in the electroencephalograph 10 will be described.

<Step S11>
The operation input unit 11 receives an operation input performed by the subject 5. Specifically, it detects which operation button 41 is being pressed at the reception timing. An example of the reception timing is when the operation button 41 is pressed. The detection of whether or not the operation button 41 is pressed is performed, for example, by detecting a change in a mechanical button position or a change in an electric signal when the operation button 41 is pressed. The operation input unit 11 detects the type of the operation input received by the operation input unit 11 based on the type of the pressed operation button 41 and transmits the operation input to the operation signal output unit 12.

<Step S12>
The operation signal output unit 12 transmits an operation signal corresponding to the operation input received by the operation input unit 11 to the information processing device 20.

<Step S13>
The biological signal amplifier 14 measures and amplifies a biological signal corresponding to a potential difference between the plurality of electrodes 51 in the electrode unit 13. For example, a potential difference between the measurement electrode 51a and the reference electrode 51b among the plurality of electrodes 51 in the electrode unit 13 is measured as a biological signal. Further, the biological signal amplifying unit 14 amplifies the measured biological signal. The amplified biological signal is transmitted from the biological signal amplifier 14 to the biological signal output unit 15.

<Step S14>
Further, the biological signal output unit 15 transmits the transmitted biological signal to the information processing device 20.

In the processing step S10 in the electroencephalograph 10, steps S11 and S12 and steps S13 and S14 may be performed as parallel processing, respectively, and the processing from step S11 to step S14 may be performed in the order described above. There is no need to do this.

Next, the processing step S20 in the information processing device 20 will be described.

<Step S21>
In the information processing device 20, the operation signal acquisition unit 21 receives an operation signal from the operation signal output unit 12. The operation signal acquisition unit 21 transmits the received operation signal to the application processing unit 26.

<Step S22>
The biological signal acquisition unit 22 receives a biological signal from the biological signal output unit 15. The biological signal acquisition unit 22 transmits the received biological signal to the biological signal processing unit 23.

<Step S23>
The biological signal received by the biological signal acquisition unit 22 is analyzed and processed by the biological signal processing unit 23 to extract meaningful information. For example, a biological signal of a predetermined frequency component is extracted. The predetermined frequency component is, for example, 10 Hz in the case of measuring brain waves.

<Step S24>
The application processing unit 26 receives an operation signal from the operation signal acquisition unit 21 and a biological signal from the biological signal processing unit 23, and performs a predetermined process for executing the current application. As described above, the predetermined processing is, for example, game progress in a game application, recording / data management / display in a health management application, question setting / scoring / result display in a learning application, and the like.

<Step S25>
In order to feed back the processing result of the application processing unit 26 to the subject 5, the display information output unit 27 outputs the video information to the presentation unit 30, and the audio information output unit 28 outputs the audio information to the presentation unit 30. As a result, the presentation unit 30 outputs an image and a sound corresponding to the processing result.

In the processing step S20 in the information processing device 20, the processing of step S22, step S23, and step S24 may be performed as parallel processing, respectively. In addition, the application processing unit 26 does not need to perform processing using both the operation signal from the operation signal acquisition unit 21 and the biological signal from the biological signal processing unit 23, and performs processing using only the biological signal. You may. In that case, step S21 of receiving the operation signal can be omitted.

According to the above processing flow, the biological signal measurement system 100 can obtain biological information such as brain waves or electrocardiograms from the subject 5.

[Detailed configuration of biological signal measurement device]
Next, a detailed configuration of the biological signal measuring device 10b included in the electroencephalograph 10 will be described. FIG. 9 is a circuit block diagram illustrating a detailed configuration of the biological signal measurement device 10b included in the electroencephalograph 10. FIG. 9 illustrates a hardware configuration related to the biological signal measurement device 10b among hardware configurations included in the electroencephalograph 10. In FIG. 9, the surface of the body of the subject 5 that is in contact with the measurement electrode 51a and the reference electrode 51b is schematically illustrated by a dashed line.

The biological signal measuring device 10b mainly includes the first active electrode 60a, the second active electrode 60b, the control device 55, the biological signal amplifier 14, and the biological signal output unit 15. The first active electrode 60a includes a measurement electrode 51a, a first amplifier circuit 52a, a first current source 53a, a second current source 54a, a first switching element S1, and a second switching element S2. The second active electrode 60b includes a reference electrode 51b, a second amplifier circuit 52b, a third current source 53b, a fourth current source 54b, a third switching element S3, a fourth switching element S4, and an acceleration sensor 56. . Note that the biological signal measurement device 10b may be regarded as one active electrode. The active electrode means a measurement device in a broad sense including an electrode for measurement and a peripheral circuit for measurement.

The first amplifier circuit 52a is an amplifier to which a biological signal detected by the measurement electrode 51a that comes into contact with the subject 5 (that is, a living body) is input. The measurement electrode 51a is an example of a first electrode, and is electrically connected to an input terminal of the first amplification circuit 52a. The first amplifier circuit 52a functions as a so-called buffer amplifier and performs impedance conversion. In this specification, the term “amplifier circuit” or “amplifier” is not necessarily limited to an amplifier having a voltage amplification factor larger than 1, but also includes an amplifier circuit or an amplifier having a voltage amplification factor of 1 or less. .

The second amplifier circuit 52b is an amplifier to which a biological signal detected by the reference electrode 51b that comes into contact with the subject 5 (that is, a living body) is input. The reference electrode 51b is an example of a second electrode, and is electrically connected to an input terminal of the second amplifier circuit 52b. The second amplifier circuit 52b functions as a so-called buffer amplifier and performs impedance conversion. The second amplifier circuit 52b does not perform voltage amplification (the voltage amplification factor is 1), but may perform voltage amplification.

The biological signal amplifier 14 amplifies the potential difference between the output signal of the first amplifier circuit 52a and the output signal of the second amplifier circuit 52b (that is, the potential difference between the measurement electrode 51a and the reference electrode 51b) and converts the signal into a digital signal. I do. A differential amplifier circuit 74 is used for amplification, and an A / D converter 75 is used for conversion into a digital signal.

The biological signal output unit 15 is a transmitter that transmits the potential difference amplified by the biological signal amplifier 14 to the information processing device 20. The potential difference of the biological signal converted into a digital value by the A / D converter 75 of the biological signal amplifier 14 is transmitted from the biological signal output unit 15 to the information processing device 20.

According to the components described above, the biological signal measurement device 10b can measure a biological signal. In addition, the biological signal measurement device 10b can measure the contact impedance between the electrode and the living body or apply the electrical stimulus to the subject 5 in parallel with the measurement of the biological signal. Hereinafter, components used for measuring contact impedance or applying electrical stimulation to the subject 5 (for example, electrical stimulation to a vestibular organ in the inner ear of the subject 5) will be described.

The first current source 53a is a current source for flowing a first current for measuring the contact impedance Rc1 to the subject 5 via the measurement electrode 51a. The electrical connection between the first current source 53a, the measurement electrode 51a, and the input terminal of the first amplifier circuit 52a is turned on and off by the first switching element S1. The first switching element S1 is, for example, a field effect transistor (FET: Field {Effect} Transistor), but may be another switching element such as a bipolar transistor.

The second current source 54a is a current source for flowing a second current for applying electrical stimulation to the subject 5 to the subject 5 via the measurement electrode 51a. The electrical connection between the second current source 54a, the measurement electrode 51a, and the input terminal of the first amplifier circuit 52a is turned on and off by the second switching element S2. The second switching element S2 is, for example, an FET, but may be another switching element such as a bipolar transistor.

The first current source 53a and the second current source 54a may be realized as individual current source circuits, or may be realized as a single current source circuit. That is, a single current source circuit may have the functions of both the first current source 53a and the second current source 54a, and the first current source 53a and the second current source 54a are separate hardware. It is not mandatory.

The third current source 53b is a current source for flowing a third current for measuring the contact impedance Rc2 to the subject 5 via the reference electrode 51b. The electrical connection between the third current source 53b, the reference electrode 51b, and the input terminal of the second amplifier circuit 52b is turned on and off by the third switching element S3. The third switching element S3 is, for example, an FET, but may be another switching element such as a bipolar transistor.

The fourth current source 54b is a current source for flowing a fourth current for applying electrical stimulation to the subject 5 to the subject 5 via the reference electrode 51b. The electrical connection between the fourth current source 54b, the reference electrode 51b, and the input terminal of the second amplifier circuit 52b is turned on and off by the fourth switching element S4. The fourth switching element S4 is, for example, an FET, but may be another switching element such as a bipolar transistor.

The third current source 53b and the fourth current source 54b may be realized as individual current source circuits, or may be realized as a single current source circuit. That is, a single current source circuit may have the functions of both the third current source 53b and the fourth current source 54b, and the third current source 53b and the fourth current source 54b are separate hardware. It is not mandatory.

The control device 55 includes a control unit 551, a RAM 552, and a ROM 554. The control unit 551 switches between the contact impedance measurement mode and the electric stimulation mode by executing the program 553 stored in the RAM 552. Specifically, the control unit 551 selectively electrically connects the first current source 53a and the second current source 54a to the measurement electrode 51a, and selectively connects the third current source 53b and the fourth current source 54b. It is electrically connected to the reference electrode 51b. The control device 55 is realized by, for example, a microcontroller (MCU).

The acceleration sensor 56 is a so-called three-axis acceleration sensor, and is used to measure the movement of the subject 5 in a movement measurement mode described later. The acceleration sensor 56 is provided on the second active electrode 60b so that, for example, three axes extend in the front-back direction, the left-right direction, and the up-down direction of the subject 5. Note that the acceleration sensor 56 may be provided on the first active electrode 60a or may be provided on the control device 55. The acceleration sensor 56 only needs to be provided in the electroencephalograph 10, and the installation position is not particularly limited.

FIG. 9 is a diagram showing a contact impedance measurement mode for measuring the contact impedance Rc1 (shown schematically in FIG. 9). When the first switching element S1 is turned on, the first current source 53a is turned on. It is electrically connected to the measurement electrode 51a and the input terminal of the first amplifier circuit 52a. In the contact impedance measurement mode, the current supplied from the first current source 53a flows from the measurement electrode 51a in contact with the subject 5 through the subject 5 to the ground electrode 51c (not shown in FIG. 9) that also contacts the subject 5. Flowing.

Although not shown, in the contact impedance measurement mode for measuring the contact impedance Rc2 (schematically shown in FIG. 9), the third current source 53b is turned on by turning on the third switching element S3. 51b and the input terminal of the second amplifier circuit 52b.

接触 The measurement of such contact impedance is performed to determine whether the measurement electrode 51a and the reference electrode 51b are in contact with the subject 5.

FIG. 10 is a circuit block diagram showing a detailed configuration of the biological signal measurement device 10b in the electrical stimulation mode using the measurement electrode 51a. In FIG. 10, when the second switching element S2 is turned on, the second current source 54a is electrically connected to the measurement electrode 51a and the input terminal of the first amplifier circuit 52a. In the electrical stimulation mode, the current supplied from the second current source 54a is supplied from the measurement electrode 51a that contacts the subject 5 to the reference electrode 51b or the ground electrode 51c that also contacts the subject 5 through the subject 5 (not shown in FIG. 10). ).

Although not shown, in the electric stimulation mode using the reference electrode 51b, the fourth current source 54b is connected to the reference electrode 51b and the input terminal of the second amplifier circuit 52b by turning on the fourth switching element S4. Is done.

付与 The application of such electrical stimulation may have the effect of adjusting the physical condition of the subject 5. For example, an example has been reported in which electrical stimulation is applied to the vestibular organ in the inner ear of the subject 5 to improve the balance function of the body.

If one of the second current source 54a and the fourth current source 54b is a discharge type current source and the other of the second current source 54a and the fourth current source 54b is a suction type current source, the second current source It is also possible to perform electrical stimulation using both the source 54a and the fourth current source 54b. Further, each of the second current source 54a and the fourth current source 54b for performing the electrical stimulation may be configured by a current output type DA (Digital @ to @ Analog) converter (that is, a current output type DA converter). . FIG. 11 is a circuit block diagram illustrating a detailed configuration of the biological signal measurement device 10b according to such a modification.

In the biological signal measuring device 10b according to the modification shown in FIG. 11, the second current source 54a is a discharge type current source, and the fourth current source 54b is a suction type current source. In this case, in the electrical stimulation mode, when the second switching element S2 and the fourth switching element S4 are turned on, the biological signal measurement device 10b outputs the current discharged by the second current source 54a to the fourth current source 54b. Electrical stimulation can be provided by a configuration that sucks in through 5.

Further, the biological signal measuring device 10b shown in FIG. 11 is configured such that each of the second current source 54a and the fourth current source 54b in the biological signal measuring device 10b shown in FIGS. 9 and 10 is a current output type DA converter. This is realized by adding a decoder 57 for controlling the current values of the second current source 54a and the fourth current source 54b. The decoder 57 converts the first current control signals sc9 to sc0 input from the control unit 551 of the control device 55 into the second current control signals s2_p9 to s2_p0 output to the second current source 54a or the fourth current source 54b. To the second current control signals s4_n9 to s4_n0, which are output to the CPU.

First, the operation of the second current source 54a will be described. FIG. 12 is a diagram showing a detailed configuration of a second current source 54a constituted by a current output type DA converter. FIG. 13 is a diagram showing a truth value used for controlling such a second current source 54a. It is a table.

{For example, when performing electrical stimulation based on a current of 100 μA, the control device 55 outputs sc9, sc6, sc5, and sc2 = 1 (others are 0) as the first current control signal. The decoder 57 decodes this, and outputs s2_p9, s2_p6, s2_p5, and s2_p2 = 1 (others are 0) as the second current control signal. As a result, the current sources 54a_p6 (64 μA), the current sources 54a_p5 (32 μA), and the current sources 54a_p2 (4 μA) are turned on, and electrical stimulation based on a current of 100 μA is realized.

Next, the operation of the fourth current source 54b will be described. FIG. 14 is a diagram showing a detailed configuration of a fourth current source 54b constituted by a current output type DA converter. FIG. 15 is a diagram showing a truth value used to control such a fourth current source 54b. It is a table.

For example, when performing electrical stimulation based on a current of −100 μA, the control device 55 outputs sc6, sc5, and sc2 = 1 (others are 0) as the first current control signal. The decoder 57 decodes this, and outputs s4_n9, s4_n6, s4_n5, and s4_n2 = 1 (others are 0) as the second current control signal. As a result, the current sources 54b_p6 (−64 μA), the current sources 54b_n5 (−32 μA), and the current sources 54b_n2 (−4 μA) are turned on, and electrical stimulation based on a current of −100 μA is realized.

FIG. 16 summarizes the operation modes and the states of the switching elements as described above. FIG. 16 is a diagram showing the relationship between the operation mode and the state of the switching element. FIG. 16 shows two states of the switching element in the electric stimulation mode, a state corresponding to FIG. 10 and a state corresponding to FIG.

[Current waveform]
By the way, the current waveform for measuring the contact impedance (that is, the current waveform of the first current source 53a and the third current source 53b) and the current waveform for the electrical stimulation (that is, the current waveform of the second current source 54a and the fourth current source 54b) Current waveform). FIG. 17 is a diagram showing a current waveform for measuring contact impedance and a current waveform for electrical stimulation.

As shown in FIG. 17, the current for measuring contact impedance is, for example, an alternating current having a frequency of about 1 kHz. The alternating current having a frequency exceeding 100 Hz does not overlap the band of 0.5 Hz to 100 Hz which is the frequency range of the brain wave to be measured. Therefore, the measurement of the contact impedance and the measurement of the brain wave (biological signal) can be performed in parallel.

The current for electrical stimulation may be a direct current, an alternating current, or a noise current. The frequency of the alternating current may overlap the band of 0.5 Hz to 100 Hz, which is the frequency range of the brain wave to be measured. The noise current is, specifically, a current that forms white noise or a current that forms pink noise. White noise is noise whose frequency characteristic is constant (that is, noise power in a wide frequency band is almost constant), and can be generated by using, for example, thermal noise of a resistance element. White noise can also be generated by programming a waveform in the above-described current type DA converter. Pink noise is noise having characteristics in which noise power is inversely proportional to frequency. For example, pink noise can be generated using an FET whose channel width and channel length are adjusted. Pink noise can also be generated by programming a waveform in the above-mentioned current type DA converter.

As described above, the measurement of the contact impedance is performed to determine whether the measurement electrode 51a and the reference electrode 51b are in contact with the subject 5. Therefore, the value of the current for measuring the contact impedance (that is, the first current or the third current) is intended to be a weak value that does not stimulate the subject 5 as much as possible. On the other hand, the value of the current for electrical stimulation (that is, the second current or the fourth current) is intended to positively stimulate the subject 5. Therefore, the first amplitude of the first current is set to, for example, 1 μA or less, and the second amplitude of the second current is set to be larger than the first amplitude of the first current. Similarly, the third amplitude of the third current is set to, for example, 1 μA or less, and the fourth amplitude of the fourth current is set to be larger than the first amplitude of the third current. Note that the term “amplitude” may be read as the maximum amplitude (peak-to-peak value) when the amplitude is not constant.

The second current source 54a and the fourth current source 54b may be configured so that the subject 5 can select the type and amplitude of the current for electrical stimulation. Thus, the subject 5 can change the degree of the electrical stimulation according to his / her preference.

[Operation mode switching example]
Next, an example of switching operation modes will be described. FIG. 18 is a diagram illustrating an example of switching operation modes. In the following, an example of switching the operation mode in the first active electrode 60a will be described, but the same applies to switching of the operation mode in the second active electrode 60b.

において In FIG. 18, in the period from time t = 0 to time t = t1, brain wave measurement is performed in the contact impedance measurement mode. That is, the measurement of the brain wave and the measurement of the contact impedance are performed in parallel. The control unit 551 electrically connects the first current source 53a to the measurement electrode 51a by selectively turning on the first switching element S1 of the first switching element S1 and the second switching element S2, and changes the operation mode to the contact mode. Switch to impedance measurement mode. At this time, an AC current having a frequency of 1 kHz and an amplitude of 50 nA is output from the first current source 53a.

脳 In the period from the next time t = t1 to time t = t2, the measurement of the electroencephalogram is performed in the electric stimulation mode. That is, the measurement of the electroencephalogram and the application of the electrical stimulation are performed in parallel. The control unit 551 electrically connects the second current source 54a to the measurement electrode 51a by selectively turning on the second switching element S2 of the first switching element S1 and the second switching element S2, and changes the operation mode to electric. Switch to stimulation mode. At this time, a noise current that forms white noise with an amplitude of about 200 μA is output from the first current source 53a.

脳 In the period from the next time t = t2 to the time t = t3, brain wave measurement is performed in the contact impedance measurement mode. That is, the measurement of the brain wave and the measurement of the contact impedance are performed in parallel. The control unit 551 electrically connects the first current source 53a to the measurement electrode 51a by selectively turning on the first switching element S1 of the first switching element S1 and the second switching element S2, and changes the operation mode to the contact mode. Switch to impedance measurement mode. The first current source 53a outputs an alternating current having a frequency of 1 kHz and an amplitude of 50 nA.

において In the period after the next time t = t3, relatively strong electric stimulation is applied in the electric stimulation mode. The control unit 551 electrically connects the second current source 54a to the measurement electrode 51a by selectively turning on the second switching element S2 of the first switching element S1 and the second switching element S2, and changes the operation mode to electric. Switch to stimulation mode. At this time, an alternating current having a frequency of 1 kHz and an amplitude of about 600 μA is output from the first current source 53a.

For example, when electrical stimulation based on a strong current having an amplitude equal to or more than a predetermined value (for example, 100 μA) is performed, the electroencephalogram may not be measured well. Therefore, in such a case, the measurement of the brain wave is stopped. The stop of the measurement of the electroencephalogram may be realized by stopping the communication from the biological signal output unit 15 with the information processing device 20, or may be realized by stopping the display of the measurement result by the information processing device 20. You may. Thereby, the biological signal measurement system 100 can suppress display of an electroencephalogram that may not be properly measured.

[Component arrangement in active electrode]
Next, the component arrangement in the first active electrode 60a will be described. FIG. 19 is a diagram illustrating an example of a component arrangement in the first active electrode 60a. Note that the component arrangement on the second active electrode 60b is the same as that of the first active electrode 60a, and thus a detailed description is omitted.

As shown in FIG. 19, the measurement electrode 51a has a diameter of about 10 mm and is mounted on one main surface (a main surface on the back side in FIG. 19) of the substrate 58a smaller than the measurement electrode 51a. The first current source 53a and the second current source 54a are mounted on the other main surface (the front surface in FIG. 19) of the substrate 58a.

(4) The measurement electrode 51a and the input terminal of the first amplifier circuit 55a are electrically connected via a circular contact portion 59a having a diameter of about 1 mm located outside the substrate 58a. A first current source 53a is connected to a wiring that electrically connects the measurement electrode 51a and an input terminal of the first amplifier circuit 52a via a first switching element S1, and a second current source 54a is connected to a second switching element S2. Are electrically connected via

(4) The first amplifier circuit 52a is mounted such that the first amplifier circuit 52a is entirely located within a region of about 3 mm in width from the input side (left side in FIG. 19) to the output side (right side in FIG. 19).

(4) The first current source 53a is mounted so that the whole of the first current source 53a is located within a region having a width of about 1 mm from the input side to the output side. The second current source 54a is mounted so that the whole of the second current source 54a is located within a region having a width of about 2 mm from the input side to the output side.

において In the first active electrode 60a, the distance X between the first current source 53a and the first amplifier circuit 52a is 5 mm or less. More specifically, the distance X is a distance from the left end of the region where the first current source 53a is mounted to the left end of the region where the first amplifier circuit 52a is mounted. 19 (in other words, the direction in which the first current source 53a and the first amplifier circuit 52a are arranged) in FIG. When the distance X is shortened in this way, generation of unnecessary noise and jump of unnecessary noise are suppressed.

{Circle around (1)} In the first active electrode 60a, the distance between the second current source 54a and the first amplifier circuit 52a is also 5 mm or less. The definition of the distance between the second current source 54a and the first amplifier circuit 52a is, for example, the same as the distance X. When the distance between the second current source 54a and the first amplifier circuit 52a is shortened in this way, generation of unnecessary noise and jump of unnecessary noise are suppressed.

In the first active electrode 60a, if at least one of the distance between the first current source 53a and the first amplifier circuit 52a and the distance between the second current source 54a and the first amplifier circuit 52a is 5 mm or less. Good. As a result, an effect of suppressing the generation of unnecessary noise and the jump of unnecessary noise can be obtained.

[Display operation example of biological signal measurement system]
Next, a display operation example of the biological signal measurement system 100 will be described. FIG. 20 is a flowchart of a display operation example of the biological signal measurement system 100. FIG. 21 is a diagram illustrating a display example on the presentation unit 30 when the brain wave is measured in the contact impedance measurement mode. FIG. 22 is a diagram illustrating a display example on the presentation unit 30 when the brain wave is measured in the electric stimulation mode. FIG. 23 is a diagram illustrating a display example on the presentation unit 30 when the brain wave measurement is not performed in the electric stimulation mode.

First, the application processing unit 26 performs an initial process (S41). As shown in FIGS. 21 to 23, in the initial processing, the application processing unit 26 sets the measurement electrode 51a and the reference electrode 51b of the electroencephalograph 10 worn by the subject 5 on the electrode illustration unit 30c of the presentation unit 30. Displays the position of.

Next, the application processing unit 26 determines whether or not the current mode is the contact impedance measurement mode (S42). When the operation of instructing the contact impedance measurement mode is performed on the operation button 41, the application processing unit 26 transmits the notification signal transmitted from the electroencephalograph 10 in response to the operation of instructing the contact impedance measurement mode. 21 to determine whether or not it has been acquired. Further, when an operation for instructing the contact impedance measurement mode is performed on a user interface (not shown) included in the information processing device 20, the application processing unit 26 determines whether such an operation has been performed. I do.

When determining that the current mode is the contact impedance measurement mode (YES in S42), the application processing unit 26 displays “measurement of contact impedance” on the measurement information display unit 30a of the presentation unit 30 as shown in FIG. (S43). Then, the application processing unit 26 measures the contact impedance of the reference electrode 51b (S44). The application processing unit 26 extracts and demodulates a voltage around 1 kHz obtained from the biological signal output unit 15 in a state where the second active electrode 60b including the reference electrode 51b is in the contact impedance measurement mode, and applies the obtained voltage value. By dividing by the obtained current value, the contact impedance of the reference electrode 51b is measured.

Similarly, the application processing unit 26 measures the contact impedance of the measurement electrode 51a (S45). Then, as shown in FIG. 21, the application processing unit 26 displays the measured contact impedance of the reference electrode 51b and the measured electrode 51a on the contact impedance display unit 30e of the presentation unit 30 (S46).

On the other hand, when determining that the current mode is not the contact impedance measurement mode (NO in S42), the application processing unit 26 determines whether the current mode is the electrical stimulation mode (S47). When an operation for instructing the electric stimulation mode is performed on the operation button 41, the application processing unit 26 transmits a notification signal transmitted from the electroencephalograph 10 in response to the operation for instructing the electric stimulation mode by the operation signal acquisition unit 21. It is determined whether or not it has been acquired. In addition, when an operation for instructing the electric stimulation mode is performed on a user interface (not illustrated) included in the information processing device 20, the application processing unit 26 determines whether such an operation has been performed. .

When determining that the current mode is the electric stimulation mode (YES in S47), the application processing unit 26 displays “electric stimulation” on the measurement information display unit 30a of the presentation unit 30 as shown in FIGS. (S48). Then, the application processing unit 26 acquires the setting (type (DC, AC, or noise) and amplitude) of the electric stimulation current (S49). The setting of the electric current for electrical stimulation is determined based on, for example, an operation on the operation button 41 of the subject 5 and is transmitted from the electroencephalograph 10 to the information processing device 20, but based on the operation on the information processing device 20. It may be determined. Then, as shown in FIGS. 22 and 23, the application processing unit 26 displays the acquired current setting on the current setting information display unit 30d in the presentation unit 30 (S50).

After step S46, in the case of NO in step S47, and after step S50, it is determined whether or not brain wave measurement is being performed (S51). For example, in the case of the contact impedance mode, and in the case where the amplitude of the current is set to be less than the predetermined value in the electric stimulation mode, the application processing unit 26 determines that the electroencephalogram is being measured (YES in S51).

In this case, as shown in FIG. 21 and FIG. 22, the application processing unit 26 displays “Measurement of EEG” on the measurement information display unit 30a of the presentation unit 30 (S52).

Then, as shown in FIGS. 21 and 22, the application processing unit 26 displays a waveform of a biological signal (here, a waveform of an electroencephalogram) obtained from the biological signal measurement device 10b on a waveform display unit 30b of the presentation unit 30. It is displayed (S53).

On the other hand, for example, when the amplitude of the current is set to a predetermined value or more in the electric stimulation mode, the application processing unit 26 determines that the electroencephalogram measurement is not being performed (NO in S51). In this case, as shown in FIG. 23, since the brain wave measurement of the subject 5 is not performed, the waveform display unit 30b of the presentation unit 30 does not display the waveform of the brain wave, but displays dummy voltage data. The waveform of the current used for the electrical stimulation may be displayed on the waveform display unit 30b of the presentation unit 30.

As described above, in the biological signal measurement system 100, the presentation information unit 30 displays the measurement information display unit 30a, the waveform display unit 30b, the electrode display unit 30c indicating the position of the electrode, the current setting information display unit 30d, , The contact impedance display section 30e is displayed, and much information can be understood at a glance.

[Operation example including motion measurement mode of biological signal measurement system]
As described above, the biological signal measurement device 10b can perform the operation in the motion measurement mode for measuring the motion of the subject 5 using the output signal of the acceleration sensor 56. That is, it can be said that the control unit 551 of the control device 55 has the motion measurement mode, the contact impedance measurement mode, and the electric stimulation mode. The contact impedance measurement mode is a mode for measuring a biological signal while measuring contact impedance using a current for contact impedance measurement (that is, the first current or the third current). Is a mode in which electric stimulation is applied to the subject 5 using the electric current for electric stimulation (that is, the second current or the fourth current).

The operation in the motion measurement mode is performed, for example, in parallel with the contact impedance measurement mode or the electrical stimulation mode. FIG. 24 is a diagram showing an operation example including the motion measurement mode of such a biological signal measurement system, and the movement of the subject is measured in parallel with the operation shown in the flowchart of FIG. 20 (S61).

For example, when the subject 5 walks after performing the electrical stimulation for about 30 minutes, a case is known in which the stride, the walking speed, the step time, and the directionality are improved as compared to before the electrical stimulation is performed. I have. FIG. 25 is a diagram illustrating an improvement in the walking motion of the subject 5 by the electrical stimulation. When the subject 5 walks forward, when the electric stimulus is not applied, the landing foot draws a trajectory flowing to the right, whereas when the electric stimulus is applied, the walking direction is straight and the stride is wide, and the walking speed is increased. Has the effect of being improved. If the history of the electrical stimulation (that is, the operation history in the electrical stimulation mode) and the history of the walking operation (that is, the history of the measurement result in the motion measurement mode) are stored in association with each other by the biological signal measurement device 10b, It can be used to grasp the relationship between the stimulus and the walking motion.

By the way, if the current source for performing the electrical stimulation described above is realized by the current output type DA converter, the control unit 551 of the control device 55 can finely control the current value for the electrical stimulation. Therefore, the control unit 551 may control the electric stimulation current based on the measurement result of the movement of the subject 5. In this case, the measurement result of the movement may be a measurement result (history) of a past movement before the electric stimulation to be performed, or the measurement result of the movement may be immediately used for the electric stimulation as shown in FIG. May be reflected in the current value of the current.

The control unit 551 may control the electric stimulation current based on the biological signal measured in the contact impedance measurement mode. In this case, the movement biosignal may be a past biosignal (history of the biosignal) measured before the electric stimulation to be performed, or the measurement result of the biosignal is immediately changed to the electric stimulation current. May be reflected in the current value.

The control unit 551 may control the current for electrical stimulation based on both the measurement result of the movement and the measurement result of the biological signal. The electric stimulation current may be controlled based on at least one of the movement of the subject 5 measured in the motion measurement mode and the biological signal measured in the contact impedance measurement mode.

[Effects]
The biological signal measuring device 10b is realized, for example, as an active electrode. Such an active electrode measures a measurement electrode 51a that comes into contact with a living body, a first amplification circuit 52a to which a first biological signal detected by the measurement electrode 51a is input, and a first current for measuring contact impedance. It includes a first current source 53a for flowing the living body through the electrode 51a, and a second current source 54a for flowing a second current for applying electric stimulation to the living body through the measurement electrode 51a. The measurement electrode 51a is an example of a first electrode.

アクティブ Such an active electrode can apply an electrical stimulus to a living body via a measuring electrode 51a for detecting a first biological signal.

Further, for example, the active electrode further includes a first switching element S1 for turning on and off an electrical connection between the first current source 53a and the measurement electrode 51a, and an electrical connection between the second current source 54a and the measurement electrode 51a. A second switching element S2 for turning on and off the connection.

Such an active electrode can selectively perform an operation in a contact impedance measurement mode for measuring the contact impedance of the measurement electrode 51a and an operation in an electric stimulation mode for applying electric stimulation to a living body via the measurement electrode 51a. .

Also, for example, the first current is an AC current having a first amplitude, the second current is a DC current, an AC current, or a noise current, and the second amplitude of the second current is larger than the first amplitude. large.

アクティブ Such an active electrode can effectively apply an electric stimulus to a living body through the measurement electrode 51a by a current having a larger amplitude than that at the time of measuring the contact impedance.

Also, for example, the first amplitude is 1 μA or less.

アクティブ Such an active electrode can reduce the electrical stimulation given to the living body when measuring the contact impedance of the measurement electrode 51a.

In addition, for example, the active electrode further includes a reference electrode 51b that comes into contact with a living body, a second amplifier circuit 52b to which a second biological signal detected by the reference electrode 51b is input, and a third electrode for measuring contact impedance. A third current source 53b for flowing a current to the living body via the reference electrode 51b, and a fourth current source 54b for flowing a fourth current for applying electrical stimulation to the living body to the living body via the reference electrode 51b. Prepare. The reference electrode 51b is an example of a second electrode.

Such an active electrode can apply an electrical stimulus to a living body via a reference electrode 51b for detecting a second biological signal.

Further, for example, the active electrode further includes a third switching element S3 for turning on and off an electrical connection between the third current source 53b and the reference electrode 51b, and an electrical connection between the fourth current source 54b and the reference electrode 51b. And a fourth switching element S4 for turning on and off the connection.

Such an active electrode can selectively perform operation in the contact impedance measurement mode for measuring the contact impedance of the reference electrode 51b and operation in the electric stimulation mode for applying electric stimulation to the living body via the reference electrode 51b. .

Also, for example, the third current is an AC current having a third amplitude, the fourth current is a DC current, an AC current, or a noise current, and the fourth amplitude of the fourth current is larger than the third amplitude. .

アクティブ Such an active electrode can effectively apply an electric stimulus to a living body via the reference electrode 51b by a current having a larger amplitude than that at the time of measuring the contact impedance.

第三 Further, for example, the third amplitude is 1 μA or less.

アクティブ Such an active electrode can reduce the electrical stimulation given to the living body when measuring the contact impedance of the reference electrode 51b.

Also, for example, at least one of the distance between the first current source 53a and the first amplifier circuit 52a and the distance between the second current source 54a and the first amplifier circuit 52a is 5 mm or less.

(4) As a result, the effect of suppressing the generation of unnecessary noise and the jump of unnecessary noise can be obtained.

Also, for example, the second current source 54a is configured by a current output type DA converter.

Such an active electrode can control the current value of the electric stimulation current.

Further, for example, the first current source 53a and the second current source 54a are realized by a single current source circuit.

With such an active electrode, a single current source circuit can be used as the first current source 53a and the second current source 54a.

Further, for example, the active electrode further includes an acceleration sensor 56.

アクティブ Such an active electrode can measure the movement of the subject 5 based on the output signal of the acceleration sensor.

The electroencephalograph 10 also includes the active electrode described above and a mounting part 40 provided on the living body and provided with the measurement electrode 51a.

Such an electroencephalograph 10 can give an electric stimulus to the living body via the measurement electrode 51a for detecting the first biological signal.

脳 In addition, for example, the electroencephalograph 10 further includes an acceleration sensor 56.

Such an electroencephalograph 10 can measure the movement of the subject 5 based on the output signal of the acceleration sensor.

Further, for example, the acceleration sensor 56 is provided on the active electrode.

Such an electroencephalograph 10 can measure the movement of the subject 5 based on the output signal of the acceleration sensor provided on the active electrode.

The control device 55 that controls the active electrode includes a control unit 551 that selectively connects the first current source 53a and the second current source 54a to the measurement electrode 51a.

The control device 55 can selectively perform operation in the contact impedance measurement mode for measuring the contact impedance of the measurement electrode 51a and operation in the electric stimulation mode for applying electric stimulation to the living body via the measurement electrode 51a. it can.

制御 Furthermore, for example, the control device 55 further includes an acceleration sensor 56. The control unit 551 is a motion measurement mode for measuring the motion of the subject 5 using the output signal of the acceleration sensor 56, and a contact impedance measurement mode for measuring the first biological signal while measuring the contact impedance using the first current. And an electrical stimulation mode for applying the electrical stimulation to the subject 5 using the second current. The second current in the electrical stimulation mode is controlled based on at least one of the movement of the subject 5 measured in the movement measurement mode and the first biological signal measured in the contact impedance measurement mode.

制御 Such a control device 55 can control the second current in the electric stimulation mode based on at least one of the movement of the subject 5 and the first biological signal.

は In addition, the control method of the active electrode selectively connects the first current source 53a and the second current source 54a to the measurement electrode 51a.

Such a control method can selectively perform operation in the contact impedance measurement mode for measuring the contact impedance of the measurement electrode 51a and operation in the electric stimulation mode for applying electric stimulation to the living body via the measurement electrode 51a. .

In addition, for example, the control method further includes a motion measurement mode for measuring the motion of the subject 5 using an output signal of the acceleration sensor 56 provided in the active electrode, and a first biological signal while measuring contact impedance using the first current. And an electrical stimulation mode for applying electrical stimulation to the subject 5 using the second current. The second current in the electrical stimulation mode is controlled based on at least one of the movement of the subject 5 measured in the movement measurement mode and the first biological signal measured in the contact impedance measurement mode.

According to such a control method, the second current in the electric stimulation mode can be controlled based on at least one of the movement of the subject 5 and the first biological signal.

(Other embodiments)
The embodiment has been described above, but the present invention is not limited to such an embodiment.

For example, in the above embodiment, the ear-hung type electroencephalograph was described, but the present invention may be another type of electroencephalograph such as a headset type electroencephalograph worn on the head of the subject. . Further, the present invention may be realized as a biological signal measuring device other than an electroencephalograph, for example, an electrocardiograph for detecting an electrocardiogram signal (Electrocardiogram (ECG) signal) from an electrode attached to a body, a hand, a foot or the like. It may be realized as.

The circuit configuration described in the above embodiment is an example, and the present invention is not limited to the above circuit configuration. That is, similarly to the above circuit configuration, a circuit capable of realizing the characteristic function of the present invention is also included in the present invention. For example, an element in which an element such as a switching element (transistor), a resistor, or a capacitor is connected to a certain element in series or in parallel to the extent that a function similar to the above circuit configuration can be realized is also included in the present invention. included.

In addition, in the above embodiment, another processing unit may execute the process executed by the specific processing unit. Further, the order of the plurality of processes may be changed, or the plurality of processes may be executed in parallel.

In addition, in the above embodiment, each component may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

各 Also, each component may be realized by hardware. For example, a component such as a control unit may be a circuit (or an integrated circuit). These circuits may constitute one circuit as a whole, or may be separate circuits. Each of these circuits may be a general-purpose circuit or a dedicated circuit.

The general or specific aspects of the present invention may be realized by a recording medium such as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM. Further, the present invention may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

For example, the present invention may be realized as a control method of an active electrode, or may be realized as a program for causing a computer to execute such a control method. Further, the present invention may be realized as a non-transitory computer-readable recording medium on which such a program is recorded.

The biological signal measurement system may be realized as a single device, or may be realized by a plurality of devices. When the biological signal measurement system is realized by a plurality of devices, the components included in the biological signal measurement system described in the above embodiment may be distributed to the plurality of devices in any manner.

In addition, one or more aspects in which various modifications conceived by those skilled in the art are applied to the present embodiment, and a form constructed by combining constituent elements in different embodiments are also possible unless departing from the spirit of the present invention. May be included in the range.

5 subjects (living body)
10 EEG 40 Mounting part 51a Measurement electrode (first electrode)
51b Reference electrode (second electrode)
52a first amplifier circuit 52b second amplifier circuit 53a first current source 53b third current source 54a second current source 54b fourth current source 551 control unit 56 acceleration sensor S1 first switching element S2 second switching element S3 third switching Element S4 Fourth switching element

Claims

A first electrode in contact with the living body,
A first amplification circuit to which a first biological signal detected by the first electrode is input,
A first current source for flowing a first current for measuring contact impedance to the living body through the first electrode,
A second current source for flowing a second current for applying electrical stimulation to the living body to the living body via the first electrode.
further,
A first switching element for turning on and off the electrical connection between the first current source and the first electrode,
The active electrode according to claim 1, further comprising: a second switching element that turns on and off an electrical connection between the second current source and the first electrode.
The first current is an alternating current having a first amplitude,
The second current is a direct current, an alternating current, or a noise current,
The active electrode according to claim 1, wherein the second amplitude of the second current is larger than the first amplitude.
The active electrode according to claim 3, wherein the first amplitude is 1 μA or less.
further,
A second electrode contacting the living body,
A second amplification circuit to which a second biological signal detected by the second electrode is input,
A third current source for flowing a third current for measuring contact impedance to the living body through the second electrode,
The active electrode according to any one of claims 1 to 4, further comprising: a fourth current source configured to supply a fourth current for applying electrical stimulation to the living body to the living body via the second electrode.
further,
A third switching element for turning on and off the electrical connection between the third current source and the second electrode,
The active electrode according to claim 5, further comprising: a fourth switching element that turns on and off an electrical connection between the fourth current source and the second electrode.
The third current is an alternating current having a third amplitude,
The fourth current is a direct current, an alternating current, or a noise current,
The active electrode according to claim 5, wherein a fourth amplitude of the fourth current is larger than the third amplitude.
The active electrode according to claim 7, wherein the third amplitude is 1 μA or less.
9. The device according to claim 1, wherein at least one of a distance between the first current source and the first amplifier circuit and a distance between the second current source and the first amplifier circuit is 5 mm or less. An active electrode according to claim 1.
The active electrode according to any one of claims 1 to 9, wherein the second current source is configured by a current output type DA (Digital to Analog) converter.
The active electrode according to any one of claims 1 to 9, wherein the first current source and the second current source are realized by a single current source circuit.
The active electrode according to any one of claims 1 to 11, further comprising an acceleration sensor.
An active electrode according to any one of claims 1 to 11,
An electroencephalograph, comprising: a mounting portion provided with the first electrode, which is mounted on the living body.
The electroencephalograph according to claim 13, further comprising an acceleration sensor.
The electroencephalograph according to claim 14, wherein the acceleration sensor is provided by the active electrode.
A control device for controlling an active electrode,
The active electrode is
A first electrode in contact with the living body,
A first amplification circuit to which a first biological signal detected by the first electrode is input,
A first current source for flowing a first current for measuring contact impedance to the living body through the first electrode,
A second current source for flowing a second current for applying electrical stimulation to the living body to the living body via the first electrode,
The control device includes a control unit that selectively connects the first current source and the second current source to the first electrode.
The control device further includes an acceleration sensor,
The control unit is a motion measurement mode for measuring the motion of the living body using the output signal of the acceleration sensor, a contact for measuring the first biological signal while measuring the contact impedance using the first current Impedance measurement mode, and has an electrical stimulation mode to give the electrical stimulation to the living body using the second current,
The second current in the electrical stimulation mode is controlled based on at least one of the movement of the living body measured in the movement measurement mode and the first biological signal measured in the contact impedance measurement mode. Item 17. The control device according to Item 16.
A method for controlling an active electrode, comprising:
The active electrode is
A first electrode in contact with the living body,
A first amplification circuit to which a first biological signal detected by the first electrode is input,
A first current source for flowing a first current for measuring contact impedance to the living body through the first electrode,
A second current source for flowing a second current for applying electrical stimulation to the living body to the living body via the first electrode,
The control method is a control method for selectively electrically connecting the first current source and the second current source to the first electrode.
The control method further includes a motion measurement mode for measuring the motion of the living body using an output signal of an acceleration sensor included in the active electrode, and the first biological signal while measuring the contact impedance using the first current. A contact impedance measurement mode for measuring the, and an electrical stimulation mode for applying the electrical stimulation to the living body using the second current,
The second current in the electrical stimulation mode is controlled based on at least one of the movement of the living body measured in the movement measurement mode and the first biological signal measured in the contact impedance measurement mode. Item 19. The control method according to Item 18.
A program for causing a computer to execute the control method according to claim 18 or 19.