JPH0975313A - Manipulating device for biological signal measurement and brain magnetic field measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide motion related biological information with a satisfactory S/N by providing a manipulating means composed of materials not to electromagnetically exert an adverse influence upon a biological signal inside a magnetism shield chamber and connecting optical fibers to a light emitting element and a light receiving element outside the magnetism shield chamber. SOLUTION: At a magnetism shield chamber 3 covered with plates 2 composed of magnetism shield materials, a manipulating member 7 at the top end part of a manipulating means 5 is moved upward and displaced with the tip of a forefinger 8 of the hand of an examinee as a human body to measure brain magnetic fields so that a light passage 11 can be opened for introducing light from one-side terminal parts 9a and 9b of a pair of optical fibers 9 and 10. Then, light from a light emitting element 12 provided at another-side terminal part 9b of optical fiber 9 is guided from the one-side terminal part 9a of optical fiber 9 through the light passage 11 to the one-side terminal part 10a of the other optical fiber 10. At another-side terminal part 10b of optical fiber 10, it is detected by a light receiving element 13 that the light passage 11 is not shielded. In this case, the other-side terminal parts 9b and 10b of optical fibers 9 and 10 are arranged outside rather than the plates 2 of magnetism shield chamber 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for measuring a biological signal, for example, a brain magnetic field generated from a human brain, and is related to a motion of a subject, that is, a motion-related brain magnetic field MRF (Movement). The present invention relates to an operating device for measuring a biological signal, which can be advantageously carried out for measuring a Relate Field, and to a brain magnetic field measuring device using the operating device.

[0002]

2. Description of the Related Art Conventionally, in order to measure a movement-related potential of the brain, the output of an electroencephalograph is taken out by using an electromyogram when a subject moves a finger as a trigger pulse. In order to obtain an electromyogram, a pair of electrodes are placed on the epidermis just above the muscle abdomen of the contracting muscle in order to measure the action potential associated with the contraction of the muscle, and the electromyogram when voluntary movement is performed. After recording, the signal obtained from the electrode is amplified and used after rectification, and when the electromyogram signal after the rectification exceeds a predetermined threshold value,
The pulse for use as a trigger is generated, and the movement-related potential obtained by the electroencephalograph when the pulse is obtained is measured.

[0003]

In this prior art, a magnetic field is generated by the current flowing through the electrodes used for obtaining the electromyogram, and the magnetic field is mixed into the output of the electroencephalograph as noise. Among the exercise-related cerebral magnetic fields, the exercise preparation cerebral magnetic field, which particularly occurs before exercise, has a very low frequency component, so that the SN ratio is greatly reduced by the mixing of the noise.

Further, in this prior art, since the waveform of the muscle discharge during voluntary movement is different every time, the temporal relation between the movement and the trigger pulse is not constant, and therefore the electroencephalograms obtained from the electroencephalographs for multiple times are added. It is impossible to find the average accurately.

Further, in this prior art, a detectable electromyographic signal is obtained only when the finger is moved by a large amount, for example, by 5 mm or more, and the electromyogram of the finger to be moved, for example, the index finger, can be obtained without moving the index finger. This occurs when the thumb is moved, and this also makes it difficult to obtain an accurate trigger pulse.

It is an object of the present invention to obtain a motion-related biological signal, for example, a motion-related brain magnetic field, with a good SN ratio, and more precisely, a time relationship between the motion and the biological signal. An object of the present invention is to provide a signal measuring operating device and a brain magnetic field measuring device using the same.

[0007]

The present invention comprises: (a) an operation made of a material which is provided in the vicinity of a biological signal measuring device for measuring a biological signal and which does not electromagnetically adversely affect the biological signal to be measured. And an operating member main body that forms an optical path, and an operating member that is made of a material that blocks light and that is relatively displaced with respect to the main body and removably enters the optical path to block the optical path. (B) a pair of optical fibers, one end of each of which is arranged on both sides of the operation member of the optical path, and the other end of which is provided separately from the biomagnetism measuring device; (D) An operating device for measuring a biological signal, comprising: a light emitting element that guides light to the other end; and (d) a light receiving element that receives light from the other end of the other optical fiber. According to the present invention, the operating means main body forming the optical path and the operating member capable of blocking the optical path are made of a material that does not electromagnetically adversely affect the biological signal to be measured, such as ABS resin. The operating means is made of a material such as synthetic resin or ceramic, and is provided, for example, in a magnetically shielded room where the electric field may be shielded, and the light from the light emitting element is guided to the other end of one optical fiber. The light from one end of the one optical fiber is guided to the one end of the other optical fiber by being blocked or not blocked by the operating member, and is guided to the one end of the other optical fiber. The emitted light is guided to the light receiving element from the other end. The light emitting element and the light receiving element are provided outside the magnetically shielded room. Therefore, in the magnetically shielded room, it is possible to prevent electromagnetic noise from being mixed in with the biological signal of the subject such as a human being, and the biological signal SN
The ratio can be improved. According to the invention, the operation member is operated by the subject, and the displacement amount for operating the operation member so as to interrupt the light path or guide the light to the light path may be extremely small, for example, a single Since the diameter of the core of the optical fiber may be any, this displacement amount may be small and does not adversely affect the measurement of the biological signal. Further, by operating the operating member, the time relationship between the motion for operating the operating member and the electric signal output of the light receiving element obtained by the motion is accurately matched.

Further, according to the present invention, the operation means main body has a width that can be gently covered by hand with the vicinity of the tip of the finger placed on the upper part of the operation member, and at least the vicinity of the wrist is placed. It is characterized in that it is formed in a substantially elongated shape having a certain length. According to the present invention, the operation member is operated near the tip of the human index finger, and in this operation state, the operation means main body has a width that can be gently covered with the hand, and The vicinity of the wrist has a length to be mounted on the operation means main body, and is formed in a substantially elongated shape, whereby the operator can smoothly operate the operation member.

Further, according to the present invention, the operating means main body has a substantially rectangular parallelepiped outer shape, and has a support body having a storage recess formed at the distal end in the longitudinal direction, and the operation member is housed in the storage recess and the operating member is moved up and down. Is movably inserted into the optical fiber, the one ends of the pair of optical fibers are fixed along the longitudinal direction of the support, and each of the one ends has a holding member facing each other on both sides of the operating member. And According to the invention, the retainer member is accommodated in the accommodation recess of the support body of the operation means main body, and the one end portions of the pair of optical fibers are fixed to the retainer member along the longitudinal direction of the support body. Since it is easy to guide and install a pair of optical fibers, it does not interfere with the work of measuring a biomedical signal.

The present invention also provides (a) a magnetically shielded room, (b) a brain magnetic field measurement assembly provided in the magnetically shielded room, wherein (b1) a cryogenic container covering at least the skull, and (b2) the low temperature container. A plurality of superconducting quantum interference magnetometers provided in a container, each superconducting quantum interference magnetic flux being distributed outside the skull and having a brain magnetic field detection coil for detecting a weak magnetic field from the brain. A brain magnetic field measurement assembly including a meter, and (c) an operating means which is provided in the shielded room and is made of a material that does not electromagnetically affect the detection of the brain magnetic field,
(C1) made of an operation means main body forming an optical path, and (c2) made of a material for shielding light, and relatively displaced with respect to the main body,
An operating means having an operating member that releasably enters the optical path and blocks the optical path, and (d) one end portion is arranged on both sides of the operating member of the optical path and the other end portion of the magnetic shield chamber is provided. A pair of optical fibers extending outwardly; (e) a light emitting element for guiding light to the other end of one optical fiber; (f) receiving light from the other end of the other optical fiber A light-receiving element, (g) a memory for storing the output of the magnetometer, and (h) a memory for storing the output of the magnetometer before and after light is received or blocked in response to the output of the light-receiving element. And a control means for controlling the magnetic field. Further, the present invention is characterized by further including means for averaging the outputs of a plurality of times stored in the memory for each magnetic flux meter over time. According to the present invention, the weak brain magnetic field of the human brain is measured by the brain magnetic field measurement assembly, the output of the superconducting quantum interference magnetometer thus obtained is stored in the memory, and each time when it is operated by the operating member. Accurate brain magnetic field waveforms for each magnetometer can be obtained by storing the output for each of them in a memory and further performing the averaging thereof.

[0011]

1 is a perspective view showing a usage state of an operating apparatus 1 for measuring brain magnetic field according to an embodiment of the present invention. In the magnetically shielded room 3 covered by the plate 2 made of magnetically shielded material, the operating member 7 provided at the tip 6 of the operating means 5 is pointed by the hand 4 of the subject, which is the human body whose brain magnetic field is to be measured. By moving upward at the tip of the optical fiber 8, the end portions 9a, 9 of the pair of optical fibers 9, 10 are
The light path 11 for guiding the light from b is opened. As a result, light from a light emitting element 12 such as a light emitting diode provided on the other end 9b of one optical fiber 9 passes through the optical path 11 from the one end 9a of the optical fiber 9 and then the other optical fiber 10 of the other optical fiber 10. It is guided to the one end 10a. Optical fiber 10
At the other end 10b of the light receiving element 13, light is received by a light receiving element 13 such as a phototransistor, and it is detected that the optical path 11 is no longer blocked. The magnetically shielded room 3
It is surrounded by a plate 2, the ferromagnetic material of which is
For example, permalloy is used, and the magnetically shielded chamber 3 is surrounded by a conductive plate that is grounded to form an electric field shielded chamber in the same manner.

The other ends 9b, 10b of the optical fibers 9, 10
Are arranged outside the plate 2 of the magnetically shielded chamber 3. Therefore, the electromagnetic noise due to the light emitting element 12 and the light receiving element 13 is prevented from being mixed into the brain magnetic field to be measured, and the SN ratio of the detected brain magnetic field is improved.

FIG. 2 is a sectional view showing a simplified overall configuration of the brain magnetic field measuring apparatus 14 provided with the apparatus 1 as viewed from the side, and FIG. 3 shows a state of use of the brain magnetic field measuring apparatus 14. It is a perspective view. The brain magnetic field of the head 17 is detected by the magnetic field measuring assembly 18 while seated on the bed 16. The subject is designated by the reference numeral 15.

The brain magnetic field measurement assembly 18 for detecting the brain magnetic field of the head 17 of the subject 15 comprises a pair of arms 19
Is attached to the free end of the so as to be swingable by being angularly displaced about a horizontal axis. The base end of the arm 19 is provided on the side wall 20 which is the plate 2 of the magnetically shielded room 3 in the building so as to be swingable around the horizontal axis. A pair of columns 21 is fixed to the ceiling plate of the magnetically shielded room 3 to hold the arm 19,
Configure a portal gantry.

The bed 16 includes a backrest 22 and a seat 2
The operation means 1 is placed on the handrail 24 and is operated by the hand 4.

FIG. 4 is a plan view of the operating means 5, and FIG. 5 is a side view thereof. The operating means 5 is an operating means body 25.
And an operation member 26. The operation means main body 25 basically has a support 27 and a holding member 28 for holding the optical fibers 9 and 10. The support body 27 includes a base body 29 and a lid body 30 fixed to the upper portion thereof. Support 27
Has a substantially rectangular parallelepiped outer shape, and has a tip portion in the longitudinal direction which is the left-right direction in FIGS. 4 and 5 (see FIGS. 4 and 5).
A storage recess 31 is formed at the left end of the storage recess 31.

The operating means main body 25 has a width W1 that can be gently covered by the hand 4 with the vicinity of the tip of the index finger 8 placed on the upper part of the operating member 26, and at least a wrist having a carpal bone. The length L1 of about 32 is mounted. In this embodiment of the invention, the width W1 = 60 mm,
The length L1 may be 170 mm and the height H1 may be 25 mm. The length L2 and the width W2 of the operating member 26 are L2 =
W2 = 20 mm may be sufficient, and distance L3 = 120 mm from the end part of the operation means main body 25 may be sufficient.

FIG. 6 is a sectional view taken along section line VI-VI in FIG. 4, and FIG. 7 is a sectional view taken along section line VII-VII in FIG. The holding member 28 is housed and fixed in the housing recess 31 formed in the support body 27 as described above, and the optical path 1 formed in the support body 27.
An operation member 26 is provided so that the control unit 1 can be shut off.

FIG. 8 is a plan view of the holding member 28, and FIG.
Is a side view of the holding member 28, and FIG. 10 is a front view of the holding member 28. With reference to these drawings, the holding member 28 is made of a material that shields light similarly to the operating member 26, and holding holes 32 and 33 into which the one ends 9a and 10a of the optical fibers 9 and 10 are inserted are provided. It is fixed by screws 34 and 35. One end 9a of each optical fiber 9,10,
10a is an end member 36, 37 including a lens and a reflecting mirror.
Is adjusted so that the light at each end 9a, 10a passes through the optical path 11 by adjusting bolts 38, 39. The axes of the holding holes 32 and 33 are parallel within one imaginary plane 40.

In the base body 29 of the support body 27, the insertion hole 4 corresponding to the holding holes 32 and 33 at the tip thereof is provided.
1, 42 are formed, and the optical fibers 9 and 10 are inserted therein. The holding member 28 has a guide hole 4 facing the optical path 11.
3 is formed.

The operation member 26 includes an operation piece 44 operated by the index finger 8 and a flange 45 protruding to both sides.
And a light-shielding piece 46 that can be inserted into the guide hole 43 to block the optical path 11, and are integrally molded. One fastener 47 is fixed to the upper portion of the operation piece 44. The other tubular fastener 48 into which the finger 8 can be inserted can be detachably connected to the one fastener 47. These fasteners 47, 48
Is commercially available under the tradename Velcro or Velcro.

The flange 45 exists in the storage recess 31 below the lid 30 and serves to prevent the operating member 26 from coming off.
When the light blocking piece 46 is in contact with the bottom 49 of the guide hole 43, the optical path 11 is blocked and the one end portion 9 of the optical fiber 9 is blocked.
The light from a through the end member 36 is blocked by the light shielding piece 46 and is not transmitted to the end member 37 of the one end 10a of the other optical fiber 10. When the index finger 8 is raised and the operation member 26 is raised, the end member 3 is passed through the optical path 11.
Light from 6 can be directed to the other end member 37. The maximum amount of displacement for raising the operating member 26 is as indicated by reference numeral H2 in FIG.
Is the distance to contact the lower surface of the lid 30. When the optical fibers 9 and 10 are composed of a single optical fiber, the maximum displacement amount H2 may be equal to or larger than the diameter of its core. Therefore, the displacement amount required to pass the light through the optical path 11 is, for example, 2
It may be less than ~ 3 mm. As described above, the displacement of the index finger 8 is small, which is advantageous because it does not adversely affect the brain magnetic field to be measured.

FIG. 11 is a simplified view of the principle of the embodiment of the present invention shown in FIGS. The light emitting element 12 is driven by the drive circuit 51, the light thereof is guided from the other end 9b of the optical fiber 9 to the one end 9a, and the operating member 26 is lifted by the index finger 8, so that the light passes through the optical path 11. The light is guided to one end 10a of the other optical fiber 10 and received by the light receiving element 13 from the other end 10b. Thus, the output terminal 5 of the light receiving element 13
From 2, an electric signal output, which is a trigger pulse indicating that light is received by the light receiving element 13 or that light is no longer received, is derived.

Each component constituting the operating means 5 is made of a material such as AB which does not adversely affect the brain magnetic field to be measured.
It is made of a synthetic resin material such as S resin and a material such as ceramic.

FIG. 12 is a simplified longitudinal sectional view of a portion of the brain magnetic field measurement assembly 18. Head 17 of subject 15
The cryogenic container 53 that covers at least the skull is configured such that a vacuum heat insulating layer 56 is interposed between an outer tank 54 and an inner tank 55, and liquid helium 57 is stored in the inner tank 55, and superconductivity is maintained. A quantum interference (abbreviated as SQUID) magnetometer 58 is formed by immersion.

A plurality of magnetometers 58 are arranged so as to cover the skull. Each magnetometer 58 includes a detection coil 59 for detecting a brain magnetic field and a coupling coil 60 connected to the detection coil, and each coupling coil 60 is magnetically coupled to the SQUID element 61. The SQUID element 61 is, for example, of a so-called direct current type, and has a structure having two Josephson couplings in a superconducting ring. A direct current constant current source is connected to the SQUID element, and a current from the constant current source is connected. Is S
It is supplied to the QUID element 61. The output voltage of the SQUID element 61 is amplified by the amplifier, is given to the synchronous detection circuit 64 of the electric circuit 63 provided outside the magnetically shielded room 3 via the line 62, and is converted into a digital value by the analog / digital conversion circuit. The converted digital signal corresponding to the weak magnetic field is input to the processing circuit 66 realized by a microcomputer or the like. As another embodiment of the present invention, instead of the DC type SQUID element 61, a parallel resonance circuit of a resonance coil and a condenser is provided in association with a superconducting ring having one Joffson junction, and a high frequency current is applied to cause resonance. A so-called AC SQUID element configured to obtain a voltage corresponding to the external detection magnetic field from the circuit may be used.

The processing circuit 66 includes a memory 67. The subject 15 is stimulated, whereby
Uses the index finger 8 to move the operating member 26 upward to perform an operation. As a result, each time stimulation is performed, the SQUID element 61 obtains the signal shown in FIG. 13A for each stimulation. The subject 15 operates the operation member 26, whereby the light receiving element 13 is operated as shown in FIG.
As shown in, the electric signal output is obtained at each of the times t1 and t2. In the memory 67, each SQUID element 6
The output with the passage of time of 1 is always stored, and in particular, at times t1 and t when the signal output from the light receiving element 13 is obtained.
The waveforms in each of the equal periods T10 and T20 over 2 and 1 are stored in the memory 67 as digital values as described above. The processing circuit 66 adds and averages the waveforms over the time T10 and T20 obtained in FIG. 13 (1) over a plurality of times, for example, about 100 times, thereby eliminating an error due to noise, and thus each SQUID element 6
It is possible to accurately obtain each cerebral magnetic field.

[0028]

As described above, according to the present invention, the operation means made of a material that does not electromagnetically affect the biological signal is provided in the magnetically shielded room in which the biological signal measuring device is installed. A pair of optical fibers are provided so that the optical path is blocked by the operation member of the means or the light is guided through the optical path, and the optical fibers are connected to the light emitting element and the light receiving element outside the magnetically shielded chamber, respectively. Since the light emitting element and the light receiving element can prevent the biological signal from being adversely affected, it is possible to improve the SN ratio of the biological signal. It is important that this signal-to-noise ratio is good when it has a low frequency component at and the signal is weak.

According to the present invention, the operation member is operated by a finger such as the index finger of the subject, and the operation amount thereof may be a very small displacement amount so as to block the light of the optical fiber. And the electrical relationship between the electric signal output obtained from the light-receiving element and the time relationship are accurately matched, whereby the measured biological signal temporally corresponding to the electrical signal output of the light-receiving element can be accurately obtained. Like

Further, according to the present invention, the operation means main body is placed with the vicinity of the tip of the index finger placed on the upper part of the operation member.
Since it has a width that can be gently covered with the hand and has a length that can be placed around at least the wrist, it is possible to operate the operation member in a very natural state of the subject. Also by this, the excellent effect that the temporal relationship between the motion and the signal output obtained from the light receiving element can be accurately associated can be achieved.

Further, according to the present invention, since the holding member to which one end of the pair of optical fibers is fixed is housed in the housing recess of the support of the operation means main body, the pair of optical fibers is stored. For example, the fibers can be guided and guided in a parallel state, so that the optical fiber is prevented from being caught by the subject and an operator, or by an obstacle, and a smooth measurement work is performed. be able to.

Further, according to the present invention, the distribution of the weak brain magnetic field can be measured by the brain magnetic field measuring assembly provided in the magnetically shielded room, and the light is received by the memory in response to the output of the light receiving element. Or, the output of the superconducting quantum interference magnetometer before and after the time of interruption is stored, and the outputs of multiple times with the passage of time are added and averaged for each magnetometer, and the accurate brain magnetic field for each magnetometer is stored. Can be measured.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a usage state of an operating unit 1 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a simplified overall configuration of a brain magnetic field measurement apparatus 14 including an operating means 1.

FIG. 3 is a perspective view showing a state where a brain magnetic field is measured by a brain magnetic field measuring device 14.

FIG. 4 is a plan view of the operating means 1.

5 is a side view of the operating means 1. FIG.

FIG. 6 is a sectional view taken along section line VI-VI in FIG. 4;

7 is a cross-sectional view taken along the section line VII-VII in FIG.

FIG. 8 is a plan view of a holding member 28.

9 is a side view of a holding member 28. FIG.

FIG. 10 is a front view of a holding member 28.

FIG. 11 is a diagram showing a simplified principle of the embodiment of the present invention shown in FIGS.

FIG. 12 is a vertical cross-sectional view showing a simplified configuration of part of the brain magnetic field measurement assembly 18.

FIG. 13 is a waveform diagram for explaining the operation of the brain magnetic field measurement apparatus 14.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Operating device for measuring brain magnetic field 3 Magnetically shielded room 4 Hands 5 Operating means 8 Index finger 9,10 Optical fiber 11 Optical path 12 Light emitting element 13 Light receiving element 14 Brain magnetic field measuring device 16 Bed 17 Head 18 Magnetic field measuring assembly 25 Operating means main body 26 operation member 27 support member 28 holding member 29 base body 30 lid 31 storage recess 44 operation piece 45 flange 46 light shielding piece 58 superconducting quantum interference magnetometer 59 detection coil 67 memory

Claims (5)

[Claims] 1. (a) An operating means which is provided in the vicinity of a biological signal measuring device for measuring a biological signal and which is made of a material that does not electromagnetically adversely affect the biological signal to be measured. (B) an operation means having an operation means main body to be formed and an operation member made of a material that shields light, which is relatively displaced with respect to the main body and removably enters into the light passage to interrupt the light passage; A pair of optical fibers, one end of each of which is arranged on both sides of the operation member of the optical path, and the other end of which is provided separately from the biomagnetism measuring device, and (c) light is applied to the other end of the one optical fiber. An operating device for measuring a biological signal, comprising: a light emitting element for guiding; and (d) a light receiving element for receiving light from the other end of the other optical fiber. 2. The operation means main body has a width that can be gently covered with a hand with the vicinity of the tip of a finger placed on the upper portion of the operation member, and has a length on which at least the vicinity of the wrist is placed. The operating device for measuring a biological signal according to claim 1, wherein the operating device has a substantially elongated shape. 3. The operating means main body has a substantially rectangular parallelepiped outer shape, a support body having a storage recess formed at the distal end in the longitudinal direction, and an operating member housed in the storage recess, and the operating member is vertically displaceable. The pair of optical fibers are fixed to each other along the longitudinal direction of the support body, and each of the one ends has a holding member facing each other on both sides of the operating member. Item 2. An operating device for measuring a biological signal according to item 1 or 2. 4. (a) a magnetically shielded room, (b) a brain magnetic field measurement assembly provided in the magnetically shielded room, wherein (b1) a cryogenic container covering at least the skull, and (b2) a cryogenic container in the cryogenic container. A plurality of superconducting quantum interference magnetometers provided, which are distributed and arranged outside the skull, and each have a brain magnetic field detecting coil for detecting a weak magnetic field from the brain. A brain magnetic field measurement assembly provided; and (c) an operating means which is provided in the shielded room and is made of a material that does not electromagnetically affect the detection of the brain magnetic field.
(C1) made of an operation means main body forming an optical path, and (c2) made of a material for shielding light, and relatively displaced with respect to the main body,
An operating means having an operating member that releasably enters the optical path and blocks the optical path, and (d) one end portion is arranged on both sides of the operating member of the optical path and the other end portion of the magnetic shield chamber is provided. A pair of optical fibers extending outwardly; (e) a light emitting element for guiding light to the other end of one optical fiber; (f) receiving light from the other end of the other optical fiber A light-receiving element, (g) a memory for storing the output of the magnetometer, and (h) a memory for storing the output of the magnetometer before and after light is received or blocked in response to the output of the light-receiving element. An apparatus for measuring a brain magnetic field, comprising: 5. The cerebral magnetic field measurement apparatus according to claim 4, further comprising means for averaging the outputs of a plurality of times stored in the memory for each magnetometer, the outputs being output a plurality of times.