JP3584286B2 - Brain activity measurement system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a brain activity measurement system, and more particularly, to a brain activity measurement system that can maintain and promote the motivation and concentration of a subject during brain activity measurement.
[0002]
[Prior art]
FIG. 12 is a configuration diagram showing an example of a conventional brain magnetic field measurement system.
The brain magnetic field measurement system 500 includes a bed 30 on which a subject P is placed, a finger operating device 51 for sensing the movement of a finger F of the subject P, a dewar 32 containing a magnetic sensor (not shown), A couch 30, a finger room 51, and a shield room 33 accommodating the dewar 32 in a magnetically shielded space; an arithmetic unit 34 for calculating a brain magnetic field based on a magnetic signal obtained by the magnetic sensor; A control computer 35 for displaying the brain magnetic field and controlling each unit is provided.
[0003]
In general, when measuring the magnetic field associated with the electrical activity of the cranial nerve when the subject P intentionally moves the finger F, the subject P moves the finger F at regular intervals because the magnetic field is extremely weak. A method of increasing the SNR (Signal to Noise Ratio) by averaging the magnetic signals obtained in synchronization with the movement is adopted. For example, the subject P repeats moving the finger F 200 times for every mental count (counting in the heart) for 5 seconds.
[0004]
[Problems to be solved by the invention]
If the subject repeats his or her finger movements many times during mental counting, the monotony can gradually reduce motivation and concentration, resulting in boredom and drowsiness, which may interfere with measurement. There is a problem.
Accordingly, it is an object of the present invention to provide a brain activity measurement system that can maintain and promote the motivation and concentration of a subject during brain activity measurement.
[0005]
[Means for Solving the Problems]
In a first aspect, the present invention is a brain activity measurement system that measures activity in the brain when a subject consciously moves a part of the body, and provides the subject with a timing to move the part of the body. A sensory stimulus unit for providing a visual stimulus, an auditory stimulus, or a tactile stimulus to the subject for notifying, and a motion evaluation unit for feeding back the subject based on the actual motion of the subject and the evaluation based on the timing lag. A brain activity measurement system is provided.
In the brain activity measurement system according to the first aspect, the subject can recognize the timing at which a part of the body should be moved based on a change in a visual stimulus, an auditory stimulus, or a tactile stimulus. Since the feedback is provided, the measurement can be repeated as if it were a game. Therefore, it is possible to prevent boredom and drowsiness, and to maintain and promote the motivation and concentration of the subject.
[0006]
In a second aspect, the present invention provides a brain activity measurement system having the above configuration, further comprising progress status notification means for notifying a subject of the progress of the measurement. .
In the brain activity measurement system according to the second aspect, the subject can know the progress of the measurement, so that the measurement can be repeated more like a game. Therefore, it is possible to prevent boredom and drowsiness, and to maintain and promote the motivation and concentration of the subject.
[0007]
In a third aspect, the present invention provides the brain activity measurement system having the above configuration, wherein the sensory stimulus unit is a moving image display unit that displays a closed figure that is gradually filled so as to complete the fill at the timing. The present invention provides a brain activity measurement system characterized by the following.
In the brain activity measurement system according to the third aspect, since a closed figure that is gradually filled is displayed, it is complex enough to prevent boring and drowsiness and simple enough not to evoke advanced thinking. It can maintain and promote the motivation and concentration of the subject with a good balance. In addition, since the subject can take the timing without moving the eyeball, it is not necessary to generate noise due to the movement of the eyeball.
[0008]
According to a fourth aspect, the present invention provides the brain activity measurement system having the above-mentioned configuration, wherein the moving image display means includes a screen of a non-magnetic material installed in a shield room where the subject enters, and a screen outside the shield room where the subject enters. And a projector installed on the screen and projecting a moving image on the screen.
In the brain activity measurement system according to the fourth aspect described above, since the screen is placed close to the subject, the subject can view the display without moving the eyeball, and does not need to generate noise due to the movement of the eyeball. Also, since the screen is a non-magnetic material, it does not hinder the measurement of the magnetic signal. Further, since the projector is provided outside the shielded room, noise generated by the projector does not disturb the measurement.
[0009]
In a fifth aspect, the present invention provides the brain activity measurement system having the above-mentioned configuration, wherein the movement evaluating means feeds back a higher score to the subject as the difference between the two is smaller when the actual movement of the subject is earlier than the timing. If the actual movement of the subject is later than the above timing, the brain activity measurement system is provided as a score evaluation unit that feeds back at least one of a zero point and a penalty according to the delay to the subject.
In the brain activity measurement system according to the fifth aspect, if the subject moves a part of the body without delay from the timing, the score is shown to the subject each time, so that the measurement can be repeated just like a game. I can do it. Therefore, it is possible to prevent boredom and drowsiness, and to maintain and promote the motivation and concentration of the subject. If the actual movement of the subject coincides with the timing, the highest score is obtained. If the actual movement is slightly later, the score becomes 0 or a penalty according to the delay is imposed. Recognized by the subject, the sense of the game can be further increased.
[0010]
In a sixth aspect, the present invention provides the brain activity measurement system having the above configuration, wherein the score evaluation means displays the score at a position where the closed figure and the score can be simultaneously viewed without moving an eyeball. The present invention provides a brain activity measurement system characterized by the following. In the brain activity measurement system according to the sixth aspect, the subject can see the score without moving the eyeball, and does not need to generate noise due to the movement of the eyeball.
[0011]
According to a seventh aspect of the present invention, in the brain activity measurement system having the above-described configuration, the progress status notification means is provided at a position where the closed figure, the number of times of execution of the measurement, and the remaining number of times can be simultaneously viewed without moving the eyeball. A brain activity measurement system is provided, which is a measurement count display means for displaying the number of times of execution of the measurement and the remaining number of times.
In the brain activity measurement system according to the seventh aspect, the subject can see the number of times of measurement and the remaining number of times without moving the eyeball, and it is not necessary to generate noise due to eyeball movement.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited to this.
[0013]
FIG. 1 is a configuration diagram showing a brain magnetic field measurement system according to an embodiment of the present invention.
The brain magnetic field measurement system 100 includes a bed 30 on which the subject P is placed in a lying posture, a finger operation device 1 for sensing the movement of the finger F of the subject P, and a magnetic sensor (not shown) of, for example, 160 channels. , A computing device 34 for calculating a cerebral magnetic field based on a magnetic signal obtained by the magnetic sensor, and a control computer 35 for displaying the cerebral magnetic field and controlling each unit. Become.
[0014]
Also, the optical device 2 that outputs a trigger signal S at the moment when the finger operation device 1 detects the movement of the finger F, a moving image (FIGS. 5 to 7) indicating the timing at which the finger F should be moved, and feedback information ( A notebook computer 4 that generates image data, a projector 5 that emits image light, a mirror 6 that reflects the image light, and an image that is displayed by the light reflected by the mirror 6. And a screen 7.
[0015]
Further, there is provided a shield room 33a in which a hole through which the image light passes is formed, and which accommodates each part (the bed 30, the finger operating device 1, the dewar 32, the mirror 6, and the screen 7) in a magnetically shielded space. It becomes.
[0016]
FIG. 2 is a configuration diagram showing the finger operation device 1 and the optical device 2.
The finger operation device 1 includes an optical switch 13 in which an optical fiber 11 is embedded on a concave first wall side and an optical fiber 12 is embedded on a second wall side, and a base portion 14 on which the optical switch 13 is mounted. Is provided. The bottom surface of the optical switch 13 is attached to the upper surface of the base portion 14 with Velcro (registered trademark) so that the subject P can adjust the finger F to a position where the finger F can be easily moved. The material of the structure of the optical switch 13 is, for example, plastic. The material of the base portion 14 is, for example, polystyrene foam.
The optical device 2 includes a light emitting diode 21 for transmitting light to the optical fiber 11, a photodiode 22 for detecting light returned through the optical fiber 12, and a trigger signal S at a moment when the detection level exceeds a threshold level th. And a level adjuster 24 for adjusting the threshold level th.
[0017]
As shown in FIG. 3, a light exit hole Hout penetrating to the end of the optical fiber 11 is formed in the concave first wall of the optical switch 13. The second wall has a light incident hole Hin penetrating therethrough to the end of the optical fiber 12. As described above, by setting the ends of the optical fibers 11 and 12 at positions recessed from the holes, intrusion of light from the outside can be reduced and malfunction can be prevented.
As shown in FIG. 3A, when the finger F is placed in the concave valley, light is blocked by the finger F, so that light does not enter the optical fiber 12.
As shown in FIG. 3B, when the finger F is raised, the light passes through the valley portion, so that the light enters the optical fiber 12. At this moment, the detection level exceeds the threshold level th, and the optical device 2 outputs the trigger signal S. As described above, by detecting the moment when the finger F is raised, the detection error due to the stroke of the finger F and the misplacement of the position of the finger F are different from the case where the moment when the finger F is lowered is detected. Can be reduced.
[0018]
In addition, as the finger operation device 1, for example, a finger input device disclosed in JP-A-2000-316828 may be employed.
[0019]
FIG. 4 is a flowchart showing a process of measuring the brain magnetic field when the subject P repeatedly moves the finger F consciously by the brain magnetic field measurement system 100 of FIG.
In step U1, the measurer sets the number of times the finger F is moved, that is, the number of repetitions N, on the notebook computer 4. For example, N = 200.
In step U2, the measurer sets an interval at which the finger F is moved, that is, an operation interval T, on the notebook computer 4. For example, T = 5 [s].
In step U3, the measurer sets a display time τ of a moving image indicating the timing at which the finger F should be moved on the notebook computer 4. For example, τ = 3 [s].
[0020]
In step U4, the arithmetic unit 34 starts calculating a brain magnetic field based on the magnetic signal obtained by the magnetic sensor.
In step U5, the number of completed movements i indicating the number of executed movements is initialized to i = 0.
[0021]
In step U6, the elapsed time t is initialized to t = 0, and measurement of the elapsed time is started.
In step U7, the notebook computer 4 and the projector 5 display on the screen 7 "a moving image in which the inside of the circle is painted in a fan-shaped direction as the elapsed time t, and the entire inside of the circle is painted at the moment when the moving image display time τ elapses. Is displayed. That is, at time t = 0, only the circular contour is displayed as shown in FIG. At the time of t = a (0 <a ≦ τ), as shown in FIG. 6, the inside of the fan shape having the central angle α = a × 360 ° / τ is painted out. At the moment t = τ, the entire circle is painted out as shown in FIG. The fill color is arbitrary, but is, for example, dark blue. In addition, from the viewpoint of presenting a moving image without a sense of incongruity to the subject P, it is preferable to continuously change the painted area. However, if the image is changed in steps of about 0.1 s or less, it is empirically unnecessary to give the subject P an unnatural impression (in the above numerical example, α per 0.1 s is changed stepwise by 12 °). It is enough if you change it to
The subject P moves (raises) the finger F in anticipation of the moment when the entire circle is painted. From the viewpoint of improving the magnetic field measurement accuracy, it is preferable that the subject P keeps looking at the center of the circle to minimize body movements (eye movement, blinking, etc.) of about 1 s before and after t = τ.
[0022]
In step U8, the display in step U7 is continued until t = τ, and when t = τ, the process proceeds to step U9.
[0023]
In step U9, the process waits until a predetermined waiting time (for example, 1 s) elapses, and after that, the process proceeds to step U10.
In step U10, the notebook computer 4 measures a difference between the elapsed time t = b (output time of the trigger signal S) when the finger F is moved and t = τ, and calculates a score reflecting the difference. . For example, when 0 ≦ b ≦ τ−1 or b> τ, the score is “0”, when b = τ, the score is “100”, and during the period of τ−1 <b <τ, the score is 100. − (Τ−b) × 100. As an example of the score, the score in the case of moving the finger F too early by 0.2 [s] and b = 2.8 [s] is "80". When b> τ, a penalty corresponding to the delay (= b−τ) may be fed back to the subject P instead of or in addition to setting the score to “0”.
[0024]
In step U11, i is incremented by one.
In step U12, the remaining number = Ni is calculated.
[0025]
In step U13, as shown in FIG. 8, the notebook computer 4 and the projector 5 display the current score (the score calculated in step U10), the highest score to date, Displays the number of completed and remaining times.
[0026]
In step U14, the display in step U13 is continued until t = T, and when t = T, the process proceeds to step U15.
In step U15, if the number of remaining times is not 0, the process returns to step U6. If the number of remaining times is 0, the process proceeds to step U16.
[0027]
In step U16, the control computer 24 adds and averages the magnetic signals for each operation time interval T, and displays the result in, for example, a graph or an isomagnetic field diagram.
[0028]
(Example 1)
For subjects unfamiliar with brain magnetic field measurement, the extension motion of the index finger of the left hand was performed 200 times at 5 s intervals. At this time, a moving image (see FIGS. 5 to 7) in which N = 200 and T = 5 [s] was displayed. Then, a θ-wave component (a brain wave component of 4 to 7 Hz) was measured using a 160-channel whole-head type brain magnetic field measurement system.
The straight line a in FIG. 9 is a straight line approximating the measurement result.
(Comparative Example 1)
The θ wave component was measured under the same conditions as in Example 1, but with a mental count.
The straight line b in FIG. 9 is a straight line approximating the measurement result.
In Example 1, the increase rate of the θ-wave component is lower than in Comparative Example 1. It is known that the θ wave component increases when a person shifts to a light sleep state. Therefore, it can be seen that the present invention does not cause sleepiness.
[0029]
(Example 2)
A subject who had experienced 10 or more brain magnetic field measurements in the past and had become accustomed to mental counting was subjected to stretching motion of the index finger of the left hand 200 times at 5 s intervals. At this time, a moving image (see FIGS. 5 to 7) in which N = 200 and T = 5 [s] was displayed. Then, a θ-wave component (a brain wave component of 4 to 7 Hz) was measured using a 160-channel whole-head type brain magnetic field measurement system.
The straight line a in FIG. 10 is a straight line approximating the measurement result.
(Comparative Example 2)
The θ wave component was measured under the same conditions as in Example 2, but with a mental count.
A straight line b in FIG. 10 is a straight line approximating the measurement result.
In Example 2, the increase rate of the θ-wave component is lower than in Comparative Example 2. It is known that the θ wave component increases when a person shifts to a light sleep state. Therefore, it can be seen that the present invention does not cause sleepiness.
[0030]
According to the above-described brain magnetic field measurement system 100, a moving image (see FIGS. 5 to 7) indicating the timing at which the finger F should be moved is displayed on the screen 7, so that an appropriate visual stimulus is periodically given to the subject P. Therefore, the consciousness level of the subject P can be increased to a stable state. In addition, by feeding back the deviation of the timing of moving the finger F and the progress of the measurement to the subject P (see FIG. 8), the operation can be provided with a game property, and the motivation and concentration can be maintained for a longer time. Become like
[0031]
-Other embodiments-
(1) As shown in FIG. 11, a brightness change area Rv in which the brightness changes periodically and a standard brightness area Rs of constant brightness are displayed side by side on the screen 7, and the brightness change area Rv is displayed. The subject may move a part of the body at the timing when the luminance becomes the luminance of the standard luminance region Rs. In this case, since the image itself does not move, there is an advantage that the eye movement of the subject can be further reduced.
[0032]
(2) A sound whose frequency changes periodically (e.g., a sound in the range of 10 Hz to 1 kHz) is output, and the subject moves a part of the body at a timing when the frequency reaches a predetermined frequency (e.g., at an instant of 1 kHz). You may do so. In this case, the present invention can be applied to a visually impaired person.
[0033]
(3) The subject may be provided with a tactile stimulus for perceiving the timing of moving a finger or the like. In this case, the present invention can be applied to a visually or hearing impaired person.
[0034]
【The invention's effect】
According to the activity measurement system in the brain of the present invention, the subject can recognize the timing at which a part of the body should be moved based on a change in a visual stimulus, an auditory stimulus, or a tactile stimulus, and a difference between the actual motion and the timing is fed back. Therefore, the measurement can be repeated like a game. Therefore, it is possible to prevent boredom and drowsiness, and to maintain and promote the motivation and concentration of the subject.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a brain magnetic field measurement system according to an embodiment of the present invention.
FIG. 2 is a configuration diagram showing a finger operation device and an optical device in the brain magnetic field measurement system of FIG. 1;
FIG. 3 is an explanatory diagram showing the principle of sensing the movement of a subject's finger with an optical switch.
FIG. 4 is a flowchart showing a brain magnetic field measurement process by the brain magnetic field measurement system of FIG. 1;
FIG. 5 is an explanatory diagram showing a moving image displayed by the brain magnetic field measurement system of FIG. 1;
FIG. 6 is another explanatory diagram showing a moving image displayed by the brain magnetic field measurement system in FIG. 1;
FIG. 7 is still another explanatory diagram showing a moving image displayed by the brain magnetic field measurement system in FIG. 1;
FIG. 8 is an explanatory diagram showing feedback information displayed by the brain magnetic field measurement system of FIG. 1;
FIG. 9 is a graph of Example 1 and Comparative Example 1.
FIG. 10 is a graph of Example 2 and Comparative Example 2.
FIG. 11 is an explanatory diagram showing another embodiment.
FIG. 12 is a configuration diagram showing an example of a conventional brain magnetic field measurement system.
[Explanation of symbols]
REFERENCE SIGNS LIST 100 Brain magnetic field measurement system 1 Finger operation device 2 Optical device 4 Laptop computer 5 Projector 6 Mirror 7 Screen 30 Sleeper 32 Dewar 33a Shield room 34 Operation device 35 Control computer F Finger P Subject S Trigger signal

Claims (7)

A brain activity measurement system that measures brain activity when a subject consciously moves a part of the body,
Sensory stimulus means for giving the subject a visual stimulus, an auditory stimulus, or a tactile stimulus for notifying the subject of the timing at which a part of the body should be moved, and a motion for feeding back the subject based on the actual motion of the subject and an evaluation based on the timing difference An activity measuring system in the brain, comprising: an evaluation unit. 3. The brain activity measurement system according to claim 2, further comprising progress status notification means for notifying the subject of the progress of the measurement. 3. The brain activity measurement system according to claim 1, wherein the sensory stimulus unit is a moving image display unit that displays a closed figure that is gradually filled so that the filling is completed at the timing. 4. Activity measurement system in the brain. 4. The brain activity measurement system according to claim 3, wherein the moving image display means includes a screen of a non-magnetic material installed in a shield room where a subject enters, and a moving image on the screen installed outside the shield room where the subject enters. A brain activity measurement system, comprising: a projector that projects an image. 5. The brain activity measurement system according to claim 1, wherein when the actual movement of the subject is earlier than the timing, a higher score is given to the subject as the difference between the two is smaller. And a score evaluation unit that feeds back to the subject at least one of a zero point and a penalty according to the delay when the actual movement of the subject is later than the timing. 6. The brain activity measurement system according to claim 5, wherein the score evaluation means displays the score at a position where the closed figure and the score can be viewed simultaneously without moving an eyeball. Measurement system. In the brain activity measurement system according to any one of claims 3 to 6, the progress state notification means is provided at a position where the closed figure, the number of executions of the measurement, and the remaining number of times can be simultaneously viewed without moving an eyeball. A brain activity measurement system, characterized in that it is a measurement frequency display means for displaying the number of times the measurement has been performed and the remaining number of times.

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