JP3751514B2 - Brain machine diagram sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brain machine diagram sensor for measuring micro deformation and micro vibration of a scalp accompanying a brain activity of a living body.
[0002]
[Prior art]
In addition to reflections on external stimuli such as sleep, light, and sound, brain activity includes brain activities such as advanced emotions and emotions such as past sad memories and imagination of a desire for success in the future. Research on the brain is currently preceded in Europe and the United States, and was started as strategic research in Japan in the 1990s. Research that comprehensively elucidates brain functions is also an important issue in brain research, and various measurement methods are used.
[0003]
An electroencephalograph has been used for many years for comprehensive measurement of this brain function. The electroencephalograph has been developed since the discovery of the electrocardiogram of Berger in Germany in 1929, and has been the most popular instrument for many years, but this is done by attaching electrodes to the scalp and fixing it. The accompanying microvolt level minute voltage is detected.
[0004]
There are two types of electrode attachment methods: a unipolar derivation method using the earlobe or the like as a reference potential, and a bipolar derivation method in which a pair of electrodes are placed close together. The types of brain waves are: resting alpha waves (approximately 10 Hz), awakening / exciting beta waves (17-30 Hz), delta waves (1 to 2 Hz irregular waves) during brain diseases such as consciousness disorder, and θ waves (4 to 8 Hz) is known. Research on sleep electroencephalograms is also widely conducted, and early sleep electroencephalogram (group wave of 13 to 15 Hz), brain wave during sleep (δ wave of 0.5 to 3 Hz) and the like are known.
[0005]
In addition, evoked potentials due to external stimuli appear in a place peculiar to perceptual stimuli, appear in the visual area of the back of the head for visual stimuli, and appear in the auditory area of the temporal region for auditory stimuli. As the pathologic brain waves, epileptic large seizure waves, wave-and-spike waves, trapezoidal waves, and the like are known. The origin of EEG is unknown, but it is thought to be strongly related to visual perception.
[0006]
In contrast, magnetoencephalography has been widely studied recently. This detects a magnetic field associated with brain activity with a superconducting magnetic field sensor (superconducting quantum interference device; SQUID). This cerebral magnetic field is detected as an extremely weak magnetic field of picotesla (pT, 10 nG) near the skin surface of the head, but since it is one hundred million of the magnitude of geomagnetism, it is in a strict magnetic shield room. Measured with a large and expensive superconducting device while realizing an absolute temperature of 4K with liquid helium.
[0007]
Both the electroencephalogram (electroencephalogram) and the magnetoencephalogram (magnetoencephalogram) are electromagnetic quantities associated with brain activity and are considered to have the same origin. Therefore, there are many common points in biological information and medical information obtained from these. In the magnetoencephalogram, it has been reported that the induction site can be measured in more detail, but research has just started. The measurement technique is easier to measure the electroencephalogram.
[0008]
On the other hand, it was reported by Inaga in 1966 that fine vibrations on the skin surface were correlated with EEG [Kazutoshi Inaga: “Microvibration and EEG”, Psychiatry, 8 (3), 22-27 (1966)]. In 1993, the Institute of Biotechnology, Japan reported that microvibrations were detected on the skin surface of the head due to brain activity [Kenro Doko: “Fluctuations in frequency and arousal levels of microvibrations on biological surfaces” ”, Ergonomics, vol. 30, no. 3,165-170 (1994)]. It was reported that when the acceleration sensor using a piezoelectric element was attached to the temple of the subject, a periodic amplitude modulation wave-like vibration of about 7 Hz appeared at rest, and vibrations of various frequencies of 5 to 15 Hz appeared during arousal excitement. is there. However, these microvibration signals are difficult to distinguish from noise, and it is not easy to discriminate clear brain functions.
[0009]
Unlike the electroencephalogram or magnetoencephalogram, this signal is not an electromagnetism but a mechanical quantity (mechanical quantity), so it is considered as information complementary to the electroencephalogram for brain function measurement and brain disease diagnosis. This relationship corresponds to the relationship between an electrocardiogram, a magnetocardiogram and a cardiac device diagram (pulsation diagram, heart sound diagram, arterial pulse wave diagram) in cardiac function measurement of the circulatory system, and is a relationship that improves the accuracy of disease diagnosis.
[0010]
This head skin vibration measurement is a mechanical quantity signal different from the electroencephalogram or magnetoencephalogram electromagnetic signal, and is considered to give important information for diagnosis of brain diseases. Therefore, it is necessary to develop a more clear measurement method for skin movement.
[0011]
[Problems to be solved by the invention]
In view of the above situation, the present invention provides a highly sensitive acceleration sensor (Japanese Patent Application No. 11-366602) using an amorphous magnetostrictive wire stress impedance effect element (Japanese Patent Application Laid-Open No. Hei 10-170355) already proposed by the present inventor. An object of the present invention is to provide a portable electroencephalographic sensor that is micro-sized and easily fixed to the skin of the head, and detects vibration and larger skin displacement accompanying brain activity.
[0012]
Here, it seems that the term “brain machine diagram” (mechanoencephlogogram) does not yet exist. This is because the inventors of the present invention have studied the heart cardiogram so far. This is a convenient term that suggests the relationship between the contrast of the brain and the electroencephalogram, and means a time series of mechanical motion (vibration) associated with brain activity.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention achieves the above object. [1] In a brain machine sensor, a fixed piece, a glass substrate fixed to the fixed piece, and a linear groove formed on the glass substrate are attached and mounted. An acceleration sensor having an inertial mass fixed to the tip of the glass substrate, fixing the fixed piece to the skin of the human head, and causing a current to cause a skin effect on the magnetic material The time series information accompanying the brain activity is detected by changing the impedance of the magnetic material with respect to stress in a state where current is applied.
[0014]
[2] In the brain diagram sensor described in [1], the current that causes the skin effect is an alternating current or a pulsed current.
[0015]
[3] In the brain diagram sensor described in [1] or [2] above, the acceleration sensor is an acceleration sensor using a stress impedance effect of an amorphous magnetic material.
[0016]
[4] The brain diagram sensor described in [3], wherein the amorphous magnetic body is a negative magnetostrictive amorphous wire.
[0017]
[5] The brain diagram sensor according to [4], wherein the negative magnetostrictive amorphous wire has a diameter of 30 μm or less.
[0018]
[6] The brain diagram sensor according to [4] or [5], wherein the amorphous wire is arranged on one side of a substrate.
[0019]
[7] The brain diagram sensor described in [4] or [5] above, wherein the amorphous wires are arranged on both surfaces of the substrate so that opposite stresses are applied to the amorphous wires. you.
[0020]
Amorphous magnetostrictive wire (CoSiB) is a tough elastic body having a diameter of 20 μm and a material having excellent corrosion resistance, and is therefore suitable for detecting stress and strain. A pulse-energized sensor electronic circuit using a CMOS inverter multi-vibrator has already been developed to generate a stress impedance effect (SI effect) in this sensor head to generate an ultrasensitive stress detection characteristic with a strain gauge factor of about 4000. Therefore, it was possible to realize an easy-to-carry brain sensor using a micro-acceleration sensor with high sensitivity, high-speed response, and low power consumption.
[0021]
The brain machine diagram complements the electroencephalogram and is effective in diagnosing brain diseases such as hemorrhoids and brain tumors, as well as mental tension and emotional excitement such as sad memories of the past and desire for a bright future. Reflecting mental states such as dynamism and relaxation (sleepiness), various applications such as a lie detector, a traffic accident prevention system by detecting drowsiness of car driving, and psychotherapy can be considered.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0023]
FIG. 1 is a schematic view of a head of an SI effect acceleration type sensor according to the first embodiment of the present invention, FIG. 2 is a circuit diagram of the SI effect acceleration type sensor, and FIG. It is a schematic diagram which shows the attachment state of.
[0024]
As shown in these figures, 1 is a fixed piece, 2 is a glass substrate having a thickness of 0.1 mm, a width of 3 mm, and a length of 8 mm fixed to the fixed piece 1. The glass substrate 2 has a width of about 100 μm. A linear groove 3 having a length of 5 mm was formed with a diamond cutter, and a CoSiB amorphous negative magnetostrictive wire 4 having a diameter of 20 μm and a length of 4 mm was buried in the linear groove 3 and adhered by a ceramic bond 5. The inertia mass 6 of 0.1 gram was fixed to the tip of the glass substrate 2, and the fixing piece 1 at the other end was adhered to the head skin of the subject A with the double-sided tape 7. The total weight of the head is 0.3 grams. Reference numeral 10 denotes an SI effect acceleration type sensor.
[0025]
As shown in FIG. 2, the circuit of the acceleration sensor 10 incorporating the sensor head is configured as follows.
[0026]
A multivibrator oscillation circuit 11 is configured by _two inverters Q ₁ and Q ₂ , a resistor R, and a capacitor C using an IC chip incorporating six CMOS inverters. The output voltage is converted into a pulse voltage by a differentiation circuit 12 comprising a resistor R _D and a capacitor C _D , shaped and amplified by an inverter Q ₃ (13), and energized to an amorphous wire (SI element) 14 to generate an SI effect. Let
[0027]
The induced pulse voltage of the amorphous wire 14 is a pulse height modulation (PHM) circuit because its height changes depending on the stress applied to the wire. This pulse voltage is converted into a DC voltage through a peak hold circuit 15 comprising a resistor R _H and a capacitor C _H through a Schottky barrier diode SBD, and converted into an output voltage of the acceleration sensor 10 by a zero adjustment differential amplifier 16.
[0028]
FIG. 4 shows a 23-year-old healthy man resting with his head fixed to an easy chair, and the sensor head of FIG. 1 was pasted between the eyebrows as shown in FIG. 3 to measure skin displacement and vibration associated with brain activity. It is a result. Although not shown, the sensor head can be provided with a portion having a circuit connected by a wire, for example, on the ear of the subject.
[0029]
FIG. 4A shows a closed and resting state in which an arch-shaped waveform of about 0.2 Hz is superimposed on a minute vibration of about 5 Hz. The change width is about 5 mG (Gal). The former is a microvibration, and the latter is a waveform detected for the first time this time. This slow waveform is not detected by a conventional acceleration sensor, and it is thought that the sensor head is inclined due to skin deformation. This resting waveform also appeared in the case of several subjects.
[0030]
FIG. 4 (b) shows a case where mental arithmetic (division) is performed while resting with closed eyelids, and a large dynamic change appears in several places within 20 seconds. The eye muscle may be tense and the eyeball may have moved during mental arithmetic.
[0031]
FIG. 4C shows a case where a nap state is entered after resting, and only a minute vibration of about 5 Hz is kept flat.
[0032]
FIG. 5 is a measurement result of a brain machine diagram of a 34-year-old woman. Closed and rested in an easy chair.
[0033]
FIG. 5A shows a resting state where a wave of about 0.3 Hz appears. FIG. 5 (b) is a case of remembering a past sad event, and a large mountain of about 2 Gal appeared, and it jumped and decreased in a staircase pattern. Many small pulsed waveforms also appeared. It seems that the eye muscles are tense with sad memories and the skin between the eyebrows also moves.
[0034]
FIG. 5 (c) is a case where a bright and pleasant future is envisioned, and a wave of about 0.3 Hz appears dynamically at rest. The imagination and rest of the bright future are considered common emotions.
[0035]
FIG. 5D shows a case in which a feeling of frustration in performing a given work by the due date is felt, and it is considered that the eye muscles are tense due to a positive tension.
[0036]
The waveforms in FIGS. 5A to 5D include micro vibrations, but are difficult to discriminate because they are very small.
[0037]
These measured waveforms are in a closed comfort state and have the same appearance, but clearly show the brain activity state, and the high-sensitivity sensor based on the SI effect of the present invention uses microvibration (5 to 15 Hz). ) Is detected as acceleration, and a large slow waveform of 1 Hz or less is detected by tilting the sensor head as the skin deforms, and the SI effect changes. I understood that I could do it.
[0038]
For this reason, this sensor is called an acceleration sensor instead of an acceleration sensor.
[0039]
In addition, when the subject was instructed to blink by opening, a dynamic pulse-like waveform appeared. Therefore, it is considered that the eyeball control muscle is involved in the cause of the brain machine diagram. As shown in FIG. 4B, during the mental calculation, the subject imagined the number of the division calculation in the closed state and seemed to strain the eye muscle.
[0040]
FIG. 6 is a schematic view of a head of an SI effect acceleration type sensor according to a second embodiment of the present invention, and FIG. 7 is a circuit diagram of the SI effect acceleration type sensor.
[0041]
FIG. 6 is a circuit diagram of a sensor head having a structure in which amorphous magnetostrictive wires 8 and 9 each having a diameter of 20 μm and a length of 5 mm are bonded to both surfaces of the glass substrate 2 of the acceleration type sensor head shown in FIG. The amorphous magnetostrictive wires 8 and 9 have an ultrafine diameter of 30 μm or less, and can constitute a sensor that can be easily worn on the human head.
[0042]
FIG. 7 is an acceleration sensor circuit diagram for making the two amorphous wire SI elements shown in FIG. 6 differential. A pulse current from the CMOS multivibrator circuit shown in FIG. 2 is simultaneously applied to the two amorphous wires.
[0043]
When the substrate 2 of the sensor head is bent by the stress, opposite stresses are applied to the two wires 8 and 9, so that the increase and decrease in the induced pulse voltage of the two wires 8 and 9 are also opposite to each other. Therefore, when the peak hold voltage of the induced pulse voltage of the two wires 8 and 9 is input to the differential amplifier 20, the output voltage of the acceleration sensor becomes twice the sensitivity of the circuit shown in FIG.
[0044]
Further, according to this embodiment, because of the parallel circuit configuration, the common mode noise mixed from the power supply line is canceled out, so that more stable circuit operation can be performed.
[0045]
FIG. 8 is a result of measuring the brain machine diagram in an open state by attaching the acceleration sensor shown in FIG. 6 to the eyebrows of a 24-year-old healthy man as shown in FIG. 3, and FIG. In a resting state, the eyeball is stationary and distantly seen with the eyeball still. FIG. 8B shows a case where the line of sight is quickly moved to many places on the assumption of driving in an urban area, and a large stepped waveform appears, and acceleration due to movement of the eye muscles and eyeballs is measured. It is thought.
[0046]
In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, the microhead is easily fixed to the skin of the head, and the waveform that appears by deforming the skin due to minute vibrations and emotions accompanying brain activity is detected. A rich brain machine diagram sensor can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic enlarged view of a head of an SI effect acceleration type sensor showing a first embodiment of the present invention.
FIG. 2 is a circuit diagram of an SI effect acceleration sensor showing a first embodiment of the invention.
FIG. 3 is a schematic diagram showing a state in which the head of the SI effect acceleration type sensor according to the first embodiment of the present invention is attached to a subject.
FIG. 4 is a diagram showing the result of measuring the acceleration associated with brain activity measured by attaching the SI effect acceleration sensor according to the first embodiment of the present invention to the eyebrows of a 23-year-old healthy man and measuring the brain machine diagram.
FIG. 5 is a diagram showing measurement results of a brain machine diagram in which the SI effect acceleration type sensor according to the first embodiment of the present invention is attached to the eyebrows of a 34-year-old woman.
FIG. 6 is a schematic enlarged view of a head of an SI effect acceleration type sensor showing a second embodiment of the present invention.
FIG. 7 is a circuit diagram of an SI effect acceleration type sensor according to a second embodiment of the present invention.
FIG. 8 is a view showing a result of measuring a brain machine diagram in an open state by attaching an SI effect acceleration sensor according to a second embodiment of the present invention between eyebrows of a 24-year-old healthy man.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed piece 2 Glass substrate 3 Linear groove 4 CoSiB amorphous negative magnetostrictive wire 5 Ceramic bond 6 Inertial mass 7 Double-sided tape 8,9 Amorphous magnetostrictive wire 10 Accelerometer sensor 11 Multivibrator oscillation circuit 12 Differentiation circuit 13 Inverter Q ₃
14 Amorphous wire (SI element)
15 Peak hold circuit 16 Zero adjustment differential amplifier 20 Differential amplifier A Subject

Claims (7)

(A) a fixed piece;
(B) a glass substrate fixed to the fixing piece;
(C) a magnetic body that is bonded and mounted in a linear groove formed on the glass substrate;
(D) preparing an acceleration sensor having an inertial mass fixed to the tip of the glass substrate;
(E) When the fixed piece is fixed to the skin of the human head, and the impedance of the magnetic material is changed with respect to stress in a state in which a current that causes the skin effect is applied to the magnetic material , accompanying brain activity A brain diagram sensor characterized by detecting sequence information.   The brain machine diagram sensor according to claim 1, wherein the current that causes the skin effect is an alternating current or a pulse current.   3. The brain machine diagram sensor according to claim 1, wherein the acceleration sensor is an acceleration sensor using a stress impedance effect of an amorphous magnetic material.   4. The brain machine diagram sensor according to claim 3, wherein the amorphous magnetic body is a negative magnetostrictive amorphous wire.   5. The brain machine diagram sensor according to claim 4, wherein the negative magnetostrictive amorphous wire has a diameter of 30 microns or less.   The brain machine diagram sensor according to claim 4 or 5, wherein the amorphous wire is arranged on one side of a substrate.   The brain machine diagram sensor according to claim 4 or 5, wherein the amorphous wires are respectively arranged on both surfaces of a substrate so that opposite stresses are applied to the amorphous wires.

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