JPS5822218B2 - EEG analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electroencephalogram analyzer that cancels input information for only that period when a body movement occurs during electroencephalogram detection to obtain accurate data.

EEG is a spontaneous, rhythmic electrical phenomenon that is detected by attaching electrodes to predetermined locations on the surface of the brain cortex or scalp, and is generally detected by I.
The waves range in frequency from Hz to 30Hz.

These brain waves consist of δ1 waves (1-2Hz) and β2 waves (2Hz).
~4Hz), theta wave (4~8H2), alpha wave (8~12.5
Hz), β1 wave (12,5-20Hz) and β2 wave (
20-30Hz).

We investigated the appearance time and amplitude of each component, and further,
Power is calculated from the product of appearance time and amplitude, and this data plays an important role in medical research and clinical practice.

For example, it is possible to detect how many δ1 waves with an amplitude of 50μ or more appear in a unit sampling time (30 seconds or 60 seconds), and the proportion of this appearance time is 50% or more within the unit sampling time. When it becomes sleepy, it is determined that it is in a sleeping state,
The degree to which alpha waves with an amplitude of 20μ or more appear in a unit sampling time is detected, and when this appearance time is 50% or more of the unit sampling time, it is considered to be an awake state. to judge.

However, when detecting brain waves during sleep, the brain waves are disturbed by body movements such as turning over in bed, making it difficult to obtain accurate data.

In other words, when a body movement occurs, an unnatural output waveform with a large amplitude and a long period is produced, but when the data is automatically analyzed, there is a risk that it will be detected as a component of brain waves.

The present invention was made in view of the above points, and when a body movement occurs, the effective sampling time is set by subtracting the body movement occurrence time from the unit sampling time, and the biological information is also canceled when the body movement occurs. By doing so, accurate data can be obtained.

An embodiment of the present invention will be described below with reference to the drawings.

1 is a clock pulse generator that generates a reference clock pulse (for example, 1m5); 2 is a gate circuit; normally (when there is no body movement), it is opened by the output of inverter 3 and the clock pulse is sent to the next counter 4; send to.

5 is a body movement detector such as turning over in bed, and this body movement detector 5 is specifically an accelerometer attached to the body, a circuit for detecting high frequency components generated in brain waves when body movement occurs, or a body movement detector 5 attached to the shoulder. It consists of an electromyogram detector and other equipment.

When a signal is received from this body motion detector 5, the output from the inverter 3 disappears and the gate circuit 2 is closed.

A reset signal circuit 6 that outputs an output every unit sampling time is connected to the reset terminal of the counter 4.

A register 7 outputs the effective sampling time during the immediately preceding unit sampling time.

8 is a digital-to-analog conversion circuit (hereinafter referred to as DA circuit).

Next, 9 is an original waveform detection circuit for brain waves, and 10 is a cancellation circuit consisting of an analog switch, and the input signal is canceled by the body movement detector 5 when a body movement occurs.

11° to 116 are each component δ from the original waveform of the brain wave.
1 wave (1 to 2 Hz), δ2 wave (2 to 4 Hz), θ wave (4 to 8 Hz), α wave (8 to 12.5 Hz), β1 wave
waves (12,5-20 Hz), and β2 waves (20-30
This is a detection circuit for detecting Hz).

Specifically, these detection circuits 11° to 116 can be formed by a combination of filter circuits, but it is more effective to use the frequency analyzer of Japanese Patent Application No. 59739/1987, which was already proposed by the present applicant. be.

The basic principle is to sequentially measure the time between adjacent peaks of the brain waves to be analyzed, set a specific time window corresponding to the frequency component wave from each peak time, and calculate when the next peak occurs within that window. , determine the signal in that band,
At the same time as starting the next window, the amplitude of the determined signal and the time between the peaks are measured.

The circuit configuration consists of a peak position detection circuit that detects the positive peak position and negative peak position from the waveform to be analyzed, and a positive peak position that is connected to this peak position detection circuit and corresponds to the positive peak position and negative peak position. Two pulse shaping circuits are connected to these pulse shaping circuits to obtain a pulse train of A pulse train window setting circuit, a negative pulse train window setting circuit, a positive pulse train matching circuit and a negative pulse train matching circuit for obtaining a matching output between the outputs of these window setting circuits and the pulse train, and a waveform to be analyzed. Hold the positive peak value and negative peak value of , respectively, and calculate the difference from one held positive peak value to the next negative peak value and the difference from one negative peak value to the next positive peak value. a differential circuit that sequentially calculates the differences between the two and averages them, and a digital value that is connected to this differential circuit and the two matching circuits and is proportional to the output of the differential circuit with the matching outputs of these matching circuits as a reference. The device is equipped with an A/D converter circuit for determining the amplitude, and an amplitude register connected to the A/D converter circuit and storing the digital value as an amplitude.

Next, reference numerals 121 to 126 are gate circuits through which a clock pulse signal passes only during the time they are opened by the outputs of the electroencephalogram detection circuits 111 to 116.

13 to 136 are counters for these clock pulse signals, which are connected to the reset signal circuit 6 and reset every unit sampling time.

14. 146 are registers, and 151 to 156 are digital/analog conversion circuits (hereinafter referred to as DA circuits).

Reference numeral 16 denotes a switching circuit that sequentially outputs the outputs from the DA circuits 151 to 156.

Reference numeral 17 denotes an arithmetic circuit, specifically, the ratio of each of the DA circuits 151 to 156 on the time detection side of each component of the brain wave to the output of the DA circuit 8 on the unit sampling time setting side.
Calculate □□.

This arithmetic circuit 17 may perform arithmetic operations based on the outputs of the registers 7 and 14° to 146 when displaying analog values.

This arithmetic circuit 1T is specifically configured as shown in FIG.

That is, at the output end of the D-A circuit 8 on the unit sampling time setting side, there are resistors 18, 19, which are divided into points A (100%), B (50%), and C (20%), for example. 20 are connected to form a circuit for setting a predetermined percentage in stages, these points B and C are connected to a comparator 2L22,
And the output terminal of the switching circuit 16 is connected to these comparison circuits 21.
, 22.

These comparison circuits 21 and 22 are connected to the inverter 23
24.25, connected to terminals 28, 29, and 30 of the display 27 via the NAND circuit 26.

Then, an output is provided to a terminal 28 when the ratio is 50% or more, to a terminal 29 when the ratio is 20 to 50%, and to a terminal 30 when the ratio is 20% or less.

Next, the present invention will be explained in detail.

A 1 mS clock pulse signal is sent to the counter 4 via the gate circuit 2, and the number of pulses is counted every unit sampling time.

When a body movement occurs, the output from the body movement detector 5 is sent through the inverter 3, and the gate circuit 2 is closed only during that time.

Kara. Since a reset signal is sent to the counter 4 accurately every unit sampling time, pulses generated when the body moves are excluded from the counter 4.

Therefore, only the number of pulses corresponding to the effective sampling time obtained by subtracting the body movement time from the unit sampling time is stored in the register 7.

The force is DA converted and sent to the arithmetic circuit 17.

On the other hand, the original waveform of the brain wave is detected by the detection circuit 9, and the signal is sent to the cancellation circuit 10.

Here, when a body movement occurs, it is canceled and the brain waves only when no body movement occurs are sent to the next stage.

Inspection. In the output circuits 11 to 116, δ1. δ2. θ, α,
Only signals of components corresponding to β1 and δ2 are output,
Each corresponding gate circuit 12□-126 is opened.

Then, a 1ms clock signal is sent to the gate circuits 121-1.
Pass when 26 is open and click 13□~1
36 each.

The number of these pulses is stored in register 1 for the effective sampling time.
4 □ ~ 146, respectively D-A circuit 15 □ ~
At step 156, the digital value is converted into an analog value and sent to the arithmetic circuit 17 via the switching circuit 16.

The comparators 21 and 22 of the arithmetic circuit 17 sequentially compare the ratio of the time of each component to the effective sampling time.

When the value is 50% to 100%, the terminal 28 of the display 27
When it is 20 to 50%, a signal is sent to the terminal 29, and when it is less than 20%, a signal is sent to the terminal 30, and the signal is displayed on the corresponding lamp or the like.

Note that in the arithmetic circuit 17, registers 7.14° to 146
It is also possible to use the output directly to change the ratio using an analog value on a meter, or to display a specific number from the output of the D-A circuit 8°151-156.

Furthermore, when used for a special purpose such as sleep prevention, an alarm can be issued when the waveform generated during sleep exceeds a predetermined value.

In the embodiment described above, the clock signal for setting the effective sampling time and the clock signal for detecting the time of each component of the brain wave are inputted from the same clock pulse generator 1.

However, since the unit of effective sampling time is 30 seconds or 60 seconds, a clock signal with a sufficiently low frequency may be used, and the time for each component of the brain wave may be determined by using a high frequency Noritak signal. .

Since the present invention is configured as described above, the ratio of each component of an electroencephalogram can be detected correctly, and it is extremely useful as an electroencephalogram analyzer.

In addition, when exact numerical values are not required, the stepwise ratio setting circuit and the detection output can be compared and displayed using a comparator, which provides an excellent effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an electroencephalogram analysis device according to the present invention, and FIG. 2 is a detailed block diagram of the arithmetic circuit in FIG. 1. 1...Clock pulse generator, 2,121~1
26...Gate circuit, 3, 23, 24, 25...
...Inverter, 4,13. ~136...
・Counter, 5...Body movement detector, 6...
・Reset signal circuit, 7°14, ~146...
Register, 8, 15□~156...D-A circuit, 9...Brain wave detection circuit, 10...Cancel circuit, 111-116...Brain wave detection circuit for each component, 16... switching circuit, 17...
...Arithmetic circuit, 18.19,20...Resistance, 2
L22... Comparator, 26... NAND circuit, 27... Display, 28°29.30...
...Terminal.

Claims (1)

[Scope of Claims] 1. A body motion detector that is attached to a subject and detects body movements such as turning over of the subject, and a unit sample that is opened by the output of this body motion detector when there is no body movement. a gate circuit for passing a clock signal for setting the switching time; a counter for setting the effective sampling time by counting the number of clock signals passing through the gate circuit or for each unit sampling time by the reset signal circuit; an electroencephalogram detection circuit that is worn by the examiner and detects the original waveform of the subject's brain waves; and a cancellation circuit that is controlled to open and close by the body movement detector and cancels passage of the electroencephalogram information from the electroencephalogram detection circuit only during a period of body movement. , a detection circuit that detects brain waves for each component classified by frequency from the original waveform of the brain waves that have passed through this cancellation circuit, and a detection circuit that is opened and closed by this detection circuit to determine the brain wave detection time during the detection time of the brain waves for each component. a gate circuit that allows a setting clock signal to pass; a counter that detects the wave time of each component by counting the number of clock signals for each component that has passed through the gate circuit for each unit sampling time by a reset signal circuit; An electroencephalogram analysis characterized by comprising: an arithmetic circuit that calculates the ratio of each component wave detection time of the component wave time detection counter to the effective sampling time set by the sampling time setting counter. Device. 2 The circuit that detects each component of the brain waves classified by frequency from the original brain wave waveform detects the δ1 wave, β2 wave,
2. The electroencephalogram analyzer according to claim 1, comprising circuits for detecting θ waves, α waves, β1 waves, and β2 waves, respectively, and gate circuits are individually coupled to these detection circuits. 3 The arithmetic circuit includes a circuit that sets a predetermined percentage in stages with the effective sampling time as 100%, the outputs of these stepwise setting circuits, and the number of clock signals corresponding to the detection time of each component of the brain wave. 2. The electroencephalogram analysis device according to claim 1, further comprising a comparator for comparing corresponding outputs.