JPH0657202B2 - EEG recording device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electroencephalogram recording apparatus, and in particular, by preparing an electroencephalogram graph consisting of an electric potential and each electrode part, and recording the electroencephalogram in the form of a two-dimensional image, The present invention relates to an electroencephalogram recording device that can be easily understood intuitively and visually.

[Prior Art] Conventionally, an electroencephalogram is generally recorded by inducing a change in electrical activity of the brain over time from electrodes on the scalp, and a fluctuating potential difference is plotted on the vertical axis and time on the horizontal axis, and approximated to a sine wave. It is displayed as a waveform curve. As an actual recording method, since the electroencephalogram is a minute electric potential in the unit of μV, it is greatly amplified by the electroencephalograph, and the up and down movement of the pen tip is drawn in a wavy pattern on the flowing paper. This waveform is represented by height (amplitude μV) and width (duration, period, millisecond), and frequency (cycle) is 1 / period.

In order to read brain waves from the waveforms recorded as described above, it is generally assumed that the brain waves are drawn with a width of 3 cm for 1 second, so the width of the waves of the recorded waveform is within 3 cm. The frequency is calculated by measuring the ratio of the number of times into the scale, etc., and the amplitude is calculated by measuring the length on the scale and converting it to voltage.

[Problems to be Solved by the Invention] However, in order to read an electroencephalogram, it is necessary to read each page of the recorded electroencephalogram, but it takes time to read all of a large number of waveforms. However, there is a drawback that it is difficult to make a quantitative determination because accurate reading requires skill and individual differences occur.

On the other hand, recently, some methods have been used to display the electric potential by pattern or color on a color graphic CRT by performing addition analysis by a computer of evoked potentials of the electroencephalogram, but the display is not quantitative and the discrimination is inaccurate. There is an unclear defect.

Further, the present applicant has already proposed, as a method for solving such a drawback, Japanese Patent Application No. 60-5890 (Japanese Patent Laid-Open No. 61-164).
No. 542), the electroencephalogram is represented by δ, θ, α ₁ , α ₂ ,
For each frequency band of β ₁ and β ₂ , the vertical axis represents the potential, and the horizontal axis represents the line graph of each electrode part, so that quantitative,
We proposed an EEG recording device that can be intuitively measured. This device uses an electroencephalograph, which converts an analog signal of the electroencephalogram measured by the electroencephalograph into a digital signal by an interface device, calculates the digital signal by a personal computer, and displays the graph on the screen. Recording device.

However, in this electroencephalogram recording device, the device becomes large and complicated because the conventional electroencephalograph is used, and the analog signal of the electroencephalogram signal obtained by the electroencephalograph is amplified and corrected so that the electroencephalogram is recorded on paper in a wave shape. In addition, since the electroencephalogram analog signals obtained by different models of electroencephalogram are different, in order to display a clear graph of the electroencephalogram on the screen of the personal computer, the interface device must be compatible with the electroencephalogram signal to be captured. Must be,
In addition, there was a drawback that the interface device had to be changed to suit the model of the electroencephalograph used.

The present invention has been completed as a result of conducting research in view of such conventional problems, and does not use a large and complicated electroencephalograph as in the prior art. It is a device that has the advantage that it does not need to change the analysis unit, the electrode is attached to each measurement site of the examiner's scalp, the electroencephalogram signal obtained from the electrode is amplified by the preamplifier, and further analyzed by the analysis unit, EEG on the CRT of the personal computer δ, θ, α ₁ , α ₂ , β
_A compact device that can directly display the electroencephalogram signal obtained from the electrodes by displaying the potential on the vertical axis and the line graph on the horizontal axis for each electrode site for each frequency band of ₁ and β _2. An object of the present invention is to provide an electroencephalogram recording apparatus that can quantitatively and intuitively and accurately measure an electroencephalogram and that is easy for general people to explain and understand.

[Means for Solving Problems] and [Operation] That is, the present invention relates to (A) an electrode that is attached to each induction site of the scalp to capture an electroencephalogram signal, and (B) an electroencephalogram signal captured by the electrode. A preamplifier that amplifies the analog signal,
(C) A buffer amplifier for removing distortion of the electroencephalogram signal amplified by the preamplifier, a programmable amplifier for compensating for variations in current sensitivity amplified by the preamplifier, and an input of the number of channels equipped with electrodes A 12CH multiplexer that switches to input for each channel and takes in an analog signal from the electrode, an A / D converter that converts the analog signal obtained from the preamplifier into a digital signal,
A data collection control device for controlling the 12CH multiplexer to switch the channels to operate the A / D converter, fetch data for the number of channels with electrodes attached, and control the interface to send the data to a personal computer. An electroencephalogram characterized by comprising an analysis unit and (D) a personal computer that displays the electroencephalogram by taking in the digital signal and computing the measurement data, and displays the electroencephalogram on the vertical axis and the horizontal axis on a line graph of each electrode site. It is a recording device.

Hereinafter, the present invention will be described in detail.

The electroencephalogram recording device of the present invention is 12 or input from the electrode.
The 16-channel biosignal is amplified by a preamplifier and sent to a personal computer through an analysis unit for analysis, and the electroencephalogram is automatically recorded from the results.

FIG. 1 is a block diagram showing an example of an electroencephalogram recording apparatus according to the present invention. The apparatus is an electrode, a preamplifier, a buffer amplifier, a programmable amplifier, a 12CH multiplexer, and an A / D.
It consists of a converter, interface, CPU, computer body, CRT, printer, photostimulator and data analysis software, and the electrodes are connected to the preamplifier.

In FIG. 1, electrodes are attached to each measurement site on the scalp to capture an electroencephalogram signal, and the captured electroencephalogram signal is amplified by a preamplifier as an analog signal.

Electrodes conform to international 10-20 method for EEG measurement
It is installed by monopolar induction method with 12 or 16 channel input. In addition, as the electrode, a commercially available electrode for measuring an electroencephalogram can be used.

The present invention directly measures an electroencephalogram using the electrode without using a conventional electroencephalograph. In the electroencephalogram measurement, the electrode device is a monopolar induction method on the scalp by the international M10-20 method.
12 parts FP ₁ , FP ₂ , F ₇ , F ₈ , C ₃ , C ₄ , T _{5
· T 6 · O 1 · O} 2 · Fz · Pz mounted electrodes to perform the measurement,
The electroencephalogram signal derived from the electrodes is sent to the preamplifier by a pre-embedded pattern, adjusted and amplified so that the electroencephalogram signal between the electrodes of the incorporated pattern can be displayed in the most suitable state, and then amplified. The EEG signal is sent to the analysis unit, A / D converted, and then sent to the computer.

In the present invention, an electroencephalogram signal having an extremely low electric potential of several μV to several tens of μV is normally taken in from the electrode because the resistance value of the scalp to which the electrode is attached is high, but the preamplifier adjusts the electroencephalogram signal to amplify the signal. To do.

An example of the specifications of the preamplifier is as follows: impedance 5 megaΩ FET input / output 20 times amplification before and after input noise 0.67 μV.

In the present invention, the analysis unit has a function of converting an analog signal of the brain wave signal amplified by the preamplifier into a digital signal and sending the digital signal to the personal computer.

The analysis unit consists of a buffer amplifier, a programmable amplifier,
12CH multiplexer, A / D converter, interface, CPU, data analysis software, etc.

The buffer amplifier is a buffer amplifier and functions to remove the distortion of the electroencephalogram signal amplified by the preamplifier.

The programmable amplifier corrects the variation in current sensitivity amplified by the preamplifier.

The 12CH multiplexer is a device that switches the input of 12 channels to the input for each channel and takes in an analog signal from the electrodes. The switching time is 50 μSEC.

The A / D converter (AD converter) converts the analog signal obtained from the preamplifier (preamplifier) into a digital signal.

The CPU (data collection control device) controls the 12CH multiplexer to switch the channel and A / D
The converter is activated, the data for 12 channels is taken in, and the interface is controlled to send the data to the personal computer.

The interface is a connector for connecting a personal computer.

Analysis software is software that analyzes data.

Next, an example of the specifications of the analysis unit used in the present invention is as follows. Input channel 12 channels Input impedance 100 KΩ A / D conversion time 200 μ / sec A / D conversion accuracy 12 bit.

FIG. 2 shows an example of a circuit diagram of the analysis unit.

Further, FIG. 3 is a block diagram showing an example of the control unit of the analog-digital converter.

The specifications are as follows: CPU: 8086-2, 8 MHz (16bit) ROM: 96 KByte RAM: 640 KByte (Main memory) FDD: 5 INCH 6.4 MB × 2 ADC: 12 bit input ± 250 mV The computer is connected to the analysis unit, calculates the measurement data sent from the analysis unit, and displays the electroencephalogram on the line graph of the potential on the vertical axis and the electrode portion on the horizontal axis.

The personal computer consists of the computer body, color display, keyboard, 10 MB fixed disk device, printer, and so on.

A specific example of the personal computer used in the present invention is as follows. OA personal computer C-7000D, memory
256KB to 384KB can be mentioned.

Next, the specifications of the personal computer used in the present invention are shown below.

〇 Computer main unit Memory capacity ROM 8K bytes RAM 384K bytes Color CRT output 640 × 480 dots Palette function Simultaneous 8 color display Printer output 24 × 24 dots 120CPS Calendar clock Built-in power supply AC100V ± 10% Power consumption 0.9KVA Weight 23kg Large Size 480 (W) × 445 (D) × 165 (H) mm 〇 Color display section 12-inch cathode ray tube Display colors 83 colors including three primary colors, 8 colors, and intermediate colors Screen configuration Graphic screen × 9 + character screen Power supply AC100V ± 10 % Power consumption 90VA or less Weight 12kg Large 320 (H) × 415 (D) × 347 (W) With tilt base Number of displayed characters 80 characters × 24 lines × 9 screens 〇 Keyboard Key layout Standard JIS (with numeric keypad) Output data JIS 8-bit code (parallel) Weight 2.3 kg 〇 10MB Fixed disk device Storage capacity 10 megabytes Data capacity 1000 people 〇 Printer printing speed 80 characters / second Printing method Dot matrix impact both Number of prints 80 characters / line 66 lines / page Power supply AC100V ± 10% Power consumption 120VA Weight 16kg Large 570 (W) × 455 (D) × 175 (H) Next, the recording of the electroencephalogram of the present invention A method of recording an electroencephalogram using the device will be described. FIG. 4 is a flow chart showing a method for recording an electroencephalogram. In FIG. 4, first, 12-channel biosignals input from electrodes attached to each induction portion of the scalp are taken into a personal computer via a preamplifier and an analysis unit.

The measurement conditions are fixed for 5 seconds per acquisition time (4.88 msec x
1024), and set the acquisition count range to 1 to 100 times.

Next, the number of acquisitions is set, and the measurement data is stored in real time from the electrode to the main memory of the personal computer C-7000D via the preamplifier and the analysis unit.

Number of channels 12 channels Sampling clock 4.8ms Number of samplings 1024 points / channel Converts the time series data stored in the main memory into a complex Fourier series by the fast Fourier transform (FFT) and calculates the power spectrum.

FET operation accuracy 32-bit frequency resolution 0.5 Hz Frequency band 0 to 80 Hz The power spectrum obtained as a result of the operation is stored in a fixed disk. The power spectrum calculation of the sampled data is performed every 5 seconds, and the operation of storing the result is repeated a set number of times.

When the power spectrum for the set number of times is stored,
The average power spectrum equally divided by the number of times is displayed as a graph on one screen simultaneously for 12 channels.

The power spectrum is written into the measured value master file of the fixed disk for each channel and frequency band, and the measured value master file is read and the potential distribution chart and the vertical axis of the potential 0-50 μV and the horizontal axis of each electrode part 1-12 channel. Create SS graphs I and II, which are EEG graphs of line graphs.

Frequency band classification δ wave 2.0 to 3.8Hz θ wave 4.0 to 7.8Hz α ₁ wave 8.0 to 9.8Hz α ₂ wave 10.0 to 12.8Hz β ₁ wave 13.0 to 19.8Hz β ₂ wave 20.0 to 29.8Hz Potential distribution chart and SS graph I , II is N from the menu screen
o. By specifying, the measured value master file is read, the color is displayed on the CRT screen, and the process of printing hard copy on the printer is performed.

In this way, the electroencephalogram can be recorded on the electroencephalogram graph in which the vertical axis represents the potential and the horizontal axis represents the line graph of each electrode site.

It is also possible to provide an optical stimulator and give an optical stimulus to the examiner at the time of measuring the electroencephalogram to analyze the electroencephalogram signal at that time.

[Examples] Next, the present invention will be described more specifically with reference to Examples.

Example 1 A terminal of a commercially available electroencephalograph electrode was connected to the preamplifier, the preamplifier was connected to the analysis unit, and the analysis unit was connected to a personal computer (National Panafacom C-7000D). Using the device
An electroencephalogram was recorded according to the procedure shown in Table 1.

Table 2 shows the menu No. The outline of is shown.

[Processing procedure] ○ Input of examiner data When you select menu No.1 from the menu screen, the following items are displayed on the screen.

Measurement data is collected by specifying the NUMBER of detection.

-Electroencephalogram measurement Data is automatically collected from the electrodes and the date and time are displayed.

The number of acquisitions is collected by specifying the COUNT number.

Next, the start of calculation and the display during calculation are performed. The calculation is repeated by taking in the signals of all channels for 5 seconds, calculating the power spectrum, and adding the power spectrum to the power spectrum obtained previously. One count for 5 seconds, 100 counts can be calculated, and any count can be specified. The capture start time is automatically displayed, and the capture end time is automatically displayed.

〇 Power spectrum graph Select menu No.2 from the menu screen to display the power spectrum graph screen. The 12 channel power spectrum result is displayed. The vertical axis shows the power, and the horizontal axis shows the frequency of 0 to 80 Hz and the scale of 5 Hz. Calculations and counts are displayed.

-Potential distribution map When you select menu No.3 from the menu screen, the potential distribution screen is displayed. Display the potential distribution map for each frequency. In this case, the magnitude of the potential of the power spectrum is 6
The potentials are compared according to patterns and the frequency bands are compared according to color.

Delta band (blue) Frequency 2.0 to 3.8Hz Theta band (purple) Frequency 4.0 to 7.8Hz Alpha band (red) Frequency 8.0 to 12.8Hz Beta band (green) Frequency 13.0 to 29.8Hz 〇 SS Graph I From the menu screen, select Menu No. Select .4 to display the screen. If you want to display a normal person graph, specify Y. If you do not, specify N.

In the normal person graph, the average potential of each channel obtained by the minimum to maximum white average black calculation is displayed as a line graph of the potential on the vertical axis and the electrode part on the horizontal axis.

You can enter a normal person graph and compare it with the graphs of each age group in their 20s and 60s. (The age-specific graph is displayed according to the age of the examiner.) Six frequency bands δ, θ, α ₁ , α ₂ , α ₁ , β ₂ , β ₂ are simultaneously displayed.

The first red, the second yellow, the third green, and the fourth blue can be displayed for four times, and comparative examination can be performed. In addition, the normal graph is displayed on the SS graph I, and the examiner's data can be compared and examined.

〇 SS Graph II Select the menu No.5 from the menu screen to display the screen. If it is desired to display the normal person graph, Y is designated. If not, N is designated and the frequency band is designated as NO.

From the SS graph I, one arbitrary frequency band of δ, θ, α ₁ , α ₂ , β ₁ , β ₂ can be selected and displayed.

From SS graph I, the display of SS graph II in the delta wave band is shown in FIG.

From the SS graph II, it is possible to display a normal person graph and compare the δ wave band of the examiner. An example thereof is shown in FIG.

〇Electric potential list by frequency band Select menu No.6 from the menu screen and the screen of measured data value of 12 channels by frequency band is displayed.

A list of potentials for four times by the examiner is displayed.

○ SS Graph III When you select menu No.7 from the menu screen, the vertical axis shows the potential and the horizontal axis shows the time screen.

It is possible to measure the time course of the biopotential and observe the function.

〇Registering the inspector Select menu No.8 from the menu screen to display the screen. No. Select and register / correct the name, date of birth, and gender of the examiner.

〇Registration of normal person graph Select menu No.10 from the menu screen to display the normal person screen.

Specify the frequency and register the average value, maximum value, and minimum value for each 12 channels.

Example 2 Clinical Application Example (Cerebral / Peripheral Circulatory Disorder Improvement Agent Administration Example) Using an S / S graph system, the EEG during resting eyes was compared with an examiner aged 40 years or older who seems to have cerebral arteriosclerosis associated with a mental disorder. As a result of analyzing 8 counts (40 seconds), the examiner who showed potential fluctuation in the S / S code range in any band
Forty-eight patients were treated with dihydroergotoxin mesylate 6 mg / day 4 times each before administration (purple), 4 weeks after administration (green), 8 weeks after administration (red), and 12 weeks after administration (yellow). At that time, an electroencephalogram analysis was performed in the same manner as in Example 1 and compared with the S · S code. Δ, θ, α ₁ , α ₂ , and β of the examiner and normal person
Line graphs showing comparison of ₁ and β ₂ waves are shown in Fig. 7 (a) to (f).
Shown in.

As a result, the high potential in the theta (θ) and beta (β) bands before administration (purple) was observed to change from 4 weeks (green) after administration, especially at 12 weeks (yellow). , The effect after administration became closer to the S / S code range than before administration, and clinical symptoms tended to improve, indicating an interesting correspondence between the analysis results and clinical symptoms.

E / E / G It is a display for 12 seconds within 40 seconds of each analysis before (top) and 12 weeks (bottom) after administration.

[Effects of the Invention] As described above, the electroencephalogram recording apparatus of the present invention can display and record the electroencephalogram by plotting the potential on the vertical axis and the line graph of each electrode portion on the horizontal axis, and thus can be recorded as follows. It has an excellent effect.

(1) Do not use a large and complicated EEG as in the past
Therefore, it is not necessary to change the analysis unit of the recording device by the electroencephalograph used conventionally, and it is possible to easily and accurately record the electroencephalogram with a compact device that can directly display the electroencephalogram signal obtained from the electrode on the screen. You can

(2) Since the electroencephalogram can be quantitatively and objectively displayed, the electroencephalogram analysis result can be visually and intuitively understood, and the brain function can be observed electrically.

(3) As a clinical application of the present invention, the electroencephalogram analysis of the examiner can be performed to measure the brain function, and the progress of diagnosis and treatment can be observed by comparing with the SS graph.

(4) Since the EEG recording is displayed as a line graph,
The electroencephalogram can be measured accurately and quantitatively, and the measurement error does not occur by the measurer as in the past.

(5) EEG of normal person from 20 years old to 60 years old is measured, and a line graph of EEG of normal person by potential is created for each waveform,
Based on this, clinical EEG detection in the psychiatric field is performed, and how much the EEG of the subject is deviated from the EEG pattern of a normal person is compared, and not only treatment of a sick person but It can be applied to the examination of the working of the brain function and other areas.

(6) The brain waves can be automatically recorded by a program.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an electroencephalogram recording apparatus of the present invention, FIG. 2 is a circuit diagram of an analysis unit, and FIG. 3 is a configuration diagram showing an example of a control unit of an analog / digital converter.
FIG. 4 is a flow chart showing a recording method of the electroencephalogram, FIG. 5 is a line graph of δ wave of the examiner, FIG. 6 is a line graph showing comparison of δ wave of the examiner and normal person, and FIG. 7 (a) (F) shows line graphs of δ, θ, α ₁ , α ₂ , β ₁ , and β ₂ waves of one examiner by drug treatment.

Claims (1)

[Claims] 1. (A) An electrode that is attached to each induction portion of the scalp to capture an electroencephalogram signal, (B) a preamplifier that amplifies an analog signal of the electroencephalogram signal captured by the electrode, and (C).
A buffer amplifier that eliminates the distortion of the electroencephalogram signal amplified by the preamplifier, a programmable amplifier that corrects the variations in the current sensitivity amplified by the preamplifier, and the number of channels with electrodes attached 12C that switches to the input of and acquires the analog signal from the electrode
An H multiplexer, an A / D converter for converting an analog signal obtained from the preamplifier into a digital signal,
An analysis having a data collection control device that controls a 2CH multiplexer to switch channels to operate an A / D converter, capture data for a number of channels with electrodes attached, and control an interface to send data to a personal computer Recording of an electroencephalogram comprising a unit and (D) a personal computer that displays the electroencephalogram by taking in the digital signal and calculating measurement data, and displaying the electroencephalogram on the vertical axis by the potential and on the horizontal axis by a line graph of each electrode site. apparatus.