JPH0233379B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables the determination of circuit conditions related to the distribution of multiple electrodes attached to a living body including the head to arbitrary recording channels, biological signal amplification, etc. by setting at the input section. The present invention relates to an electroencephalograph using semiconductor switching elements.

In general, in medical electronic devices that monitor patients or diagnose diseases based on electrical signals induced from living bodies, a large number of electrodes attached to living bodies are arbitrarily combined according to various diagnostic logics selected or developed by doctors. At the same time, the biological signals induced during that time are amplified and recorded under arbitrary circuit conditions, that is, with arbitrary amplification degrees or filter characteristics. Therefore, setting circuit conditions including electrode combinations in medical electronic devices is not only complicated but also difficult work requiring accuracy. Particularly with electroencephalographs, 27 electrodes are attached mainly to the head, and the electrical signals obtained from these are combined and amplified as appropriate, and then recorded using a 17-channel pen recording section. Therefore, handling it is more difficult than you might imagine.

Therefore, in order to improve this operability to some extent, the combination of multiple electrodes attached to the head and each recording channel for electroencephalogram measurement can be arbitrarily written into random access memory (RAM) from the input section, and synchronized with channel switching. There is also a well-known brain wave pattern selector that can sequentially read out the contents of the RAM, set the circuit, and check the contents of the program by pressing the read key to display and confirm the contents of the program, if necessary. All of these are due to the circuit system for setting circuit conditions and displaying.
It was only possible to set simple circuit conditions.

In view of this point, it is an object of the present invention to provide an electroencephalograph that allows easy and diverse changes, settings, and selections of measurement patterns that define the circuit conditions of each recording channel.

Next, the present invention will be explained according to illustrated embodiments.

FIG. 1 is a main circuit diagram of the electroencephalogram according to the present invention, and numeral 11 shows the predetermined recording of electroencephalogram signals, respiratory wave signals, etc. in addition to electroencephalogram signals from a large number of electrodes attached to the subject's head. The electrode switching circuit 13 for outputting to the channel is composed of a latch circuit, a semiconductor switch, etc., and is composed of a preamplifier 2 and a main amplifier 3, which can adjust the high and low cutoff frequencies and gain of the filter using digital signals. 4 is a multi-channel pen recording section, 5 is a signal processing circuit that is composed of a microprocessor and controls the operation of the entire device according to a program stored in advance in read-only memory (ROM) 6, and 7 is an electrode. The circuit condition data of the switching circuit 1 and the preamplifier 2 are stored and read, and the data is stored in a non-volatile area that is rewritable and is driven by a battery so that it will not be erased even if the power of the device is turned off, and in this non-volatile area. A random access memory (RAM) consisting of a working area driven by the device power supply for reading or writing; This is a keyboard that commands the display of circuit conditions. The keyboard 8 has an encoder inside, and each pushbutton switch on the keyboard converts a control signal or data into a digital signal. Furthermore, 9 is a cathode ray tube control circuit that generates control signals for displaying circuit condition data in various formats on a cathode ray tube for measurement and programming; 10 is a monitor camera that mainly monitors the condition of the subject; 14 is a monitor camera 10 which amplifies the video signal from the cathode ray tube control circuit 9 and monitors a subject in another room if necessary.
This is a cathode ray tube display unit having a video switching amplifier circuit 11 and a cathode ray tube 12 through which horizontal and vertical synchronizing signals and video signals are introduced via the circuit 11.

The electrode switching circuit 1, the preamplifier 2, the signal processing circuit 5, the ROM 6, the RAM 7, the keyboard 8, and the cathode ray tube control circuit 9 have addresses for notifying the storage location of programs, circuit conditions, and display data necessary for the operation of each circuit. bus, a data bus for transferring program contents and data between each circuit, and a control bus for issuing commands from the signal processing circuit 5 to each circuit and requesting interrupt processing from each circuit to the signal processing circuit 5. connected to each other.

FIG. 2 shows the circuit configuration of the electrode switching circuit 1.
1 is an electrode data decoder, 22 is a channel address decoder, and 23 is a cross-point switch with a flip-flop (FF) provided at the intersection of the input line and the output line. There are 23 input lines for electroencephalogram signals (FP ₁ , EP ₂ , F ₃ , F ₄ ...) corresponding to the number of head electrodes on the keyboard, and 4 input lines for other biological signals such as electrocardiogram signals (X ₁ ~ X ₄ ) total 27
Consists of books. The output lines consist of two lines (G ₁ , G ₂ ) for each of the 17 channels. In synchronization with the memory write signal MW from the signal processing circuit 5, one of the output lines and the input line, respectively.
The FF is set, and therefore the output line and the input line are connected at the intersection where both FFs are set.

FIG. 3 shows an arrangement of pushbutton switches for selecting, setting, and changing a number of measurement patterns and setting circuit conditions to the circuit on the keyboard 8, which functions as an input section for commanding the operation of the apparatus. 31 is a group of various biological signal switches, 32 is a head electrode switch group, 33 is a channel switch group, 34 is a pattern switch group, 35 is a group of circuit condition setting switches for the preamplifier 2, and SET is a circuit condition setting circuit. This is a setting switch for writing circuit conditions into the non-volatile area of the RAM 7. Each switch of the head electrode switch group 32 is placed on a head diagram simulating the head in correspondence with its actual position. The amplifier circuit switch group 35 includes GAIN for adjusting the gain of the preamplifier 2, Lo Cut for adjusting the low-frequency cutoff frequency of the filter, and Hi Cut for adjusting the high-frequency cutoff frequency of the filter. Consists of switches,
There are pairs of push button switches for step up and step down respectively.

FIG. 4 shows the circuit configuration of the cathode ray tube control circuit 9. Data DB0 to DB7 such as display format and circuit conditions read from the non-volatile area and work area of RAM 7 are first stored at addresses AB0 to MB10, which are to be stored, through an address bus and multiplexer 41, and then transferred to the refresh memory 42. After being sent to and specifying the address,
The data is sent to the reset memory 42 via the data bus. This refresh memory 42 has a memory capacity equivalent to one screen of a cathode ray tube.
When all the data to be displayed now is stored in the refresh memory 42, the multiplexer 41 supplies address signals MA0 to MA9 from the control section 43 to the refresh memory 42 in response to a control signal sent from the signal processing circuit 5 through the control bus. and read out the stored data. The read data is temporarily held in the latch circuit 44 and converted into a character signal by the character generator 45. The signal is then converted into a serial signal by a parallel-to-serial converter 46, and further converted into a video signal for display on a cathode ray tube by a video control circuit 47. The parallel-to-serial conversion circuit 46 and the control section 43 are each synchronized with an 8MHz clock generator 48 and a synchronous counter 49 that counts down the clock.
The data DB0 to DB7 are also applied to the control section 43, and display control is also performed as a command signal from the signal processing circuit 5.

The electroencephalograph having the circuit configuration described above operates as follows.

When the power switch (not shown) is turned on, the signal processing circuit 5 reads display format data from the non-volatile area of the RAM 7 and sends the address and data to the cathode ray tube control circuit 9 in accordance with a startup processing routine preprogrammed in the ROM 6. Inform. In the cathode ray tube control circuit 9, this data is temporarily stored in the refresh memory 42 in accordance with the address designation, and then the display format shown in FIG. 5 is displayed on the cathode ray tube 12 through the above-described processing steps. However, the electrodes G ₁ and C ₂ of each channel are displayed as CAL (calibration).

In addition, in the display format of Fig. 5,
CAL50μV indicates the reference voltage or calibration voltage to be left in the recorded brain wave waveform, and R-
LE indicates the grounding state of the electrodes, and in this example, it shows that the electrodes attached to the right ear (R) and the left ear (L) are grounded.

Next, for example, if you want to measure using measurement pattern 5,
When you press pattern switch _P5 on keyboard 8,
A key interrupt signal is applied from the encoder of the keyboard 8 to the signal processing circuit 5 through the control bus. When the signal processing circuit 5 receives this interrupt signal, the program jumps to a key processing routine, and the keyboard is specified via the address bus. Next, from keyboard 8, pattern switch
Data corresponding to _P5 is sent from the encoder to the signal processing circuit 5 via the data bus. Through this series of operations, the signal processing circuit 5 learns that the keyboard 8 requests the measurement pattern 5, and sends it to the ROM.
According to the program stored in advance in 6,
The circuit condition data of the measurement pattern 5 is read from the nonvolatile area of the RAM 7, transferred to the working area of the RAM 7, and also transferred to the refresh memory 42, and the measurement pattern is displayed on the cathode ray tube 12 in the display format shown in FIG. 5 circuit conditions are displayed. In other words, the correspondence between electrodes C ₁ and C ₂ of each channel in measurement pattern 5, the gain of preamplifier 2,
You can list the filter's reduced cutoff frequency LC, high cutoff frequency HC, CAL voltage, etc.

Next, when the setting switch SET on the keyboard 8 is pressed, the circuit condition data of measurement pattern 5 is transferred from the working area of RAM 7 to the electrode switching circuit 1 and preamplifier 2 through the address bus and data bus according to a predetermined program, and then through the control bus. The transmitted MW pulses are set (loaded) to each circuit through the operation process described above. As a result, the electrodes are connected and the amplification degree and filter characteristics are set as indicated. Furthermore, when a record switch (not shown) is turned on, biological signals such as brain waves, electrocardiograms, and respiratory waves are recorded in parallel on the multilayer pen recording section based on the selected measurement pattern. Similarly, for other measurement patterns 1 to 4 and 6 to 8, the corresponding pattern switches P ₁ to _{P 4} and
Can be selected from P ₆ to P ₈ .

The electrode connections for measurement patterns 1 to 8 are set in advance to standard conditions, and when used, the preamplifier 2
After setting the circuit conditions, the pattern switch
A wide variety of measurements are possible by selecting P ₁ to P ₈ . In addition, according to the present invention, as will be described in detail below, various programs for changing the standard measurement pattern and setting free measurement patterns, that is, circuit conditions, are displayed on the keyboard 8 based on the display on the cathode ray tube. This is easily possible.

First, the measurer selects channel 1 of pattern 5, for example.
If you want to change the circuit conditions of preamplifier 2 of 1,
Press pattern switch _P5 to display measurement pattern 5.
is displayed on the cathode ray tube (Figure 5). Next, when the channel switch Ch11 is pressed, a key interrupt signal is applied to the signal processing circuit 5 through the control bus, and the execution program moves to the key processing routine. As a result, keyboard 8 is specified through the address bus, and then channel switch Ch11 is specified.
Data corresponding to 1 is taken into the signal processing circuit 5 from the encoder via the data bus. The signal processing circuit 5 puts new data and address buses based on this data on the data bus and address bus, respectively, and applies them to the cathode ray tube control circuit 9. The cathode ray tube control circuit 9 changes the characters of Ch11 on the cathode ray tube 12 to "white" characters based on these data. Next, when the gain setting switch GAIN□↑ or □↓ is pressed, the cathode ray tube display changes to the display format shown in FIG. That is, try to set
GAIN characters and current circuit conditions are "white"
is displayed. Furthermore, by pressing the setting switch GAIN□↑ or □↓ as many times as necessary, the gain will increase or decrease in steps. At this time, the "white" text for the gain can be moved up or down to check the setting value. Similarly, if you want to change the characteristics of the filter's low and high cutoff frequencies,
Furthermore, desired circuit conditions are set by pressing Lo Cut and Hi Cut a predetermined number of times. When all the circuit conditions are set to the desired values as described above, press the setting switch SET. Then, the cathode ray tube display returns to the display format shown in FIG. Set. still,
In this case, it is possible to make all the circuit conditions the same except for the 11 channels, which belong to the gain, low frequency, and high frequency cutoff frequency setting switches.
When the ACC (All Channel Control) switch (not shown) is set to the desired value, the displays other than Ch11 will change to this value, and all circuit conditions will be memorized and set to the circuit along with the gain of the 11 channels set earlier. be exposed.

Further, if necessary, the standard electrode connections of measurement patterns 1 to 8 can be changed by the following operations. First of all,
When the lock key (not shown) is turned on, the cathode ray tube display changes to the display format shown in FIG. 7 (the electrode numbers PAT-2 to PAT-8 are omitted). This display format shows the current state of electrode connection for each measurement pattern. for example,
If you want to change the electrode connection for channel 1 of measurement pattern 1, press pattern switch P ₁ and channel switch Ch 1, and then switch the desired electrode switch 2.
When you press one of the electrodes, that electrode will be displayed in the G ₁ and G ₂ columns in order. In this case, it is possible to press the button again, but once the setting switch SET is pressed, the display contents are transferred from the working area of the RAM 7 to the non-volatile generation area and stored. Other channels can be changed by pressing the channel switch and electrode switch in the same way, and then pressing the setting switch SET each time. For other measurement patterns, first press the desired pattern switch and perform the same operation. After changing the measurement pattern and turning off the lock key, the display format returns to FIG. 5.

To temporarily change the electrode connection, press the desired pattern switch with the lock key turned off, and set the desired channel switch and electrode switch in the display format shown in FIG. In this case, the changed contents are only stored in the working area of the RAM 7, so if another measurement pattern is selected after the measurement is completed, the changed contents will be restored.

Furthermore, in the device according to the invention, free patterns can be set in addition to the standard measurement patterns 1 to 8. To do this, first press the pattern switch Freee to change to the display format shown in Figure 5 (although the title is different). Then, the channel is set by the channel switch, and the electrodes G ₁ and G ₂ to be connected are set by the electrode switch. Further setting switch SET
Press to store the settings in the nonvolatile area of RAM 7 and set them in the electrode switching circuit 1. In this way, electrode connections are set for each channel.
The circuit conditions for the preamplifier 2 are set in the same way as for the standard measurement pattern.

Video amplification switching circuit 1 at the start of measurement or during measurement
1 to the monitor TV 10 side, it is possible to accurately grasp eye blinks, body movements, etc. that cause artifacts (noise) of the subject in another room, making it easier to analyze recorded data, and eliminating unnecessary measurements. gone,
Furthermore, measurement accuracy is also improved. In particular, if an infrared monitor camera is used, it is very effective because it allows you to see the state of the subject, which cannot be directly observed, even when measuring so-called sleep brain waves, which are obtained from a sleeping subject in a dark room. It is true.

Although the above-mentioned embodiment was a case of an electroencephalograph in which electrical signals induced from 27 biological electrodes were appropriately combined and recorded by a 17-channel pen recording unit, the present invention is limited to this embodiment. This method can also be implemented in electroencephalographs with a small number of electrodes or channels.

As is clear from the above description, the present invention not only allows a wide variety of selections, checks, settings, and changes of measurement patterns including amplification characteristics, but also monitors and diagnoses based on the appropriate display form for each occasion on the cathode ray tube. The circuit conditions frequently used in the diagnostic logic selected by the doctor are stored in advance, and can be read and set with one or two key operations, so that precise measurement of brain wave signals can be easily performed. Become. In addition, since the head electrode switch group on the keyboard is arranged to imitate the actual arrangement of electrodes on the head, when selecting a combination of electrodes on the electroencephalogram main body, it is possible to The correspondence with the electrodes attached to the device can be clearly seen at a glance, making it easy to perform precise brain wave measurements that correctly match the diagnostic logic selected by the attending physician. Furthermore, by switching the video signal of the patient's monitor camera to the cathode ray tube, it is possible to accurately grasp the cause of artifacts or other conditions of the subject, and analysis of electroencephalogram measurements can be performed easily and with high precision.

[Brief explanation of drawings]

Fig. 1 is a main circuit diagram of an electroencephalogram according to the present invention, Fig. 2 is a circuit diagram of a switching circuit thereof, Fig. 3 is a switch arrangement diagram of a keyboard according to the present invention, and Fig. 4 is a cathode ray tube control diagram in Fig. 1. Circuit diagram, 5th
Figures 7 to 7 show the display format of circuit conditions on a cathode ray tube. 1... Electrode switching circuit, 2... Preamplifier, 3...
...Main amplifier, 4...Recording section, 5...Signal processing circuit, 6...ROM, 7...RAM, 8...Keyboard, 9...CRT control circuit, 10...Monitor camera, 11...Video switching Amplification circuit, 12...
...Brown tube, 13...Amplification circuit.

Claims (1)

[Claims] 1. An electrode switching circuit that distributes signals induced from a plurality of electrodes attached to a living body including the head to arbitrary recording channels, and an amplifier circuit that amplifies the output of the electrode switching circuit. , a recording unit that records the amplified signal for each channel, a random access memory including a nonvolatile area that stores circuit condition data of both circuits, and head electrodes arranged to imitate the actual arrangement on the head. The switch includes at least a group of switches, and commands to read circuit condition data from the non-volatile area, write circuit conditions to the non-volatile area, set circuit conditions to the circuit, and display circuit conditions in a fixed display format. a keyboard, a cathode ray tube control circuit that generates a signal for displaying circuit condition data to be displayed on a cathode ray tube in a fixed display format, a signal processing circuit that causes the keyboard to operate in accordance with the commands of the keyboard according to a predetermined program, and the cathode ray tube. An electroencephalograph comprising: the cathode ray tube display section connected to a control circuit, and further comprising a changeover switch capable of inputting a video signal from a monitor camera for monitoring a subject.