SU992024A1 - Reflexometer - Google Patents

Description

(54) REFLEXOMETER

one

The invention relates to medical technology, namely, devices for conducting electroneuromyographic studies.

A device is known for measuring the latent period of a central response, which includes an electrostimulator with electrodes, an amplifier of biopotentials with electrodes, and a recorder 1.

A disadvantage of this device is the manual measurement of the latent period of the central muscle response to the carriers after its registration. With the help of a baseline ruler, the distance from the irritation artifact to the impulse of the central section is measured on the carrier.

Closest to the present invention is a reflexometer containing a stimulator with electrodes and a series-connected amplifier of biocurrents with electrodes, a driver for controlling pulses and a time measuring unit 2.

The disadvantage of the known reflexometer is the impossibility of selecting the potential of the central (H) muscle response and stopping the time of the measuring unit to the previous change in the bioelectric activity of the muscle associated with its contraction (motor response).

The purpose of the invention is to measure the latent period of the central muscle response by highlighting its potential against the background of the motor muscle response.

The goal is achieved by the fact that a one-shot, connected between the stimulator output and the second input, is the time of the measuring unit, which contains a stimulator with electrodes and an amplifier of currents connected in series with electrodes, a control pulse generator and time 10 measuring unit.

At the same time, the measuring unit co15 holds a reset pulse shaper, a series-connected counting pulse generator, a coincidence circuit and an electronic counter, pulses, as well as a trigger trigger whose output is connected to the second input of the coincidence circuit, a reset input 20 to the reset pulse shaper, and and logic inputs are connected respectively to the output of the driver control pulses and the output of the one-shot.

The drawing shows a structural diagram of a reflexometer.

The reflexometer contains a stimulator 1 with electrodes and an amplifier 2 of biocurrents connected in series with electrodes, a driver 3 for control pulses and a time measuring unit, and a single vibrator 4 connected between the output of the stimulator 1 and the second input for the time of the measuring unit.

The measuring unit contains a shaper of 5 reset pulses, - a series-connected generator of 6 counting pulses, a coincidence circuit 7 and an electronic counter of 8 pulses, as well as a trigger 9. The output of the trigger 9 is connected to the second input of the coincidence circuit 7, the reset input is connected to the shaper of 5 reset pulses, and the control and logic inputs are connected respectively to the output of the shaper 3 of the control pulses and the output of the one-shot 4.

Reflexometer works as follows.

Cutaneous tin electrodes are used as stimulating electrodes. The active electrode (cathode) with a thickness of 2 mm and a diameter of 10 mm is placed on the irritated nerve area, and an indifferent electrode (anode) with a thickness of 2 mm and an area of 15 cm is placed on the opposite side of the limb more proximally. The indifferent electrode is wrapped in cotton cloth, which is impregnated with saline. From the stimulator 1 to the stimulating electrodes, imposed, for example, on the tibial nerve in the popliteal mac, electrical stimulus of 0.5 ms duration is fed in manual mode (by pressing the button by the experimenter) as its amplitude increases from 0 to 100 V.

Thus, from the surface electrodes of the brand FE-1 (Medicor), superimposed on the medial head of the gastrocnemius muscle inverted by the irritated nerve, the central response (H-reflex) of the muscle enters the biocurrent amplifier 2.

In dermal application of stimuli by stimulating electrodes to the nerve that innervates the muscle in manual start mode from the output of stimulator 1, a one-shot 4 is triggered by the leading edge of the control impulse, which creates a single pulse with a duration greater than the maximum value of the duration of the direct motor muscle response and less than the minimum value latent period of central (H) response. Regarding the muscle from which the indicated potentials are diverted and the duration of the pulse created by the single vibrator is set, for example, 20 ms. The leading edge of this pulse, which enters the logic input of the trigger 9, triggers the trigger trigger 9, which opens the coincidence circuit 7, which ensures the arrival of counting pulses from the generator 6

on the electronic counter 8 pulses. The countdown begins. The duration of a rectangular pulse taken from the single vibrator 4 determines the delay time for triggering the trigger 9 to return to its original state and switching off the time of the measuring unit by the forward motor response (M) pulse, which occurs at the threshold and above the threshold for motor fibers has a smaller latent period compared with the central (H) response of the same muscle. After the end of the delay time of the potential of the central response through the driver 3 to the input of the trigger 9, the trigger returns to the initial state, the coincidence circuit 7 closes, the time is stopped. After the readings from the electronic counter 8 are recorded, the experimenter resets the readings of the counter by pressing the button that starts the driver 5 of the reset pulse performed according to the standby multivibrator circuit. After this, the next measurement is made.

The proposed device makes it possible to directly measure the latent period of the central (H) muscle response, regardless of the simultaneous presence of a direct motor (M) response and to increase the reliability of the measurement results. It can be used in systems for automatic processing of biomedical signals.

Claims (2)

1. A reflexometer containing a stimulator with electrodes and a biocurrent amplifier with electrodes connected in series, a driver for controlling pulses and a time measuring unit, characterized in that, in order to measure the latent period of the central muscle response by highlighting its potential against the background of the muscle response of the muscle, A one-shot is inserted into it, connected between the output of the stimulator and the second input of the time of the measuring unit. 2. The reflexometer according to claim 1, characterized in that in it the time measuring unit contains a reset pulse shaper, serially connected counting pulse generator, a coincidence circuit and an electronic pulse counter, as well as a trigger trigger, the output of which is connected to the second input of the coincidence circuit, the reset input is connected to the reset pulse shaper, and the control and logic inputs are connected respectively to the output of the control pulse generator and the one-shot output. Sources of information taken into account in the examination 1. Methodology of electroneuromnographic studies. Ed. Badal on L. О., M., “Medicine, 1978, p. 9-10. 2. USSR author's certificate number 159938, cl. A 61 B 5/16, 1962. ъ