P-2-07-01
EFFECTS OF TEMPERATURE ON MOTOR UNIT ACTION POTENTIALS
Soo-Kyung Bok, Min Kyun Sohn (Chungnam National University, Taejon, Korea)
This study was performed to evaluate effects of temperature on motor unit action potentials(MUAP) by automatic method in the 20 healthy adults. 20 separate motor unit action potentials were recorded in the biceps brachii muscle with concentric needle electrodes at three different skin temperature. The arm was cooled to below 24℃ using coldpack and warmed with an infrared above 38.5℃.
As temperature was decreased, amplitude, duration, area, spike duration, spike area, rise time, phase and turns of motor unit action potentials were increased and these changes were statistically significant except turns. Especially more significant changes were developed by cooling than warming of muscle. At three temperature settings, the rise time was inverse relationship with the amplitude, and number of phases and turns.
Therefore the temperature is very important considering factor and must be standardized or controlled during analysis of motor unit action potentials.
P-2-07-02
COMPARISON OF THE ACTIVE ELECTRODE AND SURFACE ELECTRODE IN MOTOR CONDUCTION STUDY
M. Arita (Tokyo Metropolitan Rehabilitation Hospital, Tokyo, Japan*1), S. Sonoda(*l), Y. Tomita (Keio University*2), O. Takahashi(*l), Y. Igarashi(*2), R. Imahori(*2), Y. Muraoka(*2), T. Ota(*1), F. Hotta(*1), S. Tochigi (Tokyo Metropolitan college), N.Chino(*2)
The efficiency of the active electrodes we made has been compared with the routine surface electrode of Ag-AgC1 in 5 health volunteers. Since the active electrode composed of an OP-amplifier and a battery has much higher impedance as compared with skin, it can record motor action potentials without preparing the skin or the use of jelly.
The median motor potentials (MMPs) were recorded from thenar muscles with the routine and active electrodes twice within a week. We measured the latency, amplitude, area, conduction velocity of MMPs, and evaluated the waveform, repeatability. No significant difference was found in the latency and velocity with both electrodes. But the waveforms recorded by the active electrodes were more symmetrical at a border of baseline, larger in amplitude and area, and better in repeatability than those by the routine electrode. When three examiner measured two conduction velocities with both electrodes, it took shorter time with the active electrode than with the surface electrode. The active electrode seems to be practically useful in motor conduction study.
