This is to reveal the normal variations of decrement or increment of potentials in the low rate repetitive stimulation test which was introduced by Desmedet in 1973.

12 healthy Koreans ranging in age between 25 and 28 were used.

The procedure and results obtained were summarized as follows:

1) The setting of EMG machine(BASIS O.T.E.) was in 5ms and 5~10 mV/div. and the repetitive stimulation program was used.

2) The surface electrodes were attached to abductor digiti quinti muscle of dominant hand and supramiximal stimulations were applied to the ulnar nerve at the wrist with fixation of the electrodes and hand as possible.

3) 5 times procedures were performed with 8 sequential stimulation in 3 Hz and taken rests for 30 second between the procedures.

4) The differences between the 1st and 5th potential in percentage were estimated.

5) The mean value of differences was 2.9% increment, with ranging in distribution from 8.3% decrement to 12.9% increment and the standard deviation was 3.0.

Keywords :Myasthenia gravis, Low rate repetitive stimulation test, Healthy adult, Control, Abductor digiti quinti