Somatosensory Evoked Potential(SEP) study was useful for the electrodiagnostic evaluation of the peripheral nerve, spinal cord and cerebral cortex.

SEPs were recorded on the Erb's point, C5 spinous process and scalp in response to median, ulnar and radial nerve stimulation at the wrist of 25 normal subjects.

The purpose of this study was to provide Korean standard value of upper limb short latency SEP. Following results were obtained.

1) The mean latencies of the N9, N13, N20 potentials were 9.62±0.53, 13.14±0.71, 19.06±0.88msec; 9.93±0.59, 13.93±0.96, 19.58±1.03msec; 10.81±0.87, 14.96±1.13, 20.87±1.17msec respectively in median, ulnar and radial SEPs.

2) The mean amplitudes of the N9, N13, N20 potentials were 5.03±2.25, 2.42±0.75, 6.57±2.61mV; 2.50±1.31, 1.30±0.58, 3.45±1.58mV; 1.18±0.50, 0.74±0.17, 2.34±1.31mV respectively in median, ulnar and radial SEPs.

3) There was significant correlation between the arm length and the latency, and between the height and the latency.