In order to investigate the significance of somatosensory evoked potential test in the evaluation of recovery of peripheral nerve lesions and to establish the recovering pattern of somatosensory evoked potential test in peripheral nerve lesions, we analyzed forty-two patients with peripheral nerve lesions by sensory nerve conduction study, motor nerve conduction study, electromyography (EMG) and somatosensory evoked potentials (SEP) from the scalp overlying the contralateral somatosensory cortex in response to electrical stimulation of peripheral nerves. SEPs of peripheral nerves were classified according to the various methods to predict the outcome and to evaluated the relationship of patterns of SEP and regeneration state of injured nerves.

In the prediction of outcome of neurological recovery, most helpful method was needle EMG and in the order of SEP, motor nerve conduction study and sensory nerve conduction study respectively. There was a good correlation between the neurological recovery and the presence or absence of SEP (P<0.005) within three months after the injury. Among the classification methods of SEP, the grades of second method and third method correlated better with the state of regeneration of peripheral nerves than that of first method.

It is suggested that SEPs from the peripheral nerves when interpreted in combination with conventional EMG may give useful additional information about the state of regeneration and the prediction of outcome in the patients with peripheral nerve lesions.