It has been reported that electrical stimulation of nerves brings about changes of the anterior horn cell excitability and the nerve conduction in vivo and in vitro. The purpose of this study is to evaluate the electrophysiologic changes by 90-100Hz electrical stimulation of distal peripheral nerves. The conditioning stimulation was applied to 20 healthy subjects that was the interferential current of 90-100 Hz frequency under the maximal tolerable intensity(average 30mA). The site of conditioning stimulation was the distal tibial and peroneal nerves of one foot. Before and after conditioning stimulation, we investigated the peripheral nerve conduction, the H reflex, the F wave, and the somatosensory evoked potential(SEP) of the ipsilateral tibial nerve proximal to the conditioned site. The latency of tibial motor conduction, the latency of H reflex, the duration of F wave, and the P1 latency of tibial nerve SEP were increased significantly(P<0.05), and the F ratio was decreased(P<0.05) by the conditioning stimulation. The amplitude and the duration of tibial motor conduction, the amplitude of H reflex, the H/M ratio, the duration and the conduction velocity and time of the F wave, the P1N1 amplitude of tibial nerve SEP, and the latency of sural and postrior femoral cutaneous sensory conduction were not changed by conditioning stimulation. These results suggest that certain conditioned electrical stimulation of distal peripheral nerves can bring about the inhibitory effect to the alpha motor fiber conduction and to the conduction related with sensory activity in the spinal cord.

Keywords :Electrical stimulation, H reflex, F wave, Somatosensory evoked potential, Peripheral nerve conduction