The Neurophysiologic Response of Anterior Horn Cell Activity to Paraspinal Electrical Stimulation

ABSTRACT

OBJECTIVE: This study was proposed to evaluate the electrophysiologic changes in central motor conduction and in silent period (SP) after paraspinal transcutaneous electrical stimulation near caudal area of the spinal cord. METHOD: Conditioning stimulation was applied to T12 paraspinal area for 20 minutes using interferential current therapy (80~100 Hz) in 11 healthy subjects. The amplitude and latency of central motor conduction and duration of SP were measured in motor evoked potential (MEPs) by using magnetic stimulator, before and after the conditioning stimulation. These variables were recorded in both tibialis anterior muscle, innervated from stimulated spinal area, and both abductor pollicis brevis, innervated from cervical cord not directly stimulated by electrical stimulation. RESULTS: After conditioning stimulation, the amplitudes of central motor conduction decreased (p<0.01), and the latencies did not change in both cervical and lumbar muscles in transcranial and spinal MEP studies, and the duration of SP was decreased in same manner (p<0.01). CONCLUSION: These results mean that the excitability of anterior horn cells decreases and the supraspinal inhibitory mechanism of the central motor conduction is suppressed by a certain conditioned electrical cutaneous stimulation in entire spinal cord.