Facilitation of Motor Evoked Potential by Stretching of Peripheral Nerve

ABSTRACT

OBJECTIVE: To investigate the effect of peripheral nerve stretching on motor evoked potentials (MEP) as a method of facilitation. METHODS: Twenty three normal healthy volunteers were enrolled. Transcranial magnetic stimu lation (TMS) was applied to the contralateral scalp at 7 cm lateral to Cz using 90 cm round coil. Intensity of stimulation was adjusted to 90% of maximal stimulation intensity. Recording was done on the abductor pollicis brevis muscle in three different conditions; firstly resting state, secondly voluntary contraction of abductor pollicis brevis muscle, and lastly with stretching of median nerve. The onset latency and amplitude were obtained and compared between three conditions. RESULT: The amplitude of MEP was significantly increased in the condition with muscle contraction and peripheal nerve stretching compared with resting state. The latency was shortened in the condition with muscle contraction with statistical significance and with peripheral nerve stretching without significance. CONCLUSION: We concluded that stretching of peripheral nerve can be used as a method of facilitation of MEP. This method is considered to be useful especially for the patients with motor paralysis or poor cooperarion for voluntary contraction.