Developing Optimal Focal Muscle Vibration for Improving Spasticity

The overall aim of the proposed study is to determine optimal parameter of focal muscle vibration for improving spasticity and identify neurophysiological mechanism in healthy subjects. In investigation I-1, subjects will undergo focal muscle vibration with 40, 80, 120 Hz frequency at the medial gastrocnemius muscles (mGCM). As a surrogate maker of spasticity, H-reflex and compound motor action potential (CMAP) of the tibial nerve at mGCM will be recorded pre, during, and post vibration. In investigation I-2, subjects will undergo focal muscle vibration with 0.1, 0.3, 0.5 mm amplitude at mGCM. H-reflex and CMAP of the tibial nerve at mGCM will be recorded pre, during, and post vibration. In investigation II, subjects will undergo focal muscle vibration with predetermined parameters by the investigation I at mGCM. H-reflex and CMAP of the tibial nerve and motor evoked potential at mGCM will be recorded pre, during, and post vibration.