Effect of L-Dopa on Electromyograph and Heart Rate of Parkinsonians

Abstract

Electromyograph (EMG) and heart-rate recordings were taken from 17 parkinsonians before administration of L-Dopa and from 17 equated parkinsonians after a mean of 6.8 mo. of drug administration. Right and left EMGs were recorded by means of surface electrodes from the sternocleidomastoid muscles of the neck. Right EMG ratings, based primarily upon amplitude, were significantly lower for post-L-Dopa group than for pre-L-Dopa group; no significant difference between pre- and post-L-Dopa groups was found with respect to left EMG. No significant difference in heart rare was found between pre- and post-L-Dopa groups. It is suggested that the drug may differentially affect left-hemisphere functions. An explanation was proposed utilizing concepts of behavioral activation.