Control of two simultaneous voluntary motor acts in normals and in parkinsonism.

BECAUSE of the multiple and varied aspects of Parkinsonism, the therapeutic approach has been exceedingly difficult. Most efforts have been directed toward symptomatic control of rigidity and tremor. The atropine-like drugs have been relatively successful in alleviating rigidity in patients able to tolerate adequate amounts.1Parsidol (10-[2-diethylamino-1-propyl] phenothiazine hydrochloride)2has been reasonably effective in some patients in reducing tremor, and by various drug combinations and the individualizing of dosages3many Parkinsonian patients continue to lead active, useful lives. A common complaint of the Parkinsonian patient is related, however, to fatigue and slowness in performing the chores of ordinary life. This is attributed to the interference caused by the muscle rigidity and tremor. In 50 patients with Parkinsonism, visual-motor reaction time tests have been routinely performed, and the values are close to normal in mild and moderately severe cases. In the course of observing a large number of