Reaction Time in Parkinson's Disease

Both reaction time and movement time tend to be prolonged in Parkinson's disease, but they are often impaired independently of each other. Prolongation of RT is relatively slight, while MT undergoes more substantial and consistent disturbance. Choice RT and kinaesthetic RT do not have any advantage over simple visual RT as measurements of neurological deficit in parkinsonism, since they are all impaired to the same extent. MT is more useful than RT as an objective indicator of therapeutic efficacy, but further studies of RT (with tests requiring programming of displacement, velocity, and accuracy) may provide insights into the nature of the central motor disorder in Parkinson's disease.