The role of cortical and subcortical mechanisms in voluntary movement in Parkinson's disease. An electrophysiological study.
Voluntary responses to peripheral stimulation in 12 normal subjects and 12 parkinsonian patients in the same age group were examined electromyographically. The successive reaction (SR) times (interval between two quick repetitive voluntary movements)  of the arm flexors and extensors, as well as the head flexors and extensors and the foot flexors and extensors, in the normal subjects were compared with those in the parkinsonian patients. The study was carried out in order to find out whether there are differences in the cortical responses to successive voluntary movements from different areas of the periphery, and to try to explain clinical phenomena such as the gait difficulties (marche á petit pas), the poor arm swing when walking and the early forward head inclination of the parkinsonian. The voluntary responses of the parkinsonian patients revealed significant prolonged SR times in all examined muscles, but especially following voluntary muscle activity of the foot flexors and extensors. These results suggest that the cortical inhibition after peripheral voluntary response is not uniform in all muscle groups and perhaps reflects selective inhibitory mechanisms via the motor cortex.
D002540:Cerebral Cortex / Q000503:physiopathology*; D004576:Electromyography; D006801:Humans; D009068:Movement; D010300:Parkinson Disease / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology