Abstract
The distances of body sway of seven Parkinsonian patients were measured after the vibration stimulus on triceps suraes. Results obtained were; 1) no significant difference in the distance of body sway was observed between Parkinsonian patients and controls, and 2) the time required for the center of the gravity returning to the previous position before the stimulus became shorter with a smaller amplitude of body sway after the stimulus. These results suggested that the cerebrum, the cerebellum, and reflex system as well as visual input may play an important role in controlling external stimuli to triceps suraes.