Coordination of aimed movements in a case of unilateral cerebellar damage.

We have studied multi-joint arm movements in a patient with right cerebellar damage. Our patient's kinetic tremor was reduced in the absence of visual feedback, but increased when performing a concurrent cognitive task. We suggest that her kinetic tremor reflects use of a slow cortical feedback circuit for error-corrections during movement. Analysing the spatial relation between hand aperture and hand transport in prehensile movements, we found preserved strategic, trial-to-trial coordination, but impaired reactive, within-trial coordination. We conclude that the proprioceptive representations provided by the normal cerebellum play an important role in coordinating multi-joint movement.