Recovery of voluntary movement in hemiplegic patients. Correlation with degenerative shrinkage of the cerebral peduncles in CT images.

The severity of the disorder of voluntary movement in 89 chronic hemiparetic patients was correlated with the degenerative reduction of descending fibres evaluated by the magnitude of the shrinkage of the cerebral peduncles (CP) in computed tomographic (CT) images. The severity of hemiplegic posture and motor disturbance in the proximal and distal muscles was related to the total amount of residual descending fibres in the CP. In all patients whose CPs were less than 60% of the normal size, recovery from disturbance in reaching and grasping movements and impairment of relative independent finger movements was incomplete. Recovery of these movements occurred when more than 60% of the CP was spared and the degree of recovery from motor weakness was positively correlated with the quantity of intact fibres spared (residual CP ratio). The ability to perform fine and discrete movements with the fingers, known to be an essential function of the pyramidal system, was consistently impaired in patients with severe shrinkage involving the medial division of the CP. There was no particular correlation between the CP shrinkage and neurological signs such as spasticity, hyperreflexia, and pathological reflexes.