Responses of the densely hemiplegic upper extremity to bilateral training

Recovery of movement in the densely hemiplegic upper extremity remains a problem after stroke. This study aimed to determine whether movement recovery could be improved in the hemiplegic arm with bilateral isokinematic training.

Within and between groups, planned comparisons investigated the effects of bilateral training on attempts at two movements by subjects with acute and chronic problems with one and two bilateral practice phases. Electromyographic (EMG) activity of middle deltoid and extensor carpi radialis longus in the hemiplegic arm was recorded during unilateral and bilateral isometric shoulder abduction and wrist extension.

Small increases in muscle activity were demonstrated by both experimental and control subjects during most bilateral practices in both actions. However, these increases were not significantly different from the previous unilateral trial, and the bilateral effect failed to generalize to subsequent trials. Previous studies with less densely hemiplegic subjects had demonstrated generalization of improvements in movement patterns with bilateral training to unimanual actions of the densely hemiplegic arm.

Extensive lesions may limit brain reorganization and recover of dense hemiplegia after stroke. Nonetheless, on the basis of findings from other studies in which functional improvements occurred in both acute and chronic severely stroke-affected subjects, outcome forecasting for the hemiplegic upper extremity should only eventuate after provision of practice under optimal learning conditions.