Motor learning after unilateral brain damage

Forty adults, post-stroke from anterior circulation unilateral cerebrovascu lar accident (similar to 2 years post onset) and 40 age-matched controls (M = 57 years) practiced a rapid, spatially and temporally constrained progra mmed action under one of two augmented feedback practice conditions. Partic ipants in the stroke group used the upper limb ipsilateral to the lesion. A fter an extended practice period (198 trials), acquisition, retention, and reacquisition performance was assessed for accuracy and consistency and com pared over trials, between groups and feedback conditions. Both stroke and control groups demonstrated significant improvement in accuracy and consist ency over practice with relative persistence of these changes during retent ion. There were no differences between groups (stroke vs control) in perfor mance patterns across trials for acquisition, retention, or reacquisition p hases. In addition, there were no differential effects of the two augmented feedback conditions on performance and no interactions of feedback conditi on with group. However, independent of feedback condition, the stroke group performed with more error than did the control group during all experiment al phases (i.e., acquisition, retention, reacquisition). These results sugg est that unilateral stroke-related damage in the sensorimotor areas primari ly effects the processes underlying the control and execution of motor skil ls but not the learning of those skills. Implications of these findings for physical rehabilitation are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.