Motor learning after unilateral brain damage

Forty adults, post-stroke from anterior circulation unilateral cerebrovascular accident(∼2 years post onset) and 40 age-matched controls ( M = 57 years) practiced a rapid,spatially and temporally constrained programmed action under one of two augmented feedbackpractice conditions. Participants in the stroke group used the upper limb ipsilateral to the lesion.After an extended practice period (198 trials), acquisition, retention, and reacquisitionperformance was assessed for accuracy and consistency and compared over trials, betweengroups and feedback conditions. Both stroke and control groups demonstrated significantimprovement in accuracy and consistency over practice with relative persistence of these changesduring retention. There were no differences between groups (stroke vs control) in performancepatterns across trials for acquisition, retention, or reacquisition phases. In addition, there were nodifferential effects of the two augmented feedback conditions on performance and no interactionsof feedback condition with group. However, independent of feedback condition, the stroke groupperformed with more error than did the control group during all experimental phases (i.e.,acquisition, retention, reacquisition). These results suggest that unilateral stroke-related damagein the sensorimotor areas primarily effects the processes underlying the control and execution of motor skills but not the learning of those skills. Implications of thesefindings for physical rehabilitation are discussed.