Effects of practice and unpredictable distractors on planning and executing aiming after stroke.

The primary purpose of this study was to examine practice effects on the planning and execution of an aiming movement after right versus left stroke. A secondary purpose was to investigate the effects of a distractor that appeared randomly on motor performance after stroke. Right-hand dominant individuals, 15 with right stroke (right-sided brain damage), 16 with left stroke, and 30 without stroke, performed aiming movements to targets. Those with stroke used the ipsilesional upper extremity (UE). Right and left comparison groups used the right and left UE, respectively. Reaction time (RT) and movement time (MT) were collected to represent movement planning and execution, respectively. Individuals with right stroke improved RT with practice. Individuals with left stroke did not improve RT with practice and made more errors than their comparison group. Those with left stroke achieved faster MT with practice, but MT remained slower than their comparison group. There were no effects of the distractor on RT or MT. Adults with left stroke have persistent deficits in movement planning and execution. Further studies are needed to determine how the performance of older adults, with or without stroke, is affected by an unpredictable visual distractor.