Abstract
BACKGROUND: The ability to relearn a lost skill is critical to motor recovery after a stroke. Previous studies indicate that stroke typically affects the processes underlying motor control and execution but not the learning of those skills. However, these prior studies could have been confounded by the presence of significant motor impairments and/or have not focused on motor acuity tasks (i.e., tasks focusing on the quality of executed actions) that have direct functional relevance to rehabilitation. METHODS: Twenty-five participants (10 stroke; 15 controls) were recruited for this prospective, case-control study. Participants learned a novel foot-trajectory tracking task on two consecutive days while walking on a treadmill. On day 1, participants learned a new gait pattern by performing a task that necessitated greater hip and knee flexion during the swing phase of the gait. On day 2, participants repeated the task with their training leg to test retention. An average tracking error was computed to determine online and offline learning and was compared between stroke survivors and uninjured controls. RESULTS: Stroke survivors were able to improve their tracking performance on the first day (p=0.033); however, the amount of learning in stroke survivors was lower in comparison with the control group on both days (p≤0.05). Interestingly, the offline gains in motor learning were higher in stroke survivors when compared with uninjured controls (p=0.011). CONCLUSIONS: The results suggest that even high-functioning stroke survivors may have difficulty acquiring new motor skills related to walking, which may be related to the underlying neural damage caused at the time of stroke. Furthermore, it is likely that stroke survivors may require longer training with adequate rest to acquire new motor skills, and rehabilitation programs should target motor skill learning to improve outcomes after stroke.