Remediation of the Non-Paretic Arm in Stroke

The investigators previously elaborated hemisphere specific motor deficits in the non-paretic arm of chronic stroke survivors with unilateral hemisphere damage. The investigators showed that these deficits are associated with substantial limitations in performance of activities of daily living (ADL), an effect exacerbated by contralesional paresis due to forced reliance on the non-paretic arm. The investigators now hypothesize that the combination low moderate to severe paresis (Fugl-Meyer Score \< 35) and persistent motor deficits in the non-paretic arm limits functional independence in chronic stroke survivors. The investigators predict that intense remediation focused on improving the speed, coordination, and accuracy of the non-paretic arm should improve functional independence, as well as improving paretic arm function due to increased participation in daily activities. Unfortunately, the usual standard of care in rehabilitation for survivors with low-moderate to severe paresis tends to focus on task training in essential ADL activities, rather than on intensive remediation. Previous research has shown that non-paretic arm deficits depend on the hemisphere that is damaged by stroke, such that left hemisphere damage (LHD) impairs trajectory features, including speed and smoothness, while right hemisphere damage (RHD) impairs the ability to bring the arm to rest at an accurate and stable position. The investigators have designed a training program to address both of these motor components and to improve the speed and dexterity of the non-paretic arm. The investigators propose a randomized study design with two tracts, two periods and four assessments. Participants will first complete 2 baseline assessments, spaced 3 weeks apart. Following completion of the second assessment, participants will be randomly assigned to one of two tracks: Track 1 will receive three weeks of arm training, followed by 3 weeks of a comparison condition. Participants assigned to track 2 will receive three weeks of the comparison condition, followed by 3 weeks of arm training. Then, all participants will complete an end-of-period assessment, and a follow-up assessment for retention, 3 weeks after completion of the two periods. Pilot results indicate that non-paretic arm training produces substantial improvements in motor performance and functional independence as well as reducing paretic arm impairment. This is an essential first-step in developing a rehabilitation protocol focused on remediating both arms of severely impaired stroke survivors.