Abstract NS17: REM Sleep is Moderately Associated With Off-line Motor Skill Learning in Individuals with Chronic Stroke

Abstract

Background: Sleep enhances motor skill learning in individuals with chronic stroke. However, the mechanisms underlying over-night (or off-line) motor skill enhancement remains unknown. Stage 2 non-REM and REM sleep have been associated with off-line motor skill learning in young adults. Therefore, we hypothesize that off-line motor skill learning in individuals with stroke will be positively correlated with time spent in stage 2 non-REM and REM sleep. Purpose: The purpose of this study was to assess which sleep parameters are associated with off-line motor skill learning in individuals with chronic (> 6 months) stroke. Methods: Eighteen individuals with chronic stroke underwent polysomnographic recording for three consecutive nights and practiced a continuous tracking (CT) task. The first night served as an acclimation night, and the second night served as a baseline night. The morning after the baseline night, participants practiced a CT task. Participants returned in the evening for polysomnographic recording. The following morning, participants performed a retention test of the CT task. Paired t-tests were used to assess improvement in tracking performance from the last practice block to the retention block. Pearson correlations were used to assess relationships between off-line motor skill learning and time spent in stage 2 non-REM and REM sleep. Results: Participants demonstrated an improvement in performance on the tracking task following a night of sleep as demonstrated by a significant reduction in tracking error from the last practice block to retention (t(17)=2.674, p=.016). Off-line learning was only weakly correlated with amount of time spent in stage 2 non-REM sleep (r= .123), but was moderately correlated with amount of time spent in REM sleep (r= .368). Conclusion: This study is the first to find that off-line motor skill learning is weakly associated with time spent in stage 2 non-REM sleep, but is moderately related to time spent in REM sleep for individuals with chronic stroke. In conclusion, sleep is a factor that should be considered when treating individuals following stroke. Future studies should determine if enhancing REM sleep pharmacologically would improve motor skill learning and potentially impact recovery following stroke.