Does sleep matter for recovery after stroke? Functional severity shapes the association between sleep and functional outcome during inpatient stroke rehabilitation

Background Sleep disturbances are common after stroke and have been associated with rehabilitation outcomes. The clinical meaning of post-stroke sleep duration remains unclear, as longer sleep may be associated with different clinical and functional states, including greater disability. This exploratory study investigated the relationship between sleep and functional outcome during stroke rehabilitation, and the moderating role of baseline functional status. Methods Twenty-nine patients with stroke underwent a 10-day longitudinal monitoring protocol during rehabilitation. Functional independence and motor performance were assessed at the beginning (T0) and the end (T1) of the observation period using the Barthel Index, 10-Meter Walk Test, and 9-Hole Peg Test. Sleep was assessed throughout the monitoring period using sleep diaries, and actigraphy . Results Functional independence improved from T0 to T1, whereas motor performance did not significantly change. In unadjusted analyses, longer actigraphy-derived total sleep time and longer self-reported total time in bed were correlated with lower Barthel Index scores at T1. Moderation analyses adjusted for prior rehabilitation days showed that longer total sleep time was positively associated with Barthel Index at T1 only in patients with higher baseline independence, while longer time in bed was positively associated at average and higher baseline levels. Conclusions The associations between sleep duration or time in bed and later post-rehabilitation functional independence vary according to baseline functional status. Given the small sample size and observational design, these findings should be interpreted cautiously and considered preliminary and hypothesis-generating