Sleep Regularity Index After Stroke: Change Over Time and Its Association With Recovery: A Longitudinal Observational Study.

Sleep-wake disruption is common after stroke and may impede recovery. The Sleep Regularity Index (SRI) quantifies the probability that an individual is in the same sleep or wake state at the same clock time on consecutive days. This study evaluates SRI during poststroke recovery, estimating associations with stroke outcomes and characterizing transitions between SRI states over time. We analyzed data from 71 participants who were part of a larger ongoing study exploring the impact of nonobstructive sleep apnea sleep disorders post stroke. Data were collected at 10, 60, and 90 days post stroke. SRI was calculated from sleep-wake data that were collected from wrist-worn actigraphy. Covariates included time, sex, stroke location, modified Rankin Scale score, Stroke Impact Scale score, Patient Health Questionnaire 9 score, and oxygen desaturation index. Associations between SRI and covariates were estimated using generalized estimating equations models. A generalized estimating equations model was also used to assess which variables may be associated with SRI improvement. SRI was low at 10 days post stroke (32.68) and did not significantly change at 60 (34.01, P=0.41) or 90 (38.44, P=0.42) days post stroke. SRI was significantly associated with Patient Health Questionnaire 9 (P=0.05) and Stroke Impact Scale (P=0.04) scores. Only initial SRI was associated with improvement in SRI. This is the first study that we are aware of to investigate sleep regularity early after stroke. We found that sleep regularity was associated with depression and quality of life and that sleep regularity did not improve after discharge from the hospital. URL: https://www.clinicaltrials.gov; Unique identifier: NCT05012605.