Chronotype Shifts and Cognitive Performance in Stroke Survivors: Exploring the Impact of Occupational Therapy Treatment Timing on Rehabilitation Outcomes.

Importance: Stroke survivors commonly report persistent sleep disruptions during rehabilitation and postrecovery. Despite little research that explores the impact of stroke on a patient's chronotype, no studies have explored the differences in cognitive performance between treatment timing fitted and nonfitted to the patient's chronotype.

Objective: To characterize the sleep chronotype in patients in the subacute poststroke period, to explore cognitive task performance differences during fitted and nonfitted hours, and to examine the relationships between sleep quality and cognitive performance.

Design: Cohort design.

Setting: Health care institution.

Participants: Twenty men and women (M  age = 60.2, SD = 8.6) post-first stroke.

Outcomes and measures: The following measures were collected twice, during fitted and nonfitted chronotypic times: demographic surveys, the Munich Chronotype Questionnaire, the Montreal Cognitive Assessment (MoCA), the Rivermead Behavioral Memory Test, Second Edition (RBMT-2), a fatigue questionnaire, and of actigraphy for 4 to 5 days.

Results: Stroke survivors exhibited an earlier sleep chronotype postinjury compared with preinjury. Enhanced memory (higher RBMT-2 scores) occurred during fitted hours. No significant differences emerged in executive functions, attention tasks, and MoCA scores between fitted and nonfitted hours. The Wake After Sleep Onset index correlated with the MoCA and RBMT-2 scores during fitted hours (MoCA: r = .53, p = .021; RBMT-2: r = .51, p = .027). Number of awakenings correlated with the MoCA letter task during nonfitted hours (r = .45; p = .044).

Conclusions and relevance: Occupational therapy practitioners should be aware of the relationship between chronotype and cognitive performance, with a focus on the importance of personalized rehabilitation strategies in stroke care. Plain-Language Summary: The timing of cognitive assessments poststroke can influence their reliability, particularly when considering a patient's chronotype (sleep cycle). For instance, if a morning person is evaluated later in the day (nonfitted to their chronotype), the results may indicate greater cognitive decline compared with scores they might achieve in the morning. In our study, we assessed cognitive performance twice: once fitted to the patient's chronotype and once not. Our findings revealed that memory function significantly improved during evaluations conducted at personalized times. This suggests that occupational therapy practitioners who evaluate patients during nonoptimal times may prescribe a more extensive rehabilitation plan than necessary.