Assessing sleep metrics in stroke survivors: a comparison between objective and subjective measures

Introduction: Stroke survivors are at risk of sleep disturbance, which can be reflected in discrepancies between objective and subjective sleep measures. Given there are limited studies on this phenomenon and using portable monitoring devices is more convenient for stroke survivors to monitor their sleep, this study aimed to compare objectively measured (Belun Ring) and subjectively reported (sleep diary) sleep metrics (total sleep time (TST) and wakefulness after sleep onset (WASO)) in stroke survivors.

Methods: In this cross-sectional study, thirty-five participants wore a ring-shaped pulse oximeter (Belun Ring) and kept a sleep diary for three consecutive nights in one week. The effects of various factors on TST and WASO were analyzed by linear mixed models. Systematic bias between two measures was examined by the Bland-Altman analysis.

Results: TST and WASO were significantly affected by measures (p <.001), but not night. TST was significantly lower and WASO was significantly higher in the Belun Ring than in the sleep diary (p <.05). Age was the only covariate that had a significant effect on WASO (p <.05). The Bland-Altman analysis demonstrated positive bias in TST (29.55%; 95% CI [16.57%, 42.53%]) and negative bias in WASO (-117.35%; 95% CI [-137.65%, -97.06%]). Proportional bias was exhibited in WASO only (r =.31, p <.05).

Conclusion: The findings revealed discrepancies between objective and subjective sleep measures in stroke survivors. It is recommended that objective measures be included when assessing and monitoring their sleep conditions.