Introduction: Sleep-wake disturbances can exacerbate delirium and cognitive impairment in older adults recovering from critical illness. Advancements in wearable sleep technology provide innovative opportunities for understanding relationships between sleep quality and cognitive function. Leveraging portable polysomnography and actigraphy, we explored associations between nighttime sleep architecture, nighttime activity, and working memory in older adult intensive care unit (ICU) survivors. Methods: We analyzed data from a subset of 11 English- or Spanish-speaking older adult ICU survivors (mean age: 75.7 ± 6.3 years) who consented to wearable sleep technology after ICU discharge to a post-ICU unit. Portable polysomnography measured time spent in each sleep stage (NREM sleep stages N1, N2, and N3; and REM sleep), and wrist actigraphy measured nighttime activity (activity counts/minute) over two consecutive nights (10:00 PM to 06:00 AM). Working memory was assessed using the National Institutes of Health (NIH) Toolbox Cognition Battery List Sorting Test fully-corrected T score. Selected covariates included patient-reported symptoms of sleep and cognitive function, as assessed by Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep-Related Impairment and Cognitive Function T scores. Multiple regression models examined associations between nighttime sleep, nighttime activity, and working memory with adjustment for covariates. Results: Greater time spent in NREM sleep stages (β = 0.58, p =.03) and less sleep-related impairment (β = -0.881, p =.019) were associated with better working memory scores (R2 =.688, p =.035). Higher nighttime activity counts (β = -0.582, p =.043) were associated with worse working memory scores (R2 =.657, p =.047). Conclusions: Our findings suggest that preserving deeper stages of sleep and minimizing nighttime disturbances may be potentially modifiable targets to support cognitive recovery after critical illness. Wearable sleep technology could facilitate early identification of older adult ICU survivors at risk for cognitive decline and enable the development of personalized clinical interventions. Future studies are warranted to test the efficacy of sleep promotion interventions on long-term cognitive outcomes in this complex population.
Elias et al. (Sun,) studied this question.