Within and between person effects of sleep quality on daily cognitive performance: Data from the Einstein Aging Study (EAS)

Abstract

AbstractBackgroundEvidence suggests that sleep disturbance may precede cognitive decline and may thus be a target for early intervention. Few studies have examined the short term (day to day) associations between sleep quality and cognitive performance in older adults. The Einstein Aging Study (EAS) provided the opportunity to examine ambulatory measures of sleep (actigraphy) and smartphone based ecological momentary assessments of cognitive performance to examine between‐ and within‐person effects of sleep quality on cognitive performance the following day.MethodsAnalyses involved 224 participants enrolled in the Einstein Aging Study, a community based longitudinal cohort of older adults free of dementia at enrollment (Mean age 77.3 years; 33% male; 47% White, 39% African American, 13% Hispanic). Participants wore an actiwatch, and completed brief smartphone based cognitive assessments 6 times per day over an 18‐day period. Multilevel models were used to examine between‐person and within‐person associations between objective measures of sleep quality (wake after sleep onset (WASO)), and duration with daily mean cognitive performance, adjusted for age, gender, race/ethnicity, education (years), and learning effects. Cognitive performance was assessed using previously validated smartphone based cognitive tests of processing speed (Symbol Match), working memory (Color Dot) and memory binding (Color Shape).ResultsBetween person results show that older adults with less nightly WASO on average had better processing speed (b=7.18, p=0.001), better working memory (b=0.001, p=0.005), and better memory binding (b= ‐0.003, p<0.001). Within‐person results showed that higher WASO was significantly associated with worse processing speed the next day: A thirty‐minute increase in nightly WASO predicted a 13 millisecond increased response time on the Symbol Match Test (p=0.001). There were no significant within‐person associations between WASO and working memory or memory binding. Sleep duration was not associated with cognitive performance in any of the analyses.ConclusionsWithin individuals, poor sleep quality is associated with worse cognitive processing speed the following day. The cumulative effects of poor sleep may lead to long term cognitive decline. Future work will determine whether individuals susceptible to the adverse effects of sleep from day to day are at increased risk for long term cognitive decline.