24 hour rest‐activity rhythms and cognition in community dwelling older adults

Abstract

AbstractBackgroundCognitive decline associated with aging is a growing public health concern as individuals are living longer with chronic medical conditions. Rest activity rhythm (RAR) describes the pattern of physical activity and sleep period in 24 hours. Compared with younger people, older adults are more likely to maintain a sedentary lifestyle with altered RAR. Although there is no doubt that physical activity plays a vital role in health outcomes, little is known about how RAR is linked to cognitive functioning in late life. This study investigated the association between RAR and cognitive performance among older adults.MethodSixty community dwelling older adults aged 70±7.3 years (mean ± standard deviation) wore Phillips actigraphy spectrum plus 2 for two weeks. RAR parameters were analyzed using cosinor approach, such as amplitude (difference between the peak and lowest activity levels), mesor (mean activity level), pseudo‐F‐statistic (the robustness of RAR), and acrophase (peak activity time). A comprehensive neuropsychological battery was used to assess cognition (i.e., Brief Visuospatial Memory Test – Revised (BVMT‐R), California Verbal Learning Test – II, Boston Naming Test, Wechsler Adult Intelligence Scale‐IV Coding, and Trail Making Test A and B). Multiple linear regression models were built to explore associations between different RAR measures and each cognitive task adjusting for age, gender, and years of education.ResultWe found positive associations between RAR amplitude (p = 0.01), mesor (p = 0.008), acrophase (p = 0.006), pseudo F‐statistic (p = 0.002) and visual memory (BVMT‐R). Similarly, positive associations were found between amplitude (p = 0.006), mesor (p = 0.005), acrophase (p = 0.005), pseudo F‐statistic (p = 0.002) and psychomotor processing speed (Coding). Greater pseudo‐F statistics were associated with stronger performance on naming (BNT); p = 0.03). No association was found between RAR and other cognitive tasks.ConclusionsOur findings provide evidence that some RAR characteristics are associated with cognitive performance among older adults, particularly visual memory, psychomotor processing speed, and naming ability. Further research should be undertaken using a large and diverse sample, prospective design, and inclusion of potentially confounding variables to confirm those associations.