Objective assessment of sleep and sleep problems in older adults with intellectual disabilities.

Little is known about sleep in older adults with intellectual disability (ID). Aim of this study was to investigate sleep and its associated factors, and to estimate the prevalence of sleep problems in this population. This study was part of the healthy aging and intellectual disabilities study. Sleep was assessed using the Actiwatch, a watch-like device that measures sleep and wakefulness based on movement activity. Participants (n=551) wore the Actiwatch at least seven days and nights continuously. Variables of interest were time in bed (TIB), sleep onset latency, total sleep time, wake after sleep onset, sleep efficiency and get-up time latency. Multivariate analyses were used to investigate factors associated with these sleep parameters. Provisional definitions were drafted to estimate the prevalence of sleep problems. Mean TIB was 630 min. Longer TIB was independently associated with higher age, more severe level of ID, living at a central facility, wheelchair dependence, female gender and depressive symptoms (adjusted R(2)=.358, F-change=8.302, p<.001). The prevalence of sleep problems was 23.9% settling problem, 63.1% night waking problem, 20.9% short sleep time, 9.3% early waking problem. 72% of the participants had at least one problem, 12.3% had three or more sleep problems. Older adults with ID lie in bed very long, and the prevalence of sleep problems is high. Further research should focus on causality of the relationships found in this study, and effects of sleep problems on health and well-being in this population.