Sleep well, think well: sleep-wake disturbance in mild cognitive impairment

While literature suggests that sleep is important for cognition and mood, and that sleep disturbance is a prominent feature of neurodegenerative and neuropsychiatric disorders, these relationships have not yet been examined in older people ''at risk" of dementia. In this study, 15 older people with the nonamnestic subtype of mild cognitive impairment ([MCI] mean age = 66.7 years, SD = 8.7) underwent psychiatric and neuropsychological assessment. Participants completed sleep diaries, questionnaires, and 2 weeks of actigraphy. Key outcome data during the rest interval were time spent ''awake" or wake after sleep onset (WASO) and the number of arousals/wake bouts. Results showed that even after controlling for age, greater WASO was associated with reduced attention and executive functioning and increased arousals were related to poorer nonverbal learning and problem solving. This preliminary data suggests that sleep-wake disturbance in nonamnestic forms of MCI is related to cognitive functioning and may be indicative of shared neurobiological underpinnings.