Basta M, et al. - In people with mild cognitive impairment (MCI), researchers studied the connection between objective sleep and cognitive performance. From a large population-based cohort (aged > 60 years), they recruited a subsample of 271 participants with a diagnosis of probable Alzheimer's disease (AD; N=50) or MCI (N=121) and 100 individuals who were not cognitively impaired (NI). All study participants completed extensive neuropsychiatric/neuropsychological evaluation, as well as a 3-day, 24-hour actigraphy. Compared with the MCI and NI groups, patients with AD had significantly longer 24-hour total sleep time (TST). Long 24-hour TST was related to reduced performance on tasks that placed significant demands on those in the MCI group and the AD group on attention and processing speed. Elderly MCI patients had the same objective duration of sleep as normal controls, while AD patients slept longer. Long sleep duration was associated with critical non-memory cognitive domains in patients with MCI multidomain subtypes. Those who sleep longer may have more severe cognitive impairment within the MCI group, according to findings.