Disturbances of sleep and cognitive functioning in patients with dementia

The relationship of sleep, circadian rhythms, and cognitive impairment in dementia patients is briefly reviewed. All-night sleep EEG data were collected in relatively young and relatively unimpaired patients with presumptive Alzheimer's disease and eight age-matched controls. Delta sleep time and Delta sleep % (Stages 3 and 4)--but not REM sleep measures--were significantly reduced in the patients. Implications of these findings are discussed.