Timing of sleep and wakefulness in Alzheimer's disease patients residing at home

Dysfunction of the circadian timing system has long been suspected in Alzheimer's d i ~ (AD) because such patients frequently, though not inevitably, have sleep disturbance (Bliwise 1989). Despite such sleep disruption, some studies of various physiological phenomena typically showing diurnal variation (e.g., body temperature, cortisol, prolactin, melatonin) have had difficulty showing differences between AD patients and controls (Prinz et al 1984; Touitou 1982; Christie et al 1983), perhaps owing to selection bias in patients studied (Witting et al 1990). More recently, Campbell et al (1988) reported the existence of an earlier acrophase in the body temperature cycle in male AD patients relative to age-matched, nondemented controls. This finding contrasts with the data of Satlin et al (1991) who reported a delayed acrophase in the rest/activity cycle in AD patients. Here we present data on the timing of sleep/wakefulness in AD patients in their home as recorded by caregivers in a l-week sleep log. To the best of our knowledge, no data currently exist on the timing of sleep and wakefulness in a group of well-characterized AD patients in their natural environments. Methods