TEMPORAL SHIFTS IN PEAK DAILY ACTIVITY IN ALZHEIMERS-DISEASE

Clinicians caring for Alzheimer patients have observed that some indiv iduals show increased agitation, restlessness and confusion in the lat e afternoon, evening or at night. This has popularly been named 'sundo wning' or 'the sundowning syndrome'. Despite its obvious clinical impo rtance, little research has been conducted to investigate abnormal act ivity patterns in patients with Alzheimer's disease. In this study, re st-activity patterns were examined using an electronic monitor with a movement sensor. Eighteen patients diagnosed with Alzheimer's disease were monitored for 48 consecutive hours each. Analyses indicated that some subjects showed increased activity around the time of sunset, and that these individuals were most likely to be in the middle stages of the disease. Subjects in the early stages of the disease showed peak activity before sunset, while those in the late stage showed peak acti vity after sunset. This progressive phase shift with increasing years of illness is a previously unreported phenomenon which may offer an ex planation for the 'sundowning syndrome'.