| Abstract: | ![]()
Agitation is a common problem in institutionalized patientswith Alzheimer's disease (AD). “Sundowning,” or agitationthat occurs primarily in the evening, is estimated to occur in 10—25%of nursing home patients. The current study examined circadian patterns ofagitation in 85 patients with AD living in nursing homes in the San Diego,California, area. Agitation was assessed using behavioral ratings collectedevery 15 minutes over 3 days, and activity and light exposure data were collectedcontinuously using Actillume recorders. A five-parameter extension of thetraditional cosine function was used to describe the circadian rhythms. Themean acrophase for agitation was 14:38, although there was considerable variabilityin the agitation rhythms displayed by the patients. Agitation rhythms weremore robust than activity rhythms. Surprisingly, only 2 patients (2.4%) were“sundowners.”In general, patients were exposed to very low levelsof illumination, with higher illumination during the night being associatedwith less robust agitation rhythms with higher rhythm minima (i.e., some agitationpresent throughout the day and night). Seasonality was examined; however,there were no consistent seasonal patterns found. This is the largest studyto date to examine agitation rhythms using behavioral observations over multiple24h periods. The results suggest that, although sundowning is uncommon, agitationappears to have a strong circadian component in most patients that is relatedto light exposure, sleep, and medication use. Further research into the understandingof agitation rhythms is needed to examine the potential effects of interventionstargeting sleep and circadian rhythms. (ChronobiologyInternational, 17(3), 405–418, 2000) |
