HOURLY PROFILES OF SLEEP AND WAKEFULNESS IN SEVERELY VERSUS MILD-MODERATELY DEMENTED NURSING-HOME PATIENTS

The purpose of the current study was to examine differences in hour-by -hour sleep/wakefulness profiles between severely and mild-moderately demented patients, and to assess hour many elderly patients remain alm ost fully asleep or nearly fully awake in each hour of a 24-hour perio d. Sleep/wakefulness patterns of 67 demented nursing home residents (m ean age=85.7 years) were recorded using Actillume recorders. One 24-ho ur period was used, and numbers of minutes spent asleep or awake were computed for every hour. There were 46 severely demented patients, and 21 mild-moderately demented patients. The amount of sleep and wakeful ness recorded for each hour was compared between the two groups. In ad dition, the frequencies of patients who remained asleep for more than 90% of each hour, and of those who sustained wakefulness for move than 90% of each hour were computed for every hour, and comparisons were a gain made between the two groups. Multivariate analysis of variance sh owed a significant effect of dementia group on the percent of sleep/wa kefulness over 24 hours (p=0.028). Subsequent t-tests performed separa tely for each hour revealed significant differences between the two de mentia groups in 13 out of the 24 hours. Significant differences in th e frequencies of patients asleep >90% or awake >90% of each hour were centered around the early night and early morning hours. Patients with mild-moderate dementia showed a disproportionate amount of wakefulnes s during the night, whereas, in addition, patients with severe dementi a showed a disproportionate amount of sleepiness during the day With t he progression of dementia, both the capacity to maintain sleep and th e capacity to maintain wakefulness are impaired, and result in complet e fragmentation of sleep/wakefulness during the night and day. (Aging Clin. Exp. Res. 10: 308-315, 1998) (C) 1998, Editrice Kurtis.