Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 50, Issue 6 M303-M306, Copyright © 1995 by The Gerontological Society of America
Observed sleep/wakefulness and severity of dementia in an Alzheimer's disease special care unit
DL Bliwise, M Hughes, PM McMahon and N Kutner
Sleep Disorders Center, Emory University Medical School, USA.
BACKGROUND. This study tested the hypothesis that behaviorally defined
sleep disturbance among residents in a Special Care Unit (SCU) for
Alzheimer's disease (AD) was related to the severity of their dementia.
Previously, sleep laboratory studies have reported such relationships when
sleep has been recorded polysomnographically over several nights.
Observational studies of sleep have not shown such relationships,
presumably because of the impression involved in determining sleep/wake
state behaviorally. METHODS. Nightly sleep data based on observations made
every two hours by nursing staff for a period of 13 to 18 months were
examined for 47 AD residents with a mean age of 80.7 +/- 6.5 years. Level
of dementia and functional capacity were assessed with the Mattis Dementia
Rating Scale (DRS) and the Katz Activities of Daily Living Scale (ADL).
RESULTS. Data indicated that these SCU residents experienced a moderately
disturbed night of sleep an average of 24% +/- 10% of their nights in the
facility and a severely disturbed night of sleep on 7% +/- 6% of those
nights. More profound dementia was associated with more sleep disturbance;
however, incapacity in ADLs, age, gender, and psychoactive medications were
unrelated to such disturbances. CONCLUSIONS. The results indicate that
patterns of relationships noted between laboratory-based measures of sleep
and variables such as severity of dementia can be detected using behavioral
observations of sleep, provided that the number of nights of observation
are sufficiently large to offset the measurement error involved in their
use.
