Increased light exposure consolidates sleep and strengthens circadian rhythms in severe Alzheimer's disease patients.
Sleep in the nursing home environment is extremely fragmented, possibly in part as a result of decreased light exposure. This study examined the effect of light on sleep and circadian activity rhythms in patients with probable or possible Alzheimer's disease. Results showed that both morning and evening bright light resulted in more consolidated sleep at night, as measured with wrist actigraphy. Evening light also increased the quality of the circadian activity rhythm, as measured by a 5-parameter extended cosine model (amplitude, acrophase, nadir, slope of the curve, and relative width of the peak and trough). Increasing light exposure throughout the day and evening is likely to have the most beneficial effect on sleep and on circadian rhythms in patients with dementia. It would behoove nursing homes to consider increasing ambient light in multipurpose rooms where patients often spend much of their days.
Ancoli-Israel
Sonia
S
Department of Psychiatry 116A, University of California, Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Drive, San Diego, CA 92161, USA. sancoliisrael@ucsd.edu
Gehrman
Philip
P
Martin
Jennifer L
JL
Shochat
Tamar
T
Marler
Matthew
M
Corey-Bloom
Jody
J
Levi
Leah
L
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology*; D021081:Chronobiology Disorders / Q000453:epidemiology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010789:Phototherapy / Q000379:methods*; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology