title: Increased light exposure consolidates sleep and strengthens circadian rhythms in severe Alzheimer's disease patients.
abstract: 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.
authors.affiliation: 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
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.forename: Philip
authors.initials: P
authors.lastname: Gehrman
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Martin
authors.forename: Tamar
authors.initials: T
authors.lastname: Shochat
authors.forename: Matthew
authors.initials: M
authors.lastname: Marler
authors.forename: Jody
authors.initials: J
authors.lastname: Corey-Bloom
authors.forename: Leah
authors.initials: L
authors.lastname: Levi
mesh_terms: 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