Effect of light on sleep and circadian rhythms in demented nursing home patients
Journal of the American Geriatric Society (2002)
January 1, 2002
Ancoli-Israel S, Martin JL, Kripke DF et al.
Sleep fragmentation and nighttime wandering are common reasons for institutionalization of elderly adults. Improvement of nighttime sleep quality may delay institutionalization and enhance the quality of life for those living in nursing homes. Objectives: To determine whether fragmented sleep in nursing home patients would improve with increased exposure to bright light. Design: Randomized controlled trial. Setting: Two San Diego area nursing homes. Participants: 77 (58 women, 19 men) nursing home residents participated. Mean age was 85.7 years (SD=7.3, range=60-100 years) and mean MMSE was 12.8 (SD=8.8, range=0-30). Interventions: Participants were assigned to one of four treatments: evening bright light, morning bright light, daytime sleep restriction or evening dim red light. Measurements: Improvement in nighttime sleep quality, daytime alertness and circadian activity rhythm parameters. Results: There were no improvements in nighttime sleep or daytime alertness in any of the treatment groups. Morning bright light delayed the peak of the activity rhythm (i.e., acrophase) and increased the mean activity level (i.e., increased the mesor). In addition, subjects in the morning bright light group had improved activity rhythmicity during the 10 days of treatment. Conclusion: Increasing exposure to morning bright light delayed the acrophase of the activity rhythm and made the circadian rhythm more robust. These changes have the potential to be clinically beneficial as patients who have more socially acceptable circadian activity patterns may be easier to provide nursing care.
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