ARTICLE
Figueiro et al. (2014). Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities. Dovepress, volume 2014:9, pages 1527-1537.
Abstract
Background: Light therapy has shown great promise as a nonpharmacological method to improve symptoms associated with Alzheimer’s disease and related dementias (ADRD), with preliminary studies demonstrating that appropriately timed light exposure can improve nighttime sleep efficiency, reduce nocturnal wandering, and alleviate evening agitation. Since the human circadian system is maximally sensitive to short-wavelength (blue) light, lower, more targeted lighting interventions for therapeutic purposes, can be used.
Methods: The present study investigated the effectiveness of a tailored lighting intervention for individuals with ADRD living in nursing homes. Low-level “bluish-white” lighting designed to deliver high circadian stimulation during the daytime was installed in 14 nursing home resident rooms for a period of 4 weeks. Light–dark and rest–activity patterns were collected using a Daysimeter. Sleep time and sleep efficiency measures were obtained using the rest–activity data. Measures of sleep quality, depression, and agitation were collected using standardized questionnaires, at baseline, at the end of the 4-week lighting intervention, and 4 weeks after the lighting intervention was removed.
Results: The lighting intervention significantly (P<0.05) decreased global sleep scores from the Pittsburgh Sleep Quality Index, and increased total sleep time and sleep efficiency. The lighting intervention also increased phasor magnitude, a measure of the 24-hour resonance between light–dark and rest–activity patterns, suggesting an increase in circadian entrainment. The lighting intervention significantly (P<0.05) reduced depression scores from the Cornell Scale for Depression in Dementia and agitation scores from the Cohen–Mansfield Agitation Inventory.
Conclusion: A lighting intervention, tailored to increase daytime circadian stimulation, can be used to increase sleep quality and improve behavior in patients with ADRD. The present field study, while promising for application, should be replicated using a larger sample size and perhaps using longer treatment duration.
Keywords: sleep disorders, light therapy, circadian rhythms, ADRD
Experts
Mariana G. Figueiro, Ph.D., is Director of the Light and Health Research Center (LHRC) at Mount Sinai and Professor of Population Health Science and Policy at the Icahn School of Medicine at Mount Sinai. Dr. Figueiro is well known for her research on the effects of light on human health, circadian photobiology, and lighting for older adults. In 2013, she was elected Fellow of the Illuminating Engineering Society. She is the author of more than 150 scientific articles in her field of research, and her research is regularly featured in national media, including a TEDMED talk.
Mark S. Rea is Director of the Lighting Research Center (LRC) and Professor of Architecture and Cognitive Sciences at Rensselaer Polytechnic Institute. Rea is well known for his research in circadian photobiology, mesopic vision, psychological responses to light, lighting engineering, and visual performance. He is the author of more than 250 scientific and technical articles and was the editor-in-chief of the 8th and 9th editions of the Illuminating Engineering Society of North America (IESNA) Lighting Handbook. His recent book Value Metrics for Better Lighting brings together a wide range of research to illustrate how the effective use of light can benefit society and the environment.