Lighting and Alzheimer’s disease and related dementias: Spotlight on sleep and depression

Abstract

Alzheimer’s disease and related dementias is the collective term for a progressive neurodegenerative disease for which there is presently no cure. This paper focuses on two symptoms of the disease, sleep disturbances and depression, and discusses how light can be used as a non-pharmacological intervention to mitigate their negative effects. Bright days and dark nights are needed for health and well-being, but the present components of the built environment, especially those places where older adults spend most of their days, are too dimly illuminated during the day and too bright at night. To be effective light needs to be correctly specified, implemented and measured. Yet, without the appropriate specification and measurement of the stimulus, researchers will not be able to successfully demonstrate positive results in the field, nor will lighting designers and specifiers have the confidence to implement lighting solutions for promoting better sleep and mood in this population.

Perceived visual comfort and usefulness of a circadian lighting system implemented at a nursing home

“…nocturnal wandering and sundown syndrome, where previous studies have reported a positive effect on sleep when employing dynamic lighting (e.g. lighting that imitates the natural daylight) as a nonpharmacological treatment [12,13,27,28,35]. Similar to the experiences of the staff that was reported in this study, previous studies have addressed how reduction in nocturnal activity can decrease the caregivers' burden and workload, which in turn can increase job satisfaction [16,18,28].…”

High circadian stimulus lighting therapy for depression: Meta-analysis of clinical trials

“…Hence, elderly patients receive markedly weaker circadian stimulation than non-elderly patients, prompting caution in the evaluation and quantification of CS in elderly patients. Another study also observed the positive effects of lighting with CS = 0.3 on depression therapy in older persons at risk for Alzheimer's disease (Figueiro and Kales, 2021). Therefore, more clinical research focusing on elderly patients is required due to the limited number of studies.…”

Effects of light on sleep in older adults: a scoping review

“…Xiang et al 11 recommended that during daytime the living space of elderly buildings should provide a high amount of sun light and artificial lighting, while at night the light level should be reduced, preferably to a warm illumination. Figueiro and Kales 21 suggested that designers should consider using 24-hour lighting solutions in common areas where residents were more likely to spend their waking hours. The light recommended by the circadian system should also be sufficient for older adults to perform visual tasks on a daily basis and more localized lights need to be set up to perform tasks that require discerning details, for example, reading bottle labels.…”

“…However, older adults usually receive insufficient sun light 36,48 . Given the benefits of outdoor The interior lighting design of the elderly building should follow the human-centered design concept, providing different ways of lighting for the elderly to meet their individual needs in different spaces Shan 41 China Qualitative research By simulating the standard units of senior apartments, it was concluded that the physiological rhythm of the elderly is best maintained when the building faces south, followed by east and west, and north is the lowest Yuan 42 China Qualitative research For the lighting design of the living space of the elderly building, choose indirect lighting for the route to the toilet and choose low color temperature warm light source for facilitate older adults to fall asleep again Fang et al 43 China Qualitative research Residential spaces in institutional senior living facilities can mitigate the impact on cohabiting seniors by adding supplemental lighting, while providing individualized lighting needs Figueiro and Kales 21 USA Qualitative research For older adults in long-term care facilities, designers should consider using a 24-h lighting scheme in common areas where residents are more likely to spend their waking hours Tholking et al 44 The Netherlands Quasi-experimental study Gight shows promising results in terms of sleep quality of community-dwelling older people Le et al 45 China, Canada, USA Qualitative research Dynamic white lighting system aids sleep by causing strong suppression of melatonin in the morning/early afternoon, moderate suppression in the evening, and no suppression at night daytime light on sleep quality, appropriate outdoor activities should be organized for older adults to create sun light exposure opportunities 34,40,49 . Currently, most findings are from qualitative studies, making it challenging to determine the optimal duration and frequency of exposure for older adults.…”

“…Several systematic reviews have examined the effects of light on sleep among older adults 12,13,[17][18][19][20][21] . However, these systematic reviews focus on the effects of light interventions on sleep in older adults in relation to specific diseases such as Alzheimer disease (AD) 12,17,[19][20][21] , Parkinson disease 13 , and insomnia 18 . No reviews have synthesized the comprehensive evidence of effects of light on sleep in general older adults.…”