In a new study, researchers found that a tailored lighting intervention can lessen the impact of these symptoms in older adults living with Alzheimer’s disease and related dementias.
The research was conducted by a team at Rensselaer Polytechnic Institute.
Most people associate Alzheimer’s disease with profound memory loss.
But it is often the symptoms—sleep disturbances, depression, and agitation—that are a challenge to treat, and can strongly reduce the quality of life for both the affected individual and their family members and caregivers.
Using a variety of light sources, such as floor luminaires, lightboxes, and light tables, to deliver the tailored, individualized lighting intervention, the team examined 46 patients with moderate to late-stage Alzheimer’s disease in eight long-term care facilities.
The team found that compared to baseline, the active lighting intervention strongly improved sleep quality, and reduced depressive symptoms and agitation behavior.
The 24-hour light and dark pattern strongly determines a person’s sleep-wake cycle, telling the body when to go to sleep and when to wake up.
Studies have shown that daytime light exposure of 350–500 lux at the eyes can improve nighttime sleep efficiency and increase daytime wakefulness by promoting circadian entrainment.
Lighting in long-term care facilities is usually not bright enough during the day and perhaps too bright during the evening.
Typical indoor lighting provides less than 100 lux at the eye, whereas being outside on a sunny day will provide anywhere from 1,000 to more than 10,000 lux at the eye.
Older adults in long-term care facilities often spend their days and nights in dimly-lit rooms with minimal time spent outdoors, and thus, are not experiencing the robust daily patterns of light and dark that synchronize the body’s circadian clock to local sunrise and sunset.
Therefore, it is understandable that many older adults in long-term care facilities are plagued by insomnia and other sleep disorders—yet, sleep could not be more important to their overall health and wellbeing.
Recent research has shown that poor sleep may directly impact the onset and progression of Alzheimer’s disease, and conversely, healthy, regular sleep patterns may prevent or slow the progression of the disease.
This research suggests a strong link between sleep disruption and the deposit of amyloid-beta, the main component of the amyloid plaques found in the brains of individuals diagnosed with Alzheimer’s disease.
The lead author of the study is Mariana Figueiro, a professor and the director of the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute.
The study is published in the Journal of Clinical Sleep Medicine.
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