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CHICAGO -- Special lighting can help improve sleep and mood in people with Alzheimer's disease, researchers reported here.

In the crossover study, tailored lighting intervention was associated with a decrease in sleep disturbances measured by the , according to lead author Mariana Figueiro, PhD, of the Rensselaer Polytechnic Institute in Troy, New York, and colleagues:

• Active lighting arm: 10.4 ± 0.4 baseline versus 6.4 ± 0.5 after 4 weeks
• Inactive lighting arm: 9.7 ± 0.5 baseline versus 8.0 ± 0.4 after 4 weeks

Presented at the , the researchers also saw similar short-term improvements in the patients' levels of agitation (measured by the Cohen-Mansfield Agitation Index) and mood (measured by the ):

• Active lighting arm (agitation): 43.6 ± 2.5 baseline versus 37.5 ± 1.9 after 4 weeks
• Inactive lighting arm (agitation): 41.5 ± 1.8 baseline versus 40.4 ± 1.9 after 4 weeks
• Active lighting arm (mood): 10.9 ± 1.1 baseline versus 7.3 ± 0.7 after 4 weeks
• Inactive lighting arm (mood): 10.6 ± 0.9 baseline versus 9.1 ± 0.9 after 4 weeks

"This is sort of a low-tech way that really could address some of these symptoms that are so troubling and difficult for people to sometimes manage," commented Heather Snyder, PhD, senior director of medical and scientific operations for the Alzheimer's Association, who wasn't involved with the study. "It's not just turning the lights on longer. It's actually changing the type of light as well as the duration -- during wake-hours, you have more exposure to this type of light," she told MedPage Today.

"We know from the lab studies we and others have performed that light is the major synchronizer of circadian rhythms to the local time," Figueiro explained. "Misalignment of circadian rhythms, or circadian disruption resulting from constant dim light -- typically found in nursing homes -- can lead to poor sleep."

She also noted how prior research has suggested very bright light in the daytime consolidated rest-activity rhythms and was beneficial for improving sleep in these patients.

"Our work helped us understand the type of light that could more effectively accomplish this," she said and explained how tailored light that's brighter and emits more blue light can help deliver more circadian stimulation. "Given that Alzheimer's disease patients are in constant dim light, we thought it would be a nice, simple way to help them with improving their sleep and mood."

The analysis included 60 individuals with Alzheimer's disease and related dementia residing in a nursing home, who were an average of nearly 86 years old. Novel lighting mechanisms were developed and implemented according to where the patients spent most of their time. These included lighting tables placed in common areas of the nursing home and smaller lamps placed in patient's rooms.

"With the new light emitting diode (LED) technology, it is a lot easier now because the amount and color can be easily controlled. It is important to deliver high circadian stimulus during the day and low in the evening to provide patients with a robust light-dark patterns," explained Figueiro, also highlighting her Lighting Research Center's .

The first phase of the study assessed the short-term effects of the tailored lighting intervention over the course of 4 weeks. After that, a long-term assessment phase began, which included only active lighting intervention for 6 months.

During this 6-month exposure, all measures assessed -- sleep disturbances, agitation, and mood -- continued to improve even more. Specifically, depression scores improved to the extent where those with dropped below the threshold of having depression. Similarly, levels of sleep disturbances dropped to the point where the patient was not considered to have disturbed sleep any longer.

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