Researchers Say Sundowning, a Difficult Alzheimer’s Symptom, May Be Related to Light Sensitivity

Sundowning is a term describing difficulties people with Alzheimer’s have during dusk and overnight. This may include trouble sleeping, anxiety, agitation, and disorientation. A new study may have uncovered one of the mechanisms behind these issues.

Senior couple walking on beach at sunset

Researchers from UVA Health recently used mouse models to study the Circadian rhythms that go along with Alzheimer’s disease. In the study, the findings of which are published in Frontiers in Aging Neuroscience, the team gave something resembling jet lag to mice with and without Alzheimer’s. This involved observing the animals on a running wheel after they’d advanced the light dark cycle by six hours.

In so doing, the team found that the mice with Alzheimer’s adapted more quickly to the change than did the control mice. They thought this might have to do with inflammation in the brain, so they tested that by examining microglia – immune cells activated in Alzheimer’s. However, when they depleted the microglia, it didn’t change things.

Ultimately, the team believes their findings suggest enhanced sensitivity to light may be behind sundowning. If this proves to be true, the findings could help minimize nighttime disruptions in Alzheimer’s patients and may even lead to possible treatments.

Senior man having trouble sleeping

Dr. Heather Ferris, study co-author from the University of Virginia School of Medicine’s Division of Endocrinology and Metabolism, says, “These data suggest that controlling the kind of light and the timing of the light could be key to reducing circadian disruptions in Alzheimer’s disease. We hope that this research will help us to develop light therapies that people can use to reduce the progression of Alzheimer’s disease.”

If your loved one is dealing with sundowning, the Alzheimer’s Association offers some tips. Encourage them to get plenty of rest, schedule important activities or appointments for the morning or early afternoon, reduce stimulation in the evening, have a larger lunch and a smaller dinner, and limit daytime naps if your loved one has trouble sleeping at night.

Senior man frustrated that he can't sleep
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