2023 Alzheimer's Association Research Grant (AARG)
Environmental Influences on Circadian Rhythms in Sundowning and Alzheimer's
How do environmental conditions affect sleep-wake cycles and behaviors sometimes experienced by individuals with Alzheimer’s in the hours before sleep?
James Walton, Ph.D.
West Virginia University Research Corporation
Morgantown, WV - United States
Background
Circadian rhythms are natural biological changes that occur over an approximately 24-hour cycle, often called the sleep-wake cycle. For individuals living with Alzheimer’s, circadian rhythms can become disrupted and may lead to “sundowning,” a syndrome that involves agitation and aggressiveness in an individual during the hours before sleep.
Currently, no effective treatment for sundowning exists, but previous research suggests a link to circadian dysfunction. The most promising treatment, light therapy, involves exposure to bright lights during the day and may help regulate dysfunctional circadian rhythms. Previous clinical trials show mixed results in the efficacy of light therapy at relieving sundowning symptoms, which Dr. James Walton proposes is due to a failure to rigorously maintain an environment of complete darkness at night.
Research Plan
Using genetically engineered Alzheimer’s-like mice Dr. Walton and team will test whether dim light conditions at night affect sundowning behaviors. The mice will experience typical indoor light levels during daytime hours and either complete darkness or dim lighting at night. Dr. Walton proposes that dim light will disrupt circadian rhythms and lead to an increase in sundowning symptoms. In mice, sundowning is observed as increased movement, aggression, and anxiety-like behaviors during the hours right before sleep. The team will determine how circadian dysfunction plays a role in sundowning by measuring levels of chemical molecules in the brain and observing which genes turn “on” or “off” at different time points. Next the team will determine how effective bright light therapy is at treating sundowning by exposing mice to bright lights during waking hours and either complete darkness or dim light during the sleep cycle.
Impact
This research may demonstrate an inexpensive and non-invasive treatment method for improving sundowning symptoms in individuals living with Alzheimer’s.