While light therapy has been used to treat depression (often in those with seasonal affective disorder), researchers are finding that it may also be a powerful approach to relieve symptoms related to Alzheimer’s disease.
A new scientific review of 15 randomized controlled trials involving nearly 600 patients with Alzheimer’s revealed that light therapy not only alleviated depression, it also reduced sleep troubles and agitated behavior (such as abnormal vocalization, restlessness, and repetitive movement).
“These findings combined with its low side effects suggest the role of light therapy as a promising treatment for Alzheimer’s disease,” concluded Qinghui Meng, PhD, a professor in the school of nursing at Weifang Medical University in China, and her coauthors.
The study, published this week in the journal PLoS One, drew on trials conducted in seven different countries between 2005 and 2022, all related to light therapy intervention for Alzheimer’s disease. Most of the 598 participants had mild to moderate dementia, and they ranged in age from 60 to 85 years old.
Issues With Sleep and Behavior Are Prevalent With Alzheimer’s
In patients with Alzheimer’s, sleep disorders are common, with about 70 percent experiencing sleep disruption in the early stages, according to Dr. Meng and her colleagues.
Light therapy led to overall improvements in sleep quality, reduced daytime sleep, and increased nighttime rest, the researchers noted. Results also indicated a benefit related to circadian rhythm (the 24-hour internal clock in our brain that regulates sleep-wake cycles).
Light therapy also had a positive impact on psycho-behavioral problems, which affect an estimated 90 percent of people with Alzheimer’s, the researchers say. The new study found light therapy appeared to decrease agitated behavior and depressive symptoms, which in turn reduced caregiver burden and distress.
The researchers also found some evidence that light therapy was associated with lower measures of cognitive impairment and higher measures of cognitive function. Confused thinking and memory issues are signature symptoms of Alzheimer’s.
