Bright Light Therapy and Its Use in Alzheimer's Disease

Bright light therapy consists of regular exposure to a light anywhere from five to 30 times brighter than typical office lights. The light is placed in a box with a screen that diffuses it. The person receiving bright light therapy is asked to sit in front of the light source for a set amount of time each day.

Originally intended for people struggling with seasonal affective disorder (SAD), bright light therapy has also been used to treat circadian problems, where people have trouble sleeping well at night.

More recently, bright light therapy has been researched and used as a complementary therapy for people with Alzheimer's disease and other related dementias since it may offer some similar benefits to medication, but not have the potential for negative side effects or medication interactions.

Woman using Bright Light Therapy
BSIP / UIG Universal Images Group / Getty Images

The Potential Benefits

There are several possible benefits of bright light therapy in dementia. These include the following.

Improved Sleep Cycles

Sleep disturbances are a common problem in Alzheimer's and other kinds of dementia, and medications to induce sleep tend to have significant risks and side effects.

One study tracked the sleep habits of 11 nursing home patients with dementia and found that their sleeping habits improved significantly following bright light therapy.

Multiple other studies have shown similar effectiveness of bright light therapy. One study measured the combination of bright light therapy with walking and found a notable improvement in sleeping habits when both walking and bright light therapy were practiced daily.

Still another study measured the combination of bright light therapy with the use of melatonin. The researchers found that the participants, all of whom had dementia, experienced an improvement in their sleep cycles when exposed to bright light therapy, but interestingly, not when the bright light therapy was combined with melatonin.

One other small study found that morning administration of bright light therapy in persons with mild to moderate Alzheimer's disease found decreased sleep disturbances in some of the participants.

Decreased Wandering

Some research has shown that in addition to improving the sleep-wake cycle, bright light therapy also decreased wandering for people with dementia throughout the night. Wandering can be a serious behavioral concern since it can impact the safety of the person with dementia, as well as the sleep patterns of both the person and the caregiver.

Improved Cognition

Bright light therapy has been associated with improved scores on the Mini Mental State Exam, a test that measures cognitive ability. Persons living with Alzheimer's disease or vascular dementia who were exposed to bright light therapy demonstrated significantly improved scores on the MMSE, compared to no change on the scores when they were exposed to dim light therapy.

Another study demonstrated improved cognitive functioning after bright light therapy, but only for those who were in the early stages of Alzheimer's, as opposed to the middle or later stages.

Improved Behavioral Functioning

One study found that participants, all of whom had a diagnosis of dementia, showed an improvement in the challenging behaviors that often accompany Alzheimer's. However, another study compared the levels of agitation when people with dementia were exposed to light therapy and found no difference in their agitation.

Decreased Depression and Agitation

A study of 60 older adults with dementia measured the effects of bright light therapy as compared to low-intensity light exposure. It found that bright light therapy was associated with significantly reduced levels of both depression and agitation.

A second study also found that depressive symptoms in people with all stages of dementia, including the late stages, improved with exposure to bright light therapy.

Talk to Your Physician

Please note that if bright light therapy sounds like something you or your loved one would benefit from, you should discuss it with your physician, as there are a few situations where it might not be medically appropriate or could even be harmful.

A Word From Verywell

While bright light therapy has been well-researched as a treatment for SAD, it still requires additional and more rigorous studies to prove its effectiveness in Alzheimer's disease and other types of dementia. However, given that we are still very limited in the availability of effective medical treatments for dementia, bright light therapy does show promise as a complementary approach to improving quality of life in those living with dementia.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Esther Heerema, MSW
Esther Heerema, MSW, shares practical tips gained from working with hundreds of people whose lives are touched by Alzheimer's disease and other kinds of dementia.