Bright Light Therapy and Its Use in Alzheimer's Disease

Benefits of Bright Light Therapy
BSIP/UIG Universal Images Group/ Getty Images

What Is Bright Light Therapy?

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 complimentary therapy for people with Alzheimer's disease and other related dementias since it may offer some similar benefits to medication, but it not have the potential for negative side effects or medication interactions.

What Are the Benefits of Bright Light Therapy for People with Dementia?

  • Improved Sleep Cycles

    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 not when the bright light therapy was combined with melatonin.

  • 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 patient 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. Patients with Alzheimer's disease or vascular dementia who were exposed to bright light therapy had 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.

While the jury is still out on the effect of bright light therapy on behaviors, numerous studies have demonstrated the benefits to the circadian rhythm for those with dementia.

Don't Attempt Bright Light Therapy Without the Direction of 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.


Alzheimer's Society. Complementary and alternative therapies and dementia. Accessed October 28, 2012.

Biological Psychiatry. 2001 Nov 1;50(9):725-7. The effects of light therapy on mini-mental state examination scores in demented patients. Accessed October 28, 2012.

Biological Psychiatry 1997 May 1 41 955-963. Indirect bright light improves circadian rest-activity rhythm disturbances in demented patients. Accessed October 28, 2012

Columbia University. Q&A on Bright Light Therapy. Accessed October 30, 2012.

International Journal of Geriatric Psychiatry. 2003 Jun;18(6):520-6. Bright light treatment improves sleep in institutionalised elderly--an open trial.

International Journal of Geriatric Psychiatry. Volume 25, Issue 10, pages 1013–1021, October 2010. Impact of ambient bright light on agitation in dementia. Accessed October 28, 2012.

International Journal of Geriatric Psychiatry. Volume 16, 106-110 (2001). Bright Light Therapy and Melatonin in Motor Restless Behaviour in Dementia: A Placebo-Controlled Study. Accessed October 28, 2012.;2-9/abstract

Journal of the American Geriatrics Society. 2011 Aug;59(8):1393-402. Increasing walking and bright light exposure to improve sleep in community-dwelling persons with Alzheimer's disease: results of a randomized, controlled trial. Accessed October 28, 2012.

Psychiatry and Clinical Neurosciences. 2004 Aug;58(4):343-7. Improvement in behavioral symptoms and advance of activity acrophase after short-term bright light treatment in severe dementia. Accessed October 28, 2012.

Psychiatry and Clinical Neurosciences. 2000 Jun;54(3):352-3. Effects of bright light on cognitive and sleep-wake (circadian) rhythm disturbances in Alzheimer-type dementia. Accessed October 28, 2012.

Continue Reading