Adding Light Eases Behavioral Problems of Dementia

TUESDAY June 10, 2008 -- Relatively simple adjustments in lighting may ease some of the behavioral problems associated with dementia, new research suggests.

Use of melatonin, a hormone which seems to play a role in the sleep-wake cycle, also helped patients sleep better at night.

Both strategies could greatly improve quality of life for both patients and caregivers, said the authors of a study in the June 11 issue of the Journal of the American Medical Association.

"Elderly residents of group-care facilities should preferably be housed in a brighter environment," said study senior author Eus J. W. Van Someren, of the Netherlands Institute for Neuroscience in Amsterdam. "This has a strong impact on their quality of life. The favorable effects are not limited to cognition, but also include strong effects on mood and functional limitations in activities of daily living."

The benefits may even surpass those of cholinesterase inhibitors such as Aricept, which are commonly prescribed to limit cognitive decline in Alzheimer's patients, the authors stated.

Not only do individuals with dementia experience memory and other problems with cognition, they often end up with mood, behavior, sleep and functional disturbances.

A recent study found that anti-psychotic medications often prescribed for behavioral problems such as aggression and agitation can increase the risk of hospitalization and even death. Unfortunately, alternatives to these drugs are limited.

But there has been some evidence that disturbances in circadian rhythms and sleep-wake cycles might be at play in patients with dementia, and that interventions aimed at these processes might provide relief.

"In advanced Alzheimer's, the circadian rhythm becomes asynchronous," explained Dr. Christopher C. Colenda, the Jean and Thomas McMullin Dean of Medicine at Texas A&M Health Science Center College of Medicine. "The pathology of Alzheimer's begins to affect areas of the brain that are associated with the normal sleep-wake cycle. One of the most powerful entrainers [modifiers] of the sleep-wake cycle is bright light."

Colenda has published shorter-term studies that found that giving full-spectrum bright light to Alzheimer's patients showed some evidence of normalizing the day-night cycle.

The study involved 189 residents of 12 group-care facilities in the Netherlands, 87 percent of whom suffered from dementia. The mean age was 86.

Participants were randomly assigned (by facility) to receive either long-term daily treatment with bright or dim light and (by participants) to receive 2.5 milligrams of melatonin in the evening or a placebo for up to 3.5 years.

Half of the facilities involved had bright lighting mounted in the ceiling which were on from about 9 a.m. to 6 p.m. every day.

Bright light reduced cognitive deficits by 5 percent, cut symptoms of depression by 19 percent and decreased the gradual increase in functional limitations by 53 percent, relative to the dim-light group.

The results on melatonin were mixed: While (in combination with bright light) it reduced the time it took to fall asleep by 19 percent, increased mean duration of uninterrupted sleep by 25 percent, and decreased agitated behavior by 9 percent, melatonin had no effect on depressive symptoms and, in fact, increased withdrawn behavior, according to caretakers.

The authors speculated that the dose of melatonin was too high and that a lower dose should be considered.

"The sleep-cycle and dysregulation of the sleep cycles are important contributors to behavioral problems in Alzheimer's patients, especially in later stages of the disease, so if there is an environmental intervention like light that can help, that's a good deal," Colenda said.

"The interesting thing is that even though the brain is diseased in Alzheimer's, it still has some malleability for intervention that may help promote better quality of life for patients and their families," he added.

More information

The U.S. National Library of Medicine has more on different types of dementia.

Posted: June 2008


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