Last Updated: 2008-06-10 16:00:08 -0400 (Reuters Health)

Daily exposure to bright light may slightly improve cognitive and noncognitive symptoms of dementia in elderly residents of group care facilities, according to a report in the Journal of the American Medical Association for June 11.

In addition, treatment with melatonin may improve sleep, although the authors caution that it should not be given in the absence of bright light as it may adversely affect mood.

"The simple measure of increasing the illumination level in group care facilities ameliorated symptoms of disturbed cognition, mood, behavior, functional abilities, and sleep," conclude Dr. Eus J. W. Van Someren, from the Netherlands Institute for Neuroscience in Amsterdam, and colleagues. Because no adverse effects were noted, bright light therapy "could be considered for use in care facilities for elderly individuals with dementia."

The study involved 189 residents of 12 group care facilities in the Netherlands. The subjects were almost 86 years old on average, and 164 of them met criteria for dementia of various types. The other 25 participants stayed in the facilities for other medical or psychosocial reasons.

The facilities were randomized to provide either whole-day bright light (approximately 1000 lux) or dim light (approximately 300 lux), and the subjects were randomized to receive evening melatonin or placebo for an average of 15 months.

Exposure to bright light was associated with modest improvements in cognitive function, depressive symptoms, and functional limitations.

Melatonin therapy reduced sleep onset latency and increased sleep duration. However, as noted, without exposure to bright light, this treatment adversely affected mood.

Combined treatment with bright light and melatonin reduced aggressive behavior and agitation, increased sleep efficiency, and improved nocturnal restlessness.

While the findings were statistically significant, yet relatively modest, the authors believe that they are clinically relevant on the whole.

JAMA 2008;299:2642-2655.

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