Improvement in behavioral symptoms and advance of activity acrophase after short-term bright light treatment in severe dementia.

Ten elderly subjects with severe dementia were given bright light (5000-8000 lux) for 45 min each morning for 4 weeks. Two rating scales of behavioral symptoms in dementia were used as outcome measures: Cohen-Mansfield Agitation Inventory (CMAI) and Behavior Pathology In Alzheimer's Disease Rating Scale (BEHAVE-AD), a scale for sleep-wake disturbances, and actigraphy to monitor activity rhythm. Behavioral symptoms improved with treatment. No changes in sleep-wake measures were found. There was an advance of the activity rhythm acrophase during treatment. These results suggest that short-time bright light improves behavioral symptoms and aspects of activity rhythm disturbances even in severely demented subjects.