The use of daytime bright lighting to improve the circadian rhythm of elderly people has been associated with modest improvement in symptoms of dementia, and the addition of the use of melatonin resulted in improved sleep, according to an article in JAMA.
"In elderly patients with dementia, cognitive decline is frequently accompanied by disturbances of mood, behavior, sleep, and activities of daily living, which increase caregiver burden and the risk of institutionalisation," the author write.
These symptoms have been associated with disturbances of the circadian rhythm (the regular recurrence, in cycles of about 24 hours, of biological processes or activities).
The researchers found that bright light lessened cognitive deterioration by 5%, reduced depressive symptoms by 19% and diminished the gradual increase in functional limitations by 53%.
Melatonin reduced the time to fall asleep by 19% and increased total sleep duration by 6%, but adversely affected caregiver ratings of withdrawn behavior and mood expressions. The addition of bright light improved the adverse effect on mood. In combination with bright light, melatonin reduced aggressive behavior by 9%.
"In conclusion, the simple measure of increasing the illumination level in group care facilities [improved] symptoms of disturbed cognition, mood, behavior, functional abilities, and sleep. Melatonin improved sleep, but its long-term use by elderly individuals can only be recommended in combination with light to suppress adverse effects on mood. The long-term application of whole-day bright light did not have adverse effects, on the contrary, and could be considered for use in care facilities for elderly individuals with dementia," the authors write.