INDIRECT BRIGHT LIGHT IMPROVES CIRCADIAN REST-ACTIVITY RHYTHM DISTURBANCES IN DEMENTED PATIENTS

Light is known to be an important modulator of circadian rhythms, We t ested the hypothesis that an enduring increase in the daytime environm ental illumination level improves rest-activity rhythm disturbances in demented patients. Actigraphy was performed before, during, and after 4 weeks of increased illumination in the living rooms of 22 patients with dementia clinically diagnosed as probable Alzheimer's disease, mu lti-infarct dementia, dementia associated with alcoholism, or normal p ressure hydrocephalus. The results indicated that during increased ill umination, the stability of the rest-activity rhythm increased in pati ents with intact vision, but not in visually impaired patients. (C) 19 97 Society of Biological Psychiatry.