PHOTOTHERAPY FOR PATIENTS WITH ALZHEIMER-DISEASE WITH DISTURBED SLEEPPATTERNS - RESULTS OF A COMMUNITY-BASED PILOT-STUDY

We examined the entraining effects of phototherapy delivered by light visors on disturbed sleep patterns of community-dwelling research subj ects with Alzheimer disease (AD). The pilot project used a single subj ect design and activity monitoring as the primary outcome measures. Th e protocol consisted of a 5-day baseline monitoring period followed by 10 consecutive days of phototherapy (2,000:lux of full spectrum brigh t light) delivered by light visors for:! hours each morning; this was followed by an additional 14 days of activity monitoring. Cosinor anal yses found no consistent changes in acrophase, mesor, or amplitude. Ob served changes in acrophase were consistent with phase advancement of the rest-activity cycle and consistent with the biological interventio n. Changes in the number of nighttime awakenings were not found. One s ubject had a significant increase in total sleep time, whereas another had a significant decrease in total sleep time. Failure to find a con sistent biological effect of light on AD subjects may be secondary to: (1) insufficient duration of light exposure; (2) timing of light admi nistration (given at a time when circadian rhythm is refractory to the effects of light); (3) advanced stages of AD making the Y circadian p acemaker in the suprachiasmatic nucleus of the hypothalamus insensitiv e to the biological effects of light; and (4) inadequacy of light viso rs as a means of providing light.