ENHANCED PERFORMANCE IN ELDERLY SUBJECTS FOLLOWING BRIGHT LIGHT TREATMENT OF SLEEP MAINTENANCE INSOMNIA

Sixteen older individuals with sleep maintenance insomnia were treated with nighttime bright-light exposure (BL) while living at home. Twelv e consecutive days of acute light treatment were followed by a 3-mo ma intenance light-treatment period. Subjects completed laboratory evalua tion sessions on five separate occasions (prior to and following the a cute light-treatment period, and once per month during the maintenance period). During each laboratory session, performance levels, sleep, a nd core body temperature were measured. The performance battery consis ted of four computerized tasks (Logical Reasoning, Stroop Congruency, Two Letter Visual Search, and Wilkinson Four-Choice Reaction Time) and was administered every 2 h between 10.00 and 18.00 hours. Subjects im proved significantly on three of the four tasks from pre-BL to post-BL . During the maintenance period, subjects who received active BL treat ment maintained significantly higher performance levels than a control BL group. Light treatment improved sleep efficiency and delayed the p hase of the body temperature rhythm. Performance improvements were sig nificantly related only to sleep and not to circadian phase. The impli cations for non-circadian treatments of sleep maintenance insomnia and cognitive functioning in the elderly are discussed.