CAN NORMAL SUBJECTS BE MOTIVATED TO FALL ASLEEP FASTER

The Multiple Sleep Latency Test (MSLT) is widely believed to offer an objective, physiological measure of sleepiness. The speed with which a person falls asleep throughout the day is understood to be related sy stematically to sleep need and circadian phase. This study examined wh ether normal subjects (n = 14 young female adults) could achieve faste r MSLT sleep onsets if they were given the incentive to do so. During week 1 baseline MSLTs were determined over 1 day for all subjects. In week 2 they were randomly assigned to two groups. Control subjects und erwent a second MSLT testing day identical to that of week 1, whereas Incentive subjects had an additional financial incentive to sleep. The re was a significant reduction in sleep onset latency (indicating incr eased sleepiness) during the 1500 h trial following the incentive, whe n subjects also reported a significantly greater increase in sleepines s over the trial. These findings suggest that when coupled with a mid- afternoon increase in sleepiness, increased motivation to sleep can re duce sleep onset latency.