The effects of REM sleep deprivation on the level of sleepiness/alertness.

STUDY OBJECTIVES The purpose of this study was to evaluate the effects of acute REM deprivation on daytime sleepiness/alertness, as measured by the MSLT. PARTICIPANTS Twenty-six healthy, normal volunteers (14 males and 12 females) participated in this study. Participating subjects were in good physical and psychological health and were asymptomatic as to sleep/wake complaints. INTERVENTIONS Subjects spent 5 nights and 5 days in the laboratory. The first night and day were utilized for screening purposes. The remaining stay in the laboratory consisted of a baseline night and day, 2 deprivation nights and days, and a recovery night and day. Each night, a nocturnal polysomnogram was employed to monitor subjects' sleep. Each day, subjects underwent an MSLT to evaluate their sleepiness/alertness. Subjects were randomized into REM-deprivation (RD) and yoked-control (YC) groups. On deprivation nights, RD subjects were awakened each time they entered stage REM sleep, and the YC subjects were awakened concomitantly with the RD subjects, assuming they were not in stage REM sleep. RESULTS The REM-deprived subjects did not demonstrate any changes in MSLT scores across experimental days. In contrast, the YC subjects documented significantly lower MSLT scores on deprivation days due to decreased total sleep time. CONCLUSION The REM-deprivation procedure antagonized the effects of sleep loss on daytime sleepiness, resulting in increased alertness for RD subjects compared to YC subjects. The mechanism by which REM deprivation exerts its alerting effects is unknown and will require future research.