SLOW-WAVE SLEEP-DEPRIVATION AND WAKING FUNCTION

Slow-wave sleep (SWS) has been theorized to be an intense form of nonR EM sleep, but selective deprivation of SWS or Stage 4 sleep has not be en shown to cause greater decrements in alertness or performance, comp ared to deprivation or disruption of the other stages of sleep. The pr esent experiment examined the effects of marked SWS deprivation (SD) f or two nights, a control sleep disruption (CD) condition in which minu tes of SWS were preserved, and a no sleep disruption (ND) condition. D aytime sleepiness was assessed with the multiple sleep latency test (M SLT) and performance was evaluated with the simulated assembly line ta sk (SALT), neither of which was used in previous studies of SWS or Sta ge 4 sleep deprivation. In agreement with prior studies, two nights of SD did not cause greater daytime sleepiness than did CD, although sle epiness in both conditions was increased compared to the ND condition. In addition, neither SD nor CD caused declines in performance or mood . However, post hoc analysis suggests an interaction between SWS and s leep duration, such that sufficient SWS may tend to prevent adverse ef fects of mild sleep loss on waking function.