SLEEP LATENCY MEASURES OF CAFFEINE EFFECTS DURING SLEEP-DEPRIVATION

Studies of stimulants during sleep deprivation have used performance a ssessment batteries (PABs) and occasionally the multiple sleep latency test (MSLT) as measures. Another type of sleep latency test, the main tenance of wakefulness test (MWT), assesses ability to remain awake wi thout assistance, rather than ability to go to sleep. The MWT previous ly has not been used in studies of stimulants during sleep deprivation . This study of caffeine during 64 h without sleep included a PAB, the MSLT, and a single MWT trial per day. The PAB and the MSLT were sensi tive to caffeine effects during the first 24 h without sleep. The MWT demonstrated that caffeine improved ability to remain awake even after 2 nights of sleep deprivation. Ability to go to sleep and ability to stay awake during sleep deprivation appear to be affected differently by caffeine. PAB testing may fail to detect this stimulant effect beca use technicians prevent subjects from nodding off during PAB testing, an external support not available to subjects during the MWT and also not available in many real-world work environments. The MWT was more S ensitive to stimulant amelioration of sleep-deprivation effects. The f indings need to be validated with MWTs at other times of day and with other stimulants. (C) 1997 Elsevier Science Ireland Ltd.