Misperception and Disorientation During Sleep Deprivation

Until recently the most striking changes observed during experimental studies of sleep deprivation have been subjective ones. Performance variables have not been consistently sensitive to sleep loss. More than 60 years after the first laboratory study, in 1896,10a recent review concluded that “subjective attitude (appearance, mood, and behavior) is the only factor severely affected by sleep reduction.”5 Studies by the Walter Reed group3,11,14and by Wilkinson13and others indicate, however, that certain aspects of performance can be identified which are sensitive to sleep loss. In particular, tasks which require sustained attention show marked decrement as sleep loss increases. The most frequent changes reported in earlier studies were increased restlessness, apathy, irritability, inability to concentrate, visual illusions, and hallucinations. At least two investigators6,12reported extreme confusion and delusions of persecution. Recently, Bliss and his colleagues1conducted