Research in sleep deprivation has in general concentrated on behavioral, psychological, and electroencephalographic measures of functioning. Deficits in psychological test performance, psychotic behavior, and decrease in EEG α-activity have all been described but not fully explained.
Williams, Lubin, and Goodnow7 have attributed both the deterioration in psychological test performance and the perceptual disturbances of sleep deprivation to periodic lapses or brief periods of somnolence in which sensory input is partially or totally blocked. This would imply a gradually decreasing level of activation and this is supported by disappearance of EEG α-activity during periods of unresponsiveness. Malmo,5 on the other hand, interpreting sleep deprivation within the framework of Hullian theory, has suggested that it produces a state of high arousal or activation and offered autonomic evidence in support. Using continuous polygraph recording he observed an upward shift in the physiology