Effects of spaced and repeated total sleep deprivation

Six young adult males were sleep deprived for 2 nights on five successive occasions at 3 week intervals. During the deprivation period they completed subjective ratings and performed on an extensive battery of tasks. Subjective measures and vigilance tasks showed substantial deprivation effects; the cognitively-demanding tasks were less affected. Where repetition of sessions resulted in changes, relative to sleep deprivation the effects were those of ‘sensitization’ rather than ‘immunization’.