Effect of total sleep deprivation on the dimensional complexity of the waking EEG

Study Objectives: Sleep deprivation can affect the waking EEG that may refl ect information processing of the brain. We examined the effect of total sl eep deprivation (TSD) on nonlinear dynamics of the waking EEG. Design: Paired-group design Setting: A sleep disorders laboratory in a hospital. Participants: Twenty healthy male volunteers Interventions: Waking EEG data were recorded from subjects with eyes dosed after (a) an 8-hour night's sleep and (b) TSD for 24 hours. The dimensional complexity (D2), as a nonlinear measure of complexity, of the EEG after a full night sleep were compared with those of the EEG after TSD. Measurements and Results: The sleep-deprived states had lower D2 values at three channels (P4, O2, and C3) than normal states. Conclusions: TSD results in the decrease of complexity in the brain, which may imply sub-optimal information processing of the cerebral cortex:We sugg est that the investigation of the relation between nonlinear dynamics of th e waking EEG induced by TSD and cognitive performance may offer fruitful cl ues for understanding the role of sleep and the effects of sleep deprivatio n on brain function.