EEG correlation and power during maintenance of wakefulness test after sleep-deprivation.

ABSTRACT

OBJECTIVES: To investigate whether there are any objective EEG characteristics that change significantly between specific time periods during maintenance of wakefulness test (MWT) and whether such changes are associated with the ability to appropriately communicate sleepiness. METHODS: After a night of total sleep deprivation, 12 healthy young subjects underwent a MWT whilst being instructed to communicate the experience of subjective sleepiness by pressing a button. EEG analysis consisted of average relative power and correlation between EEG signals. RESULTS: A comparison of the 30 s before microsleep (MS) with 30 s before subjects communicated experience of sleepiness (PB) showed increased ß correlation as well as increased power in the ß band (13-20 Hz) whereas power in the θ (4.5-7.5 Hz) and α (8-12.5 Hz) band was significantly decreased. When subjects later failed to communicate the experience of subjective sleepiness before (micro-)sleep occurred, average relative power and EEG correlation were significantly higher during 30 s following lights off in the δ (1-4 Hz) band and power in the α and ß bands was decreased. CONCLUSIONS: EEG spectral power and correlation change significantly in specific frequency bands between different time periods of MWT. Failure to communicate sleepiness is associated with certain precursors of EEG power and correlation. SIGNIFICANCE: This study demonstrates that there are specific EEG characteristics associated with impending failure to communicate sleepiness.