title: Time perception at different EEG-vigilance levels.
abstract: BACKGROUND
  Human time perception is influenced by various factors such as attention and drowsiness. Nevertheless, the impact of cerebral vigilance fluctuations on temporal perception has not been sufficiently explored. We assumed that the state of vigilance ascertained by electroencephalography (EEG) during the perception of a given auditory rhythm would influence its reproduction. Thus, we hypothesised that the re-tapping interval length and the accuracy of reproduction performance would vary depending on the state of vigilance determined by EEG.
  
  
  METHODS
  12 female and 9 male subjects ranging from 21 to 38 years (M = 25.52, SD = 3.75) participated in a test paradigm comprising a) a resting EEG for the determination of vigilance while an auditory rhythm was presented, b) a short activity of the proband to be sure of sufficient alertness, and c) a tapping task to reproduce the presented rhythm. Vigilance states of three consecutive 1-sec-EEG-segments of the resting EEG before the reproduction phase were classified using the Vigilance Algorithm Leipzig (VIGALL).
  
  
  CONCLUSIONS
  Reproduction accuracy was more precise after high EEG-vigilance stages. Thus, the subjects' mean deviation from the given rhythm was lower (t(17) = -2.733, p < 0.05) after high vigilance stage A (MW = 0.046, SD = 0.049) than after low vigilance stage B (MW = 0.065, SD = 0.067). The re-tapping-length was significantly shorter (t(17) = -2.190, p < 0.05) for reproduction phases following high EEG-vigilance stage A compared to the lower EEG-vigilance stage B.
  
  
  CONCLUSIONS
  These findings support the hypothesis of a varying time perception and of speed alterations of the internal clock after different states of EEG-vigilance, which were automatically classified by VIGALL. Thus, alterations of cognitive processing may be assessable by specific EEG-patterns.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Leipzig, Semmelweisstr, 10, 04103 Leipzig, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Minkwitz
authors.forename: Maja U
authors.initials: MU
authors.lastname: Trenner
authors.forename: Christian
authors.initials: C
authors.lastname: Sander
authors.forename: Sebastian
authors.initials: S
authors.lastname: Olbrich
authors.forename: Abigail J
authors.initials: AJ
authors.lastname: Sheldrick
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hegerl
authors.forename: Hubertus
authors.initials: H
authors.lastname: Himmerich
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D013998:Time Perception / Q000502:physiology*