title: Cognitive processes in disorders of consciousness as revealed by EEG time-frequency analyses.
abstract: OBJECTIVE
  Although behavioral evaluation of awareness in disorders of consciousness is difficult it remains the clinical standard. We believe that the refinement of EEG and analyses techniques would improve our characterization of those patients.
  
  
  METHODS
  We focused on cognitive processing in a sample of 12 control subjects, eight vegetative-state patients, and 13 patients in the minimally consciousness state using EEG. We used an 'active paradigm' which asks subjects to follow instructions, specifically to actively count own or other names as compared to passively listening to them. EEG data was then analyzed using an advanced EEG analysis technique.
  
  
  RESULTS
  Results revealed that all groups exhibit a stronger theta-synchronization to their own names when forced to count them. We also observed a delay in theta power in response to targets relative to non-targets when participants were instructed to count their own name.
  
  
  CONCLUSIONS
  Active paradigms are able to induce a different oscillatory activity compared to passive paradigms. Differences between controls and the pathologic groups are prominent in the theta- and alpha-band.
  
  
  CONCLUSIONS
  Time-frequency analyses allow to focus on distinct cognitive processes in patients with disorders of consciousness and thereby contribute to a refined understanding of severely brain-injured patients.
authors.affiliation: Department of Psychology, Laboratory for Sleep and Consciousness Research and Division of Physiological Psychology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Fellinger
authors.forename: W
authors.initials: W
authors.lastname: Klimesch
authors.forename: C
authors.initials: C
authors.lastname: Schnakers
authors.forename: F
authors.initials: F
authors.lastname: Perrin
authors.forename: R
authors.initials: R
authors.lastname: Freunberger
authors.forename: W
authors.initials: W
authors.lastname: Gruber
authors.forename: S
authors.initials: S
authors.lastname: Laureys
authors.forename: M
authors.initials: M
authors.lastname: Schabus
mesh_terms: D000328:Adult; D000368:Aged; D001364:Awareness / Q000502:physiology; D058256:Brain Waves / Q000502:physiology; D003071:Cognition / Q000502:physiology*; D003243:Consciousness / Q000502:physiology; D004569:Electroencephalography / Q000379:methods*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018458:Persistent Vegetative State / Q000175:diagnosis* / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted