title: Connectivity biomarkers can differentiate patients with different levels of consciousness.
abstract: OBJECTIVE
  In the present study, we searched for resting-EEG biomarkers that distinguish different levels of consciousness on a single subject level with an accuracy that is significantly above chance.
  
  
  METHODS
  We assessed 44 biomarkers extracted from the resting EEG with respect to their discriminative value between groups of minimally conscious (MCS, N=22) patients, vegetative state patients (VS, N=27), and - for a proof of concept - healthy participants (N=23). We applied classification with support vector machines.
  
  
  RESULTS
  Partial coherence, directed transfer function, and generalized partial directed coherence yielded accuracies that were significantly above chance for the group distinction of MCS vs. VS (.88, .80, and .78, respectively), as well as healthy participants vs. MCS (.96, .87, and .93, respectively) and VS (.98, .84, and .96, respectively) patients.
  
  
  CONCLUSIONS
  The concept of connectivity is crucial for determining the level of consciousness, supporting the view that assessing brain networks in the resting state is the golden way to examine brain functions such as consciousness.
  
  
  CONCLUSIONS
  The present results directly show that it is possible to distinguish patients with different levels of consciousness on the basis of resting-state EEG.
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria. Electronic address: y.hoeller@salk.at.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Höller
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Aljoscha
authors.initials: A
authors.lastname: Thomschewski
authors.affiliation: Neuroscience Institute & Center for Neurocognitive Research, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bergmann
authors.affiliation: Neuroscience Institute & Center for Neurocognitive Research, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Department of Psychology & Center for Neurocognitive Research, University of Salzburg, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Kronbichler
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Neuroscience Institute & Center for Neurocognitive Research, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Department of Psychology & Center for Neurocognitive Research, University of Salzburg, Austria.
authors.forename: Julia S
authors.initials: JS
authors.lastname: Crone
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Elisabeth V
authors.initials: EV
authors.lastname: Schmid
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Kevin
authors.initials: K
authors.lastname: Butz
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Höller
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Merano, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Nardone
authors.affiliation: Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg, Paracelsus Medical University, Salzburg, Austria.
authors.forename: Eugen
authors.initials: E
authors.lastname: Trinka
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000503:physiopathology; D003243:Consciousness / Q000145:classification* / Q000502:physiology*; D003937:Diagnosis, Differential; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D018458:Persistent Vegetative State / Q000175:diagnosis* / Q000503:physiopathology; D011336:Probability; D012146:Rest / Q000502:physiology; D060388:Support Vector Machine
keywords: Classification; Coherence; DOC; DTF; GPDC; MCS; VS