title: EEG synchronization measures are early outcome predictors in comatose patients after cardiac arrest.
abstract: OBJECTIVE
  Outcome prognostication in comatose patients after cardiac arrest (CA) remains a major challenge. Here we investigated the prognostic value of combinations of linear and non-linear bivariate EEG synchronization measures.
  
  
  METHODS
  94 comatose patients with EEG within 24h after CA were included. Clinical outcome was assessed at 3months using the Cerebral Performance Categories (CPC). EEG synchronization between the left and right parasagittal, and between the frontal and parietal brain regions was assessed with 4 different quantitative measures (delta power asymmetry, cross-correlation, mutual information, and transfer entropy). 2/3 of patients were used to assess the predictive power of all possible combinations of these eight features (4 measures×2 directions) using cross-validation. The predictive power of the best combination was tested on the remaining 1/3 of patients.
  
  
  RESULTS
  The best combination for prognostication consisted of 4 of the 8 features, and contained linear and non-linear measures. Predictive power for poor outcome (CPC 3-5), measured with the area under the ROC curve, was 0.84 during cross-validation, and 0.81 on the test set. At specificity of 1.0 the sensitivity was 0.54, and the accuracy 0.81.
  
  
  CONCLUSIONS
  Combinations of EEG synchronization measures can contribute to early prognostication after CA. In particular, combining linear and non-linear measures is important for good predictive power.
  
  
  CONCLUSIONS
  Quantitative methods might increase the prognostic yield of currently used multi-modal approaches.
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. Electronic address: frederic.zubler@gmail.com.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Zubler
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Steimer
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Rebekka
authors.initials: R
authors.lastname: Kurmann
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Bandarabadi
authors.affiliation: Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
authors.forename: Jan
authors.initials: J
authors.lastname: Novy
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Heidemarie
authors.initials: H
authors.lastname: Gast
authors.affiliation: Department of Intensive Care Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
authors.forename: Mauro
authors.initials: M
authors.lastname: Oddo
authors.affiliation: Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
authors.forename: Kaspar
authors.initials: K
authors.lastname: Schindler
authors.affiliation: Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
authors.forename: Andrea O
authors.initials: AO
authors.lastname: Rossetti
mesh_terms: D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D003344:Cortical Synchronization; D005260:Female; D006323:Heart Arrest / Q000150:complications* / Q000175:diagnosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015599:Trauma Severity Indices
keywords: Anoxic-ischemic encephalopathy; Prognostication; Quantitative EEG; Synchronization