title: Application of electrophysiologic techniques in poor outcome prediction among patients with severe focal and diffuse ischemic brain injury.
abstract: OBJECTIVE
  To explore various electrophysiologic examinations as predictors for poor outcome in patients with severe ischemic brain injury, by comparing the prognostic ability of EEG, short-latency somatosensory evoked potentials (SLSEP), and brain stem auditory evoked potentials (BAEP).
  
  
  METHODS
  EEG, SLSEP, and BAEP were recorded in 161 patients with severe ischemic brain injuries (Glasgow Coma Scale ≤ 8), 77 with anoxic-ischemic encephalopathy after cardiopulmonary resuscitation, while 84 experienced massive hemispheric infarction at between 1 and 7 days after the onset. Outcomes were reviewed after 6 months using the Glasgow Outcome Scale.
  
  
  RESULTS
  Six months after the onset, poor outcomes (Glasgow Outcome Scale, 1-2) were identified in 66 and 54 patients among the anoxic-ischemic encephalopathy and the massive hemispheric infarction group, respectively. By using the prognostic authenticity analysis of predictors, unfavorable EEG patterns, lack of EEG reactivity, pathologic N20 of SLSEP, and pathologic wave V of BAEP showed the high sensitivity (92.4%-97.0%, 95% confidence interval [CI]: 82.5%-99.5%), while bilateral absence of SLSEP N20 showed the highest specificity (100%, 95% CI: 67.9%-100%) and positive predictive value (100%, 95% CI: 90.4%-100%) in the anoxic-ischemic encephalopathy group. In the massive hemispheric infarction group, unfavorable EEG patterns showed the highest sensitivity (96.3%, 95% CI: 86.2%-99.4%) while bilateral absence of SLSEP N20 and BAEP wave V showed the highest specificity (100%, 95% CI: 85.9%-100%) and positive predictive value (100%, 95% CI: 80.8%-100%).
  
  
  CONCLUSIONS
  The predictive power of electrophysiologic examinations is different according to the etiology of ischemic brain injury. Short-latency somatosensory evoked potentials (N20) can be considered the most powerful method to predict poor outcome in anoxic-ischemic encephalopathy. Combination of EEG (unfavorable EEG patterns) and SLSEP (N20)/BAEP (wave V) is best suited in massive hemispheric infarction to predict poor outcome.
authors.affiliation: Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Ying Y
authors.initials: YY
authors.lastname: Su
authors.forename: Walter F
authors.initials: WF
authors.lastname: Haupt
authors.forename: Jing W
authors.initials: JW
authors.lastname: Zhao
authors.forename: Shu Y
authors.initials: SY
authors.lastname: Xiao
authors.forename: Hong L
authors.initials: HL
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Pang
authors.forename: Qing L
authors.initials: QL
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000503:physiopathology*; D058256:Brain Waves; D016887:Cardiopulmonary Resuscitation / Q000009:adverse effects*; D002544:Cerebral Infarction / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D016009:Chi-Square Distribution; D002681:China; D004569:Electroencephalography; D016057:Evoked Potentials, Auditory, Brain Stem; D005073:Evoked Potentials, Somatosensory; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011930:Reaction Time; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D055815:Young Adult