title: Early prediction of delayed cerebral ischemia in subarachnoid hemorrhage based on quantitative EEG: A prospective study in adults.
abstract: OBJECTIVE
  Delayed cerebral infarction (DCI) has a significant impact on mortality and morbidity of patients with subarachnoid hemorrhage (SAH). The aim of this study was to define quantitative EEG (qEEG) parameters for the early and reliable prediction of DCI and compare the validity and time course of qEEG to standard procedures.
  
  
  METHODS
  12 consecutive unselected SAH patients (8 female, mean age 52 years, Hunt-and-Hess grade I-IV) were prospectively examined. Continuous six channel EEG monitoring was started within 48 h after admission (mean duration 5.2 days; range: 2-12 days). All raw and unselected EEG signal underwent automated artifact rejection, Short Time Fast Fourier Transformation and a detrending procedure in order to analyze regional spectral power changes in different frequency bands. According to clinical standards, transcranial Doppler sonography (TCD) was performed at least on alternate days and repeat cerebral computer tomography (CCT) as needed.
  
  
  RESULTS
  6 patients (50%) developed vasospasm/DCI. Decrease of ⩾40% in power persisting over ⩾5h in the alpha band and ⩾6h in the theta band marked the optimal cut-off to detect DCI (sensitivity 89%, specificity 77% for alpha). EEG changes preceded detection of vasospasm/DCI in standard procedures by 2.3d ays. Changes in the beta and delta band as well as in the alpha/delta ratio demonstrated lower correlation with imminent DCI.
  
  
  CONCLUSIONS
  Focal reduction in alpha power may represent a valid, observer independent, non-invasive and continuous marker for vasospasm/DCI in SAH patients.
  
  
  CONCLUSIONS
  qEEG indicates imminent ischemia earlier than established diagnostic tools, such as TCD.
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany. Electronic address: stephanie.gollwitzer@uk-erlangen.de.
authors.forename: S
authors.initials: S
authors.lastname: Gollwitzer
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany; Department of Psychiatry, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Groemer
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Rampp
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hagge
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Olmes
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: H B
authors.initials: HB
authors.lastname: Huttner
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schwab
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Madžar
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Hopfengaertner
authors.affiliation: Department of Neurology, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.
authors.forename: H M
authors.initials: HM
authors.lastname: Hamer
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001921:Brain / Q000503:physiopathology*; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D042241:Early Diagnosis; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000503:physiopathology
keywords: Delayed cerebral ischemia; Quantitative EEG; Subarachnoid hemorrhage; Vasospasm