Large inter-rater variability on EEG-reactivity is improved by a novel quantitative method

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  • Christophe Henri Valdemar Duez
  • Mads Qvist Ebbesen
  • Krisztina Benedek, Department of Clinical Neurophysiology, University of Copenhagen, Rigshospitalet, Nordre Ringvej 57, 2600 Glostrup, Denmark. Electronic address: krisztina.benedek@regionh.dk.
  • ,
  • Martin Fabricius, University of Copenhagen
  • ,
  • Mary Doreen Atkins, Department of Clinical Neurophysiology, Zealand University Hospital, 4000 Roskilde, Denmark. Electronic address: mdat@regionsjaelland.dk.
  • ,
  • Sandor Beniczky
  • Troels W Kjaer, Department of Clinical Neurophysiology, University of Copenhagen, Zealand University Hospital, 4000 Roskilde, Denmark. Electronic address: neurology@dadlnet.dk.
  • ,
  • Hans Kirkegaard
  • Birger Johnsen

OBJECTIVE: To assess inter-rater agreement on EEG-reactivity (EEG-R) in comatose patients and compare it with a quantitative method (QEEG-R).

METHODS: Six 30-s stimulation epochs (noxious, visual and auditory) were performed during EEG on 19 neurosurgical and 11 cardiac arrest patients. Six experts analysed EEGs for reactivity using their habitual methods. QEEG-R was defined as present if ≥2/6 epochs were reactive (stimulation/rest power ratio exceeding noise level). Three-months patient outcome was assessed by the Cerebral Performance Category Score (CPC) dichotomized in good (1-2) or poor (3-5).

RESULTS: Agreement among experts on overall EEG-R varied from 53% to 83% (κ: 0.05-0.64) and reached 100% (κ: 1) between two QEEG-R calculators. For the experts, absence of EEG-R yielded sensitivities for poor outcome between 40-85% and specificities between 20-90%, for QEEG-R sensitivity was 40% (CI: 23-68%) and specificity 100% (CI: 69-100%).

CONCLUSIONS: There is a large inter-rater variation among experts on EEG-R assessment in comatose patients. QEEG-R is a promising objective prognostic parameter with low inter-rater variation and a high specificity for prediction of poor outcome.

SIGNIFICANCE: Clinicians should be cautious when using the traditional, qualitative method, in particular in end-of-life decisions. Implementation of the quantitative method in clinical practice may improve reliability of reactivity assessments.

Original languageEnglish
JournalClinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology
Volume129
Issue4
Pages (from-to)724-730
Number of pages7
ISSN1388-2457
DOIs
Publication statusPublished - Apr 2018

    Research areas

  • Coma prognosis, EEG reactivity, Inter-rater variation, Outcome prediction, Quantitative EEG

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