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Author Notes:

Address correspondence to Nicolas Gaspard, Comprehensive Epilepsy Center,

Conflict of Interest: All authors are members of the CCEMRC. The CCEMRC received infrastructure support from the American Epilepsy Society/Epilepsy Foundation. NG received support from the Epilepsy Foundation. LJH received research support for investigator-initiated studies from UCB-Pharma, Upsher-Smith, and Lundbeck; consultation fees for advising from Lund-beck, Upsher-Smith, GlaxoSmithKline RSC Diagnostics, and NeuroPace; royalties for authoring chapters for UpToDate-Neurology, and for coauthoring the book Atlas of EEG in Critical Care, by Hirsch and Brenner, 2010. SML received research support from UCB and royalties from Demos Publishing. CDH received research support from the Canadian Institutes of Health Research, The Hospital for Sick Children Foundation, and the PSI Foundation. MBW received support from the American Brain Foundation and royalties for coauthoring the book Pocket Neurology, LWW, 2010.



  • Science & Technology
  • Life Sciences & Biomedicine
  • Clinical Neurology
  • Neurosciences & Neurology
  • Continuous EEG monitoring
  • EEG terminology
  • Periodic patterns
  • Rhythmic patterns
  • Interrater agreement
  • Intensive care
  • Critical care
  • PLEDs
  • GPEDs

Interrater agreement for Critical Care EEG Terminology


Journal Title:



Volume 55, Number 9


, Pages 1366-1373

Type of Work:

Article | Post-print: After Peer Review


Objective: The interpretation of critical care electroencephalography (EEG) studies is challenging because of the presence of many periodic and rhythmic patterns of uncertain clinical significance. Defining the clinical significance of these patterns requires standardized terminology with high interrater agreement (IRA). We sought to evaluate IRA for the final, published American Clinical Neurophysiology Society (ACNS)- approved version of the critical care EEG terminology (2012 version). Our evaluation included terms not assessed previously and incorporated raters with a broad range of EEG reading experience. Methods: After reviewing a set of training slides, 49 readers independently completed a Web-based test consisting of 11 identical questions for each of 37 EEG samples (407 questions). Questions assessed whether a pattern was an electrographic seizure; pattern location (main term 1), pattern type (main term 2); and presence and classification of eight other key features ("plus" modifiers, sharpness, absolute and relative amplitude, frequency, number of phases, fluctuation/evolution, and the presence of "triphasic" morphology). Results: IRA statistics (j values) were almost perfect (90-100%) for seizures, main terms 1 and 2, the +S modifier (superimposed spikes/sharp waves or sharply contoured rhythmic delta activity), sharpness, absolute amplitude, frequency, and number of phases. Agreement was substantial for the +F (superimposed fast activity) and +R (superimposed rhythmic delta activity) modifiers (66% and 67%, respectively), moderate for triphasic morphology (58%), and fair for evolution (21%). Significance: IRA for most terms in the ACNS critical care EEG terminology is high. These terms are suitable for multicenter research on the clinical significance of critical care EEG patterns.

Copyright information:

© 2014 International League Against Epilepsy.

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