title: Interrater agreement for Critical Care EEG Terminology.
abstract: 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 (κ 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%).
  
  
  CONCLUSIONS
  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. A PowerPoint slide summarizing this article is available for download in the Supporting Information section http://dx.doi.org/10.1111/epi.12653/supinfo.
authors.affiliation: Department of Neurology, Comprehensive Epilepsy Center, Yale University School of Medicine, New Haven, Connecticut, U.S.A.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Gaspard
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Hirsch
authors.forename: Suzette M
authors.initials: SM
authors.lastname: LaRoche
authors.forename: Cecil D
authors.initials: CD
authors.lastname: Hahn
authors.forename: M Brandon
authors.initials: MB
authors.lastname: Westover
mesh_terms: D000293:Adolescent; D058256:Brain Waves / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003422:Critical Care; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D057566:Self Report; D009626:Terminology as Topic
keywords: Continuous EEG monitoring; Critical care; EEG terminology; GPEDs; Intensive care; Interrater agreement; PLEDs; Periodic patterns; Rhythmic patterns