Diagnostic accuracy between readers for identifying electrographic seizures in critically ill adults

• Type of Material: Article
• Authors: Bin Tu, Columbia University; G. Bryan Young, London Health Sciences Center; Agnieszka Kokoszka, St. Luke's‐Roosevelt‐Mount Sinai Hospital; Andres Rodrigues Ruiz, Emory University; Jay Varma, Barrow Neurological Institute; Linda M. Eerikäinen, GE Healthcare; Nadege Assassi, New York University; Stephan Mayer, Icahn School of Medicine at Mount Sinai; Jan Claassen, Columbia University; Mika O.K. Särkelä, GE Healthcare
• Language: English
• Date: 2017-03
• Publisher: Wiley
• Publication Version: Final Published Version
• Copyright Statement: © 2016 The Authors.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1002/epi4.12034
• Title of Journal or Parent Work: Epilepsia Open
• ISSN: 2470-9239
• Volume: 2
• Issue: 1
• Start Page: 67
• End Page: 75
• Keywords: Interreader agreement; Epilepsy; Critical care; Continuous EEG monitoring; Equivocal seizures
• Research Categories: Health Sciences, General; Biology, Neuroscience

Abstract

Electrographic seizures in critically ill patients are often equivocal. In this study, we sought to determine the diagnostic accuracy of electrographic seizure annotation in adult intensive care units (ICUs) and to identify affecting factors. Methods: To investigate diagnostic accuracy, interreader agreement (IRA) measures were derived from 5,769 unequivocal and 6,263 equivocal seizure annotations by five experienced electroencephalogram (EEG) readers after reviewing 74 days of EEGs from 50 adult ICU patients. Factors including seizure equivocality (unequivocal vs. equivocal) and laterality (generalized, partial, or bilaterally independent), cyclicity (cyclic vs. noncyclic), persistency (occurrence of status epilepticus), and patient consciousness level (coma vs. noncoma) were further investigated for their influence on IRA measures. Results: On average, 70% of seizures marked by a reference reader overlapped, at least in part, with those marked by a test reader (any-overlap sensitivity, AO-Sn). Agreed seizure duration between reader pairs (overlap-integral sensitivity, OI-Sn) was 62%, while agreed nonseizure duration (overlap-integral specificity, OI-Sp) was 99%. A test reader would annotate one additional seizure not overlapping with a reference reader's annotation in every 11.7 h of EEG, that is, the false-positive rate (FPR) was 0.0854/h. Classifying seizure patterns into unequivocal and equivocal improved specificity and FPR (unequivocal patterns) but compromised sensitivity only for equivocal patterns. Sensitivity of all and unequivocal annotations was higher for patients with status epilepticus. Specificity was higher for partial than for bilaterally independent unequivocal seizure patterns, and lower for cyclic all seizure patterns. Significance: Diagnosing electrographic seizures in critically ill adults is highly specific and moderately sensitive. Improved criteria for diagnosing electrographic seizures in the ICU are needed.