Lack of Standardization of the Level of Encephalopathy on EEG: a Barrier to the Widespread Use of EEG for Brain Monitoring

Objective: Lack of consensus on standardized approaches to electroencephalogram (EEG) background analysis and reporting of the overall degree of encephalopathy limits the use of continuous monitoring in the assessment of severity of brain dysfunction. Thus, we sought to demonstrate practice variability in reporting encephalopathy grades of EEG. Background: The widespread use of EEG beyond seizure detection has unveiled its additional utility as a continuous monitoring method for the detection of focal and diffuse brain dysfunction, and in neuroprognostication. However, no consensus exists to guide electroencephalographers in determining the degree of brain dysfunction. Design/Methods: A web-based survey (Qualtrics®) was disseminated to Critical Care EEG Monitoring Research Consortium (CCERMC) participants by the American Clinical Neurophysiology Society (ACNS) in 2017. Following consent, respondents answered 12 background questions about their training and practice, and then graded 40 EEG segments (15-second epoch depicting patients’ most stimulated state) for their degree of cerebral dysfunction. Fleiss Kappa was used for inter-rater agreement (IRA) assessment. Results: 110 responses were obtained; approximately half of respondents had passed the CCERMC nomenclature certification test (52.1%, n=49). The majority of respondents were attendings (78.2%, n=86), and nearly 83% agreed that a standardized approach to grading EEG level of brain dysfunction is needed. The overall IRA of EEG epoch was fair (k=0.32), regardless of level of training (attendings k=0.30, fellows k=0.32). No EEG epoch achieved perfect agreement despite depicting extremes (from normal to severe brain dysfunction). Having CCEMRC nomenclature certification did not improve IRA (k=0.26). Conclusions: We demonstrated the current lack of uniformity and the widespread desire for an encephalopathy grading scale to aid consensus EEG interpretation. The ACNS standardized critical care EEG terminology has facilitated the understanding of rhythmic and periodic patterns. Broadening the terminology in future revisions to include an encephalopathy grading scale may be useful in reducing variability in reporting levels of cerebral dysfunction. Disclosure: Dr. Maciel has nothing to disclose. Dr. Sternberg has nothing to disclose. Dr. Desai has nothing to disclose. Dr. Baron-Lee has nothing to disclose. Dr. Rampal has nothing to disclose. Dr. Hirsch has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Adamas, Aquestive, Ceribell, Eisai, and Neuropace. Dr. Hirsch has received research support from Eisai, Monteris and Upsher-Smith. Dr. Gilmore has nothing to disclose.