Electroencephalographic Grading of Neuronal Dysfunction in Various Etiologies of Encephalopathy

Abstract

Objective: The objective of this work was to study the electroencephalographic (EEG) grading of neuronal dysfunction in encephalopathy of various etiologies and assess their association with clinical outcomes. Subjects and Methods: This retrospective cross-sectional study was performed between June and November 2018 at the Neurology Department of King Fahd Hospital of University, Kingdom of Saudi Arabia (KSA) and involved a review and analysis of EEG and medical records pertaining to 222 patients in whom encephalopathy was diagnosed. Results: In patients suffering from encephalopathy, advanced age ( P = .01), low Glasgow Coma Scale (GCS) scores ( P = .00), and certain etiologies, namely hypoxic-ischemic encephalopathy (HIE) ( P = .00), septic encephalopathy ( P = .01), and other illnesses ( P = .00), were significantly associated with unfavorable clinical outcomes, whereas traumatic brain injury (TBI) ( P = .01) and GCS >7 ( P = .00) were associated with favorable outcomes. Among different etiologies, EEG grade I ( P = .02) and grade IV ( P = .04) neuronal dysfunction was significantly associated with TBI while grade III ( P = .05) and grade V ( P = .02) neuronal dysfunction was significantly associated with HIE. Grade I ( P = .03) neuronal dysfunction was mostly observed in septic encephalopathy cases, while patients suffering from other illnesses were also found to have grade I ( P = .04) and grade IV ( P = .05) neuronal dysfunction based on their EEG. Conclusion: EEG is being conducted routinely to determine the course and severity of various forms of encephalopathy. However, the clinical implications of EEG grading for neuronal dysfunction are largely dependent on underlying etiology and other clinical parameters, such as age and GCS score. Further larger prospective cohort studies involving other important prognostic parameters and continuous EEG monitoring are thus needed.