Electroencephalography in hepatic encephalopathy: diagnostic and prognostic applications across the disease spectrum

Hepatic encephalopathy (HE) represents a neuropsychiatric continuum arising from cirrhosis and portosystemic shunting, where metabolic toxicity, neuroinflammation and impaired cerebral autoregulation progressively disrupt cortical network function. Minimal hepatic encephalopathy (MHE), its first and not overt stage, has been recognized as a major cause of impaired quality of life and has been associated with reduced functioning and heightened risk of progression to overt HE and mortality. Current diagnostic tools, primarily psychometric tests, capture only clinical manifestations, and lack the ability to directly examine neuronal dysfunction. Electroencephalography (EEG) provides a real-time tool to quantify brain activity, allowing the identification of subtle neural alterations long before clinical symptoms appear. Quantitative EEG (qEEG) indices, such as reduced mean dominant frequency, increased slow-wave activity and disrupted spectral ratios, consistently reflect early cognitive impairment in studies, and are correlated with liver disease severity and neurological performance. These markers not only enhance the early diagnosis of MHE, but also carry important prognostic implications: several EEG parameters have independently predicted future progression of the disease, hospitalization and mortality, and may enhance established risk models when integrated into multicomponent indices such as model for end-stage liver disease (MELD)-EEG. Collectively, evidence suggests that EEG could be used as a multidimensional and objective assessment of neural dysfunction that complements psychometric, biochemical, and imaging-based methods. Our study aimed to examine the diverse electrophysiological findings clarifying the diagnostic and prognostic importance of EEG-based markers, and to examine their possible role in early diagnosis, risk stratification and future clinical applications for patients with HE.