Neurophysiological investigation of hepatic encephalopathy.

The neurophysiological tools used to study hepatic encephalopathy (HE) are the electroencephalogram (EEG) and the evoked potentials (EPs), both exogenous and endogenous. These tools are used (1) to diagnose HE in patients with severe liver disease and mental alteration, (2) to grade overt HE and monitor the effect of treatment for HE, (3) to diagnose minimal HE (4) to predict the occurrence of episodes of overt HE or liver-related death. The rationale for the use of each of these tools together with their theoretical and practical role is reviewed.