The visual evoked potential in clinical hepatic encephalopathy in acute and chronic liver disease.

Flash visual evoked potentials were measured in 19 patients with chronic liver disease and in 19 patients with acute hepatic damage secondary to paracetamol overdose with and without clinical hepatic encephalopathy. The flash visual evoked potential showed a series of changes which correlated with the clinical grade and the delta activity of the electroencephalogram in chronic liver disease, and with the delta activity of the electroencephalogram but not with the clinical grade in acute hepatic damage. The changes observed in the flash visual evoked potential in the encephalopathy of chronic liver disease were different from those seen in the corresponding clinical grade of acute hepatic damage, suggesting different pathogenetic mechanisms for encephalopathy in these two conditions.