[Hepatic encephalopathy: neuropsychological and neurophysiological diagnosis]

Hepatic encephalopathy (HE) is a metabolically induced, potentially reversible functional disorder of brain, that may occur during chronic and acute liver diseases. It is of special clinical relevance to identify latent or subclinical HE, when patients show no clinical signs, but exhibit changes of complex cerebral functions as well as subcortical psychomotor deficits in psychometric tests. Because patients experience significant limitations in everyday life and the presence of such deficits is of prognostic value concerning their life expectancy, detection of latent HE has clinical importance. Psychometric tests have gained most significance because they are easy to perform and demonstrate high sensitivity, being highest with the trail-making-test part B. Electrophysiological methods such as EEG, visual evoked potentials, and P300 currently have a secondary and complementary role. An integration of brain imaging and spectroscopic techniques, electrophysiological methods, and neuropsychological tests is necessary for a comprehensive description of the disturbance on functional and topographical level in the future.