Hepatic coma: the electroencephalographic pattern.

Recent advances in our knowledge of the neurophysiologic mechanisms underlying sleep and experimental states of coma (1) suggest the need for a neurophysiologic approach to the many complex clinical syndromes associated with disturbance of consciousness. The coma syndrome associated with hepatic disease and usually known as hepatic coma was chosen for investigation since it presents a good example of toxic coma without gross structural change in the brain. The rapid changes in level of consciousness which frequently occur in this syndrome make it particularly susceptible to experimental study. The observations described below represent an effort to analyze such electroencephalographic (EEG) patterns as may be observed in patients with various forms of hepatic disease before, during, and after the clinical state known as hepatic coma.