Hepatic encephalopathy evaluated by automatic period analysis of the electroencephalogram during lactulose treatment.

Eleven patients with liver cirrhosis and operative portacaval shunts have been followed clinically and by automatic period analysis of the EEG to study the effects of lactulose on the cerebral manifestations of liver disease. In three patients disturbances of consciousness of hepatic coma character were relieved, manifested by an increase of the dominant EEG frequency and a shift in the frequency spectrum towards normal. The improvement was evident within two to five days and was maintained for two days after withdrawal. Eight patients with varying degrees of intellectual impairment, but without disturbances of consciousness, did not improve and the EEG analysis was unchanged except in one with a subnormal dominant frequency. Thus patients with hepatic encephalopathy manifested by disturbances of consciousness and reduction in the dominant EEG frequency responded to lactulose therapy.