The spontaneous EEG, pattern reversal VEPs, and the P300 wave were studied in patients with liver cirrhosis and early stages of hepatic encephalopathy (HE). The sensitivities of the different neurophysiological methods in the early stages of hepatic encephalopathy were compared with each other and with several neuropsychological tests. P300 latency was shown to be the most appropriate neurophysiological method for detection of early HE. The diagnostic sensitivity of the P300 latency resembled that of the number connection test (NCT). These results are discussed with regard to methodological considerations and the clinical use of both methods.