Number Connection Test (NCT) and Continuous Reaction Times (CRT) have been used for assessment of encephalopathy in groups of 105 controls, 65 brain damaged patients and 22 patients with hepatic encephalopathy. With the use of NCT, 65% of the patients with cerebral damage could be correctly classified with regard to presence versus absence of brain disease, whereas the use of CRT gave 85% correct classification. With regard to hepatic encephalopathy the CRT was better for classification than NCT; respectively 86% and 64% were correctly classified. The NCT could not separate the patient with brain damage from the patients with hepatic encephalopathy, whereas CRT could classify respectively 95% and 86% correctly. When the tests were performed on five successive days, the NCT scores showed a learning effect, whereas the CRT gave stable measures. This means that the CRT was superior to the NCT for classification purposes.