The effect of flumazenil on visual event-related potentials of clinically non-encephalopathic patients with cirrhosis.

The effects of flumazenil on the latencies and amplitudes of visual event-related potentials (ERPs), number-connection test (NCT) and visual and auditory reaction times (VRT and ART) were evaluated in ten patients with cirrhosis without clinically overt encephalopathy (HE). Delayed latencies of the ERP component P3a and/or P3b were found in three patients and the time to complete NCT was prolonged in two other patients. Changes in the latencies and amplitudes of the ERP components (N200, P3a and P3b) during 40 min following infusion of flumazenil (1 mg) and placebo were similar. Results of the three psychometric tests did not change significantly after either flumazenil or placebo infusion. Eight of the ten patients felt more alert for several minutes after the administration of flumazenil, whereas no patient experienced any change of perception after infusion of placebo. Prolongation of the latencies of P3a and P3b may be a component of the syndrome of subclinical HE. However, these neuro-electrophysiological abnormalities in cirrhotic patients may not be attributable to increased brain levels of natural benzodiazepines.