Auditory and visual P300 event-related potentials to detect minimal hepatic encephalopathy.

INTRODUCTION Diagnosis of Minimal hepatic encephalopathy (MHE) requires psychometric tests, although new methods are needed since sensitivity, specificity, and accuracy are low. The P300 event-related potential (ERP) is obtained by auditory and visual stimuli, although only the auditory P300 has been used to detect MHE. We aimed to compare the diagnostic features of auditory and visual P300 to detect MHE. MATERIALS AND METHODS Sixty patients with liver cirrhosis and thirty-five healthy controls completed the Psychometric Hepatic Encephalopathy Score (PHES), the critical flicker frequency (CFF), auditory, and visual P300. MHE was diagnosed if PHES and CFF scores were abnormal. RESULTS Fifty-three cirrhotic patients (age 54.5±8.6 years) completed all tests. Abnormal scores were: PHES (49.1%), CFF (67.9%). The proportion of MHE was 21.4%. The area under the receiver operating ROC curves (AUROC) for auditory P300 was better than visual P300 for distinguishing MHE from controls (AUROC 0.792 vs 0.725; p<0.005 for both; accuracy 73.8%vs 70.2%; sensitivity 72.2% both; specificity 74.2 vs 69.7, respectively. Among cirrhotic patients, only auditory P300 was useful to detect MHE, AUROC 0.723 p<0.05; 77.4% accuracy; 61.1% sensitivity; and 81.8% specificity. CONCLUSIONS The auditory P300 sensitivity, specificity, and accuracy were similar to those of CFF. Our results showed that only auditory P300 is useful to differentiate patients with MHE. Although both modalities, auditory and visual, differentiated patients with cirrhosis from controls, we consider the visual P300 is not suitable for detecting MHE.