Animal Naming Test – a simple and accurate test for diagnosis of minimal hepatic encephalopathy and prediction of overt hepatic encephalopathy

AIM OF THE STUDY: Minimal hepatic encephalopathy (MHE) is the mildest form in the spectrum of hepatic encepha-lopathy (HE). We compared the usefulness of the Psychometric Hepatic Encephalopathy Score (PHES) and Animal Naming Test (ANT) for the diagnosis of MHE and the prediction of the development of overt episodes of HE. MATERIAL AND METHODS: 103 consecutive patients with liver cirrhosis without overt HE were subjected to PHES and ANT evaluation. The receiver-operating characteristic curve was used to determine the optimum cut-off of the ANT value for the diagnosis of MHE. RESULTS: Thirty-seven (35.9%) patients had MHE as assessed by altered PHES. ANT (< 14) was positive in 36 (34.95%) patients with MHE with a sensitivity of 89.19% and specificity of 95.7%, positive predictive value (PPV) of 91.67%, negative predictive value (NPV) of 94.03% and diagnostic accuracy of 93.20%. The area under the curve for diagnosis of MHE was 0.978 (95% CI: 0.954-1.0). MHE patients had significantly lower ANT as compared to non-MHE patients and controls (10.81 ±0.324 vs. 15.27 ±0.147 vs. 15.78 ±0.192, respectively, p = 0.01). ANT correlated with PHES (r = 0.752, p = 0.001) and also with Child-Pugh (r = –0.408, p = 0.001) and MELD (r = –0.318, p = 0.001) scores. During follow-up, 14 patients in the MHE group and 4 in the non-MHE group developed overt episodes of HE (p = 0.001). CONCLUSIONS: ANT is simple and accurate for the diagnosis of MHE and prediction of overt episodes of HE in patients with cirrhosis and correlates well with the Child-Pugh and MELD scores.