Validation of the Simplified Animal Naming Test As Primary Screening Tool for the Diagnosis of Covert Hepatic Encephalopathy

Background: Diagnosis of covert hepatic encephalopathy (CHE) is time consuming in clinical practice. Recently, a new diagnostic tool - the simplified Animal Naming Test (S-ANT1) - was presented with promising results in an Italian cohort. The aim of the present study was to validate S-ANT1 in a cohort of cirrhotic patients from a German tertiary referral centre.

Methods: 143 cirrhotic patients and 37 healthy controls were enrolled. Hepatic encephalopathy (HE) grade 1 (HE1) was clinically diagnosed according to the West-Haven Criteria. Critical flicker frequency and Psychometric Hepatic Encephalopathy Score were used to detect minimal HE (MHE). All participants were additionally examined by S-ANT1.

Results: 58 (40.6%) patients presented with CHE (40 MHE, 18 HE1). S-ANT1 was lowest in patients with HE1, followed by patients with MHE, patients without CHE, and healthy controls, respectively (each p < 0.05). Naming <20 animals discriminated best between patients with and without CHE in ROC analysis (with Youden's index). With a cut-off value of ≥23 mentioned animal names further testing for CHE could be avoided in 38.5% of patients with a negative predictive value of 84%.

Conclusions: S-ANT1 may become an important first screening tool for the assessment of CHE in clinical practice.