Inhibitory Control Test, Critical Flicker Frequency, and Psychometric Tests in the Diagnosis of Minimal Hepatic Encephalopathy in Cirrhosis

BACKGROUND/AIM: Minimal hepatic encephalopathy (MHE) impairs health-related quality of life and driving ability of the patient. OBJECTIVE: We assessed the utility of the inhibitory control test (ICT), critical flicker frequency (CFF), and psychometry in the diagnosis of MHE. PATIENTS AND METHODS: Consecutive patients with cirrhosis underwent number connection tests A and B (NCT-A, B), digit symbol test (DST), line tracing test (LTT), serial dot test (SDT), CFF, and ICT at baseline and after four hours. Fifty healthy subjects served as controls for the ICT test. RESULTS: Fifty patients with cirrhosis (43.4 ± 10.2 yrs, M: F 42:8) underwent psychometric tests [NCT-A (48.3 ± 17.7 vs. 42.6 ± 17.3 sec, P = 0.001), NCT-B (85.7 ± 40.1 vs. 90.2 ± 37.0 sec, P = 0.18), DST (23.5 ± 9.3 vs. 23.0 ± 8.7, P = 0.45), LTT (96.6 ± 48.2 vs. 96.8 ± 46.8 sec, P = 0.92), SDT (88.0 ± 39.5 vs. 83.4 ± 37.2 sec, P = 0.02)] at baseline and after four hours. Target accuracy of ICT was lower in patients with cirrhosis compared with controls (88.4 ± 5.6 vs. 95.6 ± 2.1, P = 0.01), whereas ICT lures were higher (18.3 ± 4.2 vs 10.2 ± 2.8, P = 0.01). Patients with cirrhosis showed a reduction in lures in the second evaluation compared with the first (18.3 ± 4.2 vs. 17.1 ± 4.3, P = 0.003) but no change in target accuracy (88.4 ± 5.6 vs. 88.4 ± 5.3, P = 0.97). Control subjects did not show any change either in lures (10.2 ± 2.8 vs. 10.3 ± 2.1, P = 0.65) or target accuracy (95.6 ± 2.1 vs. 95.5 ± 2.2, P = 0.82). The sensitivity and specificity of ICT test for the diagnosis of MHE at lure rate >16.5 was 88.5 and 56%, respectively. CFF in patients with MHE (38.4 ± 1.8 vs. 38.6 ± 1.5, P = 0.3) and non MHE (40.6 ± 2.2 vs. 40.8 ± 2.2, P = 0.6) did not show any difference after four hours as in controls (41.9 ± 2.4 vs. 42.1 ± 2.0, P = 0.3). Thirty one (31%) patients preferred psychometric tests, 57 (57%) preferred CFF and only 12 (12%) preferred ICT (P = 0.001). CONCLUSIONS: ICT, CFF, and psychometric tests are useful tools to assess MHE, and CFF was preferred by this study cohort.