Gastroenterology

Gastroenterology

Volume 135, Issue 5, November 2008, Pages 1591-1600.e1
Gastroenterology

Clinical—Liver, Pancreas, and Biliary Tract
Inhibitory Control Test for the Diagnosis of Minimal Hepatic Encephalopathy

https://doi.org/10.1053/j.gastro.2008.07.021Get rights and content

Background & Aims

Minimal hepatic encephalopathy (MHE) is difficult to diagnose. The Inhibitory Control Test (ICT) measures response inhibition and has diagnosed MHE with 90% sensitivity and specificity in a selected population; high lure and low target rates indicated poor ICT performance. We studied the reliability and validity of ICT for MHE diagnosis.

Methods

ICT was compared with a psychometric battery (standard psychometric tests [SPT]) for MHE diagnosis and overt hepatic encephalopathy (OHE) prediction. ICT was administered twice for test-retest reliability, before/after transvenous intrahepatic portosystemic shunting (TIPS), and before/after yogurt treatment. The time taken by 2 medical assistants (MA) to administer ICT was recorded and compared with that of a psychologist for cost analysis.

Results

One hundred thirty-six cirrhotic patients and 116 age/education-matched controls were studied. ICT (>5 lures) had 88% sensitivity for MHE diagnosis with 0.902 area under the curve for receiver operating characteristic. MHE-positive patients had significantly higher ICT lures (11 vs 4, respectively, P = .0001) and lower targets (92% vs 97%, respectively, P = .0001) compared with MHE-negative patients. The test/retest reliability for ICT lures (n = 50, r = 0.90, P = .0001) was high. ICT and SPT were equivalent in predicting OHE (21%). ICT lures significantly worsened after TIPS (n = 10; 5 vs 9, respectively; P = .02) and improved after yogurt supplementation (n = 18, 10 vs 5, respectively; P = .002). The MAs were successfully trained to administer ICT; the time required for test administration and the associated costs were smaller for ICT than for SPT.

Conclusions

ICT is a sensitive, reliable, and valid test for MHE diagnosis that can be administered inexpensively by MAs.

Section snippets

Patients and Methods

Outpatients with cirrhosis were recruited between September 2004 and December 2007 through clinical referral. Patients between ages 18 and 65 years, without current psychoactive drug use, not on OHE treatments, without history of OHE, and without alcohol use within 3 months were included.

Cross-Sectional Study of the SPT and ICT for Diagnosing MHE

Within the cirrhotic patients, there were 8 patients between 18 and 35 years, 67 between 36 and 55 years, and 48 patients between 56 and 65 years of age. Of the 116 controls, 23 were between 18 and 35 years, 66 between 36 and 55 years, and 27 between 56 and 65 years of age.

Discussion

The current study demonstrates that the ICT is simple to administer and has a high sensitivity, area under the curve for diagnosis, and test-retest reliability for the diagnosis of MHE compared with SPT. ICT has external validity for MHE because it predicts OHE development, improves after successful MHE therapy, and worsens after TIPS placement. This study also demonstrates that ICT can be administered in clinics by MAs after a single training session, which makes ICT a less expensive method

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    Supported in part by GCRC grant number M01-RR00058 and by the New Investigator Research Affairs Committee grant at the Medical College of Wisconsin (to J.S.B.).

    The authors disclose no conflicts.

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