Inhibitory Control Test for the Diagnosis of Minimal Hepatic Encephalopathy

Division of Gastroenterology, Hepatology, and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia, USA.
Gastroenterology (Impact Factor: 13.93). 08/2008; 135(5):1591-1600.e1. DOI: 10.1053/j.gastro.2008.07.021
Source: PubMed

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

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Available from: Jasmohan Bajaj, Jul 28, 2014
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    • "Taken together, these results indicate that ICT performance can discriminate between patients with and without MHE (cf. Amodio et al. 2010; Bajaj et al. 2008). In this regard, a new and interesting result comes from the evaluation of the performance of patients without MHE. "
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    ABSTRACT: Recent evidence reveals that inter- and intra-individual variability significantly affects cognitive performance in a number of neuropsychological pathologies. We applied a flexible family of statistical models to elucidate the contribution of inter- and intra-individual variables on cognitive functioning in healthy volunteers and patients at risk for hepatic encephalopathy (HE). Sixty-five volunteers (32 patients with cirrhosis and 33 healthy volunteers) were assessed by means of the Inhibitory Control Task (ICT). A Generalized Additive Model for Location, Scale and Shape (GAMLSS) was fitted for jointly modeling the mean and the intra-variability of Reaction Times (RTs) as a function of socio-demographic and task related covariates. Furthermore, a Generalized Linear Mixed Model (GLMM) was fitted for modeling accuracy. When controlling for the covariates, patients without minimal hepatic encephalopathy (MHE) did not differ from patients with MHE in the low-demanding condition, both in terms of RTs and accuracy. Moreover, they showed a significant decline in accuracy compared to the control group. Compared to patients with MHE, patients without MHE showed faster RTs and higher accuracy only in the high-demanding condition. The results revealed that the application of GAMLSS and GLMM models are able to capture subtle cognitive alterations, previously not detected, in patients' subclinical pathologies.
    Metabolic Brain Disease 03/2014; 29(4). DOI:10.1007/s11011-014-9529-0 · 2.40 Impact Factor
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    • "Since hepatic encephalopathy reverses in most patients after appropriate treatment, it is considered a functional disorder [2]. The methodology used to explore cerebral function in cirrhosis includes: the EEG and the mean dominant frequency, neuropsychological tests exploring attention and cognitive functions, and the critical flicker frequency and other recently introduced computerized tests that estimate the reactive ability of the patients to a visual stimulus [3] [4] [5] [6]. Most of these tests have been developed to diagnose minimal hepatic encephalopathy. "
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    Journal of Hepatology 12/2010; 55(3):564-73. DOI:10.1016/j.jhep.2010.12.008 · 10.40 Impact Factor
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    ABSTRACT: Minimal hepatic encephalopathy (MHE) is the mildest form of spectrum of hepatic encephalopathy (HE). Patients with MHE have no recognizable clinical symptoms of HE but have mild cognitive and psychomotor deficits. The prevalence of MHE is high in patients with cirrhosis of liver and varies between 30% and 84%; it is higher in patients with poor liver function. The diagnostic criteria for MHE have not been standardized but rest on careful patient history and physical examination, normal mental status examination, demonstration of abnormalities in cognition and/or neurophysiological function, and exclusion of concomitant neurological disorders. MHE is associated with impaired health-related quality of life, predicts the development of overt HE and is associated with poor survival. Hence, screening all patients with cirrhosis for MHE using psychometric tests, and treatment of those patients diagnosed to have MHE has been recommended. Ammonia plays a key role in the pathogenesis of MHE, which is thought to be similar to that of overt HE. Thus, ammonia-lowering agents such as lactulose and probiotics have been tried. These agents have been shown to improve cognitive and psychometric deficits, and have good safety profile. Future studies will better define the role of other drugs, such as rifaximin, acetyl L-carnitine and L-ornithine L-aspartate.
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