Combined Scores from the EncephalApp Stroop Test, Number Connection Test B, and Serial Dotting Test Accurately Identify Patients With Covert Hepatic Encephalopathy

Abstract

Background & aims: The EncephalApp Stroop test is a high-sensitivity but low-specificity test that has been used to identify patients with covert hepatic encephalopathy (CHE). We aimed to develop a new strategy to detect CHE, combining EncephalApp Stroop test score with scores from subtests of the psychometric hepatic encephalopathy scoring system (PHES).

Methods: We performed a survey of 569 adult volunteers (229 men) in 9 communities in Shanghai, China, administering the EncephalApp Stroop test to determine the range of scores in the general population. Data from the standard PHES, including the number connection test-A, number connection test-B (NCT-B), line tracing test, serial dotting test (SDT), and digit symbol test, were used as the reference standard for diagnosis of CHE. A combination of the EncephalApp Stroop with subtests of the PHES was used to establish a new strategy for CHE diagnosis. We validated our findings using data from 160 patients with cirrhosis from 5 centers China.

Results: We determined the range of EncephalApp Stroop test scores for the volunteers of different decades of age, education levels, and sexes. Age, education level, and sex were independently associated with EncephalApp Stroop test scores. A combination of scores from the EncephalApp Stroop test, the NCT-B, and the SDT identified patients with CHE with the highest level of accuracy, when the standard PHES was used as the reference standard. A combination of scores of 187 sec for the EncephalApp Stroop test and below -1 for the NCT-B or below -1 for the SDT identified patients with CHE with an area under the curve (AUC) of 0.86, 81.0% sensitivity, and 91.9% specificity, and 87.5% accuracy. In the validation cohort, these cutoff scores identified patients with CHE with an AUC of 0.88, 97.1% sensitivity, 79.3% specificity, and 86.9% accuracy. The average time to calculate this score was 374±140 sec, compared 424±115 sec for the entire PHES.

Conclusion: Scores from the EncephalApp Stroop test, NCT-B, and SDT identify patients with CHE with approximately 87% accuracy, and in a much shorter time than the standard PHES. This score combination could be a valid and convenient method for identifying patients with CHE. chictr.org.cn number, ChiCTR-EDC-17012007, ChiCTR1800019954.

Keywords: Cirrhosis; Covert Hepatic Encephalopathy; Psychometric Hepatic Encephalopathy Score; Stroop Test.