Source

Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, Virginia. jsbajaj@vcu.edu.

Abstract

Minimal hepatic encephalopathy (MHE) detection is difficult due to the unavailability of short screening tools. Therefore MHE patients can remain undiagnosed and untreated. Aim: To use a Stroop smartphone application (EncephalApp_Stroop) to screen for MHE. Methods: The App and standard psychometric tests (SPT; 2/4 abnormal is MHE, gold standard), psychometric hepatic encephalopathy score(PHES) and Inhibitory control(ICT) tests were administered to cirrhotics [with/without prior-overt HE(OHE)] and age-matched controls from two centers; a subset underwent re-testing. A separate validation cohort was also recruited. Stroop has "off" state with neutral stimuli and "on" state with incongruent stimuli. Outcomes: time to complete five correct runs, number of trials needed in On(On time) and Off(Off time) states. Stroop results were compared between controls and cirrhotics with/without OHE, and those with/without MHE (using SPT,ICT,PHES). ROC analysis was performed to diagnose MHE in cirrhotics with/without prior OHE. Results: 125 cirrhotics (43 prior OHE) and 134 controls were included in the original cohort. App times were correlated with MELD (Off time :r=0.57,Ontime:r=0.61,p<0.0001) and were worst in prior-OHE patients compared to the rest and controls. Stroop performance was also significantly impaired in those with MHE compared to no-MHE according to SPT, ICT and PHES (all p<0.0001). A cut-off of>274.9seconds(OnTime+OffTime) had an AUC=0.89 in all patients and 0.84in patients without prior OHE for MHE diagnosis using SPT as the gold standard. The validation cohort showed 78% sensitivity and 90% specificity with the >274.9 secondsOnTime+OffTimecut-off. App result patterns were similar between the centers. Test-retest reliability in controls and those without prior OHE was good; a learning effect on Ontime in cirrhotics without prior OHE was seen. In conclusion, the Stroop smartphone app is a short, valid and reliable tool for screening of MHE.