Assessment of Minimal Hepatic Encephalopathy with Brain MRI and EncephalApp Stroop Test

Background: Minimal hepatic encephalopathy (MHE) consists of subtle cognitive deficits that are not apparent on a standard neurological examination. Minimal hepatic encephalopathy has been reported in up to 80% of cirrhotic patients and is associated with decreased job performance, poor driving performance, impaired quality of life, and poor survival. In parallel, brain magnetic resonance imaging (MRI) abnormalities are known to occur in liver cirrhotic patients in the form of T1 globus pallidus hyperintensities. In recent years, a new psychometric test for diagnosing MHE has been developed as an app for smartphones and tablets (EncephalApp Stroop test). A translated version of the app is available in Romanian language. Aim:To use EncephalApp Stroop test for MHE diagnosis in our cirrhotic patients; to describe the main brain MRI abnormalities encountered in these patients; and to establish if Stroop test results correlate with imaging findings, clinical neurologic findings, and liver function parameters or prognosis. Material and methods:Cross-sectional study over a one-year period, involving 30 adult patients with liver cirrhosis. Subjects were evaluated through a standard neurological examination, psychometric testing using EncephalApp Stroop test, electroencephalogram and brain MRI. In parallel, 40 adult healthy controls were also recruited and evaluated with the EncephalApp Stroop test using the same methodology. Results:Age distribution was similar between the two groups (p=0.6). The mean age of patients was 50±10 years and that of controls 51±12 years. Mean Stroop result was 171±26 seconds for the patient group and 143±20 seconds for the control group (p<0.0001). There was a direct correlation between Stroop test results and age in the control group (R=0.69, p<0.0001) but not also in the patient group (R=0.28, p=0.13). Statistically significant results were obtained by using the Fischer exact test for both cut-off values: 145 seconds in patients < 45-year-old (p<0.001) and 190 seconds in those ≥45 years-old (p=0.03). MRI T1-hyperintensities of the basal ganglia, blood ammonia levels and electroencephalographic changes were not associated with poorer results. Conclusion:Our pilot study, although small, confirmed that patients with liver cirrhosis may have subtle deficits in cognitive areas like attention, concentration or reaction time. This can be assessed easily with the EncephalApp Stroop test which is readily available for use on smartphones or tablets.