Efforts are currently aimed to find a simplified psychometric performance test battery for the diagnosis of minimal HE in patients with cirrhosis. ImPACT (Immediate Post-concussion Assessment and Cognitive Testing) is a short, user-friendly, internet-based neuropsychological test battery that includes 6 modules resulting in 4 composite scores: verbal memory, visual memory, visual motor speed, and reaction time. In this case control study, the authors compared the ability of ImPACT with traditional testing (paper-and-pencil tests [PPT]), which included number connection A and B tests and DSTs to evaluate patients at risk for minimal HE versus a control cohort of healthy volunteers.
Included in this study were 90 patients (mean age, 54.3 years; male, 69%) with cirrhosis (MELD, 10.39±3.42) and no evidence of overt HE, and 131 age-, gender-, and education-matched controls that were free of liver disease and otherwise healthy. Patients and controls were compared on traditional PPT and the 4 ImPACT composite scores. Participants were excluded from the study if they were currently using treatments applicable to overt HE or sedatives, narcotics, or anti-depressants. A positive PPT score was defined by a score 2 standard deviations below the normative mean on 1 or less PPT. A patient was determined to have a positive ImPACT score if their score was 2 standard deviations from the control mean.
Among the 90 patients at risk for minimal HE, 16 had a positive PPT, and 25 had a positive ImPACT score. Compared with controls, patients had worse scores on 3 of 4 ImPACT composite scores (Table 4). Patients who had a positive PPT also performed worse on ImPACT compared with patients who had a negative PPT (P<.05; Table 5). PPT and ImPACT scores were significantly correlated. The ImPACT visual motor speed composite score had the highest correlation: number connection test A (r=-0.46), number connection test B (r=-0.54), and the DST (r=0.70).
Based on these data, the study authors concluded that ImPACT is a simple and effective tool for the evaluation of psychometric performance and offers a potentially new standard for diagnosing minimal HE.