Use of ImPACT to Diagnose Minimal Hepatic Encephalopathy: An Accurate, Practical, User-Friendly Internet-Based Neuropsychological Test Battery

Abstract

An effective, user-friendly neurocognitive test to diagnose minimal hepatic encephalopathy (MHE) is needed. Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) is a brief, validated, Web-based, neuropsychological test battery resulting in four composite scores [Verbal Memory (VrbM), Visual Memory, Visual Motor Speed (VMS), Reaction Time (RT)]. We compared ImPACT to traditional paper-and-pencil tests in patients at risk for MHE versus controls. Ninety cirrhotic patients with no history of overt hepatic encephalopathy were compared with 131 controls on standard psychometric tests (SPT) [Trail Making Test-A, Trail Making Test-B, Digit Symbol Test], 4 ImPACT composite scores, and the Sickness Impact Profile (SIP). MHE+ was defined by a score 2 SD below the normative mean on at least one of the SPT. ImPACT (ImP+) scores of patients were defined as 2 SD from the control mean. Cirrhotic patients scored more poorly than controls on 3/4 of ImPACT scores: VrbM (78.88 vs. 71.37, p<0.001), VMS (26.47 vs. 22.68, p<0.001) and RT (0.89 vs. 1.00, p<0.01), as well as on all 3 SPT. Of the 90 cirrhotics, 16 (18%) were MHE+, who performed more poorly (p<0.001) than patients without MHE on VrbM (58.13 vs. 74.19), VMS (16.77 vs. 23.95) and RT (1.24 vs. 0.95). Of the 90 cirrhotics, 25 (27.8%) were ImP+. MHE+ and ImP+ patients had increased SIP scores versus controls (p<0.001). Compared to paper-and-pencil testing, ImPACT provides a brief, user-friendly, neuropsychological evaluation of MHE. ImPACT could become a new standard for MHE diagnosis.