A pilot evaluation of a computer-based psychometric test battery designed to detect impairment in patients with cirrhosis

Abstract

Nicola A Cook,1 Jin Un Kim,1 Yasmin Pasha,1 Mary ME Crossey,1 Adrian J Schembri,2,3 Brian T Harel,2,4 Torben Kimhofer,5 Simon D Taylor-Robinson1 1Liver Unit, Division of Digestive Health, Department of Surgery and Cancer, Imperial College London, London, UK; 2Cogstate, Inc., New Haven, CT, USA; 3Department of Psychology, Royal Melbourne Institute of Technology University, Melbourne, VIC, Australia; 4Child Study Center, Yale University, New Haven, CT, USA; 5Section of Biomolecular Medicine, Division of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, UK Background: Psychometric testing is used to identify patients with cirrhosis who have developed hepatic encephalopathy (HE). Most batteries consist of a series of paper-and-pencil tests, which are cumbersome for most clinicians. A modern, easy-to-use, computer-based battery would be a helpful clinical tool, given that in its minimal form, HE has an impact on both patients’ quality of life and the ability to drive and operate machinery (with societal consequences).Aim: We compared the Cogstate™ computer battery testing with the Psychometric Hepatic Encephalopathy Score (PHES) tests, with a view to simplify the diagnosis.Methods: This was a prospective study of 27 patients with histologically proven cirrhosis. An analysis of psychometric testing was performed using accuracy of task performance and speed of completion as primary variables to create a correlation matrix. A stepwise linear regression analysis was performed with backward elimination, using analysis of variance.Results: Strong correlations were found between the international shopping list, international shopping list delayed recall of Cogstate and the PHES digit symbol test. The Shopping List Tasks were the only tasks that consistently had P values of <0.05 in the linear regression analysis.Conclusion: Subtests of the Cogstate battery correlated very strongly with the digit symbol component of PHES in discriminating severity of HE. These findings would indicate that components of the current PHES battery with the international shopping list tasks of Cogstate would be discriminant and have the potential to be used easily in clinical practice. Keywords: hepatic encephalopathy, minimal hepatic encephalopathy, cirrhosis, psychometric testing, Cogstate™, Psychometric Hepatic Encephalopathy Score

Keywords

• Hepatic encephalopathy
• minimal hepatic encephalopathy
• cirrhosis
• psychometric testing
• CogstateTM
• Psychometric Hepatic Encephalopathy Score (PHES)