The UK Functional Assessment Measure (UK FIM+FAM): Psychometric Evaluation in Patients Undergoing Specialist Rehabilitation Following a Stroke From the National UK Clinical Dataset

Abstract

The UK Functional Assessment Measure (UKFIM+FAM) is the principal outcome measure for the UK Rehabilitation Outcomes Collaborative (UKROC) national database for specialist rehabilitation. Previously validated in a mixed neurorehabilitation cohort, this study is the first to explore its psychometric properties in a stroke population, and compare left and right hemispheric strokes (LHS vs RHS). We analysed in-patient episode data from 62 specialist rehabilitation units collated through the UKROC database 2010-2013. Complete data were analysed for 1,539 stroke patients (LHS: 588, RHS: 566 with clear localisation). For factor analysis, admission and discharge data were pooled and randomised into two equivalent samples; the first for exploratory factor analysis (EFA) using principal components analysis, and the second for confirmatory factor analysis (CFA). Responsiveness for each subject (change from admission to discharge) was examined using paired t-tests and differences between LHS and RHS for the entire group were examined using non-paired t-tests. EFA showed a strong general factor accounting for >48% of the total variance. A three-factor solution comprising motor, communication and psychosocial subscales, accounting for >69% total variance, provided acceptable fit statistics on CFA (Root Mean Square Error of Approximation was 0.08 and Comparative Fit Index/ Tucker Lewis Index 0.922/0.907). All three subscales showed significant improvement between admission and discharge (p<0.001) with moderate effect sizes (>0.5). Total scores between LHS and RHS were not significantly different. However, LHS showed significantly higher motor scores (Mean 5.7, 95%CI 2.7, 8.6 p<0.001), while LHS had significantly lower cognitive scores, primarily in the communication domain (-6.8 95%CI -7.7, -5.8 p<0.001). To conclude, the UK FIM+FAM has a three-factor structure in stroke, similar to the general neurorehabilitation population. It is responsive to change during in-patient rehabilitation, and distinguishes between LHS and RHS. This tool extends stroke outcome measurement beyond physical disability to include cognitive, communication and psychosocial function.