UNIFIED BALANCE SCALE: CLASSIC PSYCHOMETRIC AND CLINICAL PROPERTIES

Objective: To evaluate the classic psychometric and clinical profile of the Unified Balance Scale, a novel Rasch-based measure of balance. Methods: The Unified Balance Scale was administered to 219 neurological patients (providing 302 observations) admitted to rehabilitation, together with: Timed Up & Go, 10-meters walking test, Functional Ambulation Classification (FAC), Walking Handicap Scale, FIM (TM), Trunk Control Test, Motricity Index, and posturographic indexes. Analyses included: concurrent validity, external construct validity (convergent, divergent and discriminant validity), responsiveness, interpretability, predictive validity and usability. Results: External construct validity (e.g. correlation with FAC: rho=0.80; with the motor FIM (TM): rho=0.55), adequate responsiveness (effect size 1.13), interpretability (the relationship of Unified Balance Scale scores with those of the originating scales and, indirectly, with the risk of falling), and, finally, predictive validity (e.g. relative risk of nursing home admission: 4.33 (95% confidence interval 2.43-7.73) for Unified Balance Scale scores <= 2 on admission) were demonstrated for the Unified Balance Scale. Analysis of usability suggested a mean administration time of 20-30 min. Conclusion: Although further studies are needed to generalize these results to different samples, to confirm its fall risk estimation capabilities and to improve its usability, the Unified Balance Scale presents itself as a psychometrically sound outcome measurement tool to evaluate the effectiveness both of fall reduction plans and of rehabilitation interventions aimed at improving balance.