Inter-rater reliability of mini balance evaluation system test in ambulatory people with multiple sclerosis

Background: Balance deficits are common in people with multiple sclerosis, and accurate measurement of balance using clinical measures is important. This study investigates the inter-rater reliability of the mini Balance Evaluation System test (mini-BESTest) in ambulatory people with multiple sclerosis. Methods: People with multiple sclerosis attending physiotherapy in an acute hospital were invited to take part. Participants gave demographic information and completed the mini-BESTest twice. Raters were experienced and novice physiotherapists. Data were analysed using intraclass correlation coefficients and Bland and Altman analysis. Agreement of individual items were analysed using weighted Kappa. Results: Fifty participants (37 female) had a mean age of 45.73 (5.65) years; 61.5% did not use a walking aid. The mean difference between the raters was 0.27 (Standard deviation: 1.8; 95% confidence interval (CI): -2.5+2.02), which was not significantly different (P= 0.816). The intra class correlation coefficient was 0.98 (95% CI: 0.96-0.99). The standard error of the measures was 1.27, with a minimum detectable change of 3.91. Most items (2-4, 7-10, 12-14) on the mini-BESTest had Kappa values greater than 0.51; item 14 demonstrated complete agreement (k= 1). Percentage agreement for individual questions ranged from 69% to 100%. Conclusions: Agreement between raters was high for the total score and for the majority of individual items. A change greater than 3.9 points on the mini-BESTest is required to be confident that change is not due to measurement error when two raters are used.