Responsiveness of the Test of Basic Motor Skills of Children with Down Syndrome

Abstract

The aim of this study was to examine the responsiveness of the Test of Basic Motor Skills for Children with Down Syndrome (BMS). Forty-one children with Down Syndrome, 3 to 36 months of age, participated in the study. Gross motor skills were assessed three times using the BMS and the Gross Motor Function Measure (GMFM) before and after a baseline period of 2 weeks (T1-T2) and after a period of 16 weeks (T2-T3). Internal and external responsiveness of the BMS was analyzed using Guyatt's Responsiveness Index (GRI) and 2 x 2 repeated measures. Change in BMS scores was compared to change in GMFM scores and parent and physiotherapist ratings of change. The responsiveness of the BMS was large (GRI = 2.55). A significant Time x Age interaction [F(1,37) = 8.87, p < .01] indicated that BMS scores increased more for children <or= 2 years compared with children 2 to 3 years of age. The difference in GRI between the BMS and GMFM was 0.75 (95% CI -0.25-1.75), indicating that the BMS and GMFM did not significantly differ in responsiveness. The Time x Measure interaction was not significant, indicating that the increase in mean BMS and GMFM scores did not differ. Change in BMS scores were correlated with parent ratings of change (r = 0.65, p < .001) but not physiotherapist ratings (r = 0.36, p = .23). The results provide evidence that the BMS is responsive to change in gross motor development in children with Down Syndrome from 3 to 36 months of age.