PP09.6 – 2400: Reference values for the three-minute walk test, North Star Ambulatory Assessment and timed tests in typically developing boys aged 2.5–5 years

Objectives Assessing walking capacity (6-minute walk test) is used to evaluate function in ambulant boys with Duchenne muscular dystrophy (DMD) and accepted as primary endpoint in registration directed therapeutic studies. The feasibility may be tackled by short attention span or developmental delay in younger children. Therefore a shorter 3 minute walking test (3MWT) is a potentially useful tool for the assessment of functional capacity in this age group. This study aimed 1) to generate normative data for the 3MWT test, the North Star Ambulatory Assessment (NSAA) and timed tests in young typically developing boys between 2.5 and 5 years of age and 2) to describe the relation between the functional tests and with anthropometric variables. Methods 114 typically developing boys aged 2.5–5.9 years (mean 4.2 years) were recruited across four age sub-categories (2.5- Results The 3MWT was feasible for all participants, more encouragements were needed to keep the attention of the very young ones. The three-minute walk distance (3MWD) increased significantly with age, from 160.4m ± 18.8m at 2.5 years to 209.7m ± 19.1m at 5 years. Median score and interquartile range (IQR) on the NSAA increased with age from 25 (23–27) at 2.5 years to 33 (33–34) at 5 years. For the timed tests (Gower's test, 10 m run and climb and descend four stairs), median values (IQR) for the total group were 2.6 (2.2–3.3), 4.1 (3.7–4.7), 2.3 (1.9–3.0) and 2.6 (2.1–3.7) respectively. The correlation coefficient between 3MWT and NSAA was 0.57. High correlations were found between all timed tests. Correlations with age, height and weight varied between 0.56 and 0.79. Conclusion Reference data of the 3MWT, NSAA and timed tests, according to age and height, provide a useful tool in the assessment of functional capacity in boys aged 2.5 to 5 years.