Longitudinal community walking activity in Duchenne muscular dystrophy

INTRODUCTION: Natural history studies for Duchenne muscular dystrophy (DMD) have not included measures of community ambulation. METHODS: Step activity (SA) monitors quantified community ambulation in 42 boys (ages 4-16 years) with DMD with serial enrollment up to 5 years by using a repeated-measures mixed model. Additionally, data were compared with 10-meter walk/run (10mWR) speed to determine validity and sensitivity. RESULTS: There were significant declines in average strides/day and percent strides at moderate, high and pediatric high rates as a function of age (P < 0.05). Significant correlations for 10mWR versus high and low stride rates were found at baseline (P < 0.05). SA outcomes were sensitive to change over 1 year, but the direction and parameter differed by age group (younger vs. older). Changes in strides/day and percentages of high frequency and low frequency strides correlated significantly with changes in 10mWR speed (P < 0.05). DISCUSSION: Community ambulation data provide valid and sensitive real-world measures that may inform clinical trials. Muscle Nerve 57: 401-406, 2018.