Longitudinal interaction between muscle impairments and gait pathology in growing children with Duchenne muscular dystrophy

Abstract

Aim: The aim of this longitudinal observational cohort study was to investigate the longitudinal interaction between progressive muscle impairments and progressive gait pathology in growing boys with Duchenne muscular dystrophy (DMD). Methods: Thirty-one boys with DMD (aged 4y7mo-16y5mo), were repeatedly measured between 2015 and 2022, resulting in a total dataset of 152 observations. Fixed dynamometry, goniometry and 3D gait analysis were used to asses lower limb muscle weakness, passive range of motion and gait. Joint random-effects models between gait and muscle impairment outcomes were fitted. The correlation between the random intercepts (ra) and random slopes (rb) indicated the degree to which respectively the starting levels and progression rates over time of two outcomes were related in boys with DMD. Results: Specific muscle impairments were related to specific gait features, in terms of starting levels (ra=0.470-0.757; p<0.029) and progression rates (rb=0.547-0.812; p<0.024). Interpretation: The findings improved insights into how specific muscle impairments may contribute to specific gait features in DMD. This could enhance clinical decision making, advance rehabilitation, orthotic and orthopedic interventions, and reveal sensitive outcome measures to prove the efficacy of novel treatments in clinical trials.