Can Quantitative Muscle Strength and Functional Motor Ability Differentiate the Influence of Age and Corticosteroids in Ambulatory Boys with Duchenne Muscular Dystrophy?

Conclusion The baseline data analysis of this natural history study indicates that the outcomes measures utilized in this study were sensitive to the age related differences in strength and motor function that are characteristic of disease progression boys with DMD; however treatment effects were less likely to be identified. These findings reflect the difficulty inherent in obtaining the statistical power needed to substantiate intervention efficacy in the small, heterogeneous samples sizes that are characteristic of DMD clinical studies. Isokinetic dynamometry revealed variability in the muscles affected, which has been corroborated with magnetic resonance imaging (MRI) of thigh muscle tissue,32 with significant muscle weakness present in lower extremity muscle groups at an early age. Most informative was the sensitivity of the GMFM dimensions to age and disease related changes in muscle strength and resultant motor skill performance in this cohort, specifically the select motor skills that offer the potential to be sensitive indicators of early disease progression, and thus probable indicators of intervention efficacy. The differences seen in the relationship between muscle group strength and motor skill performance for boys on corticosteroid therapy versus those who are naïve indicates further study is needed to determine the compensatory strategies (i.e. muscular, postural, etc.) employed to preserve functional ability with decrements in muscle strength. Analysis of the...
Source: PLOS Currents Muscular Dystrophy - Category: Neurology Authors: Source Type: research