Step Activity Monitoring in Boys with Duchenne Muscular Dystrophy and its Correlation with Magnetic Resonance Measures and Functional Performance

Kavya S. Nair, Donovan J. Lott, Sean C. Forbes, Alison M. Barnard, Rebecca J. Willcocks, Claudia R. Senesac, Michael J. Daniels, Ann T. Harrington, Gihan I. Tennekoon, Kirsten Zilke, Erika L. Finanger, Richard S. Finkel, William D. Rooney, Glenn A. Walter, Krista Vandenborne

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Muscles of boys with Duchenne muscular dystrophy (DMD) are progressively replaced by fatty fibrous tissues, and weakness leads to loss of ambulation (LoA). Step activity (SA) monitoring is a quantitative measure of real-world ambulatory function. The relationship between quality of muscle health and SA is unknown in DMD. Objective: To determine SA in steroid treated boys with DMD across various age groups, and to evaluate the association of SA with quality of muscle health and ambulatory function. Methods: Quality of muscle health was measured by magnetic resonance (MR) imaging transverse magnetization relaxation time constant (MRI-T2) and MR spectroscopy fat fraction (MRS-FF). SA was assessed via accelerometry, and functional abilities were assessed through clinical walking tests. Correlations between SA, MR, and functional measures were determined. A threshold value of SA was determined to predict the future LoA. Results: The greatest reduction in SA was observed in the 9- < 11years age group. SA correlated with all functional and MR measures.10m walk/run test had the highest correlation with SA. An increase in muscle MRI-T2 and MRS-FF was associated with a decline in SA. Two years prior to LoA, SA in boys with DMD was 32% lower than age matched boys with DMD who maintained ambulation for more than two-year period. SA monitoring can predict subsequent LoA in Duchenne, as a daily step count of 3200 at baseline was associated with LoA over the next two-years. Conclusion: SA monitoring is a feasible and accessible tool to measure functional capacity in the real-world environment.

Original languageEnglish (US)
Pages (from-to)423-436
Number of pages14
JournalJournal of Neuromuscular Diseases
Volume9
Issue number3
DOIs
StatePublished - 2022

Keywords

  • 10m walk/run test
  • MRI
  • Step activity
  • duchenne muscular dystrophy
  • fat fraction

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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