Related Experiment Video
Updated: Jun 21, 2025
Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy
Published on: January 12, 2019
Meaningful changes in motor function in Duchenne muscular dystrophy (DMD): A multi-center study.
Francesco Muntoni1, James Signorovitch2,3, Gautam Sajeev2
1Dubowitz Neuromuscular Centre, NIHR Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, & Great Ormond Street Hospital Trust, London, United Kingdom.
Researchers determined the minimal detectable change (MDC) for key motor function tests in Duchenne muscular dystrophy (DMD). These benchmarks help confirm if changes in functional measures reflect true progression or variability in ambulatory DMD patients.
Area of Science:
- Neurology
- Genetics
- Clinical Trials
Background:
- Duchenne muscular dystrophy (DMD) is a rare genetic disorder causing progressive muscle wasting.
- Accurate assessment of treatment efficacy in DMD requires understanding the meaningfulness of changes in functional measures.
Purpose of the Study:
- To estimate the minimal detectable change (MDC) for motor function measures in ambulatory DMD patients.
- To establish benchmarks for detecting true underlying changes in motor function, distinguishing them from measurement error or transient variations.
Main Methods:
- MDC was estimated for the North Star Ambulatory Assessment (NSAA), 4-stair climb (4SC) completion time and velocity, and 6-minute walk distance (6MWD).
- Data from over 1000 ambulatory DMD patients (aged 4-17, on steroids) across clinical trials and real-world settings were analyzed.
- Minimal clinically important differences (MCIDs) for worsening were also estimated for comparison.
Main Results:
- MDC thresholds for >80% confidence in true change were established: NSAA (2.8 units), 4SC time (1.3 seconds), 4SC velocity (0.36 stairs/second), and 6MWD (36.3 meters).
- MDC estimates were consistent across different data sources (clinical trials vs. real-world).
- Estimated MDCs were generally slightly larger than MCIDs for these measures.
Conclusions:
- The identified MDC thresholds provide reliable benchmarks for monitoring motor function in ambulatory DMD.
- These thresholds can inform the definition of clinical trial endpoints and aid in assessing individual patient changes.
- Understanding MDC is crucial for evaluating treatment effectiveness in Duchenne muscular dystrophy.
