Assessing Physical Activity Using Accelerometers in Youth with Duchenne Muscular Dystrophy

Area of Science:

• Neurology
• Physical Therapy
• Biomedical Engineering

Background:

• Physical activity is a proposed outcome measure for Duchenne muscular dystrophy (DMD) patients.
• Limited research exists on quantifying physical activity in DMD using accelerometers.

Purpose of the Study:

• To assess the amount and patterns of physical activity in DMD patients.
• To compare physical activity levels between DMD patients and healthy controls.

Main Methods:

• Used wrist- and ankle-worn accelerometers to measure physical activity in 49 DMD patients and 15 healthy controls.
• Quantified activity by converting recordings to acceleration estimates (counts/min).
• Categorized activity into sedentary, low-intensity, and moderate-to-vigorous, with subcategories for sedentary and low-intensity activities.

Main Results:

• DMD patients spent 98.8% of their daytime in sedentary and low-intensity activities.
• Activity levels were lower in DMD patients compared to controls, and lower in non-ambulatory than ambulatory patients.
• Ambulatory patients' activity levels were similar to controls, and activity was affected by age and ambulation status, but not corticosteroid use.

Conclusions:

• Duchenne muscular dystrophy patients primarily engage in sedentary and low-intensity activities.
• Detailed subcategorization of sedentary and low-intensity activities enhances characterization of activity patterns in DMD.
• Ambulation status and age are key factors influencing physical activity in DMD, while corticosteroid use is not.