Which outcome measure is appropriate for assessing ambulatory function in children with Duchenne muscular dystrophy aged 3-6 years?

• A. TUG
• B. GMFM-66
• C. PEDI-CED
• D. North Star Ambulatory Assessment

Answer: (D)

Focus on a measure that directly captures how a child with Duchenne moves when they are actually ambulatory. The North Star Ambulatory Assessment is designed specifically for ambulant boys with DMD and assesses real-life walking and related activities across a range of tasks that matter for everyday function.

It includes 17 items that reflect common ambulatory abilities—standing from a chair, walking, running, stair climbing, hopping, turning, and balance tasks. Each item is scored 0 to 2, with a total possible score of 34. A higher score means better ambulatory function. This scale is validated for boys with DMD in early childhood through adolescence and is known to be responsive to small changes over time, making it suitable for detecting progression or treatment effects in a 3- to 6-year-old who is still ambulant.

Other measures are not as appropriate here. The TUG test, while useful for general mobility, is not disease-specific to DMD and may miss subtle, disease-related changes in early ambulatory skills. GMFM-66 is CP-oriented and not tailored to the particular movement patterns of DMD, limiting its sensitivity to DMD-specific changes. PEDI-CED covers broad daily activities but does not target the specific ambulatory tasks most relevant for tracking DMD progression in this age group. The North Star Ambulatory Assessment provides the most relevant, sensitive, and validated snapshot of ambulatory function for young children with Duchenne.