Introduction: The Six-Minute Walk Test (6MWT) was adopted as a clinical outcome measure for ambulatory spinal muscular atrophy (SMA). However, a systematic review of measurement properties reported significant variation among chronic pediatric conditions. Our purpose was to assess the reliability/validity of the 6MWT in SMA.
Methods: Thirty participants performed assessments, including the 6MWT, strength, and function. Reproducibility was evaluated by intraclass correlation coefficients. Criterion/convergent validity were determined using Pearson correlation coefficients.
Results: Test-retest reliability was excellent. The 6MWT was associated positively with peak oxygen uptake, Hammersmith Functional Motor Scale Expanded (HFMSE), lower extremity manual muscle testing, knee flexion hand-held dynamometry, and inversely with 10-m walk/run. The 6MWT discriminates between disease severity, unlike the HFMSE.
Conclusions: This study documents measurement properties of reproducibility, positive criterion validity, and convergent validity with established clinical assessments and reaffirms the value of the 6MWT as a pivotal outcome measure in SMA clinical trials. Muscle Nerve 54: 836-842, 2016.
Keywords: Six-Minute Walk Test; clinical trials; outcome measure; reliability; spinal muscular atrophy; validation.
© 2016 Wiley Periodicals, Inc.