One Year Outcome of Boys With Duchenne Muscular Dystrophy Using the Bayley-III Scales of Infant and Toddler Development

BACKGROUND: The pathogenesis of Duchenne muscular dystrophy starts prior to birth. Despite this, clinical trials exclude young boys because traditional outcome measures rely on cooperation. We recently used the Bayley-III Scales of Infant and Toddler Development to study 24 infants and boys with Duchenne muscular dystrophy. Clinical evaluators at six centers were trained and certified to perform the Bayley-III. Here we report six and twelve month follow-up of two subsets of these boys. PATIENTS: Nineteen boys (1.9 ± 0.8 years) were assessed at baseline and six months. Twelve boys (1.5 ± 0.8 years) were assessed at baseline, six, and twelve months. RESULTS: Gross motor scores were lower at baseline compared to published controls (6.2 ± 1.7; normal 10 ± 3; p<.0001), and showed a further declining trend to 5.7 ± 1.7 (p =.20) at six months. Repeated measures analysis of the 12 boys followed for 12 months showed that gross motor scores, again low at baseline (6.6 ± 1.7; p<.0001), declined at six months (5.9 ± 1.8) and further at 12 months (5.3 ± 2.0) (p=0.11). Cognitive and language scores were lower at baseline compared to normal children (range p=.002 to p<0.0001) and did not change significantly at 6 or 12 months (range p=.89 to p=.09). Fine motor skills, also low at baseline, improved over one year (p=.05). CONCLUSION: Development can reliably be measured in infants and young boys with DMD across time using the Bayley-III. Power calculations using these data show that motor development may be used as an outcome measure