Delayed developmental language milestones in children with Duchenne's muscular dystrophy.

OBJECTIVES To document the attainment of developmental milestones in children with Duchenne's muscular dystrophy (DMD) and to determine whether early delays are associated with later performance on measures of cognition. STUDY DESIGN Retrospective parental report was utilized to document the acquisition of 10 common developmental milestones in children with DMD (n = 130) and their unaffected siblings (n = 59). Children completed tests of cognitive functioning. RESULTS Parents rated children with DMD as delayed on achieving both language and motor milestones more frequently than their unaffected siblings. Furthermore, those children with DMD who were rated as late talkers or late walkers performed more poorly on tests of cognitive function than their on-time peers. CONCLUSIONS In addition to the commonly reported delays in motor milestones, the current study documents delays in the acquisition of language milestones as well. These early delays are associated with significant impairments in later cognitive functioning.