Original Paper

Journal of Autism and Developmental Disorders

, Volume 37, Issue 1, pp 158-170

First online:

Variation in Vocal-Motor Development in Infant Siblings of Children with Autism

  • Jana M. IversonAffiliated withDepartment of Psychology, University of Pittsburgh Email author 
  • , Robert H. WozniakAffiliated withDepartment of Psychology, Bryn Mawr College

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In this study we examined early motor, vocal, and communicative development in a group of younger siblings of children diagnosed with autism (Infant Siblings). Infant Siblings and no-risk comparison later-born infants were videotaped at home with a primary caregiver each month from 5 to 14 months, with follow-up at 18 months. As a group, Infant Siblings were delayed in the onset of early developmental milestones and spent significantly less time in a greater number of postures, suggestive of relative postural instability. In addition, they demonstrated attenuated patterns of change in rhythmic arm activity around the time of reduplicated babble onset; and they were highly likely to exhibit delayed language development at 18 months.


Motor development Vocalization Language development Infant siblings