Vocalization Behavior During the Autism Observation Scale for Infants in Siblings of Children with Autism Spectrum Disorders

Abstract

Due to the high heritability rate of autism, recent investigative efforts have focused on prospectively studying infant siblings of children with autism spectrum disorders (ASD) in order to map the developmental trajectory and potentially lower the age at which children may be diagnosed. Additionally, children with ASD typically exhibit language delays, therefore the purpose of this study was to evaluate pre-speech vocal productions of 6-month old infant siblings at high-risk (HR) and low-risk (LR) for ASD. Video recordings collected during standardized testing were analyzed and coded for babbling, consonant inventories, and atypical vocalizations. These data were then evaluated to determine if vocal behavior at 6 months was predictive of an autism diagnosis at 24 months. At 6 months, HR infants produced a higher percentage of canonical syllables than their LR peers. No other significant differences were found, and vocal behaviors at 6 months were not associated with higher scores on the Autism Diagnostic Observation Schedule (ADOS) at 24 months. Therefore, the results of this study provide evidence that there are few meaningful differences in vocal behavior between HR and LR infants at 6 months.