Data for this retrospective study were from the Simon Simplex Collection (SSC), a unique multi-site database project that gathers biological and phenotypic data on children with ASD aged four to eighteen years old without a previous genetic history of ASD. The database establishes a permanent repository of genetic samples from 2,700 families, each of which has one child affected with an ASD and unaffected parents and siblings.
From the SSC, a total of 535 children, ages eight years or older, were studied. Using the Autism Diagnostic Interview-Revised (ADI-R), a standard parent-interview that distinguishes children with ASD from non-ASD populations, and the Autism Diagnosis Observation Schedule (ADOS) , a clinician-administered observation that assesses social, communicative and stereotyped behaviors, researchers selected children because they either had no phrase speech at their time of enrollment in the SSC or their phrase speech onset occurred after age four. Based on ADI-R results and their language presentation, children in this study were administered one of four evaluation modules – no words or single words (Module 1), phrase speech (Module 2) or fluent speech (Module 3 or 4). Of the 535 participants in the study, 119 children mastered phrase speech and 253 children were speaking fluently by their eighth birthday, while 163 children never attained phrase or fluent speech
"We hope the results of this study empower parents of children with autism and severe language delays to know that, with the appropriate therapy, a child will likely make significant gains in this area over time; however, progress should be expected to be slower for those children with lower intellectual abilities," said Dr. Wodka. "Additionally, we hope these findings provide clinicians with better defined therapeutic targets for their patients with autism."
Future longitudinal studies, including both simplex and multiplex families, are required to fully capture the prevalence and predictors of language development in children with ASD. Additionally, further research into the impact of social cognition strategies (e.g., perspective taking) on the development of language, as well as the relationship among specific social deficits and fluent speech development, may hold important implications to the design of intervention.