47 Prevalence of and Factors Associated with Language Impairment in Canadian Children with ASD

Abstract

Abstract Background Autism Spectrum Disorder (ASD) is a life-long neurodevelopmental disorder affecting 1 in 66 Canadians aged 5-17, and language impairment is a common comorbidity in this population. We aimed to determine the relative prevalence of diagnosed language impairment in children with ASD. We also examined factors associated with language impairment in children with ASD. Objectives 1 – To determine the relative prevalence of language impairment in children diagnosed with ASD. 2 – To identify factors associated with language impairment in children with ASD. Design/Methods Our study sample included 6,862 children aged 0-19 years, assessed for ASD (61% diagnosed with ASD) between 2010-2017 in British Columbia, Canada. ASD was diagnosed by a provincially qualified specialist and the assessment included the use of the Autism Diagnostic Observation Schedule (ADOS-2) and Autism Diagnostic Interview-Revised (ADI-R). We also looked for associations between language impairment and gender, age, intellectual disability (ID), family history of language disorders, and attention deficit hyperactivity disorder (ADHD), using chi-square analyses. Results The overall prevalence of language impairment in children diagnosed with ASD (n = 1820, 44%) was similar to those not diagnosed (n = 1199, 44%). There was more mixed receptive/expressive (80% vs 65%) and less expressive only (22% vs 29%) language impairment in children diagnosed with ASD than without. Looking only at the children diagnosed with ASD, there was no significant difference when evaluating gender (boys 44%, girls 41%; p = 0.094), but younger age was positively associated with language impairment (age <6y 53%, ≥6y 24%; p < 0.01). Increasing severity of ID was negatively associated with language impairment (mild: 44%, p = 0.911; moderate: 33%, p = 0.001; severe: 21%, p < 0.001). Family history of speech language disorder was positively associated with language impairment (no family history 12%, family history 20%; p < 0.01). Presence of comorbid ADHD was negatively associated with language impairment (no ADHD 47%, ADHD 28%; p < 0.01). Conclusion In children who have been referred for an ASD assessment, the prevalence of language impairment is similar in those with and without ASD. Children with ASD are more likely to be diagnosed with mixed language impairment than expressive only language impairment, although this difference may in part be due to challenges in fully assessing a child with ASD’s receptive language.