Pragmatic Language Markers of Autism Diagnosis and Severity.

Purpose: Assessment of pragmatic language difficulties is limited with conventional tests but can be performed with informant reports. We evaluated the performance of a parent-completed language scale in differentiating autism from typical development (TD) and another neurodevelopmental disorder. Specifically, we aimed to gauge the respective values of structural and pragmatic language scores for diagnostic discrimination and for predicting severity of social impairment in autistic children. Method: 174 children aged 7 to 17 (101 with autism, 45 with ADHD, 28 with TD) were evaluated with the ADOS-2 and an abbreviated version of the WISC. Parents completed the Children's Communication Checklist, 2nd Edition (CCC-2) and the Social Responsiveness Scale. CCC-2 mean differences across diagnostic groups were tested with analysis of variance and covariance. Multiple linear regression was used to compare the structural and pragmatic CCC-2 scores in predicting autism symptom severity. Results: Both structural and pragmatic language scores discriminated between the three diagnostic groups, with stronger effects for the pragmatic scores. Pragmatic scores remained robust predictors of ADHD and ASD diagnoses even after accounting for cognitive and structural linguistic differences. Among autistic children, social impairment severity was associated with pragmatic, but not structural, language profiles. Conclusions: In order to characterize pragmatic language, easy to administer parent questionnaires such as the CCC-2 may support clinicians who are considering an autism diagnosis and needing to evaluate and monitor social communication.