The way a child with autism communicates through speech plays a significant role in educational, psychosocial and eventual vocational aspects of quality of life. Some children with autism, both with and without language impairment, have challenges acquiring articulate speech and mastering the prosodic features expected when speaking in different situations.
Lawrence Shriberg and his colleagues at the University of Wisconsin-Madison studied speech and prosody features of individuals with autism using both perceptual and acoustic measures. In collaboration with Raphael Bernier and his research group at the University of Washington in Seattle, Shriberg is completing a study involving 111 children and adults from the Simons Variation in Individuals Project (Simons VIP), who each have a deletion or duplication at chromosomal region 16p11.2.
Previous studies estimate that between 20 and 24 percent of individuals with a copy number variant (CNV) at 16p11.2 have co-occurring autism. Additionally, the complex phenotype of 16p11.2 deletion/duplication syndrome has been found to include speech sound disorders, notably a rare motor speech disorder called childhood apraxia of speech (CAS). Shriberg and his group sought to determine if people with both 16p11.2 deletion/duplication syndrome and autism have more frequent and possibly different types of speech sound disorders — particularly CAS — compared with individuals who have 16p11.2 CNVs but not co-occurring autism.
Their findings indicate that speech disorders, including CAS, are more frequent in individuals with 16p11.2 CNVs than in population samples. This confirms prior findings indicating that disruptions in this area may directly or indirectly underlie cognitive and neuromotor pathways to speech disorders. Their results also suggest that autism co-occurring with 16p11.2 disruptions does not confer increased risk for different types of speech disorders, including CAS.
The researchers found that 16p11.2 deletions are approximately three times more likely than duplications to be associated with speech and motor speech disorders, replicating findings in the broader Simons VIP sample of the association of 16p11.2 deletions and duplications with other verbal traits.
Shriberg and Bernier plan to examine the neuroimaging data and other neurological data available in the Simons VIP database for the participants identified with speech disorders (especially motor speech disorders) in this sample, including participants with inappropriate prosody. Speech and prosodic aspects of communication are topics of central interest in explaining the origins and lifespan expression of autism.