Research in Developmental Disabilities and Language Lab

Boys with fragile X syndrome + autism spectrum disorder and autistic boys show high rates of word omission during conversations

Audra Sterling with a study participant performing a task. Photo by Andy Manis
Audra Sterling with a study participant performing a task. Photo by Andy Manis

By Charlene N. Rivera-Bonet, Waisman Science Writer

Note: The lab of Audra Sterling uses identity-first language in response to the majority preference of the autistic community. This story reflects that preference.

Omission of words during conversations may be a unique grammatical marker and part of the language profile associated with autism spectrum disorder (ASD).

A recent study shows that boys with fragile X syndrome and co-occurring ASD (fragile X + ASD), and autistic boys have similar patterns of linguistic errors and omit more words in conversations compared to non-autistic boys. The study, published in the Journal of Speech, Language, and Hearing Research by the lab of Audra Sterling, PhD, associate professor of communication sciences and disorders, sought to identify the differences between grammar error patterns among boys with fragile X + ASD, boys only diagnosed with autism, and a comparison group of non-autistic boys to get a better sense of how autism traits inform language use.

Audra Sterling, PhD
Audra Sterling, PhD. (Photo © Andy Manis)

Fragile X syndrome is the most common form of inherited intellectual and developmental disability in males and commonly co-occurs with ASD. Although it affects both males and females, it is most commonly found and causes more severe symptoms in males. Both individuals with fragile X, and autistic individuals without fragile X present impairments in communicating thoughts and feelings – known as expressive language. Given the high occurrence of ASD in fragile X, studying both conditions could reveal language patterns unique to ASD that may inform potential language interventions.

Having strong spoken language skills provides an important foundation for children’s academic, cognitive, and socioemotional development. Language impairments in kids with neurodevelopmental disabilities may have negative effects in different life outcomes, which makes it critical to understand the root of their language difficulties in order to develop targeted treatments.

During the study, the researchers had conversations with the boys using prompts related to their interests and hobbies, sports, pets, school, families, and vacation. “We know that conversations are fairly demanding for these boys, so we were curious about how they might express themselves and how these linguistic structures that they have might be represented in conversation where there are extra social demands,” says Nell Maltman, PhD, assistant scientist and first author of the study.

Using the conversations, Maltman and her colleagues measured three types of linguistic errors: omission of words, word level errors, such as using an incorrect word, and utterance level errors, such as using an incorrect sentence structure.

When they compared the patterns of errors between boys with fragile X + ASD and autistic boys – both groups matched for autism traits – they found that both had similar rates of errors across all domains, and produced a greater proportion of omission errors relative to other error types.

A deeper dive into the conversations revealed that the words most commonly dropped by the boys were pronouns and verbs, which are key parts of a sentence. “[Pronouns and verbs] could have pretty significant effects on the understanding of a message if you’re the listener speaking with someone who’s dropping words like that, because they’re so central to a shared message,” Maltman says.

Nell Maltman, PhD
Nell Maltman, PhD

The next question they asked was whether the error rates were greater or equal to non-autistic boys that were matched in language skills and mental age. Boys with fragile X + ASD and autistic boys made omission errors at a significantly higher rate than the language and mental age-matched non-autistic boys. “What we take away from this is that omissions could potentially be a grammatical marker associated with autism-related traits. That’s something that we want to think about as it pertains to clinical interventions,” Maltman says.

Omitting words in conversations may lead to misunderstandings and have implications for interpersonal interactions.  The authors will continue to explore the possibility of whether targeting omissions and trying to facilitate the use of full sentence structures helps boys with fragile X + ASD and autistic boys with conversations and social language in an intervention context.

The researchers are now looking to understand how these omission errors affect overall social communication and to identify potential links between challenges with structural language and social language.

Most of the research on fragile X syndrome is done in boys because of the higher prevalence. However, girls are affected too. Sterling and Maltman plan to include girls in future studies of FXS and language to understand how an additional X chromosome impacts language characteristics.

This work was supported by the National Institutes on Deafness and Other Communication Disorders (R01 DC019092; R03 DC011616; 1K23DC016639-01; T32DC005359), the Eunice Kennedy Shriver National Institute of Child Health & Human Development Grants (T32HD007489; U54 HD090256), and the University of Wisconsin-Madison.