The three-year study found that 64 percent of children initially diagnosed with autism were found to also have apraxia, a rare neurological speech disorder. The study also demonstrates that the commonly used Checklist for Autism Spectrum Disorder can accurately diagnose autism in children with apraxia.
Cheryl Tierney, Penn State associate professor of pediatrics, said:
“Children with apraxia have difficulty coordinating the use of their tongue, lips, mouth, and jaw to accurately produce speech sounds, so that each time they say the same word, it comes out differently, and even their parents have difficulty understanding them.”
Estimates peg in 68 children in the United States as having autism, and one to two in 1,000 having apraxia.
With raised recognition and better evaluation measures, more children are now being diagnosed with autism and apraxia. Developmental experts have long said that autism and apraxia appear to frequently coincide.
30 children between the ages of 15 months and five years were studied by the researchers. Participants were referred to the Penn State Hershey Pediatric Developmental Communication Assessment Clinic for issues involving language, speech, or autism.
After a preliminary diagnostic screening, follow-up testing showed that 63.6 percent of children initially diagnosed with autism also had apraxia and 36.8 percent of children initially diagnosed with apraxia also had autism.
The researchers established that 23.3 percent had both autism and apraxia at the initial diagnosis, and the same amount had neither condition.
With early intervention, outcomes for both autism and apraxia can be improved, so the study highlights the importance of ongoing apraxia assessment for some children with autism, and vice versa.
Tierney now believes that children with autism or apraxia who are non-verbal should be screened for the other condition until they start talking.
Additionally, the new study confirmed that the Checklist for Autism Spectrum Disorder (CASD), a commonly used autism tool, does not over-diagnose autism in children with apraxia.
Penn State College of Medicine psychologist Susan Mayes developed the CASD. It was standardized on children with language disorders (trouble in using language for expression), but not for speech disorders (trouble producing language sounds), so clinicians have questioned if it could accurately be used in children with apraxia.
“We were concerned that children with childhood apraxia of speech were being mislabeled as having autism when they were being evaluated for it, but we found that this was not the case,” Tierney says. “We found that in our diagnostic center, we were not over-diagnosing autism in a cohort of children that had a concern for childhood apraxia of speech.”
Because autism and apraxia have very different interventions, arriving at a correct diagnosis is key for preventing long-term problems, Tierney says:
“CASD is used to diagnose autism, but it can also be used to rule out autism. We wanted to make sure this tool came out negative in a child that just had apraxia and we found that it really does help us distinguish kids accurately. Children who had apraxia without autism, children who had autism but not apraxia, or those who had both or neither were picked up accurately.
The tool was very sensitive in picking up all those different combinations. And that’s good news because we want the right treatment for the right child for the right diagnosis.”
Tierney, Cheryl D.; Gupta, Vidya Bhushan; Angel, Alma Patricia Del; Augustyn, Marilyn Teasing Out Specific Language Impairment From an Autism Spectrum Disorder Journal of Developmental & Behavioral Pediatrics. 33(3):272-274, April 2012
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