More non-verbal children with autism spectrum disorder (ASD) start to speak by the age of eight than previously thought, say researchers at the Kennedy Krieger’s Center for Autism and Related Disorders. A new study announced on March 4, 2013, reveals that 70 percent of autistic children with a history of severe language delay will be able to speak in phrases or speak fluently by time they are eight years old.
Autistic children with a severe delay in speech development achieve more language skills by the age of four than researchers previously believed. Limited research has been done on the language delays and the abnormalities in communication that characterize autism.
Researchers examined children who were not able to express themselves in meaningful phrases by the age of four to determine the relationship between language delay and the symptoms of autism. The study defined phrase speech as spontaneous three-word phrases that do not mimic other people's speech, and fluent speech as the ability to speak complex sentences about topics outside of their environment.
“We found that nonverbal intelligence was the strongest predictor of phrase speech, while social interest and engagement were as robust, if not greater, when predicting the age that children attained phrase speech and fluent speech,” said Ericka L. Wodka, Ph.D., a neuropsychologist in Kennedy Krieger’s Center for Autism and Related Disorders and lead study author. “Children with typical non-verbal intelligence attained language almost six months ahead of those with scores below the average.”
Researchers say that the findings reinforce the conclusion that factors such as social engagement and non-verbal intelligence have a great influence on symptoms of ASD such as abnormal sensory and repetitive behaviors. “Our findings continue to support the importance of considering both non-verbal intellectual level and social communication in treatment planning, highlighting the differing impact of these factors as related to treatment goals,” said Dr. Wodka.
The Simon Simplex Collection (SSC), a multi-site database, provides biological information and data on the characteristics of children with ASD who are between the ages of 4 to 18 years of age, do not have a genetic history of autism, and whose parents or siblings do not have ASD. The database contains genetic samples from 2,700 families who have an autistic children who have siblings and parents who are not affected by ASD.
Researchers studed 535 children aged 8 and older. Researchers used a standard parent interview and a clinician-administered Autism Diagnosis Observation Schedule to assess communicate and social behaviors of children with autism.
The study found that:
- 119 children mastered phrase speech
- 253 children spoke fluently by their eighth birthday
- 163 children never achieved fluent or phrase speech
“We hope the results of this study empower parents of children with autism and severe language delays to know that with the appropriate therapy, a child will likely make significant gains in this area over time; however, progress should be expected to be slower for those children with lower intellectual abilities,” said Dr. Wodka. “Additionally, we hope these findings provide clinicians with better defined therapeutic targets for their patients with autism.”
Researchers say more longitudinal studies are needed on possible predictors of language and speech development.