New findings published in Pediatrics (Epub ahead of print) by the Kennedy Krieger Institute's Center for Autism and Related Disorders reveal that 70 percent of children with autism spectrum disorders (ASD) who have a history of severe language delay, achieved phrase or fluent speech by age eight. This suggests that more children presenting with ASD and severe language delay at age four can be expected to make notable language gains than was previously thought. Abnormalities in communication and language are a defining feature of ASD, yet prior research into the factors predicting the age and quality of speech attainment has been limited.
The study used the largest sample to date to examine the relationship between key deficits associated with ASD and attainment of phrase and/or fluent speech following a severe language delay, characterized by a child not putting words together into meaningful phrases by age four. As a common milestone of speech development, phrase speech is defined as using non-echoed three-word utterances that sometimes involve a verb and are spontaneous meaningful word combinations; whereas fluent speech is defined as the ability to use complex utterances to talk about topics outside of the immediate physical context.
"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 nonverbal intelligence attained language almost six months ahead of those with scores below the average."
These findings reinforce that core abilities, such as nonverbal intelligence and social engagement, have a greater influence on the development of communication than other behaviors associated with ASD, such as repetitive and abnormal sensory behaviors. "Our findings continue to support the importance of considering both nonverbal intellectual level and social communication in treatment planning, highlighting the differing impact of these factors as related to treatment goals," said Dr. Wodka.
Data for this retrospective study were from the Simon Simplex Collection (SSC), a unique multi-site database project that gathers biological and phenotypic data on children with ASD aged four to eighteen years old without a previous genetic history of ASD. The database establishes a permanent repository of genetic samples from 2,700 families, each of which has one child affected with an ASD and unaffected parents and siblings.