Why do some children with autism spectrum disorder (ASD) excel in language development while others don’t?
A new study sheds light on the nuances that lead some children to have strong conversational abilities and others not to speak at all.
Researchers discovered that neural activity in language-sensitive areas of the brain is close to normal for ASD toddlers who go on to develop good language capabilities. It’s nearly absent in ASD youngsters who later have poor language skills.
In typically developing toddlers, the sleeping brain’s response to spoken language predicts later language scores. Typically, the greater the early brain response to language, the better the child’s language level in later years.
In the study, the team found that language-sensitive brain areas are not as active in those toddlers who developed ASD as well as poor language skills. Children in the study with better measured brain activity who were later diagnosed with autism had better language outcomes.
“Our study is important because it's one of the first large-scale studies to identify very early neural precursors that help to differentiate later emerging and clinically relevant heterogeneity in early language development in ASD toddlers,” said Michael Lombardo, a study author from the University of Cyprus, in a statement.
The study was published in the journal Neuron. It was conducted at the University of California, San Diego, Autism Center of Excellence.
Eric Courchesne, co-director of the center, said the findings open new pathways for research
“Why some toddlers with ASD get better and develop good language and others do not has been a mystery that is of the utmost importance to solve,” Courchesne said. “Discovering the early neural bases for these different developmental trajectories now opens new avenues to finding causes and treatments specific to these two very different subtypes of autism.”
Does this mean reading to your sleeping child with ASD could help him or her develop better language skills?
“The findings predict that those toddlers with ASD who have normally active language-sensitive brain areas even at the earliest ages could benefit from lots of language input early on, but we don't know from this study exactly what language input would be best,” Courchesne said.
He added the team wants to conduct more research on the subject.
A Bedtime Story — and a Brain Scan
As part of the study, the researchers looked at 103 infants and toddlers from one to four years old. Of them, 60 had ASD. The other 43 did not, though 19 of them were designated as language/developmentally delayed. The remaining 24 were typically developing children.
The researchers used functional magnetic resonance imaging (fMRI) scans to examine brain activity while the children slept. During the scan, the kids listened to children’s stories read aloud.
The researchers followed up with the children in later years to see how their language skills developed. They found that ASD children who had good language outcomes had shown normal neural activity in language-sensitive brain regions during the study. Those who had poor language outcomes had not had as much activity in those brain areas when they were toddlers.
Next, the researchers tried some behavioral tests and found the same result. They say the scans and behavioral tests combined could help predict language development outcomes. In fact, researchers said they were 80 percent accurate when used together. Used alone, they were 68 percent accurate.
The Benefit of Early Language Tests
Karen Pierce, assistant director of the Autism Center of Excellence, said many parents want to know what lies ahead when their children are diagnosed with ASD. She said using the behavioral and medical assessments could give families an indication of their child’s language development capacity.
“That would be a huge practical benefit for families,” Pierce said in a statement. “In a way, functional activation patterns could serve to signify treatment readiness. If a toddler with autism spectrum disorder is detected with strong brain activation in language areas, then I would predict that this toddler would excel in treatment and have a good long-term outcome.”
“Language deficits are early warning signs of ASD, and eventual language outcome greatly impacts a child’s future,” Courchesne added. “We are taking the first steps toward revealing unique and early neural biological subtypes of ASD that relate to a child’s eventual language ability.”
In the future, the researchers want to look at whether activity in the language centers of the brain can predict responses to treatment.
“Understanding that there are discrete subgroups of early developing ASD … really lays the groundwork for a whole range of really fruitful directions,” Lombardo said.