Right when an infant or toddler begins to show the first signs of potential autism, neural activity in their language-sensitive brain regions may predict whether they will develop good or poor language skills, according to new findings published in the journal Neuron.

Autism spectrum disorder (ASD) can result in strikingly different clinical outcomes, with some children having strong conversation abilities and others having no language skills at all.

“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,” says senior author Eric Courchesne, co-director of the University of California San Diego (UCSD) Autism Center, where the study was designed and conducted.

“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.”

The study involved 60 ASD and 43 non-ASD infants and toddlers who were followed until early childhood. The researchers used the natural sleep functional magnetic resonance imaging (fMRI) method developed by the UCSD Autism Center investigators to record brain activity in the participants as they listened to excerpts from children’s stories.

ASD children who ended up having strong language skills showed normal patterns of neural activity in language-sensitive brain regions, including superior temporal cortex, during infant and toddler ages. On the other hand, ASD children with poor language outcomes showed very little activity in superior temporal cortex when they were toddlers or infants.

“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,” says first author Michael Lombardo of the University of Cyprus.

“Understanding that there are discrete subgroups of early developing ASD that are distinguished by developmental behavioral trajectories, neural underpinnings, and brain-behavioral relationships, really lays the groundwork for a whole range of really fruitful directions,” Lombardo says.

The findings also showed that, when combined with behavioral tests, these striking early neural differences may help predict later language outcome by early childhood. The accuracy of the combined neural and behavioral measures was 80%, compared with 68 percent for each measure alone.

“One of the first things parents of a toddler with ASD want to know is what lies ahead for their child,” says co-author Karen Pierce, also co-director of the UC San Diego Autism Center.

“These findings open insight into the first steps that lead to different clinical and treatment outcomes, and in the future, one can imagine clinical evaluation and treatment planning incorporating multiple accurate behavioral and medical prognostic assessments. That would be a huge practical benefit for families.”

Source: Cell Press