As families and therapists know well, some children with autism make rapid progress, while others develop social and verbal skills very slowly. Even among those slow to speak, many eventually become highly verbal. Others continue to communicate with only a few if any words.
Autism researchers have long sought to identify the brain patterns that underlie such differences – for good reason. Such understanding could guide the personalization of therapies that address the root causes of an individual’s social and communication disabilities. It might also enable earlier detection and treatment of autism.
A study published today in PLOS ONE is among the first to identify such a predictive brain pattern in toddlers.
The lead author is speech scientist Patricia Kuhl, Ph.D., of the University of Washington, Seattle. Her co-authors include Autism Speaks Chief Science Officer Geri Dawson, Ph.D. Dr. Dawson is also a research professor at the University of North Carolina, Chapel Hill.
Responding to Familiar vs. Unfamiliar Words
In the study, 2-year-olds (24 with autism and 20 without) listened to a mix of familiar and unfamiliar words. Researchers monitored their brain responses using an elastic cap with sensors. The sensors measured a type of brain activity called event-related potentials.
The typically developing toddlers (those not affected by autism) showed clear differences in which part of their brains responded to known versus unknown words. Their brains responded more strongly to familiar words in a language area on the brain’s left side. This was likewise true of one subgroup of the children with autism.
By contrast, another subgroup of children with autism showed little difference in how their brains responded to familiar versus unfamiliar words. In either case, their response came from a broad area on the brain’s right side. This pattern is not seen in typically developing children of any age.
Implications for Improving and Personalizing Therapy
The researchers also found that, among the children with autism, those with the more-typical brain response to familiar words had less-severe problems with social interactions.
This suggests that the brains of children with less severe symptoms can process words in ways similar to those of children without autism – even before they learn to speak, Dr. Kuhl says. It also supports earlier research showing that early autism therapy focused on improving social interaction also helps promote verbal skills. "Social learning is what most humans are about," Dr. Kuhl explains. "If your brain can learn from other people in a social context you have the capability to learn just about anything."
These insights have potential for guiding personalized therapy, Dr. Dawson adds. “Recent studies have shown that nonverbal children can be helped to develop spoken language if they are given speech-generating devices such as an iPad,” she explains. “But, we haven’t known how to identify which children are likely to benefit from such help. This measure may help us to do so early on – so that these children can have the best possible long-term outcomes.”
Such noninvasive brain monitoring might also be used to measure a child’s response to treatment, the researchers say. More typical brain activity may signal that a child's brain is reorganizing to process words, they explain. “We believe this reorganization depends on the child's ability to learn from social experiences," Dr. Kuhl adds.
Predicting Future Development
The researchers also followed the children’s development for four years after the brain-activity monitoring. Their outcomes varied widely. However, those with the more typical brain patterns at age 2 made significantly greater progress in all areas of function – social, language and cognitive (IQ) – by age 6.
Eventually, such brain pattern differences might be used to flag infants and toddlers at risk for autism before outward symptoms appear, the investigators say. But more research is needed to confirm the findings, they add.