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Autism likely has deep genetic roots, but the latest research provides hope that some learning techniques can lessen symptoms of the developmental disorder.

In children with the mildest cases of autism, these techniques resulted in changes in their brains that made them “indistinguishable” from those of unaffected children of the same age — essentially normalizing them, according to Geraldine Dawson in the department of psychiatry at the University of North Carolina at Chapel Hill.

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The results, published in the Journal of the American Academy of Child & Adolescent Psychiatry, are validation for the Early Start Denver Model (ESDM), a behavioral-intervention program that involves intensive engagement with children diagnosed with autism spectrum disorders (ASD). Specially trained counselors work with children twice a day in two-hour sessions, five days a week. In 2009, Dawson’s group reported on related work that showed that children with autism who received this intervention beginning at 18 months for about two years showed an average improvement in IQ scores of 17.6 points and dramatic gains in adapting so-called normal developmental behaviors, such as brushing their teeth and engaging with family members during meals.

Dawson and her colleagues were curious about what was driving the change. Could alterations in the brains of the Denver Model toddlers be responsible? After all, in the first six years of life, the brain is remarkably plastic, meaning it can be molded and shaped depending on the growing child’s experiences and exposures. To find out, she enrolled a group of 48 toddlers ages 18 months to nearly 3 years who had been diagnosed with ASD. Half were randomly assigned to receive the Denver intervention, while the other half were assigned to traditional community-intervention programs that included some special-education programs at schools. After about two years, Dawson’s group took electroencephalography (EEG) readings of the electrical activity of all the children ‘s brains while they were looking at pictures of human faces or toys, and compared these readings with those of similarly aged children without autism. In most of the affected children, previous studies showed the brain is more highly activated when the child looks at an inanimate object like a toy, and less activated when looking at a human face. In the current study, however, the children participating in the Denver program showed the opposite effect: their brains lit up more when looking at a woman’s face than when viewing a toy.

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“We essentially reversed the pattern so kids with autism are now showing greater normal brain activity when they saw a woman’s face and less activity when looking at objects,” says Dawson. “In fact, the brain-activity patterns of kids with autism who received ESDM were no different than a typical 4-year-old’s [pattern] when viewing a woman’s face. They were indistinguishable.”

Dawson says the intervention is not a cure, but that the brain changes hint that some early drivers of ASD may be manipulated and even redirected toward more normal development. The findings may also reveal where in the brain and which systems are responsible for the problems associated with autism. “By providing intervention early on, we can mitigate the severity of autism symptoms and perhaps really alter the trajectory of the disease at both the level of behavior and the brain,” she says.

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That’s what has the autism-research community excited. If it’s possible to change the course of the disease, and possibly reduce the severity of symptoms, it could mean the difference between a child who isn’t able to communicate and engage with family or friends and one who may be able to participate in a normal classroom.

The key, however, is the ESDM program, and those who provide the therapy need to be certified by a program Dawson and her co-developer, Sally Rogers, have created at University of California, Davis. About 1,000 people have been trained in the technique so far, with 15 specifically trained to teach the model to others. So far, ESDM is available in the U.S., Australia, Japan, India and Sweden, and while the researchers are hoping to expand the program, they are wary about losing the intimate and specialized techniques required to conduct the behavior interventions properly. While most of the sessions look like play, they are carefully designed to engage and reinforce children’s social skills by asking them about how characters in a book might be feeling, for example, or by helping children to read the body-language cues that most of them miss.

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And given the latest understanding of how plastic the brain remains, even after childhood, Dawson says the results are encouraging for not just newly diagnosed toddlers with autism but those who have been living with the disorder for years. “Although it’s optimal to start as early as possible,” she says, “I don’t believe there is any point where the door is shut and the intervention is not helpful.”