Autism research has proven to be a tricky field.
The findings also jibe with work in the past decade suggesting that brain overgrowth in infancy occurs in a subset of children with the condition.
The team scanned the brains of all three groups three times - at 6, 12 and 24 months of age. "Early diagnosis in autism does make a difference".
Next, the team developed an algorithm that predicted, based on all the brain measurements, about 80% of the 15 high-risk infants who would later meet the criteria for autism at 24 months. The new findings hold particular promise for families of children who are at high-risk for the disorder, and may have practical implications for them "in the not too distant future", Piven argued.
Doctors say they've found changes in the brains of infants, who later go on to develop autism.
Autism spectrum disorders-so called because they present a wide range, or spectrum, of different social and communication challenges-are often characterized by behaviors that include rocking motions or obsessions.
There's more on autism screening at U.S. Centers for Disease Control and Prevention.
They found that the babies who developed autism experienced a hyper-expansion of brain surface area from six to 12 months, as compared to babies who had an older sibling with autism but did not themselves show evidence of the condition at 24 months of age. Now about 3 million people of all ages live with autism in the U.S. For the study, researchers conducted MRI scans of the babies at six, 12, and 24 months of age. Increased surface area growth rate in the first year of life was linked to increased growth rate of brain volume in the second year of life. The researchers note that the greater the brain overgrowth, the more severe a child's autistic symptoms tended to be.
Numerous measurements the algorithm relied on most are related to surface area, and came from 6-month-old children. And the team was pleased with the prediction accuracy.
But the new findings ― although preliminary ― could represent a major breakthrough in terms of doctors' ability to predict a child's autism risk at much younger ages, even before symptoms appear. But Elison added it will be a long time before the research is ready for clinical use.
"We're looking at this as an option for high-risk children", Elison said.
'This means we potentially can identify infants who will later develop autism, before the symptoms of autism begin to consolidate into a diagnosis, ' Piven said.
He added: 'We haven't had a way to detect the biomarkers of autism before the condition sets in and symptoms develop. Usually, babies that have otherwise progressed normally will start showing subtle changes in behavior: difficulty focusing or speaking with others, or trouble pointing at objects. "In Parkinson's, for instance, we know that once a person is diagnosed, they've already lost a substantial portion of the dopamine receptors in their brain, making treatment less effective".
Kerry Keller's oldest son was diagnosed with autism at the age of two.
"Right now, we're at the point where generally, the age of diagnosis is 4, there's indications that say we should be able to diagnose kids at age 2, and now this is saying it could be even earlier than that", Pletcher said.
"We view this is, particularly in this high-familial risk sample, as a very real possibility of pre-symptomatic detection", Piven said.
The National Institutes of Health (grants HD055741, EB005149, HD003110 and MH093510) funded this study.
"This is a first step towards something that has tremendous potential for early identification and intervention", says lead investigator Joseph Piven, Thomas E. Castelloe Distinguished Professor of Psychiatry at the University of North Carolina at Chapel Hill. Other key collaborators are McGill University, the University of Alberta, the College of Charleston, and New York University. Yet, for infants who have an autistic sibling, the risk of developing the disorder may be as high as one in five.
About Children's Hospital of Philadelphia: Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Its pediatric research program is among the largest in the country.