Brain scans of babies may predict which ones will develop autism, a debilitating disorder whose symptoms can be softened with early behavioural therapy, researchers have found.
In a trial, MRI scans revealed which infant brains were growing at a faster-than-normal rate -- a telltale sign of autism spectrum disorder (ASD), they wrote in the science journal Nature.
It was already known that children with ASD have larger brains than unaffected ones, but not at which age the difference kicks in.
Autism can be diagnosed from about two years of age, when behavioural and communication problems start becoming evident.
ASD is a group of brain development disorders that includes conditions such as autism and Asperger syndrome, all characterised by difficulties with social interaction and communication.
Sufferers often display repetitive behaviour, while some excel at non-verbal skills such as mathematics.
According to the World Health Organization, about one child in 160 has ASD -- possibly much more.
There is no cure.
The latest study was carried out in 106 infants at high risk of ASD, which runs in families, and 42 low-risk peers.
It found faster growth of the cortical surface at six and 12 months of age of infants who were later diagnosed with ASD at 24 months, compared to non-affected children.
Based on their findings, the team developed a computer algorithm to predict, with an accuracy of about 80 percent, which infants will develop ASD.
Fifteen children in the trial had a positive diagnosis at 24 months.
"Our study shows that early brain development biomarkers could be very useful in identifying babies at the highest risk for autism before behavioural symptoms emerge," said the study's senior author Joseph Piven of the University of North Carolina.
Such a test may be useful to intervene "pre-symptomatically", at an age when the human brain is most malleable, a university statement said.
"Such interventions may have a greater chance of improving outcomes than treatments started after diagnosis."
Further research is needed before MRIs can be used as a clinical tool for early detection, the researchers cautioned.
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