The brains of children with autism start to differ from typical children as early as 6 months old, a new study found.
The earlier timeframe could lead to therapies for autistic children during critical developmental stages, researchers suggested.
On average, physicians diagnose infants at 18 months for autism, a disorder known for its symptoms of poor social skills, delay in learning to talk and limited interests in activities, according to the Mayo Clinic.
"It's a promising finding," Jason Wolff, lead study author and postdoctoral fellow at the University of North Carolina, told EurekAlert. "At this point, it's a preliminary, albeit great, first step towards thinking about developing a [benchmark] for risk in advance of our current ability to diagnose autism."
Researchers examined 92 at-risk infants who had autistic siblings. Autism affects one in 110 children in the United States, and researchers suspect the disorder has a genetic component since families with an autistic child have a one in five chance of having another, according to the Centers for Disease Control and Prevention.
Researchers studied how different parts of the brains communicate with each other in infants aged 6, 12 and 24 months of age using magnetic resonance imaging (MRI).
Six-month-old children who eventually received an autism diagnosis had denser and more connected communication among sections of the inner "white matter" section of their brains compared to children without autism, researchers found.
The denser and more connected regions of the brain tended to slow down and by 12 months of age, all children had similar communication pathways.
The brain connections became significantly decreased in autistic children by the time they reached 24 months of age, the researchers found.
The American Journal of Psychiatry published the study in its online edition Friday.
The researchers said more work was needed before the observation could be translated into a reliable diagnostic tool, but said early intervention could help those with autism live normal lives.
"We know that early experience shapes and molds the developing brain," Dr. Joseph Piven, psychiatry professor at the University of North Carolina and one of the study's lead authors, wrote in an email.
"So it is feasible to think that [intervention] administered early could alleviate the symptoms and move children closer to the normal trajectories of brain and behavioral development."
Early intervention for autism currently consists of therapy to help children walk, talk and interact with others before an official diagnosis of autism is made. Waiting for an official diagnosis to be made could be too late to begin treatment according to the CDC.
Between 50 and 79 percent of parents whose children underwent early intervention considered it effective, according to a report by the Indiana Resource Center for Autism.
On average, 53 percent of children had functional speech skills before early intervention, whereas 73 percent gained functional speech after intervention, according to a report from the University of Washington.
Autism rates have been increasing steadily since 1996 according to a study published in the Journal of the American Medical Association, but Piven said his study could have great implications for future treatment.
"This study suggests that there is a very important window of opportunity during the early unfolding of the brain and behavioral features of autism," he wrote. "I believe it may have an impact on the field to direct much more attention to this very early presymptomatic time point."
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