A readily available brain test could someday be used to diagnose autism in children as young as 2 years old, offering the potential for earlier intervention, according to a new study published online in the journal BMC Medicine.
Researchers at Boston Children's Hospital used electroencephalograms (EEGs), tests that measure electrical activity in the brain, to compare the brains of 430 children with autism and 554 normal children between the ages of 2 and 12.
Children with autism showed reduced connectivity among a number of areas of the brain, and these patterns were different than the patterns observed in normal children.
"Most of these patterns provide enough information to cleanly separate 2 to 12-year-old autistic children from neurotypical controls," said Dr. Frank Duffy, a study co-author and director of developmental neurophysiology at Boston Children's Hospital.
Part of what sets this research apart from other studies, Duffy explained, is that the subjects were children with classic signs of autism, including communication difficulties, compulsivity, impulsivity and problems engaging other people. As a result of these symptoms, research can be very challenging.
"The problem with studying autistic children is that they aren't very cooperative," Duffy said. "Many of the studies have taken extreme cases, such as high-functioning autistics, adults with autism or people with Asperger's syndrome." Asperger's syndrome is a milder form of autism marked by language and communication difficulties.
While not yet ready for real-world diagnosis, Duffy said it's possible EEGs, which are easy to get and relatively inexpensive, could eventually be used to diagnose autism at younger ages.
Autism Speaks, a national non-profit organization dedicated to raising awareness about autism, said the study helps explain the difficulties faced by people with autism.
"This reduced functional connectivity in the brain helps us understand the impairments associated with autism," Geraldine Dawson, chief science officer at Autism Speaks, said in an email. "The hope is that early behavioral intervention can help mitigate these functional impairments helping to form the connections that naturally develop in typical children."
But Dr. Max Wiznitzer, a child neurologist at Rainbow Babies & Children's Hospital said the value of EEGs lies in areas other than making a diagnosis.
"This is more of a confirmatory tool," he said. "An autism diagnosis is primarily clinical," he added, meaning a specialist makes the diagnosis.
He also said EEGs can be used to determine whether an intervention is working.
"I think the value is in the research and for monitoring how people are responding to treatments."
Wiznitzer also said that some of the connectivity patterns observed in the study could also be signs of other types of disorders. One of the patterns, for example, involved the left of side of the brain in an area where high-level language takes place.
"This may also be found in kids with developmental language disorders," he said.
Duffy said he does plan to repeat the study in children with other types of autism to determine whether the same patterns exist.