Electrical Activity in the Brain Can Distinguish Children With Autism
Tests that measure the electrical activity in the brain can distinguish children with autism from children with typical brains as early as age 2, researchers at Boston Children's Hospital have found.
Researchers compared raw data from the electroencephalogram tests, or EEGs, of 430 children with autism and 554 other children ages 2 to 12. They found that children with autism had consistent EEG patterns showing altered connectivity between different parts of the brain—generally, they showed reduced connectivity compared with the other children's brains. Their study was published this week in the online journal BMC Medicine.
This altered connectivity stood out in the left side of the brain, which controls language. Researchers focused on children with autism who had been referred for EEGs by neurologists, psychiatrists, or developmental pediatricians to rule out seizure disorders. Children diagnosed with seizure disorders, those with Asperger syndrome and other high-functioning children with autism were excluded from the study.
"We studied the typical autistic child seeing a behavioral specialist—children who typically don't cooperate well with EEGs and are very hard to study," Dr. Frank H. Duffy, of the department of neurology, said in a statement. "No one has extensively studied large samples of these children with EEGs, in part because of the difficulty of getting reliable EEG recordings from them."
He and Heidelise Als of the hospital's department of psychiatry used techniques to get clean, EEG recordings from children with autism while they were awake, such as allowing them to take breaks. They used computer algorithms to adjust for the children's body and eye movements and muscle activity, which can throw off EEG readings.
The pair compared EEG readings from multiple electrodes placed on children's scalps, and quantified how synchronized any two given EEG signals were—something the researchers call the degree of coherence. If two or more waves rise and fall together over time, that shows those regions of the brain are highly connected.
Duffy compared this to two people singing "Mary Had a Little Lamb" together—if they can see and hear each other, they are more likely to synchronize their singing, so their coherence is high.
There are other ways to identify whether children have any type of autism, but many of these signs go unnoticed. Early detection, however, can have a huge effect how students progress and develop if they get early-intervention services to match their needs.
In addition, the National Association of School Psychologists reports that most often, students with autism are diagnosed by school staff or a combination of school staff and others. Could these EEG tests change all that?
The researchers think so. They believe their findings could lead to a diagnostic test for autism, particularly at younger ages when behavior-based measures are less reliable. Their next step is to repeat their study in children with Asperger syndrome to see how their EEG patterns compare with children with autism. They also plan to study children whose autism is associated with other conditions such as Fragile X syndrome and extremely premature birth.