The researchers measured EEG patterns in 430 children with autism and 554 control subjects ages 2 to 12. Those with autism had activity patterns that consistently showed reduced connectivity between brain regions, especially in areas associated with language on the left side of the brain.
"The brain works like a series of computers and they have to hook to one another through nerves in the brain in order to connect and function together," says study author Dr. Frank H. Duffy of the department of psychiatry at Boston Children's Hospital. "We can estimate from EEGs how well regions connect to one another. If there is high coherence between different regions of the brain, this indicates the brain is well connected."
The researchers eliminated children with high-functioning autism or Asperger's syndrome, focusing instead on those with "classic" autism symptoms who had been referred for EEG by neurologists, psychiatrists or developmental pediatricians to rule out seizure disorders. "We studied the typical autistic child who is seeing a behavioral specialist. These children are hard to study and it is usually difficult to get EEG recordings from them," says Duffy.
To get an EEG reading, children must wear a cap of electrodes that record electrical signals signifying brain activity. The research team used certain techniques to allow clean readings from the participants, such as letting the children take breaks and adjusting for behaviors like body and eye movement and muscle activity that can throw off recordings.
Image: EEG results, via Shutterstock.