"Each is promising, but like all things in science, the devil is in the details," Patterson said. "The history of science is littered with initial findings that don't hold up, or are less exciting with further study."
In fact, while the findings of this latest study seem to add to growing evidence that brain wave patterns may be a predictive marker for the disorder, researchers did not follow the infants to see if they went on to actually develop autism.
And until studies find a potential parallel between brain wave patterns and a subsequent diagnosis of autism, many experts are not convinced EEGs are able to lead experts to diagnose autism any earlier.
"The test tells us no more clinically than knowing that a child has a sibling with autism," said Catherine Lord, director of the University of Michigan autism and communication disorder center.
Still, Lord said it is interesting to see that there are slight neurological differences in children whose siblings are on the spectrum. Previous studies suggest that children whose older siblings have an autism spectrum disorder have up to a 10 percent chance of developing autism.
This study, she said, is one of many that suggests brain activity is different among those who have a family history of autism. But it's hard to tell what the difference means, if anything, for a child's chances of developing autism, she said.
"We have to be careful to take ... studies such as these for what they are, basic research with potentially very important implications, not clinical findings," Lord said.