If an athlete receives a concussion, there's no question that they should receive medical attention as soon as possible. What can be harder to tell, however, is whether or not they've actually got a concussion. In the recent past, we've seen systems that track eye movements in order to determine if a traumatic brain injury has occurred. Now, scientists from Illinois' Northwestern University are suggesting that the way in which the brain processes sound may be an even better indicator.

Led by Prof. Nina Kraus, a research team studied a group of 40 children being treated for concussion, along with an uninjured control group. Each child had three sensors placed on their head, to measure their "frequency following response" as they were exposed to auditory stimuli – frequency following response is described as "the brain's automatic electric reaction to sound."

It was found that the children with concussions had on average a 35 percent smaller neural response to pitch (that figure returned to normal as they recovered). Using that profile, the scientists were able to correctly categorize 90 percent of the injured children, and 95 percent of those in the control group.

"Making sense of sound requires the brain to perform some of the most computationally complex jobs it is capable of, which is why it is not surprising that a blow to the head would disrupt this delicate machinery," says Kraus. She is now hoping to develop a portable device that could be used by coaches or other people on the sidelines or in clinics, to immediately determine if a player has been concussed.

Scientists in Florida, meanwhile, have additionally developed a blood test that can be used to diagnose concussions.