The secret to reliably diagnosing concussions may lie in the brain’s ability to process sound, according to a new study by researchers from Northwestern University’s Auditory Neuroscience Laboratory.
Concussions, a type of mild traumatic brain injury, are the result of a direct or indirect blow to the head which causes the brain to be jostled within the skull. However, there is little relation between the force of an impact and the potential for injury.
In fact, two athletes can suffer similar hits but experience vastly different outcomes.
Currently, a concussion diagnosis must rely on symptoms alone, as no single test has been developed to reliably and objectively detect them. In this new study, however, the researchers have discovered a biological marker in the auditory system that could take the ambiguity out of diagnosing concussions and tracking recovery.
“This biomarker could take the guesswork out of concussion diagnosis and management,” said lead author Dr. Nina Kraus, the Hugh Knowles Professor in the School of Communication and director of the Auditory Neuroscience Laboratory.
“Our hope is this discovery will enable clinicians, parents, and coaches to better manage athlete health, because playing sports is one of the best things you can do.”
The research involved 40 children being treated for concussion and a control group. The researchers observed participants’ brain activity as they were exposed to auditory stimuli and soon discovered a distinct pattern in the auditory responses of children in the concussion group compared to the control group.
The team placed three simple sensors on children’s heads to measure the frequency following response — the brain’s automatic electric reaction to sound. With this measure they successfully identified 90 percent of children with concussions and 95 percent of children in the control group who did not have concussions.
Participants with concussions had an average of 35 percent smaller neural response to pitch, allowing the scientists to devise a reliable signature neural profile. As the children recovered from their head injuries, their ability to process pitch returned to normal.
“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,” Kraus said.
What was surprising, Kraus said, was the specificity of the findings. “This isn’t a global disruption to sound processing,” she said. “It’s more like turning down a single knob on a mixing board.”
Kraus says that the findings are a major first step toward their ultimate plan of developing a reliable, objective, and user-friendly platform to diagnose concussion.
“With this new biomarker, we are measuring the brain’s default state for processing sound and how that has changed as a result of a head injury,” Kraus said. “This is something patients cannot misreport, you cannot fake it or will your brain to perform better or worse.”
Dr. Cynthia LaBella, the director of the Institute of Sports Medicine at the Ann & Robert H. Lurie Children’s Hospital of Chicago and professor of pediatrics at Northwestern University Feinberg School of Medicine, is Kraus’ partner in the research.
The findings are published in the journal Nature, Scientific Reports.
Source: Northwestern University