The 'canary in the mine’ for subconcussive head injury

It is widely accepted that undiagnosed concussions are dangerous to the health and safety of the athlete. To prevent long-term concussion damage, sports organizations focus on detecting concussion symptoms, providing the athlete with care once an injury is suspected.

Yet even small victories have shown to adversely affect the brain over time.

Player-to-player or player-to-ground contact in football, elbows to the head in basketball, or tackling the ball in soccer cause subconcussions, injuries to the brain not sufficient to cause severe symptoms of a detectable concussion.

Some athletes’ brains don’t change from these repeated hits, but for others, subconcussions have been shown to cause chronic traumatic encephalopathy (CTE), a progressive degeneration of the brain that leads to mood instability and problems with memory, attention and thinking.

A study and publication in the Journal resulted from a joint collaboration between the Northwestern Auditory Neuroscience Laboratory and Northwestern University Athletics and Recreation. Exercise, sports and movement One day he discovers a brain measure that will help identify an athlete’s tipping point.

„There’s no way to know when an athlete will reach their tipping point—when CDE becomes the inevitable result of repeated concussions and that collateral impact,” said Nina Krause, professor of neurobiology and otolaryngology in the Hugh Knowles School of Communication. Northwestern, who served as senior author on the study.

„By finding the proverbial 'canary in the coal mine’, we can increase player safety without compromising the games we love,” said Krause. „Identifying what is 'too much’ for an individual player can prevent the need to make major changes to the game.”

A biological measurement called frequency-following response (FFR) is obtained by placing a few sensors on the athlete’s head and playing sounds in their ears. FFR is objective and easy to obtain.

Unlike current concussion tests, which assess balance, vision and cognition, the FFR examines auditory processing. The authors found that the brain’s response to pitch — the part of sound that differentiates notes from a piano or different voices — was poorer in contact athletes compared to non-contact athletes. Auditory processing may be more sensitive than other domains currently involved in concussion assessment.

This finding was specific to male contact athletes, for whom more years playing contact sports led to poorer pitch execution, the study reported.

Pitch is processed in multiple areas of the brain, and the pickup of sensors reflects coordinated neural activity within and across these multiple areas. Impaired pitch processing in contact athletes suggests reduced coherence in the firing patterns of these neurons as a result of repeated subconcussions.

„Why women’s brains don’t show a greater impact on pitch processing from playing contact sports needs further study,” Krause said. „Estrogen mediates the relationship between concussion and brain dysfunction.”

Krause is an expert on auditory processing, and his holistic view of hearing and how it can inform us about brain health is explored in his book „Sound Mind.”

„Overall, the study suggests that acoustic processing may be a useful way for scientists and sports medicine practitioners to assess and understand how concussions affect brain health,” he said.

Being physically active is one of the best things we can do for our overall health, including our brain health, Krause said. However, this research will ultimately help people make more informed decisions about which sports they like to play and what the effects of different activities are over different periods of time.

The study involved more than 700 male and female athletes who played 19 contact and non-contact sports ranging from swimming, cross country and golf (non-contact) to soccer, lacrosse and field hockey (contact).