Reducing concussion risk requires some sort of cushioning inside the skull.
The National Football League’s playoffs have begun. During the regular season, the conversation among doctors, players, league officials, politicians and parents about traumatic brain injuries in sports seemed to gain in volume and intensity. New revelations from retired NFL players who announced that they had the progressive neurodegenerative brain disease chronic traumatic encephalopathy, or CTE, helped fuel these discussions.
The key to beating the concussion crisis lies in dealing with what’s happening inside the skull, not outside of it. Because the brain doesn’t fill the skull, there’s room for it to rattle, to be bruised or to be sheared, not only with every collision but also with every sudden stop and even start, a phenomenon sometimes described as “brain slosh.”
For athletes in contact sports, brain slosh has long been seen as inherent and unavoidable. To make progress against concussions, though, we have to give priority in future research to minimizing brain slosh during game play. This means that we need sports leagues, policymakers and health care providers to emphasize primary prevention instead of damage control.
At the National Conference on Youth Sports Safety, held in Washington in November, the approaches discussed were almost entirely focused on postconcussion management. The well-intended legislation under consideration in Congress also is too reactive. It should emphasize the critical role of primary prevention.
Newer helmets don’t seem to make much of a difference, either. Studies appearing in the British Journal of Sports Medicine and the American Academy of Pediatrics found nearly identical rates of sports-related concussions among different helmet brands and models, including older helmets and new. Why?
Think about shipping fragile porcelain — do we use steel or titanium containers, or Bubble Wrap? The same principle applies when protecting the brain. Helmets fulfill their primary purpose of preventing skull fractures and lacerations, but they do not reduce concussions. It is the delicate brain within the skull that is damaged because it does not fit snugly. Athletes would benefit from a tighter fit for the brain, a Bubble Wrap effect, during play, but what are the factors within our control that might provide that effect?
We have some leads. At the Cincinnati Children’s Hospital Medical Center, we conducted a study that suggested that high-school football players who play at higher altitudes sustain a 30 percent reduction in total concussion incidence. We hypothesized that higher altitude increased the volume in the cerebral venous system, a natural Bubble Wrap that surrounds the brain, and that this created a snugger fit inside the skull that protected the athletes from sustaining concussions. We are analyzing NFL concussion data from the 2012 and 2013 regular seasons to see if this effect holds among professionals.
There are also biomechanics in nature worth exploring for today’s athletes.
Bighorn sheep ritually ram their heads into each other and woodpeckers slam their heads against trees thousands of times a day, with neither species sustaining concussions or even much of a headache, as far as we know. Meanwhile much lesser forces result in a concussion, or worse, in humans. Our analysis suggests that both woodpeckers’ and bighorns’ brains are naturally protected with mechanisms that slow the return of blood from the head to the body, increasing blood volume that fills their brains’ vascular tree and creates the Bubble Wrap effect.
We have observed that the woodpecker uses muscles to do this, while the sheep has hollow pneumatic horn cores attached to its respiratory system that allow it to rebreathe its air and thus increase carbon dioxide in its bloodstream, expanding its intracranial vascular tree and enhancing the Bubble Wrap effect.
Every week, the lights come on over fields of competition around the world, brightening the lives of players and their fans. Unfortunately, every week the lights dim for too many athletes who suffer the effects of concussions, despite rule changes and newer helmets. What’s troubling for sports enthusiasts is that parents and politicians may be making the decision to limit or remove the opportunity for young people to participate in contact sports.
Although we cannot play every game in Denver, the winning strategies for defeating the concussion crisis may come from research focused on recreating the safe biomechanics already in use in the animal kingdom.
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