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As with so many public health problems, we face the dilemma of making choices in the face of uncertainty about risks of potentially devastating proportions.”

Jim Hyde, Contributor

I was skiing alone on a wide open slope when I fell and hit the back of my head. I was momentarily “stunned.” I was wearing a helmet. Another skier came by and asked if I needed help. I then did three stupid things: First, I said “No, I just need some time to rest.” Second, I got up feeling a bit woozy and skied down the hill on my own. Third, just to prove to myself I was fine, I did another run before quitting for the day. I felt “strange” for the next four or five days but never sought medical attention. I gradually got better. I was lucky.

Interestingly, skiing/snowboarding are ranked 10th among the top 20 causes of head injury seen in U.S. emergency rooms. Cycling is number one, followed by football, baseball and basketball. Soccer is seventh on the list, horseback riding 11th, and hockey and lacrosse 14th and 19th respectively. The list for children under 14 years of age is roughly the same.

Head injury can occur in many different ways: a blow to the head from falling off a bicycle, being hit by a projectile like a golf ball or puck, running into a goal post, a car crash or, in my case, skiing. Injury occurs when the forces from the impact are transferred to the skull and subsequently to the brain. When your head hits the ground in a fall, a lot of energy must be absorbed as the mass of your head decelerates. This is what causes external injury to tissues, leading to swelling and a bump on the head.

But a second collision inside the skull also occurs due to rapid deceleration. Your brain continues to move in the original direction due to inertia. Subsequently it collides with the inside of the skull. A third impact may also occur in which the brain recoils back in the opposite direction and collides with the opposite side of the skull, potentially causing more injury.

Helmets are designed to absorb a lot of this energy. Importantly, helmets protect not just the outside of your head but mitigate the forces that cause injury inside your head from the second and third collisions.

The term “concussion” gets thrown around a lot both on and off the field. But it turns out that in less severe cases there are no real objective tests that can be applied to rule in or out a concussion. It’s often a subjective assessment based on a clinical examination.

If you are lucky your body and brain will likely recover from this insult without any lasting effects. But if the force of impact is great enough you may well lose consciousness and experience lasting effects: headache, blurred vision, loss of fine motor control. If these forces are too great you may even suffer a bleed inside your skull. This is why someone with a possible concussion needs to be seen by a health professional and carefully monitored.

The danger of repetitive impacts to the head and neck
One-of-a-kind head injuries occur to everyone from time to time. They are part of growing up and part of everyday life. The best we can do is try to avoid situations likely to lead to injury, wear protective equipment (helmets, mouth guards, eye protection) and seek medical attention if injuries occur.

However, repetitive impacts to the head and neck are especially worrisome. A study in Neurology Reviews found that varsity football and hockey players sustain an average of 1,000 hits per season, admittedly not all to the head, with an average acceleration of 20Gs (20 times the force of gravity). You may also have read that just last month the Journal of the American Medical Association reported that 110 of 111 deceased NFL football players showed clear signs of structural brain damage, CTE (chronic traumatic encephalopathy). This follows many reports of depression, cognitive impairment and suicide in former NFL players as young as 30 or 40 years old.

But the coverage of the NFL/CTE story obscures the fact that these effects likely extend well beyond professional football. After all, researchers only studied men who already had behavioral signs of brain injury. While professional football may be an extreme example, there are many sports and occupations where the risk of repetitive blows to the head and neck are common, including soccer, lacrosse and hockey. What about female athletes or racing car drivers? What about children and young adults whose brains may be especially vulnerable to damage? Are athletes who compete in contact sports at the college level at risk as well? What about the casual weekend sports enthusiast?

How to respond in the face of uncertainty
Currently no reliable screening or diagnostic tests can detect incipient CTE in living participants. Hence, as with so many public health problems, we face the dilemma of making choices in the face of uncertainty about risks of potentially devastating proportions. For most, locking ourselves in a room and eschewing all contact with the outside world is not an option. What are steps that we might take while we wait for definitive answers?

  1. Before you do anything read “Sports-related Head Injury” by the American Association of Neurological Surgeons. Written in lay language it will provide you with an excellent overview of head injury issues.
  2. Some sports pose higher risks of repetitive head injury than others. If the activity you or your child wants to pursue carries a high risk of repetitive head injury, like football, consider pursuing another activity or sport.
  3. Use protective headgear at all times knowing it is a last line of defense and not the first. Make sure helmets meet NOCSAE or ATSDM standards (see nocsae.org).
  4. Check that organized athletic programs, whether school, college or professional, are run by credentialed and certified professionals. These programs should have rigorous safety protocols and easy access to medical professionals to assess injuries when and if they occur.

Finally, moral and ethical issues further complicate matters. If you are a fan, before you pick up your remote consider this: Does buying tickets, attending games, or watching games on television make me an “enabler”? Am I aiding and abetting an industry that derives financial benefit from a product that entertains but also potentially harms and debilitates its participants? I’ll leave it to you to decide.

Jim Hyde is associate professor emeritus at the Tufts University School of Medicine. He lives in Charlotte.