Are you ready for Super Bowl LI? After learning about sub-concussive hits, concussions, and post-concussive symptoms, perhaps you’ll find yourself watching next week’s game in a whole new light! I know that I’ve certainly become more attuned to the plays and strategies used in football, not to mention the not-so-subtle interactions... Yet, I was still surprised by the findings from a recent study published in the New York Times that shared information that was gathered from a sensor in an offensive lineman’s mouth guard. The data indicated that over the course of a single college football game, this player sustained 62 blows to his head. 62! It was further estimated that these blows were equivalent to the force of crashing a car into a wall at 30 miles per hour. Given this information, it’s clear how concussive events might occur, even without experiencing a direct hit to the head. When your body makes impact with another person and/or the ground with that much force, you will inevitably suffer some degree of whiplash and functional brain disturbance.
The effects of a concussion typically include physical problems (e.g. headache, dizziness), cognitive dysfunction (e.g. memory loss, confusion), and emotional symptoms (e.g. depression, irritability). However, these problems do not always manifest immediately upon sustaining an injury. I realize that this sounds counterintuitive. In other words, how can a person seem fine within minutes after hitting their head and then report severe discomfort the next day? The answer is actually quite simple and can be illustrated with the following question: Have you ever felt okay while lifting weights at the gym only to find yourself unable to raise your arms above your head a day or two later? Well, this phenomenon is similar to what a person might experience after a concussion. It can be attributed to inflammation and other metabolic changes that occur as a result of the precipitating event. Furthermore, some athletes may not feel particularly bothered by a head injury at the time it happens, perhaps because they’ve grown accustomed to coping with pain or maybe because they’re so charged up while playing that they fail to notice their symptoms at all. Some athletes even minimize their injuries or deny them altogether so as not to affect their scholarship or salary or jeopardize their multi-million dollar contract… Can you really blame them? As a result of these factors, however, gauging the true severity of a person’s symptoms can be tricky business!
In the large majority of cases, post-concussive symptoms last from one day to two weeks. And when I say “large majority,” I mean that research studies have found that approximately 90% of adults who suffer a concussion recover within 10 days. Children and adolescents require a lengthier recovery time, but it is still unlikely for post-concussive symptoms to persist beyond a few months. Now don’t forget that I’m referring to the expected recovery for a single injury (as opposed to the cumulative effects of multiple concussions). In an effort to prevent the occurrence of longer lasting negative outcomes, sports organizations have been working closely with healthcare professionals to determine return-to-play guidelines that will better ensure their players’ safety. Whereas neuropsychologists assess brain functioning by examining the way individuals perform on standardized tests in comparison to the symptoms they report and the description of their injuries, neurologists complete a physical examination and refer to the results of neuroimaging (e.g. MRI scan of the brain). Since concussions rarely cause structural changes in the brain, however, more sophisticated techniques are being employed to determine the level of a protein called tau that is found in a person’s brain and bloodstream. As I described in a previous blog post, tau is the protein that has been most closely linked to the development of Chronic Traumatic Encephalopathy (CTE). Although the tau protein is found in everyone, injured players appear to have higher levels of it following a concussion. It therefore seems possible that serial testing for tau protein levels can give coaches an objective measure on which to base an athlete’s return-to-play status.
Return-to-play guidelines are important because (re-)injury before an athlete is fully recovered from a concussion can have devastating consequences. It’s almost like having a weakened immune system and exposing yourself to someone with a contagious virus nonetheless. Chances are high that your body won’t be strong enough to efficiently fight off a second illness. Although very rare, there have been cases reported in football players that secondary injuries have led to brain hemorrhage, swelling, and subsequent death. In less extreme cases, there is evidence that secondary injuries interfere with the brain’s healing process, exacerbate and prolong post-concussive symptoms, and potentially lead to the development of neurodegenerative disorders. There is still much to be learned about the long-term effects of sub-concussive hits and concussions. Meanwhile, it appears that risk management interventions and follow-up treatment towards promoting a complete recovery are necessary.