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Concussion in Sports – Past, Present and Future

By Javier Cardenas, M.D. on October 26, 2017 hst Print

Whether it is the local newspaper or the national news, it almost seems as if a day does not go by without mentioning concussion in sports. For the better part of a decade, this issue has dominated just about every sport and at just about every level. During that time, it seems as if concussion, its definition and everything surrounding the topic has been a moving target. Below is an update of the past, present and future of concussion in sports.

Concussion Defined

Historically, concussion was defined as a loss of consciousness that occurred as the result of a direct blow to the head. This was especially true for those of us who participated in sports several decades ago. We got our bells rung, shook it off and kept on going.

Currently, concussion is defined as an alteration of neurological function that may not result in a loss of consciousness and may be due to a direct blow to the head, or a blow to the body that results in forces transmitted to the head. The result of redefining concussion is an increase in concussion incidence, concussion reporting and confusion in some cases. While almost no one would argue against removing an athlete from harm’s way in the event of a potential brain injury, it has made the diagnosis of concussion much more challenging.

The sensitivity of today’s tools is largely based on yesterday’s definition of concussion and relies on subjective elements such as symptom reporting by athletes. The future definition of concussion may rely on blood-based biomarkers that track changes in brain function. In some cases, we may find that such brain changes occur without any symptoms. These “sub-concussive” injuries will be the next challenging definition, as will the short-term and long-term risks associated with them.

Concussion Risk and Recovery

Historically, the risk of a concussion was based purely on the sport one played. As it was then, football remains the sport most at risk for concussion. However, rates of injury in female sports such as girls soccer and girls basketball outnumber their male counterparts. Currently identified risk factors for concussion include prior history of concussion and/or prolonged recovery from such injuries. Historically, a loss of consciousness was an indicator of a more serious injury and, therefore, a longer recovery. While a loss of consciousness may indicate a more serious process at the time of the injury, it does not suggest a longer recovery.

Our current understanding of risk factors for a prolonged recovery after a concussion include a history of migraine, depression, anxiety or a learning disability. While this does not preclude athletes from participation, a thorough history is important in identifying these risk factors. The future of concussion risk and recovery lies in our genetics. Both our predisposition to the injury and our bodies’ response to the injury may be predicted by such analysis.

Long-Term Risks

Historically, the long-term risks of concussion were unknown, under-reported and sometimes dismissed. Our current understanding of concussion is that there have been and can be long-term consequences
for those who suffer multiple concussions. Evaluation of former athletes’ brains demonstrates abnormal deposition of a certain type of protein (tau) associated with head trauma, defined as chronic traumatic encephalopathy (CTE). Unfortunately, there is no consensus on a definition for those who are living and may have problems with thinking, mood and motor functions.

The challenges with establishing the risk of long-term problems in today’s athletes are innumerable. For one, the definition of concussion in today’s athletes is different from retired athletes. The severity of injury is arguable different, but we do not know what that means for long-term brain health. Policies, laws and regulations have changed the way games are played and how long it takes for athletes to return to play. While we hope that this reduces the long-term risk of neurological disease, we simply won’t know until today’s athletes enter retirement.

Even though the definition, risks and long-term consequences of concussion are constantly evolving, it is clear that minimizing injury to the brain is best, especially for our youngest athletes. Efforts to reduce the incidence, frequency and immediate consequences of concussion have been successful from the professional to youth leagues. Enforcement of safety rules, modification of existing policy and continued research will answer the questions we all seek. In the meantime, we must educate and protect the youth who participate in the sports they enjoy.