Potential Consequences to Repeat Concussions

With the growing attention on sports-related concussions, greater light has been shed on the condition known as chronic traumatic encephalopathy (CTE). There is now evidence that multiple or repeat concussions may lead to progressive neurological issues. There is even concern that sub-concussive injuries (i.e., those where minimal or no symptoms occur) may add up over time to contribute to the development of CTE in the future. While only recently making major headlines, CTE is not a new entity, having been known to affect boxers as early as the 1920s. At that time it was referred to as “dementia pugilistica.”1 Over the past few years, CTE has been publicized most prominently with regard to professional American football players; however, the NFL is far from the only sports organization dealing with this issue. There is growing concern that CTE may affect football players relatively early in their careers—as early as during collegiate participation. Others sports where greater attention has been directed to this problem include hockey and soccer.2,3

While the exact mechanism of the development of CTE is not fully understood, it is thought that repeated head trauma may lead to chronic damage to some of the vital proteins that aid in brain function. Abnormalities in the shape and function of these proteins, especially the protein called tau, may lead to overall dysfunction and potentially even brain cell death. Diagnosis is currently possible only after death, with an autopsy. There is much work being done to learn how to diagnose CTE in the living. This would aid tremendously in awareness, treatment, and prevention.

Symptoms of CTE can appear during, relatively soon, or long after the individual stops playing competitive sports and can include cognitive (thinking), physical, and emotional issues and vary widely in their severity and impact on the individual. Perhaps the most stark example of the potential severity of issues that arise from CTE is shown in the autopsies of athletes who have committed suicide, highlighting the need for greater understanding, prevention, and treatment of the problem.

While repeat head injury, leading to concussive or even sub-concussive episodes, is thought to be the main culprit of CTE, we currently do not know which athletes are most at risk. There are ongoing research studies which are aiming to define categories of athletes who may be at a higher than average risk for developing CTE, such as those with pre-existing learning disabilities, and those who have persistent lingering symptoms after a concussion.4

With the recent increase in our understanding of sports-related traumatic brain injury and CTE, there’s been increased attention to diagnosis and management of concussion, including implementation of concussion

protocols in many sports. Hopefully, these strategies, along with improved education of athletes, trainers, coaches, parents, and medical providers, will result in better outcomes after sports-related head injuries and safer return to play.

References 1. Martland, HS. Punch-drunk. JAMA. 1928. 19:1103. 2. Matser EJ, Kessels AG, Lezak MD, et al. Neuropsychological impairment in amateur soccer players. JAMA. 1999. 282:971. 3. Matser JT, Kessels AG, Jordan BD, et al. Chronic traumatic brain injury in professional soccer players.Neurology. 1998; 51:791. 4. Giza CC, Kutcher JS, Ashwal S, et al. Summary of evidence-based guideline update: evaluation and management of concussion in sports: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2013.80:2250.