Concerns about the long-term effects of concussions and head injuries have been on the rise, especially among athletes and stakeholders in contact and collision sports. With the term “CTE” (chronic traumatic encephalopathy) frequently mentioned, many are left wondering if repetitive head impacts truly cause this degenerative brain disease. A 2022 study sparked heated debates by suggesting that repeated head injuries in sports were the direct cause of CTE. But is that conclusion accurate?
This blog takes a closer look at the evidence, the ongoing debate among scientists, and what we know about head injuries in sports.
What Is Chronic Traumatic Encephalopathy (CTE)?
CTE is a brain disease that has been primarily linked to repetitive head trauma. It is often seen in athletes involved in contact sports like football, boxing, and hockey. The disease can only be definitively diagnosed after death, through an autopsy where neuropathologists examine microscopic changes in brain tissue.
The symptoms of CTE often resemble other neurodegenerative diseases such as Alzheimer’s or dementia, making it difficult to differentiate between them. This lack of clarity has made it challenging for scientists to reach a consensus on what truly causes CTE.
The Debate: Do Repetitive Head Injuries Cause CTE?
A 2022 study claimed that repetitive head injuries in sports were the definitive cause of CTE. This finding was significant because it was widely cited by other researchers and even used in an Australian Senate inquiry into concussions and head trauma in sports. Headlines from the study sparked concerns about the safety of playing contact sports, especially for young athletes.
However, a deeper analysis of the study, published in Sports Medicine, reveals that the issue isn’t as straightforward as the headlines suggested.
The Grey Area of CTE Diagnosis
One of the major challenges with CTE is that experts do not fully agree on how to diagnose or measure the disease. In a 2021 study, eight neuropathologists were asked to examine brain tissue slides from 17 cases. They were supposed to assign each case to one of four stages of CTE. Surprisingly, for 11 of those cases, the neuropathologists disagreed on the stage of the disease. In one case, all four stages of CTE were reported by different experts.
This disagreement underscores the difficulty in accurately diagnosing CTE and raises questions about the conclusions drawn from studies that claim repetitive head injuries are a definitive cause.
Similarities with Other Neurodegenerative Diseases
The symptoms of CTE such as memory loss, confusion, aggression, and depression are not unique to the disease. They are similar to symptoms of Alzheimer’s and dementia, both of which have unclear causes despite years of research. In fact, a recent update by The Lancet on dementia prevention suggested that traumatic brain injury is just one of 14 potentially modifiable risk factors for dementia. Others include smoking, obesity, lack of physical activity, and alcohol consumption.
Given these overlaps, it is crucial that research into CTE also considers other potential contributing factors instead of solely focusing on repetitive head impacts.
What Are Repetitive Head Impacts?
The 2022 study defined repetitive head impacts as “the cumulative exposure to recurrent concussive and subconcussive events.” However, it didn’t clearly define what constitutes a repetitive head impact, and accurately measuring such events is notoriously difficult.
Typically, researchers rely on self-reported data from athletes or their families. They ask about past head injuries, how long the athletes played, and at what level. The problem with this approach is that it relies on memories, which can be fuzzy, especially when recalling events from many years ago.
New technologies, such as “smart” mouthguards, which measure head impacts in real time, and video analysis of potential injuries, are starting to provide more reliable data. Studies using these tools will be essential for understanding the long-term health impacts of head injuries in sports.
What the Research Found
In the review published in Sports Medicine, researchers concluded that it is incorrect to state that repetitive head impacts are the direct cause of CTE based on the available evidence. While repetitive head trauma may be a contributing factor, the current research is not robust enough to make definitive claims.
This does not mean that head injuries are harmless, but rather that we need more rigorous studies with agreed-upon definitions and measurement tools to fully understand the risks.
Moving Forward: What Needs to Be Done
- Better Definitions and Measurements: The scientific community needs to establish clear definitions of both repetitive head impacts and CTE. Without these, it is difficult to make accurate claims about cause and effect.
- More Comprehensive Research: Future studies should explore a range of risk factors for CTE and other neurodegenerative diseases. Factors like alcohol use, smoking, and obesity should also be considered, not just head injuries.
- Technological Advances: Technologies such as smart mouthguards and video analysis should be used to gather real-time data on head impacts. This will lead to more accurate findings than relying on memory-based surveys.
- Caution in Communication: Researchers must be careful not to overstate their findings. Public discussions around CTE should reflect the fact that the science is still evolving.
What Does This Mean for Athletes?
It’s essential to recognize that the risks of concussion and head injury for everyday athletes are different from those of professional athletes. Contact sports have been implementing new safety measures to protect players, such as better concussion protocols, advanced identification methods, and improved management of head injuries.
While professional athletes may face higher risks due to their level of play, the vast majority of people who participate in contact sports lead happy, healthy lives without suffering long-term neurological damage.
Conclusion: Stay Active, Stay Safe
For now, the evidence linking repetitive head injuries to CTE remains inconclusive. More research is needed to determine the exact causes of CTE and other neurodegenerative diseases. However, staying physically active through sports is a crucial part of maintaining a healthy lifestyle. As sports organizations continue to develop safer practices, athletes can take comfort in knowing that their health is being prioritized.