Concussions vs. CTE - Understanding the Difference

If you follow sports, you have probably heard of CTE, the brain disorder made infamous by American football players like San Diego Charger’s linebacker Junior Seau, football safety Dave Duerson, Oakland Raiders Ken Stabler, and football center Mike Webster. But what is CTE and what causes it? One common myth is that concussions – hard blows to the head – are the cause of CTE. However, the accumulated damage of repeated non-concussive hits to the head, involving rotational forces, leads to CTE. These rotational forces cause the brain to rotate inside the skull, shear brain cells, tear fine blood vessels, and disrupt the protective blood-brain barrier.?

In this article, we review the definition of a concussion and the definition of CTE, outline the key differences, and touch on some safeguards that players, parents, coaches, and medical professionals can consider implementing to protect athletes at all levels.

What is a Concussion?

A concussion is a type of traumatic brain injury (TBI) that occurs when a blow, bump, or jolt to the head disrupts normal brain function. Concussions are often classified as "mild" TBIs because they are usually not life-threatening. However, the effects can be serious and, in some cases, long-lasting. Common symptoms include headaches, dizziness, confusion, nausea, sensitivity to light and noise, and even temporary loss of consciousness. While most individuals recover fully with proper rest and care, the risks increase significantly with repeated concussions, potentially leading to cumulative brain damage.?

But what exactly happens inside the head? Your brain is soft, surrounded by cerebrospinal fluid that cushions it, much like gelatin in a glass bowl. When your body experiences a forceful impact—whether to the head, neck, or body—the energy from that impact travels through the skull and makes the brain shake or 'jiggle.' This movement can stretch and tear the brain's delicate axons, which are responsible for transmitting signals between neurons, leading to microscopic damage that disrupts communication in the brain. Additionally, these forces can rupture tiny blood vessels, causing localized bleeding and inflammation that further impairs brain function. Because the severity of a concussion isn't always related to the intensity of the impact, it's crucial for athletes and coaches to watch for symptoms after any significant jolt or collision.

Research from the University of Pittsburgh estimates that sports-related concussions number in the hundreds of thousands annually in the U.S. The risk is especially high for contact sports, where it's estimated that nearly one in five athletes will suffer a concussion each year. Over the course of five years, this means that most athletes in contact sports will likely experience at least one concussion, highlighting the importance of vigilance and effective management of these injuries.

Understanding CTE

Chronic Traumatic Encephalopathy (CTE) is a progressive neurodegenerative disease that poses a silent risk to individuals who have suffered repeated head injuries, including concussions and subconcussive impacts. Unlike concussions, which present immediate symptoms, CTE can remain undetected for years, often manifesting slowly over time, with symptoms emerging years or decades after the last head trauma. This “silent disease” is characterized by the accumulation of abnormal tau protein in the brain, which disrupts normal cell function and leads to cognitive decline, memory loss, emotional instability, and behavioral changes.

CTE damage is caused by rotational forces and happens in several phases: at the point of impact, on the opposite side of the brain, and when the brain comes to a stop after rotating. This movement shears axons - key structures necessary for cognitive functions such as memory and behavior - and can lead to long-term brain cell death. Over time, these microtraumas accumulate, significantly increasing the risk of CTE and other neurodegenerative conditions in athletes. Because of this, even athletes who have never been diagnosed with a concussion may still suffer the devastating long-term effects of CTE due to the build-up of these microtraumas over the course of their careers.

The symptoms of CTE can include severe memory loss, confusion, aggression, impaired judgment, depression, and, in some cases, suicidal tendencies. Lise Hudson, the wife of former New York Jets defensive back Jim Hudson, shared a heartbreaking story about her husband’s struggle with CTE. She recalled finding him at home, holding a golf ball, and crying because he no longer remembered what it was or how to play the game he once loved. "You watch the life go out of someone's eyes," Lise said, capturing the profound impact of the disease. Research has shown that the buildup of tau protein in CTE is similar to what is seen in Alzheimer’s, suggesting that CTE could lead to an increased risk of developing Alzheimer’s disease later in life.

According to research by CTE expert Dr. Ann McKee’s of Boston University, every additional estimated 1,000 head impacts increases the odds of being diagnosed with CTE by 21%. Additionally, cumulative forces exerted on the brain significantly raise the risk of CTE.

Concussions typically result from a single, acute impact that causes immediate symptoms like headaches and confusion. In contrast, CTE is driven by repeated, low-level impacts that create micro-traumas over time, often without any noticeable symptoms. Leading UK-based neuroradiologist Dr. Emer MacSweeney points out in her 2022 TED Talk, "20% of people diagnosed with CTE after life had never had a single recorded concussion. Failure to grasp this critical discovery is too common, and it presents a huge issue in understanding how we tackle CTE."?

This highlights the significance of both concussive and subconcussive impacts in the development of CTE. Because CTE symptoms can take years to appear, it often goes unnoticed until it has reached an advanced stage. Traditionally, CTE could only be definitively diagnosed posthumously through an examination of brain tissue. However, recent advancements by Re:Cognition Health, led by Dr, MacSweeney, are changing this paradigm. Using diffusion tensor imaging (DTI) alongside MRI scans, the clinic has made significant strides in diagnosing CTE in living patients. Dr. MacSweeney emphasizes that the “development of sophisticated biomarkers to identify the abnormal inflammatory markers [in the brain] associated with CTE, will hopefully enable early accurate diagnosis.” As she further states, "We are at the tip of a global CTE iceberg, and three critical areas of focus are required: brain protection, CTE diagnosis in life, and treatments."

Key Differences Between Concussions and CTE

Educating athletes, their families, coaches, and medical professionals is the frontline of defense. Once people recognize that concussions and CTE are distinct but sometimes related conditions, they can become empowered with the information they need to take steps to protect themselves and others. To recap, these are the main differences between concussions and CTE.?

1. Nature of Injury:

• Concussion: An acute and immediate injury resulting from a single traumatic event.
• CTE: A chronic condition that develops over time due to repeated rotational subconcussive forces that create micro traumas that accumulate over time.

2. Symptom Onset:

• Concussion: Symptoms appear shortly after the injury and can include headaches, confusion, and dizziness.
• CTE: Symptoms develop gradually over years, often starting with mood changes and memory problems.

3. Recovery vs Progression:

• Concussion: With proper treatment and rest, most individuals recover fully from a concussion.
• CTE: CTE is a progressive disease with no known cure. With new information and data, we are realizing we have a dire need for CTE protocols and practices.

4. Diagnosis:

• Concussion: Can be diagnosed through clinical evaluation and imaging, such as MRI or CT scans.
• CTE: Historically only diagnosable posthumously through brain tissue examination. However, advancements in neuroimaging techniques, such as diffusion tensor imaging (DTI) combined with MRI scans (coupled with clinical evaluations) have enabled early diagnosis in living patients. Emerging biomarkers and functional MRI are being developed to detect abnormal tau protein and inflammatory markers in the brain.

Creating a Future Safe From CTE

The growing body of research linking concussions and subconcussions to the development of CTE has profound implications for athletic safety, particularly in contact sports like football, hockey, soccer, rugby, and boxing. The only known way to address CTE is to prevent it from developing in the first place. This means minimizing repeated, non-symptomatic impacts that can accumulate and lead to long-term brain damage. Sports can still provide immense physical and mental benefits, such as teamwork, discipline, and physical fitness, without compromising brain health. By implementing protective measures, improving training techniques, and focusing on reducing unnecessary contact, we can preserve the positive aspects of sports while preventing the risk of long-term disease.

To create a safer future, we must focus on several key principles. First, education is essential—raising awareness about the risks of CTE and the importance of early detection ensures that everyone involved in sports understands the potential long-term consequences of the accumulated damage of head trauma. Additionally, measuring the strength and frequency of impacts allows for better monitoring and management of injuries over time.

Changing the way we practice and play is also crucial. By modifying training routines to reduce the likelihood of head impacts and advocating for rule changes that emphasize player safety during games, we can significantly decrease the risk of CTE. Finally, we recognize the importance of protecting younger athletes. Their developing brains are more vulnerable to injury, so it’s vital to set age-specific guidelines for contact sports participation to limit head impacts.

By embracing these principles, we can work toward a future where athletes are better protected from the risks of CTE, keeping sports safe and enjoyable for all participants.

Cogwear is a brain technology company that improves health, peace, and performance through comfortable, wearable technology for better brain insights. Our technology provides real-time, clinical-grade physiological feedback for athletes. Our team is partnering with Rezon, a UK-based company that offers protective athletic headbands designed to help players stay in top shape “above the neck”. Together, we are creating a new digitally-enabled headband that helps athletes and coaches make informed decisions on and off the field.?

Additional sources

• International Concussion Society. (2019, August 6). The relationship between concussion and CTE. Concussion.org. https://concussion.org/news/concussion-and-cte/
• Concussion and CTE. (n.d.). https://nationalconcussionawarenessday.com/uploads/3/6/1/8/36181025/web_concussion_cte_fact_sheet.pdf
• Advantage Healthcare Systems. (2024, August 28). Is CTE different from concussion? - advantage health care. https://www.advantagehcs.com/is-cte-the-same-thing-as-a-concussion/