All Of It: Decoding CTE
Hosted by Alison Stewart | Released August 4, 2025 | WNYC

Introduction and Context

In the episode titled "Decoding CTE," Alison Stewart delves into the complex and pressing issue of Chronic Traumatic Encephalopathy (CTE), a neurodegenerative disease closely linked to repetitive head impacts commonly seen in contact sports and military service. The episode opens with a somber reminder of the recent tragic shooting in New York City, where a former high school football player claimed CTE as a motive—a stark illustration of the disease's potential impact on behavior and mental health.

Understanding CTE

Definition and Symptoms
At [00:09], Alison Stewart introduces Dr. Jesse Mez, an Associate Professor of Neurology at Boston University and an expert on CTE. Dr. Mez begins by defining CTE:

"CTE stands for Chronic Traumatic Encephalopathy. It's a neurodegenerative disease not unlike Alzheimer's disease. We know that it almost always occurs in the setting of repetitive head impacts, usually from contact sports or military exposure. It is a slowly progressive disease that has symptoms including cognitive impairment like memory problems, executive function problems, as well as behavior problems like behavioral dysregulation or a short fuse." ([02:02])

Executive Function Explained
Alison seeks clarification on "executive function problems," to which Dr. Mez elaborates:

"So that's things like problem solving, set shifting, being able to hold multiple things in your mind and manipulate both of them together." ([02:34])

Historical Perspective

Origins of CTE Research
Dr. Mez provides a historical overview, noting that CTE was first identified in boxers in 1928 by Martin. It wasn't until the mid-2000s that CTE was recognized in American football players, significantly expanding the understanding of the disease beyond boxing.

"CTE is not a new disease. It was first described by Martin in 1928 in boxers... In the mid 2000s, it was first described in an American football player." ([02:49] - [03:20])

Prevalence and Risk Factors

Dose-Response Relationship
A key concept introduced is the dose-response relationship between the number of head impacts and the risk of developing CTE. Dr. Mez explains:

"The more you've played, the bigger your risk... for each additional year played, the odds of getting CTE increased by about 30%... from one or two years of football all the way up to 25 plus years." ([04:34] - [05:03])

Affected Populations
CTE predominantly affects those with extensive exposure to contact sports, including high school and college athletes, with higher prevalence in professional players. Additionally, military personnel exposed to repetitive head trauma from blasts or equipment also show potential risk, though research in this area remains limited.

Personal Stories and Inquiries

Listener Engagement and Personal Stories
Throughout the episode, Alison invites listeners to share their experiences with CTE. Two notable calls provide deeper insight into the personal impact of head injuries and familial ties to neurodegenerative diseases.

1. Adrienne's Story
   Adrienne shares her husband's severe brain injury from 1989, his long recovery, and the family's history with Alzheimer's:

   "So I was wondering if a head injury and the Alzheimer's hereditary in the family can lead to this diagnosis also that this football players and everybody experiences." ([07:07] - [07:56])

   Dr. Mez responds by differentiating between single traumatic brain injuries and the repetitive impacts associated with CTE, explaining the complexities in linking head trauma to specific forms of dementia:

   "A single or even a handful of moderate to severe traumatic brain injuries is not linked to chronic traumatic encephalopathy, but it is linked to dementia." ([08:00] - [10:16])

2. Katie's Inquiry
   Katie from the Bronx asks about modifications in tackling techniques to reduce CTE risk:

   "Would that help ameliorate this impact of this high contact input impact on this Type of the CTE condition?" ([11:35] - [12:29])

   Dr. Mez emphasizes reducing the number and force of head impacts as the most effective strategy:

   "I think the best approach is to reduce the impacts... playing flag football as long as you can before moving to contact." ([12:30] - [13:33])

Richard's Question on Divers
Richard raises a unique point about whether repetitive impacts in sports like diving could lead to CTE:

"Olympic divers... they are really hitting the water at high velocity... any research on that type of sport?" ([13:35] - [14:23])

Dr. Mez acknowledges the gap in research, noting the absence of CTE cases among divers in brain banks but cautions that the sample size is too small to draw definitive conclusions.

Symptoms Onset and Behavioral Implications

Immediate vs. Long-Term Symptoms
Alison inquires about the timeframe for symptom manifestation post-impact. Dr. Mez explains the distinction between concussions and the cumulative effects leading to CTE:

"You can have a fairly big stroke sometimes and not show any symptoms at all... It's the repeated forces over many years that are important." ([14:50] - [17:03])

Behavioral Dysregulation and Aggression
When discussing behavioral symptoms, Dr. Mez notes that aggression may manifest earlier and is not solely explained by tau protein accumulation associated with CTE:

"It's likely that it's the CTE pathology is only contributing to some extent to the behavior problem... neuroinflammation, white matter injury, breakdown of the blood brain barrier." ([17:21] - [18:39])

Hope for the Future: Research and Diagnosis

Advancements in Diagnosis
Dr. Mez shares encouraging developments in diagnosing CTE during a person's lifetime, drawing parallels with other neurodegenerative diseases:

"We want to get to the same place with CTE... developing these biomarkers, either PET imaging or from cerebrospinal fluid or blood based, looking at changes in proteins." ([18:47] - [19:59])

Correcting Misconceptions
Addressing media portrayals, Dr. Mez emphasizes understanding the dose-response relationship and avoiding fear-mongering:

"It's important to understand this dose response relationship... it's a slowly progressive disease... people with these changes in their brains can still lead hopeful, meaningful lives." ([20:07] - [21:00])

Conclusion

Alison Stewart wraps up the episode by thanking Dr. Mez for his insights and encouraging listeners to continue the conversation around CTE openly and responsibly.

"My guest has been Dr. Jesse Mez... Thank you so much for your expertise and for sharing it with our audience." ([21:00] - [21:10])

Key Takeaways:

• CTE Definition: A neurodegenerative disease linked to repetitive head trauma, affecting cognitive and behavioral functions.
• Historical Context: Initially identified in boxers, with increased recognition in football players since the mid-2000s.
• Risk Factors: Higher exposure to contact sports correlates with increased CTE risk.
• Symptom Onset: CTE symptoms develop slowly over years, distinct from immediate concussion effects.
• Behavioral Effects: Aggression and behavioral dysregulation may emerge independently of tau pathology.
• Research Advances: Ongoing efforts aim to diagnose CTE in living individuals through clinical criteria and biomarkers.
• Preventative Measures: Reducing the number and force of head impacts in sports is crucial for mitigating CTE risk.

This episode provides a comprehensive overview of CTE, blending expert analysis with personal narratives to illuminate the multifaceted nature of the disease and its implications for athletes and society.