A look at the evidence: The cloudiness of CTE and the long-term effects in athletes.
– Michael Brown, PT, DPT, OCS, CSCS
I love football. I played full contact tackle football for 13 years, from 5th grade through college including a redshirt freshman year. I love what it did for me; it taught me leadership and followership. It showed me how to react in stressful situations where my actions would contribute toward an outcome. I had excellent coaches who instilled a hard work ethic and challenged my discipline. Most importantly, it fostered some of my best, lifelong friendships. I felt privileged then, and even more so now, that I was able to play a game I loved for so long.
I feel fortunate that I was never seriously injured playing the violent sport of football, seeing teammates end their playing days to ACL tears, chronic muscle strains, and broken bones. Unlike some of them, I never missed time from practice or games to a head injury.
I have yet to see the Will Smith movie, Concussion, which brought a national audience to the issue of long-term effects of repetitive head trauma in NFL players based on the research of Dr. Bennet Omalu. Doctor Omalu is a forensic pathologist who performed an autopsy of former NFL player Mike Webster and discovered neurological deterioration similar to Alzheimer’s disease. He named the disorder chronic traumatic encephalopathy or CTE.
Signs and symptoms of CTE usually begin eight to 10 years after repetitive mild trauma to the brain, according to the Mayo Clinic. The myriad of symptoms includes cognitive impairment, impulsive behavior, depression, short-term memory loss, emotional instability, all that can progress over time and can further develop into physical symptoms such as speech and language difficulties, motor impairment, problems with vision and smell, and eventually, dementia.
Last September, Frontline ran an article referencing a study by the Department of Veterans Affairs and Boston University which identified the degenerative disease in 87 out of the 91 former NFL player’s brains they examined. A difficulty in identifying CTE is that it must be done posthumously, so the brains examined in the study were of those players or player’s families that donated the brains to be studied upon likely suspicion they may have had it.
The same lab that performed the testing on NFL players found CTE in the brain matter in 131 of 166 (79%) people who played football either professionally, semi-professionally, in college, or in high school.
More recently, the Mayo Clinic published the first study linking CTE to amateur contact-sport athletes. This study looked at clinic records of 1,721 cases from the Mayo Clinic brain bank. There were 66 males who played contact sports (football, boxing, rugby, and yes, basketball and baseball). Of the 66 cases, 32% of them had CTE. None of the 198 brains of people who did not participate in contact sports had CTE.
There has also been research in the past looking for neurodegeneration (dementia, Parkinson disease, and ALS) in high school football players that found no evidence of increased risk later in life, again by the Mayo Clinic. This study did not examine brain matter in autopsies and did not look for CTE.
To further cloud the issue of CTE is conflicting initial evidence on depression and suicide. While one study shows that former NFL players have 3 times the depression rates of the general population, another general study on the cause of death amongst NFL players shows that suicide rates for NFL players is actually much lower than the general population.
Finally, there is this neurological study that looked at 45 former NFL players and found that while some of them have evidence of neurological trauma-related problems, the majority of them had normal looking brains. The authors suggest that perhaps the view that professional football “frequently leads to chronic brain damage” is overstated.
What all this evidence suggests is that the link between the presence of CTE and it’s symptoms, along with the progression to dementia, PD or ALS, is not yet well understood. While the link between contact sports and concussions is evident and short-term and long-term effects are being better understood, the epidemiology of concussions and CTE in athletes and the general population is still unclear. Like many health conditions, more work needs to be done to draw definite conclusions to better understand how a behavior can have an effect on one’s life.