Growing up, I was never a big football fan. I didn’t care to watch the NFL on television (not even the playoffs or the Super Bowl) and I rarely went to watch my high school team play on Friday nights (except for homecoming). This isn’t to say I wasn’t a sports aficionado, but I preferred more individually oriented sports like tennis, cross-country, and martial arts. In fact, it is only in the last five years or so that I have developed an interest in the game – largely as a result of marrying into a family of rabid Buffalo Bills supporters.
As a public health practitioner and bioethicist, however, I have a morbid fascination with football and other high-impact sports. This is because these sports – football, soccer, hockey, and boxing in particular – are increasingly linked with a condition known as chronic traumatic encephalopathy (CTE).
CTE is a progressive neurodegenerative disease characterized by impaired speech, deafness, amnesia, depression, anger, and dementia. It is commonly found in military veterans and others with a history of severe head trauma. We also now know that a significant percentage of amateur and professional athletes are likely to be suffering from CTE, largely as a result of the repeated concussions that are common in competitive sports.
Concussions – known clinically as mild traumatic brain injuries (MTBIs) – occur when a blow to the head or body, a fall, or some other impact causes the brain to smash into the skull. They are one of the most frequent brain injuries, occurring more than 1.5 million times a year in the United States; 100,000 of these annual injuries occur in football alone, usually at the professional, collegiate, and high school levels.
Depending on the severity of the blow, the symptoms of a concussion can range from a mild headache, blurred vision, and some disorientation to a loss of consciousness, convulsions, and transient amnesia. These symptoms usually subside in a few hours, but they can last for days or even weeks in cases of severe or repeated concussions. There is no real treatment for a concussion other than complete physical and cognitive rest.
The association between concussions, particularly repeated concussions, and long-term neurological damage is well established. One early study of men who had a history of repeated concussions found that 80 percent showed evidence of chronic traumatic encephalopathy or other neurological disorders; most of these men had played football in high school, college or professionally. More recently, in a study published this week in the Journal of the American Medical Association, researchers examining the brains of 202 deceased football players found that a startling 87 percent had CTE. Among professional athletes, over 99 percent were diagnosed the neurodegenerative disease; of the 111 NFL players enrolled in the study, only one did not have signs of CTE. Among former collegiate players, 91 percent were found to have CTE. Most worrisome, even among those who only played football in high school, nearly a quarter tested positive for that disease. Admittedly, this study looked at brains donated by the families of deceased athletes, many of whom may have suspected that their loved ones had chronic traumatic encephalopathy, so the actual rate of CTE among living athletes is still unknown.
This is in part because a definitive diagnosis of CTE can only be made after death. During autopsy, medical examiners look for a reduction in brain weight, along with characteristic atrophy (or shrinkage) of the frontal and temporal lobes. They also look for the accumulation of a protein called tau in the regions of the brain that control mood, cognition and motor function. Tau is one of the abnormal protein deposits found in the brains of people with Alzheimer’s disease, although the pattern of tau distribution is different from that seen in those with CTE.
Although CTE can only be confirmed by post-mortem neuropathological analysis, scientists at the University of California, Los Angeles (UCLA), have begun to adapt a technique used to assessing neurological changes associated with Alzheimer’s disease to look for CTE in living patients. This technology, which uses positron emission tomography (PET scans) to measure tau accumulation in the brain, is starting to give us a sense of just how widespread the problem is.
When the UCLA researchers used this technique to examine the brains of professional athletes, patients with Alzheimer’s, and healthy controls, they found that a significant percentage of athletes – even those without a clear history of repeated concussions – showed evidence of CTE. Athletes who had experienced more concussions had higher levels of tau accumulation. Compared with healthy people and those with Alzheimer’s, the former athletes had higher levels tau accumulation in the amygdala and subcortical regions of the brain, which are the areas that control learning, memory, behavior, emotions, and other mental and physical functions.
It is clear from these and other studies that concussion, and the long-term neurological damage that results from these traumatic brain injuries, is a serious problem in football and other high impact sports. Although professional leagues like the NFL have begun to put into place new rules designed to reduce the frequency of concussions among players, the risk to athletes at any level (professional, collegiate, high school, and even pee wee) remains great.
[This blog entry was originally presented as an oral commentary on Northeast Public Radio on July 27, 2017, and is available on the WAMC website.]