Should Helmets Be Required? The Danger of Repetitive Brain Injury

Chronic traumatic encephalopathy, a serious disorder linked to blows to the head, is affecting athletes and even the kids who look up to them.

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Almost a century ago, a rare but serious form of dementia was linked to repetitive head injuries in boxing. The dementia was aptly named Boxer's dementia. Lately, this "punch drunk" dementia has been found to affect athletes in other sports, such as American football and soccer, where athletes' heads take repeated blows, so a broader term for this condition was needed.

Chronic traumatic encephalopathy (CTE), is a related brain disorder that has been shown to affect other kinds of athletes, and, more rarely, non-athletes who sustain head injuries. It has been in the news lately because of two high-profile cases.

Dave Duerson, a former Chicago Bears player, committed suicide last year, after having suffered from memory problems, erratic and uncontrolled emotions, and violent behavior. He left a note requesting that his brain be donated to the Boston University Center for the Study of Traumatic Encephalopathy so that it could be studied. These brain tests confirmed what he suspected: that he had suffered from CTE.

Professional hockey player Derek Boogaard was one of the youngest known athletes to be affected. After having suffered symptoms for years, Boogaard died of a drug overdose at 28. An autopsy revealed that CTE had been the cause of his neurological problems.

Brain traumas, especially chronic injuries such as those sustained in sports can, over time, lead to irreversible brain damage. There is just so much jarring and shaking the brain can take. The difficulty is that the most serious, long-term symptoms often don't show up until later in life, but clearly CTE can develop at almost any age. Here, we'll discuss the symptoms, brain changes, and prevention of CTE in athletes and in all of us.


Chronic traumatic encephalopathy affects many areas of a person's functioning, including mood, emotional regulation, cognitive capacity, memory, and personality. It often doesn't develop for years after the traumas occurred, and can present with a different constellation of symptoms in each person it affects.

Its prevalence in boxers continues. One recent review study of athletes who were diagnosed with CTE found that of the 51 confirmed cases of CTE 46 were in athletes -- and of these, 39 were boxers. Five football players, a soccer player, and a wrestler made up the remainder of the athletes affected by chronic brain trauma.

The most common initial symptoms of CTE are a variety of psychological and behavioral changes. Some experts have suggested that there are actually three phases of the disease. The first includes problems with attention, concentration, memory, and confusion; the second stage may bring with it more exaggerated behavioral symptoms like changes in social behavior, erratic behavior, and problems with judgment. Finally, the third stage can carry more severe cognitive deficits, full-blown dementia, and Parkinsonism.

Two Case Studies

A classic example is that of a retired NFL football player (all study subjects are anonymous), who started showing symptoms at age 40, when his family "began to notice minor impairments in his short-term memory, attention, concentration, organization, planning, problem solving, judgment, and ability to juggle more than one task at a time." His memory also suffered. He "repeatedly asked the same questions over and over, he did not recall why he went to the store unless he had a list, and he would ask to rent a movie that he had already seen."

Another CTE sufferer was a boxer whose short career began at 17 and ended at 22. He'd had an unrelated head injury in his teens. He started having problems with memory in his mid-20s, and in the next decade he had occasional falls and problems with confusion. His symptoms remained fairly steady for the next several decades, but they became more pronounced at the end of his life, at the age of 80.

Other research has shown that blows to the head in soccer can, over time, produce changes similar to those of CTE. The same is true for other head traumas, like head banging and repeated blows to the head from domestic abuse (more on this later). Although athletes appear, at least at the this point, to make up the majority of CTE patients, there's no reason that other types of recurrent head traumas would not pose similar risks.


The brain changes accompanying all forms of dementia are still being worked out. Amyloid-beta plaques and the accumulation of tangled bundles of protein filaments (which include deposits of the protein, tau) are hallmarks of Alzheimer's disease. Interestingly, amyloid-beta accumulation is not so widespread a phenomenon in CTE as it is in Alzheimer's. But, like Alzheimer's and other forms of dementia, CTE is marked by the accumulation of tau in certain regions of the brain. Researchers are still working to determine just why tau accumulates in the first place, and what can be done to stop it.

Autopsies of CTE patients' brains show a distribution of large and small band-shaped and small flame-shaped tangles of tau protein inside cells. These tau tangles can accumulate in the brain, similar to those seen in other dementias, but in CTE the shape of the tangles appears to be quite different from those in Alzheimer's. Tau accumulation is present in higher concentrations in certain areas of the brain in CTE, particularly around blood vessels.

Presented by

Alice G. Walton, PhD, is a health journalist and an editor at The Doctor Will See You Now.

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