Dementia pugilistica: football's dirty little secret
Can’t remember which football teams you’ve played for? Forget who you defeated in that boxing ring? Dementia pugilistica may be to blame. Also known as Boxer’s syndrome, this type of Alzheimer’s Disease-like dementia is caused by repeated head trauma – like that experienced by boxers and football players. And apparently, dementia pugilistica could also be a risk of dogfighting, too. The image above (from Medscape.com) shows brains injured from repeated head trauma.
While neurologists and neuroscientists have been aware of this form of dementia for decades, only recently has the topic hit the mainstream press. Malcolm Gladwell’s piece for the New Yorker in October 2009 exposing the striking similarity between dog fighting and football has been listed as one of the best articles of the year. And just today, the New York Times is running an Op-Ed piece publicizing (concurrent with the run-up to the Superbowl and congressional hearings on football-related concussions) of all things, an article from the Journal of the American Medical Association (JAMA) from 1928. In part, it warns:
“There is a very definite brain injury due to single or repeated blows on the head or jaw which cause multiple concussion hemorrhages. ... The condition can no longer be ignored by the medical profession or the public.”
While Alzheimer’s type dementia can only be definitively diagnosed by post-mortem examination of the brain, and staining for trademark beta-amyloid plaques and tau-containing neurofibrillary tangles, Alzheimer’s and other forms of dementia may exhibit similar symptoms in terms of patient behavior and memory loss. Gladwell writes of a patient in an Alzheimer’s ward, whose brain was found post-mortem to lack beta-amyloid markers, but was chock-full of tau – suggesting chronic traumatic encephalopathy (C.T.E.), or a condition that progresses into dementia pugilistica. An excerpt:
The stained tissue of Alzheimer’s patients typically shows the two trademarks of the disease—distinctive patterns of the proteins beta-amyloid and tau. Beta-amyloid is thought to lay the groundwork for dementia. Tau marks the critical second stage of the disease: it’s the protein that steadily builds up in brain cells, shutting them down and ultimately killing them. An immunostain of an Alzheimer’s patient looks, under the microscope, as if the tissue had been hit with a shotgun blast: the red and brown marks, corresponding to amyloid and tau, dot the entire surface. But this patient’s brain was different. There was damage only to specific surface regions of his brain, and the stains for amyloid came back negative. “This was all tau,” Ann McKee, who runs the hospital’s neuropathology laboratory, said. “There was not even a whiff of amyloid. And it was the most extraordinary damage. It was one of those cases that really took you aback.” The patient may have been in an Alzheimer’s facility, and may have looked and acted as if he had Alzheimer’s. But McKee realized that he had a different condition, called chronic traumatic encephalopathy (C.T.E.), which is a progressive neurological disorder found in people who have suffered some kind of brain trauma. C.T.E. has many of the same manifestations as Alzheimer’s: it begins with behavioral and personality changes, followed by disinhibition and irritability, before moving on to dementia. And C.T.E. appears later in life as well, because it takes a long time for the initial trauma to give rise to nerve-cell breakdown and death. But C.T.E. isn’t the result of an endogenous disease. It’s the result of injury. The patient, it turned out, had been a boxer in his youth. He had suffered from dementia for fifteen years because, decades earlier, he’d been hit too many times in the head.
Gladwell also writes that the rates of dementia pugilistica or C.T.E. in boxers and football players are strikingly high, especially when compared to a general population at old age:
“A long time ago, someone suggested that the [C.T.E. rate] in boxers was twenty per cent,” McKee told me. “I think it’s probably higher than that among boxers, and I also suspect that it’s going to end up being higher than that among football players as well. Why? Because every brain I’ve seen has this. To get this number in a sample this small is really unusual, and the findings are so far out of the norm. I only can say that because I have looked at thousands of brains for a long time. This isn’t something that you just see. I did the same exact thing for all the individuals from the Framingham heart study. We study them until they die. I run these exact same proteins, make these same slides—and we never see this.”
Many professional boxers, most famous of whom is probably Muhammed Ali, have been diagnosed with dementia pugilistica. Recent research has also revealed that football players are also at a higher risk of dementia due to repeated head injury. And sadly, the third example may now come from the world of dog fighting. In dog fighting, the dogs are chosen for their ability to persevere – to keep charging at their opposition even when they’re injured. And surely, risking brain damage at the same time, just like their human counterparts.
Nearly 100 years after the JAMA warning about head injuries, its about time we face facts about the risks of our spectator sports.