The article is by Malcolm Gladwell, author of "The Tipping Point" and "Blink". He, in my opinion, effectively draws some striking parallels between dogfighting and football. The basic idea:
"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."
