How Chronic Traumatic Encephalopathy Works

The Background

After he died of a heart attack at 50, former Steelers player Mike Webster was found to have CTE.
After he died of a heart attack at 50, former Steelers player Mike Webster was found to have CTE.
Sporting News/Sporting News via Getty Images

Those sensors in the football helmet and that laptop recording impacts were all part of a 2009 study conducted by researchers following the University of North Carolina football team. This is one example of the attention now being paid to the issue of CTE. It wasn't always so.

Back in 1928, Dr. Harrison S. Martland published an article in the Journal of the American Medical Association in which he identified a syndrome long noted by boxing fans, known colloquially as "punch drunk" syndrome. Symptoms included unsteadiness, mental confusion and slowing movement. Martland drew the connection between the symptoms and its cause: repetitive brain injury, an occupational hazard for boxers. Scientists consider this one of the first mentions in medical literature of the condition that would become known as CTE [source: Martland].

For the rest of the century, CTE was thought to be limited to boxers — a rare condition affecting a small minority of the population. For more than 80 years we've known that if you're a serious competitive boxer your chances of developing dementia are much higher than they are for the general population. In the 1950s, some medical professionals called for the sport to be banned, but their voices went unheeded. Boxers kept boxing, and fans kept watching [source: Gladwell].

Then, in 2002 a coroner and neuropathologist named Bennet Omalu autopsied Mike Webster. Webster, a retired center for the Pittsburgh Steelers, was a Hall of Famer who died of a heart attack at age 50. When Omalu looked at the former footballer's brain, there was an abundance of tau proteins. Found in people with Alzheimer's, tau proteins build up in brain cells and shut them down. But in Alzheimer's, tau usually shows up alongside another protein called beta-amyloid, which, the theory goes, sets the stage for tau proteins to do their work and produce the second, critical phase in which the symptoms of the disease appear.

In Webster's case, there was tau but no beta-amyloid, which meant Webster had dementia, but not Alzheimer's. The presence of tau had been caused by repeated head trauma, and Omalu diagnosed CTE. It was the first time a former NFL player was found to have the disease. It was not the last [source: Gladwell].

Since then, Omalu and a leading neuropathologist named Ann McKee have discovered that Webster's case was not isolated. CTE is endemic to the sport of football.

Football is, of course, wildly popular, and unlike boxing, it's a sport played by millions of people from grade school through college. That's why CTE is making front-page headlines. It's not just a question of whether it's ethically OK to watch NFL gladiators hammer one another in the head; it's also a question of whether we're putting our children at risk by letting them trot out to play for their high school team.

And it's not just football that puts people at risk of CTE. The condition has been found in people who've participated in wrestling, soccer, baseball, hockey, rugby, karate, horseback riding, parachuting, lacrosse and skiing. Some epileptics and domestic abuse victims have also been diagnosed with CTE [source: McKee et al.].