Dave Duerson, the former Bear who committed suicide this year, was the 15th NFL player whose brain was examined by Boston University researchers, and the 14th who was found to have the brain damage known as chronic traumatic encephalopathy. But that doesn’t necessarily tell the researchers a whole lot.
The problem researchers are having, as detailed by Alan Schwarz in the New York Times, is what’s known as selection bias — the players and families of players who are donating their brains are the ones who suspect they have the condition. Players who haven’t suffered from memory loss, depression or other problems aren’t donating their brains, and therefore there’s no control group in the study.
“What we desperately need is what one would call healthy brains,” said Dr. Robert Cantu, a co-director of the group studying brains. “If those have CTE, then that opens up lots of other questions.”
Dr. Ann McKee, the lead neuropathologist for the group studying players’ brains, noted that brains from people who aren’t experiencing any symptoms have been hard to come by.
“A family is much more likely to donate the brain of a loved one if they have even the smallest suspicion that something was wrong,” McKee said. “If they were perfectly confident that they were functioning 100 percent normally, they’re much less likely to go through the process.”
So what the researchers need is to study the brains of a wider cross section of donors. And they’re asking for more players to pledge their brains.