"Ronney Jenkins cannot be sure whether chronic traumatic encephalopathy is clawing through his brain tissue right now, but he suspects that it is."

So begins a CNN medical news report about football and brain damage.

"I'd be talking to a cousin of mine, disagree with him, and I'd just want to do something to him," Jenkins said. "I don't know why I had those thoughts, but I wanted to hurt him."

Jenkins cannot shake the feeling that these and other symptoms he has add up to CTE, but he will never be sure. The only way to diagnose CTE is after death -- by analyzing brain tissue and finding microscopic clumps of an abnormal protein called tau.