Chronic traumatic encephalopathy, known as CTE, was found in 99% of deceased NFL players' brains that were donated to scientific research, according to a study published Tuesday in the medical journal JAMA.
The neurodegenerative brain disease can be found in individuals who have been exposed to repeated head trauma. The disease is pathologically marked by an buildup of abnormal tau protein in the brain that can disable neuropathways and lead to a variety of clinical symptoms. These include memory loss, confusion, impaired judgment, aggression, depression, anxiety, impulse control issues and sometimes suicidal behavior.
It can only be formally diagnosed with an autopsy, and most cases, although not all, have been seen in either veterans or people who played contact sports, particularly American football.
"There's no question that there's a problem in football. That people who play football are at risk for this disease," said Dr. Ann McKee, director of Boston University's CTE Center and coauthor of the new study. "And we urgently need to find answers for not just football players, but veterans and other individuals exposed to head trauma."
The JAMA study is the largest of its kind and all of those studied were required to have football as their primary exposure to head trauma. The criteria for submitting a brain was based on exposure to repetitive head trauma, regardless of whether that individual exhibited symptoms during their lifetime.
The study points out potential bias because relatives of these players may have submitted their brains due to clinical symptoms they noticed while they were living. It also acknowledges the lack of a comparison group that represents all individuals exposed to college-level or professional football. Without that, the study lacks an overall estimate on the risk of participation in football and its effects on the brain.
