Nearly every former NFL player who donated brain for research suffered from CTE

New findings from a study on the crippling brain disease Chronic Traumatic Encephalopathy (CTE), which is linked to individuals who sustain repeated blows to the head or who are subject to repetitive brain trauma, showed that nearly every former NFL player's brain examined during research revealed evidence of CTE.

The findings released Tuesday were part of a study conducted by two leading medical institutions devoted to CTE research - the VA Boston Healthcare System and Boston University School of Medicine - and the results concluded that of 111 NFL players' brains that were donated to science after the players' deaths, 110 (99 percent) were found to have CTE. The disease currently can only be diagnosed post-mortem.

"The most striking part of the study is just the sheer numbers (of CTE cases)," Dr. Jesse Mez, the study's co-first author and an assistant professor of neurology and science at Boston University, told the Daily News Tuesday. "In a relatively short amount of time, and without much in the way of recruitment, we were able to accumulate this large number of brains that have evidence of CTE."

The study overall included research on 202 deceased American football players, from all levels of play (high school, college, semi-pro, Canadian Football League and NFL) who donated their brains for research. Of that total, CTE was diagnosed in 87 percent (177) of those players' brains. Dr. Mez underscored that the brain bank from which this study conducted its research differs greatly from other brain banks across the country doing research on CTE.

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Hall of Famer Junior Seau was diagnosed with CTE following his 2012 suicide.
(Stephen Dunn/Getty Images)

"There is selection bias into those who donate to our brain bank - it's those individuals with a lot of football exposure and those who are symptomatic that are more likely to donate. The major difference is that we have an eligibility requirement that (the donor) be exposed to repetitive head impact," Dr. Mez said. "That starts to establish a strong link between CTE and football. We only look at football players' brains. We're rigorous in how we evaluate clinical symptoms and pathology."

The breakdown of the study -- which was indirectly funded by the NFL through a National Institutes of Health grant -- shows a high percentage of CTE cases in every level of competitive football: 7 of 8 (88 percent) CFL players; 9 of 14 (64 percent) semi-pro players; 48 of 53 (91 percent) college players; and 3 of 14 (21 percent) high school players, in addition to the NFL player statistic.

Dr. Mez said that the goal of doctors and scientists is to eventually be able to diagnose CTE among the living, so that research and development of treatment methods can be expedited. "The only way to develop therapy is being able to diagnose this disease in life," Dr. Mez said.

Former defensive back Tyler Sash, who died in 2015, was found to have suffered from CTE.
(Julio Cortez/AP)

Mez added that it's important for the public to know that this study doesn't "say definitively that there's a causal link between football and CTE," and that the media can sometimes make that connection faster without being privy to what Mez calls "a rigorous peer review process to be sure that what you're presenting is real."

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"Science is a slow process," Dr. Mez said.

He added that one of the other important findings of the study is that CTE, in a clinical sense, is very similar to Alzheimer's.

Family of Hall of Famer Frank Gifford says signs of CTE were found in his brain following his death.
(Kathy Willens/AP)

"The faster we collect brains, and the more we study, the faster we're going to get to that point of diagnosing CTE in the living," Dr. Mez said. "One of the important points is to develop bio-markers and figure out ways of differentiating this disease (CTE) from other neurodegenerative diseases, most certainly Alzheimer's."

Dr. Robert Stern, another BU neurology professor and CTE expert, told The News last year that the issue, which is sometimes buried in the CTE conversation, is that children playing an impact sport like football, when the brain is in a critical developmental stage, could be setting the stage for developing brain disease later in life. Dr. Mez said that while this latest study did not make any definitive findings about the link between CTE and youth football players, there is important data on that issue already available.

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"We see this pathology in some teenagers who are actively playing collision/contact sports. Given that we think there is a link between (sustaining) hits and the disease, it makes sense that the initiation of the process happens at the time of the hits," Dr. Mez said. "We also have data on age of onset and how that affects outcomes. But there is a giant caveat - the best way to study that question (of a link between CTE and youth players) is to start studying kids and follow them prospectively. CTE is largely a disease of the elderly."

Added Dr. Ann McKee, a corresponding author of the study and the director of BU's CTE Center: "The finding of early CTE pathology in high school and young collegiate players emphasizes the urgent need for longitudinal, prospective, multicenter studies to identify young players at risk for CTE as well as treatment strategies and comprehensive care for players who are suspected to have CTE during life. It is no longer debatable whether or not there is a problem in football; there is a problem. Through this study, we have identified meaningful opportunities for detection, prevention and multiple targets to slow or stop CTE, and it is time to come together to find solutions."