Do Concussions Cause CTE? Sports Doctors and Scientists Disagree.

But the makeup of the group itself poses apparent conflicts of interest that call into question their delay on accepting new research on concussions. FIFA; the I.O.C.; the F.I.A., which governs automobile racing leagues including Formula One; World Rugby; and other governing organizations in sports sponsor the conference and have working relationships with many of the leaders of the conference or provide them with research funding.
“This group has been led by people who don’t really have a full understanding of the pathology of head injury at that level,” said Willie Stewart, a neuropathologist in Glasgow who has diagnosed C.T.E. in many athletes. He said the conference leaders should have their terms limited. “There should be a rotation of people so they don’t have any fear of what they said four years ago.”
Previous consensus statements claimed that the science was not settled on C.T.E., and that language has been adopted by sports leagues including the N.H.L., the N.C.A.A. and New Zealand Rugby, a stamp of approval from scientists that has helped some of those organizations fend off lawsuits accusing them of hiding the dangers of concussions from athletes.
Still, researchers pushing for a recognition of a cause-and-effect relationship between head trauma and C.T.E. were initially optimistic that the group’s leaders might be swayed by new research. In March, Paul McCrory, a longtime leader of the group and a vocal skeptic of the links between head hits and C.T.E., resigned after he was caught plagiarizing.
But in conversations before and during the conference, leaders of the group centered their discussions on what was unknown about C.T.E., noting that it was unclear why some athletes got the disease and others who played the same sport did not. No one can say how much head trauma is needed to get C.T.E. A reliable test for diagnosing the disease in the living is at least five years off, experts said.
Then, in one of the conference’s final sessions, titled “Long Term Sequellae and Criteria for Retirement,” Iverson began the hourlong confab by discussing the criteria the group would use to review concussions research.