As another major medical institution acknowledged the link between concussions and C.T.E., a group of scientists who guide many of sports’ top governing organizations dismissed the research at its conference.
Demaryius Thomas had C.T.E. when he died in December at 33, but the posthumous diagnosis alone does not explain what role football had in the charismatic N.F.L. star’s quick decline.
Scott Vermillion, a former college star who played four seasons in M.L.S., died in 2020. He is the first American professional soccer player with a public case of C.T.E.