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.
Pavle Jovanovic, who represented the United States at the 2006 Olympics, is believed to be the first athlete in a sliding sport to be found with a disease caused by repeated brain traumas.