The mother of high school American footballer Zac Easter, who took his own life aged 24, tells BBC Radio 5 Live Sport more needs to be done to protect players from head traumas in sport.
Dallas Cowboys running back Ezekiel Elliott is suspended for six games after domestic violence incidents.
All but one former National Football League player in the research were found to have brain disease.
Representatives from five sports meet to discuss a "unified approach" to the prevention and management of head injuries.
Audio & Video
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