The U.S. Centers for Disease Control and Prevention estimates that 300,000 sports-related concussions occur yearly in the U.S., but that number includes only athletes who lost consciousness.
Det amerikanske Centers for Disease Control and Prevention (CDC) estimerer at 300.000 sportsrelaterede hjernerystelser sker hvert år i USA, men at det antal inkluderer kun atleter der været bevidstløse.