Concussions are a very common problem with athletes, particularl

google一下也挺多的。以前我听过两次听证会，不记得那些数据了

http://www.usatoday.com/story/sports/ncaaf/bigten/2015/03/06/coroner-ohio-state-kosta-karageorge-suicide-concussions/24525255/

http://www.suicide.org/concussions-can-lead-to-suicide.html