Concussions have gained a lot of notoriety in recent years especially in the sport of football. We have come a long way for diagnosing severe concussions as having your "bell rung". Now a lot more is understood about brain trauma and the long term impact. Many of the main producers of football helmets have been scrambling to make a "concussion proof" helmet. Unfortunately a concussion proof helmet will probably never be produced, but large strides have been made in helmet safety. Now that we understand the implications of concussions athletes with them are being treated much differently. Sports illustrated writes about how athletes with previous concussions can be treated as damaged goods. http://mmqb.si.com/2013/10/24/nfl-draft-concussions-jahvid-best/