1.   Aikman played in the Super Bowl last January after a serious concussion hospitalized him after the NFC Championship game against San Francisco.

2.   He hit his head on the night stand and suffered a serious concussion.

3.   Johnson, who missed most of last season after suffering a serious concussion, is expected to notify the club with his decision sometime this week.

4.   Vujtek has suffered a number of injuries in recent year, including a serious concussion.

5.   He had at least two serious concussions two seasons ago while playing for Long Beach in the International Hockey League.

6.   Most of the injuries were serious concussions and burns, they said.

7.   San Diego Chargers quarterback Stan Humphries is ready to announce his retirement nearly four months after suffering the most serious concussion of his career.

8.   The attack sidelined Brashear for the season with a serious concussion.

9.   The officer, who was wearing a helmet, suffered a serious concussion, and the suspect disappeared into the crowd when other officers rushed to her aid.

10.   Considered a non-lethal weapon, they can break bones and cause serious concussion but rarely cause death.