I've played and coached soccer for years and have had at least one concussion although I didn't realize that's what it was until years later. I'm already worried about my lo's little brain and he can't even walk yet. This is an awesome article about a quick and easy method of diagnosing concussion based on reaction times.

http://well.blogs.nytimes.com/2013/08/14/a-simple-device-to-detect-concussions/?hpw