Yep. NFL players get concussions and bad concussions all the time. Trent did not change after that hit....it is a Bills urban legend. Trent was simply limited in his ability to see things down the field, defenses caught on and made him ineffective. It is not unusual for a QB to do well at first and then defenses take away what he likes to do, the QB becomes less effective. At that point, a QB has to evolve, Trent did not.