The problem is you cannot prevent injury by wearing a helmet. You cannot prevent brain damage from occuring by wearing a helmet. My injury occurred without my head impacting anything. Yet, it took months for me to recover.
Based on my experience, I fear more for those who believe the helmet "saved" them and do not see a doctor after an accident, than I do for those who do not ride with a helmet.
Also, based on my experience, I do not take too seriously a comment from a paramedic or ER doctor...who states as fact that death would have been the result if a helmet had not been present....since I had a brain injury and each missed all the symptons and signs. If they don't understand brain injuries and how they occur, their remarks are simply opinion. For me, since I had no external injury, the doctors I first visited believed I had no head injury and released me.