Hello! I have been lurking, mostly in the classifieds. I was not going to join until I made the decision to pick up a Hayabusa, but based on having real problems in life, and on the other side having parents and siblings who consistently repeat the same motorcycle death stories every time I see them, I have strong feelings on this topic.
I have chronic pain and the vibrations of the motorcycle are an effective aspirin. Vibration therapy is proven to calm the nervous system and reduce pain. Thus I can tell people honestly that the motorcycle helps to temporarily alleviate chronic pain. From my experience I suspect that others who get a high from riding are getting a direct physiological stimulation from the bike, and not just an emotional thrill. Someone needs to measure and quantify that though to prove it.
So tell the doctors this. Ask them how robustly have they studied the effects of motorcycling. Present this as a project for the hospital's research group. If they dismiss it, then use this: "You see people in chronic pain daily. How could you possibly dismiss this?"
As you know motorcycling is very physical, unlike the act of driving a car. I would respond that motorcycling is your perpetual workout routine. How on earth is a medical professional going to disparage that?
I believe in living via knowledge and not feelings. Feelings betray people. So beat them senseless with knowledge in their own academic area.