minimac,

Somebody who does headbanging is asking for trouble. Just a quick look up or down is not going to cause damage. As I said before, it may strain the neck, especially if the neck has been previously injured.

The important part to this is. You can teach yourself to not respond with quick head movements. I've done it. And, once you have realized you have been startled into a quick head movement, don't repeat it. You are only reinforcing the behavior.

My best to you.