I think there is indeed a case of differing dispositions from player to player. I must admit I've played hundreds of footie matches from when I was a kid and I 'headed' heavy fillies in the early years and the wet balls were even heavier! I don't think I've been affected and I'm guessing that there is some form of neural recovery that kicks in even though there is a clear measured effect on impact. I'd also like to see more global data that possibly would shed more light re this issue but it appears that there's hardly been any research studies to investigate the risk of brain damage. IMO protection of young footballers is the 'do minimum' in this situation.