I read once an article that soccer players have reduced brain function when doing too many headers (i.e. hitting the soccer ball with your head).
A new study of long-time adult soccer players has found changes in the brain similar to traumatic brain injury as a result of repeated “headers” of the ball. The study also found an association between players who had repeatedly headed, and slight memory loss.
Is there any scientific data backing this up? Is the damage permanent or only temporary?