Concussion in sport is an issue that’s hit the headlines with increasing frequency over the last few years, but how much do we really know about the long-term effects of head injuries? What do we know so far? In short, the answer is ‘very little’. While we may recognize the short-term symptoms of a concussion, not much is known about the long-term impact of either concussions or sub-concussive head impacts (for example, when heading a football). Recent years have seen…