In 2006 I fell off a horse and lost consciousness. When I came round eight hours later those hours were a black hole from which no memory has ever returned. After three months my mental processing was more-or-less back to normal, but I have no way of knowing whether my cerebral function is permanently damaged.
Since then it has become clear that repeated head injury, even without unconsciousness, leads to neurodegenerative disease. Chronic traumatic encephalopathy (CTE) causes disturbances of memory, mood and orientation, thinking and decision-making. And it affects a lot of sportspeople.
It was the sad sight of the ageing Muhammad Ali that awakened the world to the dangers of repeated blows to the head. In his era, some professional boxers fought hundreds of bouts, each preceded by many rounds of sparring. Over a lifetime that’s thousands of blows to the head. Boxers expected to come out of sparring sessions with a splitting headache and to be punch-drunk by the end of their careers.
