Punch drunk syndrome

Boxing can cause chronic brain damage. In early stages it includes unsteadiness in gait and slight mental confusion, later, distinct leg dragging, hand tremors, general slowing of muscular movements, hesitant speech, nodding movements of the head, and finally, facial characteristics of Parkinson's syndrome, tremors, staggering gait and severe mental deterioration.

A boxer's fist travels at some 20 mph at the moment of impact, delivering a force of some 0.4 tons, or as a maximum roughly half a ton. Single blow or cumulative blows to head have caused at least 10 to 15%, according to other studies, 87% of professional boxers to display some or all these symptoms of cerebral dysfunction.