Journal of the American Medical Association: Punch Drunk
"Punch drunk most often affects fighters of the slugging type, who are usually poor boxers and who take considerable head punishment, seeking only to land a knockout blow. It is also common in second rate fighters used for training purposes, who may be knocked down several times a day."
Research Gate: Chronic traumatic encephalopathy: Neurodegeneration following repetitive concussive and subconcussive brain trauma
"Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease thought to be caused, at least in part, by repetitive brain trauma, including concussive and subconcussive injuries."