was the head of neurology at Temple U. We used to talk about it regarding my brother's case. I also discussed the topic, and my brother's case, with Teddy Atlas. A single punch to the head can cause damage that often progresses with age. Punches to different parts of the head cause different conditions. When we consider Ali, in the second half of his career, he took lots of "rabbit punches" to the back of the head ..... from that shitstain Chuck Wepner, for example. Or Earnie Shavers, who had unreal punching power. (My brother & I watched Shavers from ringside, and his punches were intense.)
On the other hand, we look at Smokin' Joe Frazier, who took punches to the forehead. This causes mood changes early on, and the inability to recognize another person's intentions upon meeting. Eventually it becomes mighty close to being paranoid in some cases. It also connects directly to substance abuse, because those "feel good" chemicals aren't being produced by the brain.
From my understanding, the punches to the back of the head have the closest association with Parkinsons and Parkinson Syndrome, such as Ali had. There could be important genetic factors, as Ali's father had it, too. And Cosell had Parkinsons. Terrible disease. A good friend since grade school has it now, though he wasn't a fighter. Since doctors now recommend punching heavy bags, he asked me if I had a spare. I didn't have the right kind for his apartment, so my older boy bought him one.
An interesting story about Frazier later in life. He was pulled over for DWI, and at first attacked the officer. There are many scary things in life, but being attacked by Smokin' Joe had to be an intense experience.
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