I remember as a boy sitting in front of our black and white TV set watching Red Skelton slip into the persona of Cauliflower McPugg, the boxing ring "has been." Dodging and weaving to avoid the imaginary fists flying in the air, Skelton as McPugg staggered and mugged for the camera. I laughed myself silly. Unfortunately this was a time in our culture when tragedies such as dementia, drunk driving and spousal abuse were simply not part of our social consciousness.
In fact, a well-known cause of dementia is dementia pugilistica, or what has commonly been called being "punch drunk." This is a decline in cognitive function that occurs after repeated head injuries such as prizefighters receive fighting year after year in the boxing ring. The more head punches a fighter receives, the more likely he is to suffer the disorder. In some cases, the presentation of dementia pugilistica is virtually indistinguishable from Alzheimer's dementia. Differences can be noted in the history that led up to the decline in function. Moreover, while neurofibrillary tangles are always present at autopsy in dementia pugilistica, the amyloid plaques that are so prominent in Alzheimer's dementia may not appear until late in the progression of the illness.
The appearance of neurofibrillary tangles may be the first abnormality that appears in the brains of individuals that suffer repeated head injuries. These tangles of tau protein are frequently seen in retarded individuals with the terrible behavior of head banging, and may even be seen in young football players if they have had more than their share of bad bangs to the head during play. Soccer players can exhibit some of the same changes in brain tissue and cognitive function. It may be a comfort for some to know that this doesn't occur from simply "heading" the ball on repeated occasions, but rather from genuine head injuries sustained during games. This might occur when two players attempt to head the ball, but head each other instead. Another well-known effect of repeated head injury is increased risk for Parkinson's disease. This is likely the cause of the symptoms of Parkinson's disease that the great heavyweight boxer, Muhammad Ali, is now suffering, although it is hard to believe that he was hit enough times to have been placed at risk.
A frightening numbers of Traumatic Brain Injuries (TBIs), have been sustained by our young soldiers in the Iraq War. Unfortunately, there is growing evidence that TBI is a risk factor for early onset of dementia similar to Alzheimer's dementia. It is now suspected that the so-called "shock wave" of the explosion does not have to force objects against the head, or even directly reach the head itself for brain injury to occur. The very high pressures and velocities of the shock waves can apparently injure the brain indirectly by forcing waves of pulsations through the arteries into brain tissue. There is even speculation that such explosions can produce electromagnetic radiation that can injure the brain, particularly brains in heads covered by Kevlar helmets rather than the steel helmets used in previous wars. This type of damage can manifest on the microscopic level, and is thus very difficult to detect by standard methods such as CT scans or MRIs. The Department of Defense is investing a great deal of money into investigating various ways in which explosions injure the brain, how this damage can be avoided or, at least, quickly diagnosed and treated when it does occur.
I feel obligated to add that head injury does not entail subsequent development of dementia. One of my favorite and most interesting patients, a woman who is now in her 80s, had about 30 years prior to coming to see me suffered a catastrophic head injury in a motor vehicle accident. She barely survived her injuries. She had lost the ability to walk, talk, read, and write, and she slowly and laboriously had to relearn the most basic activities of daily living. The injuries she sustained were severe, and certain areas of her brain were simply destroyed. This is likely the reason that she is still unable to do many of the things she could do prior to the accident. Although she was a gifted classical pianist, she lost and never recovered her ability to play the piano. In fact, she still struggles to even make sense of music to which she listens. She carries a persistent feeling that she has no self, which is particularly tragic when she shows such warmth and humor in her interactions with me. Nonetheless, while some areas of her brain are damaged beyond repair, she exhibits absolutely no indications of any progressive, neuro-degenerative processes having been initiated by that trauma to her brain tissue. She reads and loves to discuss with me the latest books on economics and political science. Her memory is probably better than mine. She drives, manages her finances, and cares for herself perfectly well in the home where she lives on her own. Why it is that some people begin to exhibit neuro-degenerative changes after a few hard hits in football, whereas others show no such damage even after the very substance of the brain is ripped and shattered is entirely unknown.