Friday, January 19, 2007

The dynamics of concussion

As I was driving home last night I happened to listen to a program on NPR that talked about the suicide of former National Football League player Andre Waters (he killed himself in November of last year). After examining remains of the player’s brain, a neuropathologist in Pittsburgh is claiming that Mr. Waters sustained brain damage from concussion related injuries while playing football and says that these injuries lead to depression and ultimate death.

Dr. Bennet Omalu (the neuropathologist on the case) of the University of Pittsburgh, has determined that Mr. Waters’s brain tissue degenerated into a brain that had characteristics of an 85-year-old man with early-stage Alzheimer’s disease. A lot of credit should be given to Mr. Chris Nowinski, a former Harvard football player and professional wrestler whose repeated concussions ended his career. These injuries also left him with severe migraines and depression. It also pushed him into exposing the dangers behind concussions to the brain tissue suffered from contact sports that often go unattended because in most cases the player just runs back into the field in response to cheers of heroism.

All of this got me thinking a bit more about the exact neurology behind concussion.. I would be interested in the exact neurobiology behind brain concussion, could not find too much on the web, but here is a little theory behind the sequence of events that might occur:

Our brain is suspended within our skull in a fluid medium called the cerebrospinal fluid (in fact our brain actually floats in this fluid and would our brains would limply lie on its sides without this support from the cerebrospinal fluid and the surrounding skull to give it shape and support). A concussion is trauma suffered to brain tissue usually as a result of a very sharp blow to some part of the skull that could cause temporary cognitive deficits. Sharp blows essentially translate to forces on our brain that propel the brain-mass to impact the inside of our skulls with very high velocities. High velocity brain matter can’t really go anywhere; it is abruptly stopped in its tracks by the inner surface of our skulls. In being stopped, very high impact forces are transferred from the hard dura that covers the inner surface of our skulls to the cerebral surface of the brain tissue. Sudden buildup of pressure in a localized area of the brain translates to even higher pressures inside the miniature capillaries that snake and find their way through the cerebral tissue. As brain tissue (neurons and glia) squeezes on the capillary, the blood really has no place to go but rupture the capillary and flow out in multiple minute locations (all of this might be happening at the level of minutest capillary – but nonetheless is a possibility). Of course, the sum effects of this are so small that normally nothing really happens. But repeated injuries taking place over a period of time (say over a players career), could lead to multiple blood vessel ruptures in various areas of the brain (doctors tend to call these vascular infarcts). Over time, decreased blood supplies (albeit in small quantities) and microscopic ruptures compromise the individual cells that make up our brain – the neurons. In fact necrotizing tissue could also be formed in small pockets all over the brain from the minute ruptures. Large scale cognitive deficits start to show on the individual’s personality as multiple areas involved in sensory processing and higher order executive functions start to function at decreased processing power. Some of this could be manifested as depression, migraines, headaches, listlessness etc. Maybe this is what killed Mr. Waters - we will never know for sure, but the time has come for us to look closely at the business of sending our kids off to play football or other contact sports.

I am not saying that contact sports is a bad thing, but better research needs to be dedicated to protecting the soft matter that we implicate for the development of our 'selves' within our heads.

Some of the research that I managed to dig up in this regard is here:

Traumatic brain injury and concussion in sports - James P. Kelly MD JAMA Sept 8 1999 Volume 282 No 10 Page 989

The nature of concussion: a speculative hypothesis - Paul McCrory (Br. J. Sports Med. 2001;35;146-147)

Attentional deficits in concussion - P. VAN DONKELAAR, J. LANGAN, E. RODRIGUEZ, A. DREW, C. HALTERMAN, L. R. OSTERNIG, & L.-S. CHOU Department of Human Physiology and Institute of Neuroscience, University of Oregon, Eugene, OR, USA

Essential Information for Athletes, Parents, and Coaches


Anonymous said...

Even as the NFL changes rules and helmet makers improve their designs, the league says concussion rates have stayed level at about 0.4 incidents per game in recent seasons -- about 100 per year. But teams report only half of these. In the four seasons between 2000 and 2003, clubs listed a total of 203 concussions on weekly injury reports, according to data compiled by the Pittsburgh Tribune-Review. Not all teams suffer equally. Some clubs reported multiple head injuries in each of the years. The Colts listed 20 concussions.

The Patriots listed zero.

And a small-town New England dentist, who literally has been inside Patriots players' heads for 25 years, says he knows why.

Karl Zipser said...

Imagine what it must have been like in the middle ages with the knights with metal helmets on horses charging at each other. I wonder how many important historical figures had some kind of combat-related brain damage.

Sunil said...

Thanks for coming over. Yes, it must have been pretty bad. Just putting on all that jousting and battle armor could certainly give you a headache - not to mention fignting and doign head butts with it...