We’ve discussed concussions on this site many times before (just put concussion in the search bar). The actual mechanism of concussion and how it adversely affects the brain is still relatively unknown.
Marchi et al, 2013 tested the integrity of the blood brain barrier in American football players’ pre and post-game to determine what, if any, changes could be determined. We know that blood brain barrier disruptions are implicated in Alzheimer’s, stroke and multiple sclerosis. One of the primary problems when the barrier is disrupted is the nervous system encounters proteins it has never seen before and literally creates anti-bodies to proteins in your own brain.
Blood was drawn pre game, 1 hour post-game and 24 hours post-game. The blood was tested for S100B, a protein found in astrocytes and for S100AB, the anti-body the body generates when it leaks out of the brain and into the body. Head impact was monitored by video replay and athletes completed a questionnaire about the effects the impact had on their short and long term abilities. Computer cognitive testing was also used to determine any immediate changes in brain behavior and processing.
They showed that even sub-threshold hits resulted in elevation of S100B and S100AB. This is not conclusive evidence that the brain blood barrier is critical in concussion but it demonstrates that the central nervous system can be attacked by the immune system after even minor head impacts. Given the auto-immune considerations in many central nervous conditions- head impacts now become a major concern.
We know from studies in soccer that many sub-threshold hits can accumulate and lead to long-term cognitive deficit. This is another nugget of evidence that head trauma is a major problem. At some point we are going to have a side line saliva test for this but until then, take care of your brain.