Repeated trauma to the brain is seen in football in every game. Two sides square off and slam into each other, sometimes with the force seen in explosions on the battlefield. For years there have been reports that the brain injuries that players sustain on the field may lead to permanent memory loss and loss of cognitive function.

Researchers have made two key assertions with new findings. Firstly, they can now test for brain damage by performing a simple, quick and cheap blood test. Researchers found that there was a detectable level of a protein that has been shown to be a biomarker in traumatic brain injuries, S100B. They saw that in 67 football players that didn't have a concussion, there was presence of this protein in players' blood after a game.

This shows that even routine hits, those that aren't severe enough to cause a concussion, can damage the blood brain barrier, which is important in protecting the brain from infection and other damage.

Secondly the researchers deduced that this S100B protein, which is normally not present outside of the brain, may cause an immune reaction when there is damage to the blood brain barrier and it leaks out into the rest of the body. Antibodies made by the immune system to attack this foreign protein could gain access to the brain through the damaged and leaky blood brain barrier and attack the protein and cause collateral damage to the brain tissue.

These multiple traumatic hits could allow the immune system to gain access to the brain and accidentally attack it.

Researchers showed that the more hits a player sustained in a game, the higher their blood levels of the S100B levels were in the blood. Researchers then predicted which players would have more brain damage and results were confirmed by MRI imaging tests of players brains.

"Although many scientists are actively investigating concussions in the United States right now, it's been difficult to study the link between brain injury, blood-brain barrier damage, and the long-term risk of neuro-degeneration because of a lack of simple, non-invasive tools," Dr. Bazarian, lead researcher on the project said.

The paper published in the journal PLos One can be found here.