On Sunday the National Football League holds its championship game, Super Bowl XLIV. It will be the first Super Bowl since the league acknowledged the link between mild head trauma--often caused by the game's rough style of play--and long-term brain damage, and overhauled its policies toward concussions. As many football fans may have noticed, players this season were more likely to remain on the bench than return to the field after a blow to the head, thanks to new rules forbidding them from playing after showing significant signs of concussion.

That change has been a long time coming, writes Deborah Blum in an Op-Ed today in The New York Times. While brain injury in football players has seen a growing emphasis in recent years--both in the media and in Congress--strong evidence for the link has been around for more than 80 years. In the piece, Blum describes a paper published in The Journal of the American Medical Association on October 13, 1928. "This raises the question--at least for me--as to why we are announcing the athlete concussion-dementia link as a new, and still somewhat debatable, issue some 80 years later," she writes.

In that study, performed by Dr. Harrison Martland, chief medical examiner in Essex, NJ,

Martland did autopsies on more than 300 people who had died of head injuries, looking for patterns of brain damage. For his study of boxers, he talked a fight promoter into giving him a list of 23 former fighters he thought could be labeled as definitely punch drunk. Martland was able to track down only 10 of the former athletes, but in those cases, he found the promoter's diagnosis was on target. Four were in asylums, suffering from dementia. Two had difficulty forming sentences or responding to questions. One was almost blind, two had trouble walking and one had developed symptoms similar to those of Parkinson's disease.

More recently,

Surveys done in the last few years have found that N.F.L. players are at higher risk of dementias and other mental disorders than the general population. Autopsies of athletes -- notably the brains of former N.F.L. players who suffered from profound dementias -- consistently found dark clusters of nerve cell proteins, formations more common to elderly Alzheimer's patients. Similar patterns of damage were recently reported in wrestlers and soccer players. Most of these athletes were dead by age 50."

...At a Congressional hearing on football brain injuries, held in Houston on Monday, legislators accused college athletic officials of ignoring risks and failing to adopt polices that sufficiently protected young players. "It's money, money, money," said Representative Steve Cohen, a Tennessee Democrat, "and health care ought to be considered."

Researchers are working hard to develop better ways to study the problem, including helmets designed to detect concussions, which would alert players or coaches when they need to be benched, or even prevent them. And new ways to study mild traumatic brain injury, which doesn't show up in traditional brain scans.

In honor of Veterans Day,Technology Review is again highlighting some recent advances in understanding traumatic brain injury--a central issue for many of the troops returning from Iraq and Afghanistan. We first highlighted this problem in a feature in 2007, Brain Trauma in Iraq.

This year, David Moore, a neurologist highlighted in the feature, showed that diffusion tensor imaging, a brain imaging technology, could distinguish between blast-related injuries and other sources of concussion.

According to a recent story of ours:

The blasts caused by improvised explosive devices in Iraq and Afghanistan appear to inflict a fundamentally different type of brain damage than do more traditional sources of concussions, such as blunt trauma. The findings point toward new approaches to diagnosing and monitoring these injuries, which have been a huge concern to the military in recent years. The research also begins to resolve a controversy in brain-injury research--whether soldiers who are near an explosion but don't get hit in the head can still suffer a unique type of brain damage.

Regular concussions are typically caused by direct impact to the head, such as in a fall, or acceleration injuries, as in car accidents. In contrast, blast-induced brain injuries can include both of these factors as well as one that is unique to explosions--a rapid pressure wave that may wreak its own havoc on the brain. As a growing number of troops return from Iraq and Afghanistan with signs of brain injury--post-deployment surveys suggest that 10 to 20 percent of all deployed troops have experienced concussions--the military has been under increasing pressure to understand how this pressure wave affects the brain, as well as how best to diagnose and treat the resulting injuries.

Typically, damage from concussions does not show up on traditional medical imaging tests, such as CT scans or MRIs. But scientists have recently begun using a variation of MRI known as diffusion tensor imaging (DTI) to detect damage to the brain's white matter--the neural wiring that connects cells--after mild traumatic brain injury.

In the new study, David Moore, a neurologist and deputy director for research at the Defense and Veterans Brain Injury Center in Washington, D.C., and colleagues used DTI to assess troops who had been diagnosed with mild traumatic brain injury following a blast, a direct impact, or an acceleration-induced injury several months prior, as well as healthy people who had never suffered a concussion. They found that those with blast-linked trauma had a more diffuse pattern of damage to the white matter, described as a "pepper-spray pattern," than those whose concussions were caused by direct impact or acceleration. The research was presented at the World Congress for Brain Mapping and Image Guided Therapy conference in Boston last month.

Researchers are also pushing forward a blood test to assess more severe brain injuries. According to the piece,

One blood test already used in Europe to screen head-trauma patients before CT scans detects a protein called S100B, which is released by astrocyte cells in the brain after injury. "The thinking is, if you don't have [this marker] in the blood, then you don't have the kind of brain injury you could see on CAT scan," says Jeffrey Bazarian, an emergency-room physician and scientist at the University of Rochester Medical Center, in New York. The test is not approved for use in the United States, however. In a set of clinical guidelines for evaluating head trauma published recently, Bazarian and others estimated that the S100B test could significantly reduce unnecessary CT scanning. "We predict it could eliminate unnecessary radiation in a lot of people--about 30 percent [of those who come into the ER with brain injury]," he says.