Chuck Bednar for redOrbit.com – Your Universe Online
A study of nine former National Football League players has found that concussions suffered during their careers may be responsible for memory loss and mood issues experienced decades after they retired.
Writing in the February 2015 edition of the journal Neurobiology of Disease, experts from the Johns Hopkins University School of Medicine report that they conducted a battery of imaging and cognitive tests to gather evidence that accumulated brain damage could be linked to issues being experienced by former NFL stars long after they hung up their jerseys.
The study authors hope that the results of the small-scale study of nine ex-NFL players provide additional evidence that sustaining repeated concussions can have long-term neurological impact on these athletes. The findings also support the call for better player protection, they added.
“We’re hoping that our findings are going to further inform the game,” said study author Dr. Jennifer Coughlin, an assistant professor of psychiatry and behavioral sciences at the university. “That may mean individuals are able to make more educated decisions about whether they’re susceptible to brain injury, advise how helmets are structured or inform guidelines for the game to better protect players.”
There have been several anecdotal accounts and scientific studies linking permanent brain damage to repeated concussions suffered by football players and other athletes, the authors said. Last fall, the NFL acknowledged that at least one-fourth of players are likely to suffer from cognitive impairments after their careers are over, and several companies have been working on smart helmets and other types of equipment designed to make the game safer.
Despite the awareness of the problem, however, the damage mechanisms and the exact sources of these issues have remained unclear. In order to shed some light on them, Coughlin and her colleagues used put the former players through a battery of tests designed to directly detect brain deficits and to quantify localized molecular differences between their brains and those of healthy people who did not play football.
The players involved in the study had been retired for several decades, and ranged in age from 57 to 74. They had played a variety of different positions and had experienced an array of historical, self-reported concussions, ranging from none for a running back to 40 for a defensive tackle. The authors also recruited nine age-matched control subjects deemed unlikely to have experienced brain trauma.
“Each of the volunteers underwent a positron emission tomography (PET) scan, a test in which an injected radioactive chemical binds to a specific biological molecule, allowing researchers to physically see and measure its presence throughout the body,” the university explained.
“In this case, the research team focused on the translocator protein, which signals the degree of damage and repair in the brain,” they added. “While healthy individuals have low levels of this protein spread throughout the brain, those with brain injuries tend to have concentrated zones with high levels of translocator protein wherever an injury has occurred.”
In addition, the volunteers underwent MRIs, which allowed Coughlin’s team to match the findings of the PET scan with anatomical locations in their brains and to check for structural abnormalities. Each participant was also asked to undergo a series of memory tests.
There was no evidence of brain damage in the control volunteers tests, but the PET scan showed that, on average, the former NFL players had evidence of injury in several temporal medial lobe regions, including the amygdala, which plays a significant role in regulating mood. Those scans also identified damage to many players’ supramarginal gyrus, which is linked to verbal memory.
The PET scans did not reveal evidence of damage in the former players’ hippocampus, an area that plays a role in several aspects of memory, the MRIs revealed some atrophy in the right-side hippocampus, suggesting that the region may have shrunk in size due to previous damage. Also, many ex-players scored low on tests of their verbal learning and memory function.
While the authors emphasize that their pilot study is small in size, they state that the findings indicate that there are molecular and structural changes in specific brain regions of athletes with histories of repetitive hits to the head, even many years after they stepped away from the game.
Currently, the researchers are looking for translocator protein hotspots in both active and recently retired NFL players to help determine if these changes are present shortly after the time of play, or if they only develop over the course of time as a delayed response to injury. They also believe that the molecular brain imaging technique could be used to change the way that football players and other athletes are treated after experiencing a possible concussion.
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