Researchers have associated accumulated brain damage from years in the NFL with memory and cognition problems later in life, but researchers at Johns Hopkins have found the first evidence to directly link repeated brain injuries with memory problems decades later.
In a study published in Neurobiology of Disease, the researchers argue their findings involving nine former NFL players who were administered an assortment of cognitive and imaging tests support the need for better helmet protection in football.
“We’re hoping that our findings are going to further inform the game,” said Jennifer Coughlin, M.D., assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.
“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.”
While the link has been long suspected to exist, this is the first study to identify a potential mechanism causing these deficits.
In the study, the researchers recruited nine former NFL players between the ages of 57-74. The players spanned a variety of on-field positions and all had experienced a wide range of concussions, ranging from no history to 40 concussions in a single person. The researchers also found nine healthy age-matched control participants.
All participants in the study underwent positron emission tomography (PET) scans focused on the translocator protein, a marker for damage and repair efforts within the brain. Healthy individuals all showed low levels of the protein, but the former NFL players had concentrated areas with high levels of the proteins.
The healthy participants were also given magnetic resonance imaging (MRI) tests so the researchers would be able to match PET scan findings with anatomical locations in the brain. All participants were also given a variety of memory tests.
According to the PET scan findings, the former NFL players all showed evidence of brain injury in several temporal medial lobe regions, including the amygdala which helps regulate mood. Scans also found damage to many players’ supramarginal gyrus, which is associated with verbal memory.
MRIU scans also found evidence of atrophy on the right-side of the hippocampus in the former players, suggesting the region linked with memory may have shrunk due to previous damage. This would explain why the NFL players also scored low on memory testing, specifically on tests of verbal learning and memory.
The researchers admit the study is limited by its small size, but they argue the evidence is strong enough to suggest molecular and structural changes are happening in the brains of athletes with a history of repeated hits to the head well after they have retired.