BEER-SHEVA, Israel – Despite protective equipment and regulations designed to keep professional athletes safe, their brains still take quite a beating. While an occasional blow to the head might not be a huge concern, repeated impacts are common in sports like football, hockey, and boxing. Concussions, of course, are linked to chronic traumatic encephalopathy (CTE), a chronic and progressive brain disease. The only way to diagnose CTE is by examining someone’s brain after they’ve died. However, a new brain imaging technique developed by scientists at Ben-Gurion University in Israel may provide a way to diagnose CTE in professional athletes while they’re still alive.
A primary characteristic of CTE is disruption of the brain’s blood brain barrier (BBB). This barrier is a layer of cells that prevents harmful substances, such as toxins and bacteria, from entering the brain. In CTE, the barrier becomes “leaky,” meaning that it no longer filters out harmful substances the way it should. A leaky BBB has been linked to a number of diseases including Alzheimer’s disease, depression, dementia, and schizophrenia.
Scanning for leaky BBB among athletes
In the study, researchers developed a modified brain imaging technique known as dynamic contrast-enhanced-MRI (DCE-MRI), which can measure BBB permeability. They then compared barrier permeability across two different groups of people. The first group consisted of 42 athletes who play in the American-style Israeli Football League (IFL). The second group included 27 athletes who play a non-contact sport, and 26 non-athletes.
Researchers say that football players are three times more likely to have BBB disruption compared to athletes who play a non-contact sport and non-athletes. They also reveal that a leaky BBB is specific to particular parts of the brain (including white matter, midbrain peduncles, red nucleus, and temporal cortex).
Further, they show that BBB disruption is present in players both during football season and during the offseason. This suggests that the condition is persistent.
Link to CTE could open door to concrete testing
The individuals included in the study did not have any obvious symptoms or signs of CTE. But researchers say it’s likely that a leaky BBB occurs before symptoms are apparent. Future studies will be necessary to directly examine how blood brain barrier permeability is related to clinical symptoms of CTE.
“Since a leaky BBB is also found in CTE and causes brain dysfunction and degeneration, it now seems that this test could provide the first (and so far the only) evidence for brain injury in the players we studied on the Israel football team,” says Prof. Alon Friedman, M.D., a neurosurgeon and researcher at BGU and Dalhousie University in Canada, in a statement.
Researchers also suggest that combining brain imaging techniques with symptom questionnaires will likely be the best way to determine whether athletes are healthy enough to keep playing.
“Not less important is the observation that few players who did not complain of severe symptoms also showed a leaky BBB. This suggests that DCE-MRI should be used in conjunction with symptom questionnaires before return to play is approved,” concludes Dr. Friedman.
The study is published in Brain.