Distinct brain features in football players may tell who is at risk of long-term traumatic disease

Brain scans from American football players reveal subtle differences in the brain’s outer grooves when compared to scans from otherwise healthy men who never played contact or collision sports, a new study shows. Its authors say the findings could potentially predict which people are more at risk of chronic traumatic encephalopathy (CTE).

Like many neurodegenerative diseases, CTE is known to worsen over time, and it afflicts many who play contact and collision sports that involve repeated hits to the head. Popular contact sports include soccer and basketball, while common collision sports are football, hockey, and boxing.

Despite years of research, clinicians must still rely on autopsies after death to diagnose CTE, often marked by shrinking of the brain and the presence of tau protein deposits in brain grooves (sulci) near blood vessels.

Led by an international team of researchers and NYU Langone Health, the study is part of a long-term effort to develop tests for early detection of CTE.

Researchers found that football players had shallower left superior frontal sulci on average than their nonfootball counterparts. The left superior frontal sulci are located on a main groove that runs along the top, front, left side of the brain, which is known from past studies to be physiologically affected in CTE. Researchers say sulci are very small and no more than 1.5 millimeters wide and 15 millimeters deep.

Published online in the journal Brain Communications, the study also showed that football players with increasing years of playing experience had wider left occipitotemporal sulci—a groove that runs along the left side of the brain—than men not involved in contact sports.

The study included an analysis of single MRI brain scans from 169 former college and professional football players. These scans were compared to those from 54 carefully matched males of similar age, weight, and education, who did not play football or similar sports, and who did not have active military backgrounds.

“Our study shows what we believe can be the first structural differences that tell apart brains more at risk of developing chronic traumatic encephalopathy from the brains of people who are less at risk,” said study senior investigator Hector Arciniega, Ph.D., an assistant professor in the Department of Rehabilitation Medicine at the NYU Grossman School of Medicine.

“The work also proves that we can apply what we know about the physical changes observed postmortem in the brains of those with confirmed chronic traumatic encephalopathy to brain scans of living people at increased risk for it.”

Arciniega, who is also a member of NYU Langone’s Concussion Center, says the findings could be adopted as early signs, or biomarkers, for CTE, advancing efforts to develop a diagnostic test, so that future therapies can be applied before the damage becomes irreversible. Because CTE has no cure, identifying and staging the severity of the risk is essential for strategies to prevent and treat the disease.

It is unclear why differences were detected only on one side of the brain and not in the sulci on both hemispheres, the researchers say. While differences in sulcal brain structure were shown, no differences were observed regarding comparison psychological tests for memory and learning, estimates of the number of head hits and injuries, and for other brain scan measures of tau protein buildup.

The researchers caution that a clinical diagnostic test remains years away. But they note that if future studies validate their findings, additional biomarkers could be combined, as part of many brain features, into a comprehensive CTE risk assessment.

Arciniega says his team has plans to expand its investigations to include more contact and collision sports. He also will test for differences in several other parts of the brain to help identify people most at risk of developing CTE.

Study volunteers were college football players who had at least six years of playing experience and professional football players with at least 12 years of gameplay. Their roles were linemen, receivers, and running and defensive backs. Quarterbacks were excluded because of their relatively low exposure to head trauma.