Football has become notorious for the degeneration it causes in players' brains. Now a preliminary study of soccer players has found that frequently hitting the ball with the head may adversely affect brain structure and cognition.
The study imaged the brains of 37 amateur soccer players, 21 to 44 years old, and found that players who reported “heading the ball” more frequently had microstructural changes in the white matter of their brains similar to those observed in patients with traumatic brain injury. These players also performed poorly on cognitive tests, compared with players who reported heading the ball less. The study, published online in June in Radiology, found evidence of a threshold—1,800 headings—above which the effects on memory begin to manifest. Neuroradiologist Michael Lipton of the Albert Einstein College of Medicine of Yeshiva University, who led the study, says the findings may indicate that heading causes mild concussions, even when players do not show symptoms.
The results are noteworthy but far from conclusive, comments Jonathan French, a neuropsychologist in the Sports Medicine Concussion Program at the University of Pittsburgh Medical Center, who was not involved in the study. “The majority of soccer players who are concussed don't have any functional problems in everyday life,” he says. The structural changes detected in the study, he points out, are "so microscopic that we don't know what they actually mean” for long-term function.
Lipton agrees more work is needed to determine the significance of the brain changes, but he hopes to call attention to the potential risk because soccer is the most popular sport in the world.