MRI Detects Brain Injuries Caused by Heading Soccer Balls

June 11, 2013

Diffusion tensor imaging demonstrates changes in the brain of soccer players who head the ball frequently during games and practice.

MR images show brain abnormalities in soccer players who frequently head the ball, according to a study published in the journal Radiology.

Soccer players head the ball, on average, six to 12 times during competitive games and heading is often practiced repeatedly during practice sessions. Because of the velocity of the ball as it approaches the player, the impact with the head can be substantial.

Researchers from New York and California sought to investigate the association of soccer with subclinical evidence of traumatic brain injury (TBI). They recruited 28 male and nine female amateur soccer players who completed a questionnaire and cognitive function testing, and underwent diffusion tensor imaging (DTI), an advanced MR imaging technique. The players’ median age was 31 and they had reported playing soccer for an average of 22 years.

“Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain,” lead author Michael L. Lipton, MD, PhD, said in a release. “But repetitive heading could set off a cascade of responses that can lead to degeneration of brain cells over time.” Lipton is the associate director of the Gruss Magnetic Resonance Center at the Albert Einstein College of Medicine and the medical director MRI at Montefiore Medical Center in New York City.

DTI produces fractional anisotrophy (FA), which characterizes the movement of water molecules along axons. The researchers were looking for microscopic changes in the brain’s white matter. Water movement is generally uniform and measures high in FA, however when water movement is more random, FA values are lower, something that has been associated with cognitive impairment in patients with TBI.

The researchers found that over the previous year, the players had headed the ball a reported 32 to 5,400 times, with a median of 432. The heading was associated with lower FA at three locations in temporo-occipital white matter with a threshold that varied according to location. The more the players headed the ball, the lower the FA values.

Results also showed that lower levels of FA were also associated with poorer memory scores, with a threshold of 1,800 headings per year. However, lifetime concussion history and demographic features were not significantly associated with either FA level or cognitive performance.

“The brain findings of the most frequent headers in our study showed abnormalities of white matter similar to what we’ve seen in patients with concussion,” Lipton said. “Soccer players who headed the ball above a threshold of 885 to 1,550 times a year had a significantly lower FA in three areas of the temporal-occipital white matter.”

The authors concluded that more research should be a priority and that measures should be taken to control the amount of soccer ball heading.