“Heading” a Soccer Ball Could Lead to Brain Injury
Heading, in which players field the soccer ball with their head, is an essential part of the game and the focus of many training drills.
"Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain," said Michael L. Lipton, MD, PhD, associate director of the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine and medical director of MRI services at Montefiore Medical Center in New York. "But repetitive heading could set off a cascade of responses that can lead to degeneration of brain cells."
Using diffusion tensor imaging (DTI) to study the effects of soccer 'heading,' researchers have found that players who head the ball with high frequency have brain abnormalities similar to those found in traumatic brain injury (TBI) patients.
DTI, an advanced magnetic resonance (MR) technique, allows researchers to assess microscopic changes in the brain's white matter, which is composed of millions of nerve fibers called axons that act like communication cables connecting various regions of the brain.
DTI produces a measurement, called fractional anisotropy (FA), of the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform and measures high in FA. When water movement is more random, FA values decrease.
The five regions identified by the researchers are responsible for attention, memory, executive functioning and higher-order visual functions. The analysis revealed a threshold level of approximately 1,000 to 1,500 heads per year. Once players in the study surpassed that level, researchers observed a significant decline in their FA in the five identified brain regions.
"What we've shown here is compelling evidence that there are brain changes that look like traumatic brain injury as a result of heading a soccer ball with high frequency," Dr. Lipton said. "Given that soccer is the most popular sport worldwide and is played extensively by children, these are findings that should be taken into consideration in order to protect soccer players."
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