Could Frequent Soccer Headers Result in Brain Injury?

Though soccer moms often juggle hectic schedules between checking homework, prepping food for the kids, and carpooling kids to games, they should also make time to be aware of the risk for brain injuries.
Researchers are continuing to look into the impact of frequent headers - which refers to when soccer players deliberately hit or field the soccer ball with their head - on the brain, even without concussions.
A new study of a small group of professional soccer players, who had trained since childhood, published in the Nov. 14 issue of the Journal of the American Medical Association, suggested that frequent headers that did not cause a concussion may still result in changes to the brain’s white matter.
The white matter of the brain contains many nerve fibers. And it is surrounded by a fat called myelin that acts as an insulator and increases the speed of transmission of nerve signals. The myelin gives it the whitish appearance. In comparison to the gray matter, it has been the “long-neglected half of the brain,” according to the Dana Foundation, a New York-based foundation that supports brain research.
“On average, elite male soccer players -- who often use their heads to direct the ball -- had a range of negative changes in white matter architecture compared with a group of competitive swimmers who were unlikely to have repetitive brain trauma,” according to Inga Koerte, MD, of Harvard Medical Schools Psychiatry Neuroimaging Laboratory in Boston, and colleagues, in MedPage Today.
Those differences were observed even though none of the participants in either group had a history of concussion, Koerte and colleagues reported in a research letter in JAMA. Although it is possible that frequent heading of the ball could explain the impairments in the soccer players, "differences in head injury rates, sudden accelerations, or even lifestyle could contribute," the authors wrote.
Two previous brain imaging studies presented last November at the annual meeting of the Radiological Society of North America (RSNA) in Chicago have shown risk for brain injury and cognitive impairment.
Researchers at Albert Einstein College of Medicine of Yeshiva University, a research-intensive medical school based in the Bronx, New York, and Montefiore Medical Center, the University Hospital and academic medical center for Einstein, conducted these studies. They used diffusion tensor imaging, an advanced MRI-based imaging technique, on 38 amateur soccer players, who had played the sport since childhood. While analyzing brain images of the most frequent headers during the past year, they found brain injury similar to that seen in patients with concussion, also known as mild traumatic brain injury.
“Our goal was to determine if there is a threshold level for heading frequency that, when surpassed, resulted in detectable brain injury,” said lead author Michael Lipton, M.D., Ph.D., associate director of Einstein’s Gruss Magnetic Resonance Research Center, medical director of MRI services at Montefiore.
Researchers found a threshold level of approximately 1,000 to 1,500 heads per year. Beyond that number of headers, they observed significant injury. “Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain,” said Dr. Lipton in the media release. “But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells.”
Another study with the same set of 38 amateur soccer players examined neuropsychological function through tests of verbal memory and activities with mind-body coordination such as throwing a ball. The study found that players with the highest annual heading frequency performed worst on these tests.
“These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency,” Dr. Lipton said. “These are findings that should be taken into consideration in planning future research to develop approaches to protect soccer players.”
Since soccer rules prohibit players from using their hands or arms to direct the ball except for the goal keeper, it doesn’t appear that the practice of heading the ball will be eliminated anytime soon, but additional research may help establish guidelines to limit the practice to a certain threshold of safety.