Frequent soccer ball heading may lead to brain injury

Soccer players who head the ball a lot demonstrate poorer performance on memory tests and have brain abnormalities similar to those found in traumatic brain injury patients, U.S. researchers reported Tuesday. "We studied soccer players because soccer is the world's most popular sport," said Michael Lipton, associate director of the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine and the study's lead author, in a statement. "Soccer is widely played by people of all ages and there is concern that heading the ball -- a key component of the sport -- might damage the brain," said Lipton. The study, published online in the journal Radiology, found that soccer players head the ball, on average, six to 12 times during games, where balls can travel at speeds of more than 50 miles (80 kilometers) per hour, and during practice sessions, players commonly head the ball 30 or more times. The impact from a single heading is unlikely to cause traumatic brain damage such as laceration of nerve fibers, but repetitive heading could set off a cascade of responses that leads to degeneration of brain cells over time, said Lipton. To study possible brain injury from heading, the researchers used an imaging technique called diffusion tensor imaging (DTI) on 37 amateur adult soccer players with a median age of 31, who had all played the sport since childhood. The participants reported playing soccer for an average of 22 years and had played an average of 10 months over the previous year. The DTI allows researchers to assess microscopic changes in the brain's white matter, which is composed of billions of nerve fibers called axons that act like communication cables connecting various regions of the brain. The imaging technique produces a measurement, called fractional anisotropy (FA), which characterizes the movement of water molecules along axons. Abnormally low FA within white matter indicates axon damage and has previously been associated with cognitive impairment in patients with traumatic brain injury. "The DTI findings pertaining to the most frequent headers in our study showed white-matter abnormalities similar to what we've seen in patients with concussion," said Lipton. "Soccer players who headed the ball above a threshold between 885 to 1,550 times a year had significantly lower FA in three areas of the temporal- occipital white matter." Players with more than 1,800 headings per year were also more likely to demonstrate poorer memory scores compared to participants with fewer yearly headings, Lipton said. "Our study provides compelling preliminary evidence that brain changes resembling mild traumatic brain injury are associated with frequently heading a soccer ball over many years," said Lipton. " While further research is clearly needed, our findings suggest that controlling the amount of heading that people do may help prevent brain injury that frequent heading appears to cause."