A new study has found that soccer players who frequently hit the ball with their heads have brain abnormalities resembling those found in patients with concussions.
For the study, researchers at Albert Einstein College of Medicine of Yeshiva University used advanced imaging techniques and cognitive tests that assessed memory.
“We studied soccer players because soccer is the world’s most popular sport,” said Michael Lipton, M.D., Ph.D., associate professor of radiology, psychiatry and behavioral sciences and director of Einstein’s Gruss Magnetic Resonance Research Center.
“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.”
Soccer players head the ball an average of six to 12 times during games, where the balls can travel at speeds of more than 50 miles per hour. During practice, players commonly head the ball 30 or more times, according to the researcher.
While the impact from a single heading is unlikely to cause traumatic brain damage, such as laceration of nerve fibers, cumulative damage from repeated impacts “could set off a cascade of responses that leads to degeneration of brain cells over time,” noted Lipton.
To study possible brain injury from heading, the researchers used diffusion tensor imaging (DTI), an advanced MRI-based imaging technique, on 37 amateur adult soccer players.
The participants, who had a median age of 31, reported playing soccer for an average of 22 years and had played an average of 10 months over the previous year.
The researchers ranked the players based on heading frequency and then compared the DTI brain images of the most frequent headers with those of the remaining players. All participants also underwent cognitive testing.
According to the researchers, DTI “sees” the movement of water molecules within and along axons, the nerve fibers that constitute the brain’s white matter. This imaging technique allows researchers to measure the uniformity of water movement — called fractional anisotropy (FA) — throughout the brain.
Abnormally low FA within white matter indicates axon damage and has previously been associated with cognitive impairment in patients with traumatic brain injury, the researchers explained.
“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.”
Lipton added that players with more than 1,800 headings a year were also more likely to demonstrate poorer memory scores.
“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,” he said.
“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.”
The study was published online in the journal Radiology.