Repetitive soccer ball 'heading' could lead to brain injury

In the past decade, concern has been raised surrounding concussions and mild traumatic brain injuries sustained by football players and military personnel, as more and more studies have indicated that these injuries may have a lasting impact on cognition and memory. And now, another kind of athlete could potentially be at risk for similar types of brain abnormalities: Soccer players.

Utilizing advanced magnetic resonance imaging (MRI) techniques, researchers from the Albert Einstein College of Medicine in New York City found that numerous repetitions of the soccer move known as ‘heading,’ are associated with adverse brain changes comparable to those found in patients with traumatic brain injury (TBI).

“What’s unique about this study is this is the first study ever to quantify heading as an exposure,” Dr. Michael Lipton, associate director of the Gruss Magnetic Resonance Research Center at Albert Einstein College of Medicine, told  “…We’re actually quantifying the amount of heading people did as a predictor of both changes in the brain and both changes in function.”

Heading refers to a popular soccer move in which players direct the soccer ball with the tops of their heads.  According to Lipton, active soccer players will head the ball an average of five to six times during a competitive match.  But the real bulk of soccer heading happens during practice sessions, in which a player could repeatedly head the ball up to 30 times or more.

“Specifically soccer heading entails numerous repetitions of mild impact to the head,” said Lipton, who is also the medical director of MRI at Montefiore Medical Center in New York City. “My area is mild traumatic brain injury, so I look at how much does it take (to have a lasting effect).  Soccer players are repeatedly hitting their head, and we know that multiple head injuries tend to be worse than just one.”

To better understand the potential impact repetitive soccer heading has on the brain, Lipton and his team conducted diffusion tensor imaging (DTI), an advanced MRI technique that allows researchers to analyze microscopic changes in the brain’s white matter.  Composed of billions of nerve fibers called axons, white matter is responsible for transmitting signals to and from various regions of the brain.

DTI helps to measure the movement of water molecules along the axons in white matter – calculating a value known as fractional anisotropy (FA).  When white matter is healthy and functioning properly, this water movement is consistent and produces high measures of FA.  But when the movement of water is abnormal, FA values decrease.  Low FA levels have been associated with impaired cognition in patients with TBI.

The researchers utilized 37 amateur soccer players with a median age of 31 for the study.  Twenty-nine of the participants were men, and all had reported playing soccer for an average of 22 years, having played an average of 10 months within the past year.

Through various interviews and structural assessments, Lipton and his team estimated the amount of heading the players had done on an annual basis before imaging their brains.  After the DTI was performed, the participants underwent a series of cognitive tests to measure memory and brain function.

Overall, the imaging showed that players who reported heading the ball more frequently had areas of the brain with lower FA values.

“The more heading people did, the more likely they were to have abnormalities of brain microstructure and worse cognitive performance,” Lipton said.  “However, it’s not a relationship where the more they did the worse it was; but when they crossed a threshold level, we started to see a change in the brain measure typical in brain injury.”

According to Lipton, players who headed the ball above a threshold of 885 to 1,550 times a year had significantly lower FA in three areas of the temporal-occipital white matter. Furthermore, the players who had at least 1,800 heads a year were much more likely to score poorly on the memory tests.

Helmets are currently not required by major soccer organizations, but many have debated the need for protective headgear, and companies such as Full90 have developed lines of soccer head guards for those looking for extra protection.  However, while many within the soccer community feel these products are unnecessary, soccer organizations are not opposed to change.

“Now if there’s new data, we analyze it, and we want to make sure in our organization our players are safe,” Robert Martella, the director of operations for U.S. Youth Soccer, the largest largest member of the United States Soccer Federation, told  “That’s our biggest function for us… We have some very well versed physicians in our soccer community.”

Martella said that when new studies are released, their organization reviews the findings with U.S. Soccer and their medical board to determine if there should be any changes in policy – or even technique.

“When the new information comes out and once our group has time to break down the data, our coaching department plays a key role in that, because they’re teaching the coaches the proper technique and communicating that through coaching courses,” Martella said.

Lipton said the findings do not necessarily mean that crossing this heading threshold means something bad will happen to a soccer player’s brain, but the results do present compelling evidence that changes in the brain do occur in association with high frequency of soccer ball headings.  He said his team is still in the middle of conducting a long term prospective study of soccer players and ball headings, analyzing their brains before and after years of playing soccer.

“I think that what people should take away from this at this point is that there may be risk involved in heading; that’s about all we can say at this point,” Lipton said.  “…There are people who advocate banning heading in youth soccer and there are other people who are adamant there can be nothing wrong with this.   The biggest message here is we need to do the research and confirm what the risks are, and if they’re confirmed, develop ways to address them.”

The research is published online in the journal Radiology.