Fran Lowry

November 29, 2011

November 29, 2011 (Chicago, Illinois) — Heading the ball in soccer is an integral part of the game, but it might also be a cause of brain injury, according to research presented here at the Radiological Society of North America 97th Scientific Assembly and Annual Meeting.

In a study of amateur soccer players, those who fielded the ball more frequently with their head had brain abnormalities similar to those seen in patients with traumatic brain injury. They also had evidence of impaired cognition, said Michael Lipton, MD, PhD, associate director of the Gruss Magnetic Resonance Research Center at the Albert Einstein College of Medicine in New York City.

Dr. Michael Lipton

Heading the ball during a game is common, but it is even more common during practice sessions. "Players do these drills where they literally beat the ball back and forth between a coach throwing it at a player, or 2 players using their heads. They'll do this 30, 40, or more times at a shot. People who are playing pretty intensely, who spend at least 3 days a week in some pretty intense soccer play, can report an excess of 5000 heads a year," Dr. Lipton told Medscape Medical News.

Dr. Lipton and his team used diffusion tensor imaging to detect changes in brain white matter, as indicated by fractional anisotropy, in 32 amateur soccer players. They also estimated how often each player headed the ball on an annual basis, and then ranked the players according to heading frequency.

The average age of the players was 31 years, and all had played soccer since childhood.

"Lower fractional anisotropy is an indication of derangement of brain structure at a microscopic level," Dr. Lipton explained. "In normal white matter, the diffusion or movement of water molecules is highly organized and collinear, but in the presence of any kind of injury, some of the structure that essentially shepherds those water molecules all in the same direction is lost, and the movement of water molecules becomes more random."

This derangement is seen in traumatic brain injury and is associated with cognitive impairment in patients with traumatic brain injury, he added.

The investigators compared the brain images of the players who had a heading frequency of 1320 per year or more with players who had a heading frequency of less than 1320 per year.

They found that greater heading frequency was associated with low fractional anisotropy. Players with higher heading frequency had significantly lower fractional anisotropy in 5 brain regions in the frontal lobe and in the temporo occipital region, compared with those with lower heading frequency.

"These 5 regions are responsible for attention, memory, executive functioning, and higher-order visual functions," Dr. Lipton said.

The study also found that there was a threshold for the amount of heading required to cause these types of changes. When that threshold level was surpassed, white matter injury became detectable.

"Our analysis showed that approximately 1000 to 5000 heads per year was the threshold. Once players went past that, we observed a significant decline in their fractional anisotropy in the 5 identified brain regions," Dr. Lipton explained.

"The implication is that there is likely to be some safe range within which you can play soccer and head the ball and not have a bad effect from it. We don't know exactly where that threshold lies. More research needs to be done. Until then, caution is always a good thing, and that is generally what I tell people," he said.

The investigators also administered a battery of neuropsychologic tests, and found that those with the highest heading frequency had significantly poorer performance on tests of delayed verbal memory (P < .01) and visual motor function (P < .03), compared with those with lower heading frequency.

Dr. Lipton pointed out that this study looked at the effects of soccer heading in adults, but that children are likely to be even more affected.

"There are a lot of reasons to be concerned that this effect would be magnified in children," he said. "It would be very hard to attribute the ill effects of heading directly to that activity, because the types of problems that people will have as a result of the kind of injury we are talking about are very nonspecific. It would be very hard to know whether poor performance in school is due to heading. Research needs to be done to define what these effects are and to determine a safe threshold for heading."

Dr. Lipton added that he has no illusions that people will stop playing soccer.

"That's just not going to happen, but...we can definitely identify safe parameters within which the game can be played. I hope our study raises awareness. The solution doesn't have to be proscriptive, it just has to identify safe parameters within which we can play safely."

Commenting on this study for Medscape Medical News, Max Wintermark, MD, chief of neuroradiology at the University of Virginia in Charlottesville, said: "These data are interesting, and the fact that neurocognitive findings support the imaging findings reinforces the validity of the study. However, the study sample is small, and these findings need to be confirmed in a larger study."

Dr. Wintermark said that he would be curious to know if there is a repair mechanism at work when the players stop playing soccer for a while.

"Perhaps the effect of heading is not cumulative because of some repair occurring between headings, and lessening or preventing injury might be a matter of not doing too much heading repeatedly in a certain period of time. All of this needs to be studied further before recommendations can be made."

He added that the finding that heading in soccer could cause such brain abnormalities is not surprising.

"When you are a soccer player, you have a lot of these headings, and you accumulate them little by little.... It is not a surprise to realize that this could affect you," said Dr. Wintermark, who confessed that he played a lot of soccer as a kid in Europe.

Dr. Lipton and Dr. Wintermark have disclosed no relevant financial relationships.

Radiological Society of North America (RSNA) 97th Scientific Assembly and Annual Meeting: Abstract SSK 12-04. Presented November 29, 2011.


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