Women’s brains appear to be more affected by heading a soccer ball than men’s are, new research shows.
A study using brain scans shows distinct patterns of damage in the brains of female soccer players compared with male players. And women in general had more of their brain matter affected, the researchers reported Tuesday in the journal Radiology.
That doesn’t necessarily translate into symptoms. None of the women in the study had any more symptoms than the men did, said the team at Albert Einstein College of Medicine in New York.
But it may help explain why other studies have shown that female soccer players are more likely to report symptoms of concussion than male players are.
“Researchers and clinicians have long noticed that women fare worse following head injury than men, but some have said that’s only because women are more willing to report symptoms,” Dr. Michael Lipton, a professor of radiology and psychiatry at Albert Einstein who led the study team, said in a statement.
And much of the diagnosis of brain injury is subjective, relying on what people say they are experiencing.
Brain scans get past that problem, Lipton said.
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“Based on our study, which measured objective changes in brain tissue rather than self-reported symptoms, women do seem more likely than men to suffer brain trauma from heading soccer balls,” he said.
Lipton’s team studied 49 men and 49 women who all played in amateur soccer leagues. None had any evidence of head injury.
“Participants were asked how often they headed the ball on average during each type of session (practice vs. competition) and in each setting (indoor vs. outdoor), how many times per week they participated in each, and how many months per year they played soccer,” the researchers wrote in their report.
Then the volunteers got a specialized type of magnetic resonance imaging scan called diffusion tensor imaging. It can show damage to tissue on a very fine scale.
The women who headed more often had eight brain regions that showed damage, while men had three main regions of damage. And more overall brain area tended to be damaged in the women than in the men.
“The fivefold greater volume of affected white matter that we identified in women compared with men pointed to a higher burden of microstructural consequences in female headers,” they wrote.
“Our findings add to a growing body of evidence that men and women express distinct biologic responses to brain injury.”
It is unclear why, but researchers have pointed out that women have smaller necks than men, which could cause the head to move differently, perhaps shaking and damaging the brain in different ways.
There is no debate that heading the ball can cause brain injury. A 2015 study of high school soccer players published in the Journal of the American Medical Association found that heading accounted for 30 percent of concussions in male players and 25 percent of those in girls.
Among adults, as well, heading the ball only accounts for a portion of concussions. Players are also often kicked, slammed to the ground, and whiplashed in the fast-moving game.
It’s important to be able to identify the damage early, said Lipton. Football players, combat veterans and others often suffer a degenerative brain disease called chronic traumatic encephalopathy. There’s no cure for it and concussions appear to be strongly involved.
“In various brain injuries, including chronic traumatic encephalopathy, subclinical pathology develops before we can detect brain damage that affects function,” Lipton said.
“So before serious dysfunction occurs, it’s wise to identify risk factors for cumulative brain injury — such as heading if you’re female — so that people can act to prevent further damage and maximize recovery.”
Heading may not necessarily need to be banned, he said.
“We have carried out several studies showing that most players seem to tolerate some level of heading,” Lipton said.
“Limiting the number of headers allowed in soccer might have similar benefits in preventing head injuries. But we can’t recommend specific numbers at this point. Fully understanding the risk of heading will take a lot more work.”