It's been established by many studies that women are more vulnerable than men when it comes to head injuries. Women who have experienced a concussion or mild traumatic brain injury (mTBI) have more extended recovery periods.
There are a few possible reasons. Axons, the fibers that stretch out from neurons to carry signals around the brain are smaller in women and break easier than axons in men. There could also be hormones, genetics and body size factors that contribute to this vulnerability.
New research from Albert Einstein College of Medicine in New York shows that in women who play soccer and frequently "head" the ball suffer damage that is five times more extensive than their male counterparts who also hit the ball with their heads.
Michael L. Lipton, M.D., Ph.D., is a professor of radiology and psychiatry and behavioral sciences at Einstein. He is also the medical director of MRI Services at Montefiore Medical Center. He explained, "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. 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."
The study looked at 49 men and 49 women soccer players who were enrolled in the Einstein Soccer Study. The age range of the cohort was between 18 and 50, with a median age of 26. Both the men and the women reported a similar number of headings over the year before the study. Men reported an average of 487, women slightly lower at 469 times they hit the ball with their heads. The study participants underwent a specific kind of MRI, a diffusion tensor imaging (DTI) scan which uses images of the movement and diffusion of water in the white matter of the brain. The scans were evaluated based on a score called fractional anisotropy (FA.) The lower the score, the more severe the damage is to the structure of white matter tissue.
When the scans were all scored, the results showed that the volume, or amount, of damaged white matter in the brains of the female players, was more extensive than in the male players. In the women, there were eight regions of the brain that showed low FA scores (which equals more damage) compared to only three areas that showed a loss in the men.
The lead author of the study, Todd G. Rubin, M.S. is an M.D.- Ph.D. student at the Translational Neuroimaging Lab at Einstein. He stated, "Our study is larger and more evenly balanced between the sexes than any prior imaging study of sex and brain injury. The findings add to the growing body of evidence that men and women express distinct biological responses to brain trauma."
While the FA scores were lower in women, indicating more widespread damage, the authors stressed that there were no "overt clinical findings" of cognitive decline or other neurological symptoms. The damage is still noteworthy, however, and could lead to safety protocols that are different for male and female players. The video below shows scans with areas in red indicating higher FA scores (and lower amounts of white matter damage) and those showing up in blue that show more injury.