But the injury also occurs at high rates in many other sports, especially those in which females participate. Furthermore, both men and women can experience a brain injury in circumstances outside of sports, and females may be more vulnerable in some of these areas.
Concussions in Males Versus Females
In recent years, research has shown rising rates of concussions in females. “Research shows the rate of female concussions is rising more than for males,” says Angela Colantonio, PhD, a senior scientist and research division head at the Toronto Rehabilitation Institute. And while this is true in the sports world, there are many other causes of traumatic brain injury, including falls, motor vehicle accidents, and blows to the head. Dr. Colantonio says there are likely many more undocumented brain injuries among women, such as in cases of intimate partner violence. In addition to higher rates of concussion among females, female athletes report a higher number of symptoms and more severe symptoms after brain injury than males. In contrast, male participants in the study had a greater sensitivity to noise and more sleep disturbances than females and reported more difficulty setting realistic goals. Men also reported restlessness as a problem following a concussion. Some experts somewhat controversially explain that social gender differences account for the disparity, for example that females may be more likely to report symptoms of concussion than males. But research shows biology is also likely at work. For example, female athletes may be at greater risk of concussion at certain times during their monthly hormone cycles. In a study, researchers analyzed blood samples from 144 women with concussions to determine the stage of their menstrual cycle. They found that women who were injured during the last two weeks of their cycle (when the hormone progesterone is at its highest level) had worse post-concussion symptoms than those who were in the first two weeks of their cycle (when progesterone is at the lowest level) and those who were taking contraceptive pills. While the researchers could not prove why this happens, they have a theory. When women receive a blow to the head during the last two weeks of their cycle, production of progesterone tends to slow, which creates a sense of withdrawal that makes the symptoms of a concussion like headaches, nausea, and dizziness worse. The study authors refer to this as the “withdrawal hypothesis”; the sudden drop in progesterone when it should be high is what leads to worse concussion symptoms than with concussions that occur with already low levels of progesterone. Importantly, Colantonio notes that the majority of research done on gender differences in traumatic brain injuries is based on athletes, which may or may not translate to the general population or people who get concussions outside of sports. More scientific research is needed in this area, she says.
Because of this, Colantonio says that some females may doubt themselves when the speed of recovery and severity of symptoms following a concussion do not match the experience of males they may know. It’s paramount, she says, that parents, doctors, coaches, and school staff listen to girls and women and the symptoms they report after a brain injury. “In our focus group with women with more severe levels of injury severity, women with brain injury felt dismissed by care providers,” she says. “It’s important for practitioners and parents not to dismiss these symptoms.” Research is underway to determine the effectiveness of patient education materials that take into account sex and gender differences in concussion outcomes.
