Concussions in women

Abstract

Female athletes have long been thought to be less prone than male athletes to concussions, but researchers are saying female athletes get concussions at higher rates than their male counterparts. The data, however, are controversial, as Carrie Arnold reports. In seminars to local high-school athletes and their parents, Michigan State University athletics trainer Tracey Covassin discusses a variety of topics, from the dangers of overtraining, to more serious matters, such as concussions. When she mentioned the risks of head injury to the parents of the local girls' volleyball team, a father stopped her: “Am I in the wrong place?” he asked. “I thought it was my son playing football that I needed to worry about, not my daughter.” This is a misconception Covassin has been fighting throughout her career. Concussions in females, especially in young girls, have been thought to be a relatively rare occurrence. But the work of Covassin and others is showing that concussions in this group are increasing. In the past 5–10 years, the rate of concussions in female athletes has surpassed that in males, and the resulting brain injuries in females tend to be more severe. However, not all scientists agree; some, like Randall Dick of the American College of Sports Medicine, say that concussions in females have increased, but not at a higher rate than that noted in males. Others argue that, although awareness and proper diagnosis of concussions in women and girls might have increased, the rate of concussions has not. Irrespective of whether actual numbers of concussions in females are increasing, says Robert Cantu, a neurologist and concussion expert at Boston University, improved awareness is very beneficial, because “No head trauma is a good head trauma”. Concussions occur when the head is jerked violently back and forth, either from a direct blow (eg, when a baseball hits the head) or an indirect one (eg, whiplash in a car accident). This injury triggers a metabolic cascade, Cantu explains, that results in a metabolic crisis of ions and neurotransmitters as the brain tissue stretches. To recover from this assault, the brain needs to be rested until symptoms resolve. Irrespective of whether the concussed individual lost consciousness—contrary to popular opinion, many people with concussions remain fully conscious after injury—a concussion can result in headache, dizziness, difficulties with concentration and memory, vomiting, sleep disturbances, and personality changes. For mild concussions, symptoms usually resolve in a few hours or days; in more severe concussions symptoms can linger for months, even years, and result in post-concussion syndrome. The US Centers for Disease Control and Prevention estimates that 1·7 million traumatic brain injuries—including nearly 1·3 million concussions—occur in the USA each year. In view of the fact that many concussions occur during sports, especially in children, teens, and young adults, most of the research on concussion prevalence has been done in athletes. “It's hard to say whether women are getting more concussions now than they were before—there's not much research on trajectories over time,” said Donna Broshek, a neuropsychologist at the University of Virginia. “Any research on women's sports only began after the passage of Title IX,”—the portion of the educational amendments introduced in 1972 that prohibits gender discrimination in education and school sports. Furthermore, reports of male American football players who had begun to show violent behaviour or severe dementia after repeated concussions on the playing field probably contributed to the growing research in and awareness of female concussions. Although campaigns by the National Football League, National Collegiate Athletic Association, and various high-school athletic groups initially focused more on male athletes, says Cantu, awareness began to spread to females. Covassin and Broshek authored some of the initial epidemiological studies of concussions in female athletes. One of the first studies, published in the Journal of Athletic Training, tracked injuries in male and female collegiate athletes in games and practice sessions during 3 years. Covassin and colleagues recorded 14 591 reportable injuries, of which 873 (5·9%) were concussions. Female athletes playing soccer and basketball—which both have identical rules for either gender—were significantly more likely to have a concussion than were males playing those sports, especially during games. Higher rates for concussions in females than in males were also recorded in high-school athletes. Using information gathered from the High School Reporting Information Online sports injury surveillance system, which recorded injuries from 425 high schools across the USA, researchers noted that 8·9% of the 4431 injuries were concussions. 201 concussions were reported from boys' football during a single year—the highest overall number of concussions for a single sport. However, girls' soccer and basketball both had significantly higher concussion rates than the boys' games, and girls' soccer was second only to boys' football in concussion rates. “You're always going to have more concussions in your football and ice hockey players, but when you look at the number of injuries in relation to the amount of exposure an athlete has, there are more concussions in girls' soccer and basketball,” said Covassin. There is no clear reason why females seem to be at a higher risk for concussions than males. “It's really the million dollar question,” said Broshek. A major factor, Broshek says, could be the fact that girls tend to have longer, narrower necks than boys. “If you look at male football players, they have muscles pretty much from their ears down to their shoulders.” A smaller average head size in females might also increase their risk for concussion, because it takes less force to cause a smaller head to move violently and cause brain damage. Although none of the experts who spoke with The Lancet Neurology discounts the significance of concussions in women, they do raise significant caveats about the reports that concussions are actually more common in females. Most studies on concussion incidence and prevalence use concussions that have been reported to athletics trainers or other health officials, which requires the potentially concussed individual to accurately report their potential injury. “It appears that women are more honest in reporting their symptoms, which could mean that there are more concussions in men that we just don't know about,” said Dick. “It's unclear at this point exactly how much this might be skewing the data.” Improved surveillance and diagnosis of concussions in males and females are also likely to be affecting these numbers. Whereas Dick says that concussions in both genders seem to be on the increase, Cantu disagrees: “I don't believe that concussions in girls or guys are increasing. We are just recognising more concussions,” he said. “When girls play the same sports as guys, they are more likely to get a concussion.” Even though Covassin, Broshek, and others acknowledge that females might be more forthcoming about their concussion symptoms than are males, they do not believe this means that females are not still at higher risk for concussions than are males. “There's pretty conclusive evidence that, especially in certain sports, females are at higher risk than males,” said Covassin. When Broshek and colleagues wanted to measure the length and severity of post-concussion symptoms in males and females, they were aware of this issue and therefore relied both on subjective verbal reports of symptoms and on more objective computerised neurocognitive testing. In results published in the Journal of Neurosurgery, Brosheck found that males and females had slightly different post-concussion symptoms, and that the symptoms tended to last longer in females. The most common post-concussion symptoms reported by females were significantly more likely to be problems with concentration, lightheadedness, fatigue, and ‘flyspots’ in their vision. Females also reported significantly more symptoms overall. The increased number of symptoms in females was matched by poorer performance on the neurocognitive tests, even after the subjective post-concussion symptoms had resolved. Females scored lower than did males on all three aspects of the tests: simple reaction time, complex reaction time, and processing speed. Nearly 60% of females were judged by medical experts to have cognitive impairments after concussion, compared with 37% of males. No gender differences were reported at baseline in any of these aspects. Results of a later study by Covassin and colleagues showed similar sex differences in post-concussion symptoms. In her group of 222 high-school and university athletes who had had concussions, Covassin reported in the American Journal of Sports Medicine that females were significantly more likely to report symptoms at 1 and 2 weeks after concussion than were males. Females also scored worse on visual memory tests. In this study, younger athletes also reported more symptoms and took longer to recover from their injury. “While these male and female differences are very interesting, I think the most important thing is to figure out, on an individual level, who is at greater risk for poor outcome,” Broshek said. This is one question that does not seem like it will be answered soon. Although the apparent rise in concussion numbers seems worrying, it could prove beneficial to both male and female athletes. It is possible that more and more medical professionals and coaches are becoming aware of the signs of concussion and are getting injured athletes proper diagnoses. Increased awareness and diagnosis will allow anyone with a head injury to receive the treatment they need for a full recovery. All the experts say that prevention of all concussions will be impossible, but improvement of practice habits and game rules could keep at least some athletes from being injured. The recommendations range from reduction or prohibition of body contact (eg, tackling in men's football) to improvement of knowledge of concussion signs and symptoms in both coaches and parents. Just getting these adults to realise that concussions can also affect girls has been a huge start, Covassin says. “I think people are finally realising that concussions aren't just a male thing,” she concluded.