Introduction

Female athletes are more likely to sustain sport-related concussion than male athletes when playing equivalent sports. Studies on middle-school to high-school females demonstrate that female athletes are at a higher risk of sustaining a concussion than their male counterparts. A landmark study in 2017 by Schallmo et al. was the first to report both gender differences and sport-specific differences in concussion. Despite significant educational efforts, athletes continue to underreport concussion symptoms. This chapter will discuss the evolving evidence surrounding gender differences in concussion, current trends, and future directions.

Clarifying Terms

Since 2001, an international conference involving multidisciplinary experts has convened every 4 years to create an expert, consensus-based approach on how to review, discuss, and study concussion as it relates to sports. Following each meeting, this group has produced a consensus paper with guidelines on the definitions, diagnosis, evaluation, and management of concussion.

It is important to note the evolution of the term, “sport-related concussion (SRC)” versus “concussion.” Concussion is a broad term applied to immediate and transient symptoms of traumatic brain injury (TBI). Between the fourth and fifth International Conference on Concussion in Sport, SRC was more precisely described as, “a traumatic brain injury that is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces with several common features that help define its nature”. ^, A consistent goal of the International Conference on Concussion in Sport is to streamline SRC definition, eliminating designation of severity ratings of concussion (i.e., mild vs. complex).

This definition is incredibly important not only for the clinician but also for the patient to understand. Important points from the Consensus Statement for the definition of SRC include the following:

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  SRC is an injury occurring as an induction of biomechanical forces.

  
  
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  SRC can be caused by a direct blow to the head, face, neck, or elsewhere in the body (i.e., whiplash-type mechanism).

  
  
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  SRC is a short-lived impairment of neurologic function, which resolves spontaneously. Special note should be taken, as both signs and symptoms can evolve over a period of minutes to hours.

  
  
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  SRC results in many neuropathologic changes, but the more acute signs and symptoms manifest as a very functional change/disturbance versus a true structural change. This means that no abnormality is seen on a standard neuroimaging study, such as a magnetic resonance imaging or a computed tomographic scan.

  
  
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  SRC may or may not involve loss of consciousness.

  
  
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  SRC signs and symptoms will resolve over time with a “sequential course”; however, they can be prolonged in some cases.

  
  
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  To clinically define a head injury as an SRC, the signs and symptoms need to be defined outside influences such as drug, alcohol, or medication use; other injuries; and/or other comorbidities.

The understanding of concussion is further complicated by it being largely a clinical diagnosis rather than a diagnosis based on an abnormal imaging study or a laboratory result. Additionally, concussive symptoms, which help form the clinical diagnosis, are graded on a spectrum of severity from 1–6, rather than on black-and-white answers of yes or no.

Sport-Specific Differences

In the popular press, concussion has long been portrayed largely through the eyes of male-dominated sports (e.g., football, boxing, combat sports, rugby, and ice hockey). These sports may appear to have a higher risk of contact and collision, making it seem as though male athletes are more affected than females. However, when considering sports such as soccer, with similar rules for male and female athletes, some studies show an increased incidence of concussions in females compared with males. In 2016, Covassin et al. compiled injury surveillance data between the years 2004 and 2009 to evaluate gender-related differences in concussion rates and time loss from sport among National Collegiate Athletic Association (NCAA) athletes. This data yielded specifics about concussion rates among more traditional varsity sports such as soccer, basketball, ice hockey, lacrosse, softball, or baseball, showing increased risk for concussion in females. Using this NCAA Injury Surveillance Program, when specifically looking at gender-comparable sports, the authors found that females had an increased rate of concussion of 1.4 times higher overall than males. In addition, greater concussion rates were seen in women’s baseball/softball, basketball, ice hockey, and soccer, as well as more time loss from sport due to concussion in female soccer and basketball players, as compared with males.

Female athletes who play soccer seem to be at a particularly high risk of sustaining concussions. The United States has more registered female soccer players than all other countries combined, from youth athletes to professional teams. Weber et al. analyzed concussion injuries sustained by female collegiate soccer players in NCAA Division I athletics from the 2004 to 2017 seasons. Overall, the authors reported an average of 1.79 diagnosed concussions per year and an average annual incidence rate of 6.56% over the 14-year period. In 2017, Schallmo et al. evaluated high-school athletes to determine gender- and sport-specific trends in concussion injuries among them. Injury data was collected between 2005 and 2015, including all athletes participating in boys’ football, boys’ and girls’ soccer, girls’ volleyball, boys’ and girls’ basketball, boys’ wrestling, boys’ baseball, and girls’ softball. This landmark study was the first to show that women’s soccer has an even greater risk of concussion compared with all other sports. ^, This data highlights the need for not only expanding concussion protocols and prevention methods and improving the understanding of concussion in females but also evaluating concussions in female athletes in a more sport-specific manner.

Girls’ lacrosse brings up many similar points and discrepancies between genders. Lacrosse is a sport played by both genders, but there are some stark differences in terms of rules and protective equipment. In boys’ lacrosse, full-contact body checking and stick checking is allowed. However, in girls’ lacrosse, full-contact body checking is prohibited, but stick checking is permitted with restrictions. The “halo” or sphere rule applies in girls’ lacrosse, dictating an imaginary sphere of 7 inches surrounding the athlete’s head, which is not to be touched. In addition, the protective gear worn by male and female lacrosse players is different, with male athletes being required to wear hard-shell helmets with full face masks, mouth guards, shoulder/arm pads, and padded gloves, whereas female athletes have to wear only mouth guards and protective eyewear. Owing to the play rules mentioned earlier, girls are prohibited from wearing the hard-shell, full-face-masked helmet. Despite these rules, greater concussions in female lacrosse players occur by contact with the stick or ball than by direct player contact. This discrepancy raises the question of whether girls should be allowed to wear full hard-shell helmets, given the high risk of concussion that has been demonstrated in several studies.

Many of our existing studies evaluating gender-related differences in concussion focus on more “traditional” varsity sports (e.g., soccer, basketball, lacrosse, and softball). However, there are several female-dominated sports (e.g., ballet and figure skating) that are not routinely studied but involve a high rate of concussion. These activities involve significant rotational components, which is a noteworthy aspect of investigation surrounding the mechanism of injury of concussion. In 2015, Post and Blaine Hoshizaki performed a review that studied mechanisms of concussion injury by investigating the relationship between rotational acceleration and brain tissue strains, which are said to be the root cause of concussion. The authors described that this relationship is important to take into account when determining ways to reduce the risk of concussion, but further research is warranted to clarify the role of all aspects of head kinematics, including linear components, in concussion mechanisms, prediction, and prevention.

Unique Features of Concussions in Female Athletes

Females tend to have a higher number of symptoms on the concussion grading scale at the time of initial presentation. On concussion grading scales, symptom factors can be grouped into the following categories: (1) cognitive (difficulty concentrating, difficulty remembering, feeling mentally “foggy”), (2) emotional/affective (irritability, sadness, nervousness), (3) physical/somatic symptoms (headache, nausea, vomiting), and (4) sleep (trouble falling asleep, sleeping less than usual). Several studies have shown that females report greater symptoms among all symptom categories compared with their male counterparts. ^, Clair and colleagues observed symptom expression during concussion recovery in a pediatric population. The researchers found that in females, physical and cognitive symptoms presented more acutely (1- to 12-week time frame) following a concussion, as opposed to males. In later time periods (i.e., longer than 12 weeks after sustaining a concussion), males experienced higher physical and cognitive symptoms. Concussive symptoms tend to take longer to resolve in female athletes. ^, Specifically, females have shown to take longer time to return to school without accommodations, to return to noncontact exercise, for full return to sport, to recovery on computerized neurocognitive function, and for full recovery of vision and vestibular dysfunction.

Neuropsychologic testing demonstrates that female athletes struggle with more cognitive difficulties, worse emotional symptoms, and poorer visual memory than males following concussion. ^{, , ,} Furthermore, significantly different outcomes in reaction time and concentration after concussion have been found when comparing the two genders. In their review of the role of gender in assessing and managing SRC, Covassin and Elbin mentioned that a proposed explanation for the variations in symptoms that exist is related to the differences in the nature of self-reporting symptoms between males and females. Previous studies have shown that female athletes are more concerned about their future health than males, while male athletes are pressured to show toughness and play through pain. These general findings of differences in sports environments can be translated to the setting of self-reporting concussion symptoms, where female athletes are more likely to report concussive symptoms, explaining in part the observed gender-based disparities in concussion symptoms.

Vestibular/Ocular Motor Screening (VOMS), a patient-reported symptom provocation measure, was developed to better assess both vestibular and oculomotor dysfunction in patients following concussion. This screening includes assessments in the following areas: (1) smooth pursuit, (2) horizontal and vertical saccades, (3) convergence, (4) horizontal vestibular ocular reflex, and (5) visual motion sensitivity. Female athletes frequently demonstrate greater symptom provocation with vestibular and ocular testing. Specifically, utilizing VOMS, females were shown to often perform worse than their male counterparts. ^, Females show delayed time to regain both vestibular and oculomotor deficits with smooth pursuits, saccades, gaze stability, near point of convergence, and balance. Understanding this critical information is important when evaluating the concussed female athlete, as it directly relates to not only patient symptoms but also findings on physical examination, which will help guide the development of treatment plans.

The notable gender-based differences in vestibular and oculomotor dysfunction in combination with females typically presenting to specialty care for evaluation after SRC later than males are concerning. This delay in obtaining proper care has been correlated to the prolonged recovery following concussion that is observed in females when compared to males. As a result, with greater time and subsequent challenges to the reestablishment of proper eye tracking and vestibular function, female athletes will experience difficulties with reading, retaining information, and learning for a longer period. Overall, these effects produce physical symptoms manifested as fatigue, sleep irregularities, headache, and nausea. Therefore it is difficult to determine how much of the emotional symptoms of irritability, depressed mood, and anxiety are truly psychologic versus how much have their roots in oculomotor and vestibular dysfunction.

Concussion in Females Beyond the Athlete

As we understand more about the differences between concussion in males and females, it is imperative to better understand the impact of concussion in females outside sports. Specifically, it is important to remember that concussions in females can happen outside the sporting arena. Females are more likely to be involved in domestic abuse situations, which can span across all races, ages, socioeconomic levels, education levels, and sports. According to the CDC’s National Intimate Partner and Sexual Violence Survey (NISVS), about one in four females will experience sexual violence, physical violence, and/or stalking by an intimate partner in their lifetime. This is in contrast to 1 in 10 males who will experience this type of violence. In addition, this violence can start as early as adolescence, with 11 million females and 5 million males reporting their first incidence of violence at an age less than 18 years. Therefore injury can date back even before a college athlete presents to a student health or physician’s office with symptoms. These violent episodes can not only directly result in concussion injuries but also contribute to other lasting mental health challenges, such as depression, anxiety, and posttraumatic stress disorder (PTSD). Furthermore, traumatic events like abuse can increase the possibility of patients engaging in higher risk behaviors such as smoking, binge drinking, and higher risk sexual behavior. These underlying issues, in addition to a concussion injury, make for an even more challenging situation. Therefore when working with female athletes who present with symptoms consistent with concussion, inquiring about the risk of abuse should not be overlooked.

The underresearched area of concussion caused by physical abuse carries significant weight when considering concussion in females. SRCs can certainly produce multiple concussions, but intimate partner abuse can result in far greater numbers of concussions/TBI over time. It is not intuitive in the sporting context to think of the potential for athletes to have sustained a head injury from a physical abuse situation. This remains, however, an opportunity for healthcare providers surrounding these athletes to create treatment environments that support athlete disclosure related to potentially sensitive and emotional circumstances.

For future areas of continued study and the expansion of concussion assessment, establishing an informative link between SRC and intimate partner violence (IPV) could be very insightful. Determining their respective influences in both diagnosis and treatment could help further understand the gender differences in concussion. Smirl et al. examined the degree of overlap between SRC and IPV symptoms pertaining to TBI in a population of female IPV survivors. Researchers compared the Brain Injury Severity Assessment (BISA) tool, an IPV-specific questionnaire, and the Sport Concussion Assessment Tool 5 (SCAT5), which is widely used for SRC evaluation. Overall, it was found that in females who have experienced IPV, a greater number of TBIs were detected when using the BISA tool. Traditionally, an SCAT-5 might not be included in the initial assessment of a female who has sustained IPV. The opposite is also true, where an athlete who has sustained a head injury may not be screened for potential IPV. Therefore the results from these authors indicate the potential for an enhanced ability to diagnose TBI by expanding screening tools used for athletes to include IPV-specific questionnaires, in addition to the SCAT-5 tool. Furthermore, by including psychopathologic assessments for PTSD, depression, and anxiety, sports medicine teams may be able to gain a better understanding of the true incidence of TBI and assess the overall severity of these injuries.

Although research such as this helps frontline staff to further identify TBI incidence and other challenges facing IPV survivors, the same should also be true for the sports medicine community. This calls upon sport medicine physicians, athletic trainers, and other staff to understand the need to incorporate a more expansive view of the female athlete presenting with concussionlike symptoms. A female athlete who presents with symptoms of difficulty concentrating, fatigue, and “not feeling like themselves” very well may have concussion, but may also be a victim of abuse. As we learn more about the state of various forms of abuse that may be affecting athletes, it becomes clear that there is a stigma around reporting not only mental health issues but also abuse. Even concussion itself continues to go underreported by female athletes in many sporting situations as a result of stigma. Intertwining these stigmas with the additional aforementioned concerns, continued education surrounding the importance of all three of these issues (abuse, mental health, and concussion) is essential for the clinician to prioritize. Sports medicine providers need to create clinical environments that promote mindfulness of the possibility that female athletes can be at a greater risk for concussion from violence or abuse versus solely from SRC. In this environment, female athletes could also use the guise of potential diagnosis of concussion to get symptoms addressed from undisclosed abuse.

Yet another interesting facet of understanding concussions in female athletes involves the female military personnel population. Beginning in 2014, the fusion of two very similarly at-risk patient populations, collegiate student-athletes and military service academy students, formed the first large-scale prospective study on concussion and repetitive head injury. ^, The ongoing study, dubbed the Concussion Assessment, Research, and Education (CARE) Consortium, was launched and jointly funded by two organizations, the NCAA and the Department of Defense (DOD), and includes 30 campuses across the country. As both a clinical and neurobiological study, this incredible collection of data will be the first of its kind and will hopefully promote even more research based on its impending findings. Data and parameters will be measured with a sequence of tests at the immediate hours, days, and weeks from the head injury. Baseline testing was performed at the beginning of the study to ensure that new data following head injury has a standard of comparison. In addition, a secondary arm of the study will include following up patients long-term after they leave the college setting and for up to 4 years after they leave either their collegiate sport or their service academy career.

Among the active population in a collegiate setting, both student-athletes and military personnel are not only alike in age but also highly motivated with similar reasons to potentially conceal their symptoms for fear of being taken out of activity. In both collegiate-level sports and military training, the risks and potential ramifications for the participant of sustaining a concussion can create difficulties with self-reporting, despite the extensive focus on education over the past decade. ^, Athletes have stated that they weigh the cost and benefits when considering reporting suspected concussive symptoms. Keeping in mind the health consequences of the potential concussion, they also worry about the impacts on their team if they are removed from play and receiving negative reactions from their teammates and coaches. These concerns are in addition to the potential cultural issues that surround various sports regarding performance pressures and expectations. Although at present athletes receive significantly more education and have greater access to assistance than in the previous years, there are still substantial barriers to reporting concussion for fear of negative consequences.

A study by Rawlins et al. analyzed the factors influencing concussion reporting in the United States Air Force Academy (USAFA) cadets. The researchers divided outcomes according to themes, which included perceived costs to physical fitness, military career aspirations, pilot qualifications, sports, reputation, academics, and lack of time. This study not only highlighted the complex nature and environment that these cadets must navigate but also illuminated a different barrier to reporting, with concern for future career ambitions. In finding a solution to these barriers, researchers suggested gearing more education toward helping cadets realize the importance of reporting concussions earlier, which in turn will get them back to military and sporting activity sooner. Intentional messaging around the themes identified to prevent reporting could also help minimize attempts at self-management of concussive symptoms. Based on this study, continuing to debunk the stigma surrounding concussion disclosure would lower the fear of cadets’ reputation being impacted and result in a greater inclination for this population to seek out necessary care.

Register-Mihalik and colleagues looked at concussion education and reporting in first-year cadets, where 29% were also NCAA student-athletes and, notably, only 21.7% of the entire population studied were female. This study focused on using increasing concussion education as a tool to improve concussion disclosure among cadets. The authors found an association between being female and having lower odds of multiple concussion education exposures. In the same study, however, a history of sport participation increased the likelihood of having received concussion education on multiple occasions through a variety of formats. More specifically, having played a contact sport in high school was tied to a greater likelihood of multiple education exposures, as did having a history of more than one concussion. Worth mentioning, however, females in this population were less likely to have a history of sustaining multiple concussions. This particular study did not directly correlate more exposure to concussion education to increased knowledge, better attitudes, improved perceived norms, or higher intention to disclose concussion history. However, it did show that for those with a concussion history, exposure to multiple sources of concussion education had a nearly 40% increased prevalence of disclosing all concussions at the time of injury. This was in contrast to those who had only one source of concussion educational exposure. Furthermore, the female athlete/cadet may or may not have had the education exposure as those athletes who participate in contact sports, ultimately limiting her opportunity to receive proper, adequate concussion education, which should not be a deficiency in the female athletic or military experience. Moving forward, this information should motivate sports medicine departments and military programs involved at the collegiate level to ensure that all females continue to receive additional concussion education, as they may not have previously received it in high school. By correcting the disparity in the amount of concussion education exposure across all genders and sports, programs could improve concussion-related reporting and decision-making at the critical transition into collegiate athletics.

The Female Body and Concussion Differences

The female brain is different than male brain in its composition and biochemistry, and the female physical body also has several variations. Research has shown that female and male brains differ in more than 100 ways involving structure, activity, chemistry, and blood flow. Concussion affects all parts of the human body, including the brain and physical anatomy. Therefore taking a deeper dive into these gender-based differences is yet another important step in developing a better sense of concussion in females.

Understanding how female physiology may play a role in the concussion experience is one of the most underresearched topics facing the female athlete population. Female physiology provides constant fluctuations in daily hormonal status. Based on research performed on female athletes and anterior cruciate ligament injury risk, it is known that estrogen has effects on the musculoskeletal system with respect to muscle function and tendon and ligament strength. In addition, the female sex hormones, estrogen and progesterone, affect temperature regulation, central nervous system fatigue, substrate metabolism, and exercise performance. Female athletes of all levels, from high school through Olympic and professional sport, note changes in their performance as well as the need for different nutrition, recovery, and injury prevention at various points in their monthly menstrual cycle. How these all relate in the setting of concussion is still largely unknown. Growing numbers of case reports in the literature point to the potential of an altered neuroendocrine relationship in the postconcussion time frame. In 2019, Di Battista et al. evaluated correlations among levels of various neuroendocrine hormones, symptom burden based on the SCAT-5 questionnaire, and recovery time represented by time to physician medical clearance in a population of collegiate-level athletes participating in several different sports. Researchers clustered concussive symptoms into groups (somatic, cognitive, fatigue, and emotion) and observed their relationships to hormone levels, finding that lower levels of both dehydroepiandrosterone sulfate (DHEA-S) and progesterone were associated with an increased symptom burden and longer recovery times. Abnormally low cortisol levels were also reported to have similar effects. Interestingly, in cases of moderate to severe TBI, progesterone has been shown to have neuroprotective effects and other therapeutic benefits. However, owing to the complexities of TBI, there are varying conclusions about the true effect of progesterone, with contradictory results indicating that it likely still has mechanisms involved in injury pathophysiology. Furthermore, at low levels of DHEA-S and progesterone in the setting of concussion, results showed greater mood symptoms corresponding to the presence of higher emotion-related symptom scores. This can be related to the general finding of improvements in mood and behavior seen with higher levels of both these hormones. The authors of this study also reported a positive correlation between prolactin hormone levels and recovery time, with higher levels of prolactin associated with more time to medical clearance and greater cognitive symptom reporting. The previously established relationship between elevated levels of prolactin following severe TBI was noted, as well as these results contradicted earlier studies, indicating the need for further research on the role of prolactin in concussion recovery.

The aforementioned study did not control for menstrual cycle phase in the female athletes included, making it difficult to analyze the potential effect of menstrual phase at the time of concussion on the concussion experience and recovery. Few studies have addressed menstrual phase as a predictor of concussion outcomes in SRC; however, Wunderle and colleagues studied this in 2014 among a population of females presenting to the emergency department with mild TBI. Researchers observed that females injured during the luteal phase of the menstrual cycle, indicated by increased progesterone concentration, experienced worse postconcussive symptoms and poorer quality of life at 1-month after injury compared with those injured during the follicular phase (low progesterone concentration). The authors posited that this occurs as a result of a sudden decrease in progesterone levels at the instance of injury, whereas preexisting low levels of progesterone seen during the follicular phase do not create the same sudden effect and, therefore, lead to better outcomes. This also in part explains gender-based differences in concussion symptoms, given that males have consistently low levels of progesterone and cannot experience the same abrupt fluctuation that is related to poorer outcomes in females. Interestingly, the same study found that females taking synthetic progestin as birth control reported greater quality-of-life outcomes, similar to females injured during the follicular phase, because of the consistency of high levels of progestin before and after injury.

Understanding specific relationships between concentrations of female hormones and systemic inflammation may help clarify differences in concussion symptoms and severity between males and females. A study by Di Battista et al. reported evidence of a significant association between levels of inflammatory biomarkers and symptom burden among all symptom clusters (somatic, cognitive, sleep, and emotion), showing differing results in female and male athletes. Future studies investigating the nature of gender-specific variations in symptom presentation and their potential relationships to female hormones are important for improving prognosis and management.

Evolving evidence surrounding gender-based musculoskeletal differences shows that these differences may also be important in how males and females experience concussion. Specifically, neck size, strength, and strength-to-head size ratios differ between the genders. ^, Decreased neck strength coupled with additional factors, such as greater peak angular acceleration and increased angular displacement, could all combine to give female athletes a “bobblehead” phenomenon. Combining this information with considerations regarding sport type, mechanisms of injury, and sport demands brings us closer to understanding the role musculoskeletal deficits may have in female concussion. Soccer serves as an excellent example in understanding the pivotal role the head-and-neck anatomy have in concussion. The activity of heading in soccer has long come under fire as a large contributor to concussion. In soccer, both collisions and headers are well documented as sources of concussion that occur during both practice and competition/games. Some studies have shown up to 40% of concussions occurring in practice and 40% of those caused by headers. Addressing the relationship between this type of heading activity and concussion has shown growing support. There is value in not only changing how players are practicing with headers by incorporating more technique-focused repetitions but also placing limits on the number of repetitions in a given period. This would be a similar idea to following pitch counts in young baseball players, which ultimately limits harmful amounts of repetitions and ensures a proper rest and recovery period to avoid injury. Integrating neck strengthening and cervical proprioception into practice and training is yet another option to help combat this sport-specific risk of concussion in female athletes. Future studies geared toward establishing better tracking using impact monitors to evaluate frequency and strength of these contact episodes would help broaden our understanding of the cumulative effects of this type of activity. Thus combining knowledge of the differences in head/neck strength in females, cervical proprioception, and more precise data collection might help form more prospective, preventative strategies for female athletes.

Given the higher prevalence of concussion in females than males, observations regarding the actual play of different sports become important despite what popular press headlines read focusing on male-dominated sports. Drawing comparisons between female and male sports can be difficult, as not only can the sport itself but also the rules and protective equipment involved be different. However, interesting enough, when comparing sports that have somewhat similar rules and play, such as basketball and soccer, the gender-based differences in the mechanism of concussion injury are sustained. Across these types of sports, males tend to have a higher incidence of concussion from direct player contact, whereas females are more likely to have a concussion from contact with the ball or surface. ^, Relating position to concussion incidence is relevant in creating additional protection for these high-risk female athletes. Better understanding of the specific scenarios where female athletes are at a greater risk of sustaining a concussion can help create additional education points for coaches, players, and referees. For example, concussions in soccer occur at higher rate during games than practice, and this information can help implement improved education to referees for better enforcement of rules as well as limit harmful contact between players. These are just some of the tactics that could be useful in preventing concussions in a more sport-specific manner, and these concepts can be generalized and expanded across all sports.

As concussion is a clinical diagnosis, symptom reporting is a consistent measure across all concussion types by which conclusions can be drawn. When looking at the specifics of these concussive symptoms across studies, females fair worse in 85% of measured symptoms, consisting of poor memory, dizziness, fatigue, sensitivity to light and noise, impaired concentration, headache, anxiety, and depression. Additionally, formal neurocognitive testing in females continues to show concerning data. Broshek et al. evaluated gender differences in neurocognitive outcomes following concussion in both high-school and college athletes. Compared with males, females showed significantly greater cognitive declines based on measures of simple and complex reaction times after concussion versus their preseason baseline levels. Concussed female athletes have also shown significantly lower visual memory composite scores and perform worse up to 72 h after concussion compared with their male counterparts. Furthermore, females continue to report more postconcussion symptoms and for longer periods compared with similar age-matched males, and they may exhibit longer neurocognitive impairments indicating potential long-term effects of SRC. While the issue of “baseline testing” itself creates great debate among providers, these comparisons at a minimum highlight another area of research needed to understand why these differences exist in females.

Moving Toward the Future

When considering ways for sports medicine teams, healthcare providers, military campuses, and schools to improve female athlete care, understanding and reviewing stigma and myths around the diagnosis of concussion continues to be crucial. Even outside the healthcare community, it is fair to say there is common knowledge that athletes knowingly play with concussion symptoms. A study of male and female high -school athletes demonstrated that over half of the athletes (60%) had played in practice or during a game with concussion symptoms. This data is concerning as athletes continue to underreport concussions despite the tremendous efforts and advancements in concussion management, treatment, and education for both players and coaches over the past decade. Moving forward, creating educational forums specifically targeting the female audience has the potential to increase self-reporting and ultimately improve care for the female athlete. Evolving evidence shows that females also experience the stigma surrounding concussion, but studies indicate that females are more willing to report symptoms and have a greater intention to actually report compared with their male counterparts. However, they may also have reduced access to concussion education, in comparison with males, prior to the collegiate experience. This is a critical window for implementing interventions and addressing these gaps, as females possess the potential for increasing concussion knowledge and the capacity for direct reporting and continue to push the boundaries of participation in sports and military activities.

For future studies, it will be important to identify and correct the large test bias that often exists in the majority of concussion-related studies, which often lack female representation. Even in the case of postmortem brain studies, there is a significant male bias, as there are almost no female brains included in published research on chronic traumatic encephalopathy. Research should be aimed at looking at how concussion studies are designed, conducted, and interpreted so that more accurate information can be gained in understanding the differences between concussion in males and females. Large-scale projects, such as the NCAA and DOD CARE Consortium, will likely provide vital information that will improve the lives of female athletes who sustain a concussion.

As we expand beyond sport-related concussion in females to include military personnel and victims of abuse, it will be essential to identify other associated diagnoses that may be present alongside concussions, such as depression, anxiety, and PTSD. The intricate interweaving of these diagnoses and how they pertain specifically to females is crucial. Expanding education on these subject matters and enhancing screening for both concussion and other related conditions will be critical for improving the care of female patients. Furthermore, utilizing a multidisciplinary team of providers will deliver more thorough and well-rounded care to female athletes. Just as the female body is complex and multifaceted, so needs to be the team that cares for and guides treatment of female athletes. The sports medicine provider may be at the heart of the concussion team, but additional access to psychologists, psychiatrists, sports nutritionists, physical therapists, massage therapists, optometrists, and speech therapists will provide female athletes with the highest level of care.

Now is the time for researchers and healthcare providers to band together to move the female athlete forward. As mental health is so pivotal to the overall health of athletes and patients, continuing to educate and help clinicians understand the closely intertwined relationship of psychologic pathology and concussion is key. Ensuring emotional symptoms are not mislabeled as anxiety and depression, but rather thoroughly investigated as potential concussive symptoms, will help identify and not overlook concussion in females. Bridging the gap between concussion in female and male athletes is the next step in understanding not only females in sports medicine but also concussion in a broader sense. By accomplishing this, clinicians will be an essential part of helping female athletes participate and stay in sport and ultimately build a foundation of positive self-image, confidence, and lifelong pursuit of physical activity.