Sex-Based Differences in the Incidence of Sports-Related Concussion: Systematic Review and Meta-analysis

Perturbations in risk/reward decision making and frontal cortical catecholamine regulation induced by mild traumatic brain injury

Mild traumatic brain injury (mTBI) disrupts cognitive processes that influence risk taking behavior. Little is known regarding the effects of repetitive mild injury (rmTBI) or whether these outcomes are sex specific. Risk/reward decision making is mediated by the prefrontal cortex (PFC), which is densely innervated by catecholaminergic fibers. Aberrant PFC catecholamine activity has been documented following TBI and may underlie TBI-induced risky behavior. The present study characterized the effects of rmTBI on risk/reward decision making behavior and catecholamine transmitter regulatory proteins within the PFC. Rats were exposed to sham, single (smTBI), or three closed-head controlled cortical impact (CH-CCI) injuries and assessed for injury-induced effects on risk/reward decision making using a probabilistic discounting task (PDT). In the first week post-final surgery, mTBI increased risky choice preference. By the fourth week, males exhibited increased latencies to make risky choices following rmTBI, demonstrating a delayed effect on processing speed. When levels of tyrosine hydroxylase (TH) and the norepinephrine reuptake transporter (NET) were measured within subregions of the PFC, females exhibited dramatic increases of TH levels within the orbitofrontal cortex (OFC) following smTBI. However, both males and females demonstrated reduced levels of OFC NET following rmTBI. These results indicate the OFC is susceptible to catecholamine instability after rmTBI and suggests that not all areas of the PFC contribute equally to TBI-induced imbalances. Overall, the CH-CCI model of rmTBI has revealed time-dependent and sex-specific changes in risk/reward decision making and catecholamine regulation following repetitive mild head injuries.

Gender differences in concussion-related knowledge, attitudes and reporting behaviors of varsity athletes

BACKGROUND

Concussion is a pathophysiological process that occurs due to a traumatic biomechanical force. Concussions are an "invisible" and common traumatic brain injury with symptoms that may be underestimated. This necessitates fundamental improvements in public knowledge specifically addressing young university athletes and different genders. This cross-sectional study aimed to explore the possibility of gender differences with respect to university student athletes' concussion knowledge, attitude and reporting behaviors. We hypothesized that there should be no significant difference in concussion knowledge among male and female student athletes; however, females would show a more positive attitude and more reporting behaviors than male student athletes.

METHODS

Overall, 115 university athlete students completed a survey questionnaire; we eliminated some participants based on required inclusion criteria of Rosenbaum Concussion Knowledge and Attitude Survey-student version (RoCKAS-ST). Our final analysis consisted of 96 participants: 20 males (mean age 21.15 years) and 75 females (mean age 22.36 years). This study included questions about the athletes' given reasons for reporting or not reporting a concussion. Additionally, 33 RoCKAS-ST questions on Concussion Knowledge Index (CKI) with fair test-retest reliability (r=0.67) and 15 items on Concussion Attitude Index (CAI) with satisfactory test-retest reliability (r=0.79) were provided.

RESULTS

Males reported more sources for learning about concussions and more sport-related reasons for reporting a concussion than females (P<0.05). Both genders provided equal numbers of reasons for neglecting a concussion report or not disclosing a concussion for the sake of others (i.e., family, teammates or the coach). Out of 16 given reasons for not reporting a concussion, males significantly chose sport-related reasons over female athletes (P<0.05). Additionally, by looking at the two components of RoCKAS-ST, the independent t-test results showed no significant gender-based differences in concussion knowledge and attitude indices (P>0.05). Nevertheless, females were less optimistic about evaluating other athletes' attitude over concussion reporting (P<0.05).

CONCLUSIONS

Our study indicated that concussion knowledge is not gender biased among Canadian university athletes; however, more investigation is required to learn how safe environments for concussion disclosure could encourage reporting the symptoms in varsity athletes, especially in males who are more susceptible to not reporting a concussion to not miss their sport-related goals.

Use of the concussion check protocol for concussion assessment in a female soccer team over two consecutive seasons in New Zealand

AIM

Address deficiencies in access to sports sideline medical care by using a Concussion Check Protocol (CCP) for non-medically-trained people.

METHOD

A prospective observational cohort study was undertaken on a single amateur female club-based soccer team over two consecutive years in New Zealand utilising a non-medically trained support person termed a Safety officer. CCP is an extension of the King-Devick test with features such as warning signs and symptoms of concussion built into the application. All players suspected of having a potential concussive injury were tested on the match sideline.

RESULTS

The study overall incidence of match-related concussions was 20.8 (95% CI: 11.8 to 36.6) per 1000 match-hrs, with mean missed-match duration of 31 (95% CI: 27.9 to 34.1) days. Twelve players over the study had a significantly slower post-injury KD (49.9 [44.3 to 64.1]s; χ2(1) = 11.0; p = 0.0009; z = -2.9; p = 0.0033; d = 0.30) and/or reported symptoms, compared with their own baseline (47.2 [44.3 to 64.1]s). CCP had an overall sensitivity of 100% (95% CI: 73.5% to 100.0%), specificity of 100% (95% CI: 69.2% to 100.0%) and positive predictive value (PPV) of 100% (84.6% to 100.0%).

CONCLUSION

Sideline use of CCP was undertaken successfully by non-medically trained people and provided a reliable platform for concussion identification.

Association between days for concussion recovery and initial specialty clinic evaluation within 48 hours

BACKGROUND

Researchers have highlighted the importance of early access to concussion care within one week of injury in reducing recovery times. However, a persisting question for concussion researchers is "just how early is important?" The purpose of this study was to examine differences in recovery time as predicted by the number of days elapsed since injury (DSI) to initial evaluation among patients who had access to a specialty concussion clinic within seven days. We hypothesized that DSI group membership, even within seven days, would significantly predict risk of protracted recovery (i.e., beyond 21 days).

METHODS

In this archival study, retrospective data were gathered from electronic medical records between September 2020 to March 2022. Records of participants between ages 12-18, those diagnosed with a sports-related concussion based on initial clinic visit diagnosis by a medical provider and those who established care within seven days of injury at a large pediatric specialty concussion clinic were examined. Participants were divided into three DSI groups (patients seen in < 48 h: "acute", patients seen between 49 h < and < 96 h: "sub-acute", and patients seen between 97 < and < 168 h: "post-acute"). A general linear model was constructed to examine relationships between relevant concussion factors (e.g., Post Concussion Scale Score, neurodevelopmental history, psychiatric history, concussion history, migraine history, overall VOMS change score, cognitive testing, sex, age, race, and ethnicity) that were either significant in the preliminary analysis or in clinical judgement and recovery time. Adjusted odds ratios (OR) were derived from a binary logistic regression model, in which recovery time was normal (≤ 21 recovery days) or protracted (> 21 recovery days).

RESULTS

A total of 856 participants were eligible. Adolescents in the acute group (M = 15.12, SD = 8.04) had shorter recovery times in days compared to those in the sub-acute (M = 17.98, SD = 10.18) and post-acute (M = 21.12, SD = 10.12; F = 26.00, p < .001) groups. Further, participants in the acute (OR = 4.16) and sub-acute (OR = 1.37) groups who accessed specialty concussion clinics within 48 h were 4 times more likely to have a normal recovery and recovered approximately 6 days faster than the post-acute care group.

CONCLUSIONS

Earlier concussion care access predicted recovery times and was associated with lower risk for protracted recovery.

Sex Differences in Recovery Trajectories of Assessments for Sport-Related Concussion Among NCAA Athletes: A CARE Consortium Study

OBJECTIVES

The purpose of this study was to determine sex differences in recovery trajectories of assessments for sport-related concussion using Concussion Assessment, Research and Education (CARE) Consortium data.

METHODS

National Collegiate Athletic Association athletes (N = 906; 61% female) from sex-comparable sports completed a pre-season baseline assessment and post-sport-related concussion assessments within 6 h of injury, 24-48 h, when they initiated their return to play progression, when they were cleared for unrestricted return to play, and 6 months post-injury. Assessments included the Standardized Assessment of Concussion, Balance Error Scoring System, Brief Symptom Inventory-18, Immediate Post-concussion Assessment and Cognitive Testing (ImPACT), Sport Concussion Assessment Tool-3 symptom evaluation, Clinical Reaction Time, King-Devick test, Vestibular Ocular Motor Screen, 12-item Short-Form Health Survey, Hospital Anxiety and Depression Scale, and Satisfaction with Life Scale.

RESULTS

Only the Vestibular Ocular Motor Screen Total Symptom Score at the 24-48 h timepoint (p = 0.005) was statistically significantly different between sexes. Specifically, female athletes (mean = 60.2, 95% confidence interval [CI] 51.5-70.4) had higher Vestibular Ocular Motor Screen Total Symptom Scores than male athletes (mean = 36.9, 95% CI 27.6-49.3), but this difference resolved by the time of return-to-play initiation (female athletes, mean = 1.8, 95% CI 1.1-2.9; male athletes, mean = 4.1, 95% CI 1.5-10.9).

CONCLUSIONS

Sport-related concussion recovery trajectories for most assessments were similar for female and male National Collegiate Athletic Association athletes except for Vestibular Ocular Motor Screen symptoms within 48 h of sport-related concussion, which was greater in female athletes. Female athletes had a greater symptom burden across all timepoints, suggesting that cross-sectional observations may indicate sex differences despite similar recovery trajectories.

Heart Rate Variability in Concussed College Athletes: Follow-Up Study and Biological Sex Differences

Finding reliable biomarkers to assess concussions could play a pivotal role in diagnosis, monitoring, and predicting associated risks. The present study aimed to explore the use of heart rate variability (HRV) in the follow-up of concussions among college athletes and to investigate the relationships between biological sex, symptomatology, and HRV values at baseline and after a concussion. Correlations between measures were also analyzed. A total of 169 (55 females) athletes aged 16 to 22 years old completed baseline testing, and 30 (8 females) concussion cases were followed. Baseline assessment (T1) included psychosocial and psychological questionnaires, symptoms report, and four minutes of HRV recording. In the event of a concussion, athletes underwent re-testing within 72 h (T2) and before returning to play (T3). Baseline findings revealed that girls had higher %VLF while sitting than boys, and a small negligible correlation was identified between %HF and total symptoms score as well as %HF and affective sx. Post-concussion analyses demonstrated a significant effect of time × position × biological sex for %HF, where girls exhibited higher %HF at T3. These findings suggest disruptions in HRV following a concussion and underscore biological sex as an important factor in the analysis of HRV variation in concussion recovery trajectory.

Knockout rates across the states as a way of predicting injury and knockout based on fighter sex, weight, or experience

Combat sports, such as boxing and mixed martial arts [MMA], have the unique objective to finish a bout by way of knockout [KO] or technical knockout [TKO]. There are potentially both short- and long-term neurological injuries that can happen as a result of the repeated head trauma sustained in bouts, and thus it is imperative to identify the athletes that are at increased risk. Using an online database of professional boxing bouts [boxrec.com] over a 6-month period, KO/TKO rates were calculated across different states, weight classes, sex, and Fight Exposure Score [FES] categories. There was found to be a significant association between KO/TKO rates and weight class, sex, and FES category with heavyweights, males and FES 0 boxers having higher KO/TKO rates. KO/TKO rates were increased in winless boxers. KO/TKO rates across the states are documented in the study.

The Women's Soccer Health Study: From Head to Toe

OBJECTIVES

Women are under-represented in the sports literature despite increasing rates of sports participation. Our objective was to investigate the risks and benefits of an elite women's soccer career in five health domains: general, musculoskeletal, reproductive endocrinology, post-concussion, and mental.

METHODS

An online survey was distributed to retired US college, semi-professional, professional, and national team soccer players using personal networks, email, and social media. Short validated questionnaires were used to evaluate the health domains, including the Patient-Reported Outcomes Measurement Information System (PROMIS), Single Assessment Numerical Evaluation (SANE), Post-Concussion Symptom Scale (PCSS), and Patient Health Questionnaire (PHQ).

RESULTS

A total of 560 eligible players responded to the survey over a 1-year period. The highest competitive levels were 73% college, 16% semi-professional, 8% professional, and 4% national team. The mean number of years since retirement was 12 (SD = 9), and 17.0% retired for involuntary reasons. The mean SANE scores (0-100 scale as percentage of normal) were knee = 75% (SD = 23), hip = 83% (SD = 23), and shoulder = 87% (SD = 21). The majority (63%) reported that their current activity level included participation in impact sports. A substantial proportion of players reported menstrual irregularities during their careers: 40% had fewer periods with increasing exercise and 22% had no periods for ≥ 3 months. The players (n = 44) who felt that post-concussion symptoms were due to soccer reported more time-loss concussions (F[2] = 6.80, p = 0.002) and symptom severity (F[2] = 30.26, p < 0.0001). Players who recently retired (0-5 years) reported the highest anxiety/depression scores and lowest satisfaction rates compared with those who retired 19+ years ago.

CONCLUSION

Health concerns include musculoskeletal injuries, post-concussion symptoms, and lower mental health in the early years following retirement. This comprehensive survey provides initial results that will lay the foundation for further analyses and prioritize research studies that can help all female athletes.

Are Sex Differences in Collegiate and High School Sports-Related Concussion Reflected in the Guidelines? A Scoping Review

Background: Sport-related concussion (SRC) is a common sport injury. Females are participating in sports at increasing rates, and there is growing awareness that female athletes may be more vulnerable to SRC. Objectives: We aimed to identify sex differences in epidemiology, clinical manifestation and assessment of SRC and examine how these relate to the 6th International Conference on Concussion in Sport (ICCS). Methods: We conducted a scoping review of the Medline database and identified 58 studies examining the effects of sex on SRC in collegiate and high school athletes that were written in English and published in a peer-reviewed journal between March 2012 and March 2022. Results: We found that female athletes suffer higher rates of concussion in sex-comparable sports, in particular soccer. Female athletes experience more somatic symptoms-headache/migraine/sleep disturbance-and may take longer to recover from concussion. Sex differences were also identified regarding some aspects of sideline concussion assessment with the Sport Concussion Assessment Tool. Conclusions: Females are at greater risk and experience SRC differently than males; this is mostly likely due to a combination of biomechanical factors, differences in neck musculature and hormonal and social factors. Sex differences are not widely addressed by the 6th ICSS, which informs many sports' concussion protocols.

Revised Dual Task Screen is a Valid Measure of Dual Task Performance: Developing a Motor and Cognitive Dual Task Measure with Healthy Female Athletes

Multitasking measures, such as dual task assessments, are particularly useful in detecting subtle deficits that can influence occupational performance after injuries, like sports-related concussion (SRC). In past work, our research team developed and revised a dual task assessment, the Dual Task Screen (DTS). Here, we evaluated nineteen healthy athletes using the revised DTS to address two specific research objectives. First, to replicate pilot study findings and demonstrate that the revised DTS is sensitive to dual task motor costs (i.e. poorer motor performance under dual task conditions, compared to single task conditions). Second, to evaluate if the revised DTS is sensitive to dual task cognitive costs (i.e. poorer cognitive performance under dual task conditions, compared to single task conditions). We confirmed that the revised DTS was sensitive to both dual task motor and cognitive costs; thus it is a valid measure of dual task performance. These positive findings support its prospective, future use by occupational therapists to evaluate multitasking performance after injuries, like SRC, or other injuries and illnesses that elicit deficits affecting optimal occupational performance.

Efficacy of aerobic exercise following concussion: a narrative review

Concussion is a type of mild traumatic brain injury which results in symptoms within the physical, cognitive, emotional, and sleep domains. Historically, guidelines established by expert opinion have recommended rest during the initial stages of recovery following a concussion until symptom resolution. However, recent recommendations have shifted to advise an initial period of 24-48 h of rest immediately following concussion with the gradual introduction of light-to-moderate intensity aerobic exercise thereafter. Given the relatively recent transition in recommendations, the aim of this review is to provide an overview of the current literature on the efficacy of aerobic exercise following concussion. The current literature is limited to studies assessing the impact of standardized aerobic exercise following concussion. Upon review, literature suggests participating in aerobic exercise below the point of symptom exacerbation is safe in both the acute and chronic post-concussion symptom stages of recovery and does not delay time to medical clearance. Future large-scale randomized controlled trials assessing the impact of aerobic exercise and differences between males and females would help support the current evidence suggesting aerobic exercise could improve time to recovery following concussion and identify any sex differences in response. As well, future studies with the purpose of identifying optimal aerobic exercise volume and intensity in the treatment of concussion could improve the specificity of the current guidelines.

Head Pain in the Competitive Aquatic Athlete-An Approach to a Differential Diagnosis and Management

ABSTRACT

Aquatic athletes not only face common headache etiologies similar to the general population and land-based athletes but also experience their own unique pathology. Posture, aquatic pressure, equipment, and even marine animals pose as unique causes to head pain in the aquatic athlete. Common head pain pathologies seen in the aquatic athlete include tension-type headaches, migraines, cluster headaches, and compressive headaches, including supraorbital neuralgia. Creating a thorough but focused differential diagnosis for head pain in the aquatic athlete can be a difficult and overwhelming task for some. We review both the common and not-so-common etiologies of head pain in the aquatic athlete and suggest a simple framework for assessment and treatment to diagnose and treat head pain in this specific population.

Canadians Reporting Sport-Related Concussions: Increasing and Now Stabilizing

BACKGROUND

Canada is currently engaged in a national harmonization of strategies to prevent and manage sport-related concussions.

OBJECTIVE

To examine the annual incidence rates of reported sport-related concussions or other brain injuries by participants in the Canadian Community Health Survey, a national public health survey which provides nearly 2 decades of serial data using consistent methodology.

DESIGN

Serial cross-sectional survey.

SETTING

Population-based Canadian survey from 2000 to 2018 that collects data on "concussions or other brain injuries."

PARTICIPANTS

Respondents 12 years and older.

INDEPENDENT VARIABLES

Sex and age categorized 12 to 14 years, 15 to 19 years, 20 to 29 years, and 30+ years.

OUTCOME MEASURES

National incidence rates of participants reporting concussions or other brain injuries occurring within the previous year while engaged in "organized sports/leisure sports or physical exercise."

RESULTS

Data were available for 2000/01, 2003, 2005/6, 2009/10, 2013/4, and 2017/8 (N = 757 383). A previously stable annual incidence of reported sport-related concussions or other brain injuries increased nearly 2 and a half-fold from 2005/06 through 2013/14 (P < 0.0001) but seems to have stabilized recently (2013/14 vs 2017/8, P = 0.35). This trend is similar for both men and women but is manifest primarily within youth (12-19 years) as opposed to adults (>19 years). Approximately 1 in 450 Canadians 12 years and older report sport-related concussions or other brain injuries as their most significant injury associated with disability in the previous year (2017-2018: 221 per 100 000 population, 95% confidence interval: 179-264).

CONCLUSIONS

In Canada, the annual incidence rates of reported sport-related concussions or other brain injuries is changing and may reflect improved reporting and recognition.

Characterizing Health Events and Return to Sport in Collegiate Swimmers

Background:

There is limited literature characterizing the incidence, variety, and effects of injuries and illnesses observed in elite swimmers.

Purpose:

To describe the epidemiology of injuries and illnesses affecting elite intercollegiate competitive swimmers.

Study Design:

Descriptive epidemiology study.

Methods:

This retrospective study utilized a deidentified injury and illness database of National Collegiate Athletic Association Division I swimmers in the Pacific Coast Conference from the academic years 2016 to 2017 and 2019 to 2020. A health event was defined as an illness or musculoskeletal injury that was identified by an athletic trainer or team physician. Musculoskeletal injuries and nonmusculoskeletal injuries and illnesses were stratified by body location. Injuries were further characterized as career-ending, season-ending, missed time but the athlete returned to sport in the same season, or those that did not cause missed time. Relative risk (RR) was used to compare the percentage of athletes affected between women and men, with statistical significance being defined by a 95% CI not including 1.

Results:

Included were 641 collegiate swimmers (301 male, 340 female). There were 1030 health events among 277 women and 173 men, with 635 (61.7%) occurring in women and 395 (38.3%) in men. There were 540 musculoskeletal injuries reported, most of which involved the shoulder (n = 126; 23.3%), spine (n = 95; 17.6%), foot/ankle/lower leg (n = 81; 15.0%), knee/thigh (n = 67; 12.4%), and hand/wrist/forearm (n = 52; 9.6%). A total of 490 nonmusculoskeletal health events were reported and included events such as respiratory tract infections (n = 119; 24.3%), unspecified medical illness (n = 93; 19.0%), concussions (n = 58; 11.8%), ear infections (n = 25; 5.1%), and gastrointestinal illnesses (n = 24; 4.9%). Compared with male swimmers, female swimmers were at a higher risk of sustaining both musculoskeletal injury (RR, 1.5; 95% CI, 1.22-1.83) and nonmusculoskeletal injury/illness (RR, 1.32; 95% CI, 1.04-1.68). There were 58 documented concussions, with 8 (13.8%) being season-ending, but not career-ending and 14 (24.1%) being career-ending. Women had a higher rate of concussion (9.1% vs 4.3% for men; RR, 2.11; 95% CI, 1.13-3.96).

Conclusion:

This retrospective study identified the most common injuries and illnesses observed among elite collegiate swimmers. Awareness of the incidence and outcome of injuries and illnesses that affect competitive swimmers may allow for more targeted analyses and injury prevention strategies.

Neurodevelopmental Disorders and Risk of Concussion: Findings from the National Collegiate Athletic Association Department of Defense Grand Alliance Concussion Assessment, Research, and Education (NCAA-DOD CARE) Consortium (2014-2017)

Evidence suggests neurodevelopmental disorders (NDs) may be associated with an increased incidence of concussion, but no studies have cross-sectionally and longitudinally assessed the associations of NDs and sex with concussion in collegiate athletes. We sought to assess the odds and relative risk (RR) of concussion in athletes self-reporting a diagnosis of attention deficit/hyperactivity disorder (ADHD), learning disability (LD), and ADHD+LD. Data from the Concussion Assessment, Research and Education (CARE) Consortium (2014-2017) were used to evaluate the likelihood of concussion for male and female athletes with ADHD, LD, and ADHD+LD, relative to controls. Odds ratios (ORs) of concussion history prior to enrollment and relative risk ratios for incurring a concussion following enrollment, with and without concussion history were calculated for all groups. Athletes with self-reported diagnosis of ADHD, LD, and ADHD+LD were more likely to report a single concussion (OR range = 1.528 to 1.828) and multiple concussions (OR range = 1.849 to 2.365) prior to enrollment in the CARE Consortium, irrespective of sex compared with control athletes. While enrolled in CARE, male athletes with ADHD, LD, and ADHD+LD had greater risk of incurring a concussion (RR range = 1.369 to 2.243) than controls, irrespective of concussion history. Male athletes with ADHD+LD with concussion history (RR = 2.221) and without concussion history (RR = 1.835) had greater risk of incurring a concussion than controls. These results suggest NDs may be associated with increased odds of single and multiple concussions, irrespective of sex. However, when we accounted for concussion history, it appears only male athletes with ADHD+LD had greater risk than respective controls. There were no significant differences between females and males with ADHD, LD, or ADHD+LD for either odds of concussion history or risk for incurring concussion.

Gaps in concussion management across school-aged children

OBJECTIVE

Examine how demographic and injury factors impact identification and management of concussion in students.

METHODS

Prospective observational cohort. Pre-K - 12th grade students within a large, urban school district reported to school with concussion during 2015-2019. Participants were grouped into Elementary/Middle School (E/MS) and High School (HS) and compared by sex, concussion history, injury setting and mechanism, time to medical evaluation and clearance, absences, and recommended accommodations.

RESULTS

154 E/MS and 230 HS students reported to school with physician-diagnosed concussion. E/MS students experienced fewer concussions at school and from sports than HS. More E/MS males than females sustained concussions, while this difference was reversed for HS. Time-to-evaluation was longer for E/MS, specifically female E/MS students and those injured outside of school. E/MS males were cleared more quickly than females. In contrast, no differences were found between sexes for HS by injury setting, mechanism of injury, or management factors.

CONCLUSION

Differences observed in E/MS students by demographic and injury factors are not observed in HS students. Younger students, particularly females or those not injured in school or sports, may be at risk for delayed identification and prolonged time to clearance. Future research should further characterize concussion management in E/MS children.

Epidemiology of Concussions in National Collegiate Athletic Association (NCAA) Sports: 2014/15-2018/19

BACKGROUND

Updated epidemiology studies examining sports-related concussions (SRCs) are critical in evaluating recent efforts aimed at reducing the incidence of SRCs in National Collegiate Athletic Association (NCAA) sports.

PURPOSE

To describe the epidemiology of SRCs in 23 NCAA sports during the 2014/15-2018/19 academic years.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

SRC and exposure data collected in the NCAA Injury Surveillance Program were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics by sport, event type (practices, competitions), injury mechanism (player contact, surface contact, equipment/apparatus contact), and injury history (new, recurrent). Injury rate ratios (IRRs) were used to examine differential injury rates, and injury proportion ratios (IPRs) were used to examine differential distributions.

RESULTS

A total of 3497 SRCs from 8,474,400 athlete-exposures (AEs) were reported during the study period (4.13 per 10,000 AEs); the competition-related SRC rate was higher than was the practice-related SRC rate (IRR, 4.12; 95% CI, 3.86-4.41). The highest SRC rates were observed in men's ice hockey (7.35 per 10,000 AEs) and women's soccer (7.15 per 10,000 AEs); rates in women's soccer and volleyball increased during 2015/16-2018/19. Player contact was the most prevalently reported mechanism in men's sports (77.0%), whereas equipment/apparatus contact was the most prevalently reported mechanism in women's sports (39.2%). Sex-related differences were observed in soccer, basketball, softball/baseball, and swimming and diving. Most SRCs reported in men's sports (84.3%) and women's sports (81.1%) were reported as new injuries.

CONCLUSION

Given the increasing SRC rates observed in women's soccer and volleyball during the latter years of the study, these results indicate the need to direct further attention toward trajectories of SRC incidence in these sports. The prevalence of equipment/apparatus contact SRCs in women's sports also suggests that SRC mechanisms in women's sports warrant further investigation. As most SRCs during the study period were reported as new injuries, the prevalence of recurrent SRCs in men's and women's ice hockey is also noteworthy.

Systematic review and meta-analysis of sex-based differences for concussion incidence in soccer

OBJECTIVE

To compare concussion incidence in male and female soccer players due to the specific concussion-causing activity.

METHODS/DATA SOURCES

PubMed, EMBASE, and Cochrane Library were searched for studies published between January 2000 and February 2020. Search terms included 'sex,' 'gender,' 'sex differences,' 'brain injury,' 'sports,' 'athletes,' 'incidence,' 'epidemiology,' 'symptoms,' and 'injury rate.' Studies that contained data on concussion incidence in soccer and featured comparisons by sex and soccer activity were included. Studies that were not written in English, contained data on non-sports-related concussions, or were conference abstracts were excluded.

RESULTS

Six studies were included in this meta-analysis, each of which contributed the number of concussions in males and females for a specific soccer activity. Concussion incidence rates were calculated using athlete-exposures as the denominator and a rate ratio was measured by dividing the concussion rate among female soccer players by the rate among male soccer players. Female soccer players were shown to have a greater rate of concussions from heading [1.65 (95% CI: 1.35, 2.03, p < 0.001)] and goalkeeping [1.63 (95% CI: 1.22, 2.17, p = 0.001)]. There were 3 studies comparing sex differences for general play. While the pooled rate ratio was statistically significant [1.51 (95% CI: 1.12, 2.04), p = 0.007], this result was largely driven by 1 study.

CONCLUSION

Concussion incidence rates were significantly higher in female soccer players compared to male players while heading. There is also some evidence to suggest that the incidence is higher for female goalkeepers. Soccer coaches and health care providers need to recognize this sex difference when coaching or treating players.

Sex differences in acute and long-term brain recovery after concussion

Concussion is associated with acute disturbances in brain function and behavior, with potential long‐term effects on brain health. However, it is presently unclear whether there are sex differences in acute and long‐term brain recovery. In this study, magnetic resonance imaging (MRI) was used to scan 61 participants with sport‐related concussion (30 male, 31 female) longitudinally at acute injury, medical clearance to return to play (RTP), and 1‐year post‐RTP. A large cohort of 167 controls (80 male, 87 female) was also imaged. Each MRI session assessed cerebral blood flow (CBF), along with white matter fractional anisotropy (FA) and mean diffusivity (MD). For concussed athletes, the parameters were converted to difference scores relative to matched control subgroups, and partial least squares modeled the main and sex‐specific effects of concussion. Although male and female athletes did not differ in acute symptoms or time to RTP , all MRI measures showed significant sex differences during recovery. Males had greater reductions in occipital‐parietal CBF (mean difference and 95%CI: 9.97 ml/100 g/min, [4.84, 15.12] ml/100 g/min, z = 3.73) and increases in callosal MD (9.07 × 10⁻⁵, [−14.14, −3.60] × 10⁻⁵, z = −3.46), with greatest effects at 1‐year post‐RTP. In contrast, females had greater reductions in FA of the corona radiata (16.50 × 10⁻³, [−22.38, −11.08] × 10⁻³, z = −5.60), with greatest effects at RTP. These findings provide new insights into how the brain recovers after a concussion, showing sex differences in both the acute and chronic phases of injury.

Characteristics of concussion based on patient age and sex: a multicenter prospective observational study

OBJECTIVE

Children with concussion frequently present to emergency departments (EDs). There is limited understanding of the differences in signs, symptoms, and epidemiology of concussion based on patient age. Here, the authors set out to assess the association between age and acute concussion presentations.

METHODS

The authors conducted a multicenter prospective observational study of head injuries at 10 EDs in Australia and New Zealand. They identified children aged 5 to < 18 years, presenting with a Glasgow Coma Scale score of 13-15, presenting < 24 hours postinjury, with no abnormalities on CT if performed, and one or more signs or symptoms of concussion. They extracted demographic, injury-related, and signs and symptoms information and stratified it by age group (5-8, 9-12, 13 to < 18 years).

RESULTS

Of 8857 children aged 5 to < 18 years, 4709 patients met the defined concussion criteria (5-8 years, n = 1546; 9-12 years, n = 1617; 13 to < 18 years, n = 1546). The mean age of the cohort was 10.9 years, and approximately 70% of the patients were male. Sport-related concussion accounted for 43.7% of concussions overall, increasing from 19.1% to 48.9% to 63.0% in the 5-8, 9-12, and 13 to < 18 years age groups. The most common acute symptoms postinjury were headache (64.6%), disorientation (36.2%), amnesia (30.0%), and vomiting (27.2%). Vomiting decreased with increasing age and was observed in 41.7% of the 5-8 years group, 24.7% of the 9-12 years group, and 15.4% of the 13 to < 18 years group, whereas reported loss of consciousness (LOC) increased with increasing age, occurring in 9.6% in the 5-8 years group, 21.0% in the 9-12 years group, 36.7% in the 13 to < 18 years group, and 22.4% in the entire study cohort. Headache, amnesia, and disorientation followed the latter trajectory. Symptom profiles were broadly similar between males and females.

CONCLUSIONS

Concussions presenting to EDs were more sports-related as age increased. Signs and symptoms differed markedly across age groups, with vomiting decreasing and headache, LOC, amnesia, and disorientation increasing with increasing age.

Why are female soccer players experiencing a concussion more often than their male counterparts? A scoping review

BACKGROUND

The risk of concussion is particularly high in female soccer players. There is no consensus as to why female soccer players are at an elevated risk.

OBJECTIVE

To synthesise current evidence investigating reasons for the increased concussion rate in female soccer players.

SOURCES

Searching of six databases (MEDLINE, Scopus, CINAHL, SportDiscus, Web of Science and the Cochrane Library) and grey literature was performed between 13/07/2020-31/07/2020. Keywords were concussion-related terms, terms relating to female football/soccer and terms relating to the mechanism/cause. No constraints were placed on publication date and quantitative or exploratory studies meeting inclusion criteria were eligible. Exclusion criteria were studies not published in English and qualitative studies.

RESULTS

Several hypotheses were identified to explain increased concussion rates in female soccer players, these include, reduced neck strength/anthropometrics, increased head acceleration, increased ball-to-head concussions, differences in hormones and brain structure/function, and reduced visual awareness.

CONCLUSION

Promising ideas/reasons have been identified for increased concussion rates in female soccer players. Despite hypothesis generation there is scarce high-level evidence which is required to guide injury prevention and/or rule changes to protect female soccer players. The level of evidence for included studies is level 2-3 with most being observational cross-sectional or cohort studies.

Removal From Activity After Sports- Related Concussion in Sex-Comparable Sports From the Michigan High School Athletic Association

BACKGROUND

Research has demonstrated that female athletes are more likely to report their sports-related concussion (SRC) symptoms compared with male athletes; however, it is unknown if these reporting behaviors correspond to immediate removal from activity in sex-comparable sports.

PURPOSE

To compare the incidence of high school student-athletes removed and not removed from activity after SRC in sex-comparable sports in Michigan.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Participants included student-athletes diagnosed with SRC participating in Michigan High School Athletic Association-sponsored athletic activities (22 sex-comparable sports) between 2016 and 2019. All SRCs were recorded in the association's Head Injury Reporting System (HIRS) by certified athletic trainers, administrators, or coaches. Removal from activity indicated that the student-athlete was removed from play at the time of an injury event. If the student-athlete reported that his or her suspected injury event occurred earlier during activity or if symptom onset was delayed, "not removed from activity" was entered into the HIRS. Incidence proportions were calculated by dividing SRCs not removed by total SRCs in each sport. Risk ratios were calculated by dividing the incidence proportions of girls not removed by boys not removed in each sport.

RESULTS

A total of 4418 (2773 female, 1645 male) SRCs were reported, with the most occurring in female soccer players (n = 1023). Overall, 515 girls and 243 boys were not removed from activity, resulting in incidences of 0.19 (95% CI, 0.17-0.20) and 0.15 (95% CI, 0.13-0.17), respectively. Across all sports, girls were 1.26 (95% CI, 1.09-1.45) times as likely to not be removed from activity compared with boys. Of the sports with the most SRCs-soccer, basketball, baseball/softball, and lacrosse-girls had 1.37 (95% CI, 1.09-1.72), 1.15 (95% CI, 0.89-1.47), 1.19 (95% CI, 0.77-1.84), and 1.35 (95% CI, 0.94-1.95) times the risk of not being removed, respectively.

CONCLUSION

Girls were at greater risk of not being removed from activity compared with boys in sex-comparable sports. Results from this study should be incorporated into SRC education in Michigan and potentially elsewhere to inform affiliated personnel of potential sex differences and protect female student-athletes from further harm.

Nonsteroidal anti-inflammatory drug use and concussions in adolescent athletes: incidence, severity, and recovery

OBJECTIVE

Given concerns about the potential long-term effects of concussion in young athletes, concussion prevention has become a major focus for amateur sports leagues. Athletes have been known to frequently use anti-inflammatory medications to manage injuries, expedite return to play, and treat concussion symptoms. However, the effects of baseline nonsteroidal anti-inflammatory drug (NSAID) use on the susceptibility to head injury and concussion remain unclear. This study aims to assess the effects of preinjury NSAID use on concussion incidence, severity, and recovery in young athletes.

METHODS

Data from 25,815 ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) tests were obtained through a research agreement with ImPACT Applications Inc. Subjects ranged in age from 12 to 22 years old. Those who reported NSAID use at baseline were assigned to one (anti-inflammatory [AI]) cohort, whereas all others were assigned to the control (CT) cohort. Differences in head trauma and concussion incidence, severity, and recovery were assessed using chi-square tests, unpaired t-tests, and Kaplan-Meier plots.

RESULTS

The CT cohort comprised a higher percentage (p < 0.0001) of males (66.30%) than the AI cohort (44.16%) and had a significantly greater portion of athletes who played football (p = 0.004). However, no statistically significant differences were found between the two cohorts in terms of the incidence of head trauma (CT = 0.489, AI = 0.500, p = 0.9219), concussion incidence (CT = 0.175, AI = 0.169, p = 0.7201), injury severity, or median concussion recovery time (CT = 8, AI = 8, p = 0.6416). In a multivariable analysis controlling for baseline differences between the cohorts, no association was found between NSAID use and concussion incidence or severity.

CONCLUSIONS

In this analysis, the authors found no evidence that preinjury use of NSAIDs affects concussion risk in adolescent athletes. They also found no indication that preinjury NSAID use affects the severity of initial injury presentation or concussion recovery.

Incidence of sports-related concussion in elite para athletes - a 52-week prospective study

Objective: To assess the 52-week incidence proportion and incidence rate of sports-related concussion (SRC) among elite Para athletes, and to analyze the injury mechanisms.Method: In total, 70 male and 37 female Swedish elite Para athletes (median age 29 years) with vision, physical and intellectual impairment, weekly self-reported sports-related injuries including concussion in an eHealth application adapted to Para athletes. Descriptive statistics were used to assess the incidence rate and incidence proportion. Chi-square statistics were used to analyze differences in the proportion of SRC.Results: A total of 13 SRC were reported: three athletes each sustained two SRC. The incidence proportion was 9.3% (95% CI 4.8-16.7), and the incidence rate 0.5 SRC/1000 hours (95% CI 0.3-0.9) of sports exposure. Athletes with vision impairment and female athletes reported a significantly higher proportion of SRC. A majority of the injuries (n = 9; 69%) occurred during sport-specific training. The injury mechanisms were collision with object (n = 7; 54%), collision with person (n = 4; 31%), and poor playing field conditions (n = 2; 16%).Conclusion: The incidence of concussion among elite Paralympic athletes is comparable to sports for able-bodied athletes. Athletes with vision impairment and female athletes reported a significantly higher incidence of SRC, and collisions were the most common injury mechanism. These results can form the basis for future preventive research studies.

Heads Up Play: Acute Assessment and Management of Basketball-Related Craniofacial Injuries by On-Court Personnel

INTRODUCTION

With a following of over 825 million people, basketball currently ranks amongst the world's most popular sports. Despite a number of concussion awareness and player safety protocols that have been implemented at the professional level of organized play, a standardized, layperson-friendly algorithm for the acute management of basketball-related craniofacial injuries does not appear to presently exist.

METHODS

This 10-year retrospective cohort study was conducted using the National Electronic Injury Surveillance System database to examine basketball-related craniofacial injuries from 2010 to 2019. Within the National Electronic Injury Surveillance System dataset, factors including patient age, gender, diagnosis, injury type, and injury location were included in our analysis.

RESULTS

Overall, 22,529 basketball-related craniofacial injuries occurred between 2010 and 2019 in players ages 5 to 49 years old. Adolescent (12-18-year-old) and young adult (19-34-year-old) age groups had the highest incidence of craniofacial injuries. The adolescent cohort experienced a significantly greater proportion of concussions and lower proportion of both facial lacerations and fractures compared with the within group null hypothesis of equal proportions (P < 0.05). The young adult cohort experienced a significantly greater proportion of facial lacerations and fractures and lower proportion of concussions, contusions/abrasions, hematomas, and internal injuries compared to this cohort's null hypothesis (P < 0.05). Males experienced a significantly greater proportion of fractures, lacerations, and dental injuries and lower proportion of concussions, contusions/abrasions, and internal injuries compared to the hypothesized equality of proportions (P < 0.05). Females experienced a significantly greater proportion of concussions, contusions/abrasions, and internal injuries and lower proportion of fractures, lacerations, and dental injuries compared to the hypothesized equality of proportions (P < 0.05).

CONCLUSIONS

Although several steps have already been taken at the professional level to try to promote player safety, particularly with concussion protocols and prevention of lower extremity injuries, there remains a paucity of resources to guide management of other types of acute craniofacial injury. The role of layperson-friendly educational interventions remains intriguing as a potential means of improving outcomes regardless of socioeconomic status or health literacy. Additional studies still need to be completed to determine efficacy and best future direction.

Injury Reduction Programs for Reducing the Incidence of Sport-Related Head and Neck Injuries Including Concussion: A Systematic Review

BACKGROUND

Sport-related head and neck injuries, including concussion, are a growing global public health concern with a need to explore injury risk reduction strategies such as neck exercises.

OBJECTIVES

To systematically review the literature to investigate: (1) the relationship between neck strength and sport-related head and neck injuries (including sport-related concussion (SRC); and (2) whether neck exercise programs can reduce the incidence of (a) sport-related head and neck injuries; and (b) SRC.

METHODS

Five databases (Ovid MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science) and research lists of included studies were searched using a combination of medical subject headings and keywords to locate original studies which reported the association between incidence of head and/or neck injury and neck strength data, or included a neck exercise intervention either in isolation or as part of a more comprehensive exercise program.

RESULTS

From an initial search of 593 studies, six were included in this review. A narrative synthesis was performed due to the heterogeneity of the included studies. The results of two observational studies reported that higher neck strength, but not deep neck flexor endurance, is associated with a lower risk of sustaining a SRC. Four intervention studies demonstrated that injury reduction programs that included neck exercises can reduce the incidence of sport-related head and neck injuries including SRC.

CONCLUSION

Consideration should be given towards incorporating neck exercises into injury reduction exercise programs to reduce the incidence of sport-related head and neck injuries, including SRC.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (registration number: 194217).

Endocrine Responses to Sport-Related Brain Injury in Female Athletes: A Narrative Review and a Call for Action

Sport-related brain injury (SRBI) occurs when a blow to the head causes the brain to move back and forth in the skull, and can lead to neuroendocrine dysfunction. Research has shown that males and females experience and recover from SRBI differently, yet most of what is known regarding diagnosis, treatment, and recovery of SRBI is based on male normative data even though females meet or exceed incidence numbers of SRBIs compared to those of males. Females also have been known to have worse outcomes and a greater number of symptoms following SRBI than males. Research is limited as to why females have worse outcomes, but sex hormones have been suggested as a potential reason. SRBI may cause a dysregulation of the hypothalamic–pituitary–gonadal (HPG) axis, which is responsible for regulating the sex hormones estrogen and progesterone. Initial research has shown that SRBI may suppress estrogen and progesterone, and the concentration of these sex hormones could be indicative of injury severity and recovery trajectory. This review discusses the sex-specific differences in SRBI and also the future direction of research that is needed in order to identify the repercussions of SRBIs for female athletes, which will eventually lead to better clinical treatment, sideline care, and recovery profiles.

MR Elastography demonstrates reduced white matter shear stiffness in early-onset hydrocephalus

INTRODUCTION

Hydrocephalus that develops early in life is often accompanied by developmental delays, headaches and other neurological deficits, which may be associated with changes in brain shear stiffness. However, noninvasive approaches to measuring stiffness are limited. Magnetic Resonance Elastography (MRE) of the brain is a relatively new noninvasive imaging method that provides quantitative measures of brain tissue stiffness. Herein, we aimed to use MRE to assess brain stiffness in hydrocephalus patients compared to healthy controls, and to assess its associations with ventricular size, as well as demographic, shunt-related and clinical outcome measures.

METHODS

MRE was collected at two imaging sites in 39 hydrocephalus patients and 33 healthy controls, along with demographic, shunt-related, and clinical outcome measures including headache and quality of life indices. Brain stiffness was quantified for whole brain, global white matter (WM), and lobar WM stiffness. Group differences in brain stiffness between patients and controls were compared using two-sample t-tests and multivariable linear regression to adjust for age, sex, and ventricular volume. Among patients, multivariable linear or logistic regression was used to assess which factors (age, sex, ventricular volume, age at first shunt, number of shunt revisions) were associated with brain stiffness and whether brain stiffness predicts clinical outcomes (quality of life, headache and depression).

RESULTS

Brain stiffness was significantly reduced in patients compared to controls, both unadjusted (p ≤ 0.002) and adjusted (p ≤ 0.03) for covariates. Among hydrocephalic patients, lower stiffness was associated with older age in temporal and parietal WM and whole brain (WB) (beta (SE): -7.6 (2.5), p = 0.004; -9.5 (2.2), p = 0.0002; -3.7 (1.8), p = 0.046), being female in global and frontal WM and WB (beta (SE): -75.6 (25.5), p = 0.01; -66.0 (32.4), p = 0.05; -73.2 (25.3), p = 0.01), larger ventricular volume in global, and occipital WM (beta (SE): -11.5 (3.4), p = 0.002; -18.9 (5.4), p = 0.0014). Lower brain stiffness also predicted worse quality of life and a higher likelihood of depression, controlling for all other factors.

CONCLUSIONS

Brain stiffness is reduced in hydrocephalus patients compared to healthy controls, and is associated with clinically-relevant functional outcome measures. MRE may emerge as a clinically-relevant biomarker to assess the neuropathological effects of hydrocephalus and shunting, and may be useful in evaluating the effects of therapeutic alternatives, or as a supplement, of shunting.

A Promising Subject-Level Classification Model for Acute Concussion Based on Cerebrovascular Reactivity Metrics

Concussion imaging research has primarily focused on neuronal disruption with lesser emphasis directed toward vascular dysfunction. However, blood flow metrics may be more sensitive than measures of neuronal integrity. Vascular dysfunction can be assessed by measuring cerebrovascular reactivity (CVR)-the change in cerebral blood flow per unit change in vasodilatory stimulus. CVR metrics, including speed and magnitude of flow responses to a standardized well-controlled vasoactive stimulus, are potentially useful for assessing individual subjects following concussion given that blood flow dysregulation is known to occur with traumatic brain injury. We assessed changes in CVR metrics to a standardized vasodilatory stimulus during the acute phase of concussion. Using a case control design, 20 concussed participants and 20 healthy controls (HCs) underwent CVR assessment measuring blood oxygen-level dependent (BOLD) magnetic resonance imaging using precise changes in end-tidal partial pressure of CO₂ (PETCO₂). Metrics were calculated for the whole brain, gray matter (GM), and white matter (WM) using sex-stratification. A leave-one-out receiver operating characteristic (ROC) analysis classified concussed from HCs based on CVR metrics. CVR magnitude was greater and speed of response faster in concussed participants relative to HCs, with WM showing higher classification accuracy compared with GM. ROC analysis for WM-CVR metrics revealed an area under the curve of 0.94 in males and 0.90 in females for speed and magnitude of response respectively. These greater than normal responses to a vasodilatory stimulus warrant further investigation to compare the predictive ability of CVR metrics against structural injury metrics for diagnosis and prognosis in acute concussion.

Clinical features and sex differences in pediatric post-traumatic headache: A retrospective chart review at a Boston area concussion clinic

BACKGROUND

Often concussion/mTBI triggers a chronic headache syndrome called persistent post-traumatic headache (P-PTH) that can last from months to years post-injury, and produce significant disruption of childhood education, social interaction and development. Although prevalent and highly disabling, P-PTH is underrepresented in headache and pain research and lacks clear definition and pathophysiology. Clinical presentation of P-PTH frequently resembles that of other headache disorders, like migraine, yet the pathophysiological mechanisms are distinct and not fully understood, making the disorder difficult to treat in the clinical setting.

METHODS

In a retrospective analysis of 1506 pediatric patients attending Boston Children's Hospital clinics, demographic trends, symptom features, and the influence of sex on clinical presentation of PTH are presented. We compare clinical characteristics of P-PTH with a published cohort of migraine patients to evaluate the clinical features that are unique to P-PTH.

RESULTS

Findings show that despite equivalent representation of sex in the clinic, P-PTH is expressed more in females than males and is weighted towards somatic symptoms. Relative to migraine, PTH is less associated with a family history of headache.

CONCLUSIONS

The ability to identify persons with PTH can help manage risk factors and identify persons likely to develop persistent post-concussion symptoms.