Sport Concussion and the Female Athlete

Access to athletic trainers and sex as modifiers of time to reach clinical milestones after sport-related concussion in collegiate athletes

OBJECTIVE

Investigate whether an athlete's biological sex and exposure to a dedicated athletic trainer (AT) were related to clinical milestones after a sports-related concussion (SRC).

DESIGN

Retrospective chart review.

METHODS

Medical charts of collegiate athletes (n = 196 [70.9% female]) diagnosed with SRC were reviewed to extract: biological sex, dedicated AT exposure for their sport (yes/no), and time (days) to reaching clinical milestones (diagnosis, symptom resolution, unrestricted return to sport [RTS]). Mann-Whitney U tests were used to determine whether time to clinical milestones differed by sex, AT exposure, or their interaction. Proportions of same-day diagnoses and times to diagnosis, symptom resolution, and unrestricted RTS were evaluated with chi-squared and spearman's rank correlations, respectively.

RESULTS

There were no significant differences in times to reaching any clinical milestone by sex, AT exposure, or their interaction (ps > 0.05). Forty-three percent of participants were diagnosed on the day of their SRC. This did not differ by sex or AT exposure (ps > 0.29). Longer times to SRC diagnosis were associated with more days to symptom resolution (ρ = 0.236, p = 0.001) and unrestricted RTS (ρ = 0.223, p < 0.001).

CONCLUSIONS

Athlete sex and AT exposure were not associated with times to reach any clinical milestone; however, delayed diagnosis was associated with longer times to reach clinical recovery.

Female Collegiate Athletes' Concussion Characteristics and Recovery Patterns: A Report from the NCAA-DoD CARE Consortium

Concussion has been described in the United States (US) collegiate student-athlete population, but female-specific findings are often underrepresented and underreported. Our study aimed to describe female collegiate student-athletes' initial injury characteristics and return to activity outcomes following concussion. Female collegiate student-athletes (n = 1393) from 30-US institutions experienced a concussion and completed standardized, multimodal concussion assessments from pre-injury through unrestricted return to play (uRTP) in this prospective, longitudinal cohort study. Initial injury presentation characteristics, assessment, and return to activity outcomes [<48-h (acute), return to learn, initiate return to play (iRTP), uRTP] were collected. We used descriptive statistics to report injury characteristics, return to activity outcomes, and post-injury assessment performance change categorization (worsened, unchanged, improved) based on change score confidence rank criteria across sport contact classifications [contact (n = 661), limited (n = 446), non-contact (n = 286)]. The median (25th to 75th percentile) days to return to learn was 6.0 (3.0-10.0), iRTP was 8.1 (4.8-13.8), and uRTP was 14.8 (9.9-24.0), but varied by contact classification. Across contact levels, the majority experienced worse SCAT total symptom severity (72.8-82.6%), ImPACT reaction time (91.2-92.6%), and BSI-18 total score (45.2-51.8%) acutely relative to baseline, but unchanged BESS total errors (58.0-60.9%), SAC total score (71.5-76.1%), and remaining ImPACT domains (50.6-66.5%). Our findings provide robust estimates of the typical female collegiate student-athlete presentation and recovery trajectory following concussion, with overall similar findings to the limited female collegiate student-athlete literature. Overall varying confidence rank classification was observed acutely. Our findings provide clinically-relevant insights for athletes, clinicians, researchers, and policymakers to inform efforts specific to females experiencing concussion.

Initial Mild Traumatic Brain Injury Characteristics and Recovery Patterns Among Females Across the United States Military Service Academies: A Report from the NCAA-DoD CARE Consortium

Mild traumatic brain injury (mTBI) has been described in the United States (US) military service academy cadet population, but female-specific characteristics and recovery outcomes are poorly characterized despite sex being a confounder. Our objective was to describe female cadets' initial characteristics, assessment performance, and return-to-activity outcomes post-mTBI. Female cadets (n = 472) from the four US military service academies who experienced a mTBI completed standardized mTBI assessments from pre-injury to acute initial injury and unrestricted return-to-duty (uRTD). Initial injury presentation characteristics (e.g., delayed symptoms, retrograde amnesia) and return-to-activity outcomes [i.e., return-to-learn, initiate return-to-duty protocol (iRTD), uRTD] were documented. Descriptive statistics summarized female cadets' injury characteristics, return-to-activity outcomes, and post-mTBI assessment performance change categorization (worsened, unchanged, improved) relative to pre-injury baseline using established change score confidence rank criteria for each assessment score. The median (interquartile range) days to return-to-learn (n = 157) was 7.0 (3.0-14.0), to iRTD (n = 412) was 14.7 (8.6-25.8), and to uRTD (n = 431) was 26.0 (17.7-41.8). The majority experienced worse SCAT total symptom severity (77.8%) and ImPACT reaction time (97.0%) acutely < 24-h versus baseline, but unchanged BESS total errors (75.2%), SAC total score (72%), BSI-18 total score (69.6%), and ImPACT verbal memory (62.3%), visual memory (58.4%), and visual motor speed (52.5%). We observed similar return-to-activity times in the present female cadet cohort relative to the existing female-specific literature. Confidence ranks categorizing post-mTBI performance were heterogenous and indicate multimodal assessments are necessary. Our findings provide clinically relevant insights to female cadets experiencing mTBI across the US service academies for stakeholders providing healthcare.

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.

Sex differences in college students' knowledge of concussion and concussion education sources

Aim

To understand sex differences and sources of concussion education for college students. The literature for college students primarily focuses on sports concussions and general knowledge. Understanding how non-students-athletes learn is critical to developing interventions to improve concussion knowledge.

Participants

A random sample of 208 students from four-year institutions.

Methods

A 22-question online survey explored postsecondary students' current knowledge and education regarding concussions.

Results

Findings indicated that sex differences emerged with concussion knowledge and sources of concussion knowledge (e.g., leaflets, pamphlets, parents, and television). The top choices for where they wanted to learn about concussions were health educators, health centers, and campus peer educators.

Conclusion

This study provides an initial evaluation and implications for future research on providing concussion education.

Premorbid Risk Factors and Acute Injury Characteristics of Sport-Related Concussion Across the National Collegiate Athletic Association: Findings from the Concussion Assessment, Research, and Education (CARE) Consortium

BACKGROUND

Previous sport-related concussion research highlights post-injury characteristics that influence recovery trajectories; however, there is limited information regarding premorbid factors that affect sport-related concussion risk.

OBJECTIVE

We aimed to (a) compare premorbid demographic factors among a large cohort of collegiate student athletes who did or did not sustain a sport-related concussion and (b) assess differences in acute injury characteristics based on biological sex and contact level.

METHODS

We conducted a cohort study of university student athletes from 22 sports enrolled in the Concussion Assessment, Research, and Education (CARE) Consortium study from 2014 to 2021 (n = 1804 student athletes with sport-related concussions; n = 21,702 student athletes without sport-related concussions).

RESULTS

Statistical analyses indicated student athletes who self-identified as Black (odds ratio [OR] = 1.61; 95% confidence interval [CI] = 1.42, 1.81) or multiracial (OR = 1.32; 95% CI 1.10, 1.59) demonstrated greater odds of experiencing sport-related concussions than White-identifying student athletes. Additional findings suggest male athletes (OR = 1.47; 95% CI 1.20, 1.81) and contact sport student athletes (OR = 1.40; 95% CI 1.16, 1.70) may be at increased odds for sport-related concussions if they were previously diagnosed with attention deficit hyperactive disorder. Notable post-injury characteristics across sexes included differences in the incident loss of consciousness (male: 5.9%, female: 2.6%; p < 0.001), post-traumatic amnesia (male: 13.6%, female: 5.1%; p < 0.001), and retrograde amnesia (male: 6.8%, female: 2.8%; p < 0.001). A greater proportion of contact-sport student athletes experienced an altered mental status (52.7%) than limited contact (36.2%) and non-contact (48.6%) [p < 0.001]. Last, student athletes participating at lower contact levels were more likely to have a longer delay in removal from activity following injury (contact: 73.6 ± 322.2 min; limited contact: 139.1 ± 560.0 min; non-contact: 461.4 ± 1870.8 min; p = 0.005).

CONCLUSIONS

The present study provides contemporary pre- and post-sport-related concussion injury characteristics using a considerably sized cohort of collegiate student athletes. These findings support previous work suggesting sport-related concussion results in complex individualized clinical presentations, which may influence management strategies.

Gender Specificities in Sleep Disturbances following Mild Traumatic Brain Injury: A Preliminary Study

Mild traumatic brain injury (mTBI), or concussion, can lead to persistent cognitive and functional symptoms that impede quality of life to a varying extent. This condition is referred to as post-concussive syndrome (PCS). Sleep disturbances are part of it but their distribution among different genders remains scarcely investigated. This pilot cross-sectional anonymous web-based survey interviewed volunteer 18-55 years old participants with a recent (i.e., less than 5 years) reported history of mTBI. Questionnaires related to persistent post-concussive symptoms (PPCS; Rivermead post-concussion symptoms questionnaire), sleep quality (Pittsburgh Sleep Quality Index) and daytime sleepiness (Epworth Sleepiness Scale) were administered as part of the survey. Ninety-one participants' responses were analysed (61 female; 30 male); 43% of them suffered from post-concussive syndrome, 60% reported poor sleep quality and 34% experienced excessive daytime sleepiness. The proportion of PPCS was significantly higher in female participants as compared to males (female: 57%; male: 13%; Fisher's exact test p < 0.001). Excessive daytime sleepiness was also significantly more present in females (female: 44%; male: 13%; p < 0.001) whereas poor sleep quality was present in similar proportions between females and males (female: 66%; male: 50%; p = 0.176). Even though based on a relatively small sample, these findings highlight important gender differences that should be accounted for in PPCS medical care and management.

Sports-Related Concussion Is a Personalized Issue—Evaluation of Medical Assessment and Subjective Feeling of the Athlete in a German Level 1 Trauma Center

Sports-related concussions (SRC) have developed into a highly discussed topic in sports medicine over the last few years and demonstrate a severe issue in the personalized treatment of patients. This retrospective cohort study investigated 86 patients with sports-related concussions in a level 1 trauma center, relating to the mechanism, symptoms, medical history, acute therapy including first assessment and the return to sport. The research is based on medical records as well as questionnaires six months after hospitalization. Loss of consciousness for under 30 min (41.2%), headache (36.5%) and amnesia (29.4%) were the most frequent symptoms when presenting in the emergency room. During the hospitalization, mainly headache and vertigo were documented. Most concussions occurred after incidents in equitation and cycling sports; the most common mechanism was falling to the ground with a subsequent impact (59.3%). At the time of discharge from hospital, in 13.4% of all cases, concussion symptoms were still documented in medical records, in contrast to 39.5% of the concerned athletes who reported symptoms for longer than 24 h, and 41.0% who reported ongoing post-concussion symptoms after six months. Concussions are difficult-to-treat disorders with a challenging diagnostic process and many symptoms in various values and levels of persistence. Therefore, a patient-involving treatment with a complaint-dependent return to sport process should be applied to concerned athletes.

Under-representation of female athletes in research informing influential concussion consensus and position statements: an evidence review and synthesis

OBJECTIVE

We aimed to quantify the female athlete composition of the research data informing the most influential consensus and position statements in treating sports-related concussions.

DESIGN

We identified the most influential concussion consensus and position statements through citation and documented clinician use; then, we analysed the percentage of male and female athletes from each statement's cited research.

DATA SOURCES

We searched PubMed on 26 August 2021 with no date restrictions for English language studies using the terms 'concussion position statement' and 'concussion consensus statement.'

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Based on each statement having multiple statement editions, documented clinician use, and substantial citation advantages, we selected the National Athletic Trainers' Association (NATA, 2014), International Conference on Concussion in Sport (ICCS, 2017) and the American Medical Society for Sports Medicine (AMSSM, 2019). We extracted all cited studies from all three papers for assessment. For each paper analysing human data, at least two authors independently recorded female athlete participant data.

RESULTS

A total of 171 distinct studies with human participants were cited by these three consensus and position papers and included in the female athlete analyses (93 NATA; 13 ICCS; 65 AMSSM). All three statements documented a significant under-representation of female athletes in their cited literature, relying on samples that were overall 80.1% male (NATA: 79.9%, ICCS: 87.8 %, AMSSM: 79.4%). Moreover, 40.4% of these studies include no female participants at all.

CONCLUSION

Female athletes are significantly under-represented in the studies guiding clinical care for sport-related concussion for a broad array of sports and exercise medicine clinicians. We recommend intentional recruitment and funding of gender diverse participants in concussion studies, suggest authorship teams reflect diverse perspectives, and encourage consensus statements note when cited data under-represent non-male athletes.

Utility of VOMS, SCAT3, and ImPACT Baseline Evaluations for Acute Concussion Identification in Collegiate Athletes: Findings From the NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium

BACKGROUND

The Vestibular/Ocular-Motor Screening (VOMS) is a valuable component of acute (<72 hours) sports-related concussion (SRC) assessments and is increasingly used with the Immediate Post-concussion Assessment and Cognitive Testing (ImPACT) instrument and the third edition of the Sport Concussion Assessment Tool (SCAT3). Research has suggested that VOMS acute postinjury scores are useful in identifying acute concussion. However, the utility of preseason baseline measurements to improve diagnostic accuracy remains ambiguous. To this end, there is a need to determine how reliable VOMS baseline assessments are across years and whether incorporating individuals' baseline performance improves diagnostic yield for acute concussions.

PURPOSE

To analyze VOMS, SCAT3, and ImPACT to evaluate the test-retest reliability of consecutive-year preseason baseline assessments to directly compare the diagnostic utility of these tools when incorporating baseline assessments versus using postinjury data alone to identify acute SRC.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Preseason and postinjury VOMS, SCAT3, ImPACT Post-Concussion Symptom Scale (PCSS), and ImPACT composite scores were analyzed for 3958 preseason (47.7% female) and 496 acute (≤48 hours) SRC (37.5% female) collegiate athlete evaluations in the National Collegiate Athletic Association-Department of Defense Concussion Assessment Research and Education Consortium. Descriptive statistics, Kolmogorov-Smirnov significance, and Cohen d effect size were calculated. Consecutive-year baseline reliability was evaluated for a subset of 447 athlete encounters using Pearson r, Cohen κ, Cohen d, and 2-way mixed intraclass correlation coefficients (ICCs). Wilcoxon signed rank tests were used to determine the statistical significance between population performances, and the 90% reliable change index (RCI) was calculated from the test-retest results. Preseason to postinjury change scores were then calculated from each tool's RCI. Finally, receiver operating characteristic (ROC) curve analyses were conducted, and DeLong method was used to compare the area under the curve (AUC) of raw postinjury scores versus change scores from preseason baseline assessments. Potential effects of sex, medical history (learning disorders or attention-deficit/hyperactivity disorder), and outlier data were also explored.

RESULTS

Effect sizes were large, and overall predictive utilities were clinically useful for postinjury VOMS Total (d = 2.44; AUC = 0.85), the SCAT3 Symptom Evaluation total severity score (d = 1.74; AUC = 0.82), and the ImPACT PCSS total severity score (d = 1.67; AUC = 0.80). Comparatively, effect sizes were small and predictive utilities were poor for Standardized Assessment of Concussion (SAC), modified Balance Error Scoring System (mBESS), and all ImPACT composites (d = 0.11-0.46; AUC = 0.48-0.59). Preseason baseline test-retest reliability was poor to moderate (r = 0.23-0.52; κ = 0.32-0.36; ICC = 0.36-0.68) for all assessments except ImPACT Visual Motion Sensitivity (r = 0.73; ICC = 0.85). Incorporating baseline scores for VOMS Total, SCAT3 (Symptom Evaluation, SAC, mBESS), ImPACT PCSS, or ImPACT composites did not significantly improve AUCs.

CONCLUSION

VOMS Total and symptom severity (SCAT3, PCSS) total scores had large effect sizes and clinically useful AUCs for identifying acute concussion. However, all tools demonstrated high within-patient test-retest variability, resulting in poor reliability. The findings in this sample of collegiate athletes suggest that incorporating baseline assessments does not significantly increase diagnostic yield for acute concussion.

Head Impact Research Using Inertial Sensors in Sport: A Systematic Review of Methods, Demographics, and Factors Contributing to Exposure

BACKGROUND

The number and magnitude of head impacts have been assessed in-vivo using inertial sensors to characterise the exposure in various sports and to help understand their potential relationship to concussion.

OBJECTIVES

We aimed to provide a comprehensive review of the field of in-vivo sensor acceleration event research in sports via the summary of data collection and processing methods, population demographics and factors contributing to an athlete's exposure to sensor acceleration events.

METHODS

The systematic search resulted in 185 cohort or cross-sectional studies that recorded sensor acceleration events in-vivo during sport participation.

RESULTS

Approximately 5800 participants were studied in 20 sports using 18 devices that included instrumented helmets, headbands, skin patches, mouthguards and earplugs. Female and youth participants were under-represented and ambiguous results were reported for these populations. The number and magnitude of sensor acceleration events were affected by a variety of contributing factors, suggesting sport-specific analyses are needed. For collision sports, being male, being older, and playing in a game (as opposed to a practice), all contributed to being exposed to more sensor acceleration events.

DISCUSSION

Several issues were identified across the various sensor technologies, and efforts should focus on harmonising research methods and improving the accuracy of kinematic measurements and impact classification. While the research is more mature for high-school and collegiate male American football players, it is still in its early stages in many other sports and for female and youth populations. The information reported in the summarised work has improved our understanding of the exposure to sport-related head impacts and has enabled the development of prevention strategies, such as rule changes.

CONCLUSIONS

Head impact research can help improve our understanding of the acute and chronic effects of head impacts on neurological impairments and brain injury. The field is still growing in many sports, but technological improvements and standardisation of processes are needed.

Sex Differences and Reporting of SCAT-5 Concussion Symptoms in Adolescent Athletes

OBJECTIVE

To elucidate specific symptoms that may differ between adolescent female and male athletes after a sports-related concussion (SRC) and identify symptoms that may require greater clinical attention by medical and athletic staff.

DESIGN

Prospective.

SETTING

This study is part of a larger research project conducted at clinics in the North Texas Concussion Network (ConTex) Registry.

PARTICIPANTS

Subjects (N = 491) aged 12 to 18 years who sustained a diagnosed SRC within 30 days of clinic visit.

INDEPENDENT VARIABLES

Sex (female vs male). Covariates included age, race, current mood (anxiety and depression), learning disability/ADHD, and time to clinic.

MAIN OUTCOME MEASURES

Twenty-two individual postconcussion symptoms as measured by the Post-Concussion Symptom Scale from the Sport Concussion Assessment Tool-5 (SCAT-5).

RESULTS

Girls endorsed higher levels of anxiety and depression symptoms at initial clinic visit. analysis of covariance results revealed that girls had significantly greater symptom severity of headache, dizziness, sensitivity to light, sensitivity to noise, pressure in the head, feeling slowed down, fatigue, and drowsiness than boys. Ordinal logistic regression results also revealed that girls had significantly greater predicted odds of higher symptom severity on these 8 symptoms and in trouble concentrating than boys.

CONCLUSIONS

Closer examination of specific symptoms with attention to patients' current levels of anxiety and depression symptoms may better inform medical and athletic staff to anticipate and address symptoms that may present greater challenges for adolescent girls than boys.

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.

Sports-related concussions in high school females: an epidemiologic analysis of twenty-year national trends

The epidemiology of sports-related concussions (SRCs) and closed head injuries (CHIs) in high school females remains undefined at the national level, especially for unorganized sports and recreational activities. This study examines 1,176,092 national weighted estimates of SRCs or CHIs in female patients 14-18 years of age presenting to United States (US) emergency departments (EDs) between 2000 and 2019 in the National Electronic Injury Surveillance System (NEISS). The national weighted estimate of female patients in our study increased significantly (p < 0.001) between 2000 (9,835; 95% Confidence Interval [CI] 7,105-12,566) and 2019 (31,751; CI 26,392-37,110). The top five ranked sports and recreational activities most commonly associated with concussions and CHIs in female patients 14-18 years of age were: soccer (20.6%; CI 17.6%-23.6%); basketball (18.5%; CI 16.9%-20.1%); cheerleading (10.4%; CI 8.9%-11.9%); softball (10.1%; CI 9.0%-11.3%); volleyball (6.5%; CI 5.7%-7.2%). Simple univariate regression models showed that an increase of 10,000 annual female participants across all high school sports and recreational activities was associated with 308.7 (SE = 20.8, p < 0.001, R2 = 0.92) additional annual SRCs and CHIs presenting to US EDs. The promotion of concussion awareness and educational programs may help minimize SRCs and CHIs.

Prevalence and mechanisms of injuries in water polo: a systematic review

Objective

To summarise the information available in the literature on the prevalence of injuries in water polo and injury risk factors.

Methods

Protocol was registered on Open Science Framework. MEDLINE, CINAHL, Embase and SPORTDiscus databases were searched for keywords relating to water polo and injuries on 3 February 2021. References were searched for additional studies. Only original research papers in English or French were included, and studies without an injured group were excluded. A data extraction file was made based on the Cochrane Collaboration recommendations. Study quality was evaluated with the Newcastle-Ottawa scales for cohorts and a modified version for cross-sectional studies.

Results

The initial search yielded 581 articles, with 5 more added from reference lists, but only 41 remained after removing duplicates and applying inclusion/exclusion criteria. Thirty-one articles identified the head, fingers and shoulders as the most common sites of injury. Ten articles on mechanism of injury focused mainly on the shoulder, with degenerative changes, posture, scapular alignment, strength, flexibility and overhead shooting kinematics as the main injury risk factors. Publication types included cohort studies, cross-sectional studies, and one case series.

Conclusions

Most traumatic injuries affect the hands and the head from unexpected contact with the ball or opponents. Conversely, training injuries seem to affect mainly the shoulder area. Low level evidence suggests a correlation between shoulder injuries and lack of strength or flexibility as well as large volumes of overhead throwing. Further prospective research is needed to investigate risk factors for other body areas.

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.

Dual-Task Gait Recovery after Concussion among Female and Male Collegiate Athletes

PURPOSE

Few studies have investigated recovery between sexes using objective outcome measures. Our purpose was to examine the independent association between biological sex and recovery of postconcussion gait among collegiate athletes.

METHODS

We evaluated participants with a diagnosed concussion <7 d postinjury, and approximately 1.5 months and 3.5 months postinjury. Participants completed a single/dual-task gait evaluation and symptom inventory. During dual-task trials, they completed a mental task (backward subtraction, spelling, or month recitation). The primary outcome measure was height-adjusted gait velocity recovery, defined as achieving normal gait velocity using established values: >0.56 and >0.50 gait velocity (m·s)/height (m) under single and dual-task conditions, respectively. We used a multivariable Cox proportional hazard model to identify associations between sex and dual-task recovery, controlling for age, concussion history, symptom severity, and loss of consciousness at the time of injury.

RESULTS

Ninety-four individuals participated in the study: 47 (50%) were female athletes (mean age = 20.1, SD = 1.3 yr) and 47 (50%) were male athletes (mean age = 20.3, SD = 1.3 yr). Sex was not independently associated with height-adjusted single-task gait velocity recovery after controlling for potential confounders (hazard ratio = 1.62, 95% confidence interval = 0.87-3.01). However, male sex was independently associated with longer dual-task gait recovery time after controlling for potential confounders (hazard ratio = 2.43, 95% confidence interval = 1.11-5.35).

CONCLUSION

Male athletes required a longer duration of time after concussion to achieve dual-task gait recovery than female athletes. Thus, functional dual-task abilities after concussion may be affected differentially by sex and should be accounted for within individualized concussion management strategies.

Sex Differences in Behavioral Sensitivities After Traumatic Brain Injury

Traumatic brain injury (TBI) is associated with high rates of post-injury psychiatric and neurological comorbidities. TBI is more common in males than females despite females reporting more symptoms and longer recovery following TBI and concussion. Both pain and mental health conditions like anxiety and post-traumatic stress disorder (PTSD) are more common in women in the general population, however the dimorphic comorbidity in the TBI population is not well-understood. TBI may predispose the development of maladaptive anxiety or PTSD following a traumatic stressor, and the impact of sex on this interaction has not been investigated. We have shown that white noise is noxious to male rats following fluid percussion injury (FPI) and increases fear learning when used in auditory fear conditioning, but it is unclear whether females exhibit a similar phenotype. Adult female and male rats received either lateral FPI or sham surgery and 48 h later received behavioral training. We first investigated sex differences in response to 75 dB white noise followed by white noise-signaled fear conditioning. FPI groups exhibited defensive behavior to the white noise, which was significantly more robust in females, suggesting FPI increased auditory sensitivity. In another experiment, we asked how FPI affects contextual fear learning in females and males following unsignaled footshocks of either strong (0.9 mA) or weaker (0.5 mA) intensity. We saw that FPI led to rapid acquisition of contextual fear compared to sham. A consistent pattern of increased contextual fear after TBI was apparent in both sexes across experiments under differing conditioning protocols. Using a light gradient open field task we found that FPI females showed a defensive photophobia response to light, a novel finding supporting TBI enhanced sensory sensitivity across modalities in females. General behavioral differences among our measures were observed between sexes and discussed with respect to interpretations of TBI effects for each sex. Together our data support enhanced fear following a traumatic stressor after TBI in both sexes, where females show greater sensitivity to sensory stimuli across multiple modalities. These data demonstrate sex differences in emergent defensive phenotypes following TBI that may contribute to comorbid PTSD, anxiety, and other neurological comorbidities.

The influence of fatiguing exercise on Sport Concussion Assessment Tool (SCAT) scoring in a female pediatric population

There is currently a lack of information available about the effect that exercise fatigue may have on Child Sport Concussion Assessment Tool (SCAT) scoring in a pediatric population. Objective: The goal of this study was to examine the influence of a fatiguing bout of aerobic exercise on Child Sport Concussion Assessment Tool (SCAT) scoring in an adolescent female sporting population. Methods: A prospective, observational-based, test-retest study design was used to collect Child SCAT data from thirty healthy 9-12 year old physically active females during two testing sessions that occurred a minimum of 7 days apart. Within each testing session, each child completed a fatiguing bout of aerobic exercise, and the Child SCAT was administered: (1). Pre-exercise and (2). Post-exercise. Parametric and non-parametric testing was used to compare aerobic exercise test results and pre- vs. post-exercise Child SCAT data. Test-retest reliability was evaluated using intra-class correlation coefficient (ICC 3,1) analysis. Results: No significantly differences were noted between pre- and post-exercise Child SCAT data during either test day. ICC values suggested that a majority of the individual components of the Child SCAT demonstrated poor test-retest reliability. Conclusion: Clinicians using the Child SCAT as a sideline assessment tool during youth sport should have confidence that individual component scores are uninfluenced by aerobic exercise completed immediately prior to assessment. But, clinicians should also be cautioned against using Child SCAT data from consecutive testing days when making decisions about patient recovery and return-to-sport timelines.

Serum Protein Biomarker Findings Reflective of Oxidative Stress and Vascular Abnormalities in Male, but Not Female, Collision Sport Athletes

Studies have indicated that concussive and sub-concussive brain injuries that are frequent during collision sports may lead to long-term neurological abnormalities, however there is a knowledge gap on how biological sex modifies outcomes. Blood-based biomarkers can help to identify the molecular pathology induced by brain injuries and to better understand how biological sex affects the molecular changes. We therefore analyzed serum protein biomarkers in male (n = 50) and female (n = 33) amateur Australian rules footballers (i.e., Australia's most participated collision sport), both with a history of concussion (HoC) and without a history of concussion (NoHoC). These profiles were compared to those of age-matched control male (n = 24) and female (n = 20) athletes with no history of neurotrauma or participation in collision sports. Serum levels of protein markers indicative of neuronal, axonal and glial injury (UCH-L1, NfL, tau, p-tau, GFAP, BLBP, PEA15), metabolic (4-HNE) and vascular changes (VEGF-A, vWF, CLDN5), and inflammation (HMGB1) were assessed using reverse phase protein microarrays. Male, but not female, footballers had increased serum levels of VEGF-A compared to controls regardless of concussion history. In addition, only male footballers who had HoC had increased serum levels of 4-HNE. These findings being restricted to males may be related to shorter collision sport career lengths for females compared to males. In summary, these findings show that male Australian rules footballers have elevated levels of serum biomarkers indicative of vascular abnormalities (VEGF-A) and oxidative stress (4-HNE) in comparison to non-collision control athletes. While future studies are required to determine how these findings relate to neurological function, serum levels of VEGF-A and 4-HNE may be useful to monitor subclinical neurological injury in males participating in collision sports.

Soccer-related head injuries-analysis of sentinel surveillance data collected by the electronic Canadian Hospitals Injury Reporting and Prevention Program

Background

Participating in sports is a great way to gain physical, psychological, and social benefits. However, it also carries the risk of injury. Soccer is one of the most popular sports worldwide, and in recent years, there have been concerns about potential vulnerabilities to head injuries.

Objectives

To investigate soccer-related head injuries (SRHIs), using data from the electronic Canadian Hospitals Injury Reporting and Prevention Program (eCHIRPP) surveillance system. Specifically, we aim to compare characteristics of SRHI cases to all head injury cases within the eCHIRPP database.

Methods

Descriptive analyses of emergency department (ED) injury surveillance data (2011 to 2017) for individuals aged 5 to 29 years from all participating eCHIRPP sites. Computation of proportionate injury ratios (PIR) comparing SRHIs to all head injuries reported to eCHIRPP, and 95% confidence intervals (CI).

Results

A total of 3,970 SRHIs were reported to eCHIRPP. Injuries were from contact with another player, the ball, ground, goal-post, and other causes. Of the injuries caused by contact with the ball, 9% were from purposely directing the ball with the head (heading). A higher proportion of concussions (PIR=1.32, 95% confidence interval [CI]: 1.27 to 1.37) and minor closed head injuries (PIR=1.20, 95% CI: 1.15 to 1.26) were observed in soccer players. Higher proportions of head injuries occurred in organized soccer and soccer played outdoors. However, admission to the ED for a SRHI was rare (PIR=0.40, 95% CI: 0.30 to 0.55).

Conclusions

Overall, elevated proportions of brain injuries were observed among soccer players, however, these injuries were unlikely to result in a hospital admission. Moreover, purposely heading the ball contributed to few ED visits.

The Effect of Muscle Activation on Head Kinematics During Non-injurious Head Impacts in Human Subjects

In this study, twenty volunteers were subjected to three, non-injurious lateral head impacts delivered by a 3.7 kg padded impactor at 2 m/s at varying levels of muscle activation (passive, co-contraction, and unilateral contraction). Electromyography was used to quantify muscle activation conditions, and resulting head kinematics were recorded using a custom-fit instrumented mouthpiece. A multi-modal battery of diagnostic tests (evaluated using neurocognitive, balance, symptomatic, and neuroimaging based assessments) was performed on each subject pre- and post-impact. The passive muscle condition resulted in the largest resultant head linear acceleration (12.1 ± 1.8 g) and angular velocity (7.3 ± 0.5 rad/s). Compared to the passive activation, increasing muscle activation decreased both peak resultant linear acceleration and angular velocity in the co-contracted (12.1 ± 1.5 g, 6.8 ± 0.7 rad/s) case and significantly decreased in the unilateral contraction (10.7 ± 1.7 g, 6.5 ± 0.7 rad/s) case. The duration of angular velocity was decreased with an increase in neck muscle activation. No diagnostic metric showed a statistically or clinically significant alteration between baseline and post-impact assessments, confirming these impacts were non-injurious. This study demonstrated that isometric neck muscle activation prior to impact can reduce resulting head kinematics. This study also provides the data necessary to validate computational models of head impact.

Sport-Related Concussion in Female Athletes: A Systematic Review

Background:

Female athletes are more susceptible to sport-related concussions (SRCs) and experience worse outcomes compared with male athletes. Although numerous studies on SRC have compared the outcomes of concussions in male and female athletes after injury, research pertaining to why female athletes have worse outcomes is limited.

Purpose:

To determine the factors that predispose female athletes to more severe concussions than their male counterparts.

Study Design:

Systematic review; Level or evidence, 3.

Methods:

A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines. The MEDLINE, EMBASE, CINAHL, PsychINFO, and Cochrane Library databases were systematically searched on July 5 to July 20, 2018. Included were cohort, case-control, and cross-sectional studies that examined the effects of concussive and subconcussive head impacts in only female athletes of all ages, regardless of competition level. These studies were further supplemented with epidemiologic studies. Exclusion criteria included narrative reviews, single case reports, abstracts and letters to the editor, and studies related to chronic traumatic brain injury.

Results:

A total of 25 studies met the inclusion criteria. Female athletes appear to sustain more severe concussions than male athletes, due in part to a lower biomechanical threshold tolerance for head impacts. Additionally, concussions may alter the hypothalamic-pituitary-ovarian axis, resulting in worse symptoms and amenorrhea. Although females are more likely to report concussions than males, underreporting still exists and may result in concussions going untreated.

Conclusion:

This systematic review demonstrates that female athletes may be more susceptible to concussion, have prolonged symptoms after a concussion, and are more likely to report a concussion than their male counterparts. However, underreporting still exists among female athletes. Possible factors that put female athletes at a higher risk for concussions include biomechanical differences and hormonal differences. To effectively prevent, diagnose, and treat concussions in female athletes, more research is required to determine when and how such injuries are sustained. Despite sex-based differences in the clinical incidence, reporting behavior, and outcomes of SRCs, female athletes remain an understudied population, resulting in lack of sex-specific treatment guidelines for female athletes postinjury.

Whole-Body Metabolism, Carbohydrate Utilization, and Caloric Energy Balance After Sport Concussion: A Pilot Study

BACKGROUND

Sport concussion (SC) causes an energy crisis in the brain by increasing energy demand, decreasing energy supply, and altering metabolic resources. Whole-body resting metabolic rate (RMR) is elevated after more severe brain injuries, but RMR changes are unknown after SC. The purpose of this study was to longitudinally examine energy-related changes in collegiate athletes after SC.

HYPOTHESIS

RMR and energy consumption will increase acutely after SC and will return to control levels with recovery.

STUDY DESIGN

Case-control study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A total of 20 collegiate athletes with SC (mean age, 19.3 ± 1.08 years; mean height, 1.77 ± 0.11 m; mean weight, 79.6 ± 23.37 kg; 55% female) were compared with 20 matched controls (mean age, 20.8 ± 2.17 years; mean height, 1.77 ± 0.10 m; mean weight, 81.9 ± 23.45 kg; 55% female). RMR, percentage carbohydrate use (%CHO), and energy balance (EBal; ratio between caloric consumption and expenditure) were assessed 3 times: T₁, ≤72 hours after SC; T₂, 7 days after T₁; and T_F, after symptom resolution. A 2 × 2 × 3 (group × sex × time) multivariate analysis of variance assessed RMR, %CHO, and EBal. Changes in RMR, %CHO, and EBal (T₁ to T_F) were correlated with days to symptom-free and days to return to play in the concussed group.

RESULTS

Women reported being symptom-free (median, 6 days; range, 3-10 days) sooner than men (median, 11 days; range, 7-16 days). RMR and %CHO did not differ across time between groups or for group × sex interaction. SC participants had higher EBal than controls at T₁ (P = 0.016) and T₂ (P = 0.010). In men with SC, increasing %CHO over time correlated with days to symptom-free (r = 0.735 and P = 0.038, respectively) and days to return to play (r = 0.829 and P = 0.021, respectively).

CONCLUSION

Participants with SC were in energy surplus acutely after injury. Although women recovered more quickly than men, men had carbohydrate metabolism changes that correlated with recovery time.

CLINICAL RELEVANCE

This pilot study shows that male and female student-athletes may have differing physiologic responses to SC and that there may be a role for dietary intervention to improve clinical outcomes after SC.

Incidence reporting via online high school concussion surveillance by certified athletic trainers and school nurses, 2015-2018

BACKGROUND

There is an increasing concern over adolescent concussions in sports due to risks of long-term negative effects. This study analyzed data over three school years on reported concussion incidence rates by season, high school grade levels and gender, and reported symptoms by school nurses versus athletic trainers, from New Jersey student-athlete concussion data available from an online school-based surveillance system.

METHODS

School nurses and athletic trainers reported 300 concussions within five days from when each occurred over three school years, 2015-2018, in team sports and physical education in New Jersey high schools. Analysis was further conducted on symptoms and number of symptoms reported by school nurses versus school athletic trainers for each documented student-athlete concussion. Estimated concussion incidence rates were calculated using state agency verified school enrollment data.

FINDINGS

Concussions most commonly occurred during fall, followed by spring, then winter. Concussion incidence rates ranged from 6.3/1000 (4.99, 7.55) - 9.1/1000 (7.27, 10.98) students over the three school years of the study. Athletic trainers completed 86% of the reports while nurses completed 11% (position or title of 3%, or n = 7, were not disclosed); the values were similar when considering only fall pre-season and regular season sports (88, 10, 2%, respectively). On average, across the three school years, athletic trainers reported about 3.5 symptoms per report while nurses reported 2.7 (values in fall seasons only were 3.7 and 3.1, respectively.) CONCLUSIONS: Certified athletic trainers, compared to school nurses, more often completed concussion report forms and reported more symptoms per injured student, perhaps due partly to closer contact and immediate care provided after injury. Additionally, this study had a higher concussion incidence rate during fall sports seasons compared to winter and spring. Future research can further improve our understanding of concussions among adolescent student-athletes to better inform concussion identification, management and recovery protocols.

Repetitive head injury in adolescent mice: A role for vascular inflammation

Repetitive mild traumatic brain injury during adolescence can induce neurological dysfunction through undefined mechanisms. Interleukin-1 (IL-1) contributes to experimental adult diffuse and contusion TBI models, and IL-1 antagonists have entered clinical trials for severe TBI in adults; however, no such data exist for adolescent TBI. We developed an adolescent mouse repetitive closed head injury (rCHI) model to test the role of IL-1 family members in post-injury neurological outcome. Compared to one CHI, three daily injuries (3HD) produced acute and chronic learning deficits and emergence of hyperactivity, without detectable gliosis, neurodegeneration, brain atrophy, and white matter loss at one year. Mature IL-1β and IL-18 were induced in brain endothelium in 3HD but not 1HD, three hit weekly, or sham animals. IL-1β processing was induced cell-autonomously in three-dimensional human endothelial cell cultures subjected to in vitro concussive trauma. Mice deficient in IL-1 receptor-1 or caspase-1 had improved post-injury Morris water maze performance. Repetitive mild CHI in adolescent mice may induce behavioral deficits in the absence of significant histopathology. The endothelium is a potential source of IL-1β and IL-18 in rCHI, and IL-1 family members may be therapeutic targets to reduce or prevent neurological dysfunction after repetitive mild TBI in adolescents.

Chronic Neurobehavioral Sex Differences in a Murine Model of Repetitive Concussive Brain Injury

Traumatic brain injury (TBI) resulting from repeated head trauma is frequently characterized by diffuse axonal injury and long-term motor, cognitive and neuropsychiatric symptoms. Given the delay, often decades, between repeated head traumas and the presentation of symptoms in TBI patients, animal models of repeated injuries should be studied longitudinally to properly assess the longer-term effects of multiple concussive injuries on functional outcomes. In this study, male and cycling female C57BL/6J mice underwent repeated (three) concussive brain injuries (rCBI) delivered via a Leica ImpactOne cortical impact device and were assessed chronically on motor (open field and rotarod), cognitive (y-maze and active place avoidance), and neuropsychiatric (marble-burying, elevated zero maze and tail suspension) tests. Motor deficits were significant on the rotarod on the day following the injuries, and slight impairment remained for up to 6 months. All mice that sustained rCBI had significant cognitive deficits on the active place avoidance test and showed greater agitation (less immobility) in the tail suspension test. Only injured male mice were significantly hyperactive in the open field, and had increased time spent in the open quadrants of the elevated zero maze. One year after the injuries, mice of both sexes exhibited persistent pathological changes by the presence of Prussian blue staining (indication of prior microbleeds), primarily in the cortex at the site of the injury, and increased GFAP staining in the perilesional cortex and axonal tracts (corpus callosum and optic tracts). These data demonstrate that a pathological phenotype with motor, cognitive, and neuropsychiatric symptoms can be observed in an animal model of rCBI for at least one year post-injury, providing a pre-clinical setting for the study of the link between multiple brain injuries and neurodegenerative disorders. Furthermore, this is the first study to include both sexes in a pre-clinical long-term rCBI model, and female mice are less impaired functionally than males.

Female athletes: managing risk and maximizing benefit

PURPOSE OF REVIEW

The purpose of this review is to provide an updated summary on the unique aspects of caring for female youth and adolescent athletes.

RECENT FINDINGS

Recent research on female athletes has led to a better understanding of injuries and conditions that are more likely to occur in female youth and adolescent athletes, including the frequency and severity of concussions, musculoskeletal injury such as involving the anterior cruciate ligament, and the female athlete triad. Social factors, such as the growing pressure to specialize in a sport particularly at an early age, also put young female athletes at risk for issues such as overuse injuries. Researchers continue to explore the benefits of athletic participation that extend beyond physical fitness.

SUMMARY

Female participation in youth sports has increased dramatically during the past 50 years. This has led to greater research on how to manage risks and maximize benefits for young female athletes, although there is still much to be learned. Providers should educate patients, parents, and coaches on both the increased risks for female athletes and ways to provide better support and accessibility of youth sports to all children.

Trends in concussions at Ontario schools prior to and subsequent to the introduction of a concussion policy - an analysis of the Canadian hospitals injury reporting and prevention program from 2009 to 2016

BACKGROUND

Concussion is a preventable injury that can have long-term health consequences for children and youth. In Ontario, the Policy/Program Memorandum # 158 (PPM) was introduced by the Ministry of Education of Ontario in March 2014. The PPM's main purpose is to require each school board in the province to create and implement a concussion policy. The purpose of this paper is to examine trends in school-based concussions prior to and subsequent to the introduction of the PPM.

METHODS

This report examined emergency department (ED) visits in 5 Ontario hospitals that are part of the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), and compared trends over time in diagnosed concussions, and suspected concussions identified as "other head injury" in children and youth aged 4-18.

RESULTS

From 2009 to 2016 study years, there were 21,094 suspected concussions, including 8934 diagnosed concussions in youth aged 4-18. The average number of diagnosed concussions in the 5 years before the PPM was 89 concussions/month, compared to approximately 117 concussions per month after; a 30% increase in the monthly rate of concussions presenting to the ED. The total number of concussion or head injury-related ED visits remained relatively unchanged but the proportion of diagnosed concussions rose from 31% in 2009 to 53% in 2016. The proportion of diagnosed concussions in females also increased from 38% in 2013 to 46% in 2016. The percent of all diagnosed concussions occurring at schools increased throughout the study reaching almost 50% in 2016 with most injuries taking place at the playground (24%), gymnasium (22%) or sports field (20%).

CONCLUSIONS

The introduction of the PPM may have contributed to a general increase in concussion awareness and an improvement in concussion identification at the school level in children and youth aged 4-18.

Sex differences in white matter alterations following repetitive subconcussive head impacts in collegiate ice hockey players

Objective

Repetitive subconcussive head impacts (RSHI) may lead to structural, functional, and metabolic alterations of the brain. While differences between males and females have already been suggested following a concussion, whether there are sex differences following exposure to RSHI remains unknown. The aim of this study was to identify and to characterize sex differences following exposure to RSHI.

Methods

Twenty-five collegiate ice hockey players (14 males and 11 females, 20.6 ± 2.0 years), all part of the Hockey Concussion Education Project (HCEP), underwent diffusion-weighted magnetic resonance imaging (dMRI) before and after the Canadian Interuniversity Sports (CIS) ice hockey season 2011-2012 and did not experience a concussion during the season. Whole-brain tract-based spatial statistics (TBSS) were used to compare pre- and postseason imaging in both sexes for fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Pre- and postseason neurocognitive performance were assessed by the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT).

Results

Significant differences between the sexes were primarily located within the superior longitudinal fasciculus (SLF), the internal capsule (IC), and the corona radiata (CR) of the right hemisphere (RH). In significant voxel clusters (p < 0.05), decreases in FA (absolute difference pre- vs. postseason: 0.0268) and increases in MD (0.0002), AD (0.00008), and RD (0.00005) were observed in females whereas males showed no significant changes. There was no significant correlation between the change in diffusion scalar measures over the course of the season and neurocognitive performance as evidenced from postseason ImPACT scores.

Conclusions

The results of this study suggest sex differences in structural alterations following exposure to RSHI. Future studies need to investigate further the underlying mechanisms and association with exposure and clinical outcomes.