The effects of menstrual cycle phase on clinical measures of concussion in healthy college-aged females

Hormonal Contraceptive Influence on Baseline Vestibular/Ocular Symptomatology and Provocation for Concussion

Background

Hormonal contraceptives (HCs) and the menstrual cycle have been suggested to affect symptom severity and postconcussion recovery. Additionally, hormones have been a suggested rationale for sex differences between female and male athletes on concussion assessment. Researchers have yet to explore the effects of HC use on baseline symptomatology, including symptom reporting and provocation.

Purpose

To examine the influence of HC use on a baseline symptom reporting and vestibular/ocular provocation battery.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 61 college-aged individuals (21 HC-using women, 21 non-HC-using women, 19 men) were administered a baseline symptom battery consisting of the Post-Concussion Symptom Scale (PCSS), Headache Impact Test-6 (HIT-6), Pediatric Vestibular Symptom Questionnaire (PVSQ), and Vestibular/Ocular Motor Screening (VOMS). The main outcome measures consisted of PCSS symptom reporting (total symptoms, symptom severity score, and symptom factors), HIT-6 and PVSQ total scores, and VOMS item (ie, saccades, convergence, or vestibular/ocular reflex) symptom provocation scores.

Results

Significant differences were reported on HIT-6, with the highest headache reporting in the HC group (P = .026). On the PVSQ, the HC group also reported greater dizziness and unsteadiness symptoms than the non-HC group (P = .023). Similar findings existed on the PCSS, with the HC group reporting greater total symptoms (P < .001), symptom severity (P < .001), and vestibular-somatic (P = .024), cognitive-sensory (P = .004), sleep-arousal (P = .001), and affective (P < .001) factors compared with the non-HC group. Smooth pursuit (ie, following finger smoothly with eyes) was the only VOMS items with differences between groups (P = .003), with the HC group having greater provocation compared with non-HC users (P = .020).

Conclusion

HC use was associated with overall symptomatology and worse self-reported symptoms on vestibular-related inventories and concussion symptom scales and factors when compared with non-HC users and male controls. Additionally, HC users reported higher VOMS provocation scores on the smooth pursuit item than non-HC users and male controls.

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.

A pilot study examining BDNF Val66Met polymorphism and biological sex: Relationships with baseline cognitive functioning in adolescent athletes

The purpose of this exploratory study was to examine interactive relationships between a common brain-derived neurotrophic factor (BDNF) polymorphism (Val66Met) and biological sex on cognitive functioning in a sample of healthy adolescent athletes. Participants included 82 student athletes (age: M = 12.85 years, SD = 1.13) who were involved in a clinically-based sports-concussion management program. Athletes completed the ImPACT computerized battery at baseline and provided buccal samples for determination of their BDNF genotype. Two-way ANOVAs were used to evaluate the effect of BDNF genotype (Met+ vs. Met-) and sex (male vs. female) on cognitive functioning (subgroup n's: Female/Met+ = 12, Female/Met- = 26, Male/Met+ = 12, Male/Met- = 32). ANOVAs revealed non-significant main effects for both BDNF genotype and sex across all four cognitive composites. However, there was a significant BDNF genotype by sex interaction for the visual-motor speed composite (p = .015; ηp2 = .073), such that female Met carriers demonstrated better performance than male Met carriers. In contrast, no differences were found on visual-motor speed performance between females and males without a Met allele. Although these results will need to be replicated using larger samples, our preliminary findings lend support to the view that the Met allele may be somewhat neuroprotective in healthy adolescent females.

Neurological Health in Sexual and Gender Minority Individuals

Despite representing a significant proportion of the U.S. population, there is a paucity of population-based research on the health status and health needs of sexual and gender minority (SGM) individuals in neurology. Compared with heterosexual peers, some SGM populations have a higher burden of chronic health conditions. In parallel, SGM individuals are more likely to experience stigma and discrimination producing psychological distress, which may contribute to and be compounded by reduced health care access and utilization. In this narrative review, we summarize the existing literature on common neurological health conditions such as stroke, headache, epilepsy, movement disorders, and traumatic brain injury through the lens of intersection of SGM identity. Special focus is attuned to social determinants of health and gender-affirming hormonal therapy. Given the limitations in the available literature, there is an urgent unmet need for datasets that include sexual orientation and gender identity information, as well as funding for research that will characterize the prevalence of neurological conditions, unique risk factors, and health outcomes in SGM populations. In the health care community, providers should address deficiencies in their professional training and integrate inclusive language into their clinical skillset to build trust with SGM patients. There is an opportunity in neurology to proactively engage SGM communities, collaborate to remove barriers to care, promote resilience, and develop targeted interventions to ensure high-quality, culturally competent care for SGM populations to improve neurological health for all.

Exploring the relationship between contraceptive medication use and concussion recovery in female collegiate athletes: a LIMBIC MATARS consortium investigation

OBJECTIVE

While recovery from concussion is variable, women are more likely to report symptoms, experience worse outcomes, and have longer recovery trajectories following concussion than men. Preliminary data suggest that hormonal fluctuations, specifically progesterone, may be associated with this variability. This study aimed to understand the effect of contraceptive medication on concussion recovery.

METHODS

A retrospective chart review using consensus-based common data elements was conducted at 11 NCAA institutions as part of the LIMBIC MATARS consortium. Participants included female collegiate athletes diagnosed with a concussion who did (n = 117) or did not report (n = 339) contraceptive medication use. Number of days between diagnosis and symptom resolution were compared using Mann-Whitney U tests. Self-reported diagnosis of attention deficit hyperactivity disorder, concussion history, anxiety, and depression was compared using Chi-squared tests.

RESULTS

The proportions of participants who did or did not take contraceptive medication were similar across covariates. Female athletes regardless of contraceptive medication use recovered similarly following a concussion.

CONCLUSIONS

Our findings suggest that contraceptive medication use did not significantly impact concussion recovery. Future prospective investigations should examine documentation practices and operationalize terminology for hormonal contraceptive medication to better understand their role on recovery from sport-related concussion in female collegiate athletes.

p17/C18-ceramide-mediated mitophagy is an endogenous neuroprotective response in preclinical and clinical brain injury

Repeat concussions (or repetitive mild traumatic brain injury [rmTBI]) are complex pathological processes consisting of a primary insult and long-term secondary complications and are also a prerequisite for chronic traumatic encephalopathy (CTE). Recent evidence implies a significant role of autophagy-mediated dysfunctional mitochondrial clearance, mitophagy, in the cascade of secondary deleterious events resulting from TBI. C18-ceramide, a bioactive sphingolipid produced in response to cell stress and damage, and its synthesizing enzyme (CerS1) are precursors to selective stress-mediated mitophagy. A transporter, p17, mediates the trafficking of CerS1, induces C18-ceramide synthesis in the mitochondrial membrane, and acts as an elimination signal in cell survival. Whether p17-mediated mitophagy occurs in the brain and plays a causal role in mitochondrial quality control in secondary disease development after rmTBI are unknown. Using a novel repetitive less-than-mild TBI (rlmTBI) injury paradigm, ablation of mitochondrial p17/C18-ceramide trafficking in p17 knockout (KO) mice results in a loss of C18-ceramide-induced mitophagy, which contributes to susceptibility and recovery from long-term secondary complications associated with rlmTBI. Using a ceramide analog with lipid-selenium conjugate drug, LCL768 restored mitophagy and reduced long-term secondary complications, improving cognitive deficits in rlmTBI-induced p17KO mice. We obtained a significant reduction of p17 expression and a considerable decrease of CerS1 and C18-ceramide levels in cortical mitochondria of CTE human brains compared with age-matched control brains. These data demonstrated that p17/C18-ceramide trafficking is an endogenous neuroprotective mitochondrial stress response following rlmTBI, thus suggesting a novel prospective strategy to interrupt the CTE consequences of concussive TBI.

Menstrual Cycle Patterns After Concussion in Adolescent Patients

OBJECTIVE

To describe menstrual cycle patterns in adolescents with concussion and investigate whether menstrual cycle phase at injury influenced postconcussion cycle pattern changes or concussion symptoms.

STUDY DESIGN

Data were collected prospectively from patients aged 13-18 years presenting to a specialty care concussion clinic for an initial visit (≤28 days postconcussion) and, if clinically indicated, at a follow-up visit 3-4 months postinjury. Primary outcomes included menstrual cycle pattern change since injury (change/no change), menstrual cycle phase at time of injury (calculated using date of last period before injury), and symptom endorsement and severity, measured by Post-Concussion Symptom Inventory (PCSI). Fisher exact tests were used to determine the association between menstrual phase at injury and change in cycle pattern. Multiple linear regression was used to determine whether menstrual phase at injury was associated with PCSI endorsement and symptom severity, adjusting for age.

RESULTS

Five hundred twelve postmenarchal adolescents were enrolled (age 15.2 ± 1.4 years), with 111 (21.7%) returning for follow-up at 3-4 months. Menstrual pattern change was reported by 4% of patients at initial visit and 10.8% of patients at follow-up. At 3-4 months, menstrual phase at injury was not associated with menstrual cycle changes (P = .40) but was associated with endorsement of concussion symptoms on the PCSI (P = .01).

CONCLUSIONS

At 3-4 months' postconcussion, 1 in 10 adolescents experienced a change in menses. Menstrual cycle phase at injury was associated with postconcussion symptom endorsement. Leveraging a large sample of postconcussion menstrual patterns, this study represents foundational data regarding potential menstrual cycle effects of concussion in female adolescents.

Baseline Computerized Neurocognitive Testing and Oculomotor Measures are not Altered by Hormonal Contraceptive Use

OBJECTIVE

Neurocognitive testing and oculomotor assessment have been an integral component to provide objective measures for sport-related concussion (SRC) detection and management. Hormonal contraceptive (HC) use is common among collegiate female athletes and may modify baseline SRC performance. The purpose was to examine the effects of HC use on baseline computerized neurocognitive testing (CNT) and oculomotor testing in college-aged individuals.

METHOD

A total of 63 participants (22 HC using females, 22 non-HC using females, 19 males) completed a baseline SRC battery consisting of CNT, near point of convergence (NPC), and the King-Devick (KD) test. CNT measures were composite scores of verbal and visual memory, visual motor processing speed and reaction time, impulse control, and cognitive efficiency index (CEI). NPC was measured as the average convergence distance across three trials. KD time was recorded as total time for each of the two trials and best trial marked as baseline.

RESULTS

There were no group differences between HC, non-HC, and male control groups on all baseline CNT composite scores (p = .13-.98), impulse control (p = .47), and CEI (p = .49). NPC distance was similar between groups (p = .41), as well as KD time by trial (Trial 1 p = .65; 2 p = .48) and best time (p = .49).

CONCLUSIONS

HC use does not appear to influence baseline SRC measures of neurocognition and oculomotor assessment. Clinicians should continue to consider the effects of modifying factors at baseline and post-concussion. Additional research is needed to better understand sex hormone levels and SRC performance measures.

Mental rotation, episodic memory, and executive control: Possible effects of biological sex and oral contraceptive use

Oral contraceptives (OCs) are one of the most common forms of hormonal birth control. A small literature suggests that OC use may affect visuospatial ability, episodic memory, and executive control. However, previous studies have been criticized for small sample sizes and the use of different, single cognitive tests. We investigated the degree to which biological sex and OC use might affect individual mental rotation, episodic memory, and executive control in a large sample of healthy, young adults (N = 155, including 52 OC users, 53 naturally cycling females, and 50 males) tested individually over videoconference. To measure cognition, we used a set of neuropsychological tasks inspired by Glisky and colleagues' two-factor episodic memory and executive control battery, from which two composite scores (based on principal component analysis) were derived for each participant. Our pre-registered analysis revealed a clear female advantage in episodic memory, independent of OC use. In an exploratory analysis, gist memory was elevated in OC users. Interestingly, we found no significant sex-related differences nor effects of OC use on mental rotation or executive control. Duration of OC use was also not related to any of our cognitive measures. These results suggest that the use of combined, monophasic OCs does not lead to many significant changes in cognition in young adults, although young females overall may have better episodic memory than young males. Additional studies, including longitudinal designs and looking in more detail at the menstrual cycle and OC use history, will further clarify the effects of different types of OCs and their duration of use on different aspects of cognition.

Oral contraceptives and cognition: A systematic review

Oral contraceptives (OCs) are widely used. While the physical impacts of OCs have been well researched, there is increasing interest on potential impacts of OCs on brain, behaviour and cognition. We systematically reviewed the literature to determine the influence of OCs on cognition, including neurocognition, social cognition and emotional processing. Inclusionary criteria were: (a) premenopausal females taking OCs; (b) a control group of naturally cycling women or OCs users in their inactive (i.e. 'sugar pill') phase; and (c) at least one measure of performance on a neurocognitive or social cognitive task. The systematic review found that OC use was associated with some differences in performance on all cognitive domains examined (with the exception of basic auditory attention and psychomotor performance). Several factors were identified that are likely to modulate the way OCs influence cognition, including task related factors, OC type and control group characteristics. Directions for future research are highlighted.

Characterizing Sex Differences in Clinical and Functional Outcomes Among Military Veterans with a Comprehensive Traumatic Brain Injury Evaluation (CTBIE): A Million Veteran Program (MVP) Study

Using a diverse sample of military Veterans enrolled in the VA's Million Veteran Program (N=14,378; n=1,361 females [9.5%]; all previously deployed), we examined sex differences on the Comprehensive Traumatic Brain Injury Evaluation (CTBIE), a structured traumatic brain injury (TBI) interview routinely administered within the VA. Confirmed TBI diagnoses were more frequent among males than females (65% vs. 58%). Additionally, when compared to females, a greater proportion of males with CTBIE-confirmed TBI histories experienced blast-related injuries and were employed. In contrast, a greater proportion of females reported experiencing falls, sustaining a TBI since deployment, and having more severe neurobehavioral symptoms (particularly affective-related symptoms). Results indicate that males and females experience differential clinical and functional outcomes in the aftermath of military TBI. Findings underscore the need to increase female representation in TBI research to increase understanding of sex-specific experiences with TBI and to improve the clinical care targeted to this vulnerable population.

What is there to know about the effects of progestins on the human brain and cognition?

Progestins are an important component of hormonal contraceptives (HCs) and hormone replacement therapies (HRTs). Despite an increasing number of studies elucidating the effects of HCs and HRTs, little is known about the effects of different types of progestins included in these medications on the brain. Animal studies suggest that various progestins interact differently with sex steroid, mineralocorticoid and glucocorticoid receptors and have specific modulatory effects on neurotransmitter systems and on the expression of neuropeptides, suggesting differential impacts on cognition and behavior. This review focuses on the currently available knowledge from human behavioral and neuroimaging studies pooled with evidence from animal research regarding the effects of progestins on the brain. The reviewed information is highly relevant for improving women's mental health and making informed choices regarding specific types of contraception or treatment.

Sex and gender differences in mild traumatic brain injury/concussion

The high incidence of concussions/mild traumatic brain injury and the significant number of people with persisting concussion symptoms as well as the concern for delayed, neurodegenerative effects of concussions makes them a major public health concern. There is much to learn on concussions with respect to pathophysiology as well as vulnerability and resiliency factors. The heterogeneity in outcome after a concussion warrants a more personalized approach to better understand the biological and psychosocial factors that may affect outcome. In this chapter we address biological sex and gender as they impact different aspects of concussion including incidence, risk factors and outcome. As well, this chapter will provide a more fulsome overview of intimate partner violence, an often-overlooked cause of concussion in women. Applying the sex and gender lens to concussion/mild traumatic brain injury is imperative for discovery of its pathophysiology and moving closer to treatments.

Chronic treatment with hormonal contraceptives alters hippocampal BDNF and histone H3 post-translational modifications but not learning and memory in female rats

Hormonal contraceptives prevent ovulation with subsequent reduction in endogenous levels of estradiol, progesterone and its neuroactive metabolite allopregnanolone. These neurosteroids modulate several brain functions, including neuronal plasticity, cognition and memory. We hypothesized that hormonal contraceptives might affect synaptic plasticity, learning and memory, as a consequence of suppressed endogenous hormones levels. Female rats were orally treated with a combination of ethinyl estradiol (EE, 0.020 mg) and levonorgestrel (LNG, 0.060 mg) once daily for four weeks. Decreased hippocampal brain-derived neurotrophic factor (BDNF) levels and altered histone H3 post-translational modifications (PTMs) were observed 14 days after discontinuation from chronic EE-LNG treatment. These effects were not accompanied by alterations in long-term plasticity at glutamatergic synapses, recognition memory in the novel object and novel place location tests, or spatial learning, memory, and behavioral flexibility in the Morris water maze test. Thus, decreased BDNF content does not affect synaptic plasticity and cognitive performance; rather it might be relevant for the occurrence of certain psychiatric symptoms, reported by some women using hormonal contraceptives. These results provide the first evidence of hippocampal epigenetic changes induced by hormonal contraceptives and complement previous studies on the neurobiological actions of hormonal contraceptives; the finding that effects of chronic EE-LNG treatment on BDNF content and histone PTMs are observed 14 days after drug discontinuation warrants further investigation to better understand the implications of such long-term consequences for women's health.

The Incidence, Cost, and Burden of Concussion in Women's Rugby League and Rugby Union: A Systematic Review and Pooled Analysis

BACKGROUND

The extent of concussion injury in the rugby codes for women is unclear.

OBJECTIVE

Our aim was to review all published studies reporting concussion injuries from match and training participation in rugby codes and report the pooled data estimates for rugby league and union concussion injury epidemiology.

METHODS

We conducted a systematic literature analysis of concussion in rugby league and rugby union for published studies from January 1990 to July 2021. Data from 16 studies meeting the inclusion criteria were extracted for women's concussion injuries and were subsequently pooled. Costs from Accident Compensation Corporation (ACC) data were attributed to the results to provide cost estimates.

RESULTS

The pooled analysis match injury incidence of women's concussion was higher for rugby league (10.3 per 1000 match hours) than rugby 15 s (2.8 per 1000 match hours) or rugby 7 s (8.9 per 1000 match hours). There was a fourfold difference in the pooled incidence of concussion in women's rugby league (risk ratio [RR] 4.53, 95% confidence interval [CI] 1.8-11.3]; p = 0.0001) when compared with rugby 15 s. There was also a ninefold higher risk of a concussion during match participation compared with training participation for women's rugby 15 s (RR 9.3, 95% CI 1.29-66.78; p = 0.0070). The total estimated costs for the concussions reported were NZ$1,235,101. For rugby 7 s, the pooled concussive injury burden was 33.2 days.

CONCLUSIONS

Our pooled analysis clarified the extent of concussion injury and the possible associated costs at several levels of the game for women's rugby codes. The pooled mean days lost because of concussions was 33 days. As this was considerably longer than the 7- to 10-day expected timeframe outlined in the Concussion in Sport Consensus statement, these guidelines need to be updated to include sex-specific differences.

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.

How hormonal contraceptives shape brain and behavior: A review of preclinical studies

Steroid hormones influence different aspects of brain function, including development, neurogenesis, neuronal excitability, and plasticity, thus affecting emotional states, cognition, sociality, and reward. In women, their levels fluctuate across the lifespan and through the reproductive stages but are also altered by exogenous administration of hormonal contraceptives (HC). HC are widely used by women throughout their fertile life both for contraceptive and therapeutic benefits. However, awareness of their effects on brain function and behavior is still poorly appreciated, despite the emerging evidence of their action at the level of the central nervous system. Here, we summarize results obtained in preclinical studies, mostly conducted in intact female rodents, aimed at investigating the neurobiological effects of HC. HC can alter neuroactive hormones, neurotransmitters, neuropeptides, as well as emotional states, cognition, social and sexual behaviors. Animal studies provide insights into the neurobiological effects of HC with the aim to improve women's health and well-being.

Repeated Mild TBI in Adolescent Rats Reveals Sex Differences in Acute and Chronic Behavioral Deficits

High school students who participate in contact sports are vulnerable to sustaining multiple concussions and exhibit deficits in cognitive function in both the acute and chronic phases and in emotional behavior in the chronic phase. Further, boys are more likely to suffer cognitive problems whereas girls tend to report depression and anxiety. The effects of repetitive mild TBI in adolescent (35-40-day old) male and female Sprague-Dawley rats on object location and spatial working memory (hippocampal-dependent) and object recognition memory (hippocampal-independent) at 1-and-4-weeks post-injury along with trait-dependent anxiety- and depressive-like behaviors at 5 weeks were examined. Compared to sham-injured rats, male brain-injured rats demonstrated significant impairment in both hippocampal-dependent and -independent memory tasks at both time points, whereas female brain-injured rats only exhibited impairment in these tests at the 4-week time point. In contrast, depressive-like behaviors were present in the forced swim test in only the female brain-injured animals at 5 weeks post-injury; anxiety-like behaviors were not evident in either male or female brain-injured animals. Histological analysis at 6 weeks after injury revealed that repeated mild TBI in male and female adolescent rats resulted in increased reactivity of astrocytes and microglia within the corpus callosum below the impact site and in the stratum oriens and stratum pyramidale of the CA2 region of the dorsal hippocampus. Together, these data are indicative of the differences in the temporal pattern of post-traumatic behavioral deficits between male and female animals and that female animals may be more likely to develop deficits in the chronic post-traumatic period.

Comparing Imaging Biomarkers of Cerebral Edema after TBI in Young Adult Male and Female Rats

Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Cerebral edema following TBI is known to play a critical role in injury severity and prognosis. In the current study we used multimodal magnetic resonance imaging (MRI) to assess cerebral edema 24 hours after unilateral contusive TBI in male and female rats. We then directly quantified brain water content in the same subjectsex vivo.We found that both males and females had similarly elevated T₂ values after TBI compared with sham controls. Apparent diffusion coefficient (ADC) was more variable than T₂ and did not show significant injury effects in males or females. Brain water was elevated in male TBI rats compared with sham controls, but there was no difference between female TBI and sham groups. Notably, MRI biomarkers of edema were more closely correlated with brain water in male rats; female rats did not show any relationship between brain water and T₂ or ADC. These observations raise questions about the interpretation of radiological findings traditionally interpreted as edema in female TBI patients. A better understanding of sex differences and similarities in the pathophysiology of post-traumatic edema is needed to help improve patient management and the development of effective treatment strategies for men and women.

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.

Estradiol effects on spatial memory in women

To examine the role of estradiol in hippocampal-dependent spatial memory in women, 86 female undergraduates were tested in a virtual Morris water task (VMWT), a virtual radial arm maze (VRAM), and a mental rotation task (MRT) within a single daily session. The VMWT and RAM were also administered 24 h later to examine the effects of estradiol on memory consolidation. Women on oral contraceptives (OCs) or those who were naturally cycling and exhibited low estradiol (LE) or high estradiol (HE), as determined by salivary assays, were included. At the start of day two, the HE group showed superior spatial reference memory on the VMWT relative to the LE group, as evidenced by significantly shorter distances navigating to the hidden platform. The LE group also had the poorest probe trial performance at the start of day two compared to both other groups. There were no group differences in performance on the RAM or MRT. These results provide support for estradiol's role in the consolidation of spatial reference memory in women, and emphasize the differential sensitivities of various virtual memory tasks in assessing spatial memory function in women.

The Specificities of Elite Female Athletes: A Multidisciplinary Approach

Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18-40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Preliminary Report: Localized Cerebral Blood Flow Mediates the Relationship between Progesterone and Perceived Stress Symptoms among Female Collegiate Club Athletes after Mild Traumatic Brain Injury

Female athletes are under-studied in the field of concussion research, despite evidence of higher injury prevalence and longer recovery time. Hormonal fluctuations caused by the natural menstrual cycle (MC) or hormonal contraceptive (HC) use impact both post-injury symptoms and neuroimaging findings, but the relationships among hormone, symptoms, and brain-based measures have not been jointly considered in concussion studies. In this preliminary study, we compared cerebral blood flow (CBF) measured with arterial spin labeling between concussed female club athletes 3-10 days after mild traumatic brain injury (mTBI) and demographic, HC/MC matched controls (CON). We tested whether CBF statistically mediates the relationship between progesterone serum levels and post-injury symptoms, which may support a hypothesis for progesterone's role in neuroprotection. We found a significant three-way relationship among progesterone, CBF, and perceived stress score (PSS) in the left middle temporal gyrus for the mTBI group. Higher progesterone was associated with lower (more normative) PSS, as well as higher (more normative) CBF. CBF mediates 100% of the relationship between progesterone and PSS (Sobel p value = 0.017). These findings support a hypothesis for progesterone having a neuroprotective role after concussion and highlight the importance of controlling for the effects of sex hormones in future concussion studies.

A Role for the Amygdala in Impairments of Affective Behaviors Following Mild Traumatic Brain Injury

Mild traumatic brain injury (TBI) results in chronic affective disorders such as depression, anxiety, and fear that persist up to years following injury and significantly impair the quality of life for patients. Although a great deal of research has contributed to defining symptoms of mild TBI, there are no adequate drug therapies for brain-injured individuals. Preclinical studies have modeled these deficits in affective behaviors post-injury to understand the underlying mechanisms with a view to developing appropriate treatment strategies. These studies have also unveiled sex differences that contribute to the varying phenotypes associated with each behavior. Although clinical and preclinical studies have viewed these behavioral deficits as separate entities with unique neurobiological mechanisms, mechanistic similarities suggest that a novel approach is needed to advance research on drug therapy. This review will discuss the circuitry involved in the expression of deficits in affective behaviors following mild TBI in humans and animals and provide evidence that the manifestation of impairment in these behaviors stems from an amygdala-dependent emotional processing deficit. It will highlight mechanistic similarities between these different types of affective behaviors that can potentially advance mild TBI drug therapy by investigating treatments for the deficits in affective behaviors as one entity, requiring the same treatment.

Impact of menstrual cycle phase and oral contraceptives on sleep and overnight memory consolidation

Sleep spindles benefit declarative memory consolidation and are considered to be a biological marker for general cognitive abilities. However, the impact of sexual hormones and hormonal oral contraceptives (OCs) on these relationships are less clear. Thus, we here investigated the influence of endogenous progesterone levels of naturally cycling women and women using OCs on nocturnal sleep and overnight memory consolidation. Nineteen healthy women using OCs (M_Age = 21.4, SD = 2.1 years) were compared to 43 healthy women with a natural menstrual cycle (follicular phase: n = 16, M_Age = 21.4, SD = 3.1 years; luteal phase: n = 27, M_Age = 22.5, SD = 3.6 years). Sleep spindle density and salivary progesterone were measured during an adaptation and an experimental night. A word pair association task preceding the experimental night followed by two recalls (pre‐sleep and post‐sleep) was performed to test declarative memory performance. We found that memory performance improved overnight in all women. Interestingly, women using OCs (characterized by a low endogenous progesterone level but with very potent synthetic progestins) and naturally cycling women during the luteal phase (characterized by a high endogenous progesterone level) had a higher fast sleep spindle density compared to naturally cycling women during the follicular phase (characterized by a low endogenous progesterone level). Furthermore, we observed a positive correlation between endogenous progesterone level and fast spindle density in women during the luteal phase. Results suggest that the use of OCs and the menstrual cycle phase affects sleep spindles and therefore should be considered in further studies investigating sleep spindles and cognitive performance.

Training injury incidence in an amateur women's rugby union team in New Zealand over two consecutive seasons

OBJECTIVES

To describe the training injury incidence in amateur women's rugby union in New Zealand over two consecutive seasons.

DESIGN

A prospective cohort observational study METHODS: A total of 69 amateur women's rugby 15s team playerswere observed. Training exposure and training injury incidence were calculated.

RESULTS

The 38 training injuries resulted in a total injury incidence of 11.4 (8.3-15.6) per 1,000 training-hours. There were 12 injuries that resulted in a time-loss injury incidence of 3.6 (95% CI: 2.0-6.3) per 1,000 training-hours. Forwards recorded more total (RR: 1.8 [95% CI: 0.9-3.5]; p=0.0516) and time-loss (RR: 2.0 [95% CI: 0.6-6.6]; p=0.2482) injuries than Backs. The tackle was the most common injury cause for total (3.0 [95% CI: 1.6-5.6] per 1,000 training-hours.) injuries, but collisions (1.5 [95% CI: 0.6-3.6] per 1,000 training-hours.) with the ground or another person were the most common cause for time-loss injuries.The training injuries occurred most often to the lower limb and during the latter part of training sessions. These injuries were mostly minor in nature resulting in minimal time-loss away from training.

DISCUSSION

The time-loss injury incidence (3.6 per 1,000 training-hours.) for the amateur women's rugby 15s team players was higher than that reported for National (1.2 per 1,000 training-hours.) and Rugby World Cup for women (0.2 to 3.0 per 1,000 training-hours.) competitions.

CONCLUSION

The training injury incidence in amateur women's rugby union in New Zealand was higher than that reported for national and international rugby union injury incidences.

Sex as a Biological Variable in Preclinical Modeling of Blast-Related Traumatic Brain Injury

Approaches to furthering our understanding of the bioeffects, behavioral changes, and treatment options following exposure to blast are a worldwide priority. Of particular need is a more concerted effort to employ animal models to determine possible sex differences, which have been reported in the clinical literature. In this review, clinical and preclinical reports concerning blast injury effects are summarized in relation to sex as a biological variable (SABV). The review outlines approaches that explore the pertinent role of sex chromosomes and gonadal steroids for delineating sex as a biological independent variable. Next, underlying biological factors that need exploration for blast effects in light of SABV are outlined, including pituitary, autonomic, vascular, and inflammation factors that all have evidence as having important SABV relevance. A major second consideration for the study of SABV and preclinical blast effects is the notable lack of consistent model design—a wide range of devices have been employed with questionable relevance to real-life scenarios—as well as poor standardization for reporting of blast parameters. Hence, the review also provides current views regarding optimal design of shock tubes for approaching the problem of primary blast effects and sex differences and outlines a plan for the regularization of reporting. Standardization and clear description of blast parameters will provide greater comparability across models, as well as unify consensus for important sex difference bioeffects.

Beyond Binary: Influence of Sex and Gender on Outcome after Traumatic Brain Injury

Traumatic brain injury (TBI) affects millions of individuals each year and is a leading cause of death and disability worldwide. TBI is heterogeneous and outcome is influenced by a combination of factors that include injury location, severity, genetics, and environmental factors. More recently, sex as a biological variable has been incorporated into TBI research, although there is conflicting literature regarding clinical outcomes in males versus females after TBI. We review the current clinical literature investigating sex differences after TBI. We focus our discussion on differences within contemporary gender categories to suggest that binary categories of male and female are not sufficient to guide clinical decisions for neurotrauma. Some studies have considered physiological variables that influence sex such as hormone cycles and stages in males and females pre- and post-TBI. These data suggest that there are phasic differences within male populations and within female populations that influence an individual's outcome after TBI. Finally, we discuss the impact of gender identity and expression on outcome after TBI and highlight the lack of neurotrauma research that includes non-binary individuals. Social constructs regarding gender impact an individual's vulnerability to violence and consequent TBI, including the successful reintegration to society after TBI. We call for incorporation of gender beyond the binary in TBI education, research, and clinical care. Precision medicine necessarily must progress beyond the binary to treat individuals after TBI.

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.

Women Are at Higher Risk for Concussions Due to Ball or Equipment Contact in Soccer and Lacrosse

BACKGROUND

There is ample evidence to suggest sex- and gender-based differences in the incidence of sports-related concussions. The mechanisms of concussion may vary between male and female athletes and contribute to this observed difference. Understanding the underlying etiology by pooling data from primary studies across different settings and sport types will inform interventions that can reduce concussion rates.

QUESTIONS/PURPOSES

Specifically, we asked: (1) In which sports are female athletes less likely to experience concussions from player contact? (2) In which sports are female athletes more likely to experience concussions because of ball or equipment contact?

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched to identify articles published from January 2000 to December 2018. Ten studies met the inclusion criteria, which were studies that reported concussion incidence by mechanism for both male and female athletes. Exclusion criteria included non-English studies, conference abstracts, and studies on non-sports related concussions. The sports represented by the 10 studies included ice hockey (n = 4), soccer (n = 5), basketball (n = 4), baseball/softball (n = 4), and lacrosse (n = 5). The rate ratio was calculated as the incidence rate in female athletes/male athletes for each concussion mechanism or activity. Data were pooled using the DerSimonian-Laird random-effects model. Study quality was assessed with the Newcastle-Ottawa Scale.

RESULTS

Female athletes were at lower risk of player-contact-induced concussions in lacrosse (pooled rate ratio 0.33 [95% CI 0.25 to 0.43]; p < 0.001), basketball (pooled rate ratio 0.86 [95% CI 0.76 to 0.97]; p = 0.01), ice hockey (pooled rate ratio 0.64 [95% CI 0.56 to 0.73]; p < 0.001), soccer (pooled rate ratio 0.70 [95% CI 0.66 to 0.75]; p < 0.001), and soccer heading (pooled rate ratio 0.80 [95% CI 0.72 to 0.90]; p < 0.001); in these sports, men were at higher risk of concussions from player contact. Female athletes were more likely to experience concussions because of ball or equipment contact in lacrosse (pooled rate ratio 3.24 [95% CI 2.10 to 4.99]; p < 0.001), soccer (pooled rate ratio 2.04 [95% CI 1.67 to 2.49]; p < 0.001), and soccer heading (pooled rate ratio 2.63 [95% CI 1.84 to 3.77]; p < 0.001).

CONCLUSIONS

The mechanism or activity underlying concussions differs between male and female athletes across different sports. This finding remains the same regardless of whether there are rule differences between the men's and women's games. The implementation of other interventions are required to further ensure player safety, including protective head equipment, concussion prevention training, or rules limiting player contact in the men's game.

LEVEL OF EVIDENCE

Level III, retrospective study.

Match and Training Injuries in Women's Rugby Union: A Systematic Review of Published Studies

BACKGROUND

There is a paucity of studies reporting on women's injuries in rugby union.

OBJECTIVE

The aim of this systematic review was to describe the injury epidemiology for women's rugby-15s and rugby-7s match and training environments.

METHODS

Systematic searches of PubMed, SPORTDiscus, Web of Science Core Collection, Scopus, CINAHL(EBSCO) and ScienceDirect databases using keywords.

RESULTS

Ten articles addressing the incidence of injury in women's rugby union players were retrieved and included. The pooled incidence of injuries in women's rugby-15s was 19.6 (95% CI 17.7-21.7) per 1000 match-hours (h). Injuries in women's rugby-15s varied from 3.6 (95% CI 2.5-5.3) per 1000 playing-h (including training and games) to 37.5 (95% CI 26.5-48.5) per 1000 match-h. Women's rugby-7s had a pooled injury incidence of 62.5 (95% CI 54.7-70.4) per 1000 player-h and the injury incidence varied from 46.3 (95% CI 38.7-55.4) per 1000 match-h to 95.4 (95% CI 79.9-113.9) per 1000 match-h. The tackle was the most commonly reported injury cause with the ball carrier recording more injuries at the collegiate [5.5 (95% CI 4.5-6.8) vs. 3.5 (95% CI 2.7-4.6) per 1000 player-game-h; χ²₍₁₎ = 6.7; p = 0.0095], and Women's Rugby World Cup (WRWC) [2006: 14.5 (95% CI 8.9-23.7) vs. 10.9 (95% CI 6.2-19.2) per 1000 match-h; χ²₍₁₎ = 0.6; p = 0.4497; 2010: 11.8 (95% CI 6.9-20.4) vs. 1.8 (95% CI 0.5-7.3) per 1000 match-h; χ²₍₁₎ = 8.1; p = 0.0045] levels of participation. Concussions and sprains/strains were the most commonly reported injuries at the collegiate level of participation.

DISCUSSION

Women's rugby-7s had a higher un-pooled injury incidence than women's rugby-15s players based on rugby-specific surveys and hospitalisation data. The incidence of injury in women's rugby-15s and rugby-7s was lower than men's professional rugby-15s and rugby-7s competitions but similar to male youth rugby-15s players. Differences in reporting methodologies limited comparison of results.

CONCLUSION

Women's rugby-7s resulted in a higher injury incidence than women's rugby-15s. The head/face was the most commonly reported injury site. The tackle was the most common cause of injury in both rugby-7s and rugby-15s at all levels. Future studies are warranted on injuries in women's rugby-15s and rugby-7s.

PROSPERO REGISTRATION NUMBER

CRD42018109054 (last updated on 17 January 2019).

Effects of Oral Contraceptive Androgenicity on Visuospatial and Social-Emotional Cognition: A Prospective Observational Trial

Oral contraceptives (OCs) containing estrogen and progesterone analogues are widely used amongst reproductive-aged women, but their neurocognitive impact is poorly understood. Preliminary studies suggest that OCs improve verbal memory and that OCs with greater androgenic activity may improve visuospatial ability. We sought to explore the cognitive impact of OCs by assessing performance of OC users at different stages of the OC cycle, and comparing this performance between users of different OC formulations according to known androgenic activity. We conducted a prospective, observational trial of OC users, evaluating cognitive performance with CogState software on two occasions: days 7-10 of active hormonal pill phase, and days 3-5 of the inactive pill phase (coinciding with the withdrawal bleed resembling menstruation). Thirty-five OC users (18 taking androgenic formulations, 17 taking anti-androgenic) were assessed. Analysis by androgenic activity showed superior performance by users of androgenic OCs, as compared to anti-androgenic OCs, in visuospatial ability and facial affect discrimination tasks. A growing understanding of cognitive effects of OC progestin androgenicity may have implications in choice of OC formulation for individuals and in future OC development.

The brain as a target of hormonal contraceptives: Evidence from animal studies

Hormonal contraceptives are frequently prescribed drugs among women, mainly for their reversible contraceptive purposes but also for beneficial effects in some gynecological pathologies. Despite extensive studies aimed at elucidating the physical effects of hormonal contraceptives and ameliorating some unwanted outcomes, little is known yet about the effects of these drugs on brain function and related behavior, which are known to be modulated by endogenous steroid hormones. We describe the current literature on preclinical studies in animals undertaken to investigate effects of hormonal contraceptives on brain function and behavior. These studies suggest that hormonal contraceptives influence neurohormones, neurotransmitters, neuropeptides, and emotional, cognitive, social and sexual behaviors. Animals allow examination of the basic biological mechanisms of these drugs, devoid of the psychological aspect often associated to hormonal contraceptives' use in women. Understanding the neurobiological effects of these drugs may improve women's health and may help women making informed choices on hormonal contraception.

Hormonal Contraception and the Brain: Examining Cognition and Psychiatric Disorders

Background:

The combined oral contraceptive pill (OC), containing synthetic estrogens and progestins, is used by millions of women worldwide, yet little is known about its effects on cognition or on psychiatric disorders. The progestin component of OCs determines their androgenicity, i.e. whether the OC has androgen binding components with masculinising effects or antiandrogenic components with feminising effects.

Objective:

The present review discusses the literature surrounding OC use and cognition in healthy women. Given the important role that sex hormones play in psychiatric disorders, we also consider the influence of OCs on symptoms of schizophrenia, post-traumatic stress disorder, depression, bipolar disorder, anxiety disorders and indirectly, sleep quality.

Results:

Research has shown that while there are no differences between OC users and non-users, androgenic OCs enhance visuospatial ability and anti-androgenic OCs enhance verbal fluency. Little is known about OCs effects on other cognitive domains, such as memory and executive function. There is little research examining OC use in schizophrenia, post-traumatic stress disorder, bipolar disorder and anxiety disorders. There is some evidence that OC use is associated with depression, however the exact causality of this association remains to be verified.

Conclusion:

We maintain that future studies need to address several methodological limitations, such as separating OCs based on androgenicity to avoid the masking effects that occur when various OCs are considered as one group. As this review highlights several significant effects of OC use on the brain, the implications of OC use needs to be considered in future research.

Sex Differences in Traumatic Brain Injury: What We Know and What We Should Know

There is growing recognition of the problem of male bias in neuroscience research, including in the field of traumatic brain injury (TBI) where fewer women than men are recruited to clinical trials and male rodents have predominantly been used as an experimental injury model. Despite TBI being a leading cause of mortality and disability worldwide, sex differences in pathophysiology and recovery are poorly understood, limiting clinical care and successful drug development. Given growing interest in sex as a biological variable affecting injury outcomes and treatment efficacy, there is a clear need to summarize sex differences in TBI. This scoping review presents an overview of current knowledge of sex differences in TBI and a comparison of human and animal studies. We found that overall, human studies report worse outcomes in women than men, whereas animal studies report better outcomes in females than males. However, closer examination shows that multiple factors including injury severity, sample size, and experimental injury model may differentially interact with sex to affect TBI outcomes. Additionally, we explore how sex differences in mitochondrial structure and function might contribute to possible sex differences in TBI outcomes. We propose recommendations for future investigations of sex differences in TBI, which we hope will lead to improved patient management, prognosis, and translation of therapies from bench to bedside.

A Repeated Measures Pilot Comparison of Trajectories of Fluctuating Endogenous Hormones in Young Women with Traumatic Brain Injury, Healthy Controls

Objective

To compare baseline and 72-hour hormone levels in women with traumatic brain injury (TBI) and controls.

Setting

Hospital emergency department.

Participants

21 women ages 18-35 with TBI and 21 controls.

Design

Repeated measures.

Main Measures

Serum samples at baseline and 72 hours; immunoassays for estradiol (E2), progesterone (PRO), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and cortisol (CORT); and health history.

Results

Women with TBI had lower E2 (p = 0.042) and higher CORT (p = 0.028) levels over time. Lower Glasgow Coma Scale (GSC) and OCs were associated with lower FSH (GCS p = 0.021; OCs p = 0.016) and higher CORT (GCS p = 0.001; OCs p = 0.008).

Conclusion

Acute TBI may suppress E2 and increase CORT in young women. OCs appeared to independently affect CORT and FSH responses. Future work is needed with a larger sample to characterize TBI effects on women's endogenous hormone response to injury and OC use's effects on post-TBI stress response and gonadal function, as well as secondary injury.

Sex Differences in Common Sports Injuries

Common sports injuries include bone stress injuries (BSIs), anterior cruciate ligament (ACL) injuries, and concussions. Less commonly recognized are the specific sex differences in epidemiology, risk factors, and outcomes of these conditions by sex. An understanding of these factors can improve their clinical management, from prescribing appropriate prehabilitation to guiding postinjury rehabilitation and return to play. This narrative review summarizes the sex differences in the diagnosis and management of BSIs, ACL injuries, and concussions. Although BSIs are more common in female athletes, risk factors for both sexes include prior injury and relative energy deficiency in sport (RED-S). Risk factors in female athletes include smaller calf girth, femoral adduction, and higher rates of loading. Female athletes are also at greater risk for developing ACL injuries in high school and college, but their injury rate is similar in professional sports. Increased lateral tibial slope, smaller ACL size, and suboptimal landing mechanics are additional risk factors more often present in female athletes. Male athletes are more likely to have ACL surgery and have a higher rate of return to sport. Concussions occur more commonly in female athletes; however, female athletes are also more likely to report concussions. Male athletes more commonly sustain concussion through contact with another player. Female athletes more commonly sustain injury from contact with playing equipment. Managing post-concussion symptoms is important, and female athletes may have prolonged symptoms. An understanding of the sex-specific differences in these common sports injuries can help optimize their prehabilitation and rehabilitation. LEVEL OF EVIDENCE: IV.

The Effects of Sex Differences and Hormonal Contraception on Outcomes after Collegiate Sports-Related Concussion

There is conflicting evidence regarding whether females are more adversely affected after concussion than males. Further, recent research suggests that hormonal contraceptive (HC) use may affect symptom severity and duration post-concussion. The objective of this study was to examine the effects of sex and HC use on outcomes following concussion among collegiate varsity athletes. We hypothesized that females would have longer length of recovery (LOR), and that peak symptom severity would be associated with longer LOR in both males and females. Among females, we hypothesized that non-HC users would have longer LOR and higher peak symptom severity than HC users. Ninety collegiate student-athletes were included in this study (40 males, 50 females; 24 HC users, 25 non-HC users). Demographic, injury, and recovery information was abstracted via retrospective record review. LOR was defined as days between injury and clearance for full return to play by team physician. Peak symptom severity score (Sport Concussion Assessment Tool [SCAT] 2 or 3) was used in analyses. Study results revealed that males had shorter LOR than females (F[1, 86] = 5.021, p < 0.05, d = 0.49), but had comparable symptom severity scores. Symptom severity was strongly related to LOR for males (r = 0.513, p < 0.01) but not females (r = -0.003, p > 0.05). Among females, non-HC users demonstrated higher symptom severity than HC users (F[1,47] = 5.142, p < 0.05, d = 0.70). No significant differences between female HC users and non-HC users on LOR were observed. This study provides evidence for differential concussion outcomes between male and female collegiate athletes and between HC users and nonusers among females.

Sport Concussion and the Female Athlete

Sport concussion (SC) has emerged as a major health concern in the medical community and general public owing to increased research and media attention, which has primarily focused on male athletes. Female athletes have an equal, if not increased, susceptibility to SC. An ever-growing body of research continues to compare male and female athletes in terms of SC before and after an injury. Clinicians must be cognizant of this literature to make evidence-based clinical decision when providing care to female athletes and discern between dated and/or unsupported claims in terms of SC.

The other side of progestins: effects in the brain

Progestins are a broad class of progestational agents widely differing in their chemical structures and pharmacological properties. Despite emerging data suggest that progestins, besides their action as endometrial protection, can also have multiple nonreproductive functions, much remains to be discovered regarding the actions exerted by these molecules in the nervous system. Here, we report the role exerted by different progestins, currently used for contraception or in postmenopausal hormone replacement therapies, in regulating cognitive functions as well as social behavior and mood. We provide evidence that the effects and mechanisms underlying their actions are still confusing due to the use of different estrogens and progestins as well as different doses, duration of exposure, route of administration, baseline hormonal status and age of treated women. We also discuss the emerging issue concerning the relevant increase of these substances in the environment, able to deeply affect aquatic wildlife as well as to exert a possible influence in humans, which may be exposed to these compounds via contaminated drinking water and seafood. Finally, we report literature data showing the neurobiological action of progestins and in particular their importance during neurodegenerative events. This is extremely interesting, since some of the progestins currently used in clinical practice exert neuroprotective and anti-inflammatory effects in the nervous system, opening new promising opportunities for the use of these molecules as therapeutic agents for trauma and neurodegenerative disorders.

Menstrual phase as predictor of outcome after mild traumatic brain injury in women

OBJECTIVE

To determine whether menstrual cycle phase in women at the time of mild traumatic brain injury (mTBI) predicts 1-month outcomes.

SETTING

Six emergency departments; 5 in Upstate New York, and 1 in Pennsylvania.

PARTICIPANTS

One hundred forty-four female participants (age, 16-60) who presented to participating emergency departments within 4 hours of mTBI.

DESIGN

Nested cohort study with neurologic and quality-of-life outcome assessment, 1 month after enrollment. Female subjects aged 16 to 60 enrolled in the parent cohort study, with 1-month neurological determination data available, were classified into menstrual cycle groups by serum progesterone concentration and self-reported contraceptive use.

MAIN MEASURES

Rivermead Post Concussion Questionnaire and EuroQoL/EQ5D.

RESULTS

Women injured during the luteal phase of their menstrual cycle, when progesterone concentration is high, had significantly lower EuroQoL General Health Ratings and Index Scores than women injured during the follicular phase of their cycle or women taking oral contraceptives. Multivariate analysis confirmed a significant independent effect of menstrual cycle phase on EuroQoL Index Score and the Rivermead Post Concussion Questionnaire Somatic Subscore.

CONCLUSION

Menstrual cycle phase and progesterone concentration at the time of mTBI affect 1-month quality-of-life and neurologic outcomes. This association has important implications for treatment and prognosis after mTBI.

A systematic review of the impact of oral contraceptives on cognition

Combined oral contraceptives (OCs) are the most commonly prescribed medication in women of reproductive age, but despite widespread use, their effect on cognitive performance remains controversial. Given strong evidence for the neurological impact of reproductive hormones, a clear rationale for investigation exists. This systematic review sought to identify, collate and critically appraise studies assessing the impact of OCs on cognition in healthy premenopausal women. Ovid MEDLINE, PsychINFO and EMBASE were comprehensively searched using relevant keywords for original peer-reviewed observational studies or randomised trials published after 1960. Of 1289 references screened, 22 studies were eligible for inclusion. Assembled evidence supports a cognitive impact of OCs restricted to specific domains; however, the quality of evidence is poor. The most consistent finding is improved verbal memory with OC use. Evidence is also emerging that differing progestin androgenicity may lead diverse OC formulations to differentially impact certain cognitive domains, such as visuospatial ability. At present, evidence is inconclusive, contradictory and limited by methodological inconsistencies. There is scope for further research in this area to definitively determine the cognitive impact of OCs.

Relative risk for concussions in young female soccer players

The objective of this study was to determine the relative risk and reported symptoms of concussions in 11- to 13-year-old, female soccer players. For this, a survey to compare the reported incidence of concussion in age-matched female soccer players to nonsoccer players was performed. The survey included 342 girls between the ages of 11 and 13: 195 were involved in an organized soccer team and 147 were not involved in organized soccer but were allowed to participate in any other sport or activity. A total of 94 of the 195 soccer players, or 48%, reported at least one symptom consistent with a concussion. The most prevalent symptom for these girls was headache (84%). A total of 34 of the 147 nonsoccer players, or 23%, reported at least one symptom consistent with a concussion in the previous six months. These results determined that the relative risk of probable concussions among 11- to 13-year-old, female soccer players is 2.09 (p < .001, α = .05, CI = 95%). This demonstrates that the relative risk of probable concussions in young female soccer players is significantly higher than in a control group of nonsoccer players of the same sex and age.

Does an individual's fitness level affect baseline concussion symptoms?

CONTEXT

Variables that may influence baseline concussion symptoms should be investigated.

OBJECTIVE

To evaluate the effect of physical fitness on self-report of baseline concussion symptoms in collegiate athletes and students.

DESIGN

Controlled laboratory study.

PATIENTS OR OTHER PARTICIPANTS

A total of 125 undergraduates, including 95 collegiate athletes and 30 recreational athletes (83 males, 42 females).

INTERVENTION(S)

Participants completed the Standardized Concussion Assessment Tool 2 (SCAT2; symptom report) at baseline, within 10 minutes of completing the Leger test, and within 24 hours of the initial baseline test. The Leger (beep) test is a shuttle-run field test used to predict maximal aerobic power.

MAIN OUTCOME MEASURE(S)

The total symptom score on the SCAT2 was calculated and analyzed with a repeated-measures analysis of variance. A linear regression analysis was used to determine if 3 variables (sport type, sex, or fitness level) accounted for a significant amount of the variance in the baseline symptom report.

RESULTS

Participants reported more symptoms postactivity but fewer symptoms at 24 hours compared with baseline, representing a time effect in our model (F2,234 = 47.738, P < .001). No interactions were seen among the independent variables. We also found an effect for fitness level, with fitter individuals reporting fewer symptoms at all 3 time intervals. The regression analysis revealed that fitness level accounted for a significant amount of the variance in SCAT2 symptoms at baseline (R (2) = 0.22, F3,121 = 11.44, P < .01).

CONCLUSIONS

Fitness level affected the baseline concussion symptom report. Exercise seems to induce concussion symptom reporting, and symptom severity may be a function of an athlete's level of conditioning. Sports medicine professionals should consider an athlete's level of fitness when conducting baseline concussion symptom assessments.

The balance error scoring system learned response among young adults

BACKGROUND

Concussion management practices are important for athlete safety. Baseline testing provides a benchmark to which post-injury assessments are compared. Yet few neurophysical concussion assessment studies have examined learned response. The Balance Error Scoring System (BESS) measures postural stability through 6 conditions by counting the errors committed during each condition. In a study examining the performance of high school-aged athletes on the BESS, the learned response extinguished in 3 weeks. However, this phenomenon has not been studied in the college-aged population.

HYPOTHESIS

College-aged adults performing the BESS will have a learned response at 1 and 2 weeks but would have no change from baseline at or after 3 weeks, as found previously in high school-aged subjects.

STUDY DESIGN

Randomized controlled clinical trial.

METHODS

Three groups of college-aged adults ages 18 to 26 years were tested using the BESS at scheduled intervals. Each subject was randomly assigned into 1 of 3 groups to determine learned response at weeks 1, 2, and 4. Changes in pretest and posttest BESS scores were compared using the paired t test for each group at week 4 and other intervals. Differences among groups were compared using analysis of variance for means or the chi-square test for proportions.

RESULTS

After 4 weeks, participants exhibited a mean (95% confidence interval) change from pretest baseline of -2.30 (-4.75, 0.16) in the control group (P = 0.065), -3.13 (-4.84, -1.41) in Group 1 (P = 0.001), and -2.57 (-5.28, 0.15) in Group 2 (P = 0.063). There were no statistically significant differences between the 3 groups for week 4 BESS score (P = 0.291) or changes from baseline to week 4 BESS scores (P = 0.868). Overall, participant score changes from baseline to the 4-week follow-up still showed a statistically significant or close to significant reduction across the 3 groups, indicating the learned response did not extinguish after 4 weeks.

CONCLUSION

Repeated BESS testing results in a learned effect in college-aged adults did not extinguish after 4 weeks. These results question the ability of the BESS to assess an athlete's balance deficits following a concussion.

CLINICAL RELEVANCE

Given learned response did not extinguish in this sample and the BESS has a minimal detectable change/reliable change index of 7 or greater, the effectiveness of the BESS to assess balance may be limited.