Systematic Review of Sex and Gender Effects in Traumatic Brain Injury: Equity in Clinical and Functional Outcomes

Gender and race in neurotrauma: part 2-underrepresentation in clinical trial enrollment and impact on clinical outcomes

The underrepresentation of women and racial minorities in clinical trials populations remains a persistent challenge across many medical specialties, including Neurosurgery. A diverse research cohort brings varied perspectives and experiences, which can lead to more innovative solutions to medical problems, generalizable findings, and the foundations to provide culturally competent care to the populations most affected by the condition at hand. The importance of representative Neurotrauma trial populations cannot be overstated, as results are essential to inform decision making and gender and race have both been shown to significantly influence patient outcomes, as seen in the traumatic brain injury and spinal cord injury populations. Although the path towards gender and racial parity in clinical trial participants has been slow, numerous actions have been taken, including the FDA Safety and Innovation Act (2012) and Omnibus Reform Act (2022) on a systemic level. In this paper, we aimed to explore the barriers to and implications of inadequate representation in neurotrauma trials to outline a roadmap towards more diverse trial inclusion and retention. Key strategies moving forward include recruiting a diverse research team, developing flexible study protocols that support the varying needs of individuals of different backgrounds, establishing methods of data analysis that control for social and demographic factors instead of excluding individuals from participating, introducing patient navigators, reflecting on systemically engrained biases, implementing mandatory reporting of gender and race data, establishing and analyzing policies that keep researchers accountable towards goals of inclusive recruitment, and identifying and addressing unique barriers that individuals at the intersection of gender and racial minority status face.

Global Burden of Traumatic Brain Injury in 204 Countries and Territories From 1990 to 2021

INTRODUCTION

This study aimed to evaluate the burden and underlying causes of traumatic brain injury (TBI) in 204 countries and territories from 1990 to 2021.

METHODS

Utilizing data from the Global Burden of Disease 2021 study, which derived estimates of TBI burden from hospital and emergency department records, national surveys, and claims data, the incidence, prevalence, and years lived with disability (YLDs) associated with TBI were analyzed. A comparative analysis of TBI burden by location, age, sex, and sociodemographic index was performed, along with an underlying assessment of 15 major causes contributing to age-standardized incidence rates. Analyses were conducted in 2024.

RESULTS

In 2021, there were 20.84 million (95% uncertainty interval [UI]=18.13, 23.84) incident cases and 37.93 million (95% UI=36.33, 39.77) prevalent cases of TBI globally, resulting in 5.48 million (95% UI=3.87, 7.33) YLDs. While the absolute number increased from 1990 to 2021, age-standardized rates of TBI incidence, prevalence, and YLDs showed a significant decline. These rates generally increased with age and were higher in males than females. The highest age-standardized prevalence and YLD rates were observed in Eastern and Central Europe. Globally, falls were the leading cause of TBI in 2021, followed by road injuries, interpersonal violence, and exposure to mechanical forces.

CONCLUSIONS

Despite declines in age-standardized rates, the total number of TBI cases and associated disabilities has risen since 1990, indicating a persistent global burden. Targeted interventions are urgently needed in high-burden regions like Eastern and Central Europe, with focus on leading causes and vulnerable populations.

"Gender matters": the development of infographics to raise awareness and promote gender-transformative care in traumatic brain injury

PURPOSE

To develop a series of infographics providing persons with traumatic brain injury (TBI) and their circle of care with evidence-based information on sex and gender topics in TBI.

MATERIALS AND METHODS

We employed an iterative participatory design engaging knowledge users, scientists, and experts in brain injury and patient education. To inform infographic content, we conducted an information needs assessment with knowledge users through semi-structured interviews and referred to our previously published evidence syntheses on TBI topics. We followed principles of graphic design and science communication to create materials reflecting lived experiences of knowledge users.

RESULTS

We created a series of infographics with actionable messages and visual representations of evidence-based information. We achieved a Flesch Reading-Ease score of 60.1, corresponding to a Grade 7/8 reading level. The infographics met the color contrast criteria of the Web Content Accessibility Guidelines. Knowledge users found the material useful, visually appealing, and helpful in understanding complex topics.

CONCLUSIONS

There is value in merging art and science to develop educational materials that meet the unique information needs of knowledge users. Iterative participatory design engaging diverse stakeholders is essential for co-creating knowledge translation tools to improve access to health information and quality of care after TBI.

Sex differences in electrical activity of the brain during sleep: a systematic review of electroencephalographic findings across the human lifespan

BACKGROUND

With the explosion of techniques for recording electrical brain activity, our recognition of neurodiversity has expanded significantly. Yet, uncertainty exists regarding sex differences in electrical activity during sleep and whether these differences, if any, are associated with social parameters. We synthesised existing evidence applying the PROGRESS-Plus framework, which captures social parameters that may influence brain activity and function.

METHODS

We searched five databases from inception to December 2024, and included English language peer-reviewed research examining sex differences in electrical activity during sleep in healthy participants. We performed risk of bias assessment following recommended criteria for observational studies. We reported results on sex differences by wave frequency (delta, theta, alpha, sigma, beta, and gamma) and waveforms (spindle and sawtooth), positioning results across age-related developmental stages. We created visualizations of results linking study quality and consideration of PROGRESS-Plus parameters, which facilitated certainty assessment.

RESULTS

Of the 2,783 unique citations identified, 28 studies with a total of 3,374 participants (47% male, age range 4-5 months to 101 years) were included in data synthesis. Evidence of high certainty reported no sex differences in alpha and delta relative power among participants in middle-to-late adulthood. Findings of moderate certainty suggest no sex differences in alpha power; and theta, sigma and beta relative power; and delta density. There is evidence of moderate certainty suggesting that female participants had a steeper delta wave slope and male participants had greater normalized delta power. Evidence that female participants have higher spindle power density is of low certainty. All other findings were regarded as very low in certainty. The PROGRESS-Plus parameters were rarely integrated into the methodology of studies included in this review.

CONCLUSION

Evidence on the topic of sex differences in sleep wave parameters is variable. It is possible that the reported results reflect unmeasured social parameters, instead of biological sex. Future research on sex differences in sleep should be discussed in relevance to functional or clinical outcomes. Development of uniform testing procedures across research settings is timely.

PROSPERO

CRD42022327644.

FUNDING

Canada Research Chairs (Neurological Disorders and Brain Health, CRC-2021-00074); UK Pilot Award for Global Brain Health Leaders (GBHI ALZ UK-23-971123).

Complications After Maternal Traumatic Brain Injury During Pregnancy: A Systematic Review

Importance

General trauma is the leading cause of nonobstetric maternal morbidity and mortality, affecting approximately 8% of all pregnancies. Pregnant women with traumatic brain injury (TBI) face high morbidity and mortality rates, requiring complex management due to physiological changes, teratogenic risks of treatments, and the need for fetal monitoring.

Objectives

To assess the consequences of TBI during pregnancy on maternal and fetal outcomes and to evaluate management strategies to inform clinical decision-making.

Evidence Review

A systematic literature search was conducted on January 12, 2024, in PubMed, Web of Science, and PsycInfo to identify articles published in English, German, or Spanish between January 1, 1990, and December 31, 2023, that included at least 1 pregnant individual with TBI. Peer-reviewed, human-based studies with original data on maternal and fetal outcomes were included. Reviews, meta-analyses, and nonhuman studies were excluded. Two independent reviewers screened abstracts and full-text articles. Study characteristics, pregnancy outcomes (maternal and fetal), management methods, and authors' conclusions were extracted. Risk of bias was assessed by 2 reviewers, with interrater agreement measured using Cohen κ. Disagreements were resolved through discussion. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline was followed.

Findings

This systematic review included 16 articles involving a total of 4112 individuals (mean maternal age, 26.9 years; range, 16-47 years) who experienced TBI during pregnancy (mean gestational age at injury, 24 weeks; range, 3-38 weeks). The articles comprised 10 case reports, 2 case series, and 4 cohort studies. Motor vehicle crashes were the most common cause of injury, reported in 12 articles. The average Glasgow Coma Scale score ranged from 3 to 15 across all individuals. Conservative management was reported in 7 case patients, whereas surgery was performed in 6 case patients. Maternal outcomes ranged from functional recovery to severe cognitive impairment, and fetal outcomes varied from stable to severe adverse outcomes, including stillbirth and death. Risk of bias assessment indicated moderate to good methodological validity overall, but most articles demonstrated poor quality of evidence.

Conclusions and Relevance

In this review, no definitive association between TBI during pregnancy and maternal or fetal outcomes was found owing to conflicting findings, poor to moderate study quality, and limited evidence. Although some articles suggested increased risks such as placental abruption and cesarean delivery, the findings remained inconclusive. The findings of this review underscore the need for high-quality research, standardized reporting, and rigorous methodology to improve data reliability. Future research should focus on developing consensus-driven, multidisciplinary management strategies to improve maternal and fetal outcomes.

A Directed Content Analysis for Greatest Problems Among People With and Without Traumatic Brain Injury

OBJECTIVE

To characterize the greatest problem or need among individuals with a history of traumatic brain injury (TBI), as compared with individuals with a history of other neurologic conditions, mental health conditions, and no history of neurologic or mental health conditions.

DESIGN

A directed content analysis of open-text responses to a single online survey question using a framework guided by the Mayo-Portland Adaptability Inventory-4.

SETTING

Community.

PARTICIPANTS

A total of 2861 community-dwelling adults (n=274 with TBI; n=289 with other neurologic conditions besides TBI; n=454 with mental health conditions but no neurologic conditions; and n=1844 controls).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Open-text responses to the survey prompt: "What was your greatest problem or need over the past 2 weeks?"

RESULTS

The Participation index comprised the greatest proportion of responses across all 4 participant groups. A quarter (25.4%) of controls reported None (no problem/need), whereas only 7.9%-10.7% of participants in all other groups reported None. Among all groups, individuals with TBI reported the greatest proportion of problems in the Adjustment and Ability indices. Among people with TBI, Money Management (19.7%), None (10.6%), and Anxiety (7.7%) were the 3 most frequently reported problems. Compared with individuals with mild TBI (mTBI), individuals with moderate-to-severe TBI (msTBI) reported a higher proportion of problems in the Ability and Adjustment indices. Among individuals with msTBI, the Adjustment index accounted for the greatest proportion of problems.

CONCLUSIONS

This study employed a person-centered approach to understanding the greatest needs among individuals with TBI. Qualitative differences were observed between individuals with and without TBI, between people with mTBI and msTBI, and across genders among people with TBI. These findings can help guide research and policy toward addressing challenges perceived as highly important by people living in the community with TBI.

Assessment of the sentiments expressed by traumatic brain injury patients and caregivers: A qualitative study based on in-depth interviews

Introduction

Traumatic Brain Injury (TBI) is a significant public health concern that causes death, disability, and economic burden. Its repercussions affect physical, cognitive, emotional, and behavioral aspects of long-term care needs. Despite improvements in communication among multidisciplinary teams, the management of TBI remains fragmented.

Objective

This study aimed to assess patients and caregivers' experiences through sentiment analysis.

Materials and methods

A qualitative cross-sectional study utilized structured topic modeling (STM) to analyze in-depth interview data. The study involved 29 patients with TBI and 27 caregivers in Madrid (Spain), using a survey design. The interviews were conducted, transcribed, and coded independently over 5 months. Sentiments such as anticipation, fear, and emotional concerns were analyzed using three dictionaries. The STM analysis identified four key concepts: desire for independence, potential improvement, need for injury information, and psychological consequences. STM diagnostic graphs were used to determine the number of topics relevant to the evaluation of patient and caregiver concerns. Furthermore, an analysis was conducted across four topics.

Results

The average age of the patients was 44.2 ± 14.9 years (69 % males). Regarding TBI severity, 59 % of patients had severe TBI, whereas the remaining 41 % had experienced moderate TBI. Among the caregivers, the majority were parents (30 %), partners (24 %), or siblings (24 % each). Among the 51 participants, sentiments were analyzed using three dictionaries. While there were no significant age differences (Z = 0.24, p = 0.815), the STM model was adjusted for significant sex differences (p = 0.017) between patients and relatives. Anticipation and fear prevailed in both groups, highlighting the shared emotional patterns.

Discussion

The analysis of diagnostic graphs indicated the optimal number of topics for evaluation, emphasizing key concerns across different phases of TBI. Patients' main worries shifted from physical symptoms to limitations in daily life and independence. Caregivers highlighted the importance of staff interactions, misinformation challenges, and the need for psychological care.

Conclusion

Key patient concerns, including dependency on daily activities, limitations in autonomy, and caregiver burden, emphasize crucial areas for enhancement in multidisciplinary treatment. Moreover, the lack of long-term psychological support is a significant barrier to optimal patient and caregiver well-being.

"A whole ball of all-togetherness": The interwoven experiences of intimate partner violence, brain injury, and mental health

BACKGROUND

Intimate partner violence (IPV) is a global public health crisis, with physical violence leaving IPV survivors at high risk of brain injury (BI). Both BI and IPV have significant physical, psychological, cognitive, and social impacts, including a high risk of mental health concerns, yet there is limited exploration of IPV survivors' experiences with BI and mental health. This study aimed to explore the BI- and mental health-related needs and experiences of IPV survivors from the perspectives of survivors and service providers with the objective of developing knowledge translation materials to raise awareness and support survivors and service providers in addressing these concerns.

METHODS

This qualitative interpretive description study involved 19 semi-structured interviews and two focus group discussions (2-3 participants each) with 24 participants including IPV survivors experiencing BI and mental health concerns as well as IPV, mental health, and BI service providers between October 2020 and February 2021. Three screening questions were used to identify probable BI among survivors. Participants across groups were an average of 48.5±12.7 years old and were predominantly cisgender women (96%), of European origin (75%), with a university degree (71%). Interviews were recorded, transcribed, and thematically analyzed.

FINDINGS

Across interviews, participants spoke about IPV, BI, and mental health as being complex and interrelated experiences that have impacts across the survivor's life and extend well beyond the abusive relationship. Because of the underrecognized nature of BI in IPV, finding and accessing care requires persistence that survivors spoke of as being like "a full-time job." The benefit of making meaningful connections, particularly with other survivors, was highlighted.

CONCLUSIONS

Recognition of BI as a contributing factor shaping the lived experience of IPV survivors; acknowledgement that the impacts of IPV, BI, and mental health are far reaching and long lasting; and reducing barriers to finding and accessing appropriate care are critical to better supporting IPV survivors with BI and mental health concerns. Clinicians should consider BI and its lingering impacts among the IPV survivors with whom they work. Health and social policy that supports integration of care and the reduction of unnecessary barriers should be a priority.

Traumatic brain injury and long-term associations with work, divorce and academic achievement

OBJECTIVE

Traumatic brain injuries (TBI), irrespective of severity, may have long-term social implications. This study explores the relationships between TBI severity and outcomes related to work stability, divorce, and academic achievement.

METHODS

Using a Danish nationwide sample of persons with and without TBI, we employed case-control and longitudinal cohort designs. The case-control design utilized individuals aged 18 to 60 years and examined work stability. Each case, employed at time of TBI, was compared with 10 matched controls. The cohort design utilized individuals alive from 1980 to 2016 with and without TBI and assessed the likelihood of 1) divorce and 2) higher-level education. TBI exposures included concussion, skull fractures, or confirmed TBI.

RESULTS

TBI cases exhibited higher odds ratios (OR) for work instability at all follow-ups compared to controls. Increased TBI severity was associated with a higher risk of work instability at 2-year follow-up (concussion: OR = 1.83; skull fracture: OR = 2.22; confirmed TBI: OR = 4.55), and with a higher risk of not working at 10-year follow-up (confirmed TBI: OR = 2.82; concussion: OR = 1.63). The divorce incidence rate ratio (IRR) was elevated in individuals with TBI (males: IRR = 1.52; females: IRR = 1.48) compared to those without TBI. Individuals with childhood TBI had reduced chances of attaining high school degree or higher (males: IRR = 0.79; females: IRR = 0.85) compared to those without TBI.

CONCLUSION

TBI is associated with an increased long-term risk of social consequences, including work instability, divorce, and diminished chances of higher education, even in cases with concussion.

A PROGRESS-driven approach to cognitive outcomes after traumatic brain injury: A study protocol for advancing equity, diversity, and inclusion through knowledge synthesis and mobilization

Evidence syntheses for advancing equitable traumatic brain injury (TBI) research, policy, and practice presents formidable challenges. Research and clinical frameworks are currently not specific to equity, diversity, and inclusion considerations, despite evidence that persons with TBI live in societies in which power imbalances and systems of social dominance may privilege some people and marginalize others. The present protocol outlines a strategy for a research program, supported by the Canadian Institutes of Health Research, that explores the integration of PROGRESS-Plus parameters in research with the goal of advancing open-science databases and tools to improve our understanding of equity in cognitive and brain health outcomes in TBI. PROGRESS-Plus is a framework outlining social, economic, and cultural parameters that may influence health opportunities and outcomes (e.g., place of residence, race, occupation, gender, etc.). A multistep research program is proposed to support three objectives: (1) organizing existing data on TBI-induced changes in cognition and brain health into a template to facilitate future research, including research using machine learning techniques; (2) updating published evidence with a more rigorous approach to the consideration of PROGRESS-Plus parameters; and (3) mobilizing knowledge on the current state of evidence that is relevant, equitable, and accessible. This program facilitates partnerships with knowledge users across clinical, research, academic, and community sectors to address the three research objectives through a unifying workflow of exchange, synthesis, and knowledge mobilization. We anticipate that this global collaboration between topic experts and community leaders in equity in brain health will add significant value to the field of TBI by promoting equity-transformative advancements in knowledge synthesis, policy, and practice.

The Australian Traumatic Brain Injury Initiative: Systematic Review and Consensus Process to Determine the Predictive Value of Demographic, Injury Event, and Social Characteristics on Outcomes for People With Moderate-Severe Traumatic Brain Injury

The objective of the Australian Traumatic Brain Injury (AUS-TBI) Initiative is to develop a data dictionary to inform data collection and facilitate prediction of outcomes of people who experience moderate-severe TBI in Australia. The aim of this systematic review was to summarize the evidence of the association between demographic, injury event, and social characteristics with outcomes, in people with moderate-severe TBI, to identify potentially predictive indicators. Standardized searches were implemented across bibliographic databases to March 31, 2022. English-language reports, excluding case series, which evaluated the association between demographic, injury event, and social characteristics, and any clinical outcome in at least 10 patients with moderate-severe TBI were included. Abstracts and full text records were independently screened by at least two reviewers in Covidence. A pre-defined algorithm was used to assign a judgement of predictive value to each observed association. The review findings were discussed with an expert panel to determine the feasibility of incorporation of routine measurement into standard care. The search strategy retrieved 16,685 records; 867 full-length records were screened, and 111 studies included. Twenty-two predictors of 32 different outcomes were identified; 7 were classified as high-level (age, sex, ethnicity, employment, insurance, education, and living situation at the time of injury). After discussion with an expert consensus group, 15 were recommended for inclusion in the data dictionary. This review identified numerous predictors capable of enabling early identification of those at risk for poor outcomes and improved personalization of care through inclusion in routine data collection.

Clinical practice guideline recommendations to improve the mental health of adult trauma patients: protocol for a systematic review

INTRODUCTION

Mental disorders are common in adult patients with traumatic injuries. To limit the burden of poor psychological well-being in this population, recognised authorities have issued recommendations through clinical practice guidelines (CPGs). However, the uptake of evidence-based recommendations to improve the mental health of trauma patients has been low until recently. This may be explained by the complexity of optimising mental health practices and interpretating CGPs scope and quality. Our aim is to systematically review CPG mental health recommendations in the context of trauma care and appraise their quality.

METHODS AND ANALYSIS

We will identify CPG through a search strategy applied to Medline, Embase, CINAHL, PsycINFO and Web of Science databases, as well as guidelines repositories and websites of trauma associations. We will target CPGs on adult and acute trauma populations including at least one recommendation on any prevention, screening, assessment, intervention, patient and family engagement, referral or follow-up procedure related to mental health endorsed by recognised organisations in high-income countries. No language limitations will be applied, and we will limit the search to the last 15 years. Pairs of reviewers will independently screen titles, abstracts, full texts, and carry out data extraction and quality assessment of CPGs using the Appraisal of Guidelines Research and Evaluation (AGREE) II. We will synthesise the evidence on recommendations for CPGs rated as moderate or high quality using a matrix based on the Grading of Recommendations Assessment, Development and Evaluation quality of evidence, strength of recommendation, health and social determinants and whether recommendations were made using a population-based approach.

ETHICS AND DISSEMINATION

Ethics approval is not required, as we will conduct secondary analysis of published data. The results will be disseminated in a peer-reviewed journal, at international and national scientific meetings. Accessible summary will be distributed to interested parties through professional, healthcare quality and persons with lived experience associations. PROSPERO REGISTRATION NUMBER: (ID454728).

Cognitive impairment in Chinese traumatic brain injury patients: from challenge to future perspectives

Traumatic Brain Injury (TBI) is a prevalent form of neurological damage that may induce varying degrees of cognitive dysfunction in patients, consequently impacting their quality of life and social functioning. This article provides a mini review of the epidemiology in Chinese TBI patients and etiology of cognitive impairment. It analyzes the risk factors of cognitive impairment, discusses current management strategies for cognitive dysfunction in Chinese TBI patients, and summarizes the strengths and limitations of primary testing tools for TBI-related cognitive functions. Furthermore, the article offers a prospective analysis of future challenges and opportunities. Its objective is to contribute as a reference for the prevention and management of cognitive dysfunction in Chinese TBI patients.

Neuroprotection or Sex Bias: A Protective Response to Traumatic Brain Injury in the Females

Traumatic brain injury (TBI) is a major healthcare problem and a common cause of mortality and morbidity. Clinical and preclinical research suggests sex-related differences in short- and longterm outcomes following TBI; however, males have been the main focus of TBI research. Females show a protective response against TBI. Female animals in preclinical studies and women in clinical trials have shown comparatively better outcomes against mild, moderate, or severe TBI. This reflects a favorable protective nature of the females compared to the males, primarily attributed to various protective mechanisms that provide better prognosis and recovery in the females after TBI. Understanding the sex difference in the TBI pathophysiology and the underlying mechanisms remains an elusive goal. In this review, we provide insights into various mechanisms related to the anatomical, physiological, hormonal, enzymatic, inflammatory, oxidative, genetic, or mitochondrial basis that support the protective nature of females compared to males. Furthermore, we sought to outline the evidence of multiple biomarkers that are highly potential in the investigation of TBI's prognosis, pathophysiology, and treatment and which can serve as objective measures and novel targets for individualized therapeutic interventions in TBI treatment. Implementations from this review are important for the understanding of the effect of sex on TBI outcomes and possible mechanisms behind the favorable response in females. It also emphasizes the critical need to include females as a biological variable and in sufficient numbers in future TBI studies.

The prevalence of persistent post-traumatic headache in adult civilian traumatic brain injury: a systematic review and meta-analysis on the past 14 years

ABSTRACT

The most recent prevalence estimate of post-traumatic headache (PTH) after traumatic brain injury (TBI) in veterans and civilians dates back to 2008. The prevalence was found to be 57.8%, with surprising higher rates (75.3%) in mild TBI when compared with those with moderate/severe TBI (32.1%). However, the revision of mild TBI diagnostic criteria and an historic peak of TBI in the elderly individuals attributed to the ageing population may lead to different results. Thus, we conducted a systematic review and meta-analysis to assess the updated prevalence of PTH during the past 14 years only in civilians. A literature search was conducted following PRISMA guidelines guided by a librarian. Screening, full-text assessment, data extraction, and risk of bias assessment were performed blindly by 2 raters. Meta-analysis of proportions using the Freeman and Tukey double arcsine method of transformation was conducted. Heterogeneity, sensitivity analysis, and meta-regressions were performed with the predictors: year of publication, mean age, sex, TBI severity, and study design. Sixteen studies were selected for the qualitative analysis and 10 for the meta-analysis. The overall prevalence estimate of PTH was 47.1%, (confidence interval = 34.6, 59.8, prediction intervals = 10.8, 85.4), being similar at different time points (3, 6, 12, and 36+ months). Heterogeneity was high, and none of the meta-regressions were significant. The overall prevalence of PTH after TBI over the past 14 years remains high even if assessed only in civilians. However, the prevalence rates attributed to mild and moderate/severe TBI were similar, differing significantly from previous reports. Efforts are needed to improve TBI outcomes.

Gender versus sex in predicting outcomes of traumatic brain injury: a cohort study utilizing large administrative databases

Understanding the factors associated with elevated risks and adverse consequences of traumatic brain injury (TBI) is an integral part of developing preventive measures for TBI. Brain injury outcomes differ based on one's sex (biological characteristics) and gender (social characteristics reflecting norms and relationships), however, whether it is sex or gender that drives differences in early (30-day) mortality and discharge location post-TBI is not well understood. In the absence of a gender variable in existing data, we developed a method for "measuring gender" in 276,812 residents of Ontario, Canada who entered the emergency department and acute care hospitals with a TBI diagnostic code between April 1st, 2002, and March 31st, 2020. We applied logistic regression to analyse differences in diagnostic codes between the sexes and to derive a gender score that reflected social dimensions. We used the derived gender score along with a sex variable to demonstrate how it can be used to separate the relationship between sex, gender and TBI outcomes after severe TBI. Sex had a significant effect on early mortality after severe TBI with a rate ratio (95% confidence interval (CI)) of 1.54 (1.24-1.91). Gender had a more significant effect than sex on discharge location. A person expressing more "woman-like" characteristics had lower odds of being discharged to rehabilitation versus home with odds ratio (95% CI) of 0.54 (0.32-0.88). The method we propose offers an opportunity to measure a gender effect independently of sex on TBI outcomes.

Bumetanide induces post-traumatic microglia-interneuron contact to promote neurogenesis and recovery

Although the Na-K-Cl cotransporter (NKCC1) inhibitor bumetanide has prominent positive effects on the pathophysiology of many neurological disorders, the mechanism of action is obscure. Attention paid to elucidating the role of Nkcc1 has mainly been focused on neurons, but recent single cell mRNA sequencing analysis has demonstrated that the major cellular populations expressing NKCC1 in the cortex are non-neuronal. We used a combination of conditional transgenic animals, in vivo electrophysiology, two-photon imaging, cognitive behavioural tests and flow cytometry to investigate the role of Nkcc1 inhibition by bumetanide in a mouse model of controlled cortical impact (CCI). Here, we found that bumetanide rescues parvalbumin-positive interneurons by increasing interneuron-microglia contacts shortly after injury. The longitudinal phenotypic changes in microglia were significantly modified by bumetanide, including an increase in the expression of microglial-derived BDNF. These effects were accompanied by the prevention of CCI-induced decrease in hippocampal neurogenesis. Treatment with bumetanide during the first week post-CCI resulted in significant recovery of working and episodic memory as well as changes in theta band oscillations 1 month later. These results disclose a novel mechanism for the neuroprotective action of bumetanide mediated by an acceleration of microglial activation dynamics that leads to an increase in parvalbumin interneuron survival following CCI, possibly resulting from increased microglial BDNF expression and contact with interneurons. Salvage of interneurons may normalize ambient GABA, resulting in the preservation of adult neurogenesis processes as well as contributing to bumetanide-mediated improvement of cognitive performance.

An educational intervention to promote a culture of gender equity among persons with traumatic brain injury and caregivers: A pilot study

BACKGROUND

Traumatic brain injury (TBI) outcomes are dependent on patients' biological sex (e.g., hormone levels) and sociocultural gender (e.g., norms, responsibilities). Informal caregivers additionally experience disruptions to identity and roles post-TBI. However, information on this topic remains largely unavailable to patients and caregivers.

PURPOSE

This study aimed to determine the effectiveness of a one-time educational intervention on sex and gender influences in TBI for patients and informal caregivers.

MATERIALS AND METHODS

We conducted a pilot pre-test/post-test randomized control-group design study. Groups (i.e., passive, active and control) consisted a total of 16 persons with TBI and caregivers (75% persons with TBI, 63% women). Individual and group learning gains, and group-average normalized gain, were computed for three learning domains: knowledge, attitude, and skill. An intervention with an average normalized gain of ≥30% was considered effective. Educational intervention evaluation and qualitative comments post-participation were summarized.

RESULTS

The passive group demonstrated the highest average normalized gain across the three learning domains, including 100% for knowledge, 40% and 61% for attitude, and 37% for skill. The remaining groups did not reach an average normalized gain of ≥30%, except for the attitude domain of the control group (33% and 32%). Two key categories were identified qualitatively: (1) gendered self-expectations post-injury and (2) implications of gender stereotypes in rehabilitation, including the need for rehabilitation treatment to look beyond sex and gender. The post-participation educational session evaluation conveyed high appraisal of content, organization, and usability of the intervention.

CONCLUSION

A one-time passive educational intervention on sex and gender in TBI may improve knowledge, attitude, and skill on the topic of sex and gender among adults with TBI and caregivers. Obtaining knowledge and skill on sex and gender effects in TBI can potentially help persons with TBI and caregivers adapt to changes in roles and behaviours post-injury.

Gender versus sex in predicting outcomes of traumatic brain injury: A cohort study utilizing large administrative databases

Understanding the factors associated with elevated risks and adverse consequences of traumatic brain injury (TBI) is an integral part of developing preventive measures for TBI. Brain injury outcomes differ based on one's sex (biological characteristics) and gender (social characteristics reflecting norms and relationships), however, whether it is sex or gender that drives differences in early (30-day) mortality and discharge location post-TBI event are unknown. In the absence of gender variable in existing data, we developed a method for "measuring gender" in 276,812 residents of Ontario, Canada who entered the emergency department and acute care hospitals with a TBI diagnostic code between April 1st, 2002 and March 31st, 2020. We analysed differences in diagnostic codes between the sexes to derive gender score that reflected social dimensions. Sex had a significant effect on early mortality after severe TBI with a rate ratio (95% confidence interval (CI)) of 1.54 (1.24-1.91). Gender had a more significant effect than sex on discharge location. A person expressing more female-like characteristics have lower odds of being discharged to rehabilitation versus home with odds ratio (95% CI) of 0.54 (0.32-0.88). The method we propose offers an opportunity to measure gender effect independently of sex on TBI outcomes.

Drosophila melanogaster as a model to study age and sex differences in brain injury and neurodegeneration after mild head trauma

Repetitive physical insults to the head, including those that elicit mild traumatic brain injury (mTBI), are a known risk factor for a variety of neurodegenerative conditions including Alzheimer's disease (AD), Parkinson's disease (PD), and chronic traumatic encephalopathy (CTE). Although most individuals who sustain mTBI typically achieve a seemingly full recovery within a few weeks, a subset experience delayed-onset symptoms later in life. As most mTBI research has focused on the acute phase of injury, there is an incomplete understanding of mechanisms related to the late-life emergence of neurodegeneration after early exposure to mild head trauma. The recent adoption of Drosophila-based brain injury models provides several unique advantages over existing preclinical animal models, including a tractable framework amenable to high-throughput assays and short relative lifespan conducive to lifelong mechanistic investigation. The use of flies also provides an opportunity to investigate important risk factors associated with neurodegenerative conditions, specifically age and sex. In this review, we survey current literature that examines age and sex as contributing factors to head trauma-mediated neurodegeneration in humans and preclinical models, including mammalian and Drosophila models. We discuss similarities and disparities between human and fly in aging, sex differences, and pathophysiology. Finally, we highlight Drosophila as an effective tool for investigating mechanisms underlying head trauma-induced neurodegeneration and for identifying therapeutic targets for treatment and recovery.

Nutritional interventions to support acute mTBI recovery

When mild traumatic brain injury (mTBI) occurs following an impact on the head or body, the brain is disrupted leading to a series of metabolic events that may alter the brain's ability to function and repair itself. These changes may place increased nutritional demands on the body. Little is known on whether nutritional interventions are safe for patients to implement post mTBI and whether they may improve recovery outcomes. To address this knowledge gap, we conducted a systematic review to determine what nutritional interventions have been prescribed to humans diagnosed with mTBI during its acute period (<14 days) to support, facilitate, and result in measured recovery outcomes.

Methods

Databases CINAHL, PubMed, SPORTDiscus, Web of Science, and the Cochrane Library were searched from inception until January 6, 2021; 4,848 studies were identified. After removing duplicates and applying the inclusion and exclusion criteria, this systematic review included 11 full papers.

Results

Patients that consumed enough food to meet calorie and macronutrient (protein) needs specific to their injury severity and sex within 96 h post mTBI had a reduced length of stay in hospital. In addition, patients receiving nutrients and non-nutrient support within 24-96 h post mTBI had positive recovery outcomes. These interventions included omega-3 fatty acids (DHA and EPA), vitamin D, mineral magnesium oxide, amino acid derivative N-acetyl cysteine, hyperosmolar sodium lactate, and nootropic cerebrolysin demonstrated positive recovery outcomes, such as symptom resolution, improved cognitive function, and replenished nutrient deficiencies (vitamin D) for patients post mTBI.

Conclusion

Our findings suggest that nutrition plays a positive role during acute mTBI recovery. Following mTBI, patient needs are unique, and this review presents the potential for certain nutritional therapies to support the brain in recovery, specifically omega-3 fatty acids. However, due to the heterogenicity nature of the studies available at present, it is not possible to make definitive recommendations.

Systematic review registration

The systematic review conducted following the PRISMA guidelines protocol was registered (CRD42021226819), on Prospero.

Sex discrimination after injury: is inequity in tranexamic acid administration just the tip of the iceberg?

There is emerging evidence of inequalities in healthcare provision between women and men. Trauma care is no exception with a number of studies indicating lower levels of prioritisation for injured female patients. The antifibrinolytic drug tranexamic acid, reduced trauma deaths to a similar extent in females and males in the international Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH) randomised controlled trials, but in real-world practice, national registry data shows females are less likely to receive tranexamic acid than males. Inequity in the provision of tranexamic acid may extend beyond sex (and gender), and further study is required to examine the effect of age and mechanism of injury differences between men and women in the decision to treat.

Synthesizing sex and gender inequities in traumatic brain injury to catalyze inclusive policy and health services initiatives

Biological and socio-cultural factors are known to impact health outcomes in traumatic brain injury (TBI). Disentangling their role requires both preclinical studies, investigating the mechanistic basis for differential outcomes, and a more diverse pool of clinical and behavioral data from affected individuals. Tailored approaches are essential to enhancing equity in TBI outcomes.

Sex-specific analysis of traumatic brain injury events: applying computational and data visualization techniques to inform prevention and management

BACKGROUND

The interplay of host, agent, and environment implicated in traumatic brain injury (TBI) events is difficult to account for in hypothesis-driven research. Data-driven analysis of injury data can enable insight into injury events in novel ways. This research dissected complex and multidimensional data at the time of the TBI event by exploiting data mining and information visualization methods.

METHODS

We drew upon population-based decade-long health administrative data collected through the routine operation of the publicly funded health system in Ontario, Canada. We applied a computational approach to categorize health records of 235,003 patients with TBI versus the same number of reference patients without TBI, individually matched based on sex, age, place of residence, and neighbourhood income quantile. We adopted the basic concepts of the Haddon Matrix (host, agent, environment) to organize emerging factors significantly related to TBI versus non-TBI events. To explore sex differences, the data of male and female patients with TBI were plotted on heatmaps and clustered using hierarchical clustering algorithms.

RESULTS

Based on detected similarities, the computational technique yielded 34 factors on which individual TBI-event codes were loaded, allowing observation of a set of definable patterns within the host, the agent, and the environment. Differences in the patterns of host, agent and environment were found between male and female patients with TBI, which are currently not identified based on data from injury surveillance databases. The results were internally validated.

CONCLUSIONS

The study outlines novel areas for research relevant to TBI and offers insight into how computational and visual techniques can be applied to advance the understanding of TBI event. Results highlight unique aspects of sex differences of the host and agent at the injury event, as well as differences in exposure to adverse social and environmental circumstances, which can be a function of gender, aiding in future studies of injury prevention and gender-transformative care.