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

Traumatic brain injury: Bridging pathophysiological insights and precision treatment strategies

Blood-brain barrier disruption and the neuroinflammatory response are significant pathological features that critically influence disease progression and treatment outcomes. This review systematically analyzes the current understanding of the bidirectional relationship between blood-brain barrier disruption and neuroinflammation in traumatic brain injury, along with emerging combination therapeutic strategies. Literature review indicates that blood-brain barrier disruption and neuroinflammatory responses are key pathological features following traumatic brain injury. In the acute phase after traumatic brain injury, the pathological characteristics include primary blood-brain barrier disruption and the activation of inflammatory cascades. In the subacute phase, the pathological features are characterized by repair mechanisms and inflammatory modulation. In the chronic phase, the pathological features show persistent low-grade inflammation and incomplete recovery of the blood-brain barrier. Various physiological changes, such as structural alterations of the blood-brain barrier, inflammatory cascades, and extracellular matrix remodeling, interact with each other and are influenced by genetic, age, sex, and environmental factors. The dynamic balance between blood-brain barrier permeability and neuroinflammation is regulated by hormones, particularly sex hormones and stress-related hormones. Additionally, the role of gastrointestinal hormones is receiving increasing attention. Current treatment strategies for traumatic brain injury include various methods such as conventional drug combinations, multimodality neuromonitoring, hyperbaric oxygen therapy, and non-invasive brain stimulation. Artificial intelligence also shows potential in treatment decision-making and personalized therapy. Emerging sequential combination strategies and precision medicine approaches can help improve treatment outcomes; however, challenges remain, such as inadequate research on the mechanisms of the chronic phase traumatic brain injury and difficulties with technology integration. Future research on traumatic brain injury should focus on personalized treatment strategies, the standardization of techniques, cost-effectiveness evaluations, and addressing the needs of patients with comorbidities. A multidisciplinary approach should be used to enhance treatment and improve patient outcomes.

Self-Reported Health Care Disparities and Barriers Among LGBTQIA+ Individuals: Implications for Equitable Health Care Delivery

BACKGROUND AND OBJECTIVES

Nearly 24 million adults in the United States identify as LGBTQIA+, facing significant health disparities due to discrimination, structural barriers, and lack of culturally competent health care. This study explores health care disparities, barriers, facilitators, and the association of perceived discrimination on LGBTQIA+ health care.

METHODS

Participants were recruited from June 2023 to January 2024 using convenience sampling methods via LGBTQIA+ organizations and social media platforms. A total of 501 participants completed a REDCap survey, with 255 providing complete data. The survey queried demographics, physical and mental health, and health care utilization. Data analysis included descriptive statistics and CHERRIES guidelines.

RESULTS

Participants reported significant barriers to care, including being uninsured (22%), geographic distance (33%), fear of negative reactions (26%), and past trauma (23%). Discrimination in health care settings was reported by 83%, impacting access. High rates of homelessness (26%), food insecurity (73%), and chronic medical conditions (92%) were reported. Approximately 55% reported head trauma, 26% experienced intimate partner violence-related head injuries, and only 44% sought care for head injuries. Moderate depressive and anxiety symptoms were common, and 49% screened positive for possible PTSD.

CONCLUSIONS

This study highlights barriers to care reported by LGBTQIA+ individuals, emphasizing the need for culturally informed services. Addressing these disparities requires education, cultural humility, and systemic reforms to reduce disparities in health care for LGBTQIA+ individuals.

Incidence and mortality related risk factors in patients with severe traumatic brain injury: A meta‑analysis

The present study aimed to clarify the onset of traumatic brain injury (TBI) and identify mortality-related risk factors in patients with severe TBI, to enable the early identification of high-risk individuals and timely implementation of prevention and treatment strategies to minimize mortality rates. Comprehensive database searches were conducted across Web of Science, PubMed, CINAHL and EMBASE, covering publications from database inception until October 17, 2023. Search terms in English included 'head trauma', 'brain trauma', 'mortality', 'death' and 'risk factor'. In total, two independent researchers screened and extracted the data on mortality onset and associated risk factors in patients with severe TBI. Meta-analysis was performed using R 4.2.2. A total of 33 cohort studies, including 71,718 patients with severe TBI, were selected for meta-analysis. The data indicated an overall mortality rate of 27.8% (95%CI: 22.5-33.2%) from database inception until October 17, 2023. Subgroup analysis revealed a mortality rate of 25.2% (95%CI: 20.2-30.1%) in developed countries, compared with 38.0% (95%CI: 21.4-54.7%) in developing countries. Additionally, the mean age of deceased patients was significantly higher compared with that of survivors (41.53±16.47). Key risk factors found to be associated with mortality included anemia [relative risk (RR), 1.42; 95%CI, 1.04-1.93], diabetes mellitus (RR, 1.40; 95%CI, 1.00-1.96), coagulopathy (RR, 4.31; 95%CI, 2.31-8.05), shock (RR, 3.41; 95%CI, 2.31-5.04) and systolic blood pressure≤90 mmHg (RR, 2.32; 95%CI, 1.65-3.27). Furthermore, pre-hospital intubation (RR, 1.48; 95%CI, 1.13-1.92),hypotension (RR, 2.04; 95%CI: 1.58, 2.63), hypoxemia (RR, 1.42; 95%CI: 1.13, 1.79), subdural hemorrhage (RR, 1.99; 95%CI: 1.50, 2.62), subarachnoid hemorrhage (RR, 1.64; 95%CI: 1.09, 2.47) and subdural hematoma (SDH; RR, 1.50; 95%CI: 1.04, 2.17). was identified to be a significant risk factor during hospitalization treatment. These results suggest that various factors, such as age, anemia, diabetes, shock, hypotension, hypoxemia, trauma scores and brain injury types, can all contribute to mortality risk in patients with severe TBI. Addressing these risk factors will likely be important for reducing mortality in this patient population.

Status of cerebrovascular autoregulation relates to outcome in severe paediatric head injury: STARSHIP, a prospective multicentre validation study

Background

Continuous assessment of cerebral autoregulation (CA) using pressure reactivity index (PRx), is a promising tool for individualized management to improve outcome after traumatic brain injury (TBI). However, experience with CA in paediatric TBI (pTBI) is limited to retrospective or single-centre studies.

Methods

Studying Trends of AutoRegulation in Severe Head Injury in Paediatrics (STARSHIP) (clinicalTrials.gov identifier-NCT0688462), was a prospective, multicentre, observational, research database study conducted across 10 identified UK Paediatric Intensive Care Units from 01.07.2018 till 31.04.2024. The main objective was to validate and identify optimal thresholds of PRx associated with outcome (as assessed with Glasgow outcome scale extended for Pediatrics at 12 months) in children (<16 years) requiring invasive arterial blood pressure and intracranial pressure monitoring for TBI and establish a comprehensive research database. Apart from high-resolution data, clinical and outcome data up to 12 months post-ictus were collected. Univariable and multivariable analyses including propensity score matching, were employed to determine the effect of PRx on outcome whilst considering covariates, centre-specific differences and other multimodal metrics.

Findings

Out of 153 recruited, 135 children (median age 96 months) with consent and adequate data were included. Overall median PRx of the cohort was -0.09 (IQR -0.19 to 0.08). Both ICP and PRx were elevated in non-survivors and children with unfavourable outcome. PRx retained a significant effect on outcome after adjusting for various clinical and monitoring variables. The critical PRx threshold identified were 0.5 for mortality and 0.0 for favourable outcome.

Interpretation

With STARSHIP, we validate the outcome association of CA derangements as assessed by PRx in pTBI in the first prospective observational multicentre study. This provides additional evidence for the potential use of PRx for individualizing prognosis and treatment and pave way for further research in pTBI with the created database.

Funding

This study was funded by Action Medical Research for Children's Charity and Addenbrookes Charitable Trust, UK (Grant number-GN2609). Cambridge University Hospitals is the study sponsor (Reference: A094693, contact person: Michelle Ellerbeck-michelle.ellerbeck@nhs.net).

Sex Differences in Neurological Outcome at 6 and 12 Months Following Severe Traumatic Brain Injury. An Observational Analysis of the OXY-TC Trial

The effect of sex in outcomes after severe traumatic brain injury (TBI) remains uncertain. We explored whether outcomes differed between women and men after standardized care management during the first 5 days in the intensive care unit (ICU). This study was an observational analysis of the OXY-TC multicenter randomized clinical trial between June 15, 2016 and April 17, 2021. Recruited patients had a pre-hospital Glasgow Coma Scale (GCS) score of 3-8, mechanical ventilation, and intracranial pressure (ICP) with or without brain tissue oxygen pressure (PbtO2) monitoring. Objectives were to maintain ICP at 20 mmHg or below and PbtO2 above 20 mmHg at all times. The primary end-point was the proportion of women and men with poor outcomes at 6 months, corresponding to an extended Glasgow Outcome Scale (GOSE) score of 1-4 (death to upper severe disability). Of 318 randomized patients, 200 men and 71 women were analyzed. They were comparable in age, comorbidities, and initial injury severity scores. However, women had larger doses of ICP as the proportion of monitoring time of ICP above 20 mmHg 8% (3-18; median, interquartile range) versus 3% (1-10), respectively (p = 0.002). They required more often at least one tier-3 treatment, i.e., barbiturate coma and therapeutic hypothermia, for refractory intracranial hypertension during the first 5 days in the ICU: 33/68 (48%) versus 60/193 (31%), respectively (p = 0.012). At 6 months, the proportion of women with GOSE 1-4 was significantly higher than men: 48/71 (68%) versus 94/200 (47%), respectively (odds ratio 2.35 [1.33-4.16]; p = 0.003]. Similar differences were found using Disability Rating Scale and Functional Independence Measure at 6 and 12 months, and GOSE at 12 months. Sex differences in neurological outcomes persisted after adjustment for other determinants of outcome such as age, initial GCS score, and dose of ICP during the 5-day monitoring. In conclusion, women sustained more severe ICP and required more active treatment, both of which would explain a worse outcome after severe TBI. Prospective research is required to confirm these findings and identify possible mechanisms. Trial registration: ClinicalTrials.gov Identifier NCT02754063 (April 28, 2016).

Relationship between growth differentiation factor 15 and functional prognosis and severity in traumatic brain injury

Circulating growth differentiation factor 15 (GDF-15) increases in response to inflammation and tissue damage. Its association with functional prognosis in cerebral infarction and subarachnoid hemorrhage is established; however, its role in traumatic brain injury (TBI) and its relationship with Sequential Organ Failure Assessment (SOFA) score, an indicator of systemic organ damage in TBI, remains unclear. This study aimed to explore the correlation between GDF-15 and functional outcomes at discharge in patients with TBI and stroke, including its association with SOFA scores in TBI. Patients with cerebral infarction, subarachnoid hemorrhage, and TBI transported within 24 h from July 2020 to August 2022 were included. Multivariable logistic regression analyzed the relationship between GDF-15 levels at admission and functional outcomes at discharge, with age and sex as covariates. Additionally, correlations between GDF-15 levels and SOFA scores were assessed. Multivariable logistic regression showed a relationship between GDF-15 levels at admission and functional outcomes at discharge in cerebral infarction and subarachnoid hemorrhage but not in TBI. In TBI cases, GDF-15 correlated with SOFA scores, indicating its potential as a TBI severity marker. Although functional prognosis at discharge was evaluated, long-term outcomes were not clear, and this will be addressed in future research.

Sex Differences in Moderate-to-Severe Traumatic Brain Injury Randomized Controlled Trials

BACKGROUND

Understanding sex differences among persons with moderate-to-severe traumatic brain injury (TBI) is critical to addressing the unique needs of both males and females from acute care through to rehabilitation. Epidemiological studies suggest that 7 of every 10 persons with moderate-to-severe TBI are male, with females representing about 30%-33%.

OBJECTIVE

To examine the proportion of female and male individuals included in randomized controlled trials (RCTs) of interventions for moderate-to-severe TBI.

METHODS

A systematic review was conducted in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines up to and including December 2022 using MEDLINE, PubMed, Scopus, CINAHL, EMBASE and PsycINFO databases. Studies were included if they met the following criteria: (1) human participants with a mean age ≥18 years, (2) ≥50% of the sample had moderate-to-severe TBI and (3) the study design was a RCT. Data extracted included author, year, country, sample size, number of female/male participants and time post-injury.

RESULTS

595 RCTs met the criteria for inclusion, published between 1978 and 2022, totaling 86,662 participants. The average proportion of female participants was 23.14%, and the percentage increased a small but significant amount over time. There was a significantly lower percentage of female participants in RCTs initiated in the acute phase (≤ 1 month) when compared with RCTs conducted in the chronic phase (≥ 6 months) post-injury (p < 0.001).

CONCLUSIONS

Female participants are underrepresented in RCTs of moderate-to-severe TBI. Addressing this underrepresentation is critical to establish effective treatments for all persons with TBI.

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.

Increase in Functional Tic Presentations in Sexual Orientation and Gender Identity Minority Youth During Coronavirus Disease 2019

BACKGROUND

Functional tic disorders are among the least common functional movement disorders, but their prevalence rose during the coronavirus disease 2019 (COVID-19) pandemic. Although female adolescents develop functional neurological disorders at higher rates than males, investigations into sexual orientation and gender identity (SOGI) status of these patients are limited.

METHODS

We completed a retrospective, cross-sectional time series examining the incidence of new-onset functional tic disorders in youth presenting to the Massachusetts General Hospital Movement Disorder clinics before and during the COVID-19 pandemic. Data were collected by searching for relevant International Classification of Diseases (ICD)-10 diagnostic codes in youth aged nine to 26 years using a hospital-wide data repository. Individual cases were reviewed for inclusion based on clinical criteria and expert consensus.

RESULTS

The prevalence of functional tic presentations in youth rose 8.6-fold from pre- to postpandemic levels (Fisher exact test P < 0.001), whereas the prevalence of developmental tic presentations pre- and postpandemic remained stable (114 vs 112). SOGI minority youth comprised 37% of those with functional tics (total n = 19). Ninety five percent of patients with functional tics identified as female, with 10% of these identifying as transgender.

CONCLUSIONS

Our data confirm previously demonstrated dramatic rises in functional tic presentations during the COVID-19 pandemic and, more notably, reveal a strong association with SOGI minority status. We highlight the potential link between functional tic disorders and SOGI minority status. Providing a safe and supportive clinical environment and addressing stress linked to SOGI minority status may help to improve patient prognosis.

Impact of menopause-associated frailty on traumatic brain injury

Navigating menopause involves traversing a complex terrain of hormonal changes that extend far beyond reproductive consequences. Menopausal transition is characterized by a decrease in estradiol-17β (E2), and the impact of menopause resonates not only in the reproductive system but also through the central nervous system, musculoskeletal, and gastrointestinal domains. As women undergo menopausal transition, they become more susceptible to frailty, amplifying the risk and severity of injuries, including traumatic brain injury (TBI). Menopause triggers a cascade of changes leading to a decline in muscle mass, accompanied by diminished tone and excitability, thereby restricting the availability of irisin, a crucial hormone derived from muscles. Concurrently, bone mass undergoes reduction, culminating in the onset of osteoporosis and altering the dynamics of osteocalcin, a hormone originating from bones. The diminishing levels of E2 during menopause extend their influence on the gut microbiota, resulting in a reduction in the availability of tyrosine, tryptophan, and serotonin metabolites, affecting neurotransmitter synthesis and function. Understanding the interplay between menopause, frailty, E2 decline, and the intricate metabolisms of bone, gut, and muscle is imperative when unraveling the nuances of TBI after menopause. The current review underscores the significance of accounting for menopause-associated frailty in the incidence and consequences of TBI. The review also explores potential mechanisms to enhance gut, bone, and muscle health in menopausal women, aiming to mitigate frailty and improve TBI outcomes.

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.

Repurposing of pexidartinib for microglia depletion and renewal

Pexidartinib (PLX3397) is a small molecule receptor tyrosine kinase inhibitor of colony stimulating factor 1 receptor (CSF1R) with moderate selectivity over other members of the platelet derived growth factor receptor family. It is approved for treatment of tenosynovial giant cell tumors (TGCT). CSF1R is highly expressed by microglia, which are macrophages of the central nervous system (CNS) that defend the CNS against injury and pathogens and contribute to synapse development and plasticity. Challenged by pathogens, apoptotic cells, debris, or inflammatory molecules they adopt a responsive state to propagate the inflammation and eventually return to a homeostatic state. The phenotypic switch may fail, and disease-associated microglia contribute to the pathophysiology in neurodegenerative or neuropsychiatric diseases or long-lasting detrimental brain inflammation after brain, spinal cord or nerve injury or ischemia/hemorrhage. Microglia also contribute to the growth permissive tumor microenvironment of glioblastoma (GBM). In rodents, continuous treatment for 1-2 weeks via pexidartinib food pellets leads to a depletion of microglia and subsequent repopulation from the remaining fraction, which is aided by peripheral monocytes that search empty niches for engraftment. The putative therapeutic benefit of such microglia depletion or forced renewal has been assessed in almost any rodent model of CNS disease or injury or GBM with heterogeneous outcomes, but a tendency of partial beneficial effects. So far, microglia monitoring e.g. via positron emission imaging is not standard of care for patients receiving Pexidartinib (e.g. for TGCT), so that the depletion and repopulation efficiency in humans is still largely unknown. Considering the virtuous functions of microglia, continuous depletion is likely no therapeutic option but short-lasting transient partial depletion to stimulate microglia renewal or replace microglia in genetic disease in combination with e.g. stem cell transplantation or as part of a multimodal concept in treatment of glioblastoma appears feasible. The present review provides an overview of the preclinical evidence pro and contra microglia depletion as a therapeutic approach.

A thematic analysis of patients' and their informal caregivers' gendered experiences in traumatic brain injury

PURPOSE

Research shows that patients' perceptions of themselves and others, in addition to their understanding of the concept of gender, changes after traumatic brain injury (TBI). Little is known about gendered experiences in TBI and care delivery. This study aims to explore perceptions of gender through life experiences and interactions between adult patients with TBI and their informal caregivers.

MATERIALS AND METHODS

Seven patients with mild and moderate-severe TBI and eight informal caregivers were interviewed. Transcripts were coded and analysed according to Braun and Clarke's thematic analysis. The Consolidated Criteria for Reporting Qualitative Research guidelines were followed in reporting results.

RESULTS

The participants described a transformation of their understanding and experiences of gender following the TBI event. Three themes were identified: (1) Gender designations of "man" and "woman";( 2) Post-injury performativity of gender; and (3) Gender in giving and receiving care.

CONCLUSIONS

The findings emphasize the importance of raising awareness among researchers and practitioners on gender as a transformative process for patients with TBI and informal caregivers after the injury. The diversity of patient-caregiver experiences and critical needs based on gender call for intervention approaches that mitigate gender disparities in giving and receiving care. Implications for RehabilitationHistorically, rehabilitation of persons with traumatic brain injury has targeted physical and cognitive impairments, with little attention to their gendered demands in the lived environment.Gender prevails in the lived experiences of persons with traumatic brain injury, and their informal caregivers, and in giving and receiving quality care.A major challenge for clinicians is identifying harmful gendered roles, norms, and relations and the affective/behavioral problems they produce to alleviate enduring distress and reduce disability.Rehabilitation interventions focusing on flexible and adaptive responses to gendered demands in the lived environment of persons with traumatic brain injury are timely.

Timing matters: Sex differences in inflammatory and behavioral outcomes following repetitive blast mild traumatic brain injury

BACKGROUND

Repetitive blast-related mild traumatic brain injury (mTBI) caused by exposure to high explosives is increasingly common among warfighters as well as civilians. While women have been serving in military positions with increased risk of blast exposure since 2016, there are few published reports examining sex as a biological variable in models of blast mTBI, greatly limiting diagnosis and treatment capabilities. As such, here we examined outcomes of repetitive blast trauma in female and male mice in relation to potential behavioral, inflammatory, microbiome, and vascular dysfunction at multiple timepoints.

METHODS

In this study we utilized a well-established blast overpressure model to induce repetitive (3x) blast-mTBI in both female and male mice. Acutely following repetitive exposure, we measured serum and brain cytokine levels, blood-brain barrier (BBB) disruption, fecal microbial abundance, and locomotion and anxiety-like behavior in the open field assay. At the one-month timepoint, in female and male mice we assessed behavioral correlates of mTBI and PTSD-related symptoms commonly reported by Veterans with a history of blast-mTBI using the elevated zero maze, acoustic startle, and conditioned odorant aversion paradigms.

RESULTS

Repetitive blast exposure resulted in both similar (e.g., increased IL-6), and disparate (e.g., IL-10 increase only in females) patterns of acute serum and brain cytokine as well as gut microbiome changes in female and male mice. Acute BBB disruption following repetitive blast exposure was apparent in both sexes. While female and male blast mice both exhibited acute locomotor and anxiety-like deficits in the open field assay, only male mice exhibited adverse behavioral outcomes that lasted at least one-month.

DISCUSSION

Representing a novel survey of potential sex differences following repetitive blast trauma, our results demonstrate unique similar yet divergent patterns of blast-induced dysfunction in female vs. male mice and highlight novel targets for future diagnosis and therapeutic development.

Pregnancy, Fetal, and Neonatal Outcomes Among Women With Traumatic Brain Injury

OBJECTIVE

There have been no systematic studies of pregnancy outcomes among women with traumatic brain injury (TBI), potentially limiting informed clinical care for women with such injuries. The purpose of this exploratory study was to evaluate pregnancy and fetal/neonatal outcomes among women with a TBI diagnosis recorded during their delivery hospitalization compared with women without TBI.

SETTING

In this cross-sectional study, we identified women with delivery hospitalizations using 2004-2014 data from the Nationwide Inpatient Sample of the Health Care and Cost Utilization Project.

PARTICIPANTS

We identified deliveries to women with a TBI diagnosis on hospital discharge records, which included all diagnoses recorded during the delivery, and compared them with deliveries of women without a TBI diagnosis.

MAIN MEASURES

Pregnancy outcomes included gestational diabetes; preeclampsia/eclampsia; placental abruption; cesarean delivery; and others. Fetal/neonatal outcomes included preterm birth; stillbirth; and small or large gestational age.

DESIGN

We modeled risk for each outcome among deliveries to women with TBI compared with women without TBI, using multivariate Poisson regression. Models included sociodemographic and hospital characteristics; secondary models added clinical characteristics (eg, psychiatric disorders) that may be influenced by TBI.

RESULTS

We identified 3 597 deliveries to women with a TBI diagnosis and 9 106 312 deliveries to women without TBI. Women with TBI were at an increased risk for placental abruption (relative risk [RR] = 2.73; 95% CI, 2.26-3.30) and associated sequelae (ie, antepartum hemorrhage, cesarean delivery). Women with TBI were at an increased risk for stillbirth (RR = 2.55; 95% CI, 1.97-3.29) and having a baby large for gestational age (RR = 1.30; 95% CI, 1.09-1.56). Findings persisted after controlling for clinical characteristics.

CONCLUSIONS

Risk for adverse pregnancy outcomes, including placental abruption and stillbirth, were increased among women with TBI. Future research is needed to examine the association between TBI and pregnancy outcomes using longitudinal and prospective data and to investigate potential mechanisms that may heighten risk for adverse outcomes.

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.

The role of social determinants of health in the receipt of school services after\\ traumatic brain injury: A focus review on underserved pediatric populations

BACKGROUND

Return to school is key for community re-integration after a traumatic brain injury (TBI). School support facilitates and ensure a successful transition back to school. However, access to school services is not uniform among U.S. children.

OBJECTIVE

To describe school services for children with TBI from minoritized backgrounds and highlight population-specific risk factors and facilitators for accessing services.

METHODS

Narrative review of the literature including studies on return to school after a mild-complicated, moderate, or severe TBI, among children enrolled in the U.S. school system. We describe receipt of services, enabling and risk factors, and outcomes, for minority children.

RESULTS

There is a gap in knowledge regarding return to school among minoritized children with TBIs. Studies have few participants from racial and ethnic minority backgrounds, or low income or rural communities. Transgender and non-binary youth are not represented in present research efforts. Studies highlight larger barriers to receipt of school services among minority children and additional barriers associated with their minority status.

CONCLUSION

Diversity in the U.S pediatric population is increasing. Minoritized populations are at increased risk for TBI and poor outcomes. Research focused on the needs of these populations is required to optimize school return after TBI hospitalization and overall post-discharge care.

Lipocalin-2 Is a Key Regulator of Neuroinflammation in Secondary Traumatic and Ischemic Brain Injury

Reactive glial cells are hallmarks of brain injury. However, whether these cells contribute to secondary inflammatory pathology and neurological deficits remains poorly understood. Lipocalin-2 (LCN2) has inflammatory and neurotoxic effects in various disease models; however, its pathogenic role in traumatic brain injury remains unknown. The aim of the present study was to investigate the expression of LCN2 and its role in neuroinflammation following brain injury. LCN2 expression was high in the mouse brain after controlled cortical impact (CCI) and photothrombotic stroke (PTS) injury. Brain levels of LCN2 mRNA and protein were also significantly higher in patients with chronic traumatic encephalopathy (CTE) than in normal subjects. RT-PCR and immunofluorescence analyses revealed that astrocytes were the major cellular source of LCN2 in the injured brain. Lcn2 deficiency or intracisternal injection of an LCN2 neutralizing antibody reduced CCI- and PTS-induced brain lesions, behavioral deficits, and neuroinflammation. Mechanistically, in cultured glial cells, recombinant LCN2 protein enhanced scratch injury-induced proinflammatory cytokine gene expression and inhibited Gdnf gene expression, whereas Lcn2 deficiency exerted opposite effects. Together, our results from CTE patients, rodent brain injury models, and cultured glial cells suggest that LCN2 mediates secondary damage response to traumatic and ischemic brain injury by promoting neuroinflammation and suppressing the expression of neurotropic factors.

Repeat subconcussion in the adult rat gives rise to behavioral deficits similar to a single concussion but different depending upon sex

Although concussions are a popular focus of neurotrauma research, subconcussions occur with higher frequency but are less well-studied. A subconcussion is an impact to the head that does not result in immediately diagnosable concussion but can result in later neurological consequences. Repeat subconcussions can produce behavioral impairments and neuropathology that is similar to or worse than those seen following a single concussion. The current study modified a previously established closed head injury model of concussion to create a subconcussion model and examines sex differences in behavioral responses to repeated subconcussion in the adult rat. Rats received a single concussion, single or repeat subconcussions, or no impact and behavior was monitored from 2 h through 31 days post-injury. A single concussion or repeat subconcussion resulted in deficits in locomotion, righting reflexes, and recognition memory. The degree of deficit induced by repeat subconcussions were either similar (righting reflexes) or greater/more persistent (locomotor deficits and recognition memory) than that of a concussion. Single subconcussion resulted in acute deficits that were mild and limited to righting reflexes and locomotion. Sex differences were observed in responses to repeat subconcussion: females showed greater deficits in righting reflexes, locomotion, and vestibular function, while males showed greater alterations in anxiety and depressive-like behavior. This study established a model of subconcussive impact where a single subconcussive impact resulted in minimal behavioral deficits but repeat subconcussions resulted in deficits similar to or worse than a single concussion. Our data also suggest sex differences in behavioral responses to both concussive and subconcussive impacts.

Integration of multiple prognostic predictors in a porcine spinal cord injury model: A further step closer to reality

Introduction

Spinal cord injury (SCI) is a devastating neurological disorder with an enormous impact on individual's life and society. A reliable and reproducible animal model of SCI is crucial to have a deeper understanding of SCI. We have developed a large-animal model of spinal cord compression injury (SCI) with integration of multiple prognostic factors that would have applications in humans.

Methods

Fourteen human-like sized pigs underwent compression at T8 by implantation of an inflatable balloon catheter. In addition to basic neurophysiological recording of somatosensory and motor evoked potentials, we introduced spine-to-spine evoked spinal cord potentials (SP-EPs) by direct stimulation and measured them just above and below the affected segment. A novel intraspinal pressure monitoring technique was utilized to measure the actual pressure on the cord. The gait and spinal MRI findings were assessed in each animal postoperatively to quantify the severity of injury.

Results

We found a strong negative correlation between the intensity of pressure applied to the spinal cord and the functional outcome (P < 0.0001). SP-EPs showed high sensitivity for real time monitoring of intraoperative cord damage. On MRI, the ratio of the high-intensity area to the cross-sectional of the cord was a good predictor of recovery (P < 0.0001).

Conclusion

Our balloon compression SCI model is reliable, predictable, and easy to implement. By integrating SP-EPs, cord pressure, and findings on MRI, we can build a real-time warning and prediction system for early detection of impending or iatrogenic SCI and improve outcomes.

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.

Moderate and severe TBI in children and adolescents: The effects of age, sex, and injury severity on patient outcome 6 months after injury

The interaction of age, sex, and outcomes of children with head injury remains incompletely understood and these factors need rigorous evaluation in prognostic models for pediatric head injury. We leveraged our large institutional pediatric TBI population to evaluate age and sex along with a series of predictive factors used in the acute care of injury to describe the response and outcome of children and adolescents with moderate to severe injury. We hypothesized that younger age at injury and male sex would be associated with adverse outcomes and that a novel GCS-based scale incorporating pupillary response (GCS-P) would have superior performance in predicting 6-month outcome. GCS and GCS-P along with established CT scan variables associated with neurologic outcomes were retrospectively reviewed in children (age birth to 18 years) with moderate or severe head injury. GOS-E was prospectively collected 6 months after injury; 570 patients were enrolled in the study, 520 with TBI and 50 with abusive head trauma, each analyzed separately. In the TBI cohort, the median age of patients was 8 years and 42.7% had a severe head injury. Multiple predictors of outcome were identified in univariate analysis; however, based on a multivariate analysis, the GCS was identified as most reliable, outperforming GCS-P, pupil score, and other clinical and CT scan predictors. After stratifying patients for severity of injury by GCS, no age- or sex-related effects were observed in our patient population, except for a trend toward worse outcomes in the neonatal group. Patients with abusive head trauma were more likely to have severe injury on presentation, increased mortality rate, and unfavorable outcome. Additionally, there was clear evidence that secondary injuries, including hypoxia, hypotension, and hypothermia were significantly associated with lower GCS and higher mortality in both AHT and TBI populations. Our findings support the use of GCS to guide clinical decision-making and prognostication in addition to emphasizing the need to stratify head injuries for severity when undertaking outcome studies. Finally, secondary injuries are a clear predictor of poor outcome and how we record and manage these events need to be considered moving forward.

Sex specific effects of buprenorphine on behavior, astrocytic opioid receptor expression and neuroinflammation after pediatric traumatic brain injury in mice

Children who suffered traumatic brain injury (TBI) often experience acute and chronic pain, which is linked to a poor quality of life. Buprenorphine (BPN) is commonly used to treat moderate to severe persistent pain in children, however, the efficacy and safety profile of BPN in the pediatric population is still inconclusive. This study investigated the sex-specific effects of BPN on body weight, motor coordination and strength, expression of opioid receptors in the white matter astrocytes, and neuroinflammation in a mouse impact acceleration model of pediatric TBI. Male and female littermates were randomized on postnatal day 20-21(P20-21) into Sham, TBI + saline and TBI + BPN groups. Mice in the TBI + saline and TBI + BPN groups underwent TBI, while the Sham group underwent anesthesia without injury. BPN (0.075 mg/kg) was administered to the TBI + BPN mice at 30 min after injury, and then every 6-12 h for 2 days. Mice in the TBI + saline group received the same amount of saline injections. The impact of BPN on body weight, motor function, opioid receptor expression, and neuroinflammation was evaluated at 1-day (d), 3-d and 7-d post-injury. We found that 1) TBI induced significant weight loss in both males and females. BPN treatment improved weight loss at 3-d post-injury in females. 2) TBI significantly impaired motor coordination and strength. BPN improved motor coordination and strength in both males and females at 1-d and 3-d post-injury. 3) TBI significantly decreased exploration activity at 1-d post-injury in males, and at 7-d post-injury in females, while BPN improved the exploration activity in females. 4) TBI significantly increased mRNA expression of mu-opioid receptors (MOR) at 7-d post-injury in males, but decreased mRNA expression of MOR at 1-d post-injury in females. BPN normalized MOR mRNA expression at 1-d post-injury in females. 5) MOR expression in astrocytes at corpus callosum significantly increased at 7-d post-injury in male TBI group, but significantly decreased at 1-d post-injury in female TBI group. BPN normalized MOR expression in both males and females. 6) TBI significantly increased the mRNA expression of TNF-α, IL-1β, IL-6 and iNOS. BPN decreased mRNA expression of iNOS, and increased mRNA expression of TGF-β1. In conclusion, this study elucidates the sex specific effects of BPN during the acute phase after pediatric TBI, which provides the rationale to assess potential effects of BPN on chronic pathological progressions after pediatric TBI in both males and females.

Traumatic brain injury in women across lifespan

Traumatic brain injury (TBI) is a leading cause of death and disability and a global public health challenge. Every year more than 50 million people suffer a TBI, and it is estimated that 50% of the global population will experience at least one TBI in their lifetime. TBI affects both men and women of all ages, however there is a male bias in TBI research as women have frequently been left out of the literature despite irrefutable evidence of male and female dimorphism in several posttraumatic measures. Women uniquely experience distinct life stages marked by levels of endogenous circulating sex hormones, as well as by physiological changes that are nonexistent in men. In addition to generalized sex-specific differences, a woman's susceptibility, neurological outcomes, and treatment success may vary considerably depending upon when in her lifespan she incurred a traumatic insult. How women impacted by TBI might differ from other women as a factor of age and physiology is not well understood. Furthermore, there is a gap in the knowledge of what happens when TBI occurs in the presence of certain sex-specific and sex-nonspecific variables, such as during pregnancy, with oral contraceptive use, in athletics, in cases of addiction and nicotine consumption, during perimenopause, postmenopause, in frailty, among others. Parsing out how hormone-dependent and hormone-independent lifespan variables may influence physiological, neurodegenerative, and functional outcomes will greatly contribute to future investigative studies and direct therapeutic strategies. The goal of this review is to aggregate the knowledge of prevalence, prognosis, comorbid risk, and response of women incurring TBI at differing phases of lifespan. We strive to illuminate commonalities and disparities among female populations, and to pose important questions to highlight gaps in the field in order to further the endeavor of targeted treatment interventions in a patient-specific manner.

Sex Differences in Behavioral Symptoms and the Levels of Circulating GFAP, Tau, and NfL in Patients With Traumatic Brain Injury

Traumatic brain injury (TBI) affects millions of Americans each year and has been shown to disproportionately impact those subject to greater disparities in health. Female sex is one factor that has been associated with disparities in health outcomes, including in TBI, but sex differences in biomarker levels and behavioral outcomes after TBI are underexplored. This study included participants with both blunt and blast TBI with majority rating their TBI as mild. Time since injury was 5.4 (2.0, 15.5) years for females and 6.8 (2.4, 11.3) years for males. The aim of this cross sectional study is to investigate the relationship between postconcussive, depression, and post-traumatic stress disorder (PTSD) symptoms, as well as health related quality of life (HRQOL), and the levels of glial fibrillary acidic protein (GFAP), total tau (t-tau), neurofilament light chain (NfL), and ubiquitin C-terminal hydrolase-L1 (UCH-L1). Behavioral outcomes were evaluated with the Neurobehavioral Symptom Inventory (NSI), Patient Health Questionnaire-9 (PHQ-9), PTSD Checklist- Civilian Version (PCL-C), short form (SF)-36, and plasma levels of total tau, GFAP, NfL, and UCHL-1 measured with the Simoa-HDX. We observed that females had significantly higher levels of GFAP and tau (ps < 0.05), and higher PHQ-9 scores, NSI total scores, NSI- vestibular, NSI-somatosensory, NSI-affective sub-scale scores (ps < 0.05)), than males. In addition, females had lower scores in HRQOL outcomes of role limitations due to emotional problems, vitality, emotional well-being, social functioning, and pain compared to males (ps < 0.05). Correlation analysis showed positive associations between levels of tau and the NSI-total and NSI-cognitive sub-scale scores (ps < 0.05) in females. No significant associations were found for NfL or GFAP with NSI scores. For female participants, negative correlations were observed between tau and NfL concentrations and the SF-36 physical function subscale (ps < 0.05), as well as tau and the social function subscale (p < 0.001), while GFAP levels positively correlated with role limitations due to emotional problems (p = 0.004). No significant associations were observed in males. Our findings suggest that sex differences exist in TBI-related behavioral outcomes, as well as levels of biomarkers associated with brain injury, and that the relationship between biomarker levels and behavioral outcomes is more evident in females than males. Future studies are warranted to corroborate these results, and to determine the implications for prognosis and treatment. The identification of candidate TBI biomarkers may lead to development of individualized treatment guidelines.

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

Background: Although traumatic brain injury (TBI) is a leading cause of death and disability in male and female patients worldwide, little is known about the effect of sex and gender on TBI outcomes. Objectives: This systematic review summarizes the evidence on the effect of sex and gender on core TBI outcomes. Methods: All English-language studies from six literature databases that addressed core outcomes in adults with TBI and included sex or gender, TBI severity, and age in their analyses were considered eligible. Two reviewers extracted data, and two reviewers assessed study quality using tools recommended by the National Institutes of Health. The results were sorted according to time post-injury, injury severity, gender equity ranking of the study's country of origin, and outcomes studied. The results from the included studies were grouped based on the approach taken in reporting their respective findings. Results and Limitations: Of 172 articles assessed, 58 studies were selected, comprising 1, 265, 955 participants with TBI (67% male across all studies) of all injury severities. All studies were conducted in countries with a very high or high human development index, while the Gender Inequality Index (GII) varied. While the heterogeneity across studies limited any meaningful conclusions with respect to the role of sex and gender, we did observe that as gender equality ranking improved, differences between male and female participants in outcomes would diminish. Inclusion of social equity parameters in the studies was limited. Conclusions and Implications: The non-uniform findings observed bring forth the need to develop and use a comprehensive and consistent methodology in the study of sex and gender post-TBI, incorporating social equity parameters to uncover the potential social underpinnings of gender effects on health and functional outcomes. Systematic Review Registration: CRD42018098697.

The features of the typical traumatic brain injury patient in the ICU are changing: what will this mean for the intensivist?

PURPOSE OF REVIEW

To describe the key features and epidemiology of traumatic brain injury (TBI) and how they may be changing, with an emphasis on how this may affect care in the intensive care unit.

RECENT FINDINGS

TBI has been traditionally perceived as occurring mainly in a younger, predominantly male population injured in high velocity motor vehicle crashes or assaults. However, there are an increasing number of patients over 65 years who have sustained a TBI secondary to low velocity falls. Considering the effects of frailty, comorbidities and extracranial injuries is important when making management decisions. Mild TBI comprises a third of those admitted and as a significant proportion may have poor outcomes secondary to their TBI they should be assessed to ensure appropriate follow-up. Multimodal monitoring may offer a way in the future to offer more personalised management to this very complex and heterogeneous patient group.

SUMMARY

This review highlights the urgent need to develop more age-inclusive TBI consensus management guidelines aimed at improving short- and long-term outcomes for the large and growing TBI population. Being elderly does not necessarily portend a poor outcome, and more research is needed to better triage, guide management and prognosticate on these patients.

Spatial Distribution of Neuropathology and Neuroinflammation Elucidate the Biomechanics of Fluid Percussion Injury

Diffuse brain injury is better described as multi-focal, where pathology can be found adjacent to seemingly uninjured neural tissue. In experimental diffuse brain injury, pathology and pathophysiology have been reported far more lateral than predicted by the impact site. We hypothesized that local thickening of the rodent skull at the temporal ridges serves to focus the intracranial mechanical forces experienced during brain injury and generate predictable pathology. We demonstrated local thickening of the skull at the temporal ridges using contour analysis on magnetic resonance imaging. After diffuse brain injury induced by midline fluid percussion injury (mFPI), pathological foci along the anterior-posterior length of cortex under the temporal ridges were evident acutely (1, 2, and 7 days) and chronically (28 days) post-injury by deposition of argyophilic reaction product. Area CA3 of the hippocampus and lateral nuclei of the thalamus showed pathological change, suggesting that mechanical forces to or from the temporal ridges shear subcortical regions. A proposed model of mFPI biomechanics suggests that injury force vectors reflect off the skull base and radiate toward the temporal ridge, thereby injuring ventral thalamus, dorsolateral hippocampus, and sensorimotor cortex. Surgically thinning the temporal ridge before injury reduced injury-induced inflammation in the sensorimotor cortex. These data build evidence for temporal ridges of the rodent skull to contribute to the observed pathology, whether by focusing extracranial forces to enter the cranium or intracranial forces to escape the cranium. Pre-clinical investigations can take advantage of the predicted pathology to explore injury mechanisms and treatment efficacy.