Association of Traumatic Brain Injury With the Risk of Developing Chronic Cardiovascular, Endocrine, Neurological, and Psychiatric Disorders

A Transdiagnostic, Hierarchical Taxonomy of Psychopathology Following Traumatic Brain Injury (HiTOP-TBI)

Psychopathology, including depression, anxiety, and post-traumatic stress, is a significant yet inadequately addressed feature of moderate-severe traumatic brain injury (TBI). Progress in understanding and treating post-TBI psychopathology may be hindered by limitations associated with conventional diagnostic approaches, specifically the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD). The Hierarchical Taxonomy of Psychopathology (HiTOP) offers a promising, transdiagnostic alternative to psychiatric classification that may more effectively capture the experiences of individuals with TBI. However, HiTOP lacks validation in the TBI population. To address this gap, we administered a comprehensive questionnaire battery, including 56 scales assessing homogeneous symptom components and maladaptive traits within HiTOP, to 410 individuals with moderate-severe TBI. We evaluated the reliability and unidimensionality of each scale and revised those with psychometric problems. Using a top-down, exploratory latent variable approach (bass-ackwards modeling), we subsequently constructed a hierarchical model of psychopathological dimensions tailored to TBI. The results showed that, relative to norms, participants with moderate-severe TBI experienced greater problems in the established HiTOP internalizing and detachment spectra, but fewer problems with thought disorder and antagonism. Fourteen of the 56 scales demonstrated psychometric problems, which often appeared reflective of the TBI experience and associated disability. The Hierarchical Taxonomy of Psychopathology Following Traumatic Brain Injury (HiTOP-TBI) model encompassed broad internalizing and externalizing spectra, splitting into seven narrower dimensions: Detachment, Dysregulated Negative Emotionality, Somatic Symptoms, Compensatory and Phobic Reactions, Self-Harm and Psychoticism, Rigid Constraint, and Harmful Substance Use. This study presents the most comprehensive empirical classification of psychopathology after TBI to date. It introduces a novel, TBI-specific transdiagnostic questionnaire battery and model, which addresses the limitations of conventional DSM and ICD diagnoses. The empirical structure of psychopathology after TBI largely aligned with the established HiTOP model (e.g., a detachment spectrum). However, these constructs need to be interpreted in relation to the unique experiences associated with TBI (e.g., considering the injury's impact on the person's social functioning). By overcoming the limitations of conventional diagnostic approaches, the HiTOP-TBI model has the potential to accelerate our understanding of the causes, correlates, consequences, and treatment of psychopathology after TBI.

Barriers and enablers to physical activity for individuals living with traumatic brain injury: a mixed methods systematic review

BACKGROUND

Despite well-documented benefits of physical activity (PA), people with brain injury face numerous PA barriers. This mixed methods systematic review aimed to summarize barriers and enablers that individuals with traumatic brain injury (TBI) experience when participating in PA.

METHODS

Primary studies investigating barriers and/or enablers to PA in adults living with TBI were included. Literature search in MEDLINE, EmCare, Embase, PsychINFO, PEDro, and OTSeeker was initially conducted in December 2021 and January 2022, and updated in June 2022. Methodological quality of the included studies was assessed using Joanna Briggs Institute critical appraisal tools. A customized data extraction form was utilized. Descriptive synthesis was used to summarize the findings.

RESULTS

Twelve studies of various methodological qualities were identified. Barriers to PA included personal issues, changing health status, external factors, lack of support, and lack of knowledge. Identified enablers included personal drivers, social support, professional support, accessibility, and education.

CONCLUSIONS

The shared similarities between barriers and enablers across several themes suggest that multiple barriers may be amenable to change. Given the diverse barriers to PA, health professionals should use person-centered, holistic approach with ongoing review and monitoring, when engaging with individuals with TBI.

Catecholamine concentration as a predictor of mortality in emergency surgical patients

BACKGROUND

Trauma and emergency surgery are major causes of morbidity and mortality. The objective of this study was to determine whether serum levels of epinephrine and norepinephrine are associated with aging and mortality.

METHODS

This was a prospective observational cohort study conducted in a surgical critical care unit. We included 90 patients who were admitted for postoperative care, because of major trauma, or both. We collected demographic and clinical variables, as well as serum levels of epinephrine and norepinephrine.

RESULTS

For patients in the > 60-year age group, the use of vasoactive drugs was found to be associated with an undetectable epinephrine level (OR [95% CI] = 6.36 [1.12, 36.08]), p = 0.05). For the patients with undetectable epinephrine levels, the in-hospital mortality was higher among those with a norepinephrine level ≥ 2006.5 pg/mL (OR [95% CI] = 4.00 [1.27, 12.58]), p = 0.03).

CONCLUSIONS

There is an association between age and mortality. Undetectable serum epinephrine, which is more common in older patients, could contribute to poor outcomes. The use of epinephrine might improve the clinical prognosis in older surgical patients with shock.

Applying Dynamical Systems Theory to Improve Personalized Medicine Following Mild Traumatic Brain Injury

A sizable proportion of patients with mild traumatic brain injury (mTBI) have persistent symptoms and functional impairments months to years following injury. This phenomenon is continually observed despite an explosion of research and interest in improving mTBI clinical outcomes over the last two decades. All pharmacological clinical trials to date have failed to demonstrate improved outcomes for mTBI. One possible explanation for these continued failures is an overly myopic approach to treating mTBI (i.e., testing the effect of a single drug with a specific mechanism on a group of people with highly heterogenous injuries). Clinical presentation and prognosis of mTBI vary considerably between patients, and yet we continue to assess group-level effects of a homogenized treatment. We need to utilize an equally complex treatment approach to match the extraordinary complexity of the human brain. Dynamical systems theory has been used to describe systems composed of multiple subsystems who function somewhat independently but are ultimately interconnected. This theory was popularized in the motor control literature as an overarching framework for how the mind and body connect to interact and move through the environment. However, the human body can be viewed as a dynamical system composed of multiple subsystems (i.e., organ systems) who have isolated functions, which are also codependent on the health and performance of other interconnected organ systems. In this perspective piece, we will use the example of mTBI in the obese patient to demonstrate how broadening our approach to treatment of the individual (and not necessarily the injury) may ultimately yield improved outcomes. Furthermore, we will explore clinical and pre-clinical evidence demonstrating multiple system interactions in the context of obesity and TBI and discuss how expanding our understanding of the mechanistic interplay between multiple organ systems may ultimately provide a more personalized treatment approach for this mTBI patient subpopulation.

Calcium and Non-Penetrating Traumatic Brain Injury: A Proposal for the Implementation of an Early Therapeutic Treatment for Initial Head Insults

Finding an effective treatment for traumatic brain injury is challenging for multiple reasons. There are innumerable different causes and resulting levels of damage for both penetrating and non-penetrating traumatic brain injury each of which shows diverse pathophysiological progressions. More concerning is that disease progression can take decades before neurological symptoms become obvious. Currently, the primary treatment for non-penetrating mild traumatic brain injury, also called concussion, is bed rest despite the fact the majority of emergency room visits for traumatic brain injury are due to this mild form. Furthermore, one-third of mild traumatic brain injury cases progress to long-term serious symptoms. This argues for the earliest therapeutic intervention for all mild traumatic brain injury cases which is the focus of this review. Calcium levels are greatly increased in damaged brain regions as a result of the initial impact due to tissue damage as well as disrupted ion channels. The dysregulated calcium level feedback is a diversity of ways to further augment calcium neurotoxicity. This suggests that targeting calcium levels and function would be a strong therapeutic approach. An effective calcium-based traumatic brain injury therapy could best be developed through therapeutic programs organized in professional team sports where mild traumatic brain injury events are common, large numbers of subjects are involved and professional personnel are available to oversee treatment and documentation. This review concludes with a proposal with that focus.

Thyroid hormone T4 mitigates traumatic brain injury in mice by dynamically remodeling cell type specific genes, pathways, and networks in hippocampus and frontal cortex

The complex pathology of mild traumatic brain injury (mTBI) is a main contributor to the difficulties in achieving a successful therapeutic regimen. Thyroxine (T4) administration has been shown to prevent the cognitive impairments induced by mTBI in mice but the mechanism is poorly understood. To understand the underlying mechanism, we carried out a single cell transcriptomic study to investigate the spatiotemporal effects of T4 on individual cell types in the hippocampus and frontal cortex at three post-injury stages in a mouse model of mTBI. We found that T4 treatment altered the proportions and transcriptomes of numerous cell types across tissues and timepoints, particularly oligodendrocytes, astrocytes, and microglia, which are crucial for injury repair. T4 also reversed the expression of mTBI-affected genes such as Ttr, mt-Rnr2, Ggn12, Malat1, Gnaq, and Myo3a, as well as numerous pathways such as cell/energy/iron metabolism, immune response, nervous system, and cytoskeleton-related pathways. Cell-type specific network modeling revealed that T4 mitigated select mTBI-perturbed dynamic shifts in subnetworks related to cell cycle, stress response, and RNA processing in oligodendrocytes. Cross cell-type ligand-receptor networks revealed the roles of App, Hmgb1, Fn1, and Tnf in mTBI, with the latter two ligands having been previously identified as TBI network hubs. mTBI and/or T4 signature genes were enriched for human genome-wide association study (GWAS) candidate genes for cognitive, psychiatric and neurodegenerative disorders related to mTBI. Our systems-level single cell analysis elucidated the temporal and spatial dynamic reprogramming of cell-type specific genes, pathways, and networks, as well as cell-cell communications as the mechanisms through which T4 mitigates cognitive dysfunction induced by mTBI.

Testosterone and neurobehavioral outcomes in special operations forces military with multiple mild traumatic brain injury

BACKGROUND

U.S. Special Operations Forces (SOF) are at increased risk of multiple mild traumatic brain injury (mmTBI). Testosterone was prescribed for several participants in a VA program designed to address sequelae of mmTBI for SOF.

OBJECTIVE

To determine testosterone prevalence in the Palo Alto VA Intensive Evaluation and Treatment Program (IETP) and observe for association between testosterone and neurobehavioral outcomes.

METHODS

A retrospective cohort study included patients in the Palo Alto VA IETP. Sociodemographic data, testosterone blood levels, and neurobehavioral outcomes were collected from medical records.

RESULTS

55 IETP participants were included: six were testosterone users; the rest were classified as non-users. Testosterone use in this population is 11%, higher than reported national averages in the U.S. Of the 6 testosterone users, 2 (33%) had a formal diagnosis of hypogonadism prior to initiation of testosterone. Neurobehavioral outcome scores between testosterone users and non-users failed to show statistically significant differences, except for the PROMIS pain score, which was higher in the testosterone user population.

CONCLUSION

The current study did not find an association between mmTBI, testosterone use, or testosterone level and neurobehavioral outcomes. This study highlights a need to further examine the relationship between hypogonadism, mmTBI, SOF culture around testosterone, and the effects of testosterone use in this population.

Mental and Physical Health Comorbidities in Traumatic Brain Injury: A Non-TBI Controls Comparison

OBJECTIVE

To examine whether aging with a TBI was associated with a greater burden of health-related comorbidities compared with a non-TBI control cohort and examine the associations between comorbidity burden, emotional outcomes, and health-related quality of life (HRQoL) after TBI across ages.

DESIGN

Cross-sectional.

SETTING

Research center or telephone.

PARTICIPANTS

The study included 559 participants (NTBI=291, NControls=268). Participants with TBI were recruited during inpatient rehabilitation and had sustained a moderate-severe TBI 1-33 years previously. Non-TBI controls were a convenience sample recruited through advertisements in the community.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The number of cardiovascular, general physical health, and mental health comorbidities was compared between cohorts and age strata using Poisson regression. The relationships between comorbidities, age, emotional outcomes (Generalized Anxiety Disorder Scale-7, Patient Health Questionnaire-9), and HRQoL (PROMIS Global Health Measure) were examined with linear regression. Distinct subgroups of comorbidities were identified using latent class analysis. Associations between comorbidity classes with demographic and outcome variables were evaluated using multinomial logistic and linear regressions, respectively.

RESULTS

TBI participants had a significantly higher comorbidity burden than controls, primarily driven by elevated rates of mental health disorders (RR=2.71, 95% confidence interval [1.37, 5.35]). Cardiovascular and physical health comorbidities were not elevated in the TBI group compared with controls. Both cohorts had 3 similar comorbidity subgroups, suggesting consistent patterns of co-occurring health conditions regardless of TBI exposure. Physical and mental health comorbidities were associated with elevated depression and anxiety symptoms and diminished HRQoL after TBI compared with controls.

CONCLUSION

TBI was associated with greater mental, but not physical, health comorbidities in the decades after injury. However, physical and mental health comorbidities significantly affected emotional and HRQoL status after TBI, underscoring a greater need for long-term support for individuals with TBI coping with both physical and mental health comorbidities.

From spreading depolarization to blood-brain barrier dysfunction: navigating traumatic brain injury for novel diagnosis and therapy

Considerable strides in medical interventions during the acute phase of traumatic brain injury (TBI) have brought improved overall survival rates. However, following TBI, people often face ongoing, persistent and debilitating long-term complications. Here, we review the recent literature to propose possible mechanisms that lead from TBI to long-term complications, focusing particularly on the involvement of a compromised blood-brain barrier (BBB). We discuss evidence for the role of spreading depolarization as a key pathological mechanism associated with microvascular dysfunction and the transformation of astrocytes to an inflammatory phenotype. Finally, we summarize new predictive and diagnostic biomarkers and explore potential therapeutic targets for treating long-term complications of TBI.

Cerebral hypoperfusion exacerbates traumatic brain injury in male but not female mice

Mild-moderate traumatic brain injuries (TBIs) are prevalent, and while many individuals recover, there is evidence that a significant number experience long-term health impacts, including increased vulnerability to neurodegenerative diseases. These effects are influenced by other risk factors, such as cardiovascular disease. Our study tested the hypothesis that a pre-injury reduction in cerebral blood flow (CBF), mimicking cardiovascular disease, worsens TBI recovery. We induced bilateral carotid artery stenosis (BCAS) and a mild-moderate closed-head TBI in male and female mice, either alone or in combination, and analyzed CBF, spatial learning, memory, axonal damage, and gene expression. Findings showed that BCAS and TBI independently caused a ~10% decrease in CBF. Mice subjected to both BCAS and TBI experienced more significant CBF reductions, notably affecting spatial learning and memory, particularly in males. Additionally, male mice showed increased axonal damage with both BCAS and TBI compared to either condition alone. Females exhibited spatial memory deficits due to BCAS, but these were not worsened by subsequent TBI. Gene expression analysis in male mice highlighted that TBI and BCAS individually altered neuronal and glial profiles. However, the combination of BCAS and TBI resulted in markedly different transcriptional patterns. Our results suggest that mild cerebrovascular impairments, serving as a stand-in for preexisting cardiovascular conditions, can significantly worsen TBI outcomes in males. This highlights the potential for mild comorbidities to modify TBI outcomes and increase the risk of secondary diseases.

Cardiorespiratory fitness assessment and training in the early sub-acute phase of recovery following traumatic brain injury: a systematic review

OBJECTIVES

To examine the safety of cardiorespiratory fitness (CRF) assessment and training in the early sub-acute phase of recovery (≤3 months) following moderate-to-extremely severe traumatic brain injury (TBI).

METHODS

A systematic review was completed in accordance with the PRISMA guidelines. Studies investigating adults and adolescents ≥15 years with moderate-to-extremely severe TBI were considered for inclusion. The methodological quality of the included studies was evaluated according to the McMaster Guidelines for Critical Review Form - Quantitative Studies.

RESULTS

Eleven studies with a total of 380 participants were included in the review. Adverse events (AEs) and symptom monitoring were poorly reported. Only four studies reported on the occurrence of AEs, with a total of eight AEs reported. Three of the reported AEs were concussion-like symptoms with no further exercise-induced symptom exacerbation reported. No serious AEs were reported.

CONCLUSION

There is no evidence to suggest that CRF assessment and training is unsafe in the early sub-acute phase of recovery following moderate-to-extremely severe TBI. However, despite the low AE and symptom exacerbation rates identified, a timeframe for safe commencement was unable to be established due to poor reporting and/or monitoring of exercise-induced symptoms and AEs in the current literature.

Concussion burden and later-life cardiovascular risk factors in former professional American-style football players

OBJECTIVE

Mid-life cardiovascular risk factors are associated with later cognitive decline. Whether repetitive head injury among professional athletes impacts cardiovascular risk is unknown. We investigated associations between concussion burden and postcareer hypertension, high cholesterol, and diabetes among former professional American-style football (ASF) players.

METHODS

In a cross-sectional study of 4080 professional ASF players conducted between January 2015 and March 2022, we used an mulitsymptom concussion symptom score (CSS) and the number of loss-of-consciousness (LOC) episodes as a single severe symptom to quantify football-related concussion exposure. Primary outcomes were hypertension, dyslipidemia, and diabetes, defined by current or recommended prescription medication use.

RESULTS

The prevalence of hypertension, high cholesterol, and diabetes among former players (52 ± 14 years of age) was 37%, 34%, and 9%. Concussion burden was significantly associated with hypertension (lowest vs. highest CSS quartile, odds ratio (OR) = 1.99; 95%CI: 1.33-2.98; p < 0.01) and high cholesterol (lowest vs. moderate CSS, OR = 1.46, 95%CI, 1.11-1.91; p < 0.01), but not diabetes. In fully adjusted models, the prevalence of multiple CVD was associated with CSS. These results were driven by younger former players (≤ 40 year of age) in which the odds of hypertension were over three times higher in those in the highest CSS quartile (OR = 3.29, 95%CI: 1.39-7.61; p = 0.01). Results were similar for LOC analyses.

INTERPRETATION

Prior concussion burden is associated with postcareer atherogenic cardiovascular risk profiles among former professional American football players.

Head Injury and Risk of Incident Ischemic Stroke in Community-Dwelling Adults

BACKGROUND

While stroke is a recognized short-term sequela of traumatic brain injury, evidence about long-term ischemic stroke risk after traumatic brain injury remains limited.

METHODS

The Atherosclerosis Risk in Communities Study is an ongoing prospective cohort comprised of US community-dwelling adults enrolled in 1987 to 1989 followed through 2019. Head injury was defined using self-report and hospital-based diagnostic codes and was analyzed as a time-varying exposure. Incident ischemic stroke events were physician-adjudicated. We used Cox regression adjusted for sociodemographic and cardiovascular risk factors to estimate the hazard of ischemic stroke as a function of head injury. Secondary analyses explored the number and severity of head injuries; the mechanism and severity of incident ischemic stroke; and heterogeneity within subgroups defined by race, sex, and age.

RESULTS

Our analysis included 12 813 participants with no prior head injury or stroke. The median follow-up age was 27.1 years (25th-75th percentile=21.1-30.5). Participants were of median age 54 years (25th-75th percentile=49-59) at baseline; 57.7% were female and 27.8% were Black. There were 2158 (16.8%) participants with at least 1 head injury and 1141 (8.9%) participants with an incident ischemic stroke during follow-up. For those with head injuries, the median age to ischemic stroke was 7.5 years (25th-75th percentile=2.2-14.0). In adjusted models, head injury was associated with an increased hazard of incident ischemic stroke (hazard ratio [HR], 1.34 [95% CI, 1.12-1.60]). We observed evidence of dose-response for the number of head injuries (1: HR, 1.16 [95% CI, 0.97-1.40]; ≥2: HR, 1.94 [95% CI, 1.39-2.71]) but not for injury severity. We observed evidence of stronger associations between head injury and more severe stroke (National Institutes of Health Stroke Scale score ≤5: HR, 1.31 [95% CI, 1.04-1.64]; National Institutes of Health Stroke Scale score 6-10: HR, 1.64 [95% CI, 1.06-2.52]; National Institutes of Health Stroke Scale score ≥11: HR, 1.80 [95% CI, 1.18-2.76]). Results were similar across stroke mechanism and within strata of race, sex, and age.

CONCLUSIONS

In this community-based cohort, head injury was associated with subsequent ischemic stroke. These results suggest the importance of public health interventions aimed at preventing head injuries and primary stroke prevention among individuals with prior traumatic brain injuries.

Exploring cerebral structural and functional abnormalities in a mouse model of post-traumatic headache induced by mild traumatic brain injury

Mild traumatic brain injury (mTBI)-induced post-traumatic headache (PTH) is a pressing public health concern and leading cause of disability worldwide. Although PTH is often accompanied by neurological disorders, the exact underlying mechanism remains largely unknown. Identifying potential biomarkers may prompt the diagnosis and development of effective treatments for mTBI-induced PTH. In this study, a mouse model of mTBI-induced PTH was established to investigate its effects on cerebral structure and function during short-term recovery. Results indicated that mice with mTBI-induced PTH exhibited balance deficits during the early post-injury stage. Metabolic kinetics revealed that variations in neurotransmitters were most prominent in the cerebellum, temporal lobe/cortex, and hippocampal regions during the early stages of PTH. Additionally, variations in brain functional activities and connectivity were further detected in the early stage of PTH, particularly in the cerebellum and temporal cortex, suggesting that these regions play central roles in the mechanism underlying PTH. Moreover, our results suggested that GABA and glutamate may serve as potential diagnostic or prognostic biomarkers for PTH. Future studies should explore the specific neural circuits involved in the regulation of PTH by the cerebellum and temporal cortex, with these two regions potentially utilized as targets for non-invasive stimulation in future clinical treatment.

Prevalence of Cardiovascular Conditions After Traumatic Brain Injury: A Comparison Between the Traumatic Brain Injury Model Systems and the National Health and Nutrition Examination Survey

BACKGROUND

The purpose of this study is to compare the prevalence of self-reported cardiovascular conditions among individuals with moderate to severe traumatic brain injury (TBI) to a propensity-matched control cohort.

METHODS AND RESULTS

A cross-sectional study described self-reported cardiovascular conditions (hypertension, congestive heart failure [CHF], myocardial infarction [MI], and stroke) from participants who completed interviews between January 2015 and March 2020 in 2 harmonized large cohort studies, the TBI Model Systems and the National Health and Nutrition Examination Survey. Mixed-effect logistic regression models were used to compare the prevalence of cardiovascular conditions after 1:1 propensity-score matching based on age, sex, race, ethnicity, body mass index, education level, and smoking status. The final sample was 4690 matched pairs. Individuals with TBI were more likely to report hypertension (odds ratio [OR], 1.18 [95% CI, 1.08-1.28]) and stroke (OR, 1.70 [95% CI, 1.56-1.98]) but less likely to report CHF (OR, 0.81 [95% CI, 0.67-0.99]) or MI (OR, 0.66 [95% CI, 0.55-0.79]). There was no difference in rate of CHF or MI for those ≤50 years old; however, rates of CHF and MI were lower in the TBI group for individuals >50 years old. Over 65% of individuals who died before the first follow-up interview at 1 year post-TBI were >50 years old, and those >50 years old were more likely to die of heart disease than those ≤50 years old (17.6% versus 8.6%).

CONCLUSIONS

Individuals with moderate to severe TBI had an increased rate of self-reported hypertension and stroke but lower rate of MI and CHF than uninjured adults, which may be due to survival bias.

High-salt diet induces microbiome dysregulation, neuroinflammation and anxiety in the chronic period after mild repetitive closed head injury in adolescent mice

The associations between human concussions and subsequent sequelae of chronic neuropsychiatric and cardiovascular diseases such as hypertension have been reported; however, little is known about the underlying biological processes. We hypothesized that dietary changes, including a high-salt diet, disrupt the bidirectional gut-brain axis, resulting in worsening neuroinflammation and emergence of cardiovascular and behavioural phenotypes in the chronic period after repetitive closed head injury in adolescent mice. Adolescent mice were subjected to three daily closed head injuries, recovered for 12 weeks and then maintained on a high-salt diet or a normal diet for an additional 12 weeks. Experimental endpoints were haemodynamics, behaviour, microglial gene expression (bulk RNA sequencing), brain inflammation (brain tissue quantitative PCR) and microbiome diversity (16S RNA sequencing). High-salt diet did not affect systemic blood pressure or heart rate in sham or injured mice. High-salt diet increased anxiety-like behaviour in injured mice compared to sham mice fed with high-salt diet and injured mice fed with normal diet. Increased anxiety in injured mice that received a high-salt diet was associated with microgliosis and a proinflammatory microglial transcriptomic signature, including upregulation in interferon-gamma, interferon-beta and oxidative stress-related pathways. Accordingly, we found upregulation of tumour necrosis factor-alpha and interferon-gamma mRNA in the brain tissue of high salt diet-fed injured mice. High-salt diet had a larger effect on the gut microbiome composition than repetitive closed head injury. Increases in gut microbes in the families Lachnospiraceae, Erysipelotrichaceae and Clostridiaceae were positively correlated with anxiety-like behaviours. In contrast, Muribaculaceae, Acholeplasmataceae and Lactobacillaceae were negatively correlated with anxiety in injured mice that received a high-salt diet, a time-dependent effect. The findings suggest that high-salt diet, administered after a recovery period, may affect neurologic outcomes following mild repetitive head injury, including the development of anxiety. This effect was linked to microbiome dysregulation and an exacerbation of microglial inflammation, which may be physiological targets to prevent behavioural sequelae in the chronic period after mild repetitive head injury. The data suggest an important contribution of diet in determining long-term outcomes after mild repetitive head injury.

Incidence of Traumatic Brain Injury in a Longitudinal Cohort of Older Adults

Importance

Traumatic brain injury (TBI) occurs at the highest rate in older adulthood and increases risk for cognitive impairment and dementia.

Objectives

To update existing TBI surveillance data to capture nonhospital settings and to explore how social determinants of health (SDOH) are associated with TBI incidence among older adults.

Design, Setting, and Participants

This nationally representative longitudinal cohort study assessed participants for 18 years, from August 2000 through December 2018, using data from the Health and Retirement Study (HRS) and linked Medicare claims dates. Analyses were completed August 9 through December 12, 2022. Participants were 65 years of age or older in the HRS with survey data linked to Medicare without a TBI prior to HRS enrollment. They were community dwelling at enrollment but were retained in HRS if they were later institutionalized.

Exposures

Baseline demographic, cognitive, medical, and SDOH information from HRS.

Main Outcomes and Measures

Incident TBI was defined using inpatient and outpatient International Classification of Diseases, Ninth or Tenth Revision, diagnosis codes received the same day or within 1 day as the emergency department (ED) visit code and the computed tomography (CT) or magnetic resonance imaging (MRI) code, after baseline HRS interview. A cohort with TBI codes but no ED visit or CT or MRI scan was derived to capture diagnoses in nonhospital settings. Descriptive statistics and bivariate associations of TBI with demographic and SDOH characteristics used sample weights. Fine-Gray regression models estimated associations between covariates and TBI, with death as a competing risk. Imputation considering outcome and complex survey design was performed by race and ethnicity, sex, education level, and Area Deprivation Index percentiles 1, 50, and 100. Other exposure variables were fixed at their weighted means.

Results

Among 9239 eligible respondents, 5258 (57.7%) were female and 1210 (9.1%) were Black, 574 (4.7%) were Hispanic, and 7297 (84.4%) were White. Mean (SD) baseline age was 75.2 (8.0) years. During follow-up (18 years), 797 (8.9%) of respondents received an incident TBI diagnosis with an ED visit and a CT code within 1 day, 964 (10.2%) received an incident TBI diagnosis and an ED code, and 1148 (12.9%) received a TBI code with or without an ED visit and CT scan code. Compared with respondents without incident TBI, respondents with TBI were more likely to be female (absolute difference, 7.0 [95% CI, 3.3-10.8]; P < .001) and White (absolute difference, 5.1 [95% CI, 2.8-7.4]; P < .001), have normal cognition (vs cognitive impairment or dementia; absolute difference, 6.1 [95% CI, 2.8-9.3]; P = .001), higher education (absolute difference, 3.8 [95% CI, 0.9-6.7]; P < .001), and wealth (absolute difference, 6.5 [95% CI, 2.3-10.7]; P = .01), and be without baseline lung disease (absolute difference, 5.1 [95% CI, 3.0-7.2]; P < .001) or functional impairment (absolute difference, 3.3 [95% CI, 0.4-6.1]; P = .03). In adjusted multivariate models, lower education (subdistribution hazard ratio [SHR], 0.73 [95% CI, 0.57-0.94]; P = .01), Black race (SHR, 0.61 [95% CI, 0.46-0.80]; P < .001), area deprivation index national rank (SHR 1.00 [95% CI 0.99-1.00]; P = .009), and male sex (SHR, 0.73 [95% CI, 0.56-0.94]; P = .02) were associated with membership in the group without TBI. Sensitivity analyses using a broader definition of TBI yielded similar results.

Conclusions and Relevance

In this longitudinal cohort study of older adults, almost 13% experienced incident TBI during the 18-year study period. For older adults who seek care for TBI, race and ethnicity, sex, and SDOH factors may be associated with incidence of TBI, seeking medical attention for TBI in older adulthood, or both.

Risk of Long-Term Ischemic Stroke in Patients With Traumatic Brain Injury and Incident Hypertension

Traumatic brain injury (TBI) is independently associated with hypertension and ischemic stroke. The goal of this study was to determine the interplay between TBI and incident hypertension in the occurrence of post-TBI stroke. This prospective study used a hospital-based registry to identify patients without pre-existing comorbidities. TBI patients (n = 3664) were frequency matched on age, sex, and race to non-TBI patients (n = 1848). Follow-up started 6 months post-TBI or study entry and extended up to 10 years. To examine hypertension's role in post-TBI stroke, we used logistic regression models to calculate the effect estimates for stroke in four exposure categories that included TBI or hypertension in isolation and in combination. Second, we calculated the conditional direct effect (CDE) of TBI in models that considered hypertension as intermediary. Third, we examined whether TBI effect was modified by antihypertensive medication use. The 10-year cumulative incidence of stroke was higher in the TBI group (4.7%) than the non-TBI group (1.3%; p < 0.001). TBI patients who developed hypertension had the highest risk of stroke (odds ratio [OR] = 4.83, 95% confidence interval [CI] = 2.53-9.23, p < 0.001). The combined effect estimates were less than additive, suggesting an overlapping biological pathway. The total effect of TBI (OR = 3.16, 95% CI = 1.94-5.16, p < 0.001) was higher than the CDE that accounted for hypertension (OR = 2.45, 95% CI = 0.93-6.47, p = 0.06). Antihypertensives attenuated the TBI effect, suggesting that the TBI effect on stroke is partially mediated through hypertension. TBI is an independent risk factor for long-term stroke, and the underlying biological pathway may partly operate through TBI-precipitated hypertension. These findings suggest that screening for hypertension may mitigate stroke risk in TBI.

iPad-Based Neurocognitive Testing (ImPACT-QT) in Acute Adult Mild Traumatic Brain Injury/Concussion: Study on Practicality and Bedside Cognitive Scores in a Level-1 Trauma Center

BACKGROUND

There lacks rapid standardized bedside testing to screen cognitive deficits following mild traumatic brain injury (mTBI). Immediate Post-Concussion Assessment & Cognitive Testing-Quick Test (ImPACT-QT) is an abbreviated-iPad form of computerized cognitive testing. The aim of this study is to test ImPACT-QT utility in inpatient settings. We hypothesize ImPACT-QT is feasible in the acute trauma setting.

METHOD

Trauma patients ages 12-70 were administered ImPACT-QT (09/2022-09/2023). Encephalopathic/medically unstable patients were excluded. Mild traumatic brain injury was defined as documented-head trauma with loss-of-consciousness <30 minutes and arrival Glasgow Coma Scale 13-15. Patients answered Likert-scale surveys. Bivariate analyses compared demographics, attention, motor speed, and memory scores between mTBI and non-TBI controls. Multivariable logistic regression assessed memory score as a predictor of mTBI diagnosis.

RESULTS

Of 233 patients evaluated (36 years [IQR 23-50], 71% [166/233] female), 179 (76%) were mTBI patients. For all patients, mean test-time was 9.3 ± 2 minutes with 93% (73/76) finding the test "easy to understand." Mild traumatic brain injury patients than non-TBI control had lower memory scores (25 [IQR 7-100] vs 43 [26-100], P = .001) while attention (5 [1-23] vs 11 [1-32]) and motor score (14 [3-28] vs 13 [4-32]) showed no significant differences. Multivariable-regression (adjustment: age, sex, race, education level, ISS, and time to test) demonstrated memory score predicted mTBI positive status (OR .96, CI .94-.98, P = .004).

DISCUSSION

Immediate Post-Concussion Assessment & Cognitive Testing-Quick Test is feasible in trauma patients. Preliminary findings suggest acute mTBIs have lower memory but not attention/motor scores vs non-TBI trauma controls.

Racial/Ethnic and Geographic Disparities in Comorbid Traumatic Brain Injury-Renal Failure in US Veterans and Associated Veterans Affairs Resource Costs, 2000-2020

Studies have identified disparities by race/ethnicity and geographic status among veterans with traumatic brain injury (TBI) and renal failure (RF). We examined the association of race/ethnicity and geographic status with RF onset in veterans with and without TBI, and the impact of disparities on Veterans Health Administration resource costs.

METHODS

Demographics by TBI and RF status were assessed. We estimated Cox proportional hazards models for progression to RF and generalized estimating equations for inpatient, outpatient, and pharmacy cost annually and time since TBI + RF diagnosis, stratified by age.

RESULTS

Among 596,189 veterans, veterans with TBI progressed faster to RF than those without TBI (HR 1.96). Non-Hispanic Black veterans (HR 1.41) and those in US territories (HR 1.71) progressed faster to RF relative to non-Hispanic Whites and those in urban mainland areas. Non-Hispanic Blacks (-$5,180), Hispanic/Latinos ($-4,984), and veterans in US territories (-$3,740) received fewer annual total VA resources. This was true for all Hispanic/Latinos, while only significant for non-Hispanic Black and US territory veterans < 65 years. For veterans with TBI + RF, higher total resource costs only occurred ≥ 10 years after TBI + RF diagnosis ($32,361), independent of age. Hispanic/Latino veterans ≥ 65 years received $8,248 less than non-Hispanic Whites and veterans living in US territories < 65 years received $37,514 less relative to urban veterans.

CONCLUSION

Concerted efforts to address RF progression in veterans with TBI, especially in non-Hispanic Blacks and those in US territories, are needed. Importantly, culturally appropriate interventions to improve access to care for these groups should be a priority of the Department of Veterans Affairs priority for these groups.

Comparative Efficacy of High-Intensity Training Versus Conventional Training in Individuals With Chronic Traumatic Brain Injury: A Pilot Randomized Controlled Study

Numerous studies have evaluated the efficacy of interventions to improve locomotion after acute-onset brain injury, although most focus on patients with stroke, with less attention toward traumatic brain injury (TBI). For example, a number of studies in patients post-stroke have evaluated the effects of high-intensity training (HIT) attempting to maximize stepping practice, while no studies have attempted this intervention in patients with TBI. The purpose of this blinded-assessor randomized trial was to evaluate the effects of HIT focused on stepping practice versus conventional training on walking and secondary outcomes in individuals with TBI. Using a crossover design, ambulatory participants with TBI >6-months duration performed HIT focused on stepping in variable contexts (overground, treadmill, stairs) or conventional training for up to 15 sessions over five weeks, with interventions alternated >4 weeks later. HIT focused on maximizing stepping practice while trying to achieve higher cardiovascular intensities (>70% heart rate reserve), while conventional training focused on impairment-based and functional exercises with no restrictions on intensities achieved. Greater increases in 6-min walk test and peak treadmill speed during graded exercise testing were observed after HIT versus conventional training, with moderate associations between differences in stepping practice and outcomes. Greater gains were also observed in estimates of aerobic capacity and efficiency after HIT, with additional improvements in selected cognitive assessments. The present study suggests that the amount and intensity of stepping practice may be important determinants of improved locomotor outcomes in patients with chronic TBI, with possible secondary benefits on aerobic capacity/efficiency and cognition. Clinical Trial Registration-URL: https://clinicaltrials.gov/; Unique Identifier: NCT04503473.

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.

Pulmonary Effects of Traumatic Brain Injury in Mice: A Gene Set Enrichment Analysis

Acute lung injury occurs in 20-25% of cases following traumatic brain injury (TBI). We investigated changes in lung transcriptome expression post-TBI using animal models and bioinformatics. Employing unilateral controlled cortical impact for TBI, we conducted microarray analysis after lung acquisition, followed by gene set enrichment analysis of differentially expressed genes. Our findings indicate significant upregulation of inflammation-related genes and downregulation of nervous system genes. There was enhanced infiltration of adaptive immune cells, evidenced by positive enrichment in Lung-Th1, CD4, and CD8 T cells. Analysis using the Tabula Sapiens database revealed enrichment in lung-adventitial cells, pericytes, myofibroblasts, and fibroblasts, indicating potential effects on lung vasculature and fibrosis. Gene set enrichment analysis linked TBI to lung diseases, notably idiopathic pulmonary hypertension. A Venn diagram overlap analysis identified a common set of 20 genes, with FOSL2 showing the most significant fold change. Additionally, we observed a significant increase in ADRA1A→IL6 production post-TBI using the L1000 library. Our study highlights the impact of brain trauma on lung injury, revealing crucial gene expression changes related to immune cell infiltration, cytokine production, and potential alterations in lung vasculature and fibrosis, along with a specific spectrum of disease influence.

Exploring Interactions Between Traumatic Brain Injury History and Gender on Medical Comorbidities in Military Veterans: An Epidemiological Analysis in the VA Million Veteran Program

Epidemiological studies of medical comorbidities and possible gender differences associated with traumatic brain injury (TBI) are limited, especially among military veterans. The purpose of this study was to examine relationships between TBI history and a wide range of medical conditions in a large, national sample of veterans, and to explore interactions with gender. Participants of this cross-sectional epidemiological study included 491,604 veterans (9.9% TBI cases; 8.3% women) who enrolled in the VA Million Veteran Program (MVP). Outcomes of interest were medical comorbidities (i.e., neurological, mental health, circulatory, and other medical conditions) assessed using the MVP Baseline Survey, a self-report questionnaire. Logistic regression models adjusting for age and gender showed that veterans with TBI history consistently had significantly higher rates of medical comorbidities than controls, with the greatest differences observed across mental health (odds ratios [ORs] = 2.10-3.61) and neurological (ORs = 1.57-6.08) conditions. Similar patterns were found when evaluating men and women separately. Additionally, significant TBI-by-gender interactions were observed, particularly for mental health and neurological comorbidities, such that men with a history of TBI had greater odds of having several of these conditions than women with a history of TBI. These findings highlight the array of medical comorbidities experienced by veterans with a history of TBI, and illustrate that clinical outcomes differ for men and women with TBI history. Although these results are clinically informative, more research is needed to better understand the role of gender on health conditions in the context of TBI and how gender interacts with other social and cultural factors to influence clinical trajectories following TBI. Ultimately, understanding the biological, psychological, and social mechanisms underlying these comorbidities may help with tailoring TBI treatment by gender and improve quality of life for veterans with TBI history.

Traumatic Brain Injury, Psychological Trauma Exposure, and Anxious and Depressive Symptoms in a Clinical Population

BACKGROUND

Approximately 90% of adults endorse psychological trauma exposure. However, barriers to assessment of psychological trauma and sequelae include limited access to care, lack of standardized assessments in nonpsychiatric settings, and comorbid diagnoses, such as traumatic brain injury (TBI), that may mimic psychiatric syndromes.

OBJECTIVES

This study aims to assess the prevalence rates of psychological trauma exposure and TBI to understand the relationship of these experiences with current psychiatric symptoms.

METHODS

This is a cross-sectional study of a convenience sample of adult patients (age 18 years and older) referred for outpatient evaluation at a neuropsychology clinic in the Western United States between September 2021 and October 2022. Patients completed a clinical interview to assess their history of psychological trauma, TBI, and current psychiatric symptoms.

RESULTS

A total of 118 patients met inclusion criteria. Patients in the TBI group (n = 83) endorsed significantly higher rates of childhood trauma and prior physical, emotional, and sexual abuse compared with the No TBI group (n = 35). Psychological trauma exposure and TBI significantly predicted current anxiety and depressive symptoms, but there was no interaction between these experiences in predicting current psychiatric symptoms.

CONCLUSIONS

Individuals with prior TBI experienced psychological trauma, particularly childhood trauma, at a significantly higher rate than those without TBI. Psychological trauma exposure and TBI independently predicted anxious and depressive symptoms, suggesting both may be viable treatment targets. Evaluation of prior psychological trauma exposure during evaluation of TBI may provide opportunities for trauma-informed care and may allow for improved outpatient treatment planning.

[Dementia Prevention]

Dementia is common and will continue to grow in importance and numbers in the future. However, as causal treatment is not possible in most cases, prevention is particularly important. This is not only aimed at cognitively healthy people, but is also a central element in all phases of the disease.

Associations Between Head Injury, Strangulation, Cardiometabolic Health, and Functional Disability Among Female Survivors of Intimate Partner Violence

OBJECTIVE

Head injury and strangulation are highly prevalent in intimate partner violence (IPV) contexts, but there is little research examining the potential implications of these injuries on physical health and functional status. This pilot study explored the extent to which injury type (head injury, strangulation) and severity (no injury, subconcussive head injury, traumatic brain injury; no strangulation, strangulation, strangulation with loss of consciousness) were associated with biomarkers of cardiometabolic health and self-reported functioning among female survivors of IPV.

METHODS

Participants were 51 individuals assigned female at birth who experienced IPV during their lifetime and screened positive for probable posttraumatic stress disorder (PTSD) on the PTSD Checklist for DSM-5 (average age = 32.6 years, SD = 7.1).

RESULTS

Head injury was associated with statistically significant increases in blood glucose levels (p = .01, d = 1.10). Shifts toward more high-risk values with moderate-strong effect sizes were also found in high-density lipoprotein, low-density lipoprotein, and waist-to-hip ratio (ps: .06-.13; ds: 0.51-1.30). Strangulation was associated with increased cholesterol levels, with a moderate effect size (p = .20, d = 0.59). Regression models accounting for age, education, PTSD symptoms, childhood trauma, strangulation, and head injuries predicted functional disability status (R2 = 0.37, p < .01) and several of its associated domains: cognition (R2 = 0.34, F(8,42) = 2.73, p = .01), mobility (R2 = 0.47, F(8,42) = 4.82, p < .001), and participation in society (R2 = 0.33, F(8,42) = 2.59, p = .02).

CONCLUSIONS

Findings suggest the need to develop integrated treatments that address physical health comorbidities among female survivors of IPV with a history of head injury to improve daily function and quality of life.

The Temporal Relationship Between Moderate to Vigorous Physical Activity and Secondary Conditions During the First Year After Moderate to Severe Traumatic Brain Injury

OBJECTIVE

To determine the cross-sectional and temporal relationships between minutes per week of moderate to vigorous physical activity (MVPA) as measured by a wrist-worn accelerometer and secondary conditions in the first year after moderate to severe traumatic brain injury (TBI).

DESIGN

Prospective longitudinal cohort study.

SETTING

Four inpatient rehabilitation centers.

PARTICIPANTS

Individuals (N = 180) with moderate-severe TBI enrolled in the TBI Model Systems Study.

INTERVENTIONS

Participants wore a wrist accelerometer for 7 days immediately post discharge, and for 7 consecutive days at 6- and 12-months post injury.

MAIN OUTCOME MEASURES

Minutes per week of MVPA from daily averages based on wrist worn accelerometer. Secondary conditions included depression (Patient Health Questionnaire-9), fatigue (PROMIS Fatigue), Pain (Numeric Rating Scale), Sleep (Pittsburgh Sleep Quality Index), and cognition (Brief Test of Adult Cognition by Telephone).

RESULTS

At baseline, 6 and 12 months, 61%, 70% and 79% of the sample achieved at least 150 minutes per week of MVPA. The correlations between minutes of MVPA between baseline, 6 and 12 months were significant (r = 0.53-0.73), as were secondary conditions over these time points. However, no significant correlations were observed between minutes of MVPA and any secondary outcomes cross-sectionally or longitudinally at any time point.

CONCLUSIONS

Given the robust relationships physical activity has with outcomes in the general population, further research is needed to understand the effect of physical activity in individuals with moderate-severe TBI.

The Relationship of Health Literacy to Health Outcomes Among Individuals With Traumatic Brain Injury: A Traumatic Brain Injury Model Systems Study

OBJECTIVE

To examine the associations between health literacy and health outcomes among individuals with traumatic brain injury (TBI) at least a year post-injury.

SETTING

Community following discharge from inpatient rehabilitation.

PARTICIPANTS

A total of 205 individuals with complicated mild to severe TBI who completed a TBI Model Systems National Database follow-up interview and a web-based health literacy measure.

DESIGN

A multicenter, cross-sectional, observational study.

MAIN MEASURES

The Health Literacy Assessment Using Talking Touchscreen Technology (Health LiTT), number of comorbid conditions (Medical and Mental Health Comorbidities Interview [MMHCI]), perceived physical and mental health (PROMIS Global Physical and Mental Health subscales), Patient Health Questionnaire-9 (PHQ-9), and Generalized Anxiety Disorder-7 (GAD-7).

RESULTS

After controlling for sociodemographic, injury, cognition, and time post-injury, adequate health literacy was associated with higher odds of greater perceived physical health compared with participants with marginal/inadequate health literacy (odds ratio = 4.10; CI = 1.52-11.70]. Participants with inadequate/marginal health literacy had 3.50 times greater odds of depression (PHQ-9 ≥ 10) compared with those with adequate health literacy. Participants 45 years and older reported a greater number of MMHCI physical health conditions, but fewer MMHCI mental health conditions and GAD-7 anxiety symptoms compared with those who were younger. Non-Hispanic White participants and those with mild/moderate TBI were more likely to report a greater number of MMHCI mental health conditions compared with non-Hispanic Black participants or those with severe TBI. Greater time post-injury was associated with greater number of chronic physical and mental health conditions, and less odds of good-to-excellent perceived global mental health.

CONCLUSIONS

Inadequate health literacy is associated with worse perceived physical health and greater depressive symptoms among adults with TBI. Greater efforts are needed to explore the mechanisms by which health literacy influences chronic disease management and mental health after TBI to improve postinjury health status and outcomes, particularly among those with limited health literacy skills.

Cognitive and psychiatric adverse events during adjunctive cenobamate treatment in phase 2 and phase 3 clinical studies

OBJECTIVE

Cognitive and psychiatric adverse events in patients with epilepsy are important determinants of therapeutic outcomes and patient quality of life. We assessed the relationship between adjunctive cenobamate treatment and selected cognitive and psychiatric treatment-emergent adverse events (TEAEs) in adults with uncontrolled focal epilepsy.

METHODS

This was a retrospective analysis of pooled populations of patients with focal epilepsy from two phase 2, randomized, double-blind clinical trials; two open-label extensions (OLEs) of those trials; and a long-term, open-label, phase 3 safety study. Occurrence of cognitive and psychiatric TEAEs in patients treated with adjunctive cenobamate or placebo during double-blind treatment were evaluated. Exposure-adjusted incidence rates of the cognitive and psychiatric TEAEs, defined as the number of TEAEs per patient-year of treatment, during up to 7 years of long-term adjunctive cenobamate treatment, were determined in the pooled OLE and phase 3 patient populations.

RESULTS

The pooled randomized trials resulted in a population of 442 patients treated with cenobamate (100 mg/day: n = 108; 200 mg/day: n = 223; 400 mg/day: n = 111) and 216 placebo-treated patients. The combined open-label studies resulted in pooled populations of cenobamate-treated patients ranging from n = 1690 during Year 1 to n = 103 during Year 7. Among cenobamate-treated (all doses) and placebo-treated patients during double-blind treatment, cognitive TEAEs were reported by ≤ 1.9 % (range, 0 %-1.9 %) and ≤ 0.5 % (range, 0 %-0.5 %), respectively, and psychiatric TEAEs by ≤ 3.6 % (range, 0 %-3.6 %) and ≤ 3.2 % (range, 0 %-3.2 %), respectively. During up to 7 years of open-label adjunctive cenobamate treatment, exposure-adjusted incidence rates of cognitive and psychiatric TEAEs were < 0.018 and < 0.038 events per patient-year, respectively. Discontinuation of adjunctive cenobamate due to cognitive or psychiatric TEAEs assessed in this study during double-blind or open-label treatment occurred in ≤ 0.3 % and ≤ 1.7 % of patients, respectively.

CONCLUSIONS

Cognitive and psychiatric TEAEs were reported by similar numbers of cenobamate- and placebo-treated patients during double-blind adjunctive cenobamate treatment (< 4 % of patients), and exposure-adjusted incidence rates of these TEAEs remained low during open-label cenobamate treatment for up to 7 years. Treatment discontinuations due to these TEAEs were rare. The results of this post-hoc analysis indicate that adjunctive cenobamate treatment exhibits a low incidence of cognitive or psychiatric TEAEs in patients with uncontrolled focal seizures.

A qualitative longitudinal study of traumatic orthopaedic injury survivors' experiences with pain and the long-term recovery trajectory

OBJECTIVES

To explore trauma patients' experiences of the long-term recovery pathway during 18 months following hospital discharge.

DESIGN

Longitudinal qualitative study.

SETTING AND PARTICIPANTS

Thirteen trauma patients with injuries associated with pain that had been interviewed 6 weeks after discharge from Oslo University Hospital in Norway, were followed up with an interview 18 months postdischarge.

METHOD

The illness trajectory framework informed the data collection, with semistructured, in-depth interviews that were analysed thematically.

RESULTS

Compared with the subacute phase 6 weeks postdischarge, several participants reported exacerbated mental and physical health, including increased pain during 18 months following discharge. This, andalternating periods of deteriorated health status during recovery, made the pathway unpredictable. At 18 months post-discharge, participants were coping with experiences of reduced mental and physical health and socioeconomic losses. Three main themes were identified: (1) coping with persistent pain and reduced physical function, (2) experiencing mental distress without access to mental healthcare and (3) unmet needs for follow-up care. Moreover, at 18 months postdischarge, prescribed opioids were found to be easily accessible from GPs. In addition to relieving chronic pain, motivations to use opioids were to induce sleep, reduce withdrawal symptoms and relieve mental distress.

CONCLUSIONS AND IMPLICATIONS

The patients' experiences from this study establish knowledge of several challenges in the trauma population's recovery trajectories, which may imply that subacute health status is a poor predictor of long-term outcomes. Throughout recovery, the participants struggled with physical and mental health needs without being met by the healthcare system. Therefore, it is necessary to provide long-term follow-up of trauma patients' health status in the specialist health service based on individual needs. Additionally, to prevent long-term opioid use beyond the subacute phase, there is a need to systematically follow-up and reassess motivations and indications for continued use throughout the recovery pathway.

Elucidating the neuroimmunology of traumatic brain injury: methodological approaches to unravel intercellular communication and function

The neuroimmunology of traumatic brain injury (TBI) has recently gained recognition as a crucial element in the secondary pathophysiological consequences that occur following neurotrauma. Both immune cells residing within the central nervous system (CNS) and those migrating from the periphery play significant roles in the development of secondary brain injury. However, the precise mechanisms governing communication between innate and adaptive immune cells remain incompletely understood, partly due to a limited utilization of relevant experimental models and techniques. Therefore, in this discussion, we outline current methodologies that can aid in the exploration of TBI neuroimmunology, with a particular emphasis on the interactions between resident neuroglial cells and recruited lymphocytes. These techniques encompass adoptive cell transfer, intra-CNS injection(s), selective cellular depletion, genetic manipulation, molecular neuroimaging, as well as in vitro co-culture systems and the utilization of organoid models. By incorporating key elements of both innate and adaptive immunity, these methods facilitate the examination of clinically relevant interactions. In addition to these preclinical approaches, we also detail an emerging avenue of research that seeks to leverage human biofluids. This approach enables the investigation of how resident and infiltrating immune cells modulate neuroglial responses after TBI. Considering the growing significance of neuroinflammation in TBI, the introduction and application of advanced methodologies will be pivotal in advancing translational research in this field.

Traumatic brain injury and risk of heart failure and coronary heart disease: A nationwide population-based cohort study

BACKGROUND

This study examined the long-term risks of heart failure (HF) and coronary heart disease (CHD) following traumatic brain injury (TBI), focusing on gender differences.

METHODS

Data from Taiwan's National Health Insurance Research Database included 29,570 TBI patients and 118,280 matched controls based on propensity scores.

RESULTS

The TBI cohort had higher incidences of CHD and HF (9.76 vs. 9.07 per 1000 person-years; 4.40 vs. 3.88 per 1000 person-years). Adjusted analyses showed a significantly higher risk of HF in the TBI group (adjusted hazard ratio = 1.08, 95% CI = 1.01-1.17, P = 0.031). The increased CHD risk in the TBI cohort became insignificant after adjustment. Subgroup analysis by gender revealed higher HF risk in men (aHR = 1.14, 95% CI = 1.03-1.25, P = 0.010) and higher CHD risk in women under 50 (aHR = 1.32, 95% CI = 1.15-1.52, P < 0.001). TBI patients without beta-blocker therapy may be at increased risk of HF.

CONCLUSION

Our results suggest that TBI increases the risk of HF and CHD in this nationwide cohort of Taiwanese citizens. Gender influences the risks differently, with men at higher HF risk and younger women at higher CHD risk. Beta-blockers have a neutral effect on HF and CHD risk.

Clinical complications after a traumatic brain injury and its relation with brain biomarkers

We aimed to find out which are the most frequent complications for patients who suffer a traumatic brain injury (TBI) and its relation with brain biomarker levels. We conducted a hospital cohort study with patients who attended the Hospital Emergency Department between 1 June 2018 and 31 December 2020. Different variables were collected such as biomarkers levels after 6 h and 12 h of TBI (S100, NSE, UCHL1 and GFAP), clinical and sociodemographic variables, complementary tests, and complications 48 h and 7 days after TBI. Qualitative variables were analysed with Pearson's chi-square test, and quantitative variables with the Mann-Whitney U test. A multivariate logistic regression model for the existence of complications one week after discharge was performed to assess the discriminatory capacity of the clinical variables. A total of 51 controls and 540 patients were included in this study. In the TBI group, the mean age was 83 years, and 53.9% of the patients were male. Complications at seven days were associated with the severity of TBI (p < 0.05) and the number of platelets (p = 0.016). All biomarkers except GFAP showed significant differences in their distribution of values according to gender, with significantly higher values of the three biomarkers for women with respect to men. Patients with complications presented significantly higher S100 values (p < 0.05). The patient's baseline status, the severity of the TBI and the S100 levels can be very important elements in determining whether a patient may develop complications in the few hours after TBI.

The Hypothalamus-pituitary-adrenocortical Response to Critical Illness: A Concept in Need of Revision

Based on insights obtained during the past decade, the classical concept of an activated hypothalamus-pituitary-adrenocortical axis in response to critical illness is in need of revision. After a brief central hypothalamus-pituitary-adrenocortical axis activation, the vital maintenance of increased systemic cortisol availability and action in response to critical illness is predominantly driven by peripheral adaptations rather than by an ongoing centrally activated several-fold increased production and secretion of cortisol. Besides the known reduction of cortisol-binding proteins that increases free cortisol, these peripheral responses comprise suppressed cortisol metabolism in liver and kidney, prolonging cortisol half-life, and local alterations in expression of 11βHSD1, glucocorticoid receptor-α (GRα), and FK506 binding protein 5 (FKBP51) that appear to titrate increased GRα action in vital organs and tissues while reducing GRα action in neutrophils, possibly preventing immune-suppressive off-target effects of increased systemic cortisol availability. Peripherally increased cortisol exerts negative feed-back inhibition at the pituitary level impairing processing of pro-opiomelanocortin into ACTH, thereby reducing ACTH-driven cortisol secretion, whereas ongoing central activation results in increased circulating pro-opiomelanocortin. These alterations seem adaptive and beneficial for the host in the short term. However, as a consequence, patients with prolonged critical illness who require intensive care for weeks or longer may develop a form of central adrenal insufficiency. The new findings supersede earlier concepts such as "relative," as opposed to "absolute," adrenal insufficiency and generalized systemic glucocorticoid resistance in the critically ill. The findings also question the scientific basis for broad implementation of stress dose hydrocortisone treatment of patients suffering from acute septic shock solely based on assumption of cortisol insufficiency.

Identification of Factors in Moderate-Severe TBI Related to a Functional Decline in Cognition Decades After Injury

OBJECTIVE

To investigate whether a functional decline in cognitive activities decades after moderate-to-severe traumatic brain injury (m-sTBI) might relate to injury features and/or lifetime health factors, some of which may emerge as consequences of the injury.

DESIGN

Secondary analysis of the TBI Model Systems National Database, a prospective, multi-center, longitudinal study of patients with m-sTBI.

SETTING

TBI Model Systems Centers.

PARTICIPANTS

Included were 732 participants rated on the cognitive subscale of the Functional Independence Measure (FIM Cognitive), a metric for everyday cognitive skills, across 3 time points out to 20 years (visits at 2-, 10-, and 20-year follow-ups; N=732).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

FIM Cognitive Scale. Injury characteristics such as timing and features pertaining to severity and health-related factors (eg, alcohol use, socioeconomic status) were examined to discriminate stable from declining participants on the FIM Cognitive Scale using logistic regression.

RESULTS

At 20 years post-injury, there was a low base rate of FIM Cognitive decline (11%, n=78), with most being stable or having meaningful improvement (89%, n=654). Older age at injury, longer duration of post-traumatic amnesia, and presence of repetitive seizures were significant predictors of FIM Cognitive decline in the final model (area under the curve=0.75), while multiple health-related factors that can represent independent co-morbidities or possible consequences of injury were not.

CONCLUSION(S)

The strongest contributors to reported functional decline in cognitive activities later-in-life were related to acute characteristics of m-sTBI and experiencing post-traumatic seizures. Future studies are needed integrating functional with performance-based cognitive assessments to affirm conclusions and identify the timeline and trajectory of cognitive decline.

Long-term risk of cardiovascular disease after traumatic brain injury: screening and prevention

Traumatic brain injury (TBI) is highly prevalent among individuals participating in contact sports, military personnel, and in the general population. Although it is well known that brain injury can cause neurological and psychiatric complications, evidence from studies on individuals exposed to a single or repetitive brain injuries suggests an understudied association between TBI and the risk of developing chronic cardiovascular diseases and risk factors for cardiovascular disease. Several studies have shown that people without pre-existing comorbidities who sustain a TBI have a significantly higher risk of developing chronic cardiovascular disease, than people without TBI. Similar observations made in military and professional American-style football cohorts suggest causal pathways through which modifiable cardiovascular risk factors might mediate the relationship between brain injury and chronic neurological diseases. A better understanding of cardiovascular disease risk after TBI combined with a proactive, targeted screening programme might mitigate long-term morbidity and mortality in individuals with TBI, and improve their quality of life.

Modified Nutrition Risk in the Critically ill score and mortality in critically ill patients with traumatic brain injury

BACKGROUND

Understanding the relationship between nutrition risk at admission to the intensive care unit (ICU) and the prognosis of patients with traumatic brain injury (TBI) may aid early recognition of high-risk patients.

METHODS

We extracted data from the Medical Information Mart for Intensive Care III and the electronic ICU Collaborative Research Databases. Using modified Nutrition Risk in the Critically ill score (mNUTRIC) within the first 24 h of ICU admission, 5153 patients were divided into three groups: low (≤1, n = 1765), moderate (2-4, n = 2574), and high (≥5, n = 814). The primary outcome was 28-day in-hospital mortality, and the secondary outcomes were 7-day in-hospital mortality, length of ICU stay, and duration of mechanical ventilation.

RESULTS

During the median follow-up time of 6.69 days, 647 deaths occurred in total. After adjustment for potential confounding factors, setting the low mNUTRIC group as a reference, the risk of 28-day mortality was increased in the high and moderate mNUTRIC groups (hazard ratio [HR]high vs low [95% CI]: 4.21 [2.70-6.58] and 2.84 [1.95-4.14], respectively). Similarly, high and moderate mNUTRIC scores are linked to a higher risk of 7-day mortality (PTrend  < 0.001) and a longer duration of mechanical ventilation (PTrend  < 0.001). The effect of mNUTRIC on mortality varied by serum glucose level (PInteraction  = 0.01). Lastly, those whose mNUTRIC scores deteriorated within the first 3 days have a 1.46 times greater risk of dying compared with patients with improved mNUTRIC scores.

CONCLUSIONS

Nutrition risk screening by mNUTRIC score at the time of admission to the ICU may improve mortality prediction.

Associated Risk Factors and Impact in Clinical Outcomes of Multiorgan Failure in Patients with TBI

BACKGROUND

Individual extracerebral organ dysfunction is common after severe traumatic brain injury (TBI) and impacts outcomes. However, multiorgan failure (MOF) has received less attention in patients with isolated TBI. Our objective was to analyze the risk factors associated with the development of MOF and its impact in clinical outcomes in patients with TBI.

METHODS

This was an observational, prospective, multicenter study using data from a nationwide registry that currently includes 52 intensive care units (ICUs) in Spain (RETRAUCI). Isolated significant TBI was defined as Abbreviated Injury Scale (AIS) ≥ 3 in the head area with no AIS ≥ 3 in any other anatomical area. Multiorgan failure was defined using the Sequential-related Organ Failure Assessment as the alteration of two or more organs with a score of ≥ 3. We analyzed the contribution of MOF to crude and adjusted mortality (age and AIS head) by using logistic regression analysis. A multiple logistic regression analysis was performed to analyze the risk factors associated with the development of MOF in patients with isolated TBI.

RESULTS

A total of 9790 patients with trauma were admitted to the participating ICUs. Of them, 2964 (30.2%) had AIS head ≥ 3 and no AIS ≥ 3 in any other anatomical area, and these patients constituted the study cohort. Mean age was 54.7 (19.5) years, 76% of patients were men, and ground-level falls were the main mechanism of injury (49.1%). In-hospital mortality was 22.2%. Up to 185 patients with TBI (6.2%) developed MOF during their ICU stay. Crude and adjusted (age and AIS head) mortality was higher in patients who developed MOF (odds ratio 6.28 [95% confidence interval 4.58-8.60] and odds ratio 5.20 [95% confidence interval 3.53-7.45]), respectively. The logistic regression analysis showed that age, hemodynamic instability, the need of packed red blood cells concentrates in the initial 24 h, the severity of brain injury, and the need for invasive neuromonitoring were significantly associated with MOF development.

CONCLUSIONS

MOF occurred in 6.2% of patients with TBI admitted to the ICU and was associated with increased mortality. MOF was associated with age, hemodynamic instability, the need of packed red blood cells concentrates in the initial 24 h, the severity of brain injury, and the need for invasive neuromonitoring.

Effect of sacubitril/valsartan on brain natriuretic peptide level and prognosis of acute cerebral infarction

BACKGROUND AND PURPOSE

Previous studies demonstrated that elevated brain natriuretic peptide (BNP) level is associated with adverse clinical outcomes of acute cerebral infarction (ACI). Researchers hypothesized that BNP might be a potential neuroprotective factor against cerebral ischemia because of the antagonistic effect of the natriuretic peptide system on the renin-angiotensin system and regulation of cardiovascular homeostasis. However, whether decreasing the BNP level can improve the prognosis of ACI has not been studied yet. The main effect of sacubitril/valsartan is to enhance the natriuretic peptide system. We investigated whether the intervention of plasma BNP levels with sacubitril/valsartan could improve the prognosis of patients with ACI.

METHODS

In a randomized, controlled, parallel-group trial of patients with ACI within 48 hours of symptom onset and need for antihypertensive therapy, patients have randomized within 24 hours to sacubitril/valsartan 200mg once daily (the intervention group) or to conventional medical medication (the control group). The primary outcome was a change in plasma BNP levels before and after sacubitril/valsartan administration. The secondary outcomes included plasma levels of brain-derived neurotrophic factor (BDNF), Corin and neprilysin (NEP) before and after medication, the modified Rankin scale, and the National Institutes of Health Stroke Scale (at onset, at discharge, 30 days, and 90 days after discharge).

RESULTS

We evaluated 80 eligible patients admitted to the Stroke Center of Lianyungang Second People's Hospital between 1st May, 2021 and 31st June, 2022. Except for 28 patients excluded before randomization and 14 patients who did not meet the criteria or dropped out or lost to follow-up during the trial, the remaining 38 patients (intervention group: 17, control group: 21) had well-balanced baseline features. In this trial, we found that plasma BNP levels (P = 0.003) decreased and NEP levels (P = 0.006) increased in enrolled patients after treatment with sacubitril/valsartan. There were no differences in plasma BDNF and Corin levels between the two groups. Furthermore, no difference in functional prognosis was observed between the two groups (all P values>0.05).

CONCLUSIONS

Sacubitril/valsartan reduced endogenous plasma BNP levels in patients with ACI and did not affect their short-term prognosis.

Precision Concussion Management: Approaches to Quantifying Head Injury Severity and Recovery

Mitigating the substantial public health impact of concussion is a particularly difficult challenge. This is partly because concussion is a highly prevalent condition, and diagnosis is predominantly symptom-based. Much of contemporary concussion management relies on symptom interpretation and accurate reporting by patients. These types of reports may be influenced by a variety of factors for each individual, such as preexisting mental health conditions, headache disorders, and sleep conditions, among other factors. This can all be contributory to non-specific and potentially misleading clinical manifestations in the aftermath of a concussion. This review aimed to conduct an examination of the existing literature on emerging approaches for objectively evaluating potential concussion, as well as to highlight current gaps in understanding where further research is necessary. Objective assessments of visual and ocular motor concussion symptoms, specialized imaging techniques, and tissue-based concentrations of specific biomarkers have all shown promise for specifically characterizing diffuse brain injuries, and will be important to the future of concussion diagnosis and management. The consolidation of these approaches into a comprehensive examination progression will be the next horizon for increased precision in concussion diagnosis and treatment.

Psychiatric sequelae of traumatic brain injury - future directions in research

Despite growing appreciation that traumatic brain injury (TBI) is an important public health burden, our understanding of the psychiatric and behavioural consequences of TBI remains limited. These changes are particularly detrimental to a person's sense of self, their relationships and their participation in the wider community, and they continue to have devastating individual and cumulative effects long after TBI. This Review relates specifically to TBIs that confer objective clinical or biomarker evidence of structural brain injury; symptomatic head injuries without such evidence are outside the scope of this article. Common psychiatric, affective and behavioural sequelae of TBI and their proposed underlying mechanisms are outlined, along with a brief overview of current treatments. Suggestions for how scientists and clinicians can work together in the future to address the chasms in clinical care and knowledge are discussed in depth.

Long-term Multidomain Patterns of Change After Traumatic Brain Injury: A TRACK-TBI LONG Study

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) may be a chronic condition carrying risk of future sequelae; few prospective studies examine long-term postinjury outcomes. We examined the prevalence of functional, cognitive, and psychiatric change outcomes from 1 to 7 years postinjury.

METHODS

Transforming Research and Clinical Knowledge in TBI LONG (TRACK-TBI LONG) participants were prospectively enrolled within 24 hours of injury and followed up to 1 year postinjury; a subset participated in long-term follow-up from 2 to 7 years postinjury. Reliable change thresholds for the Brief Test of Adult Cognition by Telephone General Composite (cognition) and Brief Symptom Inventory (BSI)-18 (psychiatric) were derived from orthopedic trauma controls (OTCs). Multiple assessments were completed (postinjury baseline assessment and 2 or 3 visits 2-7 years postinjury) within a sample subset. Change was assessed for functional outcome (Glasgow Outcome Scale-Extended [GOSE]) and self-report/informant report of decline. Prevalence ratios for outcomes classified as stable, improved, and declined were reported individually and collectively. The Fisher exact test and log-binomial regression models examined factors associated with decline and improvement.

RESULTS

Of the sample (N = 1,264; mild TBI [mTBI], Glasgow Coma Scale [GCS] 13-15, n = 917; moderate-to-severe TBI [msTBI], GCS 3-12, n = 193; or OTC n = 154), "stable" was the most prevalent outcome. Functional outcome showed the highest rates of decline, regardless of TBI severity (mild = 29%; moderate/severe = 23%). When measures were collectively considered, rates of decline included mTBI (21%), msTBI (26%), and OTC (15%). Age and preinjury employment status were associated with functional decline (per 10 years; relative risk [RR] 1.16, 95% CI 1.07-1.25, p < 0.001; higher in retired/disabled/not working vs full-time/part-time; RR 1.81, 95% CI 1.33-2.45, respectively) in the mTBI group. Improvement in functional recovery 2-7 years postinjury was associated with higher BSI scores (per 5 points; RR 1.11, 95% CI 1.04-1.18, p = 0.002) and GOSE score of 5-7 (GOSE = 8 as reference; RR 2.64, 95% CI 1.75-3.97, p < 0.001). Higher BSI scores and identifying as Black (RR 2.28, 95% CI 1.59-3.25, p < 0.001) were associated with a greater likelihood of improved psychiatric symptoms in mTBI (RR 1.21, 95% CI 1.14-1.29, p < 0.001). A greater likelihood of cognitive improvement was observed among those with higher educational attainment in msTBI (per 4 years; RR 2.61, 95% CI 1.43-4.79, p = 0.002).

DISCUSSION

Function across domains at 1-year postinjury, a common recovery benchmark, undergoes change across the subsequent 6 years. Results support consideration of TBI as a chronic evolving condition and suggest continued monitoring, rehabilitation, and support is required to optimize long-term independence and quality of life.

Effect of Acupuncture on Recovery of Consciousness in Patients with Acute Traumatic Brain Injury: A Multi-Institutional Cohort Study

Traumatic brain injury (TBI) causes cognitive dysfunction and long-term impairments. This study aims to examine the effectiveness of acupuncture on the recovery of consciousness in TBI patients. This is a retrospective, multi-institutional cohort study. We enrolled patients with newly diagnosed TBI from 1 January 2007 to 3 August 2021, aged 20 years and older, from the Chang Gung Research Database (CGRD). The outcome was defined based on the difference between the first and last Glasgow Coma Scale (GCS). A total of 2163 TBI patients were analyzed, and 237 (11%) received acupuncture in the treatment period. Generally, the initial GCS was lower in the acupuncture users (11 vs. 14). For the results of our study, a higher proportion of acupuncture patients achieved significant improvement (GCS differences ≥ 3) compared to non-acupuncture users (46.0% vs. 22.4%, p-value < 0.001). The acupuncture users had a 2.11 times higher chance of achieving a significant improvement when considering all assessable covariates (adjusted odds ratio (aOR) 2, 11, 95% confidence interval [CI]: 1.31-3.40; p-value = 0.002). Using 1:1 propensity score matching (PSM), the acupuncture users still had better outcomes than the non-acupuncture users (45.3% vs. 32.9%, p-value = 0.020). In conclusion, this study suggests that acupuncture treatment may be beneficial for TBI patients.

Vγ1 and Vγ4 gamma-delta T cells play opposing roles in the immunopathology of traumatic brain injury in males

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality. The innate and adaptive immune responses play an important role in the pathogenesis of TBI. Gamma-delta (γδ) T cells have been shown to affect brain immunopathology in multiple different conditions, however, their role in acute and chronic TBI is largely unknown. Here, we show that γδ T cells affect the pathophysiology of TBI as early as one day and up to one year following injury in a mouse model. TCRδ^-/- mice are characterized by reduced inflammation in acute TBI and improved neurocognitive functions in chronic TBI. We find that the Vγ1 and Vγ4 γδ T cell subsets play opposing roles in TBI. Vγ4 γδ T cells infiltrate the brain and secrete IFN-γ and IL-17 that activate microglia and induce neuroinflammation. Vγ1 γδ T cells, however, secrete TGF-β that maintains microglial homeostasis and dampens TBI upon infiltrating the brain. These findings provide new insights on the role of different γδ T cell subsets after brain injury and lay down the principles for the development of targeted γδ T-cell-based therapy for TBI.

Brain Injury: How Dietary Patterns Impact Long-Term Outcomes

Purpose of Review

Individuals with a history of traumatic brain injury (TBI) are at a much greater risk for developing cardiovascular disease (CVD) compared to the general population. This review discusses dietary patterns as a means of addressing modifiable risk factors following TBI exposure. Evidence-based resources for practicing Physiatrists and Brain Injury Medicine specialists pertaining to nutrition education and counseling are also provided.

Recent Findings

We examined Mediterranean, Dietary Approaches to Stop Hypertension, plant-based, ketogenic, and intermittent fasting dietary patterns through publications of clinical trials and systematic reviews. While many reviews had significant positive findings, some were limited by generalizability.

Summary

While there is extensive literature on the immediate nutrition goals in the inpatient setting following an acute TBI exposure, there is limited literature discussing the nature of diet and nutrition in the post-acute setting. Fortunately, most individuals with TBI exposure survive their initial injury and continue into the recovery phase. The scientific literature supports increased morbidity and mortality with chronic TBI exposure compared to matched counterparts, most notably with CVD. A diet rich in fiber and nutrients but limited in added sugars, saturated fats, and excess calories would likely have the greatest cardiovascular and related neurologic protection. Future studies are needed to assess the specific impact of dietary interventions in the chronic phase of brain injury recovery.

Associations of Military-Related Traumatic Brain Injury With New-Onset Mental Health Conditions and Suicide Risk

Importance

Research to identify the direct and indirect associations of military-related traumatic brain injury (TBI) with suicide has been complicated by a range of data-related challenges.

Objective

To identify differences in rates of new-onset mental health conditions (ie, anxiety, mood, posttraumatic stress, adjustment, alcohol use, and substance use disorders) among soldiers with and without a history of military-related TBI and to explore the direct and indirect (through new-onset mental health disorders) associations of TBI with suicide.

Design, Setting, and Participants

This retrospective cohort study used data from the Substance Use and Psychological Injury Combat Study (SUPIC) database. Demographic, military, and health data from the Department of Defense within SUPIC were compiled and linked with National Death Index records to identify deaths by suicide. Participants included US Army soldiers who returned from an Afghanistan or Iraq deployment. Data were analyzed from September to December 2022.

Exposures

Military-related TBI.

Main Outcomes and Measures

The outcome of interest was suicide. Secondary outcomes were incidence of new-onset mental health conditions. Mediation analyses consisted of accelerated failure time (AFT) models in conjunction with the product of coefficients method. The 6 new-onset mental health diagnosis categories and the 2 or more categories variable were each considered separately as potential mediators; therefore, a total of 14 models plus the overall AFT model estimating the total effect associated with TBI in suicide risk were fit.

Results

The study included 860 892 soldiers (320 539 soldiers [37.2%] aged 18-24 at end of index deployment; 766 454 [89.0%] male), with 108 785 soldiers (12.6%) with at least 1 documented TBI on their military health record. Larger increases in mental health diagnoses were observed for all conditions from before to after documented TBI, compared with the matched dates for those without a history of TBI, with increases observed for mood (67.7% vs 37.5%) and substance use (100% vs 14.5%). Time-to-suicide direct effect estimates for soldiers with a history of TBI were similar across mediators. For example, considering new-onset adjustment disorders, time-to-suicide was 16.7% faster (deceleration factor, 0.833; 95% CI, 0.756-0.912) than for soldiers without a history of TBI. Indirect effect estimates of associations with TBI were substantial and varied across mediators. The largest indirect effect estimate was observed through the association with new-onset substance use disorder, with a time to suicide 63.8% faster (deceleration factor, 0.372; 95% CI, 0.322-0.433) for soldiers with a history of TBI.

Conclusions and Relevance

In this longitudinal cohort study of soldiers, rates of new-onset mental health conditions were higher among individuals with a history of TBI compared with those without. Moreover, risk for suicide was both directly and indirectly associated with history of TBI. These findings suggest that increased efforts are needed to conceptualize the accumulation of risk associated with multiple military-related exposures and identify evidence-based interventions that address mechanisms associated with frequently co-occurring conditions.