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.

Phenotyping Depression After Mild Traumatic Brain Injury: Evaluating the Impact of Multiple Injury, Gender, and Injury Context

The chronic mental health consequences of mild traumatic brain injury (TBI) are a leading cause of disability. This is surprising given the expectation of significant recovery after mild TBI, which suggests that other injury-related factors may contribute to long-term adverse outcomes. The objective of this study was to determine how number of prior injuries, gender, and environment/context of injury may contribute to depressive symptoms after mild TBI among deployed United States service members and veterans (SMVs). Data from the Long-term Impact of Military-Relevant Brain Injury Consortium Prospective Longitudinal Study was used to assess TBI injury characteristics and depression scores previously measured on the Patient Health Questionnaire-9 (PHQ-9) among a sample of 1456 deployed SMVs. Clinical diagnosis of mild TBI was defined via a multi-step process centered on a structured face-to-face interview. Logistical and linear regressions stratified by gender and environment of injury were used to model depressive symptoms controlling for sociodemographic and combat deployment covariates. Relative to controls with no history of mild TBI (n = 280), the odds ratios (OR) for moderate/severe depression (PHQ-9 ≥ 10) were higher for SMVs with one mild TBI (n = 358) OR: 1.62 (95% confidence interval [CI] 1.09-2.40, p = 0.016) and two or more mild TBIs (n = 818) OR: 1.84 (95% CI 1.31-2.59, p < 0.001). Risk differences across groups were assessed in stratified linear models, which found that depression symptoms were elevated in those with a history of multiple mild TBIs compared with those who had a single mild TBI (p < 0.001). Combat deployment-related injuries were also associated with higher depression scores than injuries occurring in non-combat or civilian settings (p < 0.001). Increased rates of depression after mild TBI persisted in the absence of post-traumatic stress disorder. Both men and women SMVs separately exhibited significantly increased depressive symptom scores if they had had combat-related mild TBI. These results suggest that contextual information, gender, and prior injury history may influence long-term mental health outcomes among SMVs with mild TBI exposure.

Mild traumatic brain injury, PTSD symptom severity, and behavioral dyscontrol: a LIMBIC-CENC study

Background

Behavioral dyscontrol occurs commonly in the general population and in United States service members and Veterans (SM/V). This condition merits special attention in SM/V, particularly in the aftermath of deployments. Military deployments frequently give rise to posttraumatic stress disorder (PTSD) and deployment-related mild TBI traumatic brain injury (TBI), potentially leading to manifestations of behavioral dyscontrol.

Objective

Examine associations among PTSD symptom severity, deployment-related mild traumatic brain injury, and behavioral dyscontrol among SM/V.

Design

Secondary cross-sectional data analysis from the Long-Term Impact of Military-Relevant Brain Injury Consortium - Chronic Effects of Neurotrauma Consortium prospective longitudinal study among SM/V (N = 1,808).

Methods

Univariable and multivariable linear regression models assessed the association and interaction effects between PTSD symptom severity, as assessed by the PTSD Checklist for the Diagnostic and Statistical Manual, 5th edition (PCL-5), and deployment-related mild TBI on behavioral dyscontrol, adjusting for demographics, pain, social support, resilience, and general self-efficacy.

Results

Among the 1,808 individuals in our sample, PTSD symptom severity (B = 0.23, 95% CI: 0.22, 0.25, p < 0.001) and deployment-related mild TBI (B = 3.27, 95% CI: 2.63, 3.90, p < 0.001) were significantly associated with behavioral dyscontrol in univariable analysis. Interaction effects were significant between PTSD symptom severity and deployment mild TBI (B = -0.03, 95% CI: -0.06, -0.01, p = 0.029) in multivariable analysis, indicating that the effect of mild TBI on behavioral dyscontrol is no longer significant among those with a PCL-5 score > 22.96.

Conclusion

Results indicated an association between PTSD symptom severity, deployment-related mild TBI, and behavioral dyscontrol among SM/V. Notably, the effect of deployment-related mild TBI was pronounced for individuals with lower PTSD symptom severity. Higher social support scores were associated with lower dyscontrol, emphasizing the potential for social support to be a protective factor. General self-efficacy was also associated with reduced behavioral dyscontrol.

Smaller total and subregional cerebellar volumes in posttraumatic stress disorder: a mega-analysis by the ENIGMA-PGC PTSD workgroup

Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p-FDR < 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.

Microstructural Organization of Distributed White Matter Associated With Fine Motor Control in US Service Members With Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common form of brain injury. While most individuals recover from mTBI, roughly 20% experience persistent symptoms, potentially including reduced fine motor control. We investigate relationships between regional white matter organization and subcortical volumes associated with performance on the Grooved Pegboard (GPB) test in a large cohort of military Service Members and Veterans (SM&Vs) with and without a history of mTBI(s). Participants were enrolled in the Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium. SM&Vs with a history of mTBI(s) (n = 847) and without mTBI (n = 190) underwent magnetic resonance imaging and the GPB test. We first examined between-group differences in GPB completion time. We then investigated associations between GPB performance and regional structural imaging measures (tractwise diffusivity, subcortical volumes, and cortical thickness) in SM&Vs with a history of mTBI(s). Lastly, we explored whether mTBI history moderated associations between imaging measures and GPB performance. SM&Vs with mTBI(s) performed worse than those without mTBI(s) on the non-dominant hand GPB test at a trend level (p < 0.1). Higher fractional anisotropy (FA) of tracts including the posterior corona radiata, superior longitudinal fasciculus, and uncinate fasciculus were associated with better GPB performance in the dominant hand in SM&Vs with mTBI(s). These findings support that the organization of several white matter bundles are associated with fine motor performance in SM&Vs. We did not observe that mTBI history moderated associations between regional FA and GPB test completion time, suggesting that chronic mTBI may not significantly influence fine motor control.

Associations of Chronic Pain With Psychosocial Outcomes After Traumatic Brain Injury: A NIDILRR and VA TBI Model Systems Collaborative Project

OBJECTIVE

To examine the differences in participation, life satisfaction, and psychosocial outcomes among individuals with traumatic brain injury (TBI) endorsing current, past, or no chronic pain.

SETTING

Community.

PARTICIPANTS

Three thousand eight hundred four TBI Model Systems participants 1 to 30 years of age postinjury classified into 1 of 3 groups based on their pain experience: current pain, past pain, no pain completed a Pain Survey at their usual follow-up appointment which on average was approximately 8 years postinjury.

DESIGN

Multisite, cross-sectional observational cohort study.

MAIN OUTCOME MEASURES

Sociodemographic and injury characteristics and psychosocial outcomes (ie, satisfaction with life, depression, anxiety, posttraumatic stress disorder [PTSD], sleep quality, community participation).

RESULTS

Persons with current chronic pain demonstrated higher scores on measures of PTSD, anxiety, and depression, and the lower scores on measures of sleep quality, community participation and satisfaction with life. Those with resolved past pain had mean scores for these outcomes that were all between the current and no chronic pain groups, but always closest to the no pain group. After adjusting for sociodemographic and function in multivariate analysis, having current chronic pain was associated with more negative psychosocial outcomes. The largest effect sizes (ES; in absolute value) were observed for the PTSD, depression, anxiety, and sleep quality measures (ES = 0.52-0.81) when comparing current pain to past or no pain, smaller ES were observed for life satisfaction (ES = 0.22-0.37) and out and about participation (ES = 0.16-0.18). When comparing past and no pain groups, adjusted ES were generally small for life satisfaction, PTSD, depression, anxiety, and sleep quality (ES = 0.10-0.23) and minimal for participation outcomes (ES = 0.02-0.06).

CONCLUSIONS

Chronic pain is prevalent among individuals with TBI and is associated with poorer psychosocial outcomes, especially for PTSD, depression, anxiety, and sleep disturbance. The results from this study highlight the presence of modifiable comorbidities among those with chronic pain and TBI. Persons who experience persistent pain following TBI may be at greater risk for worse psychosocial outcomes.

Characterizing Extreme Phenotypes for Pain Interference in Persons With Chronic Pain Following Traumatic Brain Injury: A NIDILRR and VA TBI Model Systems Collaborative Project

OBJECTIVE

To define and characterize extreme phenotypes based on pain interference for persons with chronic pain following traumatic brain injury (TBI).

SETTING

Eighteen Traumatic Brain Injury Model System (TBIMS) Centers.

PARTICIPANTS

A total of 1762 TBIMS participants 1 to 30 years post-injury reporting chronic pain at their most recent follow-up interview.

PRIMARY MEASURES

The Brief Pain Inventory (BPI) interference scale, sociodemographic, injury, functional outcome, pain, and treatment characteristics.

RESULTS

Participants were predominantly male (73%), White (75%), middle-aged (mean 46 years), and who were injured in motor vehicle accidents (53%) or falls (20%). Extreme phenotypes were identified based on upper and lower 25th percentiles to create low-interference ( n = 441) and high-interference ( n = 431) extreme phenotypes. Bivariate comparisons found several sociodemographic, injury, function, pain, and treatment differences between extreme phenotype groups, including significant differences ( P < .001) on all measures of concurrent function with those in the low-interference extreme phenotype experiencing better function than those in the high-interference extreme phenotype. Lasso regression combined with logistic regression identified multivariable predictors of low- versus high-interference extreme phenotypes. Reductions in the odds of low- versus high-interference phenotypes were significantly associated with higher pain intensity (odds ratio [OR] = 0.33), having neuropathic pain (OR = 0.40), migraine headache (OR = 0.41), leg/feet pain (OR = 0.34), or hip pain (OR = 0.46), and more pain catastrophizing (OR = 0.81).

CONCLUSION

Results suggest that for those who experience current chronic pain, there is high variability in the experience and impact of pain. Future research is needed to better understand how pain experience impacts individuals with chronic pain and TBI given that pain characteristics were the primary distinguishing factors between phenotypes. The use of extreme phenotypes for pain interference may be useful to better stratify samples to determine efficacy of pain treatment for individuals with TBI.

Relationship Between Extreme Pain Phenotypes and Psychosocial Outcomes in Persons With Chronic Pain Following Traumatic Brain Injury: A NIDILRR and VA TBI Model Systems Collaborative Project

OBJECTIVE

To examine the relationship between extreme pain phenotypes (interference and improvement) and psychosocial outcomes among those with chronic pain after traumatic brain injury (TBI).

SETTING

Community.

PARTICIPANTS

In total, 1762 TBI Model Systems (TBIMS) participants 1 to 30 years postinjury reporting chronic pain.

DESIGN

Multisite, cross-sectional, observational cohort study.

PRIMARY MEASURES

Life satisfaction, posttraumatic stress, depression and anxiety symptoms, sleep and participation, the Brief Pain Inventory (BPI) interference scale, and the Patient's Global Impression of Change (PGIC).

RESULTS

Persons in the extreme high interference phenotype (vs extreme low interference phenotype) and/or extreme no change phenotype (vs extreme improvement phenotype) had poorer psychosocial outcomes, with extreme pain interference phenotypes having a larger effect on outcomes than extreme perceived improvement phenotypes. After controlling for covariates, large effect sizes (ES) related to pain interference were observed for posttraumatic stress symptoms (ES = -1.14), sleep quality (ES = -1.10), depression (ES = -1.08), anxiety (ES = -0.82), and life satisfaction (ES = 0.76); effect sizes for participation outcomes, although significant, were relatively small (ES = 0.21-0.36). Effect sizes related to perceived improvement were small for life satisfaction (ES = 0.20) and participation (ES = 0.16-0.21) outcomes. Pain intensity was identified as a meaningful confounding factor of the relationships between extreme phenotypes and posttraumatic stress, depression, anxiety, and sleep quality.

CONCLUSIONS

Examination of extreme phenotypes provides important insights into the experience of individuals living with chronic pain and TBI. Results suggest that the relationships among a variety of characteristics of the person, their experience with pain, and treatment of pain are complex. Further research is needed to better understand these complex relationships and how differences in pain interference and perceived improvement from treatment can assist in assessment and treatment of chronic pain after TBI.

What Are the Predictors for and Psychosocial Correlates of Chronic Headache After Moderate to Severe Traumatic Brain Injury?

OBJECTIVE

Although headache (HA) is a common sequela of traumatic brain injury (TBI), early predictors of chronic HA after moderate to severe TBI are not well established, and the relationship chronic HA has with psychosocial functioning is understudied. Thus, we sought to (1) determine demographic and injury predictors of chronic HA 1 or more years after moderate to severe TBI and (2) examine associations between chronic HA and psychosocial outcomes.

SETTING

Community.

PARTICIPANTS

Participants in the TBI Model System (TBIMS) with moderate to severe TBI who consented for additional chronic pain questionnaires at the time of TBIMS follow-up.

DESIGN

Multisite, observational cohort study using LASSO (least absolute shrinkage and selection operator) regression for prediction modeling and independent t tests for psychosocial associations.

MAIN OUTCOME MEASURES

Chronic HA after TBI at year 1 or 2 postinjury and more remotely (5 or more years).

RESULTS

The LASSO model for chronic HA at 1 to 2 years achieved acceptable predictability (cross-validated area under the curve [AUC] = 0.70). At 5 or more years, predictability was nearly acceptable (cross-validated AUC = 0.68), but much more complex, with more than twice as many variables contributing. Injury characteristics had stronger predictive value at postinjury years 1 to 2 versus 5 or more years, especially sustained intracranial pressure elevation (odds ratio [OR] = 3.8) and skull fragments on head computed tomography (CT) (OR = 2.5). Additional TBI(s) was a risk factor at both time frames, as were multiple socioeconomic characteristics, including lower education level, younger age, female gender, and Black race. Lower education level was a particularly strong predictor at 5 or more years (OR up to 3.5). Emotional and participation outcomes were broadly poorer among persons with chronic HA after moderate to severe TBI.

CONCLUSIONS

Among people with moderate to severe TBI, chronic HA is associated with significant psychosocial burden. The identified risk factors will enable targeted clinical screening and monitoring strategies to enhance clinical care pathways that could lead to better outcomes. They may also be useful as stratification or covariates in future clinical trial research on treatments.

Characterization and Treatment of Chronic Pain After Traumatic Brain Injury-Comparison of Characteristics Between Individuals With Current Pain, Past Pain, and No Pain: A NIDILRR and VA TBI Model Systems Collaborative Project

OBJECTIVE

To estimate the prevalence of chronic pain after traumatic brain injury (TBI) and identify characteristics that differ from those without chronic pain.

SETTING

Community.

PARTICIPANTS

A total of 3804 TBI Model Systems (TBIMS) participants who completed the Pain Survey at TBIMS follow-up.

DESIGN

A multisite, cross-sectional observational cohort study.

MAIN OUTCOME MEASURES

Functional outcomes, pain experience, and treatment.

RESULTS

46% reported current chronic pain, 14% reported past (post-injury) chronic pain, and 40% reported no chronic pain. Bivariate differences in sociodemographic and injury characteristics between the 3 pain groups were generally small in effect size, reflecting little clinical difference. However, medium effect sizes were seen for all functional outcomes, such that individuals with current chronic pain had worse functional outcomes compared with individuals in the past pain or no pain groups. Treatment utilization rates were higher for individuals with current chronic pain compared with past pain, with medical treatments being most frequently utilized. Individuals with past pain perceived more improvement with treatment than did those with current chronic pain as represented by a large effect size.

CONCLUSIONS

Chronic pain affects approximately 60% of those living with TBI. The implications of chronic pain for functional outcomes support inclusion of pain metrics in prognostic models and observational studies in this population. Future research is needed to proactively identify those at risk for the development of chronic pain and determine the efficacy and access to pain treatment.

Characterizing Extreme Phenotypes for Perceived Improvement From Treatment in Persons With Chronic Pain Following Traumatic Brain Injury: A NIDILRR and VA TBI Model Systems Collaborative Project

OBJECTIVE

To define and characterize extreme phenotypes based on perceived improvement in pain for persons with chronic pain following traumatic brain injury (TBI).

SETTING

Eighteen Traumatic Brain Injury Model System (TBIMS) Centers.

PARTICIPANTS

A total of 1762 TBIMS participants 1 to 30 years post-injury reporting chronic pain at their most recent follow-up interview.

PRIMARY MEASURES

The Patient's Global Impression of Change (PGIC) related to pain treatment. Sociodemographic, injury, functional outcome, pain, and pain treatment characteristics.

RESULTS

Participants were mostly male (73%), White (75%), middle-aged (mean 46 years), injured in motor vehicle accidents (53%), or falls (20%). Extreme phenotypes were created for an extreme improvement phenotype ( n = 512, 29.8%) defined as "moderately better" or above on the PGIC and an extreme no-change group ( n = 290, 16.9%) defined as no change or worse. Least absolute shrinkage and selection operator (LASSO) regression combined with logistic regression identified multivariable predictors of improvement versus no-change extreme phenotypes. Higher odds of extreme improvement phenotype were significantly associated with being female (odds ratio [OR] = 1.85), married versus single (OR = 2.02), better motor function (OR = 1.03), lower pain intensity (OR = 0.78), and less frequent pain, especially chest pain (OR = 0.36). Several pain treatments were associated with higher odds of being in the extreme improvement versus no-change phenotypes including pain medication (OR = 1.85), physical therapy (OR = 1.51), yoga (OR = 1.61), home exercise program (OR = 1.07), and massage (OR = 1.69).

CONCLUSION

Investigation of extreme phenotypes based on perceived improvement with pain treatment highlights the ability to identify characteristics of individuals based on pain treatment responsiveness. A better understanding of the biopsychosocial characteristics of those who respond and do not respond to pain treatments received may help inform better surveillance, monitoring, and treatment. With further research, the identification of risk factors (such as pain intensity and frequency) for treatment response/nonresponse may provide indicators to prompt changes in care for individuals with chronic pain after TBI.

Subcortical functional connectivity and its association with walking performance following deployment related mild TBI

Introduction

The relation between traumatic brain injury (TBI), its acute and chronic symptoms, and the potential for remote neurodegenerative disease is a priority for military research. Structural and functional connectivity (FC) of the basal ganglia, involved in motor tasks such as walking, are altered in some samples of Service Members and Veterans with TBI, but any behavioral implications are unclear and could further depend on the context in which the TBI occurred.

Methods

In this study, FC from caudate and pallidum seeds was measured in Service Members and Veterans with a history of mild TBI that occurred during combat deployment, Service Members and Veterans whose mild TBI occurred outside of deployment, and Service Members and Veterans who had no lifetime history of TBI.

Results

FC patterns differed for the two contextual types of mild TBI. Service Members and Veterans with deployment-related mild TBI demonstrated increased FC between the right caudate and lateral occipital regions relative to both the non-deployment mild TBI and TBI-negative groups. When evaluating the association between FC from the caudate and gait, the non-deployment mild TBI group showed a significant positive relationship between walking time and FC with the frontal pole, implicated in navigational planning, whereas the deployment-related mild TBI group trended towards a greater negative association between walking time and FC within the occipital lobes, associated with visuo-spatial processing during navigation.

Discussion

These findings have implications for elucidating subtle motor disruption in Service Members and Veterans with deployment-related mild TBI. Possible implications for future walking performance are discussed.

Relation of Aerobic Activity to Cognition and Well-being in Chronic Mild Traumatic Brain Injury: A LIMBIC-CENC Study

INTRODUCTION

Because chronic difficulties with cognition and well-being are common after mild traumatic brain injury (mTBI) and aerobic physical activity and exercise (PAE) is a potential treatment and mitigation strategy, we sought to determine their relationship in a large sample with remote mTBI.

MATERIALS AND METHODS

The Long-Term Impact of Military-Relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium prospective longitudinal study is a national multicenter observational study of combat-exposed service members and veterans. Study participants with positive mTBI histories (n = 1,087) were classified as "inactive" (23%), "insufficiently active" (46%), "active" (19%), or "highly active" (13%) based on the aerobic PAE level. The design was a cross-sectional analysis with multivariable regression. PAE was reported on the Behavioral Risk Factor Surveillance System. Preselected primary outcomes were seven well-validated cognitive performance tests of executive function, learning, and memory: The California Verbal Learning Test-Second Edition Long-Delay Free Recall and Total Recall, Brief Visuospatial Memory Test-Revised Total Recall, Trail-Making Test-Part B, and NIH Toolbox for the Assessment of Neurological Behavior and Function Cognition Battery Picture Sequence Memory, Flanker, and Dimensional Change Card Sort tests. Preselected secondary outcomes were standardized self-report questionnaires of cognitive functioning, life satisfaction, and well-being.

RESULTS

Across the aerobic activity groups, cognitive performance tests were not significantly different. Life satisfaction and overall health status scores were higher for those engaging in regular aerobic activity. Exploratory analyses also showed better working memory and verbal fluency with higher aerobic activity levels.

CONCLUSIONS

An association between the aerobic activity level and the preselected primary cognitive performance outcome was not demonstrated using this study sample and methods. However, higher aerobic activity levels were associated with better subjective well-being. This supports a clinical recommendation for regular aerobic exercise among persons with chronic or remote mTBI. Future longitudinal analyses of the exercise-cognition relationship in chronic mTBI populations are recommended.

Headache among combat-exposed veterans and service members and its relation to mild traumatic brain injury history and other factors: a LIMBIC-CENC study

Background

Headache (HA) is a common persistent complaint following mild traumatic brain injury (mTBI), but the association with remote mTBI is not well established, and risk factors are understudied.

Objective

Determine the relationship of mTBI history and other factors with HA prevalence and impact among combat-exposed current and former service members (SMs).

Design

Secondary cross-sectional data analysis from the Long-Term Impact of Military-Relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium prospective longitudinal study.

Methods

We examined the association of lifetime mTBI history, demographic, military, medical and psychosocial factors with (1) HA prevalence ("lately, have you experienced headaches?") using logistic regression and (2) HA burden via the Headache Impact Test-6 (HIT-6) using linear regression. Each lifetime mTBI was categorized by mechanism (blast-related or not) and setting (combat deployed or not). Participants with non-credible symptom reporting were excluded, leaving N = 1,685 of whom 81% had positive mTBI histories.

Results

At a median 10 years since last mTBI, mTBI positive participants had higher HA prevalence (69% overall, 78% if 3 or more mTBIs) and greater HA burden (67% substantial/severe impact) than non-TBI controls (46% prevalence, 54% substantial/severe impact). In covariate-adjusted analysis, HA prevalence was higher with greater number of blast-related mTBIs (OR 1.81; 95% CI 1.48, 2.23), non-blast mTBIs while deployed (OR 1.42; 95% CI 1.14, 1.79), or non-blast mTBIs when not deployed (OR 1.23; 95% CI 1.02, 1.49). HA impact was only higher with blast-related mTBIs. Female identity, younger age, PTSD symptoms, and subjective sleep quality showed effects in both prevalence and impact models, with the largest mean HIT-6 elevation for PTSD symptoms. Additionally, combat deployment duration and depression symptoms were factors for HA prevalence, and Black race and Hispanic/Latino ethnicity were factors for HA impact. In sensitivity analyses, time since last mTBI and early HA onset were both non-significant.

Conclusion

The prevalence of HA symptoms among formerly combat-deployed veterans and SMs is higher with more lifetime mTBIs regardless of how remote. Blast-related mTBI raises the risk the most and is uniquely associated with elevated HA burden. Other demographic and potentially modifiable risk factors were identified that may inform clinical care.

Sensory functions and their relation to balance metrics: a secondary analysis of the LIMBIC-CENC multicenter cohort

Introduction

Among patients with traumatic brain injury (TBI), balance problems often persist alongside hearing and vision impairments that lead to poorer outcomes of functional independence. As such, the ability to regain premorbid independent gait may be dictated by the level of sensory acuity or processing decrements that are shown following TBI assessment. This study explores the relationships between standardized sensory acuity and processing outcomes to postural balance and gait speed.

Methods

Secondary analysis was performed on the Long-Term Impact of Military- Relevant Brain Injury Consortium Chronic Effects of Neurotrauma Consortium LIMBIC (CENC) data set. Separate regression analyses were carried out for each of the balance assessments (via Computerized Dynamic Posturography, CDP) and walking speed.

Discussion

TBI frequency was significantly related to the majority of single CDP outcomes (i.e., Conditions 2-6), while various sensory processing outcomes had task-specific influences. Hearing impairments and auditory processing decrements presented with lower CDP scores (CDP Conditions 3,5,6, and 1-3 respectively), whereas greater visual processing scores were associated with better CDP scores for Conditions 2,5, and 6. In sum, patients with TBI had similar scores on static balance tests compared to non-TBI, but when the balance task got more difficult patients with TBI scored worse on the balance tests. Additionally, stronger associations with sensory processing than sensory acuity measures may indicate that patients with TBI have increased fall risk.

The American Congress of Rehabilitation Medicine Diagnostic Criteria for Mild Traumatic Brain Injury

OBJECTIVE

To develop new diagnostic criteria for mild traumatic brain injury (TBI) that are appropriate for use across the lifespan and in sports, civilian trauma, and military settings.

DESIGN

Rapid evidence reviews on 12 clinical questions and Delphi method for expert consensus.

PARTICIPANTS

The Mild Traumatic Brain Injury Task Force of the American Congress of Rehabilitation Medicine Brain Injury Special Interest Group convened a Working Group of 17 members and an external interdisciplinary expert panel of 32 clinician-scientists. Public stakeholder feedback was analyzed from 68 individuals and 23 organizations.

RESULTS

The first two Delphi votes asked the expert panel to rate their agreement with both the diagnostic criteria for mild TBI and the supporting evidence statements. In the first round, 10 of 12 evidence statements reached consensus agreement. Revised evidence statements underwent a second round of expert panel voting, where consensus was achieved for all. For the diagnostic criteria, the final agreement rate, after the third vote, was 90.7%. Public stakeholder feedback was incorporated into the diagnostic criteria revision prior to the third expert panel vote. A terminology question was added to the third round of Delphi voting, where 30 of 32 (93.8%) expert panel members agreed that 'the diagnostic label 'concussion' may be used interchangeably with 'mild TBI' when neuroimaging is normal or not clinically indicated.'

CONCLUSIONS

New diagnostic criteria for mild TBI were developed through an evidence review and expert consensus process. Having unified diagnostic criteria for mild TBI can improve the quality and consistency of mild TBI research and clinical care.

Distal and Proximal Predictors of Rehospitalization Over 10 Years Among Survivors of TBI: A National Institute on Disability, Independent Living, and Rehabilitation Research Traumatic Brain Injury Model Systems Study

OBJECTIVE

To describe the rates and causes of rehospitalization over a 10-year period following a moderate-severe traumatic brain injury (TBI) utilizing the Healthcare Cost and Utilization Project (HCUP) diagnostic coding scheme.

SETTING

TBI Model Systems centers.

PARTICIPANTS

Individuals 16 years and older with a primary diagnosis of TBI.

DESIGN

Prospective cohort study.

MAIN MEASURES

Rehospitalization (and reason for rehospitalization) as reported by participants or their proxies during follow-up telephone interviews at 1, 2, 5, and 10 years postinjury.

RESULTS

The greatest number of rehospitalizations occurred in the first year postinjury (23.4% of the sample), and the rates of rehospitalization remained stable (21.1%-20.9%) at 2 and 5 years postinjury and then decreased slightly (18.6%) at 10 years postinjury. Reasons for rehospitalization varied over time, but seizure was the most common reason at 1, 2, and 5 years postinjury. Other common reasons were related to need for procedures (eg, craniotomy or craniectomy) or medical comorbid conditions (eg, diseases of the heart, bacterial infections, or fractures). Multivariable logistic regression models showed that Functional Independence Measure (FIM) Motor score at time of discharge from inpatient rehabilitation was consistently associated with rehospitalization at all time points. Other factors associated with future rehospitalization over time included a history of rehospitalization, presence of seizures, need for craniotomy/craniectomy during acute hospitalization, as well as older age and greater physical and mental health comorbidities.

CONCLUSION

Using diagnostic codes to characterize reasons for rehospitalization may facilitate identification of baseline (eg, FIM Motor score or craniotomy/craniectomy) and proximal (eg, seizures or prior rehospitalization) factors that are associated with rehospitalization. Information about reasons for rehospitalization can aid healthcare system planning. By identifying those recovering from TBI at a higher risk for rehospitalization, providing closer monitoring may help decrease the healthcare burden by preventing rehospitalization.

Impact of Posttraumatic Amnesia Duration on Traumatic Brain Injury (TBI) First Year Hospital Costs: A Veterans Affairs TBI Model Systems Study

OBJECTIVE

To examine the association between severity of traumatic brain injury (TBI) as measured by duration of post-traumatic amnesia (PTA) and first year hospitalization costs for service members and veterans (SMVs) treated for TBI at Polytrauma Rehabilitation Centers (PRCs) within the Veterans Health Administration (VHA).

DESIGN

Multivariable models of merged datasets from the VA TBI Model Systems (VA-TBIMS) national database containing TBI clinical characterization including PTA with VHA hospital cost data.

SETTING

Five VA PRCs.

PARTICIPANTS

VA-TBIMS participants with known PTA who received inpatient rehabilitation within 1 year of their TBI at any of 5 PRCs between 2010-2020.

INTERVENTIONS

N/A MAIN OUTCOME MEASURES: Total, acute care, rehabilitation, intensive care unit (ICU), and surgery costs across all VA hospitals.

RESULTS

A total of 717 SMVs (mean age 36.9 years, 94.1% male, 76.8% non-Hispanic White, 7.8% active duty) met inclusion criteria for the unadjusted analyses. Unadjusted mean total hospital costs in the first-year post TBI were approximately $201,214 higher for those with PTA duration ≥24 hours ($351,157) than PTA <24 hours ($149,943). In adjusted models (n=583), each additional day of PTA duration incrementally increased total ($1453), rehabilitation ($1324), ICU ($78) and surgery ($39) costs. Other significant covariates included age, acute care length of stay, Disability Rating Scale on rehabilitation admission, penetrating violent cause of injury, and drug abuse.

CONCLUSIONS

This study demonstrates that PTA as a quantitative measure of TBI severity significantly impacts first-year hospitalization costs of SMVs treated at PRCs. Each additional day of PTA was associated with higher total, rehabilitation, ICU, and surgery costs. Mean first year hospital costs were also found to exceed the highest budget allocation to VHA facilities for a veteran treated at a PRC. These findings have possible implications for hospital care provision for those receiving inpatient rehabilitation in VHA settings.

Bridging Big Data: Procedures for Combining Non-equivalent Cognitive Measures from the ENIGMA Consortium

Investigators in neuroscience have turned to Big Data to address replication and reliability issues by increasing sample sizes, statistical power, and representativeness of data. These efforts unveil new questions about integrating data arising from distinct sources and instruments. We focus on the most frequently assessed cognitive domain - memory testing - and demonstrate a process for reliable data harmonization across three common measures. We aggregated global raw data from 53 studies totaling N = 10,505 individuals. A mega-analysis was conducted using empirical bayes harmonization to remove site effects, followed by linear models adjusting for common covariates. A continuous item response theory (IRT) model estimated each individual's latent verbal learning ability while accounting for item difficulties. Harmonization significantly reduced inter-site variance while preserving covariate effects, and our conversion tool is freely available online. This demonstrates that large-scale data sharing and harmonization initiatives can address reproducibility and integration challenges across the behavioral sciences.

Altered lateralization of the cingulum in deployment-related traumatic brain injury: An ENIGMA military-relevant brain injury study

Traumatic brain injury (TBI) in military populations can cause disruptions in brain structure and function, along with cognitive and psychological dysfunction. Diffusion magnetic resonance imaging (dMRI) can detect alterations in white matter (WM) microstructure, but few studies have examined brain asymmetry. Examining asymmetry in large samples may increase sensitivity to detect heterogeneous areas of WM alteration in mild TBI. Through the Enhancing Neuroimaging Genetics Through Meta-Analysis Military-Relevant Brain Injury working group, we conducted a mega-analysis of neuroimaging and clinical data from 16 cohorts of Active Duty Service Members and Veterans (n = 2598). dMRI data were processed together along with harmonized demographic, injury, psychiatric, and cognitive measures. Fractional anisotropy in the cingulum showed greater asymmetry in individuals with deployment-related TBI, driven by greater left lateralization in TBI. Results remained significant after accounting for potentially confounding variables including posttraumatic stress disorder, depression, and handedness, and were driven primarily by individuals whose worst TBI occurred before age 40. Alterations in the cingulum were also associated with slower processing speed and poorer set shifting. The results indicate an enhancement of the natural left laterality of the cingulum, possibly due to vulnerability of the nondominant hemisphere or compensatory mechanisms in the dominant hemisphere. The cingulum is one of the last WM tracts to mature, reaching peak FA around 42 years old. This effect was primarily detected in individuals whose worst injury occurred before age 40, suggesting that the protracted development of the cingulum may lead to increased vulnerability to insults, such as TBI.

Cross-walk comparison of the DVBIC-TBICoE and LIMBIC-CENC combat-related concussion prospective longitudinal study datasets

OBJECTIVE

To describe and compare cohorts between two large, longitudinal, federally-funded TBI studies of Service members and veterans across demographic, self-report, and neuropsychological variables.

DESIGN

Analysis of data from the DVBIC-TBICoE and LIMBIC-CENC prospective longitudinal studies (PLS).

SETTING

Recruitment locations spanning Department of Defense and Veterans Affairs hospitals across the U.S.

PARTICIPANTS

1,463 participants enrolled in the DVBIC-TBICoE study and divided among non-injured (NIC) (n=191), injured control (IC) (n=349), mild TBI (mTBI) (n=682), and (moderate-severe-penetrating TBI (smcTBI) (n=241) subgroups. 1,550 participants enrolled in the LIMBIC-CENC study and divided between IC (n=285) and mTBI (n=1,265) subgroups. IC and mTBI study groups were compared across demographic and military characteristics, self-reported symptoms, and neuropsychological test scores.

INTERVENTIONS

None MAIN OUTCOME MEASURES: Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Military Version (PCL-C), TBI Quality of Life (TBI-QOL), Test of Premorbid Functioning (TOPF), Wechsler Adult Intelligence Scale-IV (WAIS-IV) Visual Puzzles, Symbol Search, Coding, Letter-Number Sequencing, and Digit Span, Trail Making Test (TMT), Delis-Kaplan Executive Functioning System (DKEFS) Verbal Fluency, Letter Fluency, and Category Fluency, California Verbal Learning Test-II (CVLT-II), and Grooved Pegboard (GP).

RESULTS

Compared to DVBIC-TBICoE, LIMBIC-CENC participants have higher enrollment age, education level, proportion of Black race, and time from injury as well as less combat deployments and are less likely to be married. The distribution of military service branches also differed. Further, symptom profiles differed between cohorts. LIMBIC-CENC participants endorsed higher posttraumatic stress disorder symptomatology. DVBIC-TBICoE study IC participants endorsed higher somatosensory and vestibular symptoms (medium effect sizes). Other symptom measure differences had very small effect sizes (≤0.2). Differences were found on many cognitive test results, but are difficult to interpret given the demographic differences and generally very small effect sizes.

CONCLUSIONS

The heavy use of NIH common data elements in both studies and collaboration with the DVBIC-TBICoE study team on development of the LIMBIC-CENC assessment battery enabled this comparative analysis. Results highlight unique differences in study cohorts, and adds perspective and interpretability for assimilating past and future findings.

Alternative Structure Models of the Traumatic Brain Injury Rehabilitation Needs Survey: A Veterans Affairs TBI Model Systems Study

OBJECTIVE

To explore the factor structure of the Rehabilitation Needs Survey (RNS).

DESIGN

Secondary analysis of observational cohort study who were 5-years post-traumatic brain injury (TBI).

SETTING

Five Inpatient Rehabilitation Facilities.

PARTICIPANTS

Veterans enrolled in the TBI Model Systems longitudinal study who completed the RNS at 5-year follow-up (N=378).

MAIN OUTCOME MEASURE(S)

RNS.

RESULTS

RNS factor structure was examined with exploratory factor analysis (EFA) with oblique rotation. Analyses returned 2- and 3-factor solutions with Cronbach alphas ranging from 0.715 to 0.905 and corrected item-total correlations that ranged from 0.279 to 0.732. The 2-factor solution accounted for 61.7% of the variance with ≥3 exclusively loading items on each factor with acceptable internal consistency metrics and was selected as the most parsimonious and clinically applicable model. Ad hoc analysis found the RNS structure per the EFA corresponded with elements of the International Classification of Functioning, Disability and Health (ICF) conceptual framework. All factors had adequate internal consistency (α≥0.70) and 20 of the 21 demonstrated good discrimination (corrected item-total correlations≥0.40).

CONCLUSIONS

The 2-factor solution of the RNS appears to be a useful model for enhancing its clinical interpretability. Although there were cross-loading items, they refer to complex rehabilitation needs that are likely influenced by multiple factors. Alternatively, there are items that may require alteration and redundant items that should be considered for elimination.

Can mild traumatic brain injury alter cognition chronically? A LIMBIC-CENC multicenter study

OBJECTIVE

While outcome from mild traumatic brain injury (mTBI) is generally favorable, concern remains over potential negative long-term effects, including impaired cognition. This study examined the link between cognitive performance and remote mTBIs within the Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) multicenter, observational study of Veterans and service members (SMs) with combat exposure.

METHOD

Baseline data of the participants passing all cognitive performance validity tests (n = 1,310) were used to conduct a cross-sectional analysis. Using multivariable regression models that adjusted for covariates, including age and estimated preexposure intellectual function, positive mTBI history groups, 1-2 lifetime mTBIs (nonrepetitive, n = 614), and 3 + lifetime mTBIs (repetitive; n = 440) were compared to TBI negative controls (n = 256) on each of the seven cognitive domains computed by averaging Z scores of prespecified component tests. Significance levels were adjusted for multiple comparisons.

RESULTS

Neither of the mTBI positive groups differed from the mTBI negative control group on any of the cognitive domains in multivariable analyses. Findings were also consistently negative across sensitivity analyses (e.g., mTBIs as a continuous variable, number of blast-related mTBIs, or years since the first and last mTBI).

CONCLUSIONS

Our findings demonstrate that the average veteran or SM who experienced one or more mTBIs does not have postacute objective cognitive deficits due to mTBIs alone. A holistic health care approach including comorbidity assessment is indicated for patients reporting chronic cognitive difficulties after mTBI(s), and strategies for addressing misattribution may be beneficial. Future study is recommended with longitudinal designs to assess within-subjects decline from potential neurodegeneration. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Associations between early sleep-disordered breathing following moderate-to-severe traumatic brain injury and long-term chronic pain status: a Traumatic Brain Injury Model Systems study

STUDY OBJECTIVES

To explore the relationship between polysomnography-derived respiratory indices and chronic pain status among individuals following traumatic brain injury (TBI).

METHODS

Participants (n = 66) with moderate to severe TBI underwent polysomnography during inpatient acute rehabilitation and their chronic pain status was assessed at 1- to 2-year follow-up as part of the TBI Model Systems Pain Collaborative Study. Pairwise comparisons across pain cohorts (ie, chronic pain, no history of pain) were made to explore differences on polysomnography indices.

RESULTS

Among our total sample, approximately three-quarters (74.2%) received sleep apnea diagnoses utilizing American Academy of Sleep Medicine criteria, with 61.9% of those endorsing a history of chronic pain. Of those endorsing chronic pain, the average pain score was 4.8 (standard deviation = 2.1), with a mean interference score of 5.3 (2.7). Pairwise comparisons revealed that those endorsing a chronic pain experience at follow-up experienced categorically worse indicators of sleep-related breathing disorders during acute rehabilitation relative to those who did not endorse chronic pain. Important differences were observed with elevations on central (chronic pain: 2.6; no pain: 0.8 per hour) and obstructive apnea (chronic pain: 15.7; no pain: 11.1 per hour) events, as well as oxygen desaturation indices (chronic pain: 19.6; no pain: 7.9 per hour).

CONCLUSIONS

Sleep-disordered breathing appears worse among those who endorse chronic pain following moderate-to-severe TBI, but additional research is needed to understand its relation to postinjury pain. Prospective investigation is necessary to determine how clinical decisions (eg, opioid therapy) and intervention (eg, positive airway pressure) may mutually influence outcomes.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Comparison of Sleep Apnea Assessment Strategies to Maximize TBI Rehabilitation Participation and Outcome (C-SAS); URL: https://clinicaltrials.gov/ct2/show/NCT03033901; Identifier: NCT03033901.

CITATION

Martin AM, Pinto SM, Tang X, et al. Associations between early sleep-disordered breathing following moderate-to-severe traumatic brain injury and long-term chronic pain status: a Traumatic Brain Injury Model Systems study. J Clin Sleep Med. 2023;19(1):135-143.

Associations of Military Service History and Health Outcomes in the First Five Years after Traumatic Brain Injury

For many years, experts have recognized the importance of studying traumatic brain injury (TBI) among active-duty service members and veterans. A majority of this research has been conducted in Veterans Administration (VA) or Department of Defense settings. However, far less is known about military personnel who seek their medical care outside these settings. Studies that have been conducted in civilian settings have either not enrolled active duty or veteran participants, or failed to measure military history, precluding study of TBI outcomes by military history. The purpose of the present study was to determine associations between military history and medical (prevalence of 25 comorbid health conditions), cognition (Brief Test of Adult Cognition by Telephone), and psychological health (Patient Health Questionnaire-9 [PHQ-9], Generalized Anxiety Disorder-7, suicidality [9th item from PHQ-9]) in the first 5 years after TBI. In this prospective study, we analyzed data from the TBI Model Systems National Database. Participants were 7797 individuals with TBI admitted to one of 21 civilian inpatient rehabilitation facilities from April 1, 2010, to November 19, 2020, and followed up to 5 years. We assessed the relationship between military history (any versus none, combat exposure, service era, and service duration) and TBI outcomes. We found specific medical conditions were significantly more prevalent 1 year post-TBI among individuals who had a history of combat deployment (lung disorders, post-traumatic stress disorder [PTSD], and sleep disorder), served in post-draft era (chronic pain, liver disease, arthritis), and served >4 years (high cholesterol, PTSD, sleep disorder). Individuals with military history without combat deployment had modestly more favorable cognition and psychological health in the first 5 years post-injury relative to those without military history. Our data suggest that individuals with TBI with military history are heterogeneous, with some favorable and other deleterious health outcomes, relative to their non-military counterparts, which may be driven by characteristics of service, including combat exposure and era of service.

Sensory Phenotypes for Balance Dysfunction After Mild Traumatic Brain Injury

BACKGROUND AND OBJECTIVES

Recent team-based models of care use symptom subtypes to guide treatments of individuals with chronic effects of mild traumatic brain injury (mTBI). However, these subtypes, or phenotypes, may be too broad, particularly for balance (e.g., vestibular subtype). To gain insight into mTBI-related imbalance, we (1) explored whether a dominant sensory phenotype (e.g., vestibular impaired) exists in the chronic mTBI population, (2) determined the clinical characteristics, symptomatic clusters, functional measures, and injury mechanisms that associate with sensory phenotypes for balance control in this population, and (3) compared the presentations of sensory phenotypes between individuals with and without previous mTBI.

METHODS

A secondary analysis was conducted on the Long-Term Impact of Military-Relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium. Sensory ratios were calculated from the sensory organization test, and individuals were categorized into 1 of the 8 possible sensory phenotypes. Demographic, clinical, and injury characteristics were compared across phenotypes. Symptoms, cognition, and physical function were compared across phenotypes, groups, and their interaction.

RESULTS

Data from 758 Service Members and Veterans with mTBI and 172 individuals with no lifetime history of mTBI were included. Abnormal visual, vestibular, and proprioception ratios were observed in 29%, 36%, and 38% of people with mTBI, respectively, with 32% exhibiting more than 1 abnormal sensory ratio. Within the mTBI group, global outcomes (p < 0.001), self-reported symptom severity (p < 0.027), and nearly all physical and cognitive functioning tests (p < 0.027) differed across sensory phenotypes. Individuals with mTBI generally reported worse symptoms than their non-mTBI counterparts within the same phenotype (p = 0.026), but participants with mTBI in the vestibular-deficient phenotype reported lower symptom burdens than their non-mTBI counterparts (e.g., mean [SD] Dizziness Handicap Inventory = 4.9 [8.1] for mTBI vs 12.8 [12.4] for non-mTBI, group × phenotype interaction p < 0.001). Physical and cognitive functioning did not differ between the groups after accounting for phenotype.

DISCUSSION

Individuals with mTBI exhibit a variety of chronic balance deficits involving heterogeneous sensory integration problems. While imbalance when relying on vestibular information is common, it is inaccurate to label all mTBI-related balance dysfunction under the vestibular umbrella. Future work should consider specific classification of balance deficits, including specific sensory phenotypes for balance control.

Relation of Mild Traumatic Brain Injury history to abnormalities on a preliminary Neuroendocrine screen; A multicenter LIMBIC-CENC analysis

PRIMARY OBJECTIVES

Determine if an abnormal preliminary neuroendocrine disorder (NED) blood test screen is associated with mild TBI (mTBI) history or post-concussiveclinical features.

RESEARCH DESIGN

Observational.

METHODS

Among 1,520 participants with military combatexposure, we measured randomly timed serum levels of insulin-likegrowth factor-1, thyroid stimulating hormone (TSH), and total testosterone as a preliminary NED screen. Using multivariable models, we analyzed relation of screen results in mTBI group membership and post-concussiveclinical features (fatigue, depression, cognitive symptoms, executive function, processing speed).

RESULTS

None of the mTBI positive groups, including repetitive (≥3 mTBI) and blast-related,differed from the non-TBIcontrols on rates of abnormal lab screen or rates of growth hormone deficiency (GHD), hypothyroidism or male hypogonadism in treatment records. Lab screen findings were also not associated with any clinical feature.

CONCLUSIONS

This study shows no evidence that remote mTBI(s) or implicated post-concussiveclinical features are linked to GHD, hypothyroidism or male hypogonadism. Large case-controlstudies incorporating more definitive neuroendocrine disorder NED testing (TSH plus thyroxine, early morning testosterone, LH, FSH, prolactin and GH provocative testing) are needed to determine whether mTBI(s) alone elevate one's risk for chronic NED and how best to select patients for comprehensive testing.

Olfactory Changes After Military Deployment Are Associated With Emotional Distress but Not With Mild Traumatic Brain Injury History

OBJECTIVE

The aim of the study was to identify the impact of mild traumatic brain injury history and current emotional status on olfactory functioning.

DESIGN

This was a cross-sectional study of 49 predominantly male, military veterans, reservists, and active duty service members with Operations Enduring Freedom, Iraqi Freedom, and New Dawn deployments and varying mild traumatic brain injury histories.

RESULTS

Those with a positive history of mild traumatic brain injury (n = 32) endorsed significantly higher rates of self-reported olfactory disturbance. However, there were no differences between the mild traumatic brain injury and no mild traumatic brain injury groups for rates of objective odor identification dysfunction (none vs. microsmia or more severe) or overall accuracy of odor identification. In keeping with this, self-reported olfactory disturbance also failed to associate with odor identification dysfunction. In both groups, those self-reporting olfactory disturbance reported significantly greater emotional distress, severity of posttraumatic stress symptoms, and attentional impulsivity. However, self-reported olfactory disturbance was not associated with other behavioral factors frequently attributed to TBI, such as aggression, motor impulsiveness, poor planning, and cognitive flexibility.

CONCLUSIONS

These findings indicate mild traumatic brain injury is not a risk factor for postacute microsomia among Operations Enduring Freedom, Iraqi Freedom, and New Dawn military veterans. Higher observed rates of self-reported olfactory disturbance in patients with mild traumatic brain injury may be a function of emotional distress rather than organic brain injury.

Remote blast-related mild traumatic brain injury is associated with differential expression of exosomal microRNAs identified in neurodegenerative and immunological processes

BACKGROUND

Blast traumatic brain injury (TBI) and subconcussive blast exposure have been associated, pathologically, with chronic traumatic encephalopathy (CTE) and, clinically, with cognitive and affective symptoms, but the underlying pathomechanisms of these associations are not well understood. We hypothesized that exosomal microRNA (miRNA) expression, and their relation to neurobehavioral outcomes among Veterans with blunt or blast mild TBI (mTBI) may provide insight into possible mechanisms for these associations and therapeutic targets.

METHODS

This is a subanalysis of a larger Chronic Effects of Neurotrauma Consortium Biomarker Discovery Project. Participants (n = 152) were divided into three groups: Controls (n = 35); Blunt mTBI only (n = 54); and Blast/blast+blunt mTBI (n = 63). Postconcussive and post-traumatic stress symptoms were evaluated using the NSI and PCL-5, respectively. Exosomal levels of 798 miRNA expression were measured.

RESULTS

In the blast mTBI group, 23 differentially regulated miRNAs were observed compared to the blunt mTBI group and 23 compared to controls. From the pathway analysis, significantly dysregulated miRNAs in the blast exposure group correlated with inflammatory, neurodegenerative, and androgen receptor pathways.

DISCUSSION

Our findings suggest that chronic neurobehavioral symptoms after blast TBI may pathomechanistically relate to dysregulated cellular pathways involved with neurodegeneration, inflammation, and central hormonal regulation.

Randomized trial of rTMS in traumatic brain injury: improved subjective neurobehavioral symptoms and increases in EEG delta activity

PRIMARY OBJECTIVE

While repetitive transcranial magnetic stimulation (rTMS) has shown efficacy for cognitive difficulties accompanying depression, it is unknown if it can improve cognition in persons with traumatic brain injury.

RESEARCH DESIGN

Using a sham-controlled crossover design, we tested the capacity of high frequency rTMS of the prefrontal cortex to improve neuropsychological performance in attention, learning and memory, and executive function.

METHODS

Twenty-six participants with cognitive complaints and a history of mild-to-moderate traumatic brain injury were randomly assigned to receive first either active or sham 10 Hz stimulation for 20 minutes (1200 pulses) per session for five consecutive days. After a one-week washout, the other condition (active or sham) was applied. Pre- and post-treatment measures included neuropsychological tests, cognitive and emotional symptoms, and EEG.

MAIN OUTCOMES AND RESULTS

Results indicated no effect of treatment on cognitive function. Subjective measures of depression, sleep dysfunction, post-concussive symptoms (PCS), and executive function showed significant improvement with stimulation, retaining improved levels at two-week follow-up. EEG delta power exhibited elevation one week after stimulation cessation.

CONCLUSIONS

While there is no indication that rTMS is beneficial for neuropsychological performance, it may improve PCS and subjective cognitive dysfunction. Long-term alterations in cortical oscillations may underlie the therapeutic effects of rTMS.

Advanced brain age in deployment-related traumatic brain injury: A LIMBIC-CENC neuroimaging study

OBJECTIVE

To determine if history of mild traumatic brain injury (mTBI) is associated with advanced or accelerated brain aging among the United States (US) military Service Members and Veterans.

METHODS

Eight hundred and twenty-two participants (mean age = 40.4 years, 714 male/108 female) underwent MRI sessions at eight sites across the US. Two hundred and one participants completed a follow-up scan between five months and four years later. Predicted brain ages were calculated using T1-weighted MRIs and then compared with chronological ages to generate an Age Deviation Score for cross-sectional analyses and an Interval Deviation Score for longitudinal analyses. Participants also completed a neuropsychological battery, including measures of both cognitive functioning and psychological health.

RESULT

In cross-sectional analyses, males with a history of deployment-related mTBI showed advanced brain age compared to those without (t(884) = 2.1, p = .038), while this association was not significant in females. In follow-up analyses of the male participants, severity of posttraumatic stress disorder (PTSD), depression symptoms, and alcohol misuse were also associated with advanced brain age.

CONCLUSION

History of deployment-related mTBI, severity of PTSD and depression symptoms, and alcohol misuse are associated with advanced brain aging in male US military Service Members and Veterans.

Clinical features of dementia cases ascertained by ICD coding in LIMBIC-CENC multicenter study of mild traumatic brain injury

OBJECTIVE

Describe dementia cases identified through International Classification of Diseases (ICD) coding in the Long-term Impact of Military-relevant Brain Injury Consortium - Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) multicenter prospective longitudinal study (PLS) of mild traumatic brain injury (mTBI).

DESIGN

Descriptive case series using cross-sectional data.

METHODS

Veterans Affairs (VA) health system data including ICD codes were obtained for 1563 PLS participants through the VA Informatics and Computing Infrastructure (VINCI). Demographic, injury, and clinical characteristics of Dementia positive and negative cases are described.

RESULTS

Five cases of dementia were identified, all under 65 years old. The dementia cases all had a history of blast-related mTBI and all had self-reported functional problems and four had PTSD symptomatology at the clinical disorder range. Cognitive testing revealed some deficits especially in the visual memory and verbal learning and memory domains, and that two of the cases might be false positives.

CONCLUSIONS

ICD codes for early dementia in the VA system have specificity concerns, but could be indicative of cognitive performance and self-reported cognitive function. Further research is needed to better determine links to blast exposure, blast-related mTBI, and PTSD to early dementia in the military population.

Executive function and relation to static balance metrics in chronic mild TBI: A LIMBIC-CENC secondary analysis

Introduction

Among patients with traumatic brain injury (TBI), postural instability often persists chronically with negative consequences such as higher fall risk. One explanation may be reduced executive function (EF) required to effectively process, interpret and combine, sensory information. In other populations, a decline in higher cognitive functions are associated with a decline in walking and balance skills. Considering the link between EF decline and reduction in functional capacity, we investigated whether specific tests of executive function could predict balance function in a cohort of individuals with a history of chronic mild TBI (mTBI) and compared to individuals with a negative history of mTBI.

Methods

Secondary analysis was performed on the local LIMBIC-CENC cohort (N = 338, 259 mTBI, mean 45 ± STD 10 age). Static balance was assessed with the sensory organization test (SOT). Hierarchical regression was used for each EF test outcome using the following blocks: (1) the number of TBIs sustained, age, and sex; (2) the separate Trail making test (TMT); (3) anti-saccade eye tracking items (error, latency, and accuracy); (4) Oddball distractor stimulus P300 and N200 at PZ and FZ response; and (5) Oddball target stimulus P300 and N200 at PZ and FZ response.

Results

The full model with all predictors accounted for between 15.2% and 21.5% of the variability in the balance measures. The number of TBI's) showed a negative association with the SOT2 score (p = 0.002). Additionally, longer times to complete TMT part B were shown to be related to a worse SOT1 score (p = 0.038). EEG distractors had the most influence on the SOT3 score (p = 0.019). Lastly, the SOT-composite and SOT5 scores were shown to be associated with longer inhibition latencies and errors (anti-saccade latency and error, p = 0.026 and p = 0.043 respectively).

Conclusions

These findings show that integration and re-weighting of sensory input when vision is occluded or corrupted is most related to EF. This indicates that combat-exposed Veterans and Service Members have greater problems when they need to differentiate between cues when vision is not a reliable input. In sum, these findings suggest that EF could be important for interpreting sensory information to identify balance challenges in chronic mTBI.

Auditory evoked brain potentials as markers of chronic effects of mild traumatic brain injury in mid-life

OBJECTIVE

Auditory event-related potential (ERP) correlates of pre-dementia in late-life may also be sensitive to chronic effects of mild traumatic brain injury (mTBI) in mid-life. In addition to mTBI history, other clinical factors may also influence ERP measures of brain function. This study's objective was to evaluate the relationship between mTBI history, auditory ERP metrics, and common comorbidities.

METHODS

ERPs elicited during an auditory target detection task, psychological symptoms, and hearing sensitivity were collected in 152 combat-exposed veterans and service members, as part of a prospective observational cohort study. Participants, with an average age of 43.6 years, were grouped according to positive (n = 110) or negative (n = 42) mTBI history. Positive histories were subcategorized into repetitive mTBI (3 + ) (n = 40) or non-repetitive (1-2) (n = 70).

RESULTS

Positive history of mTBI was associated with reduced N200 amplitude to targets and novel distractors. In participants with repetitive mTBI compared to non-repetitive and no mTBI, P50 was larger in response to nontargets and N100 was smaller in response to nontargets and targets. Changes in N200 were mediated by depression and anxiety symptoms and hearing loss, with no evidence of a supplementary direct mTBI pathway.

CONCLUSIONS

Auditory brain function differed between the positive and negative mTBI groups, especially for repetitive injury, which implicated more basic, early auditory processing than did any mTBI exposure. Symptoms of internalizing psychopathology (depression and anxiety) and hearing loss are implicated in mTBI's diminished brain responses to behaviorally relevant and novel stimuli.

SIGNIFICANCE

A mid-life neurologic vulnerability conferred by mTBI, particularly repetitive mTBI, may be detectable using auditory brain potentials, and so auditory ERPs are a target for study of dementia risk in this population.

Associations Among PTSD and Postconcussive Symptoms in the Long-Term Impact of Military-Relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium Prospective, Longitudinal Study Cohort

OBJECTIVE

To describe rates of mild traumatic brain injury (mTBI) with and without concurrent posttraumatic stress disorder a sample of former and current military personnel, and to compare the factor structure of the Neurobehavioral Symptom Inventory (NSI) based on whether participants sustained mTBI with and without a positive posttraumatic stress disorder (PTSD) screen.

SETTING

Participants recruited and tested at 7 Veterans Affairs (VA) sites and 1 military training facility as part of a national, longitudinal study of mental health, physical, and cognitive outcomes among veterans and service members. Participants: Total of 1540 former and current military personnel with a history of combat exposure.

DESIGN

Cross-sectional analysis of observational data, including confirmatory factor analysis. Main Measures: NSI and PTSD Checklist for DSM-5 (PCL-5).

RESULTS

Most participants (81.5%) had a history of mTBI and almost half of these screened positive for PTSD (40.5%); only 23.9% of participants without a history of mTBI screened positive for PTSD. Participants with a history of mTBI reported higher elevations of NSI and PCL-5 symptoms compared with those without a history of mTBI. Confirmatory factor analyses of the NSI demonstrated good model fit using a 4-factor structure (somatosensory, affective, cognitive, and vestibular symptoms) among groups of participants both with and without a history of mTBI.

CONCLUSION

Symptoms of mTBI and PTSD are strongly associated with each other among veterans and service members with a history of combat exposure. The 4-factor NSI structure is supported among participants with and without a history of mTBI. These findings suggest the potential benefit of a holistic approach to evaluation and treatment of veterans and service members with concurrent and elevated postconcussive and posttraumatic stress symptoms.

Extracellular Vesicle Proteins and MicroRNAs Are Linked to Chronic Post-Traumatic Stress Disorder Symptoms in Service Members and Veterans With Mild Traumatic Brain Injury

Symptoms of post-traumatic stress disorder (PTSD) are common in military populations, and frequently associated with a history of combat-related mild traumatic brain injury (mTBI). In this study, we examined relationships between severity of PTSD symptoms and levels of extracellular vesicle (EV) proteins and miRNAs measured in the peripheral blood in a cohort of military service members and Veterans (SMs/Vs) with chronic mTBI(s). Participants (n = 144) were divided into groups according to mTBI history and severity of PTSD symptoms on the PTSD Checklist for DSM-5 (PCL-5). We analyzed EV levels of 798 miRNAs (miRNAs) as well as EV and plasma levels of neurofilament light chain (NfL), Tau, Amyloid beta (Aβ) 42, Aβ40, interleukin (IL)-10, IL-6, tumor necrosis factor-alpha (TNFα), and vascular endothelial growth factor (VEGF). We observed that EV levels of neurofilament light chain (NfL) were elevated in participants with more severe PTSD symptoms (PCL-5 ≥ 38) and positive mTBI history, when compared to TBI negative controls (p = 0.024) and mTBI participants with less severe PTSD symptoms (p = 0.006). Levels of EV NfL, plasma NfL, and hsa-miR-139–5p were linked to PCL-5 scores in regression models. Our results suggest that levels of NfL, a marker of axonal damage, are associated with PTSD symptom severity in participants with remote mTBI. Specific miRNAs previously linked to neurodegenerative and inflammatory processes, and glucocorticoid receptor signaling pathways, among others, were also associated with the severity of PTSD symptoms. Our findings provide insights into possible signaling pathways linked to the development of persistent PTSD symptoms after TBI and biological mechanisms underlying susceptibility to PTSD.

Health symptoms after war zone deployment-related mild traumatic brain injury: contributions of mental disorders and lifetime brain injuries

PRIMARY OBJECTIVE

To gain a better understanding of the complex relationship between combat deployment-related mild traumatic brain injury (mTBI) and persistent post-concussive symptoms (PPCSs), taking into consideration a wide range of potentially mediating and confounding factors.

RESEARCH DESIGN

Cross-sectional.

METHODS AND PROCEDURES

Subjects were 613 U. S. military Veterans and Service Members who served during operations Enduring Freedom, Iraqi Freedom, or New Dawn (OEF/OIF/OND) and completed a structured interview of mental disorders and a battery of questionnaires. Hierarchical binary logistic regression analyses were used to test the hypotheses.

MAIN OUTCOMES AND RESULTS

After accounting for mental disorders, lifetime mTBIs outside of OEF/OIF/OND deployment, medical conditions, and injury/demographic characteristics, deployment-related mTBI continued to be associated with several PPCSs (headaches, sleep disturbance, and difficulty making decisions). Deployment-related mTBI was also associated with two symptoms not normally associated with mTBI (nausea/upset stomach and numbness/tingling).

CONCLUSIONS

After adjusting for a wide range of factors, OEF/OIF/OND deployment-related mTBI was still associated with PPCSs on average 10 years after the injury. These findings suggest that mTBI sustained during OEF/OIF/OND deployment may have enduring negative health effects. More studies are needed that prospectively and longitudinally track health and mental health outcomes after TBI.

787 OSA Risk is Associated with Number of White Matter Hyperintensities, But History of Mild TBI is Not: A LIMBIC-CENC Study

Introduction

Individuals with a history of mild traumatic brain injury (mTBI) have higher risk levels for obstructive sleep apnea (OSA). However, no studies have examined the association between OSA and white matter hyperintensities (WMHs) in this group. The purpose of this study is to explore the relationship between OSA risk, mTBI, and WMHs in a military cohort with a history of combat deployment.

Methods

Secondary analyses were conducted from a large clinical database of a multi-center, longitudinal study of current and former military personnel. Participants were included who had complete STOPBANG (sleep apnea risk) data and MRI. Univariable and multivariable regressions were conducted, including age, race, gender, education, hypertension, diabetes, history of mTBI, and STOPBANG score in the models.

Results

The final sample (N=1017) included participants with (n=823) and without (n=194) a history of mTBI. The sample was predominantly male (87%) with a median age of 38 (IQR; 32–48). WMHs were reported in 37% of the sample. Univariate analyses revealed that increasing age, female sex, hypertension, diabetes, and higher sleep apnea risk score were each positively associated with higher number of WMHs, while a history of lifetime mTBI exposure was not associated. Multivariable analyses revealed that of these factors, only age remained associated with WMH presence. When restricting the sample to the 37% with WMHs, OSA risk and female sex were each associated with higher number of WMHs (p&lt;.05), but history of mTBI was not.

Conclusion

Consistent with the literature in non-brain injured populations, age was the strongest predictor of WMH presence and number. In those with identified WMHs, OSA risk was a significant predictor of WMH number, while history of mTBI was not. Thus, in persons with mTBI, presence of WMHs may be linked to sleep comorbidities, providing potential treatment targets. Limitations include assessment of OSA rather than established diagnosis.

Support (if any)

Defense and Veterans Brain Injury Center (HT0014-19-C-004), DOD(W81XWH-13-2-0095), VA(I01 CX001135). The views expressed in this abstract are those of the authors and do not necessarily represent the official policy or position of the Defense Health Agency, Department of Defense, or any other U.S. government agency. For more information, please contact dha.TBICoEinfo@mail.mil. UNCLASSIFIED

FreeSurfer 5.3 versus 6.0: are volumes comparable? A Chronic Effects of Neurotrauma Consortium study

Automated neuroimaging methods like FreeSurfer ( https://surfer.nmr.mgh.harvard.edu/ ) have revolutionized quantitative neuroimaging analyses. Such analyses provide a variety of metrics used for image quantification, including magnetic resonance imaging (MRI) volumetrics. With the release of FreeSurfer version 6.0, it is important to assess its comparability to the widely-used previous version 5.3. The current study used data from the initial 249 participants in the ongoing Chronic Effects of Neurotrauma Consortium (CENC) multicenter observational study to compare the volumetric output of versions 5.3 and 6.0 across various regions of interest (ROI). In the current investigation, the following ROIs were examined: total intracranial volume, total white matter volume, total ventricular volume, total gray matter volume, and right and left volumes for the thalamus, pallidum, putamen, caudate, amygdala and hippocampus. Absolute ROI volumes derived from FreeSurfer 6.0 differed significantly from those obtained using version 5.3. We also employed a clinically-based evaluation strategy to compare both versions in their prediction of age-mediated volume reductions (or ventricular increase) in the aforementioned structures. Statistical comparison involved both general linear modeling (GLM) and random forest (RF) methods, where cross-validation error was significantly higher using segmentations from FreeSurfer version 5.3 versus version 6.0 (GLM: t = 4.97, df = 99, p value = 2.706e-06; RF: t = 4.85, df = 99, p value = 4.424e-06). Additionally, the relative importance of ROIs used to predict age using RFs differed between FreeSurfer versions, indicating substantial differences in the two versions. However, from the perspective of correlational analyses, fitted regression lines and their slopes were similar between the two versions, regardless of version used. While absolute volumes are not interchangeable between version 5.3 and 6.0, ROI correlational analyses appear to yield similar results, suggesting the interchangeability of ROI volume for correlational studies.

Post-mTBI Pain Interference in a U.S. Military Population: A Chronic Effects of Neurotrauma Consortium Study

INTRODUCTION

Chronic pain is a significant problem for service members and veterans with mild traumatic brain injury (mTBI). While the root cause of pain is not clearly understood, comorbidities may contribute to how their pain disrupts their functional status, a construct termed "pain interference." The purpose of this study is to examine the associations between mTBI, other comorbidities, and pain interference.

MATERIALS AND METHODS

The sample comprised participants with mTBI(s) from The Chronic Effects of Neurotrauma Consortium multicenter observational study. Potential concussive events were identified using a modified Ohio State University traumatic brain injury (TBI) Identification interview and then further with a structured interview. Pain interference was measured with the TBI quality-of-life pain interference score, which was categorized into insignificant, moderate, and high pain interference. Comorbidities of interest included anxiety, depression, post-traumatic stress disorder, insomnia, and arthritis. Multivariable relationships were analyzed using logistic regression.

RESULTS

The analysis sample included 346 participants with mTBI(s). In adjusted analysis, those with high pain interference were more likely to have history of ≥ 3 TBIs (odds ratio (OR) 3.1, 95% confidence interval [CI] 1.4, 6.9) and to have clinical levels of post-traumatic stress disorder (OR 5.4, 95% CI 1.9, 15.7), depression (OR 2.5, 95% CI, 1.0, 6.1), anxiety (OR 4.9, 95% CI, 2.0, 11.7), and sleep disturbances (OR 6.1, 95% CI 2.0, 19.0) versus those with insignificant pain interference.

CONCLUSION

These results identify clinical features of veterans and service members with mTBI(s) who are at highest risk for pain-related disability. These findings also demonstrate the need to consider mental health and sleep problems in their pain evaluation and treatment approach.

Potential Concussive Event Narratives of Post-9/11 Combat Veterans: Chronic Effects of Neurotrauma Consortium Study

INTRODUCTION

Deployment-related mild traumatic brain injury (mTBI) affects a significant proportion of those who served in Post-9/11 combat operations. The prevalence of head injuries, including those that lead to mTBI, is often reported quantitatively. However, service member (SM) and Veteran firsthand accounts of their potential concussive events (PCEs) and mTBIs can serve as a rich resource for better understanding the nuances and context of these exposures.

MATERIALS AND METHODS

Post-9/11 SMs and Veterans with a history of combat deployment were recruited through the Chronic Effects of Neurotrauma Consortium's observational study of deployment-related mTBI. During a comprehensive assessment, participants completed the Virginia Commonwealth University retrospective Concussion Diagnostic Interview, a specialized validated interview measure which obtains detailed narratives of deployment-incurred blast and non-blast-related PCEs. Qualitative thematic analysis was used to identify and code recurring themes within the narratives.

RESULTS

Among the sample of 106 SMs and Veterans, deployment-related mTBI was highly prevalent (67.0%). Over half (50.9%) of the participants identified a blast as the cause of their worst PCE, frequently with accompanying themes of self-reported acute neurological symptoms, intense physical blast forces, and tertiary head impact. Exposure to blast at close range, such as driving directly over an improvised explosive device, occurred in 24.7% of all blast-related narratives and in 59.3% of narratives where blast was identified as causing the worst PCE. Themes of potentially preventable head impacts experienced during noncombat circumstances were also frequent, accounting for 35% of all non-blast-related head injuries in the sample.

CONCLUSIONS

Prevalence of deployment-related close-range blast exposure, non-blast impact PCEs, and mTBIs among this Post-9/11 combatant sample was substantial, and in many cases potentially preventable. The use of detailed semi-structured interviews may help health care providers and policymakers to better understand the context and circumstances of deployment-related PCEs and mTBIs.

Obstructive Sleep Apnea Risk Is Associated with Cognitive Impairment after Controlling for Mild Traumatic Brain Injury History: A Chronic Effects of Neurotrauma Consortium Study

The contribution of sleep disturbance to persistent cognitive symptoms following a mild traumatic brain injury (mTBI) remains unclear. Obstructive sleep apnea (OSA) is very common, yet its relationship between risk factors for developing OSA and cognitive performance in those with history of mTBI has not been investigated. The current study examined OSA risk levels and its association with cognitive performance in 391 combat-exposed, post-911 veterans and service members (median age = 37 years) enrolled in the Chronic Effects of Neurotrauma Consortium (CENC) prospective multi-center study. Participants included those with and without mTBI (n = 326 and 65, respectively). When using clinical cut-offs, those with history of mTBI were more likely to be categorized as high risk for OSA (mTBI positive = 65% vs. mTBI negative = 51%). After adjustment for TBI status and demographic variables, increased OSA risk was significantly associated with worse performance on measures of complex processing speed and executive functioning (Wechsler Adult Intelligence Scale Fourth Edition Coding, Trail Making Test, part B) and greater symptom burden (Neurobehavioral Symptom Inventory). Thus, OSA, a modifiable behavioral health factor, likely contributes to cognitive performance following mTBI. Accordingly, OSA serves as a potential point of intervention to improve clinical and cognitive outcomes after injury.

Relationship of medical comorbidities to psychological health at 2 and 5 years following traumatic brain injury (TBI)

Objective: To examine the relationship between medical comorbidities and psychological health outcomes at 2 and 5 years following traumatic brain injury (TBI). Method: Veterans Affairs (VA) TBI Model System participants who completed a 2-year (n = 225) and/or 5-year (n = 283) follow-up with a comorbidities interview were included in the current study. Psychological health outcomes were assessed using the Patient Global Impression of Change (PGIC), Patient Health Questionnaire-9 (PHQ-9), and Satisfaction with Life Scale (SWLS). While controlling for known predictors of outcome, the relationship of overall comorbidity burden to psychological outcomes was examined cross-sectionally using generalized linear regression at 2 and 5 years post-TBI. Lasso regularization was used to examine relationships of specific comorbid conditions to outcome. Results: Greater comorbidity burden was significantly associated with lower satisfaction with life at 2 and 5 years post-TBI and was associated with greater depressive symptomatology at 5 years post-TBI. Chronic pain was associated with lower satisfaction with life and greater depressive symptoms at both 2- and 5-year follow-up. Sleep apnea was associated with lower satisfaction with life and greater depressive symptoms at 5-year follow-up. Rheumatoid arthritis was associated with lower satisfaction with life and lower levels of perceived improvement in health and well-being at the 5-year follow-up. Implications: Results suggest that medical comorbidities may have a cumulative impact on adverse psychological health outcomes in chronic stages of TBI. This study further highlights the complexity of patients with TBI and the importance of identifying medical comorbidities as they provide potential targets for intervention. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Health Services Utilization, Health Care Costs, and Diagnoses by Mild Traumatic Brain Injury Exposure: A Chronic Effects of Neurotrauma Consortium Study

OBJECTIVE

To compare Veterans Health Administration (VHA) diagnoses, health services utilization, and costs by mild traumatic brain injury (mTBI) group (blast-related [BR] mTBI vs non-blast-related [NBR] mTBI vs no mTBI) among Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF)/Operation New Dawn (OND) veterans in the Chronic Effects of Neurotrauma Consortium multicenter observational study.

DESIGN

Prospective cohort study.

SETTING

Four Veterans Affairs Medical Centers.

PARTICIPANTS

OEF/OIF/OND veterans (N=472) who used Veterans Affairs Medical Centers services between 2002-2017.

INTERVENTIONS

Not applicable. Lifetime mTBI history was assessed via semistructured interviews.

MAIN OUTCOME MEASURES

VHA diagnoses, health services utilization, and costs.

RESULTS

Relative to NBR mTBI and no mTBI, veterans with BR mTBI were more likely to be male, have greater combat, and have controlled and uncontrolled detonations exposures (median BR, 15.0 vs NBR, 3.0 vs no mTBI, 3.0). They also had higher prevalence of headache, posttraumatic stress disorder, and anxiety diagnoses. Veterans with BR had the highest site-adjusted mean annual VHA utilization (26.31 visits; 95% confidence interval [CI], 26.01-26.61) relative to NBR (20.43 visits; 95% CI, 20.15-20.71) and no mTBI (16.62 visits; 95% CI, 16.21-17.04) and highest site adjusted mean annual VHA outpatient costs ($6480; 95% CI, $5842-$7187) relative to NBR ($4901; 95% CI, $4392-$5468) and no mTBI ($4069; 95% CI, $3404-$4864).

CONCLUSIONS

Veterans with BR mTBI had higher exposure to combat and detonation. BR was associated with greater prevalence of select diagnoses and higher health services utilization and costs relative to NBR and no mTBI. The role of health care needs from mTBI polytrauma, other deployment-related exposures, and VHA access warrants future research.

Exosomal MicroRNAs in Military Personnel with Mild Traumatic Brain Injury: Preliminary Results from the Chronic Effects of Neurotrauma Consortium Biomarker Discovery Project

Chronic symptoms after mild traumatic brain injury (mTBI) are common among veterans and service members, and represent a significant source of morbidity, with those who sustain multiple mTBIs at greatest risk. Exosomal micro-RNAs (miRNAs), mediators of intercellular communication, may be involved in chronic TBI symptom persistence. Exosomal miRNA (exomiR) was extracted from 153 participants enrolled in the Chronic Effect of Neurotrauma Consortium (CENC) longitudinal study (no TBI, n = 35; ≥ 3 mTBIs (rTBI), n = 45; 1-2 mTBIs, n = 73). Analyses were performed with nCounter^® Human miRNA Expression Panels and Ingenuity Pathway Analysis (IPA) for identification of gene networks associated with TBI. Generalized linear models were used to analyze the predictive value of exomiR dysregulation and remote neurobehavioral symptoms. Compared with controls, there were 17 dysregulated exomiRs in the entire mTBI group and 32 dysregulated exomiRs in the rTBI group. Two miRNAs, hsa-miR-139-5p and hsa-miR-18a-5p, were significantly differentially expressed in the rTBI and 1-2 mTBI groups. IPA analyses showed that these dysregulated exomiRs correlated with pathways of inflammatory regulation, neurological disease, and cell development. Within the rTBI group, exomiRs correlated with gene activity for hub-genes of tumor protein TP53, insulin-like growth factor 1 receptor, and transforming growth factor beta. TBI history and neurobehavioral symptom survey scores negatively and significantly correlated with hsa-miR-103a-3p expression. Participants with remote mTBI have distinct exomiR profiles, which are significantly linked to inflammatory and neuronal repair pathways. These profiles suggest that analysis of exosomal miRNA expression may provide novel insights into the underlying pathobiology of chronic TBI symptom persistence.

Exosomal neurofilament light: A prognostic biomarker for remote symptoms after mild traumatic brain injury?

OBJECTIVE

To measure exosomal and plasma levels of candidate blood biomarkers in veterans with history of mild traumatic brain injury (mTBI) and test their relationship with chronic symptoms.

METHODS

Exosomal and plasma levels of neurofilament light (NfL) chain, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and vascular endothelial growth factor (VEGF) were measured using an ultrasensitive assay in a cohort of 195 veterans, enrolled in the Chronic Effects of Neurotrauma Consortium Longitudinal Study. We examined relationships between candidate biomarkers and symptoms of postconcussive syndrome (PCS), posttraumatic stress disorder (PTSD), and depression. Biomarker levels were compared among those with no traumatic brain injury (TBI) (controls), 1-2 mTBIs, and repetitive (3 or more) mTBIs.

RESULTS

Elevated exosomal and plasma levels of NfL were associated with repetitive mTBIs and with chronic PCS, PTSD, and depression symptoms. Plasma TNF-α levels correlated with PCS and PTSD symptoms. The total number of mTBIs correlated with exosomal and plasma NfL levels and plasma IL-6. Increased number of years since the most recent TBI correlated with higher exosomal NfL and lower plasma IL-6 levels, while increased number of years since first TBI correlated with higher levels of exosomal and plasma NfL, as well as plasma TNF-α and VEGF.

CONCLUSION

Repetitive mTBIs are associated with elevated exosomal and plasma levels of NfL, even years following these injuries, with the greatest elevations in those with chronic PCS, PTSD, and depression symptoms. Our results suggest a possible neuroinflammatory and axonal disruptive basis for symptoms that persist years after mTBI, especially repetitive.

A Prospective, Multicenter Study to Assess the Safety and Efficacy of Translingual Neurostimulation Plus Physical Therapy for the Treatment of a Chronic Balance Deficit Due to Mild‐to‐Moderate Traumatic Brain Injury

Objectives

Materials and Methods

Results

Conclusions

Self-report Pain Scale Reliability in Veterans and Service Members With Traumatic Brain Injuries Undergoing Inpatient Rehabilitation

INTRODUCTION

Pain in trauma patients with traumatic brain injury (TBI) may heighten cognitive-behavioral impairment and impede rehabilitation efforts. Multiple self-report pain assessment tools have been shown reliable in cognitively intact adults and children but are understudied in the cognitively impaired, particularly in persons with TBI. The objective of this study was to assess the utility and reliability of four pain assessment instruments among TBI patients during inpatient rehabilitation and the influence of cognitive impairment.

METHODS

Participants self-completed four pain intensity measures, the Verbal Descriptor Scale, Faces Pain Scale (Faces), Numerical Rating Scale (NRS), and Color-Enhanced Visual Analog Scale (CAS), during five study visits over a 2-week period. Data were collected on time to completion and most preferred pain measure. To assess scale reliability, participants re-rated their current pain. To assess scale responsiveness, standard mean response was measured across time and a worst past pain experience was rated. Cognitive impairment was assessed with the Memory, Orientation, and Amnesia Test.

RESULTS

The NRS was the most preferred measure by participants at every time point in the study. Mean pain measure completion time for all measures was under 11 seconds and did not significantly change during the study period. All scales showed very high test-retest reliability, with very strong correlations. Standard mean response from day 0 to 14 ranged from 0.387 to 0.532 across the scales. When stratified by cognitive impairment, the mean scores were consistently nominally higher for impaired participants, reaching statistical significance only for the CAS and Faces at baseline. In the cognitive impaired group, reliability for the Faces showed some weakening, as did the VAS to a milder degree.

CONCLUSIONS

All four pain measures demonstrated good utility, very high test-retest reliability, and satisfactory responsiveness. Greater cognitive impairment was associated with elevated pain ratings, especially in the Faces and CAS. The NRS was the most preferred by patients, regardless of cognitive impairment level.