Introduction: On January 8, 2020, there was a missile attack on a U.S. military base in Iraq resulting in a multiple casualty incident. Many U.S. service members sustained injuries, including mild traumatic brain injury (mTBI). Numerous studies have detailed the adverse health and career consequences of mTBI, but none have examined the effects of mTBI in a population that experienced the same combat incident. OBJECTIVES: (1) Determine the impact of mTBI on mental health and primary care utilization; (2) describe patterns of mental health diagnoses; and (3) identify the association between mTBI and military discharge.

Patients and Methods: The study sample included 199 service members injured during the missile attack. Of these, 102 sustained mTBI and 97 sustained non-mTBI injuries. Non-mTBI injuries were used as a comparison group for all analyses. Mental health diagnoses and healthcare utilization were abstracted from electronic medical databases for individuals pre- and post-injury. The average utilization for 36-months pre-injury was calculated and used as a baseline. Post-injury healthcare utilization was calculated as the difference from baseline, separated into 3-month increments (quarters) for a 36-month follow-up period. Mental health diagnoses were identified using International Classification of Diseases, 10th Revision codes for 36 months pre- and post-injury. Post-injury military discharge was identified from administrative records. Univariate analyses compared the mTBI with non-mTBI injury groups using t-tests. A mixed linear model was used to identify longitudinal changes in healthcare utilization during the follow-up period post-injury, while adjusting for age and sex.

Results: Both groups had significantly elevated primary and mental healthcare utilization in the post-injury period compared with the pre-injury period. For the mTBI group, mental healthcare utilization was elevated up to 36 months post-injury, compared with 21 months for the non-mTBI group. Elevated primary care utilization extended to 15 months post-injury for both groups. For post-injury mental health diagnoses, those who experienced mTBI compared with non-mTBI had a significantly higher prevalence of adjustment disorder (41.2% vs. 21.6%) and post-traumatic stress disorder (PTSD; 29.4% vs. 15.5%). The mTBI group was also significantly more likely to discharge from service post-injury than the non-mTBI group (22.5% vs. 8.2%).

Conclusions: These results suggest that mental health symptoms following mTBI among military personnel can last up to 3 years post-injury, possibly manifesting as adjustment disorder or PTSD. The higher frequency of military discharge in the mTBI group highlights the potential career consequences of this injury, possibly by way of the increase in mental health diagnoses. Further research is needed to determine the best treatment options for those experiencing mental health sequelae following mTBI and how to improve military retention rates. These findings may also be relevant when developing medical plans for civilian terror attacks where blast weaponry is employed.

Background: Military service member accounts, investigative journalism, and small-scale studies have fueled growing concern about the health effects of repeated low-level blast (LLB) occupational exposure for service members. An emerging line of Department of Defense research uses military occupation (MOS) as a proxy for LLB risk to evaluate health. In this study, we extend this work by applying two published MOS-LLB risk classifications (i.e., Belding; Carr) to a large post-deployment sample and model health outcomes related to LLB exposure risk.

Methods: The analytic sample included 477,746 active duty enlisted Army soldiers returning from Afghanistan/Iraq deployments in FYs 2008-2014, from the Substance Use and Psychological Injury Combat Study. Soldiers were categorized by their LLB risk exposure using the two risk classification strategies as high, medium, low, or mixed for the exposure period (i.e., FY05 through the end of the index deployment [first Afghanistan/Iraq deployment ending in FY2008-2014]). The Belding classification uses broader Department of Defense occupational codes, and the Carr classification uses a more specific set of Army MOS codes. Cox proportional hazard modeling was used to examine the association between LLB risk exposure level and diagnoses for mental health, substance use disorder, pain, and suicide/self-harm during the outcome window (i.e., end of index deployment through censoring at deactivation, end of enlistment, or end of FY2016). Covariates included sociodemographic and military characteristics, and prior history of the health outcomes during the exposure period. Models were run separately for the Belding and Carr MOS-LLB risk classification.

Results: Almost 35% of soldiers were classified as high LLB risk using the Belding classification, compared to 6% with the Carr classification. In both the Belding and Carr adjusted models, soldiers with high LLB exposure had higher hazards for substance use disorder (Belding HR 1.21, 95% CI 1.19-1.23; Carr HR 1.19, 95% CI 1.15-1.22), mental health disorder (Belding HR 1.09, 95% CI 1.08-1.10; Carr HR 1.03, 95% CI 1.01-1.05) and suicide/self-harm (Belding HR 1.08, 95% CI 1.05-1.12; Carr HR 1.09, 95% CI 1.03-1.16) in the outcome window. Soldiers classified as high LLB risk had lower hazards for pain diagnoses in the Belding model only (HR 0.99, 95% CI 0.98-1.00).

Discussion: In this large sample of enlisted active duty soldiers, those with high LLB risk occupations had an increased hazard for substance use, mental health, and suicide/self-harm diagnoses in the years following deployment. However, high LLB risk occupations were associated with reduced hazard for pain diagnoses following deployment. Results were similar for soldiers classified as high LLB risk using both the broad occupational categories and the more specific Army-specific MOS categories. Future models will examine if results remain consistent when examining risk for incident outcomes.

Introduction: Recent studies suggest the cumulative effects of repeat blast exposure in military personnel may lead to premature cognitive decline and disturbance of mood, behavior and executive function. Recent studies also suggest a possible relationship to suicidal behavior in Veterans. US Special Operations Forces are a high-risk population for such injuries related to both frequent combat exposure and the use of heavy weapons systems such as heavy mortars, shoulder launched rocket systems, and breaching charges. This retrospective cohort study examines the characteristics of 100 active-duty United States Special Operations Forces members admitted to the Walter Reed National Military Medical Center's inpatient Brain Injury Medicine Unit for evaluation of cognitive impairment.

Methods: This study retrospectively analyzed medical records to gather comprehensive data on the patients' demographics, service duration, blast and impact head injury exposure. Patient characteristics were correlated with findings on brain imaging, neuropsychological testing, endocrine and biochemical measures, polysomnography, and neurological examination. The patterns of cognitive complaints and clinical findings were correlated with diagnoses, including primary and secondary TBI-related conditions and comorbidities such as PTSD, depression, and other neuropsychiatric disorders.

Results: The analysis revealed a diverse range of TBI frequency and severities, and a high prevalence of comorbid psychiatric conditions, sleep disorders, and lifestyle factors with compounding adverse effects on cognition. The pattern of impairment due to mood and sleep disorders appears distinct from that displayed with individuals with radiologically confirmed parenchymal brain injury. Mood and sleep disorders appear to be distinguished by attention deficits, variable performance and fatigue on neuropsychological testing. A majority of the cohort presented with repeated mild TBIs, often compounded by orthopedic injuries and pain syndromes, underscoring the complex clinical needs of this population.

Discussion: The findings emphasize the importance of specialized neuropsychiatric care embedded in an interdisciplinary and holistic approach in managing the sequelae of TBI among Special Operations Forces. This approach plays a pivotal role in mitigating long-term neurobehavioral consequences, enhancing recovery and force readiness. The study underscores the need for ongoing research, suggesting that a future prospective study could further elucidate the outcomes post-discharge, potentially guiding enhancements in treatment protocols and long-term support strategies for these service members.

Conclusions: The Walter Reed National Military Medical Center's Brain Injury Medicine Unit serves as an indispensable resource for Special Operations Forces suffering from cognitive and emotional disturbances to ascertain the potential contribution of TBI and other neuropsychiatric morbidities. By detailing the demographic and clinical characteristics of this cohort, this study lays the groundwork for future prospective research aimed at optimizing treatment outcomes and developing targeted interventions to support the health and operational effectiveness of these elite military personnel.

Background: Posttraumatic stress disorder (PTSD), mild traumatic brain injury (TBI), and blast exposure are associated with long-term cognitive outcomes in Veterans. Despite overlap in symptoms and frequent co-occurrence, work suggests that these conditions and exposures affect cognition independently. The present analysis identifies neurobiological pathways by which PTSD, mild TBI, and blast exposure affect neuropsychological functioning long-term.

Methods: Participants were 181 US combat Veterans (88% male, M age=41.60 years). Lifetime PTSD diagnoses, TBI, and blast exposure histories were obtained through structured clinical interviews. Cognitive function was assessed using neuropsychological testing, and functional brain connectomes were mapped using magnetoencephalography. Linear regression analyses identified factors influencing cognitive function, including connectome metrics, deployment-related TBI, blast exposure, PTSD, and their interaction effects.

Results: Results identified two connectome metrics that influenced outcomes in the presence of blast exposure. Significant conditional effects were present for Maximum K Core and attention (B=-0.12, p=.004) as well as the proportion of Alpha band connectivity and complex attention (B=-10.97, p=.042). Both effects followed the same pattern: performance was better on cognitive tests as each connectome metric increased, and this effect was stronger as blast severity increased. The relationship between TBI and cognition was dependent on two connectome metrics. The conditional effect was significant nodes and general ability (B=-0.25, p=.007), degree and general ability (B=-4.46, p=.009), as well as degree and perceptual reasoning (B=-3.25, p=.002). Interaction effects followed a similar pattern, such that when TBI as absent, performance was better as connectome metrics increased. However, when TBI was present, performance was poorer as connectome metrics increased. Adjusted main effects demonstrated that several aspects of the functional connectome were directly associated with cognitive outcomes. Modularity was positively associated with perceptual reasoning (B=16.05, p=.028). Alpha frequency was positively associated with processing speed (B=2.49, p=.049) and full scale IQ (B=9.73, p=.031). K Core Degree (B=-1.53, p=.002), rich Club metrics (B=-5.75, p=.006), and connection strength (B=-0.71, p=.004) were negatively associated with verbal fluency, among other cognitive outcomes.

Conclusions: These findings demonstrate that the relationship between the brain’s functional connectome and cognitive function is different in individuals with blast exposure and TBI history, independent of the presence of PTSD and effects of other covariates like age, education, and racial/ethnic background. This suggests that blast exposure and TBI affect cognition through a distinct neurological pathway, potentially representing effects of neurotrauma. This highlights the potential for targeted treatments aimed at normalizing the connectome to improve cognitive function in Veterans with a history of blast exposure or TBI.

A high proportion of military personnel are exposed to primary blast forces as part of training and/or combat. These forces can affect brain structure and function, resulting in concussive neurotrauma. However, most service-related blast exposures are considered subconcussive and do not result in overt clinical symptoms. Preclinical work suggests subconcussive exposures can affect brain structure and function in a similar manner to concussive exposures; however, this has not been demonstrated beyond the acute stage in humans. The primary objective of the current study is to identify the characteristics of subconcussive blast exposure associated with long-term differences in brain structure and function.
Participants included 107 US Military Veterans on average 10 years following deployment and without history of military-related traumatic brain injury (TBI). Blast exposure was evaluated using the Salisbury Blast Interview. Outcomes included ROI brain volumes and metrics describing aspects of the brain’s functional connectome. Linear regression was conducted with brain volume and connectome metrics as the dependent variable. Blast exposure characteristics were evaluated in separate models including covariates (age, sex, intracranial volume). Cluster analysis was conducted to identify patterns of exposure associated with changes to brain structure and function. False discovery rate corrected for multiple comparisons.
Two broad patterns of results were observed. First, characteristics describing the average severity across exposures were related to aspects of the functional connectome including the Rich Club, lower average frequency at which communication occurs, and gamma bandwidth connections. These characteristics were also related to left middle temporal gyrus and hippocampal volume. Second, blast characteristics describing the frequency of exposures were related to connections in the theta bandwidth and left superior frontal gyrus volume.
Cluster analysis identified three groups: unexposed, mild, and moderate exposure. Group differences were present for the frequency at which communication occurs and connections in the gamma bandwidth, as well as left middle temporal gyrus and hippocampal volume. Post-hoc analyses revealed that the unexposed group differed from both exposed groups, but the exposed groups did not differ from each other.
Results demonstrate two patterns of long-term changes in the functional connectome and brain volumes, one associated with the average severity of blast exposures and one with the frequency of blast exposures. This contrasts with blast exposure more generally (including both concussive and subconcussive events) where maximum severity and close-range exposures are the strongest predictors. The current results demonstrate that negative outcomes are unlikely to occur after a single subconcussive event, likely due to the lower severity of these events. Repeated exposure to sufficiently severe events is likely required for neurological effects to be observed following subconcussive blast exposure. These results identify neurological differences associated with subconcussive blast exposure that can be investigated as potential pathways explaining alterations in clinical presentations.

Background: The rate of traumatic brain injuries (TBI) in military service members has continued to increase over the past 25 years, with nearly 500,000 United States military service members sustaining a TBI since 2000. A history of TBI has been associated with an increased lifetime risk for developing mild cognitive impairment (MCI). Further, such changes may occur earlier in these individuals than in those without a history of TBI. This retrospective study sought to determine if there is an association between a history of TBI and risk for early-onset MCI (defined as appearing before age 65).

Methods: The United States Veteran’s Administration Informatics and Computing Infrastructure (VINCI) database was utilized to select a cohort of former military service members that had medical record data that included clinical neurological assessment. This dataset was then limited to those that had information on history of TBI as of 2008 and then these records were queried for ICD-9 and ICD-10 diagnoses of MCI between 2008-2020. A Fine-Gray competing risk model was used, with age to the first assessment used as the time axis.

Results: A total of 316,269 patients had clinical neurological assessment records. Of these, a total of 74,971 military service members (87% male, 68% Caucasian, mean age at first assessment 42 ± 13 years) had a reported TBI history. Those that reported a positive history of sustaining a TBI (3.8%; n=2,902) were more than twice as likely to have a diagnosis code for MCI as those without a history of TBI (Hazard ratio [HR]: 2.35, 95% CI: 2.24-2.46). This risk was similar when adjusted for race and gender. For those that sustained a TBI, female veterans were less likely to experience cognitive impairment than males (HR female 1.89 [CI: 1.59-2.25] versus HR male 2.36 [CI: 2.25-2.48]; interaction p value < 0.001). Regardless of sex, those that experienced a mild TBI (n=678) were less likely to be given a diagnosis of MCI than those that experienced a severe TBI (n=2,224; HR 1.66 [CI: 1.49-1.84] versus HR 2.62 [CI:2.48-2.76], respectively).

Discussion: Those with a history of TBI were more likely to have a diagnosis of early-onset MCI than those with no history of TBI. This risk was higher for those with more severe injuries, and in male patients. Given the prevalence of TBI, policies should be put in place to support prevention, early detection, and treatment of this common injury and its long-term consequences.

Although science regarding means by which to improve brain health continues to move forward, a significant disconnect between research findings and clinical practice remains. This is particularly true in terms of brain health, where clinicians and patients alike struggle to connect interventions focused on physical and mental health functioning to overall brain health (e.g., cognitive functioning). To address this real-world problem, the Department of Veterans Affairs is funding a Brain Health Coordinating Center (BHCC) to improve quality and outcomes of care, with the goal of promoting brain health and preventing brain injuries (e.g., cerebral vascular accidents) and brain-based diseases (e.g., dementia). BHCC efforts will be guided by the Learning Health Systems (LHS) framework. Adoption of the LHS framework has been shown to reduce quality gaps. During this presentation BHCC leadership will: introduce the LHS framework; discuss initial targets for brain health improvement (i.e., blood pressure, depression, sleep); highlight processes and evidence-based tools (e.g., metrics, dashboard) planned for use to modify multi-dimensional factors contributing to overall Veteran brain health; and introduce measurement-based care (i.e., systematic assessment of data used to guide patient and provider clinical decision making) as a core clinical practice. For example, even though depression is known to impact short- and long-term brain health, at present only about a third of individuals within the Veterans Health Administration with diagnosed depression are receiving systematic measurement of their symptoms (i.e., Patient Health Questionnaire-9) to evaluate treatment progress. Variability in measure administration by provider and patient cohorts is notable. In addition to measuring patient-, provider-, and facility-level outcomes, the BHCC team will be evaluating implementation efforts using the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, Maintenance). Long-term the team plans on creating a Brain Health Vital Sign score, derived from electronic medical record data to: highlight the current state of individual Veteran’s brain health; identify factors that are contributing to the individual’s brain health; and, promote personalized strategies (within and outside the medical system) to promote brain health. It is expected that efforts outlined above will contribute to Veterans receiving more equitable care, as well as decrease the existing gap between research and clinical practice.

Importance: Sleep problems are common and disabling among Veterans with traumatic brain injury (TBI), often reflecting underlying conditions such as insomnia disorder, rates of which are higher among individuals with TBI. Insomnia is characterized by difficulty initiating or maintaining sleep, waking earlier than desired, and daytime impairment. High-quality sleep is essential for recovery from TBI and overall well-being, making effective management of insomnia disorder essential for this population. Insomnia treatment for Veterans with TBI is often initiated within the Veterans Health Administration (VHA) Polytrauma/TBI System of Care (PSC), a national network of interdisciplinary teams with specialized expertise in TBI and related conditions. Insomnia treatment in this setting should follow VA/DoD Clinical Practice Guidelines, which include a recommendation that cognitive behavioral therapy for insomnia (CBT-I) be provided as first-line treatment over sleep medications. This recommendation is based on evidence that CBT-I provides longer-lasting benefits and that medications can have side effects, some of which are especially salient for Veterans with TBI (e.g., potential for abuse). While gaps in guideline-concordant insomnia treatment have been noted in other VHA settings, little is known regarding insomnia disorder treatment among Veterans receiving PSC services.

Objective: First, to describe guideline-concordant receipt of CBT-I vs. sleep medications among Veterans receiving PSC services. Second, to identify patient- and facility-level factors associated with receipt of CBT-I vs. sleep medications in this population.

Methods: This retrospective cohort study analyzed VHA medical records of Veterans who: 1) received their first PSC encounter after 10/1/2019; and, 2) received either CBT-I or a newly prescribed sleep medication in the year following their initial PSC encounter (with no prior treatment in the preceding two years). A descriptive analysis examined the receipt of CBT-I vs. sleep medications. Mixed effects regression modelled the likelihood of receiving first-line CBT-I vs. sleep medications based on sociodemographic (e.g., age), clinical (e.g., psychiatric conditions), spatial access (e.g., drive time), and facility-level factors (e.g., facility complexity).

Results: Among the 18,293 Veterans receiving insomnia disorder treatment, only 11% received first-line CBT-I. Older Veterans; Native Hawaiian/Pacific Islander and Hispanic Veterans; those with bipolar disorder, depression, and alcohol use or other substance use disorder; and those with extended drive times were less likely to receive CBT-I.

Conclusions: Adherence to guidelines recommending CBT-I over sleep medications is low within the PSC, which may undermine long-term outcomes and increase exposure to sleep medication side effects among Veterans with TBI. Future research is needed to clarify barriers to delivering CBT-I in the PSC and to develop targeted strategies for promoting its implementation, especially among older, geographically disadvantaged Veterans, as well as those with psychiatric or substance use disorders.