Deployment Traumatic Brain Injury Research Articles

The Functional Connectome and Long-Term Symptom Presentation Associated With Mild TBI and Blast Exposure in Combat Veterans.

Mild traumatic brain injury (TBI) sustained in a deployment environment (deployment TBI) can be associated with increased severity of long-term symptom presentation, despite the general expectation of full recovery from a single mild TBI. The heterogeneity in effects of Deployment TBI on the brain can be difficult for a case-control design to capture. The functional connectome of the brain is an approach robust to heterogeneity, that allows global measurement of effects using a common set of outcomes. The present study evaluates how differences in the functional connectome relate to remote symptom presentation following combat deployment and determines if deployment TBI, blast exposure, or posttraumatic stress disorder (PTSD) are associated with these neurological differences. Participants included 181 Iraq and Afghanistan combat-exposed veterans approximately 9.4 years since deployment. Structured clinical interviews provided diagnoses and characterization of TBI, blast exposure, and PTSD. Self-report measures provided characterization of long-term symptoms (psychiatric, behavioral health, and quality of life). Resting-state magnetoencephalography (MEG) was used to characterize the functional connectome of the brain individually for each participant. Linear regression identified factors contributing to symptom presentation including relevant covariates, connectome metrics, deployment TBI, blast exposure PTSD, and conditional relationships. Results identified unique contributions of aspects of the connectome to symptom presentation. Further, several conditional relationships were identified demonstrating that the connectome was related to outcomes only in the presence of deployment-related TBI (including blast-related TBI, primary blast TBI, and blast exposure). No conditional relationships were identified for PTSD; however, the main effect of PTSD on symptom presentation was significant for all models. These results demonstrate that the connectome captures aspects of brain function relevant to long-term symptom presentation, highlighting that deployment-related TBI influences symptom outcomes through a neurological pathway. These findings demonstrate that changes in the functional connectome associated with deployment-related TBI are relevant to symptom presentation over a decade past the injury event, providing a clear demonstration of a brain based mechanism of influence.

4 TBI and Blast Disrupt Normal Relationships Between Brain Function, Cognitive Performance, and Psychiatric Symptom Severity

Objective:Determine how characteristics of deployment mild traumatic brain injury (TBI) and blast exposure influence the relationship between the functional brain connectome with cognitive outcomes and symptom severity.Participants and Methods:N = 181 Iraq and Afghanistan combat veterans completed structured clinical interviews, cognitive testing, self-report questionnaires, and magnetoencephalography (MEG). MEG data were acquired in the resting-state with eyes open. MEG data were beamformed to identify brain regions active at rest. Functional brain connectomes representing the unique network present for a given individual were created using active brain regions identified for each participant. Network metrics describing these connectomes were calculated at the participant level. Cognitive tests included the WAIS-IV, Trail Making Test Parts A&B, and the Controlled Oral Word Association test. Due to differences in normative data across tests, raw scores were used in analyses. Symptom measures included the PTSD Checklist - 5 (PCL-5), Patient Health Questionnaire (PHQ-9), Neurobehavioral Symptoms Inventory (NSI), Quality of Life After Brain Injury (QOLIBRI), Pittsburgh Sleep Quality Index (PsQi), the Distress Tolerance Scale (DTS), and the PROMIS Pain Interference Scale (PROMIS-PI).Results:Hierarchical linear regression analyses revealed that several network metrics were significantly related to both cognitive outcomes and symptom severity after adjusting for demographic covariates and clinical characteristics.The relationship between Global Efficiency (GE) and cognitive outcomes was moderated by deployment TBI on the WAIS-IV Full Scale Index (FSI), Perceptual Reasoning Index (PRI), and General Ability Index (GAI). In all cases, when deployment TBI was absent, greater GE was associated with poorer cognitive scores. The relationship between GE and symptom severity was moderated by the severity of blast exposure. Greater GE was associated with lower symptom severity at lower blast severities for the PHQ-9 and QOLIBRI A (thinking) and E (negative emotions). Moderation effects were also observed for the PSQI. In the absence of deployment TBI, greater GE was associated with better sleep quality; however, in the presence of deployment TBI, greater GE was associated with poorer sleep quality. Other connectome-outcome relationships were not consistently moderated by Deployment TBI or blast historyConclusions:Results demonstrated relationships between several aspects the functional connectome of the brain with both cognitive outcomes and symptom severity beyond effects of common demographic and clinical variables. Moderation analyses revealed that the relationship between GE of the connectome and outcomes is frequently disrupted by deployment TBI and blast. GE is a measure of the ease of information transfer through the network. These results identified consistent relationships between GE and outcomes in the absence of deployment TBI or blast, but these relationships disappear when deployment TBI or blast are present. Participants in this study were on average 11 years post-TBI or blast exposure, suggesting these are chronic rather than acute effects. GE was significantly correlated with most symptom severity measures as well as the WAIS-IV PRI, GAI, VCI, and FSI. Future efforts to normalize the relationship between GE and outcomes following TBI may improve rehabilitation outcomes and directly affect areas of concern commonly reported by service members following TBI or blast exposure.

Alterations in the Topology of Functional Connectomes Are Associated with Post-Traumatic Stress Disorder and Blast-Related Mild Traumatic Brain Injury in Combat Veterans.

Post-traumatic stress disorder (PTSD) is a common condition in post-deployment service members (SM). SMs of the conflicts in Iraq and Afghanistan also frequently experience traumatic brain injury (TBI) and exposure to blasts during deployments. This study evaluated the effect of these conditions and experiences on functional brain connectomes in post-deployment, combat-exposed veterans. Functional brain connectomes were created using 5-min resting-state magnetoencephalography data. Well-established clinical interviews determined current PTSD diagnosis, as well as deployment-acquired mild TBI and history of exposure to blast. Linear regression examined the effect of these conditions on functional brain connectomes beyond covariates. There were significant interactions between blast-related mild TBI and PTSD after correction for multiple comparisons including number of nodes (non-standardized parameter estimate [PE] = -12.47), average degree (PE = 0.05), and connection strength (PE = 0.05). A main effect of blast-related mild TBI was observed on the threshold level. These results demonstrate a distinct functional connectome presentation associated with the presence of both blast-related mild TBI and PTSD. These findings suggest the possibility that blast-related mild TBI alterations in functional brain connectomes affect the presentation or progression of recovery from PTSD. The current results offer mixed support for hyper-connectivity in the chronic phase of deployment TBI.

Differential effects of deployment and nondeployment mild TBI on neuropsychological outcomes.

Objective: Mild traumatic brain injury (TBI) that occurs in a deployment environment is characteristically different from mild TBI that occurs outside of deployment. This study evaluated differential and interaction effects of deployment and nondeployment mild TBI on cognitive and behavioral health outcomes. Research Method: Combat veterans (N = 293) who passed performance-validity measures completed the Mid-Atlantic MIRECC Assessment of TBI (MMA-TBI), Clinician-Administered Posttraumatic Stress Disorder (PTSD) Scale (CAPS-5), a neuropsychological assessment battery, and self-report questionnaires. A 2 × 2 × 2 analysis of variance (ANOVA) was conducted to evaluate the main and interaction effects across mild TBI groups and PTSD diagnosis. Results: Deployment TBI was associated with poorer outcomes on several cognitive tests: Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV); Working Memory Index (WMI; p = .018); Trail Making Test A (TMT-A; p < .001); and Trail Making Test B (TMT-B; p = .002). Deployment TBI and PTSD were also associated with increased PTSD, depressive, and neurobehavioral symptoms; pain interference; and poorer sleep quality. Nondeployment TBI had no effect on cognitive performance and was associated only with poorer sleep quality. PTSD had the strongest associations with symptom measures and deployment TBI with cognitive outcomes. There were no significant interaction effects after adjusting for multiple comparisons. Conclusions: Remote outcomes associated with mild deployment TBI are different from those associated with nondeployment mild TBI and are robust beyond PTSD. This suggests that the environment surrounding a TBI event influences cognitive and symptom sequelae. Veterans who experience mild TBI during deployment may report changes in cognition, but most will continue to function within the expected range. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Pain interference and quality of life in combat veterans: Examining the roles of posttraumatic stress disorder, traumatic brain injury, and sleep quality.

The goal of this study was to examine the associations among posttraumatic stress disorder (PTSD), traumatic brain injury (TBI), sleep quality, pain interference, and quality of life in combat veterans. Veterans (N = 289, 86.51% male) completed the Mid-Atlantic MIRECC Assessment of Traumatic Brain Injury, the Clinician-Administered PTSD Scale for DSM-5, and measures of sleep quality, pain interference, and quality of life. Hierarchical linear regressions evaluated associations between PTSD severity, deployment TBI severity, sleep quality, and the outcomes of pain interference and quality of life after adjusting for demographic variables and the number of nondeployment TBIs. PTSD severity, B = 0.15, SE B = 0.04, deployment TBI severity, B = 3.98, SE B = 1.01, and sleep quality, B = 0.74, SE B = 0.13, were significantly associated with pain interference, p < .001. PTSD severity, B = -0.57, SE B = 0.07, and pain interference, B = -0.45, SE B = 0.11, were significantly, independently associated with quality of life, p < .001. However, pain interference, B = -0.24, SE B = 0.11, was no longer significantly associated with quality of life when sleep quality, B = -1.56, SE B = 0.25, was included in the model. There was no significant association between deployment TBI severity and quality of life. Interactions among the studied variables were not significant for either of the outcome variables. PTSD symptom severity, deployment TBI history, and sleep quality may be important to consider in treatment planning for veterans experiencing pain-related functional interference. For veterans with numerous conditions comorbid with pain, treatment plans may include interventions targeting sleep and PTSD to maximize quality of life improvements. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Deployment and Psychological Correlates of Suicide Ideation: A Prospective, Longitudinal Study of Risk and Resilience Among Combat Veterans.

Suicide rates among military personnel have risen in part due to war zone deployments. Yet, the degree to which deployment-related stressors, in combination with preexisting and co-occurring psychiatric symptoms and individual resilience factors, contribute to suicide ideation (SI) remains unclear. The current study leverages prospective, longitudinal data to examine both risk and protective factors associated with SI in deployed service members. Participants were 1,805 active duty enlisted Marines and Navy service members assessed before and after a 7-month deployment for SI, preexisting and concurrent symptoms of depression, post-traumatic stress disorder (PTSD), alcohol consumption, as well as prior and deployment-related traumatic brain injury (TBI). Current self-reported psychological resilience and social support were analyzed as potential protective factors. Rates of SI were 7.3% and 3.9% before and after deployment, respectively. Of those with post-deployment SI, 68.6% were new-onset cases. Multivariate regression revealed that concurrent mild depression was the strongest risk factor (odds ratio [OR] = 10.03, 95% CI 5.28-19.07). Other significant risk factors included prior SI (OR = 3.36, 95% CI 1.60-7.05), prior subthreshold PTSD (OR = 2.10, 95% CI 1.10-3.99), and deployment TBI (OR = 1.84, 95% CI 1.03-3.28). Controlling for clinical symptoms and TBI, the risk of SI was reduced for those with moderate (OR = 0.50, 95% CI 0.27-0.93) and high psychological resilience scores (OR = 0.25, 95% CI 0.08-0.79) after deployment. Results indicate that even mild symptoms of depression and PTSD may increase the risk of SI. Screening for subthreshold clinical symptoms and TBI while incorporating psychological resilience training would allow for a more multidimensional approach to suicide risk assessment.

Influence of blast exposure on cognitive functioning in combat veterans.

We evaluated the contribution of blast-pressure severity to cognitive functioning beyond posttraumatic stress disorder (PTSD) severity and traumatic brain injury (TBI). Post-9/11 veterans (N = 254, 86.22% male) completed the Wechsler Adult Intelligence Scale (WAIS-IV) and Trail Making Test (TMT). The Clinician-Administered PTSD Scale (CAPS-5), Mid-Atlantic MIRECC Assessment of TBI, and the Salisbury Blast Interview evaluated PTSD diagnosis/severity, deployment TBI history/severity, and blast-exposure history/severity, respectively. Veterans with mild deployment TBI had overall significantly lower T scores on the WAIS-IV Verbal Comprehension Index (d = .13), Working Memory Index (d = .30), and Processing Speed Index (d = .25); the Trail Making Test A (TMT-A; d = .50); and the Trail Making Test B (TMT-B; d = .37). Mild deployment TBI was significantly associated with TMT-A (ΔR² = .05, p < .001) and TMT-B (ΔR² = .03, p = .001) performance. Blast-pressure severity moderated the association between mild deployment TBI and TMT-A (ΔR² = .02, p = .039, B = -2.01). Blast-pressure severity exacerbated the effects of mild TBI on a simple attention task, such that participants with TBI had gradual decrements in attention as blast severity increased. Veterans who incur a TBI and are exposed to blasts during deployment may experience persisting difficulties with cognitive functioning as a result of alterations in basic attention abilities. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Long-term negative emotional outcomes of warzone TBI

Objective Many veterans of the Iraq and Afghanistan Wars have experienced traumatic brain injury (TBI). Although prior work has examined associations between TBI and development of psychiatric syndromes, less is known about associations between TBI and component emotions constituting these syndromes, especially in the long term. The purpose of this study was to examine the long-term emotional consequences of deployment-related TBI. Methods As part of VA Cooperative Studies Program #566, we assessed a sample of n = 456 US Army soldiers prior to an index deployment to Iraq, and again an average of 8.3 years (SD = 2.4 years) after their deployment for a long-term follow-up assessment. In this report, we used adjusted regression analyses to examine the relationship of deployment TBI to depression, anxiety, and stress symptom severity measured at the long-term follow-up assessment. A structured interview was used to determine TBI history; the Depression, Anxiety, and Stress Scale, 21-item version (DASS-21) was used to determine emotional status at the follow-up evaluation. Results Warzone TBI events, particularly when greater than mild in severity, were independently associated with depression, anxiety, and stress severity at long-term follow-up, even after taking into account variance attributable to pre-deployment emotional distress and war-zone stress. Post-hoc analyses did not detect independent associations of either number of events or injury mechanism with outcomes. Conclusions These findings highlight the potentially enduring and multi-faceted emotional effects of deployment TBI, underscoring the need for early assessment of negative affectivity in warzone veterans reporting TBI.

Brain Volume in Veterans: Relationship to Posttraumatic Stress Disorder and Mild Traumatic Brain Injury.

Clarify associations between diagnosis of posttraumatic stress disorder (PTSD) and deployment traumatic brain injury (TBI) on salient regional brain volumes in returning combat veterans. Iraq and Afghanistan era combat veterans, N = 163, 86.5% male. Clinician-administered PTSD Scale (CAPS-5), Mid-Atlantic MIRECC Assessment of TBI (MMA-TBI), magnetic resonance imaging. Hierarchical regression analyses evaluated associations and interactions between current and lifetime PTSD diagnosis, deployment TBI, and bilateral volume of hippocampus, anterior cingulate cortex, amygdala, orbitofrontal cortex, precuneus, and insula. Deployment TBI was associated with lower bilateral hippocampal volume (P = .007-.032) and right medial orbitofrontal cortex volume (P = .006). Neither current nor lifetime PTSD diagnosis was associated with volumetric outcomes beyond covariates and deployment TBI. History of deployment TBI is independently associated with lower volumes in hippocampus and medial orbitofrontal cortex. These results support TBI as a potential contributing factor to consider in reduced cortical volume in PTSD.

Blast Exposure and Risk of Recurrent Occupational Overpressure Exposure Predict Deployment TBIs.

Traumatic brain injury (TBI) has been the leading cause of morbidity and mortality in recent military conflicts and deployment-related TBIs are most commonly caused by blast. However, knowledge of risk factors that increase susceptibility to TBI following an acute, high-level blast is limited. We hypothesized that recurrent occupational overpressure exposure (ROPE) may be one factor that increases susceptibility to mild TBI (mTBI) following blast. Using military occupational specialty as a proxy, we examined the effects of high versus low ROPE on mTBI following blast exposure. Initial analyses included 111,641 active-duty-enlisted U.S. Marines who completed the 2003 or 2008 version of the Post-Deployment Health Assessment. Final analyses examined probable mTBI screens among Marines with at least one qualifying exposure as a function of whether the exposure was a blast and level of ROPE (N=12,929). This study was approved by the Institutional Review Board at the Naval Health Research Center. Blast and ROPE were both independently and jointly associated with a probable mTBI. Marines who experienced a blast (vs other qualifying exposure) and those in high (vs low) risk occupations were 1.07 and 1.23 times more likely to sustain a probable mTBI, respectively. Furthermore, among those who experienced a blast during deployment, those in high-risk occupations were 1.45 times more likely than those in low-risk occupations to sustain a probable mTBI. Blast exposure and ROPE were independently associated with mTBIs, and Marines with both blast exposure during deployment and ROPE were especially likely to sustain an mTBI. This suggests that ROPE heightens the risk of mTBI following blast. Ongoing research is examining the severity, symptomology, and sequelae of TBIs as a function of ROPE.

Behavioral and Health Outcomes Associated With Deployment and Nondeployment Acquisition of Traumatic Brain Injury in Iraq and Afghanistan Veterans

ObjectiveTo characterize behavioral and health outcomes in veterans with traumatic brain injury (TBI) acquired in nondeployment and deployment settings. DesignCross-sectional assessment evaluating TBI acquired during and outside of deployment, mental and behavioral health symptoms, and diagnoses. SettingVeterans Affairs Medical Centers. ParticipantsIraq and Afghanistan veterans who were deployed to a warzone (N=1399). InterventionsNot applicable. Main Outcome MeasuresComprehensive lifetime TBI interview, Structured Clinical Interview for DSM-IV Disorders, Combat Exposure Scale, and behavioral and health measures. ResultsThere was a main effect of deployment TBI on depressive symptoms, posttraumatic stress symptoms, poor sleep quality, substance use, and pain. Veterans with deployment TBI were also more likely to have a diagnosis of bipolar, major depressive, alcohol use, and posttraumatic stress disorders than those who did not have a deployment TBI. ConclusionsTBIs acquired during deployment are associated with different behavioral and health outcomes than TBI acquired in nondeployment environments. The presence of TBI during deployment is associated with poorer behavioral outcomes, as well as a greater lifetime prevalence of behavioral and health problems in contrast to veterans without deployment TBI. These results indicate that problems may persist chronically after a deployment TBI and should be considered when providing care for veterans. Veterans with deployment TBI may require treatment alterations to improve engagement and outcomes.

Fear learning alterations after traumatic brain injury and their role in development of posttraumatic stress symptoms

It is unknown how traumatic brain injury (TBI) increases risk for posttraumatic stress disorder (PTSD). One potential mechanism is via alteration of fear-learning processes that could affect responses to trauma memories and cues. We utilized a prospective, longitudinal design to determine if TBI is associated with altered fear learning and extinction, and if fear processing mediates effects of TBI on PTSD symptom change. Eight hundred fifty two active-duty Marines and Navy Corpsmen were assessed before and after deployment. Assessments included TBI history, PTSD symptoms, combat trauma and deployment stress, and a fear-potentiated startle task of fear acquisition and extinction. Startle response and self-reported expectancy and anxiety served as measures of fear conditioning, and PTSD symptoms were measured with the Clinician-Administered PTSD Scale. Individuals endorsing "multiple hit" exposure (both deployment TBI and a prior TBI) showed the strongest fear acquisition and highest fear expression compared to groups without multiple hits. Extinction did not differ across groups. Endorsing a deployment TBI was associated with higher anxiety to the fear cue compared to those without deployment TBI. The association of deployment TBI with increased postdeployment PTSD symptoms was mediated by postdeployment fear expression when recent prior-TBI exposure was included as a moderator. TBI associations with increased response to threat cues and PTSD symptoms remained when controlling for deployment trauma and postdeployment PTSD diagnosis. Deployment TBI, and multiple-hit TBI in particular, are associated with increases in conditioned fear learning and expression that may contribute to risk for developing PTSD symptoms.