Considerations for the assessment of blast exposure in service members and veterans.

Introduction: Blast exposure is an increasingly present occupational hazard for military service members, particularly in modern warfare scenarios. The study of blast exposure in humans is limited by the lack of a consensus definition for blast exposure and considerable variability in measurement. Research has clearly demonstrated a robust and reliable effect of blast exposure on brain structure and function in the absence of other injury mechanisms. However, the exact mechanisms underlying these outcomes remain unclear. Despite clear contributions from preclinical studies, this knowledge has been slow to translate to clinical applications. The present manuscript empirically demonstrates the consequences of variability in measurement and definition across studies through a re-analysis of previously published data from the Chronic Effects of Neurotrauma Study 34. Methods: Definitions of blast exposure used in prior work were examined including Blast TBI, Primary Blast TBI, Pressure Severity, Distance, and Frequency of Exposure. Outcomes included both symptom report and cognitive testing. Results: Results demonstrate significant differences in outcomes based on the definition of blast exposure used. In some cases the same definition was strongly related to one type of outcome, but unrelated to another. Discussion: The implications of these results for the study of blast exposure are discussed and potential actions to address the major limitations in the field are recommended. These include the development of a consensus definition of blast exposure, further refinement of the assessment of blast exposure, continued work to identify relevant mechanisms leading to long-term negative outcomes in humans, and improved education efforts.

Influence of affective instability on suicidal ideation beyond traumatic brain injury and posttraumatic stress disorder in veterans.

OBJECTIVE: Mild traumatic brain injury (TBI) is associated with long-term consequences, including greater risk for posttraumatic stress disorder (PTSD) and suicidal ideation. Affective instability is also independently related to PTSD and suicidality, which may explain why some individuals continue to experience chronic psychiatric complaints following mild TBI. The purpose of the present study was to evaluate affective instability as a key factor for PTSD and suicidal ideation among Veterans with and without TBI. METHOD: Participants (N = 299 Veterans; 86.96% male) completed the Personality Assessment Inventory (PAI) and structured clinical interviews for TBI and psychiatric diagnoses. Hierarchical linear regression was used to evaluate main and interaction effects. RESULTS: There were no significant differences in affective instability (p = 0.140) or suicidal ideation (p = 0.453) between Veterans with or without TBI. Individuals with TBI were more likely to have a PTSD diagnosis (p = 0.001). Analyses evaluating PTSD diagnosis as an outcome indicated a main effect of affective instability (p < 0.001), but not TBI (p = 0.619). Analyses evaluating suicidal ideation as an outcome demonstrated an interaction effect between PTSD and affective instability beyond the effects of TBI (p = 0.034). CONCLUSIONS: Severe Affective instability appears to be a key factor in suicidal ideation among Veterans beyond TBI or PTSD history. PTSD was more strongly associated with suicidality at lower and moderate levels of affective instability. At severe levels of affective instability, however, Veterans with and without PTSD experienced suicidal ideation at similar rates. Findings suggests that high levels of affective instability not better explained by other psychiatric conditions confers similar suicidality risk to that of PTSD in a Veteran population.

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.

Use of magnetic source imaging to assess recovery after severe traumatic brain injury-an MEG pilot study.

Rationale: Severe TBI (sTBI) is a devastating neurological injury that comprises a significant global trauma burden. Early comprehensive neurocritical care and rehabilitation improve outcomes for such patients, although better diagnostic and prognostic tools are necessary to guide personalized treatment plans. Methods: In this study, we explored the feasibility of conducting resting state magnetoencephalography (MEG) in a case series of sTBI patients acutely after injury (~7 days), and then about 1.5 and 8 months after injury. Synthetic aperture magnetometry (SAM) was utilized to localize source power in the canonical frequency bands of delta, theta, alpha, beta, and gamma, as well as DC-80 Hz. Results: At the first scan, SAM source maps revealed zones of hypofunction, islands of preserved activity, and hemispheric asymmetry across bandwidths, with markedly reduced power on the side of injury for each patient. GCS scores improved at scan 2 and by scan 3 the patients were ambulatory. The SAM maps for scans 2 and 3 varied, with most patients showing increasing power over time, especially in gamma, but a continued reduction in power in damaged areas and hemispheric asymmetry and/or relative diminishment in power at the site of injury. At the group level for scan 1, there was a large excess of neural generators operating within the delta band relative to control participants, while the number of neural generators for beta and gamma were significantly reduced. At scan 2 there was increased beta power relative to controls. At scan 3 there was increased group-wise delta power in comparison to controls. Conclusion: In summary, this pilot study shows that MEG can be safely used to monitor and track the recovery of brain function in patients with severe TBI as well as to identify patient-specific regions of decreased or altered brain function. Such MEG maps of brain function may be used in the future to tailor patient-specific rehabilitation plans to target regions of altered spectral power with neurostimulation and other treatments.

Subjective cognitive complaints and objective cognitive functioning in combat veterans: Effects of PTSD and deployment mild TBI.

OBJECTIVES: (1) Examine the relationship between subjective cognitive complaints and objective cognitive functioning in combat veterans; and (2) evaluate conditional effects of posttraumatic stress disorder (PTSD) and deployment-related mild traumatic brain injury (TBI) within that relationship. METHOD: Combat veterans (N = 225, 86.22% male) completed a lifetime TBI interview, a structured interview assessing PTSD symptoms, a neuropsychological assessment battery, and a self-report measure of cognitive symptoms. RESULTS: All correlations between subjective cognitive complaints and objective cognitive measures were not statistically significant. Hierarchical linear regression indicated that cognitive performance was not significantly related to cognitive complaints, but both PTSD diagnosis and history of deployment mild TBI explained a significant amount of unique variance in self-reported cognitive symptoms. Interactions between the studied variables were not significant. CONCLUSIONS: PTSD and history of deployment mild TBI were uniquely related to cognitive complaints, but cognitive test performance was not. No confounding effects of PTSD or deployment mild TBI were observed in the relationship between cognitive performance and cognitive complaints. This provides support that symptom distress may be a better explanatory factor for perception of lower cognitive functioning than actual cognitive performance.

Time doesn't heal all: PTSD symptoms exacerbate the relationship between age and pain intensity.

Objective: Posttraumatic stress disorder (PTSD) symptoms and pain interfere with daily functioning and quality of life for many combat Veterans. As individuals age, pain symptoms tend to increase whereas PTSD symptoms tend to decrease. PTSD symptoms exacerbate pain, but the nature of this relationship across the aging process is unclear. The purpose of this study was to determine how PTSD symptoms affect the association between age and pain intensity. Methods: Participants in this cross-sectional study included 450 Veterans (80% male) who served after September 11, 2001. PTSD and pain intensity ratings were assessed by the PTSD Checklist for DSM-5 (PCL-5) and the Brief Pain Inventory (BPI), respectively. Hierarchical multiple linear regression evaluated main and interaction effects between age, PTSD symptoms, and pain intensity. Results: Age (B = 0.04, p < 0.001) and PTSD symptoms (B = 0.05, p < 0.001) were positively associated with pain intensity. Age and PTSD symptoms were inversely correlated (r = -0.16, p < 0.001). PTSD symptoms exacerbated the relationship between age and pain intensity (ΔR2 = 0.01, p = 0.036). Specifically, when greater PTSD symptoms were reported at older ages, pain intensity was significantly higher. Conclusion: Results of these analyses suggests that age is important when considering the effects of PTSD symptoms on pain intensity ratings. Specifically, pain intensity ratings are higher in older Veterans with PTSD symptoms. These findings underscore the importance for clinical providers to evaluate trauma history and PTSD symptoms in older Veterans reporting pain symptoms.

Symptom validity indices in the Posttraumatic Stress Disorder Checklist for DSM-5.

The use of symptom validity tests (SVTs) is standard practice in psychodiagnostic assessments. Embedded measures are indices within self-report measures. To date, no embedded SVTs have been identified in the Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5). This research aimed to develop and validate PCL-5 SVTs in two samples of veterans. Participants completed one of two prospective research studies that included cognitive and psychological tests. Participants in Study 1 were veterans (N = 464) who served following the September 11, 2001, terrorist attacks; participants in Study 2 were veterans or service members (N = 338) who had been deployed to Iraq and/or Afghanistan. Both studies included the PCL-5 and the Structured Inventory of Malingered Symptomatology (SIMS), the latter of which served as the criterion for identifying PCL-5 SVTs. For Study 1, two separate SVTs were developed: the PCL-5 Symptom Severity scale (PSS), based on the PCL-5 total score, and the PCL-5 Rare Items scale (PRI), based on PCL-5 items infrequently endorsed at the highest item ratings. At the most conservative SIMS cutoff score, the PSS achieved excellent discrimination for both the Study 1, AUC = .840, and Study 2 samples, AUC = .858, with specific cutoff scores of ≥ 51 and ≥ 56 maximizing sensitivity while maintaining a specificity of .90. The PRI achieved good discrimination, AUCs = .760 and.726, respectively, with a cutoff score of 2 or higher indicated by both studies. The results of these two studies provide provisional support for these two embedded SVTs in the PCL-5.

Distress tolerance mitigates effects of posttraumatic stress, traumatic brain injury, and blast exposure on psychiatric and health outcomes.

BACKGROUND: Exposure to blasts is common among service members and history of these exposures has been associated with chronic psychiatric and health outcomes. Evidence suggests that distress tolerance (DT) may moderate this relationship and be a valuable treatment target in this population. The purpose of this manuscript was to evaluate DT as a modifying factor in the association between posttraumatic stress disorder (PTSD), mild traumatic brain injury (TBI), blast exposure, and functional indicators. METHOD: Participants were 275 (86.55% male) combat veterans who served in Iraq or Afghanistan after September 11, 2001. Clinical interviews for PTSD diagnosis, TBI history, and blast exposure were administered, and participants completed self-report questionnaires (DT, PTSD symptom severity, depressive symptom severity, neurobehavioral symptom severity, sleep quality, pain interference, and quality of life). RESULTS: DT was significantly associated with all functional indicators beyond PTSD diagnosis, mild TBI, and blast severity. There were significant interaction effects between DT and PTSD diagnosis for posttraumatic stress symptom severity, sleep quality, and quality of life. Specifically, there were significant differences in these reported functional indicators between individuals with and without a PTSD diagnosis as DT increases, such that reported symptoms were lower (quality of life better) for individuals without PTSD as DT improved. CONCLUSION: Our results demonstrate that DT might be a key factor in postdeployment function for military service members. Treatments targeting DT may be particularly effective in individuals who attribute psychiatric symptoms to history of blast exposure. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Validation of Military Occupational Specialty as a Proxy for Blast Exposure Using the Salisbury Blast Interview.

Abstract Evaluating large data sets precludes the ability to directly measure individual experiences, instead relying on proxies to infer certain constructs. Blast exposure is a construct of study currently in its infancy, resulting in diverse definitions and measurements across studies. The purpose of the present study was to validate military occupational specialty (MOS) as a proxy for blast exposure in combat veterans. A total of 256 veterans (86.33% male) completed the Salisbury Blast Interview (SBI) and Mid-Atlantic Mental Illness Research Education and Clinical Center (MIRECC) Assessment of Traumatic Brain Injury (MMA-TBI). MOS was collected through record review and categorized into low and high risk for blast exposure. Chi-square analyses and t tests compared SBI metrics between MOS categories. Receiver operating characteristic (ROC) analyses evaluated the diagnostic accuracy of MOS category in determining blast exposure severity. Veterans in high-risk MOS were more likely to have experienced blast and deployment TBI (ps < 0.001) than were those in low-risk MOS. ROC analyses indicated good specificity (81.29-88.00) for blast and deployment TBI outcomes, suggesting that low-risk MOS is generally associated with an absence of blast and deployment TBI outcomes. Sensitivity was low (36.46-51.14), indicating that MOS risk level was not a good predictor of the presence of these outcomes. Results demonstrate that high-risk MOSs will identify individuals with blast exposure and deployment TBI history whereas low-risk MOSs will capture a highly variable group. Accuracy of MOS categorization was not acceptable for diagnostic-level tests; however, results support its use as a screening measure for a history of exposure to blast, use in epidemiological studies, and considerations for military policy.

Validation of the personality assessment inventory (PAI) cognitive bias (CBS) and cognitive bias scale of scales (CB-SOS) in a post-deployment veteran sample.

Objective: The present study evaluated the function of four cognitive, symptom validity scales on the Personality Assessment Inventory (PAI), the Cognitive Bias Scale (CBS) and the Cognitive Bias Scale of Scales (CB-SOS) 1, 2, and 3 in a sample of Veterans who volunteered for a study of neurocognitive functioning. Method: 371 Veterans (88.1% male, 66.1% White) completed a battery including the Miller Forensic Assessment of Symptoms Test (M-FAST), the Word Memory Test (WMT), and the PAI. Independent samples t-tests compared mean differences on cognitive bias scales between valid and invalid groups on the M-FAST and WMT. Area under the curve (AUC), sensitivity, specificity, and hit rate across various scale point-estimates were used to evaluate classification accuracy of the CBS and CB-SOS scales. Results: Group differences were significant with moderate effect sizes for all cognitive bias scales between the WMT-classified groups (d = .52-.55), and large effect sizes between the M-FAST-classified groups (d = 1.27-1.45). AUC effect sizes were moderate across the WMT-classified groups (.650-.676) and large across M-FAST-classified groups (.816-.854). When specificity was set to .90, sensitivity was higher for M-FAST and the CBS performed the best (sensitivity = .42). Conclusion: The CBS and CB-SOS scales seem to better detect symptom invalidity than performance invalidity in Veterans using cutoff scores similar to those found in prior studies with non-Veterans.

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.

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.

Contextual Effects of Traumatic Brain Injury on the Connectome: Differential Effects of Deployment- and Non-Deployment-Acquired Injuries.

OBJECTIVE: To identify differential effects of mild traumatic brain injury (TBI) occurring in a deployment or nondeployment setting on the functional brain connectome. SETTING: Veterans Affairs Medical Center. PARTICIPANTS: In total, 181 combat-exposed veterans of the wars in Iraq and Afghanistan ( n = 74 with deployment-related mild TBI, average time since injury = 11.0 years, SD = 4.1). DESIGN: Cross-sectional observational study. MAIN MEASURES: Mid-Atlantic MIRECC (Mid-Atlantic Mental Illness Research, Education, and Clinical Center) Assessment of TBI, Clinician-Administered PTSD Scale, connectome metrics. RESULTS: Linear regression adjusting for relevant covariates demonstrates a significant ( P < .05 corrected) association between deployment mild TBI with reduced global efficiency (nonstandardized ß = -.011) and degree of the K-core (nonstandardized ß = -.79). Nondeployment mild TBI was significantly associated with a reduced number of modules within the connectome (nonstandardized ß = -2.32). Finally, the interaction between deployment and nondeployment mild TBIs was significantly ( P < .05 corrected) associated with increased mean (nonstandardized ß = 9.92) and mode (nonstandardized ß = 14.02) frequency at which connections occur. CONCLUSIONS: These results demonstrate distinct effects of mild TBI on the functional brain connectome when sustained in a deployment versus nondeployment context. This is consistent with findings demonstrating differential effects in other areas such as psychiatric diagnoses and severity, pain, sleep, and cognitive function. Furthermore, participants were an average of 11 years postinjury, suggesting these represent chronic effects of the injury. Overall, these findings add to the growing body of evidence, suggesting the effects of mild TBI acquired during deployment are different and potentially longer lasting than those of mild TBI acquired in a nondeployment context.

Factors associated with recovery from posttraumatic stress disorder in combat veterans: The role of deployment mild traumatic brain injury (mTBI).

OBJECTIVE: Examine factors associated with recovery from posttraumatic stress disorder (PTSD) and evaluate the role of deployment mild traumatic brain injury (mTBI) in the relationship between PTSD recovery and functional outcomes. METHOD: Post 9/11 combat veterans with lifetime history of PTSD (N = 124, 84.7% male) completed the Mid-Atlantic MIRECC Assessment of Traumatic Brain Injury (MMA-TBI), Salisbury Blast Interview (SBI), Clinician Administered PTSD scale (CAPS-5), cognitive assessment battery, and measures of depression, PTSD symptoms, neurobehavioral symptoms, sleep quality, pain interference, and quality of life. RESULTS: Analyses of variance (ANOVA) results revealed significant differences in most behavioral health outcomes based on PTSD recovery, with participants who have recovered from PTSD showing less severe neurobehavioral and depressive symptoms, better sleep quality, less functional pain interference, and higher quality of life. No differences were found in cognitive functioning between those who have recovered from PTSD and those who have not. History of deployment mTBI did not significantly moderate the relationship between PTSD recovery and most functional and cognitive outcomes with the exception of 2 measures of processing speed. Specifically, among participants with history of deployment mTBI, those who have recovered from PTSD displayed better cognitive functioning than those who have not. Additionally, participants who have not recovered from PTSD had higher levels of blast exposure during military service. CONCLUSIONS: PTSD recovery was associated with better psychological functioning and higher quality of life, but not with objective cognitive functioning. Deployment mTBI history moderated only the relationship between PTSD recovery status and tests of processing speed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Operational Stress Control Service: An Organizational Program to Support Health Care Worker Well-Being.

OBJECTIVE: This manuscript details the methods, outcomes, and lessons learned from a successful multi-dimensional, interdisciplinary, institutional response to HCW well-being during the COVID-19 pandemic. METHODS: Operational Stress Control Service (OSCS) is a model for the prevention and management of stress and trauma implemented within an occupational system. Communication, Employee Wellness, and Intervention were targeted program aspects, adapted from an established US military protocol. RESULTS: Since April 2020, OSCS has received 4660 unique survey responses; reached 1007 employees in-person; informed 125 leadership-hosted videoconferences; and assisted 13 departments with grief and morale-related challenges. CONCLUSIONS: OSCS improved communication across the organization and allowed for rapid deployment of solutions to maintain effective operations. Results highlight the benefit of multiple avenues of frequent, bottom-up, and top-down communication. Creating such services during times of normalcy might be considered in preparation for future crisis.

Symptom burden, validity, and cognitive performance in Iraq and Afghanistan veterans.

INTRODUCTION: The present study evaluates the complex relationships between symptom burden, validity, and cognition in a sample of Iraq and Afghanistan veterans to identify key characteristic symptoms and validity measures driving cognitive performance. We hypothesized that symptom and performance validity would account for poorer outcomes on cognitive performance beyond psychological symptoms. METHODS: Veterans (n = 226) completed a cognitive test battery, Personality Assessment Inventory (PAI), Word Memory Test (WMT), and Miller Forensic Assessment Symptom Test (M-FAST). Partial least squares structural equation modeling (PLS-SEM) modeled the fully-adjusted relationships among PAI subscales, validity, and cognitive performance. RESULTS: 23.45% of participants failed validity indices (19.9% WMT; 7.1% M-FAST). PLS-SEM indicated PAI subscales were not directly associated with performance or symptom validity measures, and there were no direct effects between validity performance and cognitive performance. Several PAI subscales were directly associated with measures of verbal abstraction, visual processing, and verbal learning and memory. CONCLUSION: Contrary to hypotheses, symptom and performance validity did not account for poorer outcomes on cognitive performance beyond symptom burden in the PLS-SEM model. Results highlight the association between psychiatric symptoms and cognitive performance beyond validity status.

Effects of blast exposure on psychiatric and health symptoms in combat veterans.

Blast exposure is common among service members, but the chronic psychiatric effects associated with blast exposure are not well-characterized independent of a resulting mild traumatic brain injury (TBI). This analysis evaluated whether blast exposure severity was independently associated with or exacerbated symptom report beyond posttraumatic stress disorder (PTSD) and mild TBI. Participants were Iraq and Afghanistan combat veterans (N = 275; 86.55% male), 71.27% with history of blast exposure, 29.82% current diagnosis of PTSD, and 45.45% with mild TBI. All participants completed diagnostic interviews for PTSD, lifetime TBI, and lifetime blast exposure. Self-reported psychiatric and health outcomes included posttraumatic stress symptoms, depressive symptoms, neurobehavioral symptoms, sleep quality, pain interference, and quality of life. Blast severity was associated with PTSD (B = 2.00), depressive (B = 0.76), and neurobehavioral (B = 1.69) symptoms beyond PTSD diagnosis and mild TBI history. Further, blast severity accounted entirely (i.e., indirect/mediation effect) for the association between TBI and posttraumatic stress (B = 1.62), depressive (B = 0.61), and neurobehavioral (B = 1.38) symptoms. No interaction effects were present. Exposure to blast is an independent factor influencing psychiatric symptoms in veterans beyond PTSD and mild TBI. Results highlight that blast exposure severity may be a more relevant risk factor than deployment mild TBI in combat veterans and should be considered in the etiology of psychiatric symptom presentation and complaints. Further, severity of psychological distress due to the combat environment may be an explanatory mechanism by which blast exposure mediates the relationship between mild TBI and symptom outcomes.

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.

Self-reported neurobehavioral symptoms in combat veterans: An examination of NSI with mBIAS symptom validity scales and potential effects of psychological distress.

This study evaluated symptom validity scales from the Neurobehavioral Symptom Inventory (NSI) and mild Brain Injury Atypical Symptom Scale (mBIAS) in a sample of 338 combat veterans. Classification statistics were computed using the Structured Inventory of Malingered Symptomatology (SIMS) as the validity criterion. Symptom distress was assessed with the Patient Health Questionnaire-9 and Posttraumatic Stress Disorder (PTSD) Checklist-5. At SIMS > 14, the NSI total score resulted in the highest area under the curve (AUC; .91), followed by Validity-10 (AUC = .88) and mBIAS (AUC = .67). At SIMS > 23, both NSI total and Validity-10 AUCs decreased to .88; in contrast, mBIAS AUC increased to .75. The NSI total score and Validity-10 were interpreted to reflect symptom magnification, whereas the mBIAS may reflect symptom fabrication. There was a subsample with elevated Patient Health Questionnaire-9 (PHQ-9) and PTSD Checklist-5 scores who were significantly distressed but not deemed invalid on the NSI; however, there appears to be an upper threshold on the NSI total score (>69) beyond which nobody produced an invalid score on the SIMS. A recommended approach is provided for using NSI-related validity measures. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Rich Club Characteristics of Alcohol-Naïve Functional Brain Networks Predict Future Drinking Phenotypes in Rhesus Macaques.

Purpose: A fundamental question for Alcohol use disorder (AUD) is how and when naïve brain networks are reorganized in response to alcohol consumption. The current study aimed to determine the progression of alcohol's effect on functional brain networks during transition from the naïve state to chronic consumption. Procedures: Resting-state brain networks of six female rhesus macaque (Macaca mulatta) monkeys were acquired using magnetoencephalography (MEG) prior to alcohol exposure and after free-access to alcohol using a well-established model of chronic heavy alcohol consumption. Functional brain network metrics were derived at each time point. Results: The average connection frequency (p < 0.024) and membership of the Rich Club (p < 0.022) changed significantly over time. Metrics describing network topology remained relatively stable from baseline to free-access drinking. The minimum degree of the Rich Club prior to alcohol exposure was significantly predictive of future free-access drinking (r = -0.88, p < 0.001). Conclusions: Results suggest naïve brain network characteristics may be used to predict future alcohol consumption, and that alcohol consumption alters functional brain networks, shifting hubs and Rich Club membership away from previous regions in a non-systematic manner. Further work to refine these relationships may lead to the identification of a high-risk drinking phenotype.