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).

Internalizing and externalizing comorbidity and symptom burden in a VA ADHD specialty evaluation clinic

The purpose of this study was to evaluate psychiatric diagnosis and symptom comorbidity in veterans diagnosed with attention-deficit/hyperactivity disorder (ADHD). Study design was retrospective chart review from an ADHD evaluation clinic at a Veterans Affairs hospital. Participants were 227 military veterans who completed a standardized ADHD assessment and produced valid Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) profiles. There were no differences in rates of internalizing or externalizing psychiatric conditions diagnosed in inattentive compared to combined ADHD presentations. However, compared to a subsample with no psychiatric diagnoses, individuals diagnosed with ADHD endorsed significantly more internalizing symptom burden, with combined ADHD veterans also endorsing significantly greater levels of negative emotions and neuroticism. Base rates of comorbid classes of psychiatric diagnoses were not increased in individuals with ADHD, though higher rates of trauma disorders were seen in the combined group compared to the inattentive group. Multivariate base rates of MMPI-2-RF Restructured Clinical scales across various subgroups are presented. There was evidence for differential phenotypes of psychiatric symptoms across ADHD presentations in clinically referred veterans, predominantly related to higher rates of internalizing symptoms.

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.

Research Letter: Blast Exposure and Brain Volume

OBJECTIVE

To determine whether blast exposure is associated with brain volume beyond posttraumatic stress disorder (PTSD) diagnosis and history of traumatic brain injury (TBI).

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

One hundred sixty-three Iraq and Afghanistan combat veterans, 86.5% male, and 68.10% with a history of blast exposure. Individuals with a history of moderate to severe TBI were excluded.

MAIN MEASURES

Clinician-Administered PTSD Scale (CAPS-5), Mid-Atlantic MIRECC Assessment of TBI (MMA-TBI), Salisbury Blast Interview (SBI), and magnetic resonance imaging. Maximum blast pressure experienced from a blast event represented blast severity.

METHODS

Hierarchical regression analysis evaluated effects of maximum pressure experienced from a blast event on bilateral volume of hippocampus, anterior cingulate cortex, amygdala, orbitofrontal cortex, precuneus, and insula. All analyses adjusted for effects of current and lifetime PTSD diagnosis, and a history of deployment mild TBI.

RESULTS

Maximum blast pressure experienced was significantly associated with lower bilateral hippocampal volume (left: ΔR2 = 0.032, P < .001; right: ΔR2 = 0.030, P < .001) beyond PTSD diagnosis and deployment mild TBI history. Other characteristics of blast exposure (time since most recent exposure, distance from closest blast, and frequency of blast events) were not associated with evaluated volumes.

CONCLUSION

Exposure to a blast is independently associated with hippocampal volume beyond PTSD and mild TBI; however, these effects are small. These results also demonstrate that blast exposure in and of itself may be less consequential than severity of the exposure as measured by the pressure gradient.

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).

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).

Performance validity and symptom validity tests: Are they measuring different constructs?

OBJECTIVE

To evaluate the relationships among performance validity, symptom validity, symptom self-report, and objective cognitive testing.

METHOD

Combat Veterans (N = 338) completed a neurocognitive assessment battery and several self-report symptom measures assessing depression, posttraumatic stress disorder (PTSD) symptoms, sleep quality, pain interference, and neurobehavioral complaints. All participants also completed two performance validity tests (PVTs) and one stand-alone symptom validity test (SVT) along with two embedded SVTs.

RESULTS

Results of an exploratory factor analysis revealed a three-factor solution: performance validity, cognitive performance, and symptom report (SVTs loaded on the third factor). Results of t tests demonstrated that participants who failed PVTs displayed significantly more severe symptoms and significantly worse performance on most measures of neurocognitive functioning compared to those who passed. Participants who failed a stand-alone SVT also reported significantly more severe symptomatology on all symptom report measures, but the pattern of cognitive performance differed based on the selected SVT cutoff. Multiple linear regressions revealed that both SVT and PVT failure explained unique variance in symptom report, but only PVT failure significantly predicted cognitive performance.

CONCLUSIONS

Performance and symptom validity tests measure distinct but related constructs. SVTs and PVTs are significantly related to both cognitive performance and symptom report; however, the relationship between symptom validity and symptom report is strongest. SVTs are also differentially related to cognitive performance and symptom report based on the utilized cutoff score. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Sleep moderates symptom experience in combat veterans

BACKGROUND

Though sleep disturbance has shown to negatively affect outcomes related to post-deployment conditions, it is unclear whether and how sleep disturbance affects mental health symptoms beyond these conditions. We evaluated the independent and moderating effects of sleep quality on posttraumatic stress disorder (PTSD), depressive, and neurobehavioral symptoms beyond mild traumatic brain injury (TBI) and PTSD diagnosis.

METHODS

Participants were 274 US combat veterans who deployed after 9/11. All completed diagnostic TBI and PTSD interviews and self-report measures of sleep quality, as well as PTSD, depressive, and neurobehavioral symptoms. Only those who passed symptom validity were included in analyses. Hierarchical regression evaluated the contribution of sleep quality to outcomes beyond PTSD and mild TBI. Moderation analyses evaluated interactions between mild TBI, PTSD, and sleep quality on symptom outcomes.

RESULTS

Mild TBI was only significantly associated with PTSD (p = .006) and neurobehavioral (p = .003) symptoms. PTSD diagnosis was associated with PTSD (p < .001), depressive (p < .001), and neurobehavioral symptoms (p < .001) beyond mild TBI. Sleep quality explained additional significant variance in all three outcome measures (p < .001), and also significantly moderated the effects of PTSD diagnosis on neurobehavioral symptoms (ΔR² = .01, p = .023).

LIMITATIONS

Sleep was evaluated subjectively and therefore must be interpreted in this context.

CONCLUSIONS

These results provide support that sleep quality is an independent contributing factor to health outcomes in post-deployment veterans and should be considered in etiology of complaints.

Distress Tolerance and Symptom Severity as Mediators of Symptom Validity Failure in Veterans With PTSD

OBJECTIVE

Performance validity tests (PVTs) and symptom validity tests (SVTs) are necessary in clinical and research contexts. The extent to which psychiatric distress contributes to failure on these tests is unclear. The authors hypothesized that the relation between posttraumatic stress disorder (PTSD) and validity would be serially mediated by distress tolerance and symptom severity.

METHODS

Participants included 306 veterans, 110 of whom met full criteria for current PTSD. PVTs included the Medical Symptom Validity Test (MSVT) and b Test. The Structured Inventory of Malingered Symptomatology (SIMS) was used to measure symptom validity.

RESULTS

MSVT failure was significantly and directly associated with PTSD severity (B=0.05, CI=0.01, 0.08) but not distress tolerance or PTSD diagnosis. b Test performance was not significantly related to any variable. SIMS failure was significantly associated with PTSD diagnosis (B=0.71, CI=0.05, 1.37), distress tolerance (B=-0.04, CI=-0.07, -0.01), and symptom severity (B=0.07, CI=0.04, 0.09). The serial mediation model significantly predicted all SIMS subscales.

CONCLUSIONS

PTSD severity was associated with failing a memory-based PVT but not an attention-based PVT. Neither PVT was associated with distress tolerance or PTSD diagnosis. SVT failure was associated with PTSD diagnosis, poor distress tolerance, and high symptomatology. For veterans with PTSD, difficulty managing negative emotional states may contribute to symptom overreporting. This may reflect exaggeration or an inability to tolerate stronger negative affect, rather than a "cry for help."

Initial Validation of the Mid-Atlantic Mental Illness Research, Education, and Clinical Center Assessment of Traumatic Brain Injury

With the increasing prevalence of traumatic brain injury (TBI), the need for reliable and valid methods to evaluate TBI has also increased. The purpose of this study was to establish the validity and reliability of a new comprehensive assessment of TBI, the Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MIRECC) Assessment of TBI (MMA-TBI). The participants in this study were post-deployment, combat exposed veterans. First, MMA-TBI outcomes were compared with those of independently conducted clinical TBI assessments. Next, MMA-TBI outcomes were compared with those of a different validated TBI measure (the Ohio State University TBI Identification method [OSU-TBI-ID]). Next, four TBI subject matter experts independently evaluated 64 potential TBI events based on both clinical judgment and Veterans Administration/Department of Defense (VA/DoD) Clinical Practice Guidelines. Results of the MMA-TBI algorithm (based on VA/DoD clinical guideline) were compared with those of the subject matter experts. Diagnostic correspondence with independently conducted expert clinical evaluation was 96% for lifetime TBI and 92% for deployment-acquired TBI. Consistency between the MMA-TBI and the OSU-TBI-ID was high (κ = 0.90; Kendall Tau = 0.94). Comparison of MMA-TBI algorithm results with those of subject matter experts was high (κ = 0.97-1.00). The MMA-TBI is the first TBI interview to be validated against an independently conducted clinical TBI assessment. Overall, results demonstrate the MMA-TBI is a highly valid and reliable instrument for determining TBI based on VA/DoD clinical guidelines. These results support the need for application of standardized TBI criteria across all diagnostic contexts.

Test of Premorbid Functioning: You're Doing It Wrong, but Does It Matter?

OBJECTIVE

Clarify procedures to correctly score Test of Premorbid Functioning (TOPF) and assess the accuracy of TOPF scores in the estimation of premorbid intellectual functioning.

METHOD

In this cross-sectional study, post-9/11 veterans (N = 233, 84.12% male) completed the TOPF, the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV), and performance validity measures.

RESULTS

All TOPF scores were significantly correlated with WAIS-IV FSIQ scores (range r = 0.56-.73). The degree of discrepancy between TOPF scores and FSIQ varied with 10%-17% of TOPF scores deviating from FSIQ scores by one SD or more.

CONCLUSIONS

Proper TOPF scoring procedures are presented. The TOPF Actual and Predicted scores were related to FSIQ. However, a higher percentage of Actual and Predicted scores were discrepant from FSIQ compared with the other three TOPF estimates, arguing against their use as independent premorbid estimates. Use of the TOPF as was designed is recommended.

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

OBJECTIVE

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.

METHOD

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.

RESULTS

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.

CONCLUSIONS

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).

Sequelae of Blast Events in Iraq and Afghanistan War Veterans using the Salisbury Blast Interview: A CENC Study

Objective: To comprehensively characterize blast exposure across the lifespan and relationship to TBI.Participants: Post-deployment veterans and service members (N = 287).Design: Prospective cohort recruitment.Main Measures: Salisbury Blast Interview (SBI).Results: 94.4% of participants reported at least one blast event, 75% reported a pressure gradient during a blast event. Participants reported an average of 337.7 (SD = 984.0) blast events (range 0-4857), 64.8% occurring during combat. Across participants, 19.7% reported experiencing a traumatic brain injury (TBI) during a blast event. Subjective ratings of blast characteristics (wind, debris, ground shaking, pressure, temperature, sound) were significantly higher when TBI was experienced and significantly lower when behind cover. Pressure had the strongest association with resulting TBI (AUC = 0.751). Pressure rating of 3 had the best sensitivity (.54)/specificity (.87) with TBI. Logistic regression demonstrated pressure, temperature and distance were the best predictors of TBI, and pressure was the best predictor of primary blast TBI.Conclusion: Results demonstrate the ubiquitous nature of blast events and provide insight into blast characteristics most associated with resulting TBI (pressure, temperature, distance). The SBI provides comprehensive characterization of blast events across the lifespan including the environment, protective factors, blast characteristics and estimates of distance and munition.

Effects of Distraction on Performance Validity: A Pilot Study with Veterans

OBJECTIVE

The purpose of this experimental pilot study was to evaluate whether distraction can affect results of performance validity testing.

METHOD

Thirty-three veterans who have served in the US military since 09/11/2001 (Mage = 38.60, SD = 10.85 years) completed the Test of Memory Malingering (TOMM), Trail Making Test, and Medical Symptom Validity Test (MSVT). Subjects were randomly assigned to complete the MSVT in one of three experimental conditions: standard administration, while performing serial 2 s (Cognitive Distraction), and while submerging a hand in ice water (Physical Distraction).

RESULTS

All participants included in primary analyses passed the TOMM (n = 30). Physical distraction did not affect performance on the MSVT. Cognitive distraction negatively affected MSVT performance.

CONCLUSIONS

Cognitive distraction can substantially affect MSVT performance in a subgroup of individuals. Physical distraction did not significantly affect MSVT performance.

Digit Span embedded validity indicators in neurologically-intact veterans

Objective: Embedded validity measures are useful in neuropsychological evaluations but should be updated with new test versions and validated across various samples. This study evaluated Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV) Digit Span validity indicators in post-deployment veterans.Method: Neurologically-intact veterans completed structured diagnostic interviews, the WAIS-IV, the Medical Symptom Validity Test (MSVT), and the b Test as part of a larger study. The Noncredible group included individuals who failed either the MSVT or the b Test. Of the total sample (N = 275), 21.09% failed the MSVT and/or b Test. Diagnostic accuracy was calculated predicting group status across cutoff scores on two Digit Span variables, four Reliable Digit Span (RDS) variables, and two Vocabulary minus Digit Span variables.Results: Digit Span age-corrected scaled score (ACSS) had the highest AUC (.648) of all measures assessed; however, sensitivity at the best cutoff of <7 was only 0.17. Of RDS measures, the Working Memory RDS resulted in the highest AUC (.629), but Enhanced RDS and Alternate RDS produced the highest sensitivities (0.22). Overall, cutoff scores were consistent with other studies, but sensitivities were lower. Vocabulary minus Digit Span measures were not significant.Conclusions: Digit Span ACSS was the strongest predictor of noncredible performance, and outperformed traditional RDS variants. Sensitivity across all validity indicators was low in this research sample, though cutoff scores were congruent with previous research. Although embedded Digit Span validity indicators may be useful, they are not sufficient to replace standalone performance validity tests.

Relationship between traumatic brain injury history and recent suicidal ideation in Iraq/Afghanistan-era veterans

This study evaluated whether a history of traumatic brain injury (TBI) was associated with increased risk for recent suicidal ideation (SI) after accounting for demographics, depression, posttraumatic stress disorder (PTSD), and sleep quality. In terms of increased risk, we hypothesized that a history of lifetime TBI would be associated with increased recent SI when compared with no history of TBI; multiple injuries were also evaluated. The sample included Iraq and Afghanistan war-era veterans (n = 838) who served in the United States military since 9/2001 and completed a structured TBI interview. Approximately 50% reported a lifetime history of at least 1 TBI, and 17.9% met criteria for current major depressive disorder (MDD). SI over the past week per the Beck Scale for Suicide Ideation was the primary outcome. Demographics, current MDD and posttraumatic stress disorder (PTSD) per Structured Clinical Interview of DSM-IV Axis I Disorders, sleep quality per Pittsburgh Sleep Quality Index, and TBI history per structured interview were included in all statistical models. Current depression and poor sleep quality were consistently associated with recent SI. A history of any TBI history across the life span was not associated with increased recent SI (OR = 1.35, 95% CI [0.83, 2.19]). However, a history of multiple TBIs compared with no history of TBI was associated with increased recent SI (OR = 1.76, 95% CI [1.01, 3.06]). Results support the assertion than an accumulation of injuries amplifies risk. Severity of injury and deployment injuries were not significant factors. Among those with a history of 1 TBI, sleep, and depression, which may also be injury sequelae, may be salient treatment targets. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Longitudinal changes in neuroimaging and neuropsychiatric status of post-deployment veterans: a CENC pilot study

PRIMARY OBJECTIVE

The purpose of this study was to evaluate preliminary data on longitudinal changes in psychiatric, neurobehavioural, and neuroimaging findings in Iraq and Afghanistan combat veterans following blast exposure.

RESEARCH DESIGN

Longitudinal observational analysis.

METHODS AND PROCEDURES

Participants were invited to participate in two research projects approximately 7 years apart. For each project, veterans completed the Structured Clinical Interview for DSM-IV Disorders and/or the Clinician-Administered PTSD Scale, Neurobehavioral Symptom Inventory, and magnetic resonance imaging (MRI).

MAIN OUTCOMES AND RESULTS

Chi-squared tests indicated no significant changes in current psychiatric diagnoses, traumatic brain injury (TBI) history, or blast exposure history between assessment visits. Wilcoxon signed-rank tests indicated significant increases in median neurobehavioural symptoms, total number of white matter hyperintensities (WMH), and total WMH volume between assessment visits. Spearman rank correlations indicated no significant associations between change in psychiatric diagnoses, TBI history, blast exposure history, or neurobehavioural symptoms and change in WMH.

CONCLUSION

MRI WMH changes were not associated with changes in psychiatric diagnoses or symptom burden, but were associated with severity of blast exposure. Future, larger studies might further evaluate presence and aetiology of long-term neuropsychiatric symptoms and MRI findings in blast-exposed populations.

Increased Small-World Network Topology Following Deployment-Acquired Traumatic Brain Injury Associated with the Development of Post-Traumatic Stress Disorder

Cross-sectional and longitudinal studies in active duty and veteran cohorts have both demonstrated that deployment-acquired traumatic brain injury (TBI) is an independent risk factor for developing post-traumatic stress disorder (PTSD), beyond confounds such as combat exposure, physical injury, predeployment TBI, and pre-deployment psychiatric symptoms. This study investigated how resting-state brain networks differ between individuals who developed PTSD and those who did not following deployment-acquired TBI. Participants included postdeployment veterans with deployment-acquired TBI history both with and without current PTSD diagnosis. Graph metrics, including small-worldness, clustering coefficient, and modularity, were calculated from individually constructed whole-brain networks based on 5-min eyes-open resting-state magnetoencephalography (MEG) recordings. Analyses were adjusted for age and premorbid IQ. Results demonstrated that participants with current PTSD displayed higher levels of small-worldness, F(1,12) = 5.364, p < 0.039, partial eta squared = 0.309, and Cohen's d = 0.972, and clustering coefficient, F(1, 12) = 12.204, p < 0.004, partial eta squared = 0.504, and Cohen's d = 0.905, than participants without current PTSD. There were no between-group differences in modularity or the number of modules present. These findings are consistent with a hyperconnectivity hypothesis of the effect of TBI history on functional networks rather than a disconnection hypothesis, demonstrating increased levels of clustering coefficient rather than a decrease as might be expected; however, these results do not account for potential changes in brain structure. These results demonstrate the potential pathological sequelae of changes in functional brain networks following deployment-acquired TBI and represent potential neurobiological changes associated with deployment-acquired TBI that may increase the risk of subsequently developing PTSD.

The Post-Deployment Mental Health (PDMH) study and repository: A multi-site study of US Afghanistan and Iraq era veterans

The United States (US) Department of Veterans Affairs (VA) Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MIRECC) Post-Deployment Mental Health (PDMH) multi-site study examines post-deployment mental health in US military Afghanistan/Iraq-era veterans. The study includes the comprehensive behavioral health characterization of over 3600 study participants and the genetic, metabolomic, neurocognitive, and neuroimaging data for many of the participants. The study design also incorporates an infrastructure for a data repository to re-contact participants for follow-up studies. The overwhelming majority (94%) of participants consented to be re-contacted for future studies, and our recently completed feasibility study indicates that 73-83% of these participants could be reached successfully for enrollment into longitudinal follow-up investigations. Longitudinal concurrent cohort follow-up studies will be conducted (5-10+ years post-baseline) to examine predictors of illness chronicity, resilience, recovery, functional outcome, and other variables, and will include neuroimaging, genetic/epigenetic, serum biomarker, and neurocognitive studies, among others. To date, the PDMH study has generated more than 35 publications from the baseline data and the repository has been leveraged in over 20 publications from follow-up studies drawing from this cohort. Limitations that may affect data collection for a longitudinal follow-up study are also presented.

Contrasting Effects of Posttraumatic Stress Disorder and Mild Traumatic Brain Injury on the Whole-Brain Resting-State Network: A Magnetoencephalography Study

The aim of this study was to evaluate alterations in whole-brain resting-state networks associated with posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI). Networks were constructed from locations of peak statistical power on an individual basis from magnetoencephalography (MEG) source series data by applying the weighted phase lag index and surrogate data thresholding procedures. Networks representing activity in the alpha bandwidth as well as wideband activity (DC-80 Hz) were created. Statistical comparisons were adjusted for age and education level. Alpha network results demonstrate reductions in network structure associated with PTSD, but no differences associated with mTBI. Wideband network results demonstrate a shift in connectivity from the alpha to theta bandwidth in both PTSD and mTBI. Also, contrasting alterations in network structure are noted, with increased randomness associated with PTSD and increased structure associated with mTBI. These results demonstrate the potential of the analysis of MEG resting-state networks to differentiate two highly comorbid conditions. The importance of the alpha bandwidth to resting-state connectivity is also highlighted, while demonstrating the necessity of considering activity in other bandwidths during network construction.

Examining the factor structure of the Connor-Davidson Resilience Scale (CD-RISC) in a post-9/11 U.S. military veteran sample

The present study examined the structural validity of the 25-item Connor-Davidson Resilience Scale (CD-RISC) in a large sample of U.S. veterans with military service since September 11, 2001. Participants (N = 1,981) completed the 25-item CD-RISC, a structured clinical interview and a self-report questionnaire assessing psychiatric symptoms. The study sample was randomly divided into two subsamples: an initial sample (Sample 1: n = 990) and a replication sample (Sample 2: n = 991). Findings derived from exploratory factor analysis (EFA) did not support the five-factor analytic structure as initially suggested in Connor and Davidson's instrument validation study. Although parallel analyses indicated a two-factor structural model, we tested one to six factor solutions for best model fit using confirmatory factor analysis. Results supported a two-factor model of resilience, composed of adaptability- (8 items) and self-efficacy-themed (6 items) items; however, only the adaptability-themed factor was found to be consistent with our view of resilience-a factor of protection against the development of psychopathology following trauma exposure. The adaptability-themed factor may be a useful measure of resilience for post-9/11 U.S. military veterans.