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Primary Objective: The purpose of this study was to examine the relationship between resilience and symptom reporting following mild traumatic brain injury (mTBI). It was hypothesized that, as resilience increases, self-reported symptoms would decrease., Research Design: Cross-sectional design., Methods and Procedures: Participants were 142 US military service members who sustained a mTBI, divided into three resilience groups based on participants' responses on the Response to Stressful Experiences Scale: Moderate (n = 42); High (n = 51); and Very High (n = 49). Participants completed the Neurobehavioral Symptom Inventory (NSI) and PTSD Checklist-Civilian Version (PCL-C) within 12 months following injury., Main Outcomes and Results: There were significant main effects for the NSI total score, cognitive cluster and affective cluster, as well as for the PCL-C total score, avoidance cluster and hyperarousal cluster. Pairwise comparisons revealed that there was a negative relationship between resilience and self-reported symptoms overall. Specifically, participants with higher resilience reported fewer post-concussion and PTSD-related symptoms than participants with lower levels of resilience., Conclusions: These findings underscore the important role that resilience plays in symptom expression in military service members with mTBI and suggest that research on targeted interventions to increase resilience in the acute phase following injury is indicated.

This study evaluated frontal behavioural symptoms, via the FrSBe self-report, in military personnel with and without a history of blast-related mild traumatic brain injury (mild TBI). Prospective observational cohort study of combat-deployed service members leveraging 1-year and 5-year demographic and follow up clinical outcome data. The blast mild TBI group (n = 164) showed greater frontal behavioural symptoms, including clinically elevated apathy, disinhibition, and executive dysfunction, during a 5-year follow-up, compared to a group of combat-deployed controls (n = 107) without mild TBI history or history of blast exposure. We also explored changes inbehaviourall symptoms over a 4-year span, which showed clinically significant increases in disinhibition in the blast mild TBI group, whereas the control group did not show significant increases in symptoms over time. Our findings add to the growing evidence that a proportion of individuals who sustain mild TBI experience persistent behavioural symptoms. We also offer a demonstration of a novel use of the FrSBe as a tool for longitudinal symptom monitoring in a military mild TBI population. [ABSTRACT FROM AUTHOR]

Military service members are at increased risk for mental health issues, and comorbidity with mild traumatic brain injury (mTBI) is common. Largely overlapping symptoms between conditions suggest a shared pathophysiology. The present work investigates the associations among white matter microstructure, psychological functioning, and serum neuroactive steroids that are part of the stress-response system. Diffusion-weighted brain imaging was acquired from 163 participants (with and without military affiliation) and free-water-corrected fractional anisotropy (FAT) was extracted. Associations between serum neurosteroid levels of allopregnanolone (ALLO) and pregnenolone (PREGNE), psychological functioning, and whole-brain white matter microstructure were assessed using regression models. Moderation models tested the effect of mTBI and comorbid post-traumatic stress disorder (PTSD) and mTBI on these associations. ALLO is associated with whole-brain white matter FAT (β = 0.24, t = 3.05, p = 0.006). This association is significantly modulated by PTSD+mTBI comorbidity (β = 0.00, t = 2.50, p = 0.027), although an mTBI diagnosis alone did not significantly impact this association (p = 0.088). There was no significant association between PREGNE and FAT (p = 0.380). Importantly, lower FAT is associated with poor psychological functioning (β = -0.19, t = -2.35, p = 0.020). This study provides novel insight into a potential common pathophysiological mechanism of neurosteroid dysregulation underlying the high risk for mental health issues in military service members. Further, comorbidity of PTSD and mTBI may bring the compensatory effects of the brain's stress response to their limit. Future research is needed to investigate whether neurosteroid regulation may be a promising tool for restoring brain health and improving psychological functioning. [ABSTRACT FROM AUTHOR]

Introduction: Autonomic dysfunction has been implicated as a consequence of traumatic brain injury (TBI). Heart rate variability (HRV) may be a viable measure of autonomic dysfunction that could enhance rehabilitative interventions for individuals with TBI. This pilot study sought to assess the feasibility and validity of using the Zeriscope™ platform system in a real-world clinical setting to measure HRV in active-duty service members with TBI who were participating in an intensive outpatient program. Methods: Twenty-five service members with a history of mild, moderate, or severe TBI were recruited from a military treatment facility. A baseline assessment was conducted in the cardiology clinic where point validity data were obtained by comparing a 5-min recording of a standard 12-lead electrocardiogram (ECG) output against the Zeriscope platform data. Results: Compared with the ECG device, the Zeriscope device had a concordance coefficient (rc) of 0.16, falling below the standard deemed to represent acceptable accuracy in HR measurement (i.e., 0.80). Follow-up analyses excluding outliers did not significantly improve the concordance coefficient to an acceptable standard for the total participant sample. System Usability Survey responses showed that participants rated the Zeriscope system as easy to use and something that most people would learn to use quickly. Conclusions: This study demonstrated promise in ambulatory HRV measurement in a representative military TBI sample. Future research should include further refinement of such ambulatory devices to meet the specifications required for use in a military active-duty TBI population. [ABSTRACT FROM AUTHOR]

To describe associations of demographic, military, and health comorbidity variables between mild traumatic brain injury (mTBI) history and posttraumatic stress disorder (PTSD) status in a sample of Former and current military personnel. Participants recruited and tested at seven VA sites and one military training facility in the LIMBIC-CENC prospective longitudinal study (PLS), which examines the long-term mental health, neurologic, and cognitive outcomes among previously combat-deployed U.S. Service Members and Veterans (SM/Vs). A total of 1,540 SM/Vs with a history of combat exposure. Data were collected between 1/1/2015 through 3/31/2019. Cross-sectional analysis using data collected at enrollment into the longitudinal study cohort examining demographic, military, and health comorbidity variables across PTSD and mTBI subgroups. PTSD Checklist for DSM-5 (PCL-5), mTBI diagnostic status, Patient Health Questionnaire 9-item (PHQ-9), Pittsburgh Sleep Quality Index (PSQI), AUDIT-C, and other self-reported demographic, military, and health comorbidity variables. Ten years following an index date of mTBI exposure or mid-point of military deployment, combat-exposed SM/Vs with both mTBI history and PTSD had the highest rates of depression symptoms, pain, and sleep apnea risk relative to SM/Vs without both of these conditions. SM/Vs with PTSD, irrespective of mTBI history, had high rates of obesity, sleep problems, and pain. The long-term symptom reporting and health comorbidities among SM/Vs with mTBI history and PTSD suggest that ongoing monitoring and intervention is critical for addressing symptoms and improving quality of life. [ABSTRACT FROM AUTHOR]

Combat‐related mild traumatic brain injury (cmTBI) is a leading cause of sustained physical, cognitive, emotional, and behavioral disabilities in Veterans and active‐duty military personnel. Accurate diagnosis of cmTBI is challenging since the symptom spectrum is broad and conventional neuroimaging techniques are insensitive to the underlying neuropathology. The present study developed a novel deep‐learning neural network method, 3D‐MEGNET, and applied it to resting‐state magnetoencephalography (rs‐MEG) source‐magnitude imaging data from 59 symptomatic cmTBI individuals and 42 combat‐deployed healthy controls (HCs). Analytic models of individual frequency bands and all bands together were tested. The All‐frequency model, which combined delta‐theta (1–7 Hz), alpha (8–12 Hz), beta (15–30 Hz), and gamma (30–80 Hz) frequency bands, outperformed models based on individual bands. The optimized 3D‐MEGNET method distinguished cmTBI individuals from HCs with excellent sensitivity (99.9 ± 0.38%) and specificity (98.9 ± 1.54%). Receiver‐operator‐characteristic curve analysis showed that diagnostic accuracy was 0.99. The gamma and delta‐theta band models outperformed alpha and beta band models. Among cmTBI individuals, but not controls, hyper delta‐theta and gamma‐band activity correlated with lower performance on neuropsychological tests, whereas hypo alpha and beta‐band activity also correlated with lower neuropsychological test performance. This study provides an integrated framework for condensing large source‐imaging variable sets into optimal combinations of regions and frequencies with high diagnostic accuracy and cognitive relevance in cmTBI. The all‐frequency model offered more discriminative power than each frequency‐band model alone. This approach offers an effective path for optimal characterization of behaviorally relevant neuroimaging features in neurological and psychiatric disorders. [ABSTRACT FROM AUTHOR]

Mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are common in military populations and share numerous symptoms. Functional graph theory studies demonstrate altered small-world brain networks in mTBI and PTSD, but little is known about structural covariance networks or the potentially distinct topology of mTBI-PTSD comorbidity. The purpose of this study was to compare brain structural covariance networks in healthy active duty military service members (CON) to those with PTSD, mTBI, and mTBI-PTSD. Seventy-six service members (31 CON, 14 PTSD, 12 mTBI, 19 mTBI-PTSD) completed clinical questionnaires and structural magnetic resonance imaging scans. Cortical thickness–derived adjacency matrices were used to determine structural covariance network topologies. Pairwise comparisons for characteristic path length, clustering coefficient, modularity (global), closeness centrality (nodal), and local efficiency were made across a range of network densities (5–35%) using non-parametric permutation tests. All clinical groups showed greater levels of arousal, stress, anxiety, and depression compared with CON. Global network analysis revealed greater clustering and local efficiency in PTSD compared with CON, whereas nodal analysis indicated altered path lengths and closeness centrality in fronto-limbic areas with mTBI-PTSD. Global and nodal graph outcomes suggest distinct pathophysiological manifestations of mTBI, PTSD, and mTBI-PTSD in structural brain networks. Greater network segregation and nodal differences in fronto-limbic areas may be tied to emotional fluctuations. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the associations between resilience, adversity, post-concussion symptoms, and post-traumatic stress symptom reporting after mild traumatic brain injury (mTBI). We hypothesized that resilience would be associated with less symptom reporting, and adversity would be associated with greater symptom reporting. This was a cross-sectional study of retrospective data collected for an ongoing TBI repository. United States military service members who screened positive for mTBI during a primary care visit completed the Trauma History Screen (THS), Connor-Davidson Resilience Scale (CD-RISC), Neurobehavioral Symptom Inventory (NSI), and post-traumatic stress disorder (PTSD) Checklist-Civilian Version (PCL-C). Data collected from February 2015 to August 2016 were used for the present study. Only participants with complete data for the above measures were included, yielding a sample size of 165 participants. Adversity (THS) and resilience (CD-RISC) scores were each correlated significantly with post-concussion (NSI) and traumatic stress (PCL-C) total and subscale scores in the hypothesized direction. Interactions between adversity and resilience were absent for all measures except the NSI sensory subscale. Four traumatic event types were significantly associated positively with most NSI and PCL-C total and subscale scores, but the age at which traumatic events were first experienced showed few and mixed significant associations. In conclusion, resilience and adversity were significantly associated with symptom endorsement after mTBI. Screening for cumulative adversity may identify individuals at greater risk of developing persistent post-concussion symptoms and/or PTSD, and interventions that increase resilience may reduce symptom severity. [ABSTRACT FROM AUTHOR]

The purpose of this study is to examine the clinical utility of the Conners' Continuous Performance Test (CPT-II) as an embedded marker of poor effort in military personnel undergoing neuropsychological evaluations following traumatic brain injury. Participants were 158 U.S. military service members divided into 3 groups on the basis of brain injury severity and performance (pass/fail) on 2 symptom validity tests: Mild Traumatic Brain Injury (MTBI)-Pass (n = 87), MTBI-Fail (n = 42), and severe traumatic brain injury (STBI)-Pass (n = 29). The MTBI-Fail group performed worse on the majority of CPT-II measures compared with both the MTBI-Pass and STBI-Pass groups. When comparing the MTBI-Fail group and MTBI-Pass groups, the most accurate measure for identifying poor effort was the Commission T score. When selected measures were combined (i.e., Omissions, Commissions, and Perseverations), there was a very small increase in sensitivity (from .26 to .29). When comparing the MTBI-Fail group and STBI-Pass groups, the most accurate measure for identifying poor effort was the Omission and Commissions T score. When selected measures were combined, sensitivity again increased (from .24 to .45). Overall, these results suggest that individual CPT-II measures can be useful for identifying people who are suspected of providing poor effort from those who have provided adequate effort. However, due to low sensitivity and modest negative predictive power values, this measure cannot be used in isolation to detect poor effort, and is largely useful as a test to "rule in," not "rule out" poor effort. [ABSTRACT FROM AUTHOR]

This study compared the neuropsychological outcome in military personnel following mild-to-moderate traumatic brain injury (TBI). Participants were 83 service members divided into three injury severity groups: uncomplicated mild TBI (MTBI; n = 24), complicated MTBI (n = 17), and moderate TBI (n = 42). Participants were evaluated within 6 months following injury (73% within 3 months) using neurocognitive testing and the Personality Assessment Inventory (PAI). There were no significant differences between the three groups on the majority of neurocognitive measures. Similarly, there were no significant differences between the three groups on the majority of PAI clinical scales (all p > .05), with the exception of two scales. The uncomplicated MTBI group had significantly higher scores on the Anxiety-Related Disorders and Aggression scales compared with the complicated MTBI group, but not the moderate TBI group. Overall, these results suggest that within the first 6 months post injury, there were few detectable differences in the neuropsychological outcome following uncomplicated MTBI, complicated MTBI, or moderate TBI in this military sample. [ABSTRACT FROM AUTHOR]