A Systematic Review and Meta-analysis on PTSD Following TBI Among Military/Veteran and Civilian Populations

Post-Traumatic Stress Disorder Symptoms Are Related to Cognition after Complicated Mild and Moderate Traumatic Brain Injury but Not Severe and Penetrating Traumatic Brain Injury

Although post-traumatic stress disorder (PTSD) has been associated with worse cognitive outcomes after mild traumatic brain injury (TBI), its impact has not been evaluated after more severe TBI. This study aimed to determine whether PTSD symptoms are related to cognition after complicated mild, moderate, severe, and penetrating TBI. Service members (n = 137) with a history of complicated mild/moderate TBI (n = 64) or severe/penetrating TBI (n = 73) were prospectively enrolled from United States Military Treatment Facilities. Participants completed a neuropsychological assessment one year or more post-injury. Six neuropsychological composite scores and an overall test battery mean (OTBM) were considered. Participants were excluded if there was evidence of invalid responding. Hierarchical linear regressions were conducted evaluating neuropsychological performance. The interaction between TBI severity and PTSD Checklist-Civilian version total score was significant for processing speed (β = 0.208, p = 0.034) and delayed memory (β = 0.239, p = 0.021) and trended toward significance for immediate memory (β = 0.190, p = 0.057) and the OTBM (β = 0.181, p = 0.063). For each of these composite scores, the relationship between PTSD symptoms and cognition was stronger in the complicated mild/moderate TBI group than the severe/penetrating TBI group. Within the severe/penetrating TBI group, PTSD symptoms were unrelated to cognitive performance. In contrast, within the complicated mild/moderate TBI group, PTSD symptoms were significantly related to processing speed (R²Δ = 0.077, β = -0.280, p = 0.019), immediate memory (R²Δ = 0.197, β = -0.448, p < 0.001), delayed memory (R²Δ = 0.176, β = -0.423, p < 0.001), executive functioning (R²Δ = 0.100, β = -0.317, p = 0.008), and the OTBM (R²Δ = 0.162, β = -0.405, p < 0.001). The potential impact of PTSD symptoms on cognition, over and above the impact of brain injury alone, should be considered with service members and veterans with a history of complicated mild/moderate TBI. In addition, in research comparing cognitive outcomes between patients with histories of complicated-mild, moderate, severe, and/or penetrating TBI, it will be important to account for PTSD symptoms.

Alzheimer's Disease-Related Dementias Summit 2019: National research priorities for the investigation of traumatic brain injury as a risk factor for Alzheimer's Disease and Related Dementias

TBI is a risk factor for later life dementia. Clinical and preclinical studies have elucidated multiple mechanisms through which TBI may influence or exacerbate multiple pathological processes underlying Alzheimer's Disease and Alzheimer's Disease Related Dementias (AD/ADRD). The National Institutes of Health hosts triennial ADRD Summits to inform a national research agenda, and the 2019 ADRD Summit was the first to highlight 'TBI and AD/ADRD Risk' as an emerging topic in the field. A multidisciplinary committee of TBI researchers with relevant expertise reviewed extant literature, identified research gaps and opportunities, and proposed draft research recommendations at the 2019 ADRD Summit. These research recommendations, further refined after broad stakeholder input at the Summit, cover four overall areas: (1) Encourage crosstalk and interdisciplinary collaboration between TBI and dementia researchers, (2) Establish infrastructure to study TBI as a risk factor for AD/ADRD, (3) Promote basic and clinical research examining the development and progression of TBI AD/ADRD neuropathologies and associated clinical symptoms, and (4) Characterize the clinical phenotype of progressive dementia associated with TBI and develop non-invasive diagnostic approaches. These recommendations recognize a need to strengthen communication and build frameworks to connect the complexity of TBI with rapidly evolving AD/ADRD research. Recommendations acknowledge TBI as a clinically and pathologically heterogeneous disease whose associations with AD/ADRDs remain incompletely understood. The recommendations highlight the scientific advantage of investigating AD/ADRD in the context of a known TBI exposure, the study of which can directly inform on disease mechanisms and treatment targets for AD/ADRDs with shared common pathways.

The Relationship Between Cognitive Functioning and Symptoms of Depression, Anxiety, and Post-Traumatic Stress Disorder in Adults with a Traumatic Brain Injury: a Meta-Analysis

A thorough understanding of the relationship between cognitive test performance and symptoms of depression, anxiety, or post-traumatic stress disorder (PTSD) in people with traumatic brain injury (TBI) is important given the high prevalence of these emotional symptoms following injury. It is also important to understand whether these relationships are affected by TBI severity, and the validity of test performance and symptom report. This meta-analysis was conducted to investigate whether these symptoms are associated with cognitive test performance alterations in adults with a TBI. This meta-analysis was prospectively registered on the PROSPERO International Prospective Register of Systematic Reviews website (registration number: CRD42018089194). The electronic databases Medline, PsycINFO, and CINAHL were searched for journal articles published up until May 2020. In total, 61 studies were included, which enabled calculation of pooled effect sizes for the cognitive domains of immediate memory (verbal and visual), recent memory (verbal and visual), attention, executive function, processing speed, and language. Depression had a small, negative relationship with most cognitive domains. These relationships remained, for the most part, when samples with mild TBI (mTBI)-only were analysed separately, but not for samples with more severe TBI (sTBI)-only. A similar pattern of results was found in the anxiety analysis. PTSD had a small, negative relationship with verbal memory, in samples with mTBI-only. No data were available for the PTSD analysis with sTBI samples. Moderator analyses indicated that the relationships between emotional symptoms and cognitive test performance may be impacted to some degree by exclusion of participants with atypical performance on performance validity tests (PVTs) or symptom validity tests (SVTs), however there were small study numbers and changes in effect size were not statistically significant. These findings are useful in synthesising what is currently known about the relationship between cognitive test performance and emotional symptoms in adults with TBI, demonstrating significant, albeit small, relationships between emotional symptoms and cognitive test performance in multiple domains, in non-military samples. Some of these relationships appeared to be mildly impacted by controlling for performance validity or symptom validity, however this was based on the relatively few studies using validity tests. More research including PVTs and SVTs whilst examining the relationship between emotional symptoms and cognitive outcomes is needed.

Neurobehavioral Symptoms in U.S. Special Operations Forces in Rehabilitation After Traumatic Brain Injury: A TBI Model Systems Study

INTRODUCTION

Special Operations Forces (SOF) personnel are at increased risk for traumatic brain injury (TBI), when compared with conventional forces (CF). Prior studies of TBI in military samples have not typically investigated SOF vs. CF as specific subgroups, despite documented differences in premorbid resilience and post-injury comorbidity burden. The aim of the current study was to compare SOF vs. CF on the presence of neurobehavioral symptoms after TBI, as well as factors influencing perception of symptom intensity.

MATERIALS AND METHODS

This study conducted an analysis of the prospective veterans affairs (VA) TBI Model Systems Cohort, which includes service members and veterans (SM/V) who received inpatient rehabilitation for TBI at one of the five VA Polytrauma Rehabilitation Centers. Of those with known SOF status (N = 342), 129 participants identified as SOF (average age = 43 years, 98% male) and 213 identified as CF (average age = 38.7 years, 91% male). SOF vs. CF were compared on demographics, injury characteristics, and psychological and behavioral health symptoms. These variables were then used to predict neurobehavioral symptom severity in univariable and multivariable analyses.

RESULTS

SOF personnel reported significantly greater posttraumatic stress disorder (PTSD) symptoms but less alcohol and drug use than the CF. SOF also reported greater neurobehavioral symptoms. When examining those with TBIs of all severities, SOF status was not associated with neurobehavioral symptom severity, while race, mechanism of TBI, and PTSD symptoms were. When examining only those with mTBI, SOF status was associated with lower neurobehavioral symptoms, while PTSD severity, white race, and certain mechanisms of injury were associated with greater neurobehavioral symptoms.

CONCLUSIONS

Among those receiving inpatient treatment for TBI, SOF SM/V reported higher neurobehavioral and symptom severity. PTSD was the strongest predictor of neurobehavioral symptoms and should be considered an important treatment target in both SOF and CF with co-morbid PTSD/TBI. A proactive human performance approach towards identification and treatment of psychological and neurobehavioral symptoms is recommended for SOF.

Mental and physical health, and long-term quality of life among service members injured on deployment

Background

More than 52,000 casualties have been documented in post-9/11 conflicts. Service members with extremity injuries (EIs) or traumatic brain injury (TBI) may be at particular risk for long-term deficits in mental and physical health functioning compared with service members with other injuries.

Methods

The present study combined medical records with patient reports of mental health and health-related quality of life (HRQOL) for 2,537 service members injured in overseas contingency operations who participated in the Wounded Warrior Recovery Project. Combined parallel-serial mediation models were tested to examine the pathways through which injury is related to mental and physical health conditions, and long-term HRQOL.

Results

Results revealed that injury was indirectly related to long-term HRQOL via its associations with physical health complications and mental health symptoms. Relative to TBI, EI was associated with a higher likelihood for a postinjury diagnosis for a musculoskeletal condition, which were related to lower levels of later posttraumatic stress disorder (PTSD) symptoms, and higher levels of physical and mental HRQOL. Similarly, EI was related to a lower likelihood for a postinjury PTSD diagnosis, and lower levels of subsequent PTSD symptoms, and therefore higher physical and mental HRQOL relative to those with TBI. Despite this, the prevalence of probable PTSD among those with EI was high (35%). Implications for intervention, rehabilitation, and future research are discussed.

Improvement in executive functioning after Goal-Oriented Attentional Self-Regulation training is associated with reduction in PTSD hyperarousal symptoms among veterans with comorbid PTSD and mild TBI

Goal-Oriented Attentional Self-Regulation (GOALS) is a cognitive rehabilitation training program that combines mindfulness-based attention regulation with individualized goal management strategies to improve functioning in daily life after traumatic brain injury (TBI). While not a specific target of GOALS training, previous research has indicated improvements in emotional functioning following GOALS training, specifically symptoms related to depression and posttraumatic stress disorder (PTSD). The current study is based on the hypothesis that improvements in cognitive control processes related to executive functioning and attention after GOALS training generalize to improvements in emotional functioning, thereby resulting in reductions in emotional distress. The current study analyzed archival data from 33 Veteran participants with a confirmed diagnosis of PTSD and a history of mild TBI who received either GOALS training or a psychoeducational intervention matched for time, therapist attention, and participation format. Regression analysis was used to assess the strength of the relationship between improvements in Overall Attention/Executive Functioning and decreases in hyperarousal symptoms associated with PTSD. Results from the regression analysis revealed that improvements in Overall Attention/Executive Functioning after GOALS was significantly associated with reductions in hyperarousal symptoms associated with PTSD (R² = 0.26, F_(1,15) = 5.01, β = -.51, p < .05). The current findings suggest that cognitive improvements after GOALS training may lead to changes in emotional functioning, resulting in decreased emotional distress. This is important, particularly in VA settings, because the results potentially highlight additional areas of research and focus on the treatment of comorbid mild TBI and PTSD among Veterans.

Teasing apart trauma: neural oscillations differentiate individual cases of mild traumatic brain injury from post-traumatic stress disorder even when symptoms overlap

Post-traumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are highly prevalent and closely related disorders. Affected individuals often exhibit substantially overlapping symptomatology - a major challenge for differential diagnosis in both military and civilian contexts. According to our symptom assessment, the PTSD group exhibited comparable levels of concussion symptoms and severity to the mTBI group. An objective and reliable system to uncover the key neural signatures differentiating these disorders would be an important step towards translational and applied clinical use. Here we explore use of MEG (magnetoencephalography)-multivariate statistical learning analysis in identifying the neural features for differential PTSD/mTBI characterisation. Resting state MEG-derived regional neural activity and coherence (or functional connectivity) across seven canonical neural oscillation frequencies (delta to high gamma) were used. The selected features were consistent and largely confirmatory with previously established neurophysiological markers for the two disorders. For regional power from theta, alpha and high gamma bands, the amygdala, hippocampus and temporal areas were identified. In line with regional activity, additional connections within the occipital, parietal and temporal regions were selected across a number of frequency bands. This study is the first to employ MEG-derived neural features to reliably and differentially stratify the two disorders in a multi-group context. The features from alpha and beta bands exhibited the best classification performance, even in cases where distinction by concussion symptom profiles alone were extremely difficult. We demonstrate the potential of using 'invisible' neural indices of brain functioning to understand and differentiate these debilitating conditions.

Self-Rated Health Among Patients With Severe Traumatic Brain Injury and Their Close Relatives: The Role of Posttraumatic Stress Symptoms

OBJECTIVE

Severe traumatic brain injury (sTBI) is accompanied by significant declines in self-rated health (SRH). Although such deteriorations in SRH are related to various consequences of sTBI, the effect of posttraumatic reactions (i.e., posttraumatic stress [PTS] symptoms) has been tested insufficiently to date, especially among civilians. The present investigation is based on Trajectories of Recovery After Severe Traumatic brain injury-Matters In families (TRAST-MI), a unique study among civilians with sTBI and their families. Previous research revealed that civilian sTBI has effects beyond the injured patient, influencing their close relatives as well. The aim of this study was to assess the association between PTS symptoms and SRH among patients with civilian sTBI and their close relatives.

METHODS

Patients with sTBI (assessed by an Abbreviated Injury Scale of the head region score >3) and their close relatives participated in TRAST-MI. One hundred twenty-six patient-relative dyads were assessed at 3, 6, and 12 months after the injury.

RESULTS

Multilevel modeling revealed that patients' PTS symptoms were associated with consequent SRH (slope = 0.42; p < .001), and relatives' PTS symptoms were associated with their respective SRH (slope = 0.2; p = .012).

CONCLUSIONS

The findings of this study reveal that SRH of both patients with sTBI and their relatives are negatively affected by their own PTS symptoms. These findings underline the understanding that sTBI is not merely a medical trauma but rather a comprehensive psychosocial trauma, which has consequences for the whole family system.

Oxidative Dysregulation in Early Life Stress and Posttraumatic Stress Disorder: A Comprehensive Review

Traumatic stress may chronically affect master homeostatic systems at the crossroads of peripheral and central susceptibility pathways and lead to the biological embedment of trauma-related allostatic trajectories through neurobiological alterations even decades later. Lately, there has been an exponential knowledge growth concerning the effect of traumatic stress on oxidative components and redox-state homeostasis. This extensive review encompasses a detailed description of the oxidative cascade components along with their physiological and pathophysiological functions and a systematic presentation of both preclinical and clinical, genetic and epigenetic human findings on trauma-related oxidative stress (OXS), followed by a substantial synthesis of the involved oxidative cascades into specific and functional, trauma-related pathways. The bulk of the evidence suggests an imbalance of pro-/anti-oxidative mechanisms under conditions of traumatic stress, respectively leading to a systemic oxidative dysregulation accompanied by toxic oxidation byproducts. Yet, there is substantial heterogeneity in findings probably relative to confounding, trauma-related parameters, as well as to the equivocal directionality of not only the involved oxidative mechanisms but other homeostatic ones. Accordingly, we also discuss the trauma-related OXS findings within the broader spectrum of systemic interactions with other major influencing systems, such as inflammation, the hypothalamic-pituitary-adrenal axis, and the circadian system. We intend to demonstrate the inherent complexity of all the systems involved, but also put forth associated caveats in the implementation and interpretation of OXS findings in trauma-related research and promote their comprehension within a broader context.

Translational relevance of fear conditioning in rodent models of mild traumatic brain injury

Mild traumatic brain injury (mTBI) increases the risk of posttraumatic stress disorder (PTSD) in military populations. Utilizing translationally relevant animal models is imperative for establishing a platform to delineate neurobehavioral deficits common to clinical PTSD that emerge in the months to years following mTBI. Such platforms are required to facilitate preclinical development of novel therapeutics. First, this mini review provides an overview of the incidence of PTSD following mTBI in military service members. Secondly, the translational relevance of fear conditioning paradigms used in conjunction with mTBI in preclinical studies is evaluated. Next, this review addresses an important gap in the current preclinical literature; while incubation of fear has been studied in other areas of research, there are relatively few studies pertaining to the enhancement of cued and contextual fear memory over time following mTBI. Incubation of fear paradigms in conjunction with mTBI are proposed as a novel behavioral approach to advance this critical area of research. Lastly, this review discusses potential neurobiological substrates implicated in altered fear memory post mTBI.

The additional burden of PTSD on functioning and depression in veterans with traumatic brain injury

BACKGROUND

Many United States veterans and active military with a history of traumatic brain injury (TBI) also experience challenges from comorbid posttraumatic stress disorder (PTSD), yet the additional burden of PTSD is not clear.

PURPOSE

To address this knowledge gap, this study examined the relationship of PTSD to cognitive, social, and physical functioning and depressive symptoms in veterans recently diagnosed with TBI.

METHODS

Veterans were recruited from a VA rehabilitation clinic. The Patient Competency Rating Scale and Center for Epidemiologic Studies Depression Scale measured functioning and depression, respectively. Chart review captured PTSD diagnosis.

FINDINGS

In the sample of 83 veterans, 65% had a current PTSD diagnosis. After controlling for sociodemographic variables and TBI severity, PTSD was a significant predictor of lower cognitive, social, and physical functioning and higher depressive symptomatology.

DISCUSSION

Clinicians should incorporate PTSD assessment in their work with veterans with TBI. Integrated behavioral health and rehabilitation interventions that provide strategies for veterans to manage TBI symptoms and PTSD are critical.

Blast in Context: The Neuropsychological and Neurocognitive Effects of Long-Term Occupational Exposure to Repeated Low-Level Explosives on Canadian Armed Forces' Breaching Instructors and Range Staff

Currently, there is strong interest within the military to better understand the effects of long-term occupational exposure to repeated low-level blast on health and performance. To gain traction on the chronic sequelae of blast, we focused on breaching—a tactical technique for gaining entry into closed/blocked spaces by placing explosives and maintaining a calculated safe distance from the detonation. Using a cross-sectional design, we compared the neuropsychological and neurocognitive profiles of breaching instructors and range staff to sex- and age-matched Canadian Armed Forces (CAF) controls. Univariate tests demonstrated that breaching was associated with greater post-concussive symptoms (Rivermead Post Concussion Symptoms Questionnaire) and lower levels of energy (RAND SF-36). In addition, breaching instructors and range staff were slower on a test that requires moving and thinking simultaneously (i.e., cognitive-motor integration). Next, using a multivariate approach, we explored the impact of other possible sources of injury, including concussion and prior war-zone deployment on the same outcomes. Concussion history was associated with higher post-concussive scores and musculoskeletal problems, whereas deployment was associated with higher post-concussive scores, but lower energy and greater PTSD symptomatology (using PCL-5). Our results indicate that although breaching, concussion, and deployment were similarly correlated with greater post-concussive symptoms, concussion history appears to be uniquely associated with altered musculoskeletal function, whereas deployment history appears to be uniquely associated with lower energy and risk of PTSD. We argue that the broader injury context must, therefore, be considered when studying the impact of repetitive low-level explosives on health and performance in military members.

Customizing TMS Applications in Traumatic Brain Injury Using Neuroimaging

Optimizing transcranial magnetic stimulation (TMS) treatments in traumatic brain injury (TBI) and co-occurring conditions may benefit from neuroimaging-based customization.

PARTICIPANTS

Our total sample (N = 97) included 58 individuals with TBI (49 mild, 8 moderate, and 1 severe in a state of disordered consciousness), of which 24 had co-occurring conditions (depression in 14 and alcohol use disorder in 10). Of those without TBI, 6 individuals had alcohol use disorder and 33 were healthy controls. Of our total sample, 54 were veterans and 43 were civilians.

DESIGN

Proof-of-concept study incorporating data from 5 analyses/studies that used multimodal approaches to integrate neuroimaging with TMS.

MAIN MEASURES

Multimodal neuroimaging methods including structural magnetic resonance imaging (MRI), MRI-guided TMS navigation, functional MRI, diffusion MRI, and TMS-induced electric fields. Outcomes included symptom scales, neuropsychological tests, and physiological measures.

RESULTS

It is feasible to use multimodal neuroimaging data to customize TMS targets and understand brain-based changes in targeted networks among people with TBI.

CONCLUSIONS

TBI is an anatomically heterogeneous disorder. Preliminary evidence from the 5 studies suggests that using multimodal neuroimaging approaches to customize TMS treatment is feasible. To test whether this will lead to increased clinical efficacy, studies that integrate neuroimaging and TMS targeting data with outcomes are needed.

Evaluation of an Immunomodulatory Probiotic Intervention for Veterans With Co-occurring Mild Traumatic Brain Injury and Posttraumatic Stress Disorder: A Pilot Study

Background: US military Veterans returned from Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn (OEF/OIF/OND) with symptoms associated with mild traumatic brain injury [mTBI; i.e., persistent post-concussive (PPC) symptoms] and posttraumatic stress disorder (PTSD). Interventions aimed at addressing symptoms associated with both physical and psychological stressors (e.g., PPC and PTSD symptoms) are needed. This study was conducted to assess the feasibility, acceptability, and safety of a probiotic intervention, as well as to begin the process of evaluating potential biological outcomes.

Methods: A pilot randomized controlled trial was implemented among US military Veterans from recent conflicts in Iraq and Afghanistan. Those enrolled had clinically significant PPC and PTSD symptoms. Participants were randomized to intervention (Lactobacillus reuteri DSM 17938) or placebo supplementation (daily for 8 weeks +/- 2 weeks) at a 1:1 ratio, stratified by irritable bowel syndrome status. Thirty-one Veterans were enrolled and randomized (15 to the placebo condition and 16 to the probiotic condition).

Results: Thresholds for feasibility, acceptability, and safety were met. Probiotic supplementation resulted in a decrease in plasma C-reactive protein (CRP) concentrations relative to the placebo group that approached statistical significance (p = 0.056). Although during the Trier Social Stress Test (TSST; administered post-supplementation) no between-group differences were found on a subjective measure of stress responsivity (Visual Analog Scale), there was a significantly larger increase in mean heart beats per minute between baseline and the math task for the placebo group as compared with the probiotic group (estimated mean change, probiotic 5.3 [95% Confidence Interval: −0.55, 11.0], placebo 16.9 [11.0, 22.7], p = 0.006).

Conclusions: Findings from this trial support the feasibility, acceptability, and safety of supplementation with an anti-inflammatory/immunoregulatory probiotic, L. reuteri DSM 17938, among Veterans with PPC and PTSD symptoms. Moreover, results suggest that CRP may be a viable inflammatory marker of interest. A larger randomized controlled trial aimed at measuring both biological and clinical outcomes is indicated.

Clinical Trial Registration:ClinicalTrials.gov, Identifier NCT02723344.