Care of war veterans with mild traumatic brain injury--flawed perspectives

Anatomical Features and Material Properties of Human Surrogate Head Models Affect Spatial and Temporal Brain Motion under Blunt Impact

Traumatic brain injury (TBI) is a biomechanical problem where the initiating event is dynamic loading (blunt, inertial, blast) to the head. To understand the relationship between the mechanical parameters of the injury and the deformation patterns in the brain, we have previously developed a surrogate head (SH) model capable of measuring spatial and temporal deformation in a surrogate brain under blunt impact. The objective of this work was to examine how material properties and anatomical features affect the motion of the brain and the development of injurious deformations. The SH head model was modified to study six variables independently under blunt impact: surrogate brain stiffness, surrogate skull stiffness, inclusion of cerebrospinal fluid (CSF), head/skull size, inclusion of vasculature, and neck stiffness. Each experimental SH was either crown or frontally impacted at 1.3 m/s (3 mph) using a drop tower system. Surrogate brain material, the Hybrid III neck stiffness, and skull stiffness were measured and compared to published properties. Results show that the most significant variables affecting changes in brain deformation are skull stiffness, inclusion of CSF and surrogate brain stiffness. Interestingly, neck stiffness and SH size significantly affected the strain rate only suggesting these parameters are less important in blunt trauma. While the inclusion of vasculature locally created strain concentrations at the interface of the artery and brain, overall deformation was reduced.

Military and Nonmilitary TBI Associations with Hearing Loss and Self-Reported Hearing Difficulty among Active-Duty Service Members and Veterans

OBJECTIVE

Identify associations between self-reported history of military and nonmilitary traumatic brain injury (TBI) on hearing loss and hearing difficulty from the Noise Outcomes in Servicemembers Epidemiology (NOISE) study.

STUDY DESIGN

Cross-sectional.

SETTING

Multi-institutional tertiary referral centers.

PATIENTS

Four hundred seventy-three Active-Duty Service members (ADSM) and 502 veterans.

EXPOSURE

Self-reported history of no TBI, military TBI only, nonmilitary TBI only, both military and nonmilitary TBI.

MAIN OUTCOME MEASURES

Pure-tone hearing thresholds, Speech Recognition In Noise Test (SPRINT), Hearing Handicap Inventory for Adults (HHIA), and Speech, Spatial and Qualities of Hearing Scale (SSQ)-12.

RESULTS

25% (120/473) of ADSM and 41% (204/502) of veterans self-reported a TBI. Military TBI was associated with poorer hearing thresholds in all frequency ranges in veterans (adjusted mean difference, 1.8 dB; 95% confidence interval [CI], 0.5-3.0; 3.3, 0.8-5.8; 5.1; 1.7-8.5, respectively), and in the high frequency range in ADSM (mean difference, 3.2 dB; 95% CI, 0.1-6.3). Veterans with military TBI only and nonmilitary TBI only had lower odds of correctly identifying speech in noise than veterans with no TBI (odds ratio [OR], 0.78; 95% CI, 0.72-0.83; 0.90; 0.84-0.98). ADSM with a military TBI (OR, 5.7; 95% CI, 2.6-12.5) and veterans with any TBI history (OR, 2.5; 95% CI, 1.5-4.3; OR, 2.2; 95% CI, 1.3-3.8; OR, 4.5; 95% CI, 2.1-9.8) were more likely to report hearing difficulty on HHIA. SSQ-12 results corroborated HHIA findings.

CONCLUSIONS

Military TBI was associated with poorer hearing thresholds in veterans and ADSM, and poorer SPRINT scores in veterans. Military TBI was associated with poorer self-perceived hearing ability in ADSM. All types of TBI were associated with poorer self-perceived hearing ability in veterans, although the strength of this association was greatest for military TBI.

A narrative review of the effects of dexamethasone on traumatic brain injury in clinical and animal studies: focusing on inflammation

Traumatic brain injury (TBI) is a type of brain injury resulting from a sudden physical force to the head. TBI can range from mild, such as a concussion, to severe, which might result in long-term complications or even death. The initial impact or primary injury to the brain is followed by neuroinflammation, excitotoxicity, and oxidative stress, which are the hallmarks of the secondary injury phase, that can further damage the brain tissue. Dexamethasone (DXM) has neuroprotective effects. It reduces neuroinflammation, a critical factor in secondary injury-associated neuronal damage. DXM can also suppress the microglia activation and infiltrated macrophages, which are responsible for producing pro-inflammatory cytokines that contribute to neuroinflammation. Considering the outcomes of this research, some of the effects of DXM on TBI include: (1) DXM-loaded hydrogels reduce apoptosis, neuroinflammation, and lesion volume and improves neuronal cell survival and motor performance, (2) DXM treatment elevates the levels of Ndufs2, Gria3, MAOB, and Ndufv2 in the hippocampus following TBI, (3) DXM decreases the quantity of circulating endothelial progenitor cells, (4) DXM reduces the expression of IL1, (5) DXM suppresses the infiltration of RhoA + cells into primary lesions of TBI and (6) DXM treatment led to an increase in fractional anisotropy values and a decrease in apparent diffusion coefficient values, indicating improved white matter integrity. According to the study, the findings show that DXM treatment has neuroprotective effects in TBI. This indicates that DXM is a promising therapeutic approach to treating TBI.

Blood-Based Biomarkers of Repetitive, Subconcussive Blast Overpressure Exposure in the Training Environment: A Pilot Study

Because of their unknown long-term effects, repeated mild traumatic brain injuries (TBIs), including the low, subconcussive ones, represent a specific challenge to healthcare systems. It has been hypothesized that they can have a cumulative effect, and they may cause molecular changes that can lead to chronic degenerative processes. Military personnel are especially vulnerable to consequences of subconcussive TBIs because their training involves repeated exposures to mild explosive blasts. In this pilot study, we collected blood samples at baseline, 6 h, 24 h, 72 h, 2 weeks, and 3 months after heavy weapons training from students and instructors who were exposed to repeated subconcussive blasts. Samples were analyzed using the reverse and forward phase protein microarray platforms. We detected elevated serum levels of glial fibrillary acidic protein, ubiquitin C-terminal hydrolase L1 (UCH-L1), nicotinic alpha 7 subunit (CHRNA7), occludin (OCLN), claudin-5 (CLDN5), matrix metalloprotease 9 (MMP9), and intereukin-6 (IL-6). Importantly, serum levels of most of the tested protein biomarkers were the highest at 3 months after exposures. We also detected elevated autoantibody titers of proteins related to vascular and neuroglia-specific proteins at 3 months after exposures as compared to baseline levels. These findings suggest that repeated exposures to subconcussive blasts can induce molecular changes indicating not only neuron and glia damage, but also vascular changes and inflammation that are detectable for at least 3 months after exposures whereas elevated titers of autoantibodies against vascular and neuroglia-specific proteins can indicate an autoimmune process.

Network Analysis of Neurobehavioral and Posttraumatic Stress Disorder Symptoms One Year after Traumatic Brain Injury: A Veterans Affairs TBI Model Systems Study

Traumatic brain injury (TBI) is often experienced under stressful circumstances that can lead to both symptoms of posttraumatic stress disorder (PTSD) and neurobehavioral symptoms of brain injury. There is considerable symptom overlap in the behavioral expression of these conditions. Psychometric network analysis is a useful approach to investigate the role of specific symptoms in connecting these two disorders and is thus well-suited to explore their interrelatedness. This study applied network analysis to examine the associations among PTSD and TBI symptoms in a sample of Service Members and Veterans (SM/Vs) with a history of TBI one year after injury. Responses to the Neurobehavioral Symptom Inventory (NSI) and PTSC Checklist-Civilian version (PCL-C) were obtained from participants who completed comprehensive inpatient rehabilitation services at five VA polytrauma rehabilitation centers. Participants (N = 612) were 93.1% male with an average age of 36.98 years at injury. The analysis produced a stable network. Within the NSI symptom groups, the frustration symptom was an important bridge between the affective and cognitive TBI symptoms. The PCL-C nodes formed their own small cluster with hyperarousal yielding connections with the affective, cognitive, and somatic symptom groups. Consistent with this observation, the hyperarousal node had the second strongest bridge centrality in the network. Hyperarousal appears to play a key role in holding together this network of distress and thus represents a prime target for intervention among individuals with elevated symptoms of PTSD and a history of TBI. Network analysis offers an empirical approach to visualizing and quantifying the associations among symptoms. The identification of symptoms that are central to connecting multiple conditions can inform diagnostic precision and treatment selection.

Reference Values for the Headache Impact Test-6 Questionnaire

OBJECTIVE

To determine reference values for the Headache Impact Test-6 (HIT-6) in a young, physically active cohort and to examine the influence of sex, concussion history, headache history, and competitive sport level on HIT-6 scores.

DESIGN

Cross-sectional.

SETTING

United States Service Academy.

PARTICIPANTS

United States Service Academy cadets (N=2678) completed an HIT-6 questionnaire as part of their annual concussion baseline assessment. Cadets with a recent concussion were excluded from baseline testing.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Reference values were calculated and stratified by sex, concussion history, headache history, and competitive sport level. Mann-Whitney U and Kruskal-Wallis tests were used to examine the effect of sex, concussion history, headache history, and competitive sport level on HIT-6 scores (P<.05).

RESULTS

Of the 3599 cadets baselined, 2687 cadets (23% female) agreed to participate in the study and completed the HIT-6. Female participants reported significantly worse HIT-6 scores compared with male participants both with (P<.001) and without (P<.001) a concussion history. In both sexes, participants with a headache history reported worse scores than those with no headache/concussion history and a concussion history (all P<.005). Female cadets who participated in intramural athletics reported worse HIT-6 scores at baseline than female intercollegiate athletes (P=.003).

CONCLUSIONS

This is the first study to stratify HIT-6 data by sex, concussion history, headache history, and sport level in a collegiate population at risk for concussions. Sex and headache history appear to influence HIT-6 scores and should be given special consideration when interpreting health-related quality of life deficits due to headache.

The Role of Presumed Head and Neck Injuries in Emotion Dysregulation Among Community Women With a History of Physical Intimate Partner Violence

Intimate partner violence (IPV) is prevalent among women and associated with negative outcomes, including emotion dysregulation. Limited research has examined factors that contribute to emotion dysregulation in this population. This study explores the potential influence of presumed head and neck injuries from IPV on five dimensions of emotion dysregulation. Participants were 352 community women who responded to an online survey. Results of a path analysis indicated that presumed head and neck injuries from IPV were significantly associated with lack of emotional clarity and difficulties engaging in goal-directed behaviors when experiencing emotions. Findings suggest an association between presumed head and neck injuries from IPV and emotion dysregulation, underscoring the potential need for considering both neurological and psychological factors in the assessment and treatment of emotion dysregulation in this population.

Understanding the Link Between Traumatic Brain Injury Accompanied by Loss of Consciousness and Well-Being: A Sample of UK Military Veterans

OBJECTIVE

To investigate the association between reported traumatic brain injury plus loss of consciousness (TBI + LOC) and a range of demographic, military, and physical and mental health factors among a sample of UK veterans seeking support for mental health difficulties.

DESIGN

The present study was a cross-sectional study.

PARTICIPANTS

Clinical records were used to identify a sample of treatment-seeking UK veterans (N = 3335), of which a total of 403 took part.

MAIN MEASURES

Information on demographic characteristics, military experiences, and a range of physical and mental health difficulties was collected.

RESULTS

Almost half of the sample (48%) reported a TBI + LOC, which was most strongly associated with drug use and childhood adversity. More modest associations also emerged with earlier service termination, likelihood of unemployment, as well as chronic pain and poor mobility.

CONCLUSION

The findings suggested that TBI + LOC may not specifically be associated with symptoms of posttraumatic stress in a sample of treatment-seeking veterans. The demonstrated links between TBI + LOC and adverse childhood, drug use, physical health, and employment may be useful in improving the assessment and rehabilitation of veterans with TBI + LOC.

Goal-Oriented Attention Self-Regulation Training Improves Executive Functioning in Veterans with Post-Traumatic Stress Disorder and Mild Traumatic Brain Injury

Difficulties in executive-control functions are common sequelae of both traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). The goal of this study was to assess whether a cognitive rehabilitation training that was applied successfully in civilian and military TBI would be effective for military Veterans with comorbid PTSD and mild TBI (mTBI). In the previous study, Veterans with a history of mild to severe TBI improved significantly after goal-oriented attentional self-regulation (GOALS) training on measures of attention/executive function, functional task performance, and emotional regulation. The objective of this study was to assess effects of GOALS training in Veterans with comorbid PTSD and mTBI. Forty Veterans with a current PTSD diagnosis and history of mTBI (6+ months post) were randomized to either five weeks of GOALS or Brain-Health Education (BHE) training matched in time and intensity. Evaluator-blinded assessments at baseline and post-training included neuropsychological and complex functional task performance, and self-report measures of emotional functioning/regulation. After GOALS but not BHE training, participants significantly improved from baseline on primary outcome measures of: overall complex attention/executive function neuropsychological performance composite (F = 12.35, p = 0.001; Cohen d = 0.48), and overall mood disturbance -POMS emotional regulation self-report (F = 4.29, p = 0.05, Cohen d = 0.41). In addition, GOALS but not BHE participants indicated a significant decrease in PTSD symptoms (PCL-M Total Score) (F = 4.80, p = 0.05, Cohen d = 0.60), and demonstrated improvement on complex functional task performance-GPS Learning and Memory (F = 5.06, p = 0.05, Cohen d = 0.56]. Training in attentional self-regulation applied to participant-defined goals may improve cognitive functioning in Veterans with comorbid PTSD and mTBI. Improving cognitive control functioning may also improve functioning in other domains such as emotional regulation and functional performance, potentially making it particularly relevant for Veterans with a history of mTBI and comorbid psychiatric symptoms.

The Impact of Common Psychiatric and Behavioral Comorbidities on Functional Disability Across Time and Individuals in Post-9/11 Veterans

Returning veterans often face multiple concurrent psychiatric and behavioral conditions that negatively impact reintegration into civilian life and are associated with functional disability. Understanding how conditions interact to negatively impact functioning is an important step toward developing holistic treatment approaches optimized for this population. This study utilized a cross-sectional and prospective longitudinal cohort design, applying regression algorithms to understand the relative contribution of common clinical issues to functional disability in U.S. veterans who served after the September 11, 2001 (9/11), terror attacks. Community-dwelling post-9/11 veterans (N = 397) completed detailed assessments, including common clinical condition diagnoses, combat experience, and demographics, which were used to predict functional disability (World Health Organization Disability Assessment Schedule); 205 participants were reassessed approximately 1-2 years after enrollment. Regression analyses showed a strong association between the predictor variables and functional disability, f ² = 1.488. Validation analyses showed a high prediction ability of functional disability to independent samples, r = .719, and across time in the same individuals, r = .780. The strongest predictors included current posttraumatic stress disorder, depressive disorder, sleep disturbance, and pain diagnoses. These results demonstrate the importance of considering multiple common co-occurring conditions when assessing functional disability in post-9/11 veterans and suggest that certain syndromes contribute the most unique information to predicting functional disability with high confidence. As most U.S. veterans utilize private healthcare systems, these results have clinical utility for both Veterans Affairs and civilian healthcare practitioners in assessing and monitoring functional disability in post-9/11 veterans over time.

Factors Associated With Delayed Concussion Reporting by United States Service Academy Cadets

CONTEXT

Approximately half of individuals who sustain a concussion do not immediately report their injuries. Motivators for not reporting include thinking the suspected concussion was not a serious injury and wanting to continue participating in activity. Additionally, military personnel have concerns about how concussions may affect their careers. However, delayed reporting can prolong neurobehavioral recovery. Understanding the frequency of delayed reporting and contributing factors will aid in identifying individuals who may be more likely to delay reporting.

OBJECTIVE

To describe the frequency of delayed concussion reporting by service academy cadets and determine if sex, injury setting, sport level, or medical history is capable of predicting delayed reporting.

DESIGN

Cohort study.

SETTING

Service academies.

PATIENTS OR OTHER PARTICIPANTS

A total of 316 patients with concussions were observed from January 2014 to August 2016.

MAIN OUTCOME MEASURE(S)

All cadets completed an annual concussion baseline collection of demographic, medical history, and sports participation information. Delayed concussion reporting served as the outcome variable. Predictor variables were sex, injury setting, and sport level, as well as concussion, headache, and learning disorder history. Frequencies were calculated to describe the proportion of participants who delayed reporting. Univariable and multivariable logistic regression models were used to assess if the predictor variables were associated with delayed concussion reporting. Odds ratios (ORs) and 95% confidence intervals were calculated for all variables included in the final model.

RESULTS

Of the patients with concussion, 51% were classified as delayed reporting. In univariable models, females (OR = 1.70) and National Collegiate Athletic Association cadet-athletes (OR = 1.98) were more likely to delay reporting than males and intramural cadet-athletes, respectively. The multivariable model yielded similar findings.

CONCLUSIONS

Roughly half of the cadets who sustained a concussion failed to immediately report their injury. Specifically, our data suggested that female cadets, cadets injured outside of competition, and highly competitive cadet-athletes were almost twice as likely to delay reporting as others.

Posttraumatic stress symptomatology and abnormal neural responding during emotion regulation under cognitive demands: mediating effects of personality

Posttraumatic stress disorder (PTSD) is often complicated by the after-effects of mild traumatic brain injury (mTBI). The mixture of brain conditions results in abnormal affective and cognitive functioning, as well as maladaptive behavior. To better understand how brain activity explains cognitive and emotional processes in these conditions, we used an emotional N-back task and functional magnetic resonance imaging (fMRI) to study neural responses in US military veterans after deployments to Iraq and Afghanistan. Additionally, we sought to examine whether hierarchical dimensional models of maladaptive personality could account for the relationship between combat-related brain conditions and fMRI responses under cognitive and affective challenge. FMRI data, measures of PTSD symptomatology (PTSS), blast-induced mTBI (bmTBI) severity, and maladaptive personality (MMPI-2-RF) were gathered from 93 veterans. Brain regions central to emotion regulation were selected for analysis, and consisted of bilateral amygdala, bilateral dorsolateral prefrontal (dlPFC), and ventromedial prefrontal/subgenual anterior cingulate (vmPFC-sgACC). Cognitive load increased activity in dlPFC and reduced activity in emotional responding brain regions. However, individuals with greater PTSS showed blunted deactivations in bilateral amygdala and vmPFC-sgACC, and weaker responses in right dlPFC. Additionally, we found that elevated emotional/internalizing dysfunction (EID), specifically low positive emotionality (RC2), accounted for PTSS-related changes in bilateral amygdala under increased cognitive load. Findings suggest that PTSS might result in amygdala and vmPFC-sgACC activity resistant to moderation by cognitive demands, reflecting emotion dysregulation despite a need to marshal cognitive resources. Anhedonia may be an important target for interventions that improve the affective and cognitive functioning of individuals with PTSD.

The effect of diagnostic terminology on cognitive, emotional, and post-concussive sequelae following mild brain injury

Objective: We sought to determine whether the diagnostic terms 'mild traumatic brain injury (mTBI)' and 'concussion' result in differences in perceived cognitive, emotional, and post-concussive sequelae.Method: A total of 81 healthy university students (79% female; 69% of Asian descent) were randomly assigned to one of two conditions: mTBI (n = 41), or concussion (n = 40), and were instructed to simulate on a battery of cognitive (Neuropsychological Assessment Battery - Screening Module), emotional (Beck Anxiety Inventory, Beck Depression Inventory-II), and post-concussive (Rivermead Postconcussive Symptoms Questionnaire) measures.Results: There were no significant group differences between expected cognitive, emotional, or post-concussive consequences. However, both groups received poorer scores than the normative data.Conclusions: These results suggest that diagnostic terminology does not appear to influence anticipated recovery following mild brain injury. However, the presentation of information about the injury itself may impact recovery outcomes. This study provides preliminary support for the potential negative effects that may arise as a result of providing participants with non-evidence based information about mild brain injuries.

Veterans Health Administration nurses' training and beliefs related to care of patients with traumatic brain injury

BACKGROUND

Veteran patients with traumatic brain injury (TBI) and their family members regularly receive care from nurses. Understanding nurses' training and beliefs can provide direction for intervention work aimed at ensuring the best possible care is delivered to this population.

AIMS

We examined Veterans Health Administration (VHA) nurses' training and beliefs related to care of patients with moderate-to-severe TBI.

DESIGN AND METHODS

We conducted an exploratory, cross-sectional survey with 211 VHA nurses and analyzed data using descriptive statistics.

RESULTS

The average years of nursing experience was 18 years, and 90% reported ever caring for a patient with TBI. Most nurses (70%) reported only seeing patients with TBI ≤1-2 times per year in their current role; 20% reported seeing these patients 1-2 times per month. Even with infrequent care, almost 50% reported previously receiving TBI-related training. Beliefs items with the highest accuracy indicated nurses agreed that they need specialized training to care for patients with TBI and that TBI recovery may continue for several years (96.39% accuracy respectively). The beliefs item with the lowest accuracy indicated focus on whether nurses agreed that TBI severity was important in developing care plans (27.84% accuracy). Nurses reported the need for clarity of the nursing role in caring for patients with TBI (77.32% agreement).

CONCLUSION

VHA nurses do have accurate beliefs about caring for Veteran patients with moderate-to-severe TBI; however, there is the need for further role clarification regarding nursing care of patients with TBI.

IMPACT

These findings have implications for development of education and training interventions for nurses who care for Veteran patients with TBI.

Long-Term Effect of Cognitive Rehabilitation Regardless of Prerehabilitation Cognitive Status for Veterans with TBI

Persisting difficulties in executive functioning (EF) are common after traumatic brain injury (TBI). Cognitive rehabilitation can be effective, but the impact of pretreatment neurocognitive functioning on long term effects of rehabilitation is unknown. Because this information can impact treatment planning, we examined the relationship between prerehabilitation neurocognitive status and long-term effects of EF training. Archival data were drawn from a trial of Goal-Oriented Attentional Self-Regulation group-format EF training for Veterans with TBI [mild-severe; 11 years postinjury; 96% male, 32% nonwhite, 14.21 years education (SD 1.72), 41.13 years old (SD 11.39)]. Using prerehabilitation neurocognitive performance, participants were clustered into cognitive difficulty (CD) and cognitively normal (CN) groups. Six-plus months after EF rehabilitation training, participants completed a structured telephone interview and/or in-person cognitive/functional/emotional assessment using standardized measures of cognitive, daily, and emotional functioning frequently employed in TBI research. At 6+ months post-EF training compared to prerehabilitation, CD and CN improved in multiple cognitive (Overall Attention/EF: F(1,18) = 26.17, partial η² = .59; Total Memory: F(1,18) = 6.82, partial η² = .28) and functional domains (Goal Processing Scale [GPS] total score: F(1,15) = 6.71, partial η² = .31). CD improved more than CN on Learning and Memory functional domain [F(1,15) = 6.10, partial η² = .29]. Results of our small archival analysis raise the possibility that Veterans with chronic TBI may demonstrate long-term effects of EF training.

Dynamics of Segregation and Integration in Directional Brain Networks: Illustration in Soldiers With PTSD and Neurotrauma

Brain functioning relies on various segregated/specialized neural regions functioning as an integrated-interconnected network (i.e., metastability). Various psychiatric and neurologic disorders are associated with aberrant functioning of these brain networks. In this study, we present a novel framework integrating the strength and temporal variability of metastability in brain networks. We demonstrate that this approach provides novel mechanistic insights which enables better imaging-based predictions. Using whole-brain resting-state fMRI and a graph-theoretic framework, we integrated strength and temporal-variability of complex-network properties derived from effective connectivity networks, obtained from 87 U.S. Army soldiers consisting of healthy combat controls (n = 28), posttraumatic stress disorder (PTSD; n = 17), and PTSD with comorbid mild-traumatic brain injury (mTBI; n = 42). We identified prefrontal dysregulation of key subcortical and visual regions in PTSD/mTBI, with all network properties exhibiting lower variability over time, indicative of poorer flexibility. Larger impairment in the prefrontal-subcortical pathway but not prefrontal-visual pathway differentiated comorbid PTSD/mTBI from the PTSD group. Network properties of the prefrontal-subcortical pathway also had significant association (R ² = 0.56) with symptom severity and neurocognitive performance; and were also found to possess high predictive ability (81.4% accuracy in classifying the disorders, explaining 66-72% variance in symptoms), identified through machine learning. Our framework explained 13% more variance in behaviors compared to the conventional framework. These novel insights and better predictions were made possible by our novel framework using static and time-varying network properties in our three-group scenario, advancing the mechanistic understanding of PTSD and comorbid mTBI. Our contribution has wide-ranging applications for network-level characterization of healthy brains as well as mental disorders.

Long-term effects of executive function training among veterans with chronic TBI

Objective: To investigate long-term effects of GOALS executive function training in Veterans with chronic TBI. In a recently completed study Veterans with chronic TBI showed improvement immediately post-GOALS but not control training on measures of executive function, functional task performance, and emotion regulation. We now examine the long-term maintenance of post-GOALS training changes in the same sample. Setting: San Francisco VA Health Care System (SFVAHCS), and VA Northern California Health-Care System (VANCHS) in Martinez. Participants and Design: 24 Veterans with chronic TBI were assessed at baseline, post-GOALS training, and long-term follow-up 6+ months following completion of training with a structured telephone interview, neuropsychological and complex functional performance measures, and self-report measures of daily and emotional functioning. Results: Participants reported an increased likelihood of involvement in competitive employment/volunteering at follow-up (61%) compared to baseline (26%; χ2 = 5.66, p < .01, ѱ = .35). Repeated measures MANOVAS indicated improvement on attention/executive function (F = 13.85, p < .01, partial η2 = .42), complex functional task performance (GPS Total: F = 9.12, p < .01, partial η2 = .38) and daily functioning (MPAI Total: F = 3.23, p < .05, partial η2 = .21), and reduction in overall mood disturbance (POMS Total: F = 3.42, p < .05, partial η2 = .22) at follow-up relative to baseline. Discussion: Training in attention regulation applied to participant-defined goals is associated with meaningful long-term improvement in cognitive skills, emotion regulation, and daily functioning in Veterans with chronic TBI.

Executive function training in chronic traumatic brain injury patients: study protocol

Background

Some individuals who sustain traumatic brain injuries (TBIs) continue to experience significant cognitive impairments chronically (months to years post injury). Many tests of executive function are insensitive to these executive function impairments, as such impairments may only appear during complex daily life conditions. Daily life often requires us to divide our attention and focus on abstract goals. In the current study, we compare the effects of two 1-month electronic cognitive rehabilitation programs for individuals with chronic TBI. The active program (Expedition: Strategic Advantage) focuses on improving goal-directed executive functions including working memory, planning, long-term memory, and inhibitory control by challenging participants to accomplish life-like cognitive simulations. The challenge level of the simulations increases in accordance with participant achievement. The control intervention (Expedition: Informational Advantage) is identical to the active program; however, the cognitive demand level is capped, preventing participants from advancing beyond a set level. We will evaluate these interventions with a military veteran TBI population.

Methods/design

One hundred individuals will be enrolled in this double-blinded clinical trial (all participants and testers are blinded to condition). Each individual will be randomly assigned to one of two interventions. The primary anticipated outcomes are improvement of daily life cognitive function skills and daily life functions. These are measured by a daily life performance task, which tests cognitive skills, and a survey that evaluates daily life functions. Secondary outcomes are also predicted to include improvements in working memory, attention, planning, and inhibitory control as measured by a neuropsychological test battery. Lastly, neuroimaging measures will be used to evaluate changes in brain networks supporting cognition pre and post intervention.

Discussion

We will test whether electronically delivered cognitive rehabilitation aimed at improving daily life functional skills will provide cognitive and daily life functional improvements for individuals in the chronic phase of TBI recovery (greater than 3 months post injury). We aim to better understand the cognitive processes involved in recovery and the characteristics of individuals most likely to benefit. This study will also address the potential to observe generalizability or to transfer from a software-based cognitive training tool toward daily life improvement.

Trial registration

ClinicalTrials.gov, NCT03704116. Retrospectively registered on 12 Oct 2018.

Acquired Stuttering in Veterans of the Wars in Iraq and Afghanistan: The Role of Traumatic Brain Injury, Post-Traumatic Stress Disorder, and Medications

Introduction

Determine the association between acquired stuttering (AS), traumatic brain injury (TBI), and post-traumatic stress disorder (PTSD) in a cohort of 309,675 U.S. Iraq and Afghanistan veterans. The secondary aim was to determine the association between AS and medication patterns for veterans in the sample.

Materials and Methods

Retrospective study using data from the Veterans Health Administration National Repository for veterans deployed in support of combat operations in Iraq and Afghanistan and who received Veterans Health Administration care in 2010 and 2011. We identified stuttering using ICD-9 codes to establish the association between AS, TBI, and PTSD, controlling for demographic characteristics and other comorbidities. Multivariable logistic regression was used to determine the association between comorbid conditions and potentially problematic medications associated with stuttering.

Results

Two hundred thirty-five veterans (0.08%) were diagnosed with AS in the cohort. There was the greater likelihood of an AS diagnosis for veterans with concomitant TBI and PTSD when compared with veterans without these diagnoses. Over 66% of those with stuttering were prescribed at least one medication that affected speech fluency (antidepressants, anxiolytics, and antiepileptic drugs) compared with 35% of those without AS.

Conclusion

Veterans with a comorbid diagnosis of TBI and PTSD were more likely to be diagnosed with AS AOR: 9.77 (95% CI = 6.93-13.78, p < 0.05) and more likely to have been prescribed medications known to affect speech production OR: 3.68 (95% CI = 2.81-4.82, p < 0.05). Clinicians treating veterans with these complex comorbid conditions should consider the impact of medications on speech fluency.

Medical Evaluation Board Involvement, Non-Credible Cognitive Testing, and Emotional Response Bias in Concussed Service Members

Introduction

Military Service Members (SMs) with post-concussive symptoms are commonly referred for further evaluation and possible treatment to Department of Defense Traumatic Brain Injury Clinics where neuropsychological screening/evaluations are being conducted. Understudied to date, the base rates of noncredible task engagement/performance validity testing (PVT) during cognitive screening/evaluations in military settings appears to be high. The current study objectives are to: (1) examine the base rates of noncredible PVTs of SMs undergoing routine clinical or Medical Evaluation Board (MEB) related workups using multiple objective performance-based indicators; (2) determine whether involvement in MEB is associated with PVT or symptom exaggeration/symptom validity testing (SVT) results; (3) elucidate which psychiatric symptoms are associated with noncredible PVT performances; and (4) determine whether MEB participation moderates the relationship between psychological symptom exaggeration and whether or not SM goes on to demonstrate PVTs failures - or vice versa.

Materials and Methods

Retrospective study of 71 consecutive military concussion cases drawn from a DoD TBI Clinic neuropsychology clinic database. As part of neuropsychological evaluations, patients completed several objective performance-based PVTs and SVT.

Results

Mean (SD) age of SMs was 36.0 (9.5), ranging from 19-59, and 93% of the sample was male. The self-identified ethnicity resulted in the following percentages: 62% Non-Hispanic White, 22.5% African American, and 15.5% Hispanic or Latino. The majority of the sample (97%) was Active Duty Army and 51% were involved in the MEB at the time of evaluation. About one-third (35.9%) of routine clinical patients demonstrated failure on one or more PVT indicators (12.8% failed 2) while PVT failure rates amongst MEB patients ranged from 15.6% to 37.5% (i.e., failed 2 or 1 PVTs, respectively). Base rates of failures on one or more PVT did not differ between routine clinical versus MEB patients (p = 0.94). MEB involvement was not associated with increased emotional symptom response bias as compared to routine clinical patients. PVT failures were positively correlated with somatization, anxiety, depressive symptoms, suspicious and hostility, atypical perceptions/alienation/subjective cognitive difficulties, borderline personality traits/features, and penchant for aggression in addition to symptom over-endorsement/exaggeration. No differences between routine clinical and MEB patients across other SVT indicators were found. MEB status did not moderate the relationship between any of the SVTs.

Conclusion

Study results are broadly consistent with the prior published studies that documented low to moderately high base rates of noncredible task engagement during neuropsychological evaluations in military and veteran settings. Results are in contrast to prior studies that have suggested involvement in MEB is associated with increased likelihood of poor PVT performances. This is the first to show that MEB involvement did not enhance/strengthen the association between PVT performances and evidence of SVTs. Consistent with prior studies, these results do highlight that the same SMs who fail PVTs also tend to be the ones who go on to endorse a myriad of psychiatric symptoms and proclivities. Implications of variable or poor task engagement during routine clinical and MEB neuropsychological evaluation in military settings on treatment and disposition planning cannot be overstated.

Relationship of traumatic brain injury to chronic mental health problems and dementia in military veterans

Traumatic brain injury (TBI) is an unfortunately common event in military life. The conflicts in Iraq and Afghanistan have increased public awareness of TBI in the military. Certain injury mechanisms are relatively unique to the military, the most prominent being blast exposure. Blast-related mild TBI (mTBI) has been of particular concern in the most recent veterans although controversy remains concerning separation of the postconcussion syndrome associated with mTBI from post-traumatic stress disorder. TBI is also a risk factor for the development of neurodegenerative diseases including chronic traumatic encephalopathy (CTE) and Alzheimer's disease (AD). AD, TBI, and CTE are all associated with chronic inflammation. Genome wide association studies (GWAS) have identified multiple genetic loci associated with AD that implicate inflammation and - in particular microglia - as key modulators of the AD- and TBI-related degenerative processes. At the molecular level, recent studies have identified TREM2 and TYROBP/DAP12 as components of a key molecular hub linking inflammation and microglia to the pathophysiology of AD and possibly TBI. Evidence concerning the relationship of TBI to chronic mental health problems and dementia is reviewed in the context of its relevance to military veterans.

The Minnesota Multiphasic Personality Inventory-2-RF in Treatment-Seeking Veterans with History of Mild Traumatic Brain Injury

OBJECTIVE

This study examined the Minnesota Multiphasic Personality Inventory-Second Edition-Restructured Form (MMPI-2-RF) to better understand symptom presentation in a sample of treatment-seeking Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) Veterans with self-reported history of mild traumatic brain injury (mTBI).

METHOD

Participants underwent a comprehensive clinical neuropsychological battery including performance and symptom validity measures and self-report measures of depressive, posttraumatic, and post-concussive symptomatology. Those with possible symptom exaggeration (SE+) on the MMPI-2-RF were compared with those without (SE-) with regard to injury, psychiatric, validity, and cognitive variables.

RESULTS

Between 50% and 87% of participants demonstrated possible symptom exaggeration on one or more MMPI-2-RF validity scales, and a large majority were elevated on content scales related to cognitive, somatic, and emotional complaints. The SE+ group reported higher depressive, posttraumatic, and post-concussive symptomatology, had higher scores on symptom validity measures, and performed more poorly on neuropsychological measures compared with the SE- group. There were no group differences with regard to injury variables or performance validity measures. Participants were more likely to exhibit possible symptom exaggeration on cognitive/somatic compared with traditional psychopathological validity scales.

CONCLUSIONS

A sizable portion of treatment-seeking OEF/OIF Veterans demonstrated possible symptom exaggeration on MMPI-2-RF validity scales, which was associated with elevated scores on self-report measures and poorer cognitive performance, but not higher rates of performance validity failure, suggesting symptom and performance validity are distinct concepts. These findings have implications for the interpretation of clinical data in the context of possible symptom exaggeration and treatment in Veterans with persistent post-concussive symptoms.

Plasma Tau and Amyloid Are Not Reliably Related to Injury Characteristics, Neuropsychological Performance, or White Matter Integrity in Service Members with a History of Traumatic Brain Injury

The aim of this study was to examine the relationship between plasma tau and amyloid beta-42 (Aβ42), neuropsychological functioning, and white matter integrity in U.S. military service members with (n = 155) and without (n = 42) a history of uncomplicated mild (n = 83), complicated mild (n = 26), or moderate, severe, or penetrating (n = 46) traumatic brain injury (TBI). We hypothesized that higher levels of tau and Aβ42 would be related to reduced neurocognitive performance and white matter integrity. Participants were enrolled prospectively from Walter Reed National Military Medical Center. Participants completed a blood draw, neuropsychological assessment, and diffusion tensor imaging (General Electric 3T) of the whole brain. From 20 neuropsychological test scores, five cognitive domain scores were computed. Measures of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were generated for 18 regions of interest (ROIs). There was no relationship found between the plasma biomarkers and neurocognitive performance in any of the three TBI groups (all ps >0.05; all R² changes <0.146). Although not reaching statistical significance after correction for multiple comparisons, higher tau and Aβ42 tended to be related to higher FA and lower MD, RD, and AD in patients with a history of moderate, severe, or penetrating TBI. There was no consistent relationship between either of the biomarkers and white matter integrity in the complicated and uncomplicated mild TBI groups. In addition, there was no significant relationship between the biomarkers and age, education, sex, race, bodily injury severity, time since injury, TBI severity, or number of TBIs (all ps >0.15). Future investigation in larger samples of moderate, severe, and penetrating TBI are needed. Other plasma biomarkers, including phosphorylated tau, exosomal tau, and interleukin-10, may be more promising measures to use in the diagnosis, management, and treatment of TBI.

Limited Prediction of Performance Validity Using Embedded Validity Scales of the Neurobehavioral Symptom Inventory in an mTBI Veteran Sample

OBJECTIVE

To test embedded symptom validity scales of the Neurobehavioral Symptom Inventory (NSI) as predictors of performance validity.

SETTING

A Veterans Affairs Level II TBI/Polytrauma outpatient care unit in the Midwestern United States.

PARTICIPANTS

Veterans with a history of mild traumatic brain injury undergoing neuropsychological assessment as part of their routine care within the TBI/Polytrauma clinic.

DESIGN

Retrospective analysis of the existing clinical data.

MAIN MEASURES

The NSI, the b Test, Test of Memory Malingering, Reliable Digit Span, California Verbal Learning Test-II Forced Choice.

RESULTS

Embedded NSI validity scales were positively correlated with number of performance validity test failures. Participants identified as invalid responders scored higher on embedded NSI validity scales than participants identified as valid responders. Using receiver operating characteristic analysis, the embedded NSI validity scales showed poor sensitivity and specificity for invalid responding using previously published cutoff scores. Only 1 scale differentiated valid from invalid responders better than chance.

CONCLUSION

The embedded NSI validity scales' usefulness in predicting invalid neuropsychological performance validity was limited in this sample. Continued measurement of both symptom and performance validity in clinical settings involving traumatic brain injury treatment is recommended, as the present results support the existing research suggesting symptom validity tests and performance validity tests tap into related but ultimately distinct constructs.

Exposure Therapy and Simultaneous Repetitive Transcranial Magnetic Stimulation: A Controlled Pilot Trial for the Treatment of Posttraumatic Stress Disorder

OBJECTIVES

This is a small preliminary but novel study assessing the feasibility of repetitive transcranial magnetic stimulation (rTMS) delivery to veterans with posttraumatic stress disorder (PTSD) while they simultaneously receive prolonged exposure (PE) therapy.

METHODS

A prospective, randomized, double-blinded, active sham-controlled design combined weekly sessions of rTMS and standard PE at the Veterans Administration Hospital. Eight adult patients received a full course of protocol-driven PE therapy and were randomly assigned to receive either rTMS or sham rTMS. Repetitive transcranial magnetic stimulation was delivered to the right or left prefrontal cortex with a figure-eight solid core coil at 120% motor threshold, 10 Hz, 5-second train duration, and 10-second intertrain interval for 30 minutes (6000 pulses) weekly for 5 weeks (30,000 stimuli).

RESULTS

Of the 12 veterans consented, 8 completed the study treatment protocol. The dropout rate was 34%, roughly equivalent to the pooled average dropout rates observed in traditional PE therapy with Operation Enduring Freedom/Operation Iraqi Freedom veterans with PTSD, suggesting that veterans had no difficulty tolerating the addition of rTMS to PE therapy and that this is a feasible study design for larger trials in the future. Clinician-Administered PTSD Symptom scores reflected a general nonsignificant trend toward improvement, and subjects with comorbid major depression appeared to experience significant antidepressant benefit with treatment despite the fact that the doses used in this protocol were much smaller than those used to treat patients with major depressive disorder.

CONCLUSIONS

This pilot study demonstrates the safety and feasibility of rTMS delivery to PTSD patients while they simultaneously receive PE. This unique approach to the treatment of PTSD highlights the need for further studies with larger sample sizes to assess treatment outcomes.

The utility of clinical criteria in patients with chronic traumatic encephalopathy

BACKGROUND

Repetitive traumatic brain injury (TBI) is associated with chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disorder characterized by Alzheimer-like changes in the brain. CTE has been defined through neuropathological findings among deceased athletes and others exposed to repetitive TBI, but to date there are no definitive clinical criteria for CTE.

OBJECTIVE

To evaluate the utility of currently proposed clinical criteria for CTE and suggest improvements.

METHODS

We describe two well-characterized patients referred for evaluation of CTE and apply the four major proposed criteria for CTE. These criteria were further assessed in a cohort of patients referred to a neurobehavior clinic with or without a history of TBI.

RESULTS

Without a CTE biomarker, the current criteria were of limited utility when applied to the two patient and the Neurobehavior cohort. Six items were extracted as potentially improving the clinical diagnosis of CTE: length of exposure to head impacts, a progressive course, specific psychiatric symptoms, frontal-executive dysfunction, parkinsonism and tremors, and targeted findings on neuroimaging.

CONCLUSIONS

The prevention and neurorehabilitation of CTE depends on clinical diagnosis, but, without a biomarker, the clinical diagnosis of CTE remains difficult. This report suggests that clinical criteria for CTE may be greatly improved with emphasis on several critical historical and clinical correlates of CTE.

Associations between neuropsychiatric and health status outcomes in individuals with probable mTBI

Mild traumatic brain injury (mTBI) is a common occurrence, and may impact distal outcomes in a subgroup of individuals. Improved characterization of health outcomes and identification of factors associated with poor outcomes is needed to better understand the impact of mTBI, particularly in those with co-occurring posttraumatic stress disorder (PTSD). Participants in a data repository of the Injury and Traumatic Stress (INTRuST) Clinical Consortium (n = 625) completed functional disability [FD] and health-related quality of life [HRQOL] questionnaires, and a subset completed a neuropsychological assessment. FD and HRQOL were compared among participants with probable mTBI (mTBI), probable mTBI with PTSD (mTBI/PTSD), and health comparison participants (HC). Associations between symptoms, neuropsychological performance, and health outcomes were examined in those with probable mTBI with and without PTSD (n = 316). Individuals in the mTBI/PTSD group endorsed poorer health outcomes than those in the mTBI group, who endorsed poorer outcomes than those in the HC group. Individuals in either mTBI group performed worse than those in the HC on verbal learning and memory and psychomotor speed. Health outcomes were correlated with mental health and postconcussive symptoms, as well as neuropsychological variables. mTBI may adversely impact self-reported health, with the greatest effect observed in individuals with co-occurring mTBI/PTSD.

Reference values for the Balance Error Scoring System as measured by the Tekscan MobileMat™ in a physically active population

OBJECTIVES

The Balance Error Scoring System (BESS) is commonly used to measure postural stability; however, it has demonstrated inconsistent reliability values when administered by humans. The Tekscan MobileMat™ was developed to automate the assessment of BESS errors and eliminate rater subjectivity. The objective of this study was to report reference values for the BESS, as measured by the MobileMat™, and examine the effect of sex, concussion history, and competitive sport level on BESS performance.

METHODS

Four hundred and forty participants performed the BESS on the MobileMat™. Participants were asked to maintain each stance with their eyes closed for 20 s. The MobileMat™ was used to quantify the number of errors.

RESULTS

Concussion history (p = 0.279-0.979) and competitive sport level (p = 0.422-0.979) did not affect BESS performance. Males performed significantly better than females for the single-limb foam stance (p = 0.032). No sex differences were detected for the other BESS stances or BESS total score (p = 0.067-0.744).

CONCLUSIONS

Previously reported reference values in collegiate athletes and adolescents were slightly higher thus highlighting the value in establishing population norms and in developing new technologies to objectively quantify BESS performance. Furthermore, sex, concussion history, and competitive sport level do not appear to influence BESS performance as measured by the MobileMat™.

Blast-induced "PTSD": Evidence from an animal model

A striking observation among veterans returning from the recent conflicts in Iraq and Afghanistan has been the co-occurrence of blast-related mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD). PTSD and mTBI might coexist due to additive effects of independent psychological and physical traumas experienced in a war zone. Alternatively blast injury might induce PTSD-related traits or damage brain structures that mediate responses to psychological stressors, increasing the likelihood that PTSD will develop following a subsequent psychological stressor. Rats exposed to repetitive low-level blasts consisting of three 74.5 kPa exposures delivered once daily for three consecutive days develop a variety of anxiety and PTSD-related behavioral traits that are present for at least 9 months after blast exposure. A single predator scent challenge delivered 8 months after the last blast exposure induces additional anxiety-related changes that are still present 45 days later. Because the blast injuries occur under general anesthesia, it appears that blast exposure in the absence of a psychological stressor can induce chronic PTSD-related traits. The reaction to a predator scent challenge delivered many months after blast exposure suggests that blast exposure in addition sensitizes the brain to react abnormally to subsequent psychological stressors. The development of PTSD-related behavioral traits in the absence of a psychological stressor suggests the existence of blast-induced "PTSD". Findings that PTSD-related behavioral traits can be reversed by BCI-838, a group II metabotropic glutamate receptor antagonist offers insight into pathogenesis and possible treatment options for blast-related brain injury. This article is part of the Special Issue entitled "Novel Treatments for Traumatic Brain Injury".

Training in Goal-Oriented Attention Self-Regulation Improves Executive Functioning in Veterans with Chronic Traumatic Brain Injury

Deficits in executive control functions are some of the most common and disabling consequences of both military and civilian brain injury. However, effective interventions are scant. The goal of this study was to assess whether cognitive rehabilitation training that was successfully applied in chronic civilian brain injury would be effective for military veterans with traumatic brain injury (TBI). In a prior study, participants with chronic acquired brain injury significantly improved after training in Goal-Oriented Attentional Self-Regulation (GOALS) on measures of attention/executive function, functional task performance, and goal-directed control over neural processing on functional magnetic resonance imaging. The objective of this study was to assess effects of GOALS training in veterans with chronic TBI. A total of 33 veterans with chronic TBI and executive difficulties in their daily life completed either 5 weeks of manualized GOALS training or Brain-Health Education (BHE) matched by time and intensity. Evaluator-blinded assessments at baseline and post-training included neuropsychological and complex functional task performance and self-report measures of emotional regulation. After GOALS, but not BHE training, participants significantly improved from baseline on primary outcome measures of Overall Complex Attention/Executive Function composite neuropsychological performance score (F = 7.10, p = 0.01; partial η² = 0.19), and on overall complex functional task performance (Goal Processing Scale Overall Performance; F = 6.92, p = 0.01, partial η² = 0.20). Additionally, post-GOALS participants indicated significant improvement on emotional regulation self-report measures (Profile of Mood States Confusion Score; F = 6.05, p = 0.02, partialη² = 0.20). Training in attentional self-regulation applied to participant-defined goals may improve cognitive functioning in veterans with chronic TBI. Attention regulation training may not only impact executive control functioning in real-world complex tasks, but also may improve emotional regulation and functioning. Implications for treatment of veterans with TBI are discussed.

Preclinical modelling of militarily relevant traumatic brain injuries: Challenges and recommendations for future directions

As a follow-up to the 2008 state-of-the-art (SOTA) conference on traumatic brain injuries (TBIs), the 2015 event organized by the United States Department of Veterans Affairs (VA) Office of Research and Development (ORD) analysed the knowledge gained over the last 7 years as it relates to basic scientific methods, experimental findings, diagnosis, therapy, and rehabilitation of TBIs and blast-induced neurotraumas (BINTs). The current article summarizes the discussions and recommendations of the scientific panel attending the Preclinical Modeling and Therapeutic Development Workshop of the conference, with special emphasis on factors slowing research progress and recommendations for ways of addressing the most significant pitfalls.

The Unique Health Needs of Post-9/11 U.S. Veterans

This article applies a hazard-based approach to the identification of physical, mental, and psychosocial health needs of post-9/11 veterans. The weaponry, survival, and population of servicemen and women by the military have evolved over time, particularly during the post-9/11 era. It is evident that military hazards and potential exposures vary depending on not only the deployment era but also the specific location and role. Many individual factors may affect the development of health problems. Recent evidence-based literature about post-9/11 veterans' long-term complex health issues is summarized, so occupational health nurses can advocate for the provision of veteran-sensitive care.

Screening for Remote History of Mild Traumatic Brain Injury in VHA: A Critical Literature Review

OBJECTIVE

The authors reviewed the existing literature on the Veterans Health Administration's (VHA's) traumatic brain injury (TBI) screening and evaluation program to provide a qualitative synthesis and critical review of results focusing on the psychometric properties of the screen.

METHODS

All studies of the VHA's screening and evaluation process were reviewed, both those involving primary data collection and those relying upon VHA data. Diagnostic statistics were summarized and also recalculated on the basis of a positive screening rate of 20%, the observed rate within the VHA, and an estimated population prevalence of TBI of 15% within the Department of Veterans Affairs (VHA).

RESULTS

The TBI screen within the VHA is administered to nearly every eligible patient. The majority of clinical presentations are deemed to be due to mental health and/or a combination of mental health and TBI factors. The screen has good internal consistency, variable test-retest reliability, and questionable validity, with poor agreement between the TBI screen and criterion standards overall. Studies based on nonrepresentative samples reported high sensitivity. Assuming the VHA's TBI screening rate of 20% in a hypothetical sample, sensitivity is poor (the screen misses 30%-60% of TBI cases). However, specificity remains adequate. Studies based on samples with high rates of TBI reported much higher positive predictive values (and slightly lower negative predictive values) than those observed when a hypothetical TBI prevalence of 15% was used.

CONCLUSION

Questions remain about the validity of the TBI screen. Future research should address the utility of screening for TBI.

Postconcussive Symptoms, PTSD, and Medical Disease Burden in Treatment-Seeking OEF/OIF/OND Veterans

INTRODUCTION

The most common psychological and cognitive sequelae associated with deployments to Afghanistan (Operation Enduring Freedom) and Iraq (Operation Iraqi Freedom) are mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD). High rates of PTSD are often observed among Veterans with a history of mTBI, and persistent postconcussive symptoms commonly endorsed after mTBI are known to be associated with PTSD. Therefore, this study examined whether PTSD mediates relations between postconcussive symptoms and 2 indices of medical disease burden: 1) the number of disease categories positive for a diagnosis, or system disease burden, and 2) total number of physical diagnoses, or cumulative disease burden.

MATERIALS AND METHODS

Participants were 91 Operation Enduring Freedom/Operation Iraqi Freedom/Operation New Dawn Veterans seeking treatment at a Veterans Affairs Medical Center who screened positive for mTBI and later attended a follow-up Polytrauma clinic evaluation for neuropsychiatric assessment. Medical records were reviewed for a history of mTBI, postconcussive symptoms, and physician diagnoses, which were used to derive system and cumulative disease burden variables. Mediation was tested using bootstrapping procedures. Participants provided written informed consent and all study procedures were approved by both the VA and university institutional review boards.

RESULTS

Postconcussive symptoms (r = 0.53) and PTSD symptoms (r = 0.32) were both associated with cumulative disease burden. Only postconcussive symptoms were associated with system disease burden (r = 0.32). Results of our follow-up mediation analysis suggest that PTSD did not mediate relations between postconcussive symptoms and cumulative disease burden (bootstrap coefficient = -0.02, 95% confidence interval [-0.05 to 0.01]).

CONCLUSION

These findings join an emerging body of literature suggesting that postconcussive symptoms have a direct impact on Veterans' health above and beyond the effects of PTSD. Strengths of this study include the use of objective, clinician-diagnosed medical conditions as an indicator of health, whereas limitations include the use of self-report measures to assess postconcussive and PTSD symptoms. This study underscores the need for more original research on the impact of mTBI on the long-term health and readjustment of returning Veterans. Furthermore, this study highlights the need for additional research on the psychosocial and pathophysiological mechanisms underlying the link between mTBI and poor health.

PTSD-Related Behavioral Traits in a Rat Model of Blast-Induced mTBI Are Reversed by the mGluR2/3 Receptor Antagonist BCI-838

Battlefield blast exposure related to improvised explosive devices (IEDs) has become the most common cause of traumatic brain injury (TBI) in the recent conflicts in Iraq and Afghanistan. Mental health problems are common after TBI. A striking feature in the most recent veterans has been the frequency with which mild TBI (mTBI) and posttraumatic stress disorder (PTSD) have appeared together, in contrast to the classical situations in which the presence of mTBI has excluded the diagnosis of PTSD. However, treatment of PTSD-related symptoms that follow blast injury has become a significant problem. BCI-838 (MGS0210) is a Group II metabotropic glutamate receptor (mGluR2/3) antagonist prodrug, and its active metabolite BCI-632 (MGS0039) has proneurogenic, procognitive, and antidepressant activities in animal models. In humans, BCI-838 is currently in clinical trials for refractory depression and suicidality. The aim of the current study was to determine whether BCI-838 could modify the anxiety response and reverse PTSD-related behaviors in rats exposed to a series of low-level blast exposures designed to mimic a human mTBI or subclinical blast exposure. BCI-838 treatment reversed PTSD-related behavioral traits improving anxiety and fear-related behaviors as well as long-term recognition memory. Treatment with BCI-838 also increased neurogenesis in the dentate gyrus (DG) of blast-exposed rats. The safety profile of BCI-838 together with the therapeutic activities reported here, make BCI-838 a promising drug for the treatment of former battlefield Warfighters suffering from PTSD-related symptoms following blast-induced mTBI.

Bibliometric analysis of military trauma publications: 2000-2016

INTRODUCTION

Bibliometric tools can be used to identify the authors, topics and research institutions that have made the greatest impact in a field of medicine. The aim of this research was to analyse military trauma publications over the last 16 years of armed conflict in order to highlight the most important lessons that have translated into civilian practice and military doctrine as well as identify emerging areas of importance.

METHODS

A systematic search of research published between January 2000 and December 2016 was conducted using the Thompson Reuters Web of Science database. Both primary evidence and review publications were included. Results were categorised according to relevance and topic and the 30 most cited publications were reviewed in full. The h-index, impact factors, citation counts and citation analysis were used to evaluate results.

RESULTS

A plateau in the number of annual publications on military trauma was found, as was a shift away from publications on wound and mortality epidemiology to publications on traumatic brain injury (TBI), neurosurgery or blast injury to the head. Extensive collaboration networks exist between highly contributing authors and institutions, but less collaboration between authors from different countries. The USA produced the majority of recent publications, followed by the UK, Germany and Israel.

CONCLUSIONS

In recent years, the number of publications on TBI, neurosurgery or blast injury to the head has increased. It is likely that the lessons of recent conflicts will continue to influence civilian medical practice, particularly regarding the long-term effects of blast-related TBI.

Hyperarousal Symptoms Explain the Relationship Between Cognitive Complaints and Working Memory Performance in Veterans Seeking PTSD Treatment

OBJECTIVE

Comorbidity and symptom overlap between traumatic brain injury and posttraumatic stress disorder (PTSD) in veterans returning from deployment present challenges with respect to differential diagnosis and treatment. Both conditions frequently manifest with attention and working memory deficits, though the underlying neuropsychological basis differs. This study evaluated whether hyperarousal symptoms explain the relationship between subjective and objective measures of cognition in a veteran sample.

PARTICIPANTS AND PROCEDURES

One-hundred three veterans completed the military version of the PTSD Checklist (PCL), the Neurobehavioral Symptom Inventory, and the Wechsler Memory Scale, 3rd edition digit span task with adequate effort.

RESULTS

Hierarchical regression suggested that hyperarousal, but not other PTSD symptoms, explained the relationship between neurobehavioral symptoms and cognitive functioning. This relationship was present regardless of whether veterans met full PTSD diagnostic criteria or screened positive on a traumatic brain injury screener and was robust to other moderators.

CONCLUSION

These findings highlight the importance of considering traumatic brain injury and PTSD symptom overlap, particularly the relationship between hyperarousal symptoms and attention and working memory deficits, in conceptualizing cases and treatment planning.

Identifying disease foci from static and dynamic effective connectivity networks: Illustration in soldiers with trauma

Brain connectivity studies report group differences in pairwise connection strengths. While informative, such results are difficult to interpret since our understanding of the brain relies on region-based properties, rather than on connection information. Given that large disruptions in the brain are often caused by a few pivotal sources, we propose a novel framework to identify the sources of functional disruption from effective connectivity networks. Our approach integrates static and time-varying effective connectivity modeling in a probabilistic framework, to identify aberrant foci and the corresponding aberrant connectomics network. Using resting-state fMRI, we illustrate the utility of this novel approach in U.S. Army soldiers (N = 87) with posttraumatic stress disorder (PTSD), mild traumatic brain injury (mTBI) and combat controls. Additionally, we employed machine-learning classification to identify those significant connectivity features that possessed high predictive ability. We identified three disrupted foci (middle frontal gyrus [MFG], insula, hippocampus), and an aberrant prefrontal-subcortical-parietal network of information flow. We found the MFG to be the pivotal focus of network disruption, with aberrant strength and temporal-variability of effective connectivity to the insula, amygdala and hippocampus. These connectivities also possessed high predictive ability (giving a classification accuracy of 81%); and they exhibited significant associations with symptom severity and neurocognitive functioning. In summary, dysregulation originating in the MFG caused elevated and temporally less-variable connectivity in subcortical regions, followed by a similar effect on parietal memory-related regions. This mechanism likely contributes to the reduced control over traumatic memories leading to re-experiencing, hyperarousal and flashbacks observed in soldiers with PTSD and mTBI. Hum Brain Mapp 39:264-287, 2018. © 2017 Wiley Periodicals, Inc.

What is the Relationship of Traumatic Brain Injury to Dementia?

There is a long history linking traumatic brain injury (TBI) with the development of dementia. Despite significant reservations, such as recall bias or concluding causality for TBI, a summary of recent research points to several conclusions on the TBI-dementia relationship. 1) Increasing severity of a single moderate-to-severe TBI increases the risk of subsequent Alzheimer's disease (AD), the most common type of dementia. 2) Repetitive, often subconcussive, mild TBIs increases the risk for chronic traumatic encephalopathy (CTE), a degenerative neuropathology. 3) TBI may be a risk factor for other neurodegenerative disorders that can be associated with dementia. 4) TBI appears to lower the age of onset of TBI-related neurocognitive syndromes, potentially adding "TBI cognitive-behavioral features". The literature further indicates several specific risk factors for TBI-associated dementia: 5) any blast or blunt physical force to the head as long as there is violent head displacement; 6) decreased cognitive and/or neuronal reserve and the related variable of older age at TBI; and 7) the presence of apolipoprotein E ɛ4 alleles, a genetic risk factor for AD. Finally, there are neuropathological features relating TBI with neurocognitive syndromes: 8) acute TBI results in amyloid pathology and other neurodegenerative proteinopathies; 9) CTE shares features with neurodegenerative dementias; and 10) TBI results in white matter tract and neural network disruptions. Although further research is needed, these ten findings suggest that dose-dependent effects of violent head displacement in vulnerable brains predispose to dementia; among several potential mechanisms is the propagation of abnormal proteins along damaged white matter networks.

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

BACKGROUND

It is unknown how traumatic brain injury (TBI) increases risk for posttraumatic stress disorder (PTSD). One potential mechanism is via alteration of fear-learning processes that could affect responses to trauma memories and cues. We utilized a prospective, longitudinal design to determine if TBI is associated with altered fear learning and extinction, and if fear processing mediates effects of TBI on PTSD symptom change.

METHODS

Eight hundred fifty two active-duty Marines and Navy Corpsmen were assessed before and after deployment. Assessments included TBI history, PTSD symptoms, combat trauma and deployment stress, and a fear-potentiated startle task of fear acquisition and extinction. Startle response and self-reported expectancy and anxiety served as measures of fear conditioning, and PTSD symptoms were measured with the Clinician-Administered PTSD Scale.

RESULTS

Individuals endorsing "multiple hit" exposure (both deployment TBI and a prior TBI) showed the strongest fear acquisition and highest fear expression compared to groups without multiple hits. Extinction did not differ across groups. Endorsing a deployment TBI was associated with higher anxiety to the fear cue compared to those without deployment TBI. The association of deployment TBI with increased postdeployment PTSD symptoms was mediated by postdeployment fear expression when recent prior-TBI exposure was included as a moderator. TBI associations with increased response to threat cues and PTSD symptoms remained when controlling for deployment trauma and postdeployment PTSD diagnosis.

CONCLUSIONS

Deployment TBI, and multiple-hit TBI in particular, are associated with increases in conditioned fear learning and expression that may contribute to risk for developing PTSD symptoms.

Cerebral Salt-Wasting Syndrome: Diagnosis by Urine Sodium Excretion

BACKGROUND

Cerebral salt-wasting syndrome (CSWS) was initially described over 60 years ago in hyponatremic patients with a cerebral lesion. However, the diagnostic criteria for CSWS have not been fully established. Thus, when hyponatremia is observed in patients with CSWS, they may be misdiagnosed as having the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Thus, it is critical to differentiate between these 2 conditions because their treatments are diametrically opposed.

MATERIALS AND METHODS

We carried out a retrospective study of 45 patients with CSWS and compared them to 60 normonatremic control patients, and 28 patients with SIADH. All patients had their 24-hour urine volumes and sodium (Na) excretion measured.

RESULTS

In patients with CSWS, urinary Na excretion was 394 ± 369mmol/24 hours and urinary volume was 2,603 ± 996mL/24 hours; both values significantly greater than in controls (P < 0.01). By contrast, in patients with SIADH, the urine Na excretion was only 51 ± 25mmol/24 hours and urine volume was 745 ± 298mL/24 hours; values significantly lower than in patients with CSWS (P < 0.01).

CONCLUSIONS

CSWS was diagnosed in patients with cerebral lesion who had (1) symptomatic hyponatremia, (2) urine Na excretion 2 standard deviations above controls and (3) increased urine volume. Patients with SIADH also had symptomatic hyponatremia but, in contrast to patients with CSWS, they had decreased Na excretion and urine volume. Thus urine Na excretion and volume are very important for diagnosing the cause of hyponatremia in patients with cerebral lesions.

Consistency of Self-Reported Neurocognitive Symptoms, Post-Traumatic Stress Disorder Symptoms, and Concussive Events From End of First Deployment to Veteran Health Administration Comprehensive Traumatic Brain Injury Evaluation by Operations Enduring Freedom/Iraqi Freedom/New Dawn Veterans

Objective

This study examined the consistency of self-reported symptoms and concussive events in combat veterans who reported experiencing concussive events.

Method

One hundred and forty, single deployed, Operation Enduring Freedom, Operation Iraqi Freedom and Operation New Dawn combat veterans with Veteran Health Administration (VHA) Comprehensive Traumatic Brain Injury Evaluations (CTBIE) and no post-deployment head injury were examined to assess consistency of self-reported (a) traumatic brain injury (TBI)-related symptoms, (b) post-traumatic stress disorder (PTSD)-related symptoms, and (c) TBI-related concussive events from soon after deployment to time of VHA CTBIE.

Results

Compared to their self-report of symptoms and traumatic events at the time of their Post-Deployment Health Assessment, at the time of their comprehensive VHA evaluation, subjects reported significantly greater impairment in concentration, decision making, memory, headache, and sleep. In addition, although half the subjects denied any PTSD symptoms post-deployment, approximately three quarters reported experiencing all four PTSD screening symptoms near the time of the VHA CTBIEs. At the latter time, subjects also reported significantly more TBI-related concussive events, as well as more post-concussive sequelae such as loss of consciousness immediately following these concussive events. Finally, although 84% reported a level of impairment so severe as to render all but the simplest activity doable, the vast majority simultaneously reported working and/or attending college.

Conclusions

These findings raise questions regarding the accuracy of veteran self-report of both near and distant traumatic events, and argue for the inclusion of contemporaneous Department of Defense (DOD) records in veteran assessment and treatment planning.

Compromised hippocampus-striatum pathway as a potential imaging biomarker of mild-traumatic brain injury and posttraumatic stress disorder

OBJECTIVES

Military service members risk acquiring posttraumatic stress disorder (PTSD) and mild-traumatic brain injury (mTBI), with high comorbidity. Owing to overlapping symptomatology in chronic mTBI or postconcussion syndrome (PCS) and PTSD, it is difficult to assess the etiology of a patient's condition without objective measures. Using resting-state functional MRI in a novel framework, we tested the hypothesis that their neural signatures are characterized by functionally hyperconnected brain regions which are less variable over time. Additionally, we predicted that such connectivities possessed the highest ability in predicting the diagnostic membership of a novel subject (top-predictors) in addition to being statistically significant.

METHODS

U.S. Army Soldiers (N = 87) with PTSD and comorbid PCS + PTSD were recruited along with combat controls. Static and dynamic functional connectivities were evaluated. Group differences were obtained in accordance with our hypothesis. Machine learning classification (MLC) was employed to determine top predictors.

RESULTS

From whole-brain connectivity, we identified the hippocampus-striatum connectivity to be significantly altered in accordance with our hypothesis. Diffusion tractography revealed compromised white-matter integrity between aforementioned regions only in the PCS + PTSD group, suggesting a structural etiology for the PCS + PTSD group rather than being an extreme subset of PTSD. Employing MLC, connectivities provided worst-case accuracy of 84% (9% more than psychological measures). Additionally, the hippocampus-striatum connectivities were found to be top predictors and thus a potential biomarker of PTSD/mTBI.

CONCLUSIONS

PTSD/mTBI are associated with hippocampal-striatal hyperconnectivity from which it is difficult to disengage, leading to a habit-like response toward episodic traumatic memories, which fits well with behavioral manifestations of combat-related PTSD/mTBI. Hum Brain Mapp 38:2843-2864, 2017. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

TS, Traynham S, Knight DC. Exploring the Neurocircuitry Underpinning Predictability of Threat in Soldiers with PTSD Compared to Deployment Exposed Controls

BACKGROUND

Prior work examining emotional dysregulation observed in posttraumatic stress disorder (PTSD) has primarily been limited to fear-learning processes specific to anticipation, habituation, and extinction of threat. In contrast, the response to threat itself has not been systematically evaluated.

OBJECTIVE

To explore potential disruption in fear conditioning neurocircuitry in service members with PTSD, specifically in response to predictable versus unpredictable threats.

METHOD

In the current study, active-duty U.S. Army soldiers with (PTSD group; n = 38) and without PTSD (deployment-exposed controls; DEC; n = 40), participated in a fear-conditioning study in which threat predictability was manipulated by presenting an aversive unconditioned stimulus (UCS) that was either preceded by a conditioned stimulus (i.e., predictable) or UCS alone (i.e., unpredictable). Threat expectation, skin conductance response (SCR), and functional magnetic resonance imaging (fMRI) signal to predictable and unpredictable threats (i.e., UCS) were assessed.

RESULTS

Both groups showed greater threat expectancy and diminished threat-elicited SCRs to predictable compared to unpredictable threat. Significant group differences were observed within the amygdala, hippocampus, insula, and superior and middle temporal gyri. Contrary to our predictions, the PTSD group showed a diminished threat-related response within each of these brain regions during predictable compared to unpredictable threat, whereas the DEC group showed increased activation.

CONCLUSION

Although, the PTSD group showed greater threat-related diminution, hypersensitivity to unpredictable threat cannot be ruled out. Furthermore, pre-trauma, trait-like factors may have contributed to group differences in activation of the neurocircuitry underpinning fear conditioning.

Exposure to a Predator Scent Induces Chronic Behavioral Changes in Rats Previously Exposed to Low-level Blast: Implications for the Relationship of Blast-Related TBI to PTSD

Blast-related mild traumatic brain injury (mTBI) has been unfortunately common in veterans who served in the recent conflicts in Iraq and Afghanistan. The postconcussion syndrome associated with these mTBIs has frequently appeared in combination with post-traumatic stress disorder (PTSD). The presence of PTSD has complicated diagnosis, since clinically, PTSD and the postconcussion syndrome of mTBI have many overlapping symptoms. In particular, establishing how much of the symptom complex can be attributed to the psychological trauma associated with PTSD in contrast to the physical injury of traumatic brain injury has proven difficult. Indeed, some have suggested that much of what is now being called blast-related postconcussion syndrome is better explained by PTSD. The relationship between the postconcussion syndrome of mTBI and PTSD is complex. Association of the two disorders might be viewed as additive effects of independent psychological and physical traumas suffered in a war zone. However, we previously found that rats exposed to repetitive low-level blast exposure in the absence of a psychological stressor developed a variety of anxiety and PTSD-related behavioral traits that were present months following the last blast exposure. Here, we show that a single predator scent challenge delivered 8 months after the last blast exposure induces chronic anxiety related changes in blast-exposed rats that are still present 45 days later. These observations suggest that in addition to independently inducing PTSD-related traits, blast exposure sensitizes the brain to react abnormally to a subsequent psychological stressor. These studies have implications for conceptualizing the relationship between blast-related mTBI and PTSD and suggest that blast-related mTBI in humans may predispose to the later development of PTSD in reaction to subsequent psychological stressors.