A brief overview of traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) within the Department of Defense

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Military-related mild traumatic brain injury: clinical characteristics, advanced neuroimaging, and molecular mechanisms

Mild traumatic brain injury (mTBI) is a significant health burden among military service members. Although mTBI was once considered relatively benign compared to more severe TBIs, a growing body of evidence has demonstrated the devastating neurological consequences of mTBI, including chronic post-concussion symptoms and deficits in cognition, memory, sleep, vision, and hearing. The discovery of reliable biomarkers for mTBI has been challenging due to under-reporting and heterogeneity of military-related mTBI, unpredictability of pathological changes, and delay of post-injury clinical evaluations. Moreover, compared to more severe TBI, mTBI is especially difficult to diagnose due to the lack of overt clinical neuroimaging findings. Yet, advanced neuroimaging techniques using magnetic resonance imaging (MRI) hold promise in detecting microstructural aberrations following mTBI. Using different pulse sequences, MRI enables the evaluation of different tissue characteristics without risks associated with ionizing radiation inherent to other imaging modalities, such as X-ray-based studies or computerized tomography (CT). Accordingly, considering the high morbidity of mTBI in military populations, debilitating post-injury symptoms, and lack of robust neuroimaging biomarkers, this review (1) summarizes the nature and mechanisms of mTBI in military settings, (2) describes clinical characteristics of military-related mTBI and associated comorbidities, such as post-traumatic stress disorder (PTSD), (3) highlights advanced neuroimaging techniques used to study mTBI and the molecular mechanisms that can be inferred, and (4) discusses emerging frontiers in advanced neuroimaging for mTBI. We encourage multi-modal approaches combining neuropsychiatric, blood-based, and genetic data as well as the discovery and employment of new imaging techniques with big data analytics that enable accurate detection of post-injury pathologic aberrations related to tissue microstructure, glymphatic function, and neurodegeneration. Ultimately, this review provides a foundational overview of military-related mTBI and advanced neuroimaging techniques that merit further study for mTBI diagnosis, prognosis, and treatment monitoring.

High risk and low prevalence diseases: Blast injuries

INTRODUCTION

Blast injury is a unique condition that carries a high rate of morbidity and mortality, often with mixed penetrating and blunt injuries.

OBJECTIVE

This review highlights the pearls and pitfalls of blast injuries, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Explosions may impact multiple organ systems through several mechanisms. Patients with suspected blast injury and multisystem trauma require a systematic evaluation and resuscitation, as well as investigation for injuries specific to blast injuries. Blast injuries most commonly affect air-filled organs but can also result in severe cardiac and brain injury. Understanding blast injury patterns and presentations is essential to avoid misdiagnosis and balance treatment of competing interests of patients with polytrauma. Management of blast victims can also be further complicated by burns, crush injury, resource limitation, and wound infection. Given the significant morbidity and mortality associated with blast injury, identification of various injury patterns and appropriate management are essential.

CONCLUSIONS

An understanding of blast injuries can assist emergency clinicians in diagnosing and managing this potentially deadly disease.

MicroRNAs as biomarker and novel therapeutic target for posttraumatic stress disorder in Veterans

Posttraumatic stress disorder (PTSD) is a common psychiatric disorder for military Veterans, characterized by hyperarousal, intrusive thoughts, flashbacks, hypervigilance, and distress after experiencing traumatic events. Some of the known physiological effects of PTSD include hypothalamic-pituitary-adrenal (HPA)-axis imbalance, a cortical function resulting in neuronal deficit and changes in behavior. Moreover, excessive discharge of inflammatory molecules and a dysregulated immune system are implicated in the pathophysiology of PTSD. Due to complex nature of this disorder, the biological underpinnings of PTSD remain inexplicable. Investigating novel biomarkers to understanding the pathogenesis of PTSD may reflect the underlying molecular network for therapeutic use and treatment. Circulatory microRNAs (miRNAs) and exosomes are evolving biomarkers that have shown a key role in psychiatric and neurological disorders including PTSD. Given the unique nature of combat trauma, as well as evidence that a large portion of Veterans do not benefit from frontline treatments, focus on veterans specifically is warranted. In the present review, we delineate the identification and role of several miRNAs in PTSD among veterans. An association of miRNA with HPA-axis regulation through FKBP5, a key modulator in PTSD is discussed as an emerging molecule in psychiatric diseases. We conclude that miRNAs may be used as circulatory biomarker detection in Veterans with PTSD.

An Innovative Approach for Graduate Education for Psychiatric Nurse Practitioners

A major transformation in nurse practitioner (NP) education is the emergence of post graduate residencies; their foci include (a) educating NPs in population health; (b) increasing clinical proficiency; and (c) incorporating quality and safety into practice. We describe a psychiatric NP residency program supported by an academic-practice partnership, known as the Veterans Affairs Nursing Academic Partnership for Graduate Education (VANAP-GE) between the Birmingham Veterans Administration Medical Center (BVAMC) and the University of Alabama at Birmingham (UAB) School of Nursing (SON) for a population of Veterans with complex mental and physical health needs. Topics which are covered include risks of suicide among Veterans, post-traumatic stress disorder, depressive and anxiety disorders, and substance use disorders. During this one-year traineeship during the first year after NP certification, residents engage in development of crucial skills for improving the future of U.S. health care. All residents are newly licensed PMHNPs, but some are also pursuing DNP degrees. For residents who are simultaneously enrolled in BSN to DNP programs, the additional clinical training afforded by NP residency education provides a natural laboratory for their projects with foci of quality and safety, leadership, and clinical scholarship. Reduction in NP turnover as well as cost savings of orientation and recruitment are significant benefits for the practice partner with zero vacancies since the partnership's inception. These multiple successes predict increased establishment of residencies as viable post graduate pathways for NPs.

Cognitive Effects of Astaxanthin Pretreatment on Recovery From Traumatic Brain Injury

Traumatic brain injury (TBI), caused by mechanical impact to the brain, is a leading cause of death and disability among young adults, with slow and often incomplete recovery. Preemptive treatment strategies may increase the injury resilience of high-risk populations such as soldiers and athletes. In this work, the xanthophyll carotenoid Astaxanthin was examined as a potential nutritional preconditioning method in mice (sabra strain) to increase their resilience prior to TBI in a closed head injury (CHI) model. The effect of Astaxanthin pretreatment on heat shock protein (HSP) dynamics and functional outcome after CHI was explored by gavage or free eating (in pellet form) for 2 weeks before CHI. Assessment of neuromotor function by the neurological severity score (NSS) revealed significant improvement in the Astaxanthin gavage-treated group (100 mg/kg, ATX) during recovery compared to the gavage-treated olive oil group (OIL), beginning at 24 h post-CHI and lasting throughout 28 days (p < 0.007). Astaxanthin pretreatment in pellet form produced a smaller improvement in NSS vs. posttreatment at 7 days post-CHI (p < 0.05). Cognitive and behavioral evaluation using the novel object recognition test (ORT) and the Y Maze test revealed an advantage for Astaxanthin administration via free eating vs. standard chow during recovery post-CHI (ORT at 3 days, p < 0.035; improvement in Y Maze score from 2 to 29 days, p < 0.02). HSP profile and anxiety (open field test) were not significantly affected by Astaxanthin. In conclusion, astaxanthin pretreatment may contribute to improved recovery post-TBI in mice and is influenced by the form of administration.

Engagement in Psychotherapy Improves Outcomes for Veterans

The longstanding partnership between the Birmingham Veterans Affairs Medical Center (BVAMC) and the University of Alabama at Birmingham School of Nursing inspired the establishment of one of the country's first psychiatric-mental health nurse practitioner (PMHNP) residencies and subsequent formation of a Resident Continuity Clinic (RCC). Within the RCC, PMHNP residents deliver evidence-based care that is informed by measurement-based care (MBC) to improve patient outcomes and reduce time to recovery. Determined by the BVAMC Institutional Review Board to be a quality improvement project, PMHNP residents administered the Patient Stress Questionnaire (PSQ), a MBC tool that uses four independently validated screening tools to measure the behavioral health symptoms of depression, anxiety, trauma, and alcohol use. Additional clinical variables of interest included patient use of illicit substances, participation in psychotherapy, and use of psychotropic medications. PSQ scores were reviewed retrospectively via descriptive statistics and nonparametric tests. Analysis demonstrated statistically significant improvements in depression and anxiety. Data also revealed that patients engaged in psychotherapy demonstrated greater improvements on all PSQ screening tools compared to patients not involved in psychotherapy. The results reinforce the value of MBC in psychiatric care and highlight the importance of engaging Veterans in psychotherapy to improve outcomes. [Journal of Psychosocial Nursing and Mental Health Services, 57(6), 30-38.].

Psychiatric Nurse Practitioner Residents Improve Quality and Mental Health Outcomes for Veterans Through Measurement-Based Care

INTRODUCTION

Measurement-based care (MBC) is commonly used to manage medical illness, whereas only about 20% of psychiatric care providers use MBC. One aim of the partnership between the Birmingham Veterans Affairs Medical Center (BVAMC) and the University of Alabama at Birmingham School of Nursing (UAB SON) is to provide MBC to Veterans. The goal is to describe the efficacy of MBC in the treatment of Veterans by psychiatric-mental health nurse practitioner (PMHNP) residents.

PURPOSE

By teaching PMHNP residents evidence-based assessment, they gain tools to shorten time to remission of depression, anxiety, and posttraumatic stress disorder.

METHODS

Residents administered the Patient Stress Questionnaire (PSQ), an MBC tool that assesses depression, anxiety, trauma-related symptoms, and alcohol use, to patients of the Residency Continuity Clinic (RCC). Patient Stress Questionnaire scores from March 2016 to May 2018 were analyzed using paired t tests.

RESULTS

Analysis revealed a downward trend in PSQ scores over time, suggesting improvement in psychiatric symptoms. Depressive and anxiety symptoms decreased significantly.

CONCLUSIONS/IMPLICATIONS

This quality project highlights the utility of MBC by PMHNP residents in an RCC. Measurement-based care tools can be quickly and easily administered with little impact on workflow. Use of validated screening tools can enhance care, engage patients, and improve patient outcomes.

Noncoding RNAs: Stress, Glucocorticoids, and Posttraumatic Stress Disorder

Posttraumatic stress disorder (PTSD) is a pathologic response to trauma that impacts ∼8% of the population and is highly comorbid with other disorders, such as traumatic brain injury. PTSD affects multiple biological systems throughout the body, including the hypothalamic-pituitary-adrenal axis, cortical function, and the immune system, and while the study of the biological underpinnings of PTSD and related disorders are numerous, the roles of noncoding RNAs (ncRNAs) are just emerging. Moreover, deep sequencing has revealed that ncRNAs represent most of the transcribed mammalian genome. Here, we present developing evidence that ncRNAs are involved in critical aspects of PTSD pathophysiology. In that regard, we summarize the roles of three classes of ncRNAs in PTSD and related disorders: microRNAs, long-noncoding RNAs, and retrotransposons. This review evaluates findings from both animal and human studies with a special focus on the role of ncRNAs in hypothalamic-pituitary-adrenal axis abnormalities and glucocorticoid dysfunction in PTSD and traumatic brain injury. We conclude that ncRNAs may prove to be useful biomarkers to facilitate personalized medicines for trauma-related brain disorders.

Traumatic exposures, posttraumatic stress disorder, and cognitive functioning in World Trade Center responders

INTRODUCTION

This study examined whether World Trade Center (WTC)-related exposures and posttraumatic stress disorder (PTSD) were associated with cognitive function and whether WTC responders' cognition differed from normative data.

METHODS

A computer-assisted neuropsychological battery was administered to a prospective cohort study of 1193 WTC responders with no history of stroke or WTC-related head injuries. Data were linked to information collected prospectively since 2002. Sample averages were compared to published norms.

RESULTS

Approximately 14.8% of sampled responders had cognitive dysfunction. WTC responders had worse cognitive function compared to normative data. PTSD symptom severity and working >5 weeks on-site was associated with lower cognition.

DISCUSSION

Results from this sample highlight the potential for WTC responders to be experiencing an increased burden of cognitive dysfunction and linked lowered cognitive functioning to physical exposures and to PTSD. Future research is warranted to understand the extent to which cognitive dysfunction is evident in neural dysfunction.

CNS findings in chronic fatigue syndrome and a neuropathological case report

Chronic fatigue syndrome (CFS) is characterized as a persistent, debilitating complex disorder of unknown etiology, whereby patients suffer from extreme fatigue, which often presents with symptoms that include chronic pain, depression, weakness, mood disturbances, and neuropsychological impairment. In this mini review and case report, we address central nervous system (CNS) involvement of CFS and present neuropathological autopsy findings from a patient who died with a prior diagnosis of CFS. Among the most remarkable pathological features of the case are focal areas of white matter loss, neurite beading, and neuritic pathology of axons in the white matter with axonal spheroids. Atypical neurons displaying aberrant sprouting processes in response to injury are observed throughout cortical gray and white matter. Abundant amyloid deposits identical to AD plaques with accompanying intracellular granular structures are observed as well. Neurofibrillary tangles are also present in the white matter of the frontal cortex, thalamus and basal ganglia. Taken together, these neuropathological findings warrant further studies into CNS disease associated with CFS.

Female Service Members and Symptom Reporting after Combat and Non-Combat-Related Mild Traumatic Brain Injury

Females are often excluded from military-related mild traumatic brain injury (mTBI) research because of its relatively low prevalence in this population. The purpose of this study was to focus on outcome from mTBI in female service members, compared with males. Participants were 172 United States military service members selected from a larger sample that had sustained an mTBI, and were evaluated within 24 months of injury (Age: mean = 28.9, SD = 8.1) at one of six military medical centers. Eighty-six women were matched to 86 men on nine key variables: TBI severity, mechanism of injury, bodily injury severity, days post-injury, age, number of deployments, theater where wounded, branch of service, and rank. Participants completed the Neurobehavioral Symptom Inventory (NSI) and the Posttraumatic Stress Disorder Checklist (PCL-C). There were no meaningful gender differences across all demographic and injury-related variables (p > 0.05). There were significant group differences and medium effect sizes for the NSI total score and all four NSI cluster scores. Symptoms most affected related to nausea, sensitivity to light, change in taste/smell, change in appetite, fatigue, and poor sleep. There were significant group differences and small-medium effect sizes for the PCL-C total score and two of the three PCL-C cluster scores. Symptoms most affected related to poor concentration, trouble remembering a stressful event, and disturbing memories/thoughts/images. Females consistently experienced more symptoms than males. As females become more active in combat-related deployments, it is critical that future studies place more emphasis on this important military population.

Occupational outcomes following mild traumatic brain injury in Canadian military personnel deployed in support of the mission in Afghanistan: a retrospective cohort study

OBJECTIVE

Deployment-related mild traumatic brain injury (MTBI) occurs in a significant number of military personnel but its long-term impacts are unclear. This study explores the impact of deployment-related MTBI on continued fitness-for-duty, with the ultimate intent of identifying potential targets for intervention to attenuate its effects.

PARTICIPANTS

Consisted of 16 193 Canadian Armed Forces (CAF) personnel who deployed in support of the mission in Afghanistan and completed an enhanced postdeployment screening (EPDS) questionnaire over the period January 2009-July 2012.

PRIMARY OUTCOME

The primary outcome was development of permanent medical unfitness defined as a 'career-limiting medical condition' (CL-MC). The secondary outcome was the diagnostic categories recorded for each individual at the time a CL-MC was established.

DESIGN

This study used a retrospective cohort design. Linked administrative and health data provided the primary outcome and the diagnoses responsible for it. Survival analysis was used to estimate the risk of a CL-MC and Cox regression provided adjusted HRs (aHRs) for the association between a CL-MC and MTBI, accounting for key covariates and confounders. Diagnostic categories associated with CL-MCs were identified.

RESULTS

Over a median follow-up period of 3.42 years, 6.57% of the study population developed a CL-MC. MTBI was independently associated with CL-MCs (aHR=1.65, 95% CI 1.35 to 2.03). Mental disorders and musculoskeletal conditions were the primary diagnoses associated with CL-MCs (identified as the primary diagnosis in 55.4% and 25.9%, respectively), and a neurological condition was only documented in 5.8% of those with MTBI who developed a CL-MC CONCLUSIONS: Deployment-related MTBI was associated with adverse occupational outcome but mental disorders and musculoskeletal conditions primarily drove subsequent medical unfitness. These findings support a diagnostic and treatment approach focusing on these comorbidities as the most promising strategy to minimise the burden of disability in MTBI-exposed military personnel.

Traumatic Brain Injury in United States Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) Hispanic Veterans-A Review Using the PRISMA Method

Traumatic brain injury (TBI) is commonly defined by Menon et al. as an "alteration of the brain function, or other evidence of brain pathology, caused by an external force." TBI can be caused by penetrating trauma to the head in which the magnitude of the injury is dependent on the magnitude of the forces that are applied to the head. The consequences of TBI can range from minimal to severe disability and even death. The major objectives of this systematic review are to survey the current literature on Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) Hispanic veterans with TBI. To complete this analysis, the Preferred Reporting Items for Systematic Reviews and MetaAnalysis (PRISMA) identified 875 articles in common and retrieved a total of 34 articles that met the inclusion criteria, consisted of OEF/OIF Hispanic veterans, reported quantitative data, and were conducted with adult U.S. veterans living in the United States. Since TBI diagnosis was unclear in most articles, only five articles that used the VATBIST instrument were analyzed. The results suggested that there is a lack of research on OEF/OIF Hispanic veterans and Hispanic subgroups. Future studies need to be conducted to consider minority groups while analyzing data involving TBI.

The Temporal Pattern of Changes in Serum Biomarker Levels Reveals Complex and Dynamically Changing Pathologies after Exposure to a Single Low-Intensity Blast in Mice

Time-dependent changes in blood-based protein biomarkers can help identify the ­pathological processes in blast-induced traumatic brain injury (bTBI), assess injury severity, and monitor disease progression. We obtained blood from control and injured mice (exposed to a single, low-intensity blast) at 2-h, 1-day, 1–week, and 1-month post-injury. We then determined the serum levels of biomarkers related to metabolism (4-HNE, HIF-1α, ceruloplasmin), vascular function (AQP1, AQP4, VEGF, vWF, Flk-1), inflammation (OPN, CINC1, fibrinogen, MIP-1a, OX-44, p38, MMP-8, MCP-1 CCR5, CRP, galectin-1), cell adhesion and the extracellular matrix (integrin α6, TIMP1, TIMP4, Ncad, connexin-43), and axonal (NF-H, Tau), neuronal (NSE, CK-BB) and glial damage (GFAP, S100β, MBP) at various post-injury time points. Our findings indicate that the exposure to a single, low-intensity blast results in metabolic and vascular changes, altered cell adhesion, and axonal and neuronal injury in the mouse model of bTBI. Interestingly, serum levels of several inflammatory and astroglial markers were either unchanged or elevated only during the acute and subacute phases of injury. Conversely, serum levels of the majority of biomarkers related to metabolic and vascular functions, cell adhesion, as well as neuronal and axonal damage remained elevated at the termination of the experiment (1 month), indicating long-term systemic and cerebral alterations due to blast. Our findings show that the exposure to a single, low-intensity blast induces complex pathological processes with distinct temporal profiles. Hence, monitoring serum biomarker levels at various post-injury time points may provide enhanced diagnostics in blast-related neurological and multi-system deficits.

Glial fibrillary acidic protein: from intermediate filament assembly and gliosis to neurobiomarker

Glial fibrillary acidic protein (GFAP) is an intermediate filament (IF) III protein uniquely found in astrocytes in the central nervous system (CNS), non-myelinating Schwann cells in the peripheral nervous system (PNS), and enteric glial cells. GFAP mRNA expression is regulated by several nuclear-receptor hormones, growth factors, and lipopolysaccharides (LPSs). GFAP is also subject to numerous post-translational modifications (PTMs), while GFAP mutations result in protein deposits known as Rosenthal fibers in Alexander disease. GFAP gene activation and protein induction appear to play a critical role in astroglial cell activation (astrogliosis) following CNS injuries and neurodegeneration. Emerging evidence also suggests that, following traumatic brain and spinal cord injuries and stroke, GFAP and its breakdown products are rapidly released into biofluids, making them strong candidate biomarkers for such neurological disorders.

Blast-related traumatic brain injury

A bomb blast may cause the full severity range of traumatic brain injury (TBI), from mild concussion to severe, penetrating injury. The pathophysiology of blast-related TBI is distinctive, with injury magnitude dependent on several factors, including blast energy and distance from the blast epicentre. The prevalence of blast-related mild TBI in modern war zones has varied widely, but detection is optimised by battlefield assessment of concussion and follow-up screening of all personnel with potential concussive events. There is substantial overlap between post-concussive syndrome and post-traumatic stress disorder, and blast-related mild TBI seems to increase the risk of post-traumatic stress disorder. Post-concussive syndrome, post-traumatic stress disorder, and chronic pain are a clinical triad in this patient group. Persistent impairment after blast-related mild TBI might be largely attributable to psychological factors, although a causative link between repeated mild TBIs caused by blasts and chronic traumatic encephalopathy has not been established. The application of advanced neuroimaging and the identification of specific molecular biomarkers in serum for diagnosis and prognosis are rapidly advancing, and might help to further categorise these injuries.

Managing behavioral health needs of veterans with traumatic brain injury (TBI) in primary care

Traumatic brain injury (TBI) is a frequent occurrence in the United States, and has been given particular attention in the veteran population. Recent accounts have estimated TBI incidence rates as high as 20 % among US veterans who served in Afghanistan or Iraq, and many of these veterans experience a host of co-morbid concerns, including psychiatric complaints (such as depression and post-traumatic stress disorder), sleep disturbance, and substance abuse which may warrant referral to behavioral health specialists working in primary care settings. This paper reviews many common behavioral health concerns co-morbid with TBI, and suggests areas in which behavioral health specialists may assess, intervene, and help to facilitate holistic patient care beyond the acute phase of injury. The primary focus is on sequelae common to mild and moderate TBI which may more readily present in primary care clinics.

Serum-based protein biomarkers in blast-induced traumatic brain injury spectrum disorder

The biological consequences of exposure to explosive blast are extremely complex. Serum protein biomarkers in blast-induced traumatic brain injury (bTBI) can aid in determining injury severity, monitoring progress, and predicting outcome. Exposure to blast results in varying degrees of physical injury. Explosive blast can also induce psychological stress that can contribute to or amplify the extent of physical damage. Given the complexity, scale of injury, and variety of symptoms, bTBI may be best described as a spectrum disorder. In this focused review, we summarize the status of serum protein biomarkers in bTBI in the context of the classification and pathological changes of other forms of TBI. Finally, we recommend specific and easily implementable measures to accelerate serum protein biomarker discovery and validation in bTBI.

Neuropsychological outcome from blast versus non-blast: mild traumatic brain injury in U.S. military service members

The purpose of this study was to compare the neuropsychological outcome from blast-related versus non-blast related mild traumatic brain injury (MTBI). Participants were 56 U.S. military service members who sustained an MTBI, divided into two groups based on mechanism of injury: (a) non-blast related (Non-blast; n = 21), and (b) blast plus secondary blunt trauma (Blast Plus; n = 35). All participants had sustained their injury in theatre whilst deployed during Operation Iraqi Freedom or Operation Enduring Freedom. Patients had been seen for neuropsychological evaluation at Walter Reed Army Medical Center on average 4.4 months (SD = 4.1) post-injury. Measures included 14 clinical scales from the Personality Assessment Inventory (PAI) and 12 common neurocognitive measures. For the PAI, there were no significant differences between groups on all scales (p > .05). However, medium effect sizes were found for the Depression (d = .49) and Stress (d = .47) scales (i.e., Blast Plus > Non-blast). On the neurocognitive measures, after controlling for the influence of psychological distress (i.e., Depression, Stress), there were no differences between the Non-blast and Blast Plus groups on all measures. These findings provide little evidence to suggest that blast exposure plus secondary blunt trauma results in worse cognitive or psychological recovery than blunt trauma alone. (JINS, 2012, 18, 595-605).

Deployment-related TBI, persistent postconcussive symptoms, PTSD, and depression in OEF/OIF veterans

OBJECTIVE

A substantial proportion of the more than 2 million service members who have served in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) have experienced a traumatic brain injury (TBI). Understanding the long-term impact of TBI is complicated by the nonspecific nature of postconcussive symptoms (PCSs) and the high rates of co-occurrence among TBI, posttraumatic stress disorder (PTSD), and depression. The goal of the present research was to examine the relations among TBI, persistent PCSs, and symptoms of PTSD and depression among returning OEF/OIF veterans.

METHOD

213 OEF/OIF veterans (87% male) completed a semistructured screening interview assessing deployment-related TBI and current, persistent PCSs. Participants also completed self-report measures of combat exposure and current symptoms of PTSD and depression.

RESULTS

Nearly half (46%) of sampled veterans screened positive for TBI, the majority of whom (85%) reported at least one persistent PCS after removing PCSs that overlapped with PTSD and depression. Veterans with deployment-related TBI reported higher levels of combat exposure and symptoms of PTSD and depression. Structural equation modeling was used to assess the fit of 3 models of the relationships among TBI, combat exposure, persistent PCSs, PTSD, and depression. Consistent with hypotheses, the best-fitting model was one in which the effects of TBI on both PTSD and depression were fully mediated by nonoverlapping persistent PCSs.

CONCLUSIONS

These findings highlight the importance of addressing persistent PCSs in order to facilitate the functional recovery of returning war veterans.

Noise-Induced Hearing Injury and Comorbidities Among Postdeployment U.S. Army Soldiers: April 2003–June 2009

Purpose

To evaluate noise-induced hearing injury (NIHI) and blast-related comorbidities among U.S. Army soldiers in an effort to understand the morbidity burden and future health service requirements for wounded war fighters returning from the Central Command Area of Responsibility, predominantly from Iraq and Afghanistan deployments.

Method

Inpatient and outpatient records with diagnosed NIHI or blast-related comorbidities (e.g., significant threshold shift [STS], noise-induced hearing loss, tinnitus, sensorineural hearing loss, eardrum perforations, mild traumatic brain injury, and posttraumatic stress disorder) were extracted for active duty soldiers returning from combat deployments. Records were limited to those within 6 months of the soldier’s return date from April 2003 through June 2009. To account for changes in STS coding practice, STS rates observed after October 1, 2006, were used to extrapolate prior probable postdeployment STS.

Results

Statistically significant increases were observed for tinnitus, dizziness, eardrum perforations, and speech-language disorders. The combination of observed and extrapolated STS yielded a conservative estimate of 27,427 cases.

Conclusions

Estimates can be used to forecast resource requirements for hearing services among veterans. This article could serve as a guide for resourcing and innovating prevention measures and treatment in this population. Data provided may also serve as a baseline for evaluating prevention measures.

Stress and traumatic brain injury: a behavioral, proteomics, and histological study

Psychological stress and traumatic brain injury (TBI) can both result in lasting neurobehavioral abnormalities. Post-traumatic stress disorder and blast induced TBI (bTBI) have become the most significant health issues in current military conflicts. Importantly, military bTBI virtually never occurs without stress. In this experiment, we assessed anxiety and spatial memory of rats at different time points after repeated exposure to stress alone or in combination with a single mild blast. At 2 months after injury or sham we analyzed the serum, prefrontal cortex (PFC), and hippocampus (HC) of all animals by proteomics and immunohistochemistry. Stressed sham animals showed an early increase in anxiety but no memory impairment at any measured time point. They had elevated levels of serum corticosterone (CORT) and hippocampal IL-6 but no other cellular or protein changes. Stressed injured animals had increased anxiety that returned to normal at 2 months and significant spatial memory impairment that lasted up to 2 months. They had elevated serum levels of CORT, CK-BB, NF-H, NSE, GFAP, and VEGF. Moreover, all of the measured protein markers were elevated in the HC and the PFC; rats had an increased number of TUNEL-positive cells in the HC and elevated GFAP and Iba1 immunoreactivity in the HC and the PFC. Our findings suggest that exposure to repeated stress alone causes a transient increase in anxiety and no significant memory impairment or cellular and molecular changes. In contrast, repeated stress and blast results in lasting behavioral, molecular, and cellular abnormalities characterized by memory impairment, neuronal and glial cell loss, inflammation, and gliosis. These findings may have implications in the development of diagnostic and therapeutic measures for conditions caused by stress or a combination of stress and bTBI.

Blast-induced mild traumatic brain injury

Traumatic brain injury (TBI) has been a major cause of mortality and morbidity in the wars in Iraq and Afghanistan. Blast exposure has been the most common cause of TBI, occurring through multiple mechanisms. What is less clear is whether the primary blast wave causes brain damage through mechanisms that are distinct from those common in civilian TBI and whether multiple exposures to low-level blast can lead to long-term sequelae. Complicating TBI in soldiers is the high prevalence of posttraumatic stress disorder. At present, the relationship is unclear. Resolution of these issues will affect both treatment strategies and strategies for the protection of troops in the field.

Synergistic benefits of erythropoietin and simvastatin after traumatic brain injury

Simvastatin and recombinant human erythropoietin (rhEpo) are implicated as potential therapeutic candidates for traumatic brain injury (TBI). Prominent effects of simvastatin include its anti-inflammatory, neurotrophic and neuroregenerative actions studied in various models of neuronal injury. On the other hand, rhEpo has been shown to promote cell survival mechanisms by producing anti-apoptotic and cell proliferative actions. Beneficial effects of rhEpo and statin monotherapies have been well studied. However, there are no reports showing combined use of rhEpo and statins after TBI. This investigation examined if combined efficacy of cell proliferative ability of rhEpo along with the neuroregenerative ability of simvastatin will render maximum recovery in a controlled cortical impact (CCI) mouse model of TBI. Results showed that compared to baseline TBI, rhEpo was more effective than simvastatin in promoting cell proliferation while simvastatin was more effective than rhEpo in restoring axonal damage following TBI. Combined treatment with simvastatin and rhEpo maximally restored axonal integrity while simultaneously inducing greater proliferation of newly formed cells resulting in better functional recovery after TBI than either alone. This is the first study showing the efficacy of erythropoietin-simvastatin combinational therapeutic approach in achieving greater structural and cognitive recovery after TBI.

Mechanisms of blast induced brain injuries, experimental studies in rats

Traumatic brain injuries (TBI) potentially induced by blast waves from detonations result in significant diagnostic problems. It may be assumed that several mechanisms contribute to the injury. This study is an attempt to characterize the presumed components of the blast induced TBI. Our experimental models include a blast tube in which an anesthetized rat can be exposed to controlled detonations of explosives that result in a pressure wave with a magnitude between 130 and 260 kPa. In this model, the animal is fixed with a metal net to avoid head acceleration forces. The second model is a controlled penetration of a 2mm thick needle. In the third model the animal is subjected to a high-speed sagittal rotation angular acceleration. Immunohistochemical labeling for amyloid precursor protein revealed signs of diffuse axonal injury (DAI) in the penetration and rotation models. Signs of punctuate inflammation were observed after focal and rotation injury. Exposure in the blast tube did not induce DAI or detectable cell death, but functional changes. Affymetrix Gene arrays showed changes in the expression in a large number of gene families including cell death, inflammation and neurotransmitters in the hippocampus after both acceleration and penetration injuries. Exposure to the primary blast wave induced limited shifts in gene expression in the hippocampus. The most interesting findings were a downregulation of genes involved in neurogenesis and synaptic transmission. These experiments indicate that rotational acceleration may be a critical factor for DAI and other acute changes after blast TBI. The further exploration of the mechanisms of blast TBI will have to include a search for long-term effects.