Amnesia, traumatic brain injury, and posttraumatic stress disorder: a methodological inquiry

Clinical Trajectories of Comorbidity Associated With Military-Sustained Mild Traumatic Brain Injury: Pre- and Post-Injury

BACKGROUND AND OBJECTIVE

In the US military, traumatic brain injury (TBI) is of distinct importance, at home and in the deployed setting, and is considered a "signature injury of the wars in Afghanistan and Iraq." Since 2000, an estimated 468 424 service members (SMs) have been diagnosed with at least one TBI. We examined the clinical trajectories of a group of 18 comorbidities before and after a military-sustained mild TBI (mTBI).

METHODS

Without making assumptions on causality, a group of 18 conditions often co-occurring with mTBI were identified through literature review and TBI subject matter workgroup consensus. Using data from Military Health System Data Repository, we identified SMs whose first lifetime military mTBI occurred between October 1, 2016, and October 30, 2019. Correlation analyses were used to determine the linear relationship between comorbidities prior to and after mTBI diagnosis. Changes in the period prevalence of comorbidities was calculated.

RESULTS

We identified 42 018 SMs with a first lifetime military mTBI, of which 77.6% had at least one comorbidity. Identified SMs were mostly young (46.1% ages 18-24 years), male (81.4%), and White (64.1%). Up to 180 days prior to an mTBI, the most frequently identified conditions were sleep-related conditions (21.7%), headaches (19.4%), posttraumatic stress disorders (PTSDs) (17.8%), anxiety disorders (11.3%), and cervicogenic disorders (eg, cervicalgia) (10.9%). In the period following mTBI diagnosis, the prevalence of diagnosed conditions increased, especially for visual disturbances (327.2%), cognitive conditions (313.9%), vestibular conditions (192.6%), those related to headache (152.2%), and hearing (72.9%). Sleep-related conditions showed moderate positive correlation with a group of co-occurring conditions, led by cognitive conditions (ϕc = 0.50), anxiety disorders (ϕc = 0.42), PTSDs (ϕc =0.43), and headaches and related conditions (ϕc = 0.38).

CONCLUSION

Results indicate that caring for SMs with mild TBI requires a holistic approach, one that considers the complex nature of SM conditions, prior to sustaining their mTBI, as well as after injury. We found a complex correlation of conditions that suggest SMs with mTBI are undergoing a multifaceted experience, one that may require the development of a targeted multidimensional clinical practice recommendation and practice.

Treatment Patterns of Anxiety and Posttraumatic Stress Disorder Following Traumatic Brain Injury

OBJECTIVE

Symptoms of mental disorders are common, are underrecognized, and contribute to worse outcomes after traumatic brain injury (TBI). Post-TBI, prevalence of anxiety disorders and prevalence of posttraumatic stress disorder (PTSD) are comparable with that of depression, but evidence-based treatment guidelines are lacking. The investigators examined psychotropic medication use and psychotherapy patterns among individuals diagnosed with anxiety disorders and PTSD post-TBI.

METHODS

Administrative claims data were used to compare the prevalence and patterns of pharmacotherapy and psychotherapy utilization among individuals diagnosed with an anxiety disorder or PTSD post-TBI.

RESULTS

Among 207,354 adults with TBI, prevalence of anxiety disorders was 20.5%, and prevalence of PTSD was 0.6% post-TBI. Receipt of pharmacotherapy pre- and post-TBI (anxiety: pre-TBI=58.4%, post-TBI=76.2%; PTSD: pre-TBI=53.7%, post-TBI=75.2%) was considerably more common than receipt of psychotherapy (anxiety: pre-TBI=5.8%, post-TBI=19.1%; PTSD: pre-TBI=11.2%, post-TBI=36.0%). Individuals diagnosed with anxiety were 66% less likely to receive psychotherapy compared with individuals diagnosed with PTSD, although engagement in psychotherapy decreased faster over time among those with PTSD. Overall, psychotropic medication use and rates of antidepressant prescription use in the anxiety group were higher compared with those in the PTSD group. Benzodiazepines were the second most commonly prescribed medication class in the anxiety group, even though judicious use is warranted post-TBI.

CONCLUSIONS

Further exploration of differences and risks associated with pharmacotherapy for anxiety and PTSD post-TBI is warranted to refine treatment guidelines. The low level of psychotherapy engagement suggests that barriers and facilitators to psychotherapy utilization post-TBI should be examined in future studies.

Screening tools for predicting posttraumatic stress disorder in acutely injured adult trauma patients: A systematic review

BACKGROUND

Adult trauma patients are at risk of developing posttraumatic stress disorder (PTSD). Early intervention reduces the development of PTSD, but few trauma patients seek and obtain care. Valid and reliable screening tools are needed to identify patients at risk of developing PTSD. The objective of this review is to identify existing screening tools and evaluate their accuracy for predicting PTSD outcomes.

METHODS

PubMed, PsychInfo, and ClinicalTrials.gov were searched for studies evaluating the predictive accuracy of PTSD screening tools among traumatically injured adult civilians. Eligible studies assessed patients during acute hospitalization and at least 1 month following injury to measure PTSD outcome. Eligible outcomes included measures of predictive accuracy, such as sensitivity and specificity. The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess the risk of bias of each study, and the strength of evidence was assessed following the Agency for Healthcare Research and Quality guidelines.

RESULTS

Forty-nine studies were included evaluating the predictive accuracy of 38 screening tools. Most tools were assessed in a single study. Questionnaire-style tools had more favorable predictive ability than diagnostic interview assessments. The Injured Trauma Survivor Screen, Posttraumatic Adjustment Screen, the PTSD Checklist for DSM-5, and the Richmond et al. tool demonstrated the most favorable predictive accuracy, with high sensitivity (75-100%) and specificity (67-94%). Common sources of bias were selection bias due to high attrition rate and using nondiagnostic tools to assess PTSD symptoms at follow-up.

CONCLUSION

Although sensitivity and specificity of PTSD predictive tools varied widely, several emerged with favorable predictive accuracy. Further research is needed to define the ability of screening and intervention to prevent PTSD in injured trauma survivors. The results of this review can inform screening tool options for screening programs and future intervention studies.

LEVEL OF EVIDENCE

Systematic review, level III.

The role of the stress system in recovery after traumatic brain injury: A tribute to Bruce S. McEwen

Traumatic brain injury (TBI) represents a major public health concern. Although the majority of individuals that suffer mild-moderate TBI recover relatively quickly, a substantial subset of individuals experiences prolonged and debilitating symptoms. An exacerbated response to physiological and psychological stressors after TBI may mediate poor functional recovery. Individuals with TBI can suffer from poor stress tolerance, impairments in the ability to evaluate stressors, and poor initiation (and cessation) of neuroendocrine stress responses, all of which can exacerbate TBI-mediated dysfunction. Here, we pay tribute to the pioneering neuroendocrinologist Dr. Bruce McEwen by discussing the ways in which his work on stress physiology and allostatic loading impacts the TBI patient population both before and after their injuries. Specifically, we will discuss the modulatory role of hypothalamic-pituitary-adrenal axis responses immediately after TBI and later in recovery. We will also consider the impact of stressors and stress responses in promoting post-concussive syndrome and post-traumatic stress disorders, two common sequelae of TBI. Finally, we will explore the role of early life stressors, prior to brain injuries, as modulators of injury outcomes.

Preliminary validation of the Dutch version of the Posttraumatic stress disorder checklist for DSM-5 (PCL-5) after traumatic brain injury in a civilian population

The Posttraumatic stress disorder checklist (PCL) is the most widely used questionnaire to screen for symptoms of posttraumatic stress disorder (PTSD), based on the Diagnostic and Statistical manual of Mental disorders (DSM-IV) criteria. In the latest edition of the DSM (DSM-5), the criteria for PTSD were revised leading to the development of the PCL-5. So far, there is no validated Dutch version of the PCL-5. The aim of this study is to determine psychometric characteristics of the Dutch translation and linguistic validation of the PCL-5 and to evaluate internal consistency, criterion and structural validity. In a population of 495 civilian, traumatic brain injury patients, the PCL-5, the Generalized anxiety disorder questionnaire and the Depression scale of the Patient health questionnaire were administered. The PCL-5 was translated in Dutch following a strict procedure of linguistic validation and cognitive debriefing. Results show an excellent internal consistency and high criterion validity. Confirmatory factor analysis demonstrated a good fit for the four-factor DSM-5 model, but a superior fit for the six-factor Anhedonia model and the seven-factor Hybrid model, similar to the English version of the PCL-5. Preliminary validation of the Dutch translation of the PCL-5 was proven to be psychometrically sound and can be used for clinical and academic purposes, specifically for TBI patients. Future research should examine concurrent and discriminant validity for the Dutch translation in broader populations at risk for PTSD, and include a structured interview to evaluate diagnostic utility.

Post-Traumatic Stress Disorder after Civilian Traumatic Brain Injury: A Systematic Review and Meta-Analysis of Prevalence Rates

Post-traumatic stress disorder (PTSD) is a commonly diagnosed psychiatric disorder following traumatic brain injury (TBI). Much research on PTSD and TBI has focused on military conflict settings. Less is known about PTSD in civilian TBI. We conducted a systematic review and meta-analysis on the prevalence of PTSD after mild and moderate/severe TBI in civilian populations. We further aimed to explore the influence of methodological quality and assessment methods.

A systematic literature search was performed on studies reporting on PTSD in civilian TBI, excluding studies on military populations. The risk of bias was assessed using the MORE (Methodological evaluation of Observational REsearch) checklist. Meta-analysis was conducted for overall prevalence rates for PTSD with sensitivity analyses for the severity of TBI.

Fifty-two studies were included, of which 31 were graded as low risk of bias. Prevalence rates of PTSD in low risk of bias studies varied widely (2.6–36%) with a pooled prevalence rate of 15.6%. Pooled prevalence rates of PTSD for mild TBI (13.5%, 95% confidence interval [CI]: 11.7–15.3; I² = 2%) did not differ from moderate/severe TBI (11.8, 95% CI: 7.5–16.1; I² = 63%). Similar rates were reported in studies using different approaches and times of assessment. Although most studies that compared participants with TBI with trauma patients and healthy controls found no difference in prevalence rates of PTSD, a meta-analysis across studies revealed a higher prevalence of PTSD in patients with TBI (odds ratio [OR]: 1.73, 95% CI: 1.21–2.47).

This review highlights variability between studies and emphasizes the need for higher-quality studies. Further research is warranted to determine risk factors for the development of PTSD after TBI.

Sleep, Sleep Disorders, and Circadian Health following Mild Traumatic Brain Injury in Adults: Review and Research Agenda

A rapidly expanding scientific literature supports the frequent co-occurrence of sleep and circadian disturbances following mild traumatic brain injury (mTBI). Although many questions remain unanswered, the preponderance of evidence suggests that sleep and circadian disorders can result from mTBI. Among those with mTBI, sleep disturbances and clinical sleep and circadian disorders contribute to the morbidity and long-term sequelae across domains of functional outcomes and quality of life. Specifically, along with deterioration of neurocognitive performance, insufficient and disturbed sleep can precede, exacerbate, or perpetuate many of the other common sequelae of mTBI, including depression, post-traumatic stress disorder, and chronic pain. Further, sleep and mTBI share neurophysiologic and neuroanatomic mechanisms that likely bear directly on success of rehabilitation following mTBI. For these reasons, focus on disturbed sleep as a modifiable treatment target has high likelihood of improving outcomes in mTBI. Here, we review relevant literature and present a research agenda to 1) advance understanding of the reciprocal relationships between sleep and circadian factors and mTBI sequelae and 2) advance rapidly the development of sleep-related treatments in this population.

Recovery from trauma induced amnesia correlates with normalization of thrombin activity in the mouse hippocampus

Transient amnesia is a common consequence of minimal traumatic brain injury (mTBI). However, while recent findings have addressed the mechanisms involved in its onset, the processes contributing to its recovery have not yet been addressed. Recently, we have found that thrombin is detected at high concentrations in the brain of mice after exposure to mTBI and that in such settings amnesia is rescued by either inhibiting thrombin activity or by blockade of PAR1. Here, we report that mice spontaneously recover from amnesia after two weeks from mTBI exposure. At this time point, long term potentiation was equally evoked in injured vs. control animals with thrombin concentration in the brain being normalized at this stage. These findings, which refer to the specific aspect of memory retrieval upon mTBI, together with our previous work, hint to a strong correlation between cognitive defects in the context of mTBI and thrombin concentrations in the brain. This may suggest that a possible scavenging of thrombin in the brain at early phases following mTBI may improve memory function.

Prevalence of and Risk Factors for Anxiety and Depressive Disorders after Traumatic Brain Injury: A Systematic Review

This review examined pre- and post-injury prevalence of, and risk factors for, anxiety disorders and depressive disorders after traumatic brain injury (TBI), based on evidence from structured diagnostic interviews. A systematic literature search was conducted in EMBASE, MEDLINE, Cochrane Central, PubMed, PsycINFO, and Google Scholar. We identified studies in civilian adults with TBI reporting on the prevalence of anxiety and depressive disorders using structured diagnostic interviews and assessed their quality. Pooled pre- and post-injury prevalence estimates of anxiety disorders and depressive disorders were computed. A total of 34 studies described in 68 publications were identified, often assessing anxiety disorders (n = 9), depressive disorders (n = 7), or a combination of disorders (n = 6). Prevalence rates of psychiatric disorders varied widely. Pooled prevalence estimates of anxiety and depressive disorders were 19% and 13% before TBI and 21% and 17% in the first year after TBI. Pooled prevalence estimates increased over time and indicated high long-term prevalence of Axis I disorders (54%), including anxiety disorders (36%) or depressive disorders (43%). Females, those without employment, and those with a psychiatric history before TBI were at higher risk for anxiety and depressive disorders after TBI. We conclude that a substantial number of patients encounter anxiety and depressive disorders after TBI, and that these problems persist over time. All health care settings should pay attention to the occurrence of psychiatric symptoms in the aftermath of TBI to enable early identification and treatment of these disorders and to enhance the recovery and quality of life of TBI survivors.

Role of Systems Biology in Brain Injury Biomarker Discovery: Neuroproteomics Application

Years of research in the field of neurotrauma have led to the concept of applying systems biology as a tool for biomarker discovery in traumatic brain injury (TBI). Biomarkers may lead to understanding mechanisms of injury and recovery in TBI and can be potential targets for wound healing, recovery, and increased survival with enhanced quality of life. The literature available on neurotrauma studies from both animal and clinical studies has provided rich insight on the molecular pathways and complex networks of TBI, elucidating the proteomics of this disease for the discovery of biomarkers. With such a plethora of information available, the data from the studies require databases with tools to analyze and infer new patterns and associations. The role of different systems biology tools and their use in biomarker discovery in TBI are discussed in this chapter.

Alterations in autobiographical memory for a blast event in Operation Enduring Freedom and Operation Iraqi Freedom veterans with mild traumatic brain injury

OBJECTIVE

Although loss of consciousness associated with moderate or severe traumatic brain injury (TBI) is thought to interfere with encoding of the TBI event, little is known about the effects of mild TBI (mTBI), which typically involves only transient disruption in consciousness.

METHOD

Blast-exposed Afghanistan and Iraq War veterans were asked to recall the blast event. Participants were stratified based on whether the blast was associated with probable mTBI (n = 50) or not (n = 25). Narratives were scored for organizational structure (i.e., coherence) using the Narrative Coherence Coding Scheme (Reese et al., 2011) and episodic recollection using the Autobiographical Interview Coding Procedures (Levine et al., 2002).

RESULTS

The mTBI group produced narratives that were less coherent but contained more episodic details than those of the no-TBI group.

CONCLUSION

These results suggest that mTBI interferes with the organizational quality of memory in a manner that is independent of episodic detail generation.

The manifestation of anxiety disorders after traumatic brain injury: a review

The development of anxiety disorders after a traumatic brain injury (TBI) is a strong predictor of social, personal, and work dysfunction; nevertheless, the emergence of anxiety has been largely unexplored and poorly understood in the context of TBI. This article provides an overview of the limited published research to date on anxiety disorders that are known to develop after TBI, including post-traumatic stress disorder, generalized anxiety disorder, obsessive-compulsive disorder, panic disorder, specific phobia, and social anxiety disorder. This review also examines diagnostic criteria, the epidemiology of each disorder, and the factors that influence the expression of these conditions, including injury-related and psychosocial variables. Putative neural correlates will be reviewed where known. A discussion of current treatment options and avenues for further research are explored.

Combat-related blast exposure and traumatic brain injury influence brain glucose metabolism during REM sleep in military veterans

Traumatic brain injury (TBI), a signature wound of Operations Enduring and Iraqi Freedom, can result from blunt head trauma or exposure to a blast/explosion. While TBI affects sleep, the neurobiological underpinnings between TBI and sleep are largely unknown. To examine the neurobiological underpinnings of this relationship in military veterans, [(18)F]-fluorodeoxyglucose positron emission tomography (FDG PET) was used to compare mTBI-related changes in relative cerebral metabolic rate of glucose (rCMRglc) during wakefulness, Rapid Eye Movement (REM) sleep, and non-REM (NREM) sleep, after adjusting for the effects of posttraumatic stress (PTS). Fourteen veterans with a history of blast exposure and/or mTBI (B/mTBI) (age 27.5±3.9) and eleven veterans with no history (No B/mTBI) (age 28.1±4.3) completed FDG PET studies during wakefulness, REM sleep, and NREM sleep. Whole-brain analyses were conducted using Statistical Parametric Mapping (SPM8). Between group comparisons revealed that B/mTBI was associated with significantly lower rCMRglc during wakefulness and REM sleep in the amygdala, hippocampus, parahippocampal gyrus, thalamus, insula, uncus, culmen, visual association cortices, and midline medial frontal cortices. These results suggest that alterations in neurobiological networks during wakefulness and REM sleep subsequent to B/mTBI exposure may contribute to chronic sleep disturbances and differ in individuals with acute symptoms.

Deployment-related mental health support: comparative analysis of NATO and allied ISAF partners

BACKGROUND

For years there has been a tremendous gap in our understanding of the mental health effects of deployment and the efforts by military forces at trying to minimize or mitigate these. Many military forces have recently systematized the mental support that is provided to support operational deployments. However, the rationale for doing so and the consequential allocation of resources are felt to vary considerably across North Atlantic Treaty Organisation (NATO) International Security Assistance (ISAF) partners. This review aims to compare the organization and practice of mental support by five partnering countries in the recent deployment in Afghanistan in order to identify and compare the key methods and structures for delivering mental health support, describe bottlenecks and illustrate new developments.

METHOD

Information was collected through document analysis and semi-structured interviews with key military mental healthcare stakeholders. The review resulted from close collaboration between key military mental healthcare professionals within the Australian Defense Forces (ADF), Canadian Armed Forces (CAF), United Kingdom Armed Forces (UK), Netherlands Armed Forces (NLD), and the United States Army (US). Key stakeholders were interviewed about the mental health support provided during a serviceperson's military career. The main items discussed were training, prevention, early identification, intervention, and aftercare in the field of mental health.

RESULTS

All forces reported that much attention was paid to mental health during the individual's military career, including deployment. In doing so there was much overlap between the rationale and applied methods. The main method of providing support was through training and education. The educative focus was to strengthen the mental resilience of individual soldiers while providing a range of mental healthcare services. All forces had abandoned standard psychological debriefing after critical incidents. Instead, by default, mental healthcare professionals acted to support the leader and peer led "after action" reviews. All countries provided professional mental support close to the front line, aimed at early detection and early return to normal activities within the unit. All countries deployed a mental health support team that consisted of a range of mental health staff including psychiatrists, psychologists, social workers, mental health nurses, and chaplains. There was no overall consensus in the allocation of mental health disciplines in theatre. All countries (except the US) provided troops with a third location decompression (TLD) stop after deployment, which aimed to recognize what the deployed units had been through and to prepare them for transition home. The US conducted in-garrison 'decompression', or 'reintegration training' in the US, with a similiar focus to TLD. All had a reasonably comparable infrastructure in the field of mental healthcare. Shared bottlenecks across countries included perceived stigma and barriers to care around mental health problems as well as the need for improving the awareness and recognition of mental health problems among service members.

CONCLUSION

This analysis demonstrated that in all five partners state-of-the-art preventative mental healthcare was included in the last deployment in Afghanistan, including a positive approach towards strengthening the mental resilience, a focus on self-regulatory skills and self-empowerment, and several initiatives that were well-integrated in a military context. These initiatives were partly/completely implemented by the military/colleagues/supervisors and applicable during several phases of the deployment cycle. Important new developments in operational mental health support are recognition of the role of social leadership and enhancement of operational peer support. This requires awareness of mental problems that will contribute to reduction of the barriers to care in case of problems. Finally, comparing mental health support services across countries can contribute to optimal preparation for the challenges of military deployment.

Traumatic brain injury and posttraumatic stress disorder

Given the upsurge of research in posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI), much of which has focused on military samples who served in Iraq and Afghanistan, the purpose of this article is to review the literature published after September 11th, 2001 that addresses the epidemiology, pathophysiology, evaluation, and treatment of PTSD in the context of TBI.

Head injury and loss of consciousness raise the likelihood of developing and maintaining PTSD symptoms

Mild traumatic brain injury has been associated with higher prevalence of posttraumatic stress disorder (PTSD). The extent to which head injury or loss of consciousness predicts PTSD is unknown. To evaluate the contribution of head injury and loss of consciousness to the occurrence of PTSD, we made a longitudinal evaluation of 1,260 road accident survivors admitted to the emergency department with head injury (n = 287), head injury and loss of consciousness (n = 115), or neither (n = 858). A telephone-administered posttraumatic symptoms scale inferred PTSD and quantified PTSD symptoms at 10 days and 8 months after admission. The study groups had similar heart rate, blood pressure, and pain levels in the emergency department. Survivors with loss of consciousness and head injury had higher prevalence of PTSD and higher levels of PTSD symptoms, suggesting that patients with head injury and loss of consciousness reported in the emergency department are at higher risk for PTSD.

Biomarkers for the diagnosis and prognosis of mild traumatic brain injury/concussion

Mild traumatic brain injury (mTBI) results from a transfer of mechanical energy into the brain from traumatic events such as rapid acceleration/deceleration, a direct impact to the head, or an explosive blast. Transfer of energy into the brain can cause structural, physiological, and/or functional changes in the brain that may yield neurological, cognitive, and behavioral symptoms that can be long-lasting. Because mTBI can cause these symptoms in the absence of positive neuroimaging findings, its diagnosis can be subjective and often is based on self-reported neurological symptoms. Further, proper diagnosis can be influenced by the motivation to conceal or embellish signs and/or an inability of the patient to notice subtle dysfunctions or alterations of consciousness. Therefore, appropriate diagnosis of mTBI would benefit from objective indicators of injury. Concussion and mTBI are often used interchangeably, with concussion being primarily used in sport medicine, whereas mTBI is used in reference to traumatic injury. This review provides a critical assessment of the status of current biomarkers for the diagnosis of human mTBI. We review the status of biomarkers that have been tested in TBI patients with injuries classified as mild, and introduce a new concept for the discovery of biomarkers (termed symptophenotypes) to predict common and unique symptoms of concussion. Finally, we discuss the need for biomarker/biomarker signatures that can detect mTBI in the context of polytrauma, and to assess the consequences of repeated injury on the development of secondary injury syndrome, prolongation of post-concussion symptoms, and chronic traumatic encephalopathy.

Preinjury resilience and mood as predictors of early outcome following mild traumatic brain injury

There is significant heterogeneity in outcomes following mild traumatic brain injury (mTBI). While several host factors (age, gender, and preinjury psychiatric history) have been investigated, the influence of preinjury psychological resilience and mood status in conjunction with mild TBI remains relatively unexplored. Euthymic mood and high resilience are potentially protective against anxiety and postconcussion symptoms, but their relative contributions are currently unknown. This prospective study obtained preinjury estimates of resilience and mood measures in addition to measures of anxiety (Acute Stress Disorder Scale and PTSD-Checklist-Civilian form) and postconcussion symptom severity (Rivermead Post Concussion Symptoms Questionnaire) <24 hours (Baseline), 1 week, and 1 month postinjury in patients with either mTBI (n=46) or a comparison group with orthopedic injuries not involving the head (OI, n=29). The groups did not differ on preinjury resilience or mood status at baseline, but differed significantly on measures of anxiety and postconcussion symptom severity at each subsequent study occasion. Multivariate linear regression analyses were conducted to determine if preinjury resilience and mood were significant contributors to anxiety and postconcussion symptoms during the first month postinjury after accounting for other known host factors (e.g., age at injury, gender, and education). Injury group and preinjury mood status were significant predictors for all three dependent variables at each study occasion (all p<0.007). Preinjury resilience showed a positive trend only for acute stress severity at baseline, but demonstrated significant prediction of all three dependent measures at one week and one month postinjury. These results suggest that preinjury depressed mood and resilience are significant contributors to the severity of postinjury anxiety and postconcussion symptoms, even after accounting for effects of other specific host factors.

Analysis of functional pathways altered after mild traumatic brain injury

Concussive injury (or mild traumatic brain injury; mTBI) can exhibit features of focal or diffuse injury patterns. We compared and contrasted the cellular and molecular responses after mild controlled cortical impact (mCCI; a focal injury) or fluid percussion injury (FPI; a diffuse injury) in rats. The rationale for this comparative analysis was to investigate the brain's response to mild diffuse versus mild focal injury to identify common molecular changes triggered by these injury modalities and to determine the functional pathways altered after injury that may provide novel targets for therapeutic intervention. Microarrays containing probes against 21,792 unique messenger RNAs (mRNAs) were used to investigate the changes in cortical mRNA expression levels at 3 and 24 h postinjury. Of the 354 mRNAs with significantly altered expression levels after mCCI, over 89% (316 mRNAs) were also contained within the mild FPI (mFPI) data set. However, mFPI initiated a more widespread molecular response, with over 2300 mRNAs differentially expressed. Bioinformatic analysis of annotated gene ontology molecular function and biological pathway terms showed a significant overrepresentation of genes belonging to inflammation, stress, and signaling categories in both data sets. We therefore examined changes in the protein levels of a panel of 23 cytokines and chemokines in cortical extracts using a Luminex-based bead immunoassay and detected significant increases in macrophage inflammatory protein (MIP)-1α (CCL3), GRO-KC (CXCL1), interleukin (IL)-1α, IL-1β, and IL-6. Immunohistochemical localization of MIP-1α and IL-1β showed marked increases at 3 h postinjury in the cortical vasculature and microglia, respectively, that were largely resolved by 24 h postinjury. Our findings demonstrate that both focal and diffuse mTBI trigger many shared pathobiological processes (e.g., inflammatory responses) that could be targeted for mechanism-based therapeutic interventions.

Traumatic alterations in consciousness: traumatic brain injury

Mild traumatic brain injury (mTBI) refers to the clinical condition of transient alteration of consciousness as a result of traumatic injury to the brain. The priority of emergency care is to identify and facilitate the treatment of rare but potentially life-threatening intracranial injuries associated with mTBI through the judicious application of appropriate imaging studies and neurosurgical consultation. Although post-mTBI symptoms quickly and completely resolve in the vast majority of cases, a significant number of patients will complain of lasting problems that may cause significant disability. Simple and early interventions such as patient education and appropriate referral can reduce the likelihood of chronic symptoms. Although definitive evidence is lacking, mTBI is likely to be related to significant long-term sequelae such as Alzheimer disease and other neurodegenerative processes.

Relationships among post-concussive symptoms and symptoms of PTSD in children following mild traumatic brain injury

PRIMARY OBJECTIVE

To investigate the occurrence of post-concussive symptoms (PCS) and symptoms of post-traumatic stress disorder (PTSD) in children following mild traumatic brain injuries (TBI).

RESEARCH DESIGN

Longitudinal study comparing the outcomes of mild TBI and orthopaedic injuries (OI) in children aged 8-15.

METHODS AND PROCEDURES

One hundred and eighty-six children with mild TBI and 99 with OI were recruited prospectively. Parents rated children's PCS and symptoms of PTSD at 2 weeks, 3 months and 12 months post-injury. One hundred and sixty-seven with mild TBI and 84 with OI completed all assessments.

MAIN OUTCOMES AND RESULTS

Controlling for symptoms of PTSD, the mild TBI group demonstrated more PCS than the OI group, although the magnitude of group differences diminished with time. Controlling for PCS, the OI group displayed more symptoms of PTSD than the mild TBI group at baseline, but not thereafter. Symptoms of PTSD and PCS were correlated significantly, but more highly in the OI group than the mild TBI group.

CONCLUSIONS

Although PCS and symptoms of PTSD are correlated, children with mild TBI are more distinguishable from children with OI based on PCS than on symptoms of PTSD. The latter symptoms, moreover, do not account for increased PCS following mild TBI in children.

Sex differences in outcome after mild traumatic brain injury

The objective of this study was to estimate the independent association of sex with outcome after mild traumatic brain injury (mTBI). We performed an analysis of a subset of an established cohort involving 1425 mTBI patients presenting to an academic emergency department (ED). The associations between sex and three outcomes determined 3 months after the initial ED visit were examined: post-concussive symptom (PCS) score (0, 1-5, 6-16, and >16), the number of days to return of normal activities (0, 1-7, and >7), and the number of days of work missed (0, 1-7,and >7). Logistic regression analyses were used to determine the relationship between sex and each outcome after controlling for 12 relevant subject-level variables. Of the 1425 subjects, 643 (45.1%) were female and 782 (54.9%) were male. Three months after mTBI, males had significantly lower odds of being in a higher PCS score category (odds ratio [OR] 0.62, 95% confidence interval [CI]: 0.50, 0.78); this association appeared to be more prominent during child-bearing years for females. Males and females did not significantly differ with respect to the odds of poorer outcome as defined by the number of days to return of normal activities or the number of days of work missed. Female sex is associated with significantly higher odds of poor outcome after mTBI, as measured by PCS score, after control for appropriate confounders. The observed pattern of peak disability for females during the child-bearing years suggests disruption of endogenous estrogen or progesterone production. Attempts to better understand how mTBI affects production of these hormones acutely after injury and during the recovery period may shed light on the mechanism behind poorer outcome among females and putative therapeutic interventions.

Bomb blast, mild traumatic brain injury and psychiatric morbidity: a review

Traumatic brain injury (TBI) arising from blast exposure during war is common, and frequently complicated by psychiatric morbidity. There is controversy as to whether mild TBI from blast is different from other causes of mild TBI. Anxiety and affective disorders such as Post-traumatic Stress Disorder (PTSD) and depression are common accompaniments of blast injury with a significant overlap in the diagnostic features of PTSD with post-concussive syndrome (PCS). This review focuses on this overlap and the effects of mild TBI due to bomb blast. Mild TBI may have been over diagnosed by late retrospective review of returned servicemen and women using imprecise criteria. There is therefore a requirement for clear and careful documentation by health professionals of a TBI due to bomb blast shortly after the event so that the diagnosis of TBI can be made with confidence. There is a need for the early recognition of symptoms of PCS, PTSD and depression and early multi-disciplinary interventions focussed on expected return to duties. There also needs to be a continued emphasis on the de-stigmatization of psychological conditions in military personnel returning from deployment.

Long-term psychiatric outcomes following traumatic brain injury: a review of the literature

OBJECTIVE

To determine the relationship between traumatic brain injury (TBI) and long-term psychiatric health outcomes, occurring 6 months or more after TBI.

PARTICIPANTS

Not applicable.

DESIGN

Systematic review of the published, peer-reviewed literature.

PRIMARY MEASURES

Not applicable.

RESULTS

We identified studies that examined psychiatric disorders following TBI. There was sufficient evidence of an association between TBI and depression and similarly compelling evidence of an association between TBI and aggression. There was limited/suggestive evidence of an association between TBI and subsequent completed suicide, decreased alcohol and drug use compared to preinjury levels, and psychosis. While there was also limited/suggestive evidence for posttraumatic stress disorder (PTSD) in military populations with TBI, there was inadequate evidence to reach a conclusion about whether TBI was associated with PTSD in civilian populations.

CONCLUSION

TBI is associated with a wide range of psychiatric disorders among individuals surviving at least 6 months. The association between mild TBI and PTSD seems to differ in military and civilian populations.

Head injury as a PTSD predictor among Oklahoma City bombing survivors

BACKGROUND

The aim of the Oklahoma City (OKC) bombing retrospective review was to investigate the relationship between physical injury, environmental contributors, and psychiatric disorders such as posttraumatic stress disorder (PTSD) in an event-based, matched design study focused on injury.

METHODS

The 182 selected participants were a random subset of the 1,092 direct survivors from the OKC bombing. Only 124 of these 182 cases had a full complement of medical/clinical data in the OKC database. These 124 cases were assessed to explore relationships among PTSD diagnoses, levels of blast exposure, and physical injuries. Associations among variables were statistically tested using contingency analysis and logistic regression.

RESULTS

Comparison of the PTSD cases to symptoms/diagnoses reported in the medical records reveals a statistically significant association between PTSD and head/brain injuries associated with head acceleration. PTSD was not highly correlated with other injuries. Although blast pressure and impulse were highly correlated with head injuries, the correlation with PTSD was not statistically significant. Thus, a correlation between blast pressure and PTSD may exist, but higher fidelity pressure calculations are required to elucidate this potential relationship.

CONCLUSIONS

This study provides clear evidence that head injury is associated with subsequent PTSD, giving caregivers' information on what physical injuries may suggest the development of psychologic disorders to aid them in developing a profile for the identification of future survivors of terrorist attacks and Warfighters with brain injuries and potential PTSD.

Early stage assessment and course of acute stress disorder after mild traumatic brain injury

Although it has been established that acute stress disorder (ASD) and posttraumatic stress disorder occur after mild traumatic brain injury (MTBI) the qualitative differences in symptom presentation between injury survivors with and without a MTBI have not been explored in depth. This study aimed to compare the ASD and posttraumatic stress disorder symptom presentation of injury survivors with and without MTBI. One thousand one hundred sixteen participants between the ages of 17 to 65 years (mean age: 38.97 years, SD: 14.23) were assessed in the acute hospital after a traumatic injury. Four hundred seventy-five individuals met the criteria for MTBI. Results showed a trend toward higher levels of ASD in the MTBI group compared with the non-MTBI group. Those with a MTBI and ASD had longer hospital admissions and higher levels of distress associated with their symptoms. Although many of the ASD symptoms that the MTBI group scored significantly higher were also part of a postconcussive syndrome, higher levels of avoidance symptoms may suggest that this group is at risk for longer term poor psychological adjustment. Mild TBI patients may represent a injury group at risk for poor psychological adjustment after traumatic injury.

Psychiatric disorders and traumatic brain injury

Psychiatric disorders after traumatic brain injury (TBI) are frequent. Researches in this area are important for the patients' care and they may provide hints for the comprehension of primary psychiatric disorders. Here we approach epidemiology, diagnosis, associated factors and treatment of the main psychiatric disorders after TBI. Finally, the present situation of the knowledge in this field is discussed.

Neuropsychology and clinical neuroscience of persistent post-concussive syndrome

On the mild end of the acquired brain injury spectrum, the terms concussion and mild traumatic brain injury (mTBI) have been used interchangeably, where persistent post-concussive syndrome (PPCS) has been a label given when symptoms persist for more than three months post-concussion. Whereas a brief history of concussion research is overviewed, the focus of this review is on the current status of PPCS as a clinical entity from the perspective of recent advances in the biomechanical modeling of concussion in human and animal studies, particularly directed at a better understanding of the neuropathology associated with concussion. These studies implicate common regions of injury, including the upper brainstem, base of the frontal lobe, hypothalamic-pituitary axis, medial temporal lobe, fornix, and corpus callosum. Limitations of current neuropsychological techniques for the clinical assessment of memory and executive function are explored and recommendations for improved research designs offered, that may enhance the study of long-term neuropsychological sequelae of concussion.

Memory of the traumatic event as a risk factor for the development of PTSD: lessons from the study of traumatic brain injury

Traumatic memories, and the mechanisms by which they operate, continue to occupy a central role in the scientific investigation of risk factors for the development of posttraumatic stress disorder (PTSD). However, empirically based studies are constrained by practical and ethical considerations and are limited to naturalistic models. Consequently, the paradigms most appropriate for the exploration of the relationship between traumatic memories and PTSD have been identified in conditions involving traumatic events where memories may be compromised. Indeed, traumatic brain injury, a condition that is commonly associated with memory impairment, has often been utilized as a naturally occurring model for the study of traumatic memory and its contribution to the development of PTSD. This article presents a critical review of these research efforts and discusses their theoretical and clinical implications.