Post-traumatic stress disorder vs traumatic brain injury

MicroRNAs as potential biomarkers for diagnosis of post-traumatic stress disorder

Post-traumatic stress disorder is a mental disorder caused by exposure to severe traumatic life events. Currently, there are no validated biomarkers or laboratory tests that can distinguish between trauma survivors with and without post-traumatic stress disorder. In addition, the heterogeneity of clinical presentations of post-traumatic stress disorder and the overlap of symptoms with other conditions can lead to misdiagnosis and inappropriate treatment. Evidence suggests that this condition is a multisystem disorder that affects many biological systems, raising the possibility that peripheral markers of disease may be used to diagnose post-traumatic stress disorder. We performed a PubMed search for microRNAs (miRNAs) in post-traumatic stress disorder (PTSD) that could serve as diagnostic biomarkers and found 18 original research articles on studies performed with human patients and published January 2012 to December 2023. These included four studies with whole blood, seven with peripheral blood mononuclear cells, four with plasma extracellular vesicles/exosomes, and one with serum exosomes. One of these studies had also used whole plasma. Two studies were excluded as they did not involve microRNA biomarkers. Most of the studies had collected samples from adult male Veterans who had returned from deployment and been exposed to combat, and only two were from recently traumatized adult subjects. In measuring miRNA expression levels, many of the studies had used microarray miRNA analysis, miRNA Seq analysis, or NanoString panels. Only six studies had used real time polymerase chain reaction assay to determine/validate miRNA expression in PTSD subjects compared to controls. The miRNAs that were found/validated in these studies may be considered as potential candidate biomarkers for PTSD and include miR-3130-5p in whole blood; miR-193a-5p, -7113-5p, -125a, -181c, and -671-5p in peripheral blood mononuclear cells; miR-10b-5p, -203a-3p, -4488, -502-3p, -874-3p, -5100, and -7641 in plasma extracellular vesicles/exosomes; and miR-18a-3p and -7-1-5p in blood plasma. Several important limitations identified in the studies need to be taken into account in future studies. Further studies are warranted with war veterans and recently traumatized children, adolescents, and adults having PTSD and use of animal models subjected to various stressors and the effects of suppressing or overexpressing specific microRNAs.

Incidence of anxiety after traumatic brain injury: a systematic review and meta-analysis

BACKGROUND

Traumatic brain injury (TBI) is defined as acquired cerebral damage caused by an external mechanical impact, which has the potential to lead to transient or enduring debilitation. TBI is associated with many forms of long-lasting psychiatric conditions, including anxiety disorders. As anxiety is highly debilitating by causing impaired social functioning and decreased quality of life for the afflicted, especially in the form of anxiety disorders such as generalized anxiety disorder, certain efforts have been made to explore the factors associated with it, and one such factor is TBI.

METHODS

We searched PubMed, Scopus, and Web of Science on January 26th, 2024 for observational case-control or cohort or cross-sectional studies assessing the incidence of anxiety symptoms or disorders in patients with TBI compared to healthy individuals or the same individuals if pre-TBI information regarding anxiety was available. We calculated the pooled incidence and relative risk (RR) and 95% confidence interval (95CI) using the inverse variance method. Publication bias was assessed using Eggers's regression test. Quality assessment was performed using the Newcastle-Ottawa scale. Sub-group analyses were conducted for the type of anxiety (anxiety disorder vs anxiety symptoms), TBI severity, and type of anxiety disorders.

RESULTS

The incidence rate of anxiety after traumatic brain injury was 17.45% (95CI: 12.59%, 22.31%) in a total of 705,024 individuals. Moreover, TBI patients were found to be 1.9 times as likely to have anxiety compared to their non-TBI counterparts [Random effects model RR = 1.90 [1.62; 2.23], p-value < 0.0001] using a population of 569,875 TBI cases and 1,640,312 non-TBI controls. Sub-group analysis revealed TBI severity was not associated with anxiety and generalized anxiety disorder was the most common type of anxiety disorder reported post-TBI.

CONCLUSION

Patients who have experienced a TBI exhibit a significantly greater incidence of anxiety symptoms and anxiety disorders in the aftermath when compared to healthy individuals.

Assessment of the Behaviors of an In Vitro Brain Model On-Chip under Shockwave Impacts

Herein we report the assessment of the effects of shockwave (SW) impacts on adult rat hippocampal progenitor cell (AHPC) neurospheres (NSs), which are used as in vitro brain models, for enhancing our understanding of the mechanisms of traumatic brain injury (TBI). The assessment has been achieved by using culture dishes and a new microchip. The microchip allows the chemicals released from the brain models cultured inside the cell culture chamber under SW impacts to diffuse to the nanosensors in adjacent sensor chambers through built-in diffusion barriers, which are used to prevent the cells from entering the sensor chambers, thereby mitigating the biofouling issues of the sensor surface. Experiments showed the negative impact of the SW on the viability, proliferation, and differentiation of the cells within the NSs. A qPCR gene expression analysis was performed and appeared to confirm some of the immunocytochemistry (ICC) results. Finally, we demonstrated that the microchip can be used to monitor lactate dehydrogenase (LDH) released from the AHPC-NSs subjected to SW impacts. As expected, LDH levels changed when AHPC-NSs were injured by SW impacts, verifying this chip can be used for assessing the degrees of injuries to AHPC-NSs by monitoring LDH levels. Taken together, these results suggest the feasibility of using the chip to better understand the interactions between SW impacts and in vitro brain models, paving the way for potentially establishing in vitro TBI models on a chip.

Anoxic Brain Injury: A Subtle and Often Overlooked Finding in Non-Fatal Intimate Partner Strangulation

BACKGROUND

A paucity of literature exists dedicated to the identification of anoxic brain injury in patients that survive non-fatal intimate partner strangulation (NF-IPS). While some individuals report experiencing symptoms of brain hypoxia followed by a loss of consciousness, other individuals report symptoms of brain hypoxia prior to amnesia, rendering some unable to recall loss of consciousness (LOC).

OBJECTIVE

Using a standardized clinical assessment tool, the purpose of this retrospective analysis is to describe anoxic brain injury symptom prevalence in a sample of patients reporting NF-IPS.

METHODS

One hundred and ninety-one unique patients, reporting a total of 267 strangulation events, were assessed by a member of the Shasta Community Forensic Care Team utilizing the Strangulation Hypoxia Anoxia Symptom TBI Assessment (SHASTA) tool. The sample is 98% female and includes adult patients ages 18-68. Examination records were categorized based on the presence or absence of hypoxia and anoxia symptoms. This manuscript utilizes the STROBE checklist.

RESULTS

Amnesia was reported in 145 of the 267 strangulations (54.3%). Of those, 74 reported LOC (51.0%) while 71 did not recall LOC (49.0%).

CONCLUSIONS

Within our sample, 49% of patients with amnesia did not recall losing consciousness, demonstrating that LOC is an imperfect measure of anoxia for patients following NF-IPS. Healthcare providers examining NF-IPS patients should inquire about additional symptoms of hypoxia and amnesia, which can be captured on the SHASTA tool.

Clinician perspectives on characteristics and care of traumatic brain injury among asylum seekers and refugees

PURPOSE

Traumatic brain injury (TBI) disproportionately affects asylum-seekers and refugees (ASR), although underdiagnosed and undertreated. Our study assesses clinicians' perspectives on characteristics and management of TBI among ASR, with the hope of improving TBI management in this population.

MATERIALS AND METHODS

We conducted six focus groups of 16 clinicians across two academic medical centers in Boston, Massachusetts, United States. Clinicians in our sample included primary care clinicians, nurse practitioners, social workers, psychologists, neurologists, psychiatrists, and neuropsychologists. We analyzed the qualitative data following a hybrid inductive-deductive thematic analytic approach.

RESULTS

Clinicians characterized TBI among ASR as mostly mild and remote, involving head strikes, perpetrated predominantly by interpersonal violence and strangulation-related brain injury, and involving symptom overlap with mental health diagnoses, challenging diagnosis. Clinicians also described inadequate screening, the importance of connecting the physical and psychological symptoms of the brain injury rather than viewing them as distinct, and addressing diagnosis-related stigma and shame. Finally, they discussed lack of TBI-specific knowledge among providers and patients alike, and resource limitations affecting the continuum of care for this population.

CONCLUSION

Integrating clinicians' perspectives in caring for this population allows us to best meet their needs, including in TBI recovery.

An overview of preclinical models of traumatic brain injury (TBI): relevance to pathophysiological mechanisms

Background

Traumatic brain injury (TBI) is a major cause of morbidity and mortality, affecting millions annually worldwide. Although the majority of TBI patients return to premorbid baseline, a subset of patient can develop persistent and often debilitating neurocognitive and behavioral changes. The etiology of TBI within the clinical setting is inherently heterogenous, ranging from sport related injuries, fall related injuries and motor vehicle accidents in the civilian setting, to blast injuries in the military setting.

Objective

Animal models of TBI, offer the distinct advantage of controlling for injury modality, duration and severity. Furthermore, preclinical models of TBI have provided the necessary temporal opportunity to study the chronic neuropathological sequelae of TBI, including neurodegenerative sequelae such as tauopathy and neuroinflammation within the finite experimental timeline. Despite the high prevalence of TBI, there are currently no disease modifying regimen for TBI, and the current clinical treatments remain largely symptom based. The preclinical models have provided the necessary biological substrate to examine the disease modifying effect of various pharmacological agents and have imperative translational value.

Methods

The current review will include a comprehensive survey of well-established preclinical models, including classic preclinical models including weight drop, blast injury, fluid percussion injury, controlled cortical impact injury, as well as more novel injury models including closed-head impact model of engineered rotational acceleration (CHIMERA) models and closed-head projectile concussive impact model (PCI). In addition to rodent preclinical models, the review will include an overview of other species including large animal models and Drosophila.

Results

There are major neuropathological perturbations post TBI captured in various preclinical models, which include neuroinflammation, calcium dysregulation, tauopathy, mitochondrial dysfunction and oxidative stress, axonopathy, as well as glymphatic system disruption.

Conclusion

The preclinical models of TBI continue to offer valuable translational insight, as well as essential neurobiological basis to examine specific disease modifying therapeutic regimen.

Maternal deprivation causes CaMKII downregulation and modulates glutamate, norepinephrine and serotonin in limbic brain areas in a rat model of single prolonged stress

BACKGROUND

Early life stress is a major risk factor for later development of psychiatric disorders, including post-traumatic stress disorder (PTSD). An intricate relationship exists between various neurotransmitters (such as glutamate, norepinephrine or serotonin), calcium/calmodulin-dependent protein kinase II (CaMKII), as an important regulator of glutamatergic synaptic function, and PTSD. Here, we developed a double-hit model to investigate the interaction of maternal deprivation (MD) as an early life stress model and single prolonged stress (SPS) as a PTSD model at the behavioral and molecular levels.

METHODS

Male Wistar rats exposed to these stress paradigms were subjected to a comprehensive behavioral analysis. In hippocampal synaptosomes we investigated neurotransmitter release and glutamate concentration. The expression of CaMKII and the content of monoamines were determined in selected brain regions. Brain-derived neurotrophic factor (BDNF) mRNA was quantified by radioactive in situ hybridization.

RESULTS

We report a distinct behavioral phenotype in the double-hit group. Double-hit and SPS groups had decreased hippocampal presynaptic glutamatergic function. In hippocampus, double-hit stress caused a decrease in autophosphorylation of CaMKII. In prefrontal cortex, both SPS and double-hit stress had a similar effect on CaMKII autophosphorylation. Double-hit stress, rather than SPS, affected the norepinephrine and serotonin levels in prefrontal cortex, and suppressed BDNF gene expression in prefrontal cortex and hippocampus.

LIMITATIONS

The study was conducted in male rats only. The affected brain regions cannot be restricted to hippocampus, prefrontal cortex and amygdala.

CONCLUSION

Double-hit stress caused more pronounced and distinct behavioral, molecular and functional changes, compared to MD or SPS alone.

Neurobiochemical Disturbances in Psychosis and their Implications for Therapeutic Intervention

Psychosis, marked by the emergence of psychotic symptoms, delves into the intricate dance of neurotransmitter dynamics, prominently featuring dopamine as a key orchestrator. In individuals living with psychotic conditions, the finely tuned balance of dopamine becomes disrupted, setting off a cascade of perceptual distortions and the manifestation of psychotic symptoms. A lot of factors can impact dopamine metabolism, further complicating its effects. From genetic predispositions to environmental stressors and inflammation, the delicate equilibrium is susceptible to various influences. The sensorium, the origin of incoming information, loses its intrinsic valence in this complex interplay. The concept of the "signal-to-noise ratio" encapsulates dopamine's role as a molecular switch in neural networks, influencing the flow of information serving the basic biological functions. This nuanced modulation acts as a cognitive prism, shaping how the world is perceived. However, in psychosis, this balance is disrupted, steering individuals away from a shared reality. Understanding dopamine's centrality requires acknowledging its unique status among neurotransmitters. Unlike strictly excitatory or inhibitory counterparts, dopamine's versatility allows it to toggle between roles and act as a cognitive director in the neural orchestra. Disruptions in dopamine synthesis, exchange, and receptor representation set off a chain reaction, impacting the delivery of biologically crucial information. The essence of psychosis is intricately woven into the delicate biochemical ballet choreographed by dopamine. The disruption of this neurotransmitter not only distorts reality but fundamentally reshapes the cognitive and behavioral field of our experience. Recognizing dopamine's role as a cognitive prism provides vital insights into the multifaceted nature of psychotic conditions, offering avenues for targeted therapeutic interventions aimed at restoring this delicate neurotransmitter balance.

Recent advances in the role of miRNAs in post-traumatic stress disorder and traumatic brain injury

Post-traumatic stress disorder (PTSD) is usually considered a psychiatric disorder upon emotional trauma. However, with the rising number of conflicts and traffic accidents around the world, the incidence of PTSD has skyrocketed along with traumatic brain injury (TBI), a complex neuropathological disease due to external physical force and is also the most common concurrent disease of PTSD. Recently, the overlap between PTSD and TBI is increasingly attracting attention, as it has the potential to stimulate the emergence of novel treatments for both conditions. Of note, treatments exploiting the microRNAs (miRNAs), a well-known class of small non-coding RNAs (ncRNAs), have rapidly gained momentum in many nervous system disorders, given the miRNAs' multitudinous and key regulatory role in various biological processes, including neural development and normal functioning of the nervous system. Currently, a wealth of studies has elucidated the similarities of PTSD and TBI in pathophysiology and symptoms; however, there is a dearth of discussion with respect to miRNAs in both PTSD and TBI. In this review, we summarize the recent available studies of miRNAs in PTSD and TBI and discuss and highlight promising miRNAs therapeutics for both conditions in the future.

Prevalence of comorbidities post mild traumatic brain injuries: a traumatic brain injury model systems study

Traumatic brain injury (TBI) is associated with an increased risk of long-lasting health-related complications. Survivors of brain trauma often experience comorbidities which could further dampen functional recovery and severely interfere with their day-to-day functioning after injury. Of the three TBI severity types, mild TBI constitutes a significant proportion of total TBI cases, yet a comprehensive study on medical and psychiatric complications experienced by mild TBI subjects at a particular time point is missing in the field. In this study, we aim to quantify the prevalence of psychiatric and medical comorbidities post mild TBI and understand how these comorbidities are influenced by demographic factors (age, and sex) through secondary analysis of patient data from the TBI Model Systems (TBIMS) national database. Utilizing self-reported information from National Health and Nutrition Examination Survey (NHANES), we have performed this analysis on subjects who received inpatient rehabilitation at 5 years post mild TBI. Our analysis revealed that psychiatric comorbidities (anxiety, depression, and post-traumatic stress disorder (PTSD)), chronic pain, and cardiovascular comorbidities were common among survivors with mild TBI. Furthermore, depression exhibits an increased prevalence in the younger compared to an older cohort of subjects whereas the prevalence of rheumatologic, ophthalmological, and cardiovascular comorbidities was higher in the older cohort. Lastly, female survivors of mild TBI demonstrated increased odds of developing PTSD compared to male subjects. The findings of this study would motivate additional analysis and research in the field and could have broader implications for the management of comorbidities after mild TBI.

Lifetime posttraumatic stress disorder as a predictor of mortality: a systematic review and meta-analysis

BACKGROUND

Posttraumatic Stress Disorder (PTSD) could potentially increase the risk of mortality, and there is a need for a meta-analysis to quantify this association. This study aims to determine the extent to which PTSD is a predictor of mortality.

METHODS

EMBASE, MEDLINE, and PsycINFO were searched systematically on 12th February 2020, with updated searches conducted in July 2021, and December 2022 (PROSPERO CRD42019142971). Studies involving community-dwelling participants with a diagnosis of PTSD or PTSD symptoms, and a comparator group of individuals without PTSD, and which assessed mortality risk, were included. A random-effects meta-analysis was conducted on studies reporting Odds Ratio (OR), Hazard Ratio (HR), and Risk Ratio (RR), and subgroup analysis was also performed by age, sex, type of trauma experienced, PTSD diagnosis, and cause of death.

RESULTS

A total of 30 eligible studies of mostly good methodological quality were identified, with a total of more than 2.1 million participants with PTSD. The majority of studies involved male-dominated, veteran populations. PTSD was associated with a 47% (95% CI: 1.06-2.04) greater risk of mortality across six studies that reported OR/RR, and a 32% increased risk across 18 studies which reported time to death (HR: 1.32, 95% CI: 1.10-1.59). There was very high study heterogeneity (I2 > 94%) and this was not explained by the prespecified subgroup analysis.

CONCLUSION

PTSD is associated with increased mortality risk, however further research is required amongst civilians, involving women, and in individuals from underdeveloped countries.

A comparison of the functional connectome in mild traumatic brain injury and post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) often co-occur in the context of threat to one's life. These conditions also have an overlapping symptomatology and include symptoms of anxiety, poor concentration and memory problems. A major challenge has been articulating the underlying neurobiology of these overlapping conditions. The primary aim of this study was to compare intrinsic functional connectivity between mTBI (without PTSD) and PTSD (without mTBI). The study included functional MRI data from 176 participants: 42 participants with mTBI, 67 with PTSD and a comparison group of 66 age and sex-matched healthy controls. We used network-based statistical analyses for connectome-wide comparisons of intrinsic functional connectivity between mTBI relative to PTSD and controls. Our results showed no connectivity differences between mTBI and PTSD groups. However, we did find that mTBI had significantly reduced connectivity relative to healthy controls within an extensive network of regions including default mode, executive control, visual and auditory networks. The mTBI group also displayed hyperconnectivity between dorsal and ventral attention networks and perceptual regions. The PTSD group also demonstrated abnormal connectivity within these networks relative to controls. Connectivity alterations were not associated with severity of PTSD or post-concussive symptoms in either clinical group. Taken together, the similar profiles of intrinsic connectivity alterations in these two conditions provide neural evidence that can explain, in part, the overlapping symptomatology between mTBI and PTSD.

Prevalence and correlates of self-reported cognitive difficulties in deployment-injured U.S. military personnel

Cognitive difficulties typically resolve within days to weeks following mild traumatic brain injury (mTBI); however, a sizable proportion of individuals continue to report cognitive symptoms months to years later that are often associated with posttraumatic stress disorder (PTSD) and depression to a greater degree than a history of mTBI. The current study sought to evaluate the prevalence of self-reported cognitive difficulties as well as the relative contributions of demographic, injury-related, and mental health variables in a large study of U.S. military personnel injured during deployment since 2001. Slightly fewer than half (42.0%) of participants reported elevated cognitive difficulties compared with a normative population; however, this was driven primarily by those who screened positive for PTSD or depression. Hierarchical linear regression revealed that various demographic and injury factors, including lower educational attainment, retired or separated military status, enlisted rank, and a history of deployment-related mTBI, were associated with more self-reported cognitive difficulties, f² = 0.07. Screening positive for PTSD or depression accounted for 32.1% of the variance in self-reported cognitive symptoms, f² = 0.63, whereas injury variables, including a history of deployment-related mTBI, albeit significant in the model, accounted for 1.6%. The current findings add to the growing body of literature underscoring the importance of screening for and treating mental health conditions in injured military personnel.

Enhanced Performance by Interpretable Low-Frequency Electroencephalogram Oscillations in the Machine Learning-Based Diagnosis of Post-traumatic Stress Disorder

Electroencephalography (EEG)-based diagnosis of psychiatric diseases using machine-learning approaches has made possible the objective diagnosis of various psychiatric diseases. The objective of this study was to improve the performance of a resting-state EEG-based computer-aided diagnosis (CAD) system to diagnose post-traumatic stress disorder (PTSD), by optimizing the frequency bands used to extract EEG features. We used eyes-closed resting-state EEG data recorded from 77 PTSD patients and 58 healthy controls (HC). Source-level power spectrum densities (PSDs) of the resting-state EEG data were extracted from 6 frequency bands (delta, theta, alpha, low-beta, high-beta, and gamma), and the PSD features of each frequency band and their combinations were independently used to discriminate PTSD and HC. The classification performance was evaluated using support vector machine with leave-one-out cross validation. The PSD features extracted from slower-frequency bands (delta and theta) showed significantly higher classification performance than those of relatively higher-frequency bands. The best classification performance was achieved when using delta PSD features (86.61%), which was significantly higher than that reported in a recent study by about 13%. The PSD features selected to obtain better classification performances could be explained from a neurophysiological point of view, demonstrating the promising potential to develop a clinically reliable EEG-based CAD system for PTSD diagnosis.

Expanding the Scope of Forensic and Other Services for Justice-Involved Veterans

Military veterans are a unique population within the criminal justice system. Numerous criminal justice reforms for this population exist, but there is a dearth of research summarizing and critiquing past and ongoing efforts directed at veterans. This article examines the partnerships developed by the Department of Veterans Affairs with criminal justice agencies to address the needs of justice-involved veterans. Despite these efforts, there is more to be done to support veterans. We provide recommendations for agencies, including enhanced identification of veterans in criminal justice settings, delivery of services to a wider range of veterans, enhancement of partnered relationships with law enforcement, recalibration of the role of Veterans Treatment Courts in the continuum of justice system offerings, expansion of trauma-informed care throughout the criminal justice and partnered health care systems, and sustainment of reform efforts and innovations through advisory bodies. Rigorous research to evaluate reform efforts are needed across all areas. The Veterans Affairs' continuing role as partner to criminal justice agencies and in reform efforts is critical, and improving linkage to and use of health care will result in enhanced health and other outcomes for veterans involved in the criminal justice system.

Emotion Dysregulation Following Trauma: Shared Neurocircuitry of Traumatic Brain Injury and Trauma-Related Psychiatric Disorders

The psychological trauma associated with events resulting in traumatic brain injury (TBI) is an important and frequently overlooked factor that may impede brain recovery and worsen mental health following TBI. Indeed, individuals with comorbid posttraumatic stress disorder (PTSD) and TBI have significantly poorer clinical outcomes than individuals with a sole diagnosis. Emotion dysregulation is a common factor leading to poor cognitive and affective outcomes following TBI. Here, we synthesize how acute postinjury molecular processes stemming from either physical or emotional trauma may adversely impact circuitry subserving emotion regulation and ultimately yield long-term system-level functional and structural changes that are common to TBI and PTSD. In the immediate aftermath of traumatic injury, glucocorticoids stimulate excess glutamatergic activity, particularly in prefrontal cortex-subcortical circuitry implicated in emotion regulation. In human neuroimaging work, assessing this same circuitry well after the acute injury, TBI and PTSD show similar impacts on prefrontal and subcortical connectivity and activation. These neural profiles indicate that emotion regulation may be a useful target for treatment and early intervention to prevent the adverse sequelae of TBI. Ultimately, the success of future TBI and PTSD early interventions depends on the fields' ability to address both the physical and emotional impact of physical injury.

"We have no magic bullet": Diagnostic ideals in veterans' mild traumatic brain injury evaluations

OBJECTIVE

To understand military veterans' and healthcare providers' experiences identifying veterans' personal histories of combat-related mild traumatic brain injury (mTBI) months or years after the injury.

METHODS

Patients and clinical staff of a Veterans Health Administration (VA) Polytrauma/TBI clinic participated in a seven-month ethnographic study, which combined direct observation and interviews with veterans (n = 12) and VA clinicians (n = 11). Data were analyzed thematically.

RESULTS

Veterans and staff have different understandings of the value of neuroimaging in care for patients with post-acute mTBI, and different understandings of the role of diagnostic certainty in clinical care. Veterans sought to understand the relationship between their past head injuries and their current symptoms. Clinicians educated veterans that their symptoms could be caused by multiple factors and embraced ambiguity as part of treating this patient population.

CONCLUSIONS

Patient-provider communication may be enhanced by conversations about common norms of diagnosis and why evaluating mTBI histories departs from these norms.

PRACTICE IMPLICATIONS

Clinicians should anticipate that patients may expect a diagnostic process that entails neuroimaging and resolves their uncertainty. In the case of post-acute mTBI, patients would likely benefit from education about the diagnostic process, itself.

TINY IN SIZE, BIG IN IMPACT: EXTRACELLULAR VESICLES AS MODULATORS OF MOOD, ANXIETY AND NEURODEVELOPMENTAL DISORDERS

Extracellular Vesicles (EVs) are tiny vesicles used by cells as means of cellular communication, through which the function and state of a given cell can be changed. A body of evidence has suggested that EVs could be culprits in the development and progression of various types of diseases, including neurodegenerative diseases such as Multiple Sclerosis (MS) and Alzheimer's Disease (AD). Unsurprisingly, EVs have also been implicate in mood, anxiety and neurodevelopmental disorders, such as Major Depressive Disorder (MDD), anxiety disorder and Autism-Spectrum Disorder (ASD), respectively. Here, we review the state-of-art regarding the roles of EVs in the aforementioned diseases and focus on the mechanisms by which they can cause and worsen disease. Harnessing the knowledge of EVs is not only important to deliver different cargos to cells in a specific manner to treat these diseases, but also to establish reliable disease biomarkers, which will aid in the early disease diagnosis and treatment, increasing the chance of successful treatment.

Shorter Telomeres Related to Posttraumatic Stress Disorder Re-experiencing Symptoms in Sexually Assaulted Civilian Women

Telomeres are short tandem repeats of "TTAGGG" that protect the chromosome ends from deterioration or fusion of chromosomes. Their repeat length shortens with cell division acting as a biomarker of cellular aging. Traumatic stress events during adulthood or childhood have been associated with posttraumatic stress disorder (PTSD) and short leukocyte telomere length (LTL). This study investigated whether LTL was associated with PTSD in a Brazilian sample of sexually assaulted civilian women at two time points: baseline and 1-year follow-up. At baseline, we assessed 64 women with PTSD following sexual assault (cases) and 60 women with no previous history of sexual trauma or mental disorders (healthy controls - HC). At follow-up visit, 13 persistent PTSD cases, 11 HCs, and 11 PTSD remitters patients were evaluated. PTSD diagnosis and severity were assessed using Mini International Neuropsychiatric Interview (Diagnostic and Statistical Manual of Mental Disorders III/IV criteria) and Clinician-Administered PTSD Scale for DSM-5 (CAPS-5), respectively. LTL was measured using multiplex real-time polymerase chain reaction (PCR). In the baseline analysis, we observed that LTL was associated with re-experiencing symptoms (B = -0.16; confidence interval (CI) 95% = -0.027--0.005; Bonferroni-adjusted p-value = 0.02), but no association was observed between other PTSD symptoms and LTL. In the longitudinal analysis, telomere shortening was no longer observed in patients with PTSD and PTSD remitters. In conclusion, our findings indicate that shorter baseline LTL is associated with early stage of PTSD re-experiencing symptoms in recently sexually assaulted women.

Association Between Self-Reported Disability and Lifetime History of Traumatic Brain Injury With Loss of Consciousness Among Veterans and Nonveterans in North Carolina

BACKGROUND

Compared with civilians, service members and veterans who have a history of traumatic brain injury (TBI) are more likely to experience poorer physical and mental health. To investigate this further, this article examines the association between self-reported history of TBI with loss of consciousness and living with 1 or more current disabilities (ie, serious difficulty with hearing, vision, cognition, or mobility; any difficulty with self-care or independent living) for both veterans and nonveterans.

METHODS

A cross-sectional study using data from the North Carolina Behavioral Risk Factor Surveillance System for 4733 veterans and nonveterans aged 18 years and older.

RESULTS

Approximately 34.7% of veterans residing in North Carolina reported having a lifetime history of TBI compared with 23.6% of nonveterans. Veterans reporting a lifetime history of TBI had a 1.4 times greater risk of also reporting living with a current disability (adjusted prevalence ratio = 1.4; 95% confidence interval, 1.2-1.8) compared with nonveterans. The most common types of disabilities reported were mobility, cognitive, and hearing.

CONCLUSIONS

Compared with nonveterans, veterans who reported a lifetime history of TBI had an increased risk of reporting a current disability. Future studies, such as longitudinal studies, may further explore this to inform the development of interventions.

Post-traumatic Stress Disorder after Severe Traumatic Brain Injury: A Systematic Review

OBJECTIVE

The review aimed to summarize the existing knowledge base regarding post-traumatic stress disorder after severe traumatic brain injury (TBI) and try to guide future research.

METHOD

Web of Science, Scopus, and PubMed databases were used to identify original studies that explored the relationship between severe TBI and post-traumatic stress disorder.

RESULTS

A total of 13 studies were included in the review. They have been examined in terms of potentially compatible and incompatible mechanisms, as well as of possible confounding factors in relation to the diagnosis of post-traumatic stress disorder after severe TBI.

CONCLUSION

Only a few studies in the literature have addressed the present topic; therefore, the prevalence of post-traumatic stress disorder in patients with severe TBI still needs to be further investigated. In particular, future studies should be conducted only in severe TBI populations, considering their premorbid personality characteristics and their reactivity alteration. They should also obtain an accurate and appropriate assessment of post-traumatic stress disorder with clinical interviews as well as clarifying the role of post-traumatic amnesia in this population by incorporating control groups of patients.

Chronic Administration of 7,8-DHF Lessens the Depression-like Behavior of Juvenile Mild Traumatic Brain Injury Treated Rats at Their Adult Age

Traumatic brain injury (TBI) is a leading cause of mortality and morbidity among the global youth and commonly results in long-lasting sequelae, including paralysis, epilepsy, and a host of mental disorders such as major depressive disorder. Previous studies were mainly focused on severe TBI as it occurs in adults. This study explored the long-term adverse effect of mild TBI in juvenile animals (mTBI-J). Male Sprague Dawley rats received mTBI-J or sham treatment at six weeks old, then underwent behavioral, biochemical, and histological experiments three weeks later (at nine weeks old). TTC staining, H&E staining, and brain edema measurement were applied to evaluate the mTBI-J induced cerebral damage. The forced swimming test (FST) and sucrose preference test (SPT) were applied for measuring depression-like behavior. The locomotor activity test (LAT) was performed to examine mTBI-J treatment effects on motor function. After the behavioral experiments, the dorsal hippocampus (dHip) and ventral hippocampus (vHip) were dissected out for western blotting to examine the expression of brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB). Finally, a TrkB agonist 7,8-DHF was injected intraperitoneally to evaluate its therapeutic effect on the mTBI-J induced behavioral abnormalities at the early adult age. Results showed that a mild brain edema occurred, but no significant neural damage was found in the mTBI-J treated animals. In addition, a significant increase of depression-like behaviors was observed in the mTBI-J treated animals; the FST revealed an increase in immobility, and a decrease in sucrose consumption was found in the mTBI-J treated animals. There were no differences observed in the total distance traveled of the LAT and the fall latency of the rotarod test. The hippocampal BDNF expression, but not the TrkB, were significantly reduced in mTBI-J, and the mTBI-J treatment-induced depression-like behavior was lessened after four weeks of 7,8-DHF administration. Collectively, these results indicate that even a mild juvenile TBI treatment that did not produce motor deficits or significant histological damage could have a long-term adverse effect that could be sustained to adulthood, which raises the depression-like behavior in the adult age. In addition, chronic administration of 7,8-DHF lessens the mTBI-J treatment-induced depression-like behaviors in adult rats. We suggest the potential usage of 7,8-DHF as a therapeutic agent for preventing the long-term adverse effect of mTBI-J.

Chronic Anxiety- and Depression-Like Behaviors Are Associated With Glial-Driven Pathology Following Repeated Blast Induced Neurotrauma

Long-term neuropsychiatric impairments have become a growing concern following blast-related traumatic brain injury (bTBI) in active military personnel and Veterans. Neuropsychiatric impairments such as anxiety and depression are common comorbidities that Veterans report months, even years following injury. To understand these chronic behavioral outcomes following blast injury, there is a need to study the link between anxiety, depression, and neuropathology. The hippocampus and motor cortex (MC) have been regions of interest when studying cognitive deficits following blast exposure, but clinical studies of mood disorders such as major depressive disorder (MDD) report that these two regions also play a role in the manifestation of anxiety and depression. With anxiety and depression being common long-term outcomes following bTBI, it is imperative to study how chronic pathological changes within the hippocampus and/or MC due to blast contribute to the development of these psychiatric impairments. In this study, we exposed male rats to a repeated blast overpressure (~17 psi) and evaluated the chronic behavioral and pathological effects on the hippocampus and MC. Results demonstrated that the repeated blast exposure led to depression-like behaviors 36 weeks following injury, and anxiety-like behaviors 2-, and 52-weeks following injury. These behaviors were also correlated with astrocyte pathology (glial-fibrillary acid protein, GFAP) and dendritic alterations (Microtubule-Associated Proteins, MAP2) within the hippocampus and MC regions at 52 weeks. Overall, these findings support the premise that chronic glial pathological changes within the brain contribute to neuropsychiatric impairments following blast exposure.

The Mediating Role of Cognitive Processing in the Relationship Between Negative and Positive Effects of Trauma Among Female Victims of Domestic Violence

Exposure to domestic violence may lead not only to negative but also positive consequences of trauma. Negative effects are indicated by posttraumatic stress symptoms (PTSSs), and positive effects by posttraumatic growth (PTG) changes. PTG has been conceptualized to follow experiences of PTSSs. Therefore, the positive and negative effects of trauma appear to be related to one another. The cognitive processing may play a special role in determining whether the positive and negative consequences of trauma exposure are experienced. The aim of the study was to establish the mediating role of multiple patterns of cognitive processing, reflected by the cognitive strategies used to cope with trauma, in the relationship between negative and positive posttraumatic changes in women following domestic violence. Data were obtained from 63 Polish women who had experienced domestic violence. The age of the respondents ranged from 19 to 71 years (M = 42.25, SD = 14.81). The Polish versions of the following standardized tools were used: the Posttraumatic Stress Disorder Checklist (PCL-5), the Posttraumatic Growth Inventory (PTGI), and the Cognitive Processing of Trauma Scale (CPOTS). PTSS severity appeared to be negatively related to that of PTG. Negative coping strategies were positively related to the PTSS severity but negatively to PTG, while positive strategies were negatively related to the PTSS severity but positively to PTG. Cognitive strategies for coping with trauma, such as resolution/acceptance, downward comparison, and regret, appeared to play a mediating role in the relationship between PTSS severity and PTG. Positive coping strategies strengthen the occurrence of positive posttraumatic changes while strategy of regret weakens the PTG changes occurrence. The process of adaptation and human development among people who have experienced traumatic events is favored by the use of more frequent positive and less frequent negative strategies of dealing with trauma.

Localization of the hydrogen sulfide and oxytocin systems at the depth of the sulci in a porcine model of acute subdural hematoma

In the porcine model discussed in this review, the acute subdural hematoma was induced by subdural injection of autologous blood over the left parietal cortex, which led to a transient elevation of the intracerebral pressure, measured by bilateral neuromonitoring. The hematoma-induced brain injury was associated with albumin extravasation, oxidative stress, reactive astrogliosis and microglial activation in the ipsilateral hemisphere. Further proteins and injury markers were validated to be used for immunohistochemistry of porcine brain tissue. The cerebral expression patterns of oxytocin, oxytocin receptor, cystathionine-γ-lyase and cystathionine-β-synthase were particularly interesting: these four proteins all co-localized at the base of the sulci, where pressure-induced brain injury elicits maximum stress. In this context, the pig is a very relevant translational model in contrast to the rodent brain. The structure of the porcine brain is very similar to the human: the presence of gyri and sulci (gyrencephalic brain), white matter to grey matter proportion and tentorium cerebelli. Thus, pressure-induced injury in the porcine brain, unlike in the rodent brain, is reflective of the human pathophysiology.

The Impact of Neurocognitive Functioning on the Course of Posttraumatic Stress Symptoms following Civilian Traumatic Brain Injury

Background: One out of seven individuals who have suffered a traumatic brain injury (TBI) develops a posttraumatic stress disorder (PTSD), which is often associated with neurocognitive impairment. The present study explores the impact of neurocognitive functioning after mild, moderate, and severe TBI on the course of PTSD symptoms. Methods: The data of 671 adults admitted to hospital for a TBI was drawn from the Collaborative European Neurotrauma Effectiveness Research (CENTER-TBI) study. After six- and 12-months post-injury, participants completed the PTSD Checklist-5 (PCL-5), from which change scores were calculated. At six months, participants also completed a neurocognitive assessment including the Rey Auditory Verbal Learning Test, the Trail Making Test, and the Cambridge Neuropsychological Test Automated Battery (CANTAB). Linear regressions were performed to identify associations between cognitive functioning and PCL-5 change scores. Results: Overall, mean PCL-5 change scores showed no clear change (−0.20 ± 9.88), but 87 improved and 80 deteriorated by a change score of 10 or more. CANTAB Rapid Visual Information Processing scores were significantly associated with PCL-5 change scores. Conclusions: Strong sustained attention was associated with improvement in PTSD symptoms. Assessing cognitive performance may help identify individuals at risk of developing (persisting) PTSD post-TBI and offer opportunities for informing treatment strategies.

Altered Metabolic Interrelationships in the Cortico-Limbic Circuitry in Military Service Members with Persistent Post-Traumatic Stress Disorder Symptoms Following Mild Traumatic Brain Injury

Introduction: Comorbid mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are common in military service members. The aim of this study is to investigate brain metabolic interrelationships in service members with and without persistent PTSD symptoms after mTBI by using ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography. Methods: Service members (n = 408) diagnosed with mTBI were studied retrospectively. Principal component analysis was applied to identify latent metabolic systems, and the associations between metabolic latent systems and self-report measures of post-concussive and PTSD symptoms were evaluated. Participants were divided into two groups based on DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, fourth edition-Text Revision) criteria for PTSD, and structural equation modeling was performed to test a priori hypotheses on metabolic interrelationships among the brain regions in the cortico-limbic circuitry responsible for top-down control and bottom-up emotional processing. The differences in metabolic interrelationships between age-matched PTSD-absent (n = 204) and PTSD-present (n = 204) groups were evaluated. Results: FDG uptake in the temporo-limbic system was positively correlated with post-concussive and hyperarousal symptoms. For the bottom-up emotional processing, the insula and amygdala-hippocampal complex in the PTSD-present group had stronger metabolic interrelationships with the bilateral rostral anterior cingulate, left lingual, right lateral occipital, and left superior temporal cortices, but a weaker relationship with the right precuneus cortex, compared with the PTSD-absent group. For the top-down control, the PTSD-present group had decreased metabolic engagements of the dorsolateral prefrontal cortex on the amygdala. Discussion: Our results suggest altered metabolic interrelationships in the cortico-limbic circuitry in mTBI subjects with persistent PTSD symptoms, which may underlie the pathophysiological mechanisms of comorbid mTBI and PTSD. Impact statement This is the first ¹⁸F-fluorodeoxyglucose positron emission tomography study to investigate brain metabolic interrelationships in service members with persistent post-traumatic stress disorder (PTSD) symptoms after mild traumatic brain injury (mTBI). We identified that the temporo-limbic metabolic system was associated with post-concussive and hyperarousal symptoms. Further, brain metabolic interrelationships in the cortico-limbic circuitry were altered in mTBI subjects with significant PTSD symptoms compared with those without them.

Improving Outcomes for Work-Related Concussions: A Mental Health Screening and Brief Therapy Model

OBJECTIVE

This study assessed the efficacy of a neurocognitive screening evaluation and brief therapy model to improve RTW outcomes for workers who experienced mild head injuries.

METHODS

Patients referred were evaluated using a neurocognitive and psychological screening battery. Work-focused cognitive behavioral therapy was provided when appropriate, addressing the role of negative emotional adjustment and functional sleep disturbance in prolonging recovery.

RESULTS

Average time to RTW was 7 weeks post-evaluation, despite workers being off an average of 10 months between injury and referral dates. Overall, 99% were released to full-duty work without restrictions or accommodations.

CONCLUSIONS

This study demonstrates the favorable outcomes achieved via a structured, clinically driven program for workers who experience head-involved injuries, validating previous research on the importance of recognizing the role of psychological factors in prolonging concussion recovery.

Two-Step Resilience-Oriented Intervention for Veterans with Traumatic Brain Injury: A Pilot Randomized Controlled Trial

OBJECTIVE

The present randomized parallel two-arm pilot study aimed to compare the efficacy of two-step resilience-oriented intervention with treatment as usual in veterans with mild to moderate traumatic brain injury.

METHOD

Two-step Resilience-Oriented Intervention (TROI) is a brief psychological intervention that targets cognitive (step 1) and emotional (step 2) factors of resilience and consists of six 1-hour sessions. Overall, 70 Ukrainian veterans serviced in Anti-Terrorist Operation / Joint Forces Operation were randomly assigned to an intervention group (TROI group) or a control group that underwent treatment as usual (TAU group). For pre- (T1) and post-treatment (T2) assessment the Connor-Davidson Resilience Scale (CD-RISC), Hospital Anxiety and Depression Scale (HADS), Montreal Cognitive Assessment Scale (MoCA), Neurobehavioral Symptom Inventory (NSI), Posttraumatic Stress Disorder Checklist 5 (PCL-5), Chaban Quality of Life Scale (CQLS), Positive and Negative Affect Scale (PANAS) were used.

RESULTS

Multivariable linear regression with the treatment group, gender, baseline cognitive performance level and TBI severity as the independent variables revealed statistically significant improvements in the TROI group in resilience (CD-RISC), cognitive performance (MoCA), postconcussive symptoms (NSI), posttraumatic symptoms (PCL-5), positive affect (PANAS) and quality of life (CQLS) comparing to such in TAU group. We found no statistically significant differences between groups in depression, anxiety (HADS) and negative affect (PANAS) outcomes. Additionally, Wilcoxon signed-rank test revealed that participants who completed two-step resilience-oriented intervention had significantly improved scores for all outcomes compared to the baseline (p < 0.05).

CONCLUSIONS

In summary, we can tentatively conclude that adding TROI to the standard treatment measures may improve the resilience and sustainable symptoms in veterans with TBI when compared with standard treatment. Targeting cognitive and emotional factors like problem-solving, decision-making, positive thinking can promote resilience in veterans with TBI and be useful in facilitating recovery from injury. Results of this pilot study are promising, but the intervention needs to be studied in a larger trial.

Post-Concussion and Post-Traumatic Stress Symptoms after Pediatric Traumatic Brain Injury: Shared Vulnerability Factors?

Following pediatric traumatic brain injury (TBI), post-concussion symptoms (PCS) and post-traumatic stress symptoms (PTSS) occur commonly; however, it is unknown to what degree they overlap. The study examined PCS and PTSS persisting 7 weeks after injury in children and adolescents ages 8-15 years with TBI (n = 89) or extracranial injury (EI; n = 40) after vehicle collisions. TBI was divided into mild, complicated-mild/moderate, and severe groups. Parents retrospectively rated children's pre-injury symptoms and behavior problems, and children completed self-report measures after injury. PCS and PTSS total scores were significantly correlated in TBI and EI groups, respectively, for child (rs = 0.75; rs = 0.44), and adolescent (rs = 0.61; rs = 0.67) cohorts. Generalized linear models examined whether injury type and severity, age, sex, and pre-injury symptom ratings predicted PCS and PTSS total scores and factor scores. Specific PCS and PTSS factor scores were elevated in different TBI severity groups, with most frequent problems following mild or severe TBI. PCS did not differ by age; however, girls had more emotional symptoms than boys. Only PTSS were predicted by pre-injury externalizing behavior. Significant age by sex interactions indicated that adolescent girls had more total, avoidance, and hyperarousal PTSS symptoms than younger girls or all boys. PCS and PTSS significantly overlapped in both TBI and EI groups, highlighting shared persistent symptoms after injury. Shared vulnerability factors included female sex, milder TBI, and poorer pre-injury adjustment. Older age was a unique vulnerability factor for PTSS. Psychological health interventions after injury should be customized to address comorbid symptoms.

EMDR Treatment for Persistent Post-Concussion Symptoms Following Mild Traumatic Brain Injury: A Case Study

The majority of people who experience mild traumatic brain injury (mTBI) have a healthy recovery, where initial somatic, cognitive, psychological, and behavioral mTBI-related symptoms resolve naturally within hours or days. Unfortunately, a significant minority of people develop persistent post-concussion symptoms, sometimes referred to as persistent post-concussion syndrome (pPCS), often causing severe long-term reduction in well-being and daily function. Psychological and neuropsychological treatments are typically limited to antidepressants, psychoeducation on mTBI and pPCS, basic neurorehabilitative cognitive compensatory strategies, traditional cognitive behavioral therapy, or no treatment at all. This paper discusses a single case study which demonstrates how eye movement desensitization and reprocessing (EMDR) therapy might provide psychological improvement in clients who sustain mTBI and develop pPCS. The case example describes a 57-year-old man who sustained a mTBI from a serious road traffic collision as a pedestrian and who developed pPCS. Treatment included nine 1.5-hour EMDR sessions across a 5-month period (the first being an assessment). Measures of psychological symptom change and client feedback were taken at pretreatment, midtreatment, posttreatment, and aftertreatment had ceased to gauge long-term status. Measures were taken at 18-month follow-up and 4-year review (which followed litigation settlement). The novel viability for the application of EMDR for this client group isdiscussed.

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

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

Event related potentials indexing the influence of emotion on cognitive processing in veterans with comorbid post-traumatic stress disorder and traumatic brain injury

OBJECTIVE

Emotion regulation and cognitive executive control are significantly impaired in both post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI). These illnesses are increasingly common in veterans and their co-occurrence may exacerbate symptoms and recovery. The current study sought to investigate neural correlates of these impairments via event-related potentials (ERPs) and examined the association of PTSD symptom severity and impulsivity with these correlates.

METHODS

Electroencephalographic data from seventy-nine veterans with PTSD and TBI and 17 control participants were recorded during a visual emotional oddball task and analyzed for the N2 and P3b ERPs.

RESULTS

Results revealed that veterans showed a reduced P3b ERP in response to both target images and standard images. However, for standard images that followed a negative emotional distractor, the veterans showed a heightened N2 amplitude while the controls did not. In addition, impulsivity predicted modulation of the P3b across stimulus conditions, with a greater P3b amplitude associated with an increase in impulsivity.

CONCLUSIONS

These findings suggest that veterans showed hyper-responsivity to background information and reduced ERPs to task-relevant information.

SIGNIFICANCE

These findings may reflect heightened internal states that create neural noise and a reduced ability to modulate relevant responses.

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

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

Neural activity during response inhibition in mild traumatic brain injury and posttraumatic stress disorder

Mild traumatic brain injury (mTBI) is often characterized by deficits in response inhibition, which can contribute to marked social and occupational dysfunction. mTBI often occurs in the context of psychologically traumatic events. This can cause posttraumatic stress disorder (PTSD), which also impedes response inhibition. The overlap or distinction in these inhibitory deficits in mTBI and PTSD is unclear. This study aimed to assess behavioral, neurophysiological, and neuroimaging indices of response inhibition in mTBI by also assessing these parameters in healthy controls (HC) and PTSD participants. Participants with mTBI (without PTSD) (n = 46), PTSD (without mTBI) (n = 41), and HC (n = 40) were assessed during a response inhibition task (the Go/NoGo task) during neuropsychological testing and separate functional magnetic imaging and event-related potentials sessions. PTSD symptom severity was assessed with the Clinician-Administered PTSD Scale. Both mTBI and PTSD participants performed more omission errors on the Go/NoGo task and were associated with greater N2 amplitude, greater left inferior parietal activation and reduced connectivity of the left inferior parietal cluster and left angular gyrus compared to HC. There were no differences between mTBI and PTSD on any of these measures. These findings highlight that both mTBI and PTSD contribute to neural dysfunction during response inhibition, and arguably these occur due to distinct mechanisms. In the context of the common comorbidity between these two conditions, strategies to address response inhibition deficits in mTBI may need to consider causative factors underpinning neurological insult of mTBI and psychological effects associated with PTSD.

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

BACKGROUND

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

PURPOSE

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

METHODS

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

FINDINGS

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

DISCUSSION

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

Magnetoencephalography in the Detection and Characterization of Brain Abnormalities Associated with Traumatic Brain Injury: A Comprehensive Review

Magnetoencephalography (MEG) is a functional brain imaging technique with high temporal resolution compared with techniques that rely on metabolic coupling. MEG has an important role in traumatic brain injury (TBI) research, especially in mild TBI, which may not have detectable features in conventional, anatomical imaging techniques. This review addresses the original research articles to date that have reported on the use of MEG in TBI. Specifically, the included studies have demonstrated the utility of MEG in the detection of TBI, characterization of brain connectivity abnormalities associated with TBI, correlation of brain signals with post-concussive symptoms, differentiation of TBI from post-traumatic stress disorder, and monitoring the response to TBI treatments. Although presently the utility of MEG is mostly limited to research in TBI, a clinical role for MEG in TBI may become evident with further investigation.

A pilot study of brain injury in police officers: A source of mental health problems?

WHAT IS KNOWN ON THE SUBJECT?: Traumatic brain injury (TBI) has been linked to poor outcomes in terms of mental health, specifically, PTSD, depression and alcohol abuse. A lack of research evidence exists relevant to exploring the presence and implications of TBI in the police in the UK and globally, despite the elevated risk of physical and emotional trauma specific to policing. WHAT DOES THE PAPER ADD TO EXISTING KNOWLEDGE?: The rate of traumatic brain injury is highly prevalent in a small sample of police officers. Traumatic brain injury is a major source of post-concussion symptoms (physical, cognitive and emotional deficits) in police officers, which, in general, are associated with greater mental health difficulties and drinking alcohol to cope. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Traditional mental health treatments should be supplemented with elements of concussion care to address any cognitive, emotional and physical issues due to head injury. Interventions should be made more accessible to those suffering from a mild brain injury. This can be done through regular reminders of appointments, pictograms and by providing a concrete follow-up. ABSTRACT: Introduction Police officers have a high risk of injury through assaults, road traffic incidents and attending domestic calls, with many officers developing post-traumatic stress disorder (PTSD) as a consequence. Traumatic brain injury (TBI) is a common injury in populations involved in conflict and has been extensively linked to mental health difficulties. However, current research has not explored the frequency and sequelae of TBI in police populations, despite the elevated risk of physical and emotional trauma specific to policing. Aim To explore self-reported TBI, PTSD, post-concussion symptoms, depression and drinking to cope in a small sample of UK police, to determine the frequency of these conditions and their relationships. Method Measures of TBI, mental health, and drinking alcohol to cope were administered to 54 police officers from a Midshire Police Constabulary. Results Mild TBI with loss of consciousness was reported by 38.9% of the sample. TBI was associated with increased post-concussion symptoms (PCS). PCS were associated with greater severity of PTSD, depression and drinking to cope. Discussion Exploring TBI in the police could identify a major factor contributing towards ongoing mental health difficulties in a population where, based on previous research, the implications of TBI should not be overlooked, highlighting the need for further research in this area. Implications for Practice This research spans to identify the importance of routine assessment and increasing awareness within mental health services. Mental health treatments should be made amenable to a population with potential memory, planning and impulse control deficits. Further work in mental health services is needed to understand the level of ongoing issues that are due to post-concussion symptoms and those that are due to other mental health difficulties, such as PTSD, thereby educating patients on the association between TBI and emotional difficulties. A graduated return-to-work plan should be developed to enable a safe transition back to work, whilst managing any ongoing symptoms.

Cognitive deficits and rehabilitation mechanisms in mild traumatic brain injury patients revealed by EEG connectivity markers

OBJECTIVE

To explore the multiple specific biomarkers and cognitive compensatory mechanisms of mild traumatic brain injury (mTBI) patients at recovery stage.

METHODS

The experiment was performed in two sections. In Section I, using event-related potential, event-related oscillation and spatial phase-synchronization, we explored neural dynamics in 24 volunteered healthy controls (HC) and 38 patients at least 6 months post-mTBI (19 with epidural hematoma, EDH; 19 with subdural hematoma, SDH) during a Go/NoGo task. In Section II, according to the neuropsychological scales, patients were divided into sub-groups to assess these electroencephalography (EEG) indicators in identifying different rehabilitation outcomes of mTBI.

RESULTS

In Section I, mean amplitudes of NoGo-P3 and P3d were decreased in mTBI patients relative to HC, and NoGo-theta power in the non-injured hemisphere was decreased in SDH patients only. In Section II, patients with chronic neuropsychological defects exhibited more serious impairments of intra-hemispheric connectivity, whereas inter-hemispheric centro-parietal and frontal connectivity were enhanced in response to lesions.

CONCLUSIONS

EEG distinguished mTBI patients from healthy controls, and estimated different rehabilitation outcomes of mTBI. The centro-parietal and frontal connectivity are the main compensatory mechanism for the recovery of mTBI patients.

SIGNIFICANCE

EEG measurements and network connectivity can track recovery process and mechanism of mTBI.

A Workshop on Cognitive Aging and Impairment in the 9/11-Exposed Population

The terrorist attacks on 11 September 2001 potentially exposed more than 400,000 responders, workers, and residents to psychological and physical stressors, and numerous hazardous pollutants. In 2011, the World Trade Center Health Program (WTCHP) was mandated to monitor and treat persons with 9/11-related adverse health conditions and conduct research on physical and mental health conditions related to the attacks. Emerging evidence suggests that persons exposed to 9/11 may be at increased risk of developing mild cognitive impairment. To investigate further, the WTCHP convened a scientific workshop that examined the natural history of cognitive aging and impairment, biomarkers in the pathway of neurodegenerative diseases, the neuropathological changes associated with hazardous exposures, and the evidence of cognitive decline and impairment in the 9/11-exposed population. Invited participants included scientists actively involved in health-effects research of 9/11-exposed persons and other at-risk populations. Attendees shared relevant research results from their respective programs and discussed several options for enhancements to research and surveillance activities, including the development of a multi-institutional collaborative research network. The goal of this report is to outline the meeting's agenda and provide an overview of the presentation materials and group discussion.

Cerebrospinal fluid metabolomics identifies 19 brain-related phenotype associations

The study of metabolomics and disease has enabled the discovery of new risk factors, diagnostic markers, and drug targets. For neurological and psychiatric phenotypes, the cerebrospinal fluid (CSF) is of particular importance. However, the CSF metabolome is difficult to study on a large scale due to the relative complexity of the procedure needed to collect the fluid. Here, we present a metabolome-wide association study (MWAS), which uses genetic and metabolomic data to impute metabolites into large samples with genome-wide association summary statistics. We conduct a metabolome-wide, genome-wide association analysis with 338 CSF metabolites, identifying 16 genotype-metabolite associations (metabolite quantitative trait loci, or mQTLs). We then build prediction models for all available CSF metabolites and test for associations with 27 neurological and psychiatric phenotypes, identifying 19 significant CSF metabolite-phenotype associations. Our results demonstrate the feasibility of MWAS to study omic data in scarce sample types.

Repetitive Blast Promotes Chronic Aversion to Neutral Cues Encountered in the Peri-Blast Environment

Repetitive mild traumatic brain injury (mTBI) has been called the "signature injury" of military service members in the Iraq and Afghanistan wars and is highly comorbid with post-traumatic stress disorder (PTSD). Correct attribution of adverse blast-induced mTBI and/or PTSD remains challenging. Pre-clinical research using animal models can provide important insight into the mechanisms by which blast produces injury and dysfunction-but only to the degree by which such models reflect the human experience. Avoidance of trauma reminders is a hallmark of PTSD. Here, we sought to understand whether a mouse model of blast reproduces this phenomenon, in addition to blast-induced physical injuries. Drawing on well-established work from the chronic stress and Pavlovian conditioning literature, we hypothesized that even while one is anesthetized during blast exposure, environmental cues encountered in the peri-blast environment could be conditioned to evoke aversion/dysphoria and re-experiencing of traumatic stress. Using a pneumatic shock tube that recapitulates battlefield-relevant open-field blast forces, we provide direct evidence that stress is inherent to repetitive blast exposure, resulting in chronic aversive/dysphoric-like responses to previous blast-paired cues. The results in this report demonstrate that, although both single and repetitive blast exposures produce acute stress responses (weight loss, corticosterone increase), only repetitive blast exposure also results in co-occurring aversive/dysphoric-like stress responses. These results extend appreciation of the highly complex nature of repetitive blast exposure; and lend further support for the potential translational relevance of animal modeling approaches currently used by multiple laboratories aimed at elucidating the mechanisms (both molecular and behavioral) of repetitive blast exposure.

Interplay between traumatic brain injury and intimate partner violence: data driven analysis utilizing electronic health records

Background

It is estimated that a majority of intimate partner violence (IPV) victims suffer from blunt force to the head, neck and the face area. Injuries to head and neck are among the major causes for traumatic brain injury (TBI).

Methods

In this interdisciplinary study, we aimed to characterize the key associations between IPV and TBI by mining de-identified electronic health records data with more than 12 M records between 1999 to 2017 from the IBM Explorys platform. For this purpose, we formulated a data-driven analytical framework to identify significant health correlates among IPV, TBI and six control cohorts. Using this framework, we assessed the co-morbidity, shared prevalence, and synergy between pairs of conditions.

Results

Our findings suggested that health effects attributed to malnutrition, acquired thrombocytopenia, post-traumatic wound infection, local infection of wound, poisoning by cardiovascular drug, alcoholic cirrhosis, alcoholic fatty liver, and drug-induced cirrhosis were highly significant at the joint presence of IPV and TBI.

Conclusion

To develop a better understanding of how IPV is related to negative health effects, it is potentially useful to determine the interactions and relationships between symptom categories. Our results can potentially improve the accuracy and confidence of existing clinical screening techniques on determining IPV-induced TBI diagnoses.

Progress and Future Directions of the NCAA-DoD Concussion Assessment, Research, and Education (CARE) Consortium and Mind Matters Challenge at the US Service Academies

Despite the significant impact that concussion has on military service members, significant gaps remain in our understanding of the optimal diagnostic, management, and return to activity/duty criteria to mitigate the consequences of concussion. In response to these significant knowledge gaps, the US Department of Defense (DoD) and the National Collegiate Athletic Association (NCAA) partnered to form the NCAA-DoD Grand Alliance in 2014. The NCAA-DoD CARE Consortium was established with the aim of creating a national multisite research network to study the clinical and neurobiological natural history of concussion in NCAA athletes and military Service Academy cadets and midshipmen. In addition to the data collected for the larger CARE Consortium effort, the service academies have pursued military-specific lines of research relevant to operational and medical readiness associated with concussion. The purpose of this article is to describe the structure of the NCAA-DoD Grand Alliance efforts at the service academies, as well as discuss military-specific research objectives and provide an overview of progress to date. A secondary objective is to discuss the challenges associated with conducting large-scale studies in the Service Academy environment and highlight future directions for concussion research endeavors across the CARE Service Academy sites.

Preliminary study examining the mediational link between mild traumatic brain injury, acute stress, and post-traumatic stress symptoms following trauma

Background: The presence of mild traumatic brain injury (mTBI) increases post-traumatic stress disorder (PTSD) symptoms in the months following injury. However, factors that link mTBI and PTSD development are still unclear. Acute stress responses after trauma have been associated with PTSD development. mTBI may impair cognitive functions and increase anxiety immediately after trauma. Objective: This research aimed to test the possibility that mTBI increases acute stress symptoms rapidly, which in turn results in PTSD development in the subsequent months. Method: Fifty-nine patients were recruited from the emergency rooms of local hospitals. Post-mTBI, acute stress, and PTSD symptom severity were measured using the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), Acute Stress Disorder Scale (ASDS), and PTSD Checklist for DSM-5 (PCL-5), respectively. Results: Moderated mediation analysis indicated that ASDS, at 2 weeks post-trauma, mediated the relationship between RPQ scores at 2 weeks and PCL-5 scores at 3 months post-trauma, only for patients who met mTBI diagnostic criteria. Conclusions: These findings present preliminary evidence suggesting that acute stress disorder symptoms may be one of the mechanisms involved in the development of PTSD among trauma survivors who have experienced mTBI, which provides a theoretical basis for early intervention of PTSD prevention after mTBI.

Behavioral Deficits in Animal Models of Blast Traumatic Brain Injury

Blast exposure has been identified to be the most common cause for traumatic brain injury (TBI) in soldiers. Over the years, rodent models to mimic blast exposures and the behavioral outcomes observed in veterans have been developed extensively. However, blast tube design and varying experimental parameters lead to inconsistencies in the behavioral outcomes reported across research laboratories. This review aims to curate the behavioral outcomes reported in rodent models of blast TBI using shockwave tubes or open field detonations between the years 2008–2019 and highlight the important experimental parameters that affect behavioral outcome. Further, we discuss the role of various design parameters of the blast tube that can affect the nature of blast exposure experienced by the rodents. Finally, we assess the most common behavioral tests done to measure cognitive, motor, anxiety, auditory, and fear conditioning deficits in blast TBI (bTBI) and discuss the advantages and disadvantages of these tests.

Contributions of posttraumatic stress disorder (PTSD) and mild TBI (mTBI) history to suicidality in the INTRuST consortium

OBJECTIVE

Mild TBI (mTBI) and posttraumatic stress disorder (PTSD) are independent risk factors for suicidal behaviour (SB). Further, co-occurring mTBI and PTSD increase one's risk for negative health and psychiatric outcomes. However, little research has examined the role of comorbid mTBI and PTSD on suicide risk.

METHODS

The present study utilized data from the Injury and TRaUmatic STress (INTRuST) Consortium to examine the prevalence of suicidal ideation (SI) and behaviours among four groups: 1) comorbid mTBI+PTSD, 2) PTSD only, 3) mTBI only, and 4) healthy controls.

RESULTS

Prevalence of lifetime SI, current SI, and lifetime SB for individuals with mTBI+PTSD was 40%, 25%, and 19%, respectively. Prevalence of lifetime SI, current SI, and lifetime SB for individuals with PTSD only was 29%, 11%, and 11%, respectively. Prevalence of lifetime SI, current SI, and lifetime SB for individuals with mTBI only was 14%, 1%, and 2%, respectively. Group comparisons showed that individuals with mTBI alone experienced elevated rates of lifetime SI compared to healthy controls. History of mTBI did not add significantly to risk for suicidal ideation and behaviour beyond what is accounted for by PTSD.

CONCLUSION

Findings suggest that PTSD seems to be driving risk for suicidal behaviour.

Evaluation of current post-concussion protocols

The growing number of concussions and mild traumatic brain injuries (mTBI) with the lack of evidence-based treatment options is a continuous health concern. This creates problems when evaluating and providing efficacious symptom management to patients suffering from post-concussion syndrome (PCS). Numerous pharmacological and non-pharmacological agents have been utilized in an attempt to treat PCS. Some of these approaches include physical therapy, analgesics, antidepressants, and nutraceuticals. Although these treatments have had some success, there has been inconsistent outcomes, with some examples of patients' symptoms worsening. Among pharmaceutical agents, fluoxetine has been a popular choice for the symptom management of PCS. Although some patients have had symptom resolution with the use of fluoxetine, there is still a lack of conclusive data. Of the several biochemical changes that occur in a patient's brain following a concussion, an increase in reactive oxygen species (ROS) is of particular concern. In order to counteract the responses of the brain, antioxidants, such as ascorbic acid, have been utilized to reverse the damaging cellular effects. However, this may inadvertently cause an increase in ROS, rather than a reduction. Although there is a lack of consistency in exactly when each treatment was used in the post-injury interval, it is important that we analyze the strengths and weaknesses of the most commonly used agents due to the lack of a set protocol. The studies were chosen in a non-exhaustive manner and were not consistent in patients' post-injury intervals, in addition to other baseline characteristics. However, over-arching claims that some treatments may benefit more than others can be made. This review evaluates both the pharmaceutical and non-pharmaceutical protocols that are most commonly utilized in post-concussive patients for their efficacy in treatment of post-concussive syndrome (PCS).