Relationships between mild traumatic brain injury sustained in combat and post-traumatic stress disorder

Compromised Neurocircuitry in Chronic Blast-Related Mild Traumatic Brain Injury

The aim of this study was to apply recently developed automated fiber segmentation and quantification methods using diffusion tensor imaging (DTI) and DTI-based deterministic and probabilistic tractography to access local and global diffusion changes in blast-induced mild traumatic brain injury (bmTBI). Two hundred and two (202) male active US service members who reported persistent post-concussion symptoms for more than 6 months after injury were recruited. An additional forty (40) male military controls were included for comparison. DTI results were examined in relation to post-concussion and post-traumatic stress disorder (PTSD) symptoms. No significant group difference in DTI metrics was found using voxel-wise analysis. However, group comparison using tract profile analysis and tract specific analysis, as well as single subject analysis using tract profile analysis revealed the most prominent white matter microstructural injury in chronic bmTBI patients over the frontal fiber tracts, that is, the front-limbic projection fibers (cingulum bundle, uncinate fasciculus), the fronto-parieto-temporal association fibers (superior longitudinal fasciculus), and the fronto-striatal pathways (anterior thalamic radiation). Effects were noted to be sensitive to the number of previous blast exposures, with a negative association between fractional anisotropy (FA) and time since most severe blast exposure in a subset of the multiple blast-exposed group. However, these patterns were not observed in the subgroups classified using macrostructural changes (T2 white matter hyperintensities). Moreover, post-concussion symptoms and PTSD symptoms, as well as neuropsychological function were associated with low FA in the major nodes of compromised neurocircuitry. Hum Brain Mapp 38:352-369, 2017. © 2016 Wiley Periodicals, Inc.

Pathophysiological links between traumatic brain injury and post-traumatic headaches

This article reviews possible ways that traumatic brain injury (TBI) can induce migraine-type post-traumatic headaches (PTHs) in children, adults, civilians, and military personnel. Several cerebral alterations resulting from TBI can foster the development of PTH, including neuroinflammation that can activate neural systems associated with migraine. TBI can also compromise the intrinsic pain modulation system and this would increase the level of perceived pain associated with PTH. Depression and anxiety disorders, especially post-traumatic stress disorder (PTSD), are associated with TBI and these psychological conditions can directly intensify PTH. Additionally, depression and PTSD alter sleep and this will increase headache severity and foster the genesis of PTH. This article also reviews the anatomic loci of injury associated with TBI and notes the overlap between areas of injury associated with TBI and PTSD.

Post-traumatic headaches

Chronic pain, especially headache, is an exceedingly common complication of traumatic brain injury (TBI). In fact, paradoxically, the milder the TBI, the more likely one is to develop headaches. The environment of injury and the associated comorbidities can have a significant impact on the frequency and severity of headaches and commonly serve to direct management of the headaches. Trauma likely contributes to the development of headaches via alterations in neuronal signaling, inflammation, and musculoskeletal changes. The clinical picture of the patient with post-traumatic headaches is often that of a mixed headache disorder with features of tension-type headaches as well as migrainous headaches. Treatment of these headaches is thus often guided by the predominant characteristics of the headaches and can include pharmacologic and nonpharmacologic strategies. Pharmacologic therapies include both abortive and prophylactic agents with prophylaxis targeting comorbidities, primarily impaired sleep. Nonpharmacologic interventions for post-traumatic headaches include thermal and physical modalities as well as cognitive behavioral approaches. As with many postconcussive symptoms, headaches can lessen with time but in up to 25% of patients, chronic headaches are long-term residua.

Exploration of Individual and Family Factors Related to Community Reintegration in Veterans With Traumatic Brain Injury

BACKGROUND

Community reintegration (CR) poses a major problem for military veterans who have experienced a traumatic brain injury (TBI). Factors contributing to CR after TBI are poorly understood.

OBJECTIVE

To address the gap in knowledge, an ecological framework was used to explore individual and family factors related to CR.

DESIGN

Baseline data from an intervention study with 83 veterans with primarily mild to moderate TBI were analyzed. Instruments measured CR, depressive symptoms, physical health, quality of the relationship with the family member, and sociodemographics. Posttraumatic stress disorder and TBI characteristics were determined through record review.

RESULTS

Five variables that exhibited significant bivariate relationships with CR (veteran rating of quality of relationship, physical functioning, bodily pain, posttraumatic stress disorder diagnosis, and depressive symptoms) were entered into hierarchical regression analysis. In the final analysis, the five variables together accounted for 35% of the variance, but only depression was a significant predictor of CR, with more depressed veterans exhibiting lower CR.

CONCLUSIONS

Efforts to support CR of Veterans with TBI should carefully assess and target depression, a modifiable factor.

Post-traumatic headaches in civilians and military personnel: a comparative, clinical review

Post-traumatic headache (PTH) is the most frequent symptom after traumatic brain injury (TBI). We review the epidemiology and characterization of PTH in military and civilian settings. PTH appears to be more likely to develop following mild TBI (concussion) compared with moderate or severe TBI. PTH often clinically resembles primary headache disorders, usually migraine. For migraine-like PTH, individuals who had the most severe headache pain had the highest headache frequencies. Based on studies to date in both civilian and military settings, we recommend changes to the current definition of PTH. Anxiety disorders such as post-traumatic stress disorder (PTSD) are frequently associated with TBI, especially in military populations and in combat settings. PTSD can complicate treatment of PTH as a comorbid condition of post-concussion syndrome. PTH should not be treated as an isolated condition. Comorbid conditions such as PTSD and sleep disturbances also need to be treated. Double-blind placebo-controlled trials in PTH population are necessary to see whether similar phenotypes in the primary headache disorders and PTH will respond similarly to treatment. Until blinded treatment trials are completed, we suggest that, when possible, PTH be treated as one would treat the primary headache disorder(s) that the PTH most closely resembles.

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.

Postconcussional disorder and PTSD symptoms of military-related traumatic brain injury associated with compromised neurocircuitry

Traumatic brain injury (TBI) is a common combat injury, often through explosive blast, and produces heterogeneous brain changes due to various mechanisms of injury. It is unclear whether the vulnerability of white matter differs between blast and impact injury, and the consequences of microstructural changes on neuropsychological function are poorly understood in military TBI patients. Diffusion tensor imaging (DTI) techniques were used to assess the neurocircuitry in 37 U.S. service members (29 mild, 7 moderate, 1 severe; 17 blast and 20 nonblast), who sustained a TBI while deployed, compared to 14 nondeployed, military controls. High-dimensional deformable registration of MRI diffusion tensor data was followed by fiber tracking and tract-specific analysis along with region-of-interest analysis. DTI results were examined in relation to post-concussion and post-traumatic stress disorder (PTSD) symptoms. The most prominent white matter microstructural injury for both blast and nonblast patients was in the frontal fibers within the fronto-striatal (corona radiata, internal capsule) and fronto-limbic circuits (fornix, cingulum), the fronto-parieto-occipital association fibers, in brainstem fibers, and in callosal fibers. Subcortical superior-inferiorly oriented tracts were more vulnerable to blast injury than nonblast injury, while direct impact force had more detrimental effects on anterior-posteriorly oriented tracts, which tended to cause heterogeneous left and right hemispheric asymmetries of white matter connectivity. The tractography using diffusion anisotropy deficits revealed the cortico-striatal-thalamic-cerebellar-cortical (CSTCC) networks, where increased post-concussion and PTSD symptoms were associated with low fractional anisotropy in the major nodes of compromised CSTCC neurocircuitry, and the consequences on cognitive function were explored as well.

Military- and sports-related mild traumatic brain injury: clinical presentation, management, and long-term consequences

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A case-control study examining whether neurological deficits and PTSD in combat veterans are related to episodes of mild TBI

BACKGROUND

Mild traumatic brain injury (mTBI) is a common injury among military personnel serving in Iraq or Afghanistan. The impact of repeated episodes of combat mTBI is unknown.

OBJECTIVE

To evaluate relationships among mTBI, post-traumatic stress disorder (PTSD) and neurological deficits (NDs) in US veterans who served in Iraq or Afghanistan.

METHODS

This was a case-control study. From 2091 veterans screened for traumatic brain injury, the authors studied 126 who sustained mTBI with one or more episodes of loss of consciousness (LOC) in combat. Comparison groups: 21 combat veterans who had definite or possible episodes of mTBI without LOC and 21 veterans who sustained mTBI with LOC as civilians.

RESULTS

Among combat veterans with mTBI, 52% had NDs, 66% had PTSD and 50% had PTSD and an ND. Impaired olfaction was the most common ND, found in 65 veterans. The prevalence of an ND or PTSD correlated with the number of mTBI exposures with LOC. The prevalence of an ND or PTSD was >90% for more than five episodes of LOC. Severity of PTSD and impairment of olfaction increased with number of LOC episodes. The prevalence of an ND for the 34 combat veterans with one episode of LOC (4/34=11.8%) was similar to that of the 21 veterans of similar age and educational background who sustained civilian mTBI with one episode of LOC (2/21=9.5%, p-NS).

CONCLUSIONS

Impaired olfaction was the most frequently recognised ND. Repeated episodes of combat mTBI were associated with increased likelihood of PTSD and an ND. Combat setting may not increase the likelihood of an ND. Two possible connections between mTBI and PTSD are (1) that circumstances leading to combat mTBI likely involve severe psychological trauma and (2) that altered cerebral functioning following mTBI may increase the likelihood that a traumatic event results in PTSD.