A retrospective cohort study of comorbidity trajectories associated with traumatic brain injury in veterans of the Iraq and Afghanistan wars

The Impact of Non-Pain Factors on Pain Interference Among U.S. Service Members and Veterans with Symptoms of Mild Traumatic Brain Injury

U.S. Service members and Veterans (SM/V) experience elevated rates of traumatic brain injury (TBI), chronic pain, and other non-pain symptoms. However, the role of non-pain factors on pain interference levels remains unclear among SM/Vs, particularly those with a history of TBI. The primary objective of this study was to identify factors that differentiate high/low pain interference, given equivalent pain intensity among U.S. SM/V participating in the ongoing Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) national multi-center prospective longitudinal observational study. An explainable machine learning was used to identify key predictors of pain interference conditioned on equivalent pain intensity. The final sample consisted of n = 1,577 SM/Vs who were predominantly male (87%), and 83.6% had a history of mild TBI(s) (mTBI), while 16.4% were TBI negative controls. The sample was categorized according to pain interference level (Low: 19.9%, Moderate: 52.5%, and High: 27.6%). Both pain intensity scores and pain interference scores increased with the number of mTBIs (p < 0.001), and there was evidence of a dose response between the number of injuries and pain scores. Machine learning models identified fatigue and anxiety as the most important predictors of pain interference, whereas emotional control was protective. Partial dependence plots identified that marginal effects of fatigue and anxiety were associated with pain interference (p < 0.001), but the marginal effect of mTBI was not significant in models considering all variables (p > 0.05). Non-pain factors are associated with functional limitations and disability experience among SM/V with an mTBI history. The functional effects of pain may be mediated through multiple other factors. Pain is a multi-dimensional experience that may benefit most from holistic treatment approaches that target comorbidities and build supports that promote recovery.

Identifying and Predicting Subgroups of Veterans With Mild Traumatic Brain Injury Based on Distinct Configurations of Postconcussive Symptom Endorsement: A Latent Class Analysis

OBJECTIVE

To identify distinct subgroups of veterans with mild traumatic brain injury (mTBI) based on configurations of postconcussive symptom (PCS) endorsement, and to examine predictors of subgroup membership.

SETTING

Outpatient Veterans Health Administration (VHA).

PARTICIPANTS

Veterans with clinician-confirmed mTBI who completed the Neurobehavioral Symptom Inventory (NSI), determined using the Comprehensive Traumatic Brain Injury Evaluation database. Individuals who tended to overreport symptoms were excluded via an embedded symptom validity scale.

DESIGN

Retrospective cohort study leveraging national VHA clinical data from 2012 to 2020. Latent class analysis (LCA) with a split-sample cross-validation procedure was used to identify subgroups of veterans. Multinomial logistic regression was used to examine predictors of subgroup membership.

MAIN MEASURES

Latent classes identified using NSI items.

RESULTS

The study included 72 252 eligible veterans, who were primarily White (73%) and male (94%). The LCA supported 7 distinct subgroups of veterans with mTBI, characterized by diverging patterns of risk for specific PCS across vestibular (eg, dizziness), somatosensory (eg, headache), cognitive (eg, forgetfulness), and mood domains (eg, anxiety). The most prevalent subgroup was Global (20.7%), followed by Cognitive-Mood (16.3%), Headache-Cognitive-Mood (H-C-M; 16.3%), Headache-Mood (14.2%), Anxiety (13.8%), Headache-Sleep (10.3%), and Minimal (8.5%). The Global class was used as the reference class for multinomial logistic regression because it was distinguished from others based on elevated risk for PCS across all domains. Female (vs male), Black (vs White), and Hispanic veterans (vs non-Hispanic) were less likely to be members of most subgroups characterized by lesser PCS endorsement relative to the Global class (excluding Headache-Mood).

CONCLUSION

The 7 distinct groups identified in this study distill heterogenous patterns of PCS endorsement into clinically actionable phenotypes that can be used to tailor clinical management of veterans with mTBI. Findings reveal empirical support for potential racial, ethnic, and sex-based disparities in PCS among veterans, informing efforts aimed at promoting equitable recovery from mTBI in this population.

Sex Differences in Postinjury Health Profiles Among U.S. Military Personnel Following Deployment-Related Concussion

Background: Women in the U.S. military are now authorized to serve in direct combat occupations. This may increase their risk of combat injuries, such as concussion, in future conflicts. Knowledge of sex differences in health profiles after concussion is paramount for military medical planning efforts. The purpose of this study was to assess sex-related differences in health profiles among U.S. military personnel following deployment-related concussion. Materials and Methods: We conducted a retrospective study of service members who sustained a concussion during combat deployment between 2004 and 2013. Postinjury diagnoses were abstracted from outpatient encounters in electronic health records for 24 months after concussion. We used hierarchical clustering to identify clusters, termed "health profiles," and logistic regression to determine whether sex predicted membership in the health profiles. Results: The study sample included 346 women and 4536 men with deployment-related concussion. Five postinjury health profiles were identified and classified as no morbidity, back pain, tinnitus/memory loss, posttraumatic stress disorder/postconcussion syndrome, and multimorbidity. Women relative to men had higher odds of membership in the back pain (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.05-1.67) and multimorbidity profiles (OR = 1.44; 95% CI = 1.03-2.00) and lower odds than men in the tinnitus/memory loss profile (OR = 0.62; 95% CI = 0.42-0.91). Conclusions: Postinjury health profiles among U.S. service members differ by sex following deployment-related concussion, particularly with a higher burden of multimorbidity among women than men, which may require interdisciplinary care. Women also had higher odds of membership in the back pain profile and lower odds in the tinnitus/memory loss profile than men. To prepare for future military operations where women may have greater exposure to combat, continued research elucidating health-related sex differences after deployment-related concussion is imperative.

Subcortical functional connectivity and its association with walking performance following deployment related mild TBI

Introduction

The relation between traumatic brain injury (TBI), its acute and chronic symptoms, and the potential for remote neurodegenerative disease is a priority for military research. Structural and functional connectivity (FC) of the basal ganglia, involved in motor tasks such as walking, are altered in some samples of Service Members and Veterans with TBI, but any behavioral implications are unclear and could further depend on the context in which the TBI occurred.

Methods

In this study, FC from caudate and pallidum seeds was measured in Service Members and Veterans with a history of mild TBI that occurred during combat deployment, Service Members and Veterans whose mild TBI occurred outside of deployment, and Service Members and Veterans who had no lifetime history of TBI.

Results

FC patterns differed for the two contextual types of mild TBI. Service Members and Veterans with deployment-related mild TBI demonstrated increased FC between the right caudate and lateral occipital regions relative to both the non-deployment mild TBI and TBI-negative groups. When evaluating the association between FC from the caudate and gait, the non-deployment mild TBI group showed a significant positive relationship between walking time and FC with the frontal pole, implicated in navigational planning, whereas the deployment-related mild TBI group trended towards a greater negative association between walking time and FC within the occipital lobes, associated with visuo-spatial processing during navigation.

Discussion

These findings have implications for elucidating subtle motor disruption in Service Members and Veterans with deployment-related mild TBI. Possible implications for future walking performance are discussed.

Integrating unsupervised and supervised learning techniques to predict traumatic brain injury: A population-based study

This work aimed to identify pre-existing health conditions of patients with traumatic brain injury (TBI) and develop predictive models for the first TBI event and its external causes by employing a combination of unsupervised and supervised learning algorithms. We acquired up to five years of pre-injury diagnoses for 488,107 patients with TBI and 488,107 matched control patients who entered the emergency department or acute care hospitals between April 1st, 2002, and March 31st, 2020. Diagnoses were obtained from the Ontario Health Insurance Plan (OHIP) database which contains province-wide claims data by physicians in Ontario, Canada for inpatient and outpatient services. A screening process was conducted on the OHIP diagnostic codes to limit the subsequent analysis to codes that were predictive of TBI, which concluded that 314 codes were significantly associated with TBI. The Latent Dirichlet Allocation (LDA) model was applied to the diagnostic codes and generated an optimal number of 19 topics that concur with published literature but also suggest other unexplored areas. Estimated word-topic probabilities from the LDA model helped us detect pre-morbid conditions among patients with TBI by uncovering the underlying patterns of diagnoses, meanwhile estimated document-topic probabilities were utilized in variable creation as form of a dimension reduction. We created 19 topic scores for each patient in the cohort which were utilized along with socio-demographic factors for Random Forest binary classifier models. Test set performances evaluated using area under the receiver operating characteristic curve (AUC) were: TBI event (AUC = 0.85), external cause of injury: falls (AUC = 0.85), struck by/against (AUC = 0.83), cyclist collision (AUC = 0.76), motor vehicle collision (AUC = 0.83). Our analysis successfully demonstrated the feasibility of using machine learning to predict TBI due to various external causes and identified the most important factors that contribute to this prediction.

Metabolic and quality of life effects of growth hormone replacement in patients with TBI and AGHD: A pilot study

OBJECTIVE

Traumatic brain injury (TBI), a common cause of adult growth hormone deficiency (AGHD), affects 20% of Veterans returning from Iraq and Afghanistan (OEF/OIF/OND). Growth hormone replacement therapy (GHRT) improves quality of life (QoL) in AGHD but remains unexplored in this population. This pilot, observational study investigates the feasibility and efficacy of GHRT in AGHD following TBI.

DESIGN

In this 6-month study of combat Veterans with AGHD and TBI starting GHRT (N = 7), feasibility (completion rate and rhGH adherence) and efficacy (improvements in self-reported QoL) of GHRT were measured (primary outcomes). Secondary outcomes included body composition, physical and cognitive function, psychological and somatic symptoms, physical activity, IGF-1 levels and safety parameters. It was hypothesized that participants would adhere to GHRT and that QoL would significantly improve after six months.

RESULTS

Five subjects (71%) completed all study visits. All patients administered daily rhGH injections, 6 (86%) of whom consistently administered the clinically-prescribed dose. While QoL demonstrated numeric improvement, this change did not reach statistical significance (p = 0.17). Significant improvements were observed in total lean mass (p = 0.02), latissimus dorsi strength (p = 0.05), verbal learning (Trial 1, p = 0.02; Trial 5, p = 0.03), attention (p = 0.02), short-term memory (p = 0.04), and post-traumatic stress disorder (PTSD) symptoms (p = 0.03). Body weight (p = 0.02) and total fat mass (p = 0.03) increased significantly.

CONCLUSION

GHRT is a feasible and well-tolerated intervention for U.S. Veterans with TBI-related AGHD. It improved key areas impacted by AGHD and symptoms of PTSD. Larger, placebo-controlled studies testing the efficacy and safety of this intervention in this population are warranted.

Comorbidity and polypharmacy impact neurobehavioral symptoms and symptom validity failure among post-9/11 veterans with mild traumatic brain injury

Objective

The study aimed to examine the association between post-concussive comorbidity burdens [post-traumatic stress disorder (PTSD), depression, and/or headache] and central nervous system (CNS) polypharmacy (five or more concurrent medications) with reported neurobehavioral symptoms and symptom validity screening among post-9/11 veterans with a history of mild traumatic brain injury (mTBI).

Setting

Administrative medical record data from the Department of Veterans Affairs (VA) were used in the study.

Participants

Post-9/11 veterans with mTBI and at least 2 years of VA care between 2001 and 2019 who had completed the comprehensive traumatic brain injury evaluation (CTBIE) were included in the study.

Design

Retrospective cross-sectional design was used in the study.

Main measures

Neurobehavioral Symptom Inventory (NSI), International Classification of Diseases, Ninth Revision, and Clinical Modification diagnosis codes were included in the study.

Results

Of the 92,495 veterans with a history of TBI, 90% had diagnoses of at least one identified comorbidity (PTSD, depression, and/or headache) and 28% had evidence of CNS polypharmacy. Neurobehavioral symptom reporting and symptom validity failure was associated with comorbidity burden and polypharmacy after adjusting for sociodemographic characteristics. Veterans with concurrent diagnoses of PTSD, depression, and headache were more than six times more likely [Adjusted odds ratio = 6.55 (99% CI: 5.41, 7.92)]. to fail the embedded symptom validity measure (Validity-10) in the NSI.

Conclusion

TBI-related multimorbidity and CNS polypharmacy had the strongest association with neurobehavioral symptom distress, even after accounting for injury and sociodemographic characteristics. Given the regular use of the NSI in clinical and research settings, these findings emphasize the need for comprehensive neuropsychological evaluation for individuals who screen positively for potential symptom overreporting, the importance of multidisciplinary rehabilitation to restore functioning following mTBI, and the conscientious utilization of symptom validity measures in research efforts.

Clusters of conditions among US service members diagnosed with mild TBI from 2017 through 2019

Background

Many US Military Service Members (SMs) newly diagnosed with mild Traumatic Brain Injury (mTBI) may exhibit a range of symptoms and comorbidities, making for a complex patient profile that challenges clinicians and healthcare administrators. This study used clustering techniques to determine if conditions co-occurred as clusters among those newly injured with mTBI and up to one year post-injury.

Methods

We measured the co-occurrence of 41 conditions among SMs diagnosed with mTBI within the acute phase, one or three months post-mTBI diagnosis, and chronic phase, one year post-mTBI diagnosis. Conditions were identified from the literature, clinical subject matter experts, and mTBI care guidelines. The presence of conditions were based on medical encounters recorded within the military health care data system. Through a two-step approach, we identified clusters. Principal component analysis (PCA) determined the optimal number of clusters, and hierarchical cluster analyses (HCA) identified the composition of clusters. Further, we explored how the composition of these clusters changed over time.

Results

Of the 42,018 SMs with mTBI, 23,478 (55.9%) had at least one condition of interest one-month post-injury, 26,831 (63.9%) three months post-injury, and 29,860 (71.1%) one year post injury. Across these three periods, six clusters were identified. One cluster included vision, cognitive, ear, and sleep disorders that occurred one month, three months, and one year post-injury. Another subgroup included psychological conditions such as anxiety, depression, PTSD, and other emotional symptoms that co-occurred in the acute and chronic phases post-injury. Nausea and vomiting symptoms clustered with cervicogenic symptoms one month post-injury, but later shifted to other clusters. Vestibular disorders clustered with sleep disorders and headache disorders one-month post-injury and included numbness and neuropathic pain one year post-injury. Substance abuse symptoms, alcohol disorders, and suicidal attempt clustered one year post-injury in a fifth cluster. Speech disorders co-occurred with headache disorders one month and one year post-injury to form a sixth cluster.

Conclusion

PCA and HCA identified six distinct subgroups among newly diagnosed mTBI patients during the acute and chronic phases post-injury. These subgroups may help clinicians better understand the complex profile of SMs newly diagnosed with mTBI.

Understanding multimorbidity trajectories in Scotland using sequence analysis

Understanding how multiple conditions develop over time is of growing interest, but there is currently limited methodological development on the topic, especially in understanding how multimorbidity (the co-existence of at least two chronic conditions) develops longitudinally and in which order diseases occur. We aim to describe how a longitudinal method, sequence analysis, can be used to understand the sequencing of common chronic diseases that lead to multimorbidity and the socio-demographic factors and health outcomes associated with typical disease trajectories. We use the Scottish Longitudinal Study (SLS) linking the Scottish census 2001 to disease registries, hospitalisation and mortality records. SLS participants aged 40–74 years at baseline were followed over a 10-year period (2001–2011) for the onset of three commonly occurring diseases: diabetes, cardiovascular disease (CVD), and cancer. We focused on participants who transitioned to at least two of these conditions over the follow-up period (N = 6300). We use sequence analysis with optimal matching and hierarchical cluster analysis to understand the process of disease sequencing and to distinguish typical multimorbidity trajectories. Socio-demographic differences between specific disease trajectories were evaluated using multinomial logistic regression. Poisson and Cox regressions were used to assess differences in hospitalisation and mortality outcomes between typical trajectories. Individuals who transitioned to multimorbidity over 10 years were more likely to be older and living in more deprived areas than the rest of the population. We found seven typical trajectories: later fast transition to multimorbidity, CVD start with slow transition to multimorbidity, cancer start with slow transition to multimorbidity, diabetes start with slow transition to multimorbidity, fast transition to both diabetes and CVD, fast transition to multimorbidity and death, fast transition to both cancer and CVD. Those who quickly transitioned to multimorbidity and death were the most vulnerable, typically older, less educated, and more likely to live in more deprived areas. They also experienced higher number of hospitalisations and overnight stays while still alive. Sequence analysis can strengthen our understanding of typical disease trajectories when considering a few key diseases. This may have implications for more active clinical review of patients beginning quick transition trajectories.

Photosensitivity Is Associated with Chronic Pain following Traumatic Brain Injury

Individuals with a history of traumatic brain injury (TBI) report increased rates of chronic pain. Photosensitivity is also a common chronic symptom following TBI and is prevalent among other types of chronic pain. The aim of this study was to better understand the relationship between chronic pain, pain-related disability, and photosensitivity in a TBI population. We quantified participants' visual photosensitivity thresholds (VPT) using an Ocular Photosensitivity Analyzer and measured pressure-pain sensitivity using pressure algometry. Participants also completed a battery of self-report measures related to chronic pain, TBI history, and mental health. A total of 395 participants completed testing, with 233 reporting a history of TBI. The TBI group was divided into 120 symptomatic TBI participants (s-TBI), and 113 asymptomatic TBI participants (a-TBI) based on their Neurobehavioral Symptom Inventory (NSI) scores. Participants in the s-TBI group scored significantly higher on self-reported chronic pain measures compared with a-TBI and no-TBI participants, including the Symptom Impact Questionnaire Revised (SIQR; p < 0.001) and the Michigan Body Map (MBM; p < 0.001). Despite differences in chronic pain complaints, groups displayed similar pressure-pain thresholds (p = 0.270). Additionally, s-TBI participants were more sensitive to light (lower VPT, p < 0.001), and VPT was correlated with SIQR scores across all participants (R = -0.452, p < 0.001). These data demonstrate that photosensitivity is associated with self-reported chronic pain and disability in individuals with chronic TBI symptomatology. Photosensitivity could therefore serve as a simple, more highly quantitative marker of high-impact chronic pain after TBI.

Patients' and caregivers' perspectives on healthcare navigation in Central Indiana, USA after brain injury

Little research has documented the experiences of patients with traumatic brain injury (TBI) and their caregivers in navigating health systems for TBI care. In this qualitative study, we conducted semi-structured interviews with 62 participants (34 patients with moderate or severe TBI and 28 caregivers) from Central Indiana. Data were collected from January to September 2016 and analysed using a constructivist grounded theory approach. Participants discussed three significant challenges about navigating health services for TBI care: lack of support for care navigation, financial barriers, and communication barriers. Participants described how navigating outpatient healthcare services for TBI remains complex and emphasised the need for ongoing care navigation support throughout the care continuum. They detailed the long-term financial burden of TBI including high treatment costs, limited insurance coverage, and the emotional toll that financial stress has on their ability to navigate healthcare services for ongoing TBI-related needs. They also discussed how ineffective patient-provider communication and lack of reliable, timely and comprehensive health information about TBI limited their engagement in and navigation of TBI health services. Findings suggest that persons with TBI and their caregivers need ongoing support to manage the long-term impacts of TBI. Efforts to provide care coordination and navigation to patients with TBI and their families are urgently needed to facilitate greater access to care, effective healthcare navigation and improved health outcomes.

Complex pain phenotypes: Suicidal ideation and attempt through latent multimorbidity

Background

Given the relatively high rates of suicidal ideation and attempt among people with chronic pain, there is a need to understand the underlying factors to target suicide prevention efforts. To date, no study has examined the association between pain phenotypes and suicide related behaviors among those with mild traumatic brain injuries.

Objective

To determine if pain phenotypes were independently associated with suicidal ideation / attempt or if comorbidities within the pain phenotypes account for the association between pain phenotypes and suicide related behaviors.

Methods

This is a longitudinal retrospective cohort study of suicide ideation/attempts among pain phenotypes previously derived using general mixture latent variable models of the joint distribution of repeated measures of pain scores and pain medications/treatment. We used national VA inpatient, outpatient, and pharmacy data files for Post-9/11 Veterans with mild traumatic injury who entered VA care between fiscal years (FY) 2007 and 2009. We considered a counterfactual causal modeling framework to assess the extent that the pain phenotypes during years 1–5 of VA care were predictive of suicide ideation/attempt during years 6–8 of VA care conditioned on covariates being balanced between pain phenotypes.

Results

Without adjustment, pain phenotypes were significant predictors of suicide related behaviors. When we used propensity scores to balance the comorbidities present in the pain phenotypes, the pain phenotypes were no longer significantly associated with suicide related behaviors.

Conclusion

These findings suggest that suicide ideation/attempt is associated with pain trajectories primarily through latent multimorbidity. Therefore, it is critical to identify and manage comorbidities (e.g., depression, post-traumatic stress disorder) to prevent tragic outcomes associated with suicide related behaviors throughout the course of chronic pain and mild traumatic brain injury management.

Low resilience following traumatic brain injury is strongly associated with poor neurobehavioral functioning in U.S. military service members and veterans

OBJECTIVE

The purpose of this study was to examine the relationship between resilience and self-reported neurobehavioral functioning following traumatic brain injury (TBI) in U.S. military service members and veterans (SMVs). A secondary objective was to examine the interaction between resilience and posttraumatic stress disorder (PTSD) on neurobehavioral functioning.

METHOD

Participants included 795 SMVs classified into four groups: Uncomplicated Mild TBI (MTBI; n=300); Complicated Mild, Moderate, Severe, or Penetrating TBI (STBI, n 162); Injured Controls (IC, n=185); and Non-injured Controls (NIC, n=148). Two independent cohorts were evaluated - those assessed within 1-year of injury and those assessed 10-years post-injury. SMVs completed self-report measures including the PTSD Checklist-Civilian version, Neurobehavioral Symptom Inventory, and TBI-Quality of Life.

RESULTS

Results showed that (1) lower resilience was strongly associated with poorer neurobehavioral functioning across all groups at 1-year and 10-years post-injury, and (2) PTSD and resilience had a robust influence on neurobehavioral functioning at both time periods post-injury, such that SMVs with PTSD and low resilience displayed the poorest neurobehavioral functioning.

CONCLUSION

Results suggest that regardless of injury group and time since injury, resilience and PTSD strongly influence neurobehavioral functioning following TBI among SMVs. Future research evaluating interventions designed to enhance resilience in this population is indicated.

Studying trajectories of multimorbidity: a systematic scoping review of longitudinal approaches and evidence

OBJECTIVES

Multimorbidity-the co-occurrence of at least two chronic diseases in an individual-is an important public health challenge in ageing societies. The vast majority of multimorbidity research takes a cross-sectional approach, but longitudinal approaches to understanding multimorbidity are an emerging research area, being encouraged by multiple funders. To support development in this research area, the aim of this study is to scope the methodological approaches and substantive findings of studies that have investigated longitudinal multimorbidity trajectories.

DESIGN

We conducted a systematic search for relevant studies in four online databases (Medline, Scopus, Web of Science and Embase) in May 2020 using predefined search terms and inclusion and exclusion criteria. The search was complemented by searching reference lists of relevant papers. From the selected studies, we systematically extracted data on study methodology and findings and summarised them in a narrative synthesis.

RESULTS

We identified 35 studies investigating multimorbidity longitudinally, all published in the last decade, and predominantly in high-income countries from the Global North. Longitudinal approaches employed included constructing change variables, multilevel regression analysis (eg, growth curve modelling), longitudinal group-based methodologies (eg, latent class modelling), analysing disease transitions and visualisation techniques. Commonly identified risk factors for multimorbidity onset and progression were older age, higher socioeconomic and area-level deprivation, overweight and poorer health behaviours.

CONCLUSION

The nascent research area employs a diverse range of longitudinal approaches that characterise accumulation and disease combinations and to a lesser extent disease sequencing and progression. Gaps include understanding the long-term, life course determinants of different multimorbidity trajectories, and doing so across diverse populations, including those from low-income and middle-income countries. This can provide a detailed picture of morbidity development, with important implications from a clinical and intervention perspective.

Longitudinal mental health outcomes of combat-injured service members

BACKGROUND

The relationship between traumatic injury and subsequent mental health diagnoses is not well understood and may have significant implications for patient screening and clinical intervention. We sought to determine the adjusted association between traumatic injury and the subsequent development of post-traumatic stress disorder (PTSD), depression, and anxiety.

METHODS

Using Department of Defense and Veterans Affairs datasets between February 2002 and June 2016, we conducted a retrospective cohort study of 7,787 combat-injured United States service members matched 1:1 to combat-deployed, uninjured service members. The primary exposure was combat injury versus no combat injury. Outcomes were diagnoses of PTSD, depression, and anxiety, defined by International Classification of Diseases 9th and 10th Revision Clinical Modification codes.

RESULTS

Compared to noninjured service members, injured service members had higher observed incidence rates per 100 person-years for PTSD (17.1 vs. 5.8), depression (10.4 vs. 5.7), and anxiety (9.1 vs. 4.9). After adjustment, combat-injured patients were at increased risk of development of PTSD (HR 2.92, 95%CI 2.68-3.17), depression (HR 1.47, 95%CI 1.36-1.58), and anxiety (HR 1.34, 95%CI 1.24-1.45).

CONCLUSIONS

Traumatic injury is associated with subsequent development of PTSD, depression, and anxiety. These findings highlight the importance of increased screening, prevention, and intervention in patients with exposure to physical trauma.

Potential Health and Performance Effects of High-Level and Low-Level Blast: A Scoping Review of Two Decades of Research

Although blast exposure has been recognized as a significant source of morbidity and mortality in military populations, our understanding of the effects of blast exposure, particularly low-level blast (LLB) exposure, on health outcomes remains limited. This scoping review provides a comprehensive, accessible review of the peer-reviewed literature that has been published on blast exposure over the past two decades, with specific emphasis on LLB. We conducted a comprehensive scoping review of the scientific literature published between January 2000 and 2019 pertaining to the effects of blast injury and/or exposure on human and animal health. A three-level review process with specific inclusion and exclusion criteria was used. A full-text review of all articles pertaining to LLB exposure was conducted and relevant study characteristics were extracted. The research team identified 3,215 blast-relevant articles, approximately half of which (55.4%) studied live humans, 16% studied animals, and the remainder were non-subjects research (e.g., literature reviews). Nearly all (99.49%) of the included studies were conducted by experts in medicine or epidemiology; approximately half of these articles were categorized into more than one medical specialty. Among the 51 articles identified as pertaining to LLB specifically, 45.1% were conducted on animals and 39.2% focused on human subjects. Animal studies of LLB predominately used shock tubes to induce various blast exposures in rats, assessed a variety of outcomes, and clearly demonstrated that LLB exposure is associated with brain injury. In contrast, the majority of LLB studies on humans were conducted among military and law enforcement personnel in training environments and had remarkable variability in the exposures and outcomes assessed. While findings suggest that there is the potential for LLB to harm human populations, findings are mixed and more research is needed. Although it is clear that more research is needed on this rapidly growing topic, this review highlights the detrimental effects of LLB on the health of both animals and humans. Future research would benefit from multidisciplinary collaboration, larger sample sizes, and standardization of terminology, exposures, and outcomes.

Understanding Traumatic Brain Injury in Females: A State-of-the-Art Summary and Future Directions

In this report, we identify existing issues and challenges related to research on traumatic brain injury (TBI) in females and provide future directions for research. In 2017, the National Institutes of Health, in partnership with the Center for Neuroscience and Regenerative Medicine and the Defense and Veterans Brain Injury Center, hosted a workshop that focused on the unique challenges facing researchers, clinicians, patients, and other stakeholders regarding TBI in women. The goal of this "Understanding TBI in Women" workshop was to bring together researchers and clinicians to identify knowledge gaps, best practices, and target populations in research on females and/or sex differences within the field of TBI. The workshop, and the current literature, clearly highlighted that females have been underrepresented in TBI studies and clinical trials and have often been excluded (or ovariectomized) in preclinical studies. Such an absence in research on females has led to an incomplete, and perhaps inaccurate, understanding of TBI in females. The presentations and discussions centered on the existing knowledge regarding sex differences in TBI research and how these differences could be incorporated in preclinical and clinical efforts going forward. Now, a little over 2 years later, we summarize the issues and state of the science that emerged from the "Understanding TBI in Women" workshop while incorporating updates where they exist. Overall, despite some progress, there remains an abundance of research focused on males and relatively little explicitly on females.

Pain anxiety and rehabilitation outcomes after acquired brain injury

Purpose: The purpose of this study was to examine pain anxiety after acquired brain injury (ABI) and its relationship to rehabilitation outcomes.Materials and Method: Participants consisted of 89 adults with an ABI participating in outpatient rehabilitation therapy. They completed a battery of neuropsychological tests at baseline along with surveys of mood, health-related self-efficacy, and pain anxiety. Separately, occupational therapists assessed basic and instrumental activities of daily living (ADLs) as well as therapy engagement across treatment after the sixth session.Results: Individuals who reported high pain anxiety had fewer years of formal education, lower self-efficacy, and more emotional distress than those with low pain anxiety. Although Blacks were about half (56%) of the study sample, they comprised the majority (73.1%) of individuals in the high pain anxiety group. Pain anxiety was negatively related to therapy engagement. Moderation analysis using linear regression indicated that pain anxiety moderated the influence of self-efficacy on basic ADLs.Conclusions: Pain anxiety, particularly when high, is negatively associated with rehabilitation outcomes for individuals with ABI. Among those with high pain anxiety, health-related self-efficacy is an important resilience characteristic to improve functional outcomes. In rehabilitation therapy, pain anxiety provides a novel intervention target to enhance ABI recovery.

Sex-Specific Differences in Rodents Following a Single Primary Blast Exposure: Focus on the Monoamine and Galanin Systems

Most blast-induced traumatic brain injuries (bTBI) are mild in severity and culpable for the lingering and persistent neuropsychological complaints in affected individuals. There is evidence that the prevalence of symptoms post-exposure may be sex-specific. Our laboratory has focused on changes in the monoamine and the neuropeptide, galanin, systems in male rodents following primary bTBI. In this study, we aimed to replicate these findings in female rodents. Brainstem sections from the locus coeruleus (LC) and dorsal raphe nuclei (DRN) were processed for in situ hybridisation at 1 and 7 days post-bTBI. We investigated changes in the transcripts for tyrosine hydroxylase (TH), tryptophan hydroxylase two (TPH2) and galanin. Like in males, we found a transient increase in TH transcript levels bilaterally in the female LC. Changes in TPH2 mRNA were more pronounced and extensive in the DRN of females compared to males. Galanin mRNA was increased bilaterally in the LC and DRN, although this increase was not apparent until day 7 in the LC. Serum analysis revealed an increase in corticosterone, but only in exposed females. These changes occurred without any visible signs of white matter injury, cell death, or blood–brain barrier breakdown. Taken together, in the apparent absence of visible structural damage to the brain, the monoamine and galanin systems, two key players in emotional regulation, are activated deferentially in males and females following primary blast exposure. These similarities and differences should be considered when developing and evaluating diagnostic and therapeutic interventions for bTBI.

Behavioral responses following repeated bilateral frontal region closed head impacts and fear conditioning in male and female mice

The frontal lobes are among the most vulnerable sites in traumatic brain injuries. In the current study, a balanced 2 × 2 × 2 design (n = 18 mice/group), female and male C57Bl/6J mice received repeated bilateral frontal concussive brain injury (frCBI) and underwent fear conditioning (FC) to assess how injured mice respond to adverse conditions. Shocks received during FC impacted behavior on all subsequent tests except the tail suspension test. FC resulted in more freezing behavior in all mice that received foot shocks when evaluated in subsequent context and cue tests and induced hypoactivity in the open field (OF) and elevated zero maze (EZM). Mice that sustained frCBI learned the FC association between tone and shock. Injured mice froze less than sham controls during context and cue tests, which could indicate memory impairment, but could also suggest that frCBI resulted in hyperactivity that overrode the rodent's natural freezing response to threat, as injured mice were also more active in the OF and EZM. There were notable sex differences, where female mice exhibited more freezing behavior than male mice during FC context and cue tests. The findings suggest frCBI impaired, but did not eliminate, FC retention and resulted in an overall increase in general activity. The injury was characterized pathologically by increased inflammation (CD11b staining) in cortical regions underlying the injury site and in the optic tracts. The performance of male and female mice after injury suggested the complexity of possible sex differences for neuropsychiatric symptoms.

Sex as a Biological Variable in Preclinical Modeling of Blast-Related Traumatic Brain Injury

Approaches to furthering our understanding of the bioeffects, behavioral changes, and treatment options following exposure to blast are a worldwide priority. Of particular need is a more concerted effort to employ animal models to determine possible sex differences, which have been reported in the clinical literature. In this review, clinical and preclinical reports concerning blast injury effects are summarized in relation to sex as a biological variable (SABV). The review outlines approaches that explore the pertinent role of sex chromosomes and gonadal steroids for delineating sex as a biological independent variable. Next, underlying biological factors that need exploration for blast effects in light of SABV are outlined, including pituitary, autonomic, vascular, and inflammation factors that all have evidence as having important SABV relevance. A major second consideration for the study of SABV and preclinical blast effects is the notable lack of consistent model design—a wide range of devices have been employed with questionable relevance to real-life scenarios—as well as poor standardization for reporting of blast parameters. Hence, the review also provides current views regarding optimal design of shock tubes for approaching the problem of primary blast effects and sex differences and outlines a plan for the regularization of reporting. Standardization and clear description of blast parameters will provide greater comparability across models, as well as unify consensus for important sex difference bioeffects.

Providing Care for Comorbid Mental Health Conditions in the Polytrauma System of Care

OBJECTIVE

To summarize challenges and best practices relevant to providing care for mental health comorbidities in veterans and service members (V/SM) treated in the Polytrauma System of Care (PSC) and to review themes that emerged during a May 2017 meeting of rehabilitation professionals on this topic. Management of comorbid mental health conditions remains a critical issue within the PSC, given the high rate of these comorbidities and the impact of mental health conditions on treatment planning and outcomes.

DESIGN

To identify the challenges of concomitantly treating TBI-related symptoms and mental health comorbidities in V/SM treated within the PSC, describe specialty programs within the Veterans Health Administration designed to treat these comorbid conditions, and report on the themes and recommendations identified by rehabilitation professionals at the 2017 meeting.

CONCLUSION

To further develop mental health treatment within the PSC, the following recommendations were made: (1) continued support for family members as critical members of the rehabilitation team; (2) adding measures and mechanisms to monitor mental health within the PSC; and (3) exploration of modern technologies to enhance care of existing polytrauma clients and to better prepare to serve clients with all types of acquired brain injury.

Self-reported Participation Restrictions Among Male and Female Veterans With Traumatic Brain Injury in Veterans Health Administration Outpatient Polytrauma Programs

OBJECTIVES

To identify areas of most restricted self-reported participation among veterans with traumatic brain injury (TBI), explore associations among participation restriction and clinical characteristics, and examine differences in participation restrictions by sex.

DESIGN

Retrospective cross-sectional design.

SETTING

National VA Polytrauma System of Care outpatient settings.

PARTICIPANTS

Veterans with a confirmed TBI event (N=6065).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

Mayo-Portland Participation Index (M2PI), a 5-point Likert-type scale with 8 items. Total score was converted to standardized T score for analysis.

RESULTS

The sample consisted of 5679 male and 386 female veterans with ≥1 clinically confirmed TBI events (69% white; 74% with blast exposure). The M2PI items with greatest perceived restrictions were social contact, leisure, and initiation. There were no significant differences between men and women on M2PI standardized T scores. Wilcoxon rank-sum analyses showed significant differences by sex on 4 items: leisure, residence, employment, and financial management (all P<.01). In multinomial logistic regression on each item controlling for demographics, injury characteristics, and comorbidities, female veterans had significantly greater relative risk for part-time work and unemployment on the employment item and significantly less risk for impairment on the residence and financial management item.

CONCLUSIONS

There was no significant difference between men and women. Veterans on M2PI standardized T scores, which masks differences in response patterns to individual items. Clinical teams should be encouraged to discuss perceived restrictions with patients and target these areas in treatment planning. Future work is needed to investigate the psychometric properties of the M2PI by biological sex.

Concordance between current American Academy of Sleep Medicine and Centers for Medicare and Medicare scoring criteria for obstructive sleep apnea in hospitalized persons with traumatic brain injury: a VA TBI Model System study

STUDY OBJECTIVES

The objective of this study was to compare obstructive sleep apnea (OSA), demographic, and traumatic brain injury (TBI) characteristics across the American Academy of Sleep Medicine (AASM) and Centers for Medicare and Medicare (CMS) scoring rules in moderate to severe TBI undergoing inpatient neurorehabilitation.

METHODS

This is a secondary analysis from a prospective clinical trial of sleep apnea at 6 TBI Model System study sites (n = 248). Scoring was completed by a centralized center using both the AASM and CMS criteria for OSA. Hospitalization and injury characteristics were abstracted from the medical record, and demographics were obtained by interview by trained research assistants using TBI Model System standard procedures.

RESULTS

OSA was prevalent using the AASM (66%) and CMS (41.5%) criteria with moderate to strong agreement (weighted κ = 0.64; 95% confidence interval = 0.58-0.70). Significant differences were observed for participants meeting AASM and CMS criteria (concordant group) compared with those meeting criteria for AASM but not CMS (discordant group). At an apnea-hypopnea index ≥ 5 events/h, the discordant group (n = 61) had lower Emergency Department Glasgow Coma Scale Scores consistent with greater injury severity (median, 5 vs 13; P = .0050), younger age (median, 38 vs 58; P < .0001), and lower body mass index (median, 22.1 vs 24.8; P = .0007) compared with the concordant group (n = 103). At an apnea-hypopnea index ≥ 15 events/h, female sex but no other differences were noted, possibly because of the smaller sample size.

CONCLUSIONS

The underestimation of sleep apnea using CMS criteria is consistent with prior literature; however, this is the first study to report the impact of the criteria in persons with moderate to severe TBI during a critical stage of neural recovery. Management of comorbidities in TBI has become an increasing focus for optimizing TBI outcomes. Given the chronic morbidity after moderate to severe TBI, the impact of CMS policy for OSA diagnosis for persons with chronic disability and young age are considerable.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Comparison of Sleep Apnea Assessment Strategies to Maximize TBI Rehabilitation Participation and Outcome; Identifier: NCT03033901.

Traumatic brain injury among female veterans: a review of sex differences in military neurosurgery

The impact of traumatic brain injury (TBI) has been demonstrated in various studies with respect to prevalence, morbidity, and mortality data. Many of the patients burdened with long-term sequelae of TBI are veterans. Although fewer in number, female veterans with TBI have been suggested to suffer from unique physical, mental, and social challenges. However, there remains a significant knowledge gap in the sex differences in TBI. Increased female representation in the military heralds an increased risk of TBI for female soldiers, and medical professionals must be prepared to address the unique health challenges in the face of changing demographics among the veteran TBI population. In this review, the authors aimed to present the current understanding of sex differences in TBI in the veteran population and suggest directions for future investigations.

Validity of early-onset dementia diagnoses in VA electronic medical record administrative data

OBJECTIVE

To determine the validity of diagnoses indicative of early-onset dementia (EOD) obtained from an algorithm using administrative data, we examined Veterans Health Administration (VHA) electronic medical records (EMRs).

METHOD

A previously used method of identifying cases of dementia using administrative data was applied to a random sample of 176 cases of Post-9/11 deployed veterans under 65 years of age. Retrospective, cross-sectional examination of EMRs was conducted, using a combination of administrative data, chart abstraction, and review/consensus by board-certified neuropsychologists.

RESULTS

Approximately 73% of EOD diagnoses identified using existing algorithms were identified as false positives in the overall sample. This increased to approximately 76% among those with mental health conditions and approximately 85% among those with mild traumatic brain injury (TBI; i.e. concussion). Factors related to improved diagnostic accuracy included more severe TBI, diagnosing clinician type, presence of neuroimaging data, absence of a comorbid mental health condition diagnosis, and older age at time of diagnosis.

CONCLUSIONS

A previously used algorithm for detecting dementia using VHA administrative data was not supported for use in the younger adult samples and resulted in an unacceptably high number of false positives. Based on these findings, there is concern for possible misclassification in population studies using similar algorithms to identify rates of EOD among veterans. Further, we provide suggestions to develop an enhanced algorithm for more accurate dementia surveillance among younger populations.

Amyotrophic Lateral Sclerosis Among Veterans Deployed in Support of Post-9/11 U.S. Conflicts

INTRODUCTION

Amyotrophic lateral sclerosis (ALS) is a recognized military service-connected condition. Prior prevalence studies of ALS among U.S. war Veterans were not able to address concerns related to neurodegenerative sequelae of traumatic brain injury (TBI) and disregarded risk heterogeneity from occupational categories within service branches.

MATERIALS AND METHODS

We identified the prevalence of definite and possible ALS and cumulative incidence of definite ALS among Post-9/11 U.S. Veterans deployed in support of Post-9/11 conflicts (mean age 36.3) who received care in the Veterans Health Administration during fiscal years 2002-2015. Using a case-control study design, we also evaluated the association of TBI and major military occupation groups with ALS adjusting for demographics and comorbidities.

RESULTS

The prevalence of ALS was 19.7 per 100,000 over 14 years. Both prevalence and cumulative incidence of definite ALS were significantly higher among Air Force personnel compared to other service branches and among tactical operation officers and health care workers compared to general and administrative officers. Neither TBI nor younger age (<45 years) was associated with ALS. Depression, cardiac disease, cerebrovascular disease, high blood pressure, and obstructive sleep apnea were clinical comorbidities significantly associated with ALS in this population of Veterans.

CONCLUSION

This study among a cohort of relatively young Veterans showed a high ALS prevalence, suggesting an early onset of ALS among deployed military service members. The higher prevalence among some military specific occupations highlights the need to determine which occupational exposures specific to these occupations (particularly, Air Force personnel, tactical operations officers, and health care workers) might be associated with early onset ALS.

Gender Differences in Outcomes after Traumatic Brain Injury among Service Members and Veterans

This scoping study describes the range of outcomes in traumatic brain injury (TBI) studies of military service members and veterans addressing gender differences. A secondary purpose is to identify differences in outcomes between male and female participants in such studies. We searched PubMed, CiNAHL, and PsycInfo databases for relevant articles. Two reviewers independently screened results. Of 822 unique titles and abstracts screened for eligibility, 55 full articles were reviewed, with 29 studies meeting full inclusion criteria. Twenty of the 29 included studies used retrospective designs and all but two used data collected from Veterans Affairs or Department of Defense health care settings. TBI was diagnosed by self-report, screening, and evaluation procedures, and medical record documentation. Ten different outcome categories were identified among the included studies. In general, female service members and veterans have not been well represented in TBI outcomes research. Evidence suggests that female veterans with mild TBI (mTBI) report more neurobehavioral symptoms and use more outpatient services than male veterans. Studies also indicate that female veterans with TBI are more frequently diagnosed with depression. Additional research is essential to support precision treatment recommendations for female veterans with TBI, as women represent a growing proportion of the patients served by the Veterans Health Administration. LEVEL OF EVIDENCE: IV.

Deployment, suicide, and overdose among comorbidity phenotypes following mild traumatic brain injury: A retrospective cohort study from the Chronic Effects of Neurotrauma Consortium

Mild traumatic brain injury in the Veteran population is frequently comorbid with pain, post-traumatic stress disorder, and/or depression. However, not everyone exposed to mild traumatic brain injury experiences these comorbidities and it is unclear what factors contribute to this variability. The objective of this study was to identify comorbidity phenotypes among Post-9/11 deployed Veterans with no or mild traumatic brain injury and examine the association of comorbidity phenotypes with adverse outcomes. We found that Veterans with mild traumatic brain injury (n = 93,003) and no brain injury (n = 434,378) were mean age of 32.0 (SD 9.21) on entering Department of Veterans Health Administration care, were predominantly Caucasian non-Hispanic (64.69%), and served in the Army (61.31%). Latent class analysis revealed five phenotypes in each subcohort; Moderately Healthy and Mental Health phenotypes were common to both. The Healthy phenotype was found only in no brain injury. Unique phenotypes in mild traumatic brain injury included Moderately Healthy+Decline, Polytrauma, and Polytrauma+Improvement. There was substantial variation in adverse outcomes. The Polytrauma+Improvement phenotype had the lowest likelihood of adverse outcomes. There were no differences between Moderately Healthy+Decline and Polytrauma phenotypes. Phenotypes of comorbidity vary significantly by traumatic brain injury status including divergence in phenotypes (and outcomes) over time in the mild traumatic brain injury subcohort. Understanding risk factors for the divergence between Polytrauma vs. Polytrauma+Improvement and Moderately Healthy vs. Moderately Healthy+Decline, will improve our ability to proactively mitigate risk, better understand the early patterns of comorbidity that are associated with neurodegenerative sequelae following mild traumatic brain injury, and plan more patient-centered care.

Sleep and timing of death by suicide among U.S. Veterans 2006–2015: analysis of the American Time Use Survey and the National Violent Death Reporting System

Study Objectives

Suicide is a top public health priority, and U.S. Veterans are recognized to be at particularly elevated risk. Sleep disturbances are an independent risk factor for suicide; recent empirical data suggest that nocturnal wakefulness may be a key mechanism underlying this association. Given higher rates of sleep disturbances among U.S. Veterans compared with civilians, we examined associations between nocturnal wakefulness and timing of death by suicide in U.S. Veterans and civilians to determine whether temporal suicide patterns differed.

Methods

The American Time Use Survey and the National Violent Death Reporting System were analyzed (2006–2015) to determine whether sleep and temporal suicide patterns differed between age-stratified groups (18–39, 40–64, and ≥65) of U.S. Veterans and civilians. Observed temporal suicide patterns were reported and standardized incidence ratios (SIRs) calculated to compare the percentage of suicides observed with those expected, given the proportion of the population awake, across clock hours.

Results

The raw proportion of Veteran suicides peaks between the hours of 1000–1200; however, the peak prevalence of suicide after accounting for the population awake is between 0000 and 0300 hr (p < .00001, ϕ = .88). The highest SIR was at midnight; U.S. Veterans were eight times more likely to die by suicide than expected given the population awake (SIR = 8.17; 95% CI = 7.45–8.94).

Conclusions

Nocturnal wakefulness is associated with increased risk for suicide in U.S. Veterans. Overall patterns of observed suicides by clock hour were similar between U.S. Veterans and civilians. However, Veteran-specific SIRs suggest differences in magnitude of risk by clock hour across age groups. Future research examining female and Post-9/11 U.S. Veterans is warranted.

Recommendations for the Evaluation of Cross-System Care Coordination from the VA State-of-the-art Working Group on VA/Non-VA Care

In response to widespread concerns regarding Veterans' access to VA care, Congress enacted the Veterans Access, Choice and Accountability Act of 2014, which required VA to establish the Veterans Choice Program (VCP). Since the inception of VCP, more than two million Veterans have received care from community providers, representing approximately 25% of Veterans enrolled in VA care. However, expanded access to non-VA care has created challenges in care coordination between VA and community health systems. In March 2018, the VA Health Services Research & Development Service hosted a VA State of the Art conference (SOTA) focused on care coordination. The SOTA convened VA researchers, program directors, clinicians, and policy makers to identify knowledge gaps regarding care coordination within the VA and between VA and community systems of care. This article provides a summary and synthesis of relevant literature and provides recommendations generated from the SOTA about how to evaluate cross-system care coordination. Care coordination is typically evaluated using health outcomes including hospital readmissions and death; however, in cross-system evaluations of care coordination, measures such as access, cost, Veteran/patient and provider satisfaction (including with cross-system communication), comparable quality metrics, context (urban vs. rural), and patient complexity (medical and mental health conditions) need to be included to fully evaluate care coordination effectiveness. Future research should examine the role of multiple individuals coordinating VA and non-VA care, and how these coordinators work together to optimize coordination.

An experimental study on the early diagnosis of traumatic brain injury in rabbits based on a noncontact and portable system

Closed cerebral hemorrhage (CCH) is a common symptom in traumatic brain injury (TBI) patients who suffer intracranial hemorrhage with the dura mater remaining intact. The diagnosis of CCH patients prior to hospitalization and in the early stage of the disease can help patients get earlier treatments that improve outcomes. In this study, a noncontact, portable system for early TBI-induced CCH detection was constructed that measures the magnetic induction phase shift (MIPS), which is associated with the mean brain conductivity caused by the ratio between the liquid (blood/CSF and the intracranial tissues) change. To evaluate the performance of this system, a rabbit CCH model with two severity levels was established based on the horizontal biological impactor BIM-II, whose feasibility was verified by computed tomography images of three sections and three serial slices. There were two groups involved in the experiments (group 1 with 10 TBI rabbits were simulated by hammer hit with air pressure of 600 kPa by BIM-II and group 2 with 10 TBI rabbits were simulated with 650 kPa). The MIPS values of the two groups were obtained within 30 min before and after injury. In group 1, the MIPS values showed a constant downward trend with a minimum value of −11.17 ± 2.91° at the 30th min after 600 kPa impact by BIM-II. After the 650 kPa impact, the MIPS values in group 2 showed a constant downward trend until the 25th min, with a minimum value of −16.81 ± 2.10°. Unlike group 1, the MIPS values showed an upward trend after that point. Before the injury, the MIPS values in both group 1 and group 2 did not obviously change within the 30 min measurement. Using a support vector machine at the same time point after injury, the classification accuracy of the two types of severity was shown to be beyond 90%. Combined with CCH pathological mechanisms, this system can not only achieve the detection of early functional changes in CCH but can also distinguish different severities of CCH.

Data mining to understand health status preceding traumatic brain injury

The use of precision medicine is poised to increase in complex injuries such as traumatic brain injury (TBI), whose multifaceted comorbidities and personal circumstances create significant challenges in the domains of surveillance, management, and environmental mapping. Population-wide health administrative data remains a rather unexplored, but accessible data source for identifying clinical associations and environmental patterns that could lead to a better understanding of TBIs. However, the amount of data structured and coded by the International Classification of Disease poses a challenge to its successful interpretation. The emerging field of data mining can be instrumental in helping to meet the daunting challenges faced by the TBI community. The report outlines novel areas for data mining relevant to TBI, and offers insight into how the above approach can be applied to solve pressing healthcare problems. Future work should focus on confirmatory analyses, which subsequently can guide precision medicine and preventive frameworks.

Community Reintegration, Participation, and Employment Issues in Veterans and Service Members With Traumatic Brain Injury

Traumatic brain injury (TBI) has been called the signature injury of the post-9/11 wars in Iraq, Afghanistan, and neighboring countries. Although similarities exist between veterans and service members with TBI, levels of severity and different constellations of coexisting comorbid conditions affect them differently. These conditions affect physical, cognitive, and emotional function, which in turn can complicate community reintegration (CR), or the ability to return to family, vocational, and community life. This special supplement of the Archives of Physical Medicine and Rehabilitation consists of articles written by accomplished teams from multiple disciplines, including anthropology, neuropsychology, nursing, occupational therapy, psychology, and rehabilitation sciences. Each article brings a different perspective to bear on what CR means for veterans and service members from examination of predictors and perceptions of veterans and service members and others to measurement studies. Collectively, this group of articles represents current thinking about CR and lays the groundwork for testing interventions to improve CR outcomes for veterans and service members (eg, employment, living situation, family life).

Pain with traumatic brain injury and psychological disorders

Traumatic brain injury (TBI) is the cause for long-term disability in more than 3 million patients in the US alone, with chronic pain being the most frequently reported complain. To date, predisposing mechanisms for chronic pain in TBI patients are largely unknown. Psychological disorders, including post-traumatic stress disorder, depression and anxiety following TBI are commonly reported comorbidities to post-traumatic pain. Long term consequences can be debilitating and affect quality of life even when the injury is mild. In this review, we present the most commonly reported chronic pain conditions across the spectrum of severity of TBI, mainly focusing on mild TBI. We discuss chronic post- traumatic headaches, widespread pain as well as post-traumatic central pain. We discuss pain in the context of injury severity and military versus civilian populations. We are only starting to understand the biological mechanisms behind post-traumatic pain and associated psychological distress following TBI, with genetic, biochemical and imaging studies pointing to the dopaminergic, neurotrophic factors and the role of Apolipoprotein. Physiological and neurological mechanisms are proposed to partially explain this interaction between post-traumatic pain and psychological distress. Nevertheless, the evidence for the role of structural brain damage remains incomplete and to a large extent debatable, as it is still difficult to establish clear causality between brain trauma and chronic pain. Finally, general aspects of management of chronic pain post-TBI are addressed.

The polytrauma clinical triad in patients with chronic pain after motor vehicle collision

Background

The polytrauma clinical triad (PCT) is a complex disorder composed of three comorbid diagnoses of chronic pain, post-traumatic stress disorder (PTSD), and postconcussion syndrome (PCS). PCT has been documented in veterans returning from deployment, but this is the first report on PCT prevalence in nonmilitary personnel after a motor vehicle collision (MVC).

Methods

Data were drawn from routine intake assessments completed by 71 patients referred to a community-based clinic for chronic pain management. All patients completed the post-traumatic stress disorder checklist for the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (PCL-5), and Rivermead Post-Concussion Symptoms Questionnaire (RPQ) during a standardized intake assessment. An additional modified RPQ score was derived to address previously reported symptom overlap between PCS and chronic pain.

Results

Standard and modified RPQ scores yielded PCS prevalence rates of 100% and 54.9% in our sample, respectively. Results suggest that a modified RPQ score, limited to visual and vestibular symptoms, may be more useful PCS screening criteria in patients with chronic pain. PTSD screening criteria on the PCL-5 were met by 85.9% of the patients. More than half of the patients referred for chronic pain after MVC met criteria for PCT (52.1%). Patients who met PCT criteria reported worse headache, overall pain, and sleep quality outcomes.

Conclusion

Among patients in our sample with chronic pain after MVC, more than half met criteria for PCT. A modified approach to RPQ scoring limited to visual and vestibular symptoms may be required to screen for PCS in these patients.

Mining patterns of comorbidity evolution in patients with multiple chronic conditions using unsupervised multi-level temporal Bayesian network

Over the past few decades, the rise of multiple chronic conditions has become a major concern for clinicians. However, it is still not known precisely how multiple chronic conditions emerge among patients. We propose an unsupervised multi-level temporal Bayesian network to provide a compact representation of the relationship among emergence of multiple chronic conditions and patient level risk factors over time. To improve the efficiency of the learning process, we use an extension of maximum weight spanning tree algorithm and greedy search algorithm to study the structure of the proposed network in three stages, starting with learning the inter-relationship of comorbidities within each year, followed by learning the intra-relationship of comorbidity emergence between consecutive years, and finally learning the hierarchical relationship of comorbidities and patient level risk factors. We also use a longest path algorithm to identify the most likely sequence of comorbidities emerging from and/or leading to specific chronic conditions. Using a de-identified dataset of more than 250,000 patients receiving care from the U.S. Department of Veterans Affairs for a period of five years, we compare the performance of the proposed unsupervised Bayesian network in comparison with those of Bayesian networks developed based on supervised and semi-supervised learning approaches, as well as multivariate probit regression, multinomial logistic regression, and latent regression Markov mixture clustering focusing on traumatic brain injury (TBI), post-traumatic stress disorder (PTSD), depression (Depr), substance abuse (SuAb), and back pain (BaPa). Our findings show that the unsupervised approach has noticeably accurate predictive performance that is comparable to the best performing semi-supervised and the second-best performing supervised approaches. These findings also revealed that the unsupervised approach has improved performance over multivariate probit regression, multinomial logistic regression, and latent regression Markov mixture clustering.

Longitudinal changes in neuroimaging and neuropsychiatric status of post-deployment veterans: a CENC pilot study

PRIMARY OBJECTIVE

The purpose of this study was to evaluate preliminary data on longitudinal changes in psychiatric, neurobehavioural, and neuroimaging findings in Iraq and Afghanistan combat veterans following blast exposure.

RESEARCH DESIGN

Longitudinal observational analysis.

METHODS AND PROCEDURES

Participants were invited to participate in two research projects approximately 7 years apart. For each project, veterans completed the Structured Clinical Interview for DSM-IV Disorders and/or the Clinician-Administered PTSD Scale, Neurobehavioral Symptom Inventory, and magnetic resonance imaging (MRI).

MAIN OUTCOMES AND RESULTS

Chi-squared tests indicated no significant changes in current psychiatric diagnoses, traumatic brain injury (TBI) history, or blast exposure history between assessment visits. Wilcoxon signed-rank tests indicated significant increases in median neurobehavioural symptoms, total number of white matter hyperintensities (WMH), and total WMH volume between assessment visits. Spearman rank correlations indicated no significant associations between change in psychiatric diagnoses, TBI history, blast exposure history, or neurobehavioural symptoms and change in WMH.

CONCLUSION

MRI WMH changes were not associated with changes in psychiatric diagnoses or symptom burden, but were associated with severity of blast exposure. Future, larger studies might further evaluate presence and aetiology of long-term neuropsychiatric symptoms and MRI findings in blast-exposed populations.

Chronic Pain, TBI, and PTSD in Military Veterans: A Link to Suicidal Ideation and Violent Impulses?

The polytrauma clinical triad refers to the co-occurrence of chronic pain, traumatic brain injury (TBI), and posttraumatic stress disorder (PTSD). Despite research implicating dyadic relationships between these conditions and adverse outcomes, scant research has examined the polytrauma clinical triad's relation to suicide or violence. The present cross-sectional study was designed to examine whether this complex clinical presentation increases risk of suicidal ideation and violent impulses after accounting for other established risk factors. Veterans who served in the military since September 11, 2001 (N = 667) who reported chronic pain completed an interview and self-report battery. Bivariate analyses showed that suicidal ideation and violent impulses both correlated with PTSD, TBI+PTSD, pain intensity and interference, drug abuse, and major depressive disorder (MDD). Multiple regression analyses showed that: 1) race, chronic pain with PTSD, alcohol abuse, and MDD significantly predicted suicidal ideation, 2) pain interference, chronic pain with TBI, chronic pain with PTSD, chronic pain with TBI+PTSD, drug abuse, and MDD significantly predicted violent impulses, and 3) pain interference was a more critical predictor of suicidal and violent ideation than pain intensity. Implications for risk assessment and treatment are discussed.

PERSPECTIVE

This article presents results from a study examining predictors of suicide and violence risk among a sample of post-9/11 U.S. Veterans with chronic pain. Health care professionals should assess for pain interference, TBI, PTSD, depression, and alcohol/drug abuse when conducting risk assessments with this population.

Mining Major Transitions of Chronic Conditions in Patients with Multiple Chronic Conditions

OBJECTIVES

Evolution of multiple chronic conditions (MCC) follows a complex stochastic process, influenced by several factors including the inter-relationship of existing conditions, and patient-level risk factors. Nearly 20% of citizens aged 18 years and older are burdened with two or more (multiple) chronic conditions (MCC). Treatment for people living with MCC currently accounts for an estimated 66% of the Nation's healthcare costs. However, it is still not known precisely how MCC emerge and accumulate among individuals or in the general population. This study investigates major patterns of MCC transitions in a diverse population of patients and identifies the risk factors affecting the transition process.

METHODS

A Latent regression Markov clustering (LRMCL) algorithm is proposed to identify major transitions of four MCC that include hypertension (HTN), depression, Post- Traumatic Stress Disorder (PTSD), and back pain. A cohort of 601,805 individuals randomly selected from the population of Iraq and Afghanistan war Veterans (IAVs) who received VA care during three or more years between 2002-2015, is used for training the proposed LRMCL algorithm.

RESULTS

Two major clusters of MCC transition patterns with 78% and 22% probability of membership respectively were identified. The primary cluster demonstrated the possibility of improvement when the number of MCC is small and an increase in probability of MCC accumulation as the number of co- morbidities increased. The second cluster showed stability (no change) of MCC overtime as the major pattern. Age was the most significant risk factor associated with the most probable cluster for each IAV.

CONCLUSIONS

These findings suggest that our proposed LRMCL algorithm can be used to describe and understand MCC transitions, which may ultimately allow healthcare systems to support optimal clinical decision- making. This method will be used to describe a broader range of MCC transitions in this and non-VA populations, and will add treatment information to see if models including treatments and MCC emergence can be used to support clinical decision-making in patient care.