Deployment-related Mild Traumatic Brain Injury Research Articles

Mild traumatic brain injury, PTSD symptom severity, and behavioral dyscontrol: a LIMBIC-CENC study.

Behavioral dyscontrol occurs commonly in the general population and in United States service members and Veterans (SM/V). This condition merits special attention in SM/V, particularly in the aftermath of deployments. Military deployments frequently give rise to posttraumatic stress disorder (PTSD) and deployment-related mild TBI traumatic brain injury (TBI), potentially leading to manifestations of behavioral dyscontrol. Examine associations among PTSD symptom severity, deployment-related mild traumatic brain injury, and behavioral dyscontrol among SM/V. Secondary cross-sectional data analysis from the Long-Term Impact of Military-Relevant Brain Injury Consortium - Chronic Effects of Neurotrauma Consortium prospective longitudinal study among SM/V (N = 1,808). Univariable and multivariable linear regression models assessed the association and interaction effects between PTSD symptom severity, as assessed by the PTSD Checklist for the Diagnostic and Statistical Manual, 5th edition (PCL-5), and deployment-related mild TBI on behavioral dyscontrol, adjusting for demographics, pain, social support, resilience, and general self-efficacy. Among the 1,808 individuals in our sample, PTSD symptom severity (B = 0.23, 95% CI: 0.22, 0.25, p < 0.001) and deployment-related mild TBI (B = 3.27, 95% CI: 2.63, 3.90, p < 0.001) were significantly associated with behavioral dyscontrol in univariable analysis. Interaction effects were significant between PTSD symptom severity and deployment mild TBI (B = -0.03, 95% CI: -0.06, -0.01, p = 0.029) in multivariable analysis, indicating that the effect of mild TBI on behavioral dyscontrol is no longer significant among those with a PCL-5 score > 22.96. Results indicated an association between PTSD symptom severity, deployment-related mild TBI, and behavioral dyscontrol among SM/V. Notably, the effect of deployment-related mild TBI was pronounced for individuals with lower PTSD symptom severity. Higher social support scores were associated with lower dyscontrol, emphasizing the potential for social support to be a protective factor. General self-efficacy was also associated with reduced behavioral dyscontrol.

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

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. 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. 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. 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.

Subjective cognitive complaints and objective cognitive functioning in combat veterans: Effects of PTSD and deployment mild TBI

Objectives (1) Examine the relationship between subjective cognitive complaints and objective cognitive functioning in combat veterans; and (2) evaluate conditional effects of posttraumatic stress disorder (PTSD) and deployment-related mild traumatic brain injury (TBI) within that relationship. Method Combat veterans (N = 225, 86.22% male) completed a lifetime TBI interview, a structured interview assessing PTSD symptoms, a neuropsychological assessment battery, and a self-report measure of cognitive symptoms. Results All correlations between subjective cognitive complaints and objective cognitive measures were not statistically significant. Hierarchical linear regression indicated that cognitive performance was not significantly related to cognitive complaints, but both PTSD diagnosis and history of deployment mild TBI explained a significant amount of unique variance in self-reported cognitive symptoms. Interactions between the studied variables were not significant. Conclusions PTSD and history of deployment mild TBI were uniquely related to cognitive complaints, but cognitive test performance was not. No confounding effects of PTSD or deployment mild TBI were observed in the relationship between cognitive performance and cognitive complaints. This provides support that symptom distress may be a better explanatory factor for perception of lower cognitive functioning than actual cognitive performance.

57 Olfaction in Veterans with a History of Deployment-Related Mild Traumatic Brain Injury

Objective:Olfaction is a critical sensory function and changes in the ability to detect smells could affect quality of life by diminishing appreciation of food, drink, and other aroma-based experiences, increase danger of hazardous exposures, and cause a loss of employment. Additionally, decrements in olfaction have been related to onset of some neurodegenerative conditions. Olfactory impairments in military populations are highly prevalent and often attributed to the long-term effects of mild traumatic brain injury (mTBI) and chronic psychiatric disorders. The main goal of this investigation was to examine olfactory function in a cohort of combat veterans using a quantitative smell test.Participants and Methods:Participants underwent a neurological examination using a revised version of the Neurological Outcome Scale for Traumatic Brain Injury. Olfactory function was examined using a set of essential oil vials with common odors. Based on the number of correctly identified odors, the following grading system was employed: no deficit; mild; moderate; severe deficit; and absence of smell detection. All study assessments were performed prior to March of 2020 (onset of COVID-19 pandemic). In addition, participants completed performance validity testing (PVT) and screening for ongoing substance misuse using the Alcohol Use Disorders Identification Test and Drug Abuse Screening Test-10. Lifetime history of brain injury, combat-related extracranial injuries, and deployment characteristics were assessed using structured interview. All available medical records were reviewed.Results:Participants were 38 veterans with a deployment-related mTBI who passed the PVT and did not have ongoing substance misuse issues. Olfactory examination revealed normosmia in 20 participants and various degrees of deficit in 18 (11= mild; 4=moderate; and 3=severe). The groups did not differ in demographics, post-injury interval, or current clinical (non-psychiatric) conditions. Participants with hyposmia frequently reported being exposed to a higher number of blasts and being positioned closer to the nearest primary blast, and more often endorsed a period of loss of consciousness after the most serious mTBI. In addition, they more often reported tympanic membrane perforation, extracranial injuries, and histories of both blast and blunt force mTBI. Comorbid diagnoses of posttraumatic stress disorder (PTSD), depression, chronic headaches, and pain were more common among these participants as well.Conclusions:Several blast exposure and specific injury-related characteristics increase the likelihood of long-term olfactory impairments, comorbid psychiatric conditions, and chronic pain among veterans with a history of deployment-related mTBI. Notably, none of the participants with hyposmia had a clinical diagnosis of olfactory dysfunction or were receiving service-connected disability for a loss of sense of smell at the time of their assessment. Multidisciplinary rehabilitation care provided to combat veterans with history of mTBI and/or PTSD should include olfactory examination using both quantitative and qualitative smell tests, education regarding the adversities related to loss of smell, management of current psychiatric symptoms, and follow-up assessments. The lack of a comparison group without a history of mTBI and the small sample size were the main limitations of this investigation.

Associations between health-related behaviors and self-reported cognitive symptoms in U.S. military personnel injured on deployment

Health behaviors may be core contributors to cognition and mental health following mild traumatic brain injury (TBI). The aims of the present study examined: (1) whether health behaviors including sleep duration, alcohol use, and physical activity differed in injured military personnel with and without deployment-related mild TBI history and (2) the relative contributions of health behaviors and deployment-related mild TBI history to self-reported cognitive, posttraumatic stress disorder (PTSD), and depressive symptoms. Participants included 3076 military personnel injured on deployment participating in the Wounded Warrior Recovery Project, an ongoing web-based study. Military personnel with deployment-related mild TBI history reported similar rates of physical activity and levels of alcohol problems as those without, but were less likely to report receiving the recommended duration of sleep. When adjusting for demographic and injury variables, all three health behaviors were associated with cognitive, PTSD, and depressive symptoms. Alcohol problems demonstrated significant but small effects across all outcomes measures (ηp2=.01) whereas physical activity was associated with slightly larger effects albeit still within the small range (ηp2=.02-0.04). Duration of sleep bordered a medium effect for cognitive symptoms (ηp2=.05) and was in the medium range for PTSD and depressive symptoms (ηp2=.06). Although deployment-related mild TBI history was significant in all models, effect sizes were small (ηp2=.01). Findings from the present study provide support that health behaviors have stronger effects with regard to cognitive, PTSD, and depressive symptoms compared to deployment-related mild TBI history in military personnel and, given their modifiable nature, may represent treatment targets in this population.

A pilot study of olfactory function in veterans with a history of deployment-related mild traumatic brain injury

ABSTRACT Olfactory impairment in military populations is highly prevalent and often attributed to the long-term effects of mild traumatic brain injury (mTBI) and chronic psychiatric disorders. The main goal of this investigation was to examine olfactory function in a cohort of combat veterans using a quantitative smell test. Participants underwent a neurological examination, completed performance validity testing (PVT), provided deployment history, and their medical records were reviewed. Participants were 38 veterans with a deployment-related mTBI who passed the PVT and did not have ongoing substance misuse issues. Olfactory examination revealed normosmia in 20 participants and various degrees of deficit in 18. The groups did not differ in demographics, post-injury interval, or current clinical (non-psychiatric) conditions. Participants with hyposmia frequently reported being exposed to a higher number of blasts and being positioned closer to the nearest primary blast, and more often endorsed a period of loss of consciousness after the most serious mTBI. In addition, they more often reported tympanic membrane perforation, extracranial injuries, and histories of both blast and blunt force mTBI. Comorbid diagnoses of posttraumatic stress disorder, depression, chronic headaches, and pain were more common among them as well. Several blast exposure and injury-related characteristics increase the likelihood of long-term olfactory impartments, comorbid psychiatric conditions, and chronic pain among veterans with history of deployment-related mTBI. Notably, none of the participants with hyposmia had a clinical diagnosis of olfactory dysfunction or were receiving service-connected disability for loss of sense of smell at the time of their assessment.

Risk factors for decline in cognitive performance following deployment-related mild traumatic brain injury: A preliminary report

ABSTRACT Thorough identification of risk factors for delayed decline in cognitive performance following combat-related mild traumatic brain injury (mTBI) is important for guiding comprehensive post-deployment rehabilitation. In a sample of veterans who reported at least one deployment-related mTBI, preliminary results indicate that factors including a history of loss of consciousness over 1 min, current obesity and hypertension, and Black race were more prevalent in those with decreased scores on a measure of memory function. These factors should be considered by clinicians and researchers working with current and former military personnel.

Health symptoms after war zone deployment-related mild traumatic brain injury: contributions of mental disorders and lifetime brain injuries

ABSTRACT Primary Objective To gain a better understanding of the complex relationship between combat deployment-related mild traumatic brain injury (mTBI) and persistent post-concussive symptoms (PPCSs), taking into consideration a wide range of potentially mediating and confounding factors. Research Design Cross-sectional. Methods and Procedures Subjects were 613 U. S. military Veterans and Service Members who served during operations Enduring Freedom, Iraqi Freedom, or New Dawn (OEF/OIF/OND) and completed a structured interview of mental disorders and a battery of questionnaires. Hierarchical binary logistic regression analyses were used to test the hypotheses. Main Outcomes and Results After accounting for mental disorders, lifetime mTBIs outside of OEF/OIF/OND deployment, medical conditions, and injury/demographic characteristics, deployment-related mTBI continued to be associated with several PPCSs (headaches, sleep disturbance, and difficulty making decisions). Deployment-related mTBI was also associated with two symptoms not normally associated with mTBI (nausea/upset stomach and numbness/tingling). Conclusions After adjusting for a wide range of factors, OEF/OIF/OND deployment-related mTBI was still associated with PPCSs on average 10 years after the injury. These findings suggest that mTBI sustained during OEF/OIF/OND deployment may have enduring negative health effects. More studies are needed that prospectively and longitudinally track health and mental health outcomes after TBI.

Potential Concussive Event Narratives of Post-9/11 Combat Veterans: Chronic Effects of Neurotrauma Consortium Study.

Deployment-related mild traumatic brain injury (mTBI) affects a significant proportion of those who served in Post-9/11 combat operations. The prevalence of head injuries, including those that lead to mTBI, is often reported quantitatively. However, service member (SM) and Veteran firsthand accounts of their potential concussive events (PCEs) and mTBIs can serve as a rich resource for better understanding the nuances and context of these exposures. Post-9/11 SMs and Veterans with a history of combat deployment were recruited through the Chronic Effects of Neurotrauma Consortium's observational study of deployment-related mTBI. During a comprehensive assessment, participants completed the Virginia Commonwealth University retrospective Concussion Diagnostic Interview, a specialized validated interview measure which obtains detailed narratives of deployment-incurred blast and non-blast-related PCEs. Qualitative thematic analysis was used to identify and code recurring themes within the narratives. Among the sample of 106 SMs and Veterans, deployment-related mTBI was highly prevalent (67.0%). Over half (50.9%) of the participants identified a blast as the cause of their worst PCE, frequently with accompanying themes of self-reported acute neurological symptoms, intense physical blast forces, and tertiary head impact. Exposure to blast at close range, such as driving directly over an improvised explosive device, occurred in 24.7% of all blast-related narratives and in 59.3% of narratives where blast was identified as causing the worst PCE. Themes of potentially preventable head impacts experienced during noncombat circumstances were also frequent, accounting for 35% of all non-blast-related head injuries in the sample. Prevalence of deployment-related close-range blast exposure, non-blast impact PCEs, and mTBIs among this Post-9/11 combatant sample was substantial, and in many cases potentially preventable. The use of detailed semi-structured interviews may help health care providers and policymakers to better understand the context and circumstances of deployment-related PCEs and mTBIs.

Testosterone and Resting State Connectivity of the Parahippocampal Gyrus in Men With History of Deployment-Related Mild Traumatic Brain Injury.

The purpose of this study was to explore the effect of low testosterone level on whole-brain resting state (RS) connectivity in male veterans with symptoms such as sleep disturbance, fatiguability, pain, anxiety, irritability, or aggressiveness persisting after mild traumatic brain injury (mTBI). Follow-up analyses were performed to determine if sleep scores affected the results. In our cross-sectional design study, RS magnetic resonance imaging scans on 28 veterans were performed, and testosterone, sleep quality, mood, and post-traumatic stress symptoms were measured. For each participant, we computed the average correlation of each voxel's time-series with the rest of the voxels in the brain, then used AFNI's 3dttest++ on the group data to determine whether the effects of testosterone level on whole-brain connectivity were significant. We then performed follow-up region of interest-based RS analyses of testosterone, with and without sleep quality as a covariate. The study protocol was approved by the National Institute of Health's Combined Neuroscience Institutional Review Board. Sixteen participants reported repeated blast exposure in theater, leading to symptoms; the rest reported exposure to a single blast or a nonblast TBI. Thirty-three percent had testosterone levels <300ng/dL. Testosterone level was lower in participants who screened positive for post-traumatic stress disorder compared to those who screened negative, but it did not reach statistical significance. Whole-brain connectivity and testosterone level were positively correlated in the left parahippocampal gyrus (LPhG), especially in its connectivity with frontal areas, the lingual gyrus, cingulate, insula, caudate, and right parahippocampal gyrus. Further analysis revealed that the effect of testosterone on LPhG connectivity is only partially mediated by sleep quality. Sleep quality by itself had an effect on connectivity of the thalamus, cerebellum, precuneus, and posterior cingulate. Lower testosterone levels were correlated with lower connectivity of the LPhG. Weaknesses of this study include a retrospective design based on self-report of mTBI and the lack of a control group without TBI. Without a control group or pre-injury testosterone measures, we were not able to attribute the rate of low testosterone in our participants to TBI per se. Also testosterone levels were checked only once. The high rate of low testosterone level that we found suggests there may be an association between low testosterone level and greater post-traumatic stress disorder symptoms following deployment, but the causality of the relationships between TBI and deployment stress, testosterone level, behavioral symptomatology, and LPhG connectivity remains to be determined. Our study on men with persistent symptoms postdeployment and post-mTBI may help us understand the role of low testosterone and sleep quality in persistent symptoms and may be important in developing therapeutic interventions. Our results highlight the role of the LPhG, as we found that whole-brain connectivity in that region was positively associated with testosterone level, with only a limited portion of that effect attributable to sleep quality.

Prevalence and Severity of Psychiatric Disorders and Suicidal Behavior in Service Members and Veterans With and Without Traumatic Brain Injury: Systematic Review.

Assess prevalence and severity of posttraumatic stress disorder, suicidal behavior, and depressive, substance use, and anxiety disorders in US service members or Veterans with and without a deployment-related mild traumatic brain injury (TBI) (mTBI). Systematic review using multiple databases (January 2000 to October 2017). We included national or geographically diverse samples. Prevalence and severity of psychiatric conditions based on diagnostic codes, clinician assessments, and self-report measures with results stratified by sample type. We identified 11 studies on the basis of national samples and 22 studies on the basis of geographically diverse samples. Traumatic brain injury severity was not always ascertained or reported. In national studies, posttraumatic stress disorder, depressive disorder, substance use disorder, and anxiety disorder prevalence were higher in those with TBI than in those without. One national sample reported prevalence of suicide attempts. Across psychiatric conditions, strength of evidence ranged from insufficient to moderate. In geographically diverse samples, the pattern of findings was similar. National studies provided insufficient evidence on psychiatric condition severity; geographically diverse studies found greater severity of posttraumatic stress disorder symptoms with mixed results for symptoms of depressive or substance use disorders. Service members and Veterans with TBI history have higher prevalence and possibly severity of selected psychiatric conditions.

Correction to: Prognostic Indicators of Persistent Post-Concussive Symptoms after Deployment-Related Mild Traumatic Brain Injury: A Prospective Longitudinal Study in U.S. Army Soldiers; DOI: 10.1089/neu.2015.4320.

Correction to: Prognostic Indicators of Persistent Post-Concussive Symptoms after Deployment-Related Mild Traumatic Brain Injury: A Prospective Longitudinal Study in U.S. Army Soldiers; DOI: 10.1089/neu.2015.4320.

Expressions of emotional distress in active duty military personnel with mild traumatic brain injury: A qualitative content analysis

ABSTRACTService members (SMs) who sustain traumatic brain injury (TBI) during deployment have increased risk for mental health issues. Mental health treatment can be challenging in military settings where treatment seeking is often stigmatized. Adequate care relies on accurate interpretations of SMs’ verbal accounts of distress, but little is known about how SMs, embedded in a culture that values resilience and self-reliance, relay emotional distress. We performed qualitative analyses of recordings from a telephone-based intervention with 25 SMs who sustained deployment-related mild TBI (mTBI) to elucidate thematic and dialectal patterns. Consistent with our expectations, SMs rarely used explicit depressive terms while discussing their emotional distress. More prevalent was language suggestive of an overarching theme of loss of control, whereby SMs’ stress, anxiety, and anger were often attributable to SMs’ perceptions that they had incomplete jurisdiction over their own lives. This study may help mental health providers improve engagements with SMs and Veterans, preventing misunderstandings and even improper diagnoses or referrals that could result from a strict reliance on the more customary expressions of distress.

Deployment-Related Traumatic Brain Injury and Risk of New Episodes of Care for Back Pain in Veterans

Traumatic brain injury (TBI) may be a predisposing factor to pain syndromes other than headache. We conducted a longitudinal cohort study among veterans evaluated for TBI in the US Department of Veterans Affairs (VA). Among 36,880 veterans at baseline, 55% reported back pain. TBI history was classified by trained clinicians according to VA-US Department of Defense criteria. 14,223 Veterans without back pain were followed for up to 6 years for new (incident) episodes of VA care for back pain. We estimated adjusted odds ratios (aORs), adjusted hazard ratios (aHRs), and 95% confidence intervals (CI), accounting for covariates. Deployment-related mild TBI was significantly associated with self-reported back pain in cross-sectional analyses (aOR = 1.27, 95% CI = 1.21–1.35), but not with incident episodes of VA care for back pain in longitudinal analysis (aHR = 1.07, 95% CI = 0.99–1.17). Deployment-related moderate to severe TBI was significantly associated with self-reported back pain in cross-sectional (aOR = 1.74, 95% CI = 1.58–1.91), and longitudinal analyses (aHR = 1.20, 95% CI = 1.05–1.38; P = .01). These findings indicate that deployment-related moderate to severe TBI confers increased back pain risk, but do not support a causal effect of deployment-related mild TBI on back pain. PerspectiveFindings from this longitudinal study of veterans indicate that deployment-related moderate to severe TBI confers increased back pain risk, but do not support a causal effect of deployment-related mild TBI on back pain.

Characterization of pain and fatigue following deployment-related mild traumatic brain injury (P5.149)

Characterization of pain and fatigue following deployment-related mild traumatic brain injury (P5.149)

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

ObjectiveDeployment-related mild traumatic brain injury (MTBI) occurs in a significant number of military personnel but its long-term impacts are unclear. This study explores the impact of deployment-related MTBI on continued...

Prognostic Indicators of Persistent Post-Concussive Symptoms after Deployment-Related Mild Traumatic Brain Injury: A Prospective Longitudinal Study in U.S. Army Soldiers.

Mild traumatic brain injury (mTBI), or concussion, is prevalent in the military. The course of recovery can be highly variable. This study investigates whether deployment-acquired mTBI is associated with subsequent presence and severity of post-concussive symptoms (PCS) and identifies predictors of persistent PCS among US Army personnel who sustained mTBI while deployed to Afghanistan. We used data from a prospective longitudinal survey of soldiers assessed 1-2 months before a 10-month deployment to Afghanistan (T0), on redeployment to the United States (T1), approximately 3 months later (T2), and approximately 9 months later (T3). Outcomes of interest were PCS at T2 and T3. Predictors considered were: sociodemographic factors, number of previous deployments, pre-deployment mental health and TBI history, and mTBI and other military-related stress during the index deployment. The study sample comprised 4518 soldiers, 822 (18.2%) of whom experienced mTBI during the index deployment. After adjusting for demographic, clinical, and deployment-related factors, deployment-acquired mTBI was associated with nearly triple the risk of reporting any PCS and with increased severity of PCS when symptoms were present. Among those who sustained mTBI, severity of PCS at follow-up was associated with history of pre-deployment TBI(s), pre-deployment psychological distress, more severe deployment stress, and loss of consciousness or lapse of memory (versus being "dazed" only) as a result of deployment-acquired mTBI. In summary, we found that sustaining mTBI increases risk for persistent PCS. Previous TBI(s), pre-deployment psychological distress, severe deployment stress, and loss of consciousness or lapse of memory resulting from mTBI(s) are prognostic indicators of persistent PCS after an index mTBI. These observations may have actionable implications for prevention of chronic sequelae of mTBI in the military and other settings.

Soldiers returning from deployment: A qualitative study regarding exposure, coping, and reintegration.

The purpose of this study was to qualitatively explore exposure to deployment-related physical and/or emotional trauma and associated symptoms among Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) soldiers. Interviews also focused on in-theater- and reintegration-related experiences. OEF/OIF soldiers (N = 103) participated in semistructured interviews, and a qualitative descriptive methodology was used to analyze the data. Themes were identified regarding (a) common experiences related to emotional and physical traumas and associated symptoms and strategies for coping and making meaning of experiences and (b) how combat and reintegration experiences affected soldiers' senses of self, relationships with others, and functioning. Themes identified support a rethinking of deployment-related mild traumatic brain injury and posttraumatic stress disorder as discrete conditions. Dimensional versus categorical models should be considered. The findings also highlight experiences and potentially meaningful constructs (e.g., moral injury, moral repair) that can be used to inform research and clinical efforts aimed at improving the lives of those who have served.

Suicidal Ideation among Florida National Guard Members: Combat Deployment and Non-Deployment Risk and Protective Factors

This study examined relationships among risk/protective factors and suicidal ideation (SI) in deployed and non-deployed National Guard members, particularly examining for possible differential effects of deployment on SI. A total of 3,098 Florida National Guard members completed an anonymous online survey that assessed variables associated with SI including demographics, current psychiatric diagnoses, and pre-, during, and post-deployment experiences. Those deployed had significantly higher rates of SI (5.5%) than those not deployed (3.0%; p < .001). In multivariate analyses, among those not deployed, SI was significantly associated with major depressive disorder (p < .001), posttraumatic stress disorder (PTSD) (p < .001), prior psychological trauma (p < .01), and heavy/hazardous alcohol consumption (p < .05). In contrast, in the deployed, only PTSD (p < .001) and deployment-related mild traumatic brain injury (p < .05) were independently associated with SI. Risk and protective factors differed by deployment status in National Guard members suggesting the possible need for cohort-specific treatment targets to minimize SI.

Deployment-related mild traumatic brain injury, mental health problems, and post-concussive symptoms in Canadian Armed Forces personnel.

BackgroundUp to 20% of US military personnel deployed to Iraq or Afghanistan experience mild traumatic brain injury (mTBI) while deployed; up to one-third will experience persistent post-concussive symptoms (PCS). The objective of this study was to examine the epidemiology of deployment-related mTBI and its relationship to PCS and mental health problems (MHPs) in Canadian Armed Forces (CAF) personnel.MethodsParticipants were 16153 personnel who underwent post-deployment screening (median =136 days after return) following deployment in support of the mission in Afghanistan from 2009 – 2012. The screening questionnaire assessed mTBI and other injuries while deployed, using the Brief Traumatic Brain Injury Screening Tool. Current MHPs and PCS were assessed using items from the Patient Health Questionnaire, the Patient Checklist for PTSD, and the Cognitive Failures Questionnaire. Log-binomial regression explored the association of mTBI, other injuries, and MHPs with PCS, using the presence of 3 or more of 7 PCS as the outcome. Results are expressed as adjusted prevalence ratios (PR).ResultsmTBI while deployed was reported in 843 respondents (5.2%). Less severe forms of mTBI (associated only with having been dazed or confused or having “seen stars”) predominated. Blast was reported as a mechanism of injury in half of those with mTBI. Multiple PCS were present in 21% of those with less severe forms of mTBI and in 27% of those with more severe forms of mTBI (i.e., mTBI associated with loss of consciousness or post-traumatic amnesia). After adjustment for confounding, mTBI had no statistically significant association with PCS relative to non-TBI injury. In contrast, MHPs had a strong association with reporting 3 or more PCS (adjusted prevalence ratio (PR) =7.77).ConclusionDeployment-related mTBI prevalence was lower than in many US reports; most of those who had had mTBI were free of multiple PCS. PCS was strongly associated with MHPs but not with mTBI. Careful assessment of MHPs is essential in personnel with a history of combat-related mTBI and PCS.