Identifying Unique Symptom Groups Following Mild Traumatic Brain Injury Using the Neurobehavioral Symptom Inventory and PTSD Checklist-5 in Military Personnel: A Bifactor Analysis.

OBJECTIVE: To identify both shared and unique groups of posttraumatic stress and postconcussive symptoms using bifactor analysis. SETTING: Two large military outpatient traumatic brain injury (TBI) rehabilitation clinics in the Southwestern United States. PARTICIPANTS: A sample of 1476 Active Duty Service Members seeking treatment for a mild TBI sustained more than 30 days previously, without history of moderate or severe TBI, who completed measures of postconcussive and posttraumatic stress symptoms assessed at clinic intake. DESIGN: Observational, correlational study with data taken from an institutional review board-approved clinical registry study. MAIN MEASURES: Neurobehavioral Symptom Inventory (NSI) and Posttraumatic Stress Disorder (PTSD) Checklist for Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) ( DSM-V ) (PCL-5). Concurrent measures were Patient Health Questionnaire (PHQ-8), Pittsburgh Sleep Quality Index (PSQI), and Headache Impact Test (HIT-6). RESULTS: Results identified a bifactor model demonstrating unique posttraumatic stress, depressive, cognitive, and neurological/somatic symptom groups that were still evident after accounting for a universal factor representing general distress. These symptom groups were differentially related to concurrently measured clinical outcomes. CONCLUSION: Use of a bifactor structure may help derive clinically useful signals from self-reported symptoms among Active Duty Service Members seeking outpatient treatment for mild TBI.

Elevated Serum Tau and UCHL-1 Concentrations Within 12 Months of Injury Predict Neurobehavioral Functioning 2 or More Years Following Traumatic Brain Injury: A Longitudinal Study.

OBJECTIVE: Blood-based biomarkers have received considerable attention for their diagnostic and prognostic value in the acute and postacute period following traumatic brain injury (TBI). The purpose of this study was to examine whether blood-based biomarker concentrations within the first 12 months of TBI can predict neurobehavioral outcome in the chronic phase of the recovery trajectory. SETTING: Inpatient and outpatient wards from 3 military medical treatment facilities. PARTICIPANTS: A total of 161 service members and veterans classified into 3 groups: (a) uncomplicated mild TBI (MTBI; n = 37), (b) complicated mild, moderate, severe, penetrating TBI combined (STBI; n = 46), and (c) controls (CTRL; n = 78). DESIGN: Prospective longitudinal. MAIN MEASURES: Participants completed 6 scales from the Traumatic Brain Injury Quality of Life (ie, Anger, Anxiety, Depression, Fatigue, Headaches, and Cognitive Concerns) within 12 months (baseline) and at 2 or more years (follow-up) post-injury. Serum concentrations of tau, neurofilament light, glial fibrillary acidic protein, and UCHL-1 at baseline were measured using SIMOA. RESULTS: Baseline tau was associated with worse anger, anxiety, and depression in the STBI group at follow-up (R2 = 0.101-0.127), and worse anxiety in the MTBI group (R2 = 0.210). Baseline ubiquitin carboxyl-terminal hydrolase L1 (UCHL-1) was associated with worse anxiety and depression at follow-up in both the MTBI and STBI groups (R2Δ = 0.143-0.207), and worse cognitive concerns in the MTBI group (R2Δ = 0.223). CONCLUSIONS: A blood-based panel including these biomarkers could be a useful tool for identifying individuals at risk of poor outcome following TBI.

Risk factors for the presence and persistence of posttraumatic stress symptoms following traumatic brain injury in U.S. service members and veterans.

This study aimed to identify risk factors predictive of the presence and persistence of posttraumatic stress disorder (PTSD) symptom reporting following traumatic brain injury (TBI). Participants were 1,301 U.S. service members and veterans (SMVs) divided into four groups: uncomplicated mild TBI (mTBI; n = 543); complicated mild, moderate, severe, and penetrating TBI (n = 230); injured controls (n = 340); and noninjured controls (n = 188). We examined 25 factors related to demographic, injury-related, military-specific, treatment/health care need, and mental health/social support variables. Seven factors were statistically associated with the presence of DSM-IV-TR symptom criteria for PTSD: premorbid IQ, combat exposure, depression, social participation, history of mTBI, need for managing mood and stress, and need for improving memory and attention, p < .001 (51.3% variance). When comparing the prevalence of these risk factors in a longitudinal cohort (n = 742) across four PTSD trajectory groups (i.e., asymptomatic, improved, developed, persistent), a higher proportion of participants in the persistent PTSD group reported worse depression, a lack of social participation, and history of mTBI. Additionally, a higher proportion of participants in the persistent and developed PTSD groups reported the need for managing mood/stress and improving memory/attention. When considered simultaneously, the presence of ≥ 1 or ≥ 2 risk factors was associated with a higher proportion of participants in the developed and persistent PTSD groups, ps < .001. These risk factors may be useful in identifying SMVs at risk for the development and/or persistence of PTSD symptoms who may need intervention.

Impact of depression and post-traumatic stress on manual and oculomotor performance in service members with a history of mild TBI.

OBJECTIVE: To determine the impact of depression and post-traumatic stress on an automated oculomotor and manual measure of visual attention, compared to conventional neuropsychological assessment. Setting: Military traumatic brain injury (TBI) rehabilitation program. PARTICIPANTS: 188 Active Duty Service Members (ADSM) with a history of mild TBI. DESIGN: A cross-sectional and correlational study with data obtained through an IRB-approved data registry study. Main measures: Bethesda Eye & Attention Measure (BEAM); brief neuropsychological battery; self-reported symptom surveys including Neurobehavioral Symptom Inventory (NSI), Patient Health Questionnaire-8 (PHQ-8), and PTSD Checklist-5 (PCL-5). RESULTS: Small effect sizes were found for partial correlations between both depression and post-traumatic stress and key BEAM metrics. In contrast, small-to-medium effects sizes were found across all traditional neuropsychological test measures. CONCLUSION: This study illustrates the profile of impairments associated with depression and post-traumatic stress on saccadic eye movements and manual responses to BEAM relative to conventional neuropsychological tests. Results demonstrated that among ADSM seen for mTBI, depression and PTS exert a significant negative impact on measures of processing speed, attention, executive function, and memory across saccadic, manual, and conventional neuropsychological tests. However, the unique psychometric features of each of these assessment approaches may assist in distinguishing the effects of psychiatric comorbidities within this population.

Clinical utility of PTSD, resilience, sleep, and blast as risk factors to predict poor neurobehavioral functioning following traumatic brain injury: A longitudinal study in U.S. military service members.

PURPOSE: This study examined the clinical utility of post-traumatic stress disorder (PTSD), low resilience, poor sleep, and lifetime blast exposure as risk factors for predicting future neurobehavioral outcome following traumatic brain injury (TBI). METHODS: Participants were 591 U.S. military service members and veterans who had sustained a TBI (n = 419) or orthopedic injury without TBI (n = 172). Participants completed the Neurobehavioral Symptom Inventory, PTSD Checklist, and the TBI-Quality of Life (TBI-QOL) scale at baseline and follow-up. RESULTS: Using the four risk factors at baseline, 15 risk factor combinations were examined by calculating odds ratios to predict poor neurobehavioral outcome at follow-up (i.e., number of abnormal scores across five TBI-QOL scales [e.g., Fatigue, Depression]). The vast majority of risk factor combinations resulted in odds ratios that were considered to be clinically meaningful (i.e., ≥ 2.5) for predicting poor outcome. The risk factor combinations with the highest odds ratios included PTSD singularly, or in combination with poor sleep and/or low resilience (odds ratios = 4.3-72.4). However, poor sleep and low resilience were also strong predictors in the absence of PTSD (odds ratios = 3.1-29.8). CONCLUSION: PTSD, poor sleep, and low resilience, singularly or in combination, may be valuable risk factors that can be used clinically for targeted early interventions.

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.

Multimodal Neurocognitive Screening of Military Personnel With a History of Mild Traumatic Brain Injury Using the Bethesda Eye & Attention Measure.

OBJECTIVE: To evaluate a neurocognitive eye tracking task, the Bethesda Eye & Attention Measure (BEAM), for use in cognitive screening of patients with a history of mild traumatic brain injury (TBI). SETTING: US military TBI rehabilitation clinic. DESIGN/PARTICIPANTS: Cross-sectional study of 191 military personnel receiving outpatient services related to history of mild TBI. Main measures: BEAM; neuropsychological screening measures of attention, processing speed, executive function, and memory. RESULTS: Medium effect sizes were found for partial correlations (controlling for age) between key BEAM metrics and neuropsychological screening tests. Linear regression analyses demonstrated that BEAM saccadic eye movements and manual (button press) metrics each provided complementary value in measurement of cognitive performance, above and beyond effects of demographic factors and clinical characteristics. CONCLUSION: This study provides initial support for the use of BEAM neurocognitive eye tracking in cognitive screening of adults with a history of mild TBI. BEAM saccadic metrics appear to be particularly well-suited for the assessment of visual attention. Study findings also highlight opportunities for greater cognitive sensitivity or testing efficiency that may be missed by tests measuring only one response modality at a time.

Intracranial Abnormalities Are Associated With Fewer Self-Reported Symptoms in Military Service Members Following Moderate-to-Severe Traumatic Brain Injury.

OBJECTIVE: This study examined the relationship between intracranial abnormalities (ICAs) and self-reported neurobehavioral and posttraumatic stress (PTS) symptoms in members of the military with moderate-to-severe traumatic brain injury (msTBI). METHOD: Participants included 539 members of the US military with nonpenetrating msTBI. Self-reported neurobehavioral and PTS symptoms were assessed using the Neurobehavioral Symptom Inventory and the PTSD Checklist-Civilian Version. ICAs were categorized as present/absent (by subtype) based upon medical record review. Spearman rank-order correlations and stepwise multiple regression analyses examined univariate and combined predictive relationships between ICAs and self-reported symptoms. RESULTS: The presence of any ICA was associated with reduced self-reported neurobehavioral and PTS symptoms. ICA-associated reductions were largest for PTS, followed by affective and cognitive neurobehavioral symptoms, and relatively weak for somatic/sensory and vestibular symptoms. Effects of different types of ICAs were comparable. Greater time since injury was related to greater symptom report, whereas duration of loss of consciousness and posttraumatic amnesia were not consistently related to self-reported symptoms. CONCLUSIONS: Results suggest that ICAs are associated with suppression of reported PTS and neurobehavioral symptoms-potentially via reduction in self-awareness. These findings support comprehensive, objective evaluation to identify impairments in self-awareness and functioning in msTBI patients.

Saccadic impairment in chronic traumatic brain injury: examining the influence of cognitive load and injury severity.

OBJECTIVE: Previous research suggests that saccadic eye movements can be uniquely sensitive to impairment in chronic traumatic brain injury (TBI). This study was conducted to examine saccadic eye movements across varying levels of cognitive load and TBI history/severity. We hypothesized that saccadic impairment in chronic mild and moderate-severe TBI would be most pronounced under conditions of high cognitive load. METHODS: In total, 61 participants (including n = 20 with chronic mild TBI, n = 15 with chronic moderate-severe TBI, and 26 uninjured controls) completed a battery of conventional neuropsychological tests and the Fusion n-Back Test, which measures manual and saccadic response time (RT) across varying cognitive load and cueing conditions. RESULTS: Consistent with our hypotheses, chronic mild and moderate-severe TBI were associated with substantial saccadic impairment under conditions of high cognitive load. Participants with moderate-severe TBI also demonstrated saccadic impairment at low levels of cognitive load. TBI groups and uninjured controls did not differ significantly on manual metrics or conventional neuropsychological measures. CONCLUSIONS: This study provides additional support for the value of eye tracking for enhanced assessment of TBI. Additionally, findings suggest that TBI is associated with greatest susceptibility to oculomotor interference under high levels of cognitive load.

White Matter Organization and Cortical Thickness Differ Among Active Duty Service Members With Chronic Mild, Moderate, and Severe Traumatic Brain Injury.

Abstract This study compared findings from whole-brain diffusion tensor imaging (DTI) and volumetric magnetic resonance imaging (MRI) among 90 Active Duty Service Members with chronic mild traumatic brain injury (TBI; n = 52), chronic moderate-to-severe TBI (n = 17), and TBI-negative controls (n = 21). Data were collected on a Philips Ingenia 3T MRI with DTI in 32 directions. Results demonstrated that history of TBI was associated with differences in white matter microstructure, white matter volume, and cortical thickness in both mild TBI and moderate-to-severe TBI groups relative to controls. However, the presence, pattern, and distribution of these findings varied substantially depending on the injury severity. Spatially-defined forms of DTI fractional anisotropy (FA) analyses identified altered white matter organization within the chronic moderate-to-severe TBI group, but they did not provide clear evidence of abnormalities within the chronic mild TBI group. In contrast, DTI FA "pothole" analyses identified widely distributed areas of decreased FA throughout the white matter in both the chronic mild TBI and chronic moderate-to-severe TBI groups. Additionally, decreased white matter volume was found in several brain regions for the chronic moderate-to-severe TBI group compared with the other groups. Greater number of DTI FA potholes and reduced cortical thickness were also related to greater severity of self-reported symptoms. In sum, this study expands upon a growing body of literature using advanced imaging techniques to identify potential effects of brain injury in military Service Members. These findings may differ from work in other TBI populations due to varying mechanisms and frequency of injury, as well as a potentially higher level of functioning in the current sample related to the ability to maintain continued Active Duty status after injury. In conclusion, this study provides DTI and volumetric MRI findings across the spectrum of TBI severity. These results provide support for the use of DTI and volumetric MRI to identify differences in white matter microstructure and volume related to TBI. In particular, DTI FA pothole analysis may provide greater sensitivity for detecting subtle forms of white matter injury than conventional DTI FA analyses.

Cumulative Blast Exposure During a Military Career Negatively Impacts Recovery from Traumatic Brain Injury.

Sub-concussive injuries have emerged as an important factor in the long-term brain health of athletes and military personnel. The objective of this study was to explore the relationship between service member and veterans (SMVs) lifetime blast exposure and recovery from a traumatic brain injury (TBI). A total of 558 SMVs with a history of TBI were examined. Lifetime blast exposure (LBE) was based on self-report (M = 79.4, standard deviation = 392.6; range = 0-7500) categorized into three groups: Blast Naive (n = 121), Low LBE (n = 223; LBE range 1-9), and High LBE (n = 214; LBE >10). Dependent variables were the Neurobehavioral Symptom Inventory (NSI) and Post-traumatic Stress Disorder Checklist-Civilian (PCL-C) and the Traumatic Brain Injury Quality of Life (TBI-QOL). Analyses controlled for demographic factors (age, gender, and race) as well as TBI factors (months since index TBI, index TBI severity, and total number lifetime TBIs). The Blast Naive group had significantly lower NSI and PCL-C scores compared with the Low LBE group and High LBE group, with small to medium effect sizes. On the TBI-QOL, the Blast Naïve group had better quality life on 10 of the 14 scales examined. The Low LBE did not differ from the High LBE group on the PCL-C, NSI, or TBI-QOL. Blast exposure over an SMV's career was associated with increased neurobehavioral and post-traumatic stress symptoms following a TBI. The influence of psychological trauma associated with blasts may be an important factor influencing symptoms as well as the accuracy of self-reported estimates of LBE.

Convergent and Discriminant Validity of the Blast Exposure Threshold Survey in United States Military Service Members and Veterans.

The Blast Exposure Threshold Survey (BETS) is a recently developed and promising new self-report measure of lifetime blast exposure (LBE). However, there are no studies that have examined the psychometric properties of the BETS, which currently limits its clinical utility. The purpose of this study was to examine the convergent and discriminant validity of the BETS by comparing the BETS Generalized Blast Exposure Value (GBEV) to six variables hypothesized to be associated with LBE (i.e., single-item LBE, combat exposure, years in the military, number of combat deployments, and military occupation specialty [MOS]) and three variables hypothesized not to be associated with LBE (i.e., age at the time of injury, estimated pre-morbid Full-Scale Intelligence Quotient [FSIQ], and resilience). Participants were 202 United States service members and veterans prospectively enrolled from three military medical treatment facilities (68.7%) and via community recruitment initiatives (31.3%). Participants completed the BETS, Combat Exposure Scale (CES), Deployment Risk and Resiliency Inventory-2 Combat Experiences (DRRI-2 CE), Traumatic Brain Injury-Quality of Life Resilience scale, and a brief structured interview. For some analyses, participants were classified into two blast risk MOS groups: high (n = 89) and low (n = 94). The BETS GBEV was not significantly correlated with all three non-blast related variables (rs = 0.01 to rs = -0.12). In contrast, GBEV was significantly (p < 0.001) associated with all blast-related variables; single-item LBE (rs = 0.76), CES (rs = 0.58), number of combat deployments (rs = 0.53), DRRI-2 CE (rs = 0.48), and high blast risk MOS (r = 0.36, medium effect size). However, a stronger relationship was found between the blast-related variables and three modified GBEV scores when excluding some small weapons categories; single-item LBE (rs = 0.80-0.82), CES (rs = 0.64-0.67), number of combat deployments (rs = 0.56), DRRI-2 CE (rs = 0.51-0.53), and high blast risk MOS (r = 0.42-0.49, medium-large effect size). This is the first study to examine the psychometric properties of the BETS. Overall, these results offer support for the convergent and discriminant validity of the BETS. In order to ensure that the BETS can be confidently used as a valid and reliable measure of LBE, more research is needed to further examine the psychometric properties of the test, particularly with regard to the establishment of test-retest reliability.

Gender Disparities in Neurobehavioral Symptoms and the Role of Post-Traumatic Symptoms in US Service Members Following Mild Traumatic Brain Injury.

Women are more directly involved in combat operations today than ever before, currently making up 18.6% of officers and 16.8% of enlisted personnel in the United States military. However, women continue to be under-represented in military research. Studies that do consider gender differences in traumatic brain injury (TBI) outcomes have shown that women report significantly more post-concussive symptoms than men. Conclusions for true gender differences related to TBI are hard to make without controlling for non-TBI factors. The effects previously identified in the literature may be an artifact of how men and women differ in their response to injury, unrelated to the neurological recovery process associated with TBI. The objective of this study was to examine the effects of gender specifics on mild TBI (mTBI) sequelae on injured and uninjured control groups, and to investigate the role of post-traumatic stress disorder (PTSD) on symptom reporting. It should be noted that the terms "gender" and "men/women" are used in this article in place of "sex" or "males/females" given that we are not discussing biological attributes. A total of 966 United States military service members and veterans were included in the study. Of the total sample, 455 men and 46 women were in the mTBI group, 285 men and 31 women were in the injured controls group (IC), and 111 men and 38 women in the non-injured controls group (NIC). Post-concussive and quality of life symptoms were compared for men and women while controlling for combat exposure. MTBI and IC groups were also stratified by PTSD presentation. Measures used included the Neurobehavioral Symptom Inventory (NSI), PTSD Checklist (PCL-C), Traumatic Brain Injury Quality of Life (TBI-QOL), and Combat Exposure Scale. In the mTBI group, women had worse scores on NSI total, NSI Somatosensory and Affective clusters, and the TBI-QOL Anxiety, Fatigue, and Headache scales (n2 = 0.018-0.032, small to small-medium effect sizes). When PTSD was present, women had worse scores on the NSI Somatosensory cluster only (n2 = 0.029, small-medium effect size). In contrast, when PTSD was absent, women had worse scores than men on the NSI Somatosensory and Affective clusters, and the TBI-QOL Anxiety and Headache scales (n2 = 0.032-0.063, small to medium effect sizes). In the IC group, women had worse scores on the NSI Cognitive cluster and the TBI-QOL Fatigue and Pain Interference scales (n2 = 0.024-0.042, small to small-medium effect sizes). However, group differences were no longer found when stratified by PTSD sub-groups. In the NIC group, there were no significant group differences for any analyses. We were able to identify symptoms unique to women recovering from mTBI that were not present following other forms of physical injury or in healthy controls. However, the impact of PTSD exacerbates the symptom profile and its comorbidity with mTBI equates to most of the noted gender differences.

The Patient Global Impression of Change as a complementary tool to account for neurobehavioral and mental health symptom improvement for patients with concussion.

PURPOSE: The purpose of this study was to determine the extent to which patient's perspective of symptom improvement, as indexed by the Patient Global Impression of Change (PGIC) survey, is associated with symptom improvement on common measures of neurobehavioral and mental health symptoms following concussion. MATERIALS AND METHODS: Data were from 449 US active duty service members receiving treatment in interdisciplinary programs for their concussion. PGIC rating (range = 1-7) was evaluated for compatibility in assessing improvement in or clinically-elevated neurobehavioral (using Neurobehavioral Symptom Inventory [NSI]) and mental health (using Post-traumatic Stress Disorder Checklist, DSM-5 [PCL-5] and Patient Health Questionnaire [PHQ-8]) symptoms. RESULTS: Higher PGIC scores were related to a higher prevalence of clinically-relevant decrease in NSI, PCL-5 or PHQ-8 scores. Participants with a PGIC rating of 3+ (vs.<3) were about 2.2 (CI = 1.4-3.5), 1.6 (CI = 1.1-1.3), and 2.7 (CI = 1.4-5.1) times more likely to report clinically-relevant decrease in NSI, PCL-5 and PHQ-8 symptoms, respectively. CONCLUSION: PGIC may help providers incorporate patients' perspectives on symptom improvement achieved during rehabilitation. An approach combining PGIC with surveys such as NSI, PCL-5 and PHQ-8 may provide a more comprehensive understanding of symptom improvement and realistic view of expectations for what would be deemed recovery to pre-injury symptom levels.

Concussion significantly impacts cognitive, physical and mental health, and active duty service members (SMs) are at high risk due to their occupation demands.The Patient Global Impression of Change (PGIC) assesses symptom improvement, as perceived by the patient, which may align better with usual/pre-injury level symptoms prior to injury compared to other common measures of neurobehavioral and mental health symptoms for concussion patients.A comprehensive approach in which PGIC is included in symptom assessment may provide a better understanding of symptom improvement and provide a more realistic view of expectations for what would be deemed recovery to usual/pre-injury level or improvement in symptoms.

High Lifetime Blast Exposure Using the Blast Exposure Threshold Survey Is Associated With Worse Warfighter Brain Health Following Mild Traumatic Brain Injury.

The purpose of this study was to extend previous research by examining the relationship between lifetime blast exposure and neurobehavioral functioning after mild TBI (MTBI) by (a) using a comprehensive measure of lifetime blast exposure, and (b) controlling for the influence of post-traumatic stress disorder (PTSD). Participants were 103 United States service members and veterans (SMVs) with a medically documented diagnosis of MTBI, recruited from three military treatment facilities (74.8%) and community-based recruitment initiatives (25.2%, e.g., social media, flyers). Participants completed a battery of neurobehavioral measures 12 or more months post-injury (Neurobehavioral Symptom Inventory, PTSD-Checklist PCLC, TBI-Quality of Life), including the Blast Exposure Threshold Survey (BETS). The sample was classified into two lifetime blast exposure (LBE) groups: High (n = 57) and Low (n = 46) LBE. In addition, the sample was classified into four LBE/PTSD subgroups: High PTSD/High LBE (n = 38); High PTSD/Low LBE (n = 19); Low PTSD/High LBE (n = 19); and Low PTSD/Low LBE (n = 27). The High LBE group had consistently worse scores on all neurobehavioral measures compared with the Low LBE group. When controlling for the influence of PTSD (using ANCOVA), however, only a handful of group differences remained. When comparing measures across the four LBE/PTSD subgroups, in the absence of clinically meaningful PTSD symptoms (i.e., Low PTSD), participants with High LBE had worse scores on the majority of neurobehavioral measures (e.g., post-concussion symptoms, sleep, fatigue). When examining the total number of clinically elevated measures, the High LBE subgroup consistently had a greater number of clinically elevated scores compared with the Low LBE subgroup for the majority of comparisons (i.e., four to 15 or more elevated symptoms). In contrast, in the presence of clinically meaningful PTSD symptoms (i.e., High PTSD), there were no differences between High versus Low LBE subgroups for all measures. When examining the total number of clinically elevated measures, however, there were meaningful differences between High versus Low LBE subgroups for those comparisons that included a high number of clinically elevated scores (i.e., six to 10 or more), but not for a low number of clinically elevated scores (i.e., one to five or more). High LBE, as quantified using a more comprehensive measure than utilized in past research (i.e., BETS), was associated with worse overall neurobehavioral functioning after MTBI. This study extends existing literature showing that lifetime blast exposure, that is largely subconcussive, may negatively impact warfighter brain health and readiness beyond diagnosable brain injury.

Service needs and neurobehavioral functioning following traumatic brain injury in U.S. military personnel.

OBJECTIVE: The purpose of this study was to (a) identify the prevalence and barriers of self-reported service needs in a military sample with and without traumatic brain injury (TBI), (b) evaluate the influence of the number of service needs on overall neurobehavioral functioning, and (c) examine the longitudinal trajectories of service needs over time. METHOD: Participants were 941 U.S. service members and veterans (SMVs) prospectively enrolled into four groups: uncomplicated mild TBI (MTBI; n = 455); complicated mild, moderate, severe, and penetrating TBI combined (STBI; n = 164); injured controls (IC, n = 138); and noninjured controls (NIC, n = 184). Participants completed a battery of neurobehavioral measures, as well as a self-reported service need interview, 12 or more month's postinjury. In addition, a longitudinal cohort (n = 553) was included using a subset of participants who had completed two or more evaluations. RESULTS: When examining the total number of self-reported service needs, there was a greater proportion of the MTBI and STBI groups that had a higher number of service needs compared to the NIC and IC groups (p < .001). In the MTBI and STBI groups, as the number of service needs increased, worse scores were found on all neurobehavioral measures. In the longitudinal cohort, the STBI group reported the highest number of service needs that persisted or developed over time (six needs), followed by the MTBI (three needs), IC (one need), and NIC (zero need) groups. CONCLUSIONS: These findings call for the need to enhance the provision of information given to service members and veterans following TBI regarding available services. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Clinical relevance of subthreshold PTSD versus full criteria PTSD following traumatic brain injury in U.S. service members and veterans.

BACKGROUND: The purpose of this cross-sectional study was to examine the influence of subthreshold posttraumatic stress disorder (PTSD) and full PTSD on quality of life following mild traumatic brain injury (mTBI). METHODS: Participants were 734 service members and veterans (SMV) classified into two injury groups: uncomplicated mild TBI (MTBI; n = 596) and injured controls (IC, n = 139). Participants completed a battery of neurobehavioral measures, 12-or-more months post-injury, that included the PTSD Checklist Civilian version, Neurobehavioral Symptom Inventory, and select scales from the TBI-QOL and MPAI. The MTBI group was divided into three PTSD subgroups: No-PTSD (n = 266), Subthreshold PTSD (n = 139), and Full-PTSD (n = 190). RESULTS: There was a linear relationship between PTSD severity and neurobehavioral functioning/quality of life in the MTBI sample. As PTSD severity increased, significantly worse scores were found on 11 of the 12 measures (i.e. , MTBI: Full-PTSD > Sub-PTSD > No-PTSD). When considering the number of clinically elevated scores, a linear relationship between PTSD severity and neurobehavioral functioning/quality of life was again observed in the MTBI sample (e.g., 3-or-more elevated scores: Full-PTSD = 92.1 %, Sub-PTSD = 61.9 %, No-PTSD = 19.9 %). LIMITATIONS: Limitations included the use of a self-report measure to determine diagnostic status that may under/overcount or mischaracterize individuals. CONCLUSION: PTSD symptoms, whether at the level of diagnosable PTSD, or falling short of that because of the intensity or characterization of symptoms, have a significant negative impact on one's quality of life following MTBI. Clinicians' treatment targets should focus on the symptoms that are most troubling for an individual and the individual's perception of quality of life, regardless of the diagnosis itself.

The Impact of Lifetime Traumatic Brain Injury (TBI) on Mental Health Symptoms among Service Members in Interdisciplinary TBI Programs.

INTRODUCTION: Traumatic brain injury (TBI) is highly prevalent among active duty service members (ADSMs) and imposes a significant health burden, particularly on mental health (e.g., post-traumatic stress disorder [PTSD] and depressive symptoms). Little is known about how TBI setting characteristics impact PTSD and depressive symptom expression in service members undergoing interdisciplinary TBI care. MATERIALS AND METHODS: The study included 455 patients enrolled in interdisciplinary, outpatient TBI programs within the military health system. Using Poisson regression with robust error variance, TBI injury setting characteristics (i.e., before military service, during military training, and during noncombat/combat deployment) were evaluated against clinically-elevated PTSD (PTSD Checklist, DSM-5 score ≥ 33) and depressive (Patient Health Questionnaire-8 score ≥ 15) symptoms. RESULTS: In adjusted models, TBI sustained before military service was associated with less likelihood for clinically-elevated PTSD symptoms at pretreatment (prevalence ratio [PR] = 0.76, confidence interval [CI] = 0.60-0.96) and post-treatment (PR = 0.67, CI = 0.52-0.87). TBI sustained during combat deployment, however, resulted in the greatest impact on clinically-elevated pretreatment PTSD (PR = 1.49, CI = 1.16-1.91) and depressive (PR = 1.47, CI = 1.06-2.03) symptoms. Null results were found between military training/noncombat deployment and mental health symptoms. Regardless of the TBI setting, following TBI treatment, there remained 37.5% (n = 180) and 24.8% (n = 108) with clinically-elevated PTSD and depressive symptoms, respectively. CONCLUSIONS: There was a differential impact of TBI settings, particularly between TBI sustained before military service and that from combat deployment among ADSMs enrolled in outpatient TBI programs. This may be indicative of differences in the characteristics of these environments (e.g., injury severity) or the impact of such an event during recovery from current TBIs. The large percentage of ADSMs who present with clinically-elevated mental health symptoms after treatment may suggest the need for additional resources to address mental health needs before, during, and after treatment in TBI programs.

Associations of mTBI and post-traumatic stress to amygdala structure and functional connectivity in military Service Members.

Introduction: Traumatic brain injury (TBI) is one of the highest public health priorities, especially among military personnel where comorbidity with post-traumatic stress symptoms and resulting consequences is high. Brain injury and post-traumatic stress symptoms are both characterized by dysfunctional brain networks, with the amygdala specifically implicated as a region with both structural and functional abnormalities. Methods: This study examined the structural volumetrics and resting state functional connectivity of 68 Active Duty Service Members with or without chronic mild TBI (mTBI) and comorbid symptoms of Post-Traumatic Stress (PTS). Results and discussion: Structural analysis of the amygdala revealed no significant differences in volume between mTBI and healthy comparison participants with and without post-traumatic stress symptoms. Resting state functional connectivity with bilateral amygdala revealed decreased anterior network connectivity and increased posterior network connectivity in the mTBI group compared to the healthy comparison group. Within the mTBI group, there were significant regions of correlation with amygdala that were modulated by PTS severity, including networks implicated in emotional processing and executive functioning. An examination of a priori regions of amygdala connectivity in the default mode network, task positive network, and subcortical structures showed interacting influences of TBI and PTS, only between right amygdala and right putamen. These results suggest that mTBI and PTS are associated with hypo-frontal and hyper-posterior amygdala connectivity. Additionally, comorbidity of these conditions appears to compound these neural activity patterns. PTS in mTBI may change neural resource recruitment for information processing between the amygdala and other brain regions and networks, not only during emotional processing, but also at rest.

Disparities in mental health symptoms recovery across race/ethnicity and education level following mild traumatic brain injury.

Purpose: The purpose of this study was to investigate the relationship between race/ethnicity and post-concussive mental health (i.e., depressive, post-traumatic stress disorder [PTSD]) and neurobehavioral symptoms among service members, and whether this association differed by education level. Methods: The study sample consisted of 524 patients from a multidisciplinary US military outpatient treatment facility for post-concussive symptoms. Poisson regression with robust error variance was utilized to investigate outcome (i.e., clinically-elevated depressive [Patient Health Questionnaire-8 ≥15], PTSD [PTSD Checklist, DSM 5 ≥38] and neurobehavioral [Neurobehavioral Symptom Inventory >75th percentile] symptoms at admission and last follow-up in this cohort study. Modification by education level (low [no college degree] vs. high [associate's degree or higher]) was additionally evaluated. Results: The relationship between race/ethnicity and mental health/neurobehavioral symptoms varied by education level (p-interaction: depressive symptoms = 0.002, PTSD symptoms = 0.035, neurobehavioral symptoms = 0.040). Specifically, non-Whites were at a significantly higher prevalence for clinically-elevated depressive symptoms post-treatment than Whites, but only among those with higher education level (PR = 2.22, CI = 1.37-3.59). A similar trend was demonstrated for PTSD and neurobehavioral symptoms. Conclusion: Military healthcare may need to increase depression-focused treatment options that are acceptable for racial/ethnic minority patients, particularly those with higher education, while they are recovering from comorbid traumatic brain injury.