Low resilience is associated with worse health-related quality of life in caregivers of service members and veterans with traumatic brain injury: a longitudinal study.

PURPOSE: To examine [a] the association of caregiver health-related quality of life (HRQOL) and service member/veteran (SMV) neurobehavioral outcomes with caregiver resilience; [b] longitudinal change in resilience at the group and individual level; and [c] the magnitude of change at the individual level. METHODS: Caregivers (N = 232) of SMVs with traumatic brain injury completed a resilience measure, and 18 caregiver HRQOL and SMV neurobehavioral outcome measures at a baseline evaluation and follow-up evaluation three years later. Caregivers were divided into two resilience groups at baseline and follow-up: [1] Low Resilience (≤ 45 T, baseline n = 99, follow-up n = 93) and [2] High Resilience (> 45 T, baseline n = 133, follow-up n = 139). RESULTS: At baseline and follow-up, significant effects were found between Low and High Resilience groups for the majority of outcome measures. There were no significant differences in resilience from baseline to follow-up at the group-mean level. At the individual level, caregivers were classified into four longitudinal resilience groups: [1] Persistently Low Resilience (Baseline + Follow-up = Low Resilience, n = 60), [2] Reduced Resilience (Baseline = High Resilience + Follow-up = Low Resilience, n = 33), [3] Improved Resilience (Baseline = Low Resilience + Follow-up = High Resilience, n = 39), and [4] Persistently High Resilience (Baseline + Follow-up = High Resilience, n = 100). From baseline to follow-up, approximately a third of the Reduced and Improved Resilience groups reported a meaningful change in resilience (≥ 10 T). Nearly all of the Persistently High and Persistently Low Resilience groups did not report meaningful change in resilience (< 10 T). CONCLUSION: Resilience was not a fixed state for all caregivers. Early intervention may stall the negative caregiving stress-health trajectory and improve caregiver resilience.

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.

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.

Lifetime blast exposure is not related to cognitive performance or psychiatric symptoms in US military personnel.

Objective: The present study aimed to examine the impact of lifetime blast exposure (LBE) on neuropsychological functioning in service members and veterans (SMVs). Method: Participants were 282 SMVs, with and without history of traumatic brain injury (TBI), who were prospectively enrolled in a Defense and Veterans Brain Injury Center (DVBIC)-Traumatic Brain Injury Center of Excellence (TBICoE) Longitudinal TBI Study. A cross-sectional analysis of baseline data was conducted. LBE was based on two factors: Military Occupational Speciality (MOS) and SMV self-report. Participants were divided into three groups based on LBE: Blast Naive (n = 61), Blast + Low Risk MOS (n = 96), Blast + High Risk MOS (n = 125). Multivariate analysis of variance (MANOVA) was used to examine group differences on neurocognitive domains and the Minnesota Multiphasic Personality Inventory-2 Restructured Form. Results: There were no statistically significant differences in attention/working memory, processing speed, executive functioning, and memory (Fs < 1.75, ps > .1, ηp2s < .032) or in General Cognition (Fs < 0.95, ps > .3, ηp2s < .008). Prior to correction for covariates, lifetime blast exposure was related to Restructured Clinical (F(18,542) = 1.77, p = .026, ηp2 = .055), Somatic/Cognitive (F(10,550) = 1.99, p = .033, ηp2 = .035), and Externalizing Scales (F(8,552) = 2.17, p = .028, ηp2 = .030); however, these relationships did not remain significant after correction for covariates (Fs < 1.53, ps > .145, ηp2s < .032). Conclusions: We did not find evidence of a relationship between LBE and neurocognitive performance or psychiatric symptoms. This stands in contrast to prior studies demonstrating an association between lifetime blast exposure and highly sensitive blood biomarkers and/or neuroimaging. Overall, findings suggest the neuropsychological impact of lifetime blast exposure is minimal in individuals remaining in or recently retired from military service.

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.

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.

Longitudinal health outcomes in caregivers of military members with traumatic brain injury.

PURPOSE/OBJECTIVE: To examine longitudinal change in health-related quality of life (HRQOL) in caregivers of service members/veterans with traumatic brain injury and factors associated with clinically elevated symptoms. RESEARCH METHOD/DESIGN: Caregivers (N = 220) completed nine HRQOL outcome measures and 10 risk factor measures at a baseline evaluation and follow-up evaluation 3 years later. Caregiver's responses on the nine HRQOL outcome measures were classified into four clinical change categories based on the presence/absence of clinically elevated T-scores (≥ 60 T) at baseline and follow-up: (a) Persistent (baseline ≥ 60T + follow-up ≥ 60 T), (b) Developed (baseline < 60 T + follow-up ≥ 60 T), (c) Improved (baseline ≥ 60 T + follow-up < 60 T), and (d) Asymptomatic (baseline < 60 T + follow-up < 60 T). A clinical change composite score was calculated by summing the number of Persistent or Developed HRQOL outcome measures and used to create three clinical change groups: (a) No Symptoms (n = 69, zero measures), (b) Some Symptoms (n = 88, one to three measures), and (c) Numerous Symptoms (n = 63, four to nine measures). RESULTS: Of the nine HRQOL outcome measures, Bodily Pain, Perceived Stress, Sleep-Related Impairment, and Fatigue were most frequently classified as Persistent or Developed from baseline to follow-up in the entire sample. A linear relationship was found between the vast majority of risk factors across the three clinical change groups at baseline and follow-up (Numerous > Some > None). The risk factors were correlated with the number of elevated HRQOL symptoms at baseline and follow-up. Most Asymptomatic or Persistent caregivers did not have meaningful change (≥ 1 SD) in HRQOL scores. A sizable proportion of Developed or Improved caregivers had either meaningful or no change in HRQOL scores. CONCLUSIONS/IMPLICATIONS: There is a need for ongoing clinical services for military caregivers. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Lifetime Blast Exposure Is Not Related to White Matter Integrity in Service Members and Veterans With and Without Uncomplicated Mild Traumatic Brain Injury.

This study examines the impact of lifetime blast exposure on white matter integrity in service members and veterans (SMVs). Participants were 227 SMVs, including those with a history of mild traumatic brain injury (mTBI; n = 124), orthopedic injury controls (n = 58), and non-injured controls (n = 45), prospectively enrolled in a Defense and Veterans Brain Injury Center (DVBIC)/Traumatic Brain Injury Center of Excellence (TBICoE) study. Participants were divided into three groups based on number of self-reported lifetime blast exposures: none (n = 53); low (i.e., 1-9 blasts; n = 81); and high (i.e., ≥10 blasts; n = 93). All participants underwent diffusion tensor imaging (DTI) at least 11 months post-injury. Tract-of-interest (TOI) analysis was applied to investigate fractional anisotropy and mean, radial, and axial diffusivity (AD) in left and right total cerebral white matter as well as 24 tracts. Benjamini-Hochberg false discovery rate (FDR) correction was used. Regressions investigating blast exposure and mTBI on white matter integrity, controlling for age, revealed that the presence of mTBI history was associated with lower AD in the bilateral superior longitudinal fasciculus and arcuate fasciculus and left cingulum (ßs = -0.255 to -0.174; ps < 0.01); however, when non-injured controls were removed from the sample (but orthopedic injury controls remained), these relationships were attenuated and did not survive FDR correction. Regression models were rerun with modified post-traumatic stress disorder (PTSD) diagnosis added as a predictor. After FDR correction, PTSD was not significantly associated with white matter integrity in any of the models. Overall, there was no relationship between white matter integrity and self-reported lifetime blast exposure or PTSD.

Longitudinal health-related quality of life in military caregivers no longer providing care.

PURPOSE/OBJECTIVE: To examine health-related quality of life (HRQOL) in caregivers when providing care and no longer providing care to service members/veterans with traumatic brain injury. RESEARCH METHOD/DESIGN: Participants included 466 caregivers enrolled in a 15-year longitudinal study. During an annual follow-up evaluation, a subsample of caregivers self-identified as no longer providing care and were retained in the study as a No Longer Caregiving group (n = 48). Scores on HRQOL measures when providing care (baseline) and no longer providing care (follow-up) were examined. Scores on HRQOL measures were also compared with the remaining 418 caregivers (Caregiving group). RESULTS: The most frequent reasons for no longer caregiving were no longer being in a relationship with the SMV and the SMV had recovered/no longer required care. The No Longer Caregiving group at follow-up reported better scores on five measures compared to baseline, and three measures compared to the Caregiving group. There were no differences in the proportion of clinically elevated scores on HRQOL measures for the No Longer Caregiving group between baseline and follow-up. Compared to the Caregiving group, the No Longer Caregiving group reported a higher prevalence of clinical elevated scores on General Life Satisfaction at baseline and follow-up, and worse scores on Caregiving Relationship Satisfaction and the Couples Satisfaction Index at baseline. CONCLUSIONS/IMPLICATIONS: While some improvement in HRQOL was noted when caregivers were no longer providing care, many continued to report elevated scores. Services and supports are required for caregivers when providing care, but also when transitioning out of a caregiving role. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Health outcomes in caregivers of service members and veterans with traumatic brain injury enrolled in the U.S. Veterans Affairs Caregiver Support Program.

To explore health outcomes in caregivers of service members and veterans (SMV) with traumatic brain injury (TBI) enrolled in two programs within the U.S. Department of Veterans Affairs (VA) Caregiver Support Program (CSP) (General and Comprehensive Programs) and those not enrolled. Participants were 290 caregivers classified into three groups: (a) General Program (n = 34); (b) Comprehensive Program (n = 104); and (c) Not Enrolled (n = 152). Main outcome measures assessed caregiver health-related quality of life (HRQOL), SMV functional ability, and caregiver needs. Compared to the Not Enrolled group, the General, and Comprehensive Program groups reported worse scores on five of 25 caregiver HRQOL measures and had a higher proportion of elevated scores on two measures. The Comprehensive Program group reported worse scores on an additional seven HRQOL measures and a higher proportion of elevated scores on three measures compared to the Not Enrolled group. Over 20% of caregivers in each group reported clinically elevated scores on eight HRQOL measures. Few differences between caregiver groups were identified for unmet needs. In the total sample, eight HRQOL measures consistently emerged that were more strongly associated with caregiver needs. Caregivers enrolled in the VA CSP tended to report worse HRQOL and caring for a SMV with worse functional ability compared to those not enrolled. A better understanding of health care utilization for those not enrolled in the CSP and in need of help is required. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Health outcomes before and during the COVID-19 pandemic in caregivers of service members and veterans with traumatic brain injury.

PURPOSE: To examine change in health-related quality of life (HRQOL) during the COVID-19 pandemic in caregivers of service members/veterans (SMVs) with traumatic brain injury (TBI), by comparing HRQOL during the first year of the pandemic to HRQOL 12 months pre-pandemic. METHODS: Caregivers (N = 246) were classified into three COVID-19 Pandemic Impact groups based on impact ratings of the pandemic on HRQOL: No Impact (n = 50), Mild Impact (n = 117), and Moderate-Severe Impact (n = 79). Caregivers completed 19 measures across physical, social, caregiving, and economic HRQOL domains, and a measure of SMV Adjustment. T-scores were used to determine individual symptom trajectories for each measure as follows: Asymptomatic (pre + during < 60 T); Developed (pre < 60 + during ≥ 60 T); Improved (pre ≥ 60 T + during < 60 T); and Persistent (pre + during ≥ 60 T). RESULTS: Using ANOVA, during the pandemic, the Moderate-Severe Impact group reported worse scores on 19 measures (d = 0.41-0.89) compared to the No Impact group and 18 measures (d = 0.31-0.62) compared to the Mild Impact group (d = 0.31-0.38). The Mild Impact group reported worse scores on two measures compared to the No Impact group (d = 0.42-0.43). Using the entire sample, the majority of HRQOL measures were classified as Asymptomatic (47.2-94.7%), followed by Persistent (2.4-27.2%). Few were classified as Developed (0.4-12.6%) or Improved (2.4-13.8%). Using repeated measures ANOVA, no meaningful effects sizes were found for mean scores on all measures completed pre-pandemic compared to during the pandemic (d ≤ 0.17). CONCLUSION: The vast majority of caregivers reported stability in HRQOL pre-pandemic compared to during the pandemic. The COVID-19 pandemic was not associated with a high prevalence of decline in caregiver HRQOL.

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.

Efficient Estimation of the Binaural Masking Level Difference Using a Technique Based on Manual Audiometry.

PURPOSE: The Masking Level Difference (MLD) has been used for decades to evaluate the binaural listening advantage. Although originally measured using Bekesy audiometry, the most common clinical use of the MLD is the CD-based Wilson 500-Hz technique with interleaved N0S0 and N0Sπ components. Here, we propose an alternative technique based on manual audiometry as a faster way of measuring the MLD. The article describes the advantages to this administration technique and evaluates if it is a viable alternative for the Wilson technique. METHOD: Data were retrospectively analyzed on 264 service members (SMs). All SMs completed both the Wilson and Manual MLDs. Descriptive and correlational statistics were applied to evaluate the comparisons between the two techniques and highlight the differences. Equivalence measures were also completed to compare the tests using a standardized cutoff score. Analyses were also made to compare both techniques to subjective and objective measures of hearing performance. RESULTS: Moderate to high positive correlations were determined between Wilson and Manual measures of each threshold (N0Sπ and N0S0). Although the Manual and Wilson MLD techniques produced significantly different thresholds, simple linear transformations can be used to obtain approximately equivalent scores on the two tests, and agreement was high for using these transformed scores to identify individuals with substantial MLD deficits. Both techniques had moderate test-retest reliability. The Manual MLD and components had stronger correlations to the subjective and objective hearing measures than the Wilson. CONCLUSIONS: The Manual technique is a faster method for obtaining MLD scores that is just as reliable as the CD-based Wilson test. With the significant reduction in assessment time and comparable results, the Manual MLD is a viable alternative for direct use in the clinic.

Normative Ranges for, and Interrater Reliability of, Rotational Vestibular and Balance Tests in U.S. Military Service Members and Veterans.

PURPOSE: The objectives of this study were to (a) describe normative ranges-expressed as reference intervals (RIs)-for vestibular and balance function tests in a cohort of Service Members and Veterans (SMVs) and (b) to describe the interrater reliability of these tests. METHOD: As part of the Defense and Veterans Brain Injury Center (DVBIC)/Traumatic Brain Injury Center of Excellence 15-year Longitudinal Traumatic Brain Injury (TBI) Study, participants completed the following: vestibulo-ocular reflex suppression, visual-vestibular enhancement, subjective visual vertical, subjective visual horizontal, sinusoidal harmonic acceleration, the computerized rotational head impulse test (crHIT), and the sensory organization test. RIs were calculated using nonparametric methods and interrater reliability was assessed using intraclass correlation coefficients between three audiologists who independently reviewed and cleaned the data. RESULTS: Reference populations for each outcome measure comprised 40 to 72 individuals, 19 to 61 years of age, who served either as noninjured controls (NIC) or injured controls (IC) in the 15-year study; none had a history of TBI or blast exposure. A subset of 15 SMVs from the NIC, IC, and TBI groups were included in the interrater reliability calculations. RIs are reported for 27 outcome measures from the seven rotational vestibular and balance tests. Interrater reliability was considered excellent for all tests except the crHIT, which was found to have good interrater reliability. CONCLUSION: This study provides clinicians and scientists with important information regarding normative ranges and interrater reliability for rotational vestibular and balance tests in SMVs.

Cross-Walk Comparison of the DVBIC-TBICoE and LIMBIC-CENC Combat-Related Concussion Prospective Longitudinal Study Datasets.

OBJECTIVE: To describe and compare cohorts between 2 large, longitudinal, federally-funded TBI studies of Service members and veterans across demographic, self-report, and neuropsychological variables. DESIGN: Analysis of data from the DVBIC-TBICoE and LIMBIC-CENC prospective longitudinal studies (PLS). SETTING: Recruitment locations spanning Department of Defense and Veterans Affairs hospitals across the U.S. PARTICIPANTS: 1463 participants (N=1463) enrolled in the DVBIC-TBICoE study and divided among non-injured (NIC) (n=191), injured control (IC) (n=349), mild TBI (mTBI) (n=682), and (severe, moderate, penetrating, and complicated mild traumatic brain injury (smcTBI) (n=241) subgroups. 1550 participants enrolled in the LIMBIC-CENC study and divided between IC (n=285) and mTBI (n=1265) subgroups. IC and mTBI study groups were compared across demographic and military characteristics, self-reported symptoms, and neuropsychological test scores. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Neurobehavioral Symptom Inventory, PTSD Checklist-Military Version, TBI quality of life, Test of Premorbid Functioning, Wechsler Adult Intelligence Scale-IV Visual Puzzles, Symbol Search, Coding, Letter-Number Sequencing, and Digit Span, Trail Making Test, Delis-Kaplan Executive Functioning System Verbal Fluency, Letter Fluency, and Category Fluency, California Verbal Learning Test-II, and Grooved Pegboard. RESULTS: Compared with DVBIC-TBICoE, LIMBIC-CENC participants have higher enrollment age, education level, proportion of Black race, and time from injury as well as less combat deployments and are less likely to be married. The distribution of military service branches also differed. Further, symptom profiles differed between cohorts. LIMBIC-CENC participants endorsed higher posttraumatic stress disorder symptomatology. DVBIC-TBICoE study IC participants endorsed higher somatosensory and vestibular symptoms (medium effect sizes). Other symptom measure differences had very small effect sizes (≤0.2). Differences were found on many cognitive test results, but are difficult to interpret given the demographic differences and generally very small effect sizes. CONCLUSIONS: The heavy use of National Institutes of Health common data elements in both studies and collaboration with the DVBIC-TBICoE study team on development of the LIMBIC-CENC assessment battery enabled this comparative analysis. Results highlight unique differences in study cohorts and add perspective and interpretability for assimilating past and future findings.

White Matter Integrity Relates to Cognition in Service Members and Veterans after Complicated Mild, Moderate, and Severe Traumatic Brain Injury, But Not Uncomplicated Mild Traumatic Brain Injury.

The extant literature investigating the relationship between diffusion tensor imaging (DTI) and cognition following traumatic brain injury (TBI) is limited by small sample sizes and inappropriate control groups. The present study examined DTI metric differences between service members and veterans (SMVs) with bodily injury (Trauma Control; TC), uncomplicated mild TBI (mTBI), complicated mild TBI (compTBI), and severe-moderate TBI combined (smTBI), and how DTI metrics related to cognition within each group. Participants were 226 SMVs (56 TC, 112 mTBI, 29 compTBI, 29 smTBI) with valid neuropsychological testing and DTI at least 11 months post-injury. The smTBI group demonstrated decreased fractional anisotropy (FA) and increased axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) of the cerebral white matter (CWM) and several individual white matter tracts compared with the TC, mTBI, and compTBI groups (all ps < 0.05; rs = 0.17 to 0.49). The TC, mTBI, and compTBI groups did not differ in terms of any DTI metrics. Within the smTBI group, FA, AD, MD, and RD of the total CWM and several white matter tracts were related to Processing Speed (|rs|: 0.43 to 0.66; ps < 0.05), and/or Delayed Memory (|rs|: 0.41 to 0.67; ps < 0.05). In the compTBI group, Processing Speed was related to left arcuate fasciculus and superior longitudinal fasciculus (SLF) FA, MD, and RD, as well as left uncinate fasciculus MD and RD. In contrast, there were no significant relationships between DTI metrics and cognition/emotional functioning within the mTBI or TC groups. Overall, findings suggest a dose-response relationship between TBI severity and the strength of the relationship between white matter integrity and cognitive performance, with essentially no relationship in mTBI, some findings in compTBI, and several strongly significant relationships in smTBI. In contrast to previously reported findings, there were no differences in DTI metrics between controls, mTBI, and compTBI, and DTI metrics were unrelated to cognition in our relatively large mTBI group.

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.

Serum Tau, Neurofilament Light Chain, Glial Fibrillary Acidic Protein, and Ubiquitin Carboxyl-Terminal Hydrolase L1 Are Associated with the Chronic Deterioration of Neurobehavioral Symptoms after Traumatic Brain Injury.

The purpose of this study was to examine the association of serum tau, neurofilament light chain (NFL), glial fibrillary acidic protein (GFAP), and ubiquitin carboxy-terminal hydrolase L1 (UCHL-1) concentrations evaluated within the first 12 months after a military-related TBI, with longitudinal changes in neurobehavioral functioning extending two or more years post-injury. Participants were 84 United States service members and veterans (SMVs) prospectively enrolled in the Defense and Veterans Brain Injury Center of Excellence/Traumatic Brain Injury Center 15-Year Longitudinal TBI Study, separated into three discreet groups: (a) uncomplicated mild TBI (MTBI; n = 28), (b) complicated mild, moderate, severe, and penetrating TBI combined (STBI; n = 29], and (c) non-injured controls (NIC, n = 27). Participants completed a battery of self-report neurobehavioral symptom measures (e.g., depression, post-traumatic stress disorder [PTSD], post-concussion, anxiety, somatic, cognitive, and neurological symptoms) within 12 months of injury (baseline), and then again at two or more years post-injury (follow-up). At baseline, participants also completed a blood draw to determine serum concentrations of tau, NFL, GFAP, and UCHL-1 using an ultra-sensitivity assay method. In the MTBI and STBI groups (using hierarchical regression analyses), (1) baseline tau concentrations predicted the deterioration of neurobehavioral symptoms from baseline to follow-up on measures of anxiety, PTSD, depression, post-concussion, somatic, and neurological symptoms (accounting for 10-28% of the variance); (2) NFL predicted the deterioration of depression, post-concussion, somatic, cognitive, and neurological symptoms (10-32% variance); (3) GFAP predicted the deterioration of post-concussion, PTSD, depression, anxiety, somatic, neurological, and cognitive symptoms (11-43% variance); and (4) UCHL-1 predicted the deterioration of anxiety, somatic, and neurological symptoms (10-16% variance). In the NIC group, no meaningful associations were found between baseline biomarker concentrations and the deterioration of neurobehavioral symptoms on the majority of measures. This study reports that elevated tau, NFL, GFAP, and UCHL-1 concentrations within the first 12 months of injury are associated with the deterioration of neurobehavioral symptoms that extends to the chronic phase of recovery after a TBI. These findings suggest that a blood-based panel including these biomarkers could be a useful prognostic tool to identifying those individuals at risk of poor future outcome after TBI.