The Structure of Postconcussion Symptoms on the Neurobehavioral Symptom Inventory: A Comparison of Alternative Models

Endophenotype presentation of athletes with concussion contingent on sex and time since injury

INTRODUCTION

Athletes with concussions experience heterogeneous symptoms and clinical trajectories. Subclassification provides diagnostic clarity that may improve prognostication and individualized treatments.

METHODS

We hypothesized that endophenotypes of adolescent athletes with concussions differ based on sex and time since injury. Post-concussive testing was performed for athletes (n = 1385) in the North Texas Concussion Registry (ConTex) at four timepoints: acute [0-3 days post-injury (DPI)], subacute-early (4-7DPI), subacute-late (8-28DPI), and persistent (29+DPI). Six endophenotypes (cognitive, headache, ocular-motor, vestibular, affective, sleep) were constructed by allocating post-concussion testing data elements described by the Concussion Subtype Workgroup.

RESULTS

Endophenotypes were defined using correlations between data elements and compared based on sex or time since injury. Correlograms revealed endophenotypes differed based on sex and time since injury. The affective endophenotype was dependent on the interaction between sex and time since injury and was more prevalent at the subacute-late and persistent timepoints. The sleep endophenotype became more prevalent at the persistent timepoint. Affective and sleep endophenotypes were interrelated with cognitive, vestibular, and headache endophenotypes at the persistent timepoint suggesting that dysregulated mood and sleep influence lingering symptoms.

CONCLUSIONS

Adolescent symptom-based concussion endophenotypes differ based on sex and time since injury. Clinical consideration may improve identification of separate trajectories following sport-related concussion and provide targeted care.

Neurocognitive Intraindividual Variability in Veterans with Mild Traumatic Brain Injury History and Posttraumatic Stress Disorder

OBJECTIVE

Veterans with a history of blast-related mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) may be at risk for greater cognitive concerns and worse functional outcomes compared to those with either condition in isolation. However, traditional neuropsychological assessment approaches have yielded equivocal results in these populations. The present study examined an alternative method for detecting subtle cognitive inefficiencies: neurocognitive intraindividual variability (IIV), a measure of within-person performance consistency.

METHOD

Participants were 79 male Veterans with a history of blast-related mTBI and current PTSD (mTBI/PTSD group; n = 54) or neither diagnosis (controls; n = 25). Mean T-scores and IIV scores were calculated from neuropsychological measures of attention and speed of information processing (A/SoP) as well as executive functioning (EF).

RESULTS

Global IIV was significantly higher in the mTBI/PTSD group compared to controls (p = .047, Cohen's d = 0.49). At the domain level, larger effect sizes were observed for EF IIV (Cohen's d = 0.46) compared to A/SoP IIV (d = 0.32), although neither were statistically significant. Within the mTBI/PTSD group, higher Global IIV was associated with worse self-reported executive dysfunction, psychological quality of life, and cognitive post-concussive symptoms; at the domain level, these clinical outcomes were generally associated with greater A/SoP IIV (but not EF IIV).

CONCLUSION

Findings extend previous investigations of neurocognitive IIV in individuals with a history of mTBI across PTSD status. Among Veterans with a history of mTBI and comorbid PTSD, neurocognitive variability may be a better indicator of self-reported cognitive inefficiencies and Veteran experience of daily cognitive functioning than mean neuropsychological performances.

Validation of Strategic Memory Advanced Reasoning Training as an efficient and effective approach to treating warfighters with persistent cognitive complaints associated with mild traumatic brain injury

Introduction

This study directly compared the relative effectiveness of Strategic Memory Advanced Reasoning Training (SMART), which focuses on metacognitive strategies, to a traditional cognitive rehabilitation (CR) program previously developed and validated for the Study of Cognitive Rehabilitation Effectiveness study (SCORE), in treating warfighters with a history of mild traumatic brain injury (mTBI) and persistent post-concussive symptoms (PCS).

Methods

A total of 148 active-duty service members (SMs) were recruited for this randomized controlled trial (RCT). Participants were randomly assigned to either the SMART (n = 80) or SCORE (n = 68) intervention arms. Outcome measures were administered at the start (T1) and end of treatment (T2), and at 3 months post-treatment (T3). Only participants with data from all timepoints and adequate performance validity (SMART: n = 51; SCORE: n = 43) were used in analyses. The primary outcome measure was the Global Deficit Scale (GDS), a composite of seven different objective measures of cognitive performance. Secondarily, participants completed the Neurobehavioral Symptom Inventory (NSI) and Key Behaviors Change Inventory (KBCI) self-report measures of post concussive symptoms (PCS). Lastly, a cost effectiveness analysis (CEA) was performed directly comparing the relative efficiencies of the two CR interventions.

Results

Mixed Analysis of Variance (ANOVA) showed a significant decrease in GDS scores from T1 to T3 (p < 0.001, ηp 2 = 0.217), irrespective of intervention type (p = 0.986, ηp 2 = 0.000). The greatest improvement occurred between T1 (SMART: M = 0.70, SD = 0.79; SCORE: M = 0.70, SD = 0.72) and T2 (SMART: M = 0.29, SD = 0.58; SCORE: M = 0.29, SD = 0.40), with scores plateauing at T3 (SMART: M = 0.28, SD = 0.52; SCORE: M = 0.29, SD = 0.57). Similarly, there was a significant decrease in NSI scores over the same period (p < 0.001, ηp 2 = 0.138), regardless of intervention type (p = 0.412, ηp 2 = 0.010). Additionally, treatment improved patient perceived functionality (KBCI) from T1 to T2 and these gains remained stable at T3 (p < 0.001, ηp 2 = 0.377). CEA revealed SMART represented a 60% reduction in cost compared to SCORE.

Discussion

This study demonstrates that SMART is an effective strategy for reducing cognitive deficits and PCS in SMs with a history of mTBI, producing comparable outcomes to a traditional CR program in less time and with improved cost efficiencies.

Relationships Between Neighborhood Disadvantage, Race/Ethnicity, and Neurobehavioral Symptoms Among Veterans With Mild Traumatic Brain Injury

OBJECTIVE

To examine the relationship between neighborhood disadvantage and severity of vestibular, sensory, mood-behavioral, and cognitive neurobehavioral symptoms among Veterans with a mild traumatic brain injury (mTBI); and whether Veterans in underrepresented racial/ethnic groups with high neighborhood disadvantage experience the most severe symptoms.

SETTING

Outpatient Veterans Health Administration (VHA).

PARTICIPANTS

Veterans with the following data available in the electronic health record (2014-2020): (1) clinician-confirmed mTBI and complete neurobehavioral symptom inventory (NSI) as part of their comprehensive traumatic brain injury evaluation (CTBIE) and (2) area deprivation index (ADI) scores assessing neighborhood disadvantage from the same quarter as their CTBIE.

DESIGN

Retrospective cohort study. Latent variable regression was used to examine unique and interactive relationships between neighborhood disadvantage, race/ethnicity, and neurobehavioral symptoms.

MAIN MEASURES

NSI and ADI national percentile rank.

RESULTS

The study included 58 698 eligible Veterans. Relative to Veterans in the first quintile of ADI national percentile rank, representing those with the least neighborhood disadvantage, Veterans in the ADI quintiles indicating greater neighborhood disadvantage reported more severe vestibular, sensory, mood-behavioral, and cognitive symptoms. The strongest associations between neighborhood disadvantage and neurobehavioral symptoms were observed within the sensory ( β = 0.07-0.16) and mood-behavioral domains ( β = 0.06-0.15). Statistical interactions indicated that the association between underrepresented racial/ethnic group status (vs. identifying as white, non-Hispanic) and the severity of neurobehavioral symptoms did not differ among those with severe neighborhood disadvantage versus those without.

CONCLUSION

Veterans with mTBI living in more disadvantaged neighborhoods reported more severe neurobehavioral symptoms relative to those in the most advantaged neighborhoods, with the strongest relationships detected within the sensory and mood-behavioral domains. While neighborhood disadvantage and underrepresented race/ethnicity were both independently associated with symptoms, these factors did not interact to produce more severe symptoms. Findings suggest that addressing factors driving socioeconomic disadvantage may assist in mitigating symptoms in this population.

Neurobehavioral Symptoms Partially Mediate the Effects of Depression and PTSD on Participation for Veterans With Mild Traumatic Brain Injury: A Cross-Sectional Study

OBJECTIVE

To examine whether neurobehavioral symptoms mediate the relationship between comorbid mental health conditions (major depressive disorder [MDD] and/or posttraumatic stress disorder [PTSD]) and participation restriction among Veterans with mild traumatic brain injury (mTBI).

SETTING

Veterans Health Administration (VHA).

PARTICIPANTS

National sample of Veterans with mTBI who received VHA outpatient care between 2012 and 2020.

DESIGN

Secondary data analysis of VHA clinical data. We specified a latent variable path model to estimate relationships between: (1) comorbid mental health conditions and 3 latent indicators of neurobehavioral symptoms (vestibular-sensory; mood-behavioral; cognitive); (2) latent indicators of neurobehavioral symptoms and 2 latent indicators of participation restriction (social and community participation; productivity); and (3) comorbid mental health conditions and participation restriction.

MAIN MEASURES

International Classification of Diseases codes, Neurobehavioral Symptom Inventory, and Mayo-Portland Adaptability Inventory Participation Index to measure mental health conditions, neurobehavioral symptoms, and participation restrictions, respectively.

RESULTS

Indirect effect estimates indicated that comorbid MDD and/or PTSD was associated with greater social and community participation restrictions, as mediated by mood-behavioral (β = .22-.33; 99% CI 0.18-0.4; small to medium effect) and cognitive symptoms (β = .08-.13; 99% CI 0.05-0.18; small effect), and with greater productivity restrictions, as mediated by vestibular-sensory (β = .06-.11; 99% CI 0.04-0.15; small effect) and cognitive symptoms (β = .08-.13; 99% CI 0.05-0.18; small effect). Direct effect estimates indicated that comorbid MDD and/or PTSD was associated with greater challenges with both social and community participation (β = .19-.40; 99% CI 0.12-0.49; small to medium effect) and productivity (β = .08-.44; 99% CI -0.02 to 0.55; small to medium effect).

CONCLUSION

Neurobehavioral symptoms partially mediated the impact of MDD and/or PTSD on participation restrictions among Veterans with mTBI. These findings advance the understanding of explanatory mechanisms underlying participation challenges among Veterans with comorbid mTBI and mental health challenges, thereby informing the development of tailored intervention strategies.

On-TRACC Pilot Study: A Novel Intervention for Persistent Post-Concussive Cognitive Symptoms

OBJECTIVE

To present the results of a pilot study of On-TRACC (Tools for Recovery and Clinical Care), a novel intervention for individuals experiencing persistent cognitive difficulties after mild traumatic brain injury (mTBI). On-TRACC is a 5-session, 1:1 manualized treatment that integrates psychoeducation, cognitive rehabilitation strategies, and self-management skills to target symptoms and increase understanding of the interaction between cognitive difficulties, injury history, and comorbid medical and psychological conditions. The primary study goals were to evaluate the feasibility, acceptability, and preliminary effectiveness of On-TRACC.

SETTING

Veterans Affairs medical center and an academic medical center.

PARTICIPANTS

Veterans and civilian adults (n = 28) >3 months post-mTBI with current self-reported cognitive difficulties.

DESIGN

In this single-group, open-label pilot study, all participants received On-TRACC (5 sessions) via video-based telehealth.

MAIN MEASURES

Primary measures were feasibility (eg, session attendance and homework completion rate, dropout rate, and treatment fidelity) and acceptability (treatment satisfaction/helpfulness ratings). Preliminary effectiveness was explored by measuring pre- to post-intervention change in cognitive symptom level and attribution, perceived self-efficacy, use of compensatory strategies, daily functioning, quality of life, and planned future engagement in health care.

RESULTS

The On-TRACC completion rate for all enrolled participants was 79% (with 88% treatment completion rate for participants who started On-TRACC); homework was fully or partially completed for 98% of attended sessions. Treatment satisfaction ratings were high, with 95% satisfied with the information and skills learned. There were no adverse events. Positive pre- to posttreatment changes were seen in cognitive self-efficacy, symptom attribution, functional status, quality of life, and planned engagement in care for comorbid conditions.

CONCLUSION

On-TRACC was a feasible and acceptable intervention for individuals with chronic cognitive difficulties following mTBI. Additional research, including a randomized clinical trial, is needed to evaluate the efficacy of this intervention and its long-term impact on outcomes in this clinical population.

The Neurobehavioral Symptom Inventory: Psychometric Properties and Symptom Comparisons in Women With and Without Brain Injuries Due to Intimate Partner Violence

This study psychometrically evaluated the Neurobehavioral Symptom Inventory (NSI) among women survivors of intimate partner violence (IPV) and compared symptoms between women with no brain injury history (n = 93) and women with IPV-related brain injury history (n = 112). Women completed the NSI and questionnaires on traumatic brain injury (TBI), hypoxic-ischemic brain injury (HI-BI), and lifetime IPV history. A four-factor NSI model, including affective, somatosensory, cognitive, and vestibular factors, had the best fit (comparative fit index = 0.970, root mean square error of approximation = 0.064), with strong reliability for the total score (ω = .93) and subscale scores (ω range = .72-.89). In group comparisons, women with IPV-related brain injuries reported greater total, affective, and cognitive symptom severity after adjusting for age and education; however, no group differences were observed after adjusting for IPV severity. When examining lifetime number of brain injuries, HI-BI count was independently predictive of total, cognitive, and vestibular symptom severity after adjusting for age, education, and IPV severity; whereas TBI count did not independently predict any NSI scores after adjusting for these covariates. The NSI had acceptable psychometric properties for measuring neurobehavioral symptoms among women survivors of IPV. The association between HI-BI count and cognitive and vestibular symptoms may indicate the importance of studying repetitive nonfatal strangulation as an injury mechanism in this population.

Massed treatment of posttraumatic stress disorder, traumatic brain injury, and co-occurring conditions: the Home Base intensive outpatient program for military veterans and service members

The two-week Home Base Intensive Clinical Program (ICP) provides treatment to veterans and active duty service members suffering from primary diagnoses of posttraumatic stress disorder (PTSD), traumatic brain injury (TBI), anxiety, or depression. First launched in 2015, this paper provides a programmatic update, including new treatment components implemented since inception, and examines outcomes for all participants who entered the program from September 2015 to July 2024 (n = 2561). The Home Base ICP provides a massed care approach through daily individual Prolonged Exposure, Cognitive Processing Therapy, Unified Protocol, or cognitive rehabilitation, along with groups targeting coping skills. Participants entering the program are provided with core group programming, as well as individualized therapy sessions tailored to their unique needs and symptom presentation. Supplemental dual recovery support is also available for all participants with co-occurring substance use or behavioral addiction concerns. Participants' support people receive education, support, and case management services. Participants have a multidisciplinary team comprising therapists, psychopharmacology providers, case managers, nurses, and wellness providers. Results demonstrate that program participants exhibited statistically significant reductions in PTSD symptoms (Cohen's d = 0.80), depression (d = 0.68), post-concussion symptoms (d = 0.71), and increased satisfaction in social roles (d = -0.65). Completion rate was 94.60% (n = 2422), suggesting that the Home Base ICP is a well-received and effective model of care for veterans and service members.

Exposure to Adverse Childhood Experiences Predicts Increased Neurobehavioral Symptom Reporting in Adults with Mild Traumatic Brain Injury

The objective of this study was to understand whether exposure to adverse childhood experiences (ACEs) before 18 years of age predicts increased neurobehavioral symptom reporting in adults presenting for treatment secondary to persistent symptoms after mild traumatic brain injury (mTBI). This cross-sectional study identified 78 individuals with mTBI from 2014 to 2018 presenting for treatment to an outpatient multidisciplinary rehabilitation clinic. Neurobehavioral symptom inventory (NSI-22) scores were collected on admission, and ACEs for each patient were abstracted by medical record review. A linear regression model was used to assess if an individual who experienced at least one ACE before age 18 resulted in significantly different neurobehavioral scores compared with those not reporting any history of an ACE before age 18. Participants who reported at least one ACE before age 18 had significantly increased NSI-22 scores on admission to the rehabilitation clinic compared with patients without history of ACEs (mean difference 10.1, p = 0.011), adjusted for age and gender. For individuals presenting for treatment after mTBI, a history of ACEs before age 18 was associated with increased neurobehavioral symptoms.

Validation of a modified-composite autonomic symptom score (COMPASS-31) as an outcome measure for persistent autonomic symptoms post-concussion: an observational pilot study

OBJECTIVE

Persistent symptoms post-mild traumatic brain injury (mTBI) includes autonomic dysregulation (AD). The composite autonomic symptoms score, (COMPASS-31), was developed to quantify AD symptom severity in the last year, which limits clinical utility. The primary aim was to determine validity of a modified-COMPASS-31 measuring symptoms in the last month compared to the original, secondarily to compare both original and modified versions to the Neurobehavioral Symptom Inventory (NSI), and tertiarily to detect change post-treatment of the modified-COMPASS-31 compared to NSI and headache intensity (HI).

PARTICIPANTS

Thirty-three military personnel with persistent headache post-mTBI.

MAIN OUTCOME MEASURES

Total and domain scores for COMPASS-31 (original vs. modified) NSI and HI at baseline. Change in modified-COMPASS-31. NSI, and HI.

RESULTS

Baseline COMPASS-31 versions were comparable and highly correlated (r = 0.72, p < 0.001), they were moderately correlated at best to the NSI (r < 0.6), which may suggest differences in measurement metrics. The mean change in modified-COMPASS-31 scores (15.4/100, effect size 0.8) was mild to moderately correlated to the change in HI (r = 0.39) score, but not to NSI (r = 0.28).

CONCLUSION

The modified-COMPASS-31 appears to be valid, can measure change of AD symptom severity, and is recommended as an outcome measure.

Disentangling subjective symptom complaints and objective cognitive performance in veterans: Impact of posttraumatic stress disorder and lifetime traumatic brain injury burden

Self-reported histories of mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) symptoms are prevalent among post-9/11 veterans. Both are associated with subjective and often overlapping symptom complaints, but variably with objective neuropsychological test performances. These outcomes are seldom explored in relation to lifetime mTBI burden. This cross-sectional study examined associations of PTSD and lifetime mTBI with subjective (persistent symptoms after concussion and cognitive complaints) and objective (performances across five cognitive domains) measures among 46 veterans. Within this sample, 20 veterans had Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) confirmed PTSD (PTSD+), whereas 26 demographically-similar participants did not meet criteria (PTSD-). The Boston Assessment of Traumatic Brain Injury-Lifetime (BAT-L) yielded total mTBI scores ranging from 0 to 8. Regressions showed PTSD was associated with increased subjective symptoms/cognitive complaints, along with reduced verbal fluency, visuospatial memory, and processing speed performances. Lifetime mTBI burden was associated with subjective symptoms, but not with objective cognitive test performance, after controlling for PTSD. No significant interactions were observed. Exploratory correlations suggested that all PTSD symptom clusters were generally associated with the subjective and objective measures. However, fewer significant associations emerged within the PTSD+/- groups separately, with each group yielding somewhat different patterns of relationships. PTSD and increasing mTBI burden are consistently associated with negative subjective symptoms, including cognitive complaints. Each condition likely explains some degree of unique variance in symptom reporting. PTSD is associated with poorer objective cognition on some tasks, including processing speed, executive functioning, and learning/memory. Implications are explored.

Measurement Invariance of the Neurobehavioral Symptom Inventory in Male and Female Million Veteran Program Enrollees Completing the Comprehensive Traumatic Brain Injury Evaluation

This study evaluated measurement invariance across males and females on the Neurobehavioral Symptom Inventory (NSI) in U.S. military veterans enrolled in the VA Million Veteran Program. Participants (N = 17,059; males: n = 15,450; females: n = 1,609) included Veterans who took part in the VA Traumatic Brain Injury (TBI) Screening and Evaluation Program and completed the NSI. Multiple-group confirmatory factor analyses investigated measurement invariance of the NSI 4-factor model. The configural (comparative fit index [CFI] = 0.948, root mean square error of approximation [RMSEA] = 0.060) and metric (CFI = 0.948, RMSEA = 0.058) invariance models showed acceptable fit. There was a minor violation of scalar invariance (Δχ2 = 232.50, p < .001); however, the degree of noninvariance was mild (ΔCFI = -0.002, Δ RMSEA = 0 . 000 ). Our results demonstrate measurement invariance across sex, suggesting that the NSI 4-factor model can be used to accurately assess symptoms in males and females following TBI. Findings highlight the importance of considering validity of measurement across study groups to increase confidence that a measure is interpreted similarly by respondents from different subgroups.

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

OBJECTIVE

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

SETTING

Outpatient Veterans Health Administration (VHA).

PARTICIPANTS

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

DESIGN

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

MAIN MEASURES

Latent classes identified using NSI items.

RESULTS

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

CONCLUSION

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

White Matter Alterations in Military Service Members With Remote Mild Traumatic Brain Injury

Importance

Mild traumatic brain injury (mTBI) is the signature injury experienced by military service members and is associated with poor neuropsychiatric outcomes. Yet, there is a lack of reliable clinical tools for mTBI diagnosis and prognosis.

Objective

To examine the white matter microstructure and neuropsychiatric outcomes of service members with a remote history of mTBI (ie, mTBI that occurred over 2 years ago) using diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI).

Design, Setting, and Participants

This case-control study examined 98 male service members enrolled in a study at the National Intrepid Center of Excellence. Eligible participants were active duty status or able to enroll in the Defense Enrollment Eligibility Reporting system, ages 18 to 60 years, and had a remote history of mTBI; controls were matched by age.

Exposures

Remote history of mTBI.

Main Outcomes and Measures

White matter microstructure was assessed using a region-of-interest approach of skeletonized diffusion images, including DTI (fractional anisotropy, mean diffusivity, radial diffusivity and axial diffusivity) and NODDI (orientation dispersion index [ODI], isotropic volume fraction, intra-cellular volume fraction). Neuropsychiatric outcomes associated with posttraumatic stress disorder (PTSD) and postconcussion syndrome were assessed.

Results

A total of 65 male patients with a remote history of mTBI (mean [SD] age, 40.5 [5.0] years) and 33 age-matched male controls (mean [SD] age, 38.9 [5.6] years) were included in analysis. Compared with the control cohort, the 65 service members with mTBI presented with significantly more severe PTSD-like symptoms (mean [SD] PTSD CheckList-Civilian [PCL-C] version scores: control, 19.0 [3.8] vs mTBI, 41.2 [11.6]; P < .001). DTI and NODDI metrics were altered in the mTBI group compared with the control, including intra-cellular volume fraction of the right cortico-spinal tract (β = -0.029, Cohen d = 0.66; P < .001), ODI of the left posterior thalamic radiation (β = -0.006, Cohen d = 0.55; P < .001), and ODI of the left uncinate fasciculus (β = 0.013, Cohen d = 0.61; P < .001). In service members with mTBI, fractional anisotropy of the left uncinate fasciculus was associated with postconcussion syndrome (β = 5.4 × 10-3; P = .003), isotropic volume fraction of the genu of the corpus callosum with PCL-C (β = 4.3 × 10-4; P = .01), and ODI of the left fornix and stria terminalis with PCL-C avoidance scores (β = 1.2 × 10-3; P = .02).

Conclusions and Relevance

In this case-control study of military-related mTBI, the results suggest that advanced magnetic resonance imaging techniques using NODDI can reveal white matter microstructural alterations associated with neuropsychiatric symptoms in the chronic phase of mTBI. Diffusion trends observed throughout widespread white matter regions-of-interest may reflect mechanisms of neurodegeneration as well as postinjury tissue scarring and reorganization.

Factor analysis of the neurobehavioral symptom inventory in veterans with PTSD and no history of mild TBI

It is well established that long-term postconcussive symptoms following a mild traumatic brain injury (mTBI) are associated with underlying physical, emotional, and behavioral conditions. The Neurobehavioral Symptom Inventory (NSI) is a measure used to assess neurobehavioral symptoms that can occur following a mTBI and has demonstrated a 3- or 4-factor structure in veterans. The present study aimed to investigate the factor structure of veterans with PTSD without a history of mTBI. A confirmatory factor analysis (CFA) was conducted on a sample of 221 treatment-seeking veterans and service members with PTSD and without a history of mTBI. Results supported a 4-factor structure comprised of vestibular, somatic, cognitive, and affective domains in veterans with PTSD. Subsequent, correlational analyses between the four NSI factors and the four subscales of the Posttraumatic Stress Disorder Checklist - Fifth Edition (PCL-5) revealed high correspondence between the cognitive and affective factors of the NSI and the negative alterations in mood and cognitions and hyperarousal symptom subscales of PTSD. Collectively, findings demonstrated that the NSI functions similarly in veterans with PTSD with or without a history of mTBI. Findings suggest that neurobehavioral symptoms assessed by the NSI appear to be nonspecific and not explicitly associated with mTBI.

Exercise Intolerance After Mild Traumatic Brain Injury Occurs in All Subtypes in the Adult Population

Thematically grouped symptom clusters are present during the acute timeline of post-mild traumatic brain injuries (mTBI), representing clinical profiles called subtypes. Exercise intolerance has not been evaluated within the subtype classifications and, because guidelines support early submaximal aerobic exercise, further knowledge is required in regard to the exercise capabilities among the concussion subtypes. This cross-sectional study (n = 78) aimed to characterize the presence of exercise intolerance within the clinical subtypes and to explore performance on the Buffalo Concussion Treadmill Test (BCTT) in the adult subacute (2-12 weeks post-injury) mTBI population. All participants were evaluated using the BCTT to determine exercise tolerance. We first used the Neurobehavioral Symptom Inventory (NSI) questionnaire to assign each participant a primary subtype(s). To further explore all five subtypes (headache, cognitive, vestibular, ocular motor, and mood), participants were assessed using a multitude of thematically grouped assessments including self-reported questionnaires, clinical tests of vestibular and ocular motor function, balance function, and computerized cognitive testing. Thirty-seven (47%) subjects were exercise tolerant and 41 (53%) were exercise intolerant. There was no difference in the distribution of primary subtypes between the exercise tolerant and exercise intolerant groups. In addition, no significant differences were found between the exercise tolerant and exercise intolerant groups on other thematically grouped subtype assessments. The exercise intolerant group had a significantly higher resting heart rate (HR), lower percentage of age-predicted maximum HR achieved, lower Borg Rate of Perceived Exertion (RPE), and could walk on the treadmill for less time (lower duration) compared with the exercise tolerant group. The current findings suggest that exercise intolerance is common and pervasive across all five mTBI subtypes. A comprehensive mTBI assessment should include evaluation for exercise intolerance regardless of the primary clustering of symptoms and across patient populations. Therefore, early referral to physical therapists, athletic trainers, or medical clinics that can perform the BCTT may be helpful to initiate appropriate exercise prescriptions for patients with mTBI.

Post-Concussion Symptoms in Women With Head Injury Due to Intimate Partner Violence

Limited research has examined the symptom sequelae of head injuries in women survivors of intimate partner violence (IPV), despite this community being at increased risk for neurotrauma due to partner abuse. The current study compared post-concussion symptom severity between women with and without IPV-related head injuries. Women were recruited from court jurisdictions in Kentucky, USA, after receiving a protective order for partner abuse. The sample included 268 women with no prior head injuries (age: M[standard deviation (SD)] = 31.8[9.8], 77.2% White) and 251 women with lifetime IPV-related head injuries (age: M[SD] = 31.8[9.8], 88.0% White). Women with IPV-related head injuries were slightly older (t = 2.46, p = 0.014) with lower education (χ2 = 5.81, p = 0.016), were more frequently unemployed (χ2 = 9.23, p = 0.002), and had a higher likelihood of residing in a rural setting (χ2 = 30.16, p < 0.001). Women with IPV-related head injuries were also more often White (χ2 = 10.47, p = 0.001), but this group difference was almost entirely related to rural versus urban residence. Women with IPV-related head injuries reported a higher severity of lifetime physical IPV (t = 7.27, p < 0.001, d = 0.64, 95% confidence interval [CI]: [.46, .82]) and sexual IPV (t = 4.65, p < 0.001, d = 0.41 [0.24, 0.59]). A three-factor model of post-concussion symptoms, inclusive of cognitive, physical, and emotional symptoms, fit well (χ2 = 368.99, p < 0.0001, comparative fit index [CFI] = 0.974, Tucker-Lewis index [TLI] = 0.968, root mean square error of approximation [RMSEA] = 0.079 [0.071, 0.087]), and showed evidence for strong measurement invariance across women with and without IPV-related head injuries. The subscale and total scores each had acceptable reliability: cognitive (ω = 0.88 [0.86, 0.90]), physical (ω = 0.74 [0.70, 0.77]), and emotional (ω = 0.88 [0.86, 0.89]), and total score (ω = 0.93 [0.92, 0.95]). Women with IPV-related head injuries reported all individual post-concussion symptoms at a significantly higher frequency, with medium group differences in cognitive (t = 7.57, p < 0.001, d = 0.67 [0.50, 0.85]) and physical symptoms (t = 7.73, p < 0.001, d = 0.68 [0.51, 0.86]) and large group differences in emotional (t = 8.51, p < 0.001, d = 0.75 [0.57, 0.93]) and total symptoms (t = 9.07, p < 0.001, d = 0.80 [0.62, 0.98]). All sociodemographic characteristics were independently associated with post-concussion symptoms, as were physical IPV (total score: r = 0.28 [0.19, 0.35], p < 0.001) and sexual IPV severity (total score: r = 0.22 [0.13, 0.30], p < 0.001). In hierarchical regression analyses, controlling for sociodemographic characteristics (i.e., age, race/ethnicity, education, unemployment, and rural/urban residence) and physical and sexual IPV severity, IPV-related head injury was independently significant and accounted for significant additional variance when predicting cognitive (ΔR2 = 0.05, p < 0.001), physical (ΔR2 = 0.03, p < 0.001), emotional (ΔR2 = 0.07, p < 0.001), and total symptoms (ΔR2 = 0.06, p < 0.001). Negative-binomial regression resulted in similar findings. This study demonstrates that multiple sociodemographic and IPV history variables are related to post-concussion symptom severity, but IPV-related head injury was independently associated with greater symptom severity. Women with IPV-related head injuries may be at increased risk for unaddressed health problems spanning cognitive, physical, and emotional domains. Future research is needed to psychometrically evaluate assessment instruments for this population and to assess efficacy of interventions to address their unique health care needs.

Regional associations of white matter integrity and neurological, post-traumatic stress disorder and autonomic symptoms in Veterans with and without history of loss of consciousness in mild TBI

Background

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) share overlapping symptom presentations and are highly comorbid conditions among Veteran populations. Despite elevated presentations of PTSD after mTBI, mechanisms linking the two are unclear, although both have been associated with alterations in white matter and disruptions in autonomic regulation. The present study aimed to determine if there is regional variability in white matter correlates of symptom severity and autonomic functioning in a mixed sample of Veterans with and without PTSD and/or mTBI (N = 77).

Methods

Diffusion-weighted images were processed to extract fractional anisotropy (FA) values for major white matter structures. The PTSD Checklist-Military version (PCL-M) and Neurobehavioral Symptom Inventory (NSI) were used to determine symptom domains within PTSD and mTBI. Autonomic function was assessed using continuous blood pressure and respiratory sinus arrythmia during a static, standing angle positional test. Mixed-effect models were used to assess the regional specificity of associations between symptom severity and white matter, with FA, global symptom severity (score), and white matter tract (tract) as predictors. Additional interaction terms of symptom domain (i.e., NSI and PCL-M subscales) and loss of consciousness (LoC) were added to evaluate potential moderating effects. A parallel analysis was conducted to explore concordance with autonomic functioning.

Results

Results from the two-way Score × Tract interaction suggested that global symptom severity was associated with FA in the cingulum angular bundle (positive) and uncinate fasciculus (negative) only, without variability by symptom domain. We also found regional specificity in the relationship between FA and autonomic function, such that FA was positively associated with autonomic function in all tracts except the cingulum angular bundle. History of LoC moderated the association for both global symptom severity and autonomic function.

Conclusions

Our findings are consistent with previous literature suggesting that there is significant overlap in the symptom presentation in TBI and PTSD, and white matter variability associated with LoC in mTBI may be associated with increased PTSD-spectra symptoms. Further research on treatment response in patients with both mTBI history and PTSD incorporating imaging and autonomic assessment may be valuable in understanding the role of brain injury in treatment outcomes and inform treatment design.

Symptom Attribution and Neuropsychological Outcomes Among Treatment-Seeking Veterans With a History of Traumatic Brain Injury

OBJECTIVE

In this cross-sectional study, the authors aimed to examine relationships between illness perception, measured as symptom attribution, and neurobehavioral and neurocognitive outcomes among veterans with a history of traumatic brain injury (TBI).

METHODS

This study included 55 treatment-seeking veterans (N=43 with adequate performance validity testing) with a remote history of TBI (80% with mild TBI). Veterans completed a clinical interview, self-report questionnaires, and a neuropsychological assessment. A modified version of the Neurobehavioral Symptom Inventory (NSI) was administered to assess neurobehavioral symptom endorsement and symptom attribution. Composite scores were calculated from standardized cognitive tests to assess specific aspects of objective cognitive functioning, including memory, executive functioning, attention and working memory, and processing speed.

RESULTS

The symptoms most frequently attributed to TBI included forgetfulness, poor concentration, slowed thinking, and headaches. There was a significant positive association between symptom attribution and overall symptom endorsement (NSI total score) (r=0.675) and endorsement of specific symptom domains (NSI symptom domain scores) (r=0.506-0.674), indicating that greater attribution of symptoms to TBI was associated with greater symptom endorsement. Furthermore, linear regressions showed that symptom attribution was significantly associated with objective cognitive functioning, whereas symptom endorsement generally did not show this relationship. Specifically, greater attribution of symptoms to TBI was associated with worse executive functioning (β=-0.34), attention and working memory (β=-0.43), and processing speed (β=-0.35).

CONCLUSIONS

These findings suggest that veterans who routinely attribute neurobehavioral symptoms to their TBI are at greater risk of experiencing poor long-term outcomes, including elevated symptom endorsement and worse objective cognition. Although more research is needed to understand how illness perception influences outcomes in this population, these preliminary results highlight the importance of early psychoeducation regarding the anticipated course of recovery following TBI.

Evaluation of clinical outcomes and employment status in veterans with dual diagnosis of traumatic brain injury and spinal cord injury

PURPOSE

To examine clinical outcomes and employment status in Veterans with and without a dual diagnosis of traumatic brain injury (TBI) and spinal cord injury (SCI).

METHODS

This cross-sectional study examined a national sample of Veterans enrolled in the VA Million Veteran Program who completed the Comprehensive TBI Evaluation (CTBIE) as part of the Veterans Health Administration's TBI Screening and Evaluation Program. Veterans (N = 12,985) were classified into the following TBI/SCI groups using CTBIE data: those with a dual diagnosis of TBI and SCI (TBI+/SCI+); those with a history of TBI but no SCI (TBI+/SCI-); and those with no history of TBI or SCI (TBI-/SCI-; i.e., the control group). CTBIE-derived outcomes included neurobehavioral symptoms, comorbid psychiatric symptoms, pain and pain interference, and employment status.

RESULTS

Chi-square analyses showed significant associations between TBI/SCI group and all clinical outcomes evaluated (all p's < .001; V = 0.07-0.11). In general, the TBI+/SCI+ and TBI +/SCI- groups endorsed comparable levels of neurobehavioral symptoms, psychiatric symptoms, and pain, but significantly greater rates of symptoms and pain relative to the TBI-/SCI- group. Effect sizes for all pairwise comparisons were small (φ = 0.01-0.11). Finally, there was no significant association between TBI/SCI group and employment status (p = .170; V = 0.02), with all three groups showing relatively comparable rates of unemployment.

CONCLUSIONS

Regardless of SCI status, Veterans with TBI history endorsed poorer clinical outcomes than Veterans without TBI and SCI. However, rates of unemployment were similarly high across all three groups. Findings suggest that any Veteran completing the CTBIE may be at risk for poor clinical and employment outcomes.

Symptom attribution is a stronger predictor of PVT-failure than symptom endorsement in treatment-seeking Veterans with remote mTBI history: A pilot study

OBJECTIVE

To examine relationships between performance validity testing (PVT), neurobehavioral symptom endorsement, and symptom attribution in Veterans with a history of mild traumatic brain injury (mTBI).

METHOD

Participants included treatment-seeking Veterans (n = 37) with remote mTBI histories who underwent a neuropsychological assessment and completed a modified version of the Neurobehavioral Symptom Inventory (NSI) to assess symptom endorsement and symptom attribution (the latter evaluated by having Veterans indicate whether they believed each NSI symptom was caused by their mTBI). Veterans were divided into two subgroups, PVT-Valid (n = 25) and PVT-Invalid (n = 12).

RESULTS

Independent samples t-tests showed that two of five symptom endorsement variables and all five symptom attribution variables were significantly different between PVT groups (PVT-Invalid > PVT-Valid; Cohen's d = 0.67-1.02). Logistic regression analyses adjusting for PTSD symptoms showed that symptom endorsement (Nagelkerke's R2 = .233) and symptom attribution (Nagelkerke's R2 = .279) significantly distinguished between PVT groups. According to the Wald criterion, greater symptom endorsement (OR = 1.09) and higher attribution of symptoms to mTBI (OR = 1.21) each reliably predicted PVT-failure.

CONCLUSIONS

While both symptom endorsement and symptom attribution were significantly associated with PVT-failure, our preliminary results suggest that symptom attribution is a stronger predictor of PVT-failure. Results highlight the importance of assessing symptom attribution to mTBI in this population.

Exploring the relationship between sleep apnea and vestibular symptoms following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a complex health problem in military veterans and service members (V/SM) that often involves comorbid vestibular impairment. Sleep apnea is another comorbidity that may exacerbate, and/or be exacerbated by, vestibular dysfunction.

OBJECTIVE

To examine the relationship between sleep apnea and vestibular symptoms in V/SM diagnosed with TBI of any severity.

DESIGN

Multicenter cohort study; cross-sectional sample.

SETTING

In-patient TBI rehabilitation units within five Veterans Affairs (VA) Polytrauma Rehabilitation Centers.

PARTICIPANTS

V/SM with a diagnosis of TBI (N = 630) enrolled in the VA TBI Model Systems study.

INTERVENTION

Not applicable.

METHODS

A multivariable regression model was used to evaluate the association between sleep apnea and vestibular symptom severity while controlling for relevant covariates, for example, posttraumatic stress disorder (PTSD).

MAIN OUTCOME MEASURES

Lifetime history of sleep apnea was determined via best source reporting. Vestibular disturbances were measured with the 3-item Vestibular subscale of the Neurobehavioral Symptom Inventory (NSI).

RESULTS

One third (30.6%) of the sample had a self-reported sleep apnea diagnosis. Initial analysis showed that participants who had sleep apnea had more severe vestibular symptoms (M = 3.84, SD = 2.86) than those without sleep apnea (M = 2.88, SD = 2.67, p < .001). However, when the data was analyzed via a multiple regression model, sleep apnea no longer reached the threshold of significance as a factor associated with vestibular symptoms. PTSD severity was shown to be significantly associated with vestibular symptoms within this sample (p < .001).

CONCLUSION

Analysis of these data revealed a relationship between sleep apnea and vestibular symptoms in V/SM with TBI. The significance of this relationship was affected when PTSD symptoms were factored into a multivariable regression model. However, given that the mechanisms and directionality of these relationships are not yet well understood, we assert that in terms of clinical relevance, providers should emphasize screening for each of the three studied comorbidities (sleep apnea, vestibular symptoms, and PTSD).

Mild traumatic brain injury as a cause of adult growth hormone deficiency: Diagnosis and treatment

In recent years, mild traumatic brain injury (mTBI) has been recognized as a cause of acquired growth hormone deficiency (AGHD) and is likely much more prevalent than previous estimates. There is great overlap between persistent symptoms following mTBI and those of AGHD and it is possible that these persistent symptoms of mTBI are, at least in part, due to or aggravated by AGHD. This article reviews the current literature of AGHD following mTBI, and proposes practice recommendations for the screening, diagnosis, and management of patients with AGHD following mTBI.

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.

An Examination of Racial/Ethnic Differences on the Neurobehavioral Symptom Inventory Among Veterans Completing the Comprehensive Traumatic Brain Injury Evaluation: A Veterans Affairs Million Veteran Program Study

OBJECTIVE

The purpose of this study was to explore racial/ethnic differences in neurobehavioral symptom reporting and symptom validity testing among military veterans with a history of traumatic brain injury (TBI).

METHOD

Participants of this observational cross-sectional study (N = 9,646) were post-deployed Iraq-/Afghanistan-era veterans enrolled in the VA's Million Veteran Program with a clinician-confirmed history of TBI on the Comprehensive TBI Evaluation (CTBIE). Racial/ethnic groups included White, Black, Hispanic, Asian, Multiracial, Another Race, American Indian or Alaska Native, and Native Hawaiian or Other Pacific Islander. Dependent variables included neurobehavioral symptom domains and symptom validity assessed via the Neurobehavioral Symptom Inventory (NSI) and Validity-10, respectively.

RESULTS

Chi-square analyses showed significant racial/ethnic group differences for vestibular, somatic/sensory, and affective symptoms as well as for all Validity-10 cutoff scores examined (≥33, ≥27, ≥26, >22, ≥22, ≥13, and ≥7). Follow-up analyses compared all racial/ethnic groups to one another, adjusting for sociodemographic- and injury-related characteristics. These analyses revealed that the affective symptom domain and the Validity-10 cutoff of ≥13 revealed the greatest number of racial/ethnic differences.

CONCLUSIONS

Results showed significant racial/ethnic group differences on neurobehavioral symptom domains and symptom validity testing among veterans who completed the CTBIE. An enhanced understanding of how symptoms vary by race/ethnicity is vital so that clinical care can be appropriately tailored to the unique needs of all veterans. Results highlight the importance of establishing measurement invariance of the NSI across race/ethnicity and underscore the need for ongoing research to determine the most appropriate Validity-10 cutoff score(s) to use across racially/ethnically diverse veterans.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSION

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

Characterizing Sex Differences in Clinical and Functional Outcomes Among Military Veterans with a Comprehensive Traumatic Brain Injury Evaluation (CTBIE): A Million Veteran Program (MVP) Study

Using a diverse sample of military Veterans enrolled in the VA's Million Veteran Program (N=14,378; n=1,361 females [9.5%]; all previously deployed), we examined sex differences on the Comprehensive Traumatic Brain Injury Evaluation (CTBIE), a structured traumatic brain injury (TBI) interview routinely administered within the VA. Confirmed TBI diagnoses were more frequent among males than females (65% vs. 58%). Additionally, when compared to females, a greater proportion of males with CTBIE-confirmed TBI histories experienced blast-related injuries and were employed. In contrast, a greater proportion of females reported experiencing falls, sustaining a TBI since deployment, and having more severe neurobehavioral symptoms (particularly affective-related symptoms). Results indicate that males and females experience differential clinical and functional outcomes in the aftermath of military TBI. Findings underscore the need to increase female representation in TBI research to increase understanding of sex-specific experiences with TBI and to improve the clinical care targeted to this vulnerable population.

Post-concussive symptoms mediate the relationship between sleep problems and participation restrictions among veterans with mild traumatic brain injury

Background

Sleep problems are common among Veterans with mild traumatic brain injury (mTBI) and may contribute to participation restrictions. However, explanatory mechanisms underlying this relationship are poorly understood. Sleep problems are associated with post-concussive symptoms (e.g., headaches). In turn, post-concussive symptoms contribute to participation restrictions. We hypothesized that post-concussive symptom severity mediates the purported relationship between sleep problems and participation restrictions among Veterans with mTBI.

Materials and Methods

This study was a retrospective analysis of clinical data among 8,733 Veterans with mTBI receiving Veterans Health Administration outpatient care. Sleep problems (yes/no) were identified using the sleep-related item from the Neurobehavioral Symptom Inventory (NSI). Post-concussive symptoms were measured using remaining NSI items. Participation restrictions were measured using the Mayo-Portland Adaptability Inventory Participation Index. We specified a latent variable path model to estimate relationships between: (1) sleep problems and three latent indicators of post-concussive symptoms [vestibular-sensory (e.g., headache)]; mood-behavioral [e.g., anxiety]; cognitive [e.g., forgetfulness]); and, (2) the three latent indicators of post-concussive symptoms and two latent indicators of participation restrictions (social and community participation [e.g., leisure activities]; productivity [e.g., financial management]). We examined the indirect effects of sleep problems upon participation restrictions, as mediated by post-concussive symptoms. Estimates were adjusted for sociodemographic factors (e.g., age), injury characteristics (e.g., blast), and co-morbid conditions (e.g., depression).

Results

87% of Veterans reported sleep problems. Sleep problems were associated with greater social and community participation restrictions, as mediated by mood-behavioral (β = 0.41, p < 0.001) and cognitive symptoms (β = 0.13, p < 0.001). There was no evidence that vestibular-sensory symptoms mediated this relationship (β = -0.01, p = 0.48). Sleep problems were associated with greater productivity restrictions, as mediated by vestibular-sensory (β = 0.16, p < 0.001) and cognitive symptoms (β = 0.14, p < 0.001). There was no evidence that mood-behavioral symptoms mediated this relationship (β = 0.02, p = 0.37).

Discussion

Findings suggest that evidence-based sleep treatment should occupy a prominent role in the rehabilitation of Veterans with mTBI. Indirect effects of sleep problems differed when considering impact on social and community participation vs. productivity, informing individualized rehabilitative care for Veterans with mTBI.

Oculomotor, vestibular, reaction time, and cognitive tests as objective measures of neural deficits in patients post COVID-19 infection

Objective

An alarming proportion (>30%) of patients affected by SARS-CoV-2 (COVID-19) continue to experience neurological symptoms, including headache, dizziness, smell and/or taste abnormalities, and impaired consciousness (brain fog), after recovery from the acute infection. These symptoms are self-reported and vary from patient to patient, making it difficult to accurately diagnose and initiate a proper treatment course. Objective measures to identify and quantify neural deficits underlying the symptom profiles are lacking. This study tested the hypothesis that oculomotor, vestibular, reaction time, and cognitive (OVRT-C) testing using eye-tracking can objectively identify and measure functional neural deficits post COVID-19 infection.

Methods

Subjects diagnosed with COVID-19 (n = 77) were tested post-infection with a battery of 20 OVRT-C tests delivered on a portable eye-tracking device (Neurolign Dx100). Data from 14 tests were compared to previously collected normative data from subjects with similar demographics. Post-COVID subjects were also administered the Neurobehavioral Symptom Inventory (NSI) for symptom evaluation.

Results

A significant percentage of post COVID-19 patients (up to 86%) scored outside the norms in 12 out of 14 tests, with smooth pursuit and optokinetic responses being most severely affected. A multivariate model constructed using stepwise logistic regression identified 6 metrics as significant indicators of post-COVID patients. The area under the receiver operating characteristic curve (AUC) was 0.89, the estimated specificity was 98% (with cutoff value of 0.5) and the sensitivity was 88%. There were moderate but significant correlations between NSI domain key variables and OVRT-C tests.

Conclusions

This study demonstrates the feasibility of OVRT-C testing to provide objective measures of neural deficits in people recovering from COVID-19 infection. Such testing may serve as an efficient tool for identifying hidden neurological deficits post COVID-19, screening patients at risk of developing long COVID, and may help guide rehabilitation and treatment strategies.

Subjective cognitive and psychiatric well-being in U.S. Military Veterans screened for deployment-related traumatic brain injury: A Million Veteran Program Study

The purpose of this study was to examine subjective cognitive and psychiatric functioning in post-deployed military Veterans who underwent the Veterans Health Administration's Traumatic Brain Injury (TBI) Screening and Evaluation Program and enrolled in the VA's Million Veteran Program (MVP). Veterans (N = 7483) were classified into three groups based on outcomes from the TBI Screening and Evaluation Program: (1) negative TBI screen ('Screen-'), (2) positive TBI screen but no TBI diagnosis ('Screen+/TBI-'), or (3) positive TBI screen and TBI diagnosis ('Screen+/TBI+'). Chi-square analyses revealed significant group differences across all self-reported cognitive and psychiatric health conditions (e.g., memory loss, depression), and ANCOVAs similarly showed a significant association between group and subjective symptom reporting. Specifically, the relationship between TBI group and clinical outcome (i.e., health conditions and symptoms) was such that the Screen+/TBI+ group fared the worst, followed by the Screen+/TBI- group, and finally the Screen- group. However, evaluation of effect sizes suggested that Veterans in the two Screen+ groups (Screen+/TBI+ and Screen+/TBI-) are faring similarly to one another on subjective cognitive and psychiatric functioning, but that both Screen+ groups are faring significantly worse than the Screen- group. Our results have meaningful clinical implications and suggest that Veterans who screen positive for TBI, regardless of ultimate TBI diagnosis, be eligible for similar clinical services so that both groups can benefit from valuable treatments and therapeutics. Finally, this research sets the stage for follow-up work to be conducted within MVP that will address the neurobiological underpinnings of cognitive and psychiatric distress in this population.

Free-living gait does not differentiate chronic mTBI patients compared to healthy controls

Background

Physical function remains a crucial component of mild traumatic brain injury (mTBI) assessment and recovery. Traditional approaches to assess mTBI lack sensitivity to detect subtle deficits post-injury, which can impact a patient’s quality of life, daily function and can lead to chronic issues. Inertial measurement units (IMU) provide an opportunity for objective assessment of physical function and can be used in any environment. A single waist worn IMU has the potential to provide broad/macro quantity characteristics to estimate gait mobility, as well as more high-resolution micro spatial or temporal gait characteristics (herein, we refer to these as measures of quality). Our recent work showed that quantity measures of mobility were less sensitive than measures of turning quality when comparing the free-living physical function of chronic mTBI patients and healthy controls. However, no studies have examined whether measures of gait quality in free-living conditions can differentiate chronic mTBI patients and healthy controls. This study aimed to determine whether measures of free-living gait quality can differentiate chronic mTBI patients from controls.

Methods

Thirty-two patients with chronic self-reported balance symptoms after mTBI (age: 40.88 ± 11.78 years, median days post-injury: 440.68 days) and 23 healthy controls (age: 48.56 ± 22.56 years) were assessed for ~ 7 days using a single IMU at the waist on a belt. Free-living gait quality metrics were evaluated for chronic mTBI patients and controls using multi-variate analysis. Receiver operating characteristics (ROC) and Area Under the Curve (AUC) analysis were used to determine outcome sensitivity to chronic mTBI.

Results

Free-living gait quality metrics were not different between chronic mTBI patients and controls (all p > 0.05) whilst controlling for age and sex. ROC and AUC analysis showed stride length (0.63) was the most sensitive measure for differentiating chronic mTBI patients from controls.

Conclusions

Our results show that gait quality metrics determined through a free-living assessment were not significantly different between chronic mTBI patients and controls. These results suggest that measures of free-living gait quality were not impaired in our chronic mTBI patients, and/or, that the metrics chosen were not sensitive enough to detect subtle impairments in our sample.

Characteristics of Responders and Nonresponders in a Military Postconcussion Rehabilitation Program

OBJECTIVE

To characterize treatment responders and nonresponders as measured by the Neurobehavioral Symptom Inventory (NSI) in order to understand whether certain traits in our patient population would characterize favorable response.

SETTING

Brain Injury Rehabilitation Service at Brooke Army Medical Center, Fort Sam Houston, San Antonio, Texas.

PATIENTS

In total, 655 active duty military patients with a diagnosis of mild traumatic brain injury (mTBI) who received treatment between 2007 and 2020 and completed self-report measures as part of routine care.

DESIGN

Observational retrospective analysis of outpatient clinical outcomes data.

MAIN MEASURES

The primary outcome measure was the NSI, divided into the responder and nonresponder groups. Responders were defined by reliable change in NSI total score (decrease of ≥8 points from intake to discharge).

FINDINGS

Responders (n = 395) reported a higher level of symptom burden at intake on the NSI. Women responded proportionally more (70%) than men (58%). After treatment, responders reported improvements on all measures evaluated while nonresponders reported no change or slightly worse symptoms. Logistic regression analysis showed that posttraumatic stress symptoms at intake decreased odds of favorable treatment response while satisfaction with social relationships increased odds of favorable treatment response.

CONCLUSION

The results from this process improvement project suggested that posttraumatic symptoms warrant programmatic attention in TBI clinics while social relationships may be a protective factor that can be capitalized to enhance troop readiness. Systematic examination of these characteristics should be conducted on a larger population within the military health system.

Correlations Between the Neurobehavioral Symptom Inventory and Other Commonly Used Questionnaires for Traumatic Brain Injury

OBJECTIVE

To evaluate the correlations between the Neurobehavioral Symptom Inventory (NSI) and other questionnaires commonly administered within military traumatic brain injury clinics.

SETTING

Military outpatient traumatic brain injury clinics.

PARTICIPANTS

In total, 15,428 active duty service members who completed 24,162 NSI questionnaires between March 2009 and May 2020.

DESIGN

Observational retrospective analysis of questionnaires collected as part of standard clinical care.

MAIN MEASURES

NSI, Post-Traumatic Stress Disorder Checklist for DSM-5 and Military Version, Patient Health Questionnaire (PHQ), Generalized Anxiety Disorder, Headache Impact Test (HIT-6), Insomnia Severity Index (ISI), Epworth Sleepiness Scale (ESS), Activities-Specific Balance Confidence Scale (ABC), Dizziness Handicap Inventory (DHI), Alcohol Use Disorders Identification Test (AUDIT), and the World Health Organization Quality of Life Instrument-Abbreviated Version. Only questionnaires completed on the same date as the NSI were examined.

RESULTS

The total NSI score was moderately to strongly correlated with all questionnaires except for the AUDIT. The strongest correlation was between the NSI Affective Score and the PHQ9 (r  = 0.86). The NSI Vestibular Score was moderately correlated with the ABC (r = -0.55) and strongly correlated with the DHI (r = 0.77). At the item level, the HIT-6 showed strong correlation with NSI headache (r = 0.80), the ISI was strongly correlated with NSI difficulty sleeping (r = 0.63), and the ESS was moderately correlated with NSI fatigue (r = 0.39).

CONCLUSION

Clinicians and healthcare administrators can use the correlations reported in this study to determine if questionnaires add incremental value for their clinic as well as to make more informed decisions regarding which questionnaires to administer.

Characterization of Million Veteran Program (MVP) enrollees with Comprehensive Traumatic Brain Injury Evaluation (CTBIE) data: An analysis of neurobehavioral symptoms

The purpose of this study was to examine neurobehavioral symptom reporting in a large sample of military veterans (N = 12,144) who completed the Comprehensive Traumatic Brain Injury Evaluation (CTBIE) and enrolled in the VA's Million Veteran Program (MVP). The CTBIE is a clinician-administered interview that assesses for historical, deployment-related traumatic brain injury (TBI) and evaluates symptoms using the Neurobehavioral Symptom Inventory (NSI). Clinicians completing the CTBIE made clinical determinations about participants' (1) TBI diagnostic status (i.e., CTBIE+ or CTBIE-) and (2) current symptom etiology (i.e., Symptom Resolution, TBI, Behavioral Health, Comorbid TBI + Behavioral Health [Comorbid], or Other). We evaluated the association of TBI diagnostic status and symptom etiology group with neurobehavioral symptoms. Results showed a significant association between TBI diagnostic status and all NSI variables, with CTBIE+ veterans endorsing greater symptoms than CTBIE- veterans. There was also a significant association between symptom etiology group and all NSI variables; specifically, the Comorbid and Behavioral Health groups generally endorsed significantly greater symptoms compared to the other groups. Follow-up analyses showed that relative to the Symptom Resolution group, the Comorbid and Behavioral Health groups had increased odds of severe/very severe cognitive and affective symptoms, whereas the TBI and Other groups did not. Finally, presence of psychiatric symptoms, pain, post-traumatic amnesia, loss of consciousness, and blast exposure significantly predicted Comorbid symptom etiology group membership. Findings from this large epidemiologic MVP study have relevant clinical implications and further highlight the importance of prioritizing integrated behavioral health interventions for this vulnerable population.

Impact of Prior Brain Injury on Concussion Recovery in Military Personnel: Evaluation of Timing Between Concussions

OBJECTIVE

To evaluate the potential impact of timing between the current and the most recent previous concussions on symptom severity among acutely concussed active duty military Service members (SMs).

SETTING

Three military installations.

PARTICIPANTS

Eighty-four SMs aged 18 to 44 years who sustained a concussion within 72 hours of enrollment. No previous concussion within 1 year preenrollment.

DESIGN

Longitudinal study with enrollment within 72 hours of injury, and follow-up at 1 week and 1 month postinjury.

MAIN MEASURES

Lifetime concussion history (yes/no) and recency of the latest concussion (no history, relatively more recent [1 to <6 years ago], and more remote [6+ years ago]) from the current concussion using the Ohio State University Traumatic Brain Injury Identification Method-Interview Form. Symptom severity (total and by categories: cognitive, affective, somatosensory, vestibular) at all time points using the Neurobehavioral Symptoms Inventory.

RESULTS

Concussion history assessed as having any previous concussion was not found significantly related to symptom severity (total or by categories) following a current concussion. However, when timing between concussion was taken into account, time since previous concussion was significantly related to symptomatology, whereby those with relatively more recent previous concussion had greater total symptoms within 72 hours of injury and at 1 week postinjury (though not at 1 month) than those with more remote previous concussion (≤72 hours: difference = 15.4, 95% CI = 1.8 to 29.1; 1 week: difference = 15.2, 95% CI = 1.2 to 29.2) or no history (≤72 hours: difference = 11.6, 95% CI = 0.4 to 22.8; 1 week: difference = 13.9, 95% CI = 2.4 to 25.4). When evaluated by symptom category, this relationship was particularly important on affective and somatosensory symptoms.

CONCLUSION

In recently concussed active duty SMs, the timing between the current and previous concussions may be an important factor in determining prognosis. Clinical assessment of concussion history that accounts for the timing of the most recent event may be necessary to identify patients who may require a more conservative plan of care and more gradual return to activity in the acute recovery stage.

Associations Among PTSD and Postconcussive Symptoms in the Long-Term Impact of Military-Relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium Prospective, Longitudinal Study Cohort

OBJECTIVE

To describe rates of mild traumatic brain injury (mTBI) with and without concurrent posttraumatic stress disorder a sample of former and current military personnel, and to compare the factor structure of the Neurobehavioral Symptom Inventory (NSI) based on whether participants sustained mTBI with and without a positive posttraumatic stress disorder (PTSD) screen.

SETTING

Participants recruited and tested at 7 Veterans Affairs (VA) sites and 1 military training facility as part of a national, longitudinal study of mental health, physical, and cognitive outcomes among veterans and service members. Participants: Total of 1540 former and current military personnel with a history of combat exposure.

DESIGN

Cross-sectional analysis of observational data, including confirmatory factor analysis. Main Measures: NSI and PTSD Checklist for DSM-5 (PCL-5).

RESULTS

Most participants (81.5%) had a history of mTBI and almost half of these screened positive for PTSD (40.5%); only 23.9% of participants without a history of mTBI screened positive for PTSD. Participants with a history of mTBI reported higher elevations of NSI and PCL-5 symptoms compared with those without a history of mTBI. Confirmatory factor analyses of the NSI demonstrated good model fit using a 4-factor structure (somatosensory, affective, cognitive, and vestibular symptoms) among groups of participants both with and without a history of mTBI.

CONCLUSION

Symptoms of mTBI and PTSD are strongly associated with each other among veterans and service members with a history of combat exposure. The 4-factor NSI structure is supported among participants with and without a history of mTBI. These findings suggest the potential benefit of a holistic approach to evaluation and treatment of veterans and service members with concurrent and elevated postconcussive and posttraumatic stress symptoms.

Neurobehavioral Symptoms in U.S. Special Operations Forces in Rehabilitation After Traumatic Brain Injury: A TBI Model Systems Study

INTRODUCTION

Special Operations Forces (SOF) personnel are at increased risk for traumatic brain injury (TBI), when compared with conventional forces (CF). Prior studies of TBI in military samples have not typically investigated SOF vs. CF as specific subgroups, despite documented differences in premorbid resilience and post-injury comorbidity burden. The aim of the current study was to compare SOF vs. CF on the presence of neurobehavioral symptoms after TBI, as well as factors influencing perception of symptom intensity.

MATERIALS AND METHODS

This study conducted an analysis of the prospective veterans affairs (VA) TBI Model Systems Cohort, which includes service members and veterans (SM/V) who received inpatient rehabilitation for TBI at one of the five VA Polytrauma Rehabilitation Centers. Of those with known SOF status (N = 342), 129 participants identified as SOF (average age = 43 years, 98% male) and 213 identified as CF (average age = 38.7 years, 91% male). SOF vs. CF were compared on demographics, injury characteristics, and psychological and behavioral health symptoms. These variables were then used to predict neurobehavioral symptom severity in univariable and multivariable analyses.

RESULTS

SOF personnel reported significantly greater posttraumatic stress disorder (PTSD) symptoms but less alcohol and drug use than the CF. SOF also reported greater neurobehavioral symptoms. When examining those with TBIs of all severities, SOF status was not associated with neurobehavioral symptom severity, while race, mechanism of TBI, and PTSD symptoms were. When examining only those with mTBI, SOF status was associated with lower neurobehavioral symptoms, while PTSD severity, white race, and certain mechanisms of injury were associated with greater neurobehavioral symptoms.

CONCLUSIONS

Among those receiving inpatient treatment for TBI, SOF SM/V reported higher neurobehavioral and symptom severity. PTSD was the strongest predictor of neurobehavioral symptoms and should be considered an important treatment target in both SOF and CF with co-morbid PTSD/TBI. A proactive human performance approach towards identification and treatment of psychological and neurobehavioral symptoms is recommended for SOF.

White Matter Hyperintensities Are Not Related to Symptomatology or Cognitive Functioning in Service Members with a Remote History of Traumatic Brain Injury

This study aimed to determine whether magnetic resonance imaging (MRI) white matter hyperintensities (WMHs) are associated with symptom reporting and/or cognitive performance in 1202 active-duty service members with prior single or multiple mild traumatic brain injury (mTBI). Patients with mTBI evaluated at the National Intrepid Center of Excellence (NICoE) at Walter Reed National Military Medical Center (WRNMMC) were divided into those with (n = 632) and without (n = 570) WMHs. The groups were compared on several self-report scales including the Neurobehavioral Symptom Inventory (NSI), Post-Traumatic Stress Disorder (PTSD) Checklist-Civilian Version (PCL-C), Satisfaction with Life Scale (SWLS), and Short Form-36 Health Survey (SF-36). They were also compared on several neuropsychological measures, including tests of attention, working memory, learning and memory, executive functioning, and psychomotor functioning. After correction for multiple comparisons, there were no significant differences between the two groups on any self-reported symptom scale or cognitive test. When comparing a subgroup with the highest (20+) WMH burden (n = 60) with those with no WMHs (n = 60; matched on age, education, sex, race, rank, and TBI number), only SF-36 Health Change significantly differed between the subgroups; the multiple WMH subgroup reported worsening health over the past year (t[53] = 3.52, p = 0.001, d = 0.67) compared with the no WMH subgroup. These findings build on prior research suggesting total WMHs are not associated with significant changes in self-reported symptoms or cognitive performance in patients with a remote history of mTBI. As such, clinicians are encouraged to use caution when reporting such imaging findings.

Patient Attribution of Posttraumatic Symptoms to Brain Injury Versus PTSD in Military-Related Mild TBI

OBJECTIVE

Persistent cognitive, somatic, and neuropsychiatric symptoms following mild traumatic brain injury (TBI) are influenced by posttraumatic stress disorder (PTSD), particularly in military patients. The authors evaluated the degree to which military service members with a history of mild TBI attributed posttraumatic symptoms to TBI versus PTSD.

METHODS

Service members (N=372) with mild TBI were surveyed about the severity of posttraumatic symptoms across four symptom clusters (cognitive, affective, somatosensory, and vestibular) with the Neurobehavioral Symptom Inventory (NSI). Participants rated the degree to which they believed TBI, PTSD, or other conditions contributed to their symptoms. Differences in cognitive, affective, somatosensory, and vestibular symptom severity were evaluated across participants with TBI, PTSD, or combined TBI-PTSD attribution. Logistic regression was used to evaluate the association between symptom profiles and attribution.

RESULTS

Participants attributed symptoms mostly to TBI, followed by insufficient sleep, PTSD, chronic pain, depression, and deployment-readjustment stress. PTSD and combined TBI-PTSD attribution were associated with higher total NSI scores (39.5 and 51.6, respectively), compared with TBI attribution only (31.4) (F=29.08, df=3, 358, p<0.01), as well as higher scores in every symptom category. More severe affective symptoms were associated with decreased odds of TBI attribution (odds ratio=0.90, 95% CI=0.83-0.97) and increased odds of PTSD attribution (odds ratio=1.14, 95% CI=1.03-1.26). A PTSD diagnosis was highly associated with PTSD attribution (odds ratio=2.44, 95% CI=1.07-5.58).

CONCLUSIONS

The nature and severity of posttraumatic symptoms appear to play a role in patient beliefs about the causes of symptoms, whether from TBI or PTSD.

FreeSurfer 5.3 versus 6.0: are volumes comparable? A Chronic Effects of Neurotrauma Consortium study

Automated neuroimaging methods like FreeSurfer ( https://surfer.nmr.mgh.harvard.edu/ ) have revolutionized quantitative neuroimaging analyses. Such analyses provide a variety of metrics used for image quantification, including magnetic resonance imaging (MRI) volumetrics. With the release of FreeSurfer version 6.0, it is important to assess its comparability to the widely-used previous version 5.3. The current study used data from the initial 249 participants in the ongoing Chronic Effects of Neurotrauma Consortium (CENC) multicenter observational study to compare the volumetric output of versions 5.3 and 6.0 across various regions of interest (ROI). In the current investigation, the following ROIs were examined: total intracranial volume, total white matter volume, total ventricular volume, total gray matter volume, and right and left volumes for the thalamus, pallidum, putamen, caudate, amygdala and hippocampus. Absolute ROI volumes derived from FreeSurfer 6.0 differed significantly from those obtained using version 5.3. We also employed a clinically-based evaluation strategy to compare both versions in their prediction of age-mediated volume reductions (or ventricular increase) in the aforementioned structures. Statistical comparison involved both general linear modeling (GLM) and random forest (RF) methods, where cross-validation error was significantly higher using segmentations from FreeSurfer version 5.3 versus version 6.0 (GLM: t = 4.97, df = 99, p value = 2.706e-06; RF: t = 4.85, df = 99, p value = 4.424e-06). Additionally, the relative importance of ROIs used to predict age using RFs differed between FreeSurfer versions, indicating substantial differences in the two versions. However, from the perspective of correlational analyses, fitted regression lines and their slopes were similar between the two versions, regardless of version used. While absolute volumes are not interchangeable between version 5.3 and 6.0, ROI correlational analyses appear to yield similar results, suggesting the interchangeability of ROI volume for correlational studies.

Development of the traumatic brain injury Rehabilitation Needs Survey: a Veterans Affairs TBI Model Systems study

PURPOSE

To describe the development of the Rehabilitation Needs Survey (RNS) for persons in the chronic phase of traumatic brain injury (TBI) recovery.

MATERIALS AND METHODS

RNS items were generated following a literature review (January - March 2015) on the topic of rehabilitation needs and revised via consensus from an expert panel of TBI clinicians and researchers. The RNS was added to the VA TBI Model Systems longitudinal study; data collection occurred between 2015-2019. Needs were classified as current (if endorsed) or absent; if current, needs were classified as unmet if no help was received. Need frequency and association with rehabilitation outcomes were presented.

RESULTS

Eight studies examined rehabilitation needs and formed the initial item pool of 42 needs. This was reduced to form the 21-item RNS which was administered at year 1 (n = 260) and year 2 (n = 297) post-TBI. Number of needs endorsed was 8-9, and number of unmet needs was 1-2, on average. Number of needs was correlated with functional status, neurobehavioral symptoms, and mental health symptoms (p < 0.05) suggesting support for convergent validity of the RNS.

CONCLUSION

The RNS is a new measure of rehabilitation needs following TBI. Further investigation into its psychometrics and clinical utility is recommended.Implications for rehabilitationVeterans and Service Members with traumatic brain injury across the severity spectrum have ongoing rehabilitation needs during the chronic phase of recovery.The Rehabilitation Needs Survey is a standardized measure of rehabilitation needs following traumatic brain injury.Identification of unmet rehabilitation needs is important for raising awareness of service gaps and providing justification for resource allocation.

Efficacy of an Interdisciplinary Intensive Outpatient Program in Treating Combat-Related Traumatic Brain Injury and Psychological Health Conditions

Background: Since 2000, over 413,000 US service members (SM) experienced at least one traumatic brain injury (TBI), and 40% of those with in-theater TBIs later screened positive for comorbid psychological health (PH) conditions, including post-traumatic stress disorder (PTSD), depression, and anxiety. Many SMs with these persistent symptoms fail to achieve a recovery that results in a desirable quality of life or return to full duty. Limited information exists though to guide treatment for SMs with a history of mild TBI (mTBI) and comorbid PH conditions. This report presents the methods and outcomes of an interdisciplinary intensive outpatient program (IOP) in the treatment of SMs with combat-related mTBI and PH comorbidities. The IOP combines conventional rehabilitation therapies and integrative medicine techniques with the goal of reducing morbidity in multiple neurological and behavioral health domains and enhancing military readiness. Methods: SMs (n = 1,456) with residual symptoms from mTBI and comorbid PH conditions were treated in a 4-week IOP at the National Intrepid Center of Excellence (NICoE) at Walter Reed National Military Medical Center (WRNMMC). The IOP uses an interdisciplinary, holistic, and patient-centric rehabilitative care model. Interdisciplinary teams provide a diagnostic workup of neurological, psychiatric, and existential injuries, and from these assessments, individualized care plans are developed. Treatment response was assessed using the Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Military Version (PCL-M), Satisfaction With Life Scale (SWLS), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Epworth Sleepiness Scale (ESS), and Headache Impact Test-6 (HIT-6) and administered at admission, discharge, and at 1, 3, and 6 months post-discharge. Findings: Following treatment in the IOP, the symptomatic patients had statistically significant and clinically meaningful improvements across all outcome measures. The largest effect size was seen with GAD-7 (r = 0.59), followed by PHQ-8 (r = 0.56), NSI (r = 0.55), PCL-M (r = 0.52), ESS (r = 0.50), SWLS (r = 0.49), and HIT-6 (r = 0.42). In cross-sectional follow ups, the significant improvements were sustained at 1, 3, and 6 months post-discharge. Interpretation: This report demonstrates that an interdisciplinary IOP achieves significant and sustainable symptom recovery in SMs with combat-related mTBI and comorbid PH conditions and supports the further study of this model of care in complex medical conditions.

The structure of post-concussion symptoms in adolescent student athletes: confirmatory factor analysis and measurement invariance

Objective: This study examined factor models for the Post-Concussion Symptom Scale (PCSS) at baseline and after suspected sport-related concussion, and measurement invariance from pre-injury to post-injury assessments and across age, gender, and health history groups (e.g., attention-deficit/hyperactivity disorder, psychiatric history). Methods: Adolescent student athletes (ages 13-18) completed a baseline PCSS (n = 39,015; 54.3% boys) and a subsample within 21 days of a suspected concussion (n = 1,554; 56.7% boys) completed a post-injury PCSS. Five models were evaluated for fit and invariance. Results: Confirmatory factor analyses showed good baseline and post-injury model fit for a previously supported four-factor model (i.e., cognitive-sensory, sleep-arousal, vestibular-somatic, and affective), an alternative four-factor model (i.e., cognitive, sleep-arousal, physical, and affective), and an incomplete bifactor model with vestibular-somatic and affective specific factors, along with partial invariance from pre-injury to post-injury assessments. Partial-to-full invariance was established for each model at baseline across demographic and health history groups. Conclusions: Results showed empirical and conceptual support for both PCSS subscales (i.e., cognitive, sleep-arousal, physical, and affective) and a total score for use in pre-injury to post-injury assessments and across demographic and health history groups at baseline. Future normative data, stratified by demographics and health history, could provide more precise symptom assessments for concussion management.

Interaction Between Psychiatric Symptoms and History of Mild TBI When Evaluating Postconcussion Syndrome in Veterans

INTRODUCTION

Symptoms of postconcussive syndrome (PCS) after mild TBI (mTBI) have been shown to resolve quickly, yet new research raises questions about possible long-term effects of this condition. It is not clear how best to address assessment and treatment when someone reports lingering symptoms of PCS. One self-report measure used by the VA and the DoD is the Neurobehavioral Symptom Inventory (NSI), but this measure may be affected by underlying psychiatric symptoms. We investigated whether the NSI is sensitive to mTBI after considering a number of psychiatric and demographic factors.

METHODS

This study examined which factors are associated with NSI scores in a Veteran sample (n = 741) that had recently returned from deployment.

RESULTS

Post-traumatic stress disorder (PTSD) and depression accounted for most of the variance on the NSI. Although history of mTBI was initially related to NSI, this association was no longer significant after other covariates were considered.

CONCLUSIONS

The NSI score was primarily explained by symptoms of PTSD and depression, suggesting that the NSI is not specific to the experience of a brain injury. We recommend cautious interpretation when this measure is used in the chronic phase after mTBI, especially among patients with comorbid depression or PTSD.

Provider Training in the Management of Headache Following Concussion Clinical Recommendation: Promoting a Standardized Means for Efficient Patient Recovery and Timely Return to Duty

Background: Headache is a common symptom reported following concussion/mild traumatic brain injury. The Department of Defense's clinical recommendation (CR) describes guidance for primary care providers for the management of post-traumatic headache (PTH) in Service members.

Objective: The objective of this study is to examine the association between training on the CR with provider clinical practice, patient behaviors, and symptom recovery.

Methods: Participants were healthcare providers and two patient groups (one receiving care as usual [CAU] and another receiving care after provider training on PTH CR [CR+]). Providers were interviewed at three time points: (1) prior to CAU enrollment; (2) after CAU enrollment, but prior to training; and (3) after CR+ follow-up. Data from the second and third provider interview were used to evaluate a potential difference between provider practices pre- and post-training (n = 13). Patients were enrolled within 6 months of concussion. Patient outcomes (including neurobehavioral and headache symptoms) were assessed at three time-points: within 72 h (n = 35), at 1-week (n = 34) and at 1-month post-enrollment (n = 27).

Results: Most follow-up care reported by providers were recommended within 72 h of initial visit post-training vs. >1 week pre-training. Additionally, providers reported a greater number of visits based on patient symptoms after training than before. Post-training, most providers reported referring patients to higher level of care “as needed,” if not “very rarely,” compared to 25% reported referrals prior to training. At 1-week post-enrollment the CR+ patient group reported more frequent medical provider visits compared to the CAU group. This trend was reversed at the 1-month follow-up whereby more CAU reported seeing a medical provider compared to CR+. By 1-week post-enrollment, fewer patients in the CR+ group reported being referred to any other providers or specialists compared to the CAU group. No differences in patient outcomes by provider training was found.

Conclusion: The study results demonstrate the feasibility of training on the Management of Headache Following Concussion CR in order to change provider practices by promoting timely care, and promoting patient compliance as shown through improvement in follow-up visits and more monitoring within the primary care clinic.

Post-concussive symptom endorsement and symptom attribution following remote mild traumatic brain injury in combat-exposed Veterans: An exploratory study

The purpose of this study was to examine rates of and relationships between "post-concussive" symptom endorsement and symptom attribution in Veterans with a history of mild traumatic brain injury (mTBI). This cross-sectional, exploratory study included 48 combat-exposed Iraq/Afghanistan Veterans with remote history of mTBI. All Veterans completed clinical interviews and self-report questionnaires assessing sociodemographic factors, injury and combat-related variables, psychiatric distress, self-efficacy, and coping style. To assess symptom endorsement and symptom attribution, a modified version of the Neurobehavioral Symptom Inventory was administered. Results showed that the most commonly endorsed "post-concussive" symptoms were several non-specific symptoms, while the symptoms most frequently attributed to mTBI included forgetfulness, poor concentration, and headaches. Furthermore, although there were some overlapping correlates of both symptom endorsement and symptom attribution, unique variables were associated with each domain. Specifically, symptom endorsement was uniquely associated with measures of psychiatric distress, while symptom attribution was uniquely associated with having a history of loss of consciousness and a greater degree of combat exposure. Taken together, results suggest that endorsement of symptoms may be significantly impacted by the presence of mental health comorbidities, but that perceptions or beliefs as to why symptoms are occurring are related more to mTBI and combat-related characteristics. Findings offer potential avenues for therapeutic intervention, emphasize the importance of psychoeducation, and highlight the need to consider using alternate terminology for these symptoms that promotes recovery and minimizes misattribution of symptoms.

Unmet Rehabilitation Needs Indirectly Influence Life Satisfaction 5 Years After Traumatic Brain Injury: A Veterans Affairs TBI Model Systems Study

OBJECTIVE

To describe the association between unmet rehabilitation needs and life satisfaction 5 years after traumatic brain injury (TBI).

DESIGN

Prospective observational cohort.

SETTING

Five Veterans Affairs (VA) Polytrauma Rehabilitation Centers.

PARTICIPANTS

VA TBI Model Systems participants (N=301); 95% male; 77% white; average age, 39±14y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Satisfaction With Life Scale (SWLS).

RESULTS

Average SWLS score was 22±8. Univariable analyses demonstrated several statistically significant predictors of life satisfaction, including employment status, participation, psychiatric symptom severity, past year mental health treatment, and total number of unmet rehabilitation needs (all P<.05). Multivariable analyses revealed that depression and participation were each associated with life satisfaction. An ad hoc mediation model suggested that unmet rehabilitation needs total was indirectly related to life satisfaction. Total unmet rehabilitation needs ranged from 0-21 (mean, 2.0±3.4). Correlational analyses showed that 14 of the 21 unmet rehabilitation needs were associated with life satisfaction.

CONCLUSIONS

Findings support the need for rehabilitation engagement in later stages of TBI recovery. Ongoing assessment of and intervention for unmet rehabilitation needs in the chronic phase of recovery have the potential to mitigate decline in life satisfaction.

Meningeal blood-brain barrier disruption in acute traumatic brain injury

The meninges serve as a functional barrier surrounding the brain, critical to the immune response, and can be compromised following head trauma. Meningeal enhancement can be detected on contrast-enhanced MRI in patients presenting with acute traumatic brain injury, even when head CT is negative. Following head trauma, gadolinium-based contrast appears to extravasate from the vasculature, enhancing the dura within minutes, and later permeates the subarachnoid space. The aims of this study were to characterize the initial kinetics of the uptake of contrast agent after injury and the delayed redistribution of contrast enhancement in the subarachnoid space in hyperacute patients. Neuroimaging was obtained prospectively in two large ongoing observational studies of patients aged 18 years or older presenting to the emergency department with suspected acute head injury. Dynamic contrast-enhanced MRI studies in a cohort of consecutively enrolling patients with mild traumatic brain injury (n = 36) determined that the kinetic half-life of dural-related meningeal enhancement was 1.3 ± 0.6 min (95% enhancement within 6 min). The extravasation of contrast into the subarachnoid space was investigated in a cohort of CT negative mild traumatic brain injury patients initially imaged within 6 h of injury (hyperacute) who subsequently underwent a delayed MRI, with no additional contrast administration, several hours after the initial MRI. Of the 32 patients with delayed post-contrast imaging, 18 (56%) had conspicuous expansion of the contrast enhancement into the subarachnoid space, predominantly along the falx and superior sagittal sinus. Patients negative for traumatic meningeal enhancement on initial hyperacute MRI continued to have no evidence of meningeal enhancement on the delayed MRI. These studies demonstrate that (i) the initial enhancement of the traumatically injured meninges occurs within minutes of contrast injection, suggesting highly permeable meningeal vasculature, and that (ii) contrast in the meninges redistributes within the subarachnoid space over the period of hours, suggesting a compromise in the blood-brain and/or blood-cerebrospinal barriers. Data from the parent study indicate that up to one in two patients with mild traumatic brain injury have traumatic brain injury on acute (<48 h) MRI, with a higher prevalence seen in patients with moderate or severe traumatic brain injury. The current study's findings of traumatic meningeal enhancement and the subsequent delayed extravasation of contrast into the subarachnoid spaces indicate that a substantial percentage of patients with even mild traumatic brain injury may have a transient disruption in barriers separating the vasculature from the brain.

Bifactor Model of the Sport Concussion Assessment Tool Symptom Checklist: Replication and Invariance Across Time in the CARE Consortium Sample

BACKGROUND

Identifying separate dimensions of concussion symptoms may inform a precision medicine approach to treatment. It was previously reported that a bifactor model identified distinct acute postconcussion symptom dimensions.

PURPOSE

To replicate previous findings of a bifactor structure of concussion symptoms in the Concussion Assessment Research and Education (CARE) Consortium sample, examine measurement invariance from pre- to postinjury, and evaluate whether factors are associated with other clinical and biomarker measures.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

Collegiate athletes were prospectively evaluated using the Sport Concussion Assessment Tool-3 (SCAT-3) during preseason (N = 31,557); 2789 were followed at <6 hours and 24 to 48 hours after concussion. Item-level SCAT-3 ratings were analyzed using exploratory and confirmatory factor analyses. Bifactor and higher-order models were compared for their fit and interpretability. Measurement invariance tested the stability of the identified factor structure across time. The association between factors and criterion measures (clinical and blood-based markers of concussion severity, symptom duration) was evaluated.

RESULTS

The optimal structure for each time point was a 7-factor bifactor model: a General factor, on which all items loaded, and 6 specific factors-Vestibulo-ocular, Headache, Sensory, Fatigue, Cognitive, and Emotional. The model manifested strict invariance across the 2 postinjury time points but only configural invariance from baseline to postinjury. From <6 to 24-48 hours, some dimensions increased in severity (Sensory, Fatigue, Emotional), while others decreased (General, Headache, Vestibulo-ocular). The factors correlated with differing clinical and biomarker criterion measures and showed differing patterns of association with symptom duration at different time points.

CONCLUSION

Bifactor modeling supported the predominant unidimensionality of concussion symptoms while revealing multidimensional properties, including a large dominant General factor and 6 independent factors: Headache, Vestibulo-ocular, Sensory, Cognitive, Fatigue, and Emotional. Unlike the widely used SCAT-3 symptom severity score, which declines gradually after injury, the bifactor model revealed separable symptom dimensions that have distinct trajectories in the acute postinjury period and different patterns of association with other markers of injury severity and outcome.

CLINICAL RELEVANCE

The SCAT-3 total score remains a valuable, robust index of overall concussion symptom severity, and the specific factors identified may inform management strategies. Because some symptom dimensions continue to worsen in the first 24 to 48 hours after injury (ie, Sensory, Fatigue, Emotional), routine follow-up in this time frame may be valuable to ensure that symptoms are managed effectively.