Discriminating Mild Traumatic Brain Injury and Posttraumatic Stress Disorder Using Latent Neuroimaging and Neuropsychological Profiles in Active-Duty Military Service Members.

OBJECTIVE: Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) commonly occur among military Service Members and Veterans and have heterogenous, but also overlapping symptom presentations, which often complicate the diagnoses of underlying impairments and development of effective treatment plans. Thus, we sought to examine whether the combination of whole brain gray matter (GM) and white matter (WM) structural measures with neuropsychological performance can aid in the classification of military personnel with mTBI and PTSD. METHODS: Active-Duty US Service Members ( n = 156; 87.8% male) with a history of mTBI, PTSD, combined mTBI+PTSD, or orthopedic injury completed a neuropsychological battery and T1- and diffusion-weighted structural neuroimaging. Cortical, subcortical, ventricular, and WM volumes and whole brain fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were calculated. Latent profile analyses were performed to determine how the GM and WM indicators, together with neuropsychological indicators, classified individuals. RESULTS: For both GM and WM, respectively, a 4-profile model was the best fit. The GM model identified greater ventricular volumes in Service Members with cognitive symptoms, including those with a diagnosis of mTBI, either alone or with PTSD. The WM model identified reduced FA and elevated RD in those with psychological symptoms, including those with PTSD or mTBI and comorbid PTSD. However, contrary to expectation, a global neural signature unique to those with comorbid mTBI and PTSD was not identified. CONCLUSIONS: The findings demonstrate that neuropsychological performance alone is more robust in differentiating Active-Duty Service Members with mTBI and PTSD, whereas global neuroimaging measures do not reliably differentiate between these groups.

Neurobehavioral Symptom Inventory Item-Level Change Complements the Reliable Change Method.

OBJECTIVE: To determine correspondence between the statistically derived 8-point reliable change index for the Neurobehavioral Symptom Inventory (NSI) against clinically significant item-level change in symptom severity from intake to discharge for mild traumatic brain injury (mTBI). SETTING: Brain Injury Rehabilitation Service at Brooke Army Medical Center, Fort Sam Houston, San Antonio, Texas. PATIENTS: In total, 655 active-duty service members with a diagnosis of mTBI who received treatment and completed self-report measures between 2007 and 2020. DESIGN: Observational retrospective analysis of outpatient clinical outcomes data. MAIN MEASURES: NSI total score change was used to divide patients into responder and nonresponders based on whether they met an 8-point decrease between intake and discharge. In addition, patients who had at least one NSI item that changed from a rating of 3 (severe) or 4 (very severe) at intake to a rating of 0 (none) or 1 (mild) at discharge were coded as an individual with significant item-level change. RESULTS: Forty-five percent of the sample had significant item-level change and were classified as responders according to the reliable change method. Eight percent of the sample had significant item-level change but did not meet the 8-point reliable change threshold. Fifteen percent of the sample did not experience significant item-level change but were classified as responders according to reliable change. Thirty-one percent did not meet either method's criterion for change. Classification agreement between the reliable change and item-level change methods was 76%, which was statistically significant ( = 181.32, P < .001). CONCLUSION: There is good correspondence between reliable change and item-level change on the NSI in this population. Reliable change is easily calculated and thus much more accessible than the item-level change method. There may be some situations where calculating item-level change may be helpful.

NSI and PCL-5 Normative Tables for Active Duty Service Members Affected by Traumatic Brain Injury.

INTRODUCTION: Many service members (SMs) have been diagnosed with traumatic brain injury. Currently, military treatment facilities do not have access to established normative tables which can assist clinicians in gauging and comparing patient-reported symptoms. The aim of this study is to provide average scores for both the Neurobehavioral Symptom Inventory (NSI) and Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) for active duty SMs based upon varying demographic groups. METHODS: Average scores were calculated for both the NSI and PCL-5 surveys from SMs who attended a military outpatient traumatic brain injury clinic. For this analysis, only the initial surveys for each SM were considered. The identifying demographics included age group, gender, grade, and race. RESULTS: Four normative tables were created to show the average scores of both the NSI and PCL-5 surveys grouped by demographics. The tables are grouped by Age Group/Gender/Race and Grade/Gender/Race. CONCLUSION: Clinicians and healthcare administrators can use the scores reported in this study to determine where SM NSI or PCL-5 scores fall within the average for their demographic group.

Comparing resting-state connectivity of working memory networks in U.S. Service members with mild traumatic brain injury and posttraumatic stress disorder.

Mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) are prevalent among military populations, and both have been associated with working memory (WM) impairments. Previous resting-state functional connectivity (rsFC) research conducted separately in PTSD and mTBI populations suggests that there may be similar and distinct abnormalities in WM-related networks. However, no studies have compared rsFC of WM brain regions in participants with mTBI versus PTSD. We used resting-state fMRI to investigate rsFC of WM networks in U.S. Service Members (n = 127; ages 18-59) with mTBI only (n = 46), PTSD only (n = 24), and an orthopedically injured (OI) control group (n = 57). We conducted voxelwise rsFC analyses with WM brain regions to test for differences in WM network connectivity in mTBI versus PTSD. Results revealed reduced rsFC between ventrolateral prefrontal cortex (vlPFC), lateral premotor cortex, and dorsolateral prefrontal cortex (dlPFC) WM regions and brain regions in the dorsal attention and somatomotor networks in both mTBI and PTSD groups versus controls. When compared to those with mTBI, individuals with PTSD had lower rsFC between both the lateral premotor WM seed region and middle occipital gyrus as well as between the dlPFC WM seed region and paracentral lobule. Interestingly, only vlPFC connectivity was significantly associated with WM performance across the samples. In conclusion, we found primarily overlapping patterns of reduced rsFC in WM brain regions in both mTBI and PTSD groups. Our finding of decreased vlPFC connectivity associated with WM is consistent with previous clinical and neuroimaging studies. Overall, these results provide support for shared neural substrates of WM in individuals with either mTBI or PTSD.

Research Letter: Long-Term Outcomes Following Cognitive Rehabilitation for Mild Traumatic Brain Injury: A 5-Year Follow-Up of a Cohort From the SCORE Randomized Clinical Trial.

OBJECTIVE: To examine the functioning of military service members 5 years after completing a randomized controlled trial (RCT) of cognitive rehabilitation for mild traumatic brain injury (mTBI). SETTING: Home-based telephonic interview and internet-based self-ratings. PARTICIPANTS: Sixty-nine of the 126 (55%) active-duty service members who were enrolled in a 4-arm RCT of cognitive rehabilitation 3 to 24 months after mTBI and were successfully contacted by phone 5 years later. Original and 5-year follow-up participants in each of 4 RCT treatment arms included: psychoeducation ( n = 32 original, n = 17 follow-up), computer ( n = 30 original, n = 11 follow-up), therapist-directed ( n = 30 original, n = 23 follow-up), integrated ( n = 34 original, n = 18 follow-up). DESIGN: Inception cohort evaluated 5 years after completion of an RCT of cognitive rehabilitation. MAIN MEASURES: Postconcussion symptoms (Neurobehavioral Symptom Inventory total score), psychological distress (Symptom Checklist-90-revised Global Severity Index score), and functional cognitive/behavioral symptoms (Key Behaviors Change Inventory total average score). RESULTS: Participants' postconcussive symptoms and psychological distress improved at the 5-year follow-up. Functional cognitive/behavioral symptoms were not significantly improved, but therapeutic gains were maintained across time, to 5 years after completing the RCT. CONCLUSION: In this sample of military personnel, postconcussive symptoms and psychological distress significantly improved from posttreatment to 5 years after cognitive rehabilitation, regardless of treatment arm. Functional cognitive/behavioral symptoms significantly improved with treatment while treatment gains were maintained at the 5-year follow-up. Replication of these results with a larger sample and interim data between 18 weeks and 5 years post-treatment is needed.

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.

Latent Neuropsychological Profiles to Discriminate Mild Traumatic Brain Injury and Posttraumatic Stress Disorder in Active-Duty Service Members.

OBJECTIVE: To determine whether cognitive and psychological symptom profiles differentiate clinical diagnostic classifications (eg, history of mild traumatic brain injury [mTBI] and posttraumatic stress disorder [PTSD]) in military personnel. METHODS: US Active-Duty Service Members ( N = 209, 89% male) with a history of mTBI ( n = 56), current PTSD ( n = 23), combined mTBI + PTSD ( n = 70), or orthopedic injury controls ( n = 60) completed a neuropsychological battery assessing cognitive and psychological functioning. Latent profile analysis was performed to determine how neuropsychological outcomes of individuals clustered together. Diagnostic classifications (ie, mTBI, PTSD, mTBI + PTSD, and orthopedic injury controls) within each symptom profile were examined. RESULTS: A 5-profile model had the best fit. The profiles differentiated subgroups with high (34.0%) or normal (21.5%) cognitive and psychological functioning, cognitive symptoms (19.1%), psychological symptoms (15.3%), and combined cognitive and psychological symptoms (10.0%). The symptom profiles differentiated participants as would generally be expected. Participants with PTSD were mainly represented in the psychological symptom subgroup, while orthopedic injury controls were mainly represented in the high-functioning subgroup. Further, approximately 79% of participants with comorbid mTBI and PTSD were represented in a symptomatic group (∼24% = cognitive symptoms, ∼29% = psychological symptoms, and 26% = combined cognitive/psychological symptoms). Our results also showed that approximately 70% of military personnel with a history of mTBI were represented in the high- and normal-functioning groups. CONCLUSIONS: These results demonstrate both overlapping and heterogeneous symptom and performance profiles in military personnel with a history of mTBI, PTSD, and/or mTBI + PTSD. The overlapping profiles may underscore why these diagnoses are often difficult to diagnose and treat, but suggest that advanced statistical models may aid in identifying profiles representing symptom and cognitive performance impairments within patient groups and enable identification of more effective treatment targets.

The management and rehabilitation of post-acute mild traumatic brain injury.

DESCRIPTION: In June 2021, the U.S. Department of Veterans Affairs (VA) and U.S. Department of Defense (DoD) approved a joint clinical practice guideline for the management and rehabilitation care for those who have symptoms in the post-acute period following mild traumatic brain injury (mTBI). This synopsis describes some of the clinically important recommendations. METHODS: In January 2020, VA and DoD leaders assembled a joint VA/DoD guideline development team of multidisciplinary clinical stakeholders that developed key questions, systematically searched and evaluated the literature, created two 1-page algorithms, and refined 19 recommendations using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The process closely conformed to the National Academy of Medicine's tenets for trustworthy clinical practice guidelines. RECOMMENDATIONS: This synopsis describes clinically important recommendations for the management and rehabilitation of mTBI. Outpatient primary care providers are the target audience for this synopsis and guideline. The current recommendations are an update from the 2016 VA/DoD Clinical Practice Guidelines for the Management of Concussion-Mild Traumatic Brain Injury.

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.

Elevated Kinesiophobia Is Associated With Reduced Recovery From Lower Extremity Musculoskeletal Injuries in Military and Civilian Cohorts.

OBJECTIVE: The purpose of this study was to examine associations between level of kinesiophobia and improvement in physical function during recovery from lower extremity injury. METHODS: A total 430 adults (mean [SD]: age = 27.3 [6.4] years; sex = 70.5% men; body mass index = 27.6 [5.2] kg/m2) were included in the analyses. Using the Patient-Reported Outcomes Measurement Information System, physical function was evaluated in parallel with treatment from a physical therapist at the initial visit and every 3 weeks until final visit or up to 6 months. A Tampa Scale of Kinesiophobia (TSK-17) score of >41 indicated elevated TSK. Four TSK groups were identified: (1) TSK score improved from >41 at initial visit to <41 by final visit (TSK_I), (2) TSK score was <41 at initial and final visits (TSK-), (3) TSK score was >41 at initial and final visits (TSK+), and (4) TSK score worsened from <41 at initial visit to ≥41 by final visit (TSK_W). Linear mixed effects models were used to examine differences between groups in improved physical function over time, with adjustment for depression and self-efficacy. RESULTS: Groups with elevated kinesiophobia at the final visit had smaller positive improvements in physical function (mean change [95% CI]: TSK+ = 7.1 [4.8-9.4]; TSK_W: 6.0 [2.6-9.4]) compared with groups without elevated kinesiophobia at the final visit (TSK_I = 9.8 [6.4-13.3]; TSK- = 9.7 [8.1-11.3]) by 12 weeks. CONCLUSIONS: Elevated kinesiophobia that persists or develops over the course of care is associated with less improvement in physical function within military and civilian cohorts. IMPACT: The findings of this prospective longitudinal study support the need to assess for elevated kinesiophobia throughout the course of care because of its association with decreased improvement in physical function. LAY SUMMARY: To help improve your physical function, your physical therapist can monitor the interaction between fear of movement and your clinical outcomes over the course of treatment.

Distinct patterns of resting-state connectivity in U.S. service members with mild traumatic brain injury versus posttraumatic stress disorder.

Mild traumatic brain injury (mTBI) is highly prevalent in military populations, with many service members suffering from long-term symptoms. Posttraumatic stress disorder (PTSD) often co-occurs with mTBI and predicts worse clinical outcomes. Functional neuroimaging research suggests there are both overlapping and distinct patterns of resting-state functional connectivity (rsFC) in mTBI versus PTSD. However, few studies have directly compared rsFC of cortical networks in military service members with these two conditions. In the present study, U.S. service members (n = 137; ages 19-59; 120 male) underwent resting-state fMRI scans. Participants were divided into three study groups: mTBI only, PTSD only, and orthopedically injured (OI) controls. Analyses investigated group differences in rsFC for cortical networks: default mode (DMN), frontoparietal (FPN), salience, somatosensory, motor, auditory, and visual. Analyses were family-wise error (FWE) cluster-corrected and Bonferroni-corrected for number of network seeds regions at the whole brain level (pFWE < 0.002). Both mTBI and PTSD groups had reduced rsFC for DMN and FPN regions compared with OI controls. These group differences were largely driven by diminished connectivity in the PTSD group. rsFC with the middle frontal gyrus of the FPN was increased in mTBI, but decreased in PTSD. Overall, these results suggest that PTSD symptoms may have a more consistent signal than mTBI. Our novel findings of opposite patterns of connectivity with lateral prefrontal cortex highlight a potential biomarker that could be used to differentiate between these conditions.

Number of Concussions Does Not Affect Treatment Response to Cognitive Rehabilitation Interventions Following Mild TBI in Military Service Members.

OBJECTIVE: The study objective was to determine whether number of concussions would affect symptom improvement following cognitive rehabilitation (CR) interventions. METHOD: Service members (N = 126) with concussion history completed a 6-week randomized control trial of CR interventions. Participants were stratified based on self-reported lifetime concussion frequency. Outcome measures included the Paced Auditory Serial Addition Test (PASAT), the Global Severity Index (GSI) from the Symptom Checklist-90-Revised, and the Key Behaviors Change Inventory (KBCI). RESULTS: Mixed-model analyses of variance revealed a significant main effect for time on cognitive, psychological, and neurobehavioral functioning. A significant main effect for the number of concussions was observed for GSI and KBCI, but not PASAT. Interactions between the number of concussions and time were not significant for any of the outcome variables. CONCLUSIONS: Over the 6-week interval, improvements were found for all participants across all outcome measures. Number of concussions did not affect improvements over time.

Self-efficacy predicts response to cognitive rehabilitation in military service members with post-concussive symptoms.

This study examined whether self-efficacy differentiated treatment responders from non-responders in a trial of cognitive rehabilitation (CR) for postconcussive symptoms. 126 service members with mild TBI seen on average 9.5 months since injury completed one of four cognitive rehabilitation treatments for 6 weeks. The four treatment arms were: (1) Psychoeducation control, (2) Self-administered computerized CR, (3) Interdisciplinary CR, and (4) Interdisciplinary CR integrated with CBT. Outcome was assessed across time (baseline, and 6, 12, and 18 weeks post-treatment) for three domains: psychological (Symptom Checklist-90-Revised; SCL-90-R), cognitive (Paced Auditory Serial Addition Test; PASAT), and functional/behavioural (Key Behaviors Change Inventory; KBCI). Mixed model ANOVAs tested for self-efficacy differences across time in treatment responders versus non-responders, as defined by reliable change indices. A significant interaction was found on the SCL-90 such that responders had increasing self-efficacy with respect to psychological symptoms across four time points, whereas non-responders' self-efficacy did not change. Perceived self-efficacy at the beginning of treatment was associated with treatment engagement within the psychological domain for responders only, suggesting a mediating role in treatment outcome. Overall, results suggest that increasing patients' level of self-efficacy may be important for successful treatment of psychological distress in those with remote concussion.

Single-Item Versus Multiple-Item Headache Ratings in Service Members Seeking Treatment for Brain Injury.

INTRODUCTION: Headaches are the most common complaint after traumatic brain injury (TBI) and a significant cause of morbidity and disability among military personnel. Currently, there are a several measures which can assess headache disability, but there is a significant burden to assess each individual symptom given this heterogeneous polymorbid population. The objective of this proposed study was to validate the single headache item from the Neurobehavioral Symptom Inventory (NSI) compared to the 6-item Headache Impact Test (HIT-6). MATERIALS AND METHODS: Participants included consecutive treatment-seeking outpatients at the Brain Injury Rehabilitation Service at the Brooke Army Medical Center from August 2007 to January 2010 who were administered a battery of assessment measures at initial intake, as part of usual care. Archival record review was conducted using procedures approved by the local Institutional Review Board. Inclusionary criteria included completion of both the HIT-6 and NSI. Participants with a cut-off score of >22 on the NSI Validity-10 were excluded in a post hoc analysis to validate findings among those who passed validity screen. RESULTS: The Pearson correlation between the single-item NSI headache measure and the HIT-6 revealed at least 64% shared variance in this military sample (r = 0.8, p < 0.001), indication a high association between the two measures. CONCLUSION: The NSI single-item headache measure adequately captured headache severity in this military cohort. Use of the single-item NSI headache measure may minimize survey burden on participants whose primary complaint is not headaches, or who present with multiple symptoms. Future studies are needed to validate the single-item headache measure in other samples.

The Management of Stroke Rehabilitation: A Synopsis of the 2019 U.S. Department of Veterans Affairs and U.S. Department of Defense Clinical Practice Guideline.

Description: In June 2019, the U.S. Department of Veterans Affairs (VA) and U.S. Department of Defense (DoD) approved an update of the joint clinical practice guideline for rehabilitation after stroke. This synopsis summarizes the key recommendations from this guideline. Methods: In February 2018, the VA/DoD Evidence-Based Practice Work Group convened a joint VA/DoD guideline development effort that included clinical stakeholders and stroke survivors and conformed to the National Academy of Medicine (formerly the Institute of Medicine) tenets for trustworthy clinical practice guidelines. The guideline panel identified key questions, systematically searched and evaluated the literature, and developed 2 algorithms and 42 key recommendations using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. Stroke survivors and their family members were invited to share their perspectives to further inform guideline development. Recommendations: The guideline recommendations provide evidence-based guidance for the rehabilitation care of patients after stroke. The recommendations are applicable to health care providers in both primary care and rehabilitation. Key features of the guideline are recommendations in 6 areas: timing and approach; motor therapy; dysphagia; cognitive, speech, and sensory therapy; mental health therapy; and other functions, such as returning to work and driving.

Rehabilitation of Cognitive Dysfunction Following Traumatic Brain Injury.

This article outlines key principles and considerations in the rehabilitation of cognitive challenges following mild, moderate, and severe traumatic brain injuries, with a focus on the needs of the service member and veteran population. The authors highlight specific evidence-based strategies and interventions and provide functional examples to support implementation. By emphasizing the array of tools and resources that have been designed to address cognitive challenges in the service member and veteran population, they focus on optimizing cognition to support successful community reintegration and the resumption of a full and meaningful life.

Reconceptualizing rehabilitation of individuals with chronic symptoms following mild traumatic brain injury.

PURPOSE/OBJECTIVE: Effective treatment for postconcussive symptoms (PCS) immediately following mild traumatic brain injury (mTBI) includes reassurance, support, education about mTBI, and symptom management. However, effective treatments for chronic postconcussive-like symptoms, particularly with mental health comorbidities, remain unclear. Research Method/Design: We conduct a critical review of the treatment literature for chronic PCS, present exemplar studies of two alternative treatment approaches (i.e., cognitive rehabilitation (CR) and psychotherapy with various cognitive-behavioral therapy (CBT) approaches) and compare their relative effectiveness, and examine other literature to compare treatment benefits of one approach over another. RESULTS: This review and comparisons found CBT approaches to be 5 to 6 times more potent in reducing chronic PCS than CR. CONCLUSIONS/IMPLICATIONS: Based on these findings we encourage rehabilitation professionals to "re-conceptualize" the factors that likely underlie chronic PCS and the most effective treatment for this condition. We propose that CBT interventions focusing on comorbid and underlying mental health issues should be an essential, not adjunctive, treatment approach for chronic PCS. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Subcortical shape and neuropsychological function among U.S. service members with mild traumatic brain injury.

In a recent manuscript, our group demonstrated shape differences in the thalamus, nucleus accumbens, and amygdala in a cohort of U.S. Service Members with mild traumatic brain injury (mTBI). Given the significant role these structures play in cognitive function, this study directly examined the relationship between shape metrics and neuropsychological performance. The imaging and neuropsychological data from 135 post-deployed United States Service Members from two groups (mTBI and orthopedic injured) were examined. Two shape features modeling local deformations in thickness (RD) and surface area (JD) were defined vertex-wise on parametric mesh-representations of 7 bilateral subcortical gray matter structures. Linear regression was used to model associations between subcortical morphometry and neuropsychological performance as a function of either TBI status or, among TBI patients, subjective reporting of initial concussion severity (CS). Results demonstrated several significant group-by-cognition relationships with shape metrics across multiple cognitive domains including processing speed, memory, and executive function. Higher processing speed was robustly associated with more dilation of caudate surface area among patients with mTBI who reported more than one CS variables (loss of consciousness (LOC), alteration of consciousness (AOC), and/or post-traumatic amnesia (PTA)). These significant patterns indicate the importance of subcortical structures in cognitive performance and support a growing functional neuroanatomical literature in TBI and other neurologic disorders. However, prospective research will be required before exact directional evolution and progression of shape can be understood and utilized in predicting or tracking cognitive outcomes in this patient population.

Predicting treatment response to cognitive rehabilitation in military service members with mild traumatic brain injury.

OBJECTIVE: Determine factors that affect responsiveness to cognitive rehabilitation (CR) interventions in service members (SMs) who sustained mild traumatic brain injury (mTBI). METHOD: 126 SMs with a history of mTBI 3 to 24 months postinjury participated in a randomized clinical trial of one of four, 6-week treatment arms: (a) psychoeducation, (b) computer-based CR, (c) therapist-directed manualized CR, and (d) therapist-directed CR integrated with cognitive-behavioral psychotherapy. Practice-adjusted reliable change scores (RCS) were calculated for the three primary outcome measures: Paced Auditory Serial Addition Test (PASAT), Symptom Checklist-90 Revised (SCL-90-R) Global Severity Index (GSI), and Key Behaviors Change Inventory (KBCI). Hierarchical logistic regression was used to predict RCS. Variables considered were: (a) demographic, (b) injury characteristics, (c) comorbid mental health conditions, (d) nonspecific treatment variables (i.e., team vs. no-team milieu), and (e) specific treatment elements. RESULTS: No predictor variables were associated with RCS improvements on the PASAT or the SCL-90-R. Comorbid depression (p < .02) and team-treatment milieu (p < .02) were associated with RCS improvement on the KBCI. Specific CR (ps > .65) and psychotherapy treatments (p > .26) were not associated with improvements on any outcome. There was evidence that self-administered computer CR was not only not beneficial, but negatively associated with cognitive and neurobehavioral improvement. CONCLUSIONS: Although reliable improvements were found on the PASAT and KBCI, no specific treatment intervention effects were found. Rather, comorbid depression and team-milieu treatment environment were associated with improvement, but only on the KBCI. Comorbid depression was associated with higher rates of improvement. (PsycINFO Database Record

Neuropsychological Performance and Subjective Symptom Reporting in Military Service Members With a History of Multiple Concussions: Comparison With a Single Concussion, Posttraumatic Stress Disorder, and Orthopedic Trauma.

OBJECTIVE: To examine differences in objective neurocognitive performance and subjective cognitive symptoms in individuals with a history of a single concussion, multiple concussions, orthopedic injuries, and posttraumatic stress disorder (PTSD). METHOD: Participants included 116 military service members who sustained a mild traumatic brain injury (mTBI) during combat deployment. Subjects were subdivided into groups based on concussion frequency: a single concussion (n = 42), 2 concussions (n = 21), and 3 or more concussions (n = 53). Eighty-one subjects sustained an orthopedic injury (n = 60) during deployment or were diagnosed with PTSD (n = 21), but had no history of mTBI. Subjects completed a battery of neuropsychological tests and self-report measures of postconcussive symptoms, PTSD symptoms, and psychopathology. RESULTS: No differences were found among the concussion groups on a composite neuropsychological measure. The PTSD group had the highest number of symptom complaints, with the 2-concussion and 3-plus-concussion groups being most similar to the PTSD group. The concussion groups showed a nonsignificant pattern of increasing distress with increasing number of concussions. CONCLUSIONS: The current findings are consistent with meta-analytic results showing no differential effect on neuropsychological functioning due to multiple concussions. Results also support the burden of adversity hypothesis suggesting increasing symptom levels with increasing psychological or physically traumatic exposures.