Amy O. Bowles

Association between combat stress and post-concussive symptom reporting in OEF/OIF service members with mild traumatic brain injuries

Objective: The relationship between combat stress and post-concussive symptoms in service members with mild traumatic brain injuries (mTBI) is poorly understood. It was hypothesized that the co-occurrence of combat stress would have a significant effect on the severity of post-concussive complaints, specifically on emotional and cognitive symptoms. Methods: Four hundred and seventy-two combat-deployed service members with mTBI completed self-report inventories of post-traumatic stress and post-concussive symptoms. Two groups were formed based on post-traumatic stress symptoms (High Combat Stress and Low Combat Stress). Results: A 3–8-fold increase in post-concussive symptoms was observed when comparing the High and Low Combat Stress Groups. Elevations in post-concussive symptom reporting were not limited to emotional and/or cognitive symptoms, but rather were inclusive of all measured post-concussive symptoms. Conclusions: The findings of the present study suggest that non-brain injury-related factors, such as high-levels of combat stress, may impact post-concussive symptom reporting in this population, further confounding the accuracy of the post-concussion syndrome (PCS) diagnosis. Considerable caution should be exercised in making the diagnosis of PCS in concussed service members with co-occurring combat-stress disorders.

Utility of the Mild Brain Injury Atypical Symptoms Scale as a Screening Measure for Symptom Over-Reporting in Operation Enduring Freedom/Operation Iraqi Freedom Service Members with Post-Concussive Complaints

Evaluation of post-deployment conditions such as post-concussive syndrome (PCS) and posttraumatic stress disorder (PTSD) frequently relies upon brief, self-report checklists which are face valid and highly susceptible to potential symptom validity issues such as symptom exaggeration. We investigated the psychometric prope1rties of a 5-item measure of symptom exaggeration (mild brain injury atypical symptoms [mBIAS] scale) embedded in commonly used PCS and PTSD screening instruments in a sample of 403 patients seen in a brain injury clinic at a large military medical center. Exploratory factor analysis, examining measures of posttraumatic stress, post-concussive symptoms, and symptom over-reporting revealed a 6-factor model with the mBIAS scale items representing a unique factor. Analysis of psychometric properties demonstrated that a score of 8 on the mBIAS was optimal for the detection of symptom over-reporting (sensitivity = 0.94, specificity = 0.92) and appears to be the most favorable cut score for interpretive use. The findings provide a strong initial support for the use of the mBIAS in post-deployment populations.

Relationship Between Mechanism of Injury and Neurocognitive Functioning in OEF/OIF Service Members With Mild Traumatic Brain Injuries

Military personnel deployed to combat theaters in Iraq and Afghanistan are at risk of sustaining mild traumatic brain injuries (mTBI) from causes such as improvised explosive devices, motor vehicle accidents, and falls. Despite the high incidence of mTBI in deployed personnel, questions remain about the effects of blast-related vs. non-blast-related mTBI on acute and long-term sequelae. This investigation is a retrospective review of service members who presented for evaluation of suspected mTBI and underwent neurocognitive screening evaluation, mTBI diagnosis was made by semistructured clinical interview. Only individuals in whom mechanism of injury could be determined (blast vs. non-blast) were included. Sixty individuals were included in the final sample: 32 with blast mTBI and 28 with non-blast mTBI. There were no differences between the blast-related and non-blast-related mTBI groups on age, time since injury, combat stress symptoms, or headache. Analysis of variance showed no significant between-group differences on any of the neurocognitive performance domains. Although speculation remains that the effects of primary blast exposure are unique, the results of this study are consistent with prior research suggesting that blast-related mTBI does not differ from other mechanisms of injury with respect to cognitive sequelae in the postacute phase.

Factors associated with neurocognitive performance in OIF/OEF servicemembers with postconcussive complaints in postdeployment clinical settings.

Cognitive difficulties are frequently reported by Operation Enduring Freedom /Operation Iraqi Freedom military personnel who sustained mild traumatic brain injuries (TBIs). The current study examined several potential factors that may contribute to self-reported cognitive difficulties in postdeployment clinical settings. Eighty-four subjects who sustained a mild or moderate TBI and reported cognitive difficulties underwent neurocognitive testing. Multiple regression analyses were used to determine the amount of variance in neurocognitive performance accounted for by the predictor variables (demographic, mechanism of injury, time since injury, headache severity, combat stress, postconcussive complaints, and effort/performance validity). The predictor variables collectively accounted for 51.7% of the variance in cognitive performance (F (8,72) = 11/99, p < 0.001). The most potent predictor of cognitive functioning was performance validity/effort, which uniquely accounted for 16.3% of the variance (p < 0.01). Self-reported symptom severity, including postconcussive complaints, combat stress, and headache intensity, accounted for 7.2% of the variance (p < 0.05). Demographic factors and injury characteristics, such as time since injury and mechanism of injury, were not significant predictive factors of cognitive performance. The findings of the current study underscore the need to include measurement of effort as part of neurocognitive evaluation in postdeployment settings when evaluating cognitive complaints associated with mild TBI.

Cognitive Rehabilitation for Military Service Members With Mild Traumatic Brain Injury: A Randomized Clinical Trial.

Objective: To compare cognitive rehabilitation (CR) interventions for mild traumatic brain injury (mTBI) with standard of care management, including psychoeducation and medical care for noncognitive symptoms. Setting: Military medical center. Participants: A total of 126 service members who received mTBI from 3 to 24 months before baseline evaluation and reported ongoing cognitive difficulties. Interventions: Randomized clinical trial with treatment outcomes assessed at baseline, 3-week, 6-week, 12-week, and 18-week follow-ups. Participants were randomly assigned to one of four 6-week treatment arms: (1) psychoeducation, (2) computer-based CR, (3) therapist-directed manualized CR, and (4) integrated therapist-directed CR combined with cognitive-behavioral psychotherapy (CBT). Treatment dosage was constant (10 h/wk) for intervention arms 2 to 4. Measures: Paced Auditory Serial Addition Test (PASAT); Symptom Checklist–90 Revised (SCL-90-R); Key Behaviors Change Inventory (KBCI). Results: No differences were noted between treatment arms on demographics, injury-related characteristics, or psychiatric comorbidity apart from education, with participants assigned to the computer arm having less education. Using mixed-model analysis of variance, all 4 treatment groups showed a significant improvement over time on the 3 primary outcome measures. Treatment groups showed equivalent improvement on the PASAT. The therapist-directed CR and integrated CR treatment groups had better KBCI outcomes compared with the psychoeducation group. Improvements on primary outcome measures during treatment were maintained at follow-up with no differences among arms. Conclusions: Both therapist-directed CR and integrated CR with CBT reduced functional cognitive symptoms in service members after mTBI beyond psychoeducation and medical management alone.

Utility of the Mayo-Portland adaptability inventory-4 for self-reported outcomes in a military sample with traumatic brain injury.

OBJECTIVE To investigate the psychometric properties of the Mayo-Portland Adaptability Inventory-4 (MPAI-4) obtained by self-report in a large sample of active duty military personnel with traumatic brain injury (TBI). DESIGN Consecutive cohort who completed the MPAI-4 as a part of a larger battery of clinical outcome measures at the time of intake to an outpatient brain injury clinic. SETTING Medical center. PARTICIPANTS Consecutively referred sample of active duty military personnel (N=404) who suffered predominantly mild (n=355), but also moderate (n=37) and severe (n=12), TBI. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE MPAI-4 RESULTS: Initial factor analysis suggested 2 salient dimensions. In subsequent analysis, the ratio of the first and second eigenvalues (6.84:1) and parallel analysis indicated sufficient unidimensionality in 26 retained items. Iterative Rasch analysis resulted in the rescaling of the measure and the removal of 5 additional items for poor fit. The items of the final 21-item Mayo-Portland Adaptability Inventory-military were locally independent, demonstrated monotonically increasing responses, adequately fit the item response model, and permitted the identification of nearly 5 statistically distinct levels of disability in the study population. Slight mistargeting of the population resulted in the global outcome, as measured by the Mayo-Portland Adaptability Inventory-military, tending to be less reflective of very mild levels of disability. CONCLUSIONS These data collected in a relatively large sample of active duty service members with TBI provide insight into the ability of patients to self-report functional impairment and the distinct effects of military deployment on outcome, providing important guidance for the meaningful measurement of outcome in this population.

Susceptibility Weighted Imaging and White Matter Abnormality Findings in Service Members With Persistent Cognitive Symptoms Following Mild Traumatic Brain Injury.

Mild traumatic brain injury (mTBI) is a major health concern among active duty service members and Veterans returning from combat operations, and it can result in variable clinical and cognitive outcomes. Identifying biomarkers that can improve diagnosis and prognostication has been at the forefront of recent research efforts. The purpose of this study was to compare the sensitivity and specificity of abnormalities identified using more traditional magnetic resonance imaging (MRI) sequences such as fluid attenuation inversion recovery (FLAIR) to more advanced MRI sequences such as susceptibility weighted imaging (SWI) among a cohort of active duty service members experiencing persistent cognitive symptoms after mTBI. One-hundred and fifty-two active duty service members (77 mTBI, 58 orthopedically injured [OI] only, 17 post-traumatic stress disorder [PTSD] only) underwent MRI and neuropsychological evaluation at a large military treatment facility. Results demonstrated that FLAIR white matter hyperintensities (WMHs) were present in all three groups at statistically similar rates (41% mTBI, 49% OI, and 29% PTSD). With the exception of a single OI participant showing a small discrete SWI lesion, SWI abnormalities were overwhelmingly present in mTBI patients (22% mTBI, 1% OI, and 0% PTSD). Functionally, mTBI participants with and without SWI abnormalities did not differ in demographics, symptom reporting, or cognitive performance. However, mTBI participants with and without WMH did differ for on measures of working memory with the mTBI participants with WMH having worse cognitive performance. No other significant differences were noted for those participants with and without imaging abnormalities for either the OI or PTSD only cohorts. These results appear to illustrate the sensitivity and specificity of SWI findings though these results did not have any significant functional impact in this cohort. In contrast, WMHs noted on FLAIR imaging were not sensitive or specific findings, but functionally relevant among mTBI participants. These findings emphasize the complexity of injury and functional outcome in mTBI patients that requires additional examination.

Completion of Multidisciplinary Treatment for Persistent Postconcussive Symptoms Is Associated With Reduced Symptom Burden.

Objective: To investigate the pre- to posttreatment changes in both posttraumatic stress disorder (PTSD) and persistent postconcussive symptoms (PPCSs). Setting and Participants: We studied 257 active-duty patients with a history of mild traumatic brain injury (mTBI) who completed multidisciplinary outpatient treatment at Brooke Army Medical Center TBI Clinic from 2008 to 2013. This treatment program included cognitive rehabilitation; vestibular interventions; headache management; and integrated behavioral healthcare to address co-occurring psychiatric conditions such as PTSD, depression, and sleep disturbance. Design: A 1-group; preexperimental, pre- to posttreatment study. Main Measures: The Neurobehavioral Symptom Inventory (NSI) was used to assess PPCSs, and the PTSD Checklist–Military Version (PCL-M) was used to asses PTSD symptoms. Results: Global PPCS resolution (mean NSI: 35.0 pre vs 23.8 post; P < .0001; d = 0.72) and PTSD symptom resolution (mean PCL-M: 43.2 pre vs 37.7 post; P < .0001; d = 0.34) were statistically significant. Compared with those with only mTBI, patients with mTBI and PTSD reported greater global PPCS impairment both pretreatment (mean NSI: 48.7 vs 27.9; P < .0001) and posttreatment (mean NSI: 36.2 vs 17.4; P < .0001). After adjusting for pretreatment NSI scores, patients with comorbid PTSD reported poorer PPCS resolution than those with mTBI alone (mean NSI: 27.9 pre vs 21.7 post; P = .0009). Conclusion: We found a reduction in both self-reported PPCSs and PTSD symptoms; however, future studies are needed to identify specific components of care associated with symptom reduction.