Plasma calcitonin gene-related peptide and nerve growth factor as headache and pain biomarkers in recently deployed soldiers with and without a recent concussion.

OBJECTIVE: The objective of this study was to characterize the utility of calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) as potential biomarkers for headache and pain disorders in the post-military deployment setting. BACKGROUND: The need to improve recognition, assessment, and prognoses of individuals with posttraumatic headache or other pain has increased interest in the potential of CGRP and NGF as biomarkers. METHODS: The Warrior Strong Study (NCT01847040) is an observational longitudinal study of United States-based soldiers who had recently returned from deployment to Afghanistan or Iraq from 2009 to 2014. The present nested cross-sectional analysis uses baseline data collected from soldiers returning to Fort Bragg, North Carolina. RESULTS: In total, 264 soldiers (mean (standard deviation [SD] age 28.1 [6.4] years, 230/264 [87.1%] men, 171/263 [65.0%] White) were analyzed. Mean (SD) plasma levels of CGRP were 1.3 (1.1) pg/mL and mean levels of NGF were 1.4 (0.4) pg/mL. Age was negatively correlated with NGF (-0.01 pg/mL per year, p = 0.007) but was not associated with CGRP. Men had higher mean (SD) CGRP plasma levels than women (1.4 95% confidence interval [CI; 1.2] vs. 0.9 95% CI [0.5] pg/mL, p < 0.002, Kruskal-Wallis test). CGRP levels were lower in participants who had a headache at the time of the blood draw (1.0 [0.6] pg/mL vs. 1.4 [1.2] pg/mL, p = 0.024). NGF was lower in participants with continuous pain (all types; 1.2 [0.4] vs. 1.4 [0.4] pg/mL, p = 0.027) and was lower in participants with traumatic brain injury (TBI) + posttraumatic headache (PTH) versus TBI without PTH (1.3 [0.3] vs. 1.4 [0.4] pg/mL, p = 0.021). Otherwise, CGRP and NGF were not associated with migraine-like headache, TBI status, or headache burden as measured by the number of medical encounters in crude or adjusted models. CONCLUSION: In this exploratory study, plasma levels of NGF and CGRP showed promise as biomarkers for headache and other types of pain. These findings need to be replicated in other cohorts.

Mild Traumatic Brain Injury in the Maturing Brain: An Investigation of Symptoms and Cognitive Performance in Soldiers Returning From Afghanistan and Iraq.

OBJECTIVE: The majority of traumatic brain injuries (TBIs) are classified as mild and occur in young individuals. The course of recovery varies but can result in chronic or troubling outcomes. The impact of age on TBI outcomes in young adults before complete brain maturation is not well studied. METHODS: In this study, we compared the effects of mild TBI on cognitive performance and self-reported TBI symptoms and posttraumatic stress disorder (PTSD) in 903 soldiers in 3 different age groups: 24 years or younger, 25 to 27 years, and 28 to 40 years. The soldiers had returned from war zones in Iraq and were screened for TBI within a few days of return. Cognitive performance was measured with the Automated Neuropsychological Assessment Metrics of Military TBI Version 4 (ANAM4). Symptoms associated with mild TBI were self-reported on the Neurobehavioral Symptom Inventory, and the PTSD Checklist-Civilian Version (PCL-C). RESULTS: Soldiers with TBI in every age group had significantly higher prevalence of most symptoms than those with no TBI. Soldiers with TBI also reported more chronic pain sites, regardless of age. Soldiers aged 28 to 40 years with TBI had the lowest cognitive performance scores (ANAM) across several subtests, both unadjusted and adjusted. The Global Deficit Score was significantly higher for soldiers aged 28 to 40 years and 25 to 27 years with TBI than for soldiers younger than 24 years with no TBI. After adjusting for PTSD symptoms, education, and number of lifetime TBIs, the overall test battery mean for soldiers aged 28 to 40 years with TBI was significantly lower than for soldiers younger than 24 years with no TBI. CONCLUSION: Soldiers with mild TBI in the younger age group show more symptoms associated to frontal lobe function while soldiers in the older group suffer more cognitive impairment. This may warrant further study as it may indicate a propensity to later cognitive decline among soldiers who were older at the time of injury.

Headache complexity (number of symptom features) differentiates post-traumatic from non-traumatic headaches.

BACKGROUND: Post-traumatic headaches are a common sequela of mild traumatic brain injury (concussion). It is unclear whether or how these headaches differ phenotypically from primary headaches. OBJECTIVE: Determine whether there is an overarching unobserved latent trait that drives the expression of observed features of post-traumatic headache and other headaches. METHODS: Data from this post-hoc analysis come from the Warrior Strong Cohort Study conducted from 2010 through 2015. Approximately 25,000 soldiers were screened for concussion history at routine post-deployment health assessments. A random sample was invited to participate, enrolling 1567. Twelve observed headache phenotypic features were used to measure "headache complexity", the latent trait of clinical interest, using single factor confirmatory factor analysis. We compared headache complexity between groups and determined whether headache complexity predicted accessing medical care for headache. RESULTS: Of 1094 soldiers with headaches, 198 were classified as having post-traumatic headache. These headaches were compared to those in the other soldiers (647 without concussion history and 249 with concussion history). Soldiers with post-traumatic headache had greater endorsement of all 12 headache features compared to the soldiers with non-concussive headaches. The confirmatory factor analysis showed good model fit (χ2 (51) = 95.59, p = 0.0002, RMSEA = 0.03, comparative fit index = 0.99, and Tucker-Lewis index = 0.99), providing empirical support for the headache complexity construct. Soldier groups differed in their mean headache complexity level (p < 0.001) such that post-traumatic headache soldiers had greater headache complexity compared to non-concussed soldiers (standardized mean difference = 0.91, 95% confidence interval: 0.72-1.09, p < 0.001 and to concussed soldiers with coincidental headaches standardized mean difference = 0.75, 95% confidence interval: 0.53-0.96, p < 0.001). Increasing headache complexity predicted medical encounters for headache (odds ratio = 1.87, 95% confidence interval: 1.49-2.35, p < 0.001) and migraine (odds ratio = 3.74, 95% confidence interval: 2.33-5.98, p < 0.001) during the year following deployment.Conclusions and relevance: The current study provided support for a single latent trait, characterized by observed headache symptoms, that differentiates between concussive and non-concussive headaches and predicts use of medical care for headache. The single trait confirmatory factor analysis suggests that post-traumatic headaches differ from non-concussive headaches by severity more than kind, based on the symptoms assessed.ClinicalTrials.gov identifier NCT01847040.

Estimates of Long-Term Disability Among US Service Members With Traumatic Brain Injuries.

BACKGROUND: Traumatic brain injury (TBI) is a significant health issue in the US military. The purpose of this study was to estimate the probability of long-term disability among hospitalized service members (SMs) with TBIs, using the South Carolina Traumatic Brain Injury and Follow-up Registry (SCTBIFR) model developed on civilian hospitalized patients. METHODS: We identified military patients in military or civilian hospitals or theater level 3 to 5 military treatment facilities (MTFs) whose first TBI occurred between October 1, 2013, and September 30, 2015. TBI-related disability at 1-year post-hospital discharge was estimated using regression coefficients from the SCTBIFR. RESULTS: Among the identified 4877 SMs, an estimated 65.6% of SMs with severe TBI, 56.2% with penetrating TBI, 31.4% with moderate TBI, and 12.0% with mild TBI are predicted to develop long-term disability. TBI patients identified at theater level 4 and 5 MTFs had an average long-term disability rate of 56.9% and 61.1%, respectively. In total, we estimate that 25.2% of all SMs hospitalized with TBI will develop long-term disability. CONCLUSION: Applying SCTBIFR long-term probability estimates to US SMs with TBIs provides useful disability estimates to inform providers and health systems on the likelihood that particular subgroups of TBI patients will require continued support and long-term care.

"We didn't forget" Utilizing a Community-Nurse Partnership to Promote Health in Rockport, Texas after Hurricane Harvey.

BACKGROUND: On August 25th 2017 Harvey, a category 4 hurricane, made landfall on the south coast of Texas with heavy winds and rain that severely damaged the seaside town of Rockport. The challenge facing healthcare providers following a natural disaster is timely assessments of community need and available resources. One week later, faculty at the University of Texas Health Science Center San Antonio, School of Nursing (SON) completed a community assessment and developed valuable partnerships. AIMS: Eighteen days after the initial assessment, faculty had secured support from The Children's Health Fund and operationalized strategies to provide disaster relief and experiential learning opportunities for the SON Population Focused Health undergraduate students. MATERIALS & METHODS: The community-as-partner model served as the framework to apply the nursing process to a community in crisis. As the focus shifted to recovery, the team prioritized the need to address long-term consequences for children after a natural disaster. RESULTS: Two educational sessions were designed using an interactive and instructional approach to discuss parental strategies to assess and support children as they navigated through loss after Harvey. DISCUSSION: This community-nurse partnership has endured, and the SON faculty and students continue to travel to Rockport to promote health and provide education to the community.

Trajectory of Postconcussive Symptoms 12 Months After Deployment in Soldiers With and Without Mild Traumatic Brain Injury: Warrior Strong Study.

We analyzed data from a cohort of recently deployed soldiers from 2 US Army bases, Fort Carson and Fort Bragg (2009 to 2015). Soldiers with and without a recent history of mild traumatic brain injury (mTBI) on deployment were evaluated within days of return and at 3, 6, and 12 months. Those with mTBI were more likely than those without to endorse ≥1 postconcussive symptom as "severe" and/or "very severe" (47% vs. 21%, baseline; adjusted relative risk (RR) = 1.71, 95% confidence interval: 1.51, 1.93, all time points), which remained significant after adjusting for posttraumatic stress disorder (adjusted RR = 1.34, 95% confidence interval: 1.20, 1.50). Prevalence and relative risks for 3 of the most common baseline symptoms remained constant over time: sleep problems (RR = 2.19), forgetfulness (RR = 2.56), and irritability (RR = 2.73). The pattern was slightly different for headache (baseline, RR = 3.44; 12 months, RR = 3.26), due to increased prevalence of headache in those without mTBI. The prevalence of clinically relevant postconcussive symptoms remained relatively constant over 1 year of follow-up, whether or not symptoms were associated with concussion. Service members with recent mTBI reported more symptoms than those without at all time points.

A Clinical Evidence-Based Approach to Examine the Effects of mTBI and PTSD Symptoms on ANAM Performance in Recently Deployed Active Duty Soldiers: Results From the Warrior Strong Study.

OBJECTIVE: Service members are frequently diagnosed with comorbid mild traumatic brain injury (mTBI) and posttraumatic stress disorder after returning from Afghanistan and Iraq. Little is known about how mTBI in the postacute and chronic phases combined with current posttraumatic stress disorder symptoms (PTS) affects performance on the Automated Neuropsychological Assessment Metrics, Version 4, Traumatic Brain Injury-Military (ANAM4) battery used by the US military. We examined postdeployment ANAM4 performance using conventional statistical methods, as well as rates of poor performance, below established cutoffs (<10th and ≤2nd percentile). METHODS: A total of 868 soldiers were assessed for history of mTBI during the most recent deployment, as well as, lifetime mTBI, current PTS, and current pain-related symptoms. The ANAM4 was also administered. RESULTS: Soldiers with PTS and/or mTBI performed worse on ANAM4 relative to controls with those with both conditions performing worst. However, a nontrivial minority (∼10%-30%) of individuals with mTBI, PTS, or both had scores that were at or below the second percentile. CONCLUSION: Our results illustrate that a combination of mTBI and PTS is associated with worse ANAM4 performance than either condition alone. Furthermore, only a minority of soldiers with any, or both, of the conditions had ANAM deficits. The long-lasting impacts and unique contribution of each condition have yet to be determined.

Service needs and barriers to care five or more years after moderate to severe TBI among Veterans.

PRIMARY OBJECTIVE: The objective of this paper is to identify the most frequent service needs, factors associated with needs, and barriers to care among Veterans and service members five or more years after moderate to severe traumatic brain injury (TBI). RESEARCH DESIGN: Survey administered via telephone 5-16 years after injury (median eight years) and subsequent acute inpatient rehabilitation at a regional Veterans Affairs (VA) medical centre. METHODS AND PROCEDURES: Participants were 119 Veterans and military personnel, aged 23-70 (median 35), 90% male. Demographics, injury characteristics, service needs, whether needs were addressed, barriers to care, health and general functioning were assessed. MAIN OUTCOMES AND RESULTS: The most frequent needs were for help with memory, information about available services and managing stress. Obtaining information about services was the most consistently un-addressed need; managing stress was the most consistently addressed need. Cognitive and psychiatric symptoms and alienation from community were associated with needs going un-addressed. Participants treated after an expansion of TBI services at the study site reported fewer un-addressed needs. Not knowing where to get help was the most common barrier to care. CONCLUSION: Repeated outreach, assessment of needs and education about available services are needed throughout Veterans' lifespan after moderate to severe TBI.

Long-term outcomes after moderate-to-severe traumatic brain injury among military veterans: Successes and challenges.

OBJECTIVE: To assess long-term outcomes after traumatic brain injury (TBI) among veterans and service members. SETTING: Regional Veterans Affairs medical centre. PARTICIPANTS: One hundred and eighteen veterans and military personnel, aged 23-70 years (median = 35 years), 90% male, had moderate-to-severe TBI (82% in coma > 1 day, 85% amnesic > 7 days), followed by acute interdisciplinary rehabilitation 5-16 years ago (median = 8 years). DESIGN: Cross-sectional analysis of live interviews conducted via telephone. MAIN MEASURES: TBI follow-up interview (occupational, social, cognitive, neurologic and psychiatric ratings), Community Integration Questionnaire, Disability Rating Scale (four indices of independent function) and Satisfaction with Life Scale. RESULTS: At follow-up, 52% of participants were working or attending school; 34% ended or began marriages after TBI, but the overall proportion married changed little. Finally, 22% were still moderately-to-severely disabled. However, 62% of participants judged themselves to be as satisfied or more satisfied with life than before injury. Injury severity, especially post-traumatic amnesia, was correlated with poorer outcomes in all functional domains. CONCLUSIONS: After moderate-severe TBI, most veterans assume productive roles and are satisfied with life. However, widespread difficulties and functional limitations persist. These findings suggest that veteran and military healthcare systems should continue periodic, comprehensive follow-up evaluations long after moderate-to-severe TBI.

Fluorescence dye-based detection of mAb aggregates in CHO culture supernatants.

Product yields, efficacy, and safety of monoclonal antibodies (mAbs) are reduced by the formation of higher molecular weight aggregates during upstream processing. In-process characterization of mAb aggregate formation is a challenge since there is a lack of a fast detection method to identify mAb aggregates in cell culture. In this work, we present a rapid method to characterize mAb aggregate-containing Chinese hamster ovary (CHO) cell culture supernatants. The fluorescence dyes thioflavin T (ThT) and 4-4-bis-1-phenylamino-8-naphthalene sulfonate (Bis-ANS) enabled the detection of soluble as well as large mAb aggregates. Partial least square (PLS) regression models were used to evaluate the linearity of the dye-based mAb aggregate detection in buffer down to a mAb aggregate concentration of 2.4 µg mL(-1). Furthermore, mAb aggregates were detected in bioprocess medium using Bis-ANS and ThT. Dye binding to aggregates was stable for 60 min, making the method robust and reliable. Finally, the developed method using 10 µmol L(-1) Bis-ANS enabled discrimination between CHO cell culture supernatants containing different levels of mAb aggregates. The method can be adapted for high-throughput screening, e.g., to screen for cell culture conditions influencing mAb product quality, and hence can contribute to the improvement of production processes of biopharmaceuticals in mammalian cell culture.

Update on the Epidemiology of Concussion/Mild Traumatic Brain Injury.

Mild traumatic injuries to the brain (e.g., concussion) are common and have been recognized since antiquity, although definitions have varied historically. Nonetheless, studying the epidemiology of concussion helps clarify the overall importance, risk factors, and at-risk populations for this injury. The present review will focus on recent findings related to the epidemiology of concussion including definition controversies, incidence, and patterns in the population overall and in the military and athlete populations specifically. Finally, as this is an area of active research, we will discuss how future epidemiologic observations hold promise for gaining greater clarity about concussion and mild traumatic brain injury.

The experience, expression, and control of anger following traumatic brain injury in a military sample.

OBJECTIVE: To investigate the impact of traumatic brain injury (TBI) on the experience and expression of anger in a military sample. PARTICIPANTS: A total of 661 military personnel with a history of TBI and 1204 military personnel with no history of TBI. DESIGN: Cross-sectional, between-group design, using multivariate analysis of variance. MAIN MEASURE: State-Trait Anger Expression Inventory-2 (STAXI-2). RESULTS: Participants with a history of TBI had higher scores on the STAXI-2 than controls and were 2 to 3 times more likely than the participants in the control group to have at least 1 clinically significant elevation on the STAXI-2. Results suggested that greater time since injury (ie, months between TBI and assessment) was associated with lower scores on the STAXI-2 State Anger scale. CONCLUSION: Although the results do not take into account confounding psychiatric conditions and cannot address causality, they suggest that a history of TBI increases the risk of problems with the experience, expression, and control of anger. This bolsters the need for proper assessment of anger when evaluating TBI in a military cohort.

A Qualitative Study of Potential Suicide Risk Factors Among Operation Iraqi Freedom/Operation Enduring Freedom Soldiers Returning to the Continental United States (CONUS).

OBJECTIVE: A qualitative study among Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) Soldiers was conducted to explore potential constructs underlying suicide according to the interpersonal-psychological theory of suicide (IPTS); these include burdensomeness, failed belonging, and acquired capability. METHODS: Qualitative semistructured interviews were conducted with 68 Soldiers at 3 months post-OEF/OIF deployment. Soldiers were asked about changes in their experiences of pain, burdensomeness, and lack of belonging. The methodology employed was descriptive phenomenological. RESULTS: Transcripts were reviewed and themes related to the IPTS constructs emerged. Soldiers' postdeployment transition experiences included higher pain tolerance, chronic pain, emotional reactivity, emotional numbing and distancing, changes in physical functioning, combat guilt, discomfort with care seeking, and difficulties reintegrating into family and society. CONCLUSIONS: Findings highlight the utility of the IPTS in understanding precursors to suicide associated with transition from deployment, as well as treatment strategies that may reduce risk in Soldiers during reintegration.

Direct analysis of mAb aggregates in mammalian cell culture supernatant.

BACKGROUND: Protein aggregation during monoclonal antibody (mAb) production can occur in upstream and downstream processing (DSP). Current methods to determine aggregate formation during cell culture include size exclusion chromatography (SEC) with a previous affinity chromatography step in order to remove disturbing cell culture components. The pre-purification step itself can already influence protein aggregation and therefore does not necessarily reflect the real aggregate content present in cell culture. To analyze mAb aggregate formation directly in the supernatant of Chinese hamster ovary (CHO) cell culture, we established a protocol, which allows aggregate quantification using SEC, without a falsifying pre-purification step. RESULTS: The use of a 3 µm silica SEC column or a SEC column tailored for mAb aggregate analysis allows the separation of mAb monomer and aggregates from disturbing cell culture components, which enables aggregate determination directly in the supernatant. Antibody aggregate analysis of a mAb-producing CHO DG44 cell line demonstrated the feasibility of the method. Astonishingly, the supernatant of the CHO cells consisted of over 75% mAb dimer and larger oligomers, representing a substantially higher aggregate content than reported in literature so far. CONCLUSION: This study highlights that aggregate quantification directly in the cell culture supernatant using appropriate SEC columns with suitable mAb aggregate standards is feasible without falsification by previous affinity chromatography. Moreover, our results indicate that aggregate formation should be addressed directly in the cell culture and is not only a problem in DSP.

Self-awareness and neurobehavioral outcomes, 5 years or more after moderate to severe brain injury.

OBJECTIVE: To examine self-awareness 5 years or more after traumatic brain injury (TBI) and its relation to outcomes. PARTICIPANTS: Sixty-two adults with moderate to severe TBI and significant other (SO) informants (family or close friend). SETTING: Regional veterans medical center. MAIN MEASURES: TBI Follow-up Interview, Community Integration Questionnaire, Satisfaction with Life Scale, and Caregiver Burden Inventory. DESIGN: Five to 16 years after acute inpatient rehabilitation, separate staff contacted and interviewed subjects and SOs. Subject awareness was defined as inverse subject-SO discrepancy scores. RESULTS: Subjects significantly underreported neurologic symptoms and overreported their work and home functioning; their self-ratings of emotional distress and social functioning did not differ from SO ratings. Employment was associated with greater self-awareness of cognitive deficits, even after controlling for injury severity. Subjects' life-satisfaction was associated with better self-reported neurologic functioning, which frequently did not agree with SO ratings. Caregiver burden was worse as SOs perceived subjects as having worse symptoms and poorer work and social integration. CONCLUSIONS: Impaired self-awareness remains evident more than 5 years after TBI. People with TBI are more likely to gain employment when they are aware of their cognitive deficits and abilities. However, subjective quality of life, for subjects and SOs, was related to their own perception of the TBI outcomes.

Self-reported mild TBI and postconcussive symptoms in a peacetime active duty military population: effect of multiple TBI history versus single mild TBI.

OBJECTIVE: To investigate the potential cumulative impact of mild traumatic brain injury (MTBI) on postconcussive symptoms. PARTICIPANTS: A total of 224 active duty soldiers reporting MTBI within 1 year of testing. For 101, this MTBI was their only reported traumatic brain injury (TBI); 123 had sustained at least 1 additional MTBI during their lifetime. A No TBI control group (n = 224) was included for comparison. MAIN MEASURE: Self-report symptoms data via questionnaire. Within time since injury subgroups (≤3 months; Post-3 months), symptom endorsement (no symptoms, 1 or 2 symptoms, 3+ symptoms) among soldiers with 1 MTBI was compared with that of soldiers with 2 or more MTBIs. Injured soldiers' symptom endorsement was compared with that of soldiers who had not sustained a TBI. RESULTS: Among the recently injured (≤3 months), those with 2 or more MTBIs endorsed significantly more symptoms than those with 1 MTBI: 67% of soldiers with 2 or more MTBIs reported 3+ symptoms, versus 29% of One MTBI soldiers. Among Post-3 month soldiers, there were no significant differences between MTBI groups. Overall, soldiers with MTBI endorsed significantly more symptoms than those without TBI. CONCLUSION: Past experience of MTBI may be a risk factor for increased symptom difficulty for several months postinjury. Clinicians should ascertain lifetime history of brain injury when evaluating patients for MTBI.

The differential contributions of posttraumatic amnesia duration and time since injury in prediction of functional outcomes following moderate-to-severe traumatic brain injury.

OBJECTIVE: To examine the relative contributions of preinjury, injury severity, and acute postinjury variables in predicting outcomes at 1 year following moderate-severe traumatic brain injury (TBI). DESIGN: Secondary analysis of a prospective longitudinal cohort study. SETTING: Four Veterans Affairs Medical Center acute inpatient rehabilitation programs. PARTICIPANTS: Active duty military or veterans with a nonpenetrating moderate-to-severe TBI. MAIN OUTCOME MEASURES: Independent living status (N = 280) and work status (N = 248) at one year postinjury. RESULTS: Preinjury characteristics as a group accounted for the largest amount of variance in independent living status at 1 year; however, posttraumatic amnesia (PTA) uniquely explained the largest amount of variance (8.8%). Those with less than 60 days PTA were 9 times more likely to be independent; those with less than 30 days PTA were 3 times more likely to be independent. In contrast, acute postinjury characteristics accounted for the largest amount of variance in work status, with time to rehabilitation explaining the most unique variance (10.4%). Those with less than 48 days time to rehabilitation were 2.4 times more likely to be productive. CONCLUSIONS: This study highlights the differential contribution of variables in the prediction of 2 specific functional outcomes in a military sample, adding to our current body of knowledge to assist clinicians, patients and their families following TBI.

Influence of bodily injuries on symptom reporting following uncomplicated mild traumatic brain injury in US military service members.

OBJECTIVE: : To examine the relations among bodily injuries, traumatic stress, and postconcussion symptoms in a sample of combat-injured US service members who sustained a mild traumatic brain injury. PARTICIPANTS: : One hundred and thirty-seven service members evaluated and treated at Walter Reed Army Medical Center following medical evacuation from the combat theater of Operation Enduring Freedom and Operation Iraqi Freedom. All had sustained an uncomplicated mild traumatic brain injury and concurrent bodily injuries. PROCEDURE: : Participants completed 2 symptom checklists within 3 months of injury. Severity of bodily injuries was quantified with a modified version of the Injury Severity Score that excluded intracranial injuries (ISSmod). Participants were classified into 4 ISSmod groups: minor (n = 17), moderate (n = 48), serious (n = 40), severe/critical (n = 32). MAIN OUTCOME MEASURES: : Neurobehavioral Symptom Inventory (NBSI) and the Posttraumatic Stress Disorder Checklist-Civilian version (PCLC). RESULTS: : There was a significant negative association between ISSmod scores and the NBSI and PCLC total scores. There were significant main effects across the 4 groups for the NBSI and PCLC total scores. The highest NBSI and PCLC scores were consistently found in the ISSmod minor group, followed by the moderate, serious, and severe/critical groups. CONCLUSIONS: : While it might be expected that greater comorbid physical injuries would be associated with greater symptom burden, in this study as the severity of bodily injuries increased, symptom burden decreased. Hypothesized explanations include: underreporting of symptoms; increased peer support; disruption of fear conditioning due to acute morphine use; or delayed expression of symptoms.

Mild Traumatic Brain Injury and Postconcussive Symptom Endorsement: A Parallel Comparison Between Two Nonclinical Cohorts.

INTRODUCTION: The prevalence of mild traumatic brain injury (mTBI) is commonly estimated based on indirect metrics such as emergency department visits and self-reporting tools. The study of postconcussive symptoms faces similar challenges because of their unspecific character and indistinct causality. In this article, we compare two nonclinical, epidemiological studies that addressed these two elements and were performed within a relatively narrow period in the state of Colorado. MATERIALS AND METHODS: De-identified datasets were obtained from a random digit-dialed survey study conducted by the Craig Hospital and a study surveying soldiers returning from deployment by Defense and Veteran Traumatic Brain Injury Center. Information pertinent to participants' demographics, a history of mTBI, and symptom endorsement was extracted and homogenized in order to establish a parallel comparison between the populations of the two studies. RESULTS: From the 1,558 (Warrior Strong, 679; Craig Hospital, 879) records selected for analysis, 43% reported a history of at least one mTBI. The prevalence was significantly higher among individuals from the Defense and Veteran Traumatic Brain Injury Center study independent of gender or race. Repetitive injuries were reported by 15% of the total combined cohort and were more prevalent among males. Symptom endorsement was significantly higher in individuals with a positive history of mTBI, but over 80% of those with a negative history of mTBI endorsed at least one of the symptoms interrogated. Significant differences were observed between the military and the civilian populations in terms of the types and frequencies of the symptoms endorsed. CONCLUSIONS: The prevalence of mTBI and associated symptoms identified in the two study populations is higher than that of previously reported. This suggests that not all individuals sustaining concussion seek medical care and highlights the limitations of using clinical reports to assess such estimates. The lack of appropriate mechanisms to determine symptom presence and causality remains a challenge. However, the differences observed in symptom reporting between cohorts raise questions about the nature of the symptoms, the impact on the quality of life for different individuals, and the effects on military health and force readiness.