Academic adjustments and concussion recoveries in NCAA student-athletes: a LIMBIC MATARS investigation.

OBJECTIVE: The aim of this study was to investigate the association between academic adjustments and recovery from sport-related concussions (SRCs) in collegiate athletes. MATERIALS AND METHODS: A retrospective medical chart review was performed between the 2015-2016 and 2019-2020 sport seasons at 11 Long-term Impact of Military-relevant Brain Injury Consortium Military and Tactical Athlete Research Study (LIMBIC MATARS) sites. Days between injury and symptom resolution, and injury and return to sport (dependent variables) for collegiate athletes who did or did not receive academic adjustments (independent variable) were analyzed using Mann-Whitney U tests. RESULTS: The number of days between date of injury and symptom-resolution between those who did (median = 9 [interquartile range = 5,16]) and did not have (7[3,12]) academic adjustments were statistically different (z=-2.76, p < 0.01, r=-0.17). However, no differences were observed between days to return to sport among those who did (14[10,22]) and did not (13[8,20]) receive assigned academic adjustments (z= -1.66, p = 0.10, r= -.10). CONCLUSIONS: Recovery trajectories were similar between athletes diagnosed with a SRC who did or did not receive academic adjustments.. Our findings suggest academic adjustments supported recovery for those who needed academic adjustments. Clinicians and healthcare professionals should assist and support collegiate athletes after SRCs on an individual basis, including academic adjustments when appropriate based on patient presentation.

Influence of sleep symptoms on recovery from concussion in collegiate athletes: a LIMBIC MATARS consortium investigation.

OBJECTIVE: Changes in sleep quality and quantity are commonly endorsed by individuals following a concussion. Limited data exists examining the role of sleep disturbances within 72 hours, and throughout recovery, from concussion. The objective of this study was to determine if the number of days to symptom resolution varied between collegiate athletes with or without sleep-related symptoms following a concussion. DESIGN: Retrospective chart review. METHODS: Collegiate athletes (n = 539) who were diagnosed with a concussion between the 2015-2020 sport seasons participated in this retrospective chart review. Participants were divided into groups based on the presence or absence of sleep symptoms within 72 hours of a diagnosed concussion. A Mann-Whitney U test was used to compare days to symptom resolution between groups with α = 0.05. RESULTS: Of the 539 participants, 250 (46.3%) reported sleep-related symptoms. Participants with sleep-related symptoms took significantly longer (U = 30656, p = 0.002) to report symptom resolution at rest (median [full range] = 8.00[0-423]) as compared to participants who did not report sleep-related symptoms (6.00[0-243] days). CONCLUSION: Collegiate athletes that report sleep-related symptoms immediately following concussion (<72 hours) were observed to take, on median, two days longer to achieve symptom resolution at rest when compared to athletes who did not endorse the same symptoms.

Exploring the relationship between contraceptive medication use and concussion recovery in female collegiate athletes: a LIMBIC MATARS consortium investigation.

OBJECTIVE: While recovery from concussion is variable, women are more likely to report symptoms, experience worse outcomes, and have longer recovery trajectories following concussion than men. Preliminary data suggest that hormonal fluctuations, specifically progesterone, may be associated with this variability. This study aimed to understand the effect of contraceptive medication on concussion recovery. METHODS: A retrospective chart review using consensus-based common data elements was conducted at 11 NCAA institutions as part of the LIMBIC MATARS consortium. Participants included female collegiate athletes diagnosed with a concussion who did (n = 117) or did not report (n = 339) contraceptive medication use. Number of days between diagnosis and symptom resolution were compared using Mann-Whitney U tests. Self-reported diagnosis of attention deficit hyperactivity disorder, concussion history, anxiety, and depression was compared using Chi-squared tests. RESULTS: The proportions of participants who did or did not take contraceptive medication were similar across covariates. Female athletes regardless of contraceptive medication use recovered similarly following a concussion. CONCLUSIONS: Our findings suggest that contraceptive medication use did not significantly impact concussion recovery. Future prospective investigations should examine documentation practices and operationalize terminology for hormonal contraceptive medication to better understand their role on recovery from sport-related concussion in female collegiate athletes.

The influence of ADHD on recovery from sport concussion among collegiate athletes in the United States: LIMBIC MATARS consortium investigation.

OBJECTIVE: The present study aimed to assess the potential influence of a diagnosis of ADHD on concussion recovery among collegiate athletes. DESIGN: Retrospective and cross-sectional. METHODS: Data were extracted retrospectively from medical records across LIMBIC MATARS member institutions (n = 11), representing 1,044 concussion cases among collegiate athletes. After exclusions, 406 concussions were included in our analysis (ADHD: n = 38, age = 20.2 ± 1.67 years, 18.4% female; No ADHD: n = 368, age = 19.8 ± 1.39 years, 40.1% female). Mann-Whitney U tests were used to compare days from injury to diagnosis, symptom resolution, and return to sport among athletes with and without ADHD. RESULTS: No differences were observed for days from concussion until diagnosis (z = -0.33, p = 0.74), until days to symptom resolution (z = -1.30, p = 0.19), or days until return to sport (z = -0.68, p = 0.49); among concussion cases with or without a previously reported diagnosis of ADHD. CONCLUSION: Our findings further expand the literature that suggests ADHD is not strongly associated with recovery trajectory following sport concussion in collegiate athletes. Future research should extend these findings to be inclusive of additional preexisting health conditions and moderating effects related to medication usage among diverse athlete levels.

Access to athletic trainers and sex as modifiers of time to reach clinical milestones after sport-related concussion in collegiate athletes.

OBJECTIVE: Investigate whether an athlete's biological sex and exposure to a dedicated athletic trainer (AT) were related to clinical milestones after a sports-related concussion (SRC). DESIGN: Retrospective chart review. METHODS: Medical charts of collegiate athletes (n = 196 [70.9% female]) diagnosed with SRC were reviewed to extract: biological sex, dedicated AT exposure for their sport (yes/no), and time (days) to reaching clinical milestones (diagnosis, symptom resolution, unrestricted return to sport [RTS]). Mann-Whitney U tests were used to determine whether time to clinical milestones differed by sex, AT exposure, or their interaction. Proportions of same-day diagnoses and times to diagnosis, symptom resolution, and unrestricted RTS were evaluated with chi-squared and spearman's rank correlations, respectively. RESULTS: There were no significant differences in times to reaching any clinical milestone by sex, AT exposure, or their interaction (ps > 0.05). Forty-three percent of participants were diagnosed on the day of their SRC. This did not differ by sex or AT exposure (ps > 0.29). Longer times to SRC diagnosis were associated with more days to symptom resolution (ρ = 0.236, p = 0.001) and unrestricted RTS (ρ = 0.223, p < 0.001). CONCLUSIONS: Athlete sex and AT exposure were not associated with times to reach any clinical milestone; however, delayed diagnosis was associated with longer times to reach clinical recovery.

Concussion diagnosis and recovery in relation to collegiate athletic department classification: a LIMBIC MATARS consortium investigation.

PURPOSE: We investigated time to reach concussion diagnosis and recovery milestones in collegiate athletes relative to their schools' National Collegiate Athletic Association (NCAA) classification. METHODS: We retrospectively examined 849 (43.1% female) concussion cases from 11 NCAA institutions (Division I Power 5 [n = 4], Division I Non-Power 5 [n = 4], and Division II/III [n = 3]) from the 2015-16 to 2019-20 athletic seasons. Our primary outcome measures were days to reach specific clinical milestones following concussion. RESULTS: Median (IQR) time from injury to diagnosis was significantly longer at Division II/III institutions (1 [0-4] days) compared to Division I Power 5 (0 [0-1] days) and Division I Non-Power 5 (0 [0-1] days) institutions (p < 0.001). Likewise, Division II/III athletes (15 [11-22] days) took significantly longer to return to sport after concussion than Division I Power 5 (10 [7-16] days) and Division I Non-Power 5 (11 [7-18.5] days) athletes (p < 0.001). CONCLUSION: Division II/III athletes had delayed concussion diagnoses and return to sport timelines compared to Division I athletes. Our results suggest that differences in sports medicine resources across NCAA divisions may influence injury recognition and recovery in collegiate athletes with concussion.

Sport Type and Risk of Subsequent Injury in Collegiate Athletes Following Concussion: a LIMBIC MATARS Consortium Investigation.

OBJECTIVE: To investigate the association between sport type (collision, contact, non-contact) and subsequent injury risk following concussion in collegiate athletes. MATERIALS AND METHODS: This retrospective chart review of 248 collegiate athletes with diagnosed concussions (age: 20.0 ± 1.4 years; height: 179.6 ± 10.9 cm; mass: 79.0 ± 13.6 kg, 63% male) from NCAA athletic programs (n = 11) occurred between the 2015-2020 athletic seasons. Acute injuries that occurred within six months following concussion were evaluated. Subsequent injuries were grouped by lower extremity, upper extremity, trunk, or concussion. The independent variable was sport type: collision, contact, non-contact. A Cox proportional hazard model was used to assess the risk of subsequent injury between sport types. RESULTS: Approximately 28% (70/248) of athletes sustained a subsequent acute injury within six months post-concussion. Collision sport athletes had a significantly higher risk of sustaining any injury (HR: 0.41, p < 0.001, 95% CI: 0.28, 0.62), lower extremity (HR: 0.55, p = 0.04, 95% CI: 0.32, 0.97), and upper extremity (HR: 0.41, p = 0.01, 95% CI: 0.20, 0.81) injuries following concussion. No differences between sport types were observed for other injuries. CONCLUSION: Collision sport athletes had a higher rate of any subsequent injury, lower, and upper extremity injuries following concussion. Future research should focus on sport-specific secondary injury prevention efforts.

Physical activity and recovery following concussion in collegiate athletes: a LIMBIC MATARS Consortium Investigation.

OBJECTIVE: To investigate whether routine daily activities (RDA), non-prescribed exercise (Non-ERx), or prescribed exercise (ERx) were associated with recovery from sport-related concussion (SRC) in collegiate athletes. MATERIALS AND METHODS: Data for this cross-sectional, retrospective chart review of collegiate athletes diagnosed with SRC (n = 285[39.6% female], age = 19.5 ± 1.4 years) were collected during the 2015-16 to 2019-20 athletic seasons. The independent variable was group (RDA, Non-ERx, ERx). Dependent variables included days from date of diagnosis to symptom resolution (Dx-SR) and SR to return to sport (SR-RTS). RESULTS: Those in the Non-ERx group took nearly 1.3 times longer to achieve SR (IRR = 1.28, 95% CI: 1.11, 1.46) and, 1.8 times longer for RTS (IRR = 1.82, 95% CI: 1.11, 2.71) when compared to those in the RDA group. No other comparisons were significant. CONCLUSION: Collegiate athletes in the Non-ERx group took approximately 1 week longer to achieve SR as compared to the RDA and ERx groups. Our findings suggest that if exercise is recommended following SRC, it must be clearly and specifically prescribed. If exercise parameters cannot be prescribed, or monitored, RDA appear to be similarly beneficial during recovery for collegiate athletes with concussion.

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

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

The American Congress of Rehabilitation Medicine Diagnostic Criteria for Mild Traumatic Brain Injury.

OBJECTIVE: To develop new diagnostic criteria for mild traumatic brain injury (TBI) that are appropriate for use across the lifespan and in sports, civilian trauma, and military settings. DESIGN: Rapid evidence reviews on 12 clinical questions and Delphi method for expert consensus. PARTICIPANTS: The Mild Traumatic Brain Injury Task Force of the American Congress of Rehabilitation Medicine Brain Injury Special Interest Group convened a Working Group of 17 members and an external interdisciplinary expert panel of 32 clinician-scientists. Public stakeholder feedback was analyzed from 68 individuals and 23 organizations. RESULTS: The first 2 Delphi votes asked the expert panel to rate their agreement with both the diagnostic criteria for mild TBI and the supporting evidence statements. In the first round, 10 of 12 evidence statements reached consensus agreement. Revised evidence statements underwent a second round of expert panel voting, where consensus was achieved for all. For the diagnostic criteria, the final agreement rate, after the third vote, was 90.7%. Public stakeholder feedback was incorporated into the diagnostic criteria revision prior to the third expert panel vote. A terminology question was added to the third round of Delphi voting, where 30 of 32 (93.8%) expert panel members agreed that 'the diagnostic label 'concussion' may be used interchangeably with 'mild TBI' when neuroimaging is normal or not clinically indicated.' CONCLUSIONS: New diagnostic criteria for mild TBI were developed through an evidence review and expert consensus process. Having unified diagnostic criteria for mild TBI can improve the quality and consistency of mild TBI research and clinical care.

Clinical research findings from the long-term impact of military-relevant brain injury consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) 2013-2021.

This is a summary of the published research from the 14 observational, longitudinal and big-data, epidemiological studies supported by the LIMBIC-CENC program from 2013-2021 examining the long-term effects of combat-related traumatic brain injury (TBI). Findings from these 43 primary and secondary analyses include: 1) unique fluid, advanced neuroimaging and electrophysiologic biomarkers associated with mild traumatic brain injury (mTBI), number of mTBIs and related dysfunction, 2) increases in a range of chronic difficulties, including neurosensory, sleep, pain, cognitive deficits, behavioral disorders, overall symptom burden, healthcare costs and service-connected disability, associated with mTBI, all-severity traumatic brain injury (TBI), blast exposure, and number of mTBIs, and 3) increases in the risk for suicide and neurodegeneration, including dementia and Parkinson's disease, associated with mTBI and all-severity TBI. Ongoing LIMBIC-CENC longitudinal and epidemiologic research will clarify, confirm and expand upon these findings.

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.

Demographic, military, and health comorbidity variables by mild TBI and PTSD status in the LIMBIC-CENC cohort.

OBJECTIVE: To describe associations of demographic, military, and health comorbidity variables between mild traumatic brain injury (mTBI) history and posttraumatic stress disorder (PTSD) status in a sample of Former and current military personnel. SETTING: Participants recruited and tested at seven VA sites and one military training facility in the LIMBIC-CENC prospective longitudinal study (PLS), which examines the long-term mental health, neurologic, and cognitive outcomes among previously combat-deployed U.S. Service Members and Veterans (SM/Vs). PARTICIPANTS: A total of 1,540 SM/Vs with a history of combat exposure. Data were collected between 1/1/2015 through 3/31/2019. DESIGN: Cross-sectional analysis using data collected at enrollment into the longitudinal study cohort examining demographic, military, and health comorbidity variables across PTSD and mTBI subgroups. MAIN MEASURES: PTSD Checklist for DSM-5 (PCL-5), mTBI diagnostic status, Patient Health Questionnaire 9-item (PHQ-9), Pittsburgh Sleep Quality Index (PSQI), AUDIT-C, and other self-reported demographic, military, and health comorbidity variables. RESULTS: Ten years following an index date of mTBI exposure or mid-point of military deployment, combat-exposed SM/Vs with both mTBI history and PTSD had the highest rates of depression symptoms, pain, and sleep apnea risk relative to SM/Vs without both of these conditions. SM/Vs with PTSD, irrespective of mTBI history, had high rates of obesity, sleep problems, and pain. CONCLUSION: The long-term symptom reporting and health comorbidities among SM/Vs with mTBI history and PTSD suggest that ongoing monitoring and intervention is critical for addressing symptoms and improving quality of life.

Clinical features of dementia cases ascertained by ICD coding in LIMBIC-CENC multicenter study of mild traumatic brain injury.

OBJECTIVE: Describe dementia cases identified through International Classification of Diseases (ICD) coding in the Long-term Impact of Military-relevant Brain Injury Consortium - Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) multicenter prospective longitudinal study (PLS) of mild traumatic brain injury (mTBI). DESIGN: Descriptive case series using cross-sectional data. METHODS: Veterans Affairs (VA) health system data including ICD codes were obtained for 1563 PLS participants through the VA Informatics and Computing Infrastructure (VINCI). Demographic, injury, and clinical characteristics of Dementia positive and negative cases are described. RESULTS: Five cases of dementia were identified, all under 65 years old. The dementia cases all had a history of blast-related mTBI and all had self-reported functional problems and four had PTSD symptomatology at the clinical disorder range. Cognitive testing revealed some deficits especially in the visual memory and verbal learning and memory domains, and that two of the cases might be false positives. CONCLUSIONS: ICD codes for early dementia in the VA system have specificity concerns, but could be indicative of cognitive performance and self-reported cognitive function. Further research is needed to better determine links to blast exposure, blast-related mTBI, and PTSD to early dementia in the military population.

Advanced brain age in deployment-related traumatic brain injury: A LIMBIC-CENC neuroimaging study.

OBJECTIVE: To determine if history of mild traumatic brain injury (mTBI) is associated with advanced or accelerated brain aging among the United States (US) military Service Members and Veterans. METHODS: Eight hundred and twenty-two participants (mean age = 40.4 years, 714 male/108 female) underwent MRI sessions at eight sites across the US. Two hundred and one participants completed a follow-up scan between five months and four years later. Predicted brain ages were calculated using T1-weighted MRIs and then compared with chronological ages to generate an Age Deviation Score for cross-sectional analyses and an Interval Deviation Score for longitudinal analyses. Participants also completed a neuropsychological battery, including measures of both cognitive functioning and psychological health. RESULT: In cross-sectional analyses, males with a history of deployment-related mTBI showed advanced brain age compared to those without (t(884) = 2.1, p = .038), while this association was not significant in females. In follow-up analyses of the male participants, severity of posttraumatic stress disorder (PTSD), depression symptoms, and alcohol misuse were also associated with advanced brain age. CONCLUSION: History of deployment-related mTBI, severity of PTSD and depression symptoms, and alcohol misuse are associated with advanced brain aging in male US military Service Members and Veterans.

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.

Health symptoms after war zone deployment-related mild traumatic brain injury: contributions of mental disorders and lifetime brain injuries.

PRIMARY OBJECTIVE: To gain a better understanding of the complex relationship between combat deployment-related mild traumatic brain injury (mTBI) and persistent post-concussive symptoms (PPCSs), taking into consideration a wide range of potentially mediating and confounding factors. RESEARCH DESIGN: Cross-sectional. METHODS AND PROCEDURES: Subjects were 613 U. S. military Veterans and Service Members who served during operations Enduring Freedom, Iraqi Freedom, or New Dawn (OEF/OIF/OND) and completed a structured interview of mental disorders and a battery of questionnaires. Hierarchical binary logistic regression analyses were used to test the hypotheses. MAIN OUTCOMES AND RESULTS: After accounting for mental disorders, lifetime mTBIs outside of OEF/OIF/OND deployment, medical conditions, and injury/demographic characteristics, deployment-related mTBI continued to be associated with several PPCSs (headaches, sleep disturbance, and difficulty making decisions). Deployment-related mTBI was also associated with two symptoms not normally associated with mTBI (nausea/upset stomach and numbness/tingling). CONCLUSIONS: After adjusting for a wide range of factors, OEF/OIF/OND deployment-related mTBI was still associated with PPCSs on average 10 years after the injury. These findings suggest that mTBI sustained during OEF/OIF/OND deployment may have enduring negative health effects. More studies are needed that prospectively and longitudinally track health and mental health outcomes after TBI.

Recruiting for a multicentre DoD and VA longitudinal study: lessons learned.

PRIMARY OBJECTIVE: The primary objective of the study is to identify and delineate effective recruitment practises in a large, multi-site, longitudinal, observational study employing both military service members and Veterans. SETTING: Four Chronic Effects of Neurotrauma Consortium sites. DESIGN: A descriptive study. RESULTS: Overall and cohort-specific recruitment increased with the addition of focused recruitment strategies and a military/Veteran-centric recruitment director. CONCLUSION: Use of site-specific strategies aligned with local Institutional Review Board procedures and emphasizing awareness of service member organizational allegiances was the key to effective recruiting. Adding a recruitment director with background similar to study participants coincided with significantly improved overall participant numbers and specific subpopulations of research subjects, thus adding to the value of the study.

Chronic Effects of Neurotrauma Consortium (CENC) multicentre study interim analysis: Differences between participants with positive versus negative mild TBI histories.

OBJECTIVES: Compare characteristics and outcomes of combat-exposed military personnel with positive versus negative mild traumatic brain injury (mTBI) histories. SETTING: Recruitment was from registration lists and ambulatory clinics at four veterans administration hospitals. PARTICIPANTS: Consented veterans and service members completing initial evaluation by September 2016 (n = 492). DESIGN: Observational with cross-sectional analyses. MAIN MEASURES: Multimodal assessments including structured interviews, record review, questionnaires, neuroendocrine labs and neurocognitive and sensorimotor performance. RESULTS: In unadjusted comparisons to those absent lifetime mTBI, the mTBI positive group (84%) had greater combat exposure, more potential concussive events, less social support and more comorbidities, including asthma, sleeping problems and post-traumatic stress disorder. They also fared worse on all sensory and pain symptom scores and self-reported functional and global outcomes. They had poorer scores on Wechsler Adult Intelligence Scale-IV coding (processing speed), TMT-B (visual-motor integration and executive function) and two posturography subtests, but were otherwise equal to TBI negative participants on neurocognitive and sensorimotor testing and neuroendocrine levels. CONCLUSIONS: Although differences in characteristics exist which were not adjusted for, participants with historical mTBI have greater symptomatology and life functioning difficulties compared with non-TBI. Performance measures were less dissimilar between groups. These findings will guide further research within this accruing cohort.

Symptom Trajectories After Military Blast Exposure and the Influence of Mild Traumatic Brain Injury.

BACKGROUND: Blast-related mild traumatic brain injury (blast mTBI) is a signature wound of recent US military conflicts in the Middle East, but the relatedness of postconcussive symptoms (PCS) to the blast mTBI is unclear, and longitudinal symptom data are sparse. OBJECTIVES: To characterize postdeployment symptom levels and trajectories and to determine relationship to blast mTBI. METHODS: A total of 216 participants within 2 years of blast exposure during deployment underwent structured interviews or algorithmic questionnaires for blast mTBI. Detailed symptom inventories for PCS, pain, posttraumatic stress disorder, and depression were taken serially at enrollment, 6 months, and 12 months later. Repeated-measure analysis of variance models were built. RESULTS: Up to 50% of participants had at least 1 high-grade blast mTBI (with posttraumatic amnesia), 31% had low-grade only, and 19% had neither. Within the entire cohort, all 4 composite symptom scores started high and stayed unchanged. Between blast mTBI groups, symptom scores differed at every time point with some evidence of convergence over time. The PCS groups, different by definition to start, diverged further over time with those initially more symptomatic becoming relatively more so. CONCLUSIONS: History of blast mTBI accompanied by posttraumatic amnesia is associated with greater nonspecific symptoms after deployment, and prognosis for improvement when symptoms are prominent is poor.