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Belding JN, Bonkowski J, Englert R. Traumatic brain injury and occupational risk of low-level blast exposure on adverse career outcomes: an examination of administrative and medical separations from Service (2005-2015). Front Neurol 2024; 15:1389757. [PMID: 38689879 PMCID: PMC11058224 DOI: 10.3389/fneur.2024.1389757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/02/2024] [Indexed: 05/02/2024] Open
Abstract
Introduction Although traumatic brain injury (TBI) has been linked with adverse long-term health, less research has examined whether TBI is linked with non-clinical outcomes including involuntary job loss. Symptoms associated with TBI may influence one's ability to maintain gainful employment including employment in the U.S. military. That influence may impact military service members with exposure to repetitive low-level blast (LLB). Understanding the association between TBI and involuntary job loss outcomes among military populations is particularly important as it may be associated with differences in eligibility for post-service benefits. The purpose of the present research was to determine whether (1) TBI and related conditions are associated with involuntary job loss (i.e., medical and administrative separations from service) among military personnel, and (2) occupational risk of LLB is associated with involuntary job loss in both the presence and absence of clinical diagnoses of TBI and related conditions. Method This research leveraged population-level data from the Career History Archival Medical and Personnel System for enlisted personnel who served on active duty between 2005-2015. Risk of LLB exposure was categorized using military occupational specialty as a proxy. Medical diagnoses were identified using ICD-9 codes. Separations for medical and administrative reasons were identified. Results Risk for administrative separation differed across medical diagnoses of interest, but those who worked in high-risk occupations were more likely to be administratively separated than those working in low-risk occupations. Risk for medical separation was associated with occupational risk of LLB and each of the diagnoses of interest, though significant interactions suggested that the effects of certain diagnoses of interest (e.g., concussion, cognitive problems, postconcussive syndrome, migraines) on medical separations was greater among those working in high-risk occupations. Discussion Taken together, the present research suggests that TBI and associated medical conditions, as well as occupational risk of LLB, are associated with long-term involuntary job loss for medical reasons. This study is the first to demonstrate involuntary military job loss outcomes associated with TBI, mental health conditions, and conditions associated with blast exposure using both inpatient and outpatient population-level data and may have important implications for civilian employment and post-service benefits.
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Affiliation(s)
| | - James Bonkowski
- Naval Health Research Center, San Diego, CA, United States
- Leidos, Inc., San Diego, CA, United States
| | - Robyn Englert
- Naval Health Research Center, San Diego, CA, United States
- Leidos, Inc., San Diego, CA, United States
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Lange RT, French LM, Lippa SM, Gillow KC, Bailie JM, Turner SM, Hungerford LD, Brickell TA. Convergent and Discriminant Validity of the Blast Exposure Threshold Survey in United States Military Service Members and Veterans. J Neurotrauma 2024; 41:934-941. [PMID: 38032755 PMCID: PMC11005380 DOI: 10.1089/neu.2023.0379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
Abstract
The Blast Exposure Threshold Survey (BETS) is a recently developed and promising new self-report measure of lifetime blast exposure (LBE). However, there are no studies that have examined the psychometric properties of the BETS, which currently limits its clinical utility. The purpose of this study was to examine the convergent and discriminant validity of the BETS by comparing the BETS Generalized Blast Exposure Value (GBEV) to six variables hypothesized to be associated with LBE (i.e., single-item LBE, combat exposure, years in the military, number of combat deployments, and military occupation specialty [MOS]) and three variables hypothesized not to be associated with LBE (i.e., age at the time of injury, estimated pre-morbid Full-Scale Intelligence Quotient [FSIQ], and resilience). Participants were 202 United States service members and veterans prospectively enrolled from three military medical treatment facilities (68.7%) and via community recruitment initiatives (31.3%). Participants completed the BETS, Combat Exposure Scale (CES), Deployment Risk and Resiliency Inventory-2 Combat Experiences (DRRI-2 CE), Traumatic Brain Injury-Quality of Life Resilience scale, and a brief structured interview. For some analyses, participants were classified into two blast risk MOS groups: high (n = 89) and low (n = 94). The BETS GBEV was not significantly correlated with all three non-blast related variables (rs = 0.01 to rs = -0.12). In contrast, GBEV was significantly (p < 0.001) associated with all blast-related variables; single-item LBE (rs = 0.76), CES (rs = 0.58), number of combat deployments (rs = 0.53), DRRI-2 CE (rs = 0.48), and high blast risk MOS (r = 0.36, medium effect size). However, a stronger relationship was found between the blast-related variables and three modified GBEV scores when excluding some small weapons categories; single-item LBE (rs = 0.80-0.82), CES (rs = 0.64-0.67), number of combat deployments (rs = 0.56), DRRI-2 CE (rs = 0.51-0.53), and high blast risk MOS (r = 0.42-0.49, medium-large effect size). This is the first study to examine the psychometric properties of the BETS. Overall, these results offer support for the convergent and discriminant validity of the BETS. In order to ensure that the BETS can be confidently used as a valid and reliable measure of LBE, more research is needed to further examine the psychometric properties of the test, particularly with regard to the establishment of test-retest reliability.
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Affiliation(s)
- Rael T. Lange
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Louis M. French
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Sara M. Lippa
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Kelly C. Gillow
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, CICONIX, Annapolis, Maryland, USA
| | - Jason M. Bailie
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- 33 Area Branch Clinic Camp, Pendleton, California, USA
| | - Stephanie M. Turner
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
| | - Lars D. Hungerford
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- Naval Medical Center, San Diego, California, USA
| | - Tracey A. Brickell
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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Liu Q, Wang Z, Sun S, Nemes J, Brenner LA, Hoisington A, Skotak M, LaValle CR, Ge Y, Carr W, Haghighi F. Association of Blast Exposure in Military Breaching with Intestinal Permeability Blood Biomarkers Associated with Leaky Gut. Int J Mol Sci 2024; 25:3549. [PMID: 38542520 PMCID: PMC10971443 DOI: 10.3390/ijms25063549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/13/2024] [Accepted: 03/18/2024] [Indexed: 04/14/2024] Open
Abstract
Injuries and subclinical effects from exposure to blasts are of significant concern in military operational settings, including tactical training, and are associated with self-reported concussion-like symptomology and physiological changes such as increased intestinal permeability (IP), which was investigated in this study. Time-series gene expression and IP biomarker data were generated from "breachers" exposed to controlled, low-level explosive blast during training. Samples from 30 male participants at pre-, post-, and follow-up blast exposure the next day were assayed via RNA-seq and ELISA. A battery of symptom data was also collected at each of these time points that acutely showed elevated symptom reporting related to headache, concentration, dizziness, and taking longer to think, dissipating ~16 h following blast exposure. Evidence for bacterial translocation into circulation following blast exposure was detected by significant stepwise increase in microbial diversity (measured via alpha-diversity p = 0.049). Alterations in levels of IP protein biomarkers (i.e., Zonulin, LBP, Claudin-3, I-FABP) assessed in a subset of these participants (n = 23) further evidenced blast exposure associates with IP. The observed symptom profile was consistent with mild traumatic brain injury and was further associated with changes in bacterial translocation and intestinal permeability, suggesting that IP may be linked to a decrease in cognitive functioning. These preliminary findings show for the first time within real-world military operational settings that exposures to blast can contribute to IP.
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Affiliation(s)
- Qingkun Liu
- James J. Peters VA Medical Center, Bronx, NY 10468, USA; (Q.L.); (Z.W.); (S.S.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Zhaoyu Wang
- James J. Peters VA Medical Center, Bronx, NY 10468, USA; (Q.L.); (Z.W.); (S.S.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Shengnan Sun
- James J. Peters VA Medical Center, Bronx, NY 10468, USA; (Q.L.); (Z.W.); (S.S.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Jeffrey Nemes
- Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA (C.R.L.); (W.C.)
| | - Lisa A. Brenner
- Rocky Mountain Mental Illness, Research, Education and Clinical Care, Department of Veterans Affairs, Aurora, CO 80045, USA; (L.A.B.); (A.H.)
- Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
| | - Andrew Hoisington
- Rocky Mountain Mental Illness, Research, Education and Clinical Care, Department of Veterans Affairs, Aurora, CO 80045, USA; (L.A.B.); (A.H.)
- Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
- Department of Systems Engineering and Management, Air Force Institute of Technology, Wright-Patterson Air Force Base, OH 45433, USA
| | - Maciej Skotak
- Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA (C.R.L.); (W.C.)
| | - Christina R. LaValle
- Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA (C.R.L.); (W.C.)
| | - Yongchao Ge
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
| | - Walter Carr
- Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA (C.R.L.); (W.C.)
| | - Fatemeh Haghighi
- James J. Peters VA Medical Center, Bronx, NY 10468, USA; (Q.L.); (Z.W.); (S.S.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA;
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Lippa SM, Bailie JM, French LM, Brickell TA, Lange RT. Lifetime blast exposure is not related to cognitive performance or psychiatric symptoms in US military personnel. Clin Neuropsychol 2024:1-23. [PMID: 38494345 DOI: 10.1080/13854046.2024.2328881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 03/05/2024] [Indexed: 03/19/2024]
Abstract
Objective: The present study aimed to examine the impact of lifetime blast exposure (LBE) on neuropsychological functioning in service members and veterans (SMVs). Method: Participants were 282 SMVs, with and without history of traumatic brain injury (TBI), who were prospectively enrolled in a Defense and Veterans Brain Injury Center (DVBIC)-Traumatic Brain Injury Center of Excellence (TBICoE) Longitudinal TBI Study. A cross-sectional analysis of baseline data was conducted. LBE was based on two factors: Military Occupational Speciality (MOS) and SMV self-report. Participants were divided into three groups based on LBE: Blast Naive (n = 61), Blast + Low Risk MOS (n = 96), Blast + High Risk MOS (n = 125). Multivariate analysis of variance (MANOVA) was used to examine group differences on neurocognitive domains and the Minnesota Multiphasic Personality Inventory-2 Restructured Form. Results: There were no statistically significant differences in attention/working memory, processing speed, executive functioning, and memory (Fs < 1.75, ps > .1, ηp2s < .032) or in General Cognition (Fs < 0.95, ps > .3, ηp2s < .008). Prior to correction for covariates, lifetime blast exposure was related to Restructured Clinical (F(18,542) = 1.77, p = .026, ηp2 = .055), Somatic/Cognitive (F(10,550) = 1.99, p = .033, ηp2 = .035), and Externalizing Scales (F(8,552) = 2.17, p = .028, ηp2 = .030); however, these relationships did not remain significant after correction for covariates (Fs < 1.53, ps > .145, ηp2s < .032). Conclusions: We did not find evidence of a relationship between LBE and neurocognitive performance or psychiatric symptoms. This stands in contrast to prior studies demonstrating an association between lifetime blast exposure and highly sensitive blood biomarkers and/or neuroimaging. Overall, findings suggest the neuropsychological impact of lifetime blast exposure is minimal in individuals remaining in or recently retired from military service.
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Affiliation(s)
- Sara M Lippa
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Jason M Bailie
- Traumatic Brain Injury Center of Excellence, Bethesda, MD, USA
- Naval Hospital Camp Pendleton, Oceanside, CA, USA
- General Dynamics Information Technology, Fairfax, VA, USA
| | - Louis M French
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Traumatic Brain Injury Center of Excellence, Bethesda, MD, USA
| | - Tracey A Brickell
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Traumatic Brain Injury Center of Excellence, Bethesda, MD, USA
- General Dynamics Information Technology, Fairfax, VA, USA
| | - Rael T Lange
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD, USA
- Traumatic Brain Injury Center of Excellence, Bethesda, MD, USA
- General Dynamics Information Technology, Fairfax, VA, USA
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
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Sachdeva T, Ganpule SG. Twenty Years of Blast-Induced Neurotrauma: Current State of Knowledge. Neurotrauma Rep 2024; 5:243-253. [PMID: 38515548 PMCID: PMC10956535 DOI: 10.1089/neur.2024.0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024] Open
Abstract
Blast-induced neurotrauma (BINT) is an important injury paradigm of neurotrauma research. This short communication summarizes the current knowledge of BINT. We divide the BINT research into several broad categories-blast wave generation in laboratory, biomechanics, pathology, behavioral outcomes, repetitive blast in animal models, and clinical and neuroimaging investigations in humans. Publications from 2000 to 2023 in each subdomain were considered. The analysis of the literature has brought out salient aspects. Primary blast waves can be simulated reasonably in a laboratory using carefully designed shock tubes. Various biomechanics-based theories of BINT have been proposed; each of these theories may contribute to BINT by generating a unique biomechanical signature. The injury thresholds for BINT are in the nascent stages. Thresholds for rodents are reasonably established, but such thresholds (guided by primary blast data) are unavailable in humans. Single blast exposure animal studies suggest dose-dependent neuronal pathologies predominantly initiated by blood-brain barrier permeability and oxidative stress. The pathologies were typically reversible, with dose-dependent recovery times. Behavioral changes in animals include anxiety, auditory and recognition memory deficits, and fear conditioning. The repetitive blast exposure manifests similar pathologies in animals, however, at lower blast overpressures. White matter irregularities and cortical volume and thickness alterations have been observed in neuroimaging investigations of military personnel exposed to blast. Behavioral changes in human cohorts include sleep disorders, poor motor skills, cognitive dysfunction, depression, and anxiety. Overall, this article provides a concise synopsis of current understanding, consensus, controversies, and potential future directions.
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Affiliation(s)
- Tarun Sachdeva
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, India
| | - Shailesh G. Ganpule
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, India
- Department of Design, Indian Institute of Technology Roorkee, Roorkee, India
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6
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Lange RT, French LM, Lippa SM, Gillow K, Tippett CE, Barnhart EA, Glazer ME, Bailie JM, Hungerford L, Brickell TA. High Lifetime Blast Exposure Using the Blast Exposure Threshold Survey Is Associated With Worse Warfighter Brain Health Following Mild Traumatic Brain Injury. J Neurotrauma 2024; 41:186-198. [PMID: 37650835 DOI: 10.1089/neu.2023.0133] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
Abstract
The purpose of this study was to extend previous research by examining the relationship between lifetime blast exposure and neurobehavioral functioning after mild TBI (MTBI) by (a) using a comprehensive measure of lifetime blast exposure, and (b) controlling for the influence of post-traumatic stress disorder (PTSD). Participants were 103 United States service members and veterans (SMVs) with a medically documented diagnosis of MTBI, recruited from three military treatment facilities (74.8%) and community-based recruitment initiatives (25.2%, e.g., social media, flyers). Participants completed a battery of neurobehavioral measures 12 or more months post-injury (Neurobehavioral Symptom Inventory, PTSD-Checklist PCLC, TBI-Quality of Life), including the Blast Exposure Threshold Survey (BETS). The sample was classified into two lifetime blast exposure (LBE) groups: High (n = 57) and Low (n = 46) LBE. In addition, the sample was classified into four LBE/PTSD subgroups: High PTSD/High LBE (n = 38); High PTSD/Low LBE (n = 19); Low PTSD/High LBE (n = 19); and Low PTSD/Low LBE (n = 27). The High LBE group had consistently worse scores on all neurobehavioral measures compared with the Low LBE group. When controlling for the influence of PTSD (using ANCOVA), however, only a handful of group differences remained. When comparing measures across the four LBE/PTSD subgroups, in the absence of clinically meaningful PTSD symptoms (i.e., Low PTSD), participants with High LBE had worse scores on the majority of neurobehavioral measures (e.g., post-concussion symptoms, sleep, fatigue). When examining the total number of clinically elevated measures, the High LBE subgroup consistently had a greater number of clinically elevated scores compared with the Low LBE subgroup for the majority of comparisons (i.e., four to 15 or more elevated symptoms). In contrast, in the presence of clinically meaningful PTSD symptoms (i.e., High PTSD), there were no differences between High versus Low LBE subgroups for all measures. When examining the total number of clinically elevated measures, however, there were meaningful differences between High versus Low LBE subgroups for those comparisons that included a high number of clinically elevated scores (i.e., six to 10 or more), but not for a low number of clinically elevated scores (i.e., one to five or more). High LBE, as quantified using a more comprehensive measure than utilized in past research (i.e., BETS), was associated with worse overall neurobehavioral functioning after MTBI. This study extends existing literature showing that lifetime blast exposure, that is largely subconcussive, may negatively impact warfighter brain health and readiness beyond diagnosable brain injury.
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Affiliation(s)
- Rael T Lange
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- University of British Columbia, Vancouver, British Columbia, Canada
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Louis M French
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Sara M Lippa
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Kelly Gillow
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, CICONIX, Annapolis, Maryland, USA
| | - Corie E Tippett
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, CICONIX, Annapolis, Maryland, USA
| | - Elizabeth A Barnhart
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- Contractor, Henry Jackson Foundation, Bethesda, Maryland, USA
- Center for Neuroscience and Regenerative Medicine, Bethesda, Maryland, USA
| | - Megan E Glazer
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, Henry Jackson Foundation, Bethesda, Maryland, USA
| | - Jason M Bailie
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- 33 Area Branch Clinic Camp Pendleton, California, USA
| | - Lars Hungerford
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- Naval Medical Center, San Diego, California, USA
| | - Tracey A Brickell
- Traumatic Brain Injury Center of Excellence, Silver Spring, Maryland, USA
- Walter Reed National Military Medical Center, Bethesda, Maryland, USA
- National Intrepid Center of Excellence, Bethesda, Maryland, USA
- Contractor, General Dynamics Information Technology, Silver Spring, Maryland, USA
- Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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Martindale SL, Belding JN, Crawford CD, Rowland JA. Validation of Military Occupational Specialty as a Proxy for Blast Exposure Using the Salisbury Blast Interview. J Neurotrauma 2023; 40:2321-2329. [PMID: 37058360 DOI: 10.1089/neu.2023.0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023] Open
Abstract
Abstract Evaluating large data sets precludes the ability to directly measure individual experiences, instead relying on proxies to infer certain constructs. Blast exposure is a construct of study currently in its infancy, resulting in diverse definitions and measurements across studies. The purpose of the present study was to validate military occupational specialty (MOS) as a proxy for blast exposure in combat veterans. A total of 256 veterans (86.33% male) completed the Salisbury Blast Interview (SBI) and Mid-Atlantic Mental Illness Research Education and Clinical Center (MIRECC) Assessment of Traumatic Brain Injury (MMA-TBI). MOS was collected through record review and categorized into low and high risk for blast exposure. Chi-square analyses and t tests compared SBI metrics between MOS categories. Receiver operating characteristic (ROC) analyses evaluated the diagnostic accuracy of MOS category in determining blast exposure severity. Veterans in high-risk MOS were more likely to have experienced blast and deployment TBI (ps < 0.001) than were those in low-risk MOS. ROC analyses indicated good specificity (81.29-88.00) for blast and deployment TBI outcomes, suggesting that low-risk MOS is generally associated with an absence of blast and deployment TBI outcomes. Sensitivity was low (36.46-51.14), indicating that MOS risk level was not a good predictor of the presence of these outcomes. Results demonstrate that high-risk MOSs will identify individuals with blast exposure and deployment TBI history whereas low-risk MOSs will capture a highly variable group. Accuracy of MOS categorization was not acceptable for diagnostic-level tests; however, results support its use as a screening measure for a history of exposure to blast, use in epidemiological studies, and considerations for military policy.
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Affiliation(s)
- Sarah L Martindale
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research and Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, North Carolina, USA
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | | | - Cameron D Crawford
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research and Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, North Carolina, USA
| | - Jared A Rowland
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research and Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, North Carolina, USA
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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8
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Saar-Ashkenazy R, Naparstek S, Dizitzer Y, Zimhoni N, Friedman A, Shelef I, Cohen H, Shalev H, Oxman L, Novack V, Ifergane G. Neuro-psychiatric symptoms in directly and indirectly blast exposed civilian survivors of urban missile attacks. BMC Psychiatry 2023; 23:423. [PMID: 37312064 DOI: 10.1186/s12888-023-04943-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/07/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Blast-explosion may cause traumatic brain injury (TBI), leading to post-concussion syndrome (PCS). In studies on military personnel, PCS symptoms are highly similar to those occurring in post-traumatic stress disorder (PTSD), questioning the overlap between these syndromes. In the current study we assessed PCS and PTSD in civilians following exposure to rocket attacks. We hypothesized that PCS symptomatology and brain connectivity will be associated with the objective physical exposure, while PTSD symptomatology will be associated with the subjective mental experience. METHODS Two hundred eighty nine residents of explosion sites have participated in the current study. Participants completed self-report of PCS and PTSD. The association between objective and subjective factors of blast and clinical outcomes was assessed using multivariate analysis. White-matter (WM) alterations and cognitive abilities were assessed in a sub-group of participants (n = 46) and non-exposed controls (n = 16). Non-parametric analysis was used to compare connectivity and cognition between the groups. RESULTS Blast-exposed individuals reported higher PTSD and PCS symptomatology. Among exposed individuals, those who were directly exposed to blast, reported higher levels of subjective feeling of danger and presented WM hypoconnectivity. Cognitive abilities did not differ between groups. Several risk factors for the development of PCS and PTSD were identified. CONCLUSIONS Civilians exposed to blast present higher PCS/PTSD symptomatology as well as WM hypoconnectivity. Although symptoms are sub-clinical, they might lead to the future development of a full-blown syndrome and should be considered carefully. The similarities between PCS and PTSD suggest that despite the different etiology, namely, the physical trauma in PCS and the emotional trauma in PTSD, these are not distinct syndromes, but rather represent a combined biopsychological disorder with a wide spectrum of behavioral, emotional, cognitive and neurological symptoms.
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Affiliation(s)
- R Saar-Ashkenazy
- Faculty of Social-Work, Ashkelon Academic College, 12 Ben Tzvi St, PO Box 9071, 78211, Ashkelon, Israel.
- Department of Cognitive-Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | - S Naparstek
- Department of Psychology Ben-Gurion, University of the Negev, Beer-Sheva, Israel
- Department of Psychology, Bar-Ilan University, Ramat Gan, Israel
| | - Y Dizitzer
- Clinical Research Center, Soroka University Medical Center, Beer-Sheva, Israel
| | - N Zimhoni
- Clinical Research Center, Soroka University Medical Center, Beer-Sheva, Israel
| | - A Friedman
- Department of Cognitive-Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, B3H4R2, Canada
| | - I Shelef
- Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Department of Diagnostic Imaging, Soroka University Medical Center, Beer-Sheva, Israel
| | - H Cohen
- Anxiety and Stress Research Unit, Faculty of Health Sciences, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - H Shalev
- Department of Psychiatry, Soroka University Medical Center, Beer-Sheva, Israel
| | - L Oxman
- Clinical Research Center, Soroka University Medical Center, Beer-Sheva, Israel
| | - V Novack
- Clinical Research Center, Soroka University Medical Center, Beer-Sheva, Israel
| | - G Ifergane
- Department of Neurology, Soroka University Medical Center, Beer-Sheva, Israel
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9
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Englert RM, Belding JN, Thomsen CJ. Self-Reported Symptoms in U.S. Marines Following Blast- and Impact-Related Concussion. Mil Med 2023; 188:usad026. [PMID: 36794787 DOI: 10.1093/milmed/usad026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/30/2022] [Accepted: 01/23/2023] [Indexed: 02/17/2023] Open
Abstract
INTRODUCTION Recent research on traumatic brain injury (TBI) has suggested that the mechanism of injury (i.e., whether the TBI was caused by high-level blast [HLB] vs. direct physical impact to the head) may be an important factor in injury severity, symptomology, and recovery because of differences in physiological effects of each type of injury on the brain. However, differences in self-reported symptomology resulting from HLB- vs. impact-related TBIs have not been thoroughly examined. This study tested the hypothesis that HLB- and impact-related concussions result in different self-reported symptoms in an enlisted Marine Corps population. MATERIALS AND METHODS All records of 2008 and 2012 Post-Deployment Health Assessment (PDHA) forms completed by enlisted active duty Marines between January 2008 and January 2017 were examined for self-reported concussion, mechanism of injury, and self-reported symptoms experienced during deployment. Concussion events were categorized as either blast- or impact-related; individual symptoms were categorized as neurological, musculoskeletal, or immunological. A series of logistic regressions were performed to examine associations between self-reported symptoms experienced by healthy controls and Marines who endorsed (1) any concussion (mTBI), (2) a probable blast-related concussion (mbTBI), and (3) a probable impact-related concussion (miTBI); analyses were also stratified by PTSD. To determine if there were significant differences between odds ratios (ORs) for mbTBIs vs. miTBIs, 95% CIs were examined for overlap. RESULTS Marines with a probable concussion, regardless of the mechanism of injury, were significantly more likely to report all symptoms (OR range: 1.7-19.3). Overall, mbTBIs, compared with miTBIs, resulted in higher odds of symptom reporting for eight symptoms on the 2008 PDHA (tinnitus, trouble hearing, headache, memory problems, dizziness, dim vision, trouble concentrating, and vomiting) and six symptoms on the 2012 PDHA (tinnitus, trouble hearing, headaches, memory problems, balance problems, and increased irritability), all of which were in the neurological symptom category. Conversely, odds of symptom reporting were higher for Marines experiencing miTBIs (vs. mbTBIs) for seven symptoms on the 2008 PDHA (skin diseases or rashes, chest pain, trouble breathing, persistent cough, red eyes, fever, and other) and one symptom on the 2012 PDHA (skin rash and/or lesion), all of which were in the immunological symptoms category. mbTBI (vs. miTBI) was consistently associated with greater odds of reporting tinnitus, trouble hearing, and memory problems, regardless of PTSD status. CONCLUSIONS These findings support recent research suggesting that the mechanism of injury may play an important role in symptom reporting and/or physiological changes to the brain after concussion. The results of this epidemiological investigation should be used to guide further research on the physiological effects of concussion, diagnostic criteria for neurological injuries, and treatment modalities for various concussion-related symptoms.
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Affiliation(s)
- Robyn Martin Englert
- Leidos, Military and Vetrans Health Solutions, Reston, VA 20190, USA
- Naval Health Research Center, Health and Behavioral Sciences Department, San Diego, CA 92106, USA
| | - Jennifer N Belding
- Leidos, Military and Vetrans Health Solutions, Reston, VA 20190, USA
- Naval Health Research Center, Health and Behavioral Sciences Department, San Diego, CA 92106, USA
| | - Cynthia J Thomsen
- Naval Health Research Center, Health and Behavioral Sciences Department, San Diego, CA 92106, USA
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10
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Walker WC, O'Neil ME, Ou Z, Pogoda TK, Belanger HG, Scheibel RS, Presson AP, Miles SR, Wilde EA, Tate DF, Troyanskaya M, Pugh MJ, Jak A, Cifu DX. Can mild traumatic brain injury alter cognition chronically? A LIMBIC-CENC multicenter study. Neuropsychology 2023; 37:1-19. [PMID: 36174184 PMCID: PMC10117581 DOI: 10.1037/neu0000855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE While outcome from mild traumatic brain injury (mTBI) is generally favorable, concern remains over potential negative long-term effects, including impaired cognition. This study examined the link between cognitive performance and remote mTBIs within the Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) multicenter, observational study of Veterans and service members (SMs) with combat exposure. METHOD Baseline data of the participants passing all cognitive performance validity tests (n = 1,310) were used to conduct a cross-sectional analysis. Using multivariable regression models that adjusted for covariates, including age and estimated preexposure intellectual function, positive mTBI history groups, 1-2 lifetime mTBIs (nonrepetitive, n = 614), and 3 + lifetime mTBIs (repetitive; n = 440) were compared to TBI negative controls (n = 256) on each of the seven cognitive domains computed by averaging Z scores of prespecified component tests. Significance levels were adjusted for multiple comparisons. RESULTS Neither of the mTBI positive groups differed from the mTBI negative control group on any of the cognitive domains in multivariable analyses. Findings were also consistently negative across sensitivity analyses (e.g., mTBIs as a continuous variable, number of blast-related mTBIs, or years since the first and last mTBI). CONCLUSIONS Our findings demonstrate that the average veteran or SM who experienced one or more mTBIs does not have postacute objective cognitive deficits due to mTBIs alone. A holistic health care approach including comorbidity assessment is indicated for patients reporting chronic cognitive difficulties after mTBI(s), and strategies for addressing misattribution may be beneficial. Future study is recommended with longitudinal designs to assess within-subjects decline from potential neurodegeneration. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Affiliation(s)
| | | | | | - Terri K Pogoda
- Center for Healthcare Organization and Implementation Research
| | | | | | | | | | | | - David F Tate
- Department of Physical Medicine and Rehabilitation
| | | | - Mary Jo Pugh
- George E. Wahlen Veterans Affairs Salt Lake City Healthcare System
| | - Amy Jak
- VA San Diego Healthcare System
| | - David X Cifu
- Department of Physical Medicine and Rehabilitation
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11
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Belding JN, Kolaja CA, Rull RP, Trone DW. Single and repeated high-level blast, low-level blast, and new-onset self-reported health conditions in the U.S. Millennium Cohort Study: An exploratory investigation. Front Neurol 2023; 14:1110717. [PMID: 37025202 PMCID: PMC10070873 DOI: 10.3389/fneur.2023.1110717] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/13/2023] [Indexed: 04/08/2023] Open
Abstract
Introduction Although previous research suggests that overpressure exposure from either high-level blast (HLB) or low-level blast (LLB) are harmful to health, to date no large-scale studies with representative samples of military personnel have utilized prospective designs and self-reported measures to examine the relationships between blast exposure and health conditions. To address these limitations, this analysis of data from the Millennium Cohort Study (MCS), the largest and longest running study of U.S. service members and veterans, examined (1) whether single or repeated HLB exposure is associated with self-reported diagnoses of illness and injury, (2) whether repeated HLB is associated with greater risk than single HLB, (3) potential adverse consequences of LLB exposure using military occupation as a proxy, and (4) the combined effects of single or repeated HLB and LLB exposure. Method MCS participants who completed the 2011-2013 survey (N = 138,949) were classified as having been exposed to "no," "single," or "repeated" HLB exposure, and into low or high risk of exposure to LLB based on occupation. Participants self-reported diagnosis of 45 medical conditions; newly reported diagnoses were regressed on single and repeated (vs. no) HLB, occupational risk of LLB, and relevant interactions using logistic regression. Results Single and repeated HLB were associated with new onset of 25 and 29 diagnoses, respectively; repeated HLB exposure was associated with greater risk than single HLB exposure for five diagnoses (e.g., PTSD, depression). Occupational risk of LLB was associated with 11 diagnoses (e.g., PTSD, significant hearing loss). Additionally, 14 significant interactions were detected across 11 diagnoses. Discussion Findings suggest that overpressure exposure (including single HLB, repeated HLB, and occupational risk of LLB) may increase the risks of self-reporting clinical diagnoses of PTSD, hearing loss, chronic fatigue syndrome, neuropathy-caused reduced sensation in the hands and feet, depression, vision loss, sinusitis, reflux, and anemia. Furthermore, the combination of HLB and LLB exposure may be associated with greater risk of migraines, PTSD, and impaired fecundity. These findings provide further evidence of the potential adverse consequences associated with overpressure exposure and underscore the necessity of public health surveillance initiatives for blast exposure and/or safety recommendations for training and operational environments.
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Affiliation(s)
- Jennifer N. Belding
- Leidos, San Diego, CA, United States
- Deployment Health Research Department, Naval Health Research Center, San Diego, CA, United States
- *Correspondence: Jennifer N. Belding
| | - Claire A. Kolaja
- Leidos, San Diego, CA, United States
- Deployment Health Research Department, Naval Health Research Center, San Diego, CA, United States
| | - Rudolph P. Rull
- Deployment Health Research Department, Naval Health Research Center, San Diego, CA, United States
| | - Daniel W. Trone
- Deployment Health Research Department, Naval Health Research Center, San Diego, CA, United States
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12
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Edlow BL, Bodien YG, Baxter T, Belanger H, Cali R, Deary K, Fischl B, Foulkes AS, Gilmore N, Greve DN, Hooker JM, Huang SY, Kelemen JN, Kimberly WT, Maffei C, Masood M, Perl D, Polimeni JR, Rosen BR, Tromly S, Tseng CEJ, Yao EF, Zurcher NR, Mac Donald CL, Dams-O'Connor K. Long-Term Effects of Repeated Blast Exposure in United States Special Operations Forces Personnel: A Pilot Study Protocol. J Neurotrauma 2022; 39:1391-1407. [PMID: 35620901 PMCID: PMC9529318 DOI: 10.1089/neu.2022.0030] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Emerging evidence suggests that repeated blast exposure (RBE) is associated with brain injury in military personnel. United States (U.S.) Special Operations Forces (SOF) personnel experience high rates of blast exposure during training and combat, but the effects of low-level RBE on brain structure and function in SOF have not been comprehensively characterized. Further, the pathophysiological link between RBE-related brain injuries and cognitive, behavioral, and physical symptoms has not been fully elucidated. We present a protocol for an observational pilot study, Long-Term Effects of Repeated Blast Exposure in U.S. SOF Personnel (ReBlast). In this exploratory study, 30 active-duty SOF personnel with RBE will participate in a comprehensive evaluation of: 1) brain network structure and function using Connectome magnetic resonance imaging (MRI) and 7 Tesla MRI; 2) neuroinflammation and tau deposition using positron emission tomography; 3) blood proteomics and metabolomics; 4) behavioral and physical symptoms using self-report measures; and 5) cognition using a battery of conventional and digitized assessments designed to detect subtle deficits in otherwise high-performing individuals. We will identify clinical, neuroimaging, and blood-based phenotypes that are associated with level of RBE, as measured by the Generalized Blast Exposure Value. Candidate biomarkers of RBE-related brain injury will inform the design of a subsequent study that will test a diagnostic assessment battery for detecting RBE-related brain injury. Ultimately, we anticipate that the ReBlast study will facilitate the development of interventions to optimize the brain health, quality of life, and battle readiness of U.S. SOF personnel.
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Affiliation(s)
- Brian L Edlow
- Harvard Medical School, 1811, 175 Cambridge Street - Suite 300, Boston, Massachusetts, United States, 02115.,Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Yelena G Bodien
- Massachusetts General Hospital, 2348, Department of Neurology, 101 Merrimac, Boston, Massachusetts, United States, 02114;
| | - Timothy Baxter
- University of South Florida, 7831, Institute for Applied Engineering, Tampa, Florida, United States;
| | - Heather Belanger
- University of South Florida, 7831, Department of Psychiatry and Behavioral Neurosciences, Tampa, Florida, United States;
| | - Ryan Cali
- Massachusetts General Hospital, 2348, Boston, Massachusetts, United States;
| | - Katryna Deary
- Navy SEAL Foundation, Virginia Beach, Virginia, United States;
| | - Bruce Fischl
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Room 2301, 149 13th Street, Charlestown, Massachusetts, United States, 02129-2020.,Massachusetts General Hospital;
| | - Andrea S Foulkes
- Massachusetts General Hospital, 2348, Boston, Massachusetts, United States;
| | - Natalie Gilmore
- Massachusetts General Hospital, 2348, Boston, Massachusetts, United States;
| | - Douglas N Greve
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Jacob M Hooker
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Susie Y Huang
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Jessica N Kelemen
- Massachusetts General Hospital, 2348, Boston, Massachusetts, United States;
| | - W Taylor Kimberly
- Massachusetts General Hospital, 2348, Boston, Massachusetts, United States;
| | - Chiara Maffei
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Maryam Masood
- Massachusetts General Hospital, 2348, Boston, Massachusetts, United States;
| | - Daniel Perl
- Uniformed Services University of the Health Sciences, 1685, Pathology, 4301 Jones Bridge Road, Room B3138, Bethesda, Maryland, United States, 20814;
| | - Jonathan R Polimeni
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Bruce R Rosen
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Charlestown, Massachusetts, United States;
| | - Samantha Tromly
- University of South Florida, 7831, Institute for Applied Engineering, Tampa, Florida, United States;
| | - Chieh-En J Tseng
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Eveline F Yao
- United States Special Operations Command, Office of the Surgeon General, MacDill Air Force Base, United States;
| | - Nicole R Zurcher
- Massachusetts General Hospital, 2348, Athinoula A. Martinos Center for Biomedical Imaging, Boston, Massachusetts, United States;
| | - Christine L Mac Donald
- University of Washington, 7284, Department of Neurological Surgery, Seattle, Washington, United States;
| | - Kristen Dams-O'Connor
- Icahn School of Medicine at Mount Sinai, 5925, Rehabilitation Medicine, One Gustave Levy Place, Box 1163, New York, New York, United States, 10029; kristen.dams-o'
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13
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Miller MR, DiBattista A, Patel MA, Daley M, Tenn C, Nakashima A, Rhind SG, Vartanian O, Shiu MY, Caddy N, Garrett M, Saunders D, Smith I, Jetly R, Fraser DD. A Distinct Metabolite Signature in Military Personnel Exposed to Repetitive Low-Level Blasts. Front Neurol 2022; 13:831792. [PMID: 35463119 PMCID: PMC9021419 DOI: 10.3389/fneur.2022.831792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/10/2022] [Indexed: 11/30/2022] Open
Abstract
Military Breachers and Range Staff (MBRS) are subjected to repeated sub-concussive blasts, and they often report symptoms that are consistent with a mild traumatic brain injury (mTBI). Biomarkers of blast injury would potentially aid blast injury diagnosis, surveillance and avoidance. Our objective was to identify plasma metabolite biomarkers in military personnel that were exposed to repeated low-level or sub-concussive blast overpressure. A total of 37 military members were enrolled (18 MBRS and 19 controls), with MBRS having participated in 8–20 breaching courses per year, with a maximum exposure of 6 blasts per day. The two cohorts were similar except that the number of blast exposures were significantly higher in the MBRS, and the MBRS cohort suffered significantly more post-concussive symptoms and poorer health on assessment. Metabolomics profiling demonstrated significant differences between groups with 74% MBRS classification accuracy (CA). Feature reduction identified 6 metabolites that resulted in a MBRS CA of 98%, and included acetic acid (23.7%), formate (22.6%), creatine (14.8%), acetone (14.2%), methanol (12,7%), and glutamic acid (12.0%). All 6 metabolites were examined with individual receiver operating characteristic (ROC) curve analyses and demonstrated areas-under-the-curve (AUCs) of 0.82–0.91 (P ≤ 0.001) for MBRS status. Several parsimonious combinations of three metabolites increased accuracy of ROC curve analyses to AUCs of 1.00 (P < 0.001), while a combination of volatile organic compounds (VOCs; acetic acid, acetone and methanol) yielded an AUC of 0.98 (P < 0.001). Candidate biomarkers for chronic blast exposure were identified, and if validated in a larger cohort, may aid surveillance and care of military personnel. Future point-of-care screening could be developed that measures VOCs from breath, with definitive diagnoses confirmed with plasma metabolomics profiling.
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Affiliation(s)
- Michael R. Miller
- Lawson Health Research Institute, London, ON, Canada
- Department of Pediatrics, Western University, London, ON, Canada
| | - Alicia DiBattista
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Neurolytix Inc., Toronto, ON, Canada
| | - Maitray A. Patel
- Department of Computer Science, Western University, London, ON, Canada
| | - Mark Daley
- Department of Computer Science, Western University, London, ON, Canada
- The Vector Institute for Artificial Intelligence, Toronto, ON, Canada
| | - Catherine Tenn
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Ann Nakashima
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
| | - Shawn G. Rhind
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, ON, Canada
| | - Oshin Vartanian
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Maria Y. Shiu
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
| | - Norleen Caddy
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Michelle Garrett
- Defence Research and Development Canada, Suffield Research Centre, Medicine Hat, AB, Canada
| | - Doug Saunders
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
| | - Ingrid Smith
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
| | - Rakesh Jetly
- Canadian Forces Health Services, National Defence Headquarters, Ottawa, ON, Canada
- Department of Psychiatry, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Psychiatry, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Douglas D. Fraser
- Lawson Health Research Institute, London, ON, Canada
- Department of Pediatrics, Western University, London, ON, Canada
- Neurolytix Inc., Toronto, ON, Canada
- Clinical Neurological Sciences, Western University, London, ON, Canada
- Physiology and Pharmacology, Western University, London, ON, Canada
- *Correspondence: Douglas D. Fraser
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14
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Chen S, Siedhoff HR, Zhang H, Liu P, Balderrama A, Li R, Johnson C, Greenlief CM, Koopmans B, Hoffman T, DePalma RG, Li DP, Cui J, Gu Z. Low-intensity blast induces acute glutamatergic hyperexcitability in mouse hippocampus leading to long-term learning deficits and altered expression of proteins involved in synaptic plasticity and serine protease inhibitors. Neurobiol Dis 2022; 165:105634. [PMID: 35077822 DOI: 10.1016/j.nbd.2022.105634] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 11/26/2022] Open
Abstract
Neurocognitive consequences of blast-induced traumatic brain injury (bTBI) pose significant concerns for military service members and veterans with the majority of "invisible injury." However, the underlying mechanism of such mild bTBI by low-intensity blast (LIB) exposure for long-term cognitive and mental deficits remains elusive. Our previous studies have shown that mice exposed to LIB result in nanoscale ultrastructural abnormalities in the absence of gross or apparent cellular damage in the brain. Here we tested the hypothesis that glutamatergic hyperexcitability may contribute to long-term learning deficits. Using brain slice electrophysiological recordings, we found an increase in averaged frequencies with a burst pattern of miniature excitatory postsynaptic currents (mEPSCs) in hippocampal CA3 neurons in LIB-exposed mice at 1- and 7-days post injury, which was blocked by a specific NMDA receptor antagonist AP5. In addition, cognitive function assessed at 3-months post LIB exposure by automated home-cage monitoring showed deficits in dynamic patterns of discrimination learning and cognitive flexibility in LIB-exposed mice. Collected hippocampal tissue was further processed for quantitative global-proteomic analysis. Advanced data-independent acquisition for quantitative tandem mass spectrometry analysis identified altered expression of proteins involved in synaptic plasticity and serine protease inhibitors in LIB-exposed mice. Some were correlated with the ability of discrimination learning and cognitive flexibility. These findings show that acute glutamatergic hyperexcitability in the hippocampus induced by LIB may contribute to long-term cognitive dysfunction and protein alterations. Studies using this military-relevant mouse model of mild bTBI provide valuable insights into developing a potential therapeutic strategy to ameliorate hyperexcitability-modulated LIB injuries.
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Affiliation(s)
- Shanyan Chen
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Heather R Siedhoff
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Hua Zhang
- Department of Medicine, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Pei Liu
- Charles W. Gehrke Proteomics Center, University of Missouri, Columbia, MO 65211, USA
| | - Ashley Balderrama
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Runting Li
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Catherine Johnson
- Department of Mining and Nuclear Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA
| | - C Michael Greenlief
- Charles W. Gehrke Proteomics Center, University of Missouri, Columbia, MO 65211, USA
| | | | - Timothy Hoffman
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Medicine, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Ralph G DePalma
- Office of Research and Development, Department of Veterans Affairs, Washington DC 20420, USA; Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - De-Pei Li
- Department of Medicine, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Jiankun Cui
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA.
| | - Zezong Gu
- Truman VA Hospital Research Service, Columbia, MO 65201, USA; Department of Pathology & Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO 65212, USA.
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15
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Siedhoff HR, Chen S, Song H, Cui J, Cernak I, Cifu DX, DePalma RG, Gu Z. Perspectives on Primary Blast Injury of the Brain: Translational Insights Into Non-inertial Low-Intensity Blast Injury. Front Neurol 2022; 12:818169. [PMID: 35095749 PMCID: PMC8794583 DOI: 10.3389/fneur.2021.818169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/20/2021] [Indexed: 12/18/2022] Open
Abstract
Most traumatic brain injuries (TBIs) during military deployment or training are clinically "mild" and frequently caused by non-impact blast exposures. Experimental models were developed to reproduce the biological consequences of high-intensity blasts causing moderate to severe brain injuries. However, the pathophysiological mechanisms of low-intensity blast (LIB)-induced neurological deficits have been understudied. This review provides perspectives on primary blast-induced mild TBI models and discusses translational aspects of LIB exposures as defined by standardized physical parameters including overpressure, impulse, and shock wave velocity. Our mouse LIB-exposure model, which reproduces deployment-related scenarios of open-field blast (OFB), caused neurobehavioral changes, including reduced exploratory activities, elevated anxiety-like levels, impaired nesting behavior, and compromised spatial reference learning and memory. These functional impairments associate with subcellular and ultrastructural neuropathological changes, such as myelinated axonal damage, synaptic alterations, and mitochondrial abnormalities occurring in the absence of gross- or cellular damage. Biochemically, we observed dysfunctional mitochondrial pathways that led to elevated oxidative stress, impaired fission-fusion dynamics, diminished mitophagy, decreased oxidative phosphorylation, and compensated cell respiration-relevant enzyme activity. LIB also induced increased levels of total tau, phosphorylated tau, and amyloid β peptide, suggesting initiation of signaling cascades leading to neurodegeneration. We also compare translational aspects of OFB findings to alternative blast injury models. By scoping relevant recent research findings, we provide recommendations for future preclinical studies to better reflect military-operational and clinical realities. Overall, better alignment of preclinical models with clinical observations and experience related to military injuries will facilitate development of more precise diagnosis, clinical evaluation, treatment, and rehabilitation.
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Affiliation(s)
- Heather R. Siedhoff
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, MO, United States
| | - Shanyan Chen
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, MO, United States
| | - Hailong Song
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, MO, United States
| | - Jiankun Cui
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, MO, United States
| | - Ibolja Cernak
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, GA, United States
| | - David X. Cifu
- Department of Physical Medicine and Rehabilitation, Virginia Commonwealth University School of Medicine, Richmond, VA, United States
| | - Ralph G. DePalma
- Office of Research and Development, Department of Veterans Affairs, Washington, DC, United States
- Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Zezong Gu
- Department of Pathology and Anatomical Sciences, University of Missouri School of Medicine, Columbia, MO, United States
- Harry S. Truman Memorial Veterans' Hospital Research Service, Columbia, MO, United States
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16
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Occupational Risk of Low-Level Blast Exposure and TBI-Related Medical Diagnoses: A Population-Based Epidemiological Investigation (2005-2015). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182412925. [PMID: 34948535 PMCID: PMC8700773 DOI: 10.3390/ijerph182412925] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/17/2022]
Abstract
Because traumatic brain injury (TBI)—most often caused by exposure to high-level blast (HLB)—is a leading cause of medical evacuations of deployed U.S. service members in recent conflicts, researchers seek to identify risk factors for TBI. Previous research using self-reported data has identified low-level blast (LLB) as one such risk factor and suggests an association with susceptibility to and symptoms associated with TBI. This article presents a population-based study of all branches of military service that examines the association between occupational risk for LLB and both clinically diagnosed TBIs—from concussions to severe and penetrating TBIs—and conditions commonly comorbid with concussion. Using archival medical and career records from >2 million service members between 2005–2015, this work demonstrates that occupational risk of LLB is associated with any TBI, mild TBI, moderate TBI, cognitive problems, communication problems, hearing problems, headaches, any behavioral health condition, anxiety, drug abuse/dependence, alcohol abuse/dependence, delirium/dementia, posttraumatic stress disorder, post-concussive syndrome, tinnitus, fatigue, and migraines. Understanding the full scope of the effects of LLB on service members will help ensure the health and readiness of service members and may influence both military policy and clinical practice guidelines for blast-induced injuries.
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Martindale SL, Ord AS, Rule LG, Rowland JA. Effects of blast exposure on psychiatric and health symptoms in combat veterans. J Psychiatr Res 2021; 143:189-195. [PMID: 34500348 DOI: 10.1016/j.jpsychires.2021.09.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/25/2021] [Accepted: 09/01/2021] [Indexed: 11/28/2022]
Abstract
Blast exposure is common among service members, but the chronic psychiatric effects associated with blast exposure are not well-characterized independent of a resulting mild traumatic brain injury (TBI). This analysis evaluated whether blast exposure severity was independently associated with or exacerbated symptom report beyond posttraumatic stress disorder (PTSD) and mild TBI. Participants were Iraq and Afghanistan combat veterans (N = 275; 86.55% male), 71.27% with history of blast exposure, 29.82% current diagnosis of PTSD, and 45.45% with mild TBI. All participants completed diagnostic interviews for PTSD, lifetime TBI, and lifetime blast exposure. Self-reported psychiatric and health outcomes included posttraumatic stress symptoms, depressive symptoms, neurobehavioral symptoms, sleep quality, pain interference, and quality of life. Blast severity was associated with PTSD (B = 2.00), depressive (B = 0.76), and neurobehavioral (B = 1.69) symptoms beyond PTSD diagnosis and mild TBI history. Further, blast severity accounted entirely (i.e., indirect/mediation effect) for the association between TBI and posttraumatic stress (B = 1.62), depressive (B = 0.61), and neurobehavioral (B = 1.38) symptoms. No interaction effects were present. Exposure to blast is an independent factor influencing psychiatric symptoms in veterans beyond PTSD and mild TBI. Results highlight that blast exposure severity may be a more relevant risk factor than deployment mild TBI in combat veterans and should be considered in the etiology of psychiatric symptom presentation and complaints. Further, severity of psychological distress due to the combat environment may be an explanatory mechanism by which blast exposure mediates the relationship between mild TBI and symptom outcomes.
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Affiliation(s)
- Sarah L Martindale
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research & Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, NC, USA; Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Anna S Ord
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research & Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, NC, USA; Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Lakeysha G Rule
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research & Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, NC, USA
| | - Jared A Rowland
- Mid-Atlantic Mental Illness Research, Education, and Clinical Center (MA-MIRECC), Research & Academic Affairs Service Line, W. G. (Bill) Hefner VA Healthcare System, Salisbury, NC, USA; Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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Belding JN, Egnoto M, Englert RM, Fitzmaurice S, Thomsen CJ. Getting on the Same Page: Consolidating Terminology to Facilitate Cross-Disciplinary Health-Related Blast Research. Front Neurol 2021; 12:695496. [PMID: 34248831 PMCID: PMC8264539 DOI: 10.3389/fneur.2021.695496] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
The consequences of blast exposure (including both high-level and low-level blast) have been a focal point of military interest and research for years. Recent mandates from Congress (e.g., National Defense Authorization Act for Fiscal Year 2018, section 734) have further accelerated these efforts, facilitating collaborations between research teams from a variety of disciplinary backgrounds. Based on findings from a recent scoping review, we argue that the scientific field of blast research is plagued by inconsistencies in both conceptualization of relevant constructs and terminology used to describe them. These issues hamper our ability to interpret study methods and findings, hinder efforts to integrate findings across studies to reach scientific consensus, and increase the likelihood of redundant efforts. We argue that multidisciplinary experts in this field require a universal language and clear, standardized terminology to further advance the important work of examining the effects of blast exposure on human health, performance, and well-being. To this end, we present a summary of descriptive conventions regarding the language scientists currently use when discussing blast-related exposures and outcomes based on findings from a recent scoping review. We then provide prescriptive conventions about how these terms should be used by clearly conceptualizing and explicitly defining relevant constructs. Specifically, we summarize essential concepts relevant to the study of blast, precisely distinguish between high-level blast and low-level blast, and discuss how the terms acute, chronic, exposure, and outcome should be used when referring to the health-related consequences of blast exposure.
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Affiliation(s)
- Jennifer N Belding
- Leidos, San Diego, CA, United States.,Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, United States
| | - Michael Egnoto
- Study of Terrorism and Responses to Terrorism, University of Maryland, College Park, MD, United States
| | - Robyn M Englert
- Leidos, San Diego, CA, United States.,Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, United States
| | - Shannon Fitzmaurice
- Leidos, San Diego, CA, United States.,Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, United States
| | - Cynthia J Thomsen
- Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, United States
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