The Experts below are selected from a list of 2133 Experts worldwide ranked by ideXlab platform
Gary H. Kamimori - One of the best experts on this subject based on the ideXlab platform.
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Sensor orientation and other factors which increase the Blast Overpressure reporting errors.
PloS one, 2020Co-Authors: Anthony Misistia, Maciej Skotak, Arturo Cardenas, Eren Alay, Namas Chandra, Gary H. KamimoriAbstract:This study compared the response of the wearable sensors tested against the industry-standard pressure transducers at Blast Overpressure (BOP) levels typically experienced in training. We systematically evaluated the effects of the sensor orientation with respect to the direction of the incident shock wave and demonstrated how the averaging methods affect the reported pressure values. The evaluated methods included averaging peak Overpressure and impulse of all four sensors mounted on a helmet, taking the average of the three sensors, or isolating the incident pressure equivalent using two sensors. The experimental procedures were conducted in controlled laboratory conditions using the shock tube, and some of the findings were verified in field conditions with live fire charges during explosive breaching training. We used four different orientations (0°, 90°, 180°, and 270°) of the headform retrofitted with commonly fielded helmets (ACH, ECH, Ops-Core) with four B3 Blast Gauge sensors. We determined that averaging the peak Overpressure values overestimates the actual dosage experienced by operators, which is caused by the reflected pressure contribution. This conclusion is valid despite the identified limitation of the B3 gauges that consistently underreport the peak reflected Overpressure, compared to the industry-standard sensors. We also noted consistent overestimation of the impulse. These findings demonstrate that extreme caution should be exercised when interpreting occupational Blast exposure results without knowing the orientation of the sensors. Pure numerical values without the geometrical, training-regime specific information such as the position of the sensors, the distance and orientation of the trainee to the source of the Blast wave, and weapon system used will inevitably lead to erroneous estimation of the individual and cumulative Blast Overpressure (BOP) dosages. Considering that the 4 psi (~28 kPa) incident BOP is currently accepted as the threshold exposure safety value, a misinterpretation of exposure level may lead to an inaccurate estimation of BOP at the minimum standoff distance (MSD), or exclusion criteria.
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Neurocognitive Performance Deficits Related to Immediate and Acute Blast Overpressure Exposure
Frontiers in neurology, 2019Co-Authors: Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Alejandro N. Ramos, Michael J. Egnoto, Walter Carr, Gary H. KamimoriAbstract:Addressing the concerns surrounding Blast injury for the military community is a pressing matter. Specifically, sub-concussive Blast effects, or those Blast effects which do not yield a medical diagnosis but can result in symptom reporting and negative self-reported outcomes, are becoming increasingly important. This work evaluates explosive Blast Overpressure and impulse effects at the sub-concussive level on neurocognitive performance assessed with the Defense Automated Neurobehavioral Assessment (DANA) across seven breacher training courses conducted by the US Military. The results reported here come from 202 healthy, male military volunteer participants. Findings indicate that the neurocognitive task appearing most sensitive to identifying performance change is the DANA Procedural Reaction Time (PRT) subtask which may involve a sufficient level of challenge to reliably detect a small, transient cognitive impairment among a healthy undiagnosed population. The Blast characteristic that was consistently associated with performance change was peak Overpressure. Overall, this study provides evidence that increasing Blast Overpressure, defined as peak Overpressure experienced in a training day, can lead to transient degradations in neurocognitive performance as seen on the DANA PRT subtask, which may generalize to other capabilities.
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The Role of Very Low Level Blast Overpressure in Symptomatology.
Frontiers in neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (
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the role of very low level Blast Overpressure in symptomatology
Frontiers in Neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (<3psi) associated with these exposures has largely been ignored. Notably, the current vLLB or acoustic literature has focused exclusively on auditory defects, and has not addressed the broader concerns of Soldier health and readiness. This work was prompted by reports of symptomatology such as headache, nausea, slowed reaction time, and balance/hearing complications among personnel undergoing frequent exposures to low Overpressure accompanied by high acoustic pressures. To more fully address the consequences associated with low Overpressure exposures (<3psi), a pilot proof-of-concept study was implemented, and data was acquired at two sites on the Fort Benning grenade course range. Findings indicated Overpressures ranged from 0.14-0.42 psi (0.97 – 2.89 kPa) at range 1 and 0.22 – 0.30 psi (1.52 – 2.07 kPa) on range 2 of the grenade course. Corresponding sound-meter data varied from 153.72 - 163.22 dBP. Headache and long think were the most frequently reported symptoms (3/6 instructors), with lightheadedness, ringing of the ears, restlessness, frustration, and irritability also increasing in 2/6 of the instructors post exposure. Long think (prolonged thinking), ringing of the ears, restlessness, and irritability were the most severe symptoms, with the highest reported post exposure value rating a 3 on the 0-4-point scale. We demonstrate that low-level repeated Overpressure exposure can result in transient symptomatology that overlaps with sub-concussive like effects.
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Brain-related proteins as serum biomarkers of acute, subconcussive Blast Overpressure exposure: A cohort study of military personnel.
PloS one, 2019Co-Authors: Angela M. Boutté, Christina R. Lavalle, Bharani Thangavelu, Jeffrey Nemes, Janice S. Gilsdorf, Deborah A. Shear, Gary H. KamimoriAbstract:Repeated exposure to Blast Overpressure remains a major cause of adverse health for military personnel who, as a consequence, are at a higher risk for neurodegenerative disease and suicide. Acute, early tracking of Blast related effects holds the promise of rapid health assessment prior to onset of chronic problems. Current techniques used to determine Blast-related effects rely upon reporting of symptomology similar to that of concussion and neurocognitive assessment relevant to operational decrement. Here, we describe the results of a cross sectional study with pared observations. The concentration of multiple TBI-related proteins was tested in serum collected within one hour of Blast exposure as a quantitative and minimally invasive strategy to augment assessment of Blast-exposure effects that are associated with concussion-like symptomology and reaction time decrements. We determined that median simple reaction time (SRT) was slowed in accordance with serum Nf-L, tau, Aβ-40, and Aβ-42 elevation after Overpressure exposure. In contrast, median levels of serum GFAP decreased. Individual, inter-subject analysis revealed positive correlations between changes in Nf-L and GFAP, and in Aβ-40 compared to Aβ-42. The change in Nf-L was negatively associated with tau, Aβ-40, and Aβ-42. Participants reported experiencing headaches, dizziness and taking longer to think. Dizziness was associated with reaction time decrements, GFAP or NfL suppression, as well as Aβ peptide elevation. UCH-L1 elevation had a weak association with mTBI/concussion history. Multiplexed serum biomarker quantitation, coupled with reaction time assessment and symptomology determined before and after Blast exposure, may serve as a platform for tracking adverse effects in the absence of a head wound or diagnosed concussion. We propose further evaluation of serum biomarkers, which are often associated with TBI, in the context of acute operational Blast exposures.
Joseph B Long - One of the best experts on this subject based on the ideXlab platform.
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Pulmonary injury risk curves and behavioral changes from Blast Overpressure exposures of varying frequency and intensity in rats.
Scientific reports, 2020Co-Authors: Venkata Siva Sai Sujith Sajja, Jonathan K. Statz, Stephen T Ahlers, Donna Wilder, Irene D. Gist, Peter B. Walker, Joseph B LongAbstract:At present, there are no set guidelines establishing cumulative limits for Blast exposure numbers and intensities in military personnel, in combat or training operations. The objective of the current study was to define lung injury, pathology, and associated behavioral changes from primary repeated Blast lung injury under appropriate exposure conditions and combinations (i.e. Blast Overpressure (BOP) intensity and exposure frequency) using an advanced Blast simulator. Male Sprague Dawley rats were exposed to BOP frontally and laterally at a pressure range of ~ 8.5-19 psi, for up to 30 daily exposures. The extent of lung injury was identified at 24 h following BOP by assessing the extent of surface hemorrhage/contusion, Hematoxylin and Eosin staining, and behavioral deficits with open field activity. Lung injury was mathematically modeled to define the military standard 1% lung injury threshold. Significant levels of histiocytosis and inflammation were observed in pressures ≥ 10 psi and orientation effects were observed at pressures ≥ 13 psi. Experimental data demonstrated ~ 8.5 psi is the threshold for hemorrhage/contusion, up to 30 exposures. Modeling the data predicted injury risk up to 50 exposures with intensity thresholds at 8 psi for front exposure and 6psi for side exposures, which needs to be validated further.
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The Role of Very Low Level Blast Overpressure in Symptomatology.
Frontiers in neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (
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the role of very low level Blast Overpressure in symptomatology
Frontiers in Neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (<3psi) associated with these exposures has largely been ignored. Notably, the current vLLB or acoustic literature has focused exclusively on auditory defects, and has not addressed the broader concerns of Soldier health and readiness. This work was prompted by reports of symptomatology such as headache, nausea, slowed reaction time, and balance/hearing complications among personnel undergoing frequent exposures to low Overpressure accompanied by high acoustic pressures. To more fully address the consequences associated with low Overpressure exposures (<3psi), a pilot proof-of-concept study was implemented, and data was acquired at two sites on the Fort Benning grenade course range. Findings indicated Overpressures ranged from 0.14-0.42 psi (0.97 – 2.89 kPa) at range 1 and 0.22 – 0.30 psi (1.52 – 2.07 kPa) on range 2 of the grenade course. Corresponding sound-meter data varied from 153.72 - 163.22 dBP. Headache and long think were the most frequently reported symptoms (3/6 instructors), with lightheadedness, ringing of the ears, restlessness, frustration, and irritability also increasing in 2/6 of the instructors post exposure. Long think (prolonged thinking), ringing of the ears, restlessness, and irritability were the most severe symptoms, with the highest reported post exposure value rating a 3 on the 0-4-point scale. We demonstrate that low-level repeated Overpressure exposure can result in transient symptomatology that overlaps with sub-concussive like effects.
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Repeated Low-Level Blast Overpressure Leads to Endovascular Disruption and Alterations in TDP-43 and Piezo2 in a Rat Model of Blast TBI.
Frontiers in neurology, 2019Co-Authors: Lanier Heyburn, Joseph B Long, Rania Abutarboush, Samantha Y. Goodrich, Jonathan K. Statz, Stephen T Ahlers, Donna Wilder, Rodrigo Urioste, Andrew Batuure, Venkata Siva Sai Sujith SajjaAbstract:Recent evidence linking repeated low-level Blast Overpressure exposure in operational and training environments with neurocognitive decline, neuroinflammation, and neurodegenerative processes has prompted concern over the cumulative deleterious effects of repeated Blast exposure on the brains of service members. Repetitive exposure to low-level primary Blast may cause symptoms (subclinical) similar to those seen in mild traumatic brain injury (TBI), with progressive vascular and cellular changes, which could contribute to neurodegeneration. At the cellular level, the mechanical force associated with Blast exposure can cause cellular perturbations in the brain, leading to secondary injury. To examine the cumulative effects of repetitive Blast on the brain, an advanced Blast simulator (ABS) was used to closely mimic "free-field" Blast. Rats were exposed to 1-4 daily Blasts (one Blast per day, separated by 24 h) at 13, 16, or 19 psi peak incident pressures with a positive duration of 4-5 ms, either in a transverse or longitudinal orientation. Blood-brain barrier (BBB) markers (vascular endothelial growth factor (VEGF), occludin, and claudin-5), transactive response DNA binding protein (TDP-43), and the mechanosensitive channel Piezo2 were measured following Blast exposure. Changes in expression of VEGF, occludin, and claudin-5 after repeated Blast exposure indicate alterations in the BBB, which has been shown to be disrupted following TBI. TDP-43 is very tightly regulated in the brain and altered expression of TDP-43 is found in clinically-diagnosed TBI patients. TDP-43 levels were differentially affected by the number and magnitude of Blast exposures, decreasing after 2 exposures, but increasing following a greater number of exposures at various intensities. Lastly, Piezo2 has been shown to be dysregulated following Blast exposure and was here observed to increase after multiple Blasts of moderate magnitude, indicating that Blast may cause a change in sensitivity to mechanical stimuli in the brain and may contribute to cellular injury. These findings reveal that cumulative effects of repeated exposures to Blast can lead to pathophysiological changes in the brain, demonstrating a possible link between Blast injury and neurodegenerative disease, which is an important first step in understanding how to prevent these diseases in soldiers exposed to Blast.
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Cerebrospinal Fluid Chemokine (C-C Motif) Ligand 2 Is an Early-Response Biomarker for Blast-Overpressure-Wave-Induced Neurotrauma in Rats.
Journal of neurotrauma, 2016Co-Authors: Ying Wang, Donna Wilder, Yanling Wei, Samuel Oguntayo, Lawrence Tong, Irene D. Gist, Peethambaran Arun, Joseph B LongAbstract:Abstract Chemokines and their receptors are of great interest within the milieu of immune responses elicited in the central nervous system in response to trauma. Chemokine (C-C motif)) ligand 2 (CCL2), which is also known as monocyte chemotactic protein-1, has been implicated in the pathogenesis of traumatic brain injury (TBI), brain ischemia, Alzheimer's disease, and other neurodegenerative diseases. In this study, we investigated the time course of CCL2 accumulation in cerebrospinal fluid (CSF) after exposures to single and repeated Blast Overpressures of varied intensities along with the neuropathological changes and motor deficits resulting from these Blast conditions. Significantly increased concentrations of CCL2 in CSF were evident by 1 h of Blast exposure and persisted over 24 h with peak levels measured at 6 h post-injury. The increased levels of CCL2 in CSF corresponded with both the number and intensities of Blast Overpressure and were also commensurate with the extent of neuromotor impairment ...
Venkata Siva Sai Sujith Sajja - One of the best experts on this subject based on the ideXlab platform.
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Pulmonary injury risk curves and behavioral changes from Blast Overpressure exposures of varying frequency and intensity in rats.
Scientific reports, 2020Co-Authors: Venkata Siva Sai Sujith Sajja, Jonathan K. Statz, Stephen T Ahlers, Donna Wilder, Irene D. Gist, Peter B. Walker, Joseph B LongAbstract:At present, there are no set guidelines establishing cumulative limits for Blast exposure numbers and intensities in military personnel, in combat or training operations. The objective of the current study was to define lung injury, pathology, and associated behavioral changes from primary repeated Blast lung injury under appropriate exposure conditions and combinations (i.e. Blast Overpressure (BOP) intensity and exposure frequency) using an advanced Blast simulator. Male Sprague Dawley rats were exposed to BOP frontally and laterally at a pressure range of ~ 8.5-19 psi, for up to 30 daily exposures. The extent of lung injury was identified at 24 h following BOP by assessing the extent of surface hemorrhage/contusion, Hematoxylin and Eosin staining, and behavioral deficits with open field activity. Lung injury was mathematically modeled to define the military standard 1% lung injury threshold. Significant levels of histiocytosis and inflammation were observed in pressures ≥ 10 psi and orientation effects were observed at pressures ≥ 13 psi. Experimental data demonstrated ~ 8.5 psi is the threshold for hemorrhage/contusion, up to 30 exposures. Modeling the data predicted injury risk up to 50 exposures with intensity thresholds at 8 psi for front exposure and 6psi for side exposures, which needs to be validated further.
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Evaluation of Blast Overpressure Exposure Effects on Concentration of Antibiotics in Mice.
Military medicine, 2020Co-Authors: Vlado Antonic, Venkata Siva Sai Sujith Sajja, Jason Sousa, Ken Nguyen, Yonas A. Alamneh, Brittany I Garry, Maria Medina-rojas, Donna Wilder, Chau Vuong, Brittney PotterAbstract:OBJECTIVE Infection as sequelae to explosion-related injury is an enduring threat to our troops. There are limited data on the effects of Blast on antibiotic pharmacokinetics (PK), pharmacodynamics (PD), and efficacy. The observational study presented here is our Institute's first attempt to address this issue by combining our existing interdepartmental Blast, infection modeling, and in vivo PK/PD capabilities and was designed to determine the PK effects of Blast on the first-line antibiotic, cefazolin, in an in vivo mouse model. METHODS A total of 160 male BALB/c mice were divided to sham and Blast (exposed to Blast Overpressure of 19 psi) in two biological replicates. At 1 hour after Blast/sham exposure, the animals received IV injection of cefazolin (328 mg/kg). Animals were euthanized at 3 minutes, 10 minutes, 15 minutes, 30 minutes, 1 hour, 3 hours, 6 hours, or 10 hours after the injection. Plasma and liver were analyzed for concentration of cefazolin using mass-spectrometry. RESULTS We observed increases in the concentration of cefazolin in the plasma and liver of Blast exposed animals at later time points and increase in elimination half-life. CONCLUSION Our results indicate that Blast-induced physiologic changes significantly influence cefazolin PK and suggest that efficacy could be affected in the context of the Blast; assessment of efficacy and PD effects require further investigation. Metabolic changes resulting from Blast may influence other classes of antibiotics and other therapeutics used with these injuries. Therefore, this may have important treatment considerations in other areas of military medicine.
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The Role of Very Low Level Blast Overpressure in Symptomatology.
Frontiers in neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (
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the role of very low level Blast Overpressure in symptomatology
Frontiers in Neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (<3psi) associated with these exposures has largely been ignored. Notably, the current vLLB or acoustic literature has focused exclusively on auditory defects, and has not addressed the broader concerns of Soldier health and readiness. This work was prompted by reports of symptomatology such as headache, nausea, slowed reaction time, and balance/hearing complications among personnel undergoing frequent exposures to low Overpressure accompanied by high acoustic pressures. To more fully address the consequences associated with low Overpressure exposures (<3psi), a pilot proof-of-concept study was implemented, and data was acquired at two sites on the Fort Benning grenade course range. Findings indicated Overpressures ranged from 0.14-0.42 psi (0.97 – 2.89 kPa) at range 1 and 0.22 – 0.30 psi (1.52 – 2.07 kPa) on range 2 of the grenade course. Corresponding sound-meter data varied from 153.72 - 163.22 dBP. Headache and long think were the most frequently reported symptoms (3/6 instructors), with lightheadedness, ringing of the ears, restlessness, frustration, and irritability also increasing in 2/6 of the instructors post exposure. Long think (prolonged thinking), ringing of the ears, restlessness, and irritability were the most severe symptoms, with the highest reported post exposure value rating a 3 on the 0-4-point scale. We demonstrate that low-level repeated Overpressure exposure can result in transient symptomatology that overlaps with sub-concussive like effects.
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Repeated Low-Level Blast Overpressure Leads to Endovascular Disruption and Alterations in TDP-43 and Piezo2 in a Rat Model of Blast TBI.
Frontiers in neurology, 2019Co-Authors: Lanier Heyburn, Joseph B Long, Rania Abutarboush, Samantha Y. Goodrich, Jonathan K. Statz, Stephen T Ahlers, Donna Wilder, Rodrigo Urioste, Andrew Batuure, Venkata Siva Sai Sujith SajjaAbstract:Recent evidence linking repeated low-level Blast Overpressure exposure in operational and training environments with neurocognitive decline, neuroinflammation, and neurodegenerative processes has prompted concern over the cumulative deleterious effects of repeated Blast exposure on the brains of service members. Repetitive exposure to low-level primary Blast may cause symptoms (subclinical) similar to those seen in mild traumatic brain injury (TBI), with progressive vascular and cellular changes, which could contribute to neurodegeneration. At the cellular level, the mechanical force associated with Blast exposure can cause cellular perturbations in the brain, leading to secondary injury. To examine the cumulative effects of repetitive Blast on the brain, an advanced Blast simulator (ABS) was used to closely mimic "free-field" Blast. Rats were exposed to 1-4 daily Blasts (one Blast per day, separated by 24 h) at 13, 16, or 19 psi peak incident pressures with a positive duration of 4-5 ms, either in a transverse or longitudinal orientation. Blood-brain barrier (BBB) markers (vascular endothelial growth factor (VEGF), occludin, and claudin-5), transactive response DNA binding protein (TDP-43), and the mechanosensitive channel Piezo2 were measured following Blast exposure. Changes in expression of VEGF, occludin, and claudin-5 after repeated Blast exposure indicate alterations in the BBB, which has been shown to be disrupted following TBI. TDP-43 is very tightly regulated in the brain and altered expression of TDP-43 is found in clinically-diagnosed TBI patients. TDP-43 levels were differentially affected by the number and magnitude of Blast exposures, decreasing after 2 exposures, but increasing following a greater number of exposures at various intensities. Lastly, Piezo2 has been shown to be dysregulated following Blast exposure and was here observed to increase after multiple Blasts of moderate magnitude, indicating that Blast may cause a change in sensitivity to mechanical stimuli in the brain and may contribute to cellular injury. These findings reveal that cumulative effects of repeated exposures to Blast can lead to pathophysiological changes in the brain, demonstrating a possible link between Blast injury and neurodegenerative disease, which is an important first step in understanding how to prevent these diseases in soldiers exposed to Blast.
Anthony Misistia - One of the best experts on this subject based on the ideXlab platform.
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Sensor orientation and other factors which increase the Blast Overpressure reporting errors.
PloS one, 2020Co-Authors: Anthony Misistia, Maciej Skotak, Arturo Cardenas, Eren Alay, Namas Chandra, Gary H. KamimoriAbstract:This study compared the response of the wearable sensors tested against the industry-standard pressure transducers at Blast Overpressure (BOP) levels typically experienced in training. We systematically evaluated the effects of the sensor orientation with respect to the direction of the incident shock wave and demonstrated how the averaging methods affect the reported pressure values. The evaluated methods included averaging peak Overpressure and impulse of all four sensors mounted on a helmet, taking the average of the three sensors, or isolating the incident pressure equivalent using two sensors. The experimental procedures were conducted in controlled laboratory conditions using the shock tube, and some of the findings were verified in field conditions with live fire charges during explosive breaching training. We used four different orientations (0°, 90°, 180°, and 270°) of the headform retrofitted with commonly fielded helmets (ACH, ECH, Ops-Core) with four B3 Blast Gauge sensors. We determined that averaging the peak Overpressure values overestimates the actual dosage experienced by operators, which is caused by the reflected pressure contribution. This conclusion is valid despite the identified limitation of the B3 gauges that consistently underreport the peak reflected Overpressure, compared to the industry-standard sensors. We also noted consistent overestimation of the impulse. These findings demonstrate that extreme caution should be exercised when interpreting occupational Blast exposure results without knowing the orientation of the sensors. Pure numerical values without the geometrical, training-regime specific information such as the position of the sensors, the distance and orientation of the trainee to the source of the Blast wave, and weapon system used will inevitably lead to erroneous estimation of the individual and cumulative Blast Overpressure (BOP) dosages. Considering that the 4 psi (~28 kPa) incident BOP is currently accepted as the threshold exposure safety value, a misinterpretation of exposure level may lead to an inaccurate estimation of BOP at the minimum standoff distance (MSD), or exclusion criteria.
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Neurocognitive Performance Deficits Related to Immediate and Acute Blast Overpressure Exposure
Frontiers in neurology, 2019Co-Authors: Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Alejandro N. Ramos, Michael J. Egnoto, Walter Carr, Gary H. KamimoriAbstract:Addressing the concerns surrounding Blast injury for the military community is a pressing matter. Specifically, sub-concussive Blast effects, or those Blast effects which do not yield a medical diagnosis but can result in symptom reporting and negative self-reported outcomes, are becoming increasingly important. This work evaluates explosive Blast Overpressure and impulse effects at the sub-concussive level on neurocognitive performance assessed with the Defense Automated Neurobehavioral Assessment (DANA) across seven breacher training courses conducted by the US Military. The results reported here come from 202 healthy, male military volunteer participants. Findings indicate that the neurocognitive task appearing most sensitive to identifying performance change is the DANA Procedural Reaction Time (PRT) subtask which may involve a sufficient level of challenge to reliably detect a small, transient cognitive impairment among a healthy undiagnosed population. The Blast characteristic that was consistently associated with performance change was peak Overpressure. Overall, this study provides evidence that increasing Blast Overpressure, defined as peak Overpressure experienced in a training day, can lead to transient degradations in neurocognitive performance as seen on the DANA PRT subtask, which may generalize to other capabilities.
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The Role of Very Low Level Blast Overpressure in Symptomatology.
Frontiers in neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (
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the role of very low level Blast Overpressure in symptomatology
Frontiers in Neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (<3psi) associated with these exposures has largely been ignored. Notably, the current vLLB or acoustic literature has focused exclusively on auditory defects, and has not addressed the broader concerns of Soldier health and readiness. This work was prompted by reports of symptomatology such as headache, nausea, slowed reaction time, and balance/hearing complications among personnel undergoing frequent exposures to low Overpressure accompanied by high acoustic pressures. To more fully address the consequences associated with low Overpressure exposures (<3psi), a pilot proof-of-concept study was implemented, and data was acquired at two sites on the Fort Benning grenade course range. Findings indicated Overpressures ranged from 0.14-0.42 psi (0.97 – 2.89 kPa) at range 1 and 0.22 – 0.30 psi (1.52 – 2.07 kPa) on range 2 of the grenade course. Corresponding sound-meter data varied from 153.72 - 163.22 dBP. Headache and long think were the most frequently reported symptoms (3/6 instructors), with lightheadedness, ringing of the ears, restlessness, frustration, and irritability also increasing in 2/6 of the instructors post exposure. Long think (prolonged thinking), ringing of the ears, restlessness, and irritability were the most severe symptoms, with the highest reported post exposure value rating a 3 on the 0-4-point scale. We demonstrate that low-level repeated Overpressure exposure can result in transient symptomatology that overlaps with sub-concussive like effects.
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Shooter-experienced Blast Overpressure in .50-caliber rifles
Journal of special operations medicine : a peer reviewed journal for SOF medical professionals, 2018Co-Authors: Mark Lang, Christina R. Lavalle, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Gary H. Kamimori, Michael J. EgnotoAbstract:Background Increasingly, military and law enforcement are using .50-caliber rifles for conflict resolution involving barricades, armor, vehicles, and situations that require increased kinetic energy. Consequences to the shooter resulting from the Blast produced while firing these rifles remain unknown. We measured Blast Overpressure (OP) and impulse across various positions, environments, and weapon configurations to evaluate Blast exposures to shooters. Methods Two separate, multiday, .50-caliber rifle training courses were evaluated to understand the Blast exposure profile received from various tactical training scenarios, such as different firing positions (e.g., standing, prone, seated, kneeling) and locations (e.g., inside and atop vehicles, inside buildings, on hard/soft surfaces) across a variety of .50-caliber rifles with various barrel lengths, muzzle devices, and ammunition. Blackbox Biometrics, Generation 6, gauges were placed on operators to measure incident Blast exposure. A total of 444 rounds fired from various .50-caliber rifles were evaluated to determine what OP was received by 32 different shooters. Results Our findings indicate OPs >4 psi are common and that muzzle devices are critical to Blast exposure. Shooting positions closer to the ground experienced higher OP and impulse than did other positions. Suppressors mitigated Blast effects well. Conclusion When resources and operational parameters allow, suppressors are recommended, as are positions that move the shooter farther from reflective surfaces (standing preferred) to effectively reduce Blast exposure. These shooter positions may require the use of supplemental rifle rests/tripods to provide sufficiently stable firing platforms from the standing position.
Christina R. Lavalle - One of the best experts on this subject based on the ideXlab platform.
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Neurocognitive Performance Deficits Related to Immediate and Acute Blast Overpressure Exposure
Frontiers in neurology, 2019Co-Authors: Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Alejandro N. Ramos, Michael J. Egnoto, Walter Carr, Gary H. KamimoriAbstract:Addressing the concerns surrounding Blast injury for the military community is a pressing matter. Specifically, sub-concussive Blast effects, or those Blast effects which do not yield a medical diagnosis but can result in symptom reporting and negative self-reported outcomes, are becoming increasingly important. This work evaluates explosive Blast Overpressure and impulse effects at the sub-concussive level on neurocognitive performance assessed with the Defense Automated Neurobehavioral Assessment (DANA) across seven breacher training courses conducted by the US Military. The results reported here come from 202 healthy, male military volunteer participants. Findings indicate that the neurocognitive task appearing most sensitive to identifying performance change is the DANA Procedural Reaction Time (PRT) subtask which may involve a sufficient level of challenge to reliably detect a small, transient cognitive impairment among a healthy undiagnosed population. The Blast characteristic that was consistently associated with performance change was peak Overpressure. Overall, this study provides evidence that increasing Blast Overpressure, defined as peak Overpressure experienced in a training day, can lead to transient degradations in neurocognitive performance as seen on the DANA PRT subtask, which may generalize to other capabilities.
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The Role of Very Low Level Blast Overpressure in Symptomatology.
Frontiers in neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (
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the role of very low level Blast Overpressure in symptomatology
Frontiers in Neurology, 2019Co-Authors: Venkata Siva Sai Sujith Sajja, Joseph B Long, Christina R. Lavalle, Jonathan E. Salib, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Michael J. Egnoto, Gary H. KamimoriAbstract:Blast Overpressure exposure has been linked to transient, but measurably deteriorated performance and symptomatologies in law enforcement/military personnel. Overlapping sub-concussive symptomatology associated with the very low level Blast Overpressures (vLLB) but high sound pressure (<3psi) associated with these exposures has largely been ignored. Notably, the current vLLB or acoustic literature has focused exclusively on auditory defects, and has not addressed the broader concerns of Soldier health and readiness. This work was prompted by reports of symptomatology such as headache, nausea, slowed reaction time, and balance/hearing complications among personnel undergoing frequent exposures to low Overpressure accompanied by high acoustic pressures. To more fully address the consequences associated with low Overpressure exposures (<3psi), a pilot proof-of-concept study was implemented, and data was acquired at two sites on the Fort Benning grenade course range. Findings indicated Overpressures ranged from 0.14-0.42 psi (0.97 – 2.89 kPa) at range 1 and 0.22 – 0.30 psi (1.52 – 2.07 kPa) on range 2 of the grenade course. Corresponding sound-meter data varied from 153.72 - 163.22 dBP. Headache and long think were the most frequently reported symptoms (3/6 instructors), with lightheadedness, ringing of the ears, restlessness, frustration, and irritability also increasing in 2/6 of the instructors post exposure. Long think (prolonged thinking), ringing of the ears, restlessness, and irritability were the most severe symptoms, with the highest reported post exposure value rating a 3 on the 0-4-point scale. We demonstrate that low-level repeated Overpressure exposure can result in transient symptomatology that overlaps with sub-concussive like effects.
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Brain-related proteins as serum biomarkers of acute, subconcussive Blast Overpressure exposure: A cohort study of military personnel.
PloS one, 2019Co-Authors: Angela M. Boutté, Christina R. Lavalle, Bharani Thangavelu, Jeffrey Nemes, Janice S. Gilsdorf, Deborah A. Shear, Gary H. KamimoriAbstract:Repeated exposure to Blast Overpressure remains a major cause of adverse health for military personnel who, as a consequence, are at a higher risk for neurodegenerative disease and suicide. Acute, early tracking of Blast related effects holds the promise of rapid health assessment prior to onset of chronic problems. Current techniques used to determine Blast-related effects rely upon reporting of symptomology similar to that of concussion and neurocognitive assessment relevant to operational decrement. Here, we describe the results of a cross sectional study with pared observations. The concentration of multiple TBI-related proteins was tested in serum collected within one hour of Blast exposure as a quantitative and minimally invasive strategy to augment assessment of Blast-exposure effects that are associated with concussion-like symptomology and reaction time decrements. We determined that median simple reaction time (SRT) was slowed in accordance with serum Nf-L, tau, Aβ-40, and Aβ-42 elevation after Overpressure exposure. In contrast, median levels of serum GFAP decreased. Individual, inter-subject analysis revealed positive correlations between changes in Nf-L and GFAP, and in Aβ-40 compared to Aβ-42. The change in Nf-L was negatively associated with tau, Aβ-40, and Aβ-42. Participants reported experiencing headaches, dizziness and taking longer to think. Dizziness was associated with reaction time decrements, GFAP or NfL suppression, as well as Aβ peptide elevation. UCH-L1 elevation had a weak association with mTBI/concussion history. Multiplexed serum biomarker quantitation, coupled with reaction time assessment and symptomology determined before and after Blast exposure, may serve as a platform for tracking adverse effects in the absence of a head wound or diagnosed concussion. We propose further evaluation of serum biomarkers, which are often associated with TBI, in the context of acute operational Blast exposures.
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Shooter-experienced Blast Overpressure in .50-caliber rifles
Journal of special operations medicine : a peer reviewed journal for SOF medical professionals, 2018Co-Authors: Mark Lang, Christina R. Lavalle, Anthony Misistia, Meron Y. Ghebremedhin, Alejandro N. Ramos, Gary H. Kamimori, Michael J. EgnotoAbstract:Background Increasingly, military and law enforcement are using .50-caliber rifles for conflict resolution involving barricades, armor, vehicles, and situations that require increased kinetic energy. Consequences to the shooter resulting from the Blast produced while firing these rifles remain unknown. We measured Blast Overpressure (OP) and impulse across various positions, environments, and weapon configurations to evaluate Blast exposures to shooters. Methods Two separate, multiday, .50-caliber rifle training courses were evaluated to understand the Blast exposure profile received from various tactical training scenarios, such as different firing positions (e.g., standing, prone, seated, kneeling) and locations (e.g., inside and atop vehicles, inside buildings, on hard/soft surfaces) across a variety of .50-caliber rifles with various barrel lengths, muzzle devices, and ammunition. Blackbox Biometrics, Generation 6, gauges were placed on operators to measure incident Blast exposure. A total of 444 rounds fired from various .50-caliber rifles were evaluated to determine what OP was received by 32 different shooters. Results Our findings indicate OPs >4 psi are common and that muzzle devices are critical to Blast exposure. Shooting positions closer to the ground experienced higher OP and impulse than did other positions. Suppressors mitigated Blast effects well. Conclusion When resources and operational parameters allow, suppressors are recommended, as are positions that move the shooter farther from reflective surfaces (standing preferred) to effectively reduce Blast exposure. These shooter positions may require the use of supplemental rifle rests/tripods to provide sufficiently stable firing platforms from the standing position.