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Chronic low-level blast exposure has been linked with neurological alterations and traumatic brain injury (TBI) biomarkers. Impaired smooth-pursuit eye movements (SPEM) are often associated with TBI. The purpose of this study was to determine whether long-term operators of low-level blast exposure or high-caliber weapons use displayed oculomotor be...
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... linear combination of Fixation Percentage and Saccadic Velocity was significantly related to the TBI status, χ 2 = 14.109; p < 0.01, R 2 = 0.459. The other predictors did not significantly contribute to the model and were removed (see Table 4). The final model accurately predicted 84.6% of the TBI status, with a sensitivity of 94% and specificity of 63%. ...Similar publications
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... These injuries involve mechanical deformation of blood vessels, transient or persistent blood-brain barrier (BBB) disruption, vasospasm, and microhemorrhages, all of which may remain subclinical but accumulate over time [9,[22][23][24][25][26][27][28]. Findings from both clinical and experimental work indicate a continuum of blast-related pathophysiology, wherein repeated low-intensity insults can induce immediate subclinical disturbances that progress to overt and persistent neurological damage [29][30][31][32][33][34][35]. Each additional exposure appears to heighten the brain's vulnerability to further injury and diminish its recovery capacity [11,17,36,37], placing those who experience frequent blasts at a substantially increased risk of chronic functional deficits and eventual progression to neurodegenerative conditions [38,39]. ...
Repeated exposure to low-level blast overpressure, frequently experienced during explosive breaching and heavy weapons use in training and operations, is increasingly recognised as a serious risk to the neurological health of military personnel. Although research on the underlying pathobiological mechanisms in humans remains limited, this study investigated the effects of such exposure on circulating molecular biomarkers associated with inflammation, neurovascular damage, and endothelial injury. Blood samples from military breachers were analysed for myeloperoxidase (MPO), matrix metalloproteinases (MMPs), and junctional proteins indicative of blood–brain barrier (BBB) disruption and endothelial damage, including occludin (OCLN), zonula occludens-1 (ZO-1), aquaporin-4 (AQP4), and syndecan-1 (SD-1). The results revealed significantly elevated levels of MPO, MMP-3, MMP-9, and MMP-10 in breachers compared to unexposed controls, suggesting heightened inflammation, oxidative stress, and vascular injury. Increased levels of OCLN and SD-1 further indicated BBB disruption and endothelial glycocalyx degradation in breachers. These findings highlight the potential for chronic neurovascular unit damage/dysfunction from repeated blast exposure and underscore the importance of early targeted interventions—such as reducing oxidative stress, reinforcing BBB integrity, and managing inflammation—that could be essential in mitigating the risk of long-term neurological impairment associated with blast exposure.
... highlights the cumulative and insidious effects of repeated low-level blast exposure on the central nervous system (CNS) [6][7][8][9][10][11]. Chronic exposure to blast waves is associated with transient neurological symptoms as well as enduring structural and functional brain changes, contributing to persistent neuroinflammation, long-term cognitive impairments, and an elevated risk of neurodegenerative conditions [12][13][14][15][16][17][18]. An emerging focus in neurotrauma research is the role of autoantibodies targeting brain-specific proteins-such as glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), and pituitary (PIT) antigens-in the pathophysiology of repetitive head impacts and blast-induced neurotrauma [19][20][21][22][23][24][25][26][27]. ...
Military breachers are routinely exposed to repetitive low-level blast overpressure, placing them at elevated risk for long-term neurological sequelae. Mounting evidence suggests that circulating brain-reactive autoantibodies, generated following CNS injury, may serve as both biomarkers of cumulative damage and drivers of secondary neuroinflammation. In this study, we compared circulating autoantibody profiles in military breachers (n = 18) with extensive blast exposure against unexposed military controls (n = 19). Using high-sensitivity immunoassays, we quantified IgG and IgM autoantibodies targeting glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), and pituitary (PIT) antigens. Breachers exhibited significantly elevated levels of anti-GFAP IgG (p < 0.001) and anti-PIT IgG (p < 0.001) compared to controls, while anti-MBP autoantibody levels remained unchanged. No significant differences were observed for any IgM autoantibody measurements. These patterns suggest that repetitive blast exposure induces a chronic, adaptive immune response rather than a short-lived acute phase. The elevated IgG autoantibodies highlight the vulnerability of astrocytes, myelin, and the hypothalamic–pituitary axis to ongoing immune-mediated injury following repeated blast insults, likely reflecting sustained blood–brain barrier disruption and neuroinflammatory processes. Our findings underscore the potential of CNS-targeted IgG autoantibodies as biomarkers of cumulative brain injury and immune dysregulation in blast-exposed populations. Further research is warranted to validate these markers in larger, more diverse cohorts, and to explore their utility in guiding interventions aimed at mitigating neuroinflammation, neuroendocrine dysfunction, and long-term neurodegenerative risks in military personnel and similarly exposed groups.
Background Oculomotor and reaction time tests are frequently used assessments of vestibular symptoms, traumatic brain injury (TBI), or other neurological disorders in both clinical and research contexts. When interpreting these tests it is important to have a reference interval (RI) as a comparison for what constitutes a typical/expected response; however, the current body of research has only limited information regarding normative ranges calculated according to established standards or for a military-specific sample.
Purpose The purpose of the present study was to describe RIs for oculomotor and reaction time tests in a cohort of service members and veterans (SMVs) for use as comparators by clinicians and scientists.
Research Design Descriptive.
Study Sample Participants were prospectively enrolled in the Defense and Veterans Brain Injury Center-Traumatic Brain Injury Center of Excellence 15-year Longitudinal Traumatic Brain Injury Study. Only SMVs without a history of TBI or blast exposure were included in the RI calculations.
Data Collection and Analysis The test paradigms included in this analysis were: smooth pursuit, prosaccades, antisaccades, saccades and reaction time, predictive saccades, optokinetic nystagmus, auditory reaction time, and visual reaction time. Nonparametric methods, based on the U.S. Food and Drug Administration's recognized consensus standards, were used to calculate 95% RIs. A comparison between the calculated RIs and those available from previously published research is provided.
Results Summary statistics and RIs were calculated for 47 outcome parameters from 13 oculomotor and reaction time tests. Sample sizes and age ranges varied across outcome parameters depending on the availability of reference values for RI calculations. The sample sizes used to calculate RIs ranged from 51 to 69. The age of SMVs included in each RI ranged from 19 to 61 years with mean ages ranging from 37 to 39 years. Similarities/differences between the RIs in the present study and those in previously published research are highly dependent on the outcome parameter; however, in general, the RIs in the present study tended to be somewhat wider.
Conclusions The RIs provided in this paper can serve as comparisons for clinicians and scientists who are utilizing these oculomotor and reaction time testing paradigms in similar cohorts of patients or research participants.
