United States Army Special Operations Command, Fort Liberty, NC 28310, USA.
CU Anschutz Center for COMBAT Research, Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA.
Mil Med. 2024 Aug 30;189(9-10):e2069-e2077. doi: 10.1093/milmed/usae082.
Cumulative low-level blast exposure during military training may be a significant occupational hazard, increasing the risk of poor long-term outcomes in brain function. US Public Law 116-92 section 717 mandates that US Department of Defense agencies document the blast exposure of each Service member to help inform later disability and health care decisions. However, which empirical measures of training blast exposure, such as the number of incidents, peak overpressure, or impulse, best inform changes in the neurobehavioral symptoms reflecting brain health have not been established.
This study was approved by the US Army Special Operations Command, the University of North Carolina at Chapel Hill, and the VA Puget Sound Health Care System. Using methods easily deployable across different organizational structures, this study sought to identify and measure candidate risk factors related to career occupational blast exposure predictive of changes in neurobehavioral symptom burden. Blast dosimetry-symptom relationships were first evaluated in mice and then tested in a military training environment. In mice, the righting time neurobehavioral response was measured after exposure to a repetitive low-level blast paradigm modeled after Special Operations training. In the military training environment, 23 trainees enrolled in a 6-week explosive breaching training course, 13 instructors, and 10 Service member controls without blast exposure participated in the study (46 total). All participants provided weekly Neurobehavioral Symptom Inventory (NSI) surveys. Peak blast overpressure, impulse, total number of blasts, Time in Low-Level Blast Occupation, and Time in Service were analyzed by Bayesian analysis of regression modeling to determine their probability of influence on the post-training symptoms reported by participants.
We tested the hypothesis that cumulative measures of low-level blast exposure were predictive of changes in neurobehavioral symptoms. In mice, repetitive blast resulted in reduced righting times correlated with cumulative blast impulse. In Service members, peak blast overpressure, impulse, total number of blasts, Time in Low-Level Blast Occupation, and Time in Service all showed strong evidence of influence on NSI scores after blast exposure. However, only models including baseline NSI scores and cumulative blast impulse provided significant predictive value following validation.
These results indicate that measures of cumulative blast impulse may have utility in predicting changes in NSI scores. Such paired dosimetry-symptom measures are expected to be an important tool in safely guiding Service members' occupational exposure and optimizing force readiness and lethality.
在军事训练中累积的低水平爆炸暴露可能是一个重大的职业危害，增加了大脑功能长期不良结局的风险。美国公法 116-92 第 717 条规定，美国国防部各机构必须记录每位军人的爆炸暴露情况，以帮助了解以后的残疾和医疗保健决策。然而，哪种培训爆炸暴露的经验测量方法（如事件次数、峰值超压或脉冲）最能反映反映大脑健康的神经行为症状的变化，尚未确定。
本研究得到了美国特种作战司令部、北卡罗来纳大学教堂山分校和 VA 普吉特湾医疗保健系统的批准。本研究使用易于在不同组织结构中部署的方法，旨在确定和测量与职业爆炸暴露相关的候选风险因素，这些因素可预测神经行为症状负担的变化。首先在小鼠中评估爆炸剂量-症状关系，然后在军事训练环境中进行测试。在小鼠中，暴露于重复低水平爆炸模型后，测量右侧时间神经行为反应，该模型模拟了特种作战训练。在军事训练环境中，23 名学员参加了为期 6 周的爆炸突破训练课程，13 名教官和 10 名没有爆炸暴露的军人控制组参加了研究（共 46 人）。所有参与者每周提供神经行为症状清单（NSI）调查。通过贝叶斯回归模型分析，对峰值爆炸超压、脉冲、爆炸总数、低水平爆炸作业时间和服役时间进行分析，以确定它们对参与者报告的训练后症状的影响概率。
我们检验了这样一个假设，即累积的低水平爆炸暴露量与神经行为症状的变化有关。在小鼠中，重复爆炸导致的右侧时间减少与累积爆炸脉冲相关。在军人中，峰值爆炸超压、脉冲、爆炸总数、低水平爆炸作业时间和服役时间在暴露于爆炸后，对 NSI 评分均显示出强烈的影响证据。然而，只有包括基线 NSI 评分和累积爆炸脉冲的模型在验证后提供了显著的预测价值。
这些结果表明，累积爆炸脉冲的测量方法可能对预测 NSI 评分的变化有用。这种剂量-症状配对测量预计将成为安全指导军人职业暴露、优化部队准备状态和杀伤力的重要工具。
