Impact of Repetitive Blast Exposure on Military Health and Performance –Multinational Efforts and Guidelines


Lt(N) Peter Beliveau, DC, MSc1, Dr. Shawn G. Rhind, PhD2, Dr. Oshin Vartanian, PhD2, Dr. Thuvan Piehler, PhD3,4, MAJ Stephen Krauss, PhD3, and Dr. Mattias K. Sköld, MD. PhD5,6

  1. Canadian Armed Forces, Department of National Defence, Ottawa ON, Canada
  2. Defence Research and Development Canada, Toronto Research Centre, Toronto ON, Canada
  3. US Medical Research Development and Command, Ft. Detrick, Maryland, USA
  4. US Army Research Laboratory, Aberdeen Proving Ground, Maryland, USA
  5. Department of Neuroscience, Experimental Traumatology Unit, Karolinska Institute, Stockholm, Sweden
  6. Department of Neurosurgery, Uppsala University Hospital, Uppsala, Sweden
Military populations face a unique set of occupational risk factors that may impact brain integrity and disrupt neurological function. One such risk factor is blast exposure, which can cause many types of injuries through repeated low-level overpressure exposure (i.e., low-level blast), intense overpressure exposure (i.e., high-level blast), muzzle blast exposure from firing weapons, and blunt trauma. Although the precise mechanism(s) of injury remains unknown, there is growing evidence to suggest that the effects of repeated low level blast overpressure extend beyond the brain to also impact other organ systems such as the lungs, eyes, and ears.  Currently, blast-induced subconcussive neurotrauma and diagnosed traumatic brain injury (TBI) are increasingly recognized injury risks for Warfighters, and growing body of evidence to suggest that cumulative blast exposure is a significant risk factor for developing negative long-term brain and body health effects. Within this context, brain health is defined as a state of optimal physical, mental, and social wellbeing, in the absence of overt brain diseases that affect normal brain function.  
Military service members, former or retired military members, and Veterans with a history of repetitive neurotrauma – including symptomatic concussions, mild TBI, or repeated subconcussive impacts from exposure to low-intensity explosive blast waves – exhibit measurable performance decrements and adverse health outcomes. These range from persistent headaches, irritability, impairments in learning and memory, gait, balance and hearing problems, progressive neurodegenerative symptoms, and a higher prevalence/severity of mental health disorders (i.e., post traumatic stress disorder, depression, suicidal ideation) relative to civilians as well as sex- and age-matched controls drawn from military populations without such exposures. These conditions can degrade operational readiness and limit reintegration.
There are currently no standardized biologic or performance marker(s) for the diagnosis of the effects of repeated low-level or high-level blast overpressure on military members’ and Veterans’ health, although valid and reliable measures are beginning to emerge. Awareness of the risk of exposure to blast overpressure has increased due to current training tactics, missions, and operations. To reduce the risk of developing negative brain health effects from blast overpressure, Warfighters can benefit significantly from the implementation of exposure guidelines to monitor and control the exposure to blast in the course of their careers. Such multinational guidelines should ideally be constructed to assist in understanding and mitigating blast exposure effects in everyday military activities spanning both training and operations.
In summary, exposure to blast overpressure is a persistent feature of combat-related injuries experienced by military personnel. In addition to combat-related blast injuries, concerns exists that repeated exposures to low-level blasts during routine training and operations may be linked to long-term neurological sequelae. These concerns have driven research exploring cumulative injury mechanisms following repeated blast exposure. Molecular and neuroimaging techniques present distinct but complementary approaches for investigating brain health/injury and have yielded potential biomarkers. Integration of these multimodal technologies in combination with data-driven artificial intelligence-enabled machine learning-based data analytic techniques could advance models of disease pathobiology and prognosis, ultimately improving prevention and precision care for subconcussive neurotrauma. To prevent and potentially treat these common injuries, it is imperative to enhance understanding of blast effects, monitor blast exposures in both training and in operational environments, and mitigate brain dysfunction in order to optimize health and performance, thereby, preserving readiness and after-service life for Veterans.  
The objectives of the workshop are to discuss a) prospective cross-sectional comparisons and longitudinal data, collected from service members and Veterans who have sustained extensive operational exposures to repetitive subconcussive neurotrauma (e.g., explosive blast, weapons systems), during rigorous military training exercises and/or operational war-zone deployments vs. healthy cohorts, b) advanced structural and functional neuroimaging techniques to evaluate brain network integrity and functional connectivity; c) wearable concussion dosimeter technologies and gaps in their capability to monitor biological and cognitive performance changes in training and operations; d) multinational guidelines of blast monitoring implementation to mitigate blast exposure risk to Warfighters; e) blast-specific medical intervention, and f) future research direction to assist policy makers and researchers to further develop the field of blast-induced TBI as efficiently and effectively as possible.
This workshop would include a brief overview of the scope of the problem of low-intensity repetitive blast in military health and performance, state of science research from preclinical to clinal findings of blast exposure health effects, and some recommendation on mitigation guidelines.The workshop will bring at least 5 to 6 international cross-disciplinary subject matter experts with a broad knowledge and expertise on preclinical to clinical blast injury research, and with a synopsis at the end by the workshop co-chairs.
The intended audience are clinicians, military medical personnel, academic and defence scientists, industry, health care policy advisors.