Case Study of a Breacher: Investigation of Neurotrauma Biomarker Levels, Self-reported Symptoms, and Functional MRI Analysis Before and After Exposure to Measured Low-Level Blast.

We report a case study on a single military member who received moderate blast overpressure (OP) exposure during routine breacher training. We extend previous research on blast exposure during training, which lacked sufficient data to assess symptom profiles and OP exposure. The present work was conducted because a subjective symptom profile similar to that seen in sports concussion has been reported by military personnel exposed to blast. Data collection for this study was carried out under a research protocol approved by the relevant Human Subjects Review Committees on one subject, who received the highest OP exposure during training. The volunteer was a 20-year-old male with no prior history of traumatic brain injury (TBI) or blast exposure. The volunteer was part of a breacher training team that completed a 2-week explosive entry course. The course included 3 classroom days and 9 days of practical training, held in the morning, afternoon, and evening sessions. Blast exposure occurred on five of the nine practical training days, with multiple exposures over the course of each day. Assessments of serum, self-reported symptoms, magnetic resonance imaging, and blast characterization were conducted. Results indicated changes in glial fibrillary acidic protein and ubiquitin C-terminal hydrolase-L1 postblast exposure but did not manifest changes in spectrin-derived breakdown product 150 or magnetic resonance imaging. No additional symptoms were reported by the subject. Objective markers of mild TBI remain elusive, but support for serum biomarkers as an early detection mechanism is promising. Additionally, this case study demonstrated an association between OP and high level of neurotrauma biomarker in an individual.