Blast Overpressure Longitudinal Exposure Study (BLES)

Participants in this observational study are active-duty U.S. Special Operations Forces personnel between the ages of 18 and 50. This study is designed to characterize the neurological and clinical effects associated with repeated low-level blast exposure (LLBE) in this population. Concerns have emerged that cumulative exposure to sub-concussive blast overpressure (BOP), even in the absence of a diagnosable concussion, may be associated with subtle changes in brain structure and function over time. Due to the nature of their operational and training environments, Special Operations Forces personnel may experience repeated LLBE and are therefore an important population for longitudinal investigation.

Participation involves in-person assessments and data collection conducted over a period of approximately 4-5 years. The schedule of study activities includes baseline, daily, weekly, monthly, quarterly, and annual assessments. Baseline and annual study visits include advanced magnetic resonance imaging (MRI) and require travel to Walter Reed National Military Medical Center. Specifically, this study includes the use of the Microstructure Anatomy Gradient for Neuroimaging with Ultrafast Scanning (MAGNUS) 3.0 Tesla MRI.

Throughout the study period, participants complete standardized questionnaires and clinical assessments and provide biological samples, including blood, urine, and saliva, at specified intervals. Participants also contribute measures on a daily, weekly, monthly, quarterly, and annual basis. They will wear blast sensors throughout their participation in the study.

The total planned enrollment for the study is approximately 250 participants across multiple sites, with an estimated 60 participants enrolled at Fort Bragg, NC. Enrollment and follow-up are expected to occur over a 4-5 year period.