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ClinicalTrials.gov ID

NCT07606651

Lead Sponsor

Uniformed Services University of the Health SciencesFED

Overall Status

Not yet recruiting

Study Type

Observational

Enrollment

250Estimated

Last Update Posted

May 26, 2026Actual

Start Date

May 2026Estimated

Primary Completion Date

Aug 2030Estimated

Completion Date

Aug 2030Estimated

Official Title

Blast Overpressure Longitudinal Exposure Study (BLES)

Brief Summary

The goal of this observational study is to learn about the impact of low-level blast exposure in U.S. Special Operations Forces personnel. The main questions it aims to answer are:

What advanced brain imaging changes are related to clinical presentation after low-level blast exposure? What are the relationships between low-level blast exposure and common groups of symptoms after concussion?

Participants will:

• Undergo advanced brain imaging
• Answer questionnaires
• Complete clinical tests
• Provide blood, urine, and saliva samples
• Wear blast sensors

Detailed Description

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.

• Low-level Blast Exposure

Ages Eligible for Study

Adult (18-64)

Sexes Eligible for Study

All

Accepts Healthy Volunteers

Yes

Eligibility Criteria

Inclusion Criteria:

• Active duty
• U.S. SOF personnel
• 18-50 years old

Exclusion Criteria:

• Subjects will be excluded only if their participation will significantly interfere with validity of data collection or safety during the study (e.g., they have conditions that might result in harm or injury during research procedures).
• Example: pregnancy (balance considerations)
• Example: being unable to undergo MRI testing (i.e., they have non-MRI compatible devices, imbedded metal fragments such as shrapnel, and/or severe claustrophobia; these MRI contraindications will be screened using an MRI Safety Questionnaire)

Observational Model

Cohort

Time Perspective

Prospective

Lead Sponsor

Uniformed Services University of the Health SciencesFED

Collaborators

The Geneva FoundationOTHER

MIT Lincoln LaboratoryUNKNOWN

rodney.saunders.ctr@usuhs.edu740-398-1391