The Effects of Chronic Exposure to Low-Level Blasts

Study Summary

Background: \- Repeated exposure to explosions may lead to changes in the way that people think or feel. Breachers (people trained to use explosives to get into buildings) are exposed to repeated blasts as part of their job. Researchers want to study how they might be affected by blast exposure. Breachers will be compared with other groups who have different levels of exposure to repeated blasts. Information will also be obtained from spouses or close companions. Objectives: \- To study the effects of repeated exposure to low-level blasts on thinking, memory, behavior, and brain function. Eligibility: * Experienced military and civilian breachers, experienced active duty artillery operators, and active duty military without frequent blast exposure, 18 and 60 years of age. * Spouses or close companions of these individuals. Design: * Participants will be screened with a physical exam and medical history. Blood samples will be collected and a urine pregnancy test will be required of participants (not companions) before MRI scanning. * Participants will spend up to 5-days as a NIH clinic outpatient, with about 6 hours of tests each day. Tests will include the following: * Medical and professional history, with questions about exposures to blasts * Tests of thinking, memory, and concentration * Balance tests * Hearing tests * Imaging studies, such as magnetic resonance imaging, to look at the brain * Overnight sleep study to monitor brain waves * Blood samples * Participants will return 1 year later for a 3-day followup visit. Some of the tests from before will be repeated. A spouse or close companion (if available) will be asked to complete questionnaires or have a telephone interview....