title: Repeated Low-Level Blast Exposure: A Descriptive Human Subjects Study.
abstract: The relationship between repeated exposure to blast overpressure and neurological function was examined in the context of breacher training at the U.S. Marine Corps Weapons Training Battalion Dynamic Entry School. During this training, Students are taught to apply explosive charges to achieve rapid ingress into secured buildings. For this study, both Students and Instructors participated in neurobehavioral testing, blood toxin screening, vestibular/auditory testing, and neuroimaging. Volunteers wore instrumentation during training to allow correlation of human response measurements and blast overpressure exposure. The key findings of this study were from high-memory demand tasks and were limited to the Instructors. Specific tests showing blast-related mean differences were California Verbal Learning Test II, Automated Neuropsychological Assessment Metrics subtests (Match-to-Sample, Code Substitution Delayed), and Delayed Matching-to-Sample 10-second delay condition. Importantly, apparent deficits were paralleled with functional magnetic resonance imaging using the n-back task. The findings of this study are suggestive, but not conclusive, owing to small sample size and effect. The observed changes yield descriptive evidence for potential neurological alterations in the subset of individuals with occupational history of repetitive blast exposure. This is the first study to integrate subject instrumentation for measurement of individual blast pressure exposure, neurocognitive testing, and neuroimaging.
authors.affiliation: Department of Behavioral Biology, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910.
authors.forename: Walter
authors.initials: W
authors.lastname: Carr
authors.affiliation: University of Virginia Health System, 480 Ray C. Hunt Drive, Room 281, Box 801339, Charlottesville, VA 22903.
authors.forename: James R
authors.initials: JR
authors.lastname: Stone
authors.affiliation: Applied Research Associates, Inc., 7921 Shaffer Parkway, Littleton, CO 80127.
authors.forename: Tim
authors.initials: T
authors.lastname: Walilko
authors.affiliation: Applied Research Associates, Inc., 950 Isom Road, San Antonio, TX 78216.
authors.forename: Lee Ann
authors.initials: LA
authors.lastname: Young
authors.affiliation: University of Virginia Health System, 480 Ray C. Hunt Drive, Room 281, Box 801339, Charlottesville, VA 22903.
authors.forename: Tianlu Li
authors.initials: TL
authors.lastname: Snook
authors.affiliation: Weill Cornell Medical College, 21 Bloomingdale Road, White Plains, NY 10605.
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Paggi
authors.affiliation: Traumatic Brain Injury Programs, U.S. Navy Bureau of Medicine and Surgery, 2300 East Street Northwest, Washington, DC 20372-5300.
authors.forename: Jack W
authors.initials: JW
authors.lastname: Tsao
authors.affiliation: Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Jankosky
authors.affiliation: MEDCOM Irwin Army Community Hospital, 600 Caisson Hill Road, Fort Riley, KS 66442.
authors.forename: Robert V
authors.initials: RV
authors.lastname: Parish
authors.affiliation: Operational and Undersea Medicine, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Ahlers
mesh_terms: D000328:Adult; D001753:Blast Injuries / Q000150:complications* / Q000503:physiopathology; D005107:Explosions; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008889:Military Personnel / Q000523:psychology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D057566:Self Report; D011795:Surveys and Questionnaires; D013663:Teaching; D000078329:Workforce