Uniformed Services University of the Health Sciences
4301 Jones Bridge Road
Bethesda, Maryland 20814
MEM Office: C1039
Phone (301) 295-3720
Toll Free: (888) 826-3126
FAX (301) 295-6773
The Traumatic Injury Research Program's (TIRP) electromagnetically shielded EEG/ERP facility was designed in collaboration with engineers at VitaTech Corporation, who constructed the facility in 2008. There are multiple layers of EM shielding, autonomous control of ventilation, and all alternating current sources have been eliminated form the chamber; illumination is provided by DC-powered light emitting diodes. TIRP is now working in collaboration with Sensorium, Inc. to develop field-deployable EEG/ERP systems. Two digital amplifier systems constructed to our specifications will be delivered in 2009. In contrast with previous systems developed for quantitative electroencephalography, a digital amplifier has the amplifier and digitizer on the same board. The transition to digital amplifier technology offers advantages of improved robustness and enhanced signal quality. Initial tests of these units will be conducted in our laboratory. Subsequent testing will be integrated into Operation Bushmaster, the Uniformed Services University's field training exercise.
Subtle early stage deficits in central nervous system status in response to fatigue, mild traumatic brain injury, exposure to toxic agents or psychological stress may first become evident in nonconscious cognitive processing, specifically in the processing of peri-threshold (subliminal) visual stimuli. There are two experimental procedures for producing marginally perceptible visual stimuli: tachistoscopic presentation and backward masking. The classical mechanical tachistoscope is not suitable for field deployment. This requirement motivated the design and construction of a digital tachistoscope formed by a matrix of light emitting diodes. The Mark I system is now being tested, and design discussions for the Mark II have begun.
Though the limitations of neuropsychological testing in the diagnosis of mild traumatic brain injury are recognized, these procedures are, and will remain, important in early identification and longitudinal monitoring of head trauma patients. As the result of technology developed in response to DoD research initiatives, these tests are now routinely administered by computer. The development of a fully integrated system combining quantitative EEG, event-related potentials and neuropsychological testing as menu options in a single field-deployable system is an objective of this program. Collaborative engineering work is now underway.