According to the Defense and Veterans Brain Injury Center established by Congress, 188,270 service members have suffered a traumatic brain injury in the last decade. the extent of injury is often difficult to discern, making diagnosis and selection of appropriate medical treatment challenging.
When a solider is exposed to a blast, shockwaves can cause a series of complex mechanical and physical reactions in the brain. These blast waves can induce tissue strains and stress, which may result in brain damage. Currently, no experimental data for humans exists to correlate pressure and stress on the brain with an actual explosive event that could assist with predicting brain injury. Through an effort funded by the Defense Advance Research Projects Agency (DARPA), a team of RIT engineers has responded to this critical need by designing, engineering, and testing a blast measurement device that in the near future could be used to assist with field triage.
Dr. David Borkholder, associate professor of electrical and microelectronic engineering, assembled a project team consisting of Dr. Lynn Fuller, professor of electrical and microelectronic engineering; two senior engineers, Gary Parrett and Werner Fassler; a recent RIT engineering graduate, Matthew Waldron; and staff assistant JoEllyn Tufano. Andrew Blair, an Army ROTC cadet; Stefan Wojick, a former U.S. Marine; Aalyia Shaukat; and Sigitas Rimkus, all undergraduate engineering students, are also involved in the project, participating in design work as well as system testing.
To provide information for field triage and long-term care, the blast gauge measures pressure, +-axis head acceleration, and logs the time of the event. In addition, and perhaps even more challenging, the device is intended to be a disposable weighing less than one ounce and constructed from off-theshelf components. "To equip a mass of deployed soldiers, each carrying significant weight, it is critical the device be lightweight and disposable," explains Borkholder. "While the core technology exists, the challenge is customizing the capabilities through creative engineering and integrating the components into a single system that provides a practical solution for the military."
It's not as simple as knowing when a blast occurs and that a soldier was exposed. The impact and characteristics of a blast depend on the explosive itself and the physical environment and orientation of the soldier. Blast wave inter actions with structures can result in reflected waves, which influence overall exposure dose and resulting injury. Accurate measurement of full exposure coupled with integrated analysis algorithms provides specific information that may enable field triage immediately following an explosive event, and that may aid in determination of the most appropriate long-term treatment.
Another challenge addressed by the algorithm is determining when a true explosive event occurs. Acceleration events, as simple as dropping a helmet or tripping, could trigger a false event. The algorithm is able to distinguish and trigger on true blast events, thereby avoiding false triggers associated with acceleration. To protect the sensor from the environment and non-pressure events, while still allowing accurate measurement of the pressure waveform associated with explosive blast, the team designed a protective dome over the sensor, which was tooled in RIT's Mechanical Engineering Machine Shop by Robert Kraynik.
A microprocessor controls the device and integrates all commercially available components. The team developed an electrical architecture that effectively minimizes the components, which equates to savings in power, weight, and cost. Embedded so%ware interfaces with the sensors at speeds fast enough to capture the rapid blast events. Significant pressure changes occur in a few millionths of a second and the device needs to collect data, determine if it is a blast event, and store only real blast events. "Being able to collect this information continuously and at fast enough speeds was no trivial task," adds Borkholder.
Three light-emitting diode (LED) lights provide exposure information to the soldier while a micro-USB port allows a field medic the ability to download the data.
Initial prototyping was conducted using the Brinkman Machine Tools and Manufacturing Laboratory's 3-D printer. "This tool was especially helpful in quickly proto typing housings and mounting mechanisms." Kim Sherman, founder of Think Design and lecturer in industrial design, helped to refine the design and functionality of the device. The unit was designed with a "exible mounting system allowing comfortable attachment to the soldier's helmet, vest, or gear, and to physical structures such as within vehicle cabins.
Extensive explosive testing was conducted at RIT and in South Carolina at NEWTEC Services Group, Inc. At RIT, the team developed a safe way to create an explosive event using propane and oxygen. The constructed cannon generates pressure in a matter of milliseconds that resembles that of a real explosive event.
The on-campus setup allowed the team to refine their device before traveling to South Carolina for field explosives testing. In South Carolina the team worked with Keith Williams, a retired Navy SEAL, to conduct the explosives testing using weighted crash test dummies to simulate a soldier in the field. A number of orientations were used to allow the team to characterize the space and inform the device algorithms.
Back at RIT, additional testing was conducted in the Center for Integrated Manufacturing Studies' Environmental Chambers to see how the device withstands extreme heat, cold, and humidity. An acceleration shaker also helps to validate the gauge's ability to distinguish a pressure event from an acceleration event to avoid false positives.
The first-generation devices were provided to DARPA for field testing this April. Because it is such a complex problem significant data needs to be logged along with tracking soldier deficits over time to be able to correlate blast exposure with injury. "The more sensors that we are able to deploy, the stronger the data will be," explains Borkholder. Once enough information is gathered, a field medic will be able to use the device's data to determine what a soldier has been exposed to and assist with field triage.
In just 12 months the RIT team responded to this critical need by designing, engineering, testing, and providing first-generation units for testing. "This is a unique project for academia," Borkholder says. "It mirrors the rapid product development usually found in industry." There are very specific performance specifications and expected outcomes that were continually refined in close collaboration with DARPA program manager Jeff Rogers based on the latest research on traumatic brain injury, he explained. Borkholder's experience in industry and as an entrepreneur provided him with the know-how to deliver a complete system design product in an academic setting. "The laboratories and capabilities at RIT are truly unique for a university," adds Borkholder. "These facilities allowed us to respond quickly with a tangible solution for DARPA." This research has resulted in the formation of a company, BlackBox Biometrics™, which plans to commercialize the device in 2011.