Dr. Corey Ford can tell you that there are multitudes of damaging acoustic waves that very efficiently rocket through and within the skull in the first two milliseconds following an explosive blast. These initial waves and ripples – perhaps 20 or more – that occur well short of a single second following a blast likely exact some of the intracranial damage from a nearby exploding device. More interesting is how he knows this.
An HSC researcher in the Department of Neurology, Ford has assembled a high-performance team of specialists to model and probe the mechanisms of Traumatic Brain Injury (TBI). The team includes his operational UNM cadre, modeling experts at Sandia National Laboratories, leadership from the Veterans Administration, physicists and imaging analysis experts from the Mind Research Network and others.
The U.S. Department of Defense Office for Naval Research is providing $335,000 per year for three years to better understand the physics of explosive blast waves and TBI. Ford’s team has created several simulation models to measure the waves rattling the skull in the initial milliseconds following a blast.
Creating Models and Simulating Blasts
A blast-simulating computer model has been developed with Sandia National Laboratories physicist and mathematician Paul Taylor. Simulations of direct blast exposure to the head are conducted from the front, rear and profile. The high-fidelity model incorporates with great precision blast force, blast angle, human skull geometry and other pertinent variables.
A meticulous reconstruction of the human head serves as a model within the model. The Visible Human Project at the National Library of Medicine was tapped to acquire detailed frozen-section photos, as well as CT and MRI scans. All major anatomic regions of the brain are included – white and gray matter, cerebral spinal fluid, etc. – encased in a skull with anatomic air spaces wrapped in a scalp with muscle, tissue and bone, to accurately reproduce the human head and the effects of a nearby explosion.
Ford sees TBI research as truly translational, and wants results in the field as soon as possible.
"Because we’ve improved combat body armor and trauma medicine in the field over the years, we’re saving more lives in combat," Ford asserts. "We’re seeing more TBI. Several thousand U.S. soldiers have sustained TBI over the past decade – up to 70 percent as a result of blasts from sources like improvised explosive devices."
Beyond combat environments, TBI is a major public health problem with more cases annually than Alzheimer’s disease. Yearly incidence of TBI in U.S. is estimated at 1.4 million people, including 50,000 deaths and 235,000 hospitalizations. Naturally, young male adults are the most susceptible.
"Enormous levels of pressure, volumetric tension, and shear stress can occur in concentrated areas of the brain, dependent on the blast wave orientation and the complex geometry of the skull, brain and tissue," Ford adds. "I expect our model to contribute to understanding the mechanisms of TBI. With that data, we can provide a life-saving toolkit for providers of protective devices.