Researchers at Sandia National Laboratories and the University of New Mexico (UNM) are comparing supercomputer simulations of blast waves on the brain along with clinical studies of veterans suffering from mild Traumatic Brain Injuries (TBI) to help improve helmet designs.
Paul Taylor and John Ludwigsen at Sandia’s Terminal Ballistics Technology Department and Corey Ford, a neurologist at UNM’s Health Sciences Center are in the final year of a four year study researching mild TBI funded by the Office of Naval Research.
The team hopes to identify threshold levels of stress and energy so that better military and sports helmets can be designed. It is thought that sensors could be placed on helmets to show whether a blast is strong enough to cause TBI and alert the patient and their doctor if there is a potential problem.
The Sandia and UNM study is the only TBI research being conducted that combines computer modeling and simulation of the physical effects of a blast along with studying the clinical magnetic resonance images of patients suffering these injuries.
Immediately following blast waves, soldiers can suffer brief losses of consciousness but more symptoms can be apparent weeks later such as headaches, memory loss, mood disorders, depression, and cognitive problems. The researchers are applying shock wave physics to understand how sensitive brain tissue is affected by waves from roadside bombs or blunt impacts within the first 5-10 milliseconds.
The researchers imported digitally processed computed tomography scans of various helmet designs into the simulations to assess the protective merits of each helmet against blast loading. The 3-D simulations are visualized using two-dimensional multi-colored images of a man’s head that has recorded an enormous amount of data. The focus is on studying the three types of energy entering the brain that may cause TBI. The pressure and stress within the brain show up as colors moving in slow motion through and around the brain cavity on videos created from the simulations.
The research showed that certain regions of patients’ brains are hyperactive perhaps because they are compensating for adjacent damaged areas of the brain that were hit with high energy from the blasts. The hyperactive regions are those that experience the least shear and tensile energies, according to the computer simulation which can predict where the hyperactivity will likely occur.
Once the researchers are able to determine exactly how and where the wave energy deposited in the brain gives rise to injuries, they will be able to provide thresholds of stress and energy levels that cause TBI.
On the clinical side a battery of tests were used in patients enrolled in the study to measure the subject’s memory, language, and intelligence. These results were correlated with changes in functional magnetic resonance imaging (fMRI) from the patients. The 3-D fMRI studies were able to detect and map networks in the brain used for processes like movement, vision, and attention.
By comparing this data with data from a control group, the researchers were able to identify a subgroup of networks displaying abnormal brain activity in the patients. These results were then compared with energy deposition maps predicted by the computer simulations.