Engineers are taking a closer look at the brain’s “suspension system” and their insights could provide a way to limit or even prevent traumatic brain injury.
TBI can be devastating and debilitating. Despite intense interest and years of study, the exact mechanisms linking force and neurological injury remain unclear. Researchers know that the membranes separating the skull from the brain play a key role in absorbing shock and preventing damage caused during a head impact, but the details remain largely mysterious.
“The idea was to find out how protective are the layers of membranes that connect the brain to the skull,” says Philip Bayly, professor of mechanical engineering and chair of the mechanical engineering & materials science department at the School of Engineering & Applied Science at Washington University in St. Louis.
“They serve the same function as the suspension in your car. When you go over a bump in a car, there’s a big oscillation of the wheels but you get very little motion in your body because the suspension absorbs it.
“We know that the membranes are there to cushion the brain, but by how much, and what’s the variation from person to person?”
During the study, researchers used an imaging technique called magnetic resonance elastography, or MRE, on six volunteers. During MRE, a vibrating pillow introduces tiny skull vibrations, which sensors embedded in a mouthguard measure. The researchers then measured motion of the brain via magnetic resonance imaging. When compared to a gelatin model that showed significant force transfer, the six subjects’ skull-brain interface significantly delayed and weakened the transfer of motion from skull to brain.
“We’re putting numbers to it, quantifying how much protection is actually there,” Bayly says. “During our study, 90 percent of the motion to the brain was attenuated.”
The next steps: eliminating the need for the mouthguard-sensor system and developing a more streamlined MRE method, which could enable a larger study with many more subjects.
“This would allow us to examine factors such as age or gender as variables when it comes to traumatic brain injury, and see who might be more susceptible to such injuries,” Bayly says.
The Journal of Biomechanical Engineering has accepted the work for publication.
Financial support for the study came from the National Institutes of Health.