Researchers show how lateral head injury could damage the brain and cause a concussion

Practice contact sports for an indefinite period of time and at some point you will probably ring the bell with a loud blow to the head caused by a fall or violent shock. The growing awareness of the serious and persistent impact of violent head impacts – concussions, mild traumatic brain injury, neurological disorders – has led scientists to focus on what exactly happens inside the skull when a shock.

Mehmet Kurt, a mechanical engineer at the Stevens Institute of Technology, who studies the biomechanics of the brain and skull at rest and during rapid movements of the head, has now conducted bioengineering simulations that badyze the brain behavior during an impact, restoring the predominant stresses and tensions of inertia. in a brain that has just been hit hard.

"The brain is not only ringing, but it has a distinct pattern of ringing when the head is hit from the side and is undergoing a rotating acceleration," said Kurt, whose work might have implications not only for the badessment of brain injuries, but also for sports helmet manufacturers looking for measurable parameters that simply distinguish "concussion" from "no concussion" to help the industry set safety standards. The document appears in the July 30 issue of Applied physical examination.

By badyzing a combination of simulated and human brain movement data that has led to concussions, Kurt and his group, including Stevens' graduate student, Javid Abderezaei, reveal numerically that side impacts on the head result in accelerations of rotation that cause the concentration of mechanical vibrations brain regions: the corpus collosum, the bridge that connects the hemispheres and the periventricular region, from white matter lobes to the root of the brain that help to accelerate muscle activation.

Kurt and Abderezaei, along with Kaveh Laksari of the University of Arizona and Songbai Ji of the Polytechnic Institute of Worcester, found that the internal geometry of the skull and the gelatinous nature of the brain bring about the resonance of these two regions at certain frequencies and receive more mechanical energy in the form of shear forces than the rest of the brain. Higher shear stress probably produces more damage to tissues and cells, particularly because opposite shear movements tend to deform brain tissue more easily than other biological tissues.

"A blow to the head creates a non-linear motion in the brain," said Abderezaei. "This means that small increases in amplitude can lead to unexpected large deformations in some structures."

These non-linear vibrations are not surprising in a complex organ with a range of tissue densities. Add to that the protective effects of tough protective membranes, especially those of falx and tentorium, which keep the brain in place from both above and below, and some regions are inevitably more affected by lateral shocks.

Identifying which parts of the brain are most exposed to side impacts makes it a prime target for further research to better understand concussions and better understand brain behavior in collisions. Such knowledge does not come soon enough. More than 300,000 American children and teenagers experience sport-related concussions every year.

In 2018, Kurt and his colleagues won a Vizzies Choice Award for a video showing how the brain moves at rest with each heartbeat.