Traumatic Brain Injury Research:

Traumatic brain injury (TBI) is the leading cause of death and long-term disability among US citizens age 45 and younger. We study TBI on three levels to determine cellular injury in response to shear strain (Level I), shear strain caused by head acceleration (Level II), and the effect of helmets on head acceleration during head impacts (Level III).

Level I: Cellular injury caused by shear strain.

We developed an organotypic model to study the effects of a defined mechanical insult on the biological injury cascade in brain. This model uses organotypic brain slices, which maintain the heterogeneous cell distribution and architecture of neuronal tissue in a controlled culture environment, while avoiding the systemic complexity inherent to in vivo TBI models. Our TBI model induces a defined mechanical injury by impact-induced acceleration of organotypic slices, which subjects the slices to inertia-driven shear strain. This injury mechanism correlates clinically to closed head injury, in which shear strain of brain can lead to diffuse axonal injury while the skull remains intact. At this point, we have characterized the organotypic TBI model, and have established cell-type specific dose-response curves.
This research is driven by neurological scientists Theresa Lusardi, Ph.D. and Zhi-Gang Xiong, MD, Ph.D, in collaboration with Mark Sommers, MS, and Michael Bottlang, Ph.D. of the Legacy Biomechanics Laboratory.
Funding Source: NINDS, R01 NS04294602

Level II: Shear strain caused by head acceleration.

Mark Sommers, MS, studies brain distortion in response to head acceleration on a life-scale head replicate. Specifically, he developed an experimental strategy to investigate the distinct effects of rotational and linear head acceleration on shear strain in brain. Understanding injury mechanisms which cause high shear strain in brain is key to optimize interventions for head protection.
Funding Source: Legacy Foundation

Level III: Effect of helmets on head acceleration.

Larry Ehmke, MS, and Mark Sommers, MS, established a helmet drop test system in compliance with the US standard for bicycle helmets. He advanced this test system to include simulation of more realistic impacts that occur at an angle to the ground. This advanced helmet testing facility provides the Legacy Biomechanics Laboratory with a unique resource for the evaluation and optimization of bicycle helmets.
Funding Source: Apex HPS, LLC