Session: 05-11-01: Musculoskeletal and Sports Biomechanics I

Paper Number: 69054

Start Time: Friday, 01:25 PM

69054 - Effect of Shaking at or Near Resonance of a Simple Head Model on Skull/Brain Connectors 

Shaken Baby Syndrome (SBS) is a well-recognized issue; however, there is still a significant debate about the actual mechanism that can produce this phenomenon from Duhaime et al. (1987), to Cory and Jones (2003), and onto Vester et al. (2019). Several studies have been performed that show the accelerations that can be produced by an average adult could or might not lead to the physiology associated with SBS. However, most of the work that has studied the biomechanics of SBS have focused on the accelerations experienced by the brain. However, more recently, the work of Laksari et al. (2019) has examined the role that resonance plays in brain injury by using a model that views the brain as a mass rotating about a point to which it was connected via a spring.

The present work complements Laksari’s work by examining the relationship between the resonant oscillations of the brain within the skull and the displacements induced within the structures that connect the pia mater to the arachnoid for different input acceleration profiles. To achieve this a simple three-dimensional model was created that consisted of a spherical brain within a hollow spherical skull, where the trabeculae and blood vessels were modeled as springs of different stiffnesses. The springs were placed uniformly within the subarachnoid space, and the brain was allowed to move freely. The skull was rigidly connected to a neck, which in turn was then connected to the body via a hinge joint with a torsional spring and damper.

This model was created to determine the extensions that the trabeculae and blood vessels would experience if the brain were to be excited close to its natural frequency, with the intent of exploring the possibility that the blood vessels spanning the subarachnoid space (SAS) could rupture because they “snag on or be entangled with … arachnoid trabeculae causing smaller gage lengths that require less displacement to rupture” as posited by Pasquesi et al. (2020). In addition, the issue of input profile was examined to study the affect that non-uniform accelerations might have on the displacements experienced by the trabeculae and blood vessels, as was done by Saboori and Walker (2019) with regard to impact loads.

The head motion was achieved by applying various types of input as prismatic motions applied to the body. For the initial runs, the input motion was a simple sinusoidal displacement, but other cyclical motions, such as a square wave, were also studied along with input motions that were obtained when a 12-month-old CRABI baby dummy was shaken. This was done to observe the manner and extent of the spring extensions at the different locations around the brain.

The results indicated that the maximum spring (“trabeculae”) extension was a function of the spring location around the head such that maximum extensions were associated with positions that experience both significant translational and rotational motions. The type of input also have a small impact on the maximum spring extension observed.

Presenting Author: Jose Daboin Manhattan College

Authors:

Jose Daboin Manhattan College
Parisa Saboori Manhattan College