Diffuse Axonal Injury and Degradation in Mechanical Characteristics of Brain White Matter

Diffuse Axonal Injury (DAI) can happen due to sudden motions of head and is one of the major causes of fatality and severe disabilities. To study DAI, any change in material characteristics of brain tissue post injury needs to be well understood. In this study, the focus will be on changes in the viscoelastic material properties of white mater in the brain due to DAI resulting in axonal disconnections. Using a micromechanics fibrous composite modeling for white mater, we have developed an algorithm to analyze the effect of discontinuity due to breakage of axons inside the surrounded matrix. Repeated unit cell (RUC) was assumed to represent the axonal distribution within the extracellular matrix. Relaxation test were conducted for characterization of the viscoelastic behavior. The result of this study provides a modeling technique for characterization of injured brain tissue in white mater and proposes necessity of including the appropriate post injury axonal mechanical properties. These findings can improve the understanding of injury from mechanical perspective and help in predicting vulnerability of any such injured tissue against further injuries.