Brain Biomechanics: Consolidation Theory of Hydrocephalus. Variable Permeability and Transient Effects

The quasi-steady linear consolidation theory is applied to a model brain under hydrodynamic loading, due to a step increase of intracranial pressure, in order to gain insights into the onset and evolution of hydrocephalus and brain edema in children. Simple asymptotic formulas are derived that shed light on the transient behavior of the dynamics of filtration and of the deformation of the solid matrix, and it is shown that the results hold over time intervals much shorter than the consolidation time which is estimated to be of the order of several hours. Finally, the role of a variable permeability and of the complications introduced by it in the analysis of the transient response are discussed.