Intracranial pressure instability: analysis with a simple mathematical model

A simple mathematical model of intracranial pressure (ICP) dynamics is presented. It incorporates the main factors which are known to affect ICP in the short period, i.e., the cerebrospinal fluid (CSF) circulation, the nonlinear craniospinal compliance and the active cerebral blood volume changes induced by autoregulation. The model is used to study the stability of ICP dynamics in pathological conditions. Analysis of model eigenvalues and of bifurcation diagrams reveals that intracranial dynamics becomes unstable in pathological conditions characterized by a decrease in craniospinal compliance and a decrease in CSF outflow. Computer simulations show that the lose of stability manifests itself through a paradoxical ICP response to small initial perturbations and, in the more severe cases, with large-amplitude self sustained waves (plateau waves). All the previous results agree with those reported in the clinical literature