The model correctly predicted the CSF pressures noted in vivo, suggesting that high arterial inflow is required for patients with low-grade stenoses to be symptomatic.

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Idiopathic intracranial hypertension (IIH) is a syndrome of unknown etiology characterized by elevated intracranial pressure (ICP). Although a stenosis of the transverse sinus has been observed in many IIH patients, the role this feature plays in IIH is in dispute. In this paper, a lumped-parameter model is developed for the purpose of analytically investigating the elevated pressures associated with IIH and a collapsible transverse sinus. This analysis yields practical predictions regarding the degree of elevated ICPs and the effectiveness of various treatment methods. Results suggest that IIH may be caused by a sufficiently collapsible transverse sinus, but it is also possible that a stenosed sinus may persist following resolution of significant intracranial hypertension.

The experimentally-measured pressure-volume relationship for the human intracranial system is a nonlinear`S-shaped'curve with two pressure plateaus, a point of inflection, and a vertical asymptote at high pressures where all capacity for volume compensation is lost. In lumped-parameter mathematical models of the intracranial system, local compliance parameters relate volume adjustments to dynamic changes in pressure differences between adjacent model subunits. This work explores the relationship between the forms used for local model compliances and the calculated global pressure-volume relationship. It is shown that the experimentally-measured global relationship can be recovered using physiologically motivated expressions for the local compliances at the interfaces between the venouscerebrospinal fluid (CSF) subunits and arterial-CSF subunits in the model. Establishment of a consistent link between local model compliances and the physiological bulk pressurevolume relationship is essential if lumped-parameter models are to be capable of realistically predicting intracranial pressure dynamics.

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