1. A system, for determining an estimated intracranial pressure (ICP) of a first patient, comprising: a processing module that: receives a first input based on a first plurality of measurements of a first physiological parameter of the first patient, the first physiological parameter correlating with ICP; receives a second input based on a second plurality of measurements of a second physiological parameter of the first patient, the second physiological parameter correlating with ICP; processes the first and second inputs based on an ICP model; and outputs data indicative of the estimated ICP of the first patient; wherein the ICP model is chosen from a plurality of potential ICP models, each of the potential ICP models corresponding to a respective model patient, other than the first patient, and representing a transform function that transforms (a) time series information indicative of measurements of the first and second physiological parameters of the respective model patient to (b) time series information indicative of measurements of ICP of the respective model patient; wherein each of the plurality of models transforms (a) time series information indicative of measurements of the first and second physiological parameters of an index patient other than the respective model patient to (b) time series information indicative of an estimated ICP of the index patient, wherein a dissimilarity value indicates a dissimilarity between the index patient's estimated ICP and the index patient's observed ICP; wherein each of the potential ICP models has an associated mapping function that maps values of said first and second physiological parameters, of each patient in a group of patients other than the respective model patient, to at least one dissimilarity value corresponding to each of the patients in the group; wherein said ICP model is chosen based on dissimilarity values obtained by applying the mapping functions of each of the potential ICP models to data indicative of the first patient's first and second pluralities of measurements, to determine a dissimilarity value corresponding to each of the potential ICP models.