Abstract: A system for in-vivo monitoring of intracranial pressure is provided. The system includes a probe and a controller. The probe includes optical emitters and optical detectors. The optical detectors detect light emitted by the optical emitters generate signals representative of the detected light. The controller includes memory and processor. The controller connects to the probe to energize the optical emitters and receiving signals from the optical detectors. The system may include modelling, extraction, and pressure prediction modules. The modelling module can relate intracranial pressure to features of an optical signal representative of a degree to which light input into a subject's skull is absorbed by the subject's brain. The extraction module can extract signal features from a signal derived from the optical signals output by the detectors. The pressure prediction module can input the signal features into the modelling module and output an indication of intracranial pressure.