Wireless intracranial pressure monitoring through scalp at microwave frequencies; preliminary phantom and animal study

Clinical determination of intracranial pressure (ICP) is critical to the management of head injuries and diseases of the brain (e.g., Hydrocephalus), in order to avoid death and disability. The feasibility of acquiring intracranial pressure information through scalp at 2.4 GHz ISM band is demonstrated through in-vivo animal study. A previously fabricated device, including a piezoresistive sensor, an oscillator, and a chip antenna, irradiating a signal whose frequency depends on ICP, was implanted in pig skull. This experiment was primarily conducted for studying the biocompatibility of the device, signal transmission through scalp, and the frequency sensitivity of the device with ICP change. The possibility of pressure monitoring through scalp at 2.4 GHz ISM band was verified, as the received signal strength agreed with the in-vitro phantom experiment result, as expected. Moreover, a correlation between the ICP pressure and the irradiated frequency was demonstrated.