The shape of electrical impedance spectroscopy (EIS) is altered in stroke patients.

The shape of the Power Spectral Density Function (PSD) of the Electrical Field Distribution exhibit abnormalities in the brain structure when comparing chronic stroke patients with healthy volunteers. We built a System that can deliver White Noise currents in the 0-25kHz band to any electrode pair. The System is also capable of measuring potentials with a high-dynamic range (24 Bits) from eight pairs of shielded electrodes placed on the subject's head and lying on an axial plane approximately 3 cm above inion. In the stroke patients, the asymmetry in the CSF distribution in the brain modifies the spatial components of the scalp potentials with respect to healthy volunteers.