Brain impedance measurements by the use of small bipolar needle electrodes.

Abstract

The use of small bipolar needle electrodes for the measurement of the capacitive properties of the brain tissue was found to be unsatisfactory. Electrode polarization effects, acting as a parasitaric phenomena, are the main obstacle of this method; thus, the values of capacitance obtained do not represent the capacitive properties of the tissue. In order to overcome the above difficulties, a comparison method was employed by which the electrical parameters measured in brain tissue were compared with the values obtained from an electrolyte solution of the same resistance.