Surface and subsurface electrodes for guiding stimulation electric currents with electric fields for cochlea implanted electrodes

Abstract

We disclose the use of passive, or field-shaping electrodes, below the surface of the supporting structure of a cochlear implant. The location of the field-shaping electrodes below the surface of the supporting structure, allows for the use of the field-shaping electrodes to exist in the structure without decreasing the available space for the active, stimulating electrodes at the surface. The field-shaping electrodes are to direct the electric currents injected by the stimulating (active) electrodes onto the one-and-only-one neuron that is expected, by the brain, to receive vibrations from one-and-only-one frequency. The objective of the field-shaping electrodes is to prevent, or, at least to decrease, the leaking of the stimulating current from any stimulating active electrode onto any neuron other than the neuron that is directly in front of the electrode in question, which is the only neuron that is expected to receive excitation for that frequency associated with each electrode.