Design and fabrication of the banded electrode array

Abstract

A multiple-channel electrode array must meet certain design requirements; these are listed in TABLE 1. First, there should be no trauma associated with the surgical insertion, and if there is a need to replace the array, this procedure should also be atraumatic. Second, it should be biologically inert. This means that it should be biocompatible with the tissues. When placed in the cochlea, the array should also not predispose the patient to local infection, and this is particularly important in children, in whom recurrent middle ear infections could spread to the inner ear. There should also be no risk of carcinogenicity with long-term implantation. Third, the electrode array should be designed so that the stimulus current can be localized to discrete groups of nerve fibers, and it should also be possible to stimulate as many groups as possible from the total remaining nerve population. Fourth, with long-term stimulation, there should be no significant corrosion of the electrodes used, and the electrical stimulation should not lead to damage of the tissues in the cochlea, especially the residual nerve fibers. Fifth, the electrode array should be mechanically robust and stable. It should not be prone to break as a result of repeated stress by the acceleration of the head during everyday movements. The array should also be capable of being fixed in place so that it will not shift its position. Sixth, it is desirable that the means of fabrication of the multiple-channel array should be simple and inexpensive. (From Introduction)