COMPARISON OF HALF-BAND AND FULL-BAND ELECTRODES FOR INTRACOCHLEAR ELECTRICAL-STIMULATION

It was hypothesized that intracochlear stimulating electrodes oriented toward the modiolus would require a lower stimulus current to elicit a threshold neural response than longitudinal band electrodes. Electri cally evoked auditory brain stem responses (EABRs) and electrode imped ances were recorded with full-band and oriented half-band scala tympan i electrodes in anesthetized, deafened cats. To elicit a threshold EAB R, the stimulus current required for stimulation through half-band ele ctrodes oriented toward the modiolus was not significantly different f rom the current required for stimulation through full-band electrodes. The impedances of full-band electrodes were significantly lower than those of half-band electrodes. Considering the significantly higher im pedance and current density of half-band electrodes in comparison to f ull-band electrodes, as well as the critical orientation of half-band electrodes during implantation, we believe that full-band electrodes h ave advantages over half-band electrodes for scala tympani implantatio n.