Speech understanding by cochlear-implant patients with different left- and right-ear electrode arrays.

Electrode-pitch rankings and monaural and binaural speech perception scores were obtained from two patients fit with a Med El CIS-Link processor and Ineraid electrode array in one ear and a Clarion processor and Hi-Focus electrode array in the other ear. The results of the electrode-ranking task indicated that current from the Hi-Focus electrodes extended more apically than current from the Ineraid array, i.e., the two most apical Hi-Focus electrodes were ranked lower in pitch than the most apical Ineraid electrode. Because of this and because of the different number of active electrodes in the two arrays, it is likely that the two cochleae presented different representations of the same signal to more central stages of information processing. In spite of this, both patients achieved better scores when both implants were activated than when the implants were activated one at a time.