Clinical use of electrode differentiation to enhance programming of cochlear implants.

The effect of deactivating indiscriminable cochlear implant (CI) electrodes for unilaterally implanted adults was evaluated using the BKB (Bamford-Kowal-Bench) sentence test in quiet and in pink noise (signal-to-noise ratio of +10dBA) and the adaptive Coordinate Response Measure (CRM). Each CI recipient who failed electrode differentiation (ED) in at least one electrode-pair, based on results of a pure-tone pitch-ranking task received two research programmes to try out in a cross-over study. Research programmes (RP) either employed discriminable electrodes only or the most discriminable two-thirds of the electrodes in the electrode array for CI recipients failing ED for more than a third of the electrodes. The participants were also asked to subjectively report improvement of or decline in sound quality in everyday listening situations. There was significant improvement in CRM speech reception thresholds (SRTs) (Z = -3.24, N = 15, P = 0.001), BKB sentence scores in quiet (t = 3.17, df = 24, P < 0.005) and also in pink noise (t = 2.26, df = 19, P < 0.005) after deactivating indiscriminable electrodes.