The effects of cochlear implant electrode deactivation on speech perception and in predicting device failure

To examine speech perception outcomes as related to a reduction in the number of functional electrodes postimplantation and to determine the effect of electrode reduction on subsequent device failure. Retrospective review. Tertiary academic referral center. Of 1,520 children and adults with full insertions of the Advanced Bionics, Med El, and Nucleus devices, 15 (1%) were patients. Patients were included in the study if all electrodes were functional at initial stimulation, but the number of electrodes in use was subsequently reduced at follow-up programming sessions. Exclusion criteria included partial and split-array electrode insertions. Patients with bilateral severe to profound sensorineural hearing loss underwent either unilateral or bilateral cochlear implantation. Postimplantation speech perception tests obtained with a full complement of functional electrodes were performed and the results compared to those obtained with 1 or more electrodes removed from the user program. Electrode deactivation was also correlated with device failure. The results of this study indicate that deactivation of cochlear implant electrodes is relatively uncommon, and although the deactivation does not have a direct influence on speech performance outcomes, the loss of 5 or more electrodes can suggest impending device failure. Additionally, those patients with electrode deactivation coupled with a decline in speech perception scores should also be considered at risk for device failure.