Predictors of Postoperative Electrode Deactivation Among Adult Cochlear Implantees

To characterize postoperative electrode functionality after adult cochlear implantation; to identify rationale and risk factors for electrode deactivation.

Retrospective Chart Review.

Academic Cochlear Implant Center.

Five hundred nineteen cochlear implants in 433 adult patients over 5 years.

Unilateral or bilateral cochlear implantation.

Rate of electrode deactivation after adult cochlear implantation.

One hundred twenty (27.7%) patients experienced electrode deactivation postoperatively, involving a total of 447 electrodes. The most common reasons for deactivation were bothersome nonauditory symptoms (n = 170, 38.0%), perceived benefit by patients (n = 64, 14.3%), and bothersome auditory symptoms (n = 60, 13.4%). Four hundred nineteen (93.7%) of involved electrodes remained deactivated at most recent follow-up, whereas 28 (6.3%) were able to be reactivated. Deactivation was most likely to occur within the first 4 weeks after activation (n = 90 patients,75.0%; p < 0.01). Among affected patients, the average number of electrodes deactivated was 3.44 (range 1-13; SD 2.50). Age was not associated with electrode deactivation.

While 98% of cochlear implants had full insertions, more than a quarter of implantees may experience electrode deactivation postoperatively for a multitude of reasons, with bothersome nonauditory symptoms most prevalent. Deactivation of five or more electrodes and simultaneous deactivation of two or three electrodes seems to increase the odds of subsequent device failure. However, deactivation encompasses a wide range of issues that likely include patient factors, surgical technique, and device-specific issues. Prognosis varies greatly at the individual level and further evaluation is required to better identify the issues underlying deactivation and identify true predictors of failure.