Long-Term Cochlear Implant Sensitivity in Patients With Far Advanced Otosclerosis

Cochlear implantation in otosclerosis patients presents unique surgical and programming challenges. The success and satisfaction of these patients heavily depend on precise speech processor fitting. Increased bone growth and tissue mass associated with otosclerosis can hinder electrical current flow, adding resistance to stimuli transmission to ganglion cells. This study aimed to evaluate mid- and long-term cochlear implant fitting in otosclerosis patients compared to a control group.

This was a monocentric retrospective case-control study conducted at a tertiary referral center comparing patients with far advanced otosclerosis and a control group of post-lingually deafened individuals from the same database. Data collected included: age, sex, etiology, hearing deprivation duration, implantation age and side, surgical details, postoperative complications (e.g., tinnitus, dizziness, or facial nerve stimulation), hearing tests, and cochlear implant fitting details.

The study analyzed 80 patients: 29 with otosclerosis and 51 controls. Higher impedances were seen in the otosclerosis group at 2 and 5 years, statistically significant for basal, middle, and overall electrodes at 2 years. Higher C- and T-levels for apical electrodes at 2 years were identified, and neural response telemetry thresholds were significantly higher for medial and apical electrodes in otosclerosis patients at 2 years. Despite these differences, auditory outcomes at 5 years were comparable between groups.

These findings suggest significant tissue remodeling at the cochlear apex in otosclerosis patients, likely increasing resistance to electrical currents delivered by the implant. This highlights the importance of tailored programming and long-term monitoring for otosclerosis patients.

Level 3.