Retrospective Study Comparing Audiologic Performance and Surgeon Learning Curve between Cochlear Implant Devices

Abstract

Objectives: 1) Describe the challenges of using a new cochlear implant (CI) manufacturer in a well-established CI program. 2) Recognize that a learning curve exists for all surgeons and audiologists using new CIs. Methods: A retrospective study was performed in a tertiary care center involving 25 consecutive CIs placed in post-lingually deafened adults from January 2009 to September 2012. Audiological evaluations were compared at 3-4 month and 12-month follow-up visits. Patients were divided into two groups: patients implanted using a new manufacturer to the institution (Med-El, M group, n = 13) and patients implanted using an established manufacturer (Cochlear, C group, n = 12). Multiple linear regression analyses models used soundfield detection, Consonant Nucleus Consonant (CNC), and Hearing In Noise Test HINT) while adjusting for confounding factors (significance if P < 0.001). Results: A strong statistical correlation (r2 > 0.5) was observed among age at implantation, duration of deafness, pre-implant speech perception score, and device type and the outcome measures at 3-4 months and 1-year follow-up. However, none of them reached statistical significance ( P value > 0.001). The device type (Cochlear against Med-El) approached significance with SFD at 3-4 months and at 1-year follow-up ( P value = 0.003, 0.002 respectively). Conclusions: While the Cochlear system recipients initially seemed to perform better than the Med-El recipients, this difference disappeared as experience with the newer implant system progressed. Other variables are more important than device type. However, sources of variability such as surgical and audiological inexperience with a new CI system highlight challenges facing a CI center attempting to modify an existing CI program.