A Multicenter Comparison of 1-yr Functional Outcomes and Programming Differences Between the Advanced Bionics Mid-Scala and SlimJ Electrode Arrays.

OBJECTIVE: To determine if there is a difference in hearing outcomes or stimulation levels between Advanced Bionics straight and precurved arrays. STUDY DESIGN: Retrospective chart review across three implant centers. SETTING: Tertiary centers for cochlear and auditory brainstem implantation. PATIENTS: One hundred fifteen pediatric and 205 adult cochlear implants (CIs) were reviewed. All patients were implanted under the National Institute for Health and Care Excellence 2009 guidelines with a HiRes Ultra SlimJ or Mid-Scala electrode array. MAIN OUTCOME MEASURES: Hearing preservation after implantation, as well as CI-only listening scores for Bamford-Kowal-Bench sentences were compared 1 year after implantation. Stimulation levels for threshold and comfort levels were also compared 1 year after implantation. RESULTS: Hearing preservation was significantly better with the SlimJ compared with the Mid-Scala electrode array. Bamford-Kowal-Bench outcomes were not significantly different between the two arrays in any listening condition. Stimulation levels were not different between arrays but did vary across electrode contacts. At least one electrode was deactivated in 33% of implants but was more common for the SlimJ device. CONCLUSION: Modern straight and precurved arrays from Advanced Bionics did not differ in hearing performance or current requirements. Although hearing preservation was possible with both devices, the SlimJ array would still be the preferred electrode in cases where hearing preservation was a priority. Unfortunately, the SlimJ device was also prone to poor sound perception on basal electrodes. Further investigation is needed to determine if deactivated electrodes are associated with electrode position/migration, and if programming changes are needed to optimize the use of these high-frequency channels.

Management of Severe Facial Nerve Cross Stimulation by Cochlear Implant Replacement to Change Pulse Shape and Grounding Configuration: A Case-series.

OBJECTIVES: To investigate the combined effect of changing pulse shape and grounding configuration to manage facial nerve stimulation (FNS) in cochlear implant (CI) recipients. PATIENTS: Three adult CI recipients with severe FNS were offered a replacement implant when standard stimulation strategies and programming adjustments did not resolve symptoms. Our hypothesis was that the facial nerve was less likely to be activated when using anodic pulses with "mixed-mode" intra-cochlear and extra-cochlear current return. INTERVENTION: All patients were reimplanted with an implant that uses a pseudo-monophasic anodic pulse shape, with mixed-mode grounding (stimulus mixed-mode anodic)-the Neuro Zti CI (Oticon Medical). This device also allows measurements of neural function and loudness with monopolar, symmetric biphasic pulses (stimulus MB), the clinical standard used by most CIs as a comparison. MAIN OUTCOME MEASURES: The combined effect of pulse shape and grounding configuration on FNS was monitored during surgery. Following CI activation, FNS symptoms and performance with the Neuro Zti implant were compared with outcomes before reimplantation. RESULTS: FNS could only be recorded using stimulus MB for all patients. In clinical use, all patients reported reduced FNS and showed an improvement in Bamford-Kowal-Bench sentences recognition compared with immediately before reimplantation. Bamford-Kowal-Bench scores with a male speaker were lower compared with measurements taken before the onset of severe FNS for patients 1 and 2. CONCLUSIONS: In patients where CI auditory performance was severely limited by FNS, charge-balanced pseudo-monophasic stimulation mode with a mixed-mode grounding configuration limited FNS and improved loudness percept compared with standard biphasic stimulation with monopolar grounding.