ECAP Thresholds in Children Implanted with Nucleus Slim Modiolar Electrode and Their Clinical Implications

Background

Electrically evoked compound action potentials (ECAPs) are routinely used clinically to assist fitting of cochlear implants, especially on recipients who cannot provide objective feedback. ECAP thresholds are typically used for shaping MAPs and as a guide to adjust overall loudness. Cochlear latest implant Nucleus CI532 uses a Slim Modiolar (SM) electrode, which is a different design compared to the Contour Advance (CA) electrode that has been used for many years.

Objective

The aim of this study was to assess ECAP thresholds in children implanted with a SM electrode (CI532), compare them to implantees with a CA electrode (CI512), and investigate whether potential differences have clinical implications.

Methods

Subjects up to 6 years of age with no inner ear malformation were included in the study. ECAPs were measured on 52 ears implanted with CI532. Data was collected during surgery and at least 6 weeks after activation. Thresholds were compared with similar data from patients implanted with Nucleus CI512.

Results

Preliminary results showed that ECAP thresholds for CI532 have a different shape compared to CI512. ECAP thresholds tend to be lower for apical electrodes and higher for basal electrodes. Statistical analysis for the whole data set will be presented at the conference. Clinical implications will be discussed.

Conclusion

ECAP thresholds for CI532 implants with SM electrode tend to be different from implants with CA electrode. CI audiologists should be aware this difference, especially if they have been used to work with the latter type of implants.