Objective Measures to Characterize the Electrical Properties of the Electrode Array and the Surrounding Tissue

Angel Ramos de Miguel ¹ Angel Ramos-Macias ² Juan Carlos Falcón ² Timo Stoever ³ Goetz Brademann ⁴ Manuel Manrique ⁵ Ulrich Hoppe ⁶ Matthias Hey ⁴ Uwe Baumann ⁷ Alicia Huarte ⁸ Joachim Hornung ⁹ Riaan Rottier ¹⁰ Nicole Neben ¹¹

¹Acoustic and Balance Lab, Complejo Hospitalario Universitario Insular Materno-Infantil de Gran Canaria, Las Palmas de GC, Spain
²Otorhinolaryngology - Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno-Infantil de Gran Canaria, Las Palmas de GC, Spain
³Otorhinolaryngology - Head and Neck Surgery, Klinikum der J.W. Goethe-Universität, Frankfurt, Germany
⁴ENT Clinic, UKSH Kiel, Kiel, Germany
⁵Otorhinolaryngology - Head and Neck Surgery, Clinica Universidad de Navarra, Pamplona, Spain
⁶Audiology, Universitätsklinikum Erlangen, Erlangen, Germany
⁷Audiology, Klinikum der J.W. Goethe-Universität, Frankfurt, Germany
⁸Audiology, Head and Neck Surgery, Clinica Universidad de Navarra, Pamplona, Spain
⁹Otorhinolaryngology - Head and Neck Surgery, Head and Neck Surgery, Universitätsklinikum Erlangen, Erlangen, Germany
¹⁰Sound Processors and Clinical Care, Cochlear, Sydney, Australia
¹¹Clinical Studies, Cochlear, Hannover, Germany

Purpose of the study: The gold standard to verify the electrode position currently is through radiological imaging techniques, such as CT scan or X-ray. This imaging increases the cost and duration of the procedure and is linked with radiation which may put the patient at risk of ‘radiation-related’ disease. Therefore avoiding CT scans or X-ray is always beneficial for patients and enhances the advantage of a reliable objective measurement to characterize the electrical properties of the electrode array. This clinical investigation will gather objective measurements intra- and post-operatively to characterise the electrical properties of the electrode array in the cochlea after insertion.

Materials and Methods: A variety of different objective measures as NRT, impedance, trans-impedance and intra-cochlear voltage measurements and radiological imaging have been established for this multi-centric study at two centres in Spain and three in Germany for 154 Cochlear Nucleus® CI512 and CI532 cochlear implant recipients to be enrolled over a period of 15 months. The test battery is conducted intra-operative, during first activation and 3 months post-operative to explore the association between the trans-impedance and intra-cochlear voltage measurements, NRT thresholds and the radiological parameters.

Results: A statistically significant correlation between the objective measures and radiological parameters is hypothesized. Preliminary results will be presented at the conference.

Conclusion: The outcome presents sufficient evidence that objective measurements can be used to complement and potentially in future replace the radiological imaging techniques in cochlear implant surgery.