In Vivo Real-time Remote Cochlear Implant Capacitive Impedance Measurements: A Glimpse Into the Implanted Inner Ear

Abstract

OBJECTIVES: To propose a remote, real-time, safe, and easy systematic method to determine electrode electric impedance components: access resistance, polarization capacitance, and polarization resistance. PATIENTS: Patients who received a cochlear implant and had normal cochlear anatomy and complete array insertion were recruited. A total of four adult patients were included and separated in two groups according to implantation time. INTERVENTION: Cochlear implant electrical impedance and its components were measured in all patients by using a novel diagnostic tool: a custom made software running in the patient's computer. Data is transmitted in real time to the investigator. Various stimulation and measuring strategies were used to obtain specific information in each cochlear region. MAIN OUTCOME MEASURES: Access resistance, polarization capacitance, and resistance of each patient were measured. Measurement success rate and required time for the patient were recorded. RESULTS: Access resistance, polarization capacitance, and resistance were obtained in different modes, thus in every specific region of the cochlea. All measurements were successful. Each measurement took approximately 7 minutes and was transmitted in real time to the investigators. CONCLUSION: Routine use of this tool may allow constant assessment of cochlear health and could be eventually used to monitor the effect of drugs in the inner ear. This methodology provides an in vivo "electrical view" of the inside of the implanted cochlea.