Increase in cochlear implant electrode impedances with the use of electrical stimulation

• Published in: International journal of audiology 2020-10, Vol.59 (11), p.881-888
• Main Authors: Saoji, Aniket A., Adkins, Weston J., Olund, Amy P., Graham, Madison, Patel, Neil S., Neff, Brian A., Carlson, Matthew L., Driscoll, Colin L. W.
• Format: Article
• Language: English
• Subjects: cochlear implants; Electrode impedances; rising pattern
• ISSN: 1499-2027; 1708-8186
• DOI: 10.1080/14992027.2020.1799251

Electrode impedances play a critical role in cochlear implant programming. It has been previously shown that impedances rise during periods of non-use, such as the post-operative recovery period. Then when the device is activated and use is initiated, impedances fall and are typically stable. In this study, we report a new pattern where electrode impedances increase with device use and decrease with device rest. Electrode impedances were measured three to four times every day over a span of 1-3 months for two cochlear implant patients. Two patients with a Nucleus cochlear implant participated in this study. Both subjects in this study show wide fluctuations in electrode impedances. By taking serial electrode impedance measurements throughout a day of use, we observe that electrode impedances consistently increase with device use and decrease with device rest. In this study, we report two cases of electrode impedances increasing as a function of device use. Numerous management strategies were employed to reduce this effect but none prevailed; a clear pathophysiologic mechanism remains elusive. Further study into the cause of this electrode impedance pattern is warranted to establish a management strategy for these cochlear implant users.