Standard cochlear implants as intracochlear oxygen sensors

Abstract: The cochlear implant (CI) is the most famous neuroprotheses worldwide. By direct electrical stimulation of the auditory nerve it compensates hearing loss in patients. The platinum (Pt) electrodes of the CI are comparable to those of bio- and chemo-sensors. Using CI electrodes as sensors opens access to the microenvironment of the implant and the state of the electrode itself, promising novel insight into implant biocompatibility, function, and long-term stability.

We developed an electrochemical method to turn standard CI electrodes into electrochemical oxygen (O2) sensors. We used a chronoamperometric protocol, which cyclically renews the electrode surface to ensure signal stability and measures O2 via direct reduction at the Pt electrode. CI electrodes were used as working and counter electrodes, and a chloridated silver wire as reference electrode. Three CI electrodes (MED-EL) were inserted into the rats’ left cochlea while the reference electrode was placed in the middle ear.

In experiments in vivo, we demonstrated a stable baseline signal, indicating a well-oxygenated environment. Supplying rats with 100% O2 to the nose led to a fast and reproducible increase in intracochlear O2 levels and return to baseline. Stimulation via the same CI electrodes resulted in differentiated electrically evoked auditory brainstem responses indicating induced neuronal activity of the auditory system, not affected by previous electrochemical measurements.

We demonstrated that CI electrodes can be turned into chemical microsensors in vivo by using appropriate electrochemical methods. Besides the microenvironment, this can give access to electrode degradation using interspersed electrochemical methods and ultimately improve electrode stability and function by implant life-long monitoring

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Laryngo-Rhino-Otologie. - 101, S2 (2022) , S243-S244, ISSN: 1438-8685

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2022
• Creator: Roßkothen-Kuhl, Nicole ; Kieninger, Jochen ; Buchholz, Sarah ; Urban, Gerald A. ; Arndt, Susan ; Weltin, Andreas

Further information

• DOI: 10.1055/s-0042-1746797
• URN: urn:nbn:de:bsz:25-freidok-2319186
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:56 PM CET