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Development of gold wire-based electrodes for the direct round window stimulation for tinnitus suppression
Cochlear implant patients with tinnitus often provoke from the electrical stimulation of the auditory nerve and often the tinnitus was suppressed via electrical stimulation. Implant-based therapy has not yet been available for tinnitus patients with normal hearing. In our project (INTAKT), electrodes for direct round window stimulation were developed and evaluated electrophysiologically in an animal model using ABR measurement (auditory brainstem response). The round window electrode consisted of 2 thin gold wires in a silicone tube. The flat wire ends facing the round window served as the contact area (0.12 mm2). The silicone plate increased the geometric area to protect the round window membrane from punctual injury and improved the intraoperative fixation. The flexible wire allowed an individual adjustment in the middle ear. This electrode was successfully tested on an animal model and with regard to its implantation properties, the transmission of electrical signals to activate the auditory system in the monopolar (stimulation of a contact of the electrode on the round window against a counter-electrode placed outside the middle ear) and in the bipolar (stimulation of both contacts on the Round windows against each other) configuration are examined. The gold wire-based electrodes enabled stable and safe implantation and fixation in the middle ear. It was possible to successfully and reproducibly induce electrically evoked potentials of the auditory system at the round window and measure them using ABR. With bipolar stimulation, the activation of intracochlear neuronal structures was possible from a current strength of 1 mA, while monopolar stimulation required lower current strengths (approx. 200 μA).
das BMBF, Netzwerk INTAKT
13 May 2021 (online)
Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany