Stimulation Crosstalk Between Cochlear And Vestibular Spaces During Cochlear Electrical Stimulation

• Published in: The Laryngoscope 2024-05, Vol.134 (5), p.2349-2355
• Main Authors: Miguel, Ángel Ramos, Rodriguez Montesdeoca, Isaura, Falcón González, Juan Carlos, Borkoski Barreiro, Silvia, Zarowski, Andrzej, Sluydts, Morgana, Falcón Benitez, Nadia, Ramos Macias, Angel
• Format: Article
• Language: English
• Subjects: basic science; Case-Control Studies; Cochlea; Cochlear Implantation; Cochlear Implants; Electric Stimulation; Electrodes; Humans; Vestibular Evoked Myogenic Potentials - physiology; vestibular implant; Vestibule, Labyrinth
• ISSN: 0023-852X; 1531-4995
• DOI: 10.1002/lary.31174

Objectives Possible beneficial “crosstalk” during cochlear implant stimulation on otolith end organs has been hypothesized. The aim of this case–control study is to analyze the effect of electrical cochlear stimulation on the vestibule (otolith end‐organ), when using a cochleo‐vestibular implant, comparing vestibular stimulation (VI) and cochlear stimulation (CI). Methods Four patients with bilateral vestibulopathy were included. A double electrode array research implant was implanted in all cases. Dynamic Gait Index (DGI), VOR gain measured by using vestibular head impulse test (vHIT), acoustic cervical myogenic responses (cVEMP) recordings, and electrical cVEMP were used in all cases. Trans‐impedance Matrix (TIM) analysis was used to evaluate the current flow from the cochlea to the vestibule. Results While patients did not have any clinical vestibular improvement with the CI stimulation alone, gait metrics of the patients revealed improvement when the vestibular electrode was stimulated. The average improvement in the DGI was 38% when the vestibular implant was activated, returning to the normal range in all cases. Our findings suggest that any current flow from the cochlear space to the otolith organs was insufficient for effective cross‐stimulation. The functional results correlated with the data obtained in TIM analysis, confirming that there is no current flow from the cochlea to the vestibule. Conclusion The only way to produce effective electrical otolith end‐organ stimulation, demonstrated with this research implant, is by direct electrical stimulation of the otolith end organs. No effective cross‐stimulation was found from cochlear electrode stimulation. Level of Evidence 4 Laryngoscope, 134:2349–2355, 2024 We analyze in this research the possible beneficial “crosstalk” during cochlear implant stimulation on otolith end organs has been hypothesized. The aim of this study is to analyze the effect of electrical cochlear stimulation on the vestibule (otolith end organ), when using a cochleo‐vestibular implant.