Can intracochlear voltage matrix analysis explain the occurrence of electrically evoked vestibular responses in cochlear implant users?

Authors

Ahmed Salha, Luise Wagner, Sebastian Strieth, Klaus W G Eichhorn, Laura Fröhlich

Published in

Zeitschrift fur medizinische Physik. Jul 04, 2026. Epub Jul 04, 2026.

Abstract

This study examined how intracochlear voltage distributions obtained from impedance field telemetry (IFT) in cochlear implant (CI) users with straight lateral wall electrodes related to electrically evoked cervical and ocular vestibular myogenic responses (e-cVEMPs and e-oVEMPs).
e-cVEMPs and e-oVEMPs were recorded in adult MED-EL Synchrony CI users by stimulating at intracochlear electrodes E3, E6, E10 and E11. IFT provided voltage matrices characterizing intracochlear electric field distribution. Voltage data were adjusted using a current-dependent scaling factor to account for stimulation-level differences, and both qualitative and quantitative analyses were performed to compare participants with and without e-VEMP responses and to assess spatial dependencies between voltage profiles and vestibular activation.
The study included 18 implanted ears of 17 participants. Qualitative evaluation of the difference matrices across all stimulation electrodes revealed local variations within individual stimulation sites, but no consistent group-specific pattern that persisted across electrodes for either e-cVEMPs or e-oVEMPs. Quantitative analysis of voltage line graphs showed higher voltages and e-oVEMP thresholds across all sites in participants with e-oVEMPs, reaching significance only at E3. For e-cVEMPs, analysis showed no significant group differences. Detection rates demonstrated a spatial trend, with e-cVEMPs occurring predominantly during basal stimulation and e-oVEMPs during apical stimulation.
These data suggest that there could be different current pathways for saccular and utricular co-stimulation. Intracochlear electric field distributions could not be directly correlated with e-VEMP occurrence. Spatial dependencies and voltage decay patterns suggest separate mechanisms, possibly related to differences in local field orientation and tissue conductivity, which have to be further examined with respect to anatomical data.

PMID:
42401534
Bibliographic data and abstract were imported from PubMed on 05 Jul 2026.

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