• Visual Abstract

Stimulation conditions leading to electrical vestibular co-stimulation in cochlear implant users

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  • Otologie / Neurootologie / Audiologie
    • Cochleaimplantat

Abstract

Introduction

In some CI users, electric current spread can lead to facial nerve or vestibular co-stimulation. The study objective was to investigate CI stimulation parameters for electrically elicited cervical and ocular vestibular-evoked myogenic potentials (e-cVEMPs and e-oVEMPs) in Nucleus and Synchrony CI users.

Methods

E-VEMPs were recorded using electric tone bursts consisting of 4 biphasic pulses at 1000 Hz burst rate. In Nucleus CI users, monopolar stimulation at electrode contacts E3 and E20 as well as bipolar transmodiolar stimulation between E3 and E14 was used and the electric tone burst was further varied with respect to the numbers of pulses and burst rate in patients with e-VEMP responses. In Synchrony CI users, monopolar stimulation at electrode contacts E10, E6, and E3 was used. E-VEMPs were analyzed with respect to response numbers, amplitudes, latencies, and thresholds.

Results

In Nucleus CI users, measurements were conducted in 30 ears of 27 participants. In total, e-VEMPs could be elicited in 13 ears (43%). Monopolar stimulation at E3 showed the highest response rate of 40%. The effect was clinically but not statistically significant. Stimulus variation did not affect response numbers. E-VEMP latencies were up to 3.1 ms shorter for electrical compared to acoustically elicited VEMPs. Some patients showed e-VEMP thresholds close to or below the electric hearing threshold level.

In Synchrony CI users, measurements are still ongoing and preliminary results will be presented.

Discussion

The occurrence of e-VEMPs is dependent on current path and likely to occur in CI patients with high stimulation levels and monopolar stimulation of basal electrode contacts. The effect of vestibular CI co-stimulation on balance has to be investigated in future studies.

Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.

Im Zusammenhang mit anderen Projekten erhielten die Autoren finanzielle Unterstützung durch Cochlear Ltd., Sydney, Australien und MEL-EL, Innsbruck, Österreich.