Aim: Postoperative vertigo is a well-known complication after cochlear implantation. The aim of the study was to investigate whether the electrical stimulation of the auditory structures via cochlear implant electrodes can affect the vestibular system and induce vertigo.
Materials and methods: In the first group, 114 patients were surveyed retrospectively via questionnaires to evaluate the occurrence and frequency of sound-induced vertigo after cochlear implantation. In the second group of 26 patients, the effects of electrical stimulation on the vestibular system were studied prospectively.
Results: In the first group of patients without any preoperative sound-induced vertigo (n = 104), 20 patients (18%) reported sound-induced vertigo, which occurred after cochlear implantation. In the second group, an acoustic stimulus delivered via the speech processor of the cochlear implant elicited a vestibular evoked myogenic potential response in 4 of the 26 patients as a sign of vestibular costimulation (of the macula sacculi as part of the otolith organs). Horizontal and vertical nystagmus was triggered, whereas utricular function and postural stability remained unchanged. No correlation was found between C/M levels and the vestibular evoked myogenic potentials and nystagmus responses.
Conclusion: Sound-induced vertigo can occur in cochlear implantees. This seems to be primarily caused by electrical costimulation of the sacculus as part of the otolith organs.