Vestibular and taste disorders after bilateral cochlear implantation

Abstract

The objective of this study was to investigate the occurrence of vestibular receptor deficiency and taste disorders after bilateral cochlear implantation in postlingually deafened patients and to find out whether the risk for these complications is higher for the second implantation. In a retrospective cohort study, we examined 20 patients (11-58 years, mean age 41.5 years), implanted sequentially between 2000 and 2007 (mean period between cochlear implantation 32.9 ± 25 months). Pre- and postoperative vestibular testing was performed by subjective rating [Dizziness Handicap Inventory (DHI)], caloric irrigation [vestibuloocular reflex (VOR)] and by vestibular-evoked myogenic potential (VEMP) recordings for saccular function. The sense of taste was evaluated pre- and postoperatively by a questionnaire and testing (sour/sweet/bitter/salty bilaterally on the tongue). DHI evaluation showed a moderate not significant mean increase by 2.7 ± 7.7 SD points after the first and a significant increase by 9.4 ± 16.6 SD points after the second implantation. Ipsilateral VEMP responses disappeared in three ears (27.3%) after the first and in two ears (18.2%) after the second operation. VOR disappeared only once (5.9%) after the first implantation. One (5%) patient complained of a persisting disturbance of taste in the questionnaire after unilateral and 3 (15%) after bilateral implantation. Specific testing showed in one case (5%) a unilateral taste disorder after ipsilateral cochlear implantation. Our data show that there is a higher risk for subjective vertigo after the second implantation. The occurrence of unilateral and/or bilateral vestibular dysfunction and the potential risk of taste disorder should be included in the risk counseling before bilateral cochlear implantation to increase patients' and medicolegal safety in the decision-making process.

Association between Hearing Loss and Vestibular Disorders: A Review of the Interference of Hearing in the Balance

“…They found that specific testing showed in one case (5%) a unilateral taste disorder after ipsilateral cochlear and that there is a higher risk for subjective vertigo after the second implantation. To increase patients' and medico legal safety in the procedure, the occurrence of unilateral and/or bilateral vestibular dysfunction and the potential risk of taste disorder should be included in the risk counseling before bilateral CI [16].…”

Ocular and cervical vestibular-evoked myogenic potentials in children with cochlear implant

“…The data of oVEMPs after CI have not been reported yet. The rate of postoperative hypofunction was reported to be 13-86% in cVEMP (Todt et al, 2008;Krause et al, 2009;Licameli et al, 2009;Melvin et al, 2009;Krause et al, 2010;Wagner et al, 2010). Jin et al (2006)reported a response rate change in children with severe sensorineural hearing loss: seven of 12 patients presented normal cVEMPs before CI, but all disappeared after CI.…”

“…Adunka et al (2004) carried out a histological evaluation of electrode insertions, and they reported that smooth implantations via the round window membrane contributed to vestibular protection and successful insertion. Wagner et al (2010) reported that, with the modified RWA, only 22.7% (5/22) of patients exhibited hypofunction of cVEMP postoperatively, and the impact was relatively mild. The authors suggested that this could be related to surgical procedures, and they emphasized the benefit of the modified round window approach and its minor impact on the labyrinth.…”

Eye Movements in Response to Electrical Stimulation of the Lateral and Superior Ampullary Nerves

“…We prefer the first option as it may limit the risk of hearing loss due to the introduction of a foreign body in the perilymphatic space. This is illustrated by an increasing number of publications reporting deleterious effects of cochlear implantation on the vestibular function [18,19] (approximately 1 mm 2 ) may be a problem in the future. During an acute experiment, the electrode can be precisely maintained in place for a few minutes, manually.…”