Prevalence of Endolymphatic Hydrops in Cochlear Implant Candidates with Idiopathic Profound Sensorineural Hearing Loss

Abstract

ObjectiveTo determine the prevalence of endolymphatic hydrops (EH) in cochlear implant (CI) candidates with idiopathic profound sensorineural hearing loss (SNHL) and its influence on the preservation of audiovestibular function after cochlear implantation.Study DesignProspective case series.SettingTertiary referral center.PatientsCI candidates with idiopathic progressive SNHL, but without classic EH-associated symptoms.InterventionsDelayed intravenous gadolinium-enhanced inner ear fluid-attenuated inversion recovery magnetic resonance imaging as well as pure-tone audiograms, video head impulse tests, and vestibular evoked myogenic potentials before and 4 weeks after cochlear implantation.Main Outcome MeasuresPrevalence of EH before cochlear implantation, audiovestibular function before and after surgery in hydropic and nonhydropic ears.ResultsThirty-two ears in 16 CI candidates were included. Nine ears (28%) with EH were detected. Although preoperative hearing thresholds, utricular function, and semicircular canal function were not different between the two groups, saccular function was reduced in hydropic ears. Ten subjects received a unilateral CI. Of these, 3 (30%) showed EH on the implanted side. There was no difference regarding postoperative hearing loss between the two groups, but the results point toward a higher vulnerability of hydropic ears with respect to loss of otolith function after cochlear implantation.ConclusionsThis is the first study showing that EH can be assumed in about one third of CI candidates with idiopathic profound SNHL, but no classic EH-associated symptoms. Preliminary results suggest that EH has no influence on the preservation of cochlear function but could be a risk factor for loss of otolith function after cochlear implantation.

Post Cochlear Implantation Vertigo: Ictal Nystagmus and Audiovestibular Test Characteristics

“…SEH after CI (due to fibrosis and trauma) has been commonly reported in histological studies of human CI recipients, with prevalence rates ranging from 41 to 58% in line with our current findings (10,27). However, recent studies in implanted guinea pig cochlea reveal that EH is prevalent in the first weeks after surgery even in the absence of significant electrode trauma (28). Furthermore, a recent study by Mosimann et al (28) revealed that EH was found in 28% of CI candidates with idiopathic profound SNHL, but with no other EH-associated symptoms.…”

“…However, recent studies in implanted guinea pig cochlea reveal that EH is prevalent in the first weeks after surgery even in the absence of significant electrode trauma (28). Furthermore, a recent study by Mosimann et al (28) revealed that EH was found in 28% of CI candidates with idiopathic profound SNHL, but with no other EH-associated symptoms. In our group, the cause of hearing loss for these patients included adult-onset progressive hearing loss, congenital/childhood-onset hearing loss, SSNHL, and other causes.…”

“…Pre-CI data were often lacking, which would have enabled better interpretation of postoperative abnormalities. The finding that EH can be radiologically evident but clinically undetected in CI candidates with SNHL (28) draws attention to the need for pre-CI screening; the caloric test especially could have provided valuable baseline information on the likelihood of hydrops, given its high abnormality rate when compared with the vHIT in hydropic patients (37). Large prospective studies with presurgical and postsurgical vestibular screening are likely to help clinicians determine which tests contribute most to the differential diagnosis of post-CI vertigo.…”

Cochlea-Implantation

“…Es wird deshalb eine Assoziation zum Auftreten eines endolymphatischen Hydrops nach der Implantation angenommen [18]. Die Inzidenz eines endolymphatischen Hydrops nach CI wird mit 59 % angegeben [19], während sie vor der Implantation bei nur etwa 28 % liegt [20].…”