Vestibular Function in Children and Adults Before and After Unilateral or Sequential Bilateral Cochlear Implantation

Abstract

Background: Cochlear implantation (CI) helps patients with severe or profound sensorineural hearing loss (SNHL) restore hearing and speech abilities. However, some patients exhibit abnormal vestibular functions with symptoms such as dizziness or balance disorders, after CI. Whether age at CI and CI approach (unilateral or sequential bilateral) affect vestibular functions in users with cochlear implants remains unclear.Objectives: To investigate the vestibular functions in children and adults before and after unilateral or sequential bilateral CI.Materials and Methods: Thirty-seven patients with severe or profound SNHL who were candidates for a first- or second-side CI were divided into three groups: first-side CI-implanted adults (≥18 years), first-side CI-implanted children (6–17 years), and second-side CI-implanted children (6–17 years). All cases were implanted with the round window approach to minimize damage to the intra-cochlear structures. The caloric test, vestibular evoked myogenic potential (VEMP) test, video head impulse test (vHIT), Dizziness Handicap Inventory (DHI), Pediatric Vestibular Symptom Questionnaire (PVSQ), and audiometric tests were performed before and 1 month after CI.Results: The abnormal rates of caloric test and VEMP test after CI in the first-side CI-implanted adults and children significantly increased compared with those before CI. The pre-implantation VEMP test showed significantly higher abnormal rates between first- and second-side CI-implanted children. No other significant differences of abnormal rates between first- and second-side CI-implanted children or between first-side CI-implanted adults and children were found. In second-side CI-implanted children, PVSQ scores significantly increased at day 3 post-implantation but decreased at day 30.Conclusion: CI has a negative effect on the results of caloric and VEMP tests, but not on vHIT, indicating that the otolith and low-frequency semicircular canal (SCC) are more vulnerable to damage from CI. The alterations of vestibular functions resulting from CI surgery may be independent of age at CI and CI approach (unilateral or sequential bilateral). Long-term impacts on the vestibular function from CI surgery, as well as the chronic electrical stimulation to the cochlea, are still to be investigated.

Effect of cochlear implantation on vestibular function in children: A scoping review

“…The caloric test was performed in seven of the included studies ( 9 , 27 – 32 ). Five of the seven articles determined that the caloric test was not significantly altered after implantation.…”

“…Three studies assessed the effect of cochlear implantation on canal function by (v)HIT ( 28 , 30 , 32 ). A consistent finding was that the (v)HIT was not affected by implantation per tested group ( Table 4 ).…”

“…Literature selection procedure. Included studies Jacot et al ( 9 ), Licameli et al ( 17 ), Dhondt et al ( 27 ), Ajalloueyan et al ( 28 ), Devroede et al ( 29 ), Thierry et al ( 30 ), Gupta and Raj ( 31 ), Guan et al ( 32 ), Imai et al ( 33 ), Li and Gong ( 34 ), De Kegel et al ( 35 ), Xu et al ( 36 ), Psillas et al ( 37 ), and Jin et al ( 38 ).…”

Vestibular function in children with cochlear implant: Impact and evaluation

“…There were no significant variations in DHI and PVSQ ratings between adults and children pre-and post-implantation for unilateral CI, according to the vertigo questionnaire ( 32 ). PVSQ scores in children with bilateral CI were significantly higher on day 3 after implantation but significantly lower on day 30, indicating that these changes could be due to initial postoperative response to anesthesia or a middle/inner ear injury ( 32 ).…”

“…As the use of bilateral implants grows, it will be critical to understanding the effects of bilateral CI surgery on the vestibular system, which will be beneficial to both the CI team and the patient. Guan et al ( 32 ) believes no remarkable differences in the abnormality rate between children with first- and second-sided CI implantation 1 month after CI, demonstrating that the effects of unilateral and bilateral sequential CI on vestibular function are similar. The VEMP, on the other hand, revealed that children implanted with a second-side CI had a higher rate of anomalies than children implanted with a first-side CI.…”