Vestibular function after simultaneous bilateral cochlear implantation in adults

Jun Yokoi; Takeshi Fujita; Natsumi Uehara; Shinobu Iwaki; Akinobu Kakigi; Ken-Ichi Nibu

doi:10.3389/fneur.2023.1304927

Vestibular function after simultaneous bilateral cochlear implantation in adults

Front Neurol. 2023 Nov 3:14:1304927. doi: 10.3389/fneur.2023.1304927. eCollection 2023.

Authors

Jun Yokoi¹, Takeshi Fujita¹, Natsumi Uehara¹, Shinobu Iwaki¹, Akinobu Kakigi¹, Ken-Ichi Nibu¹

Affiliation

¹ Department of Otolaryngology - Head and Neck Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.

Abstract

Introduction: Binaural hearing enhances speech intelligibility, source localization, and speech comprehension in noisy environments. Although bilateral cochlear implantation (CI) offers several benefits, concerns arise regarding the risk of bilateral postoperative vestibular dysfunction with simultaneous CI. This study aimed to longitudinally evaluate changes in vestibular function in adult patients who underwent simultaneous bilateral CI using minimally invasive electrodes and surgical techniques.

Methods: A retrospective review was conducted on 10 patients who underwent simultaneous bilateral CI at our hospital. Vertigo symptoms and vestibular function test results were examined preoperatively, 1-6 months postoperatively, and 1 year postoperatively. Nystagmus tests, caloric reflex tests, vestibular evoked myogenic potentials (VEMP) measurements, and static stabilometry were performed as vestibular function tests.

Results: Although an initial transient decline in vestibular function was observed, no significant long-term decline was observed in the caloric reflex test, ocular VEMP (oVEMP), or cervical VEMP (cVEMP). Moreover, regardless of the presence or absence of abnormalities in caloric reflex, oVEMP, or cVEMP, no significant deterioration was detected in the static stabilometer test. While two patients reported preoperative dizziness, all patients were symptom-free 1 year postoperatively.

Discussion: The findings suggest that using current minimally invasive electrodes and surgical techniques in simultaneous bilateral CI leads to temporary vestibular function decline postoperatively. However, most patients experience a recovery in function over time, highlighting the potential safety and efficacy of the procedure. Simultaneous bilateral CI surgery is viable, depending on the patient's auditory needs and burden.

Keywords: VEMP; bilateral simultaneous cochlear implantation; cochlear implant; static stabilometry; vestibular function.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by JST FOREST Program, Grant Number JPMJFR215F.