Post cochlear implantation vertigo: ictal nystagmus and audiovestibular test characteristics

Belinda Y. C. Kwok, Allison S. Young, Jonathan H. K. Kong, Catherine S. Birman, Sean Flanagan, Simon L. Greenberg, William P. Gibson, Emma C. Argaet, Luke Fratturo, Jacob M. Pogson, Rachael L. Taylor, Sally M. Rosengren, G. Michael Halmagyi, Miriam S. Welgampola*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Objective: To investigate ictal nystagmus and audiovestibular characteristics in episodic spontaneous vertigo after cochlear implantation (CI). Study Design: Retrospective and prospective case series. Patients: Twenty-one CI patients with episodic spontaneous vertigo after implantation were recruited. Interventions: Patient-initiated home video-oculography recordings were performed during one or more attacks of vertigo, using miniature portable home video-glasses. To assess canal and otolith function, video head-impulse tests (vHITs) and vestibular-evoked myogenic potential tests were conducted. Main Outcome Measures: Nystagmus slow-phase velocities (SPVs), the presence of horizontal direction-changing nystagmus, and post-CI audiovestibular tests. Results: Main final diagnoses were post-CI secondary endolymphatic hydrops (48%) and exacerbation of existing Ménière's disease (29%). Symptomatic patients demonstrated high-velocity horizontal ictal-nystagmus (SPV, 44.2°/s and 68.2°/s in post-CI secondary endolymphatic hydrop and Ménière's disease). Direction-changing nystagmus was observed in 80 and 75%. Two were diagnosed with presumed autoimmune inner ear disease (SPV, 6.6°/s and 172.9°/s). One patient was diagnosed with probable vestibular migraine (15.1°/s). VHIT gains were 0.80 ± 0.20 (lateral), 0.70 ± 0.17 (anterior), and 0.62 ± 0.27 (posterior) in the implanted ear, with abnormal values in 33, 35, and 35% of each canal. Bone-conducted cervical and ocular vestibular-evoked myogenic potentials were asymmetric in 52 and 29% of patients (all lateralized to the implanted ear) with mean asymmetry ratios of 51.2 and 35.7%. Reversible reduction in vHIT gain was recorded in three acutely symptomatic patients. Conclusion: High-velocity, direction-changing nystagmus time-locked with vertigo attacks may be observed in post-CI implant vertigo and may indicate endolymphatic hydrops. Fluctuating vHIT gain may be an additional marker of a recurrent peripheral vestibulopathy.

Original languageEnglish
Pages (from-to)65-74
Number of pages10
JournalOtology and Neurotology
Volume45
Issue number1
Early online date14 Oct 2023
DOIs
Publication statusPublished - Jan 2024

Keywords

  • Audiovestibular tests
  • Cochlear implantation
  • Delayed endolymphatic hydrops
  • Nystagmus
  • Post-CI
  • Vertigo

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