Skull Vibration-Induced Nystagmus Test in a Human Model of Horizontal Canal Plugging.

Georges Dumas,Sébastien Schmerber,Philippe Perrin,Hella Chaney-Vuong,Lea Fath,Anne Charpiot,Christol Fabre

doi:10.3390/audiolres11030028

Abstract

Background/Aim: the aim of this study was to assess the skull vibration-induced nystagmus test (SVINT) results and vestibular residual function after horizontal semicircular canal (HSCC) plugging. Methods: In this retrospective chart review performed in a tertiary referral center, 11 patients who underwent unilateral horizontal semicircular canal plugging (uHSCCP) for disabling Menière’s disease (MD) were included. The skull vibration-induced nystagmus (SVIN) slow-phase velocity (SPV) was compared with the results of the caloric test (CaT), video head impulse test (VHIT), and cervical vestibular-evoked myogenic potentials (cVEMP) performed on the same day. Results: Overall, 10 patients had a strong SVIN beating toward the intact side (Horizontal SVIN-SPV: 8.8°/s ± 5.6°/s), 10 had a significant or severe ipsilateral CaT hypofunction, 10 had an ipsilateral horizontal VHIT gain impairment, and 3 had altered cVEMP on the operated side. Five had sensorineural hearing worsening. SVIN-positive results were correlated with CaT and horizontal VHIT (HVHIT) results (p < 0.05) but not with cVEMP. SVIN-SPV was correlated with CaT hypofunction in % (p < 0.05). Comparison of pre- and postoperative CaT % hypofunction showed a significant worsening (p = 0.028). Conclusion: SVINT results in a human model of horizontal canal plugging are well correlated with vestibular tests exploring horizontal canal function, but not with cVEMP. SVINT always showed a strong lesional nystagmus beating away from the lesion side. SVIN acts as a good marker of HSCC function. This surgical technique showed invasiveness regarding horizontal canal vestibular function.

Highlights

Horizontal canal plugging has recently been described in disabling Menière’s disease (MD) treatment in selected patients with severe pure rotatory attacks of vertigo in the horizontal plane [1]
Background/Aim: the aim of this study was to assess the skull vibration-induced nystagmus test (SVINT) results and vestibular residual function after horizontal semicircular canal (HSCC) plugging. In this retrospective chart review performed in a tertiary referral center, 11 patients who underwent unilateral horizontal semicircular canal plugging for disabling Menière’s disease (MD) were included
SVINT was positive with a VIN beating toward the intact side in 10/11 cases (91%), with mean slow-phase velocity (SPV) value: 8.8◦/s ± 5.6◦/s

Summary

Introduction

Horizontal canal plugging has recently been described in disabling Menière’s disease (MD) treatment in selected patients with severe pure rotatory attacks of vertigo in the horizontal plane [1] This supposed minimal invasive surgery aims at diminishing horizontal semicircular canal (HSCC) function and ablate endolymphatic liquid movement while preserving anatomical integrity of inner ear sensory cells (Figure 1). Skull vibrations or bone-conducted vibrations stimulate type I inner ear hair cells of both canal and otolith structures at 100 Hz [5] and phase-locked AP responses are recorded on irregular discharging neural fibers At such high frequencies type I inner ear hair cells and hair bundles are directly mobilized by the liquid wave induced by vibrations, as suggested by Curthoys [5,6,7]. The type I inner ear hair cells are located at the crest of the cupula and are more sensitive and vulnerable to forces exerted on the endolymphatic liquid than type II inner ear hair cells located at the base of cupula [5]

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