Vestibular Dysfunctions in Sudden Sensorineural Hearing Loss: A Systematic Review and Meta-analysis

Abstract

Background: Sudden sensorineural hearing loss (SSHL) not only involves cochlear function but might also be accompanied by vestibular disturbances. The assessment of vestibular function could be of great relevance in SSHL.

Objective: To investigate the prevalence of vestibulocochlear lesions in SSHL and the correlation of specific vestibular organs with hearing prognosis.

Data sources: A complete literature search of eligible studies in the PubMed and EMBASE databases was performed.

Study selection: For our aim, studies that focused on vestibular examination in the case of SSHL were retrieved, including caloric tests, cervical vestibular-evoked myogenic potential (cVEMP) tests, or ocular vestibular-evoked myogenic potential (oVEMP) tests.

Results: Of the 18 studies included, a caloric test was performed in 16 studies, cVEMP in 13 studies, and oVEMP in 5 studies, and together the studies included a total population of 1,468 subjects. The scores on the Agency for Healthcare Research and Quality (AHRQ) questionnaire ranged from 6 to 11. These results indicated that the most commonly damaged vestibular organ in SSHL was the utricle and superior vestibular pathway (U + S) followed by the lateral semicircular canal and superior vestibular pathway (LSC + S), the saccule and inferior vestibular pathway (S + I), and the cochlea only (C only). The meta-analysis indicated that SSHL patients with vertigo have a statistically increased risk of vestibular organ lesions compared with those without vertigo, including the LSC + S subgroup (OR = 4.89, 95% CI = 1.20-19.93, I2 = 80%, p = 0.03) and the S + I subgroup (OR = 3.58, 95% CI = 1.61-7.95, I2 = 0%, p = 0.002). The pooled possibility of hearing recovery within the LSC + S lesion group was less than half that of the non-LSC + S lesion group (OR = 0.24, 95% CI = 0.11-0.52, I2 = 68%, p = 0.0003).

Conclusion: This study shows the relevance of vestibular damage concomitant with SSHL and that SSHL patients with vertigo are at an increased risk of vestibular organ lesions compared with patients without vertigo. LSC + S lesions thus appear to be a critical variable that influence the possibility of hearing improvement in SSHL.

Keywords: caloric test; cervical vestibular-evoked myogenic potential; meta-analysis; ocular vestibular-evoked myogenic potential; sudden sensorineural hearing loss; vertigo; vestibular dysfunction.

Figures

Figure 1

Flow chart of the study selection for the meta-analysis.

Figure 2

Summary of audio-vestibular abnormalities in SSHL. (A) Schematic diagram of the vestibulocochlear lesion patterns, including the cochlea, saccule, utricle, and lateral semicircular canal. (B) Distributions of vestibular test abnormalities of all 18 studies, including 16 by caloric test, 13 by cervical vestibular-evoked myogenic potential test (cVEMP), and 5 by ocular vestibular-evoked myogenic potential test (oVEMP). (C) Percentage of inner ear lesion locations in the included studies––LSC + S, abnormal caloric test; S + I, abnormal cVEMP test; U + S, abnormal oVEMP test; and C only, cochlear impairment only. (D) Table of clinical tests performed, organs involved, and their corresponding innervation.

Figure 3

Pooled event rate of inner ear organ lesion locations. (A) Pooled occurrence rate of lateral semicircular canal lesion and superior vestibular nerve (LSC + S). (B) Pooled occurrence rate of saccule and inferior vestibular nerve lesion (S + I). (C) Pooled occurrence rate of utricle and superior vestibular nerve lesion (U + S). (D) Pooled occurrence rate of cochlea-only lesion (C only). Random, random-effect method; fixed, fixed-effect method.

Figure 4

Funnel plots for the evaluation of publication bias. (A) Funnel plot of the included studies in the meta-analysis of pooled proportions within the LSC + S subgroup. (B) Funnel plot of the included studies in the meta-analysis of pooled proportions within the S + I subgroup. (C) Funnel plot of the included studies in the meta-analysis of pooled proportions within the U + S subgroup. (D) Funnel plot of the included studies in the meta-analysis of pooled proportions within the C only subgroup.

Figure 5

Forest plots of the synthesized data from the selected studies. (A) Comparison of the occurrence rate of lateral semicircular canal and superior vestibular nerve lesion (LSC + S) between the vertigo and non-vertigo groups. (B) Comparison of the occurrence rate of saccule and inferior vestibular nerve lesion (S + I) between the vertigo and non-vertigo groups. OR, odds ratio; M–H, Mantel–Haenszel method; random, random-effect method; fixed, fixed-effect method.

Figure 6

Funnel plots for the evaluation of publication bias. (A) Funnel plot of the included studies in the meta-analysis of the occurrence rate of lateral semicircular canal and superior vestibular nerve lesion (LSC + S). (B) Funnel plot of the included studies in the meta-analysis of the occurrence rate of saccule and inferior vestibular nerve lesion (S + I). MD, mean difference; OR, odds ratio.

Figure 7

Forest plots of synthesized data from the selected studies. (A) Comparison of hearing improvement between the abnormal caloric response and normal caloric response groups. (B) Comparison of hearing improvement between the abnormal cVEMP response and normal cVEMP response groups. OR, odds ratio; M–H, Mantel–Haenszel method; random, random-effect method; fixed, fixed-effect method.

Figure 8

Funnel plots for the evaluation of publication bias. (A) Funnel plot of the included studies in the meta-analysis of hearing improvement between the abnormal caloric response and normal caloric response groups. (B) Funnel plot of the included studies of hearing recovery rate between the abnormal cVEMP response and normal cVEMP response groups. MD, mean difference; OR, odds ratio.

Figure 9

Sensitivity analysis of the association of the presence or absence of caloric response (A) and cVEMP response (B) in the hearing recovery rate in SSHL.