Vestibular evoked myogenic potentials in patients with idiopathic bilateral vestibulopathy. Report of three cases

Recent advances in idiopathic bilateral vestibulopathy: a literature review

Background

Idiopathic bilateral vestibulopathy (IBV) is an acquired bilateral peripheral vestibular dysfunction of unknown etiology, with persistent unsteadiness but without sensorineural hearing loss (SNHL) other than age-related hearing loss (ARHL).

Main text

The prevalence of IBV is unknown. The most common symptom is persistent unsteadiness, particularly in darkness and/or on uneven ground. The other main symptom is oscillopsia during head and body movements. IBV is neither associated with SNHL, except for ARHL, nor any other neurological dysfunction that causes balance disorders. The clinical time course of IBV can generally be divided into two main types: progressive type and sequential type. The progressive type involves gradually progressive persistent unsteadiness without episodes of vertigo. The sequential type involves recurrent vertigo attacks accompanied by persistent unsteadiness. Originally, IBV was found to exhibit bilateral dysfunction in the lateral semicircular canals (LSCCs) and the superior vestibular nerve (SVN) system. However, recently, with the development of more sophisticated vestibular function tests of the otolith organs and vertical semicircular canals, it has been revealed that IBV involves peripheral vestibular lesions other than those already identified in the LSCC and the SVN system. Furthermore, novel subtypes of IBV that do not involve bilateral dysfunction of the LSCC and/or the SVN system have been proposed. Therapeutically, exercise-based vestibular rehabilitation in adult bilateral vestibulopathy (BVP) patients has resulted in improved gaze and postural stability moderately. There are several technical approaches for the treatment of BVP such as vestibular implants, sensory substitution devices and noisy galvanic vestibular stimulation.

Conclusions

Combined use of various vestibular function tests, including recently developed tests, revealed the diversity of lesion sites in IBV. Further studies are required to determine the therapeutic effects of the technical approaches on IBV.

Full Spectrum of Reported Symptoms of Bilateral Vestibulopathy Needs Further Investigation-A Systematic Review

Objective

To systematically review the symptoms reported by patients with bilateral vestibulopathy (BV) in clinical studies and case reports. This would serve as the first step in establishing a validated patient-reported outcome measures (PROM) for BV.

Methods

A search on symptoms reported by patients with BV was performed in PubMed, and all publications covering these symptoms were included. Exclusion criteria comprised reviews and insufficient details about the frequency of occurrence of symptoms.

Results

1,442 articles were retrieved. 88 studies were included (41 clinical studies, 47 case reports). In consensus, 68 descriptions of symptoms were classified into 6 common and generic symptoms. Frequency of symptoms in clinical studies and case reports were reviewed, respectively; imbalance (91 and 86%), chronic dizziness (58 and 62%), oscillopsia (50 and 70%), and recurrent vertigo (33 and 67%). BV could be accompanied by hearing loss (33 and 43%) and tinnitus (15 and 36%). 15 clinical studies and 10 case reports reported symptoms beyond vestibular and hearing deficits such as limited social activities, depression, concentration, and memory impairment and reduced quality of life in general.

Conclusion

The literature on BV symptomatology mainly focuses on classic symptoms such as imbalance and oscillopsia, while only few report additional symptoms such as cognitive memory impairment and performing dual tasks. In fact, none of the reviewed clinical studies and case reports provided a comprehensive overview of BV symptoms. To develop a validated PROM, qualitative research using semi-structured and unstructured interviews is needed to explore the full spectrum of BV symptoms.

Vestibular-Evoked Myogenic Potentials in Bilateral Vestibulopathy

Bilateral vestibulopathy (BVP) is a chronic condition in which patients have a reduction or absence of vestibular function in both ears. BVP is characterized by bilateral reduction of horizontal canal responses; however, there is increasing evidence that otolith function can also be affected. Cervical and ocular vestibular-evoked myogenic potentials (cVEMPs/oVEMPs) are relatively new tests of otolith function that can be used to test the saccule and utricle of both ears independently. Studies to date show that cVEMPs and oVEMPs are often small or absent in BVP but are in the normal range in a significant proportion of patients. The variability in otolith function is partly due to the heterogeneous nature of BVP but is also due to false negative and positive responses that occur because of the large range of normal VEMP amplitudes. Due to their variability, VEMPs are not part of the diagnosis of BVP; however, they are helpful complementary tests that can provide information about the extent of disease within the labyrinth. This article is a review of the use of VEMPs in BVP, summarizing the available data on VEMP abnormalities in patients and discussing the limitations of VEMPs in diagnosing bilateral loss of otolith function.

Characteristics of vertigo and the affected vestibular nerve systems in idiopathic bilateral vestibulopathy

CONCLUSION

Vertigo attacks in IBV patients involving both the superior and inferior vestibular nerve systems were significantly more severe than vertigo attacks in patients with selective involvement of the inferior vestibular nerve system alone.

OBJECTIVE

To investigate the relationship between the frequency and duration of vertigo and the affected vestibular nerve system in idiopathic bilateral vestibulopathy (IBV).

METHODS

This study categorized 44 IBV patients into the following three sub-groups according to the affected vestibular nerve system: superior, inferior, and mixed type. These patients were also categorized into the following three sub-groups according to their clinical time course: progressive type showing no episodes of vertigo, sequential type showing recurrent vertigo attacks and single-attack type showing a single episode of vertigo.

RESULTS

Ten, 11 and 23 patients were classified as the superior, the inferior, and the mixed type, respectively. Seventeen, 23, and four patients were classified as the progressive, the sequential, and the single-attack type, respectively. For the patients having one or more vertigo attacks, the duration of the vertigo attack was longer than 24 h in 69% of the mixed type, and the duration of vertigo in the mixed type was significantly longer than that in the inferior type (p < 0.05).

Persistent otolith dysfunction even after successful repositioning in benign paroxysmal positional vertigo

To evaluate utricular and saccular function during the acute and resolved phases of BPPV, ocular and cervical vestibular evoked myogenic potentials (VEMPs) were studied in 112 patients with BPPV and 50 normal controls in a referral-based University Hospital. Ocular (oVEMPs) and cervical VEMPs (cVEMPs) were induced using air-conducted sound (1000Hz tone burst, 100dB normal hearing level) at the time of initial diagnosis and 2 months after successful repositioning in patients with BPPV, and the results were compared with those of the controls. Abnormalities of cVEMPs and oVEMPs in patients with BPPV were prevalent and significantly higher compare to the healthy control group (p<0.01 in each VEMP by chi-square test). In the patient group, difference between the proportions of abnormal responses of cVEMP and oVEMP was not significant in both affected (p=0.37, chi-squared test) and non-affected (p=1.00) ears. The abnormalities were more likely reduced or absent responses rather than delayed ones; reduced or absent responses are 17.6% in cVEMPs (p=0.04, chi-square) and 21.6% in oVEMPs (p<0.01). The non-affected ear in the BPPV group also showed significantly higher abnormalities of cVEMP and oVEMP when compared to the control group. The follow-up VEMPs after repositioning maneuvers were not significantly different compared to the initial values from both stimulated affected and non-affected ears. Although most patients had unilateral BPPV, bilateral otolithic dysfunction was often shown by persistently reduced or absent cervical and ocular VEMPs, suggesting that BPPV may be caused by significant bilateral damage to the otolith organs.

Idiopathic bilateral vestibulopathy: an autoimmune disease?

Bilateral vestibulopathy (BV) is the loss of function of both peripheral labyrinths or of the eighth nerves. Its etiology remains obscure in approximately 20% to 50% of cases (so-called idiopathic bilateral vestibulopathy, IBV). Alternatively, the cause could be viral or vascular; to date, causative gene mutations have not been identified. Other potential disease mechanisms include autoimmune disorders. Antibodies have been detected against inner ear tissue (primarily against vestibular membranous labyrinth). The data suggest that the bulk of anti-labyrinthine autoantibodies may be an epiphenomenon, but a small subgroup of organ-specific autoantibodies may synergize with a cellular response to develop vestibular lesions. The two key symptoms of BV are the following: 1. unsteadiness of gait, particularly in the dark or on uneven ground, and 2. oscillopsia associated with head movements. Episodes of vertigo are reported by patients with IBV, particularly early in the development of vestibular loss. Associated hearing loss seldom occurs in the idiopathic type of this condition. Post-mortem examinations revealed a remarkably selective loss of vestibular hair cells in the vestibular end organs but normal hair cells in the cochlea. The diagnosis is made with a simple bedside test for defective vestibular function. The diagnosis can be confirmed by bithermal caloric testing and pendular body rotation. The therapy is based on steroid treatment, and the early initiation of immunosuppression appears to be essential for therapeutic success.

Cervical vestibular evoked myogenic potentials in primary headache disorders

OBJECTIVE

To determine if cervical vestibular evoked myogenic potentials (cVEMPS) differ in patients with migraine without aura (MoA), vestibular migraine (VM) and tension type headache (TTH).

METHODS

Twenty patients with MoA, 24 patients with VM and 20 patients with TTH were included in the study. Thirty healthy volunteers of comparable age and gender were taken as the control group. The latencies of peaks p13 and n23, peak-to-peak amplitude of p13-n23 divided by a mean prestimulus EMG recorded during cVEMP testing were measured. The amplitude asymmetry between right and left sides was also calculated and taken into consideration. Caloric testing was conducted to check if the results are associated with the results of the cVEMPs.

RESULTS

Five (one on the right, four on the left side) of the 24 patients with VM (20.8%) displayed a unilateral caloric hypofunction. Normal results were recorded from patients with MoA and TTH. p13, n23 latencies and amplitudes of the patient groups were not statistically different from the results of the healthy controls (p>0.05). An amplitude asymmetry between right and left sides exceeding that of the healthy controls was not also present (p>0.05).

CONCLUSIONS

Though a hypofunctioning horizontal semicircular canal was detected in 20.8% of the patients with VM, saccular function seemed to be unaffected. Patients with MoA and TTH did not display any vestibular test abnormality.

SIGNIFICANCE

Primary headache disorders seem to be associated with a normal interictal cVEMP profile.

Semicircular canal, saccular and utricular function in patients with bilateral vestibulopathy: analysis based on etiology

The diagnosis of bilateral vestibulopathy (BV) is typically established based on bilateral semicircular canal dysfunction. The degree to which both otolith organs-the saccule and utricle-are also impaired in BV is not well-established, particularly with respect to the etiology and severity of BV. The aim of this study was to evaluate semicircular canal, saccular and utricular function in patients with BV due to aminoglycoside ototoxicity and bilateral Menière's disease, and with different severities of BV. Caloric and head impulse testing were used as measures of canal function. Cervical vestibular-evoked myogenic potentials (cVEMP) and ocular VEMPs (oVEMP) were used as measures of saccular and utricular function, respectively. We enrolled 34 patients with BV and 55 controls in a prospective case-control study. Patients with BV were less likely to have saccular (61 %) or utricular (64 %) dysfunction relative to canal dysfunction (100 %). Utricular function differed significantly between patients by etiologic group: the poorest function was found in patients with BV due to aminoglycoside toxicity, and the best function in Menière's disease patients. Canal and saccular function did not vary according to etiology. Further, utricular but not saccular function was significantly correlated with canal function. Saccular and utricular function had the strongest association with Dizziness Handicap Inventory scores relative to canal function. These data suggest that when a patient with BV is identified in a clinical context, oVEMP testing is the most sensitive test in distinguishing between aminoglycoside toxicity and bilateral Menière's disease. Both cVEMP and oVEMP testing may be considered to evaluate the functional impact on the patient.

Bilateral Vestibulopathy with Dissociated Deficits in the Superior and Inferior Vestibular Systems

Objectives:

The aim of this study was to reveal the clinical characteristics of dissociated bilateral vestibulopathy (BV) affecting the superior vestibular nerve system on one side and the inferior vestibular nerve system on the other side. It is probable that BV does not always show bilateral deficits of the same vestibular nerve system.

Methods:

In a retrospective study of 2,752 consecutive new patients, 1,560 patients had undergone both caloric testing and cervical vestibular evoked myogenic potential testing. All 1,560 patients had also undergone a battery of tests including standardized neurologic, neuro-otologic, neuro-ophthalmologic, and audiological examinations.

Results:

Forty-three patients (2.8% of 1,560 patients) were given a diagnosis of dissociated BV. Among them, 10 patients (23%) had Meniere's disease and 6 patients (14%) had vestibular neuritis. Eighteen patients (42%) did not have any identifiable disease involving the peripheral vestibule, and 9 patients (21%) could be regarded as having a novel subtype of idiopathic BV.

Conclusions:

Although dissociated BV might be induced by some of the same causes that provoke bilateral vestibular dysfunction, a definite proportion of the patients did not have any identifiable causes of dissociated vestibular dysfunction. Idiopathic cases could be categorized into a novel subtype of idiopathic BV.

Corticosteroids in the treatment of vestibular neuritis: a systematic review and meta-analysis

OBJECTIVE

To systematically review and meta-analyze the results of all randomized controlled trials comparing corticosteroids with placebo for the treatment of patients with vestibular neuritis.

DATA SOURCES

An electronic search was performed in MEDLINE, EMBASE, Cochrane Library, and CENTRAL databases, and then extensive hand-searching was performed for the identification of relevant studies. No time and language limitations were applied.

STUDY SELECTION

Prospective randomized controlled trials comparing corticosteroids with placebo for the treatment of patients with vestibular neuritis.

DATA EXTRACTION

Odds ratios (ORs), weighted mean differences (WMD), 95% confidence intervals (CIs), and tests for heterogeneity were reported.

DATA SYNTHESIS

Four studies were eventually identified and systematically reviewed. Meta-analysis was feasible for 3 studies. Regarding the recovery of clinical symptoms, the proportion of patients with clinical recovery at 1 month after the initiation of therapy did not differ significantly between the corticosteroids and placebo groups (OR, 1.45; 95% CI, 0.26-8.01; p = 0.67). The proportion of patients with caloric complete recovery was significantly different between the corticosteroids and placebo groups both at 1 (OR, 12.64; 95% CI, 2.6-61.52; p = 0.002; heterogeneity, p = 0.53; fixed effects model) and 12 months (OR, 3.35; 95% CI, 1.45-7.76; p = 0.005; heterogeneity, p = 0.03; random effects model) after the initiation of therapy. The caloric extent of canal paresis at 12 months after the initiation of therapy seemed to differ significantly between patients who received corticosteroids and those who received placebo (WMD, -12.15; 95% CI, -19.85 to -4.46; p < 0.05; heterogeneity, p < 0.05; random effects model).

CONCLUSION

The present systematic review and meta-analysis, based on the currently available evidence, suggests that corticosteroids improve only the caloric extent and recovery of canal paresis of patients with vestibular neuritis. At present, clinical recovery does not seem be better in patients receiving corticosteroids.

The diagnostic value of vestibular-evoked myogenic potential in patients with vestibular schwannoma

OBJECTIVE

This study examined the diagnostic value of the vestibular-evoked myogenic potential (VEMP) in comparison with the caloric test in patients with vestibular schwannoma (VS).

METHODS

Data were retrospectively collected from 803 consecutive patients who visited our vertigo clinic and underwent vestibular tests. Amongst them, 78 patients were diagnosed as having untreated unilateral VS. VEMP was performed using click and short-tone burst stimulation. The caloric test was performed using ice water. The sensitivity and specificity of each test were evaluated.

RESULTS

Of the 78 patients with VS, 63 had abnormal VEMPs as well as abnormal caloric responses. Of the 725 patients without VS, 382 had normal VEMPs and 416 had normal caloric responses. The sensitivity and specificity of VEMP were 80.8% (95% CI: 72.0-89.5%) and 52.7% (95% CI: 49.1-56.3%), respectively; those of the caloric test were 80.8% (95% CI: 72.0-89.5%) and 57.4% (95% CI: 53.8-61.0%), respectively.

CONCLUSIONS

The sensitivity and specificity of VEMP and the caloric test showed no significant differences.

SIGNIFICANCE

In patients with VS, although the specificity of VEMP was not very high, its sensitivity was high and comparable to that of the caloric test.

Vestibular evoked periocular potentials in Meniere's disease after glycerol testing

OBJECTIVES

The present investigation was specifically designed to evaluate the clinical application of vestibular evoked periocular potentials (VEPPs) in the diagnosis of endolymphatic hydrops.

METHODS

We compared the results of the traditional pure tone audiometry glycerol test with those of the vestibular evoked myogenic potential (VEMP) glycerol test and the VEPP glycerol test in 22 patients affected by unilateral endolymphatic hydrops.

RESULTS

Some patients had positive depletive tests with both VEMPs and VEPPs, and other patients had positive tests with either VEMPs or VEPPs.

CONCLUSIONS

Our outcomes confirmed that vestibular evoked potentials represent a useful additional diagnostic tool in the diagnosis of endolymphatic hydrops. The role of VEPPs in this particular issue was not inferior to that of VEMPs. The outcomes also suggested that not only the saccule, but also the utriculus, may be involved in the genesis of VEPPs.

Inferior vestibular neuritis: 3 cases with clinical features of acute vestibular neuritis, normal calorics but indications of saccular failure

Background

Vestibular neuritis (VN) is commonly diagnosed by demonstration of unilateral vestibular failure, as unilateral loss of caloric response. As this test reflects the function of the superior part of the vestibular nerve only, cases of pure inferior nerve neuritis will be lost.

Case presentations

We describe three patients with symptoms suggestive of VN, but normal calorics. All 3 had unilateral loss of vestibular evoked myogenic potential. A slight, asymptomatic position dependent nystagmus, with the pathological ear down, was observed.

Conclusion

We believe that these patients suffer from pure inferior nerve vestibular neuritis.

Abnormal Vestibular Evoked Myogenic Potentials in the Presence of Normal Caloric Responses

OBJECTIVE

Combined use of vestibular evoked myogenic potential (VEMP) and caloric response testing has enabled us to examine the function of the inferior and superior vestibular nerves separately. Although results of VEMP testing and caloric response testing have been reported for many diseases, a clinical entity showing abnormal VEMP responses but normal caloric test responses has rarely been reported. The aim of the study was to investigate clinical features of diseases showing abnormal VEMP responses with normal caloric test responses.

STUDY DESIGN

Retrospective.

SETTING

University hospital.

PATIENTS

Eight hundred eleven patients with balance problems who had undergone both caloric response and VEMP testing were included in the study.

MAIN OUTCOME MEASURES

The amplitudes and latencies of the first positive-negative peak of the VEMP (p13-n23) were measured.

RESULTS

Forty of the 811 patients (5%) were found to have abnormal VEMP responses with normal caloric test responses. Clinical diagnoses of these patients were Ménière's disease (n = 12), acoustic neuroma (n = 8), sudden deafness with vertigo (n = 6), and other diseases (n = 6). Eight patients could not be diagnosed as having a disease already recognized. Clinical manifestations of these eight patients were rotatory vertigo in six patients and non-rotatory dizziness in two. None of these patients showed abnormalities other than VEMP responses on neurologic or neurotologic examinations.

CONCLUSION

Apart from Ménière's disease, acoustic neuroma, and sudden deafness with vertigo, which are already known as diseases with abnormal VEMP responses but normal caloric test responses, some patients might be diagnosed as having a disease that involves only the inferior vestibular nerve region.

Lesion site in idiopathic bilateral vestibulopathy: a galvanic vestibular-evoked myogenic potential study

CONCLUSION

The result suggests that patients with idiopathic bilateral vestibulopathy may have nerve lesions when the inferior nerve system is affected, while the inferior vestibular nerve system may be spared.

OBJECTIVE

To clarify the lesion site in idiopathic bilateral vestibulopathy, an acquired bilateral vestibulopathy of unknown cause.

MATERIAL AND METHODS

Two 75-year-old males diagnosed with idiopathic bilateral vestibulopathy were enrolled. Both showed absent or highly decreased responses on the caloric test on both sides. They underwent vestibular-evoked myogenic potential (VEMP) testing by means of acoustical and electrical stimulation. As acoustic stimulation, 95 dB nHL clicks and short tone bursts (500 Hz) were presented, while 3 mA (1 ms) short-duration galvanic stimuli were presented as electrical stimulation. Responses were recorded on the sternocleidomastoid muscles.

RESULTS

Both patients showed unilateral absence of VEMPs with both acoustic and short-duration galvanic stimuli.

General vestibular testing

A dysfunction of the vestibular system is commonly characterized by a combination of phenomena involving perceptual, ocular motor, postural, and autonomic manifestations: vertigo/dizziness, nystagmus, ataxia, and nausea. These 4 manifestations correlate with different aspects of vestibular function and emanate from different sites within the central nervous system. The diagnosis of vestibular syndromes always requires interdisciplinary thinking. A detailed history allows early differentiation into 9 categories that serve as a practical guide for differential diagnosis: (1) dizziness and lightheadedness; (2) single or recurrent attacks of vertigo; (3) sustained vertigo; (4) positional/positioning vertigo; (5) oscillopsia; (6) vertigo associated with auditory dysfunction; (7) vertigo associated with brainstem or cerebellar symptoms; (8) vertigo associated with headache; and (9) dizziness or to-and-fro vertigo with postural imbalance. A careful and systematic neuro-ophthalmological and neuro-otological examination is also mandatory, especially to differentiate between central and peripheral vestibular disorders. Important signs are nystagmus, ocular tilt reaction, other central or peripheral ocular motor dysfunctions, or a unilateral or bilateral peripheral vestibular deficit. This deficit can be easily detected by the head-impulse test, the most relevant bedside test for the vestibulo-ocular reflex. Laboratory examinations are used to measure eye movements, to test semicircular canal, otolith, and spatial perceptional function and to determine postural control. It must, however, be kept in mind that all signs and ocular motor and vestibular findings have to be interpreted within the context of the patient's history and a complete neurological examination.

A case of Cronkhite-Canada syndrome with vestibular disturbances

A 66-year-old Japanese man with Cronkhite-Canada syndrome (CCS) presented with complaints of long-lasting dysequilibrium. On neuro-otological examination, he showed gaze-evoked nystagmus at the rightward and leftward gaze, and saccadic pursuit. On the caloric test, he showed no response in either side, and on the head-impulse test he showed bilateral loss of vestibule-ocular reflexes around the yaw axis, while he had bilateral normal responses on the vestibular-evoked myogenic potential testing. Neuro-otological findings suggested that he had lesions in the peripheral vestibular system as well as the central nervous system. Neurological disorders such as sensory neuropathy have been reported in patients with CCS. This patient's balance problems could be due to CCS itself.

Disappearance of click-evoked potentials on the neck of the guinea pig by pharmacological and surgical destruction of the peripheral vestibular afferent system

In order to establish an animal model of acoustically evoked vestibulo-collic reflex, the so-called vestibular evoked myogenic potential in humans, potentials evoked by loud clicks on the neck of the guinea pig were recorded using subjects whose peripheral vestibular endorgans or vestibular afferents had been damaged. Four normal control guinea pigs, four guinea pigs that received an intramuscular injection of gentamicin for 20 days (90 mg/kg/day) and five guinea pigs whose vestibular nerves were surgically sectioned were used in this study. Under general anesthesia with an intraperitoneal injection of pentobarbital sodium (40 mg/kg), auditory brainstem responses (ABRs) were recorded. Then, potentials evoked by loud clicks on the pre-vertebral muscle at the level of the third cervical vertebral bone were recorded using silver ball electrodes. As a result, a distinctive negative peak (NP) with a latency of 6-8 ms was recorded in all animals in the control group. NP was not observed in the gentamicin-administered group while ABR was preserved. After sectioning the vestibular nerve, NP was abolished while ABR was preserved. From these results, NP could be of vestibular origin. These results are in agreement with a previous report of NP using subjects whose cochlea had been damaged pharmacologically.