Recent advances in central acute vestibular syndrome of a vascular cause

The value of saccade metrics and VOR gain in detecting a vestibular stroke

OBJECTIVE

A normal video Head Impulse Test is the gold standard in the emergency department to rule-in patients with an acute vestibular syndrome and a stroke. We aimed to compare the diagnostic accuracy of vHIT metrics regarding the vestibulo-ocular reflex gain and the corrective saccades in detecting vestibular strokes.

METHODS

Prospective cross-sectional study (convenience sample) of patients presenting with acute vestibular syndrome in the emergency department of a tertiary referral centre between February 2015 and May 2020. We screened 1677 patients and enrolled 76 patients fulfilling the inclusion criteria of acute vestibular syndrome. All patients underwent video head impulse test with automated and manual data analysis. A delayed MRI served as a gold standard for vestibular stroke confirmation.

RESULTS

Out of 76 patients, 52 were diagnosed with acute unilateral vestibulopathy and 24 with vestibular strokes. The overall accuracy of detecting stroke with an automated vestibulo-ocular reflex gain was 86.8%, compared to 77.6% for cumulative saccade amplitude and automatic saccade mean peak velocity measured by an expert and 71% for cumulative saccade amplitude and saccade mean peak velocity measured automatically. Gain misclassified 13.1% of the patients as false positive or false negative, manual cumulative saccade amplitude and saccade mean peak velocity 22.3%, and automated cumulative saccade amplitude and saccade mean peak velocity 28.9% respectively.

CONCLUSIONS

We found a better accuracy of video head impulse test for the diagnosis of vestibular strokes when using the vestibulo-ocular reflex gain than using saccade metrics. Nevertheless, saccades provide an additional and important information for video head impulse test evaluation. The automated saccade detection algorithm is not yet perfect compared to expert analysis, but it may become a valuable tool for future non-expert video head impulse test evaluations.

Impact of Clinician Training Background and Stroke Location on Bedside Diagnostic Test Accuracy in the Acute Vestibular Syndrome - A Meta-Analysis

OBJECTIVE

Acute dizziness/vertigo is usually due to benign inner-ear causes but is occasionally due to dangerous neurologic ones, particularly stroke. Because symptoms and signs overlap, misdiagnosis is frequent and overuse of neuroimaging is common. We assessed the accuracy of bedside findings to differentiate peripheral vestibular from central neurologic causes.

METHODS

We performed a systematic search (MEDLINE and Embase) to identify studies reporting on diagnostic accuracy of physical examination in adults with acute, prolonged dizziness/vertigo ("acute vestibular syndrome" [AVS]). Diagnostic test properties were calculated for findings. Results were stratified by examiner type and stroke location.

RESULTS

We identified 6,089 citations and included 14 articles representing 10 study cohorts (n = 800). The Head Impulse, Nystagmus, Test of Skew (HINTS) eye movement battery had high sensitivity 95.3% (95% confidence interval [CI] = 92.5-98.1) and specificity 92.6% (95% CI = 88.6-96.5). Sensitivity was similar by examiner type (subspecialists 94.3% [95% CI = 88.2-100.0] vs non-subspecialists 95.0% [95% CI = 91.2-98.9], p = 0.55), but specificity was higher among subspecialists (97.6% [95% CI = 94.9-100.0] vs 89.1% [95% CI = 83.0-95.2], p = 0.007). HINTS sensitivity was lower in anterior cerebellar artery (AICA) than posterior inferior cerebellar artery (PICA) strokes (84.0% [95% CI = 65.3-93.6] vs 97.7% [95% CI = 93.3-99.2], p = 0.014) but was "rescued" by the addition of bedside hearing tests (HINTS+). Severe (grade 3) gait/truncal instability had high specificity 99.2% (95% CI = 97.8-100.0) but low sensitivity 35.8% (95% CI = 5.2-66.5). Early magnetic resonance imaging (MRI)-diffusion-weighted imaging (DWI; within 24-48 hours) was falsely negative in 15% of strokes (sensitivity 85.1% [95% CI = 79.2-91.0]).

INTERPRETATION

In AVS, HINTS examination by appropriately trained clinicians can differentiate peripheral from central causes and has higher diagnostic accuracy for stroke than MRI-DWI in the first 24-48 hours. These techniques should be disseminated to all clinicians evaluating dizziness/vertigo. ANN NEUROL 2023;94:295-308.

Vestibular Autorotation Test: The Differences in Peripheral and Central Acute Vestibular Syndrome

Objective

To evaluate the difference between the vestibular autorotation test (VAT) in the peripheral and central acute vestibular syndrome (AVS). Methodology. Patients with AVS diagnosed by clinical manifestation admitted to the third affiliated hospital of Qiqihar Medical College from January 2019 to January 2021 were enrolled and divided into peripheral AVS (peripheral group) and central AVS (central group) according to the results of the MRI examination.

Results

A total of 332 patients with AVS were recruited, including 282 patients in the peripheral group and 50 patients in the central group. The horizontal gain of both groups showed a downward trend at 2–6 Hz. There was no significant change in the horizontal phase between the two groups at 2–6 Hz. The horizontal gain of the two groups was stable at 2–6 Hz with no significant changes in the horizontal phase between 2–6 Hz in both groups. The central group showed a significantly lower proportion of gain increase coupled with loss and a strikingly higher proportion of gain increase without a loss than in the peripheral group (all P < 0.001).

Conclusion

The increased horizontal and vertical gain of VAT in patients with AVS is of high value in the diagnosis of ACS. Significant differences in the results of VAT in patients with central and peripheral AVS could provide a reference for diagnosis.

Rotatory Vertigo Caused by a Small Hemorrhage in the Superior Temporal Gyrus

Rotatory vertigo is known to have not only peripheral causes, e.g., Meniere's disease, vestibular neuritis, and benign paroxysmal positional vertigo, but also central causes, e.g., stroke, hemorrhage, and tumor. In most cases, central rotatory vertigo is caused by a lesion in the brainstem or cerebellum, but rare cases with a cerebral lesion have also been reported. We herin describe a unique case with acute rotatory vertigo following a small hemorrhage in the left superior temporal gyrus, which probably led to a dysfunction of the visual-vestibular system.

[Dizziness and vertigo in a tertiary ENT emergency department]

BACKGROUND

Although vestibular symptoms are amongst the most frequent reasons for seeking emergency medical help, many patients remain undiagnosed.

OBJECTIVE

In this cross-sectional study, we investigated the spectrum of vertigo and dizziness in a tertiary ear, nose, and throat (ENT) emergency department (ED). Furthermore, we investigated the attendant symptoms, clinical signs, and the diagnostic tests performed.

METHODS

We screened all ED reports from 01/2013 to 12/2013 for adult patients with vestibular symptoms referred to the ENT department.

RESULTS

In total, we found 2596 cases with reported vestibular symptoms in the ED as a main or accompanying complaint. Of these, 286 were referred to the ENT specialist directly (n = 98) or via other major medical specialties (n = 188). Benign paroxysmal positional vertigo (BPPV) was the most frequent diagnosis in our study (n = 46, 16.1%), followed by vestibular neuritis (n = 44, 15.4%), otitis media (n = 20, 7%), and 9 patients (3.1%) had an ischemic stroke or a transient ischemic attack. In 70 (24.5%) cases, dizziness was not further specified.

CONCLUSION

BPPV is the most frequent diagnosis seen in the ED; however, physicians need to document nystagmus more precisely and perform diagnostic tests systematically, in order to make an accurate diagnosis. To avoid misdiagnoses, ED physicians and ENT specialists should be able to recognize central signs in patients with an acute vestibular syndrome. Every fourth patient does not receive a definitive diagnosis. Diagnostic ED workup for patients with dizziness needs further improvement.

Cerebellar infarction presenting with isolated positional vertigo: differentiating factors for benign paroxysmal positional vertigo

BACKGROUND

Isolated central positional vertigo (CPV) due to cerebellar infarction is often difficult to differentiate from benign paroxysmal positional vertigo (BPPV). Here, we aimed to evaluate whether vascular risk factors and serum vitamin D level can differentiate between positional vertigo types.

METHODS

A total of 78 consecutive patients were consecutively enrolled from January 2017. All CPV patients had a National Institutes of Health Stroke Scale score of 0 and cerebellar infarctions confirmed by brain MR imaging. Vascular risk factors and serum 25-hydroxyvitamin D levels were compared between the two groups of patients.

RESULTS

The proportion of men was higher in the CPV than in the BPPV group (p = 0.004). Atrial fibrillation was common in the CPV group on univariate analysis (p = 0.046). However, there were no independent differentiating factors between the two groups. The proportion of patients according to the number of risk factors was significantly different between the two groups (linear by linear association test, p = 0.02). The mean serum 25-hydroxyvitamin D level did not differ. Also, the proportions of vitamin D insufficiency and deficiency did not differ significantly between the two groups.

CONCLUSIONS

Increased number of vascular risk factors including male sex suggested more CPV than BPPV. However, the serum vitamin D level was below the normal range in both groups. Our results demonstrate that serum vitamin D level has little value in the differential diagnosis of positional vertigo. Efforts to identify differentiating factors are warranted, and accumulating evidences including our research may lead to a diagnostic algorithm for isolated positional vertigo.

Vestibular nuclear infarction: Case series and review of the literature

BACKGROUND AND PURPOSE

Acute vestibular syndrome (AVS) is a common cause of emergency admittance and has very rarely been reported due to a vestibular nucleus infarction. Initial magnetic resonance imaging studies (MRIs) including diffusion-weighted images may reveal normal results and even bedside examination tests like HINTS battery which involves head impulse test (HIT), nystagmus and test of skew can be challenging in differing a peripheral vestibulopathy from a central lesion.

METHODS

Four patients seen in the emergency department with AVS and evaluated with HINTS battery, cervical vestibular-evoked myogenic potentials (cVEMP) and cranial MRI revealing infarcts restricted to vestibular nuclei were evaluated.

RESULTS

In two patients spontaneous nystagmus beating towards the unaffected side was present. In one patient spontaneous nystagmus changed direction on looking to the affected side. In the fourth gaze evoked nystagmus was present without any spontaneous nystagmus. In all, HIT was positive to the affected side. In three cVEMPs was studied revealing delayed latency, reduced amplitude p13/n23 potentials on the lesioned side in two of them. Initial MRIs including diffusion-weighted images disclosed acute infarction in the area of the vestibular nuclei in two patients, with normal results in the other two. Follow-up MRI's performed 48 hours later revealed vestibular nuclear infarction.

CONCLUSION

It is not always easy to differentiate small lesions restricted to central vestibular structures from peripheral vestibular lesions both on clinical and radiological grounds. Follow-up cranial MRI is necessary in patients with known vascular risk factors.

Separating posterior-circulation stroke from vestibular neuritis with quantitative vestibular testing

OBJECTIVE

To separate vestibular neuritis (VN) from posteriorcirculation stroke (PCS) using quantitative tests of canal and otolith function.

METHODS

Video Head-Impulse tests (vHIT) were used to assess all three semicircular canal pairs; vestibulo-ocular reflex (VOR) gain and saccade metrics were examined. Cervical and ocular-Vestibular-Evoked Myogenic Potentials (c- and oVEMP) and Subjective Visual Horizontal (SVH) were used to assess otolith function.

RESULTS

For controls (n = 40), PCS (n = 22), and VN (n = 22), mean horizontal-canal VOR-gains were 0.96 ± 0.1, 0.85 ± 0.3 and 0.40 ± 0.2, refixation-saccade prevalence was 71.9 ± 41, 90.7 ± 57, 209.2 ± 62 per 100 impulses and cumulative-saccade amplitudes were 0.9 ± 0.4°, 2.4 ± 2.2°, 8.0 ± 3.5°. Abnormality-rates for cVEMP, oVEMP and SVH were 38%, 9%, 72% for PCS, and 43%, 50%, 91% for VN. A gain ≤0.68, refixation-saccade prevalence of ≥135% and cumulative-saccade amplitudes ≥5.3° separated VN from PCS with sensitivities of 95.5%, 95.5%, and 81.8%, and specificities of 68.2%, 86.4% and 95.5%. VOR-gain and saccade prevalence when combined, separated VN from PCS with a sensitivity and specificity of 90.9%. Abnormal oVEMP asymmetry-ratios were of low sensitivity (50%) but high specificity (90.9%) for separating VN from PCS.

CONCLUSION

vHIT provided the best separation of VN from PCS. VOR-gain, refixation-saccade prevalence and amplitude were effective discriminators of VN from PCS.

SIGNIFICANCE

vHIT and oVEMP could assist early identification of the aetiology of Acute Vestibular Syndrome in the Emergency Room.

Acute and episodic vestibular syndromes caused by ischemic stroke: predilection sites and risk factors

Objective

This study was performed to investigate the predilection sites of acute vestibular syndrome (AVS) and episodic vestibular syndrome (EVS) caused by acute infarcts.

Methods

This retrospective cohort study was performed at a stroke center in a tertiary teaching hospital. We diagnosed patients with AVS/EVS caused by acute ischemic stroke using diffusion-weighted imaging (DWI) and magnetic resonance angiography.

Results

Among all patients with AVS/EVS, 68 had DWI-positive ischemic events and 113 had DWI-negative ischemic events. Of the 68 patients with positive DWI findings, 42.6% had acute infarcts in the anterior circulation and 41.2% had acute infarcts in the posterior circulation. The main stroke predilection sites were the insular cortex (22.1%) and posterior thalamus (11.8%). Large vessel stenosis/occlusion (odds ratio, 0.12; 95% confidence interval, 0.04–0.36) and focal neurological symptoms/signs (odds ratio, 0.27; 95% confidence interval, 0.10–0.72) were significantly associated with the risk of AVS/EVS in patients with acute ischemic stroke.

Conclusions

The main predilection sites of AVS/EVS caused by ischemic stroke are the insular cortex and posterior thalamus. The risk of AVS/EVS is associated with large vessel stenosis and focal symptoms.

Acute dizziness with potential life-threatening event: A case series from single ICU

BACKGROUND

Whether the acute dizziness would be associated with potentially life-threatening event, which was previously unknown.

METHODS

Between Jan 2014 and Dec 2016, We performed a retrospective survey to investigate the clinical data of patients with acute dizziness from an intensive care unit (ICU) in China. Inclusion criteria for all cases were presented with acute dizziness at onset, and then with a potentially life-threatening event. Baseline data and 30-days outcomes were collected.

RESULTS

Approximately 1.0% of ICU patients had an acute dizziness with potentially life-threatening events. The median age of patients was 60 years (range 23 to 81 years), male: female ratio was 1.8:1. The causes of acute dizziness included focal cerebral hemorrhage in 15 cases (60%), shock in 7cases (28%), and cerebral infarction in 3 cases (12%). The most frequent potentially life-threatening event was acute brain failure (24/25), and the most common cause leading to brain failure was the lesion enlarged (54.2%, including hematoma enlargement in 8 cases, large area infarction or new infarction in 3 cases, and intraventricular hemorrhage in 2 cases). The second potentially life-threatening event was septic shock/secondary sepsis (45.8%). The fatality rate for all life- threatening events was in 64%. Compared with the survival group, the patients with lesion enlarged (56.3% vs. 11.1%, p < 0.05), acute respiratory failure (93.8% vs. 55.6% p < 0.05), lactate level (5.3 mmol/l vs. 1.3 mmol/l, p < 0.05), and Sequential Organ Failure Assessment (SOFA) score (6.9 vs. 3.4, p < 0.0001) in the non-survival group were significantly higher, while late mean arterial blood pressure (84.6 mmHg vs.124 mmHg, p < 0.0001), GCS score (5.0 score vs. 15 score, p < 0.0001) in the non-survival group were significantly lower.

CONCLUSION

Acute dizziness with potentially life-threatening events accounts for about 1% of adult ICU patients. Acute dizziness in ICU patients is associated with a high risk of death within 30 days of onset.

Acute vestibular asymmetry disorder: a new disease entity in acute vestibular syndrome?

BACKGROUND

Acute vestibular syndrome (AVS) is characterized by the rapid onset of vertigo, nausea, vomiting and gait unsteadiness, which lasts for days.

AIMS/OBJECTIVES

We report cases as acute vestibular asymmetry disorder (AVAD), with presentations that mimic vestibular neuritis (VN) but without central lesions.

MATERIALS AND METHODS

We retrospectively reviewed records of patients presenting with acute spontaneous vertigo lasting more than 24 h from January 2011 to June 2016. Among 341 patients, five showed different findings that did not indicate either VN or stroke. We analyzed the clinical features and vestibular assessments of these patients.

RESULTS

All five patients showed spontaneous nystagmus continuing for several days. However, head impulse tests (HITs) did not reveal a corrective saccade. Brain magnetic resonance imaging showed no abnormal lesions. The bithermal caloric test revealed directional preponderance without canal paresis. Finally, the slow harmonic test of the rotatory chair revealed unilateral high gain and phase within the normal range, but a significantly asymmetric response was observed. No patients showed recurrence during follow-up.

CONCLUSIONS AND SIGNIFICANCE

Our study suggests that a normal HIT in AVS is not always a dangerous sign indicating an acute stroke. From our observations, we propose that AVAD would be a new disease entity within AVS.

Clinical and video head impulse test in the diagnosis of posterior circulation stroke presenting as acute vestibular syndrome in the emergency department

INTRODUCTION

Head impulse test (HIT) is the critical bedside examination which differentiates vestibular neuritis (VN) from posterior circulation stroke (PCS) in acute vestibular syndrome (AVS). Video-oculography based HIT (vHIT) may have aadditional strength in making the differentiation.

METHODS

Patients admitted to the emergency department of a tertiary-care medical center with AVS were studied. An emergency specialist and a neurologist performed HIT. vHIT was conducted by an neuro-otology research fellow.

RESULTS

Forty patients 26 male, 14 female with a mean age of 49 years were included in the analyses. Final diagnoses were VN in 24 and PCS in 16 patients.In the VN group, clinical HIT was assessed as abnormal in 19(80%) cases by the emergency specialist and in 20(83%) by the neurologist. In all PCS patients, HIT was recorded as normal both by the emergency specialist and the neurologist (100%).On vHIT, patients with VN had significantly low gain values for both the ipsilesional and contralesional sides when compared with the healthy controls, with significantly lower figures for the ipsilesional side (p < 0.001). All patients in this group had normal DWI-MRI.PCS patients had bilaterally low gain (p < 0.05) on vHIT. However, gain asymmetry was not significant. Subgroup analyses according to presence of brainstem involvement revealed bilateral low gain (p < 0.05) in patients with brainstem infarction (anterior inferior cerebellar artery-posterior inferior cerebellar artery stroke, AICA-PICA stroke) whereas patients with pure cerebellar infarction (posterior inferior cerebellar artery-superior cerebellar artery stroke, PICA-SCA stroke) had gain values similar to healthy controls.With a gain cut-off ≤0.75 and gain asymmetry cut-off ≥17%, as determined by ROC analysis, 100% of PCS patients and 80% of VN patients were correctly diagnosed.

CONCLUSIONS

Clinical HIT, either performed by an emergency specialist or neurologist is equivalent to vHIT gain and gain asymmetry analysis as conducted by neuro-otologist in the diagnosis of PCS, albeit mislabeling about 20% of VN patients. vHIT does not appear to yield additional diagnostic information. These findings indicate the strength of clinical HIT. Pure gain-based vHIT analysis seems limited and needs to be incorporated with saccade analysis.

Recent Advances in Cerebellar Ischemic Stroke Syndromes Causing Vertigo and Hearing Loss

Cerebellar ischemic stroke is one of the common causes of vascular vertigo. It usually accompanies other neurological symptoms or signs, but a small infarct in the cerebellum can present with vertigo without other localizing symptoms. Approximately 11 % of the patients with isolated cerebellar infarction simulated acute peripheral vestibulopathy, and most patients had an infarct in the territory of the medial branch of the posterior inferior cerebellar artery (PICA). A head impulse test can differentiate acute isolated vertigo associated with PICA territory cerebellar infarction from more benign disorders involving the inner ear. Acute hearing loss (AHL) of a vascular cause is mostly associated with cerebellar infarction in the territory of the anterior inferior cerebellar artery (AICA), but PICA territory cerebellar infarction rarely causes AHL. To date, at least eight subgroups of AICA territory infarction have been identified according to the pattern of neurotological presentations, among which the most common pattern of audiovestibular dysfunction is the combined loss of auditory and vestibular functions. Sometimes acute isolated audiovestibular loss can be the initial symptom of impending posterior circulation ischemic stroke (particularly within the territory of the AICA). Audiovestibular loss from cerebellar infarction has a good long-term outcome than previously thought. Approximately half of patients with superior cerebellar artery territory (SCA) cerebellar infarction experienced true vertigo, suggesting that the vertigo and nystagmus in the SCA territory cerebellar infarctions are more common than previously thought. In this article, recent findings on clinical features of vertigo and hearing loss from cerebellar ischemic stroke syndrome are summarized.

Protective effect of the microcatheter placed at the normal vertebral artery in intracranial stent-assisted angioplasty for vertebral artery stenosis: A case report

RATIONALE

A carefully designed intracranial stent-assisted angioplasty (SAA) is presented here that may prevent subsequent branch artery occlusion.

PATIENT CONCERNS

A 72-year-old man with a 3-month history of progressive and intermittent vertigo without any obvious trigger, accompanied by nausea.

DIAGNOSES

Intracranial atherosclerotic disease.

INTERVENTIONS

the patient underwent intracranial SAA in accordance with the procedure described here.

OUTCOMES

The patient's paroxysmal vertigo completely subsided, with no complications during the short-term follow-up.

LESSONS

This novel intracranial SAA procedure is safe and may reduce the risk of subsequent artery occlusion.

Vertebrobasilar system computed tomographic angiography in central vertigo

The incidence of vertigo in the population is 20% to 30% and one-fourth of the cases are related to central causes. The aim of this study was to evaluate computed tomography angiography (CTA) findings of the vertebrobasilar system in central vertigo without stroke.CTA and magnetic resonance images of patients with vertigo were retrospectively evaluated. One hundred twenty-nine patients suspected of having central vertigo according to history, physical examination, and otological and neurological tests without signs of infarction on diffusion-weighted magnetic resonance imaging were included in the study. The control group included 120 patients with similar vascular disease risk factors but without vertigo. Vertebral and basilar artery diameters, hypoplasias, exit-site variations of vertebral artery, vertebrobasilar tortuosity, and stenosis of ≥50% detected on CTA were recorded for all patients. Independent-samples t test was used in variables with normal distribution, and Mann-Whitney U test in non-normal distribution. The difference of categorical variable distribution according to groups was analyzed with χ and/or Fisher exact test.Vertebral artery hypoplasia and ≥50% stenosis were seen more often in the vertigo group (P = 0.000, <0.001). Overall 78 (60.5%) vertigo patients had ≥50% stenosis, 54 (69.2%) had stenosis at V1 segment, 9 (11.5%) at V2 segment, 2 (2.5%) at V3 segment, and 13 (16.6%) at V4 segment. Both vertigo and control groups had similar basilar artery hypoplasia and ≥50% stenosis rates (P = 0.800, >0.05).CTA may be helpful to clarify the association between abnormal CTA findings of vertebral arteries and central vertigo.This article reveals the opportunity to diagnose posterior circulation abnormalities causing central vertigo with a feasible method such as CTA.

Saccadic entropy of head impulses in acute unilateral vestibular loss

BACKGROUND/PURPOSE

To evaluate the complexity of vestibular-ocular reflex (VOR) in patients with acute unilateral vestibular loss (AUVL) via entropy analysis of head impulses.

METHODS

Horizontal head impulse test (HIT) with high-velocity alternating directions was used to evaluate 12 participants with AUVL and 16 healthy volunteers. Wireless electro-oculography and electronic gyrometry were used to acquire eye positional signals and head velocity signals. The eye velocity signals were then obtained through differentiation, band-pass filtering. The approximate entropy of eye velocity to head velocity (R_ApEn) was used to evaluate chaos property. VOR gain, gain asymmetry ratio, and R_ApEn asymmetry ratio were also used to compare the groups.

RESULTS

For the lesion-side HIT of the patient group, the mean VOR gain was significantly lower and the mean R_ApEn was significantly greater compared with both nonlesion-side HIT and healthy controls (p < 0.01, one-way analysis of variance). Both the R_ApEn asymmetry ratio and gain asymmetry ratio of the AUVL group were significantly greater compared with those of the control group (p < 0.05, independent sample t test).

CONCLUSION

Entropy and gain analysis of HIT using wireless electro-oculography system could be used to detect the VOR dysfunctions of AUVL and may become effective methods for evaluating vestibular disorders.

A connection between neurovascular conflicts within the cerebellopontine angle and vestibular neuritis, a case controlled cohort study

This retrospective, observer blinded case-control study aims to compare the prevalence of neurovascular conflicts (NVCs) of the vestibulocochlear nerve and the anterior inferior cerebellar artery (AICA) in patients presenting with clinical signs of acute vestibular neuritis with and without subsequent objective vestibular function loss (VFL). 58 acute cases of clinically suspected acute vestibular neuritis were investigated with same day cranial MRI at a tertiary referral centre and compared to 61 asymptomatic controls. The prevalence of NVCs in cases with objective VFL were also compared to cases without VFL. Radiologists described the NVC as "no contact" (Grade 0), "contact < 2 mm" (Grade 1), "contact > 2 mm" (Grade 2) and "vascular loop presence" (Grade 3) without knowledge of neurotological data. Neurotological data was collected without knowledge of MRI findings. Vestibular function was tested by bithermic caloric irrigation. 26 cases (45%) showed caloric VFL (Group A), whereas 32 (55%) exhibited no VFL (Group B). Group A included 13 cases with NVCs (50%), Group B included 26 NVC cases (82%) (p = 0.012) and the control group included 16 individuals (26%) (p < 0.001 for comparison of all 3 groups). Group B had a significantly higher NVC-Grading than Group A (p = 0.009). There was no statistically significant association between NVCs and either SNHL or tinnitus (p > 0.05). Our results suggest that patients presenting with clinical signs of acute vestibular neuritis who show symmetrical caloric vestibular function test results have a significantly higher NVC prevalence in the cerebellopontine angle.

Failure of Fixation Suppression of Spontaneous Nystagmus in Cerebellar Infarction: Frequency, Pattern, and a Possible Structure

To investigate the frequency and pattern of failure of the fixation suppression (FFS) of spontaneous nystagmus (SN) in unilateral cerebellar infarction, and to identify the structure responsible for FFS, 29 patients with acute, mainly unilateral, isolated cerebellar infarction who had SN with a predominantly horizontal component were enrolled in this study. The ocular fixation index (OFI) was defined as the mean slow phase velocity (SPV) of the horizontal component of SN with fixation divided by the mean SPV of the horizontal component of SN without fixation. The OFI from age- and sex-matched patients with vestibular neuritis was calculated and used as the control data. The FFS of SN was only found in less than half (41 %, 12/29) of the patients. Approximately 65 % (n = 7) of the patients with isolated anterior inferior cerebellar artery territory cerebellar infarction showed FFS, whereas only a quarter (n = 3) of the patients with isolated posterior inferior cerebellar artery (PICA) territory cerebellar infarction showed FFS. The proportion of gaze-evoked nystagmus (6/12 [50 %] vs. 2/17 [12 %], p = 0.04) and deficient gain of ipsilesional pursuit (10/12 [83 %] vs. 6/17 [35 %], p = 0.05) was more frequent in the FFS group than in the group without FFS. Lesion subtraction analysis in isolated PICA territory cerebellar infarction revealed that the nodulus was commonly damaged in patients with FFS, compared to that of patients without FFS. Our study shows that FFS of SN due to acute cerebellar infarction is less common than previously thought and the nodulus may be an important structure for the suppression of SN in humans.

Recent Advances in Understanding Audiovestibular Loss of a Vascular Cause

Acute audiovestibular loss is characterized by abrupt onset of prolonged (lasting days) vertigo and hearing loss. Acute ischemic stroke in the distribution of the anterior inferior cerebellar artery (AICA) is known to be the leading cause of acute audiovestibular loss. So far, eight subgroups of AICA territory infarction have been identified according to the patterns of audiovestibular dysfunctions, among which the most common pattern is the combined loss of auditory and vestibular functions. Unlike inner ear dysfunction of a viral cause, which can commonly present as an isolated vestibular (i.e., vestibular neuritis) or cochlear loss (i.e., sudden deafness), labyrinthine dysfunction of a vascular cause rarely results in isolated loss of vestibular or auditory function. As audiovestibular loss may precede the central symptoms or signs of an ischemic stroke in the posterior circulation, early diagnosis and proper management of audiovestiubular loss may provide a window to prevent the progression of infarction to larger areas of the posterior circulation. A clinician should consider the possibility that acute audiovestibular loss may herald impending AICA territory infarction, especially when patients have basilar artery occlusive disease close to the origin of the AICA on brain MRA. This review aims to highlight the recent advances in understanding audiovestibular loss of a vascular cause and to address its clinical significance.

Clinical Correlation between Perverted Nystagmus and Brain MRI Abnormal Findings

Background and Objectives

To analyze the clinical correlation between perverted nystagmus and brain magnetic resonance imaging (MRI) abnormal findings and to evaluate whether perverted nystagmus is clinically significant results of brain abnormal lesions or not.

Subjects and Methods

We performed medical charts review from January 2008 to July 2014, retrospectively. Patients who were suspected central originated vertigo at Frenzel goggles test were included among patients who visited our hospital. To investigate the correlation with nystagmus suspected central originated vertigo and brain MRI abnormal findings, we confirmed whether performing brain MRI or not. Then we exclude that patients not performed brain MRI.

Results

The number of patients with perverted nystagmus was 15, upbeating was 1 and down-beating was 14. Among these patients, 5 patients have brain MRI abnormal findings. However, 2 patients with MRI abnormal findings were not associated correctly with perverted nystagmus and only 3 patients with perverted nystagmus were considered central originated vertigo and further evaluation and treatment was performed by the department of neurology.

Conclusions

Perverted nystagmus was considered to the abnormalities at brain lesions, especially cerebellum, but neurologic symptoms and further evaluation were needed for exact diagnosis of central originated vertigo.

Clinical evaluation of acute phase nystagmus associated with cerebellar lesions

OBJECTIVES

To determine the characteristics of acute phase nystagmus in patients with cerebellar lesions, and to identify a useful indicator for differentiating central lesions from peripheral lesions.

METHODS

Acute phase nystagmus and the appearance of neurological symptoms were retrospectively investigated in 11 patients with cerebellar stroke.

RESULTS

At the initial visit, there were no patients with vertical nystagmus, direction-changing gaze evoked nystagmus or pure rotatory nystagmus. There were four cases with no nystagmus and seven cases with horizontal nystagmus at the initial visit. There were no neurological symptoms, except for vertigo and hearing loss, in any cases at the initial visit. The direction and type of nystagmus changed with time, and neurological symptoms other than vertigo appeared subsequently to admission.

CONCLUSION

It is important to observe the changes in nystagmus and other neurological findings for the differential diagnosis of central lesions.

Isolated intermittent vertigo: A presenting feature of persistent trigeminal artery

Embryonic carotid – basilar anastomosis when persistent in adult life can present with a variety of neurological symptoms. We present a patient with isolated intermittent vertigo attributable to the embryonic anastomosis and describe the different types of persistent trigeminal artery. A 76-year-old Caucasian man presented with isolated intermittent vertigo and symptoms suggestive of anterior and posterior circulation strokes. Impaired vasomotor reactivity was demonstrated on insonation of the anterior and posterior cerebral arteries in this patient with a persistent left trigeminal artery and 75% stenosis of the left internal carotid artery (ICA). The symptom of intermittent vertigo resolved with carotid endarterectomy. Decreased flow across the stenotic segment of the ICA which subserved the posterior circulation resulted in basilar insufficiency. Hypoperfusion to the flocculonodular lobe supplied by the anterior inferior cerebellar artery is a likely cause for the intermittent vertigo.

Ischemic syndromes causing dizziness and vertigo

Dizziness/vertigo and imbalance are the most common symptoms of vertebrobasilar ischemia. Even though dizziness/vertigo usually accompanies other neurologic symptoms and signs in cerebrovascular disorders, a diagnosis of isolated vascular vertigo is increasing markedly by virtue of recent developments in clinical neurotology and neuroimaging. It is important to differentiate isolated vertigo of a vascular cause from more benign disorders involving the inner ear, since therapeutic strategies and prognosis differ between these two conditions. Over the last decade, we have achieved a marked development in the understanding and diagnosis of vascular dizziness/vertigo. Introduction of diffusion-weighted magnetic resonance imaging (MRI) has greatly enhanced detection of infarctions in patients with vascular dizziness/vertigo, especially in the posterior-circulation territories. However, well-organized bedside neurotologic evaluation is even more sensitive than MRI in detecting acute infarction as a cause of spontaneous prolonged vertigo. Furthermore, detailed evaluation of strategic infarctions has elucidated the function of various vestibular structures of the brainstem and cerebellum. In contrast, diagnosis of isolated labyrinthine infarction still remains a challenge. This diagnostic difficulty also applies to isolated transient dizziness/vertigo of vascular origin. Regarding the common nonlacunar mechanisms in the acute vestibular syndrome from small infarctions, individual strategies may be indicated to prevent recurrences of stroke in patients with vascular vertigo.

Vertigo and hearing loss

Symptoms referable to disorders affecting the inner ear and vestibulocochlear nerve (eighth cranial nerve) include dizziness, vertigo, tinnitus, and hearing loss, in various combinations. Similar symptoms may occur with involvement of the central nervous system, principally the brainstem and cerebellum, to which the vestibular and auditory systems are connected. Imaging choices should be tailored to patient symptoms and the clinical context. Computed tomography (CT) should be used primarily to assess bony structures. Magnetic resonance imaging (MRI) should be used primarily to assess soft-tissue structures. Vascular imaging by angiography or venography should be obtained when vascular lesions are suspected. No imaging should be obtained in patients with typical presentations of common peripheral vestibular or auditory disorders. In current clinical practice, neuroimaging is often overused, especially CT in the assessment of acute dizziness and vertigo in the emergency department. Despite low sensitivity for ischemic strokes, CT is often used to rule out neurologic causes. When ischemic stroke is the principal concern in acute vestibular presentations, imaging should almost always be by MRI with diffusion-weighted images, rather than CT. In this chapter, we describe recommended strategies for audiovestibular imaging based on patient symptoms and signs.

Unidentified Bright Objects on Brain Magnetic Resonance Imaging Affect Vestibular Neuritis

Objectives

The aim of this study was to investigate the differences in clinical manifestations of in two groups of vestibular neuritis (VN) patients with or without unidentified bright objects (UBOs).

Methods

A prospective, observational study with 46 patients diagnosed with VN between May 2013 and November 2013 was executed. A caloric test, a cervical vestibular-evoked myogenic potentials (cVEMPs) test, brain magnetic resonance imaging (MRI), spontaneous nystagmus test, head impulse test, and head-shaking nystagmus test were performed.

Results

Of the patients, 56.5% (n=26) were classified as UBO-positive by MRI. These showed lower caloric weakness and more prominent cVEMP asymmetry compared with the UBO-negative group (P<0.05). Total VN (TVN) was the most common in the UBO-positive group (45.0%), followed by superior VN (SVN, 30.0%), and inferior VN (IVN, 25.0%). However, in the UBO-negative group, SVN (75.0%) was the most common, followed by TVN and IVN (P<0.05). The recovery rate was not influenced by UBOs (P>0.05).

Conclusion

UBOs on T2-weighted or fluid attenuated inversion recovery MRI may affect the patterns of the vestibular nerve in patients with VN.

The Effect of Intravenous Dexamethasone on the Nausea Accompanying Vestibular Neuritis: A Preliminary Study

PURPOSE

We undertook a preliminary assessment of the efficacy of administering intravenous dexamethasone (DEX) for relieving the nausea and dizziness accompanying vestibular neuritis (VN).

METHODS

Between November 2013 and October 2014, 26 patients with VN were prospectively enrolled in this study. The patients were randomly assigned to treatment with a combination of 20 mg/d of intravenous metoclopramide, 100 mg of oral dimenhydrinate, and 5 mg/d of intravenous DEX or 20 mg/d of intravenous metoclopramide, 100 mg of oral dimenhydrinate, and intravenous normal saline as a placebo therapy. Patients' subjective assessments of the severity of their nausea and dizziness were recorded using a visual analog scale on the day of admission and 2 days, 3 days, 1 month, and 3 months thereafter. Bedside examinations consisted of spontaneous nystagmus (SPN) assessment, the head shaking nystagmus test, and the head impulse test, which were performed at every follow-up visit.

FINDINGS

The severity of nausea and dizziness was significantly reduced over time (both P < 0.05). However, there was no significant effect of DEX injection on the severity of nausea or dizziness (P > 0.05). The presence of SPN was solely associated with nausea (hazard ratio = 3.34; 95% CI, 1.85-6.02).

IMPLICATIONS

The administration of intravenous DEX did not relieve nausea or dizziness any better than a placebo treatment. However, further research is required to confirm whether there is a dose-dependent effect of DEX on the control of nausea or dizziness in VN.

VOR gain by head impulse video-oculography differentiates acute vestibular neuritis from stroke

OBJECTIVE

Vestibular neuritis is often mimicked by stroke (pseudoneuritis). Vestibular eye movements help discriminate the two conditions. We report vestibulo-ocular reflex (VOR) gain measures in neuritis and stroke presenting acute vestibular syndrome (AVS).

METHODS

Prospective cross-sectional study of AVS (acute continuous vertigo/dizziness lasting >24 h) at two academic centers. We measured horizontal head impulse test (HIT) VOR gains in 26 AVS patients using a video HIT device (ICS Impulse). All patients were assessed within 1 week of symptom onset. Diagnoses were confirmed by clinical examinations, brain magnetic resonance imaging with diffusion-weighted images, and follow-up. Brainstem and cerebellar strokes were classified by vascular territory-posterior inferior cerebellar artery (PICA) or anterior inferior cerebellar artery (AICA).

RESULTS

Diagnoses were vestibular neuritis (n = 16) and posterior fossa stroke (PICA, n = 7; AICA, n = 3). Mean HIT VOR gains (ipsilesional [standard error of the mean], contralesional [standard error of the mean]) were as follows: vestibular neuritis (0.52 [0.04], 0.87 [0.04]); PICA stroke (0.94 [0.04], 0.93 [0.04]); AICA stroke (0.84 [0.10], 0.74 [0.10]). VOR gains were asymmetric in neuritis (unilateral vestibulopathy) and symmetric in PICA stroke (bilaterally normal VOR), whereas gains in AICA stroke were heterogeneous (asymmetric, bilaterally low, or normal). In vestibular neuritis, borderline gains ranged from 0.62 to 0.73. Twenty patients (12 neuritis, six PICA strokes, two AICA strokes) had at least five interpretable HIT trials (for both ears), allowing an appropriate classification based on mean VOR gains per ear. Classifying AVS patients with bilateral VOR mean gains of 0.70 or more as suspected strokes yielded a total diagnostic accuracy of 90%, with stroke sensitivity of 88% and specificity of 92%.

CONCLUSION

Video HIT VOR gains differ between peripheral and central causes of AVS. PICA strokes were readily separated from neuritis using gain measures, but AICA strokes were at risk of being misclassified based on VOR gain alone.

Isolated central vestibular syndrome

Isolated vestibular syndrome may occur all along the vestibular pathways from the peripheral labyrinth to the brain. By virtue of recent developments in clinical neurotology and neuroimaging, however, diagnosis of isolated central vestibulopathy is increasing. Here, we review five distinct syndromes of isolated central vestibular syndrome from lesions restricted to the vestibular nuclei, the nucleus prepositus hypoglossi, the flocculus, the tonsil, and the nodulus, and introduce a new vestibular syndrome from isolated involvement of the inferior cerebellar peduncle. Decreased responses to head impulses do not exclude a central lesion as a cause of isolated vestibular syndrome. Brain imaging, including diffusion-weighted magnetic resonance imaging (MRI), may be falsely negative during the acute phase in patients with isolated vestibular syndrome because of a stroke. Central signs should be sought carefully in patients with isolated vertigo, even when the patients show the features of peripheral vestibulopathy and negative MRIs. Recognition of these isolated central vestibular syndromes would aid in defining the lesions responsible for various vestibular manifestations in central vestibulopathy.

Isolated vascular vertigo

Strokes in the distribution of the posterior circulation may present with vertigo, imbalance, and nystagmus. Although the vertigo due to a posterior circulation stroke is usually associated with other neurologic symptoms or signs, small infarcts involving the cerebellum or brainstem can develop vertigo without other localizing symptoms. Approximately 11% of the patients with an isolated cerebellar infarction present with isolated vertigo, nystagmus, and postural unsteadiness mimicking acute peripheral vestibular disorders. The head impulse test can differentiate acute isolated vertigo associated with cerebellar strokes (particularly within the territory of the posterior inferior cerebellar artery) from more benign disorders involving the inner ear. Acute audiovestibular loss may herald impending infarction in the territory of anterior inferior cerebellar artery. Appropriate bedside evaluation is superior to MRIs for detecting central vascular vertigo syndromes. This article reviews the keys to diagnosis of acute isolated vertigo syndrome due to posterior circulation strokes involving the brainstem and cerebellum.

Isolated vestibular syndrome in posterior circulation stroke: Frequency and involved structures

Dizziness/vertigo is a common symptom of posterior circulation stroke and usually accompanies other neurologic symptoms and signs. Although strokes involving the brainstem or cerebellum may produce isolated vestibular syndrome (isolated vertigo or imbalance), the overall frequency and involved structures of isolated vestibular syndrome in the posterior circulation stroke remain uncertain. Isolated vestibular syndrome occurs in approximately 25% of the patients with posterior circulation stroke, and mostly involves the cerebellum, inferior or superior cerebellar peduncles, and caudal lateral or rostral dorsolateral medulla. The occasional negative neuroimaging in patients with acute isolated vascular vertigo highlights the importance of appropriate bedside evaluation in acute vestibular syndrome.

Small strokes causing severe vertigo: frequency of false-negative MRIs and nonlacunar mechanisms

OBJECTIVE

Describe characteristics of small strokes causing acute vestibular syndrome (AVS).

METHODS

Ambispective cross-sectional study of patients with AVS (acute vertigo or dizziness, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) with at least one stroke risk factor from 1999 to 2011 at a single stroke referral center. Patients underwent nonquantitative HINTS "plus" examination (head impulse, nystagmus, test-of-skew plus hearing), neuroimaging to confirm diagnoses (97% by MRI), and repeat MRI in those with initially normal imaging but clinical signs of a central lesion. We identified patients with diffusion-weighted imaging (DWI) strokes ≤10 mm in axial diameter.

RESULTS

Of 190 high-risk AVS presentations (105 strokes), we found small strokes in 15 patients (median age 64 years, range 41-85). The most common vestibular structure infarcted was the inferior cerebellar peduncle (73%); the most common stroke location was the lateral medulla (60%). Focal neurologic signs were present in only 27%. The HINTS "plus" battery identified small strokes with greater sensitivity than early MRI-DWI (100% vs 47%, p < 0.001). False-negative initial MRIs (6-48 hours) were more common with small strokes than large strokes (53% [n = 8/15] vs 7.8% [n = 7/90], p < 0.001). Nonlacunar stroke mechanisms were responsible in 47%, including 6 vertebral artery occlusions or dissections.

CONCLUSIONS

Small strokes affecting central vestibular projections can present with isolated AVS. The HINTS "plus" hearing battery identifies these patients with greater accuracy than early MRI-DWI, which is falsely negative in half, up to 48 hours after onset. We found nonlacunar mechanisms in half, suggesting greater risk than might otherwise be assumed for patients with such small infarctions.

Towards a concept of disorders of "higher vestibular function"

Background: Vestibular disorders are commonly characterized by a combination of perceptual, ocular motor, postural, and vegetative manifestations, which cause the symptoms of vertigo, nystagmus, ataxia, and nausea. Multisensory convergence and numerous polysynaptic pathways link the bilaterally organized central vestibular network with limbic, hippocampal, cerebellar, and non-vestibular cortex structures to mediate “higher” cognitive functions.

Anatomical classification of vestibular disorders: The traditional classification of vestibular disorders is based on the anatomical site of the lesion. While it distinguishes between the peripheral and the central vestibular systems, certain weaknesses become apparent when applied clinically. There are two reasons for this: first, peripheral and central vestibular disorders cannot always be separated by the clinical syndrome; second, a third category, namely disorders of “higher vestibular function”, is missing. These disorders may be caused by peripheral as well as central vestibular lesions.

Functional classification: Here we discuss a new concept of disorders of higher vestibular function which involve cognition and more than one sensory modality. Three conditions are described that exemplify such higher disorders: room tilt illusion, spatial hemineglect, and bilateral vestibulopathy all of which present with deficits of orientation and spatial memory.

Conclusions: Further elaboration of such disorders of higher multisensory functions with respect to lesion site and symptomatology is desirable. The room tilt illusion and spatial hemineglect involve vestibular and visual function to the extent that both conditions can be classified as either disorders of higher vestibular or of higher visual functions. A possible way of separating these disorders in a first step is to determine whether the causative lesion site affects the vestibular or the visual system. For the vestibular system this lesion site may be peripheral or central. The criterion of “higher function” is fulfilled if cognition or senses other than the primarily affected one come into play.

HINTS outperforms ABCD2 to screen for stroke in acute continuous vertigo and dizziness

OBJECTIVES

Dizziness and vertigo account for about 4 million emergency department (ED) visits annually in the United States, and some 160,000 to 240,000 (4% to 6%) have cerebrovascular causes. Stroke diagnosis in ED patients with vertigo/dizziness is challenging because the majority have no obvious focal neurologic signs at initial presentation. The authors sought to compare the accuracy of two previously published approaches purported to be useful in bedside screening for possible stroke in dizziness: a clinical decision rule (head impulse, nystagmus type, test of skew [HINTS]) and a risk stratification rule (age, blood pressure, clinical features, duration of symptoms, diabetes [ABCD2]).

METHODS

This was a cross-sectional study of high-risk patients (more than one stroke risk factor) with acute vestibular syndrome (AVS; acute, persistent vertigo or dizziness with nystagmus, plus nausea or vomiting, head motion intolerance, and new gait unsteadiness) at a single academic center. All underwent neurootologic examination, neuroimaging (97.4% by magnetic resonance imaging [MRI]), and follow-up. ABCD2 risk scores (0-7 points), using the recommended cutoff of ≥4 for stroke, were compared to a three-component eye movement battery (HINTS). Sensitivity, specificity, and positive and negative likelihood ratios (LR+, LR-) were assessed for stroke and other central causes, and the results were stratified by age. False-negative initial neuroimaging was also assessed.

RESULTS

A total of 190 adult AVS patients were assessed (1999-2012). Median age was 60.5 years (range = 18 to 92 years; interquartile range [IQR] = 52.0 to 70.0 years); 60.5% were men. Final diagnoses were vestibular neuritis (34.7%), posterior fossa stroke (59.5% [105 infarctions, eight hemorrhages]), and other central causes (5.8%). Median ABCD2 was 4.0 (range = 2 to 7; IQR = 3.0 to 4.0). ABCD2 ≥ 4 for stroke had sensitivity of 61.1%, specificity of 62.3%, LR+ of 1.62, and LR- of 0.62; sensitivity was lower for those younger than 60 years old (28.9%). HINTS stroke sensitivity was 96.5%, specificity was 84.4%, LR+ was 6.19, and LR- was 0.04 and did not vary by age. For any central lesion, sensitivity was 96.8%, specificity was 98.5%, LR+ was 63.9, and LR- was 0.03 for HINTS, and sensitivity was 99.2%, specificity was 97.0%, LR+ was 32.7, and LR- was 0.01 for HINTS "plus" (any new hearing loss added to HINTS). Initial MRIs were falsely negative in 15 of 105 (14.3%) infarctions; all but one was obtained before 48 hours after onset, and all were confirmed by delayed MRI.

CONCLUSIONS

HINTS substantially outperforms ABCD2 for stroke diagnosis in ED patients with AVS. It also outperforms MRI obtained within the first 2 days after symptom onset. While HINTS testing has traditionally been performed by specialists, methods for empowering emergency physicians (EPs) to leverage this approach for stroke screening in dizziness should be investigated.

Peripheral vestibular disorders

PURPOSE OF REVIEW

First, to update the diagnosis, pathophysiology, and treatment of the most frequent peripheral vestibular disorders. Second, to identify those disorders for which the diagnostic criteria are still deficient and treatment trials are still lacking.

RECENT FINDINGS

Bilateral vestibulopathy can be reliably diagnosed by the head-impulse test, caloric irrigation, and vestibular-evoked myogenic potentials. A new frequent subtype has been described: cerebellar ataxia, neuropathy, and vestibular areflexia syndrome. Benign paroxysmal positioning vertigo can be easily diagnosed and effectively treated. Vestibular neuritis is most likely caused by the reactivation of a herpes simplex type 1 infection; the inferior vestibular nerve subtype is now well established. More evidence is needed that the recovery can be improved by corticosteroids. Endolymphatic hydrops in Menière's disease can be depicted by high-resolution MRI after transtympanic gadolinium injection; a high-dosage and long-term prophylactic treatment with betahistine is evidently effective. Its mechanism of action is most likely an increase in the inner-ear blood flow. Vestibular paroxysmia is now a well established entity; carbamazepine is the treatment of first choice. Superior canal dehiscence syndrome can be reliably diagnosed; the best current treatment option is canal plugging.

SUMMARY

Although progress has been made in the diagnosis and treatment of most peripheral vestibular disorders, more state-of-the-art trials are needed on the treatment of bilateral vestibulopathy to prove the efficacy of balance training, of vestibular neuritis (in terms of recovery of peripheral vestibular function and central compensation), of vestibular paroxysmia to prove the effects of carbamazepine, and of Menière's disease to find the optimal dosage of betahistine.