Vestibular schwannoma mimicking horizontal cupulolithiasis

Paroxysmal Positional Nystagmus in Acoustic Neuroma Patients

The association between acoustic neuroma and positional vertigo with paroxysmal positional nystagmus is relatively rare, but, when present, it certainly represents a challenge for the otoneurologist. There are few reports in the literature on this particular issue, and some questions are still unanswered, particularly regarding the characteristics of positional nystagmus that may distinguish between a true benign paroxysmal vertigo and a positional nystagmus associated with the tumor. We present the videonystagmographic patterns of seven patients with acoustic tumor who had paroxysmal positional nystagmus and analyzed its features. A concomitant true benign paroxysmal positional vertigo may be present during the follow-up of a non-treated patient, as the paroxysmal positional vertigo may be the first symptom of the tumor, and it may show characteristics that are very similar to a posterior semicircular canal canalolithiasis or a horizontal canal "heavy or light cupula". The possible mechanisms are discussed.

Direction-changing spontaneous nystagmus in cerebellopontine angle tumour

The most common symptoms of tumours involving the cerebellopontine angle (CPA) are unilateral sensorineural hearing loss, dizziness, and asymmetric tinnitus. While the clinical manifestations have been well documented in previous studies, the nystagmus findings in these patients have not been thoroughly investigated yet. This study aimed to investigate the incidence of direction-changing spontaneous nystagmus in patients with CPA tumours, evaluate their radiologic characteristics, and gain insight into the mechanisms underlying nystagmus. Direction-changing spontaneous nystagmus was observed in 6 out of 83 patients (7%) with CPA tumours during the 7-year period. Temporal bone magnetic resonance imaging findings revealed the presence of an intrameatal mass in CPA tumours in all six patients with direction-changing spontaneous nystagmus. Vestibular schwannomas were confined within the internal auditory meatus in four patients, and petroclival meningiomas extended into the internal auditory meatus in two patients. The mechanism of direction-changing spontaneous nystagmus may be explained as paroxysmal secondary central hyperactivity in the vestibular nucleus due to the long-standing pressure effect in the vestibular nerve by tumours, or by ephaptic discharges in the vestibular nerve.

Volume quantification of endolymphatic hydrops in patients with vestibular schwannoma

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Origin of vestibular symptoms in patients with VS is unknown.

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Intratympanic gadolinium-enhanced MRI could confirm labyrinthine lesion in VS.

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The volume percentage of the endolymphatic space was more accurate than the area percentage for assessing vestibular EH.

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Vestibular symptoms in patients with VS may originate from peripheral lesions.

Objective

The origin of vestibular symptoms in patients with vestibular schwannoma (VS) is uncertain. We used intratympanic gadolinium-enhanced magnetic resonance imaging (MRI) to confirm the labyrinthine lesions in patients with VS and to explore the features of endolymphatic hydrops (EH) in these patients.

Methods

In total, 66 patients diagnosed with unilateral VS were enrolled in this study and underwent intratympanic gadolinium-enhanced MRI. The borders of the vestibule and endolymph were mapped on the axial MRI images, and the area and volume of vestibule and endolymph were automatically calculated using Osirix software, and the area and volume percentage of vestibular endolymph were obtained.

Results

The area and volume percentages of vestibular endolymph on the affected side were significantly larger than those on the healthy side (both p < 0.001). Using Kendall's W test, we found that the area and volume percentages of vestibular endolymph on the affected side were consistent (p < 0.001), but the consistency was moderate (k = 0.574). The healthy side was also consistent (p < 0.001), and the degree of consistency was moderate (k = 0.444). We used 19.1% as the cut-off point to distinguish the presence or absence of vestibular EH; that is, the volume percentage of vestibular endolymph that was more than 19.1% were defined as the subgroup with hydrops, while the subgroup without hydrops included patients with a baseline level below 19.1%. No volume classification for vestibular EH was proposed. Based on this standard, 11/66 (16.7%) of the patients with VS in this study had vestibular EH. Conclusions.

The volume percentage of the vestibular endolymph was more accurate than the area percentage for assessing vestibular EH. Using 19.1% as the cut-off point to distinguish the presence or absence of vestibular EH, we found that 16.7% of patients with VS had varying degrees of vestibular EH. We believe that the vestibular symptoms in patients with VS may originate from the peripheral lesions.

Rare Disorders of the Vestibular Labyrinth: of Zebras, Chameleons and Wolves in Sheep's Clothing

The differential diagnosis of vertigo syndromes is a challenging issue, as many - and in particular - rare disorders of the vestibular labyrinth can hide behind the very common symptoms of "vertigo" and "dizziness". The following article presents an overview of those rare disorders of the balance organ that are of special interest for the otorhinolaryngologist dealing with vertigo disorders. For a better orientation, these disorders are categorized as acute (AVS), episodic (EVS) and chronic vestibular syndromes (CVS) according to their clinical presentation. The main focus lies on EVS sorted by their duration and the presence/absence of triggering factors (seconds, no triggers: vestibular paroxysmia, Tumarkin attacks; seconds, sound and pressure induced: "third window" syndromes; seconds to minutes, positional: rare variants and differential diagnoses of benign paroxysmal positional vertigo; hours to days, spontaneous: intralabyrinthine schwannomas, endolymphatic sac tumors, autoimmune disorders of the inner ear). Furthermore, rare causes of AVS (inferior vestibular neuritis, otolith organ specific dysfunction, vascular labyrinthine disorders, acute bilateral vestibulopathy) and CVS (chronic bilateral vestibulopathy) are covered. In each case, special emphasis is laid on the decisive diagnostic test for the identification of the rare disease and "red flags" for potentially dangerous disorders (e. g. labyrinthine infarction/hemorrhage). Thus, this chapter may serve as a clinical companion for the otorhinolaryngologist aiding in the efficient diagnosis and treatment of rare disorders of the vestibular labyrinth.

Nystagmus characteristics of healthy controls

BACKGROUND:

Healthy controls exhibit spontaneous and positional nystagmus which needs to be distinguished from pathological nystagmus.

OBJECTIVE:

Define nystagmus characteristics of healthy controls using portable video-oculography.

METHODS:

One-hundred and one asymptomatic community-dwelling adults were prospectively recruited. Participants answered questions regarding their audio-vestibular and headache history and were sub-categorized into migraine/non-migraine groups. Portable video-oculography was conducted in the upright, supine, left- and right-lateral positions, using miniature take-home video glasses.

RESULTS:

Upright position spontaneous nystagmus was found in 30.7% of subjects (slow-phase velocity (SPV)), mean 1.1±2.2 degrees per second (°/s) (range 0.0 – 9.3). Upright position spontaneous nystagmus was horizontal, up-beating or down-beating in 16.7, 7.9 and 5.9% of subjects. Nystagmus in at least one lying position was found in 70.3% of subjects with 56.4% showing nystagmus while supine, and 63.4% in at least one lateral position. While supine, 20.8% of subjects showed up-beating nystagmus, 8.9% showed down-beating, and 26.7% had horizontal nystagmus. In the lateral positions combined, 37.1% displayed horizontal nystagmus on at least one side, while 6.4% showed up-beating, 6.4% showed down-beating. Mean nystagmus SPVs in the supine, right and left lateral positions were 2.2±2.8, 2.7±3.4, and 2.1±3.2°/s. No significant difference was found between migraine and non-migraine groups for nystagmus SPVs, prevalence, vertical vs horizontal fast-phase, or low- vs high-velocity nystagmus (<5 vs > 5°/s).

CONCLUSIONS:

Healthy controls without a history of spontaneous vertigo show low velocity spontaneous and positional nystagmus, highlighting the importance of interictal nystagmus measures when assessing the acutely symptomatic patient.

Characteristics of assessment and treatment in Benign Paroxysmal Positional Vertigo (BPPV)

QUESTION:

Benign Paroxysmal Positional Vertigo (BPPV) is the most common cause of dizziness presenting to specialist vestibular centres and accounts for approximately 20–30% of referrals to these clinics. In spite of the amount of clinical knowledge surrounding its diagnosis and management, the treatment of BPPV remains challenging for even the most experienced clinicians. This study outlines the incidence of BPPV in a specialised vestibular physiotherapy clinics and discusses the various nuances encountered during assessment and treatment of BPPV.

DESIGN:

Observational Study

PARTICIPANTS:

314 patients with various forms of Benign Paroxysmal Positional Vertigo (BPPV)

INTERVENTION:

Canalith repositioning manoeuvres (CRP) for posterior canal (PC) or horizontal canal (HC) BPPV depending on the canal and variant of BPPV.

OUTCOME MEASURES:

Negative Dix-Hallpike (DHP) or Supine roll test (SRT) examination.

RESULTS:

In 91% of cases, PC BPPV was effectively treated in 2 manoeuvres or less. Similarly, 88% of HC BPPV presentations were effectively managed with 2 treatments. Bilateral PC, multiple canal or canal conversions required a greater number of treatments. There was no noticeable difference in treatment outcomes for patients who had nystagmus and symptoms during the Epley manoeuvre (EM) versus those who did not have nystagmus and symptoms throughout the EM. Nineteen percent of patients experienced post treatment down-beating nystagmus (DBN) and vertigo or “otolithic crisis” after the first or even the second consecutive EM.

CONCLUSION:

Based on the data collected, we make several clinical recommendations for assessment and treatment of BPPV. Firstly, repeated testing and treatment of BPPV within the same session is promoted as a safe and effective approach to the management of BPPV with a low risk of canal conversion. Secondly, vertigo and nystagmus throughout the EM is not indicative of treatment success. Thirdly, clinicians must remain vigilant and mindful of the possibility of post treatment otolithic crisis following the treatment of BPPV. This is to ensure patient safety and to prevent possible injurious falls. Our results challenge several clinical assumptions about the assessment and treatment of BPPV including the utility of certain markers of treatment success; hence influencing the current clinical guidelines and clinical practice and paving the way for future studies of the assessment and management of patients with BPPV.

Classification of vestibular signs and examination techniques: Nystagmus and nystagmus-like movements

This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations.

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Benign positional vertigo, its diagnosis, treatment and mimics

The diagnosis of benign positional vertigo (BPV) relies on a history of episodic positional vertigo and a distinctive pattern of nystagmus during provocative positional testing. The direction of the induced nystagmus is specific to the affected canal and the velocity profile reflects the underlying mechanism of canalithiasis (free-floating otoconia within the canal duct) or cupulolithiasis (otoconia adherent to the cupula). We review current theories on the pathophysiology of BPV, the clinical history and examination underlying its diagnosis, and recommended repositioning manoeuvres for each of the BPV subtypes. Disorders other than BPV which may present with a similar history and/or positional nystagmus are discussed.

Central Positional Nystagmus: A Systematic Literature Review

Objective

To provide a systematic review of the clinical and radiological features of lesion-induced central positional nystagmus (CPN) and identify salient characteristics that differentiate central from peripheral positional nystagmus (PN).

Methods

Systematic literature search according to the preferred reporting items for systematic reviews and meta-analysis.

Results

A total of 82 patients from 28 studies met the participants intervention, comparison, outcomes, and study designs criteria for inclusion. An atypical direction of nystagmus for the stimulated canal was reported in 97.5% patients during Dix–Hallpike (D–H) and 54.5% upon supine roll testing. Five types of CPNs were identified during positional testing: positional horizontal nystagmus (pHN) (36.8%), positional downbeating nystagmus (pDBN) (29.2%), positional torsional nystagmus (pTN) (2.1%), positional upbeating nystagmus (pUBN) (2.1%), and a combination of the four profiles (29.9%). CPN was paroxysmal (<60 s) in 85% patients on straight head hanging (SHH), 63.9% on D–H, and 37.5% on supine roll, and had a latency <3 s upon positioning in 94.7% patients in which it was reported. Concurrent vertigo was reportedly present in 63.4% patients and 48.8% demonstrated other neurological signs. Radiologically, in 74.4%, there was mention of cerebellar involvement, isolated brainstem involvement in 8.5%, and 14.6% involved the fourth ventricle.

Conclusion

Currently, there is a lack of robust data on the clinical and radiological characteristics of CPN highlighting the need for better phenotyping of CPN to help differentiate this entity from peripheral causes of PN. With increased awareness of CPN, particularly in the acute setting, we may see a change in the estimated prevalence of CPN and improved clinical markers to promptly identify the frequently sinister underlying causes.

Peripheral Vestibular System Disease in Vestibular Schwannomas: A Human Temporal Bone Study

INTRODUCTION

Dizziness is a common symptom in patients with vestibulo-cochlear schwannoma (VS), and several recent studies have identified this symptom as the single most important concerning the quality of life. Clinical and histological observations regarding hearing loss have suggested that this may be caused by both cochlear and retrocochlear mechanisms. Multiple mechanisms may also be at play in the case of dizziness, which may broaden perspectives of therapeutic approach. This study presents a systematic and detailed assessment of vestibular histopathology in temporal bones from patients with VS.

METHODS

Retrospective analysis of vestibular system histopathology in temporal bones from 17 patients with unilateral VS. The material was obtained from The Copenhagen Temporal Bone Collection.

RESULTS

Vestibular schwannomas were associated with atrophy of the vestibular ganglion, loss of fiber density of the peripheral vestibular nerve branches, and atrophy of the neuroepithelium of the vestibular end organs. In cases with small tumors, peripheral disease occurred only in the tissue structures innervated by the specific nerve from which the tumor originated.

CONCLUSION

Vestibular schwannomas are associated with distinctive disease of the peripheral vestibular tissue structures, suggesting anterograde degeneration and that dizziness in these patients may be caused by deficient peripheral vestibular nerve fibers, neurons, and end organs. In smaller tumors, a highly localized disease occurs, which opens perspectives of differentiated clinical assessment and subsequent, targeted therapy.

Quantitative Vestibular Labyrinthine Otopathology in Temporal Bones with Vestibular Schwannoma

Objective

Dizziness associated with vestibular schwannoma is usually ascribed to retrolabyrinthine mechanisms. The goal of this study was to determine if quantitative peripheral vestibular (labyrinthine) otopathology was present in a series of patients with vestibular schwannoma.

Study Design

Comparative human temporal bone study.

Setting

Otopathology laboratory.

Subjects and Methods

Temporal bones from 12 subjects with unilateral sporadic vestibular schwannoma were included. Based on differential interference contrast microscopy, type I and II vestibular hair cell counts were performed on each vestibular sense organ with minimal autolysis in which the neuroepithelium was oriented perpendicular to the plane of section. Hair cell densities (cells per 0.01-mm2 surface area) and the presence of endolymphatic hydrops and precipitate within the endolymph or perilymph were compared between the tumor ears and the contralateral (control) ears.

Results

Compared with the contralateral ears, vestibular schwannoma ears had significantly more endolymphatic hydrops ( P = .049) and precipitate in the endolymph and perilymph ( P = .005), lower densities of type I and II vestibular hair cells in the lateral canal cristae (mean differences, respectively: 25.2 [ P = .001] and 10.8 [ P < .001]) and utricle (mean differences, respectively: 26.8 and 10.4 [ P < .001]), and lower densities of type I hair cells and the same density of type II hair cells in the saccule (mean differences, respectively: 26.5 [ P < .001] and 0.9 [ P = .46]).

Conclusion

Peripheral vestibular otopathology, manifested as reductions of vestibular hair cell densities, was identified in ears with vestibular schwannoma. Labyrinthine as well as retrolabyrinthine pathology may contribute to tumor-related vestibular dysfunction.