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

A Set of Eight Key Questions Helps to Classify Common Vestibular Disorders-Results From the DizzyReg Patient Registry

Precise history taking is the key to develop a first assumption on the diagnosis of vestibular disorders. Particularly in the primary care setting, algorithms are needed, which are based on a small number of questions and variables only to guide appropriate diagnostic decisions. The aim of this study is to identify a set of such key variables that can be used for preliminary classification of the most common vestibular disorders. A four-step approach was implemented to achieve this aim: (1) we conducted an online expert survey to collect variables that are meaningful for medical history taking, (2) we used qualitative content analysis to structure these variables, (3) we identified matching variables of the patient registry of the German Center for Vertigo and Balance Disorders, and (4) we used classification trees to build a classification model based on these identified variables and to analyze if and how these variables contribute to the classification of common vestibular disorders. We included a total of 1,066 patients with seven common vestibular disorders (mean age of 51.1 years, SD = 15.3, 56% female). Functional dizziness was the most frequent diagnosis (32.5%), followed by vestibular migraine (20.2%) and Menière's disease (13.3%). Using classification trees, we identified eight key variables which can differentiate the seven vestibular disorders with an accuracy of almost 50%. The key questions comprised attack duration, rotational vertigo, hearing problems, turning in bed as a trigger, doing sport or heavy household chores as a trigger, age, having problems with walking in the dark, and vomiting. The presented algorithm showed a high-face validity and can be helpful for taking initial medical history in patients with vertigo and dizziness. Further research is required to evaluate if the identified algorithm can be applied in the primary care setting and to evaluate its external validity.

Approach to the History and Evaluation of Vertigo and Dizziness

PURPOSE OF REVIEW

This article reviews a method of obtaining the medical history of patients presenting with dizziness, vertigo, and imbalance. By combining elements of the history with examination, the goal is to identify patterns and an effective differential diagnosis for this group of patients to help lead to an accurate diagnosis.

RECENT FINDINGS

Studies over the past dozen years have changed the historical approach to patients with dizziness from one based primarily on how the patient describes the sensation of dizziness. This older approach can lead to misdiagnosis, so a preferred method puts greater emphasis on whether the dizziness is acute or chronic, episodic or continuous, or evoked by or brought on by an event or circumstance so that a pattern may be derived that better narrows the differential diagnosis and focused examination can further narrow to a cause or causes.

SUMMARY

Dizziness is a common symptom of many possible causes. This article will help clinicians navigate gathering the history and examination to formulate a working diagnosis in patients affected by dizziness.

Episodic Spontaneous Dizziness

PURPOSE OF REVIEW

Conditions causing recurrent spontaneous episodes of dizziness or vertigo span several medical specialties, making it challenging for clinicians to gain confidence in evaluating and managing the spectrum of episodic vestibular disorders. Patients are often asymptomatic and have normal examinations at the time of evaluation. Thus, diagnosis depends heavily on eliciting key features from the history. Overreliance on symptom quality descriptions commonly leads to misdiagnosis. The goal of this article is to provide the reader with a straightforward approach to the diagnosis and management of conditions that cause episodic spontaneous dizziness.

RECENT FINDINGS

Consensus diagnostic criteria have been established for vestibular migraine, Ménière disease, vestibular paroxysmia, and hemodynamic orthostatic dizziness/vertigo. Vertigo has been recognized as a common symptom in vertebrobasilar ischemia, cardiogenic dizziness, and orthostatic hypotension. Treatment recommendations for vestibular migraine still lack high-quality evidence, but controlled trials are occurring.

SUMMARY

The evaluation should start with a detailed description of the episodes from the patient and any observers. Rather than focusing first on whether the symptom quality is most consistent with vertigo, dizziness, lightheadedness, or unsteadiness, the clinician should clarify the timing (episode frequency and duration), possible triggers or circumstances (eg, position changes, upright posture), and accompanying symptoms. History should identify any auditory symptoms, migraine features, posterior circulation ischemic symptoms, vascular risk factors, clues for anxiety, and potentially relevant medications. Carefully selected testing can help secure the diagnosis, but excessive and indiscriminate testing can lead to more confusion. Treatments for these conditions are vastly different, so an accurate diagnosis is critical.

Clinical and VNG Features in Anterior Canal BPPV-An Analysis of 13 Cases

Objective: To define diagnostic VNG features in anterior canal BPPV during positional testing (Dix-Hallpike, supine head hanging, and McClure Pagnini tests).

Study Design: A retrospective study of patients diagnosed with anterior canal BPPV across four referral centers in New Delhi, Kochi, Bangalore, and Dubai.

Subjects and Methods: Clinical records of 13 patients with AC BPPV out of 1,350 cases, during a 3-years period, were reviewed and analyzed by four specialists.

Results: Four patients had positional down beating nystagmus with symptoms of vertigo during the bilateral DHP maneuver. Seven cases had positional down beating nystagmus only on one side of DHP. Typical down beating nystagmus was seen in 10 out of 13 cases during the straight head hanging maneuver. Down beating torsional nystagmus was seen in 6 out of 13 cases. Down beating with horizontal nystagmus was seen in three cases (in DHP and MCP mainly) while pure down beating nystagmus during SHH was only seen in four cases.

Conclusion: We conclude that anterior canal BPPV is a rare but definite entity. It may not be apparent on positional testing the first time, so repeated testing may be needed. The most consistent diagnostic maneuver is SHH though there were patients in which findings could only be elicited using DHP testing. We recommend a testing protocol that includes DHP testing on both sides and SHH. MCP testing may also evoke DBN with or without the torsional component. Reversal of nystagmus on reversal of testing position is unusual but can occur. The Yacovino maneuver is effective in resolving AC BPPV. We also propose a hypothesis that explains why DHP testing is sensitive to AC BPPV on either side, whereas MCP lateral position on one side is only sensitive to AC BPPV on one side. We have explained a possible role for the McClure Pagnini test in side determination and therapeutic implications.

Estimated Vestibulogram (EVEST) for Effective Vestibular Assessment

BACKGROUND

The availability and development of methods testing the vestibuloocular reflex (VOR) brought a broader view into the lateral semicircular canal (L-SCC) function. However, the higher number of evaluated parameters makes more difficult the specialist's diagnose-making process.

PURPOSE

To provide medical specialists, a new diagnostic-graphic tool, Estimated Vestibulogram- EVEST, enabling a quick and easy-to-read visualization and comparison of the VOR test results within the L-SCC.

METHODS

The development of EVEST involved 148 participants, including 49 healthy volunteers (28 female and 21 male) and 99 (58 female and 41 male) patients affected by different degrees of peripheral vestibular deficit. The corresponding L-SCC VOR test results, from patients meeting the diagnostic criteria, were used to create the EVEST.

RESULTS

Based on the test results, we depicted and calculated the EVEST vestibular function asymmetry (VFA) in all the groups. To assess a feasibility of EVEST to describe a vestibular function deficit, we calculated sensitivity and specificity of VFA using a receiver operating characteristic curve (ROC) and compared it to single tests. In all the tests, we determined the cutoff value as the point with the highest sensitivity and specificity. For discrimination of any vestibular deficit, the VFA with cutoff 6.5% was more sensitive (91%) and specific (98%) than single tests. Results showed that EVEST is a beneficial graphic tool for quick multifrequency comparison and diagnosis of different types of the peripheral vestibular loss.

CONCLUSIONS

EVEST can help to easily evaluate various types of peripheral vestibular lesion.

Spontaneous Jamming of Horizontal Semicircular Canal Combined with Canalolithiasis of Contralateral Posterior Semicircular Canal

Spontaneous canalith jam is an uncommon form of benign paroxysmal positional vertigo mimicking acute vestibular neuritis. We described for the first time a spontaneous horizontal semicircular canalith jam associated with a typical canalolithiasis involving contralateral posterior semicircular canal (PSC), illustrating how the latter condition modified direction-fixed nystagmus during head movements. An 81-year-old woman with persistent vertigo referred to our center. Video-Frenzel examination showed horizontal direction-fixed right-beating nystagmus in primary gaze position, inhibited by visual fixation. She exhibited corrective saccades after leftward head impulses. Chin-to-chest positioning at the head-pitch test did not modify spontaneous nystagmus, whereas slight torsional components with the top pole of the eye beating toward the right ear appeared in backward head-bending, resulting in mixed horizontal-torsional nystagmus. At supine positioning tests, direction-fixed nystagmus turned into direction-changing geotropic horizontal nystagmus, which was stronger on the left side, while overlapping upbeat nystagmus with torsional right-beating components appeared on the right. Primary clinical findings were consistent with a left horizontal semicircular canalith jam, inducing a persistent utriculofugal cupular displacement, combined with a typical right-sided PSC-canalolithiasis. Once canalith jam crumbled, resulting in a non-ampullary arm canalolithiasis of the horizontal semicircular canal, both involved canals were freed by debris with appropriate repositioning procedures.

Unusual Vestibulo-Ocular Reflex Responses in Patients With Peripheral Vestibular Disorders Detected by the Caloric Step Stimulus Test

The caloric step stimulus test consists of the changes in head position from the sitting to supine positions and continuous caloric irrigation. This test can provide a single labyrinth with a stimulus similar to constant head acceleration in rotational testing and, therefore, can evaluate vestibulo-ocular reflex (VOR) dynamics more precisely than can conventional methods. To assess the clinical utility of the test in the assessment of the VOR dynamics of diseases, we performed the test in patients with peripheral vestibular disorders, including sudden idiopathic hearing loss, vestibular neuritis, Meniere disease, vestibular Meniere disease, or chronic unilateral idiopathic vestibulopathy and normal controls. Slow-phase eye velocity (SPV) was measured with videonystagmography. We fitted the time course of SPV across 2 min to a mathematical model containing two exponential components and time constants: the caloric step VOR time constant (T₁) and caloric step VOR adaptation time constant (T₂). All responses of normal controls (n = 15 ears) were fit to the model. Several responses of the 101 ears of the patients differed from the time courses predicted by the model. We divided the data of 116 ears into four patterns based on SPV, T₁, and T₂. The thresholds for the classification were determined according to the lower limits of the capability of curve fitting for SPV and the upper limits of normal controls for T₁ and T₂. Seventy-eight ears followed pattern A (normal T₁ and T₂): the SPV trajectory formed a rapid rise with subsequent decay. Nineteen followed pattern B (normal T₁ and prolonged T₂): the SPV trajectory formed a rapid rise without decay. Six followed pattern C (prolonged T₁ and T₂): the SPV trajectory formed a slow rise. Thirteen ears followed pattern D: a low VOR response. There were no significant differences in time constants between the affected and healthy ears in patients with each disease. However, prolonged T₁ and T₂ were significantly more frequent in the affected ears than the healthy ears. In conclusion, the caloric step stimulus test can be potentially useful in detecting unusual VOR responses and thus reflect some pathological changes in the vestibular system.

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.

Eye movement patterns in Iranian dyslexic children compared to non-dyslexic children

OBJECTIVE

Dyslexia is the most common learning disorder that affects 5-10% of school aged children. Eye movement abnormalities and visual processing deficits have been reported in some of dyslexic children. Objective of this study is to compare the eye-movement patterns of Iranian dyslexic children with those of non-dyslexic children as they perform the oculomotor tests and to explore the relationship between their eye-movement patterns and their reading ability.

METHODS

Binocular eye movements were recorded by oculomotor subtype of videonystagmography (VNG) testing on 30 dyslexic children and 20 non-dyslexic age-matched children (aged 8-12) in both genders. Dyslexic children were diagnosed with DSM-V scale by experts in reading disorder centers. Gain of the pursuit and optokinetic tests and the latency, accuracy and velocity of the saccade test were measured in both groups of dyslexic and non-dyslexic children. The independent samples t-test, Chi-square test and linear regression test in SPSS v. 21 were used to analyze behavioral and eye-movement parameters.

RESULTS

Compared to the non-dyslexic group, dyslexic children presented lower gain in pursuit and optokinetic tests, and increased latency with decreased accuracy in saccade test. All behavioral and eye-movement parameters without saccade velocity differed significantly among two groups.

CONCLUSION

The atypical eye movement patterns observed in dyslexic children suggests a deficiency in the visual information processing and an immaturity of brain structures responsible for oculomotor skills.

A novel maneuver for diagnosis and treatment of torsional-vertical down beating positioning nystagmus: anterior canal and apogeotropic posterior canal BPPV

Introduction

In patients with benign paroxysmal positional vertigo, BPPV; a torsional-vertical down beating positioning nystagmus can be elicited in the supine straight head-hanging position test or in the Dix-Hallpike test to either side. This type of nystagmus can be explained by either an anterior canal BPPV or by an apogeotropic variant of the contralateral posterior canal BPPV Until now all the therapeutic maneuvers that have been proposed address only one possibility, and without first performing a clear differential diagnosis between them.

Objective

To propose a new maneuver for torsional-vertical down beating positioning nystagmus with a clear lateralization that takes into account both possible diagnoses (anterior canal-BPPV and posterior canal-BPPV).

Methods

A prospective cohort study was conducted on 157 consecutive patients with BPPV. The new maneuver was performed only in those with torsional-vertical down beating positioning nystagmus with clear lateralization.

Results

Twenty patients (12.7%) were diagnosed with a torsional-vertical down beating positioning nystagmus. The maneuver was performed in 10 (6.35%) patients, in whom the affected side was clearly determined. Seven (4.45%) patients were diagnosed with an anterior canal-BPPV and successfully treated. Two (1.25%) patients were diagnosed with a posterior canal-BPPV and successfully treated with an Epley maneuver after its conversion into a geotropic posterior BPPV.

Conclusion

This new maneuver was found to be effective in resolving all the cases of torsional-vertical down beating positioning nystagmus-BPPV caused by an anterior canal-BPPV, and in shifting in a controlled way the posterior canal-BPPV cases of the contralateral side into a geotropic-posterior-BPPV successfully treated during the followup visit. Moreover, this new maneuver helped in the differential diagnosis between anterior canal-BPPV and a contralateral posterior canal-BPPV.

Congruous Torsional Down Beating Nystagmus in the Third Position of the Semont's Maneuver in Patients Treated for Canalithiasis of Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo: Its Significance and Prognostic Value

Due to its mechanical pathogenesis, benign paroxysmal positional vertigo treatment is mainly physical: when posterior semicircular canal is involved, Semont's maneuver is reported as one of the most effective liberating procedures. In the case of a canalolithiasis, the efficacy of the maneuver is corroborated by the appearance of some nystagmus findings during its performance. Liberating nystagmus, that can occur in the second position of Semont's maneuver and whose direction is congruous with the excitation of the affected posterior semicircular canal has proven to be a favorable prognostic sign. On the other hand, in clinical experience, we've frequently verified the appearance of another nystagmus during the execution of the maneuver: upon reaching the third position, when replacing the patient seated, a torsional down beating nystagmus, with the torsional component “congruous” with the stimulation of the vertical semicircular canals of the affected side, can often be appreciated. Such a sign can occur with or without having had the previous liberating nystagmus in the second position and is almost always associated with an intense vertigo and/or body pulsion. In this study, we describe the incidence and characteristics of the congruous torsional down beating nystagmus that can arise by assuming the third position of Semont's maneuver in a cohort of patients treated for posterior semicircular canal benign paroxysmal positional vertigo due to canalolithiasis. In the best of our knowledge, such a sign has never been described and explained before. On the basis of the pathophysiology and of the possible canal receptors stimulation during the different phases of Semont's maneuver, we formulated different hypothesis on how such a nystagmus can be generated. We observed that such a sign, when elicited, has a very good prognostic meaning for healing purposes, even better than that of liberating nystagmus. Therefore, congruous torsional down beating nystagmus should always be checked when performing Semont's maneuver because it could help in predicting success of physical treatment and in managing patients.

Vestibular and Ocular Motor Properties in Lateral Medullary Stroke Critically Depend on the Level of the Medullary Lesion

Background: Lateral medullary stroke (LMS) results in a characteristic pattern of brainstem signs including ocular motor and vestibular deficits. Thus, an impaired angular vestibulo-ocular reflex (aVOR) may be found if the vestibular nuclei are affected.

Objective: We aimed to characterize the frequency and pattern of vestibular and ocular-motor deficits in patients with LMS.

Methods: Patients with MR-confirmed acute/subacute unilateral LMS from a stroke registry were included and a bedside neuro-otological examination was performed. Video-oculography and video-based head-impulse testing (vHIT) was obtained and semicircular canal function was determined. The lesion location/extension as seen on MRI was rated and involvement of the vestibular nuclei was judged.

Results: Seventeen patients with LMS (age = 59.4 ± 14.3 years) were included. All patients had positive H.I.N.T.S. vHIT showed mild-to-moderate aVOR impairments in three patients (ipsilesional = 1; ipsilesional and contralesional = 1; contralesional = 1). Spontaneous nystagmus (n = 10/15 patients) was more often beating contralesionally than ipsilesionally (6 vs. 3) and was accompanied by upbeat nystagmus in four patients. Head-shaking nystagmus was noted in seven subjects, ipsilesionally beating in six and down-beating in one. On brain MRI, damage of the most caudal parts of the medial and/or inferior vestibular nucleus was noted in 13 patients. Only those two patients with lesions affecting the rostral medulla oblongata demonstrated an ipsilaterally impaired aVOR.

Conclusions: While subtle ocular motor signs pointed to damage of the central–vestibular pathways in all 17 patients, aVOR deficits were infrequent, restricted to those patients with rostral medullary lesions and, if present, mild to moderate only. This can be explained by lesions located too far caudally and too far ventrally to substantially affect the vestibular nuclei.

[The Bárány Classification of vestibular disorders, its clinical implementation and future prospects]

Vestibular diseases often have no or only nonspecific biomarkers. It is therefore necessary to define these disorders using operational criteria based on patterns of symptoms, i.e., the presence of inclusion and exclusion criteria, similar to the situation with headaches or psychiatric diseases. Ten years ago, the Bárány Society embarked upon development of the International Classification of Vestibular Disorders (ICVD). This entails producing the different definitions iteratively according to a structured procedure with an internal review process, resulting in an open-access publication on the diagnostic criteria in each case. It is a multidisciplinary effort, and depending on the topic, cooperation with other scientific societies is sought. The classification encompasses primary vestibular disorders and non-vestibular disorders that may manifest with prominent vestibular symptoms. The following paper describes the procedure and briefly presents definitions which have already been published as well as those presently in elaboration.

Hybrid clustering system using Nystagmus parameters discrimination for vestibular disorder diagnosis

BACKGROUD AND OBJECTIVE

The control of clinical manifestation of vestibular system relies on an optimal diagnosis. This study aims to develop and test a new automated diagnostic scheme for vestibular disorder recognition.

METHODS

In this study we stratify the Ellipse-fitting technique using the Video Nysta Gmographic (VNG) sequence to obtain the segmented pupil region. Furthermore, the proposed methodology enabled us to select the most optimum VNG features to effectively conduct quantitative evaluation of nystagmus signal. The proposed scheme using a multilayer neural network classifier (MNN) was tested using a dataset involving 98 patients affected by VD and 41 normal subjects.

RESULTS

The new MNN scheme uses only five temporal and frequency parameters selected out of initial thirteen parameters. The scheme generated results reached 94% of classification accuracy.

CONCLUSIONS

The developed expert system is promising in solving the problem of VNG analysis and achieving accurate results of vestibular disorder recognition or diagnosis comparing to other methods or classifiers.