Paradigm shift in acute dizziness: is caloric testing obsolete?

Nationwide Prevalence of Video Head Impulse Test Abnormality and its Risk Factors in South Korea

OBJECTIVE

To identify the prevalence of and relevant information for video head impulse test (vHIT) abnormality in a large population.

STUDY DESIGN

A cross-sectional design.

SETTING

Korean National Health and Nutrition Examination Survey, 2021.

METHODS

The sample was representative of the Korean population, with 2237 participants aged ≥40 years. A vHIT was performed to evaluate vestibular function. The vestibulo-ocular reflex (VOR) gain and the presence of reproducible catch-up saccades was assessed in a vHIT. Participants also completed questionnaires for demographics, socioeconomic status, and basic information regarding systemic diseases and dizziness and underwent hearing tests with automated pure-tone audiometry.

RESULTS

The prevalence of vHIT abnormality was 22.5%, with unilateral (14.3%) being more common than bilateral (8.2%). The prevalence of vHIT abnormality increased significantly with age, with the highest rate observed in individuals aged >70 years (42.5%). Both hearing and VOR gain deteriorated with age, but the patterns of age-related progression were different. While hearing loss (HL) deteriorated gradually and progressively throughout adulthood, VOR gain deterioration was markedly evident after 70 years of age.

CONCLUSION

Considering the high prevalence of vHIT abnormality, appropriate social and medical policies are needed to prevent associated injuries and improve patients' quality of life. The distinct age-related changes in HL and objective findings of vestibular dysfunction indicate the need for different approaches to address these social problems in aging countries.

Video head impulse test in subacute and chronic stroke survivors: new perspectives for implementation of assessment in rehabilitation

INTRODUCTION

The Video Head Impulse Test (vHIT) is a safe and reliable assessment of peripheral vestibular function. Many studies tested its accuracy in clinical settings for differential diagnosis and quantification of the vestibulo-oculomotor reflex (VOR) in various disorders. However, the results of its application after lesions of the CNS are discordant and have never been studied in rehabilitation. This study aims to assess the VOR performance in a sample of stroke survivors.

METHODS

This is a cross-sectional study on 36 subacute and chronic stroke survivors; only persons with first-ever stroke and able to walk independently, even with supervision, were included. We performed VOR assessments for each semicircular canal by vHIT and balance assessments by the Berg Balance Scale and the MiniBESTest scale.

RESULTS

Two hundred and sixteen semicircular canals were assessed using the Head Impulse paradigm (in both the vertical and horizontal planes), while 72 semicircular canals were assessed using the Suppressed Head Impulse paradigm (horizontal plane). There was a high prevalence of participants with dysfunctional canals, particularly for the left anterior and right posterior canals, which were each prevalent in more than one-third of our sample. Furthermore, 16 persons showed an isolated canal dysfunction. The mean VOR gain for the vertical canals had confidence intervals out of the normal values (0.74-0.91 right anterior; 0.74-0.82 right posterior; 0.73-0.87 left anterior).

CONCLUSION

Our findings suggest that peripheral vestibular function may be impaired in people with stroke; a systematic assessment in a rehabilitation setting could allow a more personalized and patient-centred approach.

Video head impulse test in stroke: a review of published studies

Accurate and timely diagnosis of posterior circulation stroke in patients with acute dizziness is a challenge that can lead to misdiagnosis and significant harm. The present review sought to identify and describe published research on the clinical application of vHIT in posterior circulation stroke. vHIT, a portable device, has gained prominence in evaluating peripheral vestibular disorders and offers potential applications in diagnosing neurological disorders, particularly posterior circulation stroke. Several studies have shown that vHIT can differentiate between stroke and vestibular neuritis based on VOR gain values, with high sensitivity and specificity. The manuscript also discusses vHIT's performance in differentiating between types of posterior circulation stroke, such as PICA, AICA, and SCA strokes. While vHIT has demonstrated promise, the review emphasizes the need for further research to validate its use as a tool to rule out stroke in acute dizziness patients in the emergency department. In conclusion, the manuscript underscores the potential of vHIT as a valuable addition to the diagnostic arsenal for acute dizziness, particularly in the context of posterior circulation stroke. It calls for further research and wider adoption of vHIT in clinical settings to improve patient care and reduce unnecessary costs associated with misdiagnoses.

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.

Comparative utility of vestibular function tests in patients with peripheral and central vestibular dysfunction

Background

Bithermal caloric irrigation, video head impulse test (vHIT), and rotational testing are commonly used to assess peripheral vestibular function, but the relative clinical utility of each test in differentiating patients with peripheral vestibulopathy is debated.

Objectives

To determine whether (1) the combination of two or more vestibular tests enhances diagnostic utility over a single test; (2) abnormal test results on vestibular tests correlate with one another.

Methods

Retrospective analysis of data collected from multidisciplinary vestibular clinics at two academic medical centers from 2016 to 2022.

Results

150 patients (54.10 ± 15.09 years, 88 females) were included. No individual test was significantly better at predicting the presence of peripheral vestibular damage (p > 0.05). vHIT test results improved significantly when combined with either the caloric test (p = 0.007) or rotary chair test (p = 0.039). Caloric and rotational testing had high sensitivity (74.65% and 76.06%, respectively) and specificity (83.54% and 78.48%, respectively). vHIT demonstrated excellent specificity (89.87%) but poor sensitivity (47.89%). Caloric, vHIT, and rotary chair tests results did not correlate with one another (p > 0.05).

Conclusions

Vestibular function tests have comparable diagnostic utility, yet each offers unique advantages. Caloric and rotational testing may be best suited for screening peripheral damage and vHIT may function ideally as a confirmatory test.

Do monosymptomatic stroke patients with dizziness present a vestibular syndrome without nystagmus? An underestimated entity

BACKGROUND AND PURPOSE

Vestibular symptoms are common in emergency department (ED) patients and have various causes, including stroke. Accurate identification of stroke in patients with vestibular symptoms is crucial for timely management. We conducted a prospective cross-sectional study from 2015 to 2019 to determine stroke prevalence and associated symptoms in ED patients with vestibular symptoms, aiming to improve diagnosis and outcomes.

METHODS

As part of the DETECT project, we screened 1647 ED patients with acute vestibular symptoms. Following a retrospective analysis of 961 head and neck magnetic resonance imaging (MRI) scans, we included 122 confirmed stroke cases and assessed them for vestibular signs and symptoms.

RESULTS

Stroke prevalence in dizzy patients was 13% (122/961 MRI scans). Most patients (95%) presented with acute vestibular symptoms with or without nystagmus, whereas 5% had episodic vestibular syndrome (EVS). Nystagmus was present in 50% of stroke patients. Eighty percent had a purely posterior circulation stroke, and nystagmus was absent in 46% of these patients. Seven patients (6%) had lesions in both the anterior and posterior circulation. Vertigo was experienced by 52% regardless of territory.

CONCLUSIONS

A stroke was identified in 13% of ED patients presenting with acute vestibular symptoms. In 5%, it was EVS. Most strokes were in the posterior circulation territory; vertigo occurred with similar frequency in anterior and posterior circulation stroke, and absence of nystagmus was common in both.

Vestibular syndromes, diagnosis and diagnostic errors in patients with dizziness presenting to the emergency department: a cross-sectional study

OBJECTIVES

We aimed to determine the frequency of vestibular syndromes, diagnoses, diagnostic errors and resources used in patients with dizziness in the emergency department (ED).

DESIGN

Retrospective cross-sectional study.

SETTING

Tertiary referral hospital.

PARTICIPANTS

Adult patients presenting with dizziness.

PRIMARY AND SECONDARY OUTCOME MEASURES

We collected clinical data from the initial ED report from July 2015 to August 2020 and compared them with the follow-up report if available. We calculated the prevalence of vestibular syndromes and stroke prevalence in patients with dizziness. Vestibular syndromes are differentiated in acute (AVS) (eg, stroke, vestibular neuritis), episodic (EVS) (eg, benign paroxysmal positional vertigo, transient ischaemic attack) and chronic (CVS) (eg, persistent postural-perceptual dizziness) vestibular syndrome. We reported the rate of diagnostic errors using the follow-up diagnosis as the reference standard.

RESULTS

We included 1535 patients with dizziness. 19.7% (303) of the patients presented with AVS, 34.7% (533) with EVS, 4.6% (71) with CVS and 40.9% (628) with no or unclassifiable vestibular syndrome. The three most frequent diagnoses were stroke/minor stroke (10.1%, 155), benign paroxysmal positional vertigo (9.8%, 150) and vestibular neuritis (9.6%, 148). Among patients with AVS, 25.4% (77) had stroke. The cause of the dizziness remained unknown in 45.0% (692) and 18.0% received a false diagnosis. There was a follow-up in 662 cases (43.1%) and 58.2% with an initially unknown diagnoses received a final diagnosis. Overall, 69.9% of all 1535 patients with dizziness received neuroimaging (MRI 58.2%, CT 11.6%) in the ED.

CONCLUSIONS

One-fourth of patients with dizziness in the ED presented with AVS with a high prevalence (10%) of vestibular strokes. EVS was more frequent; however, the rate of undiagnosed patients with dizziness and the number of patients receiving neuroimaging were high. Almost half of them still remained without diagnosis and among those diagnosed were often misclassified. Many unclear cases of vertigo could be diagnostically clarified after a follow-up visit.

The role of vestibular cold caloric tests in the presence of spontaneous nystagmus

Objective

The bithermal caloric test is commonly used to detect a canal paresis. However, in case of spontaneous nystagmus, this procedure can provide results of non-univocal interpretation. On the other hand, confirming the presence of a unilateral vestibular deficit can help to differentiate between central and a peripheral vestibular involvement.

Methods

We studied 78 patients suffering from acute vertigo and showing spontaneous horizontal unidirectional nystagmus. All patients were submitted to bithermal caloric tests, and the results were compared with those obtained using a monothermal (cold) caloric test.

Results

We demonstrate the congruence between the bithermal and monothermal (cold) caloric test through mathematical analysis of the results of both tests in patients with acute vertigo and spontaneous nystagmus.

Conclusions

We propose to perform the caloric test in the presence of a spontaneous nystagmus using a monothermal cold assuming that the prevalence of the response to the cold irrigation on the side towards which the nystagmus beats is a sign of the presence of pathological unilateral weakness and therefore more likely peripheral in its origin.

Diagnostic accuracy of the physical examination in emergency department patients with acute vertigo or dizziness: A systematic review and meta-analysis for GRACE-3

BACKGROUND

History and physical examination are key features to narrow the differential diagnosis of central versus peripheral causes in patients presenting with acute vertigo. We conducted a systematic review and meta-analysis of the diagnostic test accuracy of physical examination findings.

METHODS

This study involved a patient-intervention-control-outcome (PICO) question: (P) adult ED patients with vertigo/dizziness; (I) presence/absence of specific physical examination findings; and (O) central (ischemic stroke, hemorrhage, others) versus peripheral etiology. Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) was assessed.

RESULTS

From 6309 titles, 460 articles were retrieved, and 43 met the inclusion criteria: general neurologic examination-five studies, 869 patients, pooled sensitivity 46.8% (95% confidence interval [CI] 32.3%-61.9%, moderate certainty) and specificity 92.8% (95% CI 75.7%-98.1%, low certainty); limb weakness/hemiparesis-four studies, 893 patients, sensitivity 11.4% (95% CI 5.1%-23.6%, high) and specificity 98.5% (95% CI 97.1%-99.2%, high); truncal/gait ataxia-10 studies, 1810 patients (increasing severity of truncal ataxia had an increasing sensitivity for central etiology, sensitivity 69.7% [43.3%-87.9%, low] and specificity 83.7% [95% CI 52.1%-96.0%, low]); dysmetria signs-four studies, 1135 patients, sensitivity 24.6% (95% CI 15.6%-36.5%, high) and specificity 97.8% (94.4%-99.2%, high); head impulse test (HIT)-17 studies, 1366 patients, sensitivity 76.8% (64.4%-85.8%, low) and specificity 89.1% (95% CI 75.8%-95.6%, moderate); spontaneous nystagmus-six studies, 621 patients, sensitivity 52.3% (29.8%-74.0%, moderate) and specificity 42.0% (95% CI 15.5%-74.1%, moderate); nystagmus type-16 studies, 1366 patients (bidirectional, vertical, direction changing, or pure torsional nystagmus are consistent with a central cause of vertigo, sensitivity 50.7% [95% CI 41.1%-60.2%, moderate] and specificity 98.5% [95% CI 91.7%-99.7%, moderate]); test of skew-15 studies, 1150 patients (skew deviation is abnormal and consistent with central etiology, sensitivity was 23.7% [95% CI 15%-35.4%, moderate] and specificity 97.6% [95% CI 96%-98.6%, moderate]); HINTS (head impulse, nystagmus, test of skew)-14 studies, 1781 patients, sensitivity 92.9% (95% CI 79.1%-97.9%, high) and specificity 83.4% (95% CI 69.6%-91.7%, moderate); and HINTS+ (HINTS with hearing component)-five studies, 342 patients, sensitivity 99.0% (95% CI 73.6%-100%, high) and specificity 84.8% (95% CI 70.1%-93.0%, high).

CONCLUSIONS

Most neurologic examination findings have low sensitivity and high specificity for a central cause in patients with acute vertigo or dizziness. In acute vestibular syndrome (monophasic, continuous, persistent dizziness), HINTS and HINTS+ have high sensitivity when performed by trained clinicians.

Artificial intelligence for early stroke diagnosis in acute vestibular syndrome

Objective

Measuring the Vestibular-Ocular-Reflex (VOR) gains with the video head impulse test (vHIT) allows for accurate discrimination between peripheral and central causes of acute vestibular syndrome (AVS). In this study, we sought to investigate whether the accuracy of artificial intelligence (AI) based vestibular stroke classification applied in unprocessed vHIT data is comparable to VOR gain classification.

Methods

We performed a prospective study from July 2015 until April 2020 on all patients presenting at the emergency department (ED) with signs of an AVS. The patients underwent vHIT followed by a delayed MRI, which served as a gold standard for stroke confirmation. The MRI ground truth labels were then applied to train a recurrent neural network (long short-term memory architecture) that used eye- and head velocity time series extracted from the vHIT examinations.

Results

We assessed 57 AVS patients, 39 acute unilateral vestibulopathy patients (AUVP) and 18 stroke patients. The overall sensitivity, specificity and accuracy for detecting stroke with a VOR gain cut-off of 0.57 was 88.8, 92.3, and 91.2%, respectively. The trained neural network was able to classify strokes with a sensitivity of 87.7%, a specificity of 88.4%, and an accuracy of 87.9% based on the unprocessed vHIT data. The accuracy of these two methods was not significantly different (p = 0.09).

Conclusion

AI can accurately diagnose a vestibular stroke by using unprocessed vHIT time series. The quantification of eye- and head movements with the use of machine learning and AI can serve in the future for an automated diagnosis in ED patients with acute dizziness. The application of different neural network architectures can potentially further improve performance and enable direct inference from raw video recordings.

Effects of Betahistine on Vestibulo-Ocular Reflex in Normal Healthy Adults: A Randomized Double-Blind, Placebo-Controlled Trial

Introduction

Vertigo, or the perception of a spinning sensation, is a common symptom experienced by patients who are referred to Otorhinolaryngology clinics. Betahistine is a medication that has been widely used to treat vertigo and its accompanying symptoms. However, the effects of this medication on the vestibulo-ocular reflex (VOR) are still unknown. Initially, it was assumed that betahistine should be discontinued prior to any vestibular tests, particularly the video head impulse test (vHIT).

Method

Thirty young healthy adults were randomly divided into two equal groups for this randomized double-blind clinical study (betahistine 24 mg and placebo). Baseline pure-tone audiometry (PTA), tympanometry, and VOR measurements were taken, followed by experimental measurements at one hour, four hours, eight hours, and 24 hours after consumption. The video head impulse test (vHIT) was used to determine the VOR.

Result

Betahistine had no statistically significant effect on vestibulo-ocular reflex gain (F(4,140) = 0.601, p = 0.662). The gain variability across repetitive head impulses remained constant over time.

Conclusions

Betahistine has no effect on the vestibulo-ocular reflex. As a result, this medication can be taken prior to the vHIT procedure.

Comparison between caloric and video-head impulse tests in Ménière's disease and vestibular neuritis

OBJECTIVE

To compare the diagnostic accuracies of air caloric testing with electronystagmography and the vHIT (video-head impulse test).

DESIGN

Prospective, controlled study.

STUDY SAMPLE

MD (Ménière's disease), 26; vestibular neuritis, 27; control, 56.

RESULTS

In MD, CP (canal paresis) was pathological in 88.5%, the GA (gain asymmetry) on vHIT was pathological in 65.3%, and the gain was abnormal in only one patient. The GA and CP, were significantly higher in the MD group than in the control group, indicating hypofunction of the horizontal canals in MD, whereas a hyperfunction may also occur. No correlation was observed between the results of the two tests for evaluating MD, suggesting that pathological outcomes of one test do not guarantee abnormalities on the other test. For vestibular neuritis, significantly higher CP (96.3%), GA (81.5%), and gain (51.9%) values were detected. A correlation was identified between the two tests for vestibular neuritis, indicating a similar diagnostic efficiency. The higher percentage of pathological GA versus pathological gain values indicates that the asymmetry may be more informative.

CONCLUSIONS

The vHIT showed a higher specificity, whereas the caloric test a higher sensitivity. No correlation between the two methods was observed; therefore, the tests appear to provide complementary information.

Current concepts in acute vestibular syndrome and video-oculography

PURPOSE OF REVIEW

We present here neuro-otological tests using portable video-oculography (VOG) and strategies assisting physicians in the process of decision making beyond the classical 'HINTS' testing battery at the bedside.

RECENT FINDINGS

Patients with acute vestibular syndrome (AVS) experience dizziness, gait unsteadiness and nausea/vomiting. A variety of causes can lead to this condition, including strokes. These patients cannot be adequately identified with the conventional approach by stratifying based on risk factors and symptom type. In addition to bedside methods such as HINTS and HINTS plus, quantitative methods for recording eye movements using VOG can augment the ability to diagnose and localize the lesion. In particular, the ability to identify and quantify the head impulse test (VOR gain, saccade metrics), nystagmus characteristics (waveform, beating direction and intensity), skew deviation, audiometry and lateropulsion expands our diagnostic capabilities. In addition to telemedicine, algorithms and artificial intelligence can be used to support emergency physicians and nonexperts in the future.

SUMMARY

VOG, telemedicine and artificial intelligence may assist physicians in the diagnostic process of AVS patients.

Machine learning method intervention: Determine proper screening tests for vestibular disorders

OBJECTIVE

To evaluate the performance of different vestibular indicators in disease classification based on machine learning method.

METHODS

This study use retrospective analysis of the vertigo outpatient database from a tertiary care general hospital. 1491 patients with definite clinical diagnoses were enrolled in this study. Spontaneous nystagmus, head-shaking nystagmus, positional nystagmus, unilateral weakness in caloric test, and gain and saccade in video head impulse test (vHIT) were recorded as variables. Diagnoses were mainly reorganized as acute vestibular syndrome, episodic vestibular syndrome, and chronic vestibular syndrome. The trained random forest model was applied based on exploratory data analysis results.

RESULTS

Random forest accuracies on acute, episodic, and chronic vestibular syndrome are 90%, 81.74%, and 91.3%, respectively. The most important features in acute vestibular syndrome are spontaneous nystagmus, and vHIT variables. In episodic vestibular syndrome, unilateral weakness in caloric test, gain and saccades on lateral semicircular canal are the top three parameters. Lateral vHIT gain, head-shaking nystagmus, and unilateral weakness in caloric test are the main parameters on chronic vestibular syndrome. In acute vestibular syndrome, spontaneous nystagmus and vHIT make major contributions in vestibular disorders distinction. When the disease course prolongation, unilateral weakness and head-shaking nystagmus become increasingly important.

CONCLUSION

Fast clinical test sets including spontaneous nystagmus, head shaking nystagmus, and vHIT should be the first consideration in screening vestibular disorders.