Research in Vestibular Science

Original Articles

Unilateral Vestibulopathy Mimicking Inner Ear Ischemia Modeling Using Photothrombosis and Behavioral Assessment Using EthoVision: Min Seok Song, Min Young Lee, Ji Eun Choi, So-Young Chang, Jae-Hun Lee, John Patrick Cuenca, Nathaniel T. Carpena, Jae Yun Jung; Res Vestib Sci. 2023;22(4):112-119. Published online December 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.4.112

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Abstract PDF: Objectives
Inner ear ischemic animal models using photochemical reactions have been devised in various ways. Localized vascular ischemia occurs with 532-nm laser irradiation after systemic rose bengal injection, a known photothrombotic mechanism. The aim of this study is to evaluate a photothrombosis-induced vestibulopathy mimicking behavioral changes in the inner ear ischemia model.
Methods
Seven-week-old male Spraque-Dawley rats were used. Animals were divided into three groups: control group (n=6), sham laser group (n=9), and laser group (n=9). To induce the photothrombosis, animals were injected with rose bengal into the femoral vein and then were irradiated with a 532-nm laser (175 mW for 900 seconds) via transtympanic membrane. To investigate the vestibulopathy after photothrombosis, the behavior tests (tail lift reflex test, air righting reflex test, rotarod test) were performed on the 1st, 3rd, and 7th days after surgery. Additionally, an open field test was conducted and analyzed using EthoVision XT (Noldus).
Results
The laser group exhibited significant behavioral change to mimic vestibulopathy in all assessments. Inducing photothrombosis with rose bengal caused severe gait instability, which precluded rotarod testing. In the tail lift reflex test, the laser group displayed vestibular dysfunction with a lower angle formation compared to the control rats. During the open field test, the laser group exhibited reduced mobility, a condition that persisted in the laser groups for 7 days.
Conclusions
Noninvasive laser irradiation using rose bengal and a 532-nm laser induces photothrombosis in the inner ear of animals, leading to the development of vestibulopathy mimicking imbalanced behavior.

Efficacy of the Fixation Index of Bithermal Caloric Test for Differentiating Brain Lesions in Vestibular Disoder: Young Jae Lee, Wonyong Baek, Sung-Il Cho, Gi-Sung Nam; Res Vestib Sci. 2023;22(4):106-111. Published online December 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.4.106

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Abstract PDF: Objectives
This study was performed to investigate the efficacy of the fixation index (FI) of the bithermal caloric test for differentiating brain lesions in vestibular disorder.
Methods
We reviewed the medical records of 286 consecutive dizzy patients who underwent brain magnetic resonance imaging (MRI) and the bithermal caloric test at department of otorhinolarnygology. Central vestibulopathy (CVP) was defined as when corresponding lesion was identified on brain MRI, otherwise peripheral vestibulopathy (PVP) was defined. The FI was defined as the mean slow phase velocity (SPV) with fixation divided by the mean SPV without fixation, and failure was indicated when the FI exceeded 70%.
Results
The CVP confirmed by brain MRI and PVP were 16.8% and 83.2%, respectively. The most common CVPs were cerebellopontine angle tumor (n=19, 39.6%) and chronic cerebellar infarction (n=18, 37.5%). There were 23 cases of CVP (47.9%) and 47 cases of PVP (19.7%) with abnormal number of FI in at least two of the four caloric irrigations. The FI score of right cool (RC), left cool (LC), and right warm (RW) were also increased significantly in patients with CVP (p=0.031 at RCFI, p=0.014 at LCFI, p=0.047 at RWFI, and p=0.057 at LWFI; Mann-Whitney U-test).
Conclusions
If two or more abnormal FIs are detected during bithermal caloric testing, there is a high likelihood of CVP. Consequently, additional brain MRI may be necessary for further evaluation.

Case Reports

A Case of Patient with Bilateral Cochleovestibular Function Loss due to Infratentorial Superficial Siderosis: Gyuman Lee, Youngmin Mun, Dae Bo Shim; Res Vestib Sci. 2023;22(3):83-88. Published online September 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.3.83; Correction in: Res Vestib Sci 2023;22(4):137

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Abstract PDF: Superficial siderosis (SS) is a rare neurodegenerative condition characterized by hemosiderin deposition in the central nervous system, which sometimes leads to sensorineural hearing loss and vestibular dysfunction. This case report details the diagnosis and treatment of a 63-year-old female patient presenting with a yearlong history of postural instability and recent symptoms of sudden right-sided hearing loss and imbalance. Physical examination and imaging revealed bilateral deafness and infratentorial SS. Treatment, including medication, vestibular exercises, high-dose steroids, and hyperbaric oxygen therapy, led to a significant alleviation of dizziness but no improvement in hearing. This case emphasizes the need for clinicians to consider SS in patients presenting with sudden-onset hearing loss and dizziness, even without prior any medical history or trauma, to accurately identify the underlying cause.

A Case of Delayed Audiovestibulopathy after Posterior Circulation Ischemic Stroke: Hyun Su Lee, Eun Kyung Jeon, Dong Hwan Kwon, Tae Hoon Kong; Res Vestib Sci. 2023;22(3):77-82. Published online September 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.3.77

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Abstract PDF: Distinguishing central and peripheral causes of dizziness is vital. A case is presented where a 42-year-old man with a history of posterior circulation ischemic stroke developed acute unilateral vestibulopathy with hearing loss. Clinical examination revealed signs of vestibular dysfunction on the left side. Audiometry confirmed deafness on the left, but imaging ruled out new central issues. The patient was diagnosed with audiovestibulopathy and treated with steroids, antiviral agents, intratympanic injections, and hyperbaric oxygen therapy. Hearing loss persisted, but dizziness improved with vestibular rehabilitation. Poststroke patients should be closely monitored for peripheral complications. Further research should explore the benefits of antiplatelet therapy in vascular-related conditions, even without clear central lesions.

Original Article

Quantifying the Prevalence of Acute Vestibular Neuritis through Big Data Analysis: Chul Young Yoon, Seulgi Hong, Ji-Yun Park, Young Joon Seo; Res Vestib Sci. 2023;22(3):68-76. Published online September 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.3.68

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Abstract PDF Supplementary Material: Objectives
Big data analytics in healthcare research have gained momentum, offering unprecedented opportunities to investigate complex medical conditions like acute vestibular neuritis (AVN). However, an inappropriate definition can introduce bias and inaccuracies into prevalence estimation, making the results unreliable and hindering cross-study comparisons. The Health Insurance data in South Korea will be used to create a robust operational definition for AVN.
Methods
The study utilized the National Patients Sample dataset from the Health Insurance Review and Assessment Service (HIRA) of the Republic of Korea. The operational definition of AVN was defined using the HIRA data, which includes specific codes for diagnosis, testing, and medications. The revised categorization scheme for AVN was presented as case 1 through case 5, with criteria for each category.
Results
The optimal conditions are deemed to be those that encompass the outcomes of both case 5 and case 1-1, encompassing all conditions. The study also provided prevalence estimates for subgroups based on demographic factors (age, sex), and found a consistent pattern throughout all years, sex, and age.
Conclusions
The study analyzed the prevalence of AVN in case 1 and case 5, which were similar to the reference prevalence of 3.5 per 100,000 people reported in other countries. The study’s results are encouraging for several reasons, including the validity of the operational definitions used, and the agreement between the study’s prevalence estimates and the reference prevalence. The operational definition in statistics, in the context of big data, serves as a precise and standardized criterion.

Case Report

Acute Thiamine Deficiency Detected by Video Head Impulse Test in a Patient with Gastric Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma: Je-Woo Park, Jae-Myung Kim, Ji-Min Kim, Seung-Han Lee; Res Vestib Sci. 2023;22(2):52-56. Published online June 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.2.52

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Abstract PDF: Thiamine deficiency may cause Wernicke encephalopathy (WE) characterized by ataxia, ophthalmoplegia, and confusion. Aside from the triad of cardinal symptoms, selective or predominant impairments of bilateral horizontal canals may be observed in WE. Here, we report a patient with gastric mucosa-associated lymphoid tissue (MALT)-lymphoma complicated by an early stage of WE due to thiamine deficiency manifesting bilateral vestibular dysfunctions. A 78-year-old man recently diagnosed gastric MALT-lymphoma presented with dizziness and disequilibrium for several weeks. He showed mild imbalance while tandem walking and abnormal catch-up saccades bilaterally during bedside head impulse test (HIT). Video HIT revealed decreased vestibulo-ocular reflex gains with catch-up saccades for the bilateral horizontal and several vertical canals. Diagnostic work-up demonstrated decreased serum thiamine and lesions in the mammillary body and periaqueductal gray matter on brain magnetic resonance images. Furthermore, with thiamine replacement, his clinical symptoms were markedly improved. Also, vestibular symptoms and signs may be an early manifestation of WE, and video HIT could be a useful diagnostic tool to aid early detections.

Original Articles

A Comparative Analysis of the Vestibulocochlear Function in Patients with Isolated Semicircular Canal Hypofunction Using a Video Head Impulse Test: Yu Jung Park, Min Young Lee, Ji Eun Choi, Jae Yun Jung, Jung Hwa Bahng; Res Vestib Sci. 2023;22(2):34-45. Published online June 15, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.2.34

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Abstract PDF: Objectives
The objective of this study was to analyze vestibulocochlear function results in patients identified with isolated semicircular canal (SCC) hypofunction using the video head impulse test (vHIT).
Methods
A retrospective review was conducted on the clinical records of 123 patients diagnosed with isolated SCC hypofunction based on vHIT results. Among these patients, 72 had isolated posterior SCC (PSCC) hypofunction, 25 had isolated lateral SCC (LSCC) hypofunction, and 26 had isolated anterior SCC (ASCC) hypofunction. Descriptive analyses were performed on various vestibulocochlear tests including pure tone audiometry, sinusoidal harmonic acceleration (SHA), spontaneous nystagmus (SN), head-shaking nystagmus (HSN), caloric testing, and cervical vestibular evoked myogenic potential, with results analyzed separately for each SCC hypofunction group.
Results
The study found that 66.0% of the evaluated patients exhibited abnormal results in at least one vestibulocochlear function test. PSCC hypofunction patients showed a significantly higher incidence of hearing loss compared to ASCC and LSCC hypofunction patients. LSCC hypofunction patients exhibited higher rates of corrective saccade, phase asymmetry of SHA, and SN abnormalities compared to other SCC hypofunction patients. Additionally, the rates of corrective saccade and phase asymmetry of SHA were also higher in LSCC hypofunction patients. ASCC hypofunction patients demonstrated significantly higher rates of normal corrective saccade, phase lead of SHA, and SN.
Conclusions
The analysis of this study suggests that even in cases where vHIT indicates isolated SCC hypofunction, additional vestibulocochlear function tests should be conducted to identify any associated vestibulocochlear dysfunctions. This highlights the importance of comprehensive evaluation to accurately diagnose and manage patients with SCC hypofunction.

Dizziness in Patients with Vestibular Epilepsy: Wankiun Lee, Jae-Moon Kim; Res Vestib Sci. 2023;22(1):7-13. Published online March 13, 2023; DOI: https://doi.org/10.21790/rvs.2023.22.1.7

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Abstract PDF: Objectives
Vestibular epilepsy refers to epilepsy in which vertigo is the sole or main symptom of a seizure. However, epilepsy is rarely considered as a differential diagnosis in patients complaining of dizziness. Here, we reviewed ten cases of vestibular epilepsy and analyzed the dizziness complained by the patient.
Methods
In this study, the medical records of dizziness patients with epileptic discharges observed on electroencephalogram were retrospectively analyzed. Patients who had other obvious causes of dizziness, lacked a description of dizziness, or were not taking antiseizure medications were excluded. We finally recruited 10 patients, and investigated their dizziness characteristic, brain imaging tests, electroencephalograms, and blood test findings.
Results
Patients with vestibular epilepsy usually felt dizzy abruptly while not moving, and often complained of dizziness in the form of spinning around or becoming dazed. Dizziness was short, usually between a few seconds and a few minutes, and the frequency of occurrence was variable, so there was no consistent trend. There were no abnormal findings in blood tests. In brain imaging test, most patients did not show significant abnormalities. The electroencephalographic abnormalities of the patients were mainly observed in the temporal lobe, and the dizziness they complained of improved when they started taking antiseizure medications.
Conclusions
If a patient with dizziness complains of dizziness that occurs suddenly and lasts for a short time, early electroencephalogram should be considered to prevent the diagnosis of epilepsy from being overlooked or delayed.

Difference of Cervical Vestibular Evoked Myogenic Potentials between Bone-Conduction and Air-Conduction in Patients with Nonspecific Dizziness: Yong-Hwi An, Jung Ho Choi, Seung Yeon Jeon, Hyun Joon Shim; Res Vestib Sci. 2022;21(4):93-98. Published online December 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.4.93

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Abstract PDF: Objectives
This study was performed to evaluate the difference of the cervical vestibular evoked myogenic potentials (cVEMP) stimulated by bone-conduction (BC) and air-conduction (AC) in patients with nonspecific dizziness.
Methods
Twenty-eight dizzy patients (56 ears) and 15 subjects (30 ears) as normal control was enrolled. Responses of BC- and AC-cVEMP were recorded sequentially in both groups. cVEMP parameters including latencies, inter-latencies intervals, amplitudes, and interaural amplitude asymmetry were analyzed and compared.
Results
Among the patients with nonspecific dizziness, AC-cVEMP responses were clearly detected in all 56 ears while BC-cVEMP responses were detected in 32 ears (57.1%). Amplitudes of BC-cVEMP were significantly smaller than those of AC-cVEMP in all patients with BC-cVEMP response. There was no difference in latencies, inter-latencies intervals, and interaural amplitude asymmetry ratios between BC- and AC-cVEMP. There was no significant difference in BCand AC-cVEMP between the dizzy and control groups.
Conclusions
BC-cVEMP is not clinically useful in comparison to AC-cVEMP for the evaluation of nonspecific dizziness. An effective stimulation tool for BC is necessary to provoke more reliable responses of BC-cVEMP.

Development of An Algorithm for Slippage-Induced Motion Artifacts Reduction in Video-Nystagmography: Yerin Lee, Young Joon Seo, Sejung Yang; Res Vestib Sci. 2022;21(4):104-110. Published online December 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.4.104

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Abstract PDF: Objectives
The slippage of the video-nystagmography devices causes motion artifacts in the trajectory of the pupil and thus results in distortion in the nystagmus waveform. In this study, the moving average was proposed to reduce slippage-induced motion artifacts from the real-world data obtained in the field.
Methods
The dataset consists of an infrared video of positional tests performed on eight patients with a lateral semicircular canal benign paroxysmal positional vertigo. The trajectories of the pupil were obtained from the video with binarization, morphological operation, and elliptical fitting algorithm. The acquired data was observed and the section where the slippage occurred was labeled by an otolaryngologist. The moving average with windows of various lengths was calculated and subtracted from the original signal and evaluated to find the most adequate parameter to reduce the motion artifact.
Results
The period of nystagmus in the given data was found to be ranged from 0.01 to 4 seconds. The slippages that appeared in the data can be categorized into fast and slow slippages. The length, distance, and speed of trajectories in the slippage ranges were also measured to find the characteristics of the motion artifact in video-nystagmography data. The shape of the nystagmus waveform was preserved, and the motion artifacts were reduced in both types of slippages when the length of the window in moving average was set to 1 second.
Conclusions
The algorithm developed in this study is expected to minimize errors caused by slippage when developing a diagnostic algorithm that can assist clinicians.

Case Report

Vestibular Neuritis after COVID-19 Vaccination: So-Hyun Kim, Se Hwan Hwang; Res Vestib Sci. 2022;21(3):89-92. Published online September 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.3.89

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Abstract PDF: Coronavirus disease 2019 (COVID-19) spread rapidly and was declared a pandemic. In this situation, vaccination for COVID-19 is important and has been prompted in many countries. However, a number of adverse events have been reported for the Pfizer, Moderna, and AstraZeneca vaccines. Otolaryngologic adverse events after COVID-19 vaccination were reported, including several cases of sudden sensorineural hearing loss. Vestibular neuritis (VN) is an acute vestibular syndrome that causes acute and spontaneous vertigo due to unilateral vestibular deafferentiation, leading to nausea or vomiting and unsteadiness that can last from days to weeks. Neurotropism for the cochleovestibular nerve, immunoglobulin G mediated immune off-target reaction, and reactivation of latent viruses are hypothesized to be etiologies. Herein, the case of a 49-year-old female who developed VN after COVID-19 vaccination is presented. Although the association between VN and COVID-19 vaccination remains unclear, clinicians should be aware that VN may occur as an adverse event of COVID-19 vaccination.

Original Articles

Assessment of the Vestibuloocular Reflex in Patients with Unilateral Chronic Middle Ear Disease Using the Video Head Impulse Test: A Preliminary Study: Gi-Sung Nam, Wonyong Baek, Sung-Il Cho; Res Vestib Sci. 2022;21(3):80-85. Published online September 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.3.80

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Abstract PDF: Objectives
This study aims to investigate the usefulness of the video head impulse test (vHIT) as a method for evaluating vestibular function in patients with unilateral chronic middle ear disease.
Methods
Nineteen patients with various unilateral middle ear diseases including chronic otitis media (COM), COM with cholesteatoma, and adhesive otitis media successfully underwent preoperative vHIT. The gain of vestibuloocular reflex (VOR) and the presence of corrective saccades were compared between the affected ear and the healthy ear.
Results
A total of eight male and 11 female patients with a mean age of 43.1 years were included in this retrospective study. Twelve ears had COM, four had COM with cholesteatoma, and three had adhesive otitis media. A positive history of vertigo or dizziness was reported in 36.8% of the cases. The VOR gain of the affected ears and the healthy ears were 0.97±0.16 vs. 1.00±0.08 in the horizontal canal, 0.91±0.11 vs. 0.87±0.11 in the anterior canal, and 0.87±0.17 vs. 0.99±0.12 in the posterior canal, respectively. Only VOR gain of the posterior canal was significantly decreased compared with healthy ears.
Conclusions
The average VOR gains in the patients with chronic middle ear disease were within the pre-defined values of normality; however, when compared quantitatively, posterior canal gain of affected ears was significantly decreased compared to healthy ears. Our results can be explained by the anatomical proximity of the ampulla of the posterior canal and middle ear space.

Impairment of Vestibular Function in Patients with Vestibular Schwannoma According to the Presence of Dizziness: Youngjeong Lee, Se A Lee, Eek-Sung Lee, Tae-Kyeong Lee, Jong Dae Lee; Res Vestib Sci. 2022;21(3):75-79. Published online September 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.3.75

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Abstract PDF: Objectives
Vestibular schwannoma (VS) is a benign Schwann cell-derived slow growing tumor originating from the vestibular nerve. Here, we aimed to investigate the correlation between the presence of the dizziness symptoms and several vestibular function test results.
Methods
We analyzed 32 patients who diagnosed with VS from 2010 to 2021 in our hospital. Caloric test, cervical vestibular-evoked myogenic potential (cVEMP) test, and video head impulse test (vHIT) were analyzed.
Results
Age, sex, pure tone audiometry, and tumor size did not show any statistical significance according to the presence or absence of dizziness. There was also no association between the presence of dizziness symptom or dizziness type and the results of the caloric test, vHIT, and cVEMP test, respectively. However, patients with dizziness had a higher rate of tumors confined to the inner auditory canal than those without dizziness.
Conclusions
In this study, the rate of complaints of dizziness was higer in patients with intracanalicular VS. The diagnostic role of vestibulsr function tests in VS is limited. The dissociation of the results of caloric test, vHIT, and cVEMP test suggest that these test are complementary.

Review

Vestibular Migraine: A Recent Update on Diagnosis and Treatment: Young Seo Kim, Hak Seung Lee; Res Vestib Sci. 2022;21(3):67-74. Published online September 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.3.67

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Abstract PDF: Vestibular migraine (VM) is a variant of migraine resulting in vestibular symptoms in addition to symptoms typical of migraine. However, without a biomarker or a complete understanding of the pathophysiology, VM remains underrecognized and underdiagnosed. Therefore, the diagnosis of VM is still challenging. Meanwhile, VM should be clearly differentiated from other similar diseases. Here, we highlight these challenges, discuss common vestibular symptoms and clinical presentations in VM, and review the current aspects of its clinical diagnosis and evaluation. The concepts related to the treatment of VM are also discussed.

Original Article

Auto-Pattern Recognition for Diagnosis in Benign Paroxysmal Positional Vertigo Using Principal Component Analysis: A Preliminary Study: O-Hyeon Gwon, Tae Hoon Kong, Jaehong Key, Sejung Yang, Young Joon Seo; Res Vestib Sci. 2022;21(1):6-18. Published online March 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.1.6

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Abstract PDF

Objectives
The aim of this study was to develop a filtering algorithm for raw nystagmus images and a diagnostic assistive algorithm using a principal component analysis (PCA) to distinguish the different types of benign paroxysmal positional vertigo (BPPV).
Methods
Fifteen video clips of clinical data with typical nystagmus patterns of BPPV (13 cases) and with normal nystamgmus (two cases) were preprocessed when applied the thresholding, morphology operation, residual noise filtering, and center point extraction stages. We analyzed multiple data clusters in a single frame via a PCA; in addition, we statistically analyzed the horizontal and vertical components of the main vector among the multiple data clusters in the canalolithiasis of the lateral semicircular canal (LSCC) and the posterior semicircular canal (PSCC).
Results
We obtained a clear imaginary pupil and data on the fast phases and slow phases after preprocessing the images. For a normal patient, a round shape of clustered dots was observed. Patients with LSCC showed an elongated horizontal shape, whereas patients with PSCC showed an oval shape at the (x, y) coordinates. The scalar values (mm) of the horizontal component of the main vector when performing a PCA between the LSCC- and PSCC-BPPV were substantially different (102.08±20.11 vs. 32.36±12.52 mm, respectively; p=0.0012). Additionally, the salar ratio of horizontal to vertical components in LSCC and PSCC exhibited a significant difference (16.11±10.74 mm vs. 2.61±1.07 mm, respectively; p=0.0023).
Conclusions
The data of a white simulated imaginary pupil without any background noise can be a separate monitoring option, which can aid clinicians in determining the types of BPPV exhibited. Therefore, this analysis algorithm will provide assistive information for diagnosis of BPPV to clinicians.

Citations

Citations to this article as recorded by

Development of An Algorithm for Slippage-Induced Motion Artifacts Reduction in Video-Nystagmography
Yerin Lee, Young Joon Seo, Sejung Yang
Research in Vestibular Science.2022; 21(4): 104. CrossRef

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