Research in Vestibular Science

Original Articles

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.

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.

Case Reports

Dissociated Vertical-Torsional Nystagmus in Vestibular Nucleus Lesion: Hyun-Sung Kim, Eun Hye Oh, Jae-Hwan Choi; Res Vestib Sci. 2022;21(1):19-23. Published online March 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.1.19

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Abstract PDF: Dissociated vertical-torsional nystagmus is a unique form of nystagmus characterized by conjugate torsional but disparate vertical components. It has been mainly reported in internuclear ophthalmoplegia or medial medullary lesion involving the medial longitudinal fasciculus (MLF). The patterns of the nystagmus may be explained by a disruption of vestibulo-ocular reflex pathways from vertical semicircular canal or utriculo-ocular reflex within the MLF, but it is debatable. We described a dissociated upbeat-torsional nystagmus in a patient with vestibular nucleus infarction without involvement of MLF.

Isolated Floccular Infarction with Impairment of High-Frequency Vestibulo-Ocular Reflex: A Case Report: Eun Hye Oh, Hyun-Sung Kim, Jae-Hwan Choi; Res Vestib Sci. 2021;20(4):147-150. Published online December 15, 2021; DOI: https://doi.org/10.21790/rvs.2021.20.4.147

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Abstract PDF: The flocculus plays a crucial role in control of eye movements. Based on animal experiment, it is suggested that the flocculus is important for governing vestibuleocular reflexes. In humans, an isolated floccular lesion is extremely rare. We report oculomotor abnormalities in a patient with unilateral infarction of the flocculus, and compare our results with those of previously reported patients with floccular lesion.

Original Article

Analysis of Age-Dependent Normative Values of Suppression Video-Head-Impulse Test in Healthy Korean Subjects: Do Yoon Jeong, Yoon Sik Park, Sung Il Cho; Res Vestib Sci. 2019;18(1):8-13. Published online March 15, 2019; DOI: https://doi.org/10.21790/rvs.2019.18.1.8

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1 Crossref

Abstract PDF

Objectives
Suppression head impulse paradigm (SHIMP) in video head impulse test is now newly used to test vestibular function. The aim of this study was to analyze normative values of SHIMP for healthy Korean subjects in each decade of life.
Methods
SHIMP and HIMP responses were measured with the video head impulse test in 70 healthy subjects. Vestibulo-ocular reflex gain and anticompensatory saccade were analyzed and compared at each decade of life.
Results
All subjects produced anticompensatory saccades in SHIMP. Gain values did not vary significantly with age. Gain values in SHIMP were lower than gain values in HIMP. The gain values of rightward impulse were higher than the gain values of leftward impulse.
Conclusions
Gain values and anticompensatory saccades in SHIMP were consistently equal in each decade of life. Normative values of SHIMP seems largely unaffected by aging.

Citations

Citations to this article as recorded by

Normalization of the Suppression Head Impulse Test (SHIMP) and its correlation with the Head Impulse Test (HIMP) in healthy adults
Suheda Baran, Gulce Kirazli, Pelin Pistav Akmese, Nese Celebisoy, Tayfun Kirazli
Journal of Vestibular Research.2024; : 1. CrossRef

Case Report

Four Cases of Wernicke’s Encephalopathy with Impaired Horizontal Vestibular Ocular Reflexes: Hyuk-Su Jang, Byoung-Soo Shin, Man-Wook Seo, Sun-Young Oh; Res Vestib Sci. 2017;16(2):57-63. Published online June 15, 2017; DOI: https://doi.org/10.21790/rvs.2017.16.2.57

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Abstract PDF: Wernicke’s encephalopathy (WE) is a neurological disorder induced by a dietary vitamin B1 (thiamine) deficiency which is characterized by encephalopathy, gait ataxia, and variant ocular motor dysfunction. In addition to these classical signs of WE, a loss of the horizontal vestibulo-ocular reflex (VOR) is being reported as the major underdiagnosed symptoms in WE. In this retrospective single center study, we report four cases of WE initially presented with impaired horizontal VOR in addition to the classical clinical presentations, and imaging and neurotological laboratory findings were described.

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