Research in Vestibular Science

Volume 21 (4); December 2022

Original Articles

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.

The Head-Bending Test in Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo: Sol-lim Choi, Hyun-Sung Kim, Jae-Hwan Choi, Eun Hye Oh; Res Vestib Sci. 2022;21(4):99-103. Published online December 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.4.99

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Abstract PDF: Objectives
This study aimed to investigate clinical significance of a head-bending test in benign paroxysmal positional vertigo (BPPV) involving the posterior semicircular canal (PC-BPPV).
Methods
We retrospectively recruited 256 patients with unilateral PC-BPPV between January 2016 and December 2021, and assessed the clinical characteristics of patients showing head-bending nystagmus (HBN).
Results
Of 256 patients, 138 (53.9%) showed HBN. Most patients (n=136, 98.6%) had downbeat nystagmus with (n=38) or without (n=98) torsional component. The remaining two patients had pure upbeat and torsional nystagmus, respectively. The torsional component was directed to the contralesional side in all. Between patients with and without HBN, there were no significant differences in clinical characteristics such as age, lateralization, types of BPPV (canalolithiasis or cupulolithiasis), and success rate of repositioning maneuver.
Conclusions
Head-bending test may be useful in predicting the diagnosis and lateralization of PC-BPPV.

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.

Video

A Case of Vertebral Artery Compression Syndrome Showing Characteristic Nystagmus during Head Rotation: Eun-Ju Jeon; Res Vestib Sci. 2022;21(4):111-112. Published online December 15, 2022; DOI: https://doi.org/10.21790/rvs.2022.21.4.111

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