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.

Influence of Otoliths on the Vestibulo-Ocular Reflex in Horizontal Canal Benign Paroxysmal Positional Vertigo: Hee Soo Yoon, Jae Yeong Jeong, Jae Ho Chung, Ha Young Byun, Chul Won Park, Seung Hwan Lee; Res Vestib Sci. 2020;19(2):49-54. Published online June 15, 2020; DOI: https://doi.org/10.21790/rvs.2020.19.2.49

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Abstract PDF: Objectives
The aim of the study was to evaluate the possible alteration of the vestibulo-ocular reflex (VOR) in patients with horizontal canal benign paroxysmal positional vertigo (h-BPPV) using the video head impulse test (vHIT).
Methods
This was a prospective case-control study of BPPV patients. We includeed 133 patients with h-BPPV who underwent the vHIT prior to the positioning test. The control group consisted of 76 normal subjects who also underwent the vHIT. The vHIT parameters of gain and asymmetry were assessed, and clinical parameters such as treatment duration, number of canalith reposition maneuvers executed and recurrence rates were evaluated. The VOR and clinical parameters were compared between the h-BPPV and control group. The VOR parameters of h-BPPV canalolithiasis were also compared with those of cupulolithiasis.
Results
The mean age of the patients was 56.5 years and the male to female ratio was 1:2.02. Of the patients, 75 were diagnosed as having the canalolithiasis type of h-BPPV, while the other 58 had the cupulolithiasis type. The mean vHIT gains of the ipsi-lesional horizontal canal plane were 1.13 and 1.15 in the h-BPPV and control group, respectively (p=0.564). However, the asymmetry of the VOR was significantly higher in the h-BPPV than the control group (p=0.013), while the gains and asymmetries of the vHIT in the canalolith and cupulolith types were not significantly different (p=0.454, p=0.826).
Conclusions
The asymmetry of VOR is significantly elevated in the cupulolith type of hBPPV.

Can Cupulolithiasis Affect the Time Constant or Gain of the Velocity Step Test?: Min Tae Kim, Ji Eun Choi, Min Young Lee, Jae Yun Jung; Res Vestib Sci. 2019;18(4):98-102. Published online December 15, 2019; DOI: https://doi.org/10.21790/rvs.2019.18.4.98

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Abstract PDF

Objectives
The nystagmus evoked by an angular velocity step is influenced by the cupula dynamics and the status of velocity storage mechanisms. This study questioned whether the cupulolithiasis of horizontal canal benign paroxysmal positional vertigo (HC-BPPV) affects the time constant or gain of the velocity step test.
Methods
We performed a retrospective study of 30 patients who diagnosed with HC-BPPV and performed rotary chair test at Dankook University Hospital from June 2010 to May 2017. All patients had normal vestibular function on the sinusoidal harmonic acceleration test. According to the direction of nystagmus on the head roll test, we further divided the patients into “geotrophic” (canalolithiasis) and “apogeotrophic” (cupulolithiasis) groups. We compared the time constant (Tc), gain, and directional preponderance (DP) between the 2 groups. We also compared the time constant and gain between lesion side of BPPV and normal side in each group.
Results
In the supine head roll, geotrophic nystagmus observed in 14 patients and apogeotrophic nystagmus observed in 16 patients. When parameters of the velocity step test compared according to lesion side of BPPV (per-rotary of lesion side, postrotary of lesion side, per-rotary of normal side, and postrotary of normal side), there were no significant differences in Tc, gain, and DP between the 2 groups. There were also no significant differences in Tc and gain between lesion side and normal side in each group.
Conclusions
We assumed that cupulolithiasis of HC-BPPV could affect the cupular deflection evoked by an angular velocity step, but there were no significant differences in Tc and gain between patients with cupulolithiasis and canalolithiasis.

Citations

Citations to this article as recorded by

Influence of Otoliths on the Vestibulo-Ocular Reflex in Horizontal Canal Benign Paroxysmal Positional Vertigo
Hee Soo Yoon, Jae Yeong Jeong, Jae Ho Chung, Ha Young Byun, Chul Won Park, Seung Hwan Lee
Research in Vestibular Science.2020; 19(2): 49. CrossRef

Case Report

Arnold-Chiari Type 1 Malformation Mimicking Benign Paroxysmal Positional Vertigo: Young Chul Kim, Chae Dong Yim, Hyun Jin Lee, Dong Gu Hur, Seong Ki Ahn; Res Vestib Sci. 2019;18(3):87-90. Published online September 15, 2019; DOI: https://doi.org/10.21790/rvs.2019.18.3.87

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Abstract PDF: Arnold-Chiari malformation type 1 is a congenital disease characterized by herniation of the cerebellar tonsils through the foramen magnum. Most common clinical symptom is pain, including occipital headache and neck pain, upper limb pain exacerbated by physical activity or valsalva maneuvers. Various otoneurological manifestations also occur in patients with the disease, which has usually associated with dizziness, vomiting, dysphagia, poor hand coordination, unsteady gait, numbness. Patients with Arnold-Chiari malformation may develop vertigo after spending some time with their head inclined on their trunk. Positional and down-beating nystagmus are common forms of nystagmus in them. We experienced a 12-year-old female who presented complaining of vertigo related to changes in head position which was initially misdiagnosed as a benign paroxysmal positional vertigo.

Original Articles

Outcome of Canalith Repositioning Procedure in Patients with Persistent and Transient Geotropic Direction-Changing Positional Nystagmus: Short-term Follow-up Evaluation: Seung Sik Jeon, Sung Won Li, Sung Kyun Kim, Yong Bok Kim, Il-Seok Park, Seok Min Hong; Res Vestib Sci. 2018;17(3):109-115. Published online September 18, 2018; DOI: https://doi.org/10.21790/rvs.2018.17.3.109

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Abstract PDF: Objectives
Patients, who showed persistent geotropic-direction changing positional nystagmus (p-DCPN) tend to have different clinical manifestations from those who showed transient geotropic DCPN (t-DCPN). We investigated the clinical characteristics between p-DCPN and t-DCPN patients, and its recovery rate after canalith repositioning procedure (CRP).
Methods
Based on the duration of nystagmus, 117 geotropic DCPN patients were classified to 2 groups, p-DCPN and t-DCPN. Barbeque maneuver had been introduced towards the opposite direction of null plane for the p-DCPN patients, and to the opposite direction of stronger nystagmus for the t-DCPN patients.
Results
Seventy-four patients showed t-DCPN and 43 patients were classified to the p-DCPN cases. No p-DCPN patient showed prompt improvement after the 1st canalolith reposition therapy. Among the t-DCPN patients, 18 canal switch cases were found , but, there was no canal switch cases found among the p-DCPN The CRP has showed less effective for the p-DCPN patients than the t-DCPN patients (after the 1st CRP, 37 in 74 improved, p＜0.001).
Conclusions
Due to its distinguishing clinical manifestation, p-DCPN may have different pathogenesis and clinical mechanisms from t-DCPN. And for the p-DCPN patients, the CRP seems not an efficient treatment compared to the t-DCPN patients. Further study with larger number of enrolled subjects is necessary.

Dizzy and Psychological Scales in Benign Paroxysmal Positional Vertigo: Suspicious Patients without Characteristic Nystagmus: Seok Min Hong, Sung Kyun Kim, Heejin Kim, Seok Jin Hong, Yong Bok Kim, Il-Seok Park, Dawoon Oh; Res Vestib Sci. 2017;16(3):80-84. Published online September 15, 2017; DOI: https://doi.org/10.21790/rvs.2017.16.3.80

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Abstract PDF: Objectives
Patients, who have had a history of benign paroxysmal positional vertigo (BPPV)-like symptoms, but no characteristic nystagmus, were often present. They are diagnosed as having a resolved state from BPPV or normal, and tend to be overlooked. We investigated the dizzy and psychological scales in BPPV-suspicious patients. Methods: Thirty-nine patients, which they had vertigo of a short duration at the specific head position, and clinically suspicious BPPV, but no nystagmus in positional tests, were enrolled. We compared dizzy and psychological scales of suspicious BPPV patients with 138 BPPV patients, using dizziness handicap inventory (DHI), the beck depression inventory (BDI), and the Spielberger state-trait anxiety inventory. Additionally, among the BPPV-suspicious group, patients with a BPPV history were compared with those with no previous BPPV. Results: No differences in the all scales were found between the two groups. However, DHI scores of patients with a previous BPPV attack were significantly higher than those of patients with no BPPV-like symptoms; in particular, there was a significant difference in emotional scores. Conclusion: Although the patients had no characteristic nystagmus, if they have a BPPV-like history and symptoms, emotional support and periodic follow up are needed. In particular, careful observation should be performed in patients with previous BPPV attack.

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