Research in Vestibular Science

Original Articles

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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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

The Clinical Efficacy of Vestibular Function Tests in Patients with Acute Unilateral Vestibulopathy: Bong-Hui Kang, Jae-Il Kim; Res Vestib Sci. 2018;17(2):49-54. Published online June 15, 2018; DOI: https://doi.org/10.21790/rvs.2018.17.2.49

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Abstract PDF: Objectives
Aim of this study is to investigate the clinical efficacy of the vestibular function tests (VFTs) and the predictability of lesion side of vestibular asymmetry parameters in acute unilateral peripheral vestibulopathy.
Methods
Medical records and results of VFTs (caloric, rotatory chair, and head impulse tests) of 57 patients with acute unilateral vestibulopathy were reviewed retrospectively. The VFTs were examined within 7 days after the clinical onset.
Results
For the caloric test, 74% showed significant canal paresis and the predictability of lesion side was 88%. For the sinusoidal harmonic acceleration test, 91% had low gain in at least 1 Hz, phase lead showed 70%, 89% showed phase asymmetry and the predictability of lesion side was 90%. For velocity step test, 67% had abnormal Tc asymmetry and the predictability of lesion side was 95%. In bedside head impulse test (HIT), abnormal catch up saccades were observed in 89% and the predictability of lesion side was 100%. For the video HIT, cover or overt catch-up saccades were observed in 95% and the predictability of lesion side was 100%. One hundred percent (100%) had low gain on the video HIT, but the lesion sides were uncertain because of bilateral involvements or artifacts.
Conclusions
The most important things in the diagnosis of acute unilateral vestibulopathy are typical clinical symptoms and spontaneous nystagmus. A combination of rotatory, caloric, and HITs will result in a more complete examination of the vestibular system. Among them, HIT is recommended as the best tool in acute unilateral vestibulopathy.

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