Research in Vestibular Science

Original Articles

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.

Temporal Relationship between Nystagmus and Perception during Bithermal Alternate Caloric Test: Sooyoung Kim, Eun-Jin Kwon, Hyunjin Jo, Seong-Hae Jeong; Res Vestib Sci. 2021;20(4):134-140. Published online December 15, 2021; DOI: https://doi.org/10.21790/rvs.2021.20.4.134

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Abstract PDF: Objectives
During caloric irritation, the spinning/rotating sensation is predominant. However, there is no report on the temporal relationship between caloric nystagmus and perception.
Methods
Consecutive 57 participants underwent bithermal caloric test in the dizziness clinic of Chungnam National University Hospital from February 2018 to September 2018. For vestibular perception, we asked the subject to report feelings of rotation and/or linear sensation during each warm and cold water irrigation period. Besides routine caloric parameters, the duration of nystagmus and vestibular sensation were analyzed.
Results
In most participants, the caloric nystagmus preceded the vestibular sensation (79.6% in right warm, 83.3% in left warm, 88.5% in right cool, and 84.6% in left cool stimuli). The precedence of perception was observed in 5 normal persons and 15 patients with vestibular migraine (n=4), unilateral vestibulopathy (n=3), and Menière’s disease (n=2), multiple systemic atrophy (n=2), cerebellar ataxia (n=2), vertebrobasilar insufficiency (n=1), and post-earthquake dizziness (n=1). The mean latency between nystagmus and perception was 11.7 seconds. And the duration of nystagmus was longer than that of perception in all conditions. Non-spinning sensations during the caloric test were also observed in some participants (26.8% in right warm, 30.3% in left warm, 29.1% in right cool, and 24.1% in left cool stimuli).
Conclusions
During the bithemal alternate caloric test, various vestibular perception and temporal relationship between perception and nystagmus suggest the bithermal caloric stimulation does not reflect only the signal originating from the horizontal canal pathway. A further validation study is needed.

Analysis of Clinical Features in Patients Showing Bilateral Vestibulopathy with Vestibular Function Test: Dong Hyun Kim, Jeong Hyun Lee, Bong Jik Kim, Chung Ku Rhee, Jae Yun Jung; Res Vestib Sci. 2014;13(2):47-52.

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Abstract PDF: Background and Objectives: Caloric test and rotatory chair test have been adopted in diagnosing bilateral vestibulopathy. However, most of patients who were confirmed by the diagnostic testing not complained typical symptoms of bilateral vestibulopathy such as ossilopsia and ataxia. Patients who do not have typical symptoms of bilateral vestibulopathy, were often diagnosed with bilateral vestibulopathy by caloric test and slow harmonic acceleration test (SHA). The aim of this study is to assess the clinical features between groups classified according to the caloric test and SHA test, and possibly to investigate the representative test in the diagnosis of bilateral vestibulopathy. Materials and Methods: Seventy-five patients were divided into three groups: (A) patients diagnosed with the caloric test only, (B) patients diagnosed with SHA test only, (C) patients satisfying the diagnostic criteria of both tests. Clinical characteristics, the results of physical examination, hearing test and vestibular function test (VFT) were compared among three groups. Results: There was no difference in clinical characteristics and results of physical examination among three groups. Regarding VFT results, only in step velocity test, The proportion of patients who showed low gain value on both sides were higher in group C than that of group A and B. No difference was observed in the other VFT results among three groups. Conclusion: We could not predict the clinical features of bilateral vestibulopathy by the results of VFT, and could not find preferable test in diagnosing bilateral vestibulopathy.

Results of High-Frequency and High-Acceleration Rotary Chair Test in Patients with Acute Unilateral Vestibular Neuritis: Hwan Seo Lee, Jun Woo Park, Chang Wook Lee, Chan Il Song, Myung Hoon Yoo, Hong Ju Park; Res Vestib Sci. 2014;13(2):41-46.

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Abstract PDF: r neuritis. Materials and Methods: Twenty-four patients who were diagnosed as acute vestibular neuritis and underwent rotational chair and caloric tests during March 2012 to March 2013 were included. Slow harmonic acceleration (SHA) test was performed at 0.01, 0.04, 0.16, 0.64, 1.28, and 2.00 Hz. Step velocity tests at the peak velocity of 100o/sec (low-acceleration) and 240o/sec (high-acceleration) were performed. Gains and phases in SHA test and gains and time constants (Tc) in step velocity test were analyzed. Results: In SHA test, decreased gain and phase lead was observed mostly in low frequencies. Gains (phases) at 0.01, 0.04, 0.16, 0.64, 1.28, and 2.00 Hz were 0.2±0.1 (62.2±15.4), 0.3±0.2 (24.5±13.0), 0.4±0.2 (7.2±18.8), 0.5±0.1 (7.2±11.3), 0.7±0.2 (11.0±7.5), and 0.8±0.3 (4.4±14.4), respectively. In step velocity (SV) test, gains stimulating the lesion side were significantly lower than those stimulating the intact side in both low- and high-acceleration SV test (p＜0.05) and per-rotatory gain stimulating the lesion side in high-acceleration SV test was significantly lower than that in low-acceleration SV test. Tc stimulating the lesion side were significantly shorter than those stimulating the intact side in low- acceleration SV test (p＜0.05) but not in high-acceleration SV test. Per- and post-rotatory Tc in high-acceleration SV test stimulating the intact side was significantly lower than those in low-acceleration SV test (p＜0.05). Conclusion: At high-frequency SHA test, gain was pretty normal and phase lead was observed in some patients. High-acceleration SV test showed shortened Tc regardless of the sides, suggesting that high-acceleration SV test can reveal the impaired velocity storage system in patients with vestibular neuritis more frequently than low-acceleration SV test.

Case Report

Spontaneous Recovery of Vestibulo-Ocular Reflex Gain after Bilateral Complete Vestibular Loss Following Head Injury: Ga Young Park, Eun Wook Chung, Jong Sei Kim, Won Ho Chung; Res Vestib Sci. 2012;11(4):146-153.

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Abstract: Dizziness is a frequent complication of head injury and objective evidence of vestibular dysfunction in the dizzy patient following head injury has been reported in literatures. However, there is no report about bilateral spontaneous recovery of caloric response after complete loss of bilateral vestibular function following head injury. A 27-year-old male patient who presented with continuous dizziness and disequilibrium following head injury was diagnosed as diffuse axonal injury after brain magnetic resonance image and bilateral complete loss of vestibular function after caloric and rotary chair test. He showed gradual improvement of dizziness, vestibulo-ocular reflex gain and left caloric response at 2 months after vestibular exercise. After another 4 months, his caloric function was fully recovered, and dizziness disappeared at 16 months after the onset of dizziness. We present this case with reviews of previous literatures about dizziness following head injury and diffuse axonal injury.

Evaluation Studies

Quantitative Analysis of Fixation Index of Caloric Induced Nystagmus and Its Clinical Implication: Joong Yeon Won, Sae Young Kwon, Ji Hee Kim, Hyo Jeong Lee, Hyung Jong Kim, Ja Won Koo, Sung Kwang Hong; Res Vestib Sci. 2012;11(4):123-130.

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Abstract: Background and Objectives: There is no general consensus as to the normal limit or recommended procedure for visual fixation index (VFI) during caloric test because fixation suppression (FS) could be influenced by different variables. In this study, we present our mathematical modeling according to different variables to establish a clinical implication of VFI in patients with vertigo. Materials and Methods: Data were analyzed from a retrospective record of patients who underwent caloric testing. Three subgroups were classified (normal caloric response, unilateral vestibular hypofunction and central vertigo). VFI distribution and mathematical modeling to estimate an associated probability were performed from each group. A receiver operation characteristics (ROC) curve was plotted to determine its diagnostic value. Results: Four hundred eighteen, 67 and 14 patients met our inclusion criteria for normal caloric response, unilateral vestibular hypofunction and cerebellar infarction respectively. VFIs on warm irrigation showed more consistent distribution than cold irrigation in normal caloric response group. In contrast, there was significant inconsistency of VFIs between each side in unilateral vestibular hypofunction group (p>0.05). FS ability was inversely propositional with increase in age on all caloric (p<0.05). The area under the ROC curve of VFIs on warm caloric irrigation was 0.821 and that on cold irrigation was 0.785 for detecting central vertigo. Conclusion: Calibrated normal limit for VFI according to age is needed to ensure its clinical implication. Diagnostic value of VFI and its reliability on warm stimulation was superior to that of cold, which indicates VFI on warm stimulation seems to be a more reliable parameter.

Original Articles

Contralateral Suppression of Transient Evoked Otoacoustic Emission in Vestibular Neuritis: Hoon Young Woo, Jung Hyeob Sohn, Young Sam Yoo, Jeong Hwan Choi; Res Vestib Sci. 2011;10(1):7-11.

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Abstract PDF: Background and Objectives: The etiology of vestibular neuritis is unknown. Many investigators have suggested that this condition spares the inferior vestibular nerve system. However, others have reported that the lesion sometimes affects the inferior vestibular nerve system based on vestibular evoked myogenic potential. The function of the inferior vestibular nerve was studied in acute vestibular neuritis by monitoring medial olivocochlear bundle (MOCB) function. Under normal conditions, contralateral acoustic stimulation has inhibitory effects on ipsilateral otoacoustic emissions through the MOCB. Materials and Methods: Twenty patients that presented with dizziness and spontaneous nystagmus, and were confirmed to have acute vestibular neuritis by rotatory chair and caloric testing were enrolled in this study. We evaluated the evoked otoacoustic emissions with and without contralateral acoustic stimulation in both ears in all patients. The percent loss of normal inhibitory action on otoacoustic emissions was determined in the normal and affected ears. Results: All patients showed inhibitory effects in response to contralateral acoustic stimulation on evoked otoacoustic emissions in normal ears. Fifteen patients (75%) had an absence of contralateral suppression of otoacoustic emissions on the affected side. Conclusion: The findings of this study suggest the presence of dysfunction of the MOCB in patients with acute vestibular neuritis.

Follow-up Changes of Eye Movements by Caloric Stimulation in Patients With Vestibular Neuritis: Mun Su Park, Ga Hyun Park, Yong Soo Jeong, Yeo Jin Lee, Jung Eun Shin, Hong Ju Park; J Korean Bal Soc. 2008;7(1):33-37.

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Abstract PDF: Background and Objectives: A significant recovery of resting activity in the vestibular nuclei ipsilateral to the unilateral labyrinthectomy has been reported by the time symptoms such as spontaneous nystagmus and roll head tilt have largely disappeared. However, the dynamic vestibular response after unilateral vestibular loss to passively imposed vestibular stimuli does not recover. Materials and Methods: We investigated changes of the caloric responses in 32 patients with vestibular neuritis during in- and out-patient visits separated by 2 months in an attempt to identify changes brought about by peripheral and/or central compensation processes. Results: The slow-phase eye velocities stimulated by warm caloric stimulation at acute and follow-up stage were 6.6±6.6°/s, 9.5±9.9°/s in the lesioned side; 28.4±19.1°/s, 24.5±11.6°/s in the intact side. The slow-phase eye velocities stimulated by cold caloric stimulation at acute and follow-up stage were 5.9±7.7°/s, 10.3±8.2°/s in the lesioned side; 19.8±10.3°/s, 18.8±9.9°/s in the intact side. Conclusion: Our findings show that the recovery of caloric responses comes mostly from the recovery of the eye responses to the caloric stimulation in the lesioned side and the eye responses to the caloric stimulation in the intact side does not change over time after vestibular neuritis.

Jongkees’ Formula Reevaluated: Mathematical Significance of CP and Negative SCV Value: Sung Wan Byun; J Korean Bal Soc. 2005;4(2):238-242.

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Abstract PDF: Background
and Objectives: In caloric test, the CP (canal paresis) value was derived from Jongkees formula. The input parameters of the formula were initially nystagmus duration (seconds), which were replaced later with more stable parameters : slow component velocity (SCV, deg/sec). The nystagmus duration cannot be negative value, but SCV can be, especially in acute vestibular loss with excessive spontaneous nystagmus (SN) which is not overcome by caloric nystagmus. This study aims to investigate the occurrence of negative SCV, to check proper processing of negative SCV values in nystagmography software, and to consider the athematical significance of CP and negative SCV values. Materials and Method: Tests with negative SCV values were examined in 690 alternate binaural bithermal caloric tests (open loop system).
Results
Nine percents (62 of 690 tests) showed negative SCV values. The reported CP was erroneously calculated from debased zero SCV values instead of negative SCV values. The underestimated CP (mean 52.1%, SD 21.8%) can be corrected (mean 80.9%, SD 21.8%) by recalculations with negative SCV values.
Conclusion
To produce correct CP values in caloric tests, negative values should be properly processed about the SCV value of caloric nystagmus with opposite direction of physiologic response. The mathematical significance of CP was horizontal coordinate of intersection point of the warm line (LW-RW) and cold line (LC-RC) in butterfly patterncalorigram. Detailed description is presented in figures.

Review

The Correlation between the Change in the Degree of the Canal Paresis in Bithermal Caloric Test and the Degree of Hearing Loss after Chemical Labyrinthectomy in Patients with Meniere's Disease: Chang Woo Kim, San Ho Jung, Won Sang Lee; J Korean Bal Soc. 2004;3(2):404-409.

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Abstract PDF: Background
and Objectives : The chemical labyrinthectomy with aminoglycoside is a good method for vertigo control in Meniere's disease. It is relatively non-invasive and easy procedure, but hearing loss is a awful complication. We aimed to evaluate the relationship between the change in the degree of canal paresis in bithermal caloric test and the degree of hearing change. Materials and Methods : Sixty-five patients of Meniere's disease who underwent chemical labyrinthectomy with streptomycin between October 1997 and December 2001 were included in this study. The minimum follow-up period for the patients was 24 months. Medical records were analyzed retrospectively. Criteria had been prescribed in 1995 by the American Academy of Otolaryngology-Head and Neck Surgery were used. Forty patients were tested a caloric response before and after the chemical labyrinthectomy. We analyzed the vertigo control rate, the change of the canal paresis and the change of hearing level.
Results
: Vertigo was controlled in 90.8% of the 65 patients. Twelve patients of total 65 patients were decreased hearing level more than 10 ㏈ after this procedure. Even though the severity of canal paresis increased, the hearing ability of most patients was unaffected. Some patients who had only slight canal paresis happened to suffer from hearing loss.
Conclusion
: There was no correlation between the change in the degree of canal paresis in the bithermal caloric test and the degree of the hearing change.

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