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Effects of Changes of Plateau and Rise/Fall Times on Ocular Vestibular Evoked Myogenic Potentials
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Yeo Jin Lee, Soo Hee Han, Eun Jung Ha, Yong Soo Jung, Hi Boong Kwak, Mun Su Park, Jung Eun Shin, Hong Ju Park
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J Korean Bal Soc. 2008;7(2):193-196.
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 Abstract
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- Background and Objectives: The ocular vestibular evoked myogenic potential (OVEMP) is a recently discovered test of labyrinthine function, analogous to the cervical VEMP. Recent works have demonstrated the existence of OVEMPs, which likely reflect otolith-ocular reflex. The purpose of this study was to identify the optimal plateau and rise/fall times of short tone bursts to detect OVEMPs in healthy subjects.
Materials and Methods: Thirteen healthy subjects (26 ears) were included in this study. Surface electromyographic activity was recorded from active electrodes placed inferior to each eye. Stimulation with 500 Hz short tone bursts was used. We used a variety of plateau and rise/fall times. Three different plateau times (1, 2, and 3 ms) and rise/fall times (0.5, 1, and 2 ms) were used. The incidence, amplitudes and latencies were compared.
Results: VEMP responses were clearly observed in all 26 ears at the plateau time of 2 ms and two rise/fall times (0.5 and 1 ms). The amplitudes in the individual ears tested were lower at the rise/fall time of 2 ms than at the other conditions. The amplitudes were lower at the plateau time of 3 ms compared to the other conditions. When the rise/fall time was prolonged from 0.5 to 2 ms, the n1 and p1 latencies were prolonged in parallel. However, there was no such change in latencies according to the plateau times.
Conclusions: Our findings show that the ideal stimulation pattern for evoking OVEMP is at the rise/fall times of 0.5 or 1 ms and the plateau time of 2 ms. The waveform morphology of the VEMP responses observed with this stimulation pattern was simultaneously the most constant and marked.
Key words: Evoked potentials, Ocular VEMP, Vestibulo-ocular reflex, Otolith
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Vibration-Induced Nystagmus in Patients with Vestibular Disorders
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Yeo Jin Lee, Hong Ju Park, Jung Eun Shin, Jae Yoon Ahn, Ga Hyun Park, Yong Soo Jung, Hi Boong Kwak, Jin Seok Yoo
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J Korean Bal Soc. 2007;6(2):192-195.
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Abstract
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- Background and Objectives: It has been reported that vibration applied either on the mastoid or the sternocleidomastoid (SCM) muscles induces nystagmus in patients after unilateral vestibular neuritis. The aims of the study were to characterize the vibration-induced nystagmus (VIN) in patients with various vestibular disorders and to compare the results of VIN to unilateral weakness in caloric test.
Materials and Methods: Fifthy-four patients with Meniere’s disease, 58 patients with unilateral vestibular neuritis, 170 patients with migraine-associated dizziness, and 78 patients with chronic recurrent vestibulopathy were included. We recorded eye movements during unilateral 100-Hz vibration on the mastoids and SCM muscles. The bithermal caloric test was also performed. Abnormal criteria of VIN were slow-phase slow-phase velocity (SPV) at 4 all different conditions ≥ 2°/s with the same directions or mean of SPV at vibration on both mastoids or both SCM muscles ≥ 5°/s with the same directions.
Results: In Meniere’s disease, 28 of 57 (49.1%) of patients show pathologic VIN, 21 of 57 (36.8%) show pathologic canal paresis. 14 of 57 (24.6%) show abnormalities in both tests, and 35 of 57 (61.4%) show any abnormalities in either test. In unilateral vestibular neuritis, 43 of 58 (77.6%) showed pathologic VIN, 58 of 58 (100%) show canal paresis. In migraine-associated dizziness, 48 of 170 (28.2%) showed pathologic VIN, 58 of 170 (18.8%) show canal paresis. 15 of 170 (8.8%) showed abnormalities in both tests, and 65 of 170 (38.2%) show any abnormalities in either test. In chronic recurrent vestibulopathy, 23 of 78 (29.5%) of patients show pathologic VIN and 17 of 78 (21.8%) show pathologic canal paresis. Seven of 78 (9.0%) showed abnormalities in both tests, and 33 of 78 (42.3%) show any abnormalities in either test.
Conclusion: VIN test can increase the sensitivity in detecting vestibular imbalance in vestibular disorders when combined with caloric test.
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Changes of Vibration-Induced Nystagmus by Age in Normal Subjects
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Yong Soo Jung, Hong Ju Park, Jung Eun Shin, Jae Yoon Ahn, Ga Hyun Park, Hi Boong Kwak, Yeo Jin Lee, Jin Seok Yoo
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J Korean Bal Soc. 2007;6(2):186-191.
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Abstract
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- Background and Objectives: It has been reported that vibration applied either on the mastoid or on the sternocleidomastoid (SCM) muscles induces nystagmus in normal subjects. The aims of the study were to characterize the direction and velocity of slow-phase eye movement which is induced by vibration in normal subjects and to propose the mechanism of vibration-induced nystagmus (VIN) in normal subjects.
Materials and Method: We recorded eye movements during unilateral 100-Hz vibration on the mastoid bone and SCM muscles in 56 normal subjects. The subjects were divided into 4 groups in ages (20s, 30s, 40s, 50~60s). The directions of VIN, the degree of maximal slow-phase eye velocities were analyzed according to age. Positive value means slow-phase velocity (SPV) to the right side.
Results: In 20s, vibration on right/left mastoids induced SPV of 1.2±2.0°/sec, 0±2.1°/sec and on right/left SCM muscles, 1.1±1.9°/sec, -1.2±2.5°/sec. In 30s, vibration on right/left mastoids induced SPV of 3.3±3.8°/sec, -0.3± 1.4°/sec and on right/left SCM muscles, 2.8±4.2°/sec, -1.0±1.5°/sec. In 40s, vibration on right/left mastoids induced SPV of 0±1.7°/sec, -0.2±1.2°/sec and on right/left SCM muscles, 0±1.8°/sec, 0±1.0°/sec. In 50~60s, vibration on the right/left mastoids induced SPV of -1.3±1.3°/sec, 1.2±1.3°/sec and on right/left SCM muscles, -0.6±0.9°/sec, 0.9 ±1.5°/sec. The directional preponderance of the slow-phase eye movement to the vibrated side was statistically significant in 20s and 30s, however, the preponderance of the slow-phase eye movement changed into the non-vibrated side in 50~60s.
Conclusion: The proprioceptive input, changing major rotator from the inferior oblique muscle to the sternocleidomastoid muscles might explain the change of the directional preponderance of the slow-phase eye movements in normal subjects according to ages. Although this directional preponderance is not consistent in all age groups, it is still important in discriminating normal responses from abnormal responses which can be induced by vibration.
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Follow-up Examination of Vibration-Induced Nystagmus in Patients with Unilateral Vestibular Neuritis
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Hong Ju Park, Jung Eun Shin, Jae Yoon Ahn, Ga Hyun Park, Yong Soo Jung, Hi Boong Kwak, Yeo Jin Lee, Jin Seok Yoo
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J Korean Bal Soc. 2007;6(2):172-175.
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Abstract
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- Background and Objectives: The aim of this study was to verify if vibration-induced nystagmus in patients with vestibular neuritis changed over time and to compare the results of vibration-induced nystagmus (VIN) test to those of caloric test.
Materials and Method: We compared VIN results with those of caloric testing in 23 patients (M:F = 11:12, 15~67 years old) with unilateral vestibular neuritis seen at onset and in follow-up for around 2 months. The eye movement recordings were made and the maximum slow-phase eye velocities (SPV) were calculated during vibration. If spontaneous nystagmus was present, it was subtracted from the slow-phase eye velocities of VIN.
Results: In acute stage, VIN of which SPV was directed towards the lesioned side was observed in 21 (91%). In follow-up, VIN of which SPV was directed towards the lesioned side was observed in 19 (83%). There was a significant decrease of the SPV of VIN over time. Significant correlations were observed in between canal paresis & SPV of VIN in both acute and follow-up stages.
Conclusion: Our findings show that VIN test can predict the severity of vestibular asymmetry not only in acute stage but also in follow-up stage. Our results suggest that vibration-induced nystagmus might represent the peripheral vestibular asymmetry in patients with vestibular neuritis.
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Comparison of Air Caloric Test and Vibration-Induced Nystagmus Test in Patients with Unilateral Chronic Otitis Media without Vertigo
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Jae Yoon Ahn, Hong Ju Park, Jung Eun Shin, Ga Hyun Park, Yong Soo Jung, Hi Boong Kwak, Yeo Jin Lee, Jin Seok Yoo
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J Korean Bal Soc. 2007;6(2):167-171.
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Abstract
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- Background and Objectives: The aims of the study were to characterize the vibration-induced nystagmus (VIN) and air caloric test in patients with unilateral chronic otitis media, and to clarify the clinical availability of VIN by comparing the results of VIN test with those of air caloric test.
Materials and Methods: Nineteen patients with unilateral chronic otitis media who had had no vestibular symptoms in past history were investigated. Pure tone audiometry (PTA), air caloric, VIN and subjective visual vertical (SVV) tests were done and the results were analyzed to estimate the utility for investigating vestibular imbalance.
Results: If we consider a patient with abnormal results from two or more tests as a patient with latent vestibular imbalance, because they had no previous vestibular symptoms, 3 patients was considered to have latent asymmetric vestibular function. False positive rate were 32% in air caloric test, 5% in VIN test and 0% in SVV test.
Conclusion: Our findings show that vestibular imbalance in patients with chronic otitis media should be determined through various tests and vibration-induced nystagmus test can be more useful than air caloric test in estimating the vestibular imbalance.
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Otolith Function Tests in Patient with Meniere’s Disease
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Hong Ju Park, Jung Eun Shin, Jae Yoon Ahn, Ga Hyun Park, Yong Soo Jung, Hi Boong Kwak, Yeo Jin Lee, Jin Seok Yoo
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J Korean Bal Soc. 2007;6(2):127-131.
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- Background and Objectives: The aims of this study were to measure otolith function using subjective visual vertical (SVV) test and vestibular evoked myogenic potential (VEMP) test in patients with unilateral Meniere’s disease, and to see the relationship of the otolithic impairment with caloric and audiologic results.
Materials and Methods: Twenty two patients with unilateral Meniere’s disease who received treatment and also had been tested for pure tone, caloric, SVV and VEMP tests were enrolled. All the tests were done simultaneously.
Results: Five of 22 (23%) patients showed abnormal tilt to the lesion side in SVV test, and 13 of 22 (59%) patients showed abnormal VEMP results on the affected side. There was no correlation between SVV tilts and unilateral weakness (UW) in caloric tests or pure-tone average. There was also no difference of UW in patients with or without VEMP abnormalities. Two patients showed abnormal finding in both SVV & VEMP tests. One patient showed UW (47%) and SVV tilt (3.08°) to the lesion side, and the other showed normal UW and SVV tilt (3.22°) to the lesion side.
Conclusion: Our results demonstrate that the otolith system was implicated in 16 out of 22 (73%) patients with Meniere’s disease. However, there was no correlation between the abnormal results of the three tests and these findings suggest that impairment of the otolithic function is depending on the extent and/or the localization of Meniere’s disease, suggesting vestibular rehabilitation for the specific lesion might be helpful.
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Otolith Function Tests in Patient with Vestibular Neuritis
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Hong Ju Park, Jung Eun Shin, Dae Bo Shim, Hyang Ae Shin, Sang Kyun Lim, Jae Yoon Ahn, Yong Soo Jung, Jin Suk Yu
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J Korean Bal Soc. 2006;5(1):49-54.
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- Background
and Objectives: Vestibular evoked myogenic potentials (VEMP) test provides a useful method for assessment of saccule function and the functional integrity of the inferior vestibular nerve, and subjective visual vertical (SVV) abnormalities are presumably related to a lesion of the utricle. The aim(s) of this study were to measure otolith function using SVV and VEMP tests, and to define the influence of the otolithic organs in patients suffering from vestibular neuritis.
Materials and Method: From September 2005 to January 2006, twelve patients who received treatment in hospital and also had been tested for caloric test, subjective visual vertical (SVV) and vestibular evoked myogenic potential (VEMP) tests with unilateral vestibular neuritis were enrolled. All the tests were done within 8 days after the onset of their symptoms, simultaneously. The SVV was measured in 34 normal subjects as well as in patients.
Results
Eight of 12 patients showed abnormal tilt to the lesion side in SVV test, and five of 8 patients showed no VEMP on the affected side. There was no correlation between SVV tilts and unilateral weakness (UW) in caloric tests. Two patients with abnormal UW (54, 82%) showed normal finding in SVV & VEMP tests. One patient with abnormal UW (83%) and SVV tilts (18.04˚) to the lesion side was normal in VEMP test. Two patients with abnormal UW (28, 37%) and no response in VEMP test were normal in SVV test.
Conclusion
Our results demonstrate that the incidence of abnormal results were 62.5, 66.7% in VEMP and SVV tests in acute stage of vestibular neuritis, respectively. There was no correlation between the abnormal results of the tests and these findings suggest that impairment of the otolithic function is depending on the extent and/or the localization of vestibular neuritis.
Key Words : Vestibular neuritis, Otolith, Vestibular function tests, Subjective visual vertical, Vestibular evoked myogenic potentials
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