Research in Vestibular Science

Review

The Principle and Methodology of Vestibular Evoked Myogenic Potential: Min Young Lee, Myung Whan Suh; Res Vestib Sci. 2015;14(1):9-14.

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Abstract PDF: Vestibular evoked myogenic potential (VEMP) has developed as a broadly applied vestibular function test in clinics from its introduction in 1992. In the past, there was only one well known VEMP protocol, which is cervical VEMP, however recently ocular VEMP is also popular. Therefore, clarifying the VEMP recording protocol (cervical VEMP or ocular VEMP) before discussing the VEMP
result
has become essential. There is considerable difference regarding this VEMP test from other vestibular function tests. VEMP is thought to be assessing the functions of the otolith organs (utricle and saccule) which are evoked by acoustic stimulus. Cervical VEMP is valuable since this is the only available test method which could speculate the function of the saccule and inferior vestibular nerve. Still, there’s less clearly understood part regarding the central pathway of VEMP. However, many clinicians and researchers participating in vestibular research speculate that this functional test will have a more dominant role in the near future. Here we describe the basic principles and methodological considerations regarding VEMP recording.

Original Article

Diagnostic Value of Cochlear Hydrops Analysis Masking Procedure in Meniere's Disease in Comparison with Electrocochleography: Ju Sang Lee, Eun Sun Park, Sung Kwang Hong, Jung Hak Lee, Hyo Jeong Lee, Hyung Jong Kim; Res Vestib Sci. 2011;10(1):19-25.

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Abstract PDF: Background and Objectives: Patients with Meniere’s disease often present with a great variety of symptoms, especially at the onset of the disease. However, there is no single test that is definitive for making the diagnosis of Meniere’s disease. Recently, a new diagnostic test, the cochlear hydrops analysis masking procedure (CHAMP) was introduced as a test for endolymphatic hydrops. The aim of this study is to evaluate the diagnostic value of CHAMP test in Meniere’s disease in comparison with that of electrocochleography. Materials and Methods: The CHAMP test and electrocochleography were simultaneously performed in 14 cases of definite Meniere’s disease and 8 normal healthy volunteers (16 ears). Positive criteria were defined as being more than 0.35 in summating potential/action potential (SP/AP) ratio, 0.3 ms or less in latency delay and 0.95 or less in complex amplitude ratio. Measured parameters from each test were compared between the groups, and sensitivity and specificity of each test in diagnosing Meniere’s disease were calculated. Results: There was no significant difference in the SP/AP ratio of electrocochleography between the Meniere’s disease and control groups. In CHAMPtest, the latency delay was shorter and the complex amplitude ratio was smaller (p<0.001). While taking positive results from both test parameters, the sensitivity and specificity of CHAMP test were 85.7% and 87.5%, respectively. Conclusion: The CHAMP seems to be a clinically useful tool in diagnosing Meniere’s disease and might be better than electrocochleography to detect endolymphatic hydrops.

Case Report

Auditory Neuropathy Accompanying Unilateral Vestibulopathy: Hye Young Kim, Jae Yun Jung, Chung Ku Rhee, Myung Whan Suh; Res Vestib Sci. 2009;8(1):60-65.

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Abstract PDF: Auditory neuropathy is a term used to describe abnormal auditory brain stem response (ABR) in the presence of preserved cochlear outer hair cell functions which can be measured by otoacoustic emissions (OAE). We report a case of auditory neuropathy accompanying unilateral vestibular hypofunction and benign paroxysmal positional vertigo. The patient was a 50-year-old man who had experienced hearing loss and tinnitus which started two weeks ago. He had taken several medicines for the last few months due to his lung cancer and tuberculosis. ABR and OAE were checked and the results were compatible with auditory neuropathy. To evaluate his vestibular function, video nystagmography, rotatory chair and oculomotor test were checked. The results were compatible with left unilateral vestibular loss and left lateral canal cupulolithiasis. But the patient experienced nearly no vertigo during his daily life. As presented in this case, most of the auditory neuropathy patients do not complain of vertigo. This is probably due to long term central compensation or maybe due to the decreased nerve conduction of the vertiginous sensation. Vestibular evaluation may be crucial in order to detect masked vestibular dysfunction and to protect these patients from imbalance accidents. Key Words: Auditory neuropathy; Vestibular Neuronitis; Evoked Potentials, Auditory, Brain Stem; Otoacoustic Emissions

Original Articles

Effects of Changes of Plateau and Rise/Fall Times on Ocular Vestibular Evoked Myogenic Potentials: Yeo Jin Lee, Soo Hee Han, Eun Jung Ha, Yong Soo Jung, Hi Boong Kwak, Mun Su Park, Jung Eun Shin, Hong Ju Park; J Korean Bal Soc. 2008;7(2):193-196.

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Abstract PDF: 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

Diagnostic Value of Vestibular Evoked Myogenic Potential in Acoustic Neuroma: Young Jin Ahn, Sung Kwang Hong, Ji Soo Kim, Ja Won Koo; J Korean Bal Soc. 2007;6(2):138-142.

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Abstract PDF: Background and Objectives: Considering vestibular evoked myogenic potential (VEMP) represents functional integration of the inferior vestibular nerve and large proportion of acoustic neuroma (AN) originate from inferior vestibular nerve, VEMP test may provide more valuable information than ABR and the caloric test in terms of evaluating functional integration as well as screening test. Authors hope to clarify such hypothesis and also analyzed if parameters differ between cochlear lesion and retrocochlear lesion. Materials and Methods: Authors analyzed the results of VEMP test in 27 patients (10 males and 17 females) of AN and in 24 patients (9 males and 15 females) of unilateral definite Meniere’s disease (MD). Right-left difference of interpeak latency (IPL) and interaural amplitude difference (IAD) were used as parameters of VEMP. Longest diameter of the enhanced area was measured as the size of tumor on the axial view of Gadolium enhanced T1 weighted magnetic resonance image. Results: VEMP was abolished in 15 out of 27 AN patients (54.5%). Among the remaining 12 patients, 1 patient showed increased IPL and IAD at same time, while 2 patients exhibited increased IAD. The mean diameter of tumor in the group who showed positive VEMP waves was significantly smaller (0.95 cm) than that of abolished VEMP group (2.22 cm)(p=0.004). Similar tendency was also present in ABR and Caloric test. However, there was not significant difference between MD and AN in the latencies and amplitudes. Conclusions: VEMP test may not provide diagnostic information in smaller AN, especially less than 1 cm. And parameters of VEMP were not differ between cochlear and retrocochlear lesion. However, VEMP response seems still important for the comprehensive understanding of peripheral cochleovestibular status in addition to ABR and caloric test.

Role of Vestibular Evoked Myogenic Potentials to Elevate the Sensitivity of Objective Tests in Early Meniere’s Disease: Ik Joon Choi, Sung Kwang Hong, Ji Soo Kim, Ja Won Koo; J Korean Bal Soc. 2007;6(1):16-20.

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Abstract PDF: Background and Objectives: Diagnosis of Meniere’s disease (MD) is based on detailed medical history and audiometry in addition to electrocochleography (ECoG). However, the sensitivity of ECoG is rather low and the diagnosis seems to be rather obscure if the patient is evaluated after resolution of acute symptom, especially in early stage of disease without substantial hearing loss. In such cases, if a patient complains recurrent episodes within short term period, any objective result would be beneficial to initiate medical treatment such as diuretics. Since the saccule is the main target organ in MD, authors suppose vestibular evoked myogenic potential (VEMP) test combined with ECoG may elevate the diagnostic sensitivity in MD. Aim of study is to evaluate the possibility of this suggestion. Materials and Method: Thirty-four patients of unilateral MD who have hearing loss less than 40 dB and onset of first attack within 1 year were included in this study. They underwent VEMP, caloric test and ECoG. Abnormal rates of each test and results of combination were analyzed according to the group of MD. Results: Patients with abnormal results in VEMP, ECoG and calorict tests were 29%, 15% and 35%, respectively. Patients showed abnormal results either in VEMP or ECoG were 41% in all MD and 72% in definite group. Conclusions: To get higher objective evidence of cochleovestibu

Analysis of Parameters of Vestibular-Evoked Myogenic Potentials in Sudden Sensorineural Hearing Loss without Vertigo: Min Hyun Park, Woo Jin Jeong, Jae Jun Song, Ji Soo Kim, Ja Won Koo; J Korean Bal Soc. 2005;4(2):206-211.

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Abstract PDF: Background
and Objective: Vestibular evoked myogenic potentials (VEMP) has been promoted as a means of assessing the integrity of saccular function. Even though sacculospinal reflex may not be influenced by abnormality of cochlear pathway, saccule is closely related with cochlea in its embryological development and also in geographic location. So authors hypothesized the presence of functional alterations of saccule in patients with sudden sensorineural hearing loss who do not complain of vertigo, since saccular dysfunction may not induce subjective vestibular symptoms or signs. Authors tested saccular function in those patients using VEMP and analyzed the parameters according to other clinical indicators. Materials and Method: From July to September 2005, 22 patients who diagnosed with unilateral sudden sensorineural hearing loss without vertigo were enrolled. The patients who had vertigo as initial symptom or showed spontaneous nystagmus were excluded. All patients received conventional audiometry, tone-burst VEMP test, and caloric test. We analyzed P13 and N23 latency, interpeak amplitude and asymmetric ratio of amplitude. The patients divided to complete hearing recovery, partial recovery, and no response group according to treatment outcome. The correlation between parameters and treatment result was analyzed.
Results
In 2 out of 22 patients (9.1%), VEMP waves were not detected. There was no latency delay in affected ear. But the interpeak amplitude of the affected ear was significantly smaller than that of healthy side (paired t test, p=0.02). Patients who did not respond to treatment showed smaller interpeak amplitude than those who showed complete recovery.
Conclusion
Most patients of idiopathic sudden sensorineural hearing loss without vertigo seem to show normal VEMP waves. But some parameters regarding amplitude had abnormal findings in affected ear. Further studies with larger sample size seem to be necessary to elucidate such outcomes.

Clinical Trial

Vestibular Evoked Myogenic Potential Generated by 500 Hz Tone Burst in Unilateral Peripheral Vestibulopathy: Ja Won Koo, Dong Hwan Roh, Chang Hee Kim, Jin Young Kim, Ji Yeon Yu, Kwang Dong Choi, Ji Soo Kim; J Korean Bal Soc. 2004;3(2):356-361.

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Abstract PDF: Background
and Objectives : Vestibular evoked myogenic potential (VEMP) has become a valuable diagnostic tool evaluating the integrity of sacculocollic reflex and has been done using click sound in most previous clinical trials. This study aims to investigate VEMP responses generated by 500 Hz tone burst in unilateral peripheral vestibulopathy and compare the response with caloric test and subjective visual vertical (SVV). Materials and Method : Clinical records of 37 patients (18 men and 19 women, aged 14-80 years) with unilateral peripheral vestibulopathy were reviewed. Diagnoses were Meniere's disease (n=13), vestibular schwannoma (n=4) and acute peripheral unilateral vestibulopathy (n=20). They underwent 500Hz tone burst VEMP, caloric test and SVV test. Thirteen healthy volunteers (26 ears, 8 men and 5 women, 25~41 years) with normal hearing were enrolled as control group.
Results
: VEMP response was present in every control ear using 500 Hz tone burst stimuli. In Meniere's disease, VEMPs were positive in 57% (4/7) of patients with abnormal caloric response group and 83% (5/6) with normal caloric response. In acute peripheral vestibulopathy, VEMPs were positive in 47% (9/19) of patients with abnormal caloric response, 0% (0/1) with normal caloric response. The average of CP (canal paresis) in positive VEMP group was 62.4% and that in negative VEMP group was 48.2% (P>0.05).
Conclusion
: Reliable and reproducible test results can be obtained using 500 Hz tone burst stimuli. VEMP results were not in concordance with other vestibular tests, which reflects the dynamic process of dizziness and variable extent of pathology in each case.

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