Cervical Vestibular Evoked Myogenic Potential (cVEMP) is a routine vestibular test which checks the integrity of vestibulocollic reflex (VCR) pathway. Clinically, 500-Hz tone burst is widely used stimulus to evoke a cVEMP. Although several studies have suggested different plateau times (PT) for eliciting cVEMPs, but not many have reported the optimal PT for evoking cVEMP using 500 Hz tone burst stimuli. Therefore, the present study aimed to investigate the effect of PT on cVEMPs elicited by 500 Hz tone burst at 95 dBnHL using four different PT (0, 2, 4 and 10 ms). Thirty healthy adults with normal hearing and vestibular systems participated in this study. Results revealed that the P1 latency was significantly longer for PT 10 ms compared to other PTs. N1 latency was significantly prolonged for long PT of 10 ms compared to PT 2 ms. P2 latency showed no significant differences among PTs. The P1-N1 inter-amplitude values however revealed no significant difference across all PTs. It was found that the P1-N1 inter-amplitude was severely affected after 4 ms of PT. This study concluded that the PT of either 0 or 2 ms yielded the most robust cVEMP.
Vestibular Evoked Myogenic Potentials

Myogenic potentials evoked by air conducted sound (ACS), bone conducted vibration (BCV) or galvanic pulses can be recorded with surface electrodes over contracted muscles. These myogenic potentials are of vestibular origin (utricle and saccule) and so these potentials are called vestibular evoked myogenic potentials (VEMPs). Since the vestibular system has projections to many muscle systems, there are many such VEMPs. In this review, we discuss the generated origin, response pathway, waveform characteristics and clinical application of ocular vestibular-evoked myogenic potential (oVEMP).
Humans ; Vestibular Evoked Myogenic Potentials

Recent studies suggest that changes of cervical vestibular-evoked myogenic potential (cVEMP) could be observed postoperatively, which reflects the degree of damage to saccule caused by cochlear implant (CI). The waveform of cVEMP can display the influences of surgical methods, ear disease condition, machine status and other factors on saccule, therefore it shows important clinical value in diagnosis and treatment. Two possible changes of cVEMP may be observed after CI. One is negative response and the other is impairment, which reflects surgical injury to saccule with varing degree. However, a uniform quantitative conclusion in cVEMP parameters is still expected. By reviewing the studies in cVEMP of CI reciepients, a typical changing pattern was discovered and a more comprehensive understanding about vestibular changes after cochlear implant was achieved.
Cochlear Implantation ; Humans ; Vestibular Evoked Myogenic Potentials

No abstract available.
Meniere Disease ; Vestibular Evoked Myogenic Potentials

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.
Acoustics ; Evoked Potentials ; Otolithic Membrane ; Saccule and Utricle ; Vestibular Evoked Myogenic Potentials ; Vestibular Function Tests ; Vestibular Nerve

OBJECTIVES: To investigate the vestibular evoked myogenic potentials (VEMP) results in benign paroxysmal positional vertigo (BPPV) patients and to verify its clinical applications in BPPV. SUBJECTS AND METHODS: Forty-one patients with diagnosis of BPPV and 92 healthy volunteers who underwent VEMP testing. Patients were treated by canalith repositioning maneuvers according to the affected canal, and testing of VEMP was performed at diagnosis and after treatment. RESULTS: VEMP results of BPPV patients showed prolonged p13 and n23 latencies compared with those of the control group, and we could not find any significant difference in VEMP latencies between patients with posterior and horizontal canal type of BPPV. The number of times that the maneuver was repeated did not correlate with the degree of latency prolongation, but in the "no response" group, the number of times was considerably greater than those in the "response" group. CONCLUSIONS: We found that VEMP latencies are increased in BPPV patients, which may signify neuronal degenerative changes in the macula of the saccule. When an extensive neuronal damage was suspected by VEMP results such as "no response" in VEMP, the disease progress showed a chronic and resistive course. Therefore, we propose that VEMP could be a useful method to determine a clinical prognosis of patients with BPPV.
Humans ; Neurons ; Prognosis ; Saccule and Utricle ; Vertigo ; Vestibular Evoked Myogenic Potentials

BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potentials (VEMP) have become a good diagnostic tool to evaluate the integrity of the vestibulocollic reflex. To investigate the standard recording of VEMP response in normal hearing subjects, the authors studied the effects of test positions and different acoustic stimulations on the VEMP. SUBJECTS AND METHOD: We performed VEMP on both ears of thirty normal hearing volunteers. Three acoustic stimulations (clicks and 500 Hz and 1,000 Hz short tone bursts) and four test positions were presented alternately to evoke VEMP. The latencies of peak p13 and n23, p13n23 interpeak latency (IPL) and amplitude were measured by EMG equipment and compared by statistical program. We also made up questions for the compliance of the test positions. RESULTS: The effects of test positions p13 latency had no significant difference on all test positions except between test position 2 and 4, n23 latency and p13n23 IPL had shortest waveform on test position 2, p13n23 amplitude had the largest waveform in test position 4. Acoustic stimulations on all test positions were influenced that clicks had shorter waveform about 2-3 ms than STBs on p13 latency and n23 latency, STBs had larger waveform than clicks on p13n23 amplitude. And the compliance of the test positions exhibited highest comfort in test position 1. CONCLUSION: Test position 1 had higher VEMP response rates and compliance, 500 Hz STB had a largest p13n23 amplitude. Therefore we recommend that the ideal conditions were position 1 and 500 Hz STB for acoustic stimulations to evoke VEMP.
Acoustics* ; Compliance ; Ear ; Hearing ; Reflex ; Vestibular Evoked Myogenic Potentials* ; Volunteers

Humans ; Vertigo ; diagnosis ; physiopathology ; Vestibular Evoked Myogenic Potentials

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.
Ear ; Electrodes ; Evoked Potentials ; Eye ; Incidence ; Otolithic Membrane ; Reflex ; Reflex, Vestibulo-Ocular ; Vestibular Evoked Myogenic Potentials

BACKGROUND AND OBJECTIVES: Recent works have demonstrated the existence of ocular vestibular evoked myogenic potentials (OVEMPs), which reflects otolith-ocular reflex. The purpose of this study was to identify an appropriate gaze position to detect OVEMPs produced by air-conducted sound stimulation in healthy subjects. SUBJECTS AND METHOD: Twenty four healthy subjects (35 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 to activate the vestibular end-organs. RESULTS: Sound stimulation evoked negative-positive biphasic responses on both ipsilateral and contralateral eyes, while responses were contralateral eye-dominant. Contralateral eye responses had higher response incidence and larger amplitudes. Altering the direction of gaze generally changed the incidence and size of the inter-peak amplitudes. The higher incidence and larger amplitudes were recorded when the eyes are directed to the superior and ipsilateral side to the sound stimulation. In that gaze position, the amplitude was 5.3 micronV, the first negative peak latency was 10.5 ms and the following positive peak latency was 15.4 ms on the average. CONCLUSION: OVEMPs can be evoked using an air-conducted 500 Hz tone burst and are best recorded contralaterally with a upward gaze towards the source of sound stimulation. Further changes of the test parameters are needed for higher and consistent responses.
Electrodes ; Evoked Potentials ; Eye ; Incidence ; Reflex ; Reflex, Vestibulo-Ocular ; Saccule and Utricle ; Vestibular Evoked Myogenic Potentials