Yi-Ho Young

Augmentation of Vestibular Evoked Myogenic Potentials: An Indication for Distended Saccular Hydrops †

Objective/Hypothesis Vestibular evoked myogenic potential (VEMP) testing has become a well‐established test to explore the sacculo‐collic pathways in human. The aim of the present study is to establish a clinical indication for saccular hydrops by VEMP testing.

Vestibular Evoked Myogenic Potentials in Brainstem Stroke

Objectives/Hypothesis Despite its widespread application in the posterior fossa tumor, the study of vestibular evoked myogenic potential (VEMP) in cases of posterior fossa stroke remains scarce. The purpose of the study was to establish the role of VEMP in patients with brainstem stroke.

Vestibular Evoked Myogenic Potentials in Basilar Artery Migraine

Objectives/Hypothesis: Because the sacculocollic reflex is a descending pathway passing through the territory of basilar artery, the aim of the study was to investigate whether hypoperfusion affects this pathway by applying vestibular evoked myogenic potential (VEMP) testing in patients with basilar artery migraine.

Vestibular evoked myogenic potentials in delayed endolymphatic hydrops.

Objective/Hypothesis Vestibular evoked myogenic potential (VEMP) has become an established test to explore the sacculo‐collic reflex. The study aims to investigate the VEMPs in cases of delayed endolymphatic hydrops because greatly dilated saccule was observed in histopathological specimens of delayed endolymphatic hydrops.

Vertigo from herpes zoster oticus: superior or inferior vestibular nerve origin?

Objective/Hypothesis This study aims to analyze which division of vestibular nerve in the internal auditory canal is responsible for inducing vertigo in patients with herpes zoster oticus (HZO).

Vestibular evoked myogenic potentials are intact after sudden deafness

Objective To evaluate vestibular evoked myogenic potentials (VEMPs) in cases of sudden deafness, and to confirm the noncochlear origin of the VEMPs. Study Design Prospective study. VEMPs, which were evoked by short tone burst (95 dB nHL) stimulation, were recorded in 20 patients with unilateral, idiopathic sudden deafness. The results of the deaf ears were compared with those of the contralateral healthy ears and the normal control ears. The relations between VEMPs and the hearing level or caloric response were then investigated. Results All 20 of the deaf ears displayed normal biphasic VEMPs. The mean latencies of p13 and n23, as well as mean amplitude p13-n23, were 15.1 ± 2.8 msec, 20.7 ± 3.3 msec and 25.2 ± 12.6 &mgr;V, respectively, not significantly different to either the contralateral healthy ears (p > 0.05) or the normal control ears (p > 0.05). Five deaf ears displayed canal paresis or absent caloric response, whereas the remaining 15 ears revealed normal caloric response. Conclusion All the lesioned ears of patients with idiopathic sudden deafness exhibit normal biphasic VEMPs. Neither the hearing level nor the caloric response correlated to the VEMPs.

Potential application of ocular and cervical vestibular‐evoked myogenic potentials in meniere's disease: A review

By stimulating the ear with air‐conducted sound or bone‐conducted vibration stimuli, vestibular‐evoked myogenic potential (VEMP) can be recorded on the contracted neck muscles, termed cervical VEMP (cVEMP), and on the extraocular muscles, termed ocular VEMP (oVEMP). These two electrophysiological tests expand the test battery for clinicians to explore the dynamic otolithic function, adding a potential usefulness to the sacculocollic reflex and vestibulo‐ocular reflex, respectively. The inner ear test battery, including audiometry, and cVEMP, oVEMP and caloric tests, is designed for complete evaluation of the inner ear function, namely, the cochlea, saccule, utricle, and semicircular canals, respectively. Using this test battery to study the localization and prevalence of hydrops formation reveals that the declining function in the cochlea, saccule, utricle, and semicircular canals mimics the declining sequence of hydrops formation in temporal bone studies. This study reviewed the physiological results in Menieres patients via the inner ear test battery, especially the potential application of the oVEMP and cVEMP tests, to correlate with the histopathological findings of Menieres disease. Laryngoscope, 2012

Aging effect on the ocular vestibular-evoked myogenic potentials.

Objective: This study applied ocular vestibular-evoked myogenic potential (oVEMP) tests in healthy subjects of various ages to measure the effect of aging on oVEMPs quantitatively. Study Design: Prospective study. Setting: University hospital. Subjects: Seventy healthy subjects with the ages ranging from 24 to 76 years were divided into 6 groups by decade. Each group consisted of 10 subjects in 1 decade except 20 subjects in the group of 60 to 69 years. Main Outcome Measures: All subjects underwent oVEMP tests using bone-conducted vibration stimuli. Results: All subjects in groups of 20-59 years showed 100% response rates of clear oVEMPs, while 22 (55%) of 40 eyes in group of 60-69 years and 8 (40%) of 20 eyes in group of ≥ 70 years had clear oVEMPs, exhibiting significant differences between those below and over 60 years of age. The mean nI and pI latencies also showed significantly prolonged in those over 60 years, whereas the mean nI-pI amplitude reduced significantly in subjects over 40 years. However, the asymmetry ratios of oVEMPs did not differ significantly among the age groups. Analyses between the age factor and characteristic parameters revealed that significant correlations existed between the age factor and the nI latency, pI latency and nI-pI amplitude, but not the nI-pI interval. Conclusion: Aging effect (> 60 years old) on the oVEMPs includes reduced response rate, prolonged nI and pI latencies, and decreased nI-pI amplitude. Thus, age factor should be taken into consideration when interpreting the oVEMP results.

Acoustic, mechanical and galvanic stimulation modes elicit ocular vestibular-evoked myogenic potentials

OBJECTIVEnThis study compared the characteristic parameters of ocular vestibular-evoked myogenic potentials (oVEMPs) elicited by the air-conducted sound (ACS) and bone-conducted vibration (BCV) stimulation modes as well as the galvanic vestibular stimulation (GVS) mode.nnnDESIGNnFifteen healthy subjects underwent oVEMP tests using ACS (127 dBSPL), BCV (142dB force level), and GVS (5mA) modes. The response rate, latencies of nI and pI, nI-pI interval and amplitude were measured for each mode and compared among modes.nnnRESULTSnAll 15 healthy subjects (30 ears) had 100% response rates in both BCV- and GVS-oVEMPs, exhibiting a response rate significantly higher than 80% in ACS-oVEMPs. The mean nI latency was the shortest in the GVS mode, followed by BCV and then ACS modes. The variation among the latencies of the three modes was significant. Likewise, the mean nI-pI amplitudes in ACS-, BCV- and GVS modes varied significantly. However, the mean nI-pI interval did not differ significantly among the three modes.nnnCONCLUSIONSnAmong the ACS (127 dBSPL), BCV (142dB force level), and GVS (5mA) modes, the BCV mode yields a 100% response rate and the largest nI-pI amplitude of oVEMPs.nnnSIGNIFICANCEnThe oVEMPs in ACS and GVS modes may help to differentiate the saccular from the retro-saccular lesions. If ACS-oVEMPs are normal, then oVEMPs in BCV and GVS modes can distinguish between utricular and retro-utricular disorders. Restated, oVEMPs in ACS, BCV, and GVS modes may promote the topographical delineation of the lesion site of the otolithic-ocular reflex pathway.

Feasibility of the simultaneous ocular and cervical vestibular-evoked myogenic potentials in unilateral vestibular hypofunction

OBJECTIVEnThis study compared the results of combined and individual ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) tests in healthy subjects and patients with unilateral vestibular hypofunction to confirm the effectiveness of the combined oVEMP and cVEMP test.nnnMETHODSnTwenty healthy volunteers and 12 patients with unilateral vestibular hypofunction underwent individual oVEMP and cVEMP tests in a random order, and combined oVEMP and cVEMP test on another day.nnnRESULTSnTwenty healthy subjects had 100% response rates for oVEMPs and cVEMPs in both individual and combined stimulation modes. Significant positive correlations exist between individual and combined oVEMPs/cVEMPs in terms of latencies and amplitudes. In 12 patients with unilateral vestibular hypofunction, differences in abnormal percentages of oVEMPs or cVEMPs were non-significant. Additionally, the characteristic parameters of oVEMP/cVEMP among ears of healthy subjects, good and pathological ears of patients with unilateral vestibular hypofunction did not differ significantly, regardless of whether the individual or combined mode was used.nnnCONCLUSIONSnThe combined oVEMP and cVEMP test generates similar information to that obtained by individual mode, regardless of whether subjects are healthy or have unilateral vestibular hypofunction.nnnSIGNIFICANCEnSimultaneous oVEMP and cVEMP tests may be a convenient screening tool for assessing crossed vestibulo-ocular reflex and ipsilateral sacculo-collic reflex, which definitely shortens the diagnostic test time. Thus, it may favor the large diffusion of these techniques.