Cervical and ocular vestibular evoked myogenic potentials are sensitive to stimulus phase

Sinusoidal forces with frequencies of 100 and 500 Hz and initial positive or negative polarities were delivered to the mastoids and Fz in normal subjects. We investigated whether the cVEMPs and oVEMPs evoked were sensitive to the polarity (phase) of vibration. With mastoid stimulation at 100 Hz, medial head acceleration produced cVEMPs with earlier latency (15.5 ms) than lateral acceleration (19.7 ms) and oVEMPs with later latency (13.8 ms) than lateral acceleration (10.6 ms). As the stimulus frequency increased, the difference in latency decreased, but was still present at 500 Hz. A similar pattern occurred following stimulation at Fz. Our results show that the initial direction of bone-conducted vibration affects both cVEMP and oVEMP properties even at relatively high frequencies.     

Superior canal dehiscence reveals concomitant unilateral utricular loss (UUL)

Conclusion: We report enhanced symmetrical cervical vestibular evoked myogenic potential (cVEMP) but asymmetrical ocular VEMP (oVEMP) responses in a patient with CT-verified bilateral superior semicircular canal dehiscence (SCD) but with acute vestibular syndrome. This implies that absence of unilateral utricular macula function alone is sufficient to cause symptoms of acute vertigo. Acute vertigo should not automatically be presumed to originate from semicircular canal dysfunction. Objectives: To identify the cause of an acute vertigo attack in a patient with bilateral SCD. Methods: The functional state of all peripheral vestibular sense organs was tested using the video head impulse test (vHIT) for all semicircular canals and VEMPs to air-conducted sound (ACS) or bone-conducted vibration (BCV) to test all otolith organs. The cVEMP tested mainly saccular function and the oVEMP mainly utricular function. Results: All semicircular canals showed normal function. The cVEMPs showed enhanced, but symmetrical saccular function. In contrast, oVEMPs showed an enhanced but asymmetric n10 component – it was greatly reduced beneath the left eye, implying decreased function in the right utricular macula. That result was confirmed using very high frequency stimuli which are effective in SCD: 4000 Hz BCV stimuli showed that oVEMP n10 was present beneath the right eye but absent beneath the left eye.     

oVEMPs and cVEMPs in patients with ‘clinically certain’ Menière’s disease

Objective: To measure ocular vestibular-evoked myogenic potentials (oVEMPs) and cervical vestibular-evoked myogenic potentials (cVEMPS) in Menière’s disease patients with confirmed cochlear hydrops and in the normal ears of volunteers.

Methods: oVEMPs and cVEMPs were measured in 18 patients with a symptomatic diagnosis of Menière’s disease and tone burst electrocochleographic confirmation of hydrops, and in the ears of 22 volunteers.

Results: Threshold measures: For cVEMP: no significant differences between Menière’s ears and controls; for oVEMP: significantly elevated thresholds in affected ears of Menière’s ears compared with their unaffected ears, but not with controls. Latency measures: cVEMP N1 peaks were significantly prolonged compared with the left and right ears of controls, but not with the non-affected ear. Amplitude measures: cVEMP P1N1 and N1P2 measures were significantly reduced compared with the right ear of controls, but not with the non-affected ear; For oVEMP, N2P2 amplitudes were significantly reduced compared with both ears of controls but not with the non-affected ear.

Conclusion: Abnormalities of oVEMPs and cVEMPs were found in 18 Menière’s disease patients who had an independent confirmation of cochlear hydrops. The overlap of the results from Menière’s patients compared with normal controls limits the use of VEMP abnormalities as a sole reliable diagnostic test for Menière’s disease.     

Brainstem lesion in benign paroxysmal vertigo children: Evaluated by a combined ocular and cervical vestibular-evoked myogenic potential test

Objective

This study utilized a combined ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) test in children with benign paroxysmal vertigo (BPV) to investigate whether the upper or lower brainstem is more frequently affected in BPV children.

Methods

Fifteen BPV children aged 4-14 years, and 15 age- and sex-matched healthy children were enrolled. All subjects underwent pure tone audiometry, stabilometry, and a combined oVEMP and cVEMP test using acoustic stimulation.

Results

All BPV patients displayed normal hearing and clear oVEMPs. However, 11 (73%) of 15 BPV patients had delayed cVEMPs, showing significant difference when compared with 100% normal cVEMPs in healthy children. The sway path and sway area in stabilometry were significantly different between BPV and healthy children, regardless of whether their eyes were open or closed. However, neither the sway path nor sway area correlated significantly with cVEMP results.

Conclusion

Normal oVEMPs in BPV children indicate an intact vestibulo-ocular reflex pathway, which travels through the upper brainstem. In contrast, delayed cVEMPs in BPV children reflect a retrolabyrinthine lesion along the sacculo-collic reflex pathway, which descends via the lower brainstem. Hence, the lower brainstem is more frequently affected than the upper brainstem in children with BPV.     

Clinical Testing of Otolith Function: Perceptual Thresholds and Myogenic Potentials

Cervical and ocular vestibular-evoked myogenic potential (cVEMP/oVEMP) tests are widely used clinical tests of otolith function. However, VEMP testing may not be the ideal measure of otolith function given the significant inter-individual variability in responses and given that the stimuli used to elicit VEMPs are not physiological. We therefore evaluated linear motion perceptual threshold testing compared with cVEMP and oVEMP testing as measures of saccular and utricular function, respectively. A multi-axis motion platform was used to measure horizontal (along the inter-aural and naso-occipital axes) and vertical motion perceptual thresholds. These findings were compared with the vibration-evoked oVEMP as a measure of utricular function and sound-evoked cVEMP as a measure of saccular function. We also considered how perceptual threshold and cVEMP/oVEMP testing are each associated with Dizziness Handicap Inventory (DHI) scores. We enrolled 33 patients with bilateral vestibulopathy of different severities and 42 controls to have sufficient variability in otolith function. Subjects with abnormal oVEMP amplitudes had significantly higher (poorer) perceptual thresholds in the inter-aural and naso-occipital axes in age-adjusted analyses; no significant associations were observed for vertical perceptual thresholds and cVEMP amplitudes. Both oVEMP amplitudes and naso-occipital axis perceptual thresholds were significantly associated with DHI scores. These data suggest that horizontal perceptual thresholds and oVEMPs may estimate the same underlying physiological construct: utricular function.     

同步检测眼性和颈性前庭诱发肌源性电位的可行性研究

目的 探讨同步检测眼性前庭诱发肌源性电位(ocular vestibular-evoked myogenic potential,oVEMP)和颈性前庭诱发肌源性电位(cervical vestibular-evoked myogenic potential,cVEMP)的可行性.方法 对20例正常人及23例梅尼埃病患者分别进行oVEMP和cVEMP同步检测和单独检测,两种检测方式所用仪器和坐姿相同,检测参数设置相同,分别比较两种检测方式下两组对象oVEMP和cVEMP的振幅、潜伏期、波间期及双侧耳不对称比.结果 正常人左、右耳的oVEMP及cVEMP的引出率、振幅、潜伏期、波间期与不对称比在两种形式同步检测与各方式单独检测之间无显著差异;两种方式同步检测时梅尼埃病患者的患耳及对侧耳的oVEMP及cVEMP引出率、振幅、潜伏期、波间期及不对称比与各方式单独检测的结果也无显著差异.结论 对正常人和梅尼埃病患者,oVEMP和cVEMP检测可同步进行,但检测参数应与单独检测时设置一致.     

Differentiating cerebellar and brainstem lesions with ocular vestibular-evoked myogenic potential test

This study applied both ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) tests in patients with cerebellar disorders to determine whether VEMP test can differentiate between cerebellar and brainstem lesions. A total of 12 patients with cerebellar disorder, including extended cerebellar lesion (involving the brainstem) in 8 and localized cerebellar lesion (excluding the brainstem) in 4, were enrolled in this study. All patients underwent caloric, visual suppression, and oVEMP and cVEMP tests via bone-conducted vibration stimuli. The abnormal rates for the caloric, visual suppression, and oVEMP and cVEMP tests were 62, 83, 88 and 75% in patients with extended cerebellar lesion and 0, 25, 0 and 0% in those with localized cerebellar lesion, respectively. The rate of abnormal oVEMP results significantly differed between the two groups, but caloric, visual suppression and cVEMP test results did not differ. In another ten healthy subjects, characteristic parameters of oVEMPs obtained under light and dark conditions did not significantly differ. In conclusion, ocular VEMP test can differentiate between cerebellar and brainstem lesions. Abnormal oVEMPs in patients with cerebellar disorder may indicate adjacent brainstem involvement.     

Characterizing the frequency tuning properties of air-conduction ocular vestibular evoked myogenic potentials in healthy individuals

Abstract

Objective: Inconsistencies regarding frequency tuning of ocular vestibular evoked myogenic potentials (oVEMP) prompted the present study to aim at characterizing frequency tuning of oVEMP in healthy individuals. Design: Normative study. Study sample: The study was conducted to obtain oVEMP responses from 54 healthy individuals in age range of 18–30 years. The responses were acquired for tone-bursts at octave and mid-octave frequencies from 250 to 2000 Hz from the inferior oblique muscle using contralateral electrode placement. The frequencies were compared for amplitude and threshold. Results: oVEMPs were present in 100% of individuals at or below the frequency of 1000 Hz. The responses had maximum amplitude and lowest thresholds at 500 Hz. There were at least two replicable peak-complexes namely n1-p1 and p1-n2. Both these complexes revealed tuning at 500 Hz. Comparison between the two peak-complexes revealed higher amplitudes and lower thresholds for p1-n2 complex. Conclusions: oVEMPs are tuned to 500 Hz for both peak-complexes, with p1-n2 being more robust. Future studies using the threshold of oVEMP may be better suited to use p1-n2 complex for this purpose, provided vestibular origin of the second complex is proved. Additionally, careful use of tuning property is recommended when evaluating pathological conditions.     

Inner ear deficits after chronic otitis media

Investigation of the causes of vestibular symptoms in patients with chronic otitis media (COM) faces frustration, mainly because the bithermal caloric test using tap water is generally contraindicated in perforated ears. This study utilized audiometry, ocular vestibular-evoked myogenic potential (oVEMP) test, and cervical VEMP (cVEMP) test to evaluate inner ear deficits after COM. A total of 85 COM patients (117 ears) underwent otoscopy, image study, audiometry, oVEMP test, and cVEMP test. Mean bone-conducted (BC) hearing threshold ≤25 dB was observed in 74 ears, 26–40 dB in 30 ears, and >40 dB in 13 ears. Restated, abnormal BC hearing threshold was identified in 43 ears (37 %). Percentages of abnormal cVEMP test, oVEMP test, and BC hearing threshold in 117 COM ears were 65, 62, and 37 %, respectively, exhibiting a significantly declining sequence in inner ear function. Furthermore, cVEMP/oVEMP test results were significantly correlated with BC hearing threshold, whereas no correlation existed between the cVEMP and oVEMP test results. In conclusion, the sequence of inner ear deficits after COM runs from the saccule/utricle to the cochlea and semicircular canals. Restated, in addition to BC hearing test, the cVEMP/oVEMP test may serve as a supplementary tool for early detection of inner ear involvement in COM patients.     

Ocular vestibular evoked myogenic potentials: frequency tuning to air-conducted acoustic stimuli in healthy subjects and Ménière's disease

Ocular vestibular evoked myogenic potentials (oVEMP) in response to 250-, 500- and 1000-Hz air-conducted short tone bursts were studied in 22 healthy subjects and 37 Ménière's disease patients. The goal of this study was to investigate normal tuning characteristics of the oVEMP and the possible oVEMP changes with respect to frequency dependence in Ménière's disease. In unilateral Ménière's disease patients, a distinction was made between affected ears and unaffected ears. It was found that in normal subjects, the oVEMP tunes to a stimulus frequency of 500 Hz, with the highest amplitude and lowest threshold at this particular frequency. Generally, Ménière's disease patients showed lower amplitudes and higher thresholds than normal subjects at all 3 stimulus frequencies in both the affected and the unaffected ear. Additionally, for ears affected by Ménière's disease, the best stimulus frequency was 1000 Hz. With the use of this altered tuning for these ears, we tried to find a criterion for distinguishing normal from Ménière's disease ears.     

Glycerol affects vestibular-evoked myogenic potentials and pure-tone hearing in patients with Ménière’s disease

Conclusion: The pure-tone audiometry results following glycerol administration indicated a positive effect on cochlear endolymphatic hydrops. Glycerol cervical vestibular-evoked myogenic potential (cVEMP) tests are a useful means of diagnosing saccular hydrops. There was no correlation between cVEMP and audiological results. Objective: To document the changes in pure-tone hearing outcomes and cVEMPs in patients with Ménière’s disease (MD) and 10 healthy volunteers before and after oral administration of glycerol. Methods: Twenty-nine study group subjects were chosen with complaints of vertigo. cVEMP testing and pure-tone hearing level testing were performed before and at 1, 2, and 3 h after administration of glycerol. Results: The means of the latencies, amplitudes, and difference ratio in 20 normal subject ears were determined. Based on these values, 9/29 MD-affected (MDA) ears (31%) had a unilaterally absent cVEMP. Compared with difference ratio values of the control groups there were significant differences in both latencies and amplitudes in MDA ears after glycerol administration. Before glycerol administration, there were significant differences between control and MDA ears on mean values of pure-tone hearing outcomes. Twenty patients in the MDA group showed significant pure-tone hearing outcomes after glycerol administration.     

Acute bilateral vestibulopathy with simultaneous involvement of both superior and inferior vestibular nerves

We report a case of acute vestibulopathy with the simultaneous involvement of both superior and inferior vestibular nerves on both sides. A 36-year-old female presented with dizziness, oscillopsia and a walking impairment subsequent to a high fever. Vestibular function tests including caloric testing, video head impulse testing (vHIT) and cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs) were performed. In the first examination, vHIT and caloric testing showed severe impairments in all three semicircular canals in each ear, and both cVEMPs and oVEMPs were absent on both sides. During a 1-year follow-up, the gain of vHIT gradually recovered by more than 0.5 to normal. cVEMPs also recovered to normal on both sides while oVEMPs remained absent on both sides. This is the first reported case of acute bilateral vestibulopathy with simultaneous involvement of both superior and inferior vestibular nerves on both sides. Repeated evaluation of vestibular function using vHIT, cVEMPs and oVEMPs is helpful to assess the time course of recovery in patients with vestibulopathy.     

Pathological eye movements influence on the recordings of ocular vestibular-evoked myogenic potential

Objective: This study investigated the influence of pathological eye movements on the recordings of ocular vestibulo-evoked myogenic potential (oVEMP).

Methods: Ten patients with pathological eye movements of non-vestibular origin (nine congenital nystagmus and one opsoclonus) who had negative MRI result were assigned to Group A. Another 20 vestibular neuritis (VN) patients with spontaneous nystagmus were assigned to Group B. Both groups underwent audiometry, and caloric, oVEMP and cervical VEMP (cVEMP) tests.

Results: In Group A, the caloric, oVEMP and cVEMP tests showed 40%, 55% and 50% abnormalities, respectively. In Group B (VN), caloric, oVEMP and cVEMP tests revealed 100%, 80% and 45% abnormalities on the lesion ears, and 0%, 40% and 0% abnormalities on the healthy (opposite) ears, respectively. The 40% oVEMP abnormality on the healthy ears may be due to recording failure from the presence of spontaneous nystagmus, since five of five VN patients showed normal oVEMPs on the healthy ears, one year after presentation.

Conclusions: Presence of pathological eye movements may affect the recordings of oVEMP. Thus, the oVEMP test is recommended to perform after acute vertiginous episode to exclude the influence of pathological eye movements on the oVEMP recordings.     

气导声刺激前庭诱发肌源性电位在正常儿童中的表现

目的 探讨研究正常儿童中气导声刺激诱发的眼性前庭诱发肌源性电位(oVEMP)和颈性前庭肌源性诱发电位(cVEMP)的各项参数指标,并对正常值进行统计学处理分析。 方法 选择4~10岁听力正常健康儿童52例,以500 Hz短纯音作为刺激音,分别行 oVEMP和cVEMP检测,记录左、右耳引出率及波形参数,并采用SPSS统计软件进行统计学处理分析。 结果 双耳皆未引出oVEMP 2例,单耳可引出oVEMP4例,oVEMP总体引出率为92%。双耳皆未引出cVEMP 2例,cVEMP总体引出率为96%。oVEMP与cVEMP的P1潜伏期分别为(17.07±0.89)ms、(15.55±1.58)ms;N1潜伏期分别为(12.39±0.91)ms、(23.10±2.29)ms;N1P1间期分别为(4.68±0.88)ms、(7.83±1.56)ms;oVEMP与cVEMP的振幅分别为(7.24±4.79)μV、(197.40±118.37)μV。双耳间oVEMP及cVEMP振幅不对称比分别为(19.03±12.50)%、(22.16±18.64)%。患儿左右耳的潜伏期,P1N1间期及振幅差异无统计学意义(P>0.05)。 结论 绝大部分正常儿童经气导声刺激可引出oVEMP与cVEMP。该检测患儿依从性高,可用来评估儿童前庭功能。此研究结果可为我国的儿童气导VEMP提供正常参考值范围。     

Influence of cochlear implantation on vestibular function

Conclusion Vestibular function in patients can be damaged following cochlear implantation. Therefore, assessing the pre-operative vestibular status, carefully choosing the side of implantation, and preserving function by using minimally invasive surgical techniques are important. Objectives The aim of this study was to assess the influence of cochlear implantation on vestibular function in patients with severe and profound sensorineural hearing loss, and to analyze a possible correlation between the changes in vestibular testing and post-operative vestibular symptoms. Methods Thirty-four patients were evaluated for vestibular function using the cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP, respectively), and 29 patients underwent caloric tests pre-operatively and 4 weeks post-operatively. Results Before surgery, the cVEMPs were recorded bilaterally in 22 patients, unilaterally in eight patients, and absent bilaterally in four patients. The oVEMPs were recorded bilaterally in 19 patients, unilaterally in six patients, and absent bilaterally in nine patients. After implantation, the cVEMPs were absent in 10 patients and the oVEMPs were absent in seven patients on the implanted side. Caloric tests demonstrated canal paresis in 17 patients, and normal responses were recorded in 12 of the 29 patients pre-operatively. There was a significant decrease post-implantation in the ear implanted, with the exception of two patients. Two patients presented with vertigo and another two patients reported slight unsteadiness post-operatively, but all symptoms resolved within 7 days. The impaired vestibular function did not correlate with vestibular symptoms, age, or gender. Function on the contralateral side remained unaffected.     

Frequency Tuning of the Cervical Vestibular-Evoked Myogenic Potential (cVEMP) Recorded from Multiple Sites along the Sternocleidomastoid Muscle in Normal Human Subjects

Frequency tuning of tone burst-evoked myogenic potentials recorded from the sternocleidomastoid muscle (cervical VEMP or cVEMP) is used clinically to assess vestibular function. Understanding the characteristics of cVEMP is important for improving the specificity of cVEMP testing in diagnosing vestibular deficits. In the present study, we analyzed the frequency tuning properties of the cVEMPs by constructing detailed tuning curves and examining their morphology and dependence on SCM tonic level, sound intensity, and recording site along the SCM. Here we report two main findings. First, by employing nine tone frequencies between 125 and 4,000 Hz, some tuning curves exhibited two distinct peaks, which cannot be modeled by a single mass spring system as previously suggested. Instead, the observed tuning is better modeled as linear summation of two mass spring systems, with resonance frequencies at ~300 and ~1,000 Hz. Peak frequency of cVEMP tuning curves was not affected by SCM tonic level, sound intensity, and location of recording site on the SCM. However, sharpness of cVEMP tuning was increased at lower sound intensities. Second, polarity of cVEMP responses recorded from the lower quarter of the SCM was reversed as compared to that at the two upper sites. While more studies are needed, these results suggest that cVEMP tuning is mediated through multiple generators with different resonance frequencies. Future studies are needed to explore implications of these results on development of selective VEMP tests and determine the nature of polarity inversion at the lower quarter of SCM.     

Ocular vestibular evoked myogenic potentials to air conduction (AC oVEMP): useful in clinical practice?

Cervical vestibular-evoked myogenic potential (cVEMP) and ocular VEMP (oVEMP) stimuli can be used to measure otolith function using air (AC) and bone conducted (BC) stimuli. Cervical VEMPs reflect saccular function and can be recorded using air conduction (AC), whereas oVEMPs reflect probably predominantly utricular function. Air- and bone-conducted vibration can be used, because AC oVEMP methodology seems to be fast and simple in clinical practice to measure otolith function. In this study we discuss the advantages and problems of AC oVEMP stimulation. AC oVEMP can be easily and quickly obtained within a few seconds. N10 (first negative peak) and p15 (first positive peak) latencies may be used as parameters for clinical interpretation but amplitude fluctuations are relatively large. For daily clinical use of VEMP visualization in a normogram seems feasible. Especially the AC oVEMP methodology (100 dB nHL, tone burst 500 Hz) is fast and efficient in clinical practice to measure otolith function, predominantly utricular function.     

原发性良性阵发性位置性眩晕患者前庭诱发肌源性电位检测的意义

目的：探讨检测眼肌前庭诱发肌源性电位（oVEMP）和颈肌前庭诱发肌源性电位（cVEMP）对单侧原发性良性阵发性位置性眩晕（BPPV）患者进行可能发病部位的定位诊断价值。方法：对52例单侧原发性BP-PV患者（BPPV组）和38例正常人（对照组）分别进行气导短纯音诱发的oVEMP和cVEMP检测,分析两种反射的引出率、潜伏期、振幅等数据。结果;BPPV组患侧oVEMP的引出率为46．15％,cVEMP的引出率为67．31％;其健侧oVEMP的引出率为48．08％,cVEMP的引出率为65．38％。对照组左侧oVEMP的引出率84．21％,cVEMP的引出率92．11％;右侧oVEMP的引出率为81．58％,cVEMP的引出率为94．74％。对照组双侧cVEMP和oVEMP的P1、N1潜伏期及N1-P1振幅值差异均无统计学意义。BPPV组和对照组cVEMP和oVEMP耳间振幅比及不对称率差异有统计学意义（P〈0．05）。结论：单侧原发性BPPV患者双侧前庭耳石器传导通路功能受损状况,可以通过oVEMP和cVEMP检测进行客观评估,并且oVEMP的异常率比cVEMP高。     

Effectiveness of different click stimuli in diagnosing superior canal dehiscence using cervical vestibular evoked myogenic potentials

Abstract Conclusion: Testing cervical vestibular evoked myogenic potential (cVEMP) in response to 90 dB nHL clicks can, in contrast to high-intensity 500 Hz tone bursts, be used as a screening test for superior canal dehiscence (SCD) syndrome. Objectives: cVEMP testing has its key clinical significance for evaluating saccular and inferior vestibular nerve function, but also for assessment of vestibular hypersensitivity to sounds in patients with SCD syndrome. The routine stimulus used in cVEMP testing is high-intensity 500 Hz tone bursts. The aim of the present study was to compare the high-intensity tone burst stimulation with less intense click stimulations for the diagnosis of SCD syndrome. Methods: cVEMP amplitudes in response to 500 Hz tone bursts and clicks were studied in 38 patients with SCD syndrome unilaterally. Results: cVEMP testing using high-intensity 500 Hz tone bursts did not consistently distinguish SCD patients. This nonfunctioning of high-intensity 500 Hz stimulation is most likely due to saturation. With 90 and 80 dB nHL clicks there is low risk for saturation and both these click stimulations were effective. Testing with both 80 and 90 dB nHL clicks did not have any significant advantage over just using 90 nHL dB clicks.