Vestibular Evoked Myogenic Potentials Amplitudes Research Articles

Impaired Vestibulo-Ocular Reflex on Video Head Impulse Test in Superior Canal Dehiscence: "Spontaneous Plugging" or Endolymphatic Flow Dissipation?

Surgical plugging of the superior semicircular canal (SSC) represents an effective procedure to treat disabling symptoms in superior canal dehiscence (SCD), despite resulting in an impaired vestibulo-ocular reflex (VOR) gain for the SSC. On the other hand, SSC hypofunction on video head impulse test (vHIT) represents a common finding in patients with SCD exhibiting sound/pressure-induced vertigo, a low-frequency air-bone gap (ABG), and enhanced vestibular-evoked myogenic potentials (VEMPs). "Spontaneous canal plugging" has been assumed as the underlying process. Nevertheless, missing/mitigated symptoms and/or near-normal instrumental findings would be expected. An endolymphatic flow dissipation has been recently proposed as an alternative pathomechanism for SSC VOR gain reduction in SCD. We aimed to shed light on this debate by comparing instrumental findings from 46 ears of 44 patients with SCD exhibiting SSC hypofunction with post-operative data from 10 ears of 10 patients with SCD who underwent surgical plugging. While no difference in SSC VOR gain values was found between the two groups (p = 0.199), operated ears developed a posterior canal hypofunction (p = 0.002). Moreover, both ABG values (p = 0.012) and cervical/ocular VEMP amplitudes (p < 0.001) were significantly higher and VEMP thresholds were significantly lower (p < 0.001) in ears with SCD compared to operated ears. According to our data, canal VOR gain reduction in SCD should be considered as an additional sign of a third window mechanism, likely due to an endolymphatic flow dissipation.

Comparison of clinical characteristics and vestibular function test results in patients with vestibular migraine and Menière’s disease

ObjectivesThe differentiation between Vestibular Migraine (VM) and Meniere's Disease (MD) is difficult because of overlapping symptoms. The study aimed to compare the clinical characteristics and vestibular function test results between VM and MD patients. MethodsSeventy-one patients with definite VM and 31 patients with definite unilateral MD were included. All patients received Caloric Test (CT), Video Head Impulse Test (vHIT) and Vestibular Evoked Myogenic Potential (VEMP) test within 7 days after visiting the hospital. Results of these tests were compared between groups. ResultsMost VM patients (64.0%) experienced spontaneous internal vertigo, while most MD patients (66.7%) experienced spontaneous external vertigo. MD patients had more severe vestibular symptoms and autonomic responses compared to VM patients during attacks (p = 0.03, p = 0.00, respectively). The nystagmus intensity of CT-induced was greater in VM patients than in MD patients (p = 0.003). More VM patients had CT intolerance and Central Positional Nystagmus (CPN) compared to MD patients (p = 0.002, p = 0.006, respectively). More MD patients had CT(+) and vHIT saccades wave compared to VM patients (p < 0.001, p = 0.002, respectively). The non-elicitation rate of cervical VEMP was higher, and the ocular VEMP amplitudes were lower in MD patients than in VM patients (p = 0.002, p = 0.018). ConclusionsVestibular symptoms during attacks combined with the results of vestibular function tests may be used to differentiate between VM and MD. The diverse nature of vestibular symptoms (especially internal vertigo), history of motion sickness and CT intolerance may provide clues to the diagnosis of VM, whereas spontaneous external vertigo, CT(+) with vHIT(-), and the presence of saccades may provide clues to the diagnosis of MD. Level of evidence4.

Stability of Vestibular Testing in Children With Hearing Loss.

The purpose of this study was to evaluate the stability of rotary chair, video head impulse test (vHIT), and vestibular evoked myogenic potential (VEMP) responses in children with normal hearing (NH) and children with cochlear implants (CIs). Retrospective analysis of 66 children (33 males, M age = 11.4 years, range: 3-18 years) seen in a tertiary clinic and/or research laboratory who completed rotary chair, VEMP, and vHIT across two test sessions between 2012 and 2019. The stability of these measures was compared between two groups: children with NH (n = 35) and children with CI (n = 31). For each outcome, the session difference was calculated by subtracting Session 1 from Session 2. For rotary chair (gain and phase) and vHIT (gain), linear mixed-effects models revealed that there were no significant interactions or main effects for group (CI vs. NH), time between session, gender, or age on the session difference, suggesting that the outcomes of these measures are stable across sessions. For cervical and ocular VEMP amplitude, there was a significant interaction between group and time between sessions on the session difference. Specifically, children with NH demonstrated larger amplitudes at Session 2, whereas children with CI demonstrated smaller amplitudes at Session 2. Next, test findings were classified as normal, unilaterally abnormal, or bilaterally abnormal for Sessions 1 and 2. Misclassification was defined as a mismatch of classification between sessions. Rotary chair and vHIT had the fewest misclassifications, whereas cervical VEMPs had the most misclassifications in children with CI and ocular VEMPs had the most misclassifications in children with NH. Misclassifications in children with CI were mostly consistent with progressive vestibular loss, whereas misclassifications in children with NH were mostly consistent with improved vestibular function. Stability and misclassification rates varied between tests and groups. Overall, rotary chair and vHIT outcomes were stable in both groups; however, VEMPs differentially changed between groups, improving in children with NH and declining in children with CI. Furthermore, despite relative stability, some children with CI evidenced progressive vestibular loss on all measures suggesting that vestibular testing should be completed serially due to the possibility of progression.

Effect of Electrode Montage on 500-Hz Tone Burst Evoked Masseter Vestibular Evoked Myogenic Potential.

Masseter vestibular evoked myogenic potentials (VEMPs) are short-latency myogenic responses obtained in response to electric or acoustic stimulation. It is a relatively newer test that helps assess the vestibulo-trigeminal pathway, thereby gaining more interest in brainstem pathologies like Parkinsonism, multiple sclerosis, and idiopathic random eye movement disorders. The purpose of the study was to compare the effect of zygomatic versus mandibular reference montage on the latency and amplitude of masseter VEMP (mVEMP) using a 500-Hz tone burst stimulus. Twenty healthy participants in the age range of 18-29 years, with no complaints of vestibular signs and symptoms, were recruited for the study. VEMP was recorded for all the participants using 500-Hz tone burst stimuli in zygomatic electrode montage and mandibular electrode montage. mVEMP was recorded in both ipsilateral and contralateral modes. The Wilcoxon signed-ranks test revealed no significant difference between the zygomatic and mandibular montage for both the latency and amplitude parameters (p > .05). This study revealed no significant difference in p11 and n21 latencies as well as p11-n21 rectified amplitude between zygomatic and mandibular montage using a 500-Hz tone burst stimulus in young adults. Hence, utilizing a 500-Hz tone burst, mVEMP can be recorded in zygomatic and mandibular electrode montage.

Weak Vestibular Response in Persistent Developmental Stuttering

Vibrational energy created at the larynx during speech will deflect vestibular mechanoreceptors in humans (Todd et al., 2008; Curthoys, 2017; Curthoys et al., 2019). Vestibular-evoked myogenic potential (VEMP), an indirect measure of vestibular function, was assessed in 15 participants who stutter, with a non-stutter control group of 15 participants paired on age and sex. VEMP amplitude was 8.5 dB smaller in the stutter group than the non-stutter group (p = 0.035, 95% CI [−0.9, −16.1], t = −2.1, d = −0.8, conditional R2 = 0.88). The finding is subclinical as regards gravitoinertial function, and is interpreted with regard to speech-motor function in stuttering. There is overlap between brain areas receiving vestibular innervation, and brain areas identified as important in studies of persistent developmental stuttering. These include the auditory brainstem, cerebellar vermis, and the temporo-parietal junction. The finding supports the disruptive rhythm hypothesis (Howell et al., 1983; Howell, 2004) in which sensory inputs additional to own speech audition are fluency-enhancing when they coordinate with ongoing speech.

Wideband tympanometry in ears with superior canal dehiscence before and after surgical correction

Objectives Wideband tympanometry (WBT) has been shown to be sensitive to mechanical changes in the ear. This study investigated the effect of surgical correction of superior canal dehiscence (SCD) on WBT (i.e. absorbance and middle ear resonance frequency) compared to those on common surgical outcomes such as symptom resolution, vestibular evoked myogenic potentials (VEMP), and hearing thresholds. Study sample and study design Seven patients (eight ears with SCD) who underwent surgical correction of SCD underwent WBT in addition to pure-tone audiometry and VEMP assessment. Results Postoperatively, all ears showed normalised/decreased absorbance at low frequencies and slightly enhanced absorbance in the middle frequency range (7/8 ears). The middle ear resonance frequency, which was initially lower than normal in most patients, increased in 6/8 operated ears, and decreased in two ears with no/partial symptom relief. In comparison, complete symptom control was observed in 6/8 operated ears, VEMP amplitudes reduced or normalised in all ears, and hearing thresholds remained stable or improved in 6/8 ears and worsened in two ears. Conclusions Surgery seems to change the response to WBT in patients with SCD. The results of WBT may represent mechanical changes induced by SCD, and should be considered when evaluating surgical outcomes.

Ocular and cervical vestibular evoked myogenic potentials elicited by air-conducted, low-frequency sound.

Sound is not only detected by the cochlea, but also, at high intensities, by the vestibular system. Acoustic activation of the vestibular system can manifest itself in vestibular evoked myogenic potentials (VEMPs). In a clinical setting, VEMPs are usually evoked with rather high-frequency sound (500 Hz and higher), despite the fact that only a fraction of saccular and utricular hair cells in the striolar region is available for high-frequency stimulation. As a growing proportion of the population complains about low-frequency environmental noise, including reports on vestibular symptoms, the activation of the vestibular system by low-frequency sound deserves better understanding. We recorded growth functions of oVEMPs and cVEMPs evoked with air-conducted sound at 120 Hz and below. We estimated VEMP thresholds and tested whether phase changes of the stimulus carrier result in changes of VEMP amplitude and latency. The VEMP response of the otholith organs to low-frequency sound is uniform and not tuned when corrected for middle ear attenuation by A-weighting the stimulus level. Different stimulus carrier phases result in phase-correlated changes of cVEMP latencies and amplitudes. VEMPs can be evoked with rather low-frequency sound, but high thresholds suggest that they are unlikely to be triggered by environmental sounds.

Predictive Value of Vestibular Evoked Myogenic Potentials in the Diagnosis of Menière's Disease and Vestibular Migraine.

To explore the usefulness of vestibular evoked myogenic potentials (VEMPs) in the diagnosis of Menière's disease (MD) and vestibular migraine (VM). Retrospective cohort. Multidisciplinary neurotology clinic. Definite MD and definite VM patients between January, 2015 and May, 2017, as well as healthy volunteers. Cervical and ocular VEMP (cVEMP and oVEMP) testing. VEMP response, amplitude, and latency. Twenty five definite MD, 34 definite VM, and 13 control subjects were analyzed. MD affected ears had significantly lower cVEMP (p = 0.007) and oVEMP (p < 0.001) amplitudes than control ears. VM ears had significantly lower oVEMP (p = 0.001), but not cVEMP (p = 0.198) amplitudes than control ears. MD affected ears, but not VM ears, had significantly more absent cVEMP (25.9% versus 0%, p = 0.005) and oVEMP responses (40.7% versus 0%, p < 0.001) than control ears. oVEMP latency was significantly shorter for both MD affected (p < 0.001) and VM ears (p < 0.001) than control ears. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated using a neurotology clinic MD prevalence of 7.9% in dizzy patients. A present cVEMP or oVEMP both have more than 93% chance of ruling MD out in the tested ear, while a cVEMP amplitude more than 54.9 μV or oVEMP amplitude more than 5.1 μV both have more than 94% of ruling out MD in the tested ear. Despite some overlap in VEMP results between MD and VM, when the diagnosis is uncertain between the two disorders due to symptomatic overlap and nonspecific audiometric data, VEMPs can be helpful in guiding treatment toward one disease entity or the other until more evidence points to a definitive diagnosis.

Vection in virtual reality modulates vestibular-evoked myogenic potentials.

The popularity of virtual reality (VR) has increased rapidly in recent years. While significant technological advancements are apparent, a troublesome problem with VR is that between 20% and 80% of users will experience unpleasant side effects such as nausea, disorientation, blurred vision and headaches-a malady known as Cybersickness. Cybersickness may be caused by a conflict between sensory signals for self-motion: while vision signals that the user is moving in a certain direction with certain acceleration, the vestibular organs provide no corroborating information. To resolve the sensory conflict, vestibular cues may be down-weighted leading to an alteration of how the brain interprets actual vestibular information. This may account for the frequently reported after-effects of VR exposure. Here, we investigated whether exposure to vection in VR modulates vestibular processing. We measured vestibular-evoked myogenic potentials (VEMPs) during brief immersion in a vection-inducing VR environment presented via head-mounted display. We found changes in VEMP asymmetry ratio, with a substantial increase in VEMP amplitude recorded on the left sternocleidomastoid muscle following just one minute of exposure to vection in VR. Our results suggest that exposure to vection in VR modulates vestibular processing, which may explain common after-effects of VR.

Effects of stimulus conditions on vestibular evoked myogenic potentials in healthy subjects

Background: Characteristics of vestibular evoked myogenic potentials (VEMPs) depend on stimulus conditions.Objective: To determine the optimal stimulus conditions for cervical and ocular VEMPs.Methods: Participants were 23 healthy subjects. We compared air-conducted cervical and ocular VEMPs elicited by various tone-burst conditions (frequencies 500–1,000 Hz, rise/fall times 1–2 ms, and plateau times 0–6 ms) with an intensity of 105 dB normal hearing level. Effects of simultaneous contralateral masking noise on VEMPs were also evaluated.Results: The largest cervical VEMP amplitudes were elicited by 500–750 Hz and 2–6 ms plateau time-tone-bursts, and the largest ocular VEMP amplitudes by 750 Hz and 2–4 ms plateau time-tone-bursts. Repeatability of the latency was better at 1 ms than at 2 ms rise/fall time in both VEMPs. In both VEMPs, masking noise reduced amplitude, and in ocular VEMP, amplitudes were significantly larger at the left ear stimulation than the right.Conclusion: Optimal tone-burst stimulation for both VEMPs seemed to be 500–750 Hz frequency and 1/2/1 ms rise/plateau/fall time without contralateral masking noise. Ocular VEMP amplitudes from left ear stimulation were originally larger than those from right ear stimulation.

Vestibular Evoked Myogenic Potentials After Epleys Manoeuvre Among Individuals with Benign Paroxysmal Positional Vertigo.

VEMP abnormalities in individuals with BPPV are often reported to be associated with utricle and saccule degeneration. The aim of the present study is to assess the frequency of VEMP abnormalities using vestibular evoked myogenic potentials in individuals with Posterior canal Benign Paroxysmal Positional Vertigo (BPPV) after Epley's manoeuvre. 36 individuals (36 ears) with definite posterior canal BPPV and 36 healthy controls were considered for the present study. All the them underwent otoscopic examination, Dix-Hallpike manoeuvre to diagnose posterior canal BPPV. Further Audiological Evaluation including pure tone audiometry was carried out to rule out vestibular disorders associated with hearing loss. Epley's manoeuvre was performed on all individuals with BPPV by an experienced otorhinolaryngologist. Cervical and Ocular Vestibular Evoked Myogenic Potentials (VEMP) were used to investigate the saccule and utricle functions following Epley's manoeuvre. Cervical VEMP and ocular VEMP abnormalities were observed in 8/36 (22.22%) and 18/36 (50%) affected ears with BPPV respectively. Cervical VEMP responses were reduced in amplitude among 1/36 (2.77%) and absent in 7/36 (19.44%) of affected ears with BPPV. Ocular VEMP responses were reduced in amplitude on 11/36 (30.55%), followed by absent responses in 5/36 (13.88%) ears with BPPV. Two patients with posterior canal BPPV i.e., 4/64 (5.55%) ears had bilateral absence of ocular VEMP responses. Two ears with BPPV 2/36 (5.55%) had absence of both cervical and ocular VEMP responses in BPPV affected ear. T test showed significant difference (p < 0.01) in the amplitude of ocular VEMP among posterior canal BPPV individuals when compared to cervical VEMP. The present study highlights individuals with Posterior canal BPPV may have otoconia dislodgement or macular degeneration of utricle, saccule, both utricle and saccule unilaterally, or bilaterally. VEMP may be useful in evaluating degeneration of both otolith organs associated with BPPV.

Vestibular evaluation of patients with unilateral subjective idiopathic tinnitus

Introduction: Objectives: To determine the value of vestibular evaluation by Vestibular Evoked Myogenic Potential (VEMP), and Videonystagmography (VNG) tests in patients with unilateral subjective idiopathic tinnitus (SIT). Method: Fifty patients with unilateral (SIT) (studied group) and 25 normal healthy volunteers (control group) were included in this study. The studied group was classified to tinnitus and non-tinnitus ears. VEMP and VNG tests was done to both groups in Audio-vestibular medicine unit of Assiut University Hospital from 2015 to 2018. Results: The results of both groups compared to each other and we found that VEMP response was present in 46 (92%) and absent in 4 (8%) in non-tinnitus ears, while response was present in 42 (84%) and absent in 8 (16%) in tinnitus ears among studied group. There is statistically significant difference in P1-N1 amplitude, P1 Latency and N1 Latency between tinnitus and non-tinnitus ears. Also, lower VEMP amplitude in tinnitus ears was recorded in comparison to non-tinnitus ears and control ear. Conclusion: Vestibular system can be affected in patients with unilateral SIT and this may be a potential detector of asymptomatic endolymphatic hydrops.

Vestibular evoked myogenic potential responses in Parkinson's disease.

- Our objectives were to determine the differences in the vestibular evoked myogenic potential (VEMP) responses in patients diagnosed with early staged idiopathic Parkinson's disease (PD) compared to the normal population and evaluate the vestibular system disorder causing balance-posture disorders. Second aim of this study was to investigate caloric test responses particularly in early staged PD compared to normal popu-lation. Thirty patients (14 females and 16 males; mean age, 60.6 ± 13.1 years) diagnosed with idiopathic PD and 28 healthy subjects (20 males and 8 females; mean age, 59.1 ± 6.4 years) were included. The patient and control groups were subdivided according to their age, gender and the patient group was subdivided according to onset time of the Parkinson symptoms, Hoehn-Yahr staging. The subgroups were compared for VEMP and caloric test responses. There were no significant differences between the study and control groups for right and left VEMP measurements. Patients over 60 years and under 60 years did not show significant differences in terms of right and left mean VEMP measurements. However, P1 amplitude was significantly lower in patients over 60 years old (P = .004). Gender, disease duration, BERG balance scale and Hoehn-Yahr stage had no effect on the VEMP amplitudes. There was no significant correlation with the side of Parkinsonian symptoms to the side of canal paresis (P = .566) and the side on which no VEMP response was obtained in caloric test. VEMP responses were not different between PD and healthy subjects. VEMP P1 amplitude was decreased with age in PD group. Canal paresis and symptoms side were not statistically correlated in caloric test.

Prevention of recurrent benign paroxysmal positional vertigo (BPPV)

Insufficient study of BPPV etiological factors results in a high rate of the disease recurrence, which impairs the patients’ life quality. The objective of this study was to improve the efficacy of BPPV treatment based on identification of predictive factors of disease recurrence by means of assessment of the severity of utriculus dysfunction and the study of calcium-phosphorus exchange disorders. We conducted a study of 25(OH) D level and registration of ocular BPPVs 7 days after the treatment in 98 patients with idiopathic posterior semicircular canal (PSC) BPPV (the index group, IG) and assessment of the effect of the detected changes on the frequency of the disease recurrences. To assess the prevalence of calcium metabolism disorders in the population, we arranged a control group (CG) of 30 healthy volunteers, identical in terms of socio-demographic characteristics. The prevalence of vitamin D deficiency (25 (OH)D less than 20 ng/ml) in the index group was 67% (n = 66), in the control group it constituted 10% (n = 3). The dependence of idiopathic BPPV incidence on 25(OH)D deficiency (chi-square test) was statistically significant (p &lt; 0.05), indicating that the 25(OH)D deficiency is a risk factor of idiopathic BPPV development. During registration of vestibular evoked myogenic potential (VEMP) 7 days after treatment, the P1N1 peaks of ocular VEMPs were not recorded on the affected side in 14(14%) patients, the clinically significant (&gt;40%) asymmetry in the amplitude of the ocular VEMP was identified in 25(26%) patients, the restoration of symmetry occurred in 59 (60%) patients. Within 12 months, the relapse occurred in 28 (28.5%) patients with BPPV. The relapse occurred in all patients with no P1N1 peaks of ocular VEMP on the 7th day after treatment (n = 14), in 56% (n = 13) of the patients maintaining clinically significant asymmetry (&gt;40%) of the ocular VEMP amplitude on the 7th day after treatment, in 2% (n = 1) patients with the restored symmetry of the ocular VEMP amplitude. The dependence of frequency of idiopathic BPPV recurrence development on existence of clinically significant asymmetry (&gt;40%) of the ocular VEMP amplitude on the 7th day after treatment (chi-square test) was statistically significant (p &lt;0.01). The combined determination of 25(OH)D level which is the etiological factor of idiopathic BPPV, and the functional state of the utriculus by means of ocular VEMP recording makes it possible to estimate the risk of a BPPV recurrence and to develop the preventive measures of the disease recurrence.

Simultaneous recording of cervical and ocular vestibular-evoked myogenic potentials.

To increase clinical application of vestibular-evoked myogenic potentials (VEMPs) by reducing the testing time by evaluating whether a simultaneous recording of ocular and cervical VEMPs can be achieved without a loss in diagnostic sensitivity and specificity. Simultaneous recording of ocular and cervical VEMPs on each side during monaural stimulation, bilateral simultaneous recording of ocular VEMPs and cervical VEMPs during binaural stimulation, and conventional sequential recording of ocular and cervical VEMPs on each side using air-conducted sound (500 Hz, 5-millisecond tone burst) were compared in 40 healthy participants (HPs) and 20 patients with acute vestibular neuritis. Either simultaneous recording during monaural and binaural stimulation effectively reduced the recording time by ≈55% of that for conventional sequential recordings in both the HP and patient groups. The simultaneous recording with monaural stimulation resulted in latencies and thresholds of both VEMPs and the amplitude of cervical VEMPs similar to those found during the conventional recordings but larger ocular VEMP amplitudes (156%) in both groups. In contrast, compared to the conventional recording, simultaneous recording of each VEMP during binaural stimulation showed reduced amplitudes (31%) and increased thresholds for cervical VEMPs in both groups. The results of simultaneous recording of cervical and ocular VEMPs during monaural stimulation were comparable to those obtained from the conventional recording while reducing the time to record both VEMPs on each side. NCT03049683.

92. Myogenic vestibular-evoked potentials: An extension of the assessment protocol

Vestibular-Evoked-Myogenic-Potentials (VEMPs) represent a muscular response following an intense acoustic stimulation. The cVEMPs explore a reflex arc (from saccule to the neck musculature) and usually are only recorded from sternocleidomastoideus (SCM). 1 They are non-invasive, well-tolerated, simple-to-perform and very useful in several diseases. The normal response is a biphasic complex P13/N23. We propose a more extensive protocol. We recruited 31 subjects (mean age ± SD:50.8 ± 19.0). VEMPs were recorded symmetrically and simultaneously through surface electromyography from SCM, splenius (SPL), trapezius (TRP) and orbicularis oculi (OO). The sensitivity was 20 μ V, band pass filter 20–2000 Hz, tone acoustic stimulus was monaural and binaural at 500 Hz, rate at 5.3 Hz. Three runs of 150 sweeps were averaged. The patients remained in clinostatic position with anterior neck flexion. Like the SCM cVEMP, the SPL and TRP cVEMP was characterized by a biphasic wave of muscle activity that began at ∼13 ms. Responses were consistent and repeatable. VEMPs latencies and amplitude showed a higher inter-reliability for the four muscles. The protocol offer a complementary target for cVEMP assessments. The simultaneous recording of oVEMPs and cVEMPs provide the evaluation of the ascending and descending vestibular pathways, allowing an extensive overview of brainstem function.

O160 The role of brainstem in syncope development

Objectives To investigate the role of brainstem in the development of vasovagal syncope. Methods Eighty-six multiple sclerosis (MS) patients were enrolled (61 females, mean age 32.01 ± 7.94). In all patients head-up tilt table test ocular and cervical vestibular evoked myogenic potentials (VEMPs) and brain and cervical spinal cord MRIs were performed. Additionally in 16 patients with syncope (8 females, mean age 28.43 ± 11.03,) VEMPs were performed. Results Syncope developed in 18 (20.9%) MS patients. Seventeen (94.4%) MS patients with syncope did not have brainstem and cervical spinal cord lesions (Chi square = 5.217, p = 0.022). Conduction block on VEMP was evident in 17 patients (19.8%). Only 2 out of 18 patients with syncope (11.1%) had conduction block on VEMP. A model was developed that predicted that only MS patients who do not have conduction blocks on VEMP and brainstem and cervical spinal cord MR lesions could develop syncope. The model accurately detected 83.3% of patients with syncope (15 of 18); Chi-Square = 4.980, p = 0.026. A significant difference in ocular VEMP amplitudes was found between MS patients with and without syncope and syncope patients ( p 0.001 ). Patients who developed syncope (regardless having or not MS), had significantly higher oVEMP amplitudes (10.21 ± 7.19 vs 7.85 ± 7.56, p = 0.034). Discussion Recent studies suggest that the initiation of syncope starts in the brainstem, and the purpose syncope is to salvage the brain’s blood supply. Conclusion Functional and structural integrity of the brainstem in MS are needed for syncope development. Significance Our results indicate the central role of the upper brainstem in the pathophysiology of syncope. This study was partially funded by the Installation Research project HRZZ UIP-11-2013-2622 of the Croatian Science Foundation.

Degeneration of the vestibular nerve in unilateral Meniere's disease evaluated by galvanic vestibular-evoked myogenic potentials.

The staging system of Meniere's disease utilizes audiograms to probe cochlear dysfunction. We explored the addition of galvanic vestibular-evoked myogenic potentials (VEMP) to further explore vestibular function. Seventy patients with unilateral Meniere's disease were enrolled in this study. Within 2weeks of diagnosis, all subjects underwent pure tone audiometry, cervical and ocular VEMP, and caloric test. The prevalence of abnormal tests and the VEMP characteristic parameters such as latencies and amplitudes were analyzed. In affected ears, the abnormal rate of acoustic cVEMPs, galvanic cVEMPs, vibratory oVEMPs and galvanic oVEMPs was 37%, 17%, 20%, and 9%, respectively. No significant differences existed in VEMP latencies and amplitudes between affected ears and unaffected ears. The impairment of otolithic organs was found to be more than that of vestibular afferents. The deterioration of the saccule was more than that of the utricle, whereas retrolabyrinthine degeneration of sacculo-collic reflex and vestibulo-ocular reflex was similar. This study is the first to use an electrophysiological test to evaluate the retrolabyrinthine function of patients with unilateral Meniere's disease.

Cervical and Ocular VEMP Testing in Diagnosing Superior Semicircular Canal Dehiscence.

Objective To determine the sensitivity and specificity of ocular and cervical vestibular evoked myogenic potentials (VEMPs) in the diagnosis of superior semicircular canal dehiscence (SCD) and to describe the VEMP response characteristics that are most sensitive to SCD and compare the findings to previous reports. Study Design Case series with chart review. Setting Two tertiary neurotologic referral centers. Subjects and Methods Cervical and ocular VEMP peak-to-peak amplitudes and thresholds from 39 adult patients older than 18 years with surgically confirmed SCD were compared with 84 age-matched controls. Results Using receiver operating characteristic (ROC) curves, cervical VEMP (cVEMP) amplitudes, cVEMP thresholds, and ocular VEMP (oVEMP) amplitudes had areas under the curve of 0.731, 0.912, and 0.856, respectively, all of which were statistically significant ( P < .0001). For cVEMP thresholds, at the clinical equivalent ≤85-dB normalized hearing level (nHL) threshold, the sensitivity and specificity were 97.3% and 31.3%, respectively. At the ≤70-dB nHL threshold, the sensitivity and specificity were 73.0% and 94.0%, respectively. For oVEMP amplitudes >12.0 µV, the sensitivity and specificity were 78.6% and 81.7%, respectively. Conclusion Data from this multicenter study suggest that both cVEMP thresholds and oVEMP amplitudes remain good diagnostic tests for identifying SCD, with each test dependent on a number of factors. The sensitivity and specificity of these individual tests may vary slightly between centers depending on testing parameters used.

The importance of vestibular evoked myogenic potentials for the assessment of the otolith function in the patients presenting with benign paroxysmal positional vertigo

The objective of the present study was to evaluate the otolith function in the patients presenting with idiopathic benign paroxysmal positional vertigo (pBPPV) attributable to the occlusion of the posterior semicircular canal (PSCC) of the inner ear with the use of vestibular evoked myogenic potentials (VEMP). Cervical (cVEMP) and ocular VEMP (oVEMP) were measured in 34 patients with idiopathic pBPPV before and 7 days after the treatment by means of reposition maneuvers. The results of the repeated Dix-Hallpike test performed 7 days after the repositioning maneuver were negative in 27 patients and positive in 7 patients. There was no statistically significant difference in the amplitude of cervical VEMP between the healthy and affected ears either before or after the repositioning treatment. The measurement of oVEMP revealed a reduction of the response amplitude on the affected side. The average values of the plnl on the healthy side were 12.84±1.09 and those on the affected side 4.62±0.69 (p<0,05). The successful repositioning treatment resulted in a significant increase of the oVEMP amplitude on the affected side (p<0,05). In the patients presenting with the persistent symptoms of pBPPV, the repositioning maneuvers did not cause an appreciable increase in the amplitude of oVEMP on the affected side (p<0.05). The results of the present study give evidence that pBPPV of the posterior semicircular canal is associated with the impairment of the function of the receptor structures of the utriculus and the preserved function of the succulus as suggested by the reduction of the oVEMP amplitude and clinically significant asymmetry of ocular VEMP on the affected side with intact cervical VEMP on both sides. The successful treatment of pBPPV of PSCC with the use of the liberatory maneuver results in the increase of the oVEMP amplitude on the affected side increases while the response asymmetry between both sides significantly decreases which indicates the repair of the utriculus otolith function.