The use of vestibular evoked myogenic potentials (VEMP) in the diagnosis of otolithic dysfunction of patients with obstructive sleep apnea: a survey of awareness and recognition of otorhinolaryngology medical staffs.

PURPOSE: To assess awareness and recognition of vestibular function tests in otorhinolaryngology medical staffs, especially the vestibular evoked myogenic potentials (VEMP) testing in patients with obstructive sleep apnea (OSA). METHODS: A survey was delivered via either email or a social media app. The medical staffs of the Chinese Medical Association of Otolaryngology Head and Neck Surgery from various branches were enrolled. Study data were collected and managed with an online data collection tool. RESULTS: A total of 1781 emails and 623 social media messages were sent to 2404 otorhinolaryngology medical staffs. One hundred and fifty-seven of them participated in the survey, including 24 via emails and 133 via the social media app. Regarding the knowledge of VEMP, only 59 (37.6%) of them agreed that OSA could be related to vertigo/dizziness/imbalance and 28 (17.8%) believed that OSA could result in VEMP abnormalities and would factor this in diagnosing the impairment of the vestibular function of OSA patients. A total of 7.6% of the respondents had never heard of the VEMP tests. Responses regarding the minimum age at which VEMP are possible ranged from younger than 6 months to greater than 18 years of age. Beliefs regarding the utility and reliability of VEMP varied, with 'unsure' being the most frequent response. In addition, only 17.8% of otolaryngologists indicated some access to the VEMP test. CONCLUSIONS: Knowledge and beliefs about the role of VEMP in diagnosing otolithic organ dysfunction caused by OSA in otorhinolaryngology vary widely. It is important for otorhinolaryngology medical staffs to learn the latest literatures and updated knowledge through continuing education.

Limitation of updated MR images on the vestibular hydrops in Meniere's disease.

PURPOSE: This study adopted the cervical and ocular vestibular-evoked myogenic potential (cVEMP and oVEMP) tests in Meniere's disease (MD) patients to correlate them with vestibular endolymphatic hydrops (EH) on MR images. METHODS: A total of 25 patients with unilateral definite MD identified by positive cochlear hydrops on MR images were enrolled. All patients underwent audiometry, cVEMP test and oVEMP test, followed by MR imaging for confirmation. RESULTS: A significantly declining sequence of abnormality rates in MD patients was identified from the audiometry (92%), cVEMP test (52%) to the oVEMP test (40%), which was consistent with a significantly decreasing order of prevalence of EH on MR images running from the cochlea (100%), saccule (56%) to the utricle (52%). The cVEMP test for detecting the saccular hydrops revealed a sensitivity of 62%, while the oVEMP test for assessing the utricular hydrops showed a sensitivity of 70%. However, correlating VEMP results with vestibular hydrops did not show any significant relationship. In addition, mean hearing level (MHL) at four frequencies (500, 1000, 2000, and 3000 Hz) of Grade I cochlear hydrops (51 ± 19 dB) did not significantly differ from Grade II cochlear hydrops (53 ± 19 dB). CONCLUSION: Limitations of the updated MR imaging for visualizing the hydrops comprised: (1) failure to correlate vestibular hydrops with VEMP results, and (2) failure to correlate grade of cochlear hydrops with MHL. The reason is probably because updated MR imaging fails to identify distorted contour of the cochlea/utricle/saccule. Further advanced technique using ultrahigh resolution of fine structures in the inner ear compartments is essential to promote a wider use of MR imaging.

Functional and Molecular Markers for Hearing Loss and Vertigo Attacks in Meniere's Disease.

Meniere's disease (MD) is one of the most complicated diseases in the otologic clinic. The complexity of MD is partially due to the multifactorial etiological mechanisms and the heterogenous symptoms, including episodic vertigo, hearing loss, aural fullness and tinnitus. As a result, the diagnosis of MD and differentiating MD from other diseases with similar symptoms, such as vestibular migraine (VM), is challenging. In addition, it is difficult to predict the progression of hearing loss and the frequency of vertigo attacks. Detailed studies have revealed that functional markers, such as pure tone audiometry (PTA), electrocochleography (ECochG), vestibular evoked myogenic potential (VEMP), caloric test, video head impulse test (vHIT) and magnetic resonance imaging (MRI) could help to evaluate MD with different hearing levels and frequency of vertigo attacks. Investigations of molecular markers such as autoimmunity, inflammation, protein signatures, vasopressin and circadian clock genes in MD are still underway. This review will summarize these functional and molecular markers, address how these markers are associated with hearing loss and vertigo attacks in MD, and analyze the results of the markers between MD and VM.

Vestibular evoked myogenic and auditory brainstem evoked potentials in a female migraine population.

Background and purpose:

The purpose of the present study was to evaluate ocular vestibular evoked myogenic potential (oVEMP), cervical vestibular evoked myogenic potential (cVEMP), and brainstem auditory evoked potential (BAEP) response characteristics and to understand the pathophy­siology of vestibular dysfunction in female migraineurs with vertigo symptoms. We also aimed to assess the electrophysiological di­­agnostic significance of the VEMP respon­ses in vestibular migraine (VM). 

23 patients with migraine without aura (MoA), 23 patients with VM, and 20 sex-and age-matched healthy controls, a total of 66 female participants were enrolled in this study. The outcome parameters were asymmetry ratios (ARs), amplitudes of oVEMP, cVEMP, N1P1, P13N23, and the respective latencies (mean ± SD). From the BAEP graphs, absolute and interpeak interval latencies of waves were analyzed. 

30.4% of the MoA group and 21.7% of the VM group had uni- or bilaterally absent cVEMP responses which were statistically significant only in the MoA group (p=0.035) in comparison to control group. Both groups displayed statistically insignificant absent or asymmetrical responses for oVEMP (13.1%). Cervical VEMP P13 and N23 latency, peak-to-peak amplitude, interaural latencies, and amplitude ARs did not show any significant difference between MoA and VM patients and healthy controls. No significant difference was detected among the three groups in the oVEMP and BAEP parameters.

Although absent cVEMP responses were more common in MoA and VM patients than in healthy individuals, the VEMP and BAEP test results should not be used in the differential diagnosis of VM and MoA. 

cVEMP and VAT for the diagnosis of vestibular migraine.

BACKGROUND: Although the diagnostic criteria of vestibular migraine (VM) have already been defined, various clinical manifestations of VM and the lack of pathognomonic biomarker result in high rate of misdiagnosis and mismanagement. A timely and accurate diagnosis tool for the evaluation of VM is highly needed. OBJECTIVE: The current study aims to investigate the potential feasibility of cervical vestibular evoked myogenic potential (cVEMP) and vestibular autorotation test (VAT) as a diagnosis tool for VM. METHODS: A total of 211 subjects were recruited into the current study with all subjects meeting the inclusion and exclusion criteria. The subjects were divided into 3 groups: healthy control group, general migraine group and VM group. Test of cVEMP and VAT was conducted in all the groups, and the generated data were statistically compared. RESULTS: Compared with the other two groups, cVEMP P13-N23 amplitudes of VM patients showed a significant decline. Mean latency values of the VM group had no significant difference in comparison with other groups. Asymmetry ratios showed increased level in VM patients compared to the control groups, without significant difference. VAT results showed that all the horizontal gain, horizontal phase, vertical gain and vertical phase differ from the other two groups to varying degrees at higher frequency. CONCLUSION: cVEMP and VAT have potential usage in the assessment of VM and can serve as powerful tool in diagnosis of VM.

Effect of Video Games on the Otolithic Reflex System.

BACKGROUND: Video gaming (VG) has since the 1980s become increasingly ubiquitous entertainment among the adolescents and young adults. Many young people expe-rienced dizzy spells, but not vertiginous episodes, after playing VG. OBJECTIVES: This study performed ocular vestibular-evoked myogenic potential (oVEMP) and cervical VEMP (cVEMP) tests in subjects before and after engaging on VG to investigate the effect of VG on the otolithic reflex system. METHODS: Twenty subjects who frequently played VG (>3 days per week) for more than 10 years were assigned to the long-term group. Another 20 subjects with engaging on VG <3 days per week or <10 years were assigned to the short-term group. Each subject underwent baseline oVEMP and cVEMP tests first, followed by playing VG for 1 h. Then, all subjects underwent the same paradigm. The "VG-year" is defined as frequency of VG playing within 1 week (day/week) multiplied by total length of VG engagement (year). RESULTS: Engagement on VG rarely affected the oVEMP responses for either short- or long-term players. In contrast, the response rates of cVEMP significantly declined from pre-VG period (80%) to post-VG period (58%) in the short-term group, but not in the long-term group. The cutoff value for predicting absent cVEMP in VG engagement is 21 VG-year. CONCLUSION: Short-term engagement on VG may result in temporary cVEMP loss, while permanent cVEMP loss could be identified in long-term VG players. The cutoff value for predicting absent cVEMP in VG engagement is 21 VG-year, indicating that damage to the sacculo-collic reflex system could be anticipated in a subject who has played VG at least 1 h per session, 7 days weekly for 3 years.

Evaluation of retrootolithic function using galvanic vestibular-evoked myogenic potentials in patients with benign paroxysmal positional vertigo.

PURPOSE: The purpose is to investigate possible vestibulopathy in patients with benign paroxysmal positional vertigo (BPPV), inner ear tests, including cervical and ocular vestibular-evoked myogenic potentials (cVEMPs and oVEMPs) via various stimulation modes, were adopted. METHODS: Fifty BPPV patients were enrolled in this study. All patients underwent pure tone audiometry, cVEMPs, oVEMPs, and caloric tests. The recurrence status, abnormal rates of inner ear tests, and the characteristic parameters of VEMPs, such as wave latencies and amplitudes, were analyzed. RESULTS: In affected ears, the abnormal rates of acoustic cVEMPs, vibratory oVEMPs, galvanic cVEMPs, and galvanic oVEMPs were 62%, 28%, 36%, and 14%, respectively. The abnormalities of acoustic cVEMPs were significantly larger than those of vibratory oVEMPs, and acoustic/vibratory VEMPs had significantly higher abnormal rates than the corresponding galvanic VEMPs. CONCLUSION: BPPV patients may have both otolithic and neural dysfunctions. Otolithic organ damage occurs more frequently than retrootolithic neural degeneration, and the saccular macula might have a greater extent of damage than the utricular macula.

Assessing the cervico-ocular reflex system via modifying the ocular vestibular-evoked myogenic potential test.

PURPOSE: The aim of this study was to devise a novel test for assessing the cervico-ocular reflex (COR) system via head vibration (termed h-COR) or neck vibration (termed n-COR) method. MATERIALS AND METHODS: Thirteen patients with complete loss of bilateral vestibulo-ocular reflex (VOR) showing oscillopsia were assigned to Group A, while 13 patients with bilateral VOR loss but no oscillopsia were Group B. Another 13 healthy elderly served as a control. The COR test was performed via modifying the ocular vestibular-evoked myogenic potential (oVEMP) test by tapping at the forehead with head rotation (h-COR) or at mid-dorsal neck with head straight (n-COR). RESULTS: Both h-COR and n-COR tests displayed similar cI-cII waveforms. None of the Group A or healthy elderly showed present h-COR, while 8% of Group A and 31% of the healthy elderly revealed present n-COR. In contrast, present h-COR and n-COR were elicited in 85 and 77% of Group B, respectively. Restated, significantly higher response rate of COR in Group B (without oscillopsia) than Group A (with oscillopsia) indicates that present COR is related to the alleviation of oscillopsia. CONCLUSIONS: Head vibration method (h-COR test) is superior to neck vibration method (n-COR test) for assessing the COR system.

Multiple sclerosis attack case presenting with pseudo-vestibular neuritis.

PURPOSE: Pseudo-vestibular neuritis is a clinical diagnosis for patients presenting with acute vestibular syndrome due to a central pathology. CASE REPORT: We reported a case of multiple sclerosis characterized by pseudo-vestibular neuritis. Our case was a 32-year-old male patient. The patient, who was diagnosed with multiple sclerosis in September 2019, came to the emergency clinic in January 2020 with the complaint of severe vertigo, vomiting-nausea. A newly developed demyelinating plaque was detected in the left vestibular nucleus in cranial MRI. The patient had no hearing loss. On examination of the patient, nystagmus findings supporting peripheral vestibular involvement were present on the left side. Neurologic examination showed left-sided hyperactive deep tendon reflexes, Achilles clonus, dysmetria, ataxia to the left and plantar reflex with extensor response on the left. Video head impulse test and cervical evoked myogenic potential tests were performed. Vestibular hypofunction was present on the left side. Steroid pulse therapy was administered as 1000 mg/day, i.v for 7 days. After treatment, his complaints decreased. In addition, there was an improvement in examination findings. CONCLUSION: Multiple sclerosis is shown to be an etiological factor in patients with pseudo-vestibular neuritis.

A model study of resonance effect on ocular vestibular-evoked myogenic potential.

BACKGROUND/PURPOSE: This study measured the acceleration magnitude using a dummy model filled with various air-material ratios to elucidate the mechanism of resonance effect on ocular vestibular-evoked myogenic potential (oVEMP). METHODS: With the percentages of air volume altered by filling various materials (water, glycerol, or ethanol) in an acrylic-made hollow spherical model, a minishaker was utilized to deliver vibration stimuli to the model. Then, acceleration magnitude of each model was measured. RESULTS: Since the air was most occupied at the upper part of the model (z-axis), acceleration magnitude along the z-axis was selected for comparison. An increasing trend of the z-axis acceleration magnitude ranging 0.110-0.759 g was identified in air-water model with air volume percentage ranged 40-100%. On the other hand, a significant increasing trend of acceleration magnitude along the z-axis (0.157-0.759 g) was noted in air-glycerol model with 80-100% of air volume. While in air-ethanol model, a significant increasing trend in acceleration magnitude along the z-axis ranged 0.121-0.759 g correlating with 40-100% of air volume. CONCLUSION: The mechanism for eliciting oVEMP is via the first-order bone vibration coupled with the second-order resonance effect. Both percentage of air volume (i.e. frontal sinus) and density of filling media (i.e. skull property) may contribute to the resonance effect, which then increases the acceleration magnitude so as to enhance the elicitation of oVEMP.

Effects of Age on Cervical Vestibular Evoked Myogenic Potentials and Ocular Vestibular Evoked Myogenic Potentials Using 750 Hz Tone Burst Stimuli among Healthy Adults.

Background: The vestibular evoked myogenic potentials (VEMPs) response characteristics depend on age, stimulus and individual anatomical differences. Therefore, normative data are required for accurate VEMPs interpretations. This cross-sectional study investigates VEMPs age-related changes among healthy adults using 750 Hz short alternating tone burst (TB) stimuli. Methods: Fifty adults aged between 23 years old and 76 years old with a mean of 51.56 (SD = 16.44) years old underwent air-conducted (AC) cervical VEMP (cVEMP) and head taps ocular VEMPs (oVEMPs) testing. Results: The cVEMPs and oVEMPs response rates reduced significantly at the age of 50-year-old and above. No significant age trends were observed for both cVEMPs and oVEMPs latencies and asymmetry ratios. However, amplitude reduced with increasing age for both cVEMPs, P < 0.001 and oVEMPs, P = 0.01. No significant differences in cVEMPs and oVEMPs latencies, amplitude or asymmetry ratios were identified between gender. Conclusion: To the best of our knowledge, this is the first published normative data for cVEMPs and oVEMPS in Malaysia and Southeast Asia, obtained among healthy adults aged between 23 years old and 76 years old. Health professionals in the region can use these findings as VEMPs normative references in their clinical settings.

Differences in responsiveness of intratympanic steroid injection for intractable vertigo in Meniere's disease.

OBJECTIVES: The efficacy of intratympanic steroid (ITS) injection for intractable Meniere's disease has been reported; however, its differences in responsiveness are not fully understood. This study investigated the clinical characteristics of patients who responded to ITS injection treatment. METHODS: This retrospective study included 32 patients with Meniere's disease who were unable to control frequent vertigo attacks despite conservative treatment for at least 3 months. They received an intratympanic injection of dexamethasone (3.3 mg/mL) in the affected side at least three times. We measured hearing threshold, subjective symptom scores, cervical and ocular vestibular evoked myogenic potential (cVEMP and oVEMP), and performed glycerol and bithermal caloric tests. RESULTS: Satisfactory control of vertigo for 1 year after the first round of injection was found in 18 patients (56.3%; the response group). However, the injections failed to control vertigo in the other 14 patients (43.8%; the non-response group), and they were then treated with middle ear micropressure therapy. The response group showed improvement in low-frequency hearing, whereas hearing acuity did not change in the non-response group. Significantly reduced amplitude of cVEMP on the affected side was found in 62.5% of patients in the response group; however, no patients in the non-response group showed reduced amplitude of cVEMP. CONCLUSIONS: ITS injection significantly improved the subjective symptoms for intractable Meniere's disease; however, the long-term effects were heterogeneous. Our results suggest that reduced amplitude in cVEMP is associated with the effectiveness of ITS injection treatment.

Elevated ocular VEMP responses in the absence of a superior semicircular canal dehiscence.

BACKGROUND: Vestibular evoked myogenic potentials (VEMPs) have an accepted role in the diagnosis of the superior semicircular canal dehiscence (SSCD) syndrome. The current impression is that ocular VEMPs (oVEMPs) are more sensitive than cervical VEMPs (cVEMPs) for detecting a SSCD and that oVEMP testing in response to air conducted sound provides an excellent screening test without risk of radiation exposure from computerized tomography (CT). AIMS/OBJECTIVES: To report on patients with elevated oVEMP amplitudes but without evidence for a SSCD on multiplanar CT imaging. MATERIAL AND METHODS: Retrospective chart review of all patients referred for vestibular function testing to our department. Patients with oVEMP peak-to-peak amplitudes ≥17 µν without evidence for a SSCD on imaging were evaluated. RESULTS: 26 patients had oVEMP peak-to-peak amplitudes ≥17 µν with no evidence of a SSCD on imaging. The most common diagnosis was Meniere's disease in those identified. CONCLUSION AND SIGNIFICANCE: oVEMPs can provide false positive results for diagnosis of a SSCD and an elevated oVEMP amplitude in itself is insufficient for diagnosis of a SSCD.

Static and dynamic otolith reflex function in people with Parkinson's disease.

PURPOSE: Parkinson's disease (PD) is a neurodegenerative disorder with possible vestibular system dysfunction. This study reports the transient and sustained functions of the otoliths and their reflex pathways in PD compared to healthy controls (HC) and determines if otolith function relates to previous fall history. METHODS: Forty participants with PD and 40 HC had their otolith function assessed. Transient saccular and utricular-mediated reflexes were assessed by cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs, respectively) elicited by air-conducted stimulus (clicks) and bone-conducted vibration (light tendon hammer taps). Static otolith function was assessed by the Curator Subjective Visual Vertical (SVV) test. RESULTS: Compared to HC, the PD group had significantly more absent cVEMP responses to both clicks (47.5% vs. 30%, respectively, p = 0.03) and taps (21.8% vs. 5%, respectively, p = 0.002). Only the PD group had bilaterally absent tap cVEMPs, this was related to previous falls history (p < 0. 001). In both groups, click oVEMPs were predominantly absent, and tap oVEMPs were predominantly present. The PD group had smaller tap oVEMP amplitudes (p = 0.03) and recorded more abnormal SVV responses (p = 0.01) and greater error on SVV compared to HC, p < 0.001. SVV had no relationship with VEMP responses (p = 0.14). CONCLUSIONS: PD impacts on cVEMP reflex pathways but not tap oVEMP reflex pathways. Bone-conducted otolith stimuli (taps) are more robust than air-conducted sound stimuli (clicks) for both o and cVEMPs. A lack of association between SVV and VEMP responses suggest that static and dynamic otolith functions are differentially affected in PD.

Multimodal control of neck muscles for vestibular mediated head oscillation damping during walking: a pilot study.

PURPOSE: It is still in question whether head oscillation damping during walking forms a part of the vestibular function. The anatomical pathway from the vestibular system to the neck muscles via the medial vestibulospinal tract (MVST) is well known but there is a lack of knowledge of the exact influence and modulation of each other in daily life activities. METHODS: (I) We fixed a head-neck unit of a human cadaver specimen in a steal frame to determine the required pitch-torque for a horizontal head position. The mean value of the acquired pitch-torque was 0.54 Nm. (II) On a motorized treadmill we acquired kinematic data of the head, the sternum and both feet by wireless 3D IMUs for seven asymptomatic volunteers. Subsequently three randomized task conditions were performed. Condition 1 was walking without any irritation. Condition 2 imitated a sacculus irritation using a standardized cVEMP signal. The third condition used an electric neck muscle-irritation (TENS). The data were analyzed by the simulation environment software OpenSim 4.0. RESULTS: 8 neck muscle pairs were identified. By performing three different conditions we observed some highly significant deviations of the neck muscle peak torques. Analysing Euler angles, we found during walking a LARP and RALP head pendulum, which also was strongly perturbated. CONCLUSION: Particularly the pitch-down head oscillation damping is the most challenging one for neck muscles, especially under biomechanical concerns. Mainly via MVST motor activity of neck muscles  might be modulated by vestibular motor signals. Two simultaneous proprioceptor effects might optimize head oscillation damping. One might be a proprioceptive feedback loop to the vestibular nucleus. Another might trigger the cervicocollic reflex (CCR).

Sudden deafness: a comparison between age groups.

OBJECTIVES: This study compared sudden deafness (SD) cases in 20-year age bands to investigate their causes and treatment outcome. DESIGN: Retrospective study. STUDY SAMPLES: 178 unilateral SD patients were divided into four 20-year age-groups, namely Groups I (aged 0-19 years, n = 6), II (aged 20-39 years, n = 33), III (aged 40-59 years, n = 63), and IV (aged 60-79 years, n = 76). METHODS: An inner ear test battery and/or serology assay were performed. RESULTS: Incidence of SD in relation to overall neurotological cases did not significantly differ among the four groups. Groups I and II showed two or three audiographic patterns, while Groups III and IV had six audiographic patterns indicating that the aetiology of Groups I and II may be of the same origin, while Groups III and IV had multiple aetiologies. The hearing improvement rate was significantly higher in Groups III (62%) and IV (62%) than in Groups I (16%) and II (33%). CONCLUSION: SD inevitably affects individuals of all ages. Significant differences in the audiographic patterns and speculative causes may account for various outcomes of treatment in each 20-year age band. Those SD patients aged 40-59 and 60-79 years showed significantly better treatment outcomes than those aged 0-19 and 20-39 years.

Bovine Satellite Cells Isolated after 2 and 5 Days of Tissue Storage Maintain the Proliferative and Myogenic Capacity Needed for Cultured Meat Production.

Cultured meat is an emerging alternative food technology which aims to deliver a more ethical, sustainable, and healthy muscle-tissue-derived food item compared to conventional meat. As start-up companies are rapidly forming and accelerating this technology, many aspects of this multi-faceted science have still not been investigated in academia. In this study, we investigated if bovine satellite cells with the ability to proliferate and undergo myogenic differentiation could be isolated after extended tissue storage, for the purpose of increasing the practicality for cultured meat production. Proliferation of bovine satellite cells isolated on the day of arrival or after 2 and 5 days of tissue storage were analyzed by metabolic and DNA-based assays, while their myogenic characteristics were investigated using RT-qPCR and immunofluorescence. Extended tissue storage up to 5 days did not negatively affect proliferation nor the ability to undergo fusion and create myosin heavy chain-positive myotubes. The expression patterns of myogenic and muscle-specific genes were also not affected after tissue storage. In fact, the data indicated a positive trend in terms of myogenic potential after tissue storage, although it was non-significant. These results suggest that the timeframe of which viable myogenic satellite cells can be isolated and used for cultured meat production can be greatly extended by proper tissue storage.

Is There Any Effect of Subjective Tinnitus on Vestibular Evoked Myogenic Potentials.

Idiopathic subjective tinnitus has a complex pathophysiology in which not only cochlear and central classical auditory pathways but also nonclassical auditory pathways of different parts of the brain are involved. Vestibuloocular and vestibulocollic pathways are the central projections of utricle and saccule used in the vestibular evoked myogenic potential (VEMP) test. Aim of this study was to investigate the effects of idiopathic subjective tinnitus on vestibuloocular and vestibulocollic pathways via VEMP. We prospectively analyzed 30 unilateral idiopathic subjective tinnitus patient's cervical, ocular VEMP tests, tinnitus handicap index scores, symptom duration and compared with contralateral ear and 35 healthy volunteers. The latencies and amplitudes of P1 and N1 waves were recorded and pathologic wave criteria was calculated according to healthy volunteer's data. In cervical VEMP there were significant longer latencies of P1 and N1 waves with respect to contralateral ear and control group. In ocular VEMP test, N1 and P1 latencies and amplitudes were not significantly different. The percentages of pathologic wave of the tinnitus side were not significantly higher in both cervical VEMP and ocular VEMP tests with respect to contralateral side. Tinnitus handicap index scores and symptom duration had no relationship with latency and amplitude of VEMP tests. Although cervical VEMP P1 and N1 latencies were significantly longer, subjective tinnitus did not result in pathological alterations in the VEMP test. Presence of subjective tinnitus is not an influencing factor in the VEMP interpretation.

The vestibulo-masseteric reflex and the acoustic-masseteric reflex: a reliability and responsiveness study in healthy subjects.

The vestibulo-masseteric reflex (VMR or p11 wave), the acoustic-masseteric reflex (AMR or p1/n21 wave) and the mixed vestibulo-cochlear p11/n21 potential are responses of masseter muscles to sound that can be employed to evaluate brainstem function. This study was aimed at establishing the test-retest reliability and responsiveness of these reflex parameters according to the type of electrode configuration. Twenty-two healthy volunteers (M:F = 11:11; mean age 25.3 ± 5.2 years) participated in two testing sessions separated by one week. Zygomatic and mandibular montages were compared following unilateral and bilateral stimulations. For reliability purposes, intraclass correlation coefficient (ICC), coefficient of variation of the method error (CVME) and standard error of measurement (SEM) were calculated. The minimal detectable difference (MDD) was also determined as a measure of responsiveness. Both VMR (p11 wave) and AMR could be consistently evoked from test to retest, although the frequency rate was significantly higher (all p values ≤ 0.009) with zygomatic (VMR: 97.7-100%; AMR: 86.9-97.6%) than mandibular montage (VMR: 84.7-89.8%; AMR: 65.0-67.8%), with no significant differences between unilateral and bilateral stimulations. Good-to-excellent reliability and responsiveness (high ICC, low CVME, SEM and MDD scores) were detected for corrected amplitudes and peak latencies for all reflex responses, whereas raw amplitudes were associated to poor reliability. The reliability of the zygomatic montage proved superior to the mandibular montage for all reflex responses. Given their high test-retest consistency and capability to study different features of the reflex arch, both peak latencies and corrected amplitudes should be reported and considered in the interpretation of reflex testing results.

Cervical vestibular evoked myogenic potential testing for assessment of vestibular functions in cochlear implant patients.

This study aims to investigate the vestibular function status of cochlear implant patients using cervical vestibular evoked myogenic potential (cVEMP) testing and estimate the effects of cochlear implants on vestibular function. The cVEMPs of 50 cochlear implant patients were measured preoperatively, and at one and six months postoperatively. Then, implanted ears and non-implanted ears were compared in terms of p13/n23 wave response rates, latency, amplitude and threshold. Preoperatively, the binaural cVEMP response rate was 92%, while the cVEMP response rates of implanted ears vs. non-implanted ears at postoperative one and six months were 24% vs. 80% and 52% vs. 82%, respectively. No significant difference between implanted and non-implanted ears was found preoperatively, in terms of latent period, amplitude, or threshold. However, significant changes were found in amplitude and threshold for implanted ears after the operation, but not in latency. No significant postoperative change was found in amplitude, latent period, or threshold for non-implanted ears. Significant differences between implanted and non-implanted ears were found in both amplitude and threshold. Cochlear implants affect vestibular function, especially saccular function, and reduce the cVEMP amplitude and threshold of implanted ears.