Masseter and cervical vestibular evoked myogenic potentials in individuals with auditory neuropathy.

OBJECTIVE: This study aimed to explore the functional integrity of vestibulo-masseteric and sacculo-collic reflex pathways in individuals with Auditory Neuropathy (AN). The study also aimed at finding the correlation between mVEMP and cVEMP response parameters for AN and healthy individuals. DESIGN: Standard group comparison research design. STUDY SAMPLE: Individuals with AN (n = 20); age-gender matched healthy individuals (n = 20) were recruited. Each participant underwent routine audiological evaluation; mVEMP and cVEMP testing. mVEMP and cVEMP were recorded using 500 Hz tone burst stimulus for all the participants. RESULTS: Most of the AN individuals had no mVEMP (ipsilateral & contralateral - 60%; bilateral - 50%) and cVEMP (60%) responses. There was no significant association (p > 0.05) between the duration of AN with mVEMP and cVEMP findings. However, a significant correlation (p < 0.05) was found for EMG rectified amplitude of mVEMP and cVEMP in AN. CONCLUSION: The results of this study suggested an impaired function of the vestibulomassteric and sacculocollic reflex pathways in individuals with AN. Vestibular evaluation should be included as a part of the regular test battery for individuals with AN.

Vestibular reflexes in essential tremor: abnormalities of ocular and cervical vestibular-evoked myogenic potentials are associated with the cerebellum and brainstem involvement.

This study utilized cervical vestibular-evoked myogenic potentials tests (cVEMP) and ocular vestibular-evoked myogenic potentials tests (oVEMP) to investigate the vestibulocollic and vestibuloocular reflex arcs and to evaluate cerebellar and brainstem involvement) in essential tremor (ET). Eighteen cases with ET and 16 age- and gender-matched healthy control subjects (HCS) were included in the present study. Otoscopic and neurologic examinations were performed on all participants, and both cervical and ocular VEMP tests were performed. Pathological cVEMP results were increased in the ET group (64.7%) compared to the HCS (41,2%; p > 0.05). The latencies of P1 and N1 waves were shorter in the ET group than in HCS (p = 0.01 and p = 0.001). Pathological oVEMP responses were significantly higher in the ET group (72.2%) compared to the HCS (37.5%; p = 0.01). There was no statistically significant difference in oVEMP N1-P1 latencies between groups (p > 0.05). Because the ET group had high pathological responses to the oVEMP, but not the cVEMP, the upper brainstem pathways may be more affected by ET.

Systematic review of the diagnostic value of hydrops MRI in relation to audiovestibular function tests (electrocochleography, cervical vestibular evoked myogenic potential and caloric test).

The objective of this systematic review is to compare the diagnostic value of endolymphatic hydrops (EH) magnetic resonance imaging (MRI) with audiovestibular function tests, including electro cochleography (ECochG), cervical vestibular evoked myogenic potential (cVEMP) and caloric tests for the diagnosis of definite Meniere's disease (DMD). An electronic search was performed in the PubMed, Embase and Cochrane databases in August 2022. Original studies which reported the efficacy of gadolinium MRI for diagnosis of DMD were compared with ECochG, cVEMP and caloric tests from 2007 to 2022 published in English. Two reviewers extracted the methodology and results of MRI and functional tests, assessing them independently. A modified version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used for the assessment of the quality and the risk of bias of each study. The proportion of DMD cases diagnosed by MRI hydrops vs corresponding functional tests were calculated and the relationship between MRI and functional tests were evaluated using the Cohen's Kappa test. Concerning the MRI, the proportion diagnostic of DMD was 0.67 by cochlear EH and 0.80-0.82 by vestibular EH. Regarding the functional test, the propotiojn diagnostic of DMD was 0.48 by ECochG, 0.76 by cVEMP and 0.65 by caloric test. The findings of this systematic review were that the vestibular EH on imaging most effectively assisted in diagnosing DMD. Among the functional tests, cVEMP was the second most effective test. The agreement between imaging and cVEMP was moderate (0.44), indicating a gap between the patients identified by the imaging and functional tests based on the relatively small number of patients.

Cochlear and vestibular involvement in children with IgA vasculitis.

In this study, our purpose is to evaluate cochlear and vestibular function in juveniles with IgA vasculitis using audiometry, distortion product otoacoustic emissions, and cervical vestibular evoked myogenic potential (cVEMP) tests. Forty children diagnosed with IgA vasculitis from the pediatry clinic and 40 age- and sex-matched healthy children were evaluated with distortion product otoacoustic emissions, audiometry, and cVEMP test in a tertiary hospital. The audiometry average values for both ears of the IgA vasculitis group and the control subjects were compared, and as a result, median 4.7-dB sensorineural hearing loss (SHL) was found for the IgA vasculitis group compared to the control group at 250 Hz and it was statistically significant (p < 0.001). An average of 6.4-dB SHL was detected at 8000 Hz (p < 0.001). There was a statistically significant difference among IgA vasculitis and control groups regarding measurement results of average p1-n1 latency time of both ears (0.9 ms (ms) increase, p = 0.035). In IgA vasculitis patients, the median amplitude difference of both ears' average p1 n1 was found to be 5.6 mV, statistically significantly decreased compared to the control group (p = 0.003). CONCLUSION: This study, firstly in literature, demonstrated that IgA vasculitis may have association with hearing loss and vestibular dysfunction in children. We think this might be due to autoimmune mechanisms. WHAT IS KNOWN: • Ig A vasculitis is a leukocytoclastic vasculitis with unknown etiology, involving the skin, joints, gastrointestinal system, kidneys, and rarely other organs. • No study has been reported for the cochlear and vestibular association of Ig A vasculitis in current literature. WHAT IS NEW: • This study demonstrated that Ig A vasculitis may have association with hearing loss in children. • This study also demonstrated that Ig A vasculitis may have association with vestibular dysfunction in children.

Comparison of cervical and ocular vestibular-evoked myogenic potential responses between tone burst versus chirp stimulation.

PURPOSE: To compare the effectiveness of chirp and tone burst stimuli in oVEMP and cVEMP testing for healthy adults METHODS: This study was conducted in 56 healthy volunteers (112 ears). Ocular and cervical VEMP (oVEMP, cVEMP) tests were performed for each participant using tone burst and chirp stimuli. VEMP response rates, latency of each peak (p1-n1, n1-p1), peak to peak amplitude (p1-n1 amplitude and n1-p1 amplitude), and rectified amplitudes were measured and compared between these two different stimuli. RESULTS: VEMP response rates with chirp stimuli are higher than the tone burst stimuli for both cVEMP and oVEMP tests (The difference was statistically significant for oVEMP, p = 0.001). Chirp stimuli have higher p1n1 amplitude and rectified amplitude and shorter p1and n1 latency then tone burst stimuli for cVEMP (p = 0.015, p = 0.007, p < 0.001, p < 0.001, respectively). Chirp stimuli also have higher n1p1 amplitude and shorter n1and p1 latency then tone burst stimuli for oVEMP (p = 0.006, p < 0.001, p < 0.001, respectively). CONCLUSION: The present findings show that the chirp stimulus triggers earlier VEMP responses with higher amplitudes than the tone burst stimulus during cVEMP and oVEMP testing. VEMP response rate with chirp stimulus is also higher than the tone burst. Therefore chirp stimulus can be used in VEMP testing as effectively as, if not more than, tone burst stimulus in clinical practice.

Recurrent vestibulopathy: are cVEMP, oVEMP and inner ear MRI useful to distinguish patients with Menière's disease and vestibular migraine?

PURPOSE: The aim of this study was to assess the rate of endolymphatic hydrops (EH) on MRI and the rate of otolithic dysfunction with cVEMP and oVEMP, in patients with recurrent vertigo such as Menière's disease (MD), vestibular migraine (VM) and vestibular Menière's disease (vMD). METHODS: In this retrospective study, we performed 3D-FLAIR sequences with delayed acquisition in 20 MD, 20 VM and 20 vMD patients. Each subject was then assessed for the presence of EH on MRI. All patients underwent pure-tone audiometry, cVEMP and oVEMP. RESULTS: In MD patients, EH was observed in 18 (90%) out of 20 patients while EH was observed in only 1 MV (5%) and 1 vMD (5%) patients. We found significant differences between groups for the presence of EH on MRI (p = 0.001). MD patients had significant higher PTA level (p < 0.001) and oVEMP impairment than MV and vMD (p = 0.08 and p = 0.06, respectively). However, no significant differences were observed for cVEMP impairment, either asymmetric ratio (p = 0.36) and 1000/500 ratio (p = 0.20). CONCLUSIONS: Concerning cVEMP, we observed no significant differences between VM, vMD and MD. However, we observed higher oVEMP impairment, PTA level and EH on MRI in MD patients. We believe that MRI could be used to differentiate MD from VM patients with cochlear symptoms. However, in cases of migraine associated with recurrent vertigo and without cochlear symptoms, we believe that MRI is not a useful tool to differentiate between VM and vMD.

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.

Outcomes of cVEMP and oVEMP in Individuals with Tinnitus and Normal Hearing.

PURPOSE: The purpose of the present study is to find the functions of vestibular reflexes in individuals' with normal hearing and tinnitus, to identify vestibular dysfunctions earlier, and helps with the management of the same. METHOD: The present study aimed to administer cVEMP and oVEMP to all the participants having a normal hearing with tinnitus (experimental group) and without tinnitus (Control group) and compared p13, n23 latencies and peak-to-peak amplitude of cVEMP; n10, p15 latencies of oVEMP and peak-to-peak amplitude between two groups and within tinnitus group. RESULTS: The present study stated that there is no statistically significant difference seen in cVEMP except n23 latency of bilateral tinnitus than control group. However, there is statistically significant difference in left ear p15 latency, left ear peak-to-peak amplitude, bilateral peak-to-peak amplitude between the two groups and Right Vs Left ear peak-to-peak amplitude in within the tinnitus group was seen in oVEMP. T-test was used to compare the latencies of p13, n23, and peak-to-peak amplitude of cVEMP and n10, p15 latencies and peak-to-peak amplitude of oVEMP between the experimental and control group and within the tinnitus group. CONCLUSION: There is no significant difference seen in cVEMP except n23 latency of bilateral tinnitus than control group and However, there is statistically significant difference in left ear p15 latency, left ear peak-to-peak amplitude, bilateral peak-to-peak amplitude between the two groups and Right Vs Left ear peak-to-peak amplitude in within the tinnitus group was seen in oVEMP and the current study concluded that the significant results with several parameters and no significant results with other parameters in cVEMP and oVEMP recording might be Presymptomatic tinnitus is regarded to occur in ears with normal hearing and abnormal VEMP, while asymptomatic tinnitus may occur in ears with normal VEMP. Tinnitus may be the first signs of secondary or delayed endolymphatic hydrops. If this is demonstrated to be accurate, we should anticipate that such patients will gradually develop other endolymphatic hydrops symptoms like SNHL and clinical vestibular dysfunction.

Vestibular involvement of PFAPA syndrome.

OBJECTIVE: PFAPA syndrome is derived from the initials of the English words of the findings that make up the syndrome ("Periodic Fever", "Aphthous Stomatitis", "Pharyngitis", "Adenitis"). This study aims to evaluate the vestibular system in patients with PFAPA syndrome by the cVEMP test and to give a general review of PFAPA syndrome in light of current literature. METHODS: In this prospective study, 30 patients aged 4-6 who were diagnosed with PFAPA in a tertiary pediatrics clinic, between January 2016 and February 2020 and 30 children of the same age group who applied to a tertiary otorhinolaryngology clinic for other reasons and proven to have no hearing or vestibular problems were included and in addition to routine physical examination, electromyographic activity of the sternocleidomastoid muscle surface was measured. RESULTS: We found that the amplitude difference between cVEMP p1-n1 in patients with PFAPA syndrome in both ears decreased compared to the healthy control group. CONCLUSION: Our study proves there is a vestibular system involvement of PFAPA syndrome. This study is the first in the literature to search the relationship between PFAPA and the vestibular system.

Association of cervical vestibular-evoked myogenic potential tuning property test results with MRI findings of endolymphatic hydrops in Meniere's disease.

PURPOSE: To examine the concordance between cervical vestibular-evoked myogenic potential (cVEMP) tuning property test results and MRI findings of endolymphatic hydrops (EH). METHODS: Fourteen subjects (age 24-76 years) that had been diagnosed with unilateral definite Meniere's disease (MD) (N = 8) or unilateral probable MD (N = 6) were enrolled. All of the subjects underwent cVEMP tests (using 500 Hz and 1000 Hz tone bursts), pure-tone audiometry, and gadolinium-enhanced 3 T-MRI. To examine tuning properties of cVEMP, the 500-1000 Hz amplitude ratio was calculated as the SLOPE. The results of the cVEMP tuning property test results were compared with EH-related MRI findings. RESULTS: EH positivity in both the cochlea and vestibule on MRI was observed in 7 of the 8 affected ears of definite MD and 3 of the 6 affected ears of probable MD, although it was only in one of the 14 unaffected ears. EH(+) or no response (NR) in cVEMP tuning property test was significantly associated with EH positivity on MRI, while EH(-) in the cVEMP tuning property test was significantly associated with EH-negativity on MRI (p = 0.0016 Fisher's exact test test). CONCLUSION: EH(+) or NR in the cVEMP tuning property test correspond well to EH positivity in the MRI findings. The cVEMP tuning property test is useful for screening and following up EH.

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).

MRI contribution for the detection of endolymphatic hydrops in patients with superior canal dehiscence syndrome.

PURPOSE: Patients with superior semicircular canal dehiscence syndrome, which can only be treated by surgery, present cochleo-vestibular symptoms related to a third-mobile window but also endolymphatic hydrops. Since cVEMP and oVEMP are disturbed by the presence of the dehiscence, the aim of the study is to assess the value of MRI for the diagnosis of endolymphatic hydrops in patients with superior semicircular canal dehiscence syndrome in comparison with cVEMP and oVEMP. METHODS: In this retrospective cohort study we enrolled 33 ears in 24 patients with superior semicircular dehiscence syndrome who underwent a 4-h delayed intravenous Gd-enhanced 3D-FLAIR MRI and pure tone audiometry, cVEMP and oVEMP. For each patient MRI images were evaluated by two radiologists who used a compartmental endolymphatic hydrops grading system in comparison with cVEMP and oVEMP. RESULTS: Endolymphatic hydrops was found on MRI in 9 out of 33 SCDS ears (27.3%). We found no significant correlation between the presence of endolymphatic hydrops on MRI and cVEMP and oVEMP (p = 0.36 and p = 0.7, respectively). However, there was a significant correlation between the presence of endolymphatic hydrops on MRI and the degree of sensorineural hearing loss, Air Conduction-Pure Tone Average level (p = 0.012) and Bone Conduction-Pure Tone Average level (p = 0.09), respectively. CONCLUSION: We demonstrated that EH might be observed in 27.3% of superior semicircular dehiscence syndrome ears. The role of inner ear MRI is important to detect endolymphatic hydrops, since cVEMP and oVEMP are disturbed by the presence of the dehiscence, because these patients could benefit from a medical treatment. LEVEL OF EVIDENCE: Level 3.

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.

Effect of late-onset blindness on cervical vestibular evoked myogenic potentials.

PURPOSE: Approximately 1.3 billion people worldwide have vision impairment. The aim of the present study was to investigate the influence of Late-Onset blindness on cervical vestibular evoked myogenic potentials (cVEMP) responses. Accordingly, this study was performed to investigate and compare the parameters of the cVEMP test in sighted and late-onset blind individuals. MATERIALS AND METHOD: In this cross-sectional- comparative study, cVEMP was recorded by presenting a tone burst stimulus of 500 Hz with an intensity of 95 dBnHL in 20 sighted and 20 late-onset blind individuals aged between 18 and 30 years old. RESULTS: cVEMP was observed in all the individuals (100%). The average latency of P13 and N23, amplitude, amplitude ratio, and VEMP threshold did not differ significantly between the two groups (p > 0.05). CONCLUSION: The findings of the study revealed that the formation of the neural pathway and reflex arch of cVEMP is similar between late-onset blind and sighted individuals. Thus, cVEMP can be a suitable test for assessing the vestibular function of late-onset blind people.

Constant severe imbalance following traumatic otoconial loss: a new explanation of residual dizziness.

Benign paroxysmal positional vertigo (BPPV) is the most common type of vertigo, caused by otoconia falling from the utricle into a semicircular canal (SCC). After successful repositioning maneuvers residual dizziness (RD) has been described and several reasons are used to explain RD. It can last for only a few days or weeks, but also much longer. We present a patient with a severe traumatic loss of otoconia from both maculae utriculi and a persistent imbalance more than 9 years. We think that the loss of otoconia from the utricular and probably also saccular macula induced a sudden reduction of her ability to sense gravity thus logically explaining her symptoms. We show the vestibular test results also supporting our hypothesis and we extrapolate this support to other forms of so far unexplained dizziness especially increasing imbalance with aging. We also discuss the normal c- and oVEMP indicating intact haircell function and supporting our hypothesis of isolated otoconial loss as the major cause for imbalance.

Contemporary review of the causes and differential diagnosis of sudden sensorineural hearing loss.

Objectives: This article provides an overview of the causes and differential diagnosis of sudden deafness (SD) and sudden sensorineural hearing loss (SSHL).Design: Contemporary review.Study sample: This review is based on peer-reviewed articles published in those journals listed on journal of citation reports. Through the PubMed database of the US National Library of Medicine, Scopus, and Google Scholar using the keywords of "sudden deafness", "acute hearing loss", and "sudden sensorineural hearing loss", totally 1493 papers were considered and 166 relevant papers were selected.Results: Sensorineural hearing loss of sudden onset may be classified as primary SD and secondary SSHL. Proposed aetiologies of primary SD comprised viral infection, vascular insufficiency, autoimmune disorder and stress theory, while causes of secondary SSHL include neoplasm, stroke and irradiation.Conclusion: SD/SSHL is a syndrome that comprises various entities, and results from a variety of aetiologies. An inner ear test battery in SD/SSHL patients helps determine its aetiology, and provides comprehensive information on the affected territory. Identification of the cause and differential diagnosis of the different types of SD/SSHL may provide substantial benefits such as determining the prognosis, identifying associated risk factors and preventing further hearing loss.

[Effective diagnostics for vertigo, dizziness and equilibrium disorders]. / Effektive Diagnostik bei Schwindel und Gleichgewichtsstörungen.

Vertigo, dizziness and equilibrium disorders are symptoms with a variety of causes. First, four cardinal questions (type and duration of the vertigo, triggering factors, accompanying symptoms) must be answered. After that, the search for a spontaneous nystagmus (differentiation of peripheral and central disorder using the HINTS[head impulse, nystagmus, test of skew]-test ) and, as part of a positioning examination, the search for a benign paroxysmal positional vertigo (BPPV) are necessary. If the result is negative an instrument-based receptor-specific examination is carried out. The caloric examination (low-frequency stimulus) tests the horizontal semicircular canal and the superior vestibular nerve, whereas the 3­D video head impulse test (vHIT, high-frequency stimulus) is used to analyze all three semicircular canals as well as the superior and inferior vestibular nerves. Analysis of the cervical vestibular evoked myogenic potential (cVEMP) checks the function of the sacculus and that of the ocular VEMP (oVEMP) checks the function of the utriculus. The final overall analysis usually gives a definitive diagnosis or at least provides a suspected diagnosis, which then determines the further diagnostic procedure (e.g. targeted radiological diagnostics if vestibular paroxysmia, superior canal dehiscence or a vestibular schwannoma are suspected).

Heat shock protein 70 is a key molecule to rescue imbalance caused by low-frequency noise.

A previous study showed that people living in urban areas are generally exposed to low-frequency noise (LFN) with frequencies below 100 Hz and sound levels of 60-110 dB in daily and occupational environments. Exposure to LFN has been shown to affect balance in humans and mice. However, there is no information about prevention of LFN-mediated imbalance because of a lack of information about the target region based on health risk assessment of LFN exposure. Here, we show that acute exposure to LFN at 100 Hz, 95 dB, but not at 85 dB or 90 dB, for only 1 h caused imbalance in mice. The exposed mice also had decreased cervical vestibular-evoked myogenic potential (cVEMP) with impaired activity of vestibular hair cells. Since imbalance in the exposed mice was irreversible, morphological damage in the vestibules of the exposed mice was further examined. The exposed mice had breakage of the otoconial membrane in the vestibule. LFN-mediated imbalance and breakage of the otoconial membrane in mice were rescued by overexpression of a stress-reactive molecular chaperone, heat shock protein 70 (Hsp70), which has been shown to be induced by exposure of mice to 12 h per day of LFN at 95 dB for 5 days. Taken together, the results of this study demonstrate that acute exposure to LFN at 100 Hz, 95 dB for only 1 h caused irreversible imbalance in mice with structural damage of the otoconial membrane as the target region for LFN-mediated imbalance, which can be rescued by Hsp70.

Comparing the sensitivity and specificity of cervical vestibular-evoked myogenic potentials and electrocochleography in the diagnosis of Ménière's disease.

Objective: To compare the sensitivity and specificity of objective cervical vestibular-evoked myogenic potential (cVEMP) tuning curves and electrocochleography (ECochG) for the diagnosis of Ménière's disease (MD). Design: Sensitivity and specificity were calculated from 95% normative ranges of 500 Hz cVEMP threshold and ECochG SP/AP amplitude ratios. Measures: Extra-tympanic ECochG testing to 90 dB nHL clicks and cVEMP threshold tuning curves (250-1000 Hz). Study sample: We tested 15 patients (30 ears) diagnosed with definite bilateral MD based on the clinical criteria proposed by the American Academy of Otolaryngology Head and Neck surgery, 1995 (assumed gold standard) and 20 controls. Results: 500 Hz cVEMP threshold was the most promising parameter to differentiate MD ears from controls. cVEMP and ECochG showed high specificity (83.3 and 100%, respectively) and low to moderate sensitivity (22.2 and 71.4%) for long term MD. ECochG sensitivity increased to 89% during a symptomatic period, compared to 33% for cVEMP. However, ECochG can be difficult to schedule during symptomatic periods. Sensitivity of cVEMP for the diagnosis of MD appears limited. Conclusions: ECochG has higher sensitivity than cVEMP in the diagnosis of Ménière's patients, but the ECochG SP/AP amplitude ratio measure is not perfect for the diagnosis of MD.

Objective methods to measure vestibular evoked myogenic potential response saccular tuning curves.

Objective: To detect cervical vestibular evoked myogenic potential (cVEMP) responses using objective statistical approaches and to apply this approach to estimate saccular frequency-tuning curves in volunteers and Ménière's disease (MD) patients. Design: Estimates of cVEMP threshold were carried out by 3 expert raters at 500 Hz and compared to objective threshold estimates (using Hotelling's T2 [HT2] and Fsp). Saccular tuning curves were objectively estimated. Study sample: Objective and subjective estimates of cVEMP response thresholds were compared for 13 normal hearing adults. Objective measurement of saccular tuning curves was explored in 20 healthy adults and 15 patients with MD. Results: Significant variability was seen between subjective estimates of cVEMP thresholds. Objective analysis with the HT2 test was more sensitive than 2 of 3 experts in detecting responses. The measurement time of cVEMP was considerably reduced with the HT2 test. Objective saccular tuning curves in volunteers showed strongest responses at 500 Hz. A flatter tuning curve was seen for MD patients. Conclusions: There is significant variability in subjective estimations of cVEMP thresholds. Objective analysis methods are more sensitive than subjective analysis, can detect responses rapidly and have potential to reduce variability in threshold estimates, hence they appear well suited to measure cVEMP tuning curves.