Vestibular Evoked Myogenic Potentials Research Articles

STUDY OF OTOACOUSTIC EMISSIONS AS AN ADJUVANT IN THE DIAGNOSIS OF ENDOLYMPHATIC HYDROPS

Endolymphatic hydrops (EH) results from increased endolymph volume in the inner ear, which leads to episodic vertigo, ear fullness, and sensorineural hearing loss. In these patients, Vestibular Evoked Myogenic Potential (VEMP) examination has high sensitivity and specificity for diagnosis. These patients have also been suggested to have frequency-specific changes in otoacoustic emissions (OAE). The aim of this study is to evaluate the result of the OAE examination in patients with altered VEMP and clinical history compatible with EH. The medical records and exams of 107 patients with previous diagnosis of EH were retrospectively analyzed. The results of OAE were studied for their validation in the diagnosis of patients with EH. The results showed that 98.1% of the evaluated patients presented at least one OAE frequency with no response in low or high, with a 95% confidence interval of 95.6% to 100%. When comparing the cases with normal and altered audiometry, there was a significant difference regarding the left side (p=0.041), right (p<0.001) and left (p=0.001), low (p=0.006) and high (p<0.001). Overall, a trend towards significant difference was observed (p=0.077). It is concluded that there is a significant alteration in the OAE of patients with EH, showing that such exam has the potential for diagnosis and follow-up.

Simultaneous Multifrequency (SiMFy) Stimulus: A Novel and Reliable Stimulus for Frequency Tuning of Ocular Vestibular-Evoked Myogenic Potentials.

Frequency tuning of ocular vestibular evoked myogenic potential (oVEMP) refers to the frequency of tone burst that produces the largest amplitude oVEMP. There is an ever-growing pool of published studies that found the frequency tuning of oVEMP distinctly different in Ménière's disease than the age-matched controls and benign paroxysmal positional vertigo. However, recording oVEMP in response to many frequencies makes an already lengthy vestibular test battery even more cumbersome and time-consuming. The aim of this study was to develop a novel time-saving stimulus that produces reliable results. Prospective study. The study included 25 young, healthy adults. The tone-bursts of 2000, 1500, 1000, 750, 500, and 250 Hz were generated and sequenced in this order to prepare a stimulus for simultaneous multifrequency (SiMFy) oVEMP. The response parameters of SiMFy and conventional oVEMP methods were compared. No significant difference in peak-to-peak amplitude and frequency tuning existed between conventional and SiMFy oVEMP (p > 0.05). SiMFy had better test-retest reliability and was less time-consuming than the conventional oVEMP. SiMFy is a time-saving and reliable stimulus for obtaining frequency tuning of oVEMP with no compromise on the outcomes. It can be immediately applied in most commercially available evoked potential systems with a facility for loading an external stimulus.

Simultaneous Multifrequency (SiMFy) Stimulus: A Novel and Reliable Stimulus for Frequency Tuning of Ocular Vestibular-Evoked Myogenic Potentials.

Frequency tuning of ocular vestibular evoked myogenic potential (oVEMP) refers to the frequency of tone burst that produces the largest amplitude oVEMP. There is an ever-growing pool of published studies that found the frequency tuning of oVEMP distinctly different in Ménière's disease than the age-matched controls and benign paroxysmal positional vertigo. However, recording oVEMP in response to many frequencies makes an already lengthy vestibular test battery even more cumbersome and time-consuming. The aim of this study was to develop a novel time-saving stimulus that produces reliable results. Prospective study. The study included 25 young, healthy adults. The tone-bursts of 2000, 1500, 1000, 750, 500, and 250 Hz were generated and sequenced in this order to prepare a stimulus for simultaneous multifrequency (SiMFy) oVEMP. The response parameters of SiMFy and conventional oVEMP methods were compared. No significant difference in peak-to-peak amplitude and frequency tuning existed between conventional and SiMFy oVEMP (p > 0.05). SiMFy had better test-retest reliability and was less time-consuming than the conventional oVEMP. SiMFy is a time-saving and reliable stimulus for obtaining frequency tuning of oVEMP with no compromise on the outcomes. It can be immediately applied in most commercially available evoked potential systems with a facility for loading an external stimulus.

The effect of the severity of COVID-19 on the sequelae of the audiovestibular system.

Objectives: The neurotropic and neuroinvasive properties of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been described. It remains unknown how SARS-CoV-2 affects the audiovestibular system when it causes mild or severe disease. In this study, the sequelae effect of SARS-CoV-2 on the audiovestibular systems of different patient groups was investigated using objective and subjective test batteries. Methods: In this present study, we evaluated vestibulocochlear functions of patients who previously had Coronavirus Disease-2019 (COVID-19) with pure tone audiometry, ocular vestibular-evoked myogenic potential (o-VEMP), and cervical vestibular-evoked myogenic potential (c-VEMP) tests to identify possible sequelae by comparing them with the control group. Results: We found that the amplitude of p13-n23 was lower in both groups of patients than in the control group (p < 0.001). In the results of the left ear c-VEMP, the amplitude of p13-n23 was statistically different between the outpatient, inpatient, and control groups. The amplitude of p13-n23 was lower in both groups of patients than in the control group (p < 0.001). In the evaluation of the o-VEMP in the left ear, we observed a statistically significant difference in the latency of n10 (p = 0.006) and the amplitude of n10-p15 (p < 0.001) between the groups. The n10 latency was prolonged in both groups of patients compared to the control group and there was no statistically significant difference between groups of patients. Furthermore, the amplitude of n10-p15 was lower in both groups of patients compared to the control group and there were no statistically demonstrable differences between the groups of patients. Conclusions: In conclusion, our results suggest that SARS-CoV-2 may affect the vestibulocochlear system. But we could not find a direct relationship according to the severity of the disease.

Temporal Modulation Transfer Functions of Amplitude-Modulated Cervical Vestibular-Evoked Myogenic Potentials in Young Adults.

Cervical vestibular-evoked myogenic potentials (cVEMPs) are widely used to evaluate saccular function in clinical and research applications. Typically, transient tonebursts are used to elicit cVEMPs. In this study, we used bone-conducted amplitude-modulated (AM) tones to elicit AMcVEMPs. This new approach allows the examination of phase-locked vestibular responses across a range of modulation frequencies. Currently, cVEMP temporal modulation transfer functions (TMTFs) are not well defined. The purposes of the present study were (1) to characterize the AMcVEMP TMTF in young, healthy individuals, (2) to compare AMcVEMP TMTFs across different analysis approaches, and (3) to determine the upper frequency limit of the AMcVEMP TMTF. Young adults (ages 21 to 25) with no history of vestibular lesions or middle ear pathologies participated in this study. Stimuli were amplitude-modulated tones with a carrier frequency of 500 Hz and modulation frequencies ranging from 7 to 403 Hz. Stimuli were presented at 65 dB HL via a B81 bone-oscillator. AMcVEMP waveforms consisted of transient onset responses, steady-state responses, and transient offset responses; the behavior of these different types of responses varied with modulation frequency. Differences in the TMTF shape were noted across different measures. The amplitude TMTF had a sharp peak, while signal-to-noise ratio and phase coherence TMTFs had broader shapes with plateaus across a range of modulation frequencies. Amplitude was maximal at modulation frequencies of 29 and 37 Hz. Signal-to-noise ratio maintained its peak value at modulation frequencies between 17 Hz and 127 Hz. Phase coherence and modulation gain maintained their peak values at modulation frequencies between 17 Hz and 143 Hz. AMcVEMPs reflect transient onset and offset responses, as well as a sustained response with the periodicity of an amplitude-modulation frequency. AMcVEMP TMTFs had variable shapes depending on the analysis being applied to the response; amplitude had a narrow shape while others were broader. Average upper frequency limits of the AMcVEMP TMTF were as high as approximately 300 Hz in young, healthy adults.

A Systematic Review of Vestibular Evoked Myogenic Potential in Individuals with Motion Sickness

AbstractThe otolith of vestibular system in the human body helps in maintaining the static balance. Travelling can cause defect in static balance that may lead to motion sickness. The evidence showing the relation between vestibular evoked myogenic potential (VEMP) that assesses otolith function and motion sickness is contrasting. The current systematic review is aimed to understand outcomes of published articles in reporting association between vestibular evoked myogenic in individuals with motion sickness. For this study, the database used is PubMed, Scopus, ProQuest, CINHAL, and Web of Science. The data is extracted from the final articles where VEMP is done on individuals with and without motion sickness. The total articles included are 125 out of which five articles used for the systematic review. In this study, motion sickness susceptibility questionnaire is used to assess individuals with and without motion sickness. The latency and amplitude of both cervical VEMP (cVEMP) and ocular (oVEMP) of individuals with and without motion sickness are normal. However, the review indicates a significant change in the interaural asymmetry ratio of both cVEMP and oVEMP results in individuals with motion sickness. This shows that there might be a variation in the functional asymmetry in the otoliths. From the review, it is clear that there might be otolith changes due to motion sickness that can have a smaller impact on the interaural asymmetry ratio in VEMP. These findings can be further applied for the diagnostic purpose in individuals with motion sickness.

Video Head Impulse Test in Persons with Blindness: Feasibility and Outcomes

To achieve balance, persons with blindness (PWB) use proprioceptive and vestibular cues rather than the visual system; however, PWB are equally susceptible to acquire vestibular disorders. Reliable assessments of the vestibular system in PWB are essential to determine the presence or absence of vestibular disorders. The saccular and the utricular functioning can be assessed using cervical vestibular-evoked myogenic potential and ocular vestibular-evoked myogenic potential, respectively. Evaluation of the functional integrity of the semicircular canals requires an assessment of the vestibular ocular reflex; however, this can be challenging in PWB. Video head impulse test (vHIT) assesses the vestibular ocular reflex (VOR) elicited against the natural high-frequency head movement in the planes of all six semicircular canals. This study aimed to explore the feasibility and outcomes of administering vHIT in PWB. Standard (static) groups comparison. Nineteen young PWB and 23 age-matched adults with "normal" vision (control group) were included in the study. PWB underwent vHIT once, while the control group was tested in three conditions; condition 1 was used to simulate blindness for the control group, where vHIT was done in a pitch-dark room without prior instructions; condition 2 included vHIT testing in daylight, without a fixed visual target and any instructions; and condition 3 involved vHIT in daylight in the presence of a set visual target and with standard instructions to maintain visual focus on the visual target. The VOR gain was abnormal in the PWB group for all the canals. Among the PWB, the lateral canals (mean = 0.63) had the best VOR gain, followed by the anterior canals (mean = 0.53) and the posterior canals (mean = 0.31). In the control group, the VOR gain was significantly reduced in condition 1. There was no significant difference between the VOR gain in the PWB group and the control group in condition 1 for the lateral and the anterior canals. A higher proportion of participants in the PWB group had the presence of refixation saccades. VOR is significantly reduced in PWB but not completely absent. There may be a need to develop normative data for blind individuals to decide whether or not a person with blindness has a vestibular dysfunction, specifically a VOR deficit.

Correlation between cervical vertigo and vestibular function evaluated by vestibular evoked myogenic potentials

To analyze the relationship between cervical vertigo and vestibular function evaluated by vestibular evoked myogenic potentials(VEMPs) and analyze the correlations between cervical vertigo and vestibular dysfunction, discuss the related factors of cervical vertigo and guide the clinical treatment of patients with cervical vertigo. A total of 75 patients with cervical vertigo as the main complaint in the outpatient clinic of the Second Hospital of Shanxi Medical University from August 2019 to July 2020 were set as the diseased group, and 60 patients without cervical and vestibular related diseases in the hospital were selected to set as non-diseased group. The age of diseased group was 12 to 70 years with an average of (46.40±10.91) years, including 25 males and 50 females;and the age of non-diseased group was 22 to 60 years with an average of(43.78±7.75) years, including 19 males and 51 females. VEMPs were performed in the two groups. The data of VEMPs were collected and the results were compared and analyzed. The patients with abnormal cervical myogenic vestibular evoked myogenic potential (cVEMP) were divided into light, moderate and severe groups. The correlation between VEMPs and cervical vertigo and its severity were analyzed by statistical method. (1)The severity of cervical vertigo in diseased group:33 cases of mild, 34 cases of moderate, 8 cases of severe; cVEMP examination:62 cases were positive and 13 cases were negative, including 13 cases of mild, 33 cases of moderate, 16 cases of severe. The cVEMP of non-diseased group:4 cases were positive and 56 cases were negative.(2) The level of cVEMP in diseased group was higher than that in non-diseased group (P<0.001). It can be considered that there was a correlation between cervical vertigo and vestibular function.(3)The correlation between the level of cVEMP and the level of cervical vertigo in diseased group was analyzed. The Spearman rank sum test was used, and the correlation coefficient was 0.687, which was statistically significant (P<0.05). And it can be considered that the two indicators have a high degree of correlation. It is feasible to evaluate the relationship between cervical vertigo and vestibular function by VEMPs. For patients with cervical vertigo, the higher the severity, the greater the positive rate of VEMPs, which indicates that it has a greater impact on vestibular function. The treatment of patients with cervical vertigo should be the combination of cervical rehabilitation and vestibular function.

Effectiveness of galvanic vestibular evoked myogenic potential for evaluation of Meniere’s disease

ObjectivesAlthough the cause of Meniere’s disease (MD) is not fully understood, endolymphatic hydrops is widely believed to be responsible for MD. Previous studies have used Air-Conducted Sound (ACS)-induced Vestibular Evoked Myogenic Potentials (VEMPs) to evaluate otolithic function in patients with MD. However, the use of Galvanic Vestibular Stimulation-VEMPs (GVS-VEMPs) with other vestibular tests in MD has been rare. This study aimed to explore the application of galvanic VEMPs in assessing MD. MethodsNormal individuals and patients with unilateral definite MD were included in this retrospective study. All participants underwent pure tone audiometry. Ocular and cervical VEMPs induced by GVS, and ACS were recorded. The characteristic parameters of VEMPs (n1 latency, p1 latency, amplitude, and AR) were analyzed. ResultsThe provocation rates of GVS-VEMPs did not differ between MD patients and control individuals. Compared with ACS, GVS could evoke potentials with longer latencies. MD patients presented GVS-VEMPs with lower amplitudes and ACS-cVEMP with shorter latencies and had a higher response rate in GVS-oVEMP. However, no differences or correlations were found in the characteristic parameters of GVS-VEMPs among the different stages of MD. ConclusionsGVS is as effective as ACS for inducing VEMP, and GVS-VEMP recording can detect retrolabyrinthine degeneration in MD. Further research is needed to assess the utility of GVS-VEMP in the evaluation of MD severity. Level of evidenceLevel 4.

Uneven Effects of Sleep Apnea on Semicircular Canals and Otolithic Organs.

ObjectiveThis study aimed to explore how obstructive sleep apnea (OSA) affects the function of each vestibular organ and to identify the correlations among them.MethodsA prospective study was conducted involving 32 healthy controls and 64 patients with OSA. The objective detection methods of the utricle and saccule are vestibular-evoked myogenic potentials (VEMPs). A combination of the caloric test and video head impulse test (vHIT) was used to comprehensively evaluate the objective function of semicircular canals.ResultsElevated thresholds (p < 0.001), decreased waveform amplitudes (p < 0.001), prolonged first wave latencies (p < 0.001), and shortened first interpeak latencies (p < 0.001) were observed in both ocular VEMP (oVEMP) and cervical VEMP (cVEMP). A significant difference was found in the caloric test comparison (χ2 = 4.030, p = 0.045) but not in the vHIT. The intergroup comparison of normal rates among the VEMPs, caloric test, and vHIT groups showed a significant difference (p < 0.001).ConclusionThe impairment of vestibular function in patients with OSA was uneven and biased. More attention should be given to vestibular dysfunction in the diagnosis and treatment of OSA.

Nonlinearity in bone-conducted amplitude-modulated cervical vestibular-evoked myogenic potentials: harmonic distortion products.

Otolith organs of the balance system, the saccule and utricle, encode linear acceleration. Integrity of the saccule is commonly assessed using cervical vestibular-evoked myogenic potentials (cVEMPs) arising from an inhibitory reflex along the vestibulospinal pathway. Conventional approaches to eliciting these responses use brief, transient sounds to elicit onset responses. Here we used long-duration amplitude-modulated (AM) tones to elicit cVEMPs (AMcVEMPs) and analyzed their spectral content for evidence of nonlinear processing consistent with known characteristics of vestibular hair cells. Twelve young adults (ages 21-25) with no hearing or vestibular pathologies participated in this study. AMcVEMPs were elicited by bone-conducted AM tones with a 500-Hz carrier frequency. Eighteen modulation frequencies were used between 7 and 403 Hz. All participants had robust distortion products at harmonics of the modulation frequency. Total harmonic distortion ranged from approximately 10 to 80%. AMcVEMPs contain harmonic distortion products consistent with vestibular hair cell nonlinearities, and this new approach to studying the otolith organs may provide a noninvasive, in vivo method to study nonlinearity of vestibular hair cells in humans.NEW & NOTEWORTHY The otolith balance organs of humans are assessed for basic science and clinical applications by using vestibular-evoked myogenic potentials (VEMPs). Traditionally, VEMPs are elicited with brief, transient sounds to study onset responses. We used long-duration sounds to elicit steady-state VEMPs. This allowed us to measure nonlinear distortion products, consistent with nonlinear processing in vestibular hair cells. This new approach may help to better understand links between otolith organs and balance function.

Linking Vestibular Function and Subcortical Gray Matter Volume Changes in a Longitudinal Study of Aging Adults

Emerging evidence suggests a relationship between impairments of the vestibular (inner ear balance) system and alterations in the function and the structure of the central nervous system (CNS) in older adults. However, it is unclear whether age-related vestibular loss is associated with volume loss in brain regions known to receive vestibular input. To address this gap, we investigated the association between vestibular function and the volumes of four structures that process vestibular information (the hippocampus, entorhinal cortex, thalamus, and basal ganglia) in a longitudinal study of 97 healthy, older participants from the Baltimore Longitudinal Study of Aging. Vestibular testing included cervical vestibular-evoked myogenic potentials (cVEMP) to measure saccular function, ocular VEMP (oVEMP) to measure utricular function, and video head impulse tests to measure the horizontal semicircular canal vestibulo-ocular reflex (VOR). Participants in the sample had vestibular and brain MRI data for a total of one (18.6%), two (49.5%), and three (32.0%) visits. Linear mixed-effects regression was used to model regional volume over time as a function of vestibular physiological function, correcting for age, sex, intracranial volume, and intersubject random variation in the baseline levels and rates of change of volume over time. We found that poorer saccular function, characterized by lower cVEMP amplitude, is associated with reduced bilateral volumes of the basal ganglia and thalamus at each time point, demonstrated by a 0.0714 cm3 ± 0.0344 (unadjusted p = 0.038; 95% CI: 0.00397–0.139) lower bilateral-mean volume of the basal ganglia and a 0.0440 cm3 ± 0.0221 (unadjusted p = 0.046; 95% CI: 0.000727–0.0873) lower bilateral-mean volume of the thalamus for each 1-unit lower cVEMP amplitude. We also found a relationship between a lower mean VOR gain and lower left hippocampal volume (β = 0.121, unadjusted p = 0.018, 95% CI: 0.0212–0.222). There were no significant associations between volume and oVEMP. These findings provide insight into the specific brain structures that undergo atrophy in the context of age-related loss of peripheral vestibular function.

Bedside and laboratory diagnostic testing in myasthenia

Myasthenia gravis (MG) and congenital myasthenic syndromes (CMS) are a group of disorders with a well characterised autoimmune or genetic and neurophysiological basis. We reviewed the literature from the last 20 years assessing the utility of various neurophysiological, immunological, provocative and genetic tests in MG and CMS. Diagnostic sensitivity of repetitive nerve stimulation test ranges between 14 and 94% and specificity between 73 and 100%; sensitivity of single-fibre EMG (SFEMG) test ranges between 64 and 100% and specificity between 22 and 100%; anti-acetylcholine receptor (AChR) antibody sensitivity ranges from 13 to 97% and specificity ranges from 95 to 100%. Overall, SFEMG has the highest sensitivity while positive anti-AChR antibodies have the highest specificity. Newer testing strategies that have been investigated over the last couple of decades include ocular vestibular-evoked myogenic potentials, otoacoustic emissions and disease-specific circulating miRNAs in serum for autoimmune myasthenia, as well as next-generation sequencing for genetic testing of CMS. While there has been significant progress in developing newer testing strategies for diagnosing MG and CMS over the last couple of decades, more research is needed to assess the utility of these newer tools regarding their sensitivity and specificity.

Effects of primary Sjögren's syndrome on hearing and vestibular systems.

This study aimed to evaluate primary Sjögren's syndrome patients in terms of hearing and vestibular functions. The patient group consisted of 35 individuals diagnosed with primary Sjögren's syndrome and a control group of 35 healthy individuals similar in terms of age and gender. The rate of hearing loss in the patient group was significantly higher than in the control group (p = 0.021). The N1 latency value for the ocular vestibular-evoked myogenic potentials test was significantly longer in the patient group than in the control group (p = 0.037). Additionally, the posterior semicircular canal and lateral semicircular canal vestibulo-ocular reflex gain values were significantly lower than in the control group (p = 0.022 and p < 0.001, respectively). These results indicate subclinical vestibular involvement and hearing loss in primary Sjögren's syndrome patients. Vestibular-evoked myogenic potentials and video head impulse tests can be used to detect vestibular involvement in primary Sjögren's syndrome patients.

Galvanic vestibular-evoked myogenic potentials in evaluating damaged sites of vestibular neuritis.

ObjectivesTo test the possibility of pure otolithic organ deficits and validate the histopathological evidence of retrovestibular neural impairment in vestibular neuritis (VN), the authors adopted a topographic survey combining cervical vestibular‐evoked myogenic potential (cVEMP) and ocular vestibular‐evoked myogenic potential (oVEMP) using various stimulation modes and caloric tests.MethodsForty patients with VN were enrolled in this study. All patients underwent pure tone audiometry, acoustic cVEMP, galvanic cVEMP, vibratory oVEMP, galvanic oVEMP, and caloric tests. Different combinations of vestibular tests were further compared and analyzed.ResultsAccording to vestibular test results in affected VN ears, the proportion (10%) of pure saccular dysfunction was significantly less than that (52.5%) of saccular nerve deficit. The proportion (2.5%) of pure utricular dysfunction was significantly less than that (37.5%) of utricular nerve deficit. The percentage (82.5%) of VN involving the ampullar vestibulo‐ocular reflex (VOR) pathway was significantly higher than that (40%) involving the utriculo‐ocular reflex (UOR) pathway. The superior, inferior, and total VN percentages were 37.5%, 17.5%, and 45%, respectively. The proportion of inferior VN was significantly less than that of VN involving the superior vestibular nerve.ConclusionThere were significantly fewer cases of pure otolithic organ dysfunction than vestibular nerve involvement in VN patients. The damage to the ampullar VOR pathway was more significant than that to the UOR pathway, and both pathways might be independent of each other. In addition, the incidence of isolated inferior VN was significantly less than that of VN involving the superior vestibular nerve.Level of EvidenceLevel 3.

A Portrait of Menière's Disease Using Contemporary Hearing and Balance Tests.

Menière's disease (MD) is characterized by recurrent vertigo and fluctuating aural symptoms. Diagnosis is straightforward in typical presentations, but a proportion of patients present with atypical symptoms. Our aim is to profile the array of symptoms patients may initially present with and to analyze the vestibular and audiological test results of patients with a diagnosis of MD. A retrospective study of patient files. A tertiary, neuro-otology clinic Royal Prince Alfred Hospital, Sydney, Australia. We identified 375 patients. Their history, examination, vestibular-evoked myogenic potentials (VEMP), video head-impulse test, canal-paresis on caloric testing, subjective visual horizontal (SVH), electrocochleography, ictal nystagmus, and audiometry were assessed. Atypical presenting symptoms were disequilibrium (n = 49), imbalance (n = 13), drop-attacks (n = 12), rocking vertigo (n = 2), and unexplained vomiting (n = 3), nonspontaneous vestibular symptoms in 21.6%, fluctuation of aural symptoms only (46%), and headaches (31.2%). Low velocity, interictal spontaneous-nystagmus in 13.3% and persistent positional-nystagmus in 12.5%. Nystagmus recorded ictally in 90 patients was mostly horizontal (93%) and of high velocity (48 ± 34°/s). Testing yielded abnormal caloric responses in 69.6% and abnormal video head impulse test 12.7%. Air-conducted cervical VEMPs were abnormal in 32.2% (mean asymmetry ratio [AR] 30.2 ± 46.5%) and bone-conducted ocular VEMPs abnormal in 8.8% (AR 11.2 ± 26.8%). Abnormal interictal SVH was in 30.6%, (ipsiversive n = 46 and contraversive n = 19). Mean pure-tone averages 50 dB ± 23.5 and 20 dB ± 13 for affected and unaffected ears. Menière's disease has a distinctive history, but atypical presentations with normal vestibular function and hearing are a diagnostic challenge delaying treatment initiation.

Evaluation of vestibular-evoked myogenic potential for functional integrity of the brain stem in Kennedy's disease

Objective: To investigate whether vestibular-evoked myogenic potentials(VEMPs) can be used to assess brainstem involvement in patients with Kennedy's disease (KD). Method: This was a case-control study.Twenty consecutive patients with genetically confirmed KD and 20 age-and sex-matched healthy subjects were enrolled from November 2018 to September 2020.All subjects were tested for three types of VEMPs, including cervical VEMP (c-VEMP) recorded by the sternocleidomastoid muscle (parameter:p13, n23), masseter VEMP (m-VEMP) recorded by the masseter muscle(parameter: p11), and ocular VEMP (o-VEMP) recorded by the inferior oblique muscle (parameter n10, p15).The latency of each wave, interside peak latency and interpeak latency of c-VEMP, the corrected amplitude and amplitude asymmetry ratio were recorded. Bilateral sternocleidomastoid muscle (SCMM) electromyography (EMG) was performed. The spinal cord and bulbous muscular atrophy functional rating scale (SBMAFRS) was used for assessment. Results: The mean p13 latency of c-VEMP was (15.5±1.4)ms, which was longer than that of the control group[(13.3±0.9)ms](P<0.05); the mean n23 latency was(25.5±1.4)ms, which was also longer than that of the control group[(22.5±1.0)ms] (P<0.05); the difference of bilateral p13[(2.3±0.6)ms] was significantly higher than that of the control group(P<0.05). The abnormal rates of c-, m-, o-VEMP in KD patients were 75%(15/20), 30%(6/20) and 20%(4/20), respectively. There was a significant positive correlation between c-VEMP latency and course of disease in KD patients(left: r=0.715, 0.695, right: r= 0.708, 0.715, both P<0.05). However, c-VEMP latency was negatively correlated with SBMAFRS score (left: r=-0.701, -0.694, right: r=-0.644, -0.685, both P<0.05). Abnormal rates of SCMM EMG in KD group were as follows: 15%(3/20)of patients showed spontaneous potential in resting state and 45% (9/20) of patients exhibited simple recruitment. Conclusions: The c-VEMP latency is a sensitive tool for detecting lower brainstem involvement in patients with KD, and the degree of damage increases with prolongation of disease course. The o-and m-VEMP abnormalities indicate that some KD patients develop upper brainstem damage.

Clinical correlates of different forms of endolymphatic hydrops

BackgroundThe aim of this study is to explore the different kinds of endolymphatic hydrops and the sensitivity of vestibular evoked myogenic potentials (VEMP) and electrocochleography in their diagnosis. Three groups of patients were selected according to the diagnosis, definitive MD (DMD), cochlear MD (CMD), and recurrent vestibulopathy (RV) groups. A basic audiological evaluation was carried out. It included pure tone audiometry, speech audiometry, acoustic immittancemetry testing and electrocochleography, cervical VEMP (c-VEMP), and ocular VEMP (o-VEMP).ResultsThe overall sample was 40 cases, 13 with DMD, 10 with CMD, and 17 with RV. The mean age is variable between groups (p-value < 0.001) with the highest in the DMD group (38.3 ± 7.4 years) and the lowest in the CMD group (25.2 ± 4.6 years). The male to female ratio is variable between groups of the study (p-value = 0.03) with the highest ratio 9:4 in the DMD group. There was a significant difference between groups (p < 0.001) regarding dizziness. Asymmetric response of c-VEMP was seen in nine (69.2%) of DMD cases, in 14 (82.4%) of RV cases, and only in three (30%) of CMD cases (p-value < 0.001). Low amplitude of o-VEMP was seen in 11 (84.6%) of DMD cases, 9 (90%) of CMD cases, 15 (88.2%) of RV cases, and only two (25%) of normal cases (p-value = 0.002). A significant difference was found between definitive and cochlear Meniere’s as regards o-VEMP inter-aural amplitude difference (IAD) (p-value = 0.032) only. There was a significant positive strong correlation between age and EcochG SP/AP ratio left ear, o-VEMP IAD, and o-VEMP left ear n1. In addition, there is a significant positive weak correlation between duration and EcochG SP/AP ratio left ear and c-VEMP left ear n1.ConclusionsAsymmetric response of c-VEMP can be used as a diagnostic tool to differentiate different kinds of MD: DMD, RV, and CMD.

Vestibular Test Results in Patients With Horizontal Canal Benign Paroxysmal Positional Vertigo.

IntroductionWhile the mechanism of posterior canal benign paroxysmal positional vertigo (BPPV) is widely accepted as canalolithiasis, the pathophysiology of horizontal canal BPPV remains controversial. We seek to analyze vestibular test results of patients with horizontal canal BPPV with ageotropic nystagmus (AHC) and geotropic nystagmus (GHC) in comparison to patients with posterior canal BPPV (PC) to better understand its pathophysiology.MethodsIn a retrospective chart review of adults with BPPV at a tertiary referral balance center, we reviewed the clinical characteristics and compared videonystagmography, caloric, rotary chair, subjective visual vertical (SVV)/ subjective visual horizontal (SVH), and vestibular evoked myogenic potential (VEMP) results between groups.ResultsWe included 11 AHC and seven GHC patients and randomly selected 20 PC patients as the comparison group. All groups had a high rate of migraine and low rates of diabetes and head trauma, but no difference between groups. Ipsilateral caloric weakness was more prevalent in the GHC group compared to the PC group (p=0.02). One of two AHC patients and both GHC patients who had SVV/SVH testing had abnormal findings. The only AHC patient who had ocular VEMP testing had abnormal results. Additionally, we observed a significant downbeating component to nystagmus (4 deg/sec or greater) exclusively in the AHC group (5/10 patients, p=0.001).ConclusionsPatients with AHC and GHC have unique vestibular testing results. In particular, only AHC patients showed a downbeating component to their nystagmus, which may suggest utricular dysfunction in the pathophysiology of AHC.

Impact of Cochlear Implantation on Canal and Otolith Function.

To quantify the impact of cochlear implantation (CI) on all five vestibular end-organs and on subjective ratings of post-CI dizziness. Seventy-two patients undergoing unilateral CI were recruited for the study. All participants completed pre- and post-CI three-dimensional video head-impulse tests (3D vHITs) to assess semicircular-canal (SC) function, air- and bone-conducted (AC and BC) cervical and ocular vestibular-evoked myogenic potentials (cVEMPs and oVEMPs) to assess otolith-function and the dizziness handicap inventory (DHI) to measure self-perceived disability. Nineteen percent of patients reported new or worsened dizziness postsurgery. Post-CI abnormalities (new lesions and significant deteriorations) were seen in the AC cVEMP (48%), AC oVEMP (34%), BC cVEMP (10%), and BC oVEMP (7%); and lateral (L) (17%), posterior (P) (10%), and anterior (A) (13%) SC vHITs. CI surgery was more likely to affect the AC cVEMP compared with the other tests (χ2 test, p < 0.05). Fifty percent of patients reported no dizziness pre- and postsurgery. In the implanted ear, normal pre-CI vHIT gain was preserved in lateral semicircular canal (LSC) (69%), anterior semicircular canal (ASC) (74%), and posterior semicircular canal (PSC) (67%), and normal reflex amplitudes were found in AC cVEMP (25%), AC oVEMP (20%), BC cVEMP (59%), and BC oVEMP (74%). Statistically significant decreases were observed in LSC vHIT gain, AC cVEMP amplitude, and AC oVEMP amplitude postsurgery (p < 0.05). There was a significant moderate positive correlation between change in DHI scores and the summed vestibular deficit postsurgery (r(51) = 0.38, p < 0.05). CI can impact tests that assess all five vestibular end-organs and subjective ratings of dizziness. These results support pre and post-surgical vestibular testing and assist preoperative counseling and candidate selection.