Vestibular evoked myogenic potentials in practice: Methods, pitfalls and clinical applications

Vestibular Phenotype-Genotype Correlation in a Cohort of 35 European Usher Syndrome Patients

PURPOSE

The aim of the study was to investigate genotype-phenotype correlations in Usher syndrome (USH).

METHOD

Thirty-five USH patients were included, categorized into three genetic-based groups: USH1 (n = 11), USH2 (n = 22), and USH4 (n = 2). The functional and emotional impact of dizziness and equilibrium was assessed using the Dizziness Handicap Inventory (DHI), the Hospital Anxiety and Depression Scale (HADS), and the Activities-Specific Balance Confidence (ABC) Scale. Participants underwent pure-tone threshold testing, bithermal caloric testing, rotary chair testing (RCT), video head impulse test (vHIT), ocular (oVEMP) and cervical (cVEMP) vestibular evoked myogenic potentials, and posturography. Genotype-phenotype associations were analyzed.

RESULTS

Total DHI could only distinguish USH1 (25.71 ± 21.04) from USH2 (50.13 ± 22.54, p = .024) but not between the three groups (p = .084). ABC and HADS could not also distinguish between the three USH subgroups (p = .286 and .180). Hearing loss in USH1 was significantly greater than in USH2 and USH4 (p < .001). USH1 showed greater caloric weakness than USH2 and USH4 (p < .004). RCT was not completed in USH4 but could distinguish between USH1 and USH2 (sinus 0.16 Hz, p = .033; sinus 0.32 Hz, p = .011; and sinus 0.64 Hz, p = .003). vHIT in USH1 demonstrated lower overall gain than in USH2 and USH4 (p < .001). USH1 showed higher number of absent cVEMP responses in the right and/or left ear when compared to USH2/USH4 (p < .001). USH1 showed a higher number of absent oVEMP responses in the right and/or left ear when compared to USH2 and USH4 (right ear, p < .007; left ear, p < .023). In posturography, no relevant differences were found between the three USH groups.

CONCLUSIONS

Contemporary hearing and vestibular assessment successfully differentiated between distinct USH groups. However, varying degrees of vestibular dysfunction were observed across all groups.

Novel cVEMP procedure reveals sexual dimorphism in peak to trough latency

Introduction

Sex difference in latency for cervical vestibular-evoked myogenic potential (VEMP) has been reported in Brown Norway rats. Human investigations of sex difference in VEMP latency have shown inconsistent results, although there are indicators of sexual dimorphism in vestibular function and a higher reporting rate for vestibular disorder in women than in men.

Methods

Sex effects in human VEMP were re-evaluated here using a procedure adapting clinical protocols for higher sensitivity. VEMP was compared between 24 women and 24 men using a novel procedure that (1) controlled neck tension with biofeedback and a padded head bar; (2) used body-conducted stimuli to eliminate sound exposure concerns and collect appreciably more data than is feasible with air-conducted stimuli; which in turn (3) increased statistical power because there were sufficient data for a linear mixed effects regression modelling analysis.

Results

Women had significantly shorter VEMP peak to trough latency than men. The sex difference of 2.4 ms (95% CI [-0.9, -3.9], p = 0.0020) was 21% of the mean 11.4 ms VEMP peak to trough latency measured across women and men. There was no significant sex difference in VEMP peak to trough amplitude. These findings are a reversal of several prior studies in humans, reviewed here with a simulation indicating the studies may have been underpowered.

Discussion

Findings are consistent with those in Brown Norway Rats, for which a study design featuring a custom rodent holder to control neck tension, extension of test sequences in comparison to those typically used in VEMP protocols for humans, and insertion of electrodes subcutaneously will have increased sensitivity compared to that achievable with clinical VEMP protocols for humans. Findings are interpreted as sex hormones affecting myelination or synaptic response; sexual dimorphism in neck/head size may also have contributed. The vestibular periphery and brainstem are highly conserved across vertebrates with similar findings in rat and human supporting use of VEMP as a reliable, non-invasive indicator of vestibular function. VEMP measures in humans may require higher sensitivity than is achievable using current clinical protocols in order to produce consistent results.

Long-term outcomes of pharmacotherapy in patients with persistent postural-perceptual dizziness

Introduction

Persistent postural-perceptual dizziness (PPPD) is a chronic neuro-otologic disorder characterized by vestibular symptoms such as dizziness, unsteadiness, or non-spinning vertigo. Its pathophysiology is presumed to involve sensory reweighting to visual/somatosensory sensations for maintaining spatial orientation. Serotonergic antidepressants are a major treatment option for PPPD. However, no reports describe the long-term outcomes of these therapeutic agents in patients with PPPD. Therefore, we evaluated the efficacy of antidepressants administered for up to 3 years after initiation in patients with PPPD.

Methods

Forty-three patients with PPPD (12 men and 31 women; median age at the start of treatment: 49 years) who were started on antidepressants at our department between July 2018 and February 2023 were enrolled. The Dizziness Handicap Inventory (DHI), Hospital Anxiety and Depression Scale (HADS), and Niigata PPPD Questionnaire (NPQ) were used as evaluation measures. Scores at 3 and 6 months and at 1, 1.5, 2, 2.5, and 3 years after starting the medication were compared with pre-treatment scores. Furthermore, head-tilt perception gain (HTPG), an indicator of somatosensory hypersensitivity, was measured before and after treatment.

Results

Significant improvements in all DHI, HADS, and NPQ measures were observed from 3 months onward and were maintained at all timepoints up to 3 years after treatment. Meanwhile, there was no significant improvement in HTPG after medication treatment was initiated. Patients whose DHI scores improved by ≥18 points were considered treatment responders; 27 of the 43 patients were responders at 1 year after treatment. During the initial 2 weeks of treatment, adverse events, including nausea/abdominal distension, were observed in 26 patients; however, the adverse events did not last until the subsequent observation timepoint. During the case enrollment period, antidepressants were started in 59 patients, and 43 patients included in the present study were able to continue medication (overall adherence rate: 72.9%).

Conclusions

The long-term efficacy and safety of serotonergic antidepressants were demonstrated in patients with PPPD. However, somatosensory hypersensitivity, which is sometimes observed as a clinical feature in patients with PPPD, did not improve after pharmacotherapy. Developing treatments to reduce hypersensitivity may improve treatment outcomes.

An Investigation of the Pathogenesis in Pilots With Airsickness Susceptibility Using Cervical Vestibular Evoked Myogenic Potentials

PURPOSE

The aim was to compare cervical vestibular evoked myogenic potential (cVEMP) findings between pilots who are susceptible to airsickness and those who are not and to determine whether the physiopathology arising from the sacculo-collic reflex pathway occurs during episodes of airsickness in pilots.

METHOD

The patient group included 32 male pilots susceptible to airsickness, and the control group included 30 male pilots with no airsickness susceptibility. Participants with hearing loss and neuromuscular pathology were excluded. The Graybiel scale and cVEMP test were administered to the participants. The cVEMP thresholds, wave latencies and amplitudes, and interaural amplitude asymmetry ratios (IAARs) were compared between the groups. In addition, correlation analysis was performed between IAAR and susceptibility to airsickness severity in the airsickness susceptible (AS) group.

RESULTS

The right-ear cVEMP threshold in the AS group (85.62 ± 6.05) was lower than that of the control group (91.16 ± 4.85; p < .001). In the right ears of the AS group, the P1 and N1 latencies at 100, 95, and 90 dB nHL levels were found to be shorter than those of the control group (p < .05 for all). Again, the P1N1 wave amplitudes at 100 dB nHL in the right ears of the AS group were higher than those of the control group (p = .009). The IAAR was higher in the AS group than in the control group (p < .001). There was a positive correlation between IAAR and airsickness susceptibility severity in the AS group (ρ = .742, .650, .535 at 100, 95, 90 dB nHL, respectively).

CONCLUSIONS

The susceptibility of pilots to airsickness may be related to changes in normative cVEMP latencies and amplitudes. The present study demonstrated a correlation between asymmetry in the integrity of the saccular reflex pathway and the severity of pilots' susceptibility to airsickness. A higher IAAR was observed in subjects with a greater susceptibility to airsickness, indicating a potential correlation between the two variables.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.28300112.

Effects of Noise Exposure on Video Ocular Counter Roll Measurements

PURPOSE

The purpose of this study was to evaluate the effect of noise exposure on otolith function measures of video ocular counter roll (vOCR), ocular vestibular evoked myogenic potential (oVEMP), cervical VEMP (cVEMP), and subjective visual vertical (SVV). Additionally, this study compared the vOCR results with other otolith function measures: cVEMP, oVEMP, and SVV.

METHOD

This was a cross-sectional, between-group prospective study that compared otolith function tests between noise exposure groups. Thirty-three adults between the ages of 40-60 years with no middle ear pathology, history of balance disorder, neurologic pathology, systemic diseases, or receiving ototoxic medications were included in the study. Group 1 included 17 adults (34 ears) with low-risk noise exposure, and Group 2 included 16 adults (32 ears) with high-risk noise exposure. Independent samples t tests were used to assess group mean differences for dependent variables. The independent variable was group with two levels (low risk and high risk). The dependent variables were Noise Exposure Structured Interview (NESI) score, vOCR torsion, cVEMP amplitude, oVEMP amplitude, and SVV angle. Additional analyses were completed using Pearson correlation to evaluate the relationship of vOCR to the other otolith function tests and NESI score to the otolith function tests.

RESULTS

The results indicated significantly decreased vOCR torsion, cVEMP amplitude, and oVEMP amplitude in individuals with high-risk noise exposure compared with those in the low-risk group. Significant correlations were found for NESI scores as well as vOCR and oVEMP measures.

CONCLUSIONS

This study describes the concomitant degeneration of the auditory and vestibular systems from noise exposure affecting otolith function, as measured by audiologic testing and otolith testing. vOCR appears to be sensitive to this degeneration, indicating that vOCR could be used as a vestibular screening measure for patients with noise exposure and/or suspected utricle dysfunction.

Vestibular function in children with neurodevelopmental disorders: A neglected sense?

OBJECTIVE

The study aimed to explore the vestibular function in children with neurodevelopmental disorders (NDDs).

METHODS

Twenty-eight participants with a NDD (6 girls, 22 boys; 6-13 years; 9;3 ± 2;4 years) were enrolled in this pilot study. Sixteen participants had a single NDD (Autism Spectrum Disorder: n = 7, Developmental Coordination Disorder: n = 3; Attention Deficit/Hyperactivity Disorder: n = 6), the remaining 12 had comorbid NDDs. The integrity of the peripheral vestibular system was evaluated using ocular and cervical Vestibular Evoked Myogenic Potentials (o/cVEMP), and a video Head Impulse Test (vHIT); motor competence was assessed with the Movement Assessment Battery for Children, and the KörperkoordinationsTest für Kinder. Results were compared to an age and sex-matched control group (n = 28; 9;7 ± 1;9 years).

RESULTS

The NDD group exhibited significantly higher interpeak amplitudes on both VEMP tests compared to the control group (p < 0.001). No significant differences were found between the groups on vHIT measurements (p > 0.05). Among the children with NDDs, 11 (39 %) showed atypical vestibular responses, including one child with vHIT correction saccades and three children with reduced or absent otolith responses (n = 3). Additionally, eight children showed abnormally elevated otolith amplitudes (cVEMP > 4.00 µV; oVEMP > 55.00 µV).

CONCLUSIONS

Clinicians are encouraged to recognize the overlap and consider the possibility of vestibular alterations in individuals with NDD.

SIGNIFICANCE

Incorporating vestibular assessments into routine clinical evaluations, particularly in children with NDD who exhibit delayed motor development, balance issues, hearing loss, or vestibular-related symptoms, is strongly recommended.

Evaluation of bone-conducted oVEMPs using frontal medial and mastoid stimulations

AIMS

To determine the optimal stimulation intensity for frontal stimulation with a modified slit lamp holder and to compare the reliability and symmetry of bone-conducted ocular vestibular evoked myogenic potentials (oVEMPs) using two stimulation sites: frontal medial and mastoid.

METHODS

This observational study included 33 healthy volunteers (15 women, 18 men; mean age 24.5years) at the University Hospital of Lausanne. Participants underwent otoneurological assessments, and those with normal results were included. Bone-conducted oVEMPs were recorded using a Brüel and Kjaer mini-shaker type 4810. A modified slit lamp holder was used for frontal stimulation to ensure consistent application pressure, freeing the examiner's hands. Mastoid stimulation was performed manually.

RESULTS

The best reproducibility of oVEMP recordings was observed at 70dB nHL. Frontal stimulation demonstrated lower dispersion of data and lower asymmetry ratios of latencies (up to 7%) and amplitudes (up to 50%) compared to mastoid stimulation (up to 40% for latencies). Single stimulations at both frontal and mastoid sites were sufficient to obtain reliable measurements of both utricles.

CONCLUSION

Frontal stimulation at 70dB nHL using a modified slit lamp holder is recommended for bone-conducted oVEMP recordings due to its superior reproducibility, comfort, and reliability. This study establishes a new standard for optimal stimulation intensity and supports the use of frontal stimulation in clinical practice.

Assessing otolith dysfunction in Meniere's disease: insights from multi-frequency vestibular evoked myogenic potential testing

OBJECTIVE

To investigate the impact of Meniere's Disease (MD) on balance and proprioception by utilising multi-frequency Vestibular Evoked Myogenic Potentials (VEMP) to evaluate otolith function.

DESIGN

Observational study employing the Otolith Tuning Index (OTI) to quantify vestibular function through analysis of VEMP response rates and tuning ratios.

STUDY SAMPLE

A total of 123 participants were included, comprising 94 patients diagnosed with MD and 29 healthy controls. VEMP testing was conducted at frequencies of 500 Hz, 750 Hz, and 1 kHz.

RESULTS

Among MD patients, 69% reported imbalance, with severe cases predominating in advanced stages. The non-response rate for oVEMP at 500 Hz was 73.3% on the affected side, associated with unpredictable falls. Significant correlations were observed between cVEMP non-responses and both disease severity (p = 0.012) and walking imbalance (p = 0.037). oVEMP responses were lowest at 500 Hz, improving at 1 kHz, whereas cVEMP amplitudes peaked at 500 Hz bilaterally. OTI values indicated significant otolith dysfunction on affected sides compared to contralateral sides and controls (p = 0.026, p = 0.032, p < 0.001), with dysfunction worsening with disease progression and age.

CONCLUSIONS

The Otolith Tuning Index (OTI) effectively measures otolith dysfunction in MD patients, offering valuable insights to enhance diagnostics, patient management, and treatment planning.

Teenagers and Young Adults with Cochlear Implants: A Multidisciplinary Follow-Up Study Approach and Baseline Characteristics

Background/Objectives: Early pediatric cochlear implantation positively impacts early language outcomes. The Teenager and Young Adults Cochlear Implant (TAYACI) study investigates the long-term outcomes of early implantation and factors influencing variability among cochlear implant (CI) users. This article outlines participants' background, early language outcomes, and multidisciplinary study protocol. Methods and Materials: Individuals aged 12-22 received CIs before 30 months of age, followed-up at the same hearing implant center, and adhered to a standard school curriculum were invited to participate. Out of 109 eligible CI users, 50 participated; 46 agreed to undergo clinical assessments, while four completed questionnaires only. Results: The mean age at the first CI was 15.63 months (SD = 6.0). All but one communicated with spoken language(s). Participants attended mainstream schools and had highly educated parents. Over half (56%) had received Auditory Verbal Therapy in early childhood. Earlier implantation correlated with better language understanding one year post-CI. Conclusions: Earlier implantation was associated with better early language outcomes, with parental education level and early family-centered intervention likely contributing. Future sub-studies will investigate multidisciplinary long-term effects of pediatric cochlear implantation in adolescents.

Association between vestibular evoked myogenic potentials and different dizziness status in Parkinson's disease: A controlled study

OBJECTIVE

This study compared ocular and cervical vestibular evoked myogenic potentials (oVEMP and cVEMP) among individuals with Parkinson's disease (PD) without dizziness, with nonspecific dizziness (dizziness without orthostatic hypotension), or with dizziness combined with orthostatic hypotension.

MATERIALS AND METHODS

We prospectively analyzed 30 of each of the three types of individuals who were admitted to Yongchuan Hospital of Chongqing Medical University (Chongqing, China) between June 2022 and April 2023. The three groups received oVEMP and cVEMP measurements using an electromyography-evoked potential system. For oVEMP, the N10 latency, P16 latency, and amplitude were compared between the three groups and the reference values. For cVEMP, the P13 latency, N23 latency, and amplitude were compared between the three groups and the reference values. Overall characteristics of oVEMP and cVEMP were also assessed using a previously published scoring scale originally developed for individuals with multiple sclerosis between the three groups included. The correlation between VEMP parameters (the latency and amplitude) and VEMP scores were simultaneously analyzed using Pearson's bivariate correlation analysis.

RESULTS

When compared with reference values, the oVEMP and cVEMP parameters of all three groups were found to be slightly different from the reference values. When the three groups included were compared with each other, in terms of oVEMP, the average amplitude in the left eye was significantly higher in those with nonspecific dizziness than in the other two groups. In terms of cVEMP, the average N23 latency on both the right and left sides of the neck and average amplitude on the right side of the neck were significantly higher in those with nonspecific dizziness than in the other two groups. Scores for oVEMP and cVEMP were also significantly higher for those with nonspecific dizziness than for the other two groups. There were no significant differences in oVEMP and cVEMP parameters, and scores for oVEMP and cVEMP between patients with dizziness combined with orthostatic hypotension and those without dizziness. In terms of correlation analysis, the N23 latency of left neck (r = 0.509, p < 0.001), the N23 latency of right neck (r = 0.495, p < 0.001), and the amplitude of right neck (r = 0.304, p = 0.004) correlated positively with cVEMP score.

CONCLUSIONS

Patients with PD without dizziness, with dizziness attributable to orthostatic hypotension, and with nonspecific dizziness may be all associated with vestibular dysfunction. The VEMP scores were highest in patients with nonspecific dizziness, so vestibular function is more severely affected in patients with nonspecific dizziness. The VEMP especially cVEMP may be useful for early diagnosis of nonspecific dizziness in PD.

Lesion Location and Possible Etiology of Acute Unilateral Vestibulopathy

Objective

Acute unilateral vestibulopathy (AUVP) is quite common in clinical practice, but lesion localization and etiological diagnosis of AUVP remain the current clinical challenges, and have always been the focus for researchers. The study aimed to explore the lesion site and possible etiology of AUVP.

Methods

This study is a retrospective study. Twenty-three AUVP patients who attended the neurology outpatient clinics of our hospital from January 2020 to March 2022 were included. Clinical data of patients including baseline data, cardiovascular risk factors, immunological test results and infection indicators were collected. Vestibular function tests, including video head impulse test (vHIT), caloric testing, vestibular evoked myogenic potentials (VEMPs) and post-contrast delayed 3D-FLAIR MRI, were performed.

Results

Among 32 AUVP patients included, there were 10 males and 13 females, with a male-to-female ratio of 1:1.3, and an average age of 42.13 ± 14.57 years (range 19-76 years old). Acute persistent vertigo and relapsing-remitting vertigo accounted for 39.1% (9/23) and 60.9% (14/23) of the patients, respectively. Possible etiologies included cardiovascular risk factors (n = 11), abnormal immunological indicators (n = 8), and evidence of infection (n = 3). About 57.1% (12/21) of the patients showed abnormal vHIT (including reduced gain in horizontal canal (HC) in 14.3%, anterior canal (AC) in 4.8%, both the AC and HC in 19%, both the HC and posterior canal (PC) in 14.3%, and all three canals in 9.5% of cases). Probable entire vestibular nerve damage was found in 38.1% of the patients, only 9.5% of the patients followed the innervation pattern of the entire vestibular nerve, these patients had abnormal vHIT and VEMP results, and were considered to have definite entire vestibular nerve damage. Probable superior vestibular nerve (SVN) damage was found in 47.6% of the patients, but only 4.8% (1/21) of the patients followed the innervation pattern of SVN, with reduced VOR gains for AC and HC and abnormal oVEMP results, and were considered to have definite SVN damage. 3D-FLAIR MRI revealed high signal intensity in the SVN and vestibule in 4.8% (1/21) and 19% (4/21) of the patients, respectively.

Conclusion

The majority of AUVP patients had a relapsing-remitting course and had vestibular function test results that did not follow the innervation pattern of the vestibular nerve. Post-contrast delayed 3D-FLAIR MRI revealed damage to the vestibule in some patients, suggesting that damage to the labyrinth itself in AUVP deserves clinical attention. The majority of the AUVP patients had cardiovascular risk factors and abnormal systemic immunological indicators, which might be the possible etiologies of AUVP.

Thirty years with cervical vestibular myogenic potentials: a critical review on its origin

Myogenic potentials generated by acoustic stimulation of the vestibular system have been reported since 1964. This examination became better known as cervical vestibular evoked myogenic potentials (cVEMPs) and gained increasing clinical application since the nineties. Since its discovery, the saccule has been conceived as the most likely vestibular end-organ driving these myogenic potentials of the neck. As findings from both animal and human studies for a long time uniformly provided evidence supporting this theory, cVEMP assessment has become synonymous with evaluation of saccular and inferior vestibular nerve function. This review of the basic evidence supporting this conclusion, questions if cVEMP may be considered as being predominantly or even exclusively driven by the activation of any single vestibular end-organ. We conclude that the results of this review show that contributions from the crista ampullaris of all three ipsilateral semicircular canals, as well as the ipsilateral utricle cannot be ruled out in clinically conducted cVEMP assessments.

The application value of dynamic electroencephalography combined with brainstem auditory evoked potential in evaluating the degree of vascular stenosis and prognosis in patients with ischemic stroke: A retrospective analysis

The aim was to explore the application value of dynamic electroencephalography (EEG) combined with brainstem auditory evoked potential (BAEP) in evaluating the degree of vascular stenosis and prognosis in patients with ischemic stroke (IS). This was a retrospective study using clinical data of patients with IS admitted to the First Affiliated Hospital of Chongqing Medical and Pharmaceutical College from March 2020 to March 2022. The degree of vascular stenosis and prognosis of patients were analyzed. In addition, the correlation between EEG, BAEP examination and the degree of vascular stenosis was studied. A total of 105 patients met the inclusion and exclusion criteria were included in this study. Among them, 43 cases were mild stenosis, 42 cases were moderate stenosis, and 20 cases were severe stenosis; 32 cases had poor prognosis and 73 cases had good prognosis. The quantitative electroencephalogram index (delta + theta)/(alpha + beta) ratio (DTABR), peak latency (PL) of waves I and V, and interval PL (IPL) of waves III to V and I to V in patients with moderate stenosis or severe stenosis were significantly higher than those in patients with mild stenosis (P < .05). Moreover, the above indicators were significantly higher in patients with severe stenosis than in patients with moderate stenosis (P < .05). According to Spearman test, the patients' DTABR, PL of wave I and wave V, and IPL of wave III to V and wave I to V were positively correlated with the degree of vascular stenosis, respectively (P < .05). The DTABR, wave I, wave V, wave III to V, and wave I to V of patients with poor prognosis were higher than those with good prognosis (P < .05). The DTABR, PL of waves I and V, and IPL of waves III to V and I to V in patients with poor prognosis were significantly higher than those in patients with good prognosis (P < .05). EEG combined with BAEP has high value in assessing the degree of vascular stenosis and prognosis in patients with IS, which provides a reference basis for clinical development or adjustment of subsequent intervention plans.

Navigating trends in research related to vestibular function tests through scientometrics

PURPOSE

Research on vestibular function tests has advanced significantly over the past century. This study aims to evaluate research productivity, identify top contributors, and assess global collaboration to provide a comprehensive overview of trends and advancements in the field.

METHOD

A scientometric analysis was conducted using publications from the Scopus database, retrieved on January 5, 2024. The search focused on vestibular function tests, including articles, reviews, and conference papers published between 1911 and 2023. Descriptive statistics were calculated in Microsoft Excel, while publication trends were analyzed through annual growth rate (AGR), relative growth rate (RGR), and doubling time (DT). VOSviewer software was used to visualize collaboration networks, and keyword analysis refined thematic trends.

RESULTS

From 34,134 initial publications, 26,267 were analyzed after applying filters. The majority (82.89%) were in English. Publication output has shown continuous growth, with key milestones in 1969 and 2017 when annual publications exceeded 100 and 1,000, respectively. The RGR, AGR, and DT showed increased publication activity after 1969. The United States consistently led in publication output, with significant global collaboration in recent years. A substantial increase in number of keywords and their dense connections over the years reflects richer and more holistic research in the field as time progresses.

CONCLUSION

The study demonstrates the growing importance of vestibular function research, driven by global collaboration and technological advancements. While findings guide future research and policy, further work is needed to enhance the generalizability of insights across diverse populations. Continued investment in research is essential for developing innovative diagnostics and treatments to improve patient outcomes.

Cervical Vestibular-evoked Myogenic Potential in Healthy Adults: A Cross-sectional Study Investigating the Impact of Various Stimuli and Recording Conditions

Background

Cervical vestibular-evoked myogenic potentials (c-VEMPs) is a noninvasive procedure that captures the electrical activity of sternocleidomastoid (SCM) muscles in response to auditory stimuli. The clinical value of VEMP, however, is affected by the use of appropriate stimuli and correct testing techniques. This study investigates the effects of different stimuli and recording conditions on c-VEMP recordings.

Materials and Methods

Sixty healthy participants, aged 18-60 years, underwent c-VEMP recordings. Air-conducted sound stimuli (tone bursts and clicks) in sitting, supine neck torsion, and supine head lift and neck torsion positions along with the variation in the active electrode positions were employed to obtain the c-VEMP records. The c-VEMP parameters were compared by paired t-test, Wilcoxon signed-rank test and one-way ANOVA. P < 0.05 was considered statistically significant.

Results

Tone burst and click-evoked c-VEMP varied with statistically significant differences in terms of amplitudes, corrected amplitudes, and thresholds (P = 0.0000). Tone burst stimuli produced larger amplitudes and lower thresholds in both ears. No significant difference was found in c-VEMP parameters tested for differences in active electrode placement except for threshold asymmetry (P = 0.0123) (Wilcoxon signed-rank test). c-VEMP recordings in the sitting position produced significantly larger corrected amplitudes compared to the supine head lift and neck torsion positions, for both sides (one-way ANOVA).

Conclusion

The results of the current study revealed a greater response rates and larger amplitudes for tone burst-evoked c-VEMP responses as compared to those with click stimuli. A seated, head-turned position with the active electrode placed in the middle of the SCM muscle yielded larger tone burst-evoked c-VEMP responses. The variation in the VEMP data obtained owing to different stimuli and recording conditions should be considered when evaluating patients in clinical practice to optimize the clinical applicability of the VEMP examination.

The comparison between intratympanic gentamicin prehabilitation and postoperative virtual reality exposure to standard vestibular training in patients with vestibular schwannoma

OBJECTIVE

Resection of the vestibular schwannoma causes acute peripheral vestibular loss. The process of central compensation starts immediately afterward. The rehabilitation goal is to support this process and restore the quality of life.

MATERIALS AND METHODS

In this prospective single-center study, 67 consecutive patients underwent vestibular schwannoma resection (40 females, mean age 52 ± 12 years). The patients were divided into three groups: the prehabilitation with intratympanic gentamicin group, the virtual reality group (optokinetic stimulation via virtual reality goggles in the first ten days after the surgery), and the control group. All patients were examined with objective methods and completed questionnaires before the prehabilitation, before the surgery, at the hospital discharge, and after three months.

RESULTS

Intratympanic gentamicin prehabilitation leads ipsilaterally to a significant aVOR reduction in all semicircular canals (p < 0.050), the increase of the unilateral weakness in air calorics (p = 0.026), and loss of cVEMPs responses (p = 0.017). Prehabilitation and postoperative exposure to virtual reality scenes improved the patient's perception of vertigo problems according to Dizziness Handicap Inventory (p = 0.039 and p = 0.076, respectively). These findings conform with the optokinetic testing results, which showed higher slow phase velocities at higher speeds (40 deg/s) in both targeted groups compared to the control group.

CONCLUSION

Preoperative intratympanic gentamicin positively affects peripheral vestibular function, influencing balance perception after VS resection. In long-term follow-up, prehabilitation and postoperative exposure to virtual reality improve patients' quality of life in the field of vertigo problems.

A Study on Masking Cervical Vestibular Evoked Myogenic Potentials Elicited by Vertical-Axis Vibrations through Speech Noises or Random Interstimulus-Interval Tone-Bursts

OBJECTIVE

Vestibular evoked myogenic potential (VEMP) can be elicited using bone-conducted vibration (BCV) and air-conducted sound, with BCV VEMP typically associated with bilateral vestibular pathways. We employed a new acoustic masking method to obscure BCV VEMP, aiming to explore the feasibility of unilateral BCV VEMP testing.

MATERIALS AND METHODS

Twenty healthy adults (20-37 years old; 10 males and 10 females) participated in the study. Vertical-axis vibrations (VAVs) of 500-Hz short-tone bursts (STB500) and 750-Hz short-tone bursts (STB750) were used to induce cervical VEMP. These stimuli were delivered through a Mini-Shaker placed at the vertex under three conditions: without acoustic masking (no masking [NOM]), with 100 decibels sound pressure level (dB SPL) speech noise masking (SNM), and with random interstimulus-interval tone bursts (rISITB), applied binaurally during VEMP testing.

RESULTS

The response rates for STB500 were less affected by SNM or rISITB (92.5% for NOM, 85.0% for SNM, and 75.0% for rISITB), whereas the response rates for STB750 were significantly reduced from 90.0% (NOM) to 17.5% (SNM) and 45.0% (rISITB) (p < 0.05, Fisher's exact test). The response amplitude and p13 latency of STB750 also differed significantly from those of STB500 (p < 0.05, two-way repeated measures analysis of variance). The VAVs of STB750 elicited a >90% response rate for cervical VEMP but showed an 80% decrease in response rate under SNM.

CONCLUSION

SNM proved more effective than rISITB in masking the VEMP response evoked by BCVs. This approach offers the potential for conducting VEMP tests on individual ears or targeting specific vestibular organs using BCV VEMP.

Assessment of the Inter-Frequency Amplitude Ratio (1000/500 Hz) in cVEMP and oVEMP for the Diagnosis of Ménière's Disease

Objectives: to retrospectively evaluate the clinical relevance of the 1000/500 Hz inter-frequency amplitude ratio (IFAR) in cervical and ocular vestibular evoked myogenic potentials (cVEMPs and oVEMPs) in patients with unilateral definite Ménière's disease (MD) to identify the pathological ear. Method: cVEMPs and oVEMPs results obtained at 500 Hz and 1000 Hz were retrospectively analyzed in 28 patients with unilateral definite MD. 1000/500 Hz IFAR were calculated and compared for each ear. Spearman correlation tests between patient age and 1000/500 Hz IFAR were also performed. Results: No significant difference was observed between the 1000/500 Hz IFAR calculated in both pathological and healthy ears when the cVEMPs were performed (p = 0.74; Wilcoxon signed-rank test). 1000/500 Hz IFAR results obtained in healthy and pathological ears were also not different for oVEMPs (p = 0.73; Wilcoxon signed-rank test). Analysis of modified 1000/500 Hz IFARs for healthy and pathological ears showed no difference in both cVEMPs and oVEMPs (p = 0.44; p = 0.95, respectively; Wilcoxon signed-rank test). There was a significant positive correlation between IFARs, modified IFARs, and patient age for cVEMPs (p = 0.017; p = 0.012, respectively, Spearman's correlation test). A significant positive correlation was also found between modified IFARs and the subject age in oVEMPs (p = 0.019, Spearman's correlation test). Conclusions: We did not observe any significant increase of 1000/500 Hz IFARs and 1000/500 Hz modified IFARs in ears affected by definite MD compared to healthy ears. Moreover, our research suggests that the age of the participants may influence IFAR results, which may lead to misdiagnosis in the elderly. It is, therefore, essential to conduct further prospective studies in larger cohorts, stratifying results by participant age, to better understand the role of 1000/500 Hz IFAR values in the diagnosis of MD.

Evidence of Peripheral Vestibular Impairment Among Adults With Chronic Moderate-Severe Traumatic Brain Injury

PURPOSE

Traumatic brain injury (TBI) is a leading cause of death and disability among adults in the United States. There is evidence to suggest the peripheral vestibular system is vulnerable to damage in individuals with TBI. However, there are limited prospective studies that describe the type and frequency of vestibular impairment in individuals with chronic moderate-severe TBI (> 6 months postinjury).

METHOD

Cervical and ocular vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) were used to assess the function of otolith organ and horizontal semicircular canal (hSCC) pathways in adults with chronic moderate-severe TBI and in noninjured comparison (NC) participants. Self-report questionnaires were administered to participants with TBI to determine prevalence of vestibular symptoms and quality of life associated with those symptoms.

RESULTS

Chronic moderate-severe TBI was associated with a greater degree of impairment in otolith organ, rather than hSCC, pathways. About 63% of participants with TBI had abnormal VEMP responses, compared to only ~10% with abnormal vHIT responses. The NC group had significantly less abnormal VEMP responses (~7%), while none of the NC participants had abnormal vHIT responses. As many as 80% of participants with TBI reported vestibular symptoms, and up to 36% reported that these symptoms negatively affected their quality of life.

CONCLUSIONS

Adults with TBI reported vestibular symptoms and decreased quality of life related to those symptoms and had objective evidence of peripheral vestibular impairment. Vestibular testing for adults with chronic TBI who report persistent dizziness and imbalance may serve as a guide for treatment and rehabilitation in these individuals.

Bone conducted cervical vestibular evoked myogenic potentials: comparison of tone burst stimulus vs chirp stimulus

PURPOSE

Vestibular evoked myogenic potential (VEMP) is a test used to evaluate the function of otolith organs. In healthy individuals, air-conducted (AC) responses are obtained, whereas, in conductive hearing loss, the inability to transmit the signal well enough with AC stimuli has led to the need for bone-conducted (BC) stimuli. This study aimed to compare 500 Hz Chirp and Tone Burst stimuli in terms of latency and amplitude in BC cVEMP.

METHODS

This prospective observational case control study included 35 healthy participants (70 ears) between the age of 20-50. Participants underwent VEMP testing with BC 500 Hz Tone Burst stimulus and 500 Hz narrow band Chirp stimulus without changing the position of the bone conducted vibrator. The intensity of the stimuli was 50 dB nHL.

RESULTS

Response rate of 500 Hz TB Stimulus was 51.4% and 95.7% in Chirp stimulus. It was observed that significantly more responses were obtained with Chirp stimulus than TB stimulus (p < 0.001). In terms of p1 latency, n1 latency, both latencies were significantly shorter in Chirp stimulus (p < 0.001). p1n1 amplitude was found significantly larger in Chirp stimulus (p < 0.001).

CONCLUSION

Compared to 500 Hz TB stimulus, 500 Hz Chirp stimulus results in a higher response rate, larger p1n1 amplitude, and shorter p1 and n1 latency. A higher response rate may provide a more accurate assessment of otolith organs, reducing false negatives due to signal transmission in patients.

Cavernous Hemangioma With Right Vestibulopathy: A Case Report Illustrating Multidisciplinary Clinical Decision-Making in Vestibular Diagnostics

This paper describes a case study of a 56-year-old male patient with a small cavernous hemangioma and concurrent peripheral vestibular symptoms, initially thought to warrant neurosurgical intervention. A structured, multidisciplinary approach involving audiology, ear, nose and throat, and physiotherapy revealed that peripheral vestibular dysfunction, rather than the central lesion, was the primary cause of symptoms. The report illustrates the diagnostic utility of video head impulse testing (vHIT), caloric testing, and vestibular evoked myogenic potentials (VEMPs) in differentiating central and peripheral vestibular dysfunction, leading to a nonsurgical treatment plan. The case underscores the importance of multidisciplinary collaboration in preventing unnecessary interventions and highlights an effective clinical decision-making framework for similar cases.

Effect of Cochlear Implantation on Air Conduction and Bone Conduction Elicited Vestibular Evoked Myogenic Potentials-A Scoping Review

Background/Objectives: Cochlear implantation (CI) is an effective intervention for individuals with severe to profound hearing loss; however, it may impact vestibular function due to its proximity to related anatomical structures. Vestibular evoked myogenic potentials (VEMPs) assess the function of the saccule and utricle, critical components of the vestibular system. This review examines CI's impact on air conduction (AC) and bone conduction (BC) VEMP responses. Methods: A scoping review was conducted following PRISMA guidelines, using databases such as Medline, Embase, Cochrane Library, Scopus, and ProQuest Dissertations. Studies reporting on AC and/or BC-VEMP in CI recipients were included. Data extraction focused on VEMP response rates, amplitudes, and latencies pre- and post-CI. Risk of bias/quality assessment was performed using the Newcastle-Ottawa Scale. Results: Out of 961 studies identified, 4 met the inclusion criteria, encompassing a total of 245 CI-implanted ears. Results indicated that AC-VEMP responses were often reduced or absent post-CI, reflecting the influence of surgical changes in the middle ear mechanics rather than otolith dysfunction. In contrast, BC-VEMP responses were more consistently preserved, suggesting that BC stimuli bypass the middle ear and more accurately delineate otolith function. Variations in VEMP outcomes were noted depending on the surgical approach and individual patient factors. Conclusions: CI impacts vestibular function as measured by VEMP, with AC-VEMP showing greater susceptibility to postoperative changes compared to BC-VEMP. The presence of preserved BC-VEMP alongside absent AC-VEMP underscores the need to differentiate between these measures in assessing vestibular function.

Infant Cervical Vestibular Evoked Myogenic Potentials: A Scoping Review

OBJECTIVES

Children diagnosed with hearing loss typically demonstrate increased rates of vestibular loss as compared with their peers, with hearing within normal limits. Decreased vestibular function is linked with delays in gross motor development, acquisition of gross motor skills, and academic challenges. Timely development of sitting and walking gross motor skills aids in the progress of environmental exploratory activities, which have been tied to cognitive, language, and vocabulary development. Considering the time-sensitive development of gross motor skills and cognitive, language, and vocabulary development, identifying vestibular loss in infancy can support early intervention. This scoping review analyzes stimulus, recording, and participant factors relevant to assessing cervical vestibular evoked myogenic potentials (cVEMPs) in the infant population.

DESIGN

The scoping literature review was conducted on literature published between 2000 and 2023, focusing on articles assessing cVEMPs in infants. Two authors independently followed Preferred Reporting Items for Systematic and Meta-Analysis guidelines for title and abstract screening, full-text review, data extraction, and quality assessments. Sixteen articles meeting the inclusion criteria were included in the analysis.

RESULTS

The existing literature lacks consensus regarding stimulus and recording parameters for measuring infant cVEMPs. In addition, the review reveals a decrease in cVEMP response occurrence rates with the severity of hearing loss, especially in cases of severe to profound hearing loss, compared with mild to moderate sensorineural hearing loss in infants.

CONCLUSIONS

This scoping review demonstrates the increasing use of cVEMP as a reliable tool for objectively assessing infant vestibular function. The lack of consensus in stimulus and recording parameters emphasizes the need for systematic research to establish an evidence-based protocol for cVEMP measurements in infants. Such a protocol will ensure the reliable measurement of cVEMPs in infants and enhance the effectiveness of cVEMP as part of the infant vestibular test battery. In addition, there is a necessity for a comprehensive large-scale study to evaluate the practicality and feasibility of implementing vestibular screening protocols for infants diagnosed with sensorineural hearing loss in the United States.

Vestibular function and balance performance in children with sensorineural hearing loss

OBJECTIVE

Balance difficulties are common in children with sensorineural hearing loss (SNHL). For some of these children, concomitant vestibular deficits may impact postural control. This study aimed to explore vestibular function, functional balance and postural control, and the relationship between these measures in children with SNHL.

DESIGN

Cross-sectional study quantifying peripheral vestibular function (vestibular evoked myogenic potentials [VEMP], video head impulse test), functional balance (Bruininks-Oseretsky Test of Motor Proficiency [BOT]) and postural control (static posturography with modified sensory inputs). The relationship between the degree of vestibular impairment, functional balance and postural control was explored.

STUDY SAMPLE

Eleven with SNHL, and 11 with normal sound detection (NSD) between 5 and 12 years of age.

RESULTS

Children with SNHL had varying degrees of vestibular dysfunction and differences in overall balance performance. Across all children, greater degrees of vestibular impairment were associated with significantly poorer functional balance and postural control performance for complex standing conditions (BOT percentile rank p = 0.001; compliant surface eyes open [EO]: p = 0.027; compliant surface eyes closed: p = 0.048).

CONCLUSIONS

Vestibular dysfunction in children with SNHL was variable. Vestibular impairment predicted poorer functional balance performance and postural control abilities, including differences in postural sway patterns.

Test-Retest Reliability of Tone Burst-Induced 500 Hz Air-Conduction Masseter Vestibular Evoked Myogenic Potential in Healthy Individuals

BACKGROUND AND OBJECTIVES

Masseter vestibular evoked myogenic potential (mVEMP) is a newly developed tool which is used to assess the vestibulo-trigeminal neural and saccular functioning pathways. Recently, this test was added to a full test battery for evaluating the brainstem of people with neurological disorders and other vestibular diseases. For any test to qualify as a standard test, the test must have high reliability across all testing windows. Hence, the present study focused on validating the reliability of mVEMP in a large population.

SUBJECTS AND METHODS

The study included 50 healthy participants with normal hearing. All the participants were tested using mVEMP and underwent retest within a month after the initial test. All parameters (latencies, peak-to-peak amplitude, asymmetric ratio) were observed for both sessions. To determine the statistically significant differences between and across the sessions, non-parametric tests such as Mann-Whitney U and Wilcoxon signed-rank tests were used.

RESULTS

The test-retest reliability of all parameters were observed. The reliability was fair-to-good for P11 and N21 latencies. The other parameters showed less significance. There were no significant differences in sex and ear comparisons between and across the sessions.

CONCLUSIONS

Our study demonstrated that the mVEMP is a reliable test which can be used to assess peripheral vestibular system dysfunction and neurological conditions.

Vestibular Function and Postural Control in Children with Autism Spectrum Disorder

Background: Postural control deficits have been documented in children with autism spectrum disorder (ASD), yet vestibular system contributions to postural control have not been widely considered. The purpose of this study is to explore the relationship between functional balance, postural sway, and vestibular function in children with ASD. Methods: Ten children with a confirmed diagnosis of ASD according to DSM-V guidelines along with ten children with no known neurodevelopmental or motor delays participated in the study. Bruininks-Oseretsky Test of Motor Proficiency and the Paediatric Balance Scale measured functional balance ability, and postural sway was measured using static posturography with modified sensory inputs. Peripheral vestibular function was measured using cervical vestibular evoked myogenic potentials and video head impulse testing. Correlations between measures were performed. Results: When visual cues were removed, children with ASD demonstrated larger path velocities indicative of reduced postural control, and different patterns of postural sway. Functional balance was correlated with path velocities for conditions where sensory information was modified. No differences in peripheral vestibular function were noted between groups, and functional balance was not correlated with vestibular function. Conclusions: Findings suggest that while peripheral vestibular function is similar between groups, postural control differences in children with ASD remain, particularly for conditions where sensory information is modified. Furthermore, demonstrated patterns of postural sway suggest sensory system integration is less developed in children with ASD. These findings highlight the importance of utilising a range of clinical tools to quantify balance ability and consideration of postural control measures to inform intervention.

Otolith function in Usher type II syndrome

BACKGROUND

Usher's syndrome type II (USH2) is a rare genetic disorder encompassing hearing loss, vision impairment, and apparent intact vestibular function. Recent research suggests a potential involvement of the otolith vestibular receptors in USH2.

AIMS/OBJECTIVES

Evaluate otolith dynamic function in USH2.

MATERIAL AND METHODS

Twenty-two USH2 (median age 53.9 ± 2.99) and age-matched controls underwent a complete battery vestibular testing including air conducted cervical and ocular vestibular evoked myogenic potentials (c-VEMPs and o-VEMPs). Vestibular function tests were correlated with Activities Balance Scale (ABC) and Dizziness Handicap Inventory (DHI) scores.

RESULTS

Fourteen USH2 reported previous vertigo (vs none control). Among 88 ears, c-VEMPs were absent in 15 USH2 cases and 4 controls (p = 0.034), while o-VEMPs were absent in 22 USH2 cases and 12 controls (p = 0.129). There were significant differences between USH2 vs controls in right ear o-VEMP N1 latencies (median 11.60/10.40, p < 0.010), N1-P1 amplitudes (median 5.15/10.10, p < 0.003) and in o-VEMP N1-P1 asymmetry ratio (median 24.78/40.50, p < 0.014). USH2 showed a strong correlation between o-VEMP amplitude and DHI score (p = 0.003, ρ = 0.769). No association was found between vertigo and VEMPs subgroups.

CONCLUSIONS AND SIGNIFICANCE

Our findings suggest the presence of otolith dysfunction in USH2, which is independent from subjectively reported dizziness. Incorporating vestibular testing into USH2 evaluation and monitoring could enhance characterization of this multisensory disease.

A Clinical Framework for Video Head Impulse Testing and Vestibular Evoked Myogenic Potential Assessments in Primary School-Aged Children

OBJECTIVES

This study aimed to offer normative data and age trends of an age-appropriate vestibular test protocol in a large group (n = 140) of school-aged children (6 to 13 years old) as well as to provide a practical and clinical framework for accurate performance and interpretation of vestibular test results in this specific age group.

DESIGN

The typically developing participants (mean age of 9.51 ± 2.04 years) were recruited to provide a representative group of 20 children for each of the seven age groups that were composed of children aged from 6 to 13 years in 1-year intervals. Each age group consisted of 10 boys and 10 girls. The protocol comprises the video head impulse test, and cervical and ocular vestibular evoked myogenic potential assessments to provide a child-friendly, noninvasive, short, and portable test battery, which is equally applicable in the hospital and office-practice, and which provides information on the integrity of all five parts of the peripheral vestibular system.

RESULTS

The study demonstrates that all included tests and methods, with an overall test duration of 25 min 12 sec ± 5 min 10 sec, were feasible to perform in primary school-aged children, taking into account some practical adaptations. Concerning the video head impulse test, no clinically relevant sex and age effects were noted. However, t tests revealed significant differences for the mean gain of the horizontal (right > left; t [139] = 14.563; p < 0.001) and posterior semicircular canals (left > right; t [139] = -4.823; p < 0.001) between both sides. For the cVEMP assessment, no laterality differences were observed for any of the parameters, but a significantly shorter N1 latencies in the youngest age categories (<8 years), compared with the oldest groups were observed [ F (6,118) = 8.336; p < 0.001; partial ƞ ² = 0.298]. For all oVEMP parameters, no laterality, sex, or age differences were seen. On the basis of the presented normative data, cutoff criteria were proposed with accompanying clinical recommendations to perform vestibular function testing in this target population.

CONCLUSIONS

This is the first study in a large group of school-aged children offering normative data and age trends of an age-appropriate vestibular test protocol that evaluates the integrity of all parts of the peripheral vestibular organ. The reported normative values and clinical cutoff values will enable appropriate and age-specific interpretation of clinical and scientific results. Moreover, in combination with extensive history taking, and additional vestibular testing (e.g., rotatory chair test, caloric testing) when needed, the results of this study may support clinicians in the diagnosis of side-specific and location-specific vestibular deficits, which is required for accurate counseling and referral for further follow-up and/or intervention.

Clinical features of persistent postural-perceptual dizziness coexisting with Meniere's disease in comparison with Meniere's disease alone

Background

Persistent postural-perceptual dizziness (PPPD) is a chronic vestibular syndrome often triggered by acute or episodic vestibular syndromes, such as Meniere's disease (MD). According to the diagnostic criteria, PPPD may coexist with other structural diseases, and the evidence of another active illness does not necessarily exclude PPPD diagnosis. However, persistent symptoms, even those meeting the PPPD criteria even long after Meniere's attack, are often overlooked as potential PPPD precipitated by MD. Some clinicians overlook PPPD in such patients, treating them solely for MD once diagnosed. Since a treatment strategy for PPPD is completely different from that for MD, this may result in the deprivation of adequate treatments.

Objectives

To emphasize the importance of diagnosing PPPD coexisting with MD including not treating such patients solely for MD, and to compare the clinical features of PPPD and MD.

Methods

Vestibular function tests, including canal paresis (CP)%, c- and o-vestibular myogenic potentials, vestibulo-ocular reflex-direction preponderance, and posturography and clinical symptom scales, including the Dizziness Handicap Inventory, Niigata PPPD Questionnaire, and Hospital Anxiety and Depression Scale, were compared between 105 PPPD patients with MD or other precipitants and 130 patients with MD alone. The clinical symptom scales were further compared between 23 patients with PPPD coexisting with MD and those with MD alone.

Results

The CP% was significantly higher in patients with MD than in those with PPPD. However, the total and subscores of all three clinical symptom scales were higher in patients with PPPD than in those with MD. The total score on all clinical symptom scales was higher in patients with PPPD coexisting with MD than in those with MD alone.

Conclusion

Persistent postural-perceptual dizziness development from a precipitating MD may be associated with more severe clinical symptoms. Thus, clinical symptom scales may be useful for detecting PPPD in patients with Meniere's disease.

Myogenic artifacts masquerade as neuroplasticity in the auditory frequency-following response

The frequency-following response (FFR) is an evoked potential that provides a neural index of complex sound encoding in the brain. FFRs have been widely used to characterize speech and music processing, experience-dependent neuroplasticity (e.g., learning and musicianship), and biomarkers for hearing and language-based disorders that distort receptive communication abilities. It is widely assumed that FFRs stem from a mixture of phase-locked neurogenic activity from the brainstem and cortical structures along the hearing neuraxis. In this study, we challenge this prevailing view by demonstrating that upwards of ~50% of the FFR can originate from an unexpected myogenic source: contamination from the postauricular muscle (PAM) vestigial startle reflex. We measured PAM, transient auditory brainstem responses (ABRs), and sustained frequency-following response (FFR) potentials reflecting myogenic (PAM) and neurogenic (ABR/FFR) responses in young, normal-hearing listeners with varying degrees of musical training. We first establish that PAM artifact is present in all ears, varies with electrode proximity to the muscle, and can be experimentally manipulated by directing listeners' eye gaze toward the ear of sound stimulation. We then show this muscular noise easily confounds auditory FFRs, spuriously amplifying responses 3-4-fold with tandem PAM contraction and even explaining putative FFR enhancements observed in highly skilled musicians. Our findings expose a new and unrecognized myogenic source to the FFR that drives its large inter-subject variability and cast doubt on whether changes in the response typically attributed to neuroplasticity/pathology are solely of brain origin.

Vestibular hair cells are more prone to damage by excessive acceleration insult in the mouse with KCNQ4 dysfunction

KCNQ4 is a voltage-gated K+ channel was reported to distribute over the basolateral surface of type 1 vestibular hair cell and/or inner surface of calyx and heminode of the vestibular nerve connected to the type 1 vestibular hair cells of the inner ear. However, the precise localization of KCNQ4 is still controversial and little is known about the vestibular phenotypes caused by KCNQ4 dysfunction or the specific role of KCNQ4 in the vestibular organs. To investigate the role of KCNQ4 in the vestibular organ, 6-g hypergravity stimulation for 24 h, which represents excessive mechanical stimulation of the sensory epithelium, was applied to p.W277S Kcnq4 transgenic mice. KCNQ4 was detected on the inner surface of calyx of the vestibular afferent in transmission electron microscope images with immunogold labelling. Vestibular function decrease was more severe in the Kcnq4p.W277S/p.W277S mice than in the Kcnq4+/+ and Kcnq4+/p.W277S mice after the stimulation. The vestibular function loss was resulted from the loss of type 1 vestibular hair cells, which was possibly caused by increased depolarization duration. Retigabine, a KCNQ activator, prevented hypergravity-induced vestibular dysfunction and hair cell loss. Patients with KCNQ4 mutations also showed abnormal clinical vestibular function tests. These findings suggest that KCNQ4 plays an essential role in calyx and afferent of type 1 vestibular hair cell preserving vestibular function against excessive mechanical stimulation.

Electrode Montage for Bilateral Cervical Vestibular-Evoked Myogenic Potential Testing

BACKGROUND

 Cervical vestibular-evoked myogenic potentials (cVEMPs) are predominantly ipsilateral, myogenic responses originating from saccular activation. Some individuals have contralateral-crossed cVEMP responses with monaural air-conducted stimulation (ACS) which can contaminate cVEMP responses with bilateral stimulation. While the origin of the contralateral-crossed response is under debate, its presence has implications for cVEMP testing with midline bone conduction vibration (BCV).

PURPOSE

 The purpose of this study was to determine the origin of the contralateral-crossed cVEMP response. It was hypothesized that the crossed response is due to electrode contamination and would disappear with a modified electrode montage.

RESEARCH DESIGN

 This is a cross-sectional research study.

STUDY SAMPLE

 Fifteen healthy participants (30 ears; mean age: 27.4 19-39; 10 females).

DATA COLLECTION AND ANALYSIS

 Participants completed cVEMP testing using three stimulation methods (monoaural ACS, binaural ACS, and midline BCV) and two electrode montages (sternum reference and Fp reference).

RESULTS

 In the monoaural ACS with sternum reference condition, 53.3% ears had contralateral-crossed cVEMP responses that were in-phase with the ipsilateral response for all but three ears. Whereas in the monoaural ACS with Fp reference condition, 3% had a contralateral-crossed cVEMP response. ACS and BCV cVEMP corrected amplitudes were significantly larger in the sternum reference conditions, which is attributed to artificial enhancement from the in-phase contralateral-crossed responses.

CONCLUSIONS

 The significant reduction of contralateral-crossed responses in the Fp reference condition suggests that the contralateral-crossed cVEMP response is due to reference electrode contamination and may be a more appropriate reference placement when completing cVEMPs with midline BCV.

A meta-analysis comparing the performance of narrowband CE-Chirp and 500 Hz tone burst stimuli in recording cervical vestibular evoked myogenic potential (cVEMP)

Due to contradictory outcomes in the literature, the aim of this meta-analysis is to verify whether the narrowband (NB) CE-Chirp stimulus (centred at 500 Hz) would produce more robust cervical vestibular evoked myogenic potential (cVEMP) responses relative to the conventional 500 Hz tone burst. The literature search was conducted using PubMed, Scopus, and Web of Science databases and the terms used were "vestibular evoked myogenic potential" and "chirp". The cVEMP parameters to be analysed were P1 latency, N1 latency, and P1-N1 amplitude. A total of 59 potential articles were obtained from the database search. Eventually, five articles were found to be eligible for the meta-analysis (with n = 222). As found, P1 and N1 latencies of cVEMP were significantly shorter for the chirp stimulus (p < 0.001), with substantially large effect sizes. On the other hand, P1-N1 amplitude values were found to be not statistically different between the two stimuli (p = 0.189), with a small effect size. It appears that there is no indication to support the superiority of the NB CE-Chirp stimulus (centred at 500 Hz) in the cVEMP testing (relative to the conventional 500 Hz tone burst). In particular, both stimuli produce comparable P1-N1 amplitude values. Even though P1 and N1 latencies are statistically shorter for the chirp stimulus, this may not reflect that it should be the preferred stimulus for recording cVEMP responses (and the reasons for this are discussed accordingly).

Effects of Age on the Frequency Amplitude Ratio of Cervical and Ocular Vestibular Evoked Myogenic Potentials

PURPOSE

An increase in the 1000/500 Hz frequency amplitude ratio (FAR) of the cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP, respectively) may serve as a potential biomarker for diagnosing Meniere's disease (MD). However, the aging process can also result in an increased FAR for VEMPs. In older patients, distinguishing whether changes in VEMP FAR are due to MD or aging processes becomes difficult. We aimed to investigate the effects of age on VEMP FARs and establish a FAR-normative range for different age groups.

METHOD

cVEMP and oVEMP were recorded from a total of 106 participants grouped as young, middle-aged, and older adults using air-conducted tone bursts at 500, 750, and 1000 Hz at 125 dB pSPL. The FAR was calculated for the cVEMP and oVEMP for the following frequencies: FAR1 = 1000/500, FAR2 = 1000/750, and FAR3 = 750/500.

RESULTS

A significant age-related effect was observed on the cVEMP FAR. Although the oVEMP FAR showed an increasing trend with age, it was not statistically significant. Age-based normative FAR values are provided.

CONCLUSIONS

Drawing from the normative FAR from this study, there is evidence that the existing MD diagnostic criteria would misidentify a considerable number of older adults. Therefore, to reduce false positives, we recommend a more stringent cVEMP and oVEMP FAR criterion in older adults.

Investigation of Pathogenesis and Otolithic Organ Responses in Sailors with Seasickness Using cVEMP

There are different theories cited as the cause of Motion Sickness. Asymmetrical otolithic organ function is one of the etiology theories of motion sickness. In our study, the aim was to reveal whether there is a cause originating from the sacculocolic reflex pathway in the physiopathology of seasickness. The patient group included 15 man sailors with diagnosis of seasickness and the control group included 15 man sailors without seasickness in our study. Cervical evoked myogenic vestibular potential (cVEMP) findings were compared between the groups. In the right and left ears of sailors with seasickness, the mean latencies of the p13 and n23 waves at 100, 95, and 90 dB normal hearing level (nHL) levels were found significantly shorter than in the control group (p < 0.05, for all). In the seasickness group, cVEMP interaural wave amplitude asymmetry ratio at 100 nHL level were found significantly higher than the control group (p = 0.001). The findings of our study indicated that there may be reasons arising rom the sacculocolic reflex pathway in the pathophysiology of seasickness.

[Practical instructions for recording vestibular evoked myogenic potentials]

Recording of vestibular evoked myogenic potentials (VEMPs) is a well-established method for functional diagnostics of the otolith organs. VEMPs are vestibular reflexes of the sacculus und utriculus to acoustic stimulation by air-conducted sound or bone-conducted vibration and are recorded by surface electrodes from the cervical (cVEMP) and ocular (oVEMP) muscles. The results of VEMP recordings are part of the neuro-otologic test battery and enable diagnosis of various vestibular disorders or differentiation between non-vestibular and peripheral vestibular vertigo. However, the methods for recording VEMPs vary substantially, although recording and stimulation parameters as well as methods of data analysis have a significant influence on the results. This article provides an overview of recommended parameters as well as practical instructions for the recording, analysis, and interpretation of VEMPs.

Evaluating Fixed Single-Point Parameters When Applied to Vestibular Evoked Myogenic Potentials: The Effect of Single Point and Signal Window

OBJECTIVES

Several studies have applied a common objective detection algorithm (fixed single point [ Fsp ]) for detection of the vestibular evoked myogenic potential (VEMP). However, fundamental parameters of Fsp , such as establishing the location and duration of a signal window, have not been examined. In addition, Fsp criterion values used for response detection have not been established for cervical VEMPs (cVEMPs) or ocular VEMPs (oVEMPs). The purpose of this article was to investigate the effect of various single points and signal windows on Fsp , as well as determining Fsp criteria to determine response presence for cVEMP and oVEMP in a group of young healthy participants.

DESIGN

Twenty young healthy adults under the age of 30 and with no history of hearing or balance concerns were enrolled in the study protocol. Air-conducted cVEMPs and oVEMPs were evoked using 500 Hz tone bursts at 123 dB pSPL recorded at a fixed electromyography activation of 50 µV for cVEMPs and 35° gaze angle for oVEMPs. Responses were analyzed off-line using visual and objective detection. Fsp was applied to cVEMPs and oVEMPs using a range of single points and signal windows.

RESULTS

Noise variance was lowest for cVEMPs at the latency of P1, and for oVEMPs noise variance was not significantly different across the single-point latencies. On average, extending the length of the signal window lowered the Fsp value in cVEMPs and oVEMPs. An Fsp value of 2.0 was chosen as the criterion cutoff associated with the 95th percentile during no-response conditions using group data for cVEMPs and oVEMPs, respectively. Fsp values for cVEMPs and oVEMPs were not significantly different from each other.

DISCUSSION

This study established single-point latency and time-window parameters for VEMP-related applications of the Fsp detection algorithm. Fsp criteria values were established for cVEMP and oVEMP. Using these parameters, responses were detected in all participants.

Comprehensive Equilibrium Function Tests for an Accurate Diagnosis in Vertigo: A Retrospective Analysis

Background/Objectives: An accurate diagnosis of vertigo is crucial in patient care. Traditional balance function tests often fail to offer independent, conclusive diagnoses. This study aimed to bridge the gap between traditional diagnostic approaches and the evolving landscape of automated diagnostic tools, laying the groundwork for advancements in vertigo care. Methods: A cohort of 1400 individuals with dizziness underwent a battery of equilibrium function tests, and diagnoses were established based on the criteria by the Japanese Society for Vertigo and Equilibrium. A multivariate analysis identified the key diagnostic factors for various vestibudata nlar disorders, including Meniere's disease, vestibular neuritis, and benign paroxysmal positional vertigo. Results: This study underscored the complexity of diagnosing certain disorders such as benign paroxysmal positional vertigo, where clinical symptoms play a crucial role. Additionally, it highlighted the utility of specific physical balance function tests for differentiating central diseases. These findings bolster the reliability of established diagnostic tools, such as audiometry for Meniere's disease and spontaneous nystagmus for vestibular neuritis. Conclusions: This study concluded that a multifaceted approach integrating multiple diagnostic indicators is crucial for accurate clinical decisions in vestibular disorders. Future studies should incorporate novel tests, quantitative assessments, and advanced technologies to enhance the diagnostic capabilities of vestibular medicine.

Bone-Anchored Hearing Aid Effects on Vestibular Function: A Preliminary Report

OBJECTIVE

Cochlear receptors are sensitive to vibratory stimuli. Based on this sensibility, bone-anchored hearing aids have been introduced to correct unilateral or bilateral conductive or mixed hearing loss and unilateral deafness. The vestibular system is also sensitive to the vibratory stimulus and this type of response is used in clinics to test its functionality. Being aware of this double separated sensibility, we wondered whether bone vibration, which activates the acoustic receptors of patients with bone conduction aids, can also influence the functionality of the vestibular system.

METHODS

To this end, we recruited 12 patients with a bone-anchored hearing aid and evaluated their vestibular function with and without an activated vibratory acoustic device.

RESULTS

Our results show that the vibratory stimulus delivered by the bone conduction aid also reaches and stimulates the vestibular receptors; this stimulation is evidenced by the appearance or modification of some nystagmus findings during bedside vestibular testing. Despite this, none of these patients complained of dizziness or vertigo during prosthesis use. Nystagmus that appeared or changed during acoustic vibratory stimulation through the prosthesis was almost all predominantly horizontal, unidirectional with respect to gaze or body position, inhibited by fixation, and most often consistent with vestibular function tests indicating peripheral vestibular damage.

CONCLUSIONS

The findings of sound-evoked nystagmus seem to indicate peripheral rather than central vestibular activation. The occurrence of some predominantly horizontal and high-frequency induced nystagmus seems to attribute the response mainly to the utricle and lateral semicircular canal.

Myogenic artifacts masquerade as neuroplasticity in the auditory frequency-following response (FFR)

The frequency-following response (FFR) is an evoked potential that provides a "neural fingerprint" of complex sound encoding in the brain. FFRs have been widely used to characterize speech and music processing, experience-dependent neuroplasticity (e.g., learning, musicianship), and biomarkers for hearing and language-based disorders that distort receptive communication abilities. It is widely assumed FFRs stem from a mixture of phase-locked neurogenic activity from brainstem and cortical structures along the hearing neuraxis. Here, we challenge this prevailing view by demonstrating upwards of ~50% of the FFR can originate from a non-neural source: contamination from the postauricular muscle (PAM) vestigial startle reflex. We first establish PAM artifact is present in all ears, varies with electrode proximity to the muscle, and can be experimentally manipulated by directing listeners' eye gaze toward the ear of sound stimulation. We then show this muscular noise easily confounds auditory FFRs, spuriously amplifying responses by 3-4x fold with tandem PAM contraction and even explaining putative FFR enhancements observed in highly skilled musicians. Our findings expose a new and unrecognized myogenic source to the FFR that drives its large inter-subject variability and cast doubt on whether changes in the response typically attributed to neuroplasticity/pathology are solely of brain origin.

Effectiveness of the sternocleidomastoid muscle contraction asymmetry and filter: cervical vestibular evoked myogenic potential

OBJECTIVE

This study aimed to determine the precautions that can be taken to increase the reliability of the vestibular evoked myogenic potentials test without being affected by the asymmetry of the sternocleidomastoid muscle and the issues that should be considered in the interpretation of vestibular evoked myogenic potential results if these precautions are not taken.

METHOD

Individuals with sternocleidomastoid muscle activity of less than 30 μV in cervical vestibular evoked myogenic potential testing and an asymmetry ratio of more than 0.35 were excluded. In our study, individuals were divided into different groups according to sternocleidomastoid muscle asymetry.

RESULTS

A total of 53 individuals were included in the study. Intergroup comparisons were made to determine the effect of electromyogram scaling and filter use on amplitude asymmetry ratio according to sternocleidomastoid muscle asymmetry.

CONCLUSION

Keeping the sternocleidomastoid muscle asymmetry not exceeding 10 μV maximises the reliability of cervical vestibular evoked myogenic potentials. As a result of our study, it can be concluded that in clinical applications the asymmetry should not exceed 20 μV.

Audiovestibular Findings in Patients with Concurrent Superior Canal Dehiscence and Vestibular Schwannoma

OBJECTIVE

To describe the clinical-instrumental findings in case of concurrent superior canal dehiscence (SCD) and ipsilateral vestibular schwannoma (VS), aiming to highlight the importance of an extensive instrumental assessment to achieve a correct diagnosis.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Five patients with concurrent SCD and VS.

INTERVENTION

Clinical-instrumental assessment and imaging.

MAIN OUTCOME MEASURE

Clinical presentation, audiovestibular findings, and imaging.

RESULTS

The chief complaints were hearing loss (HL) and unsteadiness (80%). Other main symptoms included tinnitus (60%) and pressure-induced vertigo (40%). Mixed-HL was identified in three patients and pure sensorineural-HL in 1, including a roll-over curve in speech-audiometry in two cases. Vibration-induced nystagmus was elicited in all cases, whereas vestibular-evoked myogenic potentials showed reduced thresholds and enhanced amplitudes on the affected side in three patients. Ipsilesional weakness on caloric testing was detected in three patients and a bilateral hyporeflexia in one. A global canal impairment was detected by the video-head impulse test in one case, whereas the rest of the cohort exhibited a reduced function for the affected superior canal, together with ipsilateral posterior canal impairment in two cases. All patients performed both temporal bones HRCT scan and brain-MRI showing unilateral SCD and ipsilateral VS, respectively. All patients were submitted to a wait-and-scan approach, requiring VS removal only in one case.

CONCLUSION

Simultaneous SCD and VS might result in subtle clinical presentation with puzzling lesion patterns. When unclear symptoms and signs occur, a complete audiovestibular assessment plays a key role to address imaging and diagnosis.

Vestibulospinal reflexes elicited with a tone burst method are dependent on spatial orientation

Balance involves several sensory modalities including vision, proprioception and the vestibular system. This study aims to investigate vestibulospinal activation elicited by tone burst stimulation in various muscles and how head position influences these responses. We recorded electromyogram (EMG) responses in different muscles (sternocleidomastoid-SCM, cervical erector spinae-ES-C, lumbar erector spinae-ES-L, gastrocnemius-G, and tibialis anterior-TA) of healthy participants using tone burst stimulation applied to the vestibular system. We also evaluated how head position affected the responses. Tone burst stimulation elicited reproducible vestibulospinal reflexes in the SCM and ES-C muscles, while responses in the distal muscles (ES-L, G, and TA) were less consistent among participants. The magnitude and polarity of the responses were influenced by the head position relative to the cervical spine. When the head was rotated or tilted, the polarity of the vestibulospinal responses changed, indicating the integration of vestibular and proprioceptive inputs in generating these reflexes. Overall, our study provides valuable insights into the complexity of vestibulospinal reflexes and their modulation by head position. However, the high variability in responses in some muscles limits their clinical application. These findings may have implications for future research in understanding vestibular function and its role in posture and movement control.

Predictors of non-primary auditory and vestibular symptom persistence following surgical repair of superior canal dehiscence syndrome

Objective

Patients with superior canal dehiscence syndrome (SCDS) can present with a plethora of auditory and/or vestibular symptoms associated with a bony defect of the superior semicircular canal. While surgical repair is a reasonable option for patients with significant localizing symptoms, the degree of clinical improvement will vary among patients and poses challenges in outcome prediction. This study aims to assess the relationship between preoperative and postoperative symptoms and identify predictors of symptom persistence following repair.

Study design

Retrospective chart review.

Setting

Tertiary neurotology single-institution care center.

Main outcome measures

The primary outcome was to determine the proportion of resolved and persistent primary (most bothersome) and non-primary audiologic and vestibular symptoms following SCD repair. Secondary outcomes included comparison of patient, operative and radiologic characteristics between patients with resolved vs. persistent symptoms. Standardized patient questionnaires including 11 auditory and 8 vestibular symptoms were administered to patients at their preoperative and follow-up visits. Patient pre- vs. postoperative survey results, demographic and clinical characteristics, operative characteristics, audiometric data and cervical vestibular evoked myogenic potential (cVEMP) thresholds were compared via univariate χ2 and multivariate binary logistic regression analyses between those patients reporting full postoperative resolution of symptoms and persistence of one or more symptoms. Radiologic computed tomography (CT) measurements of superior canal dehiscence (SCD) defect size, location, and laterality were also compared between these two groups.

Results

Of 126 patients (132 ears) included in our study, 119 patients (90.2%) reported postoperative resolution (n = 82, 62.1%) or improvement (n = 37, 28.0%) of primary (most bothersome) symptoms, while 13 patients (9.8%) reported persistence of primary symptoms. The median (interquartile range) and range between surgery and questionnaire completion were 9 (4-28), 1-124 months, respectively. Analyzing all symptoms (primary and non-primary) 69 (52.3%) and 68 (51.1%) patients reported complete postoperative auditory and vestibular symptom resolution, respectively. The most likely persistent symptoms included imbalance (33/65/67, 50.8%), positional dizziness (7/20, 35.0%) and oscillopsia (44/15, 26.7%). Factors associated with persistent auditory symptoms included history of seizures (0% vs. 7.6%, p = 0.023), auditory chief complaint (50.0% vs. 70.5%), higher PTA (mean 19.6 vs. 25.1 dB, p = 0.043) and higher cervical vestibular evoked myogenic potential (cVEMP) thresholds at 1000 Hz (mean 66.5 vs. 71.4, p = 0.033). A migraine diagnosis (14.0% vs. 41.9% p < 0.010), bilateral radiologic SCD (17.5% vs. 38.1%, p = 0.034) and revision cases (0.0% vs. 14.0%, p = 0.002) were associated with persistent vestibular symptoms. Neither SCD defect size nor location were significantly associated with symptom persistence (P > 0.05).

Conclusions

Surgical repair for SCDS offers meaningful reduction in the majority of auditory and vestibular symptoms. However, the persistence of certain, mostly non-primary, symptoms and the identification of potential associated factors including migraines, PTA thresholds, cVEMP threshold, bilateral SCD, and revision cases emphasize the importance of individualized patient counseling and management strategies.

[The "difficult" patient-pearls and pitfalls of vestibular diagnostic tests: Part 2 : Difficult aspects of vestibular laboratory testing]

Patients with the cardinal symptoms "vertigo" or "dizziness" may be a real challenge for the treating otorhinolaryngologist. While the first part of this educational series was focused on history taking and bedside neurotological examination, the present paper is devoted to difficult aspects of vestibular laboratory testing, including getting the indication right, what to do if my patient is not able to fully cooperate during the tests, how to choose the adequate diagnostic procedure depending on the patient's comorbidities, how to interpret discordant results of various tests. Finally the paper addresses which conclusions can be drawn (and cannot be drawn) from normal findings in vestibular testing and how to communicate this result to the dizzy patient.

Skull Vibration-Induced Nystagmus in Superior Semicircular Canal Dehiscence: A New Insight into Vestibular Exploration-A Review

The third window syndrome, often associated with the Tullio phenomenon, is currently most often observed in patients with a superior semicircular-canal dehiscence (SCD) but is not specific to this pathology. Clinical and vestibular tests suggestive of this pathology are not always concomitantly observed and have been recently complemented by the skull-vibration-induced nystagmus test, which constitutes a bone-conducted Tullio phenomenon (BCTP). The aim of this work was to collect from the literature the insights given by this bedside test performed with bone-conducted stimulations in SCD. The PRISMA guidelines were used, and 10 publications were included and analyzed. Skull vibration-induced nystagmus (SVIN), as observed in 55 to 100% of SCD patients, usually signals SCD with greater sensitivity than the air-conducted Tullio phenomenon (ACTP) or the Hennebert sign. The SVIN direction when the test is performed on the vertex location at 100 Hz is most often ipsilaterally beating in 82% of cases for the horizontal and torsional components and down-beating for the vertical component. Vertex stimulations are more efficient than mastoid stimulations at 100 Hz but are equivalent at higher frequencies. SVIN efficiency may depend on stimulus location, order, and duration. In SCD, SVIN frequency sensitivity is extended toward high frequencies, with around 400 Hz being optimal. SVIN direction may depend in 25% on stimulus frequency and in 50% on stimulus location. Mastoid stimulations show frequently diverging results following the side of stimulation. An after-nystagmus observed in 25% of cases can be interpreted in light of recent physiological data showing two modes of activation: (1) cycle-by-cycle phase-locked activation of action potentials in SCC afferents with irregular resting discharge; (2) cupula deflection by fluid streaming caused by the travelling waves of fluid displacement initiated by sound or vibration at the point of the dehiscence. The SVIN direction and intensity may result from these two mechanisms' competition. This instability explains the SVIN variability following stimulus location and frequency observed in some patients but also discrepancies between investigators. SVIN is a recent useful insight among other bedside examination tests for the diagnosis of SCD in clinical practice.

Measurement of Ocular Vestibular Evoked Myogenic Potentials: Nasion Reference Montage as an Alternative to the Clinical Standard Montage

OBJECTIVE

To compare two novel electrode montages for ocular, vestibular evoked myogenic potential using single-nasion reference electrodes with the clinical standard montage.

STUDY DESIGN

Randomized crossover experiment.

SETTING

Tertiary referral center.

PARTICIPANTS

Sixty healthy participants.

INTERVENTION

Normal hearing and vestibular function were confirmed with an extensive test-battery. All ocular, vestibular evoked myogenic potential settings were measured with air-conducted tone bursts at 100-dB normal hearing level and a frequency of 500 Hz. Three electrode montages were measured in randomized order: the clinical standard montage ("S"), the nasion reference montage ("N"), and the nasion reference montage with a more lateral active electrode ("L"). Upgaze was standardized to 35 degrees.

MAIN OUTCOME MEASURES

Detection rate, latency of N1 and P1, peak-to-peak amplitude of N1 and P1, signal-to-noise ratio (SNR), asymmetry ratio (AR), concordance of expert assessment, and reliability.

RESULTS

All electrode montages showed detection rates greater than 90%. Latencies for "L" were shorter than for "S" and "N." Amplitudes and SNR for "S" and "N" were higher than for "L," whereas the values for "S" and "N" did not differ significantly. For AR, no significant differences between the montages were assessed. Concordance of experts ranged from 78% for "L" and 89.8% for "N." All montages provided excellent day-to-day reliability (intraclass correlation coefficient ≥0.9) for amplitudes and SNR.

CONCLUSIONS

Montage N could be a useful alternative to the clinical standard montage: although results are roughly equivalent, montage N requires one less electrode to do so.

Analysis of postural stability using foam posturography in patients with persistent postural-perceptual dizziness

BACKGROUND/OBJECTIVE

Persistent postural-perceptual dizziness (PPPD) is worsened in a standing posture, or by body movement, or visual stimulation. We aimed to evaluate postural stability in PPPD patients using foam posturography and to investigate the dependence on visual and somatosensory input in the standing posture.

METHODS

Foam posturography was performed on 53 PPPD patients, and data from the PPPD patients were compared with the data from an age- and sex-matched healthy controls. The PPPD patients were divided into four groups based on the findings of vestibular function tests and the effect of vestibular function on posturographic data was examined.

RESULTS

Romberg's ratios were significantly higher in PPPD patients than in controls. The median Romberg's ratios in PPPD patients with normal vestibular function were also higher than those in controls. However, foam ratio was significantly lower in PPPD patients than in controls. The median foam ratios in PPPD patients with vestibular dysfunction were also lower than those in controls.

CONCLUSIONS

In a standing posture, PPPD patients may be more dependent on visual input and less dependent on somatosensory input than healthy subjects. Higher dependence on visual and lower dependence on somatosensory input in PPPD may be a feature unaffected by vestibular function.

Chirp-Evoked VEMPs: A Test-Retest Reliability Study

OBJECTIVES

To determine the test-retest reliability of cervical and ocular vestibular-evoked myogenic potentials (c&oVEMP) evoked by 500 Hz narrowband (NB) CE-Chirp and broadband (BB) CE-Chirp stimuli.

DESIGN

Twenty healthy participants (10 female) were tested twice on the same day to determine the within-session reliability and 1 week later to determine the between-session reliability. The latency, amplitude, and asymmetry ratio of c&oVEMPs elicited by 95 dB nHL air-conducted (AC) 500 Hz NB CE-Chirp and BB CE-Chirp were recorded bilaterally.

RESULTS

A moderate to good between-session reliability with intraclass correlation coefficient (ICC) values ranging from 0.52 to 0.82 was observed for cVEMP latency, amplitude, and asymmetry ratio evoked by 500 Hz NB CE-Chirp, as well as for the BB CE-Chirp cVEMP amplitude (ICC of 0.70 and 0.84). In contrast, an overall poor reliability ICC values between 0.30 and 0.42 for cVEMP latency and asymmetry ratio were observed for BB CE-Chirp. For the oVEMP, overall poor between-session reliability for all response parameters evoked by the 500 Hz NB CE-Chirp and the BB CE-Chirp was observed.

CONCLUSIONS

The 500 Hz NB CE-Chirp was more reliable than the BB CE-Chirp in terms of cVEMP latency, amplitude, and asymmetry ratio. Further investigation using the standard electrode montage is necessary to assess the test-retest reliability of the chirp-evoked oVEMP.

Is vestibular function related to human hippocampal volume?

BACKGROUND

Recent studies implicate the effect of vestibular loss on cognitive decline, including hippocampal volume loss. As hippocampal atrophy is an important biomarker of Alzheimer's disease, exploring vestibular dysfunction as a risk factor for dementia and its role in hippocampal atrophy is of interest.

OBJECTIVE

To replicate previous literature on whole-brain and hippocampal volume in semicircular canal dysfunction (bilateral vestibulopathy; BV) and explore the association between otolith function and hippocampal volume.

METHODS

Hippocampal and whole-brain MRI volumes were compared in adults aged between 55 and 83 years. Participants with BV (n = 16) were compared to controls individually matched on age, sex, and hearing status (n = 16). Otolith influence on hippocampal volume in preserved semicircular canal function was evaluated (n = 34).

RESULTS

Whole-brain and targeted hippocampal approaches using volumetric and surface-based measures yielded no significant differences when comparing BV to controls. Binary support vector machines were unable to classify inner ear health status above chance level. Otolith parameters were not associated with hippocampal volume in preserved semicircular canal function.

CONCLUSIONS

No significant differences in whole-brain or hippocampal volume were found when comparing BV participants with healthy controls. Saccular parameters in subjects with preserved semicircular canal function were not associated with hippocampal volume changes.