Vestibular evoked myogenic potentials: review

Nondestructive and objective assessment of the vestibular function in rodent models: A review

The normal function of the vestibular system is crucial for the sense of balance. The techniques used to assess the vestibular function plays a vital role in the research of the vestibular system. In this article, we have systematically reviewed some popular methods employing vestibular reflexes and vestibular evoked potentials for assessing the vestibular function in rodent models. These vestibular reflexes and vestibular evoked potentials to effective stimuli have been used as nondestructive and objective functional measures. The main types of vestibular reflexes include the vestibulo-ocular reflex (VOR), vestibulocollic reflex (VCR), and vestibulo-sympathetic reflex (VSR). They are all capable of indicating the functions of the semicircular canals and otoliths. However, the VOR assessment is much more prevalently used because of the relatively stereotypical inputoutput relationship and simple motion pattern of the ocular response. In contrast, the complicated motion pattern and small gain of the VCR response, as well as the undesired component possibly contributed from the acceleration receptors outside the labyrinths in the VSR response, restrict the widespread applications of VCR and VSR in the assessment of the vestibular system. The vestibular evoked myogenic potentials (VEMPs) and vestibular sensory evoked potentials (VsEPs) are the two typical evoked potentials that have been also employed for evaluating the vestibular function. Through exploiting different types of the VEMPs, the saccular and utricular functions can be evaluated separately. The sound-induced VEMPs, moreover, are capable of noninvasively assessing the unilateral vestibular function. The VsEPs, via the morphology of their signal waveforms, enable the access to the location-specific information that indicates the functional statuses of different components within the vestibular neural pathway.

Clinical value of vestibular-evoked myogenic potential tests in patients with sudden sensorineural hearing loss

Background

This study aims to investigate the clinical value of two kinds of vestibular-evoked myogenic potentials in patients with sudden sensorineural hearing loss (SSNHL).

Methods

A total of 82 patients were divided into two groups: vertigo group and non-vertigo group. All patients underwent examinations for pure tone hearing thresholds, middle ear analysis, the videonystagmography, caloric tests, and vestibular-evoked myogenic potentials elicited from the sternocleidomastoid and extraocular muscle. In addition, 30 healthy subjects were selected as the control group.

Results

For the 30 healthy subjects, the average latency of p13 and n23 of the cervical vestibular evoked myogenic potentials (cVEMPs) were 13.13 ± 2.89 ms and 23.51 ± 3.25 ms, respectively, and the bilateral amplitude asymmetry rate ranged within 0.05–0.31. The average latency of n10 of the ocular vestibular evoked myogenic potentials (oVEMPs) was 10.13 ± 0.48 ms. The average amplitude of the n10-p15-wave was 5.58 ± 0.65 μV. Among the 35 vertigo patients with SSNHL, 27 patients had normal cVEMP and oVEMP examination results, five patients had abnormal oVEMP examination results, and five patients had abnormal cVEMP examination results. The latency and amplifier of oVEMPs and cVEMPs were within the normal range in 47 SSNHL patients without vertigo. The chi-square value was 5.647, the P-value was equal to 0.017, and the difference was statistically significant at a confidence interval of 95%.

Conclusions

OVEMPs and cVEMPs can be used evaluate the vestibular nerve function of SSNHL patients with vertigo.

The Relationship between the Etiology of Profound Prelingual Sensorineural Hearing Loss and the Results of Vestibular-Evoked Myogenic Potentials

Introduction  Cervical vestibular-evoked myogenic potentials (cVEMPs) are biphasic, short latency potentials, which represent the inhibition of the contraction of the sternocleidomastoid muscle (SCM) mediated by the saccule, the inferior vestibular nerve, the vestibular nuclei and the medial vestibular spinal tract.

Objective  To evaluate the response of cVEMPs in individuals with profound prelingual bilateral cochlear hearing loss.

Methods  A prospective case-control study. A total of 64 volunteers, divided into a study group (31 patients with profound prelingual sensorineural hearing loss) and a control group (33 subjects matched for age and gender with psychoacoustic thresholds of ≤ 25 dB HL between 500 and 8,000 Hz) were submitted to the cVEMP exam. The causes of hearing loss were grouped by etiology and the involved period.

Results  The subjects of the study group are more likely to present changes in cVEMPs compared to the control group (35.5% versus 6.1% respectively; p  = 0.003), with an odds ratio (OR) of 8.52 ( p  = 0.009). It means that they had 8.52-fold higher propensity of presenting altered cVEMP results. There were no statistically significant differences between the latencies, the interamplitude and the asymmetry index. Regarding the etiology, there was a statistically significant difference when the cause was infectious, with an OR of 15.50 ( p  = 0.005), and when the impairment occurred in the prenatal period, with an OR of 9.86 ( p  = 0.009).

Conclusion  The present study showed abnormalities in the sacculocolic pathway in a considerable portion of individuals with profound prelingual sensorineural hearing loss due to infectious and congenital causes, as revealed by the cVEMP results.

Combined ocular and cervical vestibular evoked myogenic potential in individuals with vestibular hyporeflexia and in patients with Ménière's disease

INTRODUCTION

The vestibular evoked myogenic potential is a potential of mean latency that measures the muscle response to auditory stimulation. This potential can be generated from the contraction of the sternocleidomastoid muscle and also from the contraction of extraocular muscles in response to high-intensity sounds. This study presents a combined or simultaneous technique of cervical and ocular vestibular evoked myogenic potential in individuals with changes in the vestibular system, for use in otoneurologic diagnosis.

OBJECTIVE

To characterize the records and analyze the results of combined cervical and ocular VEMP in individuals with vestibular hyporeflexia and in those with Ménière's disease.

METHODS

The study included 120 subjects: 30 subjects with vestibular hyporeflexia, 30 with Ménière's disease, and 60 individuals with normal hearing. Data collection was performed by simultaneously recording the cervical and ocular vestibular evoked myogenic potential.

RESULTS

There were differences between the study groups (individuals with vestibular hyporeflexia and individuals with Ménière's disease) and the control group for most of wave parameters in combined cervical and ocular vestibular evoked myogenic potential. For cervical vestibular evoked myogenic potential, it was observed that the prolongation of latency of the P13 and N23 waves was the most frequent finding in the group with vestibular hyporeflexia and in the group with Ménière's disease. For ocular vestibular evoked myogenic potential, prolonged latency of N10 and P15 waves was the most frequent finding in the study groups.

CONCLUSION

Combined cervical and ocular vestibular evoked myogenic potential presented relevant results for individuals with vestibular hyporeflexia and for those with Ménière's disease. There were differences between the study groups and the control group for most of the wave parameters in combined cervical and ocular vestibular evoked myogenic potential.

Cervical vestibular evoked myogenic potentials in children

Introduction

Cervical vestibular evoked myogenic potential is a test used in neurotological examination. It verifies the integrity of vestibular function through a muscular response evoked by an acoustic stimulation which activates the saccular macula. Normal standards in adults have been established, however, there are few published data on the normal responses in children.

Objective

To establish normal standards for vestibular myogenic responses in children without neurotological complaints.

Methods

This study's design is a cohort with cross-sectional analysis. The sample consisted of 30 subjects, 15 females (50%) and 15 males (50%).

Results

The age of the subjects ranged between 8 and 13 years, with a mean of 10.2 (± 1.7). P1 peak showed an average latency of 17.26 (± 1.78) ms and a mean amplitude of 49.34 (± 23.07) μV, and the N2 peak showed an average latency of 24.78 (± 2.18) ms and mean amplitude of 66.23 (± 36.18) μV. P1–N2 mean amplitude was 115.6 (± 55.7) μV. There were no statistically significant differences when comparing by gender or by laterality.

Conclusion

We established normal values of cervical myogenic vestibular responses in children between 8 and 13 years without neurotological complaints.

Vestibular evoked myogenic potentials in pediatric patients with familial Mediterranean fever

OBJECTIVES

We aimed to investigate whether the chronic autoinflammatory process in familial Mediterranean fever (FMF), which affects numerous systems, results in vestibular dysfunction in pediatric patients being followed up for diagnosis of FMF using VEMP recordings.

METHODS

30 patients (60 ears) diagnosed with FMF and 20 (40 ears) healthy volunteers were included in the study. Following routine ear, nose, and throat examination, transient-evoked otoacoustic emissions (TEOAE) and vestibular-evoked myogenic potential (VEMP) tests were performed.

RESULTS

A total of 30 FMF pediatric patients (13 male, 17 female) and 20 controls (8 male, 12 female) were included in the study. The mean age of FMF patients was 12.13 ± 2.88 years, while that of the controls was 12.90 ± 2.80 years. All of the otoacoustic emission results of the patient and control groups were "pass VEMP recordings received in both ears of patients with FMF (60 ears) and both ears of controls (40 ears). There was no statistically significant difference for latencies or amplitudes for either patients or controls (p > 0.05).

CONCLUSION

In order to research the effect of FMF on vestibular functions, we measured VEMP. However, we did not detect alterations of VEMP in FMF patients.

Difference of diagnostic rates and analytical methods in the test positions of vestibular evoked myogenic potentials

OBJECTIVE

To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo.

METHODS

Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation.

RESULTS

Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low.

CONCLUSION

Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test.