Glycerol affects vestibular-evoked myogenic potentials and pure-tone hearing in patients with Ménière's disease

On the Relationship Between Menière's Disease and Endolymphatic Hydrops

: The relationship between Menière's disease and endolymphatic hydrops is ambiguous. On the one hand, the existence of cases of endolymphatic hydrops lacking the classic symptoms of Menière's disease has prompted the assertion that endolymphatic hydrops alone is insufficient to cause symptoms and drives the hypothesis that endolymphatic hydrops is a mere epiphenomenon. Yet, on the other hand, there is considerable evidence suggesting a relationship between the mechanical pressure effects of endolymphatic hydrops and resultant disordered auditory physiology and symptomatology. A critical appraisal of this topic is undertaken, including a review of key histopathologic data chiefly responsible for the epiphenomenon hypothesis. Overall, a case is made that A) the preponderance of available evidence suggests endolymphatic hydrops is likely responsible for some of the auditory symptoms of Menière's disease, particularly those that can be modulated by mechanical manipulation of the basilar membrane and cochlear microphonic; B) Menière's disease can be reasonably considered part of a larger spectrum of hydropic inner ear disease that also includes some cases that lack vertigo. C) The relationship with endolymphatic hydrops sufficiently robust to consider its presence a hallmark defining feature of Menière's disease and a sensible target for diagnostic detection.

Effects of Glycerol Test on Resonance Frequency in Patients with Ménière's Disease

OBJECTIVE

To evaluate resonance frequency (RF) values via dehydration effects in the inner ear caused by the glycerol test, which is used as a diagnostic method for Ménière's disease (MD).

METHODS

Twenty adult patients with unilateral MD were included in the study. Before, and then at 1, 2, and 3 h after administration of glycerol (1 g/kg), pure-tone hearing levels (125-8,000 kHz) and multifrequency tympanometry tests were performed. As a control, the RF values of the ears of 25 healthy subjects (i.e., 50 ears) were compared to the affected and unaffected ears in the 20 MD patients.

RESULTS

There was a significant difference between the RF values of affected and healthy ears before glycerol administration (p = 0.047). The RF values before and after glycerol administration into affected ears were compared. The average RF values decreased significantly from 748.0 ± 402.1 to 808.0 ± 410.1 Hz at 1 h after glycerol intake, and this value increased during the subsequent hours. There were no statistically significant differences between the pure-tone levels before and 1 h after glycerol administration, but a significant decrease was observed at 3 h.

CONCLUSION

We suggest that MD has different inner-ear dynamics and normal RF values when compared to healthy ears. Furthermore, decreased inner ear pressure causes reduction of the mass effect and a stiffening of the annular ligament. We conclude that pre- and post-RF tests should be added to the test battery for diagnosis of MD.

Correlation between Vestibular Evoked Myogenic Potentials and Disease Progression in Ménière's Disease

OBJECTIVE

To assess the relationship between ocular (oVEMPs) and cervical (cVEMPs) vestibular evoked myogenic potentials and audiometrically determined clinical stage in Ménière's disease (MD).

METHODS

Thirty-four unilateral MD patients and 30 healthy volunteers were included in the study. Pure-tone hearing levels, oVEMPs, cVEMPs, and videonystagmography results were analyzed and compared between the groups.

RESULTS

Both oVEMPs and cVEMPs were highly reproducible in the control group. At the early stages of MD, cVEMPs were particularly disturbed, while at the advanced stages both oVEMPs and cVEMPs were altered pathologically. In the study group, oVEMP and cVEMP amplitudes and interaural amplitude difference (IAD) statistically differed from those in the control sample. oVEMPs were absent in 7.7% of stage III and in 44.5% of stage IV MD patients, while cVEMPs were absent in 15.4% of stage III and in 54.5% of stage IV MD patients, respectively. In stage III and IV MD patients in whom oVEMPs and cVEMPs were obtained, IADs were increased. Caloric asymmetry was found in 64.7% of MD patients. Caloric weakness was more prominent in cases with advanced MD.

CONCLUSION

VEMPs can be used for objective validation of the stage of MD.

The Clinical Utility of Vestibular-Evoked Myogenic Potentials in the Diagnosis of Ménière's Disease

Ménière’s disease (MD) is a condition that has been proposed over 150 years ago, which involves audiological and vestibular manifestations, such as aural fullness, tinnitus, vertigo, and fluctuating hearing thresholds. Over the past few years, many researchers have assessed different techniques to help diagnose this pathology. Vestibular-evoked myogenic potential (VEMP) is an electrophysiological method assessing the saccule (cVEMP) and the utricule (oVEMP). Its clinical utility in the diagnosis of multiple pathologies, such as superior canal dehiscence, has made this tool a common method used in otologic clinics. The main objective of the present review is to determine the current state of knowledge of the VEMP in the identification of MD, such as the type of stimuli, the frequency tuning, and the interaural asymmetry ratio of the cVEMP and the oVEMP. Results show that the type of stimulation, the frequency sensitivity shift and the interaural asymmetry ratio (IAR) could be useful tool to diagnose and describe the evolution of MD. It is, however, important to emphasize that further studies are needed to confirm the utility of VEMP in the identification of MD in its early stage, using either bone-conduction vibration or air-conduction stimulation, which is of clinical importance when it comes to early intervention.

Detection of Saccular Endolymphatic Hydrops in Ménière's Disease Using a Modified Glycerol cVEMP Test in Combination With the Tuning Property Test

OBJECTIVE

To determine the optimal method for detecting saccular endolymphatic hydrops (EH) in patients with Ménière's disease (MD) using a glycerol cervical vestibular evoked myogenic potential (cVEMP) test in combination with a tuning property test.

STUDY DESIGN

Prospective patients series.

SETTING

Tertiary referral center.

PATIENTS

Twenty-three subjects (age: 36-77 years) were enrolled in this study. Seventeen subjects were diagnosed with definite MD. Six subjects were diagnosed with possible MD.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURE

The corrected amplitudes of p13-n23 (cVEMP) were measured before and after the administration of 10% glycerol (500 ml, 2 h, intravenously). A tuning property index and the p13-n23 amplitude improvement ratio were calculated.

RESULTS

The positivity rate (PR) during the tuning property test was 55% (definite MD-affected ears), 35% (definite MD-unaffected ears), and 25% (possible MD ears). The PR during the glycerol cVEMP amplitude test was 60, 8, and 0%, respectively. The use of modified criteria for the glycerol cVEMP test in combination with the tuning property test resulted in the PR increasing to 75, 57, and 25%, respectively. The pre-glycerol stage results obtained using the tuning property test almost (except in two ears) completely agreed with the glycerol cVEMP test results by the modified criteria.

CONCLUSION

The tuning property test is an easy and useful way of detecting saccular EH. However, the glycerol cVEMP test is required in patients that do not respond to either 500 or 1000 Hz short tone bursts (STB).