Pathophysiology of M??ni??re's Syndrome: Are Symptoms Caused by Endolymphatic Hydrops?

Merchant, Saumil N.; Adams, Joe C.; Nadol, Joseph B.

doi:10.1097/00129492-200501000-00013

Cited by 478 publications

(362 citation statements)

References 36 publications

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“…Chermak and Dengerink 1987). This is supported by the findings in several other publications (Lindsay and Von Schulthess 1958;Lindsay et al 1967;Merchant 2010) where it was reported that only about 10 % of the cochleae from Ménière's disease patients (typically also suffering from tinnitus) showed significant loss of hair cells and cells of the spiral ganglion at the apex despite having all symptoms of Ménière's disease. Intense LF sound (30 Hz, 100 dB SPL, presented continuously for up to 24 h) has been shown to leave spiral ganglion cells intact and to not affect cochlear function in chinchillas (Harding et al 2007) 24 h post-exposure.…”

Section: Lf Sound-induced Transient Sound Perceptionssupporting

confidence: 71%

“…Endolymphatic hydrops is the primary histopathological correlate of Ménière's disease, a condition affecting the inner ear and causing hearing loss, recurrent, spontaneous episodic vertigo, aural fullness and tinnitus (Monsell et al 1995). It is, however, unclear if endolymphatic hydrops represents cause or effect of Ménière's disease (Merchant et al 2005;Berlinger 2011).…”

Section: Introductionmentioning

confidence: 99%

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Multiple Indices of the ‘Bounce’ Phenomenon Obtained from the Same Human Ears

Drexl

Überfuhr

Weddell

et al. 2013

JARO

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Loud low-frequency sounds can induce temporary oscillatory changes in cochlear sensitivity, which have been termed the 'bounce' phenomenon. The origin of these sensitivity changes has been attributed to slow fluctuations in cochlear homeostasis, causing changes in the operating points of the outer hair cell mechanoelectrical and electro-mechanical transducers. Here, we acquired three objective and subjective measures resulting in a comprehensive dataset of the bounce phenomenon in each of 22 normal-hearing human subjects. We analysed the level and phase of cubic and quadratic distortion product otoacoustic emissions and the auditory thresholds before and after presentation of a low-frequency stimulus (30 Hz sine wave, 120 dB SPL, 90 s) as a function of time. In addition, the perceived loudness of temporary, tinnitus-like sensations occurring in all subjects after cessation of the low-frequency stimulus was tracked over time. The majority of the subjects (70 %) showed a significant, biphasic change of quadratic, but not cubic, distortion product otoacoustic emissions of about 3-4 dB. Eighty-six percent of the tested subjects showed significant alterations of hearing thresholds after low-frequency stimulation. Four different types of threshold changes were observed, namely monophasic desensitisations (the majority of cases), monophasic sensitisations, biphasic alterations with initial sensitisation and biphasic alterations with initial desensitisation. The similar duration of the three bounce phenomenon measures indicates a common origin. The current findings are consistent with the hypothesis that slow oscillations of homeostatic control mechanisms and associated operating point shifts within the cochlea are the source of the bounce phenomenon.

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Section: Lf Sound-induced Transient Sound Perceptionssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Multiple Indices of the ‘Bounce’ Phenomenon Obtained from the Same Human Ears

Drexl

Überfuhr

Weddell

et al. 2013

JARO

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“…Conversely, nearly onethird of the cases of idiopathic hydrops show no association with the classic symptoms of Meniere's syndrome. 33 In addition, previous histopathological examinations have revealed that the contralateral ears of patients with unilateral Meniere's disease showed asymptomatic saccular hydrops in around 30% of patients. 34,35 Recently, Kato et al 36 reported that there was no significant association between the degree of EH and caloric responses, using MRI.…”

Section: Discussionmentioning

confidence: 98%

Morphological and functional changes in a new animal model of Ménière's disease

Egami

Kakigi

Sakamoto

et al. 2013

Laboratory Investigation

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The purpose of this study was to clarify the underlying mechanism of vertiginous attacks in Ménière's disease (MD) while obtaining insight into water homeostasis in the inner ear using a new animal model. We conducted both histopathological and functional assessment of the vestibular system in the guinea-pig. In the first experiment, all animals were maintained 1 or 4 weeks after electrocauterization of the endolymphatic sac of the left ear and were given either saline or desmopressin (vasopressin type 2 receptor agonist). The temporal bones from both ears were harvested and the extent of endolymphatic hydrops was quantitatively assessed. In the second experiment, either 1 or 4 weeks after surgery, animals were assessed for balance disorders and nystagmus after the administration of saline or desmopressin. In the first experiment, the proportion of endolymphatic space in the cochlea and the saccule was significantly greater in ears that survived for 4 weeks after surgery and were given desmopressin compared with other groups. In the second experiment, all animals that underwent surgery and were given desmopressin showed spontaneous nystagmus and balance disorder, whereas all animals that had surgery but without desmopressin administration were asymptomatic. Our animal model induced severe endolymphatic hydrops in the cochlea and the saccule, and showed episodes of balance disorder along with spontaneous nystagmus. These findings suggest that administration of desmopressin can exacerbate endolymphatic hydrops because of acute V2 (vasopressin type 2 receptor)-mediated effects, and, when combined with endolymphathic sac dysfunction, can cause temporary vestibular abnormalities that are similar to the vertiginous attacks in patients with MD. Ménière's disease (MD) is a well-known inner ear disorder characterized by symptoms including recurring attacks of vertigo typically lasting for hours, fluctuating sensorineural hearing loss, and tinnitus. Since the milestone findings on the temporal bones of MD patients, 1,2 endolymphatic hydrops (EH) has been considered as the histopathological origin of MD, as characteristic morphological changes were reported to be produced by surgical obstruction of the endolymphatic sac (ES) in guinea-pig. 3 This observation indicates that malabsorption of endolymph in the ES is one of the possible mechanisms underlying the development of EH. This experimentally induced EH has been frequently used as an animal model to investigate the pathogenesis of inner ear disorders associated with EH. In terms of vestibular function, while canal dysfunction and/or spontaneous nystagmus have been occasionally observed in this animal model, 4,5 episodes of vertiginous attack or balance disorder have only rarely been observed. 6 In other words, this model is insufficient for fully representing the common symptoms of MD.Water homeostasis of the inner ear is essential for maintaining the functions of hearing and balance. EH is considered to be the result of disruption of inner ear water homeostasis, which ...

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“…Histologically, Meniere's disease is characterized by endolymphatic hydrops and swelling of the endolymphatic space of the inner ear, 15 but the etiology and pathophysiology of endolymphatic hydrops are unknown. 16 Whether the swelling affects or injures the vestibular end organs is also unknown, but many patients with Meniere's disease have vestibular deficits as assessed by electronystagmography.…”

Section: Cell Viability and Availabilitymentioning

confidence: 99%

An in vitro model system to study gene therapy in the human inner ear

et al. 2007

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The confined fluid-filled labyrinth of the human inner ear presents an opportunity for introduction of gene therapy reagents designed to treat hearing and balance dysfunction. Here we present a novel model system derived from the sensory epithelia of human vestibular organs and show that the tissue can survive up to 5 days in vitro. We generated organotypic cultures from 26 human sensory epithelia excised at the time of labyrinthectomy for intractable Meniere's disease or vestibular schwannoma. We applied multiply deleted adenoviral vectors at titers between 10 5 and 10 8 viral particles/ml directly to the cultures for 4-24 h and examined the tissue 12-96 h post-transfection. We noted robust expression of the exogenous transgene, green fluorescent protein (GFP), in hair cells and supporting cells suggesting both were targets of adenoviral transfection. We also transfected cultures with a vector that carried the genes for GFP and KCNQ4, a potassium channel subunit that causes dominant-progressive hearing loss when mutated. We noted a positive correlation between GFP fluorescence and KCNQ4 immunolocalization. We conclude that our in vitro model system presents a novel and effective experimental paradigm for evaluation of gene therapy reagents designed to restore cellular function in patients who suffer from inner ear disorders.

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Pathophysiology of M??ni??re's Syndrome: Are Symptoms Caused by Endolymphatic Hydrops?

Abstract: Endolymphatic hydrops should be considered as a histologic marker for Meniere's syndrome rather than being directly responsible for its symptoms.

Cited by 478 publications

References 36 publications

Multiple Indices of the ‘Bounce’ Phenomenon Obtained from the Same Human Ears

Multiple Indices of the ‘Bounce’ Phenomenon Obtained from the Same Human Ears

Morphological and functional changes in a new animal model of Ménière's disease

An in vitro model system to study gene therapy in the human inner ear

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