Blog Archives

Ménière’s Disease: A Challenging and Relentless Disorder

Ménière’s disease (MD) is characterized by episodic vertigo, fluctuating hearing loss and tinnitus, and by the presence of endolymphatic hydrops on postmortem examination. This disease continues to be a diagnostic and therapeutic challenge. Patients with MD range from minimally symptomatic, highly functional individuals to severely affected, disabled patients. Current management strategies are designed to control the acute and recurrent vestibulopathy but offer minimal remedy for the progressive cochlear dysfunction. Recent research highlights the role of neurotoxicity in the pathogenesis of the cochleovestibular deterioration. This article discusses a patient with MD, and provides an algorithm for the management of this disease.

from Otolaryngologic Clinics of North America

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Meniere’s disease: Still a mystery disease with difficult differential diagnosis

One hundred and forty-six years after its first description, the differential diagnosis of Meniere’s disease remains very challenging. The aim of the present study is to review the current knowledge on the advantages and disadvantages of the new diagnostic methods for Meniere’s disease. The importance of accurate diagnosis for primary healthcare systems is also discussed. An extensive search of the literature was performed in Medline and other available database sources. Information from electronic links and related books were also included. Controlled clinical studies, prospective cohort studies, retrospective cohort studies, cross-sectional studies, case reports, written guidelines, systematic reviews, and books were selected. The typical clinical triad of symptoms from the vestibular and cochlear systems (recurrent vertigo, fluctuating sensorineural hearing loss and tinnitus) is usually the key for clinical diagnosis. Glycerol dehydration test and electrocochleography are the main diagnostic tests in current practice, while vestibular evoked myogenic potentials may be used in disease staging. Imagine techniques are not specific enough to set alone the diagnosis of Meniere’s disease, although they may be necessary to exclude other pathologies. Recently developed 3D MRI protocols can delineate the perilymphatic/endolymphatic spaces of the inner ear and aid diagnosis. Meniere’s disease is a continuous problem for the patients and affects their quality of life. Taking into account the frequent nature of the disease in certain countries, efforts for reliable diagnosis, prompt referral, and successful management are undoubtedly cost-effective for healthcare systems.

from the Annals of Indian Academy of Neurology

Additional heterozygous 2507A>C mutation of WFS1 in progressive hearing loss at lower frequencies

Objectives/Hypothesis:
To describe the audiological profiles in a Japanese family with autosomal dominant hereditary sensorineural hearing loss (SNHL) and to identify the causative gene.

Study Design:
A family study at an academic tertiary referral center.

Methods:
A family with autosomal dominant hereditary SNHL was enrolled. Hearing loss (HL) of affected members showed mid-frequency SNHL in childhood and progressed at lower frequencies with age, resulting in low-frequency SNHL. To understand the pathology of HL of this family, we performed a genetic analysis of WFS1, TECTA, and GJB2 by direct sequencing, and further audiovestibular examinations, including speech audiometry, distortion product otoacoustic emissions, electrocochleography, auditory brainstem responses, and electronystagmography for some affected members.

Results:
A heterozygous A-to-C nucleotide transversion (c.2507A>C), resulting in a lysine-to-threonine substitution at codon 836 (K836T) was identified in exon 8 of WFS1. K836T was segregated with HL in the 15 participants in the genetic study but was not detected in the 212 normal chromosomes. Only polymorphic changes were detected in TECTA and GJB2. Audiovestibular examinations indicated purely cochlear HL and normal vestibular function. The summating potential/action potential ratios in electrocochleography increased in the bilateral ears of the proband.

Conclusions:
The family described with autosomal dominant inheritance of K836T of the WFS1 gene demonstrates a progressive hearing loss in the lower frequencies. Laryngoscope, 2009

Image evaluation of endolymphatic space in fluctuating hearing loss without vertigo

Abstract The objective of the present study was to investigate endolymphatic space images in patients with fluctuating hearing loss without vertigo, and to elucidate its underlying pathophysiology. Eight patients with fluctuating hearing loss without vertigo were included in this study. 3T MRI was taken, 24 h after intratympanic injection of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Electrocochleography and VEMP tests were performed to evaluate cochlear and vestibular functions. Endolymphatic hydrops were observed both in the cochlea and in the vestibule of all eight patients. Three patients out of six whose summating potential/action potential (SP/AP) ratio was recordable showed an elevation of SP/AP ratio. In the two patients with remarkable endolymphatic hydrops in the vestibule, VEMP was absent from the affected ear. In conclusion, 3T MRI after intratympanic injection of Gd-DTPA revealed endolymphatic hydrops both in the cochlea and in the vestibule in the patients with fluctuating hearing loss without vertigo.

from ORL -Journal for Oto-Rhino-Laryngology and Its Related Specialties

Image evaluation of endolymphatic space in fluctuating hearing loss without vertigo

Abstract The objective of the present study was to investigate endolymphatic space images in patients with fluctuating hearing loss without vertigo, and to elucidate its underlying pathophysiology. Eight patients with fluctuating hearing loss without vertigo were included in this study. 3T MRI was taken, 24 h after intratympanic injection of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Electrocochleography and VEMP tests were performed to evaluate cochlear and vestibular functions. Endolymphatic hydrops were observed both in the cochlea and in the vestibule of all eight patients. Three patients out of six whose summating potential/action potential (SP/AP) ratio was recordable showed an elevation of SP/AP ratio. In the two patients with remarkable endolymphatic hydrops in the vestibule, VEMP was absent from the affected ear. In conclusion, 3T MRI after intratympanic injection of Gd-DTPA revealed endolymphatic hydrops both in the cochlea and in the vestibule in the patients with fluctuating hearing loss without vertigo.

from the European Archives of Oto-Rhino-Laryngologyl

Non-invasive measurements of intralabyrinthine pressure changes by electrocochleography and otoacoustic emissions

Abstract
By varying the mechanical load on the stapes footplate, intralabyrinthine pressure (ILP) influences the stiffness of the middle ear and modifies its transfer function. This results in a characteristic phase shift of the otoacoustic emissions (OAEs) around 1 kHz [Buki, B., Avan, P., Lemaire, J.J., Dordain, M., Chazal, J., Ribari, O., 1996. Otoacoustic emissions: a new tool for monitoring intracranial pressure changes through stapes displacements. Hear. Res. 94, 125–139]. This finding provides non-invasive means of monitoring changes of ILP and indirectly of intracranial pressure. Yet the vulnerability of OAEs to sensorineural hearing loss excludes many patients from being monitored in this manner. Being dependent on the middle-ear transfer function, the phase of the cochlear microphonic potential (CM) around 1 kHz should also respond to ILP changes while being less affected by impaired hearing than OAEs. Here, normal volunteers were subjected to body tilt resulting in stepwise changes in their intracranial pressure and ILP. Their CM around 1 kHz was recorded by extratympanic electrocochleography and its dependence on body position was compared to that of distortion-product OAEs. The posture-induced CM changes were also monitored in ears with sensorineural deafness and impaired OAEs to assess the usefulness of CM in the presence of hearing impairment. Last, OAEs and CM were simultaneously monitored in gerbils during intracranial pressure changes brought about via an intracranial catheter. The phase and level shifts induced by body tilt in man and intracranial pressure changes in gerbils showed up both in distortion-product OAEs and CM with similar time courses. In normally-hearing subjects, the mean phase shifts reached 16.3° for CM and 41.6° for OAEs, and CM remained large enough in hearing-impaired subjects for ILP to be monitored. The ratio of about two of OAEs to CM phase shifts matched the prediction of middle-ear models allowing for the fact that CM does not travel back through the middle ear while OAEs do. It follows that CM phase around 1 kHz provides non-invasive access to ILP changes even if OAEs cannot be measured due to sensorineural hearing loss.

from Hearing Research

Non-invasive Measurements of Intralabyrinthine Pressure Changes by Electrocochleography and Otoacoustic Emissions

By varying the mechanical load on the stapes footplate, intralabyrinthine pressure (ILP) influences the stiffness of the middle ear and modifies its transfer function. This results in a characteristic phase-shift of the otoacoustic emissions (OAEs) around 1 kHz (Büki et al. 1996). This finding provides non-invasive means of monitoring changes of ILP and indirectly of intracranial pressure. Yet the vulnerability of OAEs to sensorineural hearing loss excludes many patients from being monitored in this manner. Being dependent on the middle-ear transfer function, the phase of the cochlear microphonic potential (CM) around 1 kHz should also respond to ILP changes while being less affected by impaired hearing than OAEs. Here, normal volunteers were subjected to body tilt resulting in stepwise changes in their intracranial pressure and ILP. Their CM around 1 kHz was recorded by extratympanic electrocochleography and its dependence on body position was compared to that of distortion-product OAEs. The posture-induced CM changes were also monitored in ears with sensorineural deafness and impaired OAEs to assess the usefulness of CM in the presence of hearing impairment. Last, OAEs and CM were simultaneously monitored in gerbils during intracranial pressure changes brought about via an intracranial catheter. The phase and level shifts induced by body tilt in man and intracranial pressure changes in gerbils showed up both in distortion-product OAEs and CM with similar time courses. In normally hearing subjects, the mean phase shifts reached 16.3° for CM and 41.6° for OAEs, and CM remained large enough in hearing impaired subjects for ILP to be monitored. The ratio of about 2 of OAEs to CM phase shifts matched the prediction of middle-ear models allowing for the fact that CM does not travel back through the middle ear while OAEs do. It follows that CM phase around 1 kHz provides non-invasive access to ILP changes even if OAEs cannot be measured due to sensorineural hearing loss.

from Hearing Research