Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cochlear Diseases”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1997

[Influence of hypoxia on the human auditory system].

The present paper presents a review of the literature on "hypoxia and human auditory mechanisms". It examines and discusses, above all, the results obtained in the various studies using pure tone audiometry and auditory evoked potentials. At the present time, the two areas which appear most sensitive to hypoxia are the cochlea and, above all, the telencephalic auditory cortex (specifically those sectors dedicated to cognitive processing of auditory stimulation). However, many other areas which are sensitive to hypoxia, but to a lesser extent, have also been identified, even in other sectors of the auditory pathway. Particularly worthy of note is the effectiveness of the metabolic compensatory mechanisms which come into play upon hypoxic stress. These mechanisms include vasodilation and the presence of metabolic reservoirs. Nevertheless, there are still a number of open questions regarding how the auditory pathway functions in the case of hypoxia; thus the experimental study of hypoxic hypoxia is still an interesting, fruitful research field in audiology.

Auditory Cortex↗
PubMed1998

Cochlear ossification after meningitis.

OBJECTIVE: This study aimed to assess the pathologic processes that result in ossification of the cochlear lumen after bacterial meningitis. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at a tertiary referral center. PATIENTS: Profoundly deaf postmeningitic patients who underwent cochlear implantation were studied. INTERVENTIONS: Diagnostic and therapeutic observations were performed. MAIN OUTCOME MEASURES: The extent of cochlear ossification is classified and related to age at which infection occurred, cerebrospinal fluid leukocyte count, Gram's stain, organism, and delay between meningitis and implantation. The extent of ossification noted on high-definition computed tomographic (CT) scan is compared with surgical findings and related to the time delays between meningitis, imaging, and surgery. RESULTS: Ossification fell into three groups: gross ossification of the scala tympani and variable amounts of the scala vestibuli; partial ossification localized to the basal turn of the scala tympani; and no ossification. There was no correlation between the extent of ossification and the age when infected, type of pathogen, cerebrospinal fluid leukocyte count, and time delay between meningitis and implantation. Visualization of bacteria on Gram's stain was a highly sensitive measure of ossification (0.93) but was not specific (0.6) with positive and negative predictive values of 0.76 and 0.86, respectively. High-definition CT underestimated the extent of ossification in 50% of cases when performed within 6 months of meningitis. CONCLUSIONS: Ossification is either gross or localized to the basal turn of the scala tympani. If ossification does occur, it is rapid and complete within a few months of infection. The visualization of bacteria on Gram's stain is a sensitive indicator for the presence of ossification but has low specificity. High-definition CT, if performed within the first 6 months of meningitis, can be an inaccurate diagnostic tool and therefore should be performed as close to the date of surgery as possible.

Adolescent↗
PubMed2000

Evaluation of the vestibular aqueduct in vestibulocochlear disorders by magnetic resonance imaging.

The visibility of the vestibular aqueduct (VA) was examined using magnetic resonance imaging (MRI) in 95 patients: 15 patients with Meniere's disease, 4 with vestibular Meniere's disease, 4 with cochlear Meniere's disease and 72 patients with other vestibular and/or cochlear disorders. In order to visualize the VA, the T2-weighted image (T2WI) and the proton-density weighted image (PDWI) were obtained in the sagittal plane with a head coil. The visibility of the VA was classified into 4 grades, i.e. grade 0 (not visible), grade 1 (partially visible with PDWI), grade 2 (partially visible with T2WI) and grade 3 (clearly visible with T2WI). The visibility of the VA was significantly lower bilaterally in Meniere's disease, vestibular Meniere's disease, cochlear Meniere's disease and idiopathic bilateral sensorineural hearing loss (IBSNHL) than in the other diseases. The differences among Meniere's disease, vestibular Meniere's disease and cochlear Meniere's disease were not significant. The significance of decreased visibility in IBSNHL is unknown so far. The VA studies using MRI strongly suggest that the pathogenesis of Meniere's disease, vestibular Meniere's disease, cochlear Meniere's disease and IBSNHL is, at least in part, related to the findings of the VA.

Adolescent↗
PubMed1999

[Imaging of the cochleo-vestibular system].

This article will review the main pathologies affecting the vestibulocochlear system from the sensorineural organs to the cerebral cortex. MR imaging has greatly improved detection of these pathologies. Thin slice MR imaging using different pulse sequences now allows improved depiction of anatomical structures. Vestibular schwannoma is by far the most common lesion, but MR imaging allows detection and characterization of rarer lesions in patients often presenting with similar symptoms.

Brain Diseases↗
PubMed1994

Pressure test for the diagnosis of Menière's disease.

In the last 15 years, a pressure chamber able to generate negative air pressure has been used to treat patients with Menière's disease. In this study we sought to clarify whether the underpressure chamber can be used to diagnose Menière's disease. We studied 45 ears from patients with neurotological diseases. The subjects were placed supine in a soundproof pressure chamber. The pressure was first decreased to -500 mmH2O, and after 5 min to -700 mmH2O. The pressure was kept at this level for another 5 min and then increased to 0 mmH2O. This procedure was done three times in succession. While the chamber pressure was below 0 mmH2O, the subjects were instructed to abstain from actively equilibrating middle ear pressure. When the chamber pressure was raised to 0 mmH2O, they were instructed to equilibrate middle ear pressure, and if necessary Politzerization or catheterization of the Eustachian tube was done. As a result, hearing was improved after this procedure only in patients with Menière's disease (50%) and/or cochlear Menière's disease (32%) in which endolymphatic hydrops was suspected.

Acoustic Impedance Tests↗
PubMed1979

Cochleo-vestibular correlations in Meniere's disease.

The cochlear and vestibular functions were investigated in a sample of 36 patients with unilateral Meniere's disease. Caloric reactions and hearing thresholds were compared separately at several frequencies. A topodiagnostic relationship between the cochlear and vestibular function was discovered. Using four qualitative categories, a significantly high correlation was obtained between the basal hearing loss (4000 Hz) and unilateral weakness, whereas no correlation was obtained when evaluating the more apical hearing loss (lower frequencies 250-1 000 Hz). A normal caloric reaction can be reasonably expected in cases of unilateral Meniere's disease if the hearing loss is less than approx. 40 dB HL at 4 000 Hz.

Adolescent↗
PubMed2004

Cochlear implant failure: is an auditory brainstem implant the answer?

OBJECTIVE: To investigate the auditory rehabilitative results achieved in five patients with cochlear implants (CIs) who subsequently received, due to poor results, auditory brainstem implants (ABIs). MATERIAL AND METHODS: Between April 1997 and March 2003, 37 patients (age range 14 months to 70 years) were fitted with ABIs in our ENT Department. Fourteen subjects had neurofibromatosis type 2 and 23 were non-tumor patients who had cochlea or cochlear nerve disease. Five subjects had previously been treated with a CI and received an ABI owing to the poor results achieved. One child had bilateral undiagnosed cochlear nerve aplasia and one was suffering from auditory neuropathy; three adults had total cochlear ossification. RESULTS: The open-set sentence recognition score (auditory-only mode) 6-8 months after ABI activation ranged from 0% to 100% in adults. In 1 subject the speech-tracking score was 56 words/min with the ABI. The two children who had achieved no hearing ability with their CI were able to detect sounds and words as early as 3 months after activation of the ABI. CONCLUSION: CI failure as a result of anatomical abnormalities can be remedied by an ABI.

Adolescent↗
PubMed1994

Ototoxicity.

This article describes the pathophysiology of ototoxic agents and contains a list of potential ototoxic agents including a list of animal species in which the toxicity has been documented or research studies performed.

Animals↗
PubMed1994

Adoptive transfer of an autoimmunological labyrinthitis in the guinea pig; animal model for a sympathetic cochleolabyrinthitis.

Sensorineural hearing loss is a common problem in the otolaryngologist's practice, with autoimmune disease of the inner ear being one possible cause. The restoration of auditory function in some patients following immunosuppressive therapy has created a desire to define and understand this disease better. Because of the lack of a well defined detection method to identify this entity clinically, this study was undertaken in order to provide an animal model for autoimmune disease of the inner ear. Previous studies with guinea pigs have demonstrated that sensitized lymphocytes from the systemic circulation migrate to the labyrinth during an immune response in the inner ear. The aim of this study was to prove the capacity of sensitized lymphocytes to transfer autoimmune inner ear disease, and to describe the resulting morphological and physiological changes. Therefore two groups of sensitized lymphocytes partially labelled with a radioactive marker from inbred guinea pigs with an immune response within the inner ear were injected into the bloodstream of naive recipient animals. Most of the labelled cells were observed in the apical turn of the experimental cochlea, while only few cells were detectable in the control cochleas. In addition, the absence of otoacoustic emissions and the loss of outer hair cells observed by electron microscopy were interpreted as a sign of damage caused by the provoked immunopathologic mechanism. The results are discussed as a possible model for a sympathetic cochleolabyrinthitis.

Animals↗
PubMed1995

Inherited hearing defects in mice.

Mouse mutants with hearing impairment are useful for elucidating the pathological processes underlying auditory system defects, as well as for understanding the normal process of auditory development and sensory transduction. Deaf mouse mutants are also valuable for identifying the responsible genes by positional cloning, and are used to expedite the search for genes involved in human deafness. The distribution of candidate genes for deafness across the mouse genome is presented, together with a summary of the key features of the mutants involved. Genetic defects affecting hearing can be grouped into broad categories according to their pathological features. These categories include middle ear defects, morphogenetic inner ear defects, central auditory system defects, peripheral neural defects, neuroepithelial defects, cochleo-saccular defects, and late onset hearing loss. The biological features and molecular basis of each type of hearing impairment are described. Finally, the effects of mutations in orthologous genes involved in the auditory system in humans and mice are compared.

Animals↗
PubMed1998

3D MRI of the membranous labyrinth. An age related comparison of MR findings in patients with labyrinthine fibrosis and in persons without inner ear symptoms.

PURPOSE: We compared MRI of the membranous labyrinth in patients with chronic non-neoplastic inner ear disease and MR signs of labyrinthine fibrosis and controls depending on their age, in order to establish whether there were any MR differences regarding patient age groups, control age groups and between the patients and controls themselves. MATERIALS AND METHODS: Clinical ENT examinations as well as a T2* weighted 3D CISS (Constructive Interference in Steady State) sequence with a slice thickness of 0.7 mm were performed. Our collective was subdivided as follows: 0-19 years (10 controls, 3 patients with chronic non-neoplastic inner ear disease), 20-49 years (55 controls, 8 patients), 50 years and older (40 controls, 22 patients). Detectability of labyrinthine structures (e.g. cochlea, vestibule, semicircular canals) and filling defects were evaluated. RESULTS: In the 3 age-groups of the control collective no significant differences were observed in the membranous labyrinth. However differences concerning labyrinthine detectability emerged between controls and patients in both the 20-49 years and 50 years and older age groups. In the patient collective the 3 age groups showed no significant discrepancy in the mean number of lesions. CONCLUSION: Filling defects of the membranous labyrinth on 3D CISS MR images are pathological even in older persons. We would therefore recommend high resolution T2* weighted MRI in the case of suspected labyrinthine fibrosis.

Adolescent↗