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At least 235 records · Page 13Linked to original sources
PubMed1995

Nerve fibres of the endolymphatic sac: electronmicroscopic findings in the Mongolian gerbil.

The presence of separate bundles of nerve fibres in the gerbilline endolymphatic sac (ES) is described, paying particular attention to their ultrastructure and localization. One bundle, localized in the area of the subepithelium which separates the sigmoid sinus from the ES, is composed only of myelinated fascicles which, moreover, seem to have an isolated contact with the ES area. Other two single nerve fibres, much smaller in caliber, are localized in the ES subepithelium and laterally to the ES area, still close to the sigmoid sinus. These fibres, composed of myelinated and unmyelinated fascicles, seem to have a rather longitudinal orientation and, moreover, contract close relationships with the rich vascular network of the ES subepithelial tissue. As far as the course is concerned, the serial sectioning technique would suggest that the nerve fibres get very close to the ES epithelial cell layer, going proximal to distal. Speculations on the origin of this nerve contingent in the ES are proposed and discussed in view of possible new theories for pathogenesis and therapy of some inner ear diseases.

Animals↗
PubMed1992

Electrocochleographic recordings in acute and healed perilymphatic fistula.

In this study, the summating potential (SP) and action potential (AP) amplitude ratio was measured in 15 guinea pigs before and after surgical induction of a round window fistula. The round window fistula was then allowed to heal, and recordings were obtained after 1 month. Stimuli included 8000-Hz and 2000-Hz tone bursts and click stimuli at levels ranging from 100-dB peak equivalent sound pressure level to AP threshold. Immediately after fistula induction, a statistically significant enlargement in the SP/AP amplitude ratio occurred in response to the click and the 8000-Hz tone-burst stimuli. No change in the SP/AP amplitude ratio was observed for the 2000-Hz stimuli. After healing, the SP/AP amplitude ratio generally returned to prelesion values. No unhealed perilymphatic fistulas were observed in any of the 15 guinea pigs at 1 month after fistula induction. Considering the difficulty of diagnosing perilymphatic fistula in humans, it is encouraging to note that, at least in animals, noninvasive electrophysiologic recordings may perhaps be sensitive to the presence of patent perilymphatic fistula.

Action Potentials↗
PubMed1991

Imaging in neuro-otology.

Imaging the disorders of the auditory pathways is best achieved by magnetic resonance imaging (MRI), especially with contrast enhancement. Computerized tomography (CT) still has an important role for disorders of the middle ear as well as congenital, traumatic and other osseous abnormalities of the petrous temporal bone.

Central Nervous System Diseases↗
PubMedDate not supplied

[Otology in diseases of internal medicine interest].

Many clinical manifestations present signs of cochleovestibular impairment. In some cases, otological symptoms are a complication of a disease, while in other cases they are the only early signs and can last for a long period preceding the full development of the primary disease. The otological pathology in the former case is useful for investigating the internal pathology and sometimes for delivering correct diagnosis. On the contrary, in the latter case, it does not offer elements for any etiopathogenic hypothesis because it happens in almost all cases with an acute onset in an otherwise healthy subject and it is always underestimated because of the minor functional impairment. However, clinical studies in the last years led to a significant evolution of otological findings as an early important symptom in the etiopathogenic study and in the diagnosis of some internal diseases. This is true for connectivitis, in which the disease is often preceded by a sudden cochleovestibular symptom, in some dismetabolic or vascular diseases that sometimes begin with fluctuating hearing loss, or in some cochlear manifestations due to ototoxic origin.

Carboplatin↗
PubMed1990

The clinical application of acoustic distortion products.

Otoacoustic emissions provide an objective measure of hair-cell function that is independent of retrocochlear activity. Because of their frequency specificity, distortion-product emissions have great potential for clinical use. The present report describes the results of initial studies in patients with known cochlear or retrocochlear disease, diagnosed with standard otologic and audiologic tests. The cochlear group consisted of those diagnosed with noise-induced hearing loss, Meniere's disease, or hereditary hearing loss, whereas patients with acoustic neuroma comprised a retrocochlear group. A final group consisted of patients with sudden sensorineural hearing loss of unknown origin. Detailed distortion-product emission testing included the computer-controlled acquisition of "audiograms" and response/growth functions. The outcomes of these studies demonstrated that distortion-product emissions provide a noninvasive, frequency-specific test of sensory-cell function that objectively depicts the boundary between normal and abnormal hearing. These emissions were also able to effectively track dynamic changes in progressive disease processes. Finally, as a screening tool, acoustic distortion products provide an objective means of assessing cochlear status in infants and young children and in adults at risk for hearing loss. Because acoustic distortion products accurately measure the sensory component of a sensorineural hearing loss, distortion-product testing may play an important role in the diagnosis and treatment of cochlear dysfunction.

Adolescent↗
PubMedDate not supplied

Electronystagmography in the pathology of the central nervous system.

The program of the electronystagmographic examinations in the pathology of the central nervous system contains 11 groups of tasks. Sixty signs of central impairments are listed, from which 26 nystagmic irregularities had a small diagnostic value. No sign occuring alone could be taken as pathognomonic, only a group of signs can be used for the impairment localization. Besides for the peripheral vestibular and the peripheral vestibulocochlear impairments, the authors succeeded to make a group containing pathogomonic signs for mixed vestibular impairments as well as for multiple sclerosis affecting vestibular structures.

Central Nervous System Diseases↗
PubMed1999

[Clinical course and diagnosis of the acute craniocervical injury].

Combined observation and treatment of 126 patients (80 men, 46 women) aged 15-67 years were carried out in the acute period of craniocerebral trauma of mild or moderate severity. Diagnostic methods including neurological examination, manual testing and X-ray investigation are discussed. The conclusion is made that craniocerebral trauma should be considered as craniocervical trauma as an indirect damage of the neck was revealed in each case in the form of myofascial syndrome pronounced in different degree; cervical syndrome of vertebral artery was also frequent. These data must be taken into consideration in pathogenetic treatment of patients with craniocerebral trauma.

Acute Disease↗
PubMed1999

Steroid-responsive cochlear dysfunction in the MRL/lpr autoimmune mouse.

Corticosteroids historically have been used to treat autoimmune sensorineural hearing loss, although little is known of how steroids restore normal inner ear function. Therefore, to identify a potential model for this field of research, this study examined the effects of prednisolone on auditory brain stem response thresholds in the MRL/lpr mouse model of autoimmune sensorineural hearing loss. Mice treated with prednisolone after auditory threshold elevations demonstrated significant improvement and stabilization of thresholds compared with untreated controls. MRL/lpr mice treated with steroids before the onset of autoimmune disease and cochlear dysfunction demonstrated decreased serum immune complexes, higher survival rates, and lower auditory thresholds compared with untreated controls. These positive results suggest the autoimmune mouse may be useful for studies of steroid-responsive mechanisms of the cochlea in autoimmune sensorineural hearing loss, as well as any hearing disorder in which steroid therapy is currently used.

Animals↗
PubMed1996

Audiometric findings in children with chronic suppurative otitis media without cholesteatoma.

Chronic suppurative otitis media without cholesteatoma (CSOMWC) is usually associated with an increase in air conduction thresholds. However, only a few investigations reported on loss of cochlear function in the pediatric population. We undertook a prospective study in order to further delineate air and bone conduction levels in children with CSOMWC and the possible relationship between sensorineural hearing loss (SNHL) and other clinical characteristics that might reflect the extent of disease. Eighty-seven children were enrolled, 40 of which had bilateral disease. Hence, the total number of diseased ears tested was 127. Audiometric studies were performed three days after achieving a 'dry' ear following medical treatment. We found no statistically significant differences between the bone conduction threshold tested in ears with CSOMWC and control ears. This was also the case in 47 children with unilateral disease when cochlear function was investigated in the diseased and uninvolved ear in the same patient. Clinical correlation showed no association between age, sex, duration of otorrhea and presence of granulation or polyps and the degree of cochlear loss. Our study shows that CSOMWC in children has little effect on cochlear function.

Adolescent↗
PubMed2004

Evaluating patients with vertigo: bedside examination.

Dizziness and vertigo are common complaints in patients referred for neurological evaluation. With a basic understanding of vestibular physiology and proper examination techniques, a correct diagnosis can generally be made at the bedside. This article reviews the most common peripheral and central vestibular syndromes as well as the key elements of the bedside vestibular system examination.

Cerebellar Diseases↗
PubMed1993

Glycerol effect on the guinea pig tectorial membrane.

The tectorial membrane (Tm) of guinea pigs has been found to have an altered organization of its matrix fibers in response to intravenously administered glycerol. Following treatment, the Tm middle zone shows an increase in waviness and clumping of fibers in non-hydropic and several hydropic ears in contrast to non-treated control ears. Residue of the internal sulcus cells occasionally fills the subtectorial space. In the present study, additional investigations were performed with scanning electron microscopy in order to study the relationship between the Tm and the organ of Corti, as well as the relationship between Hensen's stripe and the inner hair cell. Present findings provide evidence for a connection between the inner hair cell stereocilia and Hensen's stripe which may be the molecular basis for the modulation of hearing during the glycerol test in a patient with Meniere's disease.

Animals↗
PubMed2005

Audiologic features of Norrie disease.

OBJECTIVES: Norrie disease is an X-linked recessive disorder in which patients are born blind and develop sensory hearing loss in adolescence. The hearing loss associated with Norrie disease has been shown in a genetically altered knockout mouse to involve dysfunction of the stria vascularis; most other structures are preserved until the later stages of the disease. The objective of this study was to characterize the audiologic phenotype of Norrie disease for comparison with the pathophysiologic mechanism. METHODS: The design combined two series of clinical audiologic evaluations, with special attention to speech intelligibility. RESULTS: The audiologic results for 12 affected individuals and 10 carriers show that patients with Norrie disease retain high speech intelligibility scores even when the threshold loss is severe. CONCLUSIONS: The cochlear mechanism-- failure of the stria vascularis-- accounts for some of the higher values in the wide distribution of speech scores in cases with similar pure tone audiograms.

Adult↗
PubMedDate not supplied

Surgical strategy of cochlear implantation in patients with chronic middle ear disease.

We report 10 postlingually deafened adults in whom the electrophysical criteria for cochlear implant were fulfilled, except that they showed the following unfavorable middle ear lesions: otitis media with effusion, chronic perforative otitis media, cholesteatoma and previous radical ear operation. Staged operations for cochlear implant were performed in 8 cases, and 2 patients who had undergone radical ear operation had a single-stage operation. As a first step, one of the following was performed in each patient as surgically indicated: myringoplasty with or without mastoidectomy, mastoidectomy with reconstruction of the posterior wall of the external canal, mastoidectomy with the insertion of a ventilation tube, radical mastoidectomy or surgical cleansing of the radical cavity. From 6 months to 2.5 years after the first operation, the actual cochlear implant was performed in the second or third stage. There was no major complication as a result of electrode insertion into the cochlea and the results of speech perception in these cases were not different from those in patients with normal middle ears. In our experience, it was considered that the staged operations would enable successful cochlear implants in selected patients with pathological middle ear lesions even if they had previously been diagnosed as contraindicated for this procedure. In a case with radical ear cavity a single-stage operation could be performed when there was no cavity problem.

Adolescent↗