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At least 73 records · Page 4Linked to original sources
PubMed1990

[Gherini-Causse endo otoprobe and HGM argon laser. Value in the surgery of ear abnormalities].

Performing a stapedectomy in a slightly fixed otosclerotic footplate may induce an excessive motion of the labyrinthine fluids, damaging inner ear membranes and Corti hair cells fragilized by proteolytic enzymes. The fluid motion in the cochlear canal is quantic size only. The replacement of a slightly fixed footplate by an ideal compliance and impedance transmitting device, may allow the surgeon to get a tremendous improvement of hearing (as a Meniere disease). The Gherini-Causse multi-use endo-otoprobe combined with a HGM Argon Laser, if associated with a Skeeter Oto-tool drill, looks to be an efficient and safe solution to this otologic surgical challenge.

Argon↗
PubMed1990

[Effects of body posture on cochlear performance].

Experimental research has demonstrated that changes in body position influence auditory function and, specifically, supine position produces a sensorineural hearing loss at low frequencies. The hypotheses to interpret these phenomena are principally referred to an increase of hydrostatic pressure of labyrinthine fluids. In order to evaluate the effects of head position on the cochlear performance a modern test battery has been performed to study cochlear function in 11 normal subjects ranged in age from 22 to 34 years. The tests (Remote Masking:RM; Brief Tone Audiometry:BTA; Critical Ratio:RC) have been evaluated in two positions: sitting upright and supine with the head at a 20 backward angle. The results of our research have shown that in all the cases, the supine position produces a significant shift of the auditory threshold at 250 and 500 Hz, and a decrease of RM values in about all of the cases. We have estimated non statistically significant differences for the RC and BTA values, in more than half of the ears tested. On the basis of the significance given to RM, BTA, RC: we can deduce that the modifications of the auditory performance related to an increase in perilymphatic hydrostatic pressure, induced by the head position are produced by an increase in rigidity of the mechanical vibratory structures of the cochlea rather than the expression of sensorineural damage.

Adult↗
PubMed1989

[Clinical aspects of sudden deafness and vestibulopathy].

Clinical aspects of sudden deafness and sudden vestibular loss. The cases of sudden deafness and/or sudden vestibular loss are 90% idiopathic. Initially they can be overlooked but they can be responsible for an important sensorial impairment. In 65% of cases, and within the first two weeks, there may be a relevant or complete recovery or functional compensation. Etiology and pathogenesis are considered to be pluri-factorial; multiple virus infection including the Herpesvirus family, is the most relevant and better documented cause. Such an infection is responsible for a derangement of inner ear microcirculation, ions imbalance at labyrinthine fluids level, reduction of receptors and nervous supply function. Therapy is essentially symptomatic and therefore the most widely used drugs are cortisonics and heparin. In the Author's opinion also dextran 40, by slow endovenous drip, and carbogen (O2 95% + CO2 5%), by inhalations, are very effective with only rare contraindications. The occurrence of an important number of spontaneous improvements or even recoveries does not authorize therapeutic abstension especially in severe or delayed cases.

Hearing Loss, Sudden↗
PubMedDate not supplied

Cochlear and otoconial abnormalities in capsular otosclerosis with hydrops.

Temporal bones from four patients with capsular otosclerosis were examined by microdissection. Otoconia and abnormal crystalline deposits were studied by scanning electron microscopy and x-ray analytical methods. One patient showed more or less symmetrical invasion of the basilar membrane and osseous lamina by connective tissue from thickened endosteum adjacent to the larger anterior foci. In one ear sensorineural degeneration was circumscribed; in the other it was extensive and associated with cochleosaccular hydrops. Two other patients were deaf, with severe sensorineural degeneration; one had multiple active foci and evidence of cochleosaccular hydrops. In the fourth patient, who had small anterior foci, no specific inner ear pathology was found related to otosclerosis. In the hydropic labyrinths, apatite was present as abnormal deposits in the cochlear duct and as rigid crusts replacing the otoconia. Apparently these changes had been associated with abnormal labyrinthine fluid dynamics rather than with the otospongiotic process per se.

Aged↗
PubMed1993

Betahistine-induced vascular effects in the rat cochlea.

Betahistine (BH) has been used widely to treat cochlear disorders, such as tinnitus and Meniere's disease. The mechanism of action of BH in the cochlea is assumed to be based on its histamine-like effect on H1 receptors in the cochlear vasculature, leading to an increased cochlear blood flow (CBF). Recently it has been shown that BH can strongly affect H3 heteroreceptors (a novel histamine receptor subclass) in the periphery, via an autonomic ligand. This mechanism may also contribute to the BH effects on CBF. This study was to validate BH effects in the cochlear vasculature and to investigate the possible mechanisms of action of this drug in the inner ear vasculature. We assessed the effects of BH on CBF with the laser Doppler flowmeter in 23 rats and concluded that BH affects vascular conductivity in the cochlea in a dose-dependent fashion; betahistine diffuses through the round window, but does not have access to vascular receptors or ligands once in the labyrinthine fluids; and the H1 receptors mediate the systemic and peripheral vascular effects of BH, whereas the cochlear effect involves cholinergic receptors.

Animals↗
PubMedDate not supplied

Pathology of the membranous labyrinth: comparison of T1- and T2-weighted and gadolinium-enhanced spin-echo and 3DFT-CISS imaging.

PURPOSE: To assess the value of unenhanced T1-weighted images, T2-weighted images, gadolinium-enhanced T1-weighted images, and three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) images in depicting lesions of the membranous labyrinth. METHODS: Six patients were studied using 1-T MR; both enhanced (gadolinium-tetraazacyclododecane tetraacetic acid) and unenhanced images were obtained and different sequences compared to determine which provided the most information. RESULTS: A combination of gadolinium-enhanced T1-weighted and 3DFT-CISS images could depict all membranous labyrinth pathology. Unenhanced T1-weighted images were necessary to exclude spontaneous hyperintensity in the membranous labyrinth. Gadolinium-enhanced T1-weighted images were needed to detect enhancing pathology such as labyrinthitis and tumors inside the membranous labyrinth. In these cases, 3DFT-CISS images allowed immediate differentiation between inflammation and tumor. In temporal bone tumors involving the bony and membranous labyrinth, unenhanced and enhanced T1-weighted images often sufficed to suggest the correct diagnosis. Only 3DFT-CISS images were able to demonstrate small structures (as fistulas) and to help us confirm or rule out obliteration of the labyrinthine fluid spaces. 3DFT-CISS images were necessary to detect small congenital malformations of the membranous labyrinth when only MR was performed. Uncalcified obliteration of the labyrinth fluid spaces could be reliably detected only on 3DFT-CISS images. Here also gadolinium-enhanced T1-weighted images had to be obtained because enhancement of the soft tissues inside the membranous labyrinth had been observed. CONCLUSION: The CISS sequence and enhanced T1-weighted sequence formed the best sequence combination for diagnosis of membranous labyrinth lesions; additional, unenhanced T1-weighted images can help one differentiate labyrinthitis, proteinaceous fluid, subacute hemorrhage, or tumor inside the labyrinth.

Adolescent↗
PubMed1996

[Positional impedance tests with acetazolamide: a clinical test for evaluating endolymphatic hydrops].

The authors report on the possible advantages acetazolamide, in conjunction with Positional Impedenzometry, can provide in the detection of minor labyrinthine hydrops and major labyrinthine fluid tension disorders. This study was carried out using the case/control method. The subjects were selected on the basis of symptoms and clinical examination revealing signs of endolymphatic hydrops. Tonal audiometry and positional impedenzometry according to Marullo were performed both before (pre-test) and after i.v. administration of 500 mg sodium acetazolamide (post-ACZ1 and post-ACZ2). Audiometry showed that in 77.2% of the cases there was a significant variation in threshold. In positional impedenzometry the average post-ACZ1 (delta PISC went from 22.06% (pre-test) to 13.16% and the post-ACZ2 (delta PISC went to 23.15%). On the other hand no significant changes were seen in the controls. Some hypotheses are offered on the mechanisms giving rise to these effects and particular attention is focused on the effect acetazolamide has on the carbon dioxide in the endolymphatic sac. In conclusion the authors consider the advantages this method offers over the "classical" tests used in diagnosing Ménière's Disease and minor hydrops.

Acetazolamide↗
PubMed1996

[Wegener granulomatosis: a clinical case with parossistic positional vertigo due to involvement of the lateral semicircular canal].

The ear is involved in more than 20% of all cases of Wegener Granulomatosis (W.G.): such involvement takes place either through direct proliferation of the necrotic-granulomatosis tissue in the middle ear, or is a consequence of perieustachian tube infiltration from the rhinopharnyx. The inner ear is affected later and it is not clear as to exactly how. The present paper deals with the case of a 63-year-old woman who had a year been suffering from bilateral ear pain, and persistent otorrhea with typical signs of purulent chronic middle-ear otitis. During the course of the illness the patient complained of atypical paroxymal positional vertigo, compatible with cupulolithiasis of the semi-circular horizontal canal (as per E.N.G. recording). Transoral biopsy of the rhinopharynx and of the left nasal fossa revealed histopathological signs compatible with W.G.. In the light of post-mortem temporal bone studies performed by Friemann and Blatt on W.G. patients the present case could lead to further studies regarding the advancement of this pathological process within the middle and inner ears and the etiopathogenetic mechanisms involved. In particular, during the course of W.G., the appearance of benign paroxymal positional vertigo through cupulolithiasis of the semicircular horizontal canal may be justified: a) by the progressive involvement of the posterior labyrinth structures affecting the semicircular canals prior to the lateral canal and running on to the posterior canal; b) by the discovery of proteiform material in the labyrinthine fluids.

Cerebrospinal Fluid Otorrhea↗
PubMed1979

Effect of urea on osmolality of perilymph.

Blood osmolality was altered in chinchillas by intravenous administration of urea. Serum osmolality peaked rapidly at 30 minutes after administration and decreased slightly to a plateau for 180 minutes. Perilymph and CSF osmolality lagged substantially behind the increase in serum osmolality and equaled serum osmolality only after one hour. Perilymph osmolality followed changes in the serum up to 60 minutes with a definite time lag. This phenomenon suggests the existence of a selective blood-labyrinth barrier that is permeable to urea and water. However, the time lag due to the barrier may permit the reduction of hydrostatic pressure in the labyrinth. The results of the present study seem to render partial explanation of improved hearing in patients with Meniere's disease who were treated with urea.

Animals↗
PubMed1982

[Microflame-photometric estimation of sodium and potassium for testing the purity of inner ear fluids (author's transl)].

A simple micromodification of simultaneous flame-photometric estimation of sodium and potassium concentration in sample volumes of 0.1 microliter is described for testing the purity of inner ear fluids, especially of perilymph. The precision of the method is about 10% (calibration standards, Table 2) and depends mainly on the precision of measuring the small sample volumes. The method has been used for examining cerebrospinal fluid, perilymph, and endolymph samples of guinea pigs. The increased perilymphatic potassium (Fig. 1a) and endolymphatic sodium values suggest a more or less substantial contamination of the tested samples and underline the necessity of checking the purity of inner ear fluid samples which are used in biochemical analysis.

Animals↗
PubMedDate not supplied

Perilymphatic pressure in the cat. Description of a new method for study of inner ear hydrodynamics.

Continuous recordings of the perilymphatic (Pp), cerebrospinal fluid (PCSF), central venous (PCV) and arterial (PA) pressures have been performed on anesthetized cats. The perilymphatic space was reached by an extraural approach that leaves the ear canal and middle ear intact. A conical canal was drilled into the temporal bone down to the vestibule. The position of the canal was later confirmed histologically. A small, threaded, metallic cannula was screwed into the bone. For pressure measurements Millar microtip transducers were used, thus giving minimum measurement volume displacement. The mean PP and PCSF were found to be equal, whereas the maximum pressure during expiration was significantly higher in the CSF. not affected by the given anesthetics. Ligation of the external jugular veins had a minor and temporary effect on the PP and PCSF. The method is considered to be suitable for studies on the inner ear hydrodynamics as well as for audiophysiological measurements with an intact middle ear transmission system.

Animals↗
PubMed1989

Effects of posture and age on tympanic membrane displacement measurements.

This study used changes in posture to investigate the transmission of cerebro-spinal fluid (CSF) pressure changes to the cochlear fluids in subjects falling into two age groups. Results were obtained from 32 subjects: 16 aged 19 to 32 years and 16 aged between 40 and 63. Measurements were made with the subject sitting upright and then at 63 degrees to the vertical, using a technique which measures displacement of the tympanic membrane in response to acoustic stimulation of the stapedial reflex. Changes in such measurements are believed to represent changes in perilymphatic fluid pressure. Statistical analysis of the results showed the magnitude of changes in Tympanic Membrane Displacement (TMD) measurements with postural change to be smaller in the older group than in the younger age group. In addition, a larger proportion of the older subjects showed no change in TMD measurements with change in posture. The proportion of subjects in each age group who showed no change in TMD measurements with change in posture was similar to the proportion of temporal bones of subjects of similar ages that had non-patent cochlear aqueducts as determined by a previous histopathological study. Audiometric testing revealed a link between hearing threshold and presumed patency of the communication routes between cochlear and cranial fluids. The magnitude of the tympanic membrane displacement was found to decrease with age in agreement with previous studies showing decrease of stapedial reflex magnitude with increasing age. It is suggested that the communication between cochlear and cranial fluids may be important in the pathogenesis of auditory dysfunction in several patient groups.

Adult↗