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At least 217 records · Page 12Linked to original sources

PubMed2004

Dizziness.

BACKGROUND: The article gives an overview of the most frequent forms of vertigo, that are of peripheral-labyrinthine, central-vestibular, psychogenic, or physiologic origin. Dizziness or vertigo is a result of a mismatch between 3 sensory systems: the vestibular, the visual, and the somatosensory systems. These systems are mutually interactive and redundant in that orientation and balance are guided by simultaneous reafferent cues. The functional ranges of the systems overlap, thus permitting them to compensate in part for each other's deficiencies. SUMMARY: Vertigo is not a well-defined disease entity, but rather a multisensory syndrome induced either by stimulation of the intact sensorimotor system by motion (eg, physiologic vertigo as in motion sickness or height vertigo), or by pathologic dysfunction of any of the stabilizing sensory systems (eg, peripheral vestibular as in vestibular neuritis, or central vestibular as in vertebro-basilar ischemia). The core region in vestibular vertigo syndromes is the vestibulo-ocular reflex, a 3-neuron arc that mediates the information of the semicircular canals and otoliths via the vestibular nerve and vestibular nucleus to the ocular motor nuclei (VI, IV, III) and the supranuclear integration centers in the ponto-mesencephalic brain stem. CONCLUSIONS: Clinical phenomena characteristic for physiological and pathologic vertigo syndromes include postural, perceptual, oculomotor, and vegetative syndromes, which manifest with ataxia, nystagmus, vertigo, and nausea. Thus, the clinical testing must include examinations of postural, perceptual, oculomotor, and vegetative dysfunctions.

Ataxia↗

PubMed1982

The Mondini defect in Turner's syndrome. A temporal bone report.

The histopathology of the right temporal bone of a 47 year old deaf woman with Turner's Syndrome (gonadal dysgenesis) is described. The appearances are of the Mondini deformity, the cochlea consisting of a single basal turn with a bulbous apical dilatation. The organ of Corti was absent. The remainder of the bony labyrinth save for the cochlear aqueduct was normal. The patient's death was due to a cerebral astrocytoma. Previous reports concerning the co-existence of gonadal dysgenesis, congenital deafness and non-gonadal neoplasia are discussed.

Astrocytoma↗

PubMed1995

Inner ear barotrauma: computed tomographic evaluation.

Eight patients with inner ear barotrauma were evaluated by computed tomography. The causes of the inner ear barotrauma were diving in four, flying in an airplane in three, and climbing in one. Regarding the width of the cochlear aqueduct, no significant difference was observed between the affected side (3.28 +/- 0.49 mm) and non-affected side (3.63 +/- 0.79 mm) at the base of the infundibulum. The jugular fossa could not be identified on the affected side in three patients. Some relationship may exist between inner ear barotrauma and poor development of the jugular fossa.

Adult↗

PubMed1984

Fenestral otosclerosis: significance of preoperative CT evaluation.

Thirty-five consecutive patients with the clinical diagnosis of fenestral otosclerosis were evaluated with high-resolution computed tomography (CT). Twenty-six were diagnosed as having this disorder by CT evidence of abnormal bony excrescences at or adjacent to the oval window. The diagnosis was made upon examination of 1.5-mm-thick targeted sections obtained at 0.5-mm intervals in the axial projection. Coronal sections were also included. Sections were also evaluated for evidence of plaque formation elsewhere in the lateral wall of the labyrinth and for surgical obstacles such as an abnormally wide cochlear aqueduct, a high jugular vein, and a dehiscent facial nerve. It is concluded that fenestral otosclerosis may be accurately diagnosed with proper CT techniques.

Adult↗

PubMed1976

Labyrinthine anomalies in trisomy 13 mosaicism.

The temporal bone histopathology of a 2-month-old male with a bilateral cleft palate, cleft lip and polydactylia due to trisomy 13 mosaicism was studied. Anomalies in the ear involved a partial absence of the superior semicircular canal, an abnormally wide lateral semicircular canal, underdeveloped cochlear coils, an abnormally broad modiolus, an undeveloped organ of Corti and an underdeveloped basilar membrane in the basal turn of the cochlea, an unusually wide cochlear aqueduct, and deformed stapedial crura.

Adult↗

PubMed1976

Quantitative assessment of perilymph sources.

The problem of the perilymph origin--influx of cerebrospinal fluid (CSF) versus ultrafiltration within the cochlea--cannot be solved by mere qualitative proofs of tracer passage through the cochlear aqueduct. In order to gain quantitative data on the possible perilymph sources, an experimental study was designed to follow the time course of dye concentrations in the cisternal CSF and in the perilymph after tracer injection into the CSF at the vertex. By comparing the resulting concentration peaks in both fluids, the mean peak of the perilymph tracer concentrations was found to reach 36% of the maximum CSF concentration only. It is concluded that the local perilymph production within the cochlea exceeds the influx of CSF by a ratio of about 2:1. A working hypothesis of the double perilymph origin is discussed.

Animals↗

PubMed2002

Spontaneous intracranial hypotension: a rare cause of labyrinthine hydrops.

Spontaneous intracranial hypotension should be considered as a possible cause of cochlear hydrops. We report a case of unilateral hearing loss attributed to spontaneous intracranial hypotension on the basis of characteristic abnormalities seen on magnetic resonance imaging. The diagnostic gold standards for intracranial hypotension are lumbar measurement of cerebrospinal fluid pressure and magnetic resonance imaging. The usual treatment is an autologous blood injection into the peridural spaces. The mechanism of hearing loss is thought to involve secondary perilymph depression due to a patent cochlear aqueduct. This perilymph depression would induce a compensatory expansion of the endolymphatic compartment, with a subsequent decrease in basilar or Reissner's membrane compliance. Endolymphatic hydrops can occur in the course of intracranial hypotension, and not only because of abnormal endolymph production or resorption. Hydrops can thus be classified into 1) syndromes of endolymphatic origin and 2) syndromes of perilymphatic origin, in which loss of perilymph induces compensatory expansion of the endolymphatic space.

Adult↗

PubMedDate not supplied

Rupture of the round window membrane.

A case of sudden deafness due to rupture of the round window membrane is presented. Nineteen similar cases have previously been reported in the literature. In a review of these twenty patients, it is noted that a history of concurrent physical effort or barotrauma was present in eighteen. This supports the view that the injury is produced by pressure changes acting either along the cochlear aqueduct (the explosive route) or, directly on the middle ear structures (the implosive route). At operation, the rupture may be difficult to see, and a separate leak from the oval window may be present. The timing of any surgical intervention is important. The authors recommend that this should be deferred for one week after the onset of symptoms, as the fistula may heal spontaneously. If no definite improvement has occurred at the end of this time, then tympanotomy should be undertaken during the next week.

Adult↗

PubMedDate not supplied

Sudden deafness: histopathologic correlation in temporal bone.

The histopathological study of two cases of sudden deafness is presented. The temporal bones showed cochleosaccular abnormality. The most striking pathological changes were collapse of the organ of Corti, atrophy of the tectorial membrane, atrophy of the stria vascularis, decrease in the number of the cochlear nerves, collapse of the saccular membrane and partial absence of the sensory epithelial layer in the saccular macula. These changes are quite similar in type to those occurring in labyrinthitis of known viral etiology and to those in previously reported cases of sudden deafness which were assumed to be of viral origin. This evidence suggests that a viral infection was the most probable etiology of sudden deafness in these ears. In addition, unusual findings of endolymphatic hydrops limited to the extreme basal end of the cochlear duct were found in Case 1. A patent cochlear aqueduct and circumscribed perilymphatic labyrinthine ossification in the superior seimicircular canal were also observed. With these histopathological findings, the possibility of viral infection via the meninges as well as via the hematogenous route into the inner ear is proposed.

Cochlea↗

PubMedDate not supplied

Sudden or fluctuating hearing loss and vertigo in children due to perilymph fistula.

Five cases are presented of children with rapid onset of sensorineural hearing loss, disequilibrium, or both, who were found at exploratory tympanotomy to have a perilymph fistula. Four of the children had histories suggesting that antecedent barotrauma or physical exertion contributed to the development of the fistula. One child with congenital unilateral craniosynostosis had a residual temporal bone abnormality on the same side as the perilymph fistula. Two children had identifiable anatomic abnormalities in the middle ear. A classification of perilymph fistula is proposed that describes a congenital, an acquired, and a combined type of fistula. Inner ear fluid dynamics and patency of the cochlear aqueduct appear to be important factors in pathogenesis. Children with unexplained fluctuating or sudden onset of sensorineural hearing loss, and children with unexplained disequilibrium or vertigo should be suspected of having a perilymph fistula. The history can be singularly important in raising the suspicion that a perilymph fistula may be present. Although audiometric, vestibular, and radiographic studies can be helpful, there is no way to prove the presence or absence of a fistula without directly viewing the middle ear. Tympanotomy with repair of the fistula does not assure improvement in hearing.

Adolescent↗

PubMedDate not supplied

Congenital anomalies of the inner ear.

This study investigated congenital anomalies occurring in the inner ear, with particular attention to their features, localizations, and frequencies. Seventy-seven human temporal bones obtained from 53 individuals, aged one day to 39 years, each of whom had anomalies of the external ear, middle ear, and/or inner ear, were used for this study. The temporal bones had been removed at autopsy, fixed, dehydrated, embedded in celloidin, and sectioned horizontally or vertically at 20 microns. Every tenth horizontal section or every 20th vertical section was stained with hematoxylin and eosin, mounted, and studied under a light microscope. There were 206 inner ear anomalies (117 in the vestibular system, 79 in the cochlea, 10 in the internal auditory meatus) in the 51 bones studied. Fifty-four different features of anomalies were present at 33 different locations in the inner ear. The most frequent anomalies observed were shortened cochlea (23 bones), enlarged vestibule (17 bones), wide cochlear aqueduct (16 bones), absence of lateral semicircular canal (14 bones), and large osseous lateral semicircular canal (10 bones). The most common site of inner ear anomalies was thus the lateral semicircular canal, which was involved in 46 of the 206 anomalies observed; the anomalies in this organ were variable in type. The implications of inner ear anomalies are discussed as they relate to fetal development, inner ear dysfunction, and clinical interpretation of polytomographic studies.

Abnormalities, Multiple↗

PubMed1992

Hearing loss as a sequel of lumbar puncture.

Only a few case reports have been published about hearing impairment following lumbar puncture, and not all were thoroughly documented by audiograms. We present nine cases of hearing loss following myelography, lumbar puncture, and spinal anesthesia. We speculate that this rare complication arises only in persons with a wholly or partially patent cochlear aqueduct, and occurs via the release of perilymphatic fluid in the cerebrospinal space. Hearing loss was seen in eight of the nine patients in the lower frequencies, and in six of the nine patients on both sides. Recovery to normal hearing was noticed in six of the nine patients. Transient hearing loss may occur more often than it is generally assumed, and the symptom can remain unnoticed. Since not all of these hearing losses proved to be fully reversible, we suggest informing patients about this complication for medicolegal reasons.

Adult↗

PubMed1994

Changes in cerebrospinal fluid pressure in daily life.

The purpose of the present study was to measure changes in cerebrospinal fluid pressure (CSF-P) during actions of daily life. A spinal tap was performed on 23 inpatients. During the procedure, the patients were requested to perform the following four actions: nose blowing with one side closed, nose blowing with both sides closed, breath holding, and sniffing. The CSF-P was recorded before and during these actions. Of these, nose blowing with both sides closed resulted in the greatest elevation of pressure. Three patients with perilymph fistula showed larger changes than the other 20 patients. Conversely, sniffing lowered the CSF-P in all cases. The present study suggests that daily physical actions cause significant elevations of CSF-P. Such changes may be responsible for the development of perilymph fistula.

Activities of Daily Living↗

PubMed1988

Perilymphatic hypertension.

A syndrome termed perilymphatic hypertension is described as being seen in a small subset of patients with sudden sensorineural hearing loss. A patent or semipatent cochlear aqueduct or modiolus are considered precursors to this condition. Perilymphatic hypertension is believed to predispose to perilymphatic fistula, which may be part of the process of resolution. The pathogenesis for perilymphatic hypertension and fistula are hypothesized and discussed. Treatment for this subset of patients consisted of paracentesis of the round window membrane followed by grafting, with improvement of hearing in certain patients. In no instance did hearing subsequently decrease.

Auditory Threshold↗

PubMed1990

Vestibular effects of chronic perilymph fistula in the cat.

Chronic, unilateral perilymph fistulae were created in cats by removal of the round window membrane and placement of a tympanostomy tube into the round window. Rotary chair, fistula, caloric, and vestibulospinal tests were performed before and after fistulization, and periodically for 2 weeks. At 2 weeks, patency of the fistula was documented by fluorescein injection into the spinal fluid and visualization of leakage into the middle ear bulla via the fistula. All the cats had a patent fistula at 2 weeks, but one of the three cats had a greater perilymph leak than the others. The cat with the more active leak had a spontaneous nystagmus toward the side of the fistula on the first postoperative day; this changed to nystagmus toward the opposite side by the third postoperative day. The other cats had a spontaneous nystagmus toward the opposite side from the first postoperative day. Most abnormal test results returned to normal in the first week after fistulization. Histologic study of the temporal bones revealed that the cat with the greater leak had a wider cochlear aqueduct than the other cats.

Animals↗

PubMedDate not supplied

Investigation of temporal bone anatomy by plastic moulding and cryomicrotomy.

To increase our understanding of the complex topographic relations between temporal bone structures and to facilitate the interpretation of their radiographic images, two techniques were developed. Plastic moulding of temporal bone specimens using polyester resin and silicone rubber substances providing detailed information and a three-dimensional survey of the structures. Carefully macerated temporal bone specimens are filled with plastic material under vacuum and the bone is then dissolved. The preparations, freed from irrelevant structures and embellished, allow metric evaluation of the different structures and their topographic relations. Automatic serial cryomicrotomy of fresh, deep-frozen temporal bones, using a commercial sledge-cryomicrotome. Photography of the cut surfaces of the specimen, usually at distance of 0.25 to 0.50 mm, allows natural-colour reproduction of minute detail, e.g. the melanin cell area in the cochlea, the smallest vessels on the ossicular surfaces, and the origin of the cochlear aqueduct at the basal turn of the cochlea. By correlating the photographs with images from the corresponding tomographic planes accurate information is obtained for interpretation of the radiographic images. A combination of the two techniques facilitates a detailed study and is a valuable aid in the teaching of temporal bone anatomy.

Freezing↗

PubMed1977

Spontaneous and traumatic perilymph fistulas.

Clinicians have been aware of the problem of post-stapedectomy perilymph fistulas for some time. The existence of non-surgical oval and round window fistulas has been known and was first described in detail by Fee in 1968. This paper concerns a small series of patients with spontaneous and traumatic perilymph fistulas. Five oval window fistulas and one round window fistula are reported. Clinical features, audiometric, radiographic and vestibular findings are discussed. The etiology of traumatic and spontaneous fistulas is not well understood, but seems to bear a relationship to sudden increased in intracranial pressure transmitted to the inner ear through the cochlear aqueduct. Middle ear pressure changes, as seen in acoustic or barotrauma, may also cause these leaks. Indications for surgery and techniques of perilymph fistula identification and repair are discussed in the paper. Surgical correction led to relief of vertigo in 80 percent of patients in this series, and significant hearing improvements were seen in 50 percent of the patients. In evaluating patients with sudden sensori-neural hearing loss, or persistent vestibular symptoms following head or ear trauma, the otologist should keep in mind the possibility of a perilymph fistula and actively investigate these patients. Evidence presented in this paper and in the literature suggest that identification and correction of spontaneous and traumatic perilymph fistulas can lead to resolution of vestibular symptoms and improved hearing in a significant number of patients with these lesions.

Adult↗

PubMed1990

Early alterations of cochlear function in experimental perilymph fistulas.

Alterations of cochlear function secondary to perforation of the round window membrane in guinea pigs were expected to reveal sensitive and/or specific audiometric parameters in perilymph fistulas. A perforation of the round window membrane either did not affect acoustic compound action potential thresholds, or induced a delayed, possibly conductive, inner ear hearing loss. Also, evoked suprathreshold responses deteriorated progressively and independently of the increase of compound action potential thresholds. A sudden (conductive) hearing loss and a poor response to suprathreshold stimulation might indicate inner ear damage secondary to a perilymphatic fistula.

Animals↗