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Results for “Vestibular Function Tests”

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PubMedDate not supplied

The effects of noise on the vestibular system.

PURPOSE: Subjects with noise-induced hearing loss sometimes also complain about balance disorders, but reports of clinical series that give contradictory results are highly controversial. This study was designed to evaluate the effects of intense noise on the vestibular labyrinth, both in subjects with symmetrical hearing loss and in subjects with asymmetrical loss, and to examine the correlation between the subjects' complaints and the results of the vestibular function tests. METHODS: A total of 258 male military personnel, heavily exposed to various intense noises, were included in the study. They were divided into 2 groups according to their hearing; 134 had a symmetrical high-tone hearing loss, and 124 had asymmetrical losses. Each group was divided into 2 subgroups according to the presence or absence of vestibular complaints. All of the subjects underwent a complete audiological and electronystagmographic evaluation. RESULTS: We found that vestibular damage caused by intense noise exposure might be expressed clinically in subjects with asymmetrical hearing loss. There was a strong correlation between the subjects' complaints and the results of the vestibular function tests. There was no correlation between the severity of the hearing loss and the vestibular symptomatology and pathology. CONCLUSIONS: Subjects exposed to intense noise may have evidence of vestibular pathology only when there is an asymmetrical hearing loss. Whenever hearing loss is symmetrical, an equal damage to the vestibular system of both ears is most probably responsible for the absence of abnormal findings on the vestibular function tests. The results of this study have important medicolegal implications for individuals exposed to intense noises.

Adult↗
PubMed1973

The significance of optic fixation in tests of vestibular function.

Claims are often made that the electronystagmographic recording of induced nystagmic responses either with eye closure or in darkness enhances the sensitivity of the test. While this may be true of certain parameters it is not true of all and may in fact lead to a reduction in the diagnostic information obtainable with optic fixation upon a target.

Caloric Tests↗
PubMed2005

[Exploration of the otolith function].

The analysis of our vertiginous patients reveals that the likely existence of a pattern of symptoms related to a disturbance of the otolith organ responsible for detection of linear accelerations. Very often otolith pathology affects only certain directions of movement or tilting in relation to gravity. The various tests of the otolith function do not seem to identify all of these otolith deficits. It is possible that each individual test explores only partially the 4 otolith organs. Our otolith tests are still either too general, or, only focused on a part of a multi-directional function (and wrongly emphasizing a partial pathology). Thus, the history remains the finest diagnostic tool. The exploration of the otolith function has improved. These tests are not redundant. The subjective visual vertical tests the otolith function up to the vestibular cortex whilst the off-vertical axis rotation (OVAR) test explores the ocular otolith reflex. The myogenic otolith evoked potentials are saccule-collic. The cerebral cartography shows the various zones of cortical saccular activity and the tilt suppression test explores a reflex involving the cerebellar nodulus. However all of these tests are still nonspecific. There 'non-specificity' is similar to the non-specific nature of a free field hearing or the rotatory vestibular tests. The analysis of patient symptoms, using diagrams summarizing the principal clinical findings, or using a 3D software, facilitates the identification of the involved side, the affected organ (utricle or saccule) and to some extent the possible site of the lesion (just as a visual field would assist in identification of the retinal area affected prior to fundoscopy). Some otolith tests can be very sensitive albeit non-specific like the subjective visual vertical test. Others are more specific in identification of the organ and side affected like the otolith sacculo-collic evoked potentials. The choice of vestibular function tests is best based on the patient's particular symptoms. Thus a patient complaining of falling outwards is to be tested by offset rotations. A patient complaining of falling while going down in a lift is best investigated by the cortical vestibular otolith evoked potentials.

Humans↗
PubMed2001

Vestibular histopathology of the human temporal bone. What can we learn?

Histologic sections of the human temporal bone display snapshots of the entire lifetime integrated into the moment the bone enters fixative. The bulk of the literature on vestibular histopathology is anecdotal and descriptive in nature, rather than quantitative. This is because the means of describing and measuring patients' vestibular symptoms are poorly developed, and the complex geometry of the vestibular labyrinth complicates efforts to study it in serial histologic sections. Histopathologic findings in the common peripheral vestibulopathies, including Meniere's syndrome, benign paroxysmal positional vertigo, viral labyrinthitis, vestibular neuronitis, and ototoxicity, have all been described. A new quantitative method for assessment of vestibular otopathology using Nomarski optics has recently been reported. It has been successfully applied to create a normative database of age-related changes in the vestibular hair cell populations which, in turn, has been used to study the effects of aminoglycoside ototoxicity and Meniere's syndrome. These data provide the first meaningful opportunity to make structure-function correlations between vestibular function testing and temporal bone pathology in humans. Wider clinical application of vestibular function testing and postmortem temporal bone donation should be promoted by all investigators interested in accumulating the resources necessary to gain a deeper understanding of the human vestibular system in health and disease.

Aged↗
PubMed2000

Testing the central vestibular functions: a clinical survey.

In vestibular examinations anomalies in the saccade and smooth pursuit tests as well as the fixation suppression after caloric stimulation might indicate central lesions in the vestibular system. Additionally, a high gain in the torsion test is suspicious of cerebellar dysfunction. In this study, 141 patients out of 973 had at least one of these anomalies. For 125 patients we were able to compare the initial findings in the vestibular examination with the final diagnosis by otologists, neurologists and general practitioners. The complaints of 37.6% of the patients with these electronystagmographic (ENG) anomalies appeared to be of central origin. Abnormal saccades, an abnormal smooth pursuit, and an elevated gain in the torsion test were not independently diagnostic for central vestibular disease. The fixation suppression index appeared to be lower for subjects with peripheral vestibular disease. Otologists more often referred their patients to a neurologist if the fixation index was elevated.

Adolescent↗
PubMed2001

Decreasing hair cell counts in aging humans.

Deterioration of balance with advancing age is a well-known fact of life. Some investigators have reported a 50% prevalence of dizziness in the elderly. Clinically, progressive dysequilibrium of aging presents as gradually worsening balance due to age-related decline in function of the peripheral vestibular system, central nervous system, vision, and musculoskeletal system. Vestibular function testing has shown clear evidence of age-related changes in peripheral and central sites. Histopathologic changes in the vestibular sensory organs include progressive hair cell degeneration, otoconial degeneration in the otolith organs, and decreasing number of Scarpa's ganglion neurons. Recently, a new quantitative method of assessing vestibular otopathology has been described, utilizing Nomarski differential interference contrast microscopy. This technique has been applied to 67 human temporal bones of individuals from birth to age 100 to create a normative database of total, type I, and type II hair cell counts as a function of age. Results show a highly significant continuous decrease in all counts from birth to age 100, best fit by a linear regression model. Type I hair cell counts in all three semicircular canal cristae decrease at a similar rate, significantly faster than the degeneration observed in type I hair cells of the maculae. Type II hair cell counts decline at the same rate for all 5 sensory epithelia. These normative data provide the basis for comparisons to hair cell counts made in temporal bones from subjects with known vestibular disorders. They also provide a basis for drawing correlations between vestibular function testing and vestibular otopathology.

Aged↗
PubMed2005

[Kinetic tests representativity in vestibular function].

INTRODUCTION: The most frecuently tests used to study the vestibular system, with videonystagmographic register, are the caloric and rotatory ones. MATERIAL AND METHODS: We have carried out a comparative study of the kinetic tests through a sample of 41 patients without vestibular pathology, stratified by age and gender. The performed rotational tests have been: Constant/cycles, postrrotatory test, increasing, decreasing and constant test. RESULTS: We have not observed age or gender influence on the results. We give the numeric results of these tests. CONCLUSION: The obtained data allow to conclude that the information given by the increasing and decreasing pendulous test is similar, phenomenon that doesn't happen in the rest of the practiced tests. We also study the habituation phenomenon to a know stimuli. We point out the importance of each laboratory to have their tests done previously in a normal control group in order to compare the results when performing them in pathological patients.

Adult↗
PubMed2004

Garnett Passe and Rodney Williams Memorial Lecture: New clinical tests of unilateral vestibular dysfunction.

Vertigo is caused by unilateral vestibular dysfunction. Unilateral vestibular dysfunction represents either vestibular overactivity as benign positional vertigo or underactivity as in labyrinthitis or both, at different times, as in a Ménière's attack. Unilateral dysfunction could also be central rather than peripheral, such as in a lateral medullary syndrome. Unilateral vestibular dysfunction could affect any of the five different sensory areas in the labyrinth, the three semicircular canals and the two otoliths, or their brainstem connections. For rigorous diagnosis of the cause of vertigo, ideally one would have robust, reproducible, quantitative vestibular function tests sensitive to dysfunction of each of the five sensory regions in each ear. In working towards this ideal we have, over the last 15 years, developed three new vestibular function tests: (1) impulsive tests of individual semicircular canal function, (2) evoked potential tests of saccular function and (3) subjective visual horizontal tests of utricular function. The physiological rationale of these three tests is reviewed as well as the interpretation of their results in various diseases.

Evoked Potentials, Auditory↗
PubMed1981

Human vestibular epithelia: prospects for future study.

The lateral ampullae of thirteen patients, removed during translabyrinthine surgery for various disorders, have been examined with light and electron microscopy. Correlation of results of vestibular function tests with changes of histology and ultrastructure have been attempted. Light and electron microscopy revealed the same features that other investigators have reported as pathologic changes in the sensory epithelium and associated subepithelial structures. The occurrence of these features did not correlate with the vestibular function tests, indicating that these features, in our tissue samples, were handling and preparation artifacts. Two observations made in a specimen from a patient with Meniere's disease were difficult to ascribe to handling or preparation artifact. One was the presence of densely stained granular inclusions in the basal portion of the sensory epithelium. The location and contents of these inclusions as seen in the electron microscopy indicated they were hypertrophied degenerating nerve terminals. Similar inclusions were also seen in the axoplasm of myelinated nerve fibers in the sensory subepithelial connective tissue. The other observation believed to be relevant to the symptoms of Meniere's disease, was the presence of widened tight junctions between adjoining sensory and supporting epithelial cells. The attempt at correlation of histologic and ultrastructural changes of ampullae with vestibular function has made possible some differentiation between pathology and artifact. The significance of the ultrastructural observations is discussed.

Adult↗
PubMed1994

Swimming test for evaluating vestibular function in guinea pigs.

A swimming test was used to evaluate vestibular function in guinea pigs. We first observed tracings of the swimming patterns of 20 healthy guinea pigs to establish the normal range. Then the same test was used in a group of 49 guinea pigs with endolymphatic hydrops induced by immunologic techniques. They did not show spontaneous nystagmus or body deviation while walking, but a total of 20 out of 49 animals displayed abnormal swimming patterns, with 8 swimming clockwise and 4 counterclockwise. This swimming test is easily able to detect mild vestibular dysfunction in guinea pigs, and can be repeated, so that we consider it useful for examining vestibular function in these animals.

Animals↗
PubMed1993

Neurotologic manifestations of Chiari 1 malformation.

It is important for otolaryngologists to recognize Chiari malformations as part of the differential diagnosis of balance disorders because patients may initially be seen with symptoms referable to the vestibular system, including ataxia, nystagmus, or vertigo. The objective of this paper is to review the signs, symptoms, and vestibular test findings of a series of patients with Chiari 1 malformation. Six patients were identified by retrospective chart review with a diagnosis of Chiari malformation. Each patient had a complete otoneurologic examination and vestibular function testing. The results indicated that patients fell into two different vestibular test result profiles. First, patients with advanced symptoms demonstrated oculomotor dysfunction, central vestibular nystagmus, abnormal vestibular visual interaction, and abnormal tilt suppression of postrotatory nystagmus. On the other hand, a number of patients were identified with incidentally noted Chiari malformation on magnetic resonance imaging scan who had a vestibular test profile consistent with peripheral vestibulopathy without signs and symptoms of central nervous system dysfunction. Guidelines are provided to help determine the extent of the group of symptoms attributable to an incidentally discovered Chiari malformation.

Adolescent↗