Otolith Function and Disorders
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............................Otolith Function and Disorders
Advances inOto-Rhino-LaryngologyVol. 58
Series Editor W. Arnold, Munich
Otolith Function andDisorders
Volume Editors P. Tran Ba Huy, ParisM. Toupet, Paris
36 figures, 1 in color and 3 tables, 2001
............................Prof. P. Tran Ba Huy,Prof. M. ToupetHopital Lariboisie`re2, rue Ambroise PareF74574 Paris (France)
Library of Congress Cataloging-in-Publication Data
Otolith function and disorders / volume editors, P. Tran Ba Huy, M. Toupet.p.; cm. (Advances in oto-rhino-laryngology, ISSN 0065-3071; vol. 58)
Papers from a conference held in Paris in Jan. 22, 2000.Includes bibliographical references and indexes.ISBN 3805571305 (hard cover : alk. paper)1. Otolith organs Pathophysiology Congresses. 2. Otolith
organs Abnormalities Congresses. 3. Vertigo Congresses. I. Tran, Patrice Ba Huy. II.Toupet, M. (Michel) III. Series.
[DNLM: 1. Otolithic Membrane physiopathology Congresses. 2. OtolithicMembrane abnormalities Congresses. 3. Vertigo Congresses. 4. VestibularDiseases Congresses. WV 255 O88 2001]RF268 .O86 2001617.882dc21
Bibliographic Indices. This publication is listed in bibliographic services, including Current Contents andIndex Medicus.
Drug Dosage. The authors and the publisher have exerted every effort to ensure that drug selection anddosage set forth in this text are in accord with current recommendations and practice at the time of publication.However, in view of ongoing research, changes in government regulations, and the constant flow of informationrelating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug forany change in indications and dosage and for added warnings and precautions. This is particularly importantwhen the recommended agent is a new and/or infrequently employed drug.
All rights reserved. No part of this publication may be translated into other languages, reproduced orutilized in any form or by any means electronic or mechanical, including photocopying, recording, microcopying,or by any information storage and retrieval system, without permission in writing from the publisher.
Copyright 2001 by S. Karger AG, P.O. Box, CH4009 Basel (Switzerland)www.karger.comPrinted in Switzerland on acid-free paper by Reinhardt Druck, BaselISSN 00653071ISBN 3805571305
1 The Mammalian Otolithic Receptors: A Complex Morphological andBiochemical OrganizationSans, A.; Dechesne, C.J.; Dememes, D. (Montpellier)
15 Pathophysiology and Clinical Testing of Otolith DysfunctionGresty, M.A. (London); Lempert, T. (Berlin)
34 Otolithic VertigoBrandt, T. (Munich)
48 Physiopathology of Otolith-Dependent Vertigo. Contribution of the CerebralCortex and Consequences of Cranio-Facial AsymmetriesBerthoz, A. (Paris); Rousie, D. (Lille)
68 Clinical and Instrumental Investigational Otolith FunctionOdkvist, L. (Linkoping)
77 The Subjective Visual VerticalVan Nechel, Ch. (Paris/Bruxelles); Toupet, M. (Paris); Bodson, I. (Paris/Lie`ge)
88 Clinical Application of the Off Vertical Axis Rotation Test (OVAR)Wiener-Vacher, S. (Paris)
98 VEMP Induced by High Level Clicks. A New Test of Saccular Otolith Functionde Waele, C. (Paris)
110 Peripheral Disorders in the Otolith System. A Pathophysiological andClinical OverviewTran Ba Huy, P.; Toupet, M. (Paris)
129 Subject Index
For decades, peripheral vestibular function and its related pathologieshave been attributed to the canal system. In this view, vertigo could only giverotatory sensations. Otherwise, the disorder was automatically considered ascentral in nature. For almost a century, functional explorations were limitedto caloric and/or rotatory testing. From the responses arising from a singlepair of canals, the lateral ones, generations of otologists have founded thescience of Vestibulology.
Yet, clinicians facing dizzy patients on a daily basis were aware thatthis clinical and instrumental approach was oversimplified and reductionistic.Indeed, they knew of two small and mysterious sensory structures hiddenwithin the bony vestibule, but largely ignored their exact role in pathophysiol-ogy and lacked the techniques to investigate them.
During recent years, a considerable body of experimental and clinicalwork has demonstrated the direct involvement of the otolith organs in stabiliz-ing body and gaze and led to the development of specific functional tests.Thanks to these advances, an otolith semiology has emerged. We now knowthat drunken-like sensations and movements, lateropulsion, gait disturbance,visual symptoms, disorientation or erroneous sensations of upright posture,to quote but a few ill-defined or bizarre symptoms, must direct the cliniciantoward an otolith problem. New investigative tools are now available which candemonstrate the direct involvement of the utricle and saccule in the pathology.
On the 22th of January, 2000, an international meeting devoted to OtolithFunction and Disorders was held in Paris with the participation of some ofthe pioneers in the field. All aspects of otolith function were covered. AlainSans, of the INSERM at Montpellier, presented the ultrastructural features
of the two maculae with special emphasis on the neuromediators involvedin vestibular signal processing. Michael Gresty, from London, reviewed thephysiology of the otolith organs and underlined some fascinating and unexpec-ted roles of these structures in current clinical symptoms. Thomas Brandtdiscussed the principal otolith-related syndromes drawing upon his exceptionalclinical experience. Alain Berthoz developed his thoughts on the role of otolithsin the perception of movement. Lars Odvkist opened the session on clinicaland instrumental investigation of otolith function, and presented a criticalappraisal of the tests used in vestibulometric practice, with emphasis on hisexperience in eccentric rotatory testing. Following this, Christian Van Nechel,Sylvette Wiener-Vacher and Catherine de Waele reported their use of thesubjective visual vertical test, off-vertical axis rotation and click-evoked myo-genic potentials as tools for functional investigations of the otolith organs.
This volume gathers together the contributions of these authors in anattempt to provide an exhaustive view of a new field in vestibulology. We hopethat it will prove to be a valuable clinical tool concerning a system which hasremained the wild card of sensory pathology for too long.
Patrice Tran Ba HuyMichel Toupet
Tran Ba Huy P, Toupet M (eds): Otolith Functions and Disorders.Adv Otorhinolaryngol. Basel, Karger, 2001, vol 58, pp 114
............................The Mammalian Otolithic Receptors:A Complex Morphological andBiochemical Organization
Alain Sans, Claude J. Dechesne, Danielle Dememes
INSERM U 432, Montpellier, France
The vestibular sensory organs of vertebrates detect angular accelerations,by means of the ampullar receptors, and linear accelerations, by means of theotolithic receptors. The otolithic receptors consist of the utricle and the saccule,each being formed by a sensory epithelium, covered by the otoconial mem-brane, which supports calcium carbonate crystals, the otoliths or otoconia,in the form of aragonite or calcite. The utricle and saccule specifically perceivelinear accelerations induced by movements of the head in the gravity field.This sensory information is used by the central nervous system to control eyemovement and body position.
This chapter does not aim to describe the morphology of the mammalianotolithic receptors, which is already well documented, for the vestibular sensoryepithelia by Hunter-Duvar and Hinojosa , and for the otoconial membraneby Lim . Instead, it deals with correlations between anatomy and functionby taking into account the distribution of specific proteins in the varioussensory cells and their afferent and efferent nerve fibers: (1) calcium-bindingproteins in the type I and type II sensory cells and their afferent nerve fibers,and (2) the neurotransmitters involved in afferent and efferent regulation.Work carried out in our laboratory has shown regional biochemical differencesin the organization of the otolithic organs, suggesting that there may befunctional differences between the central and peripheral parts of the macularreceptors.
Fig. 1. Surface views of the rat utricle. Both utricles are similarly oriented with themedial part, with respect to the axis of the body, on the right-hand side. a Immunocytochem-ical labeling for calretinin, observed by confocal microscopy. In the striolar area (S), indicatedby a dotted line, the calyces surrounding the type I sensory cells are labeled (see fig. 5b). In theextra-striolar zones, calretinin immunostaining is detected in type II sensory cells. b Scanningelectron microscopy identifies the hair bundles. Note that the borders of the utricle areslightly raised.
The Otolithic Receptors: An Overview of Their MorphologicalCharacteristics (schematic diagram fig. 7a)
Scanning Electron MicroscopyThe Utricle. The utricular macula is kidney-shaped, with the concave
part in the medial position and the convex part in the lateral position (fig. 1).In some mammals, such as rodents, the anterior part is tilted at an angleof 30 from the horizontal. In humans, the utricle is in the horizontal planewhen the head is held in the vertical position. The sensory surface is coveredby the sensory hair bundles. This sensory epithelium is covered by a gelatinousmembrane, the