Perception of verticality and vestibular disorders in the roll plane
- 1Ludwig Maximilian University of Munich, Germany
Objective: To review current knowledge of the perception of verticality, its normal function and disorders. This is based on an integrative graviceptive input from the otolith organs and the vertical semicircular canals.
Methods: The special focus is on human psychophysics, neurophysiological and imaging data on the adjustments of subjective visual vertical (SVV) and the subjective postural vertical. Furthermore, the mathematical modeling of specific vestibular cell functions for orientation in space in rodents and in patients will also be reviewed.
Results: Pathological tilts of the SVV in the roll plane are the most sensitive and frequent clinical vestibular signs of unilateral lesions extending from the labyrinths via the brainstem and thalamus to the parieto-insular vestibular cortex. Due to crossings of ascending graviceptive fibers, peripheral vestibular and pontomedullary lesions cause ipsilateral tilts of the SVV, whereas pontomesencephalic lesions cause contralateral tilts. In contrast, SVV tilts, which are measured in unilateral vestibular lesions at thalamic and cortical levels, have two different characteristic features: (i) they may be ipsi- or contralateral, and (ii) they are smaller than those found in lower brainstem or peripheral lesions. Motor signs such as head tilt and body lateropulsion, components of ocular tilt reaction, are typical for vestibular lesions of the peripheral vestibular organ and the pontomedullary brainstem (vestibular nucleus). They are less frequent in midbrain lesions (interstitial nucleus of Cajal) and rare in cortical lesions. Isolated body lateropulsion is chiefly found in caudal lateral medullary brainstem lesions. Vestibular function in the roll plane and its disorders can be mathematically modeled by an attractor model of angular head velocity cell and head direction cell function.
Disorders manifesting with misperception of the body vertical are the pusher syndrome, the progressive supranuclear palsy, or the normal pressure hydrocephalus; they may affect roll and/or pitch plane.
Conclusion: Clinical determinations of the SVV are easy and reliable. They indicate acute unilateral vestibular dysfunctions, the causative lesion of which extends from labyrinth to cortex. They allow precise topographical diagnosis of side and level. SVV tilts may coincide with or differ from the perception of body vertical, e.g. in isolated body lateropulsion.
Keywords: Subjective postural vertical (SPV), Subjective visual vertical (SVV), Ocular tilt reaction, Interstitial nucleus of Cajal, Progressive supranuclear palsy (PSP), Normal pressure hydrocephalus (NPH), rostral interstitial nucleus of the medial longitudinal fascicle
Received: 20 Sep 2018;
Accepted: 08 Feb 2019.
Edited by:Christian Van Nechel, Clinique des Vertiges, Belgium
Reviewed by:Fred W. Mast, University of Bern, Switzerland
Alexander A. Tarnutzer, University of Zurich, Switzerland
Copyright: © 2019 Dieterich and Brandt. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Marianne Dieterich, Ludwig Maximilian University of Munich, Munich, Germany, Marianne.Dieterich@med.uni-muenchen.de