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tilt VOR

Joanne Wang, Richard F Lewis
Migraine is associated with enhanced motion sickness susceptibility and can cause episodic vertigo (vestibular migraine, VM), but the mechanisms relating migraine to these vestibular symptoms remain uncertain. We tested the hypothesis that the central integration of rotational cues (from the semicircular canals) and gravitational cues (from the otolith organs) is abnormal in migraine patients. A post-rotational tilt paradigm generated a conflict between the canal cues (which indicate the head is rotating) and the otolith cues (which indicate the head is tilted and stationary), and eye movements were measured to quantify two behaviors that are thought to minimize this conflict - suppression and reorientation of the central angular velocity signal, evidenced by attenuation ("dumping") of the vestibulo-ocular reflex (VOR) and shifting of the VOR's rotational axis towards the earth-vertical...
July 6, 2016: Journal of Neurophysiology
Sun-Uk Lee, Jeong-Yoon Choi, Hyo-Jung Kim, Jeong-Jin Park, David S Zee, Ji-Soo Kim
We sought to determine the cerebellar structures responsible for tilt suppression of post-rotatory nystagmus. We investigated ocular motor findings and MRI lesions in 73 patients with isolated cerebellar lesions who underwent recording of the vestibulo-ocular reflex (VOR) using rotatory chair tests. Tilt suppression of post-rotatory nystagmus was diminished in 27 patients (27/73, 37.0 %). The gains of the VOR and the TCs of per- and post-rotatory nystagmus did not differ between the patients with diminished and with normal tilt suppression...
March 11, 2016: Cerebellum
Masatoshi Akutsu, Akemi Sugita-Kitajima, Koshi Mikami, Izumi Koizuka
OBJECTIVE: We investigated whether adaptive plasticity of the vestibulo-ocular reflex in humans occurs in response to visual-vestibular conflict stimulation during rotation about a 30° incline (off-vertical earth axis rotation, OVAR). METHODS: Subjects were 26 healthy adults (17 males and 9 females), ranging in age from 22 to 33 years (mean: 24.4) with no history of neurotological symptoms. Each testing session consisted of a pre-test, an adaptation period, and a post-test...
August 2016: Auris, Nasus, Larynx
Sun-Young Oh, Hyo-Jeong Kim, Ji-Soo Kim
Vestibular-evoked myogenic potentials (VEMPs) are short latency manifestations of vestibulo-ocular and vestibulocollic reflexes that originate from the utricle and saccule. Although cervical and ocular VEMPs have mostly been applied to peripheral vestibular disorders, the characteristics and the diagnostic values of VEMPs have been expanded to assess the function of the central otolithic pathways. In the central nervous system, the cervical VEMPs (cVEMPs) are mediated by the vestibular nuclei and uncrossed medial vestibulospinal tract descending in the lower brainstem and spinal cord...
February 2016: Journal of Neurology
M Strupp, C Muth, N Böttcher, O Bayer, J Teufel, K Feil, T Bremova, O Kremmyda, C S Fischer
In most patients with vertigo, the first and clinically most important question posed to neurologists is whether it is a central or a peripheral syndrome. In more than 90 % of cases, this differentiation is made possible by systematically recording the patient history (asking about the type of vertigo, the duration, triggers and accompanying symptoms) and conducting a physical examination. Particularly in the case of acute vertigo disorders, a five-step procedure has proven useful: 1. A cover test to look for vertical divergence (skew deviation) as a central sign and component of the ocular tilt reaction (OTR); 2...
September 2013: HNO
Andrew H Clarke, K Just, W Krzok, U Schönfeld
The study addresses the question as to what extent the otolith-mediated gravity vector maintains the stability of the coordinate frames of the vestibulo-ocular reflex and the oculomotor system, described by Listing's Plane. Under normal 1 G conditions it has been demonstrated in the monkey that Listing's Plane (LP) and the 3D vestibulo-ocular response (3D-VOR) are close to collinear [10]. In the present study the coordinate frames of the oculomotor system and the three-dimensional vestibulo-ocular reflex (3D-VOR) system were measured under one-g gravity conditions and during a period of prolonged microgravity, on-board the International Space Station (ISS)...
January 1, 2013: Journal of Vestibular Research: Equilibrium & Orientation
Hyo Jung Kim, Jin Ok Lee, Ja Won Koo, Ji-Soo Kim, Jaejun Ban
OBJECTIVES/HYPOTHESIS: Bilateral vestibulopathy (BV) is a mostly persistent and disabling disorder causing dizziness, oscillopsia, and imbalance during locomotion. The animal model is a prerequisite for experimental investigation on prevention and treatment of this disorder. The aim of this study was to determine the vestibular dysfunction and histopathology in rabbits with gentamicin-induced BV. STUDY DESIGN: Prospective animal study in rabbits. METHODS: We performed intratympanic gentamicin (ITGM) injections in 12 Lionhead rabbits...
November 2013: Laryngoscope
Hong-Kyun Park, Ji-Soo Kim, Michael Strupp, David S Zee
Isolated floccular infarction is extremely rare, and impairments of the vestibulo-ocular reflex (VOR) have not been explored in humans with isolated floccular lesions. The purpose of this study was to examine and report selective impairment of VOR in response to high acceleration using head impulse in a patient with isolated floccular infarction. The patient underwent bedside and laboratory evaluation of vestibular function, which included video-oculography, ocular torsion and the subjective visual vertical, cervical and ocular vestibular-evoked myogenic potentials, bithermal caloric irrigation, rotatory chair test, and the head impulse test (HIT) using search coils...
June 2013: Journal of Neurology
M Strupp
The spectrum of diagnoses of patients with dizziness as the leading symptom who consult a neurologist does not differ greatly from the spectrum of those who consult ear nose and throat (ENT) specialists or general practitioners (GP). The most frequent forms are benign paroxysmal positioning vertigo (BPPV), phobic postural vertigo, central vertigo disorders, Menière's disease, vestibular neuritis and bilateral vestibulopathy. However, the first and most important question that is posed to neurologists is whether it is a central or peripheral syndrome...
January 2013: Der Ophthalmologe: Zeitschrift der Deutschen Ophthalmologischen Gesellschaft
Isaac H Bianco, Leung-Hang Ma, David Schoppik, Drew N Robson, Michael B Orger, James C Beck, Jennifer M Li, Alexander F Schier, Florian Engert, Robert Baker
BACKGROUND: Although adult vertebrates sense changes in head position by using two classes of accelerometer, at larval stages zebrafish lack functional semicircular canals and rely exclusively on their otolithic organs to transduce vestibular information. RESULTS: Despite this limitation, we find that larval zebrafish perform an effective vestibulo-ocular reflex (VOR) that serves to stabilize gaze in response to pitch and roll tilts. By using single-cell electroporations and targeted laser ablations, we identified a specific class of central vestibular neurons, located in the tangential nucleus, that are essential for the utricle-dependent VOR...
July 24, 2012: Current Biology: CB
Richard F Lewis, Csilla Haburcakova, Wangsong Gong, Faisal Karmali, Daniel M Merfeld
To investigate the characteristics of eye movements produced by electrical stimulation of semicircular canal afferents, we studied the spatial and temporal features of eye movements elicited by short-term lateral canal stimulation in two squirrel monkeys with plugged lateral canals, with the head upright or statically tilted in the roll plane. The electrically induced vestibuloocular reflex (eVOR) evoked with the head upright decayed more quickly than the stimulation signal provided by the electrode, demonstrating an absence of the classic velocity storage effect that improves the dynamics of the low-frequency VOR...
September 2012: Journal of Neurophysiology
Aurélie P Weerts, Guido De Meyer, Griet Pauwels, Robby Vanspauwen, John L Dornhoffer, Paul H Van de Heyning, Floris L Wuyts
INTRODUCTION: Sensory conflicts in the vestibular system lead to motion sickness of which space motion sickness (SMS) is a special case. SMS affects up to 70% of the astronauts during the first 3 days in space. The search for effective countermeasures has led to several nonpharmacological and pharmacological approaches. The current study focuses on the effects of lorazepam (1 mg), meclizine (25 mg), promethazine (25 mg), and scopolamine (0.4 mg) on the vestibular system, with special focus on the canal and otolith functions separately...
2012: Audiology & Neuro-otology
Robert A Clark, Joseph L Demer
PURPOSE: The lateral rectus (LR) and medial rectus (MR) extraocular muscles (EOMs) have largely nonoverlapping superior and inferior innervation territories, suggesting functional compartmental specialization. We used magnetic resonance imaging (MRI) in humans to investigate differential compartmental activity in the rectus EOMs during head tilt, which evokes ocular counter-rolling, a torsional vestibulo-ocular reflex (VOR). METHODS: MRI in quasi-coronal planes was analyzed during target-controlled central gaze in 90° right and left head tilts in 12 normal adults...
May 2012: Investigative Ophthalmology & Visual Science
Richard F Lewis, Csilla Haburcakova, Wangsong Gong, Daniel Lee, Conrad Wall, Lara Thompson, Daniel M Merfeld
We are studying the effectiveness of a semicircular canal prosthesis to improve postural control, perception of spatial orientation, and the VOR in rhesus monkeys with bilateral vestibular hypofunction. Balance is examined by measuring spontaneous sway of the body during quiet stance and postural responses evoked by head turns and rotation of the support surface; perception is measured with a task derived from the subjective visual vertical (SVV) test during static and dynamic rotation in the roll plane; and the angular VOR is measured during rotation about the roll, pitch, and yaw axes...
2011: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
James A Sharpe, Sunil Kumar, Arun N Sundaram
PURPOSE: This article considers vertical misalignment and torsion of the eyes that arise from disorders of vestibulo-ocular reflex (VOR) pathways. RECENT FINDINGS: Infarction of the nodulus is one of the causes of skew deviation, a vertical strabismus accompanied by torsion of the eyes and tilt of the subjective visual vertical. Vertical components of childhood strabismus may arise from dysgenesis of vestibular projections in the brainstem. If vertical misalignment decreases greatly in the supine position compared to the erect poison one may conclude that skew deviation rather than a fourth nerve palsy is responsible for the strabismus...
February 2011: Current Opinion in Neurology
Weike Mo, Fangyi Chen, Alex Nechiporuk, Teresa Nicolson
BACKGROUND: Vestibular reflexes coordinate movements or sensory input with changes in body or head position. Vestibular-evoked responses that involve the extraocular muscles include the vestibulo-ocular reflex (VOR), a compensatory eye movement to stabilize retinal images. Although an angular VOR attributable to semicircular canal stimulation was reported to be absent in free-swimming zebrafish larvae, recent studies reveal that vestibular-induced eye movements can be evoked in zebrafish larvae by both static tilts and dynamic rotations that tilt the head with respect to gravity...
2010: BMC Neuroscience
Jean Laurens, Dominik Straumann, Bernhard J M Hess
The vestibular organs in the base of the skull provide important information about head orientation and motion in space. Previous studies have suggested that both angular velocity information from the semicircular canals and information about head orientation and translation from the otolith organs are centrally processed in an internal model of head motion, using the principles of optimal estimation. This concept has been successfully applied to model behavioral responses to classical vestibular motion paradigms...
September 2010: Journal of Neurophysiology
Daniel M Merfeld, Adrian Priesol, Daniel Lee, Richard F Lewis
Among other problems, patients with vestibular problems suffer imbalance, spatial disorientation, and blurred vision. These problems lead to varying degrees of disability and can be debilitating. Unfortunately, a large number of patients with vestibular complaints cannot be diagnosed with the clinical tests available today. Nor do we have treatments for all patients that we can diagnose. These clinical problems provide challenges to and opportunities for the field of vestibular research. In this paper, we discuss some new diagnostic and treatment options that could become available for tomorrow's patients...
2010: Journal of Vestibular Research: Equilibrium & Orientation
Seong-Hae Jeong, Sun-Young Oh, Hyo-Jung Kim, Ja-Won Koo, Ji Soo Kim
The mechanisms of vestibular migraine and motion sickness remain unknown. The aims of this study were to determine interictal vestibular dysfunction in migraineurs according to associated dizziness/vertigo and motion sickness, and to find out whether impaired uvulonodular inhibition over the vestibular system underlies the vestibular symptoms and signs by measuring tilt suppression of the vestibulo-ocular reflex (VOR). One hundred and thirty-one patients with migraine [65 with vestibular migraine (MV), 41 with migrainous dizziness (MD), and 25 with migraine only (MO)] and 50 normal controls underwent evaluation of vestibular function...
June 2010: Journal of Neurology
Dominique Louise Rousie, Jean Paul Deroubaix, Olivier Joly, Jean Claude Baudrillard, Alain Berthoz
We developed a modeling procedure using CT scans or MRI data for exploring the bony and lymphatic canals of vestibular patients. We submitted 445 patients with instability and spatial de-orientation to this procedure. Out of the 445 patients, 95 had scoliosis, some of them, because malformations were suspected also had CT-scan modeling and functional tests. We focused on a never described, abnormal connection between the lymphatic lateral and posterior canal (LPCC) with a frequency of 67/445 (15%). In the scoliosis subgroup, the frequency was 52/95 (55%)...
May 2009: Annals of the New York Academy of Sciences
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