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https://www.readbyqxmd.com/read/29142084/impaired-vestibular-responses-in-internuclear-ophthalmoplegia-association-and-dissociation
#1
Seo-Young Choi, Hyo-Jung Kim, Ji-Soo Kim
OBJECTIVE: To determine the role of the medial longitudinal fasciculus (MLF) in conveying vestibular signals. METHODS: In 10 patients with isolated acute unilateral internuclear ophthalmoplegia (INO) due to an acute stroke, we performed comprehensive vestibular evaluation using video-oculography, head impulse tests with a magnetic search coil technique, bithermal caloric tests, tests for the ocular tilt reaction, and measurements of subjective visual vertical and cervical and ocular vestibular evoked myogenic potentials (VEMPs)...
November 15, 2017: Neurology
https://www.readbyqxmd.com/read/28919878/postural-control-in-bilateral-vestibular-failure-its-relation-to-visual-proprioceptive-vestibular-and-cognitive-input
#2
Andreas Sprenger, Jann F Wojak, Nico M Jandl, Christoph Helmchen
Patients with bilateral vestibular failure (BVF) suffer from postural and gait unsteadiness with an increased risk of falls. The aim of this study was to elucidate the differential role of otolith, semicircular canal (SSC), visual, proprioceptive, and cognitive influences on the postural stability of BVF patients. Center-of-pressure displacements were recorded by posturography under six conditions: target visibility; tonic head positions in the pitch plane; horizontal head shaking; sensory deprivation; dual task; and tandem stance...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28844105/the-floccular-syndrome-dynamic-changes-in-eye-movements-and-vestibulo-ocular-reflex-in-isolated-infarction-of-the-cerebellar-flocculus
#3
Dario Andres Yacovino, Manuel Perez Akly, Leonel Luis, David S Zee
The cerebellar flocculus is a critical structure involved in the control of eye movements. Both static and dynamic abnormalities of the vestibulo-ocular reflex (VOR) have been described in animals with experimental lesions of the flocculus/paraflocculus complex. In humans, lesions restricted to the flocculus are rare so they can become an exceptional model to contrast with the clinical features in experimental animals or in patients with more generalized cerebellar diseases. Here, we examined a 67-year-old patient with an acute vestibular syndrome due to an isolated infarct of the right flocculus...
August 26, 2017: Cerebellum
https://www.readbyqxmd.com/read/28790966/randomized-controlled-study-of-a-remote-flipped-classroom-neuro-otology-curriculum
#4
Frederick Robert Carrick, Mahera Abdulrahman, Ahmed Hankir, Maksim Zayaruzny, Kinda Najem, Palita Lungchukiet, Roger A Edwards
CONTEXT: Medical Education can be delivered in the traditional classroom or via novel technology including an online classroom. OBJECTIVE: To test the hypothesis that learning in an online classroom would result in similar outcomes as learning in the traditional classroom when using a flipped classroom pedagogy. DESIGN: Randomized controlled trial. A total of 274 subjects enrolled in a Neuro-otology training program for non-Neuro-otologists of 25 h held over a 3-day period...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28063365/aging-reduces-the-high-frequency-and-short-term-adaptation-of-the-vestibulo-ocular-reflex-in-mice
#5
Serajul I Khan, Patrick P Hübner, Alan M Brichta, Doug W Smith, Americo A Migliaccio
Prevailing evidence indicates a relatively late life decline in human vestibulo-ocular reflex (VOR) function. Although mice are commonly used in mechanistic studies of vestibular function, it remains unclear whether aging produces a corresponding decline in VOR function in mice. We sought to determine how the baseline VOR and its short-term adaptation were affected by aging. We tested 8 young (3-month old) and 8 aged (30-month old-equivalent to a ∼80-year old human) C57BL/6 mice. We measured their VOR response to whole-body static tilts and during 0...
March 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/27877114/ontogenetic-development-of-vestibulo-ocular-reflexes-in-amphibians
#6
REVIEW
Francisco Branoner, Boris P Chagnaud, Hans Straka
Vestibulo-ocular reflexes (VOR) ensure gaze stability during locomotion and passively induced head/body movements. In precocial vertebrates such as amphibians, vestibular reflexes are required very early at the onset of locomotor activity. While the formation of inner ears and the assembly of sensory-motor pathways is largely completed soon after hatching, angular and translational/tilt VOR display differential functional onsets and mature with different time courses. Otolith-derived eye movements appear immediately after hatching, whereas the appearance and progressive amelioration of semicircular canal-evoked eye movements is delayed and dependent on the acquisition of sufficiently large semicircular canal diameters...
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/27385797/contribution-of-intravestibular-sensory-conflict-to-motion-sickness-and-dizziness-in-migraine-disorders
#7
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 postrotational tilt paradigm generated a conflict between canal cues (which indicate the head is rotating) and 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 vestibuloocular reflex and shifting of the rotational axis of the vestibuloocular reflex toward the earth vertical...
October 1, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/26969184/impaired-tilt-suppression-of-post-rotatory-nystagmus-and-cross-coupled-head-shaking-nystagmus-in-cerebellar-lesions-image-mapping-study
#8
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...
February 2017: Cerebellum
https://www.readbyqxmd.com/read/26597305/plasticity-of-the-human-vestibulo-ocular-reflex-during-off-vertical-axis-rotation
#9
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
https://www.readbyqxmd.com/read/26239221/vestibular-evoked-myogenic-potentials-in-central-vestibular-disorders
#10
REVIEW
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
https://www.readbyqxmd.com/read/23979117/-cardinal-symptom-vertigo-from-the-neurologist-s-perspective
#11
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
https://www.readbyqxmd.com/read/23788133/listing-s-plane-and-the-3d-vor-in-microgravity-the-role-of-the-otolith-afferences
#12
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
https://www.readbyqxmd.com/read/23619994/gentamicin-induced-bilateral-vestibulopathy-in-rabbits-vestibular-dysfunction-and-histopathology
#13
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
https://www.readbyqxmd.com/read/23370610/isolated-floccular-infarction-impaired-vestibular-responses-to-horizontal-head-impulse
#14
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
https://www.readbyqxmd.com/read/23288313/-vertigo-and-dizziness-the-neurologist-s-perspective
#15
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
https://www.readbyqxmd.com/read/22704987/the-tangential-nucleus-controls-a-gravito-inertial-vestibulo-ocular-reflex
#16
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
https://www.readbyqxmd.com/read/22673321/spatial-and-temporal-properties-of-eye-movements-produced-by-electrical-stimulation-of-semicircular-canal-afferents
#17
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
https://www.readbyqxmd.com/read/22517315/pharmaceutical-countermeasures-have-opposite-effects-on-the-utricles-and-semicircular-canals-in-man
#18
RANDOMIZED CONTROLLED TRIAL
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
https://www.readbyqxmd.com/read/22427572/differential-lateral-rectus-compartmental-contraction-during-ocular-counter-rolling
#19
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
https://www.readbyqxmd.com/read/22254795/vestibular-prosthesis-tested-in-rhesus-monkeys
#20
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
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