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Dario A Yacovino, John B Finlay
Ménière's attack has been shown to temporarily alter the vestibuloocular reflex (VOR). A patient with unilateral Ménière's disease was serially evaluated with the video Head Impulse Test during single, untreated episodes of acute vertigo. Spontaneous nystagmus activity was concurrently recorded in order to establish the three typical phases of Ménière's attack (irritative, paralytic, and recovery) and correlate them with VOR performance. The onset of attack was associated with a quick change in VOR gain on the side of the affected ear...
2016: Case Reports in Otolaryngology
Bela Büki, Manuela Hanschek, Heinz Jünger
OBJECTIVE: In this retrospective study, the aim of the authors was to examine the frequency of involvement of the individual semicircular canals (SCCs) in vestibular neuritis (VN) and to assess the degree of long-term recovery. A secondary aim was to retrospectively determine the usefulness of a three-step bedside oculomotor test (the HINTS-test) for the differential diagnosis of peripheral VN. METHODS: 44 cases were evaluated during the acute phase and approximately two months later...
August 18, 2016: Auris, Nasus, Larynx
D V Lychakov
The review contains data on functional shifts in fishes, amphibians and birds caused by changes in the otolith system operation after stay under weightlessness conditions. These data are of theoretical and practical significance and are important to resolve some fundamental problems of vestibulogy. The analysis of the results of space experiments has shown that weightlessness conditions do not exert a substantial impact on formation and functional state of the otolith system in embryonic fishes, amphibians and birds developed during space flight...
January 2016: Zhurnal Evoliutsionnoĭ Biokhimii i Fiziologii
Derek M Miller, James F Baker, W Zev Rymer
OBJECTIVE: Aberrant vestibular nuclear function is proposed to be a principle driver of limb muscle spasticity after stroke. Although spasticity does not manifest in ocular muscles, we sought to determine whether altered cortical modulation of ascending vestibuloocular pathways post-stroke could impact the excitability of ocular motoneurons. METHODS: Nineteen chronic stroke survivors, aged 49-68 yrs. were enrolled. Vestibular evoked myogenic potentials (VEMPs) were recorded from the inferior oblique muscles of the eye using surface EMG electrodes...
April 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Marta Martinez-Lopez, Raquel Manrique-Huarte, Nicolas Perez-Fernandez
The aim of this paper is to present for the first time the functional evaluation of each of the vestibular receptors in the six semicircular canals in a patient diagnosed with Meniere's disease during an acute attack. A 54-year-old lady was diagnosed with left Meniere's disease who during her regular clinic review suffers an acute attack of vertigo, with fullness and an increase of tinnitus in her left ear. Spontaneous nystagmus and the results in the video head-impulse test (vHIT) are shown before, during, and after the attack...
2015: Case Reports in Otolaryngology
Georgios Mantokoudis, Ali S Saber Tehrani, David E Newman-Toker
INTRODUCTION: Vertigo and dizziness are common neurological symptoms in general practice. Most patients have benign peripheral vestibular disorders, but some have dangerous central causes. Recent research has shown that bedside oculomotor examinations accurately discriminate central from peripheral lesions in those with new, acute, continuous vertigo/dizziness with nausea/vomiting, gait unsteadiness, and nystagmus, known as the acute vestibular syndrome. CASE REPORT: A 56-year-old man presented to the emergency department with acute vestibular syndrome for 1 week...
April 2015: Neurologist
Francisco Carlos Zuma E Maia, Pedro Luiz Mangabeira Albernaz, Renato Cal, Thaísa Rodrigues Brusco, Sady Seleiman da Costa
CONCLUSION: There were no changes in the function of the six semicircular canals in active fighter pilots, through the use of the video head impulse test (vHIT). These results suggest that the vestibuloocular reflex (VOR) works well at the high frequencies related to the natural head movements in this population. OBJECTIVES/HYPOTHESIS: The vestibular function in pilots has been reported as being different from that of other normal subjects. These differences are attributed to adaptation of the vestibuloocular reflex (VOR) or by habituation...
July 2015: Acta Oto-laryngologica
Tadashi Yamazaki, Soichi Nagao, William Lennon, Shigeru Tanaka
Long-term depression (LTD) at parallel fiber-Purkinje cell (PF-PC) synapses is thought to underlie memory formation in cerebellar motor learning. Recent experimental results, however, suggest that multiple plasticity mechanisms in the cerebellar cortex and cerebellar/vestibular nuclei participate in memory formation. To examine this possibility, we formulated a simple model of the cerebellum with a minimal number of components based on its known anatomy and physiology, implementing both LTD and long-term potentiation (LTP) at PF-PC synapses and mossy fiber-vestibular nuclear neuron (MF-VN) synapses...
March 17, 2015: Proceedings of the National Academy of Sciences of the United States of America
Juliana T Wagatsuma, Maurício Deschk, Beatriz P Floriano, Joana Z Ferreira, Heitor Fioravanti, Isabela F Gasparello, Valéria N L S Oliva
OBJECTIVE: To compare the anesthetic efficacy and adverse effects associated with peribulbar injection of ropivacaine (1% solution) performed with and without ultrasound guidance (UG) in dogs. ANIMALS: 15 dogs without ophthalmologic abnormalities. PROCEDURES: Each dog was sedated and anesthetized. A peribulbar injection of ropivacaine (1% solution; 0.3 mL/kg) was performed with UG in 1 eye and without UG in the contralateral eye (control)...
December 2014: American Journal of Veterinary Research
Michael D Mauk, Wenke Li, Andrei Khilkevich, Hunter Halverson
The analysis of well-defined behaviors that require the cerebellum has helped reveal many key mechanisms operating in the cerebellum to mediate learning and feed-forward prediction. These systems include eyelid conditioning, adaptation of the vestibuloocular reflex, smooth pursuit eye movements, and arm-reaching tasks. This review focuses specifically on the variety of findings that have come from the use of eyelid conditioning to study the cerebellum. Phenomena discussed include sites and rules for plasticity, temporal coding and mechanisms of timing, cerebellar control of climbing fibers and its role in bidirectional learning, extinction of conditioned responses, and the phenomenon of savings...
2014: International Review of Neurobiology
John S Stahl, Zachary C Thumser
Mutation of the Cacna1a gene for the P/Q (CaV2.1) calcium channel invariably leads to cerebellar dysfunction. The dysfunction has been attributed to disrupted rhythmicity of cerebellar Purkinje cells, but the hypothesis remains unproven. If irregular firing rates cause cerebellar dysfunction, then the irregularity and behavioral deficits should covary in a series of mutant strains of escalating severity. We compared firing irregularity in floccular and anterior vermis Purkinje cells in the mildly affected rocker and moderately affected tottering Cacna1a mutants and normal C57BL/6 mice...
November 15, 2014: Journal of Neurophysiology
David J Szmulewicz, Linda Seiderer, G Michael Halmagyi, Elsdon Storey, Leslie Roberts
INTRODUCTION: Cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS) is a recently described multisystem ataxia defined by the presence of cerebellar ataxia, bilateral vestibulopathy, and a somatosensory deficit. The characteristic clinical sign is an abnormal visually enhanced vestibuloocular reflex. The somatosensory deficit contributes to a significant level of disability in CANVAS. METHODS: This study was a neurophysiological investigation of 14 patients with CANVAS...
April 2015: Muscle & Nerve
Eric R Eggenberger
PURPOSE OF REVIEW: The components of the efferent ocular motor network include supranuclear, nuclear, internuclear, infranuclear, neuromuscular junction, and muscle. Within this schema, clinicians are often least acquainted with the supranuclear components; however, derangement of this system is a common cause of ocular dysmotility and diplopia. This article will provide the neurologist with an overview of the anatomy and clinical aspects of the supranuclear ocular motor control systems...
August 2014: Continuum: Lifelong Learning in Neurology
Joo Hyun Park, Hyo Jung Kim, Ji-Soo Kim, Ja-Won Koo
A sound- and pressure-induced vestibuloocular reflex (VOR) has been described as vertical and torsional in superior canal dehiscence (SCD), and the rotational axes of induced VOR have been assumed to fit with the axis of the affected superior semicircular canal (SC). However, it has been difficult to characterize the pattern of vibration-induced VOR (ViVOR). We aimed to characterize the pattern of ViVOR by comparing the intensity and the axis of ViVOR with several clinical parameters of SCD. Ten symptomatic SCD patients were recruited...
2014: Audiology & Neuro-otology
Guy Cheron, Bernard Dan, Javier Márquez-Ruiz
The role of cerebellar plasticity has been increasingly recognized in learning. The privileged relationship between the cerebellum and the inferior olive offers an ideal circuit for attempting to integrate the numerous evidences of neuronal plasticity into a translational perspective. The high learning capacity of the Purkinje cells specifically controlled by the climbing fiber represents a major element within the feed-forward and feedback loops of the cerebellar cortex. Reciprocally connected with the basal ganglia and multimodal cerebral domains, this cerebellar network may realize fundamental functions in a wide range of behaviors...
2013: Neural Plasticity
Hans Straka, Robert Baker
Central vestibular neurons form identifiable subgroups within the boundaries of classically outlined octavolateral nuclei in primitive vertebrates that are distinct from those processing lateral line, electrosensory, and auditory signals. Each vestibular subgroup exhibits a particular morpho-physiological property that receives origin-specific sensory inputs from semicircular canal and otolith organs. Behaviorally characterized phenotypes send discrete axonal projections to extraocular, spinal, and cerebellar targets including other ipsi- and contralateral vestibular nuclei...
2013: Frontiers in Neural Circuits
M Glickstein, C Yeo
People with profound memory deficits can acquire new motor skills, even though on each day of training they may be unaware of having seen the training apparatus before. Similarly, rabbits can acquire or retain a conditioned nictitating membrane response despite massive lesions of the hippocampus or the cerebral cortex. Both lines of evidence suggest that sub-cortical structures may be sufficient for many forms of motor learning. One possible locus for motor learning is the cerebellum. This article traces the history of our knowledge of structure and function of the cerebellum...
1990: Journal of Cognitive Neuroscience
Sarah Khan, Richard Chang
INTRODUCTION: A sense of proper sensory processing of head motion and the coordination of visual and postural movements to maintain equilibrium is critical to everyday function. The vestibular system is an intricate organization that involves multiple levels of sensory processing to achieve this goal. PURPOSE: This chapter provides an overview of the anatomical structures and pathways of the vestibular system. SUMMARY: The five major vestibular structures are located in the inner ear and include: the utricle, the saccule, and the lateral, superior, and posterior semicircular canals...
2013: NeuroRehabilitation
Miriam S Welgampola, Elijane Ramsay, Michael J Gleeson, Brian L Day
OBJECTIVE: We investigated the potential of galvanic vestibular stimulation (GVS) to quantify lateralised asymmetry of the vestibulospinal pathways by measuring balance responses to monaural GVS in 10 subjects with vestibular schwannoma and 22 healthy control subjects. METHODS: Subjects standing without vision were stimulated with 3 s, 1 mA direct current stimuli delivered monaurally. The mean magnitude and direction of the evoked balance responses in the horizontal plane were measured from ground-reaction forces and from displacement and velocity of the trunk...
September 2013: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
L E Walther, R Huelse, K Blättner, M B Bloching, A Blödow
Intratympanic gentamicin treatment (IGT) is an evidence-based therapeutic option for recurrent vertigo attacks in Ménière's disease (MD). Today, in MD it is possible to monitor changes of vestibular receptor function, induced by IGT, with objective test methods such as the video head impulse test (vHIT) and cervical and ocular vestibular evoked myogenic potentials (cVEMP, oVEMP) in a dynamic, time-and frequency-dependent manner. We report on a 65-year-old female patient with recurrent vertigo attacks in a right-sided MD, where receptor function was followed up before and up to 4 weeks after IGT (time dynamic)...
2013: Case Reports in Otolaryngology
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