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Vestibulo ocular reflex

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https://www.readbyqxmd.com/read/28895171/effect-of-aging-and-direction-of-impulse-in-video-head-impulse-test
#1
Tae Hwan Kim, Min-Beom Kim
OBJECTIVE: The aim of this study was to identify the difference of gain value in the video head impulse test (vHIT) according to the age of the patient and the direction of the impulse. METHOD: All participants were subjected to vHIT with horizontal semicircular canal (HSCC). vHIT with vertical canal (posterior and anterior semicircular canal [PSCC and ASCC]) additionally was performed in 434 participants. RESULTS: The mean vestibulo-ocular reflex (VOR) gain was maintained in patients in the HSCC at below 70 years (1...
September 12, 2017: Laryngoscope
https://www.readbyqxmd.com/read/28879396/vestibulo-ocular-reflex-deficits-with-medial-longitudinal-fasciculus-lesions
#2
Swee T Aw, Luke Chen, Michael J Todd, Michael H Barnett, G Michael Halmagyi
The medial longitudinal fasciculus (MLF) is the final common pathway for all conjugate adducting horizontal eye movements, as well as for the vertical-torsional vestibulo-ocular reflex (VOR). MLF lesion causes adduction paresis of ipsilesional (adducting) eye with dissociated nystagmus of contralesional (abducting) eye-the well-known clinical syndrome of internuclear ophthalmoplegia (INO). We measured the VOR stimulation and also any catch-up saccades, from individual semicircular canal (SCC) evoked by the head impulse test (HIT), using head and binocular 3-dimensional scleral search coils in 27 multiple sclerosis (MS) patients, 8 with unilateral, 19 with bilateral INO...
September 6, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28877495/wave-mechanics-of-the-vestibular-semicircular-canals
#3
Marta M Iversen, Richard D Rabbitt
The semicircular canals are biomechanical sensors responsible for detecting and encoding angular motion of the head in 3D space. Canal afferent neurons provide essential inputs to neural circuits responsible for representation of self-position/orientation in space, and to compensatory circuits including the vestibulo-ocular and vestibulo-collic reflex arcs. In this work we derive, to our knowledge, a new 1D mathematical model quantifying canal biomechanics based on the morphology, dynamics of the inner ear fluids, and membranous labyrinth deformability...
September 5, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28868046/a-novel-saccadic-strategy-revealed-by-suppression-head-impulse-testing-of-patients-with-bilateral-vestibular-loss
#4
Catherine de Waele, Qiwen Shen, Christophe Magnani, Ian S Curthoys
OBJECTIVE: We examined the eye movement response patterns of a group of patients with bilateral vestibular loss (BVL) during suppression head impulse testing. Some showed a new saccadic strategy that may have potential for explaining how patients use saccades to recover from vestibular loss. METHODS: Eight patients with severe BVL [vestibulo-ocular reflex (VOR) gains less than 0.35 and absent otolithic function] were tested. All patients were given the Dizziness Handicap Inventory and questioned about oscillopsia during abrupt head movements...
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
#5
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/28834895/pseudo-spontaneous-nystagmus-in-horizontal-semicircular-canal-canalolithiasis
#6
Dong Hyuk Im, Young Soo Yang, Hyerang Choi, Seongjun Choi, Jung Eun Shin, Chang-Hee Kim
Benign paroxysmal positional vertigo (BPPV) involving horizontal semicircular canal (HSCC) is characterized by direction-changing positional nystagmus (DCPN) in a supine roll test, and the occurrence of spontaneous nystagmus in HSCC BPPV has been reported recently. The aim of this study is to investigate the characteristics of pseudo-spontaneous nystagmus (PSN) in patients with HSCC canalolithiasis, and evaluate the effect of the presence of PSN on treatment outcome.Between April 2014 and January 2016, 75 and 59 patients with HSCC canalolithiasis and cupulolithiasis, respectively, were enrolled...
August 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28821659/stim1-regulates-somatic-ca-2-signals-and-intrinsic-firing-properties-of-cerebellar-purkinje-neurons
#7
Changhyeon Ryu, Dong Cheol Jang, Dayoon Jung, Yong Gyu Kim, Hyun Geun Shim, Hyun-Hee Ryu, Yong-Seok Lee, David J Linden, Paul F Worley, Sang Jeong Kim
Control of Ca(2+) flux between the cytosol and intracellular Ca(2+) stores is essential for maintaining normal cellular function. It has been well established in both neuronal and non-neuronal cells that stromal interaction molecule 1 (STIM1) initiates and regulates refilling Ca(2+) into the endoplasmic reticulum (ER). Here, we describe a novel, additional role for STIM1, regulation of free cytosolic Ca(2+) and consequent control of spike firing in neurons. Among central neurons, cerebellar Purkinje neurons express the highest level of STIM1 and they fire continuously in the absence of stimulation, making somatic Ca(2+) homeostasis of particular importance...
August 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28814637/asymmetric-vestibular-stimulation-reveals-persistent-disruption-of-motion-perception-in-unilateral-vestibular-lesions
#8
Roberto Panichi, Mario Faralli, Rosa Bruni, Artemis Kiriakarely, Chiara Occhigrossi, Aldo Ferraresi, Adolfo M Bronstein, Vito Enrico Pettorossi
Self-motion perception was studied in patients with unilateral vestibular lesions (UVL) due to acute vestibular neuritis at 1 week, 4, 8 and 12 months after the acute episode. We assessed vestibularly-mediated self-motion perception by measuring the error in reproducing the position of a remembered visual target at the end of 4 cycles of asymmetric whole-body rotation. The oscillatory stimulus consists of a slow (0.09Hz) and a fast (0.38Hz) half cycle. A large error was present in UVL patients when the slow half cycle was delivered towards the lesion side, but minimal towards the healthy side...
August 16, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28807728/vestibulo-ocular-reflex-abnormality-in-parkinson-s-disease-detected-by-video-head-impulse-test
#9
Wen Lv, Qiongfeng Guan, Xingyue Hu, Jiaqi Chen, Hong Jiang, Lisan Zhang, Weinv Fan
BACKGROUND: Parkinson's disease (PD) is a common neurodegenerative disease characterized by dopaminergic neuronal loss. The underlying cause of PD is unknown. OBJECTIVE: To assess the clinical relevance of vestibular-ocular reflex (VOR) gain in patients with PD, especially those in the early stages. METHODS: Sixty-three PD patients and 56 control healthy individuals were enrolled in this study between Mar 2015 and Aug 2015. VOR gains were determined by video head impulse test (vHIT) device...
September 14, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/28795949/a-comprehensive-gaze-stabilization-controller-based-on-cerebellar-internal-models
#10
Lorenzo Vannucci, Egidio Falotico, Silvia Tolu, Vito Cacucciolo, Paolo Dario, Henrik Hautop Lund, Cecilia Laschi
Gaze stabilization is essential for clear vision; it is the combined effect of two reflexes relying on vestibular inputs: the vestibulocollic reflex (VCR), which stabilizes the head in space and the vestibulo-ocular reflex (VOR), which stabilizes the visual axis to minimize retinal image motion. The VOR works in conjunction with the opto-kinetic reflex (OKR), which is a visual feedback mechanism that allows to move the eye at the same speed as the observed scene. Together they keep the image stationary on the retina...
August 10, 2017: Bioinspiration & Biomimetics
https://www.readbyqxmd.com/read/28767521/disabling-central-paroxysmal-positioning-upbeat-nystagmus-and-vertigo-associated-with-the-presence-of-anti-glutamic-acid-decarboxylase-antibodies
#11
Ana I Martins, João N Carvalho, Ana M Amorim, Argemiro Geraldo, Eric Eggenberger, João Lemos
An immune attack by anti-glutamic acid decarboxylase (GAD) antibodies is believed to cause a deficiency in gamma-aminobutyric acid-mediated neurotransmission in the cerebellum. This, in turn, leads to several eye movement disorders, including spontaneous downbeat (DBN) and periodic alternating nystagmus. We describe a 68-year-old diabetic woman with disabling paroxysmal positioning upbeat nystagmus (UBN) exclusively in the supine position, associated with asymptomatic spontaneous DBN, alternating skew deviation and hyperactive vestibulo-ocular reflex responses on head impulse testing, in whom high titers of anti-GAD antibodies were detected...
August 1, 2017: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
https://www.readbyqxmd.com/read/28755310/core-body-temperature-effects-on-the-mouse-vestibulo-ocular-reflex
#12
Patrick P Hübner, Serajul I Khan, David M Lasker, Americo A Migliaccio
Core body temperature has been shown to affect vestibular end-organ and nerve afferents so that their resting discharge rate and sensitivity increase with temperature. Our aim was to determine whether these changes observed in extracellular nerve recordings of anaesthetized C57BL/6 mice corresponded to changes in the behavioural vestibulo-ocular reflex (VOR) of alert mice. The VOR drives eye rotations to keep images stable on the retina during head movements. We measured the VOR gain (eye velocity/head velocity) and phase (delay between vestibular stimulus and response) during whole-body sinusoidal rotations ranging 0...
July 28, 2017: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/28723718/three-dimensional-head-mounted-gaming-task-procedure-maximizes-effects-of-vestibular-rehabilitation-in-unilateral-vestibular-hypofunction-a-randomized-controlled-pilot-trial
#13
Alessandro Micarelli, Andrea Viziano, Ivan Augimeri, Domenico Micarelli, Marco Alessandrini
Considering the emerging advantages related to virtual reality implementation in clinical rehabilitation, the aim of the present study was to discover possible (i) improvements achievable in unilateral vestibular hypofunction patients using a self-assessed head-mounted device (HMD)-based gaming procedure when combined with a classical vestibular rehabilitation protocol (HMD group) as compared with a group undergoing only vestibular rehabilitation and (ii) HMD procedure-related side effects. Therefore, 24 vestibular rehabilitation and 23-matched HMD unilateral vestibular hypofunction individuals simultaneously underwent a 4-week rehabilitation protocol...
July 18, 2017: International Journal of Rehabilitation Research. Revue Internationale de Recherches de Réadaptation
https://www.readbyqxmd.com/read/28719825/degeneration-of-the-vestibular-nerve-in-unilateral-meniere-s-disease-evaluated-by-galvanic-vestibular-evoked-myogenic-potentials
#14
Chih-Ming Chang, Yi-Ho Young, Fu-Shan Jaw, Chi-Te Wang, Po-Wen Cheng
OBJECTIVE: The staging system of Meniere's disease utilizes audiograms to probe cochlear dysfunction. We explored the addition of galvanic vestibular-evoked myogenic potentials (VEMP) to further explore vestibular function. METHODS: Seventy patients with unilateral Meniere's disease were enrolled in this study. Within 2weeks of diagnosis, all subjects underwent pure tone audiometry, cervical and ocular VEMP, and caloric test. The prevalence of abnormal tests and the VEMP characteristic parameters such as latencies and amplitudes were analyzed...
September 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/28716764/influence-of-time-and-direction-information-on-video-head-impulse-gains
#15
Oğuz Yılmaz, Ersoy Öz, Serkan Kurt, Öyküm Esra Aşkın, Elifnur Taşdemir, Berna Özge Mutlu, Ahmet Keleş, Raşit Cevizci
OBJECTIVE: The objective of this study was to establish which factor leads to a higher vestibulo-ocular reflex (VOR) gain: the timing of the movement or the direction of the movement. For this purpose, healthy volunteers were examined under three conditions: (1) when they were informed about the timing of the head movement; (2) when they were informed about the direction of the head movement; and (3) when they knew both the timing and the direction of the head movement. MATERIALS AND METHODS: This study included data from 19 participants between the ages of 20 and 23 years with no neurological or vestibular ailments...
July 17, 2017: Journal of International Advanced Otology
https://www.readbyqxmd.com/read/28649224/the-video-head-impulse-test
#16
REVIEW
G M Halmagyi, Luke Chen, Hamish G MacDougall, Konrad P Weber, Leigh A McGarvie, Ian S Curthoys
In 1988, we introduced impulsive testing of semicircular canal (SCC) function measured with scleral search coils and showed that it could accurately and reliably detect impaired function even of a single lateral canal. Later we showed that it was also possible to test individual vertical canal function in peripheral and also in central vestibular disorders and proposed a physiological mechanism for why this might be so. For the next 20 years, between 1988 and 2008, impulsive testing of individual SCC function could only be accurately done by a few aficionados with the time and money to support scleral search-coil systems-an expensive, complicated and cumbersome, semi-invasive technique that never made the transition from the research lab to the dizzy clinic...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28646272/rhesus-cochlear-and-vestibular-functions-are-preserved-after-inner-ear-injection-of-saline-volume-sufficient-for-gene-therapy-delivery
#17
Chenkai Dai, Mohamed Lehar, Daniel Q Sun, Lani Swarthout Rvt, John P Carey, Tim MacLachlan, Doug Brough, Hinrich Staecker, Alexandra M Della Santina, Timothy E Hullar, Charles C Della Santina
Sensorineural losses of hearing and vestibular sensation due to hair cell dysfunction are among the most common disabilities. Recent preclinical research demonstrates that treatment of the inner ear with a variety of compounds, including gene therapy agents, may elicit regeneration and/or repair of hair cells in animals exposed to ototoxic medications or other insults to the inner ear. Delivery of gene therapy may also offer a means for treatment of hereditary hearing loss. However, injection of a fluid volume sufficient to deliver an adequate dose of a pharmacologic agent could, in theory, cause inner ear trauma that compromises functional outcome...
August 2017: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/28640006/poor-gait-performance-is-influenced-with-decreased-vestibulo-ocular-reflex-in-poststroke-patients
#18
Tsubasa Mitsutake, Maiko Sakamoto, Kozo Ueta, Shinichiro Oka, Etsuo Horikawa
The vestibulo-ocular reflex (VOR) exerts a significant influence on gait performance. Therefore, a decrease in VOR function could worsen gait impairments in patients with poststroke hemiparesis. The effects of decreased VOR function on gait performance could be further exacerbated by aging-related physical weakness and impaired motor function of the hemiparetic lower limb. The aim of our study was to evaluate the possible synergistic effect of aging and impairment in lower extremity function and the VOR on walking ability of poststroke hemiplegic patients...
August 16, 2017: Neuroreport
https://www.readbyqxmd.com/read/28638085/differential-regulations-of-vestibulo-ocular-reflex-and-optokinetic-response-by-%C3%AE-and-%C3%AE-2-adrenergic-receptors-in-the-cerebellar-flocculus
#19
Ryo Wakita, Soshi Tanabe, Kazunari Tabei, Asako Funaki, Takuma Inoshita, Tomoo Hirano
Norepinephrine modulates synaptic plasticity in various brain regions and is implicated in memory formation, consolidation and retrieval. The cerebellum is involved in motor learning, and adaptations of the vestibulo-ocular reflex (VOR) and optokinetic response (OKR) have been studied as models of cerebellum-dependent motor learning. Previous studies showed the involvement of adrenergic systems in the regulation of VOR, OKR and cerebellar synaptic functions. Here, we show differential contributions of β- and α2-adrenergic receptors in the mouse cerebellar flocculus to VOR and OKR control...
June 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28616773/intracochlear-schwannoma-tumor-removal-via-subtotal-cochleoectomy-and-partial-cochlear-reconstruction-with-preservation-of%C3%A2-semicircular-canal-function
#20
S K Plontke, S Kösling, N Pazaitis, T Rahne
We report about a patient, who in 2005, as a 37-year-old, experienced a sudden, mild to moderate, mid-frequency sensorineural hearing loss in the right ear, along with tinnitus and mild dizziness. MRI of the temporal bone revealed a very small (1 mm) enhancing lesion in the second turn of the right cochlea after injection of contrast medium. Hearing gradually deteriorated, with complete hearing loss in 2015. At this time, an MRI scan showed a lesion completely filling the cochlea.The tumor was removed through a subtotal cochleoectomy...
June 14, 2017: HNO
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