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Vestibulo ocular reflex

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https://www.readbyqxmd.com/read/28224454/effects-of-sustained-otolith-only-stimulation-on-post-rotational-nystagmus
#1
Aasef G Shaikh, David Solomon
Constant velocity rotations in darkness evoke vestibulo-ocular reflex in form of pre- and post-rotational nystagmus under cerebellar supervision. Reorientation of the head with respect to gravity, stimulating otolith and semicircular canal, during post-rotational phase rapidly suppresses the post-rotational nystagmus. We asked if pure otolith stimulation without semicircular canal signal is sufficient for the suppression of post-rotational nystagmus. The experimental paradigm comprised of on-axis rotations in the horizontal plane when the subject was sitting upright, followed by a novel stimulus that combined off-axis centrifugation in the horizontal plane with amplitude matched, yet out-of-phase, on-axis horizontal rotation-double centrifugation...
February 21, 2017: Cerebellum
https://www.readbyqxmd.com/read/28194135/inaccurate-saccades-and-enhanced-vestibulo-ocular-reflex-suppression-during-combined-eye-head-movements-in-patients-with-chronic-neck-pain-possible-implications-for-cervical-vertigo
#2
Janine L Johnston, Pierre M Daye, Glen T D Thomson
BACKGROUND: The primate ocular motor system is designed to acquire peripheral targets of interest by coordinating visual, vestibular, and neck muscle activation signals. The vestibulo-ocular reflex (VOR) is greatly reduced at the onset of large eye-head (gaze) saccades and resumes before the end of the saccades to stabilize eye-in-orbit and ensure accurate target acquisition. Previous studies have relied on manipulating head movements in normal individuals to study VOR suppression and gaze kinematics...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28192379/compensatory-saccades-are-associated-with-physical-performance-in-older-adults-data-from-the-baltimore-longitudinal-study-of-aging
#3
Yanjun Xie, Eric R Anson, Eleanor M Simonsick, Stephanie A Studenski, Yuri Agrawal
OBJECTIVE: To determine whether compensatory saccade metrics observed in the video head impulse test, specifically saccade amplitude and latency, predict physical performance. STUDY DESIGN: Cross-sectional analysis of the Baltimore Longitudinal Study of Aging, a prospective cohort study. SETTING: National Institute on Aging Intramural Research Program Clinical Research Unit in Baltimore, Maryland. PATIENTS: Community-dwelling older adults...
March 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28179894/vestibulo-ocular-reflex-stabilization-after-vestibular-schwannoma-surgery-a-story-told-by-saccades
#4
Angel Batuecas-Caletrio, Jorge Rey-Martinez, Gabriel Trinidad-Ruiz, Eusebi Matiño-Soler, Santiago Santa Cruz-Ruiz, Angel Muñoz-Herrera, Nicolas Perez-Fernandez
OBJECTIVE: To evaluate vestibular compensation via measurement of the vestibulo-ocular reflex (VOR) following vestibular schwannoma surgery and its relationship with changes in saccades strategy after surgery. PATIENTS: Thirty-six consecutive patients with vestibular schwannomas, without brainstem compression, underwent surgical resection. Patients were recruited from University Hospital of Salamanca, Spain. METHODS: We assessed the age, sex, tumor size, degree of canalicular weakness, and preoperative video head impulse test (gain and saccade organization measured with PR score)...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28178036/can-the-video-head-impulse-test-define-severity-of-bilateral-vestibular-hypofunction
#5
Paul D Judge, Kristen L Janky, Kamran Barin
OBJECTIVE: The objective of the study was to compare rotary chair and video head impulse test (vHIT) findings in patients with bilateral vestibular hypofunction (BVH) to determine whether vHIT can: 1) define severity of BVH and 2) accurately predict rotary chair findings in patients with BVH. STUDY DESIGN: Retrospective chart review. SETTING: Research hospital. PATIENTS: Twenty subjects with bilateral vestibular hypofunction as assessed by rotary chair...
January 7, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28127679/motion-illusion-evidence-towards-human-vestibulo-thalamic-projections
#6
Aasef G Shaikh, Dominik Straumann, Antonella Palla
Contemporary studies speculated that cerebellar network responsible for motion perception projects to the cerebral cortex via vestibulo-thalamus. Here, we sought for the physiological properties of vestibulo-thalamic pathway responsible for the motion perception. Healthy subjects and the patient with focal vestibulo-thalamic lacunar stroke spun a hand-held rheostat to approximate the value of perceived angular velocity during whole-body passive earth-vertical axis rotations in yaw plane. Vestibulo-ocular reflex was simultaneously measured with high-resolution search coils (paradigm 1)...
January 27, 2017: Cerebellum
https://www.readbyqxmd.com/read/28115052/-temporary-loss-of-vestibular-function-after-cochlear-implant-surgery
#7
Leise Elisabeth Hviid Korsager, Jesper Hvass Schmidt, Christian Faber, Jens Højberg Wanscher
Loss of vestibular function is a common side effect to cochlear implant (CI) surgery. We present a patient who experienced balance problems and showed a reduced vestibulo-ocular reflex (VOR) gain (0.47 ± 0.10) combined with saccades in the horizontal semicircular canals demonstrated by the video head impulse test the day after CI surgery. One month after the operation VOR gain was normal (0.95 ± 0.05) and neither balance problems nor saccades occurred. Our findings indicate that vestibular dysfunction after CI surgery can be reversible, and VOR gain can return to normal...
January 23, 2017: Ugeskrift for Laeger
https://www.readbyqxmd.com/read/28103481/motor-learning-requires-purkinje-cell-synaptic-potentiation-through-activation-of-ampa-receptor-subunit-glua3
#8
Nicolas Gutierrez-Castellanos, Carla M Da Silva-Matos, Kuikui Zhou, Cathrin B Canto, Maria C Renner, Linda M C Koene, Ozgecan Ozyildirim, Rolf Sprengel, Helmut W Kessels, Chris I De Zeeuw
Accumulating evidence indicates that cerebellar long-term potentiation (LTP) is necessary for procedural learning. However, little is known about its underlying molecular mechanisms. Whereas AMPA receptor (AMPAR) subunit rules for synaptic plasticity have been extensively studied in relation to declarative learning, it is unclear whether these rules apply to cerebellum-dependent motor learning. Here we show that LTP at the parallel-fiber-to-Purkinje-cell synapse and adaptation of the vestibulo-ocular reflex depend not on GluA1- but on GluA3-containing AMPARs...
January 18, 2017: Neuron
https://www.readbyqxmd.com/read/28077670/the-mammalian-efferent-vestibular-system-plays-a-crucial-role-in-vestibulo-ocular-reflex-compensation-after-unilateral-labyrinthectomy
#9
Patrick P Hübner, Serajul I Khan, Americo A Migliaccio
The α9 nicotinic acetylcholine receptor (α9-nAChR) subunit is expressed in the vestibular and auditory periphery, and its loss of function could compromise peripheral input from the predominantly-cholinergic efferent vestibular system (EVS). A recent study has shown that α9-nAChRs play an important role in short-term vestibulo-ocular reflex (VOR) adaptation. We hypothesise that α9-nAChRs could also be important for other forms of vestibular plasticity, such as that needed for VOR recovery after vestibular organ injury...
January 11, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28077250/role-of-video-head-impulse-test-in-lateralization-of-vestibulopathy-comparative-study-with-caloric-test
#10
Pona Park, Joo Hyun Park, Ji Soo Kim, Ja-Won Koo
OBJECTIVE: To evaluate the lateralization value of video head-impulse test (vHIT) for the diagnosis of vestibulopathy and to analyze cases showing dissociated results with caloric test. METHODS: In total, 19 healthy volunteers and 92 dizzy patients who underwent both a caloric test and a vHIT were enrolled. Patients were divided into two groups depending on their fluctuating pattern of vertigo. The vestibulo-ocular reflex (VOR) gain and gain asymmetry (GA) of a vHIT as well as unilateral weakness (UW) and the sum of the slow-phase velocities (SPVs) of warm and cold irrigation of the same side were compared...
January 8, 2017: Auris, Nasus, Larynx
https://www.readbyqxmd.com/read/28063365/aging-reduces-the-high-frequency-and-short-term-adaptation-of-the-vestibulo-ocular-reflex-in-mice
#11
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/28054910/examining-effects-of-physical-exertion-on-the-dynamic-visual-acuity-test-in-collegiate-athletes
#12
Jessie N Patterson, Anna M Murphy, Julie A Honaker
BACKGROUND: Acute symptoms of dizziness and/or imbalance commonly experienced in athletes postconcussion are speculated to arise from dysfunction at multiple levels (i.e., inner ear or central vestibular system) to appropriately integrate afferent sensory information. Disruption along any pathway of the balance system can result in symptoms of dizziness, decreased postural control function (vestibulospinal reflex), and reduced vestibulo-ocular reflex function. This may also lead to decreased gaze stability with movements of the head and may account for symptoms of blurred vision or diplopia reported in almost half of athletes sustaining a concussion...
January 2017: Journal of the American Academy of Audiology
https://www.readbyqxmd.com/read/28045785/cold-thermal-irrigation-decreases-the-ipsilateral-gain-of-the-vestibulo-ocular-reflex
#13
Laszlo T Tamás, Konrad P Weber, Christopher J Bockisch, Dominik Straumann, David M Lasker, Béla Büki, Alexander A Tarnutzer
OBJECTIVES: During head rotations, neuronal firing rates increase in ipsilateral and decrease in contralateral vestibular afferents. At low accelerations, this "push-pull mechanism" is linear. At high accelerations, however, the change of firing rates is nonlinear in that the ipsilateral increase of firing rate is larger than the contralateral decrease. This mechanism of stronger ipsilateral excitation than contralateral inhibition during high-acceleration head rotation, known as Ewald's second law, is implemented within the nonlinear pathways...
December 27, 2016: Ear and Hearing
https://www.readbyqxmd.com/read/27942898/assessment-of-endolymphatic-hydrops-and-otolith-function-in-patients-with-m%C3%A3-ni%C3%A3-re-s-disease
#14
Tomoko Okumura, Takao Imai, Yasumitsu Takimoto, Noriaki Takeda, Tadashi Kitahara, Atsuhiko Uno, Takefumi Kamakura, Yasuhiro Osaki, Yoshiyuki Watanabe, Hidenori Inohara
Ménière's disease is associated with hydrops of the inner ear endolymphatic space, and histopathologically, the cochlea and vestibule are usually involved. We used gadolinium-enhanced magnetic resonance imaging and measured cervical and ocular vestibular evoked myogenic potentials and the gain in the utricular induced linear vestibulo-ocular reflex to test the hypothesis that vestibular hydrops in Ménière's disease patients is associated with otolith organ dysfunction. We evaluated 21 patients diagnosed with unilateral definitive Ménière's disease using gadolinium magnetic resonance imaging to detect endolymphatic hydrops in the cochlea and vestibule...
December 10, 2016: European Archives of Oto-rhino-laryngology
https://www.readbyqxmd.com/read/27926585/fluctuating-vestibulo-ocular-reflex-in-m%C3%A3-ni%C3%A3-re-s-disease
#15
Dario A Yacovino, Timothy C Hain, Maria Musazzi
OBJECTIVES: To describe the fluctuating high velocity vestibular ocular-reflex (VOR) during the Ménière's attacks and correlate those features with pathophysiology. PATIENTS: A patient with unilateral Ménière's disease (MD) was evaluated closely during and after acute vertigo episodes. MAIN OUTCOME MEASURES: The spontaneous nystagmus and the dynamic VOR changes were measured by the video head impulse test (VHIT) at different stages of the vertigo crisis and during the quiescent phase of the condition...
February 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/27898608/effect-of-spatial-orientation-of-the-horizontal-semicircular-canal-on-the-vestibulo-ocular-reflex
#16
Rebecca Maxwell, Constantin von Kirschbaum, Claudia Jerin, Nadine Lehnen, Eike Krause, Robert Gürkov
OBJECTIVE: To determine if an alignment of the horizontal semi-circular canal (hSCC) with the plane of rotation would enhance the vestibular-ocular reflex (VOR) gain result as it has been previously suggested. STUDY DESIGN: Comparative study of a physiological vestibular function test in healthy subjects. SETTING: Tertiary referral center for otology and neurotology. PATIENTS: Twenty two healthy volunteers were recruited for this study...
November 24, 2016: Otology & Neurotology
https://www.readbyqxmd.com/read/27877114/ontogenetic-development-of-vestibulo-ocular-reflexes-in-amphibians
#17
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/27814312/impact-of-artifacts-on-vor-gain-measures-by-video-oculography-in-the-acute-vestibular-syndrome
#18
Georgios Mantokoudis, Ali S Saber Tehrani, Amy Wozniak, Karin Eibenberger, Jorge C Kattah, Cynthia I Guede, David S Zee, David E Newman-Toker
OBJECTIVE: The video head impulse test (HIT) measures vestibular function (vestibulo-ocular reflex [VOR] gain - ratio of eye to head movement), and, in principle, could be used to make a distinction between central and peripheral causes of vertigo. However, VOG recordings contain artifacts, so using unfiltered device data might bias the final diagnosis, limiting application in frontline healthcare settings such as the emergency department (ED). We sought to assess whether unfiltered data (containing artifacts) from a video-oculography (VOG) device have an impact on VOR gain measures in acute vestibular syndrome (AVS)...
November 3, 2016: Journal of Vestibular Research: Equilibrium & Orientation
https://www.readbyqxmd.com/read/27805050/modeled-changes-of-cerebellar-activity-in-mutant-mice-are-predictive-of-their-learning-impairments
#19
Aleksandra Badura, Claudia Clopath, Martijn Schonewille, Chris I De Zeeuw
Translating neuronal activity to measurable behavioral changes has been a long-standing goal of systems neuroscience. Recently, we have developed a model of phase-reversal learning of the vestibulo-ocular reflex, a well-established, cerebellar-dependent task. The model, comprising both the cerebellar cortex and vestibular nuclei, reproduces behavioral data and accounts for the changes in neural activity during learning in wild type mice. Here, we used our model to predict Purkinje cell spiking as well as behavior before and after learning of five different lines of mutant mice with distinct cell-specific alterations of the cerebellar cortical circuitry...
November 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27777829/non-invasive-neuromodulation-using-time-varying-caloric-vestibular-stimulation
#20
Robert D Black, Lesco L Rogers, Kristen K Ade, Heather A Nicoletto, Heather D Adkins, Daniel T Laskowitz
Caloric vestibular stimulation (CVS) to elicit the vestibulo-ocular reflex has long been used in clinical settings to aid in the diagnosis of balance disorders and to confirm the absence of brainstem function. While a number of studies have hinted at the potential therapeutic applications of CVS, the limitations of existing devices have frustrated that potential. Current CVS irrigators use water or air during short-duration applications; however, this approach is not tenable for longer duration therapeutic protocols or home use...
2016: IEEE Journal of Translational Engineering in Health and Medicine
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