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Vestibulo ocular reflex

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https://www.readbyqxmd.com/read/28336357/assessment-of-vestibulo-ocular-function-without-measuring-eye-movements
#1
Kara H Beaton, Michael Schubert, Mark Shelhamer
BACKGROUND: The vestibulo-ocular reflex (VOR) maintains stable gaze during head motion. Deficiencies lead to apparent world motion due to incomplete stabilization of eyes in space. VOR measurement requires specialized apparatus, trained operators, and significant setup time. NEW METHOD: We present a system (VON: vestibulo-ocular nulling) for rapid vestibulo-ocular assessment without measuring eye movements per se. VON uses a head-mounted motion sensor, laptop computer with user input control, and laser target whose position is controlled by the computer...
March 20, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28324698/eye-stabilization-reflexes-in-traumatic-and-non-traumatic-chronic-neck-pain-patients
#2
Britta K Ischebeck, Jurryt de Vries, Malou Janssen, Jan Paul van Wingerden, Gert-Jan Kleinrensink, Jos N van der Geest, Maarten A Frens
BACKGROUND: Many chronic neck pain patients experience problems with vision. These problems are possibly induced by deviations of the eye stabilization reflexes. It is not known whether these eye reflex alterations occur both in traumatic and non-traumatic neck pain patients. OBJECTIVE: To investigate if the cervico-ocular reflex (COR) and the vestibulo-ocular reflex (VOR) are changed in tertiary care patients with prolonged, chronic neck pain with various origin of complaints...
March 16, 2017: Musculoskelet Sci Pract
https://www.readbyqxmd.com/read/28318060/integrating-postural-and-vestibular-dimensions-to-depict-impairment-in-moderate-to-severe-obstructive-sleep-apnea-syndrome-patients
#3
Alessandro Micarelli, Claudio Liguori, Andrea Viziano, Francesca Izzi, Fabio Placidi, Marco Alessandrini
Vestibular dysfunction was linked to moderate-to-severe obstructive sleep apnea syndrome (OSAS) patients in literature. However, due to a lack of knowledge among valid and recent implementations conceived to study postural control on static posturography (SP) and vestibulo-ocular reflex (VOR) gain under physiological conditions (video Head Impulse Test; vHIT), the aim of this work was to integrate (i) VOR changes via vHIT implementation, (ii) postural arrangement by studying both classical parameters and frequency spectra (PS) and (iii) correlation between these findings, polygraphic (PG) and subjective scores along Dizziness Handicap Inventory (DHI) and Epworth Sleepiness Scale (ESS)...
March 20, 2017: Journal of Sleep Research
https://www.readbyqxmd.com/read/28303261/long-lasting-visuo-vestibular-mismatch-in-freely-behaving-mice-reduces-the-vestibulo-ocular-reflex-and-leads-to-neural-changes-in-the-direct-vestibular-pathway
#4
Julie Carcaud, Filipa França de Barros, Erwin Idoux, Daniel Eugène, Lionel Reveret, Lee E Moore, Pierre-Paul Vidal, Mathieu Beraneck
Calibration of the vestibulo-ocular reflex (VOR) depends on the presence of visual feedback. However, the cellular mechanisms associated with VOR modifications at the level of the brainstem remain largely unknown. A new protocol was designed to expose freely behaving mice to a visuo-vestibular mismatch during a 2-week period. This protocol induced a 50% reduction of the VOR. In vivo pharmacological experiments demonstrated that the VOR reduction depends on changes located outside the flocculus/paraflocculus complex...
January 2017: ENeuro
https://www.readbyqxmd.com/read/28292832/functional-organization-of-vestibulo-ocular-responses-in-abducens-motoneurons
#5
Haike Dietrich, Stefan Glasauer, Hans Straka
Vestibulo-ocular reflexes (VOR) are the dominating contributors to gaze stabilization in all vertebrates. During horizontal head movements, abducens motoneurons form the final element of the reflex arc that integrates visuo-vestibular inputs into temporally precise motor commands for the lateral rectus eye muscle. Here, we studied a possible differentiation of abducens motoneurons into subtypes by evaluating their morphology, discharge properties and synaptic pharmacology in semi-intact in vitro preparations of larval Xenopus laevis Extracellular nerve recordings during sinusoidal head motion revealed a continuum of resting rates and activation thresholds during vestibular stimulation...
March 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28271408/moving-or-being-moved-that-makes-a-difference
#6
Hans Straka, Boris P Chagnaud
During head/body movements, gaze stability is ensured by transformation of motion-related sensory signals into respective motor commands. Passively induced motion in all vertebrates including amphibians evokes a robust vestibulo-ocular reflex, suggesting an equally important role of this motor reaction during actively induced motion. However, during self-induced movements including locomotion, motor efference copies offer a convenient additional substrate for counteracting retinal image displacements. During such locomotor activity in Xenopus laevis tadpoles, spinal central pattern generator-derived efference copies elicit spatio-temporally specific eye movements, which are functionally appropriate to offset swimming-related retinal image displacements...
March 7, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28265260/role-of-the-patient-s-history-of-vestibular-symptoms-in-the-clinical-evaluation-of-the-bedside-head-impulse-test
#7
Christoph Helmchen, Julia Knauss, Peter Trillenberg, Anita Frendl, Andreas Sprenger
OBJECTIVE: Our aim was to identify the role of the investigators' knowledge of the patient's history of vestibular symptoms (PVH) in the clinical evaluation of the bedside head-impulse test (bHIT). We hypothesized that this knowledge will reduce uncertainty and improve bHIT accuracy when compared to quantitative analysis of the vestibulo-ocular reflex by video head-impulse test (vHIT). METHODS: We looked for changes in the clinical assessment of the bHIT in 594 consecutive patients before and after taking PVH...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28242733/ocular-stability-and-set-point-adaptation
#8
REVIEW
D S Zee, P Jareonsettasin, R J Leigh
A fundamental challenge to the brain is how to prevent intrusive movements when quiet is needed. Unwanted limb movements such as tremor impair fine motor control and unwanted eye drifts such as nystagmus impair vision. A stable platform is also necessary to launch accurate movements. Accordingly, nature has designed control systems with agonist (excitation) and antagonist (inhibition) muscle pairs functioning in push-pull, around a steady level of balanced tonic activity, the set-point Sensory information can be organized similarly, as in the vestibulo-ocular reflex, which generates eye movements that compensate for head movements...
April 19, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28224454/effects-of-sustained-otolith-only-stimulation-on-post-rotational-nystagmus
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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