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Vestibulo ocular reflex

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https://www.readbyqxmd.com/read/28439720/the-impact-of-oral-promethazine-on-human-whole-body-motion-perceptual-thresholds
#1
Ana Diaz-Artiles, Adrian J Priesol, Torin K Clark, David P Sherwood, Charles M Oman, Laurence R Young, Faisal Karmali
Despite the widespread treatment of motion sickness symptoms using drugs and the involvement of the vestibular system in motion sickness, little is known about the effects of anti-motion sickness drugs on vestibular perception. In particular, the impact of oral promethazine, widely used for treating motion sickness, on vestibular perceptual thresholds has not previously been quantified. We examined whether promethazine (25 mg) alters vestibular perceptual thresholds in a counterbalanced, double-blind, within-subject study...
April 24, 2017: Journal of the Association for Research in Otolaryngology: JARO
https://www.readbyqxmd.com/read/28436631/-video-head-impulse-test-for-evaluation-of-vestibular-function-in-patients-with-vestibular-neuritis-and-benign-paroxysmal-positional-vertigo
#2
Qiongfeng Guan, Lisan Zhang, Wenke Hong, Yi Yang, Zhaoying Chen, Dan Zhang, Xingyue Hu
Objective: To assess the clinical application of video head impulse test (vHIT) for vestibular function in vestibular neuritis (VN) and benign paroxysmal positional vertigo (BPPV) patients. Methods: Thirty-three patients with VN and 43 patients with BPPV were enrolled from Sir Run Run Shaw Hospital and Ningbo Second Hospital from March 15 to September 10, 2015; and 50 healthy controls were also enrolled in the study. vHIT was used to quantitatively test the vestibulo-ocular reflex (VOR) gains of a pair of horizontal semicircular canals...
January 25, 2017: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
https://www.readbyqxmd.com/read/28434022/effects-of-vestibular-disorders-on-vestibular-reflex-and-imagery
#3
B S Cohen, J Provasi, P Leboucher, I Israël
The aim of this study was to establish the effect of vestibular lesion on vestibular imagery. Subjects were required to estimate verbally their passively travelled rotation angles in complete darkness, i.e., to activate vestibular imagery. During motion, the vestibulo-ocular reflex (VOR) was measured. Thus, we examined the coherence between the vestibulo-ocular reflex and self-rotation imagery, with vestibular-lesioned patients and healthy participants. Unilateral acute and chronic patients, bilateral patients, and healthy subjects were compared...
April 22, 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
https://www.readbyqxmd.com/read/28431905/dynamic-interhemispheric-competition-and-vestibulo-cortical-control-in-humans-a-theoretical-proposition
#4
REVIEW
Qadeer Arshad
Neuroscientific research has made a concerted effort to determine cortical localisation using various functional imaging techniques. This approach has undoubtedly yielded important novel anatomical knowledge, albeit at times contradictory, regarding the structural organisation of the vestibular cortex. Unfortunately however, this knowledge has not translated to our understanding regarding how neural mechanisms control vestibular function. Based upon recent functional imaging, lesion and neuro-physiological data that has demonstrated (i) the close behavioural and neuro-anatomical relationship between cortical processing of vestibular and spatial attention signals, and (ii) that inducing interhemispheric competition can in-turn strongly modulate vestibular function akin to that observed in cortical lesion patients, I herewith propose the hypothesis that vestibular cortical processing is controlled, as per for spatial attention, via dynamic interhemispheric competition...
April 18, 2017: Neuroscience
https://www.readbyqxmd.com/read/28410279/ocular-motor-manifestations-of-multiple-sclerosis
#5
Elodie Nerrant, Caroline Tilikete
BACKGROUND: Multiple sclerosis (MS) is a demyelinating disease of the central nervous system leading to disability, especially in young patients. Acute or chronic lesions of MS within the brainstem and the cerebellum frequently result in ocular motor disorders. EVIDENCE ACQUISITION: This review encompasses the spectrum of ocular motor disorders in patients with MS emphasizing prevalence, examination findings, diagnostic features, functional consequences, classification of MS course, and management of these disturbances of ocular motility...
April 13, 2017: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
https://www.readbyqxmd.com/read/28404827/new-insights-into-vestibular-saccade-interaction-based-on-covert-corrective-saccades-in-patients-with-unilateral-vestibular-deficits
#6
Paolo Colagiorgio, Maurizio Versino, Silvia Colnaghi, Silvia Quaglieri, Marco Manfrin, Ewa Zamaro, Georgios Mantokoudis, David S Zee, Stefano Ramat
In response to passive high-acceleration head impulses patients with low vestibulo-ocular reflex (VOR) gains often produce covert (executed while the head is still moving) corrective saccades in the direction of deficient slow phases. Here we examined 23 patients using passive, and nine also active, head impulses with acute (< 10 days from onset) unilateral vestibular neuritis and low VOR gains. We found that when corrective saccades are larger than 10°, the slow-phase component of the VOR is inhibited, even though inhibition increases further the time to reacquire the fixation target...
April 12, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28393118/postural-compensation-strategy-depends-on-the-severity-of-vestibular-damage
#7
Lara A Thompson, Csilla Haburcakova, Richard F Lewis
The purpose of this study was to investigate the effects of various levels of vestibular function on balance in two, free-standing rhesus monkeys. We hypothesized that postural control strategy depended on the severity of vestibular damage. More specifically, that increased muscle stiffness (via short-latency mechanisms) was adequate to compensate for mild damage, but long-latency mechanisms must be utilized for more severe vestibular damage. One animal was studied for pre-ablated and mild vestibular dysfunction states, while a second animal was studied in a pre-ablated and severe vestibular dysfunction state...
March 2017: Heliyon
https://www.readbyqxmd.com/read/28387690/the-vestibular-implant-a-probe-in-orbit-around-the-human-balance-system
#8
Angelica Perez Fornos, Samuel Cavuscens, Maurizio Ranieri, Raymond van de Berg, Robert Stokroos, Herman Kingma, Jean-Philippe Guyot, Nils Guinand
The primary goal of the vestibular implant is to restore the vestibular function in patients with a disabling bilateral vestibular loss for whom there is currently no available treatment. The prototype developed by our team is a hybrid system consisting of a modified cochlear implant incorporating additional vestibular electrodes. Therefore, in addition of delivering sound information it is also capable of delivering motion information to the central nervous system using electrical stimulation. To date, thirteen patients have been implanted with such vestibular implant prototypes...
2017: Journal of Vestibular Research: Equilibrium & Orientation
https://www.readbyqxmd.com/read/28380076/strength-of-baseline-inter-trial-correlations-forecasts-adaptive-capacity-in-the-vestibulo-ocular-reflex
#9
Kara H Beaton, Aaron L Wong, Steven B Lowen, Mark Shelhamer
Individual differences in sensorimotor adaptability may permit customized training protocols for optimum learning. Here, we sought to forecast individual adaptive capabilities in the vestibulo-ocular reflex (VOR). Subjects performed 400 head-rotation steps (400 trials) during a baseline test, followed by 20 min of VOR gain adaptation. All subjects exhibited mean baseline VOR gain of approximately 1.0, variable from trial to trial, and showed desired reductions in gain following adaptation with variation in extent across individuals...
2017: PloS One
https://www.readbyqxmd.com/read/28365885/the-spectrum-of-vestibular-and-ocular-motor-abnormalities-in-thiamine-deficiency
#10
REVIEW
Jorge C Kattah
PURPOSE: The first aim of this review is to summarize recent ocular motor signs in pre-encephalopathy patients with nutritional deficiency at risk of thiamine deficiency. Timely recognition of thiamine depletion in these patients, who may have a normal brain MRI, could lead to appropriate management and prevention of Wernicke's encephalopathy (WE) with full recovery. The second aim is to incorporate recent diagnostic testing on the revised WE diagnostic criteria and the identification of patients who may show slow, partial, or no response to treatment...
May 2017: Current Neurology and Neuroscience Reports
https://www.readbyqxmd.com/read/28361069/posterior-reversible-encephalopathy-syndrome-associated-with-left-horizontal-gaze-palsy
#11
Amer Hawatmeh, Sarah Studyvin, Moh'd Al-Halawani, Sawsan Amireh, Mohammad Thawabi
Posterior reversible encephalopathy syndrome (PRES) is characterized by rapid onset of symptoms including headache, seizures, altered consciousness, and visual disturbance, as well as radiologic findings of focal reversible vasogenic edema. Multiple visual disturbances have been described in PRES, such as hemianopia, visual neglect, auras, visual hallucinations, and cortical blindness. However, horizontal gaze palsy has not been previously reported. We report a 72-year-old female who presented with blurred vision, severe headache, lethargy, and later developed seizures...
March 2017: Annals of Translational Medicine
https://www.readbyqxmd.com/read/28352247/refixation-saccades-with-normal-gain-values-a-diagnostic-problem-in-the-video-head-impulse-test-a-case-report
#12
Leise Elisabeth Hviid Korsager, Christian Emil Faber, Jesper Hvass Schmidt, Jens Højberg Wanscher
Refixation saccades with normal gain value occur more frequently with increasing age. The phenomenon has also been observed in different vestibular disorders. In this case, we present a young male with normal gain value and refixation saccades tested with the video head impulse test (vHIT) the day after his cochlear implantation. One month after surgery, refixation saccades were no longer present. This suggests that refixation saccades can occur as a result of temporary pathology such as surgery. Refixation saccades with normal gain values might reflect a partial deficit in the vestibulo-ocular reflex...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28344549/functional-brain-activation-in-response-to-a-clinical-vestibular-test-correlates-with-balance
#13
Fatemeh Noohi, Catherine Kinnaird, Yiri DeDios, Igor S Kofman, Scott Wood, Jacob Bloomberg, Ajitkumar Mulavara, Rachael Seidler
The current study characterizes brain fMRI activation in response to two modes of vestibular stimulation: Skull tap and auditory tone burst. The auditory tone burst has been used in previous studies to elicit either a vestibulo-spinal reflex [saccular-mediated colic Vestibular Evoked Myogenic Potentials (cVEMP)], or an ocular muscle response [utricle-mediated ocular VEMP (oVEMP)]. Research suggests that the skull tap elicits both saccular and utricle-mediated VEMPs, while being faster and less irritating for subjects than the high decibel tones required to elicit VEMPs...
2017: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/28336357/assessment-of-vestibulo-ocular-function-without-measuring-eye-movements
#14
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
#15
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: Musculoskeletal Science & Practice
https://www.readbyqxmd.com/read/28318060/integrating-postural-and-vestibular-dimensions-to-depict-impairment-in-moderate-to-severe-obstructive-sleep-apnea-syndrome-patients
#16
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
#17
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
#18
Haike Dietrich, Stefan Glasauer, Hans Straka
Vestibulo-ocular reflexes (VORs) 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 visuovestibular 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...
April 12, 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
#19
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
#20
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
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