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Vestibulo ocular reflex

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https://www.readbyqxmd.com/read/28515977/establishing-normative-change-values-in-visual-acuity-loss-during-the-dynamic-visual-acuity-test
#1
Chris Marquez, Monica Lininger, Scot Raab
BACKGROUND: Baseline visual acuity (VA) loss from static to dynamic head conditions assessed using the Dynamic Visual Acuity Testing (DVAT) have not been established in NCAA football players. DVAT assesses the Vestibulo-Ocular Reflex (VOR) which is measured in Logarithm of the Minimum Angle of Resolution (logMAR). Decreased VA beyond baseline measures may detect VOR impairment and impact treatment protocols and assist in return to play decisions post-concussion. HYPOTHESIS/PURPOSE: To establish normative VA mean scores during a static head posture as well as dynamically during the DVAT with a head speed of 150 deg/s in the pitch (vertical) and yaw (horizontal) planes rotating 20 degrees in each direction...
April 2017: International Journal of Sports Physical Therapy
https://www.readbyqxmd.com/read/28515458/floccular-fossa-size-is-not-a-reliable-proxy-of-ecology-and-behaviour-in-vertebrates
#2
S Ferreira-Cardoso, R Araújo, N E Martins, G G Martins, S Walsh, R M S Martins, N Kardjilov, I Manke, A Hilger, R Castanhinha
The cerebellar floccular and parafloccular lobes are housed in fossae of the periotic region of the skull of different vertebrates. Experimental evidence indicates that the lobes integrate visual and vestibular information and control the vestibulo-ocular reflex, vestibulo-collic reflex, smooth pursuit and gaze holding. Multiple paleoneuroanatomy studies have deduced the behaviour of fossil vertebrates by measuring the floccular fossae (FF). These studies assumed that there are correlations between FF volume and behaviour...
May 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28496432/vestibular-loss-in-older-adults-is-associated-with-impaired-spatial-navigation-data-from-the-triangle-completion-task
#3
Yanjun Xie, Robin T Bigelow, Scott F Frankenthaler, Stephanie A Studenski, Scott D Moffat, Yuri Agrawal
BACKGROUND: Vestibular inputs have been shown to play a critical role in spatial navigation. In this study, we sought to evaluate whether vestibular loss due to aging contributes to impaired spatial navigation as measured by the triangle completion task (TCT). MATERIALS AND METHODS: We recruited three types of participants: young controls <55 years of age, older controls ≥55 years of age, and older patients from a Neurotology Clinic with evidence of vestibular physiologic impairment but who did not have any known vestibular disorder...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28491901/predictors-of-clinical-recovery-from-vestibular-neuritis-a-prospective-study
#4
Sian Cousins, Diego Kaski, Nicholas Cutfield, Qadeer Arshad, Hena Ahmad, Michael A Gresty, Barry M Seemungal, John Golding, Adolfo M Bronstein
We sought to identify predictors of symptomatic recovery in vestibular neuritis. Forty VN patients were prospectively studied in the acute phase (median = 2 days) and 32 in the recovery phase (median = 10 weeks) with vestibulo-ocular reflex, vestibular-perceptual, and visual dependence tests and psychological questionnaires. Clinical outcome was Dizziness Handicap Inventory score at recovery phase. Acute visual dependency and autonomic arousal predicted outcome. Worse recovery was associated with a combination of increased visual dependence, autonomic arousal, anxiety/depression, and fear of bodily sensations, but not with vestibular variables...
May 2017: Annals of Clinical and Translational Neurology
https://www.readbyqxmd.com/read/28486231/decrease-of-horizontal-canal-vestibulo-oculomotor-reflex-gain-in-the-elderly-with-dysequilibrium-without-lifetime-vertigo
#5
Roberto Teggi, Matteo Trimarchi, Omar Gatti, Francesco Fornasari, Mario Bussi
BACKGROUND/AIMS: Unsteadiness in the elderly is a frequent complaint and a strong predictor of falls and psychological distress. Although there is a general consensus that it is a multifactorial condition, recent studies have focused on the role of aging of the vestibular system as a possible cofactor. The aim of our work was to assess horizontal canal function in the elderly. METHODS: We evaluated the gain of horizontal vestibulo-ocular reflex (VOR) with a video head impulse test on a sample of 58 subjects aged >70 years without lifetime episodes of vertigo and correlated the value with different clinical conditions (hypertension, diabetes, prior cardiovascular and vascular disorders of the central nervous system, and falls)...
May 10, 2017: ORL; Journal for Oto-rhino-laryngology and its related Specialties
https://www.readbyqxmd.com/read/28484420/ocular-tremor-in-parkinson-s-disease-discussion-debate-and-controversy
#6
REVIEW
Diego Kaski, Adolfo M Bronstein
The identification of ocular tremor in a small cohort of patients with Parkinson's disease (PD) had lay somewhat dormant until the recent report of a pervasive ocular tremor as a universal finding in a large PD cohort that was, however, generally absent from a cohort of age-matched healthy subjects. The reported tremor had frequency characteristics similar to those of PD limb tremor, but the amplitude and frequency of the tremor did not correlate with clinical tremor ratings. Much controversy ensued as to the origin of such a tremor, and specifically as to whether a pervasive ocular tremor was a fundamental feature of PD, or rather a compensatory eye oscillation secondary to a transmitted head tremor, and thus a measure of a normal vestibulo-ocular reflex...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28477092/-intracochlear-schwannoma-tumor-removal-via-subtotal-cochleostomy-and-partial-cochlear-reconstruction-with-preservation-of-semicircular-canal-function-german-version
#7
S Plontke, S Kösling, N Pazaitis, T Rahne
We report about a patient who in 2005, aged 37 years, experienced 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) contrast-enhancing lesion in the second turn of the right cochlea. 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 via transmeatal subtotal cochleostomy...
May 5, 2017: HNO
https://www.readbyqxmd.com/read/28457586/adaptation-of-the-vertical-vestibulo-ocular-reflex-in-cats-during-low-frequency-vertical-rotation
#8
Hiroaki Fushiki, Motoyoshi Maruyama, Hideo Shojaku
OBJECTIVE: We examined plastic changes in the vestibulo-ocular reflex (VOR) during low-frequency vertical head rotation, a condition under which otolith inputs from the vestibular system are essential for VOR generation. METHODS: For adaptive conditioning of the vertical VOR, 0.02Hz sinusoidal pitch rotation for one hour about the earth's horizontal axis was synchronized with out-of-phase vertical visual stimulation from a random dot pattern. RESULTS: A vertical VOR was well evoked when the upright animal rotated around the earth-horizontal axis (EHA) at low frequency due to the changing gravity stimulus and dynamic stimulation of the otoliths...
April 27, 2017: Auris, Nasus, Larynx
https://www.readbyqxmd.com/read/28444617/computational-theory-underlying-acute-vestibulo-ocular-reflex-motor-learning-with-cerebellar-long-term-depression-and-long-term-potentiation
#9
Keiichiro Inagaki, Yutaka Hirata
The vestibulo-ocular reflex (VOR) can be viewed as an adaptive control system that maintains compensatory eye movements during head motion. As the cerebellar flocculus is intimately involved in this adaptive motor control of the VOR, the VOR has been a popular model system for investigating cerebellar motor learning. Long-term depression (LTD) and long-term potentiation (LTP) at the parallel fiber-Purkinje cell synapses are considered to play major roles in cerebellar motor learning. A recent study using mutant mice demonstrated cerebellar motor learning with hampered LTD; the study concluded that the parallel fiber-Purkinje cell LTD is not essential...
April 25, 2017: Cerebellum
https://www.readbyqxmd.com/read/28439720/the-impact-of-oral-promethazine-on-human-whole-body-motion-perceptual-thresholds
#10
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
#11
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
#12
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
#13
REVIEW
Qadeer Arshad
Neuroscientific research has made a concerted effort to determine cortical localization using various functional imaging techniques. This approach has undoubtedly yielded important novel anatomical knowledge, albeit at times contradictory, regarding the structural organization 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 have demonstrated (i) the close behavioral 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 19, 2017: Neuroscience
https://www.readbyqxmd.com/read/28410279/ocular-motor-manifestations-of-multiple-sclerosis
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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