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gaze stabilization

Neil M Thomas, Theodoros M Bampouras, Tim Donovan, Susan Dewhurst
Visual information is used for postural stabilization in humans. However, little is known about how eye movements prevalent in everyday life interact with the postural control system in older individuals. Therefore, the present study assessed the effects of stationary gaze fixations, smooth pursuits, and saccadic eye movements, with combinations of absent, fixed and oscillating large-field visual backgrounds to generate different forms of retinal flow, on postural control in healthy young and older females...
2016: Frontiers in Aging Neuroscience
Shin C Beh, Teresa C Frohman, Elliot M Frohman
BACKGROUND: The cerebellum plays a central role in the online, real-time control, and long-term modulation of eye movements. EVIDENCE ACQUISITION: We reviewed the latest (fifth) edition of Leigh and Zee's textbook, The Neurology of Eye Movements, and literature in PUBMED using the following terms: cerebellum, flocculus, paraflocculus, vermis, oculomotor vermis, dorsal vermis, caudal fastigial nucleus, fastigial oculomotor region, uvula, nodulus, ansiform lobule, eye movements, saccades, ipsipulsion, contrapulsion, smooth pursuit, vergence, convergence, divergence, gaze-holding, down beat nystagmus, vestibulo-ocular reflex (VOR), angular VOR, translational VOR, skew deviation, velocity storage...
September 16, 2016: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
Maciej Perdziak, Dagmara K Witkowska, Wojciech Gryncewicz, Jan K Ober
Amblyopia is a developmental disorder of vision usually associated with the presence of strabismus and/or anisometropia during early childhood. Subject literature has shown that both the amblyopic and fellow eyes (especially in strabismic subjects) may manifest a variety of perceptual and oculomotor deficits. Previous studies using simple saccadic responses (pro-saccades) showed an increased saccadic latency only for the amblyopic eye viewing conditions. So far, there have appeared no saccadic latency studies in strabismic amblyopia for more complex volitional saccades...
August 1, 2016: Journal of Vision
Roeland B van Leeuwen, Bart W Smits, Richard J Rodenburg, Baziel G van Engelen
In patients with a triad of sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (SANDO), the presenting features are mainly ataxia or ptosis. SANDO patients often have impaired balance and gait, which is not surprising considering the combination of sensory ataxic neuropathy, and additional symptoms like cerebellar ataxia and limb girdle weakness. We describe a SANDO patient who noticed an increasingly impaired balance and gait, without any dizziness. Neurological investigation revealed an external ophthalmeplegia and a cerebellar ataxia; the head impulse test was not reliable because of eye movement disorders...
September 2016: Journal of Clinical Neuromuscular Disease
Bianca Huurneman, F Nienke Boonstra, Jeroen Goossens
PURPOSE: To determine changes in oculomotor behavior after 10 sessions of perceptual learning on a letter discrimination task in children with infantile nystagmus (IN). METHODS: Children with IN (18 children with idiopathic IN and 18 with oculocutaneous albinism accompanied by IN) aged 6 to 11 years were divided into two training groups matched on diagnosis: an uncrowded training group (n = 18) and a crowded training group (n = 18). Target letters always appeared briefly (500 ms) at an eccentric location, forcing subjects to quickly redirect their gaze...
August 1, 2016: Investigative Ophthalmology & Visual Science
Jumana Khan, Sian Gaze, Stephen Tomlin
AIM: To explore what involvement pharmacists in the UK have in paediatric palliative care OBJECTIVES: 1. To determine the current roles and services provided by pharmacists to paediatric palliative care patients.2. To establish how other members of the multidisciplinary team perceive the pharmacist's role and the extent to which they value the pharmacist's contributions.3. To identify the references used by the multidisciplinary team to make clinical decisions about medication use in paediatric palliative care patients...
September 2016: Archives of Disease in Childhood
Dorte Ancher Larsen, Toke Bek
PURPOSE: Fixational eye movements are necessary for maintaining normal vision by preventing a stabilized image on the retina that would result in visual fading. The movements can be divided into tremor, drifts and saccades that may be related to movements of gaze and to fixation. It has previously been shown that the frequency of fixational saccades with an amplitude larger than 3° depends on age. The purpose of this study was to investigate whether other parameters describing fixational saccades also depend on age which necessitates age correction in studies of fixation during visual development...
August 18, 2016: Acta Ophthalmologica
Nancy L Low Choy, Mary-Therese M Lucey, Susan L Lewandowski, Benedict J Panizza
OBJECTIVES/HYPOTHESIS: To investigate balance, community mobility, gaze instability, and dizziness handicap and assess falls risk in people who are conservatively managed with small vestibular schwannoma (VS). STUDY DESIGN: Cross-sectional study with controls. METHODS: The study involved 18 people (mean age 58.7 ± 12.2 years) diagnosed with VS (<12 mm) and 22 age-matched controls (mean age 56.9 ± 8.0 years). Measures included standing on firm and foam surfaces with feet apart, then together with eyes open and closed, Timed Up and Go (TUG) test and dual TUG test, Dynamic Gait Index, 6-Minute Walk Test, Halmagyi Impulse Test, Dynamic Visual Acuity Test, and the Dizziness Handicap Inventory...
August 13, 2016: Laryngoscope
Sérgio T Rodrigues, Paula F Polastri, Gisele C Gotardi, Stefane A Aguiar, Marcelo R Mesaros, Mayara B Pestana, Fabio A Barbieri
Cascade ball juggling is a complex perceptual motor skill which requires efficient postural stabilization. The aim of this study was to investigate effects of experience (expert and intermediate groups) and foot distance (wide and narrow stances) on body sway of jugglers during three ball cascade juggling. A total of 10 expert jugglers and 11 intermediate jugglers participated in this study. Participants stood barefoot on the force plate (some participants wore a gaze tracking system), with feet maintained in wide and narrow conditions and performed three 40-seconds trials of the three-ball juggling task...
August 2016: Perceptual and Motor Skills
Eric R Anson, Robin T Bigelow, John P Carey, Quan-Li Xue, Stephanie Studenski, Michael C Schubert, Konrad P Weber, Yuri Agrawal
OBJECTIVE: Rotational vestibular function declines with age resulting in saccades as a compensatory mechanism to improve impaired gaze stability. Small reductions in rotational vestibulo-ocular reflex (VOR) gain that would be considered clinically normal have been associated with compensatory saccades. We evaluated whether compensatory saccade characteristics varied as a function of age, independent of semicircular canal function as quantified by VOR gain. METHODS: Horizontal VOR gain was measured in 243 participants age 27-93 from the Baltimore Longitudinal Study of Aging using video head impulse testing...
2016: Frontiers in Neurology
Josephine Barbaro, Cheryl Dissanayake
Autism spectrum disorder diagnoses in toddlers have been established as accurate and stable across time in high-risk siblings and clinic-referred samples. Few studies have investigated diagnostic stability in children prospective identified in community-based settings. Furthermore, there is a dearth of evidence on the individual behaviours that predict diagnostic change over time. The stability and change of autism spectrum disorder diagnoses were investigated from 24 to 48 months in 77 children drawn from the Social Attention and Communication Study...
July 28, 2016: Autism: the International Journal of Research and Practice
Lovro Suhodolčan, Marko Mihelak, Janez Brecelj, Rok Vengust
We describe a case of a 19-year-old young man with oligoarthritis type of juvenile idiopathic arthritis, who presented with several month duration of lower neck pain and progressive muscular weakness of all four limbs. X-rays of the cervical spine demonstrated spontaneous apophyseal joint fusion from the occipital condyle to C6 and from C7 to Th2 with marked instability between C6 and C7. Surgical intervention began with anterolateral approach to the cervical spine performing decompression, insertion of cage and anterior vertebral plate and screws, followed by posterior approach and fixation...
July 18, 2016: World Journal of Orthopedics
Seyyed Amir Hossein Ghazizadeh Hashemi, Sadegh Jafarzadeh, Majid Haddadi Aval, Reza Hosseinabadi
INTRODUCTION: Patients with bilateral weakness (BW) have many difficulties in gaze stability that interfere with their normal function. The aim of this study was to evaluate ocular motor functions in patients with BW to better understand the problem of gaze instability in these patients. MATERIALS AND METHODS: Patients were referred from the Otolaryngology Department for Vestibular Assessment to our clinic between November 2014 and March 2015. We assessed ocular motor function (gaze, saccade, and smooth pursuit) in patients over the age of 18 years with BW, as verified by a caloric test...
May 2016: Iranian Journal of Otorhinolaryngology
Ilse M Daly, Martin J How, Julian C Partridge, Shelby E Temple, N Justin Marshall, Thomas W Cronin, Nicholas W Roberts
Gaze stabilization is an almost ubiquitous animal behaviour, one that is required to see the world clearly and without blur. Stomatopods, however, only fix their eyes on scenes or objects of interest occasionally. Almost uniquely among animals they explore their visual environment with a series pitch, yaw and torsional (roll) rotations of their eyes, where each eye may also move largely independently of the other. In this work, we demonstrate that the torsional rotations are used to actively enhance their ability to see the polarization of light...
2016: Nature Communications
Callum David Mole, Georgios Kountouriotis, Jac Billington, Richard McGilchrist Wilkie
Responding to changes in the road ahead is essential for successful driving. Steering control can be modeled using 2 complementary mechanisms: guidance control (to anticipate future steering requirements) and compensatory control (to stabilize position-in-lane). Drivers seem to rapidly sample the visual information needed for steering using active gaze patterns, but the way in which this perceptual information is combined remains unclear. Influential models of steering capture many steering behaviors using just 'far' and 'near' road regions to inform guidance and compensatory control respectively (Salvucci & Gray, 2004)...
July 11, 2016: Journal of Experimental Psychology. Human Perception and Performance
Jianliang Tong, Jun Maruta, Kristin J Heaton, Alexis L Maule, Umesh Rajashekar, Lisa A Spielman, Jamshid Ghajar
To aid a clear and unified visual perception while tracking a moving target, both eyes must be coordinated, so the image of the target falls on approximately corresponding areas of the fovea of each eye. The movements of the two eyes are decoupled during sleep, suggesting a role of arousal in regulating binocular coordination. While the absence of visual input during sleep may also contribute to binocular decoupling, sleepiness is a state of reduced arousal that still allows for visual input, providing a context within which the role of arousal in binocular coordination can be studied...
2016: Frontiers in Neurology
Michael A Busa, Jongil Lim, Richard E A van Emmerik, Joseph Hamill
Individuals regulate the transmission of shock to the head during running at different stride frequencies although the consequences of this on head-gaze stability remain unclear. The purpose of this study was to examine if providing individuals with visual feedback of their head-gaze orientation impacts tibial and head accelerations, shock attenuation and head-gaze motion during preferred speed running at different stride frequencies. Fifteen strides from twelve recreational runners running on a treadmill at their preferred speed were collected during five stride frequencies (preferred, ±10% and ±20% of preferred) in two visual task conditions (with and without real-time visual feedback of head-gaze orientation)...
2016: PloS One
Michael P Barry, Gislin Dagnelie
INTRODUCTION: Most visual neuroprostheses use an external camera for image acquisition. This adds two complications to phosphene perception: (1) stimulation locus will not change with eye movements; and (2) external cameras can be aimed in directions different from the user's intended direction of gaze. Little is known about the stability of where users perceive light sources to be or whether they will adapt to changes in camera orientation. METHODS: Three end-stage retinitis pigmentosa patients implanted with the Argus II participated in this study...
2016: Frontiers in Systems Neuroscience
J McDevitt, K O Appiah-Kubi, R Tierney, W G Wright
In this study, we collected and analyzed preliminary data for the internal consistency of a new condensed model to assess vestibular and oculomotor impairments following a concussion. We also examined this model's ability to discriminate concussed athletes from healthy controls. Each participant was tested in a concussion assessment protocol that consisted of the Neurocom's Sensory Organization Test (SOT), Balance Error Scoring System exam, and a series of 8 vestibular and oculomotor assessments. Of these 10 assessments, only the SOT, near point convergence, and the signs and symptoms (S/S) scores collected following optokinetic stimulation, the horizontal eye saccades test, and the gaze stabilization test were significantly correlated with health status, and were used in further analyses...
August 2016: International Journal of Sports Medicine
Ola Alsalman, Jan Ost, Robby Vanspauwen, Catherine Blaivie, Dirk De Ridder, Sven Vanneste
Vestibular signals are of significant importance for variable functions including gaze stabilization, spatial perception, navigation, cognition, and bodily self-consciousness. The vestibular network governs functions that might be impaired in patients affected with vestibular dysfunction. It is currently unclear how different brain regions/networks process vestibular information and integrate the information into a unified spatial percept related to somatosensory awareness and whether people with recurrent balance complaints have a neural signature as a trait affecting their development of chronic symptoms of vertigo...
2016: PloS One
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