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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
#1
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/28434862/consequences-of-the-oculomotor-cycle-for-the-dynamics-of-perception
#2
Marco Boi, Martina Poletti, Jonathan D Victor, Michele Rucci
Much evidence indicates that humans and other species process large-scale visual information before fine spatial detail. Neurophysiological data obtained with paralyzed eyes suggest that this coarse-to-fine sequence results from spatiotemporal filtering by neurons in the early visual pathway. However, the eyes are normally never stationary: rapid gaze shifts (saccades) incessantly alternate with slow fixational movements. To investigate the consequences of this oculomotor cycle on the dynamics of perception, we combined spectral analysis of visual input signals, neural modeling, and gaze-contingent control of retinal stimulation in humans...
April 17, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28429648/-the-influence-of-scene-context-on-parafoveal-processing-of-objects
#3
Monica S Castelhano, Effie J Pereira
Many studies in reading have shown the enhancing effect of context on the processing of a word before it is directly fixated (parafoveal processing of words; Balota et al., 1985; Balota & Rayner, 1983; Ehrlich & Rayner, 1981). Here, we examined whether scene context influences the parafoveal processing of objects and enhances the extraction of object information. Using a modified boundary paradigm (Rayner, 1975), the Dot-Boundary paradigm, participants fixated on a suddenly-onsetting cue before the preview object would onset 4° away...
April 21, 2017: Quarterly Journal of Experimental Psychology: QJEP
https://www.readbyqxmd.com/read/28428540/temporal-dynamics-of-saccades-explained-by-a-self-paced-process
#4
Roy Amit, Dekel Abeles, Izhar Bar-Gad, Shlomit Yuval-Greenberg
Sensory organs are thought to sample the environment rhythmically thereby providing periodic perceptual input. Whisking and sniffing are governed by oscillators which impose rhythms on the motor-control of sensory acquisition and consequently on sensory input. Saccadic eye movements are the main visual sampling mechanism in primates, and were suggested to constitute part of such a rhythmic exploration system. In this study we characterized saccadic rhythmicity, and examined whether it is consistent with autonomous oscillatory generator or with self-paced generation...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28426352/the-risky-reading-strategy-revisited-new-simulations-using-e-z-reader
#5
Victoria A McGowan, Erik D Reichle
Eye-movement studies have demonstrated that, relative to college-aged readers, older readers of alphabetic languages like English and German tend to read more slowly, making more frequent, longer fixations, longer saccades, skipping more words, but also making more frequent regressions. These findings have led to suggestions that older readers either adopt a "risky" strategy of using context to "guess" words as a way of compensating for slower rates of lexical processing (Rayner, Reichle, Stroud, Williams, & Pollatsek, 2006), or that they have a smaller and more asymmetrical perceptual span (Laubrock, Kliegl, & Engbert, 2005)...
April 20, 2017: Quarterly Journal of Experimental Psychology: QJEP
https://www.readbyqxmd.com/read/28424915/optimal-eye-movement-strategies-a-comparison-of-neurosurgeons-gaze-patterns-when-using-a-surgical-microscope
#6
Shahram Eivazi, Ahmad Hafez, Wolfgang Fuhl, Hoorieh Afkari, Enkelejda Kasneci, Martin Lehecka, Roman Bednarik
BACKGROUND: Previous studies have consistently demonstrated gaze behaviour differences related to expertise during various surgical procedures. In micro-neurosurgery, however, there is a lack of evidence of empirically demonstrated individual differences associated with visual attention. It is unknown exactly how neurosurgeons see a stereoscopic magnified view in the context of micro-neurosurgery and what this implies for medical training. METHOD: We report on an investigation of the eye movement patterns in micro-neurosurgery using a state-of-the-art eye tracker...
April 19, 2017: Acta Neurochirurgica
https://www.readbyqxmd.com/read/28422031/the-importance-of-labyrinthine-examination-in-the-prognosis-and-therapy-for-balance-in-spinocerebellar-ataxia
#7
João Henrique Faryniuk, Bianca Simone Zeigelboim, Hélio Afonso Ghizoni Teive, Vinicius Ribas Fo, Paulo Breno Noronha Liberalesso, Jair Mendes Marques
INTRODUCTION: Spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative diseases that are characterized by the presence of progressive cerebellar ataxia. OBJECTIVE: Identify vestibular disorders and demonstrate the importance of labyrinthine examination in the prognosis and therapy for balance in patients with SCAs. MATERIALS AND METHODS: The study had a retrospective cross-sectional design and evaluated 57 patients, mean age of 41...
April 19, 2017: International Tinnitus Journal
https://www.readbyqxmd.com/read/28418326/artifact-in-pediatric-oculomotor-findings-during-videonystagmography-a-retrospective-analysis
#8
Steven M Doettl, Patrick N Plyler, Devin L McCaslin
BACKGROUND: Accurate measurement of oculomotor function using videonystagmography (VNG) is imperative for diagnosis and management of patients with reported dizziness. The oculomotor evaluation during VNG utilizes video-oculography providing valuable information regarding the central structures and pathways that control eye movements. Artifact may have an effect on the overall validity and reliability of VNG oculomotor tracings and can result from patient and/or recording errors. It is postulated that artifact could occur more frequently in the pediatric population due to both patient and equipment factors...
April 2017: Journal of the American Academy of Audiology
https://www.readbyqxmd.com/read/28414501/spelling-ability-selectively-predicts-the-magnitude-of-disruption-in-unspaced-text-reading
#9
Aaron Veldre, Denis Drieghe, Sally Andrews
We examined the effect of individual differences in written language proficiency on unspaced text reading in a large sample of skilled adult readers who were assessed on reading comprehension and spelling ability. Participants' eye movements were recorded as they read sentences containing a low or high frequency target word, presented with standard interword spacing, or in one of three unsegmented text conditions that either preserved or eliminated word boundary information. The average data replicated previous studies: unspaced text reading was associated with increased fixation durations, a higher number of fixations, more regressions, reduced saccade length, and an inflation of the word frequency effect...
April 17, 2017: Journal of Experimental Psychology. Human Perception and Performance
https://www.readbyqxmd.com/read/28413825/color-change-detection-activity-in-the-primate-superior-colliculus
#10
James P Herman, Richard J Krauzlis
The primate superior colliculus (SC) is a midbrain structure that participates in the control of spatial attention. Previous studies examining the role of the SC in attention have mostly used luminance-based visual features (e.g., motion, contrast) as the stimuli and saccadic eye movements as the behavioral response, both of which are known to modulate the activity of SC neurons. To explore the limits of the SC's involvement in the control of spatial attention, we recorded SC neuronal activity during a task using color, a visual feature dimension not traditionally associated with the SC, and required monkeys to detect threshold-level changes in the saturation of a cued stimulus by releasing a joystick during maintained fixation...
March 2017: ENeuro
https://www.readbyqxmd.com/read/28413199/rapid-and-coordinated-processing-of-global-motion-images-by-local-clusters-of-retinal-ganglion-cells
#11
Akihiro Matsumoto, Masao Tachibana
Even when the body is stationary, the whole retinal image is always in motion by fixational eye movements and saccades that move the eye between fixation points. Accumulating evidence indicates that the brain is equipped with specific mechanisms for compensating for the global motion induced by these eye movements. However, it is not yet fully understood how the retina processes global motion images during eye movements. Here we show that global motion images evoke novel coordinated firing in retinal ganglion cells (GCs)...
2017: Proceedings of the Japan Academy. Series B, Physical and Biological Sciences
https://www.readbyqxmd.com/read/28410279/ocular-motor-manifestations-of-multiple-sclerosis
#12
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/28406944/fixational-saccades-are-more-disconjugate-in-adults-than-in-children
#13
Aasef G Shaikh, Fatema F Ghasia
PURPOSE: Fixational eye movements are of particular interest for three reasons. They are critical for preventing visual fading and enhancing visual perception; their disconjugacy allows scanning in three dimensions, and their neural correlates span through the cortico-striatal, striato-collicular and brainstem networks. Fixational eye movements are altered in various pediatric ophthalmologic and neurologic disorders. The goal of this study was to compare the dynamics of fixational eye movements in normal children and adults...
2017: PloS One
https://www.readbyqxmd.com/read/28406688/reading-sentences-of-uniform-word-length-evidence-for-the-adaptation-of-the-preferred-saccade-length-during-reading
#14
Michael G Cutter, Denis Drieghe, Simon P Liversedge
In the current study, the effect of removing word length variability within sentences on spatial aspects of eye movements during reading was investigated. Participants read sentences that were uniform in terms of word length, with each sentence consisting entirely of three-, four-, or five-letter words, or a combination of these word lengths. Several interesting findings emerged. Adaptation of the preferred saccade length occurred for sentences with different uniform word length; participants would be more accurate at making short saccades while reading uniform sentences of three-letter words, while they would be more accurate at making long saccades while reading uniform sentences of five-letter words...
April 13, 2017: Journal of Experimental Psychology. Human Perception and Performance
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/28400326/developmental-visual-perception-deficits-with-no-indications-of-prosopagnosia-in-a-child-with-abnormal-eye-movements
#16
Sharon Gilaie-Dotan, Ravid Doron
Visual categories are associated with eccentricity biases in high-order visual cortex: Faces and reading with foveally-biased regions, while common objects and space with mid- and peripherally-biased regions. As face perception and reading are among the most challenging human visual skills, and are often regarded as the peak achievements of a distributed neural network supporting common objects perception, it is unclear why objects, which also rely on foveal vision to be processed, are associated with mid-peripheral rather than with a foveal bias...
April 9, 2017: Neuropsychologia
https://www.readbyqxmd.com/read/28396415/variations-in-crowding-saccadic-precision-and-spatial-localization-reveal-the-shared-topology-of-spatial-vision
#17
John A Greenwood, Martin Szinte, Bilge Sayim, Patrick Cavanagh
Visual sensitivity varies across the visual field in several characteristic ways. For example, sensitivity declines sharply in peripheral (vs. foveal) vision and is typically worse in the upper (vs. lower) visual field. These variations can affect processes ranging from acuity and crowding (the deleterious effect of clutter on object recognition) to the precision of saccadic eye movements. Here we examine whether these variations can be attributed to a common source within the visual system. We first compared the size of crowding zones with the precision of saccades using an oriented clock target and two adjacent flanker elements...
April 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28392112/a-descending-neuron-correlated-with-the-rapid-steering-maneuvers-of-flying-drosophila
#18
Bettina Schnell, Ivo G Ros, Michael H Dickinson
To navigate through the world, animals must stabilize their path against disturbances and change direction to avoid obstacles and to search for resources [1, 2]. Locomotion is thus guided by sensory cues but also depends on intrinsic processes, such as motivation and physiological state. Flies, for example, turn with the direction of large-field rotatory motion, an optomotor reflex that is thought to help them fly straight [3-5]. Occasionally, however, they execute fast turns, called body saccades, either spontaneously or in response to patterns of visual motion such as expansion [6-8]...
March 30, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28389741/capturing-saccades-in-multiple-sclerosis-with-a-digitized-test-of-rapid-number-naming
#19
Clotilde Hainline, John-Ross Rizzo, Todd E Hudson, Weiwei Dai, Joel Birkemeier, Jenelle Raynowska, Rachel C Nolan, Lisena Hasanaj, Ivan Selesnick, Teresa C Frohman, Elliot M Frohman, Steven L Galetta, Laura J Balcer, Janet C Rucker
The King-Devick (K-D) test of rapid number naming is a visual performance measure that captures saccadic eye movements. Patients with multiple sclerosis (MS) have slowed K-D test times associated with neurologic disability and reduced quality of life. We assessed eye movements during the K-D test to identify characteristics associated with slowed times. Participants performed a computerized K-D test with video-oculography. The 25-Item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) and its 10-Item Neuro-Ophthalmic Supplement measured vision-specific quality of life (VSQOL)...
April 7, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28388698/the-magnification-factor-accounts-for-the-greater-hypometria-and-imprecision-of-larger-saccades-evidence-from-a-parametric-human-behavioral-study
#20
Françoise Vitu, Soazig Casteau, Hossein Adeli, Gregory J Zelinsky, Eric Castet
Saccades quite systematically undershoot a peripheral visual target by about 10% of its eccentricity while becoming more variable, mainly in amplitude, as the target becomes more peripheral. This undershoot phenomenon has been interpreted as the strategic adjustment of saccadic gain downstream of the superior colliculus (SC), where saccades are programmed. Here, we investigated whether the eccentricity-related increase in saccades' hypometria and imprecision might not instead result from overrepresentation of space closer to the fovea in the SC and visual-cortical areas...
April 1, 2017: Journal of Vision
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