Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex

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Gregory D. Scott

2014-03-01

Full Text Available Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants were limited by inter-subject variability of Heschl’s gyrus. In addition to reorganized auditory cortex (cross-modal plasticity, a second gap in our understanding is the contribution of altered modality-specific cortices (visual intramodal plasticity in this case, as well as supramodal and multisensory cortices, especially when target detection is required across contrasts. Here we address these gaps by comparing fMRI signal change for peripheral versus perifoveal visual stimulation (11-15° vs. 2°-7° in congenitally deaf and hearing participants in a blocked experimental design with two analytical approaches: a Heschl’s gyrus region of interest analysis and a whole brain analysis. Our results using individually-defined primary auditory cortex (Heschl’s gyrus indicate that fMRI signal change for more peripheral stimuli was greater than perifoveal in deaf but not in hearing participants. Whole-brain analyses revealed differences between deaf and hearing participants for peripheral versus perifoveal visual processing in extrastriate visual cortex including primary auditory cortex, MT+/V5, superior-temporal auditory and multisensory and/or supramodal regions, such as posterior parietal cortex, frontal eye fields, anterior cingulate, and supplementary eye fields. Overall, these data demonstrate the contribution of neuroplasticity in multiple systems including primary auditory cortex, supramodal and multisensory regions, to altered visual processing in

Foveal Processing Under Concurrent Peripheral Load in Profoundly Deaf Adults

Science.gov (United States)

2016-01-01

Development of the visual system typically proceeds in concert with the development of audition. One result is that the visual system of profoundly deaf individuals differs from that of those with typical auditory systems. While past research has suggested deaf people have enhanced attention in the visual periphery, it is still unclear whether or not this enhancement entails deficits in central vision. Profoundly deaf and typically hearing adults were administered a variant of the useful field of view task that independently assessed performance on concurrent central and peripheral tasks. Identification of a foveated target was impaired by a concurrent selective peripheral attention task, more so in profoundly deaf adults than in the typically hearing. Previous findings of enhanced performance on the peripheral task were not replicated. These data are discussed in terms of flexible allocation of spatial attention targeted towards perceived task demands, and support a modified “division of labor” hypothesis whereby attentional resources co-opted to process peripheral space result in reduced resources in the central visual field. PMID:26657078

Postural Control and Gait Performance in the Diabetic Peripheral Neuropathy: A Systematic Review.

Science.gov (United States)

Mustapa, Amirah; Justine, Maria; Mohd Mustafah, Nadia; Jamil, Nursuriati; Manaf, Haidzir

2016-01-01

Purpose. The aim of this paper is to review the published studies on the characteristics of impairments in the postural control and gait performance in diabetic peripheral neuropathy (DPN). Methods. A review was performed by obtaining publication of all papers reporting on the postural control and gait performance in DPN from Google Scholar, Ovid, SAGE, Springerlink, Science Direct (SD), EBSCO Discovery Service, and Web of Science databases. The keywords used for searching were "postural control," "balance," "gait performance," "diabetes mellitus," and "diabetic peripheral neuropathy." Results. Total of 4,337 studies were hit in the search. 1,524 studies were screened on their titles and citations. Then, 79 studies were screened on their abstract. Only 38 studies were eligible to be selected: 17 studies on postural control and 21 studies on the gait performance. Most previous researches were found to have strong evidence of postural control impairments and noticeable gait deficits in DPN. Deterioration of somatosensory, visual, and vestibular systems with the pathologic condition of diabetes on cognitive impairment causes further instability of postural and gait performance in DPN. Conclusions. Postural instability and gait imbalance in DPN may contribute to high risk of fall incidence, especially in the geriatric population. Thus, further works are crucial to highlight this fact in the hospital based and community adults.

Which visual sight skill tested and developed the interaction between central and peripheral vision case duels dribbling soccer skills

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Zerf Mohammed

2016-09-01

Full Text Available The present paper analyses the effects of visual keep sight to test and develop the interaction between central and peripheral vision the case of duels dribbling among soccer under 17 years. Where This research aims to propose a method evaluating and coaching this skill in the absence of laboratory tests and virtual visual exercises as a way for Algerian coaches to control the progress of their players. From the principle that the team which wins the most duels has the best chance of winning the game. [1] Our research supports the hypothesis which confirms in one hand that Dynamic visual acuity is the combine between Peripheral and Central vision to have one eye on the ball and the other on the defined [2] . While some authors confirm that the Top-class football players do not watch their steps, but dribble with their heads up [3]. Whereas Previous studies confirm estimate of distance ball foot player is the strategy to master this skill [4] which requires the involvement of the commitment of peripheral vision for information and central vision to master the ball [5]. From the proof and results statistics applied in the current study, we confirm that narrow spaces require the interaction of central vision than peripheral vision. Otherwise, free spaces require peripheral vision than the central vision. Which leaves us to confirm that peripheral vision in the limited space [6] can suffer because the player needs to pay close attention to each contact with the ball [7].

Postural Control and Gait Performance in the Diabetic Peripheral Neuropathy: A Systematic Review

Directory of Open Access Journals (Sweden)

Amirah Mustapa

2016-01-01

Full Text Available Purpose. The aim of this paper is to review the published studies on the characteristics of impairments in the postural control and gait performance in diabetic peripheral neuropathy (DPN. Methods. A review was performed by obtaining publication of all papers reporting on the postural control and gait performance in DPN from Google Scholar, Ovid, SAGE, Springerlink, Science Direct (SD, EBSCO Discovery Service, and Web of Science databases. The keywords used for searching were “postural control,” “balance,” “gait performance,” “diabetes mellitus,” and “diabetic peripheral neuropathy.” Results. Total of 4,337 studies were hit in the search. 1,524 studies were screened on their titles and citations. Then, 79 studies were screened on their abstract. Only 38 studies were eligible to be selected: 17 studies on postural control and 21 studies on the gait performance. Most previous researches were found to have strong evidence of postural control impairments and noticeable gait deficits in DPN. Deterioration of somatosensory, visual, and vestibular systems with the pathologic condition of diabetes on cognitive impairment causes further instability of postural and gait performance in DPN. Conclusions. Postural instability and gait imbalance in DPN may contribute to high risk of fall incidence, especially in the geriatric population. Thus, further works are crucial to highlight this fact in the hospital based and community adults.

Enhanced peripheral visual processing in congenitally deaf humans is supported by multiple brain regions, including primary auditory cortex

OpenAIRE

Scott, Gregory D.; Karns, Christina M.; Dow, Mark W.; Stevens, Courtney; Neville, Helen J.

2014-01-01

Brain reorganization associated with altered sensory experience clarifies the critical role of neuroplasticity in development. An example is enhanced peripheral visual processing associated with congenital deafness, but the neural systems supporting this have not been fully characterized. A gap in our understanding of deafness-enhanced peripheral vision is the contribution of primary auditory cortex. Previous studies of auditory cortex that use anatomical normalization across participants wer...

Case of Unilateral Peripheral Cone Dysfunction

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Yujin Mochizuki

2012-05-01

Full Text Available Purpose: Peripheral cone dystrophy is a subgroup of cone dystrophy, and only 4 cases have been reported. We present a patient with unilateral peripheral cone dysfunction and report the functional changes determined by electrophysiological tests and ultrastructural changes determined by spectral domain optical coherence tomography (SD-OCT. Case: A 34-year-old woman complained of blurred vision in both eyes. Our examination showed that her visual acuity was 0.05 OD and 0.2 OS. A relative afferent pupillary defect was present in her right eye. The results of slit-lamp examination, ophthalmoscopy, and fluorescein angiography were normal except for pallor of the right optic disc. SD-OCT showed a diffuse thinning of the retina in the posterior pole of the right eye. A severe constriction of the visual fields was found in both eyes but more in the right eye. The photopic full-field electroretinograms (ERGs were reduced in the right eye but normal in the left eye. The multifocal ERGs were severely reduced throughout the visual field except in the central area of the right eye. The multifocal ERGs from the left eye were normal. The pattern visual evoked responses were within the normal range in both eyes. She had a 5-year history of sniffing paint thinner. Results: Although the visual dysfunction was initially suspected to be due to psychological problems from the results of subjective tests, objective tests indicated a peripheral cone dysfunction in the right eye. The pathophysiological mechanism and the relationship with thinner sniffing were not determined. Conclusions: Our findings indicate that peripheral cone dysfunction can occur unilaterally. Electrophysiology and SD-OCT are valuable tests to perform to determine the pathogenesis of unusual ocular findings objectively.

Are Visual Peripheries Forever Young?

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Kalina Burnat

2015-01-01

Full Text Available The paper presents a concept of lifelong plasticity of peripheral vision. Central vision processing is accepted as critical and irreplaceable for normal perception in humans. While peripheral processing chiefly carries information about motion stimuli features and redirects foveal attention to new objects, it can also take over functions typical for central vision. Here I review the data showing the plasticity of peripheral vision found in functional, developmental, and comparative studies. Even though it is well established that afferent projections from central and peripheral retinal regions are not established simultaneously during early postnatal life, central vision is commonly used as a general model of development of the visual system. Based on clinical studies and visually deprived animal models, I describe how central and peripheral visual field representations separately rely on early visual experience. Peripheral visual processing (motion is more affected by binocular visual deprivation than central visual processing (spatial resolution. In addition, our own experimental findings show the possible recruitment of coarse peripheral vision for fine spatial analysis. Accordingly, I hypothesize that the balance between central and peripheral visual processing, established in the course of development, is susceptible to plastic adaptations during the entire life span, with peripheral vision capable of taking over central processing.

Are visual peripheries forever young?

Science.gov (United States)

Burnat, Kalina

2015-01-01

The paper presents a concept of lifelong plasticity of peripheral vision. Central vision processing is accepted as critical and irreplaceable for normal perception in humans. While peripheral processing chiefly carries information about motion stimuli features and redirects foveal attention to new objects, it can also take over functions typical for central vision. Here I review the data showing the plasticity of peripheral vision found in functional, developmental, and comparative studies. Even though it is well established that afferent projections from central and peripheral retinal regions are not established simultaneously during early postnatal life, central vision is commonly used as a general model of development of the visual system. Based on clinical studies and visually deprived animal models, I describe how central and peripheral visual field representations separately rely on early visual experience. Peripheral visual processing (motion) is more affected by binocular visual deprivation than central visual processing (spatial resolution). In addition, our own experimental findings show the possible recruitment of coarse peripheral vision for fine spatial analysis. Accordingly, I hypothesize that the balance between central and peripheral visual processing, established in the course of development, is susceptible to plastic adaptations during the entire life span, with peripheral vision capable of taking over central processing.

Visual function, driving safety, and the elderly.

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Keltner, J L; Johnson, C A

1987-09-01

The authors have conducted a survey of the Departments of Motor Vehicles in all 50 states, the District of Columbia, and Puerto Rico requesting information about the visual standards, accidents, and conviction rates for different age groups. In addition, we have reviewed the literature on visual function and traffic safety. Elderly drivers have a greater number of vision problems that affect visual acuity and/or peripheral visual fields. Although the elderly are responsible for a small percentage of the total number of traffic accidents, the types of accidents they are involved in (e.g., failure to yield the right-of-way, intersection collisions, left turns onto crossing streets) may be related to peripheral and central visual field problems. Because age-related changes in performance occur at different rates for various individuals, licensing of the elderly driver should be based on functional abilities rather than age. Based on information currently available, we can make the following recommendations: (1) periodic evaluations of visual acuity and visual fields should be performed every 1 to 2 years in the population over age 65; (2) drivers of any age with multiple accidents or moving violations should have visual acuity and visual fields evaluated; and (3) a system should be developed for physicians to report patients with potentially unsafe visual function. The authors believe that these recommendations may help to reduce the number of traffic accidents that result from peripheral visual field deficits.

Functional visual fields: relationship of visual field areas to self-reported function.

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Subhi, Hikmat; Latham, Keziah; Myint, Joy; Crossland, Michael D

2017-07-01

The aim of this study is to relate areas of the visual field to functional difficulties to inform the development of a binocular visual field assessment that can reflect the functional consequences of visual field loss. Fifty-two participants with peripheral visual field loss undertook binocular assessment of visual fields using the 30-2 and 60-4 SITA Fast programs on the Humphrey Field Analyser, and mean thresholds were derived. Binocular visual acuity, contrast sensitivity and near reading performance were also determined. Self-reported overall and mobility function were assessed using the Dutch ICF Activity Inventory. Greater visual field loss (0-60°) was associated with worse self-reported function both overall (R 2 = 0.50; p function (R 2 = 0.61, p function in multiple regression analyses. Superior and inferior visual field areas related similarly to mobility function (R 2 = 0.56, p function in multiple regression analysis. Mean threshold of the binocular visual field to 60° eccentricity is a good predictor of self-reported function overall, and particularly of mobility function. Both the central (0-30°) and peripheral (30-60°) mean threshold are good predictors of self-reported function, but the peripheral (30-0°) field is a slightly better predictor of mobility function, and should not be ignored when considering functional consequences of field loss. The inferior visual field is a slightly stronger predictor of perceived overall and mobility function than the superior field. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

Ultrasound Guidance as a Rescue Technique for Peripheral Intravenous Cannulation

National Research Council Canada - National Science Library

Pappas, Nancy L; Michaud, Terese E; Wolbers, Russell M; Steward, James C; Fevurly, Thomas A; Samolitis, Timothy J; Shoneboom, Bruce A; Watts, Dorraine D

2006-01-01

Peripheral intravenous (W) cannulation can be difficult to perform using the traditional landmark or visual/palpation technique in patients with access difficulties such as deep, sclerotic, small, or fragile veins...

Rodent model for assessing the long term safety and performance of peripheral nerve recording electrodes

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Vasudevan, Srikanth; Patel, Kunal; Welle, Cristin

2017-02-01

Objective. In the US alone, there are approximately 185 000 cases of limb amputation annually, which can reduce the quality of life for those individuals. Current prosthesis technology could be improved by access to signals from the nervous system for intuitive prosthesis control. After amputation, residual peripheral nerves continue to convey motor signals and electrical stimulation of these nerves can elicit sensory percepts. However, current technology for extracting information directly from peripheral nerves has limited chronic reliability, and novel approaches must be vetted to ensure safe long-term use. The present study aims to optimize methods to establish a test platform using rodent model to assess the long term safety and performance of electrode interfaces implanted in the peripheral nerves. Approach. Floating Microelectrode Arrays (FMA, Microprobes for Life Sciences) were implanted into the rodent sciatic nerve. Weekly in vivo recordings and impedance measurements were performed in animals to assess performance and physical integrity of electrodes. Motor (walking track analysis) and sensory (Von Frey) function tests were used to assess change in nerve function due to the implant. Following the terminal recording session, the nerve was explanted and the health of axons, myelin and surrounding tissues were assessed using immunohistochemistry (IHC). The explanted electrodes were visualized under high magnification using scanning electrode microscopy (SEM) to observe any physical damage. Main results. Recordings of axonal action potentials demonstrated notable session-to-session variability. Impedance of the electrodes increased upon implantation and displayed relative stability until electrode failure. Initial deficits in motor function recovered by 2 weeks, while sensory deficits persisted through 6 weeks of assessment. The primary cause of failure was identified as lead wire breakage in all of animals. IHC indicated myelinated and unmyelinated axons

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis.

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Schiefer, Matthew; Tan, Daniel; Sidek, Steven M; Tyler, Dustin J

2016-02-01

Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject's sense of embodiment with a survey and his self-confidence. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

Mini-review: Far peripheral vision.

Science.gov (United States)

Simpson, Michael J

2017-11-01

The region of far peripheral vision, beyond 60 degrees of visual angle, is important to the evaluation of peripheral dark shadows (negative dysphotopsia) seen by some intraocular lens (IOL) patients. Theoretical calculations show that the limited diameter of an IOL affects ray paths at large angles, leading to a dimming of the main image for small pupils, and to peripheral illumination by light bypassing the IOL for larger pupils. These effects are rarely bothersome, and cataract surgery is highly successful, but there is a need to improve the characterization of far peripheral vision, for both pseudophakic and phakic eyes. Perimetry is the main quantitative test, but the purpose is to evaluate pathologies rather than characterize vision (and object and image regions are no longer uniquely related in the pseudophakic eye). The maximum visual angle is approximately 105 0 , but there is limited information about variations with age, race, or refractive error (in case there is an unexpected link with the development of myopia), or about how clear cornea, iris location, and the limiting retina are related. Also, the detection of peripheral motion is widely recognized to be important, yet rarely evaluated. Overall, people rarely complain specifically about this visual region, but with "normal" vision including an IOL for >5% of people, and increasing interest in virtual reality and augmented reality, there are new reasons to characterize peripheral vision more completely. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intraarterial digital subtraction angiography of peripheral arteries with isotonic contrast material

International Nuclear Information System (INIS)

Yashiro, Naobumi; Itai, Yuji; Ohtomo, Kuni; Furui, Shigeru; Iio, Masahiro

1984-01-01

Intraarterial digital subtraction angiography (IADSA) of peripheral arteries with isotonic contrast material, which was prepared by diluting meglumine amidotrizoate (65% Angiografin), was performed in ten patients. In six, both IADSA and conventional screen-film arteriography were performed for comparison. Painless peripheral arteriography was achieved by IADSA with isotonic contrast material. Five IADSAs were safely done on an outpatient basis. Visualization of arteries by IADSA was satisfactory, but the details of smaller arteries were better shown by screen-film arteriography. Visualization of faint stains was better in IADSA. The authors believe that IADSA with isotonic contrast material is a method of choice for the diagnosis of vascular diseases and tumorous conditions of extremities, as well as for the purpose of preoperative vascular mapping. It is safely performed with smaller dose of contrast material on outpatient basis, and with less discomfort and cost for the patient. (author)

Sensory feedback by peripheral nerve stimulation improves task performance in individuals with upper limb loss using a myoelectric prosthesis

Science.gov (United States)

Schiefer, Matthew; Tan, Daniel; Sidek, Steven M.; Tyler, Dustin J.

2016-02-01

Objective. Tactile feedback is critical to grip and object manipulation. Its absence results in reliance on visual and auditory cues. Our objective was to assess the effect of sensory feedback on task performance in individuals with limb loss. Approach. Stimulation of the peripheral nerves using implanted cuff electrodes provided two subjects with sensory feedback with intensity proportional to forces on the thumb, index, and middle fingers of their prosthetic hand during object manipulation. Both subjects perceived the sensation on their phantom hand at locations corresponding to the locations of the forces on the prosthetic hand. A bend sensor measured prosthetic hand span. Hand span modulated the intensity of sensory feedback perceived on the thenar eminence for subject 1 and the middle finger for subject 2. We performed three functional tests with the blindfolded subjects. First, the subject tried to determine whether or not a wooden block had been placed in his prosthetic hand. Second, the subject had to locate and remove magnetic blocks from a metal table. Third, the subject performed the Southampton Hand Assessment Procedure (SHAP). We also measured the subject’s sense of embodiment with a survey and his self-confidence. Main results. Blindfolded performance with sensory feedback was similar to sighted performance in the wooden block and magnetic block tasks. Performance on the SHAP, a measure of hand mechanical function and control, was similar with and without sensory feedback. An embodiment survey showed an improved sense of integration of the prosthesis in self body image with sensory feedback. Significance. Sensory feedback by peripheral nerve stimulation improved object discrimination and manipulation, embodiment, and confidence. With both forms of feedback, the blindfolded subjects tended toward results obtained with visual feedback.

Neurophysiological assessment of auditory, peripheral nerve, somatosensory, and visual system function after developmental exposure to gasoline, E15, and E85 vapors.

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U.S. Environmental Protection Agency — Visual, auditory, somatosensory, and peripheral nerve evoked responses. This dataset is associated with the following publication: Herr , D., D. Freeborn , L. Degn ,...

Deployment of spatial attention to words in central and peripheral vision.

Science.gov (United States)

Ducrot, Stéphanie; Grainger, Jonathan

2007-05-01

Four perceptual identification experiments examined the influence of spatial cues on the recognition of words presented in central vision (with fixation on either the first or last letter of the target word) and in peripheral vision (displaced left or right of a central fixation point). Stimulus location had a strong effect on word identification accuracy in both central and peripheral vision, showing a strong right visual field superiority that did not depend on eccentricity. Valid spatial cues improved word identification for peripherally presented targets but were largely ineffective for centrally presented targets. Effects of spatial cuing interacted with visual field effects in Experiment 1, with valid cues reducing the right visual field superiority for peripherally located targets, but this interaction was shown to depend on the type of neutral cue. These results provide further support for the role of attentional factors in visual field asymmetries obtained with targets in peripheral vision but not with centrally presented targets.

Competitive interactions of attentional resources in early visual cortex during sustained visuospatial attention within or between visual hemifields: evidence for the different-hemifield advantage.

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Walter, Sabrina; Quigley, Cliodhna; Mueller, Matthias M

2014-05-01

Performing a task across the left and right visual hemifields results in better performance than in a within-hemifield version of the task, termed the different-hemifield advantage. Although recent studies used transient stimuli that were presented with long ISIs, here we used a continuous objective electrophysiological (EEG) measure of competitive interactions for attentional processing resources in early visual cortex, the steady-state visual evoked potential (SSVEP). We frequency-tagged locations in each visual quadrant and at central fixation by flickering light-emitting diodes (LEDs) at different frequencies to elicit distinguishable SSVEPs. Stimuli were presented for several seconds, and participants were cued to attend to two LEDs either in one (Within) or distributed across left and right visual hemifields (Across). In addition, we introduced two reference measures: one for suppressive interactions between the peripheral LEDs by using a task at fixation where attention was withdrawn from the periphery and another estimating the upper bound of SSVEP amplitude by cueing participants to attend to only one of the peripheral LEDs. We found significantly greater SSVEP amplitude modulations in Across compared with Within hemifield conditions. No differences were found between SSVEP amplitudes elicited by the peripheral LEDs when participants attended to the centrally located LEDs compared with when peripheral LEDs had to be ignored in Across and Within trials. Attending to only one LED elicited the same SSVEP amplitude as Across conditions. Although behavioral data displayed a more complex pattern, SSVEP amplitudes were well in line with the predictions of the different-hemifield advantage account during sustained visuospatial attention.

Immune mapping of the peripheral part of the visual analyzer and optic nerve

Directory of Open Access Journals (Sweden)

V. G. Likhvantseva

2014-10-01

Full Text Available Aim. To perform immune mapping of the peripheral part of visual analyzer and optic nerve in order to identify potential antigenic targets of autoimmune attack. Methods. Eyes enucleated for terminal painful glaucoma (n = 30 were studied. Immunohistochemistry (IHC was performed on paraffin-embedded sections of isolated retina and optic nerve using a broad panel of antibodies, i.e., monoclonal murine anti-MBP (myelin basic protein antibodies, polyclonal rabbit anti-alpha fodrin antibodies, monoclonal murine anti-NSE2 (neuron-specific enolase antibodies, monoclonal murine anti-GFAP (glial fibrillary acidic protein, and polyclonal rabbit anti-S100 antibodies. IHC reaction was visualized using Mouse and Rabbit Specific HRP / AEC Detection IHC Kit. IHC reaction without primary antibodies included was a negative control. IHC reaction was considered as follows: negative — no specific cellular staining or less than 10 % of cells are stained; mild — 10‑30 % of cells are stained (+; moderate — 30‑75 % of cells are stained (++; marked — more than 75 % of cells are stained (+++; overexpression — 100 % of cells intensively express markers. Additionally, staining intensity was considered as mild (+1, moderate (+2, strong (+3 and intense (+4.Results. Immune mapping with a broad panel of monoclonal antibodies identified ocular structures which were stained with IHC markers. Retina was stained with almost all markers of neural differentiation (i.e., antibodies against NSE, GFAP, S100, and α-fodrin excepting anti-MBP autoantibodies. IHC reaction intensity in retinal layers and structures varied and depended on markers. Moderate (2+ staining with antibodies against MBP, NSE, GFAP, and S100 and marked (3+ staining with antibodies against alpha-fodrin was detected in the cytoplasm of optic nerve glia.Conclusion. Complete labelling of retina structures was performed. As a result, IHC profiles of retinal neurons, optic nerve axons

Immune mapping of the peripheral part of the visual analyzer and optic nerve

Directory of Open Access Journals (Sweden)

V. G. Likhvantseva

2014-01-01

Full Text Available Aim. To perform immune mapping of the peripheral part of visual analyzer and optic nerve in order to identify potential antigenic targets of autoimmune attack. Methods. Eyes enucleated for terminal painful glaucoma (n = 30 were studied. Immunohistochemistry (IHC was performed on paraffin-embedded sections of isolated retina and optic nerve using a broad panel of antibodies, i.e., monoclonal murine anti-MBP (myelin basic protein antibodies, polyclonal rabbit anti-alpha fodrin antibodies, monoclonal murine anti-NSE2 (neuron-specific enolase antibodies, monoclonal murine anti-GFAP (glial fibrillary acidic protein, and polyclonal rabbit anti-S100 antibodies. IHC reaction was visualized using Mouse and Rabbit Specific HRP / AEC Detection IHC Kit. IHC reaction without primary antibodies included was a negative control. IHC reaction was considered as follows: negative — no specific cellular staining or less than 10 % of cells are stained; mild — 10‑30 % of cells are stained (+; moderate — 30‑75 % of cells are stained (++; marked — more than 75 % of cells are stained (+++; overexpression — 100 % of cells intensively express markers. Additionally, staining intensity was considered as mild (+1, moderate (+2, strong (+3 and intense (+4.Results. Immune mapping with a broad panel of monoclonal antibodies identified ocular structures which were stained with IHC markers. Retina was stained with almost all markers of neural differentiation (i.e., antibodies against NSE, GFAP, S100, and α-fodrin excepting anti-MBP autoantibodies. IHC reaction intensity in retinal layers and structures varied and depended on markers. Moderate (2+ staining with antibodies against MBP, NSE, GFAP, and S100 and marked (3+ staining with antibodies against alpha-fodrin was detected in the cytoplasm of optic nerve glia.Conclusion. Complete labelling of retina structures was performed. As a result, IHC profiles of retinal neurons, optic nerve axons

Assistive peripheral phosphene arrays deliver advantages in obstacle avoidance in simulated end-stage retinitis pigmentosa: a virtual-reality study

Science.gov (United States)

Zapf, Marc Patrick H.; Boon, Mei-Ying; Lovell, Nigel H.; Suaning, Gregg J.

2016-04-01

Objective. The prospective efficacy of peripheral retinal prostheses for guiding orientation and mobility in the absence of residual vision, as compared to an implant for the central visual field (VF), was evaluated using simulated prosthetic vision (SPV). Approach. Sighted volunteers wearing a head-mounted display performed an obstacle circumvention task under SPV. Mobility and orientation performance with three layouts of prosthetic vision were compared: peripheral prosthetic vision of higher visual acuity (VA) but limited VF, of wider VF but limited VA, as well as centrally restricted prosthetic vision. Learning curves using these layouts were compared fitting an exponential model to the mobility and orientation measures. Main results. Using peripheral layouts, performance was superior to the central layout. Walking speed with both higher-acuity and wider-angle layouts was 5.6% higher, and mobility errors reduced by 46.4% and 48.6%, respectively, as compared to the central layout. The wider-angle layout yielded the least number of collisions, 63% less than the higher-acuity and 73% less than the central layout. Using peripheral layouts, the number of visual-scanning related head movements was 54.3% (higher-acuity) and 60.7% (wider-angle) lower, as compared to the central layout, and the ratio of time standing versus time walking was 51.9% and 61.5% lower, respectively. Learning curves did not differ between layouts, except for time standing versus time walking, where both peripheral layouts achieved significantly lower asymptotic values compared to the central layout. Significance. Beyond complementing residual vision for an improved performance, peripheral prosthetic vision can effectively guide mobility in the later stages of retinitis pigmentosa (RP) without residual vision. Further, the temporal dynamics of learning peripheral and central prosthetic vision are similar. Therefore, development of a peripheral retinal prosthesis and early implantation to

Relating Standardized Visual Perception Measures to Simulator Visual System Performance

Science.gov (United States)

Kaiser, Mary K.; Sweet, Barbara T.

2013-01-01

Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

Lateralized discrimination of emotional scenes in peripheral vision.

Science.gov (United States)

Calvo, Manuel G; Rodríguez-Chinea, Sandra; Fernández-Martín, Andrés

2015-03-01

This study investigates whether there is lateralized processing of emotional scenes in the visual periphery, in the absence of eye fixations; and whether this varies with emotional valence (pleasant vs. unpleasant), specific emotional scene content (babies, erotica, human attack, mutilation, etc.), and sex of the viewer. Pairs of emotional (positive or negative) and neutral photographs were presented for 150 ms peripherally (≥6.5° away from fixation). Observers judged on which side the emotional picture was located. Low-level image properties, scene visual saliency, and eye movements were controlled. Results showed that (a) correct identification of the emotional scene exceeded the chance level; (b) performance was more accurate and faster when the emotional scene appeared in the left than in the right visual field; (c) lateralization was equivalent for females and males for pleasant scenes, but was greater for females and unpleasant scenes; and (d) lateralization occurred similarly for different emotional scene categories. These findings reveal discrimination between emotional and neutral scenes, and right brain hemisphere dominance for emotional processing, which is modulated by sex of the viewer and scene valence, and suggest that coarse affective significance can be extracted in peripheral vision.

The influence of artificial scotomas on eye movements during visual search

NARCIS (Netherlands)

Cornelissen, FW; Bruin, KJ; Kooijman, AC

Purpose. Fixation durations are normally adapted to the difficulty of the foveal analysis task. We examine to what extent artificial central and peripheral visual field defects interfere with this adaptation process. Methods. Subjects performed a visual search task while their eye movements were

4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents--a phantom study.

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Bunck, Alexander C; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R; Heindel, Walter; Maintz, David

2012-09-01

4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n=14) than by 2D phase contrast flow imaging (n=10). 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Nonuniform Changes in the Distribution of Visual Attention from Visual Complexity and Action: A Driving Simulation Study.

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Park, George D; Reed, Catherine L

2015-02-01

Researchers acknowledge the interplay between action and attention, but typically consider action as a response to successful attentional selection or the correlation of performance on separate action and attention tasks. We investigated how concurrent action with spatial monitoring affects the distribution of attention across the visual field. We embedded a functional field of view (FFOV) paradigm with concurrent central object recognition and peripheral target localization tasks in a simulated driving environment. Peripheral targets varied across 20-60 deg eccentricity at 11 radial spokes. Three conditions assessed the effects of visual complexity and concurrent action on the size and shape of the FFOV: (1) with no background, (2) with driving background, and (3) with driving background and vehicle steering. The addition of visual complexity slowed task performance and reduced the FFOV size but did not change the baseline shape. In contrast, the addition of steering produced not only shrinkage of the FFOV, but also changes in the FFOV shape. Nonuniform performance decrements occurred in proximal regions used for the central task and for steering, independent of interference from context elements. Multifocal attention models should consider the role of action and account for nonhomogeneities in the distribution of attention. © 2015 SAGE Publications.

4D phase contrast flow imaging for in-stent flow visualization and assessment of stent patency in peripheral vascular stents – A phantom study

International Nuclear Information System (INIS)

Bunck, Alexander C.; Jüttner, Alena; Kröger, Jan Robert; Burg, Matthias C.; Kugel, Harald; Niederstadt, Thomas; Tiemann, Klaus; Schnackenburg, Bernhard; Crelier, Gerard R.

2012-01-01

Purpose: 4D phase contrast flow imaging is increasingly used to study the hemodynamics in various vascular territories and pathologies. The aim of this study was to assess the feasibility and validity of MRI based 4D phase contrast flow imaging for the evaluation of in-stent blood flow in 17 commonly used peripheral stents. Materials and methods: 17 different peripheral stents were implanted into a MR compatible flow phantom. In-stent visibility, maximal velocity and flow visualization were assessed and estimates of in-stent patency obtained from 4D phase contrast flow data sets were compared to a conventional 3D contrast-enhanced magnetic resonance angiography (CE-MRA) as well as 2D PC flow measurements. Results: In all but 3 of the tested stents time-resolved 3D particle traces could be visualized inside the stent lumen. Quality of 4D flow visualization and CE-MRA images depended on stent type and stent orientation relative to the magnetic field. Compared to the visible lumen area determined by 3D CE-MRA, estimates of lumen patency derived from 4D flow measurements were significantly higher and less dependent on stent type. A higher number of stents could be assessed for in-stent patency by 4D phase contrast flow imaging (n = 14) than by 2D phase contrast flow imaging (n = 10). Conclusions: 4D phase contrast flow imaging in peripheral vascular stents is feasible and appears advantageous over conventional 3D contrast-enhanced MR angiography and 2D phase contrast flow imaging. It allows for in-stent flow visualization and flow quantification with varying quality depending on stent type

A Pilot Evaluation of On-Road Detection Performance by Drivers with Hemianopia Using Oblique Peripheral Prisms

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Alex R. Bowers

2012-01-01

Full Text Available Aims. Homonymous hemianopia (HH, a severe visual consequence of stroke, causes difficulties in detecting obstacles on the nonseeing (blind side. We conducted a pilot study to evaluate the effects of oblique peripheral prisms, a novel development in optical treatments for HH, on detection of unexpected hazards when driving. Methods. Twelve people with complete HH (median 49 years, range 29–68 completed road tests with sham oblique prism glasses (SP and real oblique prism glasses (RP. A masked evaluator rated driving performance along the 25 km routes on busy streets in Ghent, Belgium. Results. The proportion of satisfactory responses to unexpected hazards on the blind side was higher in the RP than the SP drive (80% versus 30%; P=0.001, but similar for unexpected hazards on the seeing side. Conclusions. These pilot data suggest that oblique peripheral prisms may improve responses of people with HH to blindside hazards when driving and provide the basis for a future, larger-sample clinical trial. Testing responses to unexpected hazards in areas of heavy vehicle and pedestrian traffic appears promising as a real-world outcome measure for future evaluations of HH rehabilitation interventions aimed at improving detection when driving.

Enhanced visual performance in obsessive compulsive personality disorder.

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Ansari, Zohreh; Fadardi, Javad Salehi

2016-12-01

Visual performance is considered as commanding modality in human perception. We tested whether Obsessive-compulsive personality disorder (OCPD) people do differently in visual performance tasks than people without OCPD. One hundred ten students of Ferdowsi University of Mashhad and non-student participants were tested by Structured Clinical Interview for DSM-IV Axis II Personality Disorders (SCID-II), among whom 18 (mean age = 29.55; SD = 5.26; 84% female) met the criteria for OCPD classification; controls were 20 persons (mean age = 27.85; SD = 5.26; female = 84%), who did not met the OCPD criteria. Both groups were tested on a modified Flicker task for two dimensions of visual performance (i.e., visual acuity: detecting the location of change, complexity, and size; and visual contrast sensitivity). The OCPD group had responded more accurately on pairs related to size, complexity, and contrast, but spent more time to detect a change on pairs related to complexity and contrast. The OCPD individuals seem to have more accurate visual performance than non-OCPD controls. The findings support the relationship between personality characteristics and visual performance within the framework of top-down processing model. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Peripheral Visual Cues: Their Fate in Processing and Effects on Attention and Temporal-Order Perception.

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Tünnermann, Jan; Scharlau, Ingrid

2016-01-01

Peripheral visual cues lead to large shifts in psychometric distributions of temporal-order judgments. In one view, such shifts are attributed to attention speeding up processing of the cued stimulus, so-called prior entry. However, sometimes these shifts are so large that it is unlikely that they are caused by attention alone. Here we tested the prevalent alternative explanation that the cue is sometimes confused with the target on a perceptual level, bolstering the shift of the psychometric function. We applied a novel model of cued temporal-order judgments, derived from Bundesen's Theory of Visual Attention. We found that cue-target confusions indeed contribute to shifting psychometric functions. However, cue-induced changes in the processing rates of the target stimuli play an important role, too. At smaller cueing intervals, the cue increased the processing speed of the target. At larger intervals, inhibition of return was predominant. Earlier studies of cued TOJs were insensitive to these effects because in psychometric distributions they are concealed by the conjoint effects of cue-target confusions and processing rate changes.

Trichloropropane and dichlorohydrin associated with painful peripheral neurotoxicity.

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Shi, Xiaobing; Yu, Shengyuan

2013-10-01

Trichloropropane (TCP) and dichlorohydrin are widely used in industrial production; however, TCP and dichlorohydrin poisoning are rarely encountered in clinical practice. There have been no cases of peripheral neurotoxicity previously reported. A cluster of 23 patients who had been exposed to high levels of TCP and dichlorohydrin presented with painful peripheral neuropathy, and the pain was assessed using a visual analogue scale (VAS). Nerve conduction studies (NCS) were performed in all patients. All patients demonstrated symmetrical pin-prick pain in a stocking distribution in the lower limbs, with VAS scores between 3 and 10, with an average score of 6.8. NCS showed a mild mixture of axonal and demyelinating sensorimotor polyneuropathy in 14 of the 23 patients. After administration of standard neuropathic pain medication, pain was relieved in most patients. Painful peripheral neuropathy was the primary symptom observed in our patients, which differs from clinical and animal model reports of TCP or dichlorohydrin poisoning. However, the pathogenesis remains unidentified. TCP may be added to the list of industrial products that are toxic to the peripheral sensory nerves. Copyright © 2013 Elsevier Ltd. All rights reserved.

Peripheral global neglect in high versus low autistic tendency

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Daniel Paul Crewther

2014-04-01

Full Text Available In addition to its core social deficits, autism is characterised by altered visual perception, with a preference for local percept in those high in autistic tendency. Here, the balance of global versus local percepts for the perceptually rivalrous diamond illusion was assessed between groups scoring high and low on the Autism Spectrum Quotient (AQ. The global percept of a diamond shape oscillating horizontally behind three occluders can as easily be interpreted as the local percept of four line elements, each moving vertically. Increasing the luminance contrast of the occluders with respect to background resulted in an increase of initial global percept in both groups, with no difference in sensitivity between groups. Presenting the target further into the periphery resulted in a marked increase in the percentage of global perception with visual field eccentricity. However, while the performance for centrally presented diamond targets was not different between AQ groups, the peripheral global performance of the High AQ group was significantly reduced compared with the Low AQ group. On the basis of other imaging studies, this peripheral but not foveal global perceptual neglect may indicate an abnormal interaction between striate cortex and the Lateral Occipital Complex, or to differences in the deployment of attention between the two groups.

High-resolution ultrasound imaging and noninvasive optoacoustic monitoring of blood variables in peripheral blood vessels

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Petrov, Irene Y.; Petrov, Yuriy; Prough, Donald S.; Esenaliev, Rinat O.

2011-03-01

Ultrasound imaging is being widely used in clinics to obtain diagnostic information non-invasively and in real time. A high-resolution ultrasound imaging platform, Vevo (VisualSonics, Inc.) provides in vivo, real-time images with exceptional resolution (up to 30 microns) using high-frequency transducers (up to 80 MHz). Recently, we built optoacoustic systems for probing radial artery and peripheral veins that can be used for noninvasive monitoring of total hemoglobin concentration, oxyhemoglobin saturation, and concentration of important endogenous and exogenous chromophores (such as ICG). In this work we used the high-resolution ultrasound imaging system Vevo 770 for visualization of the radial artery and peripheral veins and acquired corresponding optoacoustic signals from them using the optoacoustic systems. Analysis of the optoacoustic data with a specially developed algorithm allowed for measurement of blood oxygenation in the blood vessels as well as for continuous, real-time monitoring of arterial and venous blood oxygenation. Our results indicate that: 1) the optoacoustic technique (unlike pure optical approaches and other noninvasive techniques) is capable of accurate peripheral venous oxygenation measurement; and 2) peripheral venous oxygenation is dependent on skin temperature and local hemodynamics. Moreover, we performed for the first time (to the best of our knowledge) a comparative study of optoacoustic arterial oximetry and a standard pulse oximeter in humans and demonstrated superior performance of the optoacoustic arterial oximeter, in particular at low blood flow.

Performance improvements from imagery:evidence that internal visual imagery is superior to external visual imagery for slalom performance

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Nichola eCallow

2013-10-01

Full Text Available We report three experiments investigating the hypothesis that use of internal visual imagery (IVI would be superior to external visual imagery (EVI for the performance of different slalom-based motor tasks. In Experiment 1, three groups of participants (IVI, EVI, and a control group performed a driving-simulation slalom task. The IVI group achieved significantly quicker lap times than EVI and the control group. In Experiment 2, participants performed a downhill running slalom task under both IVI and EVI conditions. Performance was again quickest in the IVI compared to EVI condition, with no differences in accuracy. Experiment 3 used the same group design as Experiment 1, but with participants performing a downhill ski-slalom task. Results revealed the IVI group to be significantly more accurate than the control group, with no significant differences in time taken to complete the task. These results support the beneficial effects of IVI for slalom-based tasks, and significantly advances our knowledge related to the differential effects of visual imagery perspectives on motor performance.

Classic Peripheral Signs of Subacute Bacterial Endocarditis

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Yooyoung Chong

2016-10-01

Full Text Available A 50-year-old female patient with visual disturbances was referred for further evaluation of a heart murmur. Fundoscopy revealed a Roth spot in both eyes. A physical examination showed peripheral signs of infective endocarditis, including Osler nodes, Janeway lesions, and splinter hemorrhages. Our preoperative diagnosis was subacute bacterial endocarditis with severe aortic regurgitation. The patient underwent aortic valve replacement and was treated with intravenous antibiotics for 6 weeks postoperatively. The patient made a remarkable recovery and was discharged without complications. We report this case of subacute endocarditis with all 4 classic peripheral signs in a patient who presented with visual disturbance.

Classic Peripheral Signs of Subacute Bacterial Endocarditis

Science.gov (United States)

Chong, Yooyoung; Han, Sung Joon; Rhee, Youn Ju; Kang, Shin Kwang; Yu, Jae Hyeon; Na, Myung Hoon

2016-01-01

A 50-year-old female patient with visual disturbances was referred for further evaluation of a heart murmur. Fundoscopy revealed a Roth spot in both eyes. A physical examination showed peripheral signs of infective endocarditis, including Osler nodes, Janeway lesions, and splinter hemorrhages. Our preoperative diagnosis was subacute bacterial endocarditis with severe aortic regurgitation. The patient underwent aortic valve replacement and was treated with intravenous antibiotics for 6 weeks postoperatively. The patient made a remarkable recovery and was discharged without complications. We report this case of subacute endocarditis with all 4 classic peripheral signs in a patient who presented with visual disturbance. PMID:27734006

Recovery of visual-field defects after occipital lobe infarction: a perimetric study.

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Çelebisoy, Mehmet; Çelebisoy, Neşe; Bayam, Ece; Köse, Timur

2011-06-01

To assess the temporal course of homonymous visual-field defects due to occipital lobe infarction, by using automated perimetry. 32 patients with ischaemic infarction of the occipital lobe were studied prospectively, using a Humphrey Visual Field Analyser II. The visual field of each eye was divided into central, paracentral and peripheral zones. The mean visual sensitivity of each zone was calculated and used for the statistical analysis. The results of the initial examination, performed within 2 weeks of stroke, were compared with the results of the sixth-month control. The lesions were assigned to the localisations, optic radiation, striate cortex, occipital pole and occipital convexity, by MRI. A statistically significant improvement was noted, especially for the lower quadrants. Lesions of the occipital pole and convexity were not significantly associated with visual-field recovery. However, involvement of the striate cortex and extensive lesions involving all the areas studied was significantly associated with poor prognosis. Homonymous visual-field defects in our patients improved within 6 months. Restoration of the lower quadrants and especially the peripheral zones was noted. Incomplete damage to the striate cortex, which has a varying pattern of vascular supply, could explain this finding. Magnification factor theory, which is the increment of the receptive-field size of striate cortex cells with visual-field eccentricity, may explain the more significant improvement in the peripheral zones.

Radionuclide lymphoscintigraphy in the evaluation of peripheral edema

International Nuclear Information System (INIS)

Kim, Soon; Zeon, Seok Kil

2000-01-01

It has been difficulty to visualize lymphatics in living patients. Conventional or direct lymphography has been the gold standard for delineation of the lymphatic system, but this procedure is invasive, difficulty to perform, and harmful to the lymphatic vascular endothelium. The aim of our study was to determine its severity, and to understand the drainage patterns on patients with peripheral edema by functional lymphatic studies. Tc-99m antimony sulfide colloid 25 MBq with 0.4 ml volume was injected intradermally in the first, second and third web space of the foot or hand in 40 patients with peripheral edema (5 in upper extremity and 35 in lower extremity). Initial flow after injection and whole body images at approximately 30 minutes. 1-4 hours were obtained. In 9/40 cases with peripheral edema normal lymphoscintigram were revealed, primary lymphedema was observed in 5/31 cases. The imaging patterns in primary lymphedema were absent (3 cases) or delayed (2 cases) transport, lymphatic duct dilatation (1), cutoff (1), decrease in size and number of lymph nodes (2). The Common caused of edema in secondry lymphedema (26/31) were carcinoma (13), inflammation (5), post-operation (5), and unknown origin (3). The common imaging findings in carcinoma showed non-visualization of lymph nodes (13), dermal backflow (8), collateral circulation (5), and in inflammation lymphatic obstruction (2), increase in size and number of lymph nodes (2), delayed transport (1), and in post-operation dermal backflow (3), delayed transport (2), decrease in number and size of lymph node (2) Clear images patterns were observed difference between primary lymphedema an secondary lymphedema. Radionuclide lymphoscintigraphy is essentially non-invasive, easy to perform repeatedly, and harmless to the lymphatic vascular endothelium for evaluation of a patient with lymphedema

The role of peripheral vision in implicit contextual cuing.

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van Asselen, Marieke; Castelo-Branco, Miguel

2009-01-01

Implicit contextual cuing refers to the ability to learn the association between contextual information of our environment and a specific target, which can be used to guide attention during visual search. It was recently suggested that the storage of a snapshot image of the local context of a target underlies implicit contextual cuing. To make such a snapshot, it is necessary to use peripheral vision. In order to test whether peripheral vision can underlie implicit contextual cuing, we used a covert visual search task, in which participants were required to indicate the orientation of a target stimulus while foveating a fixation cross. The response times were shorter when the configuration of the stimuli was repeated than when the configuration was new. Importantly, this effect was still found after 10 days, indicating that peripherally perceived spatial context information can be stored in memory for long periods of time. These results indicate that peripheral vision can be used to make a snapshot of the local context of a target.

Agnosic vision is like peripheral vision, which is limited by crowding.

Science.gov (United States)

Strappini, Francesca; Pelli, Denis G; Di Pace, Enrico; Martelli, Marialuisa

2017-04-01

Visual agnosia is a neuropsychological impairment of visual object recognition despite near-normal acuity and visual fields. A century of research has provided only a rudimentary account of the functional damage underlying this deficit. We find that the object-recognition ability of agnosic patients viewing an object directly is like that of normally-sighted observers viewing it indirectly, with peripheral vision. Thus, agnosic vision is like peripheral vision. We obtained 14 visual-object-recognition tests that are commonly used for diagnosis of visual agnosia. Our "standard" normal observer took these tests at various eccentricities in his periphery. Analyzing the published data of 32 apperceptive agnosia patients and a group of 14 posterior cortical atrophy (PCA) patients on these tests, we find that each patient's pattern of object recognition deficits is well characterized by one number, the equivalent eccentricity at which our standard observer's peripheral vision is like the central vision of the agnosic patient. In other words, each agnosic patient's equivalent eccentricity is conserved across tests. Across patients, equivalent eccentricity ranges from 4 to 40 deg, which rates severity of the visual deficit. In normal peripheral vision, the required size to perceive a simple image (e.g., an isolated letter) is limited by acuity, and that for a complex image (e.g., a face or a word) is limited by crowding. In crowding, adjacent simple objects appear unrecognizably jumbled unless their spacing exceeds the crowding distance, which grows linearly with eccentricity. Besides conservation of equivalent eccentricity across object-recognition tests, we also find conservation, from eccentricity to agnosia, of the relative susceptibility of recognition of ten visual tests. These findings show that agnosic vision is like eccentric vision. Whence crowding? Peripheral vision, strabismic amblyopia, and possibly apperceptive agnosia are all limited by crowding, making it

Mobility scooter driving ability in visually impaired individuals.

Science.gov (United States)

Cordes, Christina; Heutink, Joost; Brookhuis, Karel A; Brouwer, Wiebo H; Melis-Dankers, Bart J M

2018-06-01

To investigate how well visually impaired individuals can learn to use mobility scooters and which parts of the driving task deserve special attention. A mobility scooter driving skill test was developed to compare driving skills (e.g. reverse driving, turning) between 48 visually impaired (very low visual acuity = 14, low visual acuity = 10, peripheral field defects = 11, multiple visual impairments = 13) and 37 normal-sighted controls without any prior experience with mobility scooters. Performance on this test was rated on a three-point scale. Furthermore, the number of extra repetitions on the different elements were noted. Results showed that visually impaired participants were able to gain sufficient driving skills to be able to use mobility scooters. Participants with visual field defects combined with low visual acuity showed most problems learning different skills and needed more training. Reverse driving and stopping seemed to be most difficult. The present findings suggest that visually impaired individuals are able to learn to drive mobility scooters. Mobility scooter allocators should be aware that these individuals might need more training on certain elements of the driving task. Implications for rehabilitation Visual impairments do not necessarily lead to an inability to acquire mobility scooter driving skills. Individuals with peripheral field defects (especially in combination with reduced visual acuity) need more driving ability training compared to normal-sighted people - especially to accomplish reversing. Individual assessment of visually impaired people is recommended, since participants in this study showed a wide variation in ability to learn driving a mobility scooter.

Training improves reading speed in peripheral vision: is it due to attention?

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Lee, Hye-Won; Kwon, Miyoung; Legge, Gordon E; Gefroh, Joshua J

2010-06-01

Previous research has shown that perceptual training in peripheral vision, using a letter-recognition task, increases reading speed and letter recognition (S. T. L. Chung, G. E. Legge, & S. H. Cheung, 2004). We tested the hypothesis that enhanced deployment of spatial attention to peripheral vision explains this training effect. Subjects were pre- and post-tested with 3 tasks at 10° above and below fixation-RSVP reading speed, trigram letter recognition (used to construct visual-span profiles), and deployment of spatial attention (measured as the benefit of a pre-cue for target position in a lexical-decision task). Groups of five normally sighted young adults received 4 days of trigram letter-recognition training in upper or lower visual fields, or central vision. A control group received no training. Our measure of deployment of spatial attention revealed visual-field anisotropies; better deployment of attention in the lower field than the upper, and in the lower-right quadrant compared with the other three quadrants. All subject groups exhibited slight improvement in deployment of spatial attention to peripheral vision in the post-test, but this improvement was not correlated with training-related increases in reading speed and the size of visual-span profiles. Our results indicate that improved deployment of spatial attention to peripheral vision does not account for improved reading speed and letter recognition in peripheral vision.

Higher-order neural processing tunes motion neurons to visual ecology in three species of hawkmoths.

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Stöckl, A L; O'Carroll, D; Warrant, E J

2017-06-28

To sample information optimally, sensory systems must adapt to the ecological demands of each animal species. These adaptations can occur peripherally, in the anatomical structures of sensory organs and their receptors; and centrally, as higher-order neural processing in the brain. While a rich body of investigations has focused on peripheral adaptations, our understanding is sparse when it comes to central mechanisms. We quantified how peripheral adaptations in the eyes, and central adaptations in the wide-field motion vision system, set the trade-off between resolution and sensitivity in three species of hawkmoths active at very different light levels: nocturnal Deilephila elpenor, crepuscular Manduca sexta , and diurnal Macroglossum stellatarum. Using optical measurements and physiological recordings from the photoreceptors and wide-field motion neurons in the lobula complex, we demonstrate that all three species use spatial and temporal summation to improve visual performance in dim light. The diurnal Macroglossum relies least on summation, but can only see at brighter intensities. Manduca, with large sensitive eyes, relies less on neural summation than the smaller eyed Deilephila , but both species attain similar visual performance at nocturnal light levels. Our results reveal how the visual systems of these three hawkmoth species are intimately matched to their visual ecologies. © 2017 The Author(s).

Macular pigment and visual performance in glare: benefits for photostress recovery, disability glare, and visual discomfort.

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Stringham, James M; Garcia, Paul V; Smith, Peter A; McLin, Leon N; Foutch, Brian K

2011-09-22

One theory of macular pigment's (MP) presence in the fovea is to improve visual performance in glare. This study sought to determine the effect of MP level on three aspects of visual performance in glare: photostress recovery, disability glare, and visual discomfort. Twenty-six subjects participated in the study. Spatial profiles of MP optical density were assessed with heterochromatic flicker photometry. Glare was delivered via high-bright-white LEDs. For the disability glare and photostress recovery portions of the experiment, the visual task consisted of correct identification of a 1° Gabor patch's orientation. Visual discomfort during the glare presentation was assessed with a visual discomfort rating scale. Pupil diameter was monitored with an infrared (IR) camera. MP level correlated significantly with all the outcome measures. Higher MP optical densities (MPODs) resulted in faster photostress recovery times (average P disability glare contrast thresholds (average P visual discomfort (P = 0.002). Smaller pupil diameter during glare presentation significantly correlated with higher visual discomfort ratings (P = 0.037). MP correlates with three aspects of visual performance in glare. Unlike previous studies of MP and glare, the present study used free-viewing conditions, in which effects of iris pigmentation and pupil size could be accounted for. The effects described, therefore, can be extended more confidently to real-world, practical visual performance benefits. Greater iris constriction resulted (paradoxically) in greater visual discomfort. This finding may be attributable to the neurobiologic mechanism that mediates the pain elicited by light.

Optical coherent tomography in diagnoses of peripheral retinal degenarations

OpenAIRE

O. G. Pozdeyeva; T. B. Shaimov; A. Yu. Galin; R. B. Shaimov; T. A. Shaimova; A. V. Zolotova; A. V. Fomin

2014-01-01

Purpose: Studying the capabilities of optical coherence tomography (RTVue-100, OPTOVUE, USA) in evaluation of peripheral retinal degenerations, vitreoretinal adhesions, adjacent vitreous body as well as measurement of morphometric data.Methods: The study included 189 patients (239 eyes) with peripheral retinal degeneration. 77 men and 112 women aged 18 to 84 underwent an ophthalmologic examination since November 2012 until October 2013. The peripheral retina was visualized with the help of op...

Unconsciously perceived fear in peripheral vision alerts the limbic system: a MEG study.

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Dimitri J Bayle

Full Text Available BACKGROUND: In ecological situations, threatening stimuli often come out from the peripheral vision. Such aggressive messages must trigger rapid attention to the periphery to allow a fast and adapted motor reaction. Several clues converge to hypothesize that peripheral danger presentation can trigger off a fast arousal network potentially independent of the consciousness spot. METHODOLOGY/PRINCIPAL FINDINGS: In the present MEG study, spatio-temporal dynamics of the neural processing of danger related stimuli were explored as a function of the stimuli position in the visual field. Fearful and neutral faces were briefly presented in the central or peripheral visual field, and were followed by target faces stimuli. An event-related beamformer source analysis model was applied in three time windows following the first face presentations: 80 to 130 ms, 140 to 190 ms, and 210 to 260 ms. The frontal lobe and the right internal temporal lobe part, including the amygdala, reacted as soon as 80 ms of latency to fear occurring in the peripheral vision. For central presentation, fearful faces evoked the classical neuronal activity along the occipito-temporal visual pathway between 140 and 190 ms. CONCLUSIONS: Thus, the high spatio-temporal resolution of MEG allowed disclosing a fast response of a network involving medial temporal and frontal structures in the processing of fear related stimuli occurring unconsciously in the peripheral visual field. Whereas centrally presented stimuli are precisely processed by the ventral occipito-temporal cortex, the related-to-danger stimuli appearing in the peripheral visual field are more efficient to produce a fast automatic alert response possibly conveyed by subcortical structures.

Adaptive Performance-Constrained in Situ Visualization of Atmospheic Simulations

Energy Technology Data Exchange (ETDEWEB)

Dorier, Matthieu; Sisneros, Roberto; Bautista Gomez, Leonard; Peterka, Tom; Orf, Leigh; Rahmani, Lokman; Antoniu, Gabriel; Bouge, Luc

2016-09-12

While many parallel visualization tools now provide in situ visualization capabilities, the trend has been to feed such tools with large amounts of unprocessed output data and let them render everything at the highest possible resolution. This leads to an increased run time of simulations that still have to complete within a fixed-length job allocation. In this paper, we tackle the challenge of enabling in situ visualization under performance constraints. Our approach shuffles data across processes according to its content and filters out part of it in order to feed a visualization pipeline with only a reorganized subset of the data produced by the simulation. Our framework leverages fast, generic evaluation procedures to score blocks of data, using information theory, statistics, and linear algebra. It monitors its own performance and adapts dynamically to achieve appropriate visual fidelity within predefined performance constraints. Experiments on the Blue Waters supercomputer with the CM1 simulation show that our approach enables a 5 speedup with respect to the initial visualization pipeline and is able to meet performance constraints.

Perceptual load in different regions of the visual scene and its relevance for driving.

Science.gov (United States)

Marciano, Hadas; Yeshurun, Yaffa

2015-06-01

The aim of this study was to better understand the role played by perceptual load, at both central and peripheral regions of the visual scene, in driving safety. Attention is a crucial factor in driving safety, and previous laboratory studies suggest that perceptual load is an important factor determining the efficiency of attentional selectivity. Yet, the effects of perceptual load on driving were never studied systematically. Using a driving simulator, we orthogonally manipulated the load levels at the road (central load) and its sides (peripheral load), while occasionally introducing critical events at one of these regions. Perceptual load affected driving performance at both regions of the visual scene. Critically, the effect was different for central versus peripheral load: Whereas load levels on the road mainly affected driving speed, load levels on its sides mainly affected the ability to detect critical events initiating from the roadsides. Moreover, higher levels of peripheral load impaired performance but mainly with low levels of central load, replicating findings with simple letter stimuli. Perceptual load has a considerable effect on driving, but the nature of this effect depends on the region of the visual scene at which the load is introduced. Given the observed importance of perceptual load, authors of future studies of driving safety should take it into account. Specifically, these findings suggest that our understanding of factors that may be relevant for driving safety would benefit from studying these factors under different levels of load at different regions of the visual scene. © 2014, Human Factors and Ergonomics Society.

Visualization and Data Analysis for High-Performance Computing

Energy Technology Data Exchange (ETDEWEB)

Sewell, Christopher Meyer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-09-27

This is a set of slides from a guest lecture for a class at the University of Texas, El Paso on visualization and data analysis for high-performance computing. The topics covered are the following: trends in high-performance computing; scientific visualization, such as OpenGL, ray tracing and volume rendering, VTK, and ParaView; data science at scale, such as in-situ visualization, image databases, distributed memory parallelism, shared memory parallelism, VTK-m, "big data", and then an analysis example.

Peripheral vision and perceptual asymmetries in young and older martial arts athletes and nonathletes.

Science.gov (United States)

Muiños, Mónica; Ballesteros, Soledad

2014-11-01

The present study investigated peripheral vision (PV) and perceptual asymmetries in young and older martial arts athletes (judo and karate athletes) and compared their performance with that of young and older nonathletes. Stimuli were dots presented at three different eccentricities along the horizontal, oblique, and vertical diameters and three interstimulus intervals. Experiment 1 showed that although the two athlete groups were faster in almost all conditions, karate athletes performed significantly better than nonathlete participants when stimuli were presented in the peripheral visual field. Experiment 2 showed that older participants who had practiced a martial art at a competitive level when they were young were significantly faster than sedentary older adults of the same age. The practiced sport (judo or karate) did not affect performance differentially, suggesting that it is the practice of martial arts that is the crucial factor, rather than the type of martial art. Importantly, older athletes lose their PV advantage, as compared with young athletes. Finally, we found that physical activity (young and older athletes) and age (young and older adults) did not alter the visual asymmetries that vary as a function of spatial location; all participants were faster for stimuli presented along the horizontal than for those presented along the vertical meridian and for those presented at the lower rather than at the upper locations within the vertical meridian. These results indicate that the practice of these martial arts is an effective way of counteracting the processing speed decline of visual stimuli appearing at any visual location and speed.

Effects of visual attention on chromatic and achromatic detection sensitivities.

Science.gov (United States)

Uchikawa, Keiji; Sato, Masayuki; Kuwamura, Keiko

2014-05-01

Visual attention has a significant effect on various visual functions, such as response time, detection and discrimination sensitivity, and color appearance. It has been suggested that visual attention may affect visual functions in the early visual pathways. In this study we examined selective effects of visual attention on sensitivities of the chromatic and achromatic pathways to clarify whether visual attention modifies responses in the early visual system. We used a dual task paradigm in which the observer detected a peripheral test stimulus presented at 4 deg eccentricities while the observer concurrently carried out an attention task in the central visual field. In experiment 1, it was confirmed that peripheral spectral sensitivities were reduced more for short and long wavelengths than for middle wavelengths with the central attention task so that the spectral sensitivity function changed its shape by visual attention. This indicated that visual attention affected the chromatic response more strongly than the achromatic response. In experiment 2 it was obtained that the detection thresholds increased in greater degrees in the red-green and yellow-blue chromatic directions than in the white-black achromatic direction in the dual task condition. In experiment 3 we showed that the peripheral threshold elevations depended on the combination of color-directions of the central and peripheral stimuli. Since the chromatic and achromatic responses were separately processed in the early visual pathways, the present results provided additional evidence that visual attention affects responses in the early visual pathways.

Substantial adverse association of visual and vascular comorbidities on visual disability in multiple sclerosis.

Science.gov (United States)

Marrie, Ruth Ann; Cutter, Gary; Tyry, Tuula

2011-12-01

Visual comorbidities are common in multiple sclerosis (MS) but the impact of visual comorbidities on visual disability is unknown. We assessed the impact of visual and vascular comorbidities on severity of visual disability in MS. In 2006, we queried participants of the North American Research Committee on Multiple Sclerosis (NARCOMS) about cataracts, glaucoma, uveitis, hypertension, hypercholesterolemia, heart disease, diabetes and peripheral vascular disease. We assessed visual disability using the Vision subscale of Performance Scales. Using Cox regression, we investigated whether visual or vascular comorbidities affected the time between MS symptom onset and the development of mild, moderate and severe visual disability. Of 8983 respondents, 1415 (15.9%) reported a visual comorbidity while 4745 (52.8%) reported a vascular comorbidity. The median (interquartile range) visual score was 1 (0-2). In a multivariable Cox model the risk of mild visual disability was higher among participants with vascular (hazard ratio [HR] 1.45; 95% confidence interval [CI]: 1.39-1.51) and visual comorbidities (HR 1.47; 95% CI: 1.37-1.59). Vascular and visual comorbidities were similarly associated with increased risks of moderate and severe visual disability. Visual and vascular comorbidities are associated with progression of visual disability in MS. Clinicians hearing reports of worsening visual symptoms in MS patients should consider visual comorbidities as contributing factors. Further study of these issues using objective, systematic neuro-ophthalmologic evaluations is warranted.

Balance rehabilitation: promoting the role of virtual reality in patients with diabetic peripheral neuropathy.

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Grewal, Gurtej S; Sayeed, Rashad; Schwenk, Michael; Bharara, Manish; Menzies, Robert; Talal, Talal K; Armstrong, David G; Najafi, Bijan

2013-01-01

Individuals with diabetic peripheral neuropathy frequently experience concomitant impaired proprioception and postural instability. Conventional exercise training has been demonstrated to be effective in improving balance but does not incorporate visual feedback targeting joint perception, which is an integral mechanism that helps compensate for impaired proprioception in diabetic peripheral neuropathy. This prospective cohort study recruited 29 participants (mean ± SD: age, 57 ± 10 years; body mass index [calculated as weight in kilograms divided by height in meters squared], 26.9 ± 3.1). Participants satisfying the inclusion criteria performed predefined ankle exercises through reaching tasks, with visual feedback from the ankle joint projected on a screen. Ankle motion in the mediolateral and anteroposterior directions was captured using wearable sensors attached to the participant's shank. Improvements in postural stability were quantified by measuring center of mass sway area and the reciprocal compensatory index before and after training using validated body-worn sensor technology. Findings revealed a significant reduction in center of mass sway after training (mean, 22%; P = .02). A higher postural stability deficit (high body sway) at baseline was associated with higher training gains in postural balance (reduction in center of mass sway) (r = -0.52, P virtual reality technology. The method included wearable sensors and an interactive user interface for real-time visual feedback based on ankle joint motion, similar to a video gaming environment, for compensating impaired joint proprioception. These findings support that visual feedback generated from the ankle joint coupled with motor learning may be effective in improving postural stability in patients with diabetic peripheral neuropathy.

Near-infrared vascular imaging in peripheral venous and arterial access

OpenAIRE

Cuper, N.J.

2012-01-01

Venous and arterial access are among the most widespread medical procedures performed in children. Especially in young children venous and arterial access can be problematic due to tiny blood vessels that are difficult to localize beneath a layer of baby fat. This thesis describes the development and clinical evaluation of the VascuLuminator, a guidance tool for peripheral venous and arterial access by visualizing blood vessels underneath the skin with near-infrared light. In a third to a fif...

Ultrasonographic evaluation of the iatrogenic peripheral nerve injuries in upper extremity

International Nuclear Information System (INIS)

Karabay, Nuri; Toros, Tulgar; Ademoglu, Yalcin; Ada, Sait

2010-01-01

The aim of our study is to assess the efficiency of the ultrasonography (US) in the diagnosis of peripheral nerve injury. This study includes nine patients (six radial, one median and two posterior interosseous (PIO) nerves) with peripheral nerve injury diagnosed by clinical and electrophysiological methods in the last 3 years. Preoperatively, an ultrasonographic examination was performed and correlated with physical exam and surgical findings. Five patients, who were diagnosed as peripheral nerve transection by US, underwent surgery. The ultrasonographic findings were concordant with the intraoperative findings. Axonal swelling alone was found in the remaining three patients, who were treated conservatively because of preserved nerve continuity without display of nerve compression. In one patient, we were unable to visualize the nerve due to obesity and soft tissue edema. High-resolution US provide morphological information about the exact location, intensity and extent of the nerve injuries, facilitating the preoperative diagnosis. Thus, US may be a useful method for planning optimal treatment strategy in especially iatrogenic nerve injuries.

Ultrasonographic evaluation of the iatrogenic peripheral nerve injuries in upper extremity

Energy Technology Data Exchange (ETDEWEB)

Karabay, Nuri [Department of Radiology, Hand and Microsurgery and Orthopaedics and Traumatology (EMOT) Hospital, 1418 Sok. No: 14 Kahramanlar, 35230 Izmir (Turkey)], E-mail: nurikarabay@gmail.com; Toros, Tulgar [Department of Orthopaedics and Traumatology, Hand and Microsurgery and Orthopaedics and Traumatology (EMOT) Hospital, 1418 Sok. No: 14 Kahramanlar, 35230 Izmir (Turkey)], E-mail: tulgartoros@yahoo.com; Ademoglu, Yalcin [Department of Orthopaedics and Traumatology, Hand and Microsurgery and Orthopaedics and Traumatology (EMOT) Hospital, 1418 Sok. No: 14 Kahramanlar, 35230 Izmir (Turkey)], E-mail: yalcinademoglu@yahoo.com; Ada, Sait [Department of Orthopaedics and Traumatology, Hand and Microsurgery and Orthopaedics and Traumatology (EMOT) Hospital, 1418 Sok. No: 14 Kahramanlar, 35230 Izmir (Turkey)], E-mail: sait_ada@yahoo.com

2010-02-15

The aim of our study is to assess the efficiency of the ultrasonography (US) in the diagnosis of peripheral nerve injury. This study includes nine patients (six radial, one median and two posterior interosseous (PIO) nerves) with peripheral nerve injury diagnosed by clinical and electrophysiological methods in the last 3 years. Preoperatively, an ultrasonographic examination was performed and correlated with physical exam and surgical findings. Five patients, who were diagnosed as peripheral nerve transection by US, underwent surgery. The ultrasonographic findings were concordant with the intraoperative findings. Axonal swelling alone was found in the remaining three patients, who were treated conservatively because of preserved nerve continuity without display of nerve compression. In one patient, we were unable to visualize the nerve due to obesity and soft tissue edema. High-resolution US provide morphological information about the exact location, intensity and extent of the nerve injuries, facilitating the preoperative diagnosis. Thus, US may be a useful method for planning optimal treatment strategy in especially iatrogenic nerve injuries.

Visual functions and disability in diabetic retinopathy patients.

Science.gov (United States)

Shrestha, Gauri Shankar; Kaiti, Raju

2014-01-01

This study was undertaken to find correlations between visual functions and visual disabilities in patients with diabetic retinopathy. A cross-sectional study was carried out among 38 visually impaired diabetic retinopathy subjects at the Low Vision Clinic of B.P. Koirala Lions Centre for Ophthalmic Studies, Kathmandu. The subjects underwent assessment of distance and near visual acuity, objective and subjective refraction, contrast sensitivity, color vision, and central and peripheral visual fields. The visual disabilities of each subject in their daily lives were evaluated using a standard questionnaire. Multiple regression analysis between visual functions and visual disabilities index was assessed. The majority of subjects (42.1%) were of the age group 60-70 years. Best corrected visual acuity was found to be 0.73±0.2 in the better eye and 0.93±0.27 in the worse eye, which was significantly different at p=0.002. Visual disability scores were significantly higher for legibility of letters (1.2±0.3) and sentences (1.4±0.4), and least for clothing (0.7±0.3). Visual disability index for legibility of letters and sentences was significantly correlated with near visual acuity and peripheral visual field. Contrast sensitivity was also significantly correlated with the visual disability index, and total scores. Impairment of near visual acuity, contrast sensitivity, and peripheral visual field correlated significantly with different types of visual disability. Hence, these clinical tests should be an integral part of the visual assessment of diabetic eyes. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Visual functions and disability in diabetic retinopathy patients

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Gauri Shankar Shrestha

2014-01-01

Conclusion: Impairment of near visual acuity, contrast sensitivity, and peripheral visual field correlated significantly with different types of visual disability. Hence, these clinical tests should be an integral part of the visual assessment of diabetic eyes.

Application of blood-pool agents in visualization of peripheral vessels

International Nuclear Information System (INIS)

Giovagnoni, A.; Catalano, C.

2007-01-01

Effective arterial imaging is essential in patients with peripheral arterial disease (PAD) in whom a revascularization procedure is planned. Digital subtraction angiography (DSA) has traditionally been regarded as the gold standard for imaging in peripheral arterial disease, but this technique is subject to certain limitations, such as the risks of adverse reactions associated with arterial catheterization and iodinated contrast agents. Contrast-enhanced magnetic resonance angiography is now recommended as an effective and useful imaging technique in peripheral arterial disease, since it offers high enhanced contrast between blood and stationary tissue and fast acquisition times. However, extracellular gadolinium contrast agents rapidly diffuse into the interstitial spaces, and thus are suitable only for first-pass imaging. This limitation can be overcome by the use of blood-pool (intravascular) contrast agents, such as gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany), which are retained within the blood vessels and hence facilitate both first-pass and steady-state imaging with high spatial resolution. Blood-pool agents, therefore, offer improved imaging, particularly of distal vessels, compared with extracellular contrast agents. Examples of first-pass and steady-state imaging with gadofosveset are presented. (orig.)

Visual Search Performance in Patients with Vision Impairment: A Systematic Review.

Science.gov (United States)

Senger, Cassia; Margarido, Maria Rita Rodrigues Alves; De Moraes, Carlos Gustavo; De Fendi, Ligia Issa; Messias, André; Paula, Jayter Silva

2017-11-01

Patients with visual impairment are constantly facing challenges to achieve an independent and productive life, which depends upon both a good visual discrimination and search capacities. Given that visual search is a critical skill for several daily tasks and could be used as an index of the overall visual function, we investigated the relationship between vision impairment and visual search performance. A comprehensive search was undertaken using electronic PubMed, EMBASE, LILACS, and Cochrane databases from January 1980 to December 2016, applying the following terms: "visual search", "visual search performance", "visual impairment", "visual exploration", "visual field", "hemianopia", "search time", "vision lost", "visual loss", and "low vision". Two hundred seventy six studies from 12,059 electronic database files were selected, and 40 of them were included in this review. Studies included participants of all ages, both sexes, and the sample sizes ranged from 5 to 199 participants. Visual impairment was associated with worse visual search performance in several ophthalmologic conditions, which were either artificially induced, or related to specific eye and neurological diseases. This systematic review details all the described circumstances interfering with visual search tasks, highlights the need for developing technical standards, and outlines patterns for diagnosis and therapy using visual search capabilities.

VISUAL ART TEACHERS AND PERFORMANCE ASSESSMENT ...

African Journals Online (AJOL)

Charles

Senior Secondary school visual art teachers constituted the sample of this ... and Performance Assessment Methods in Nigerian Senior Secondary Schools – Bello .... definition includes knowledge, skills, attitudes, metacognition and strategic ...

Foveal and peripheral fields of vision influences perceptual skill in anticipating opponents' attacking position in volleyball.

Science.gov (United States)

Schorer, Jörg; Rienhoff, Rebecca; Fischer, Lennart; Baker, Joseph

2013-09-01

The importance of perceptual-cognitive expertise in sport has been repeatedly demonstrated. In this study we examined the role of different sources of visual information (i.e., foveal versus peripheral) in anticipating volleyball attack positions. Expert (n = 11), advanced (n = 13) and novice (n = 16) players completed an anticipation task that involved predicting the location of volleyball attacks. Video clips of volleyball attacks (n = 72) were spatially and temporally occluded to provide varying amounts of information to the participant. In addition, participants viewed the attacks under three visual conditions: full vision, foveal vision only, and peripheral vision only. Analysis of variance revealed significant between group differences in prediction accuracy with higher skilled players performing better than lower skilled players. Additionally, we found significant differences between temporal and spatial occlusion conditions. Both of those factors interacted separately, but not combined with expertise. Importantly, for experts the sum of both fields of vision was superior to either source in isolation. Our results suggest different sources of visual information work collectively to facilitate expert anticipation in time-constrained sports and reinforce the complexity of expert perception.

Creating social presence through peripheral awareness

NARCIS (Netherlands)

Ruyter, de B.E.R.; Huijnen, C.A.G.J.; Markopoulos, P.; IJsselsteijn, W.A.; Stephanidis, C.; Jacko, J.

2003-01-01

This paper describes an experimental assessment of affective user benefits that may result from peripheral awareness of a remote friend or group of friends during a shared viewing of a televised event. The experiment suggests that awareness supported through a visual display enhances the level of

Optical coherent tomography in diagnoses of peripheral retinal degenarations

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O. G. Pozdeyeva

2013-01-01

Full Text Available Purpose: Studying the capabilities of optical coherence tomography (RTVue-100, OPTOVUE, USA in evaluation of peripheral retinal degenerations, vitreoretinal adhesions, adjacent vitreous body as well as measurement of morphometric data.Methods: The study included 189 patients (239 eyes with peripheral retinal degeneration. 77 men and 112 women aged 18 to 84 underwent an ophthalmologic examination since November 2012 until October 2013. The peripheral retina was visualized with the help of optical coherence tomography («RTVue-100,» USA. The fundography was carried out using a Nikon NF505‑AF (Japan fundus camera. All patients were examined with a Goldmann lens.Results: Optical coherence tomography was used to evaluate different kinds of peripheral retinal degenerations, such as lattice and snail track degeneration, isolated retinal tears, cystoid retinal degeneration, pathological hyperpigmentation, retinoschisis and cobblestone degeneration. The following morphometric data were studied: dimensions of the lesion (average length, retinal thickness along the edge of the lesion, retinal thickness at the base of the lesion and the vitreoretinal interface.Conclusion: Optical coherence tomography is a promising in vivo visualization method which is useful in evaluation of peripheral retinal degenerations, vitreoretinal adhesions and tractions. It also provides a comprehensive protocolling system and monitoring. It will enable ophthalmologists to better define laser and surgical treatment indications and evaluate therapy effectiveness.

Optical coherent tomography in diagnoses of peripheral retinal degenarations

Directory of Open Access Journals (Sweden)

O. G. Pozdeyeva

2014-07-01

Full Text Available Purpose: Studying the capabilities of optical coherence tomography (RTVue-100, OPTOVUE, USA in evaluation of peripheral retinal degenerations, vitreoretinal adhesions, adjacent vitreous body as well as measurement of morphometric data.Methods: The study included 189 patients (239 eyes with peripheral retinal degeneration. 77 men and 112 women aged 18 to 84 underwent an ophthalmologic examination since November 2012 until October 2013. The peripheral retina was visualized with the help of optical coherence tomography («RTVue-100,» USA. The fundography was carried out using a Nikon NF505‑AF (Japan fundus camera. All patients were examined with a Goldmann lens.Results: Optical coherence tomography was used to evaluate different kinds of peripheral retinal degenerations, such as lattice and snail track degeneration, isolated retinal tears, cystoid retinal degeneration, pathological hyperpigmentation, retinoschisis and cobblestone degeneration. The following morphometric data were studied: dimensions of the lesion (average length, retinal thickness along the edge of the lesion, retinal thickness at the base of the lesion and the vitreoretinal interface.Conclusion: Optical coherence tomography is a promising in vivo visualization method which is useful in evaluation of peripheral retinal degenerations, vitreoretinal adhesions and tractions. It also provides a comprehensive protocolling system and monitoring. It will enable ophthalmologists to better define laser and surgical treatment indications and evaluate therapy effectiveness.

Auditory, visual and auditory-visual memory and sequencing performance in typically developing children.

Science.gov (United States)

Pillai, Roshni; Yathiraj, Asha

2017-09-01

The study evaluated whether there exists a difference/relation in the way four different memory skills (memory score, sequencing score, memory span, & sequencing span) are processed through the auditory modality, visual modality and combined modalities. Four memory skills were evaluated on 30 typically developing children aged 7 years and 8 years across three modality conditions (auditory, visual, & auditory-visual). Analogous auditory and visual stimuli were presented to evaluate the three modality conditions across the two age groups. The children obtained significantly higher memory scores through the auditory modality compared to the visual modality. Likewise, their memory scores were significantly higher through the auditory-visual modality condition than through the visual modality. However, no effect of modality was observed on the sequencing scores as well as for the memory and the sequencing span. A good agreement was seen between the different modality conditions that were studied (auditory, visual, & auditory-visual) for the different memory skills measures (memory scores, sequencing scores, memory span, & sequencing span). A relatively lower agreement was noted only between the auditory and visual modalities as well as between the visual and auditory-visual modality conditions for the memory scores, measured using Bland-Altman plots. The study highlights the efficacy of using analogous stimuli to assess the auditory, visual as well as combined modalities. The study supports the view that the performance of children on different memory skills was better through the auditory modality compared to the visual modality. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficacy of Tectonic Corneal Patch Graft for Progressive Peripheral Corneal Thinning

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Cafer Tanrıverdio

2014-12-01

Full Text Available Objectives: To report the results of tectonic corneal patch graft (TCPG in patients with progressive peripheral corneal thinning (PCT. Materials and Methods: In this study, we included 8 patients who underwent TCPG for PCT or perforated corneal ulceration at Ankara Training and Research Hospital. Results: We performed TCPG in 7 patients for PCT and in 1 patient for perforated corneal ulceration. Mean age was 57.2±16.7 (38- 82 years. Postoperative follow-up time ranged from 6 to 24 months (mean 13.9±6.7. Possible etiologies leading to progressive PCT were trachoma, infectious corneal ulcer, and rheumatoid arthritis-severe dry eye in 2 patients each. Other 2 patients had a progressive PCT following ocular surgery. One of the patients with infectious corneal ulcer also had a trauma caused by a scissor. Amnion membrane transplantation was performed in 3 patients prior to TCPG. While the anatomic success was achieved in all 8 patients, best-corrected visual acuity (BCVA was 0.1 or better in 4 patients (50%. Postoperative BCVA was better than preoperative BCVA in 6 patients (75%. Local peripheral anterior synechiae developed in two eyes. Conclusion: TCPG is a useful therapeutic option in selected cases of corneal thinning and perforations because it effectively restores the integrity of the globe and allows acceptable visual results. (Turk J Ophthalmol 2014; 44: 440-4

Two-stage perceptual learning to break visual crowding.

Science.gov (United States)

Zhu, Ziyun; Fan, Zhenzhi; Fang, Fang

2016-01-01

When a target is presented with nearby flankers in the peripheral visual field, it becomes harder to identify, which is referred to as crowding. Crowding sets a fundamental limit of object recognition in peripheral vision, preventing us from fully appreciating cluttered visual scenes. We trained adult human subjects on a crowded orientation discrimination task and investigated whether crowding could be completely eliminated by training. We discovered a two-stage learning process with this training task. In the early stage, when the target and flankers were separated beyond a certain distance, subjects acquired a relatively general ability to break crowding, as evidenced by the fact that the breaking of crowding could transfer to another crowded orientation, even a crowded motion stimulus, although the transfer to the opposite visual hemi-field was weak. In the late stage, like many classical perceptual learning effects, subjects' performance gradually improved and showed specificity to the trained orientation. We also found that, when the target and flankers were spaced too finely, training could only reduce, rather than completely eliminate, the crowding effect. This two-stage learning process illustrates a learning strategy for our brain to deal with the notoriously difficult problem of identifying peripheral objects in clutter. The brain first learned to solve the "easy and general" part of the problem (i.e., improving the processing resolution and segmenting the target and flankers) and then tackle the "difficult and specific" part (i.e., refining the representation of the target).

Influence of anaerobic physical effort in the horizontal and vertical peripheral view INFLUENCIA DEL ESFUERZO FÍSICO ANAERÓBICO EN LA VISIÓN PERIFÉRICA VERTICAL Y HORIZONTAL

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M. Arteaga

2010-09-01

Full Text Available

There now seems to be a generalized tendency to consider that sporting performance declines as the sportsperson becomes fatigued. However, there is little empirical evidence to show that this adversely affects visual function. In some sports it is necessary to see stimuli in zones peripheral to central vision. The aim of this study is to analyze the influence of anaerobic exertion on vertical and horizontal Peripheral Vision. An intra-subject design was used with 14 replications. The visual parameters of Vertical Peripheral Vision and Horizontal Peripheral Vision were measured in different fatigue conditions to analyze the possible negative influence which this could exert on the subject’s visual capacity. The results show that fatigue due to anaerobic effort does not harm the visual abilities studied.
KEY WORDS: Peripheral Vision, Fatigue, Anaerobic exertion, Visual abilities

Parece haber una tendencia generalizada a considerar que el rendimiento deportivo disminuye en la medida en que los deportistas acumulan fatiga; sin embargo existen pocas evidencias empíricas que indiquen que la función visual se vea perjudicada por este motivo. En algunos deportes es necesario observar estímulos en zonas periféricas a la visión central. En el presente estudio se pretende analizar la influencia de los esfuerzos anaeeróbicos sobre la Visión Periférica (vertical y horizontal. Se utilizó un diseño intrasujeto A-(B1,B2-A con catorce replicaciones. Se realizaron mediciones de los parámetros visuales: Visión Periférica Vertical y Visión Periférica Horizontal en diferentes condiciones de fatiga para analizar la posible influencia negativa que pudiera ejercer ésta sobre la capacidad visual de los sujetos. Los resultados permiten afirmar que la fatiga debida a esfuerzos de tipo anaeróbico no producen un perjuicio sobre las habilidades visuales estudiadas.
PALABRAS CLAVE: Visi

VISUAL ART TEACHERS AND PERFORMANCE ASSESSMENT ...

African Journals Online (AJOL)

Charles

qualitative research design; an aspect of descriptive survey research aiming at ... the competence and use of assessment strategies is determined by the type of ... Visual Art Teachers and Performance Assessment Methods in Nigerian Senior ...

Rapid intracerebroventricular delivery of Cu-DOTA-etanercept after peripheral administration demonstrated by PET imaging

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Chen Xiaoyuan

2009-02-01

Full Text Available Abstract Background The cytokines interleukin-1 and tumor necrosis factor (TNF, and the cytokine blocker interleukin-1 receptor antagonist, all have been demonstrated to enter the cerebrospinal fluid (CSF following peripheral administration. Recent reports of rapid clinical improvement in patients with Alzheimer's disease and related forms of dementia following perispinal administration of etanercept, a TNF antagonist, suggest that etanercept also has the ability to reach the brain CSF. To investigate, etanercept was labeled with a positron emitter to enable visualization of its intracranial distribution following peripheral administration by PET in an animal model. Findings Radiolabeling of etanercept with the PET emitter 64Cu was performed by DOTA (1,4,7,10-tetraazadodecane-N,N',N",N"'-tetraacetic acid conjugation of etanercept, followed by column purification and 64Cu labeling. MicroPET imaging revealed accumulation of 64Cu-DOTA-etanercept within the lateral and third cerebral ventricles within minutes of peripheral perispinal administration in a normal rat anesthesized with isoflurane anesthesia, with concentration within the choroid plexus and into the CSF. Conclusion Synthesis of 64Cu-DOTA-etanercept enabled visualization of its intracranial distribution by microPET imaging. MicroPET imaging documented rapid accumulation of 64Cu-DOTA-etanercept within the choroid plexus and the cerebrospinal fluid within the cerebral ventricles of a living rat after peripheral administration. Further study of the effects of etanercept and TNF at the level of the choroid plexus may yield valuable insights into the pathogenesis of Alzheimer's disease.

Aerial somersault performance under three visual conditions.

Science.gov (United States)

Hondzinski, J M; Darling, W G

2001-07-01

Experiments were designed to examine the visual contributions to performance of back aerial double somersaults by collegiate acrobats. Somersaults were performed on a trampoline under three visual conditions: (a) NORMAL acuity; (b) REDUCED acuity (subjects wore special contacts that blocked light reflected onto the central retina); and (c) NO VISION. Videotaped skill performances were rated by two NCAA judges and digitized for kinematic analyses. Subjects' performance scores were similar in NORMAL and REDUCED conditions and lowest in the NO VISION condition. Control of body movement, indicated by time-to-contact, was most variable in the NO VISION condition. Profiles of angular head and neck velocity revealed that when subjects could see, they slowed their heads prior to touchdown in time to process optical flow information and prepare for landing. There was not always enough time to process vision associated with object identification and prepare for touchdown. It was concluded that collegiate acrobats do not need to identify objects for their best back aerial double somersault performance.

Vascular access in neonatology: peripherally inserted central catheter and peripheral venous catheter

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Marcia Lienemann

2014-04-01

The objective of this paper is to present aspects of peripherally inserted central catheter and peripheral venous catheter, highlighting important points in choosing the type of access. For the passage of peripherally inserted central catheter is previously performing specific course necessary, while the primary indication occurs when it is necessary to access the patient's stay for a long period of time. Whereas peripheral venipuncture is the most appropriate in cases of needing an IV line quickly and safely, for the administration of fluids, blood collection, blood transfusion and other.

Zilog UPC, a higher performance slave peripheral controller

Energy Technology Data Exchange (ETDEWEB)

Walters, S.M.

1982-01-01

The universal peripheral controllers Z8090 and Z8590 (UPC) is an intelligent peripheral controller. It may be mask-programmed to execute dedicated I/O tasks that would otherwise need to be done by the host microprocessor. The UPC is actually a single-chip microcomputer with a complete host bus interface on-chip. It offers the hardware features of a programmable parallel I/O port, a programmable counter/timer, an I/O buffer RAM, and an intelligent interrupt controller. In addition, it provides a stored program processing element that is capable of pre-processing information before it is transferred to the host. Perhaps as important as its features is the fact that when used in volume, the UPC will be comparable in cost to non-programmable LSI parallel I/O and counter/timer functions. The UPC, simply stated, offers a cost effective multi-processor approach for offloading the host microprocessor of routine peripheral control tasks in high volume applications.

Long-term Outcome of Argon Laser Peripheral Iridoplasty in the Management of Plateau Iris Syndrome Eyes.

Science.gov (United States)

Peterson, Jeffrey R; Anderson, John W; Blieden, Lauren S; Chuang, Alice Z; Feldman, Robert M; Bell, Nicholas P

2017-09-01

To report long-term (>5 y) outcomes of plateau iris syndrome patients treated with argon laser peripheral iridoplasty (ALPI). A retrospective chart review was performed on all patients with plateau iris syndrome treated with ALPI from 1996 to 2007. The study included 22 eyes from 22 patients with plateau iris after peripheral iridotomy that were followed for at least 1 year after ALPI. The primary outcome was incidence of needing any intraocular pressure (IOP)-lowering medications or surgery (either a filtering procedure or phacoemulsification). Demographic and baseline clinical data were summarized by mean (±SD) or frequency (percentage). Snellen best-corrected visual acuity was converted to logMAR. The paired t test was used to compare IOP changes, number of IOP-lowering medications, and best-corrected visual acuity from baseline to annual follow-up. Mean follow-up was 76 months. Only 2 (9%) eyes maintained an IOPiris in our patient population.

Severe hypoxia affects exercise performance independently of afferent feedback and peripheral fatigue.

Science.gov (United States)

Millet, Guillaume Y; Muthalib, Makii; Jubeau, Marc; Laursen, Paul B; Nosaka, Kazunori

2012-04-01

To test the hypothesis that hypoxia centrally affects performance independently of afferent feedback and peripheral fatigue, we conducted two experiments under complete vascular occlusion of the exercising muscle under different systemic O(2) environmental conditions. In experiment 1, 12 subjects performed repeated submaximal isometric contractions of the elbow flexor to exhaustion (RCTE) with inspired O(2) fraction fixed at 9% (severe hypoxia, SevHyp), 14% (moderate hypoxia, ModHyp), 21% (normoxia, Norm), or 30% (hyperoxia, Hyper). The number of contractions (performance), muscle (biceps brachii), and prefrontal near-infrared spectroscopy (NIRS) parameters and high-frequency paired-pulse (PS100) evoked responses to electrical muscle stimulation were monitored. In experiment 2, 10 subjects performed another RCTE in SevHyp and Norm conditions in which the number of contractions, biceps brachii electromyography responses to electrical nerve stimulation (M wave), and transcranial magnetic stimulation responses (motor-evoked potentials, MEP, and cortical silent period, CSP) were recorded. Performance during RCTE was significantly reduced by 10-15% in SevHyp (arterial O(2) saturation, SpO(2) = ∼75%) compared with ModHyp (SpO(2) = ∼90%) or Norm/Hyper (SpO(2) > 97%). Performance reduction in SevHyp occurred despite similar 1) metabolic (muscle NIRS parameters) and functional (changes in PS100 and M wave) muscle states and 2) MEP and CSP responses, suggesting comparable corticospinal excitability and spinal and cortical inhibition between SevHyp and Norm. It is concluded that, in SevHyp, performance and central drive can be altered independently of afferent feedback and peripheral fatigue. It is concluded that submaximal performance in SevHyp is partly reduced by a mechanism related directly to brain oxygenation.

Macular degeneration affects eye movement behaviour during visual search

Directory of Open Access Journals (Sweden)

Stefan eVan Der Stigchel

2013-09-01

Full Text Available Patients with a scotoma in their central vision (e.g. due to macular degeneration, MD commonly adopt a strategy to direct the eyes such that the image falls onto a peripheral location on the retina. This location is referred to as the preferred retinal locus (PRL. Although previous research has investigated the characteristics of this PRL, it is unclear whether eye movement metrics are modulated by peripheral viewing with a PRL as measured during a visual search paradigm. To this end, we tested four MD patients in a visual search paradigm and contrasted their performance with a healthy control group and a healthy control group performing the same experiment with a simulated scotoma. The experiment contained two conditions. In the first condition the target was an unfilled circle hidden among c-shaped distractors (serial condition and in the second condition the target was a filled circle (pop-out condition. Saccadic search latencies for the MD group were significantly longer in both conditions compared to both control groups. Results of a subsequent experiment indicated that this difference between the MD and the control groups could not be explained by a difference in target selection sensitivity. Furthermore, search behaviour of MD patients was associated with saccades with smaller amplitudes towards the scotoma, an increased intersaccadic interval and an increased number of eye movements necessary to locate the target. Some of these characteristics, such as the increased intersaccadic interval, were also observed in the simulation group, which indicate that these characteristics are related to the peripheral viewing itself. We suggest that the combination of the central scotoma and peripheral viewing can explain the altered search behaviour and no behavioural evidence was found for a possible reorganization of the visual system associated with the use of a PRL. Thus the switch from a fovea-based to a PRL-based reference frame impairs search

Visual and flight performance recovery after PRK or LASIK in helicopter pilots.

Science.gov (United States)

Van de Pol, Corina; Greig, Joanna L; Estrada, Art; Bissette, Gina M; Bower, Kraig S

2007-06-01

Refractive surgery, specifically photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), is becoming more accepted in the military environment. Determination of the impact on visual performance in the more demanding aviation environment was the impetus for this study. A prospective evaluation of 20 Black Hawk pilots pre-surgically and at 1 wk, 1 mo, and 6 mo postsurgery was conducted to assess both PRK and LASIK visual and flight performance outcomes on the return of aviators to duty. Of 20 pilots, 19 returned to flight status at 1 mo after surgery; 1 PRK subject was delayed due to corneal haze and subjective visual symptoms. Improvements were seen under simulator night and night vision goggle flight after LASIK; no significant changes in flight performance were measured in the aircraft. Results indicated a significantly faster recovery of all visual performance outcomes 1 wk after LASIK vs. PRK, with no difference between procedures at 1 and 6 mo. Low contrast acuity and contrast sensitivity only weakly correlated to flight performance in the early post-operative period. Overall flight performance assessed in this study after PRK and LASIK was stable or improved from baseline, indicating a resilience of performance despite measured decrements in visual performance, especially in PRK. More visually demanding flight tasks may be impacted by subtle changes in visual performance. Contrast tests are more sensitive to the effects of refractive surgical intervention and may prove to be a better indicator of visual recovery for return to flight status.

Prism therapy and visual rehabilitation in homonymous visual field loss.

LENUS (Irish Health Repository)

O'Neill, Evelyn C

2012-02-01

PURPOSE: Homonymous visual field defects (HVFD) are common and frequently occur after cerebrovascular accidents. They significantly impair visual function and cause disability particularly with regard to visual exploration. The purpose of this study was to assess a novel interventional treatment of monocular prism therapy on visual functioning in patients with HVFD of varied etiology using vision targeted, health-related quality of life (QOL) questionnaires. Our secondary aim was to confirm monocular and binocular visual field expansion pre- and posttreatment. METHODS: Twelve patients with acquired, documented HVFD were eligible to be included. All patients underwent specific vision-targeted, health-related QOL questionnaire and monocular and binocular Goldmann perimetry before commencing prism therapy. Patients were fitted with monocular prisms on the side of the HVFD with the base-in the direction of the field defect creating a peripheral optical exotropia and field expansion. After the treatment period, QOL questionnaires and perimetry were repeated. RESULTS: Twelve patients were included in the treatment group, 10 of whom were included in data analysis. Overall, there was significant improvement within multiple vision-related, QOL functioning parameters, specifically within the domains of general health (p < 0.01), general vision (p < 0.05), distance vision (p < 0.01), peripheral vision (p < 0.05), role difficulties (p < 0.05), dependency (p < 0.05), and social functioning (p < 0.05). Visual field expansion was shown when measured monocularly and binocularly during the study period in comparison with pretreatment baselines. CONCLUSIONS: Patients with HVFD demonstrate decreased QOL. Monocular sector prisms can improve the QOL and expand the visual field in these patients.

Peripheral iridotomy for pigmentary glaucoma

Science.gov (United States)

Michelessi, Manuele; Lindsley, Kristina

2016-01-01

Background Glaucoma is a chronic optic neuropathy characterized by retinal ganglion cell death resulting in damage to the optic nerve head and the retinal nerve fiber layer. Pigment dispersion syndrome is characterized by a structural disturbance in the iris pigment epithelium (the densely pigmented posterior surface of the iris) that leads to dispersion of the pigment and its deposition on various structures within the eye. Pigmentary glaucoma is a specific form of open-angle glaucoma found in patients with pigment dispersion syndrome. Topcial medical therapy is usually the first-line treatment; however, peripheral laser iridotomy has been proposed as an alternate treatment. Peripheral laser iridotomy involves creating an opening in the iris tissue to allow drainage of fluid from the posterior chamber to the anterior chamber and vice versa. Equalizing the pressure within the eye may help to alleviate the friction that leads to pigment dispersion and prevent visual field deterioration. However, the effectiveness of peripheral laser iridotomy in reducing the development or progression of pigmentary glaucoma is unknown. Objectives The objective of this review was to assess the effects of peripheral laser iridotomy compared with other interventions, including medication, trabeculoplasty, and trabeculectomy, or no treatment, for pigment dispersion syndrome and pigmentary glaucoma. Search methods We searched a number of electronic databases including CENTRAL, MEDLINE and EMBASE and clinical trials websites such as (mRCT) and ClinicalTrials.gov. We last searched the electronic databases on 2 November 2015. Selection criteria We included randomized controlled trials (RCTs) that had compared peripheral laser iridotomy versus no treatment or other treatments for pigment dispersion syndrome and pigmentary glaucoma. Data collection and analysis We used standard methodological procedures for systematic reviews. Two review authors independently screened articles for eligibility

Lateralized visual behavior in bottlenose dolphins (Tursiops truncatus) performing audio-visual tasks: the right visual field advantage.

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Delfour, F; Marten, K

2006-01-10

Analyzing cerebral asymmetries in various species helps in understanding brain organization. The left and right sides of the brain (lateralization) are involved in different cognitive and sensory functions. This study focuses on dolphin visual lateralization as expressed by spontaneous eye preference when performing a complex cognitive task; we examine lateralization when processing different visual stimuli displayed on an underwater touch-screen (two-dimensional figures, three-dimensional figures and dolphin/human video sequences). Three female bottlenose dolphins (Tursiops truncatus) were submitted to a 2-, 3- or 4-, choice visual/auditory discrimination problem, without any food reward: the subjects had to correctly match visual and acoustic stimuli together. In order to visualize and to touch the underwater target, the dolphins had to come close to the touch-screen and to position themselves using monocular vision (left or right eye) and/or binocular naso-ventral vision. The results showed an ability to associate simple visual forms and auditory information using an underwater touch-screen. Moreover, the subjects showed a spontaneous tendency to use monocular vision. Contrary to previous findings, our results did not clearly demonstrate right eye preference in spontaneous choice. However, the individuals' scores of correct answers were correlated with right eye vision, demonstrating the advantage of this visual field in visual information processing and suggesting a left hemispheric dominance. We also demonstrated that the nature of the presented visual stimulus does not seem to have any influence on the animals' monocular vision choice.

Action video game players and deaf observers have larger Goldmann visual fields.

Science.gov (United States)

Buckley, David; Codina, Charlotte; Bhardwaj, Palvi; Pascalis, Olivier

2010-03-05

We used Goldmann kinetic perimetry to compare how training and congenital auditory deprivation may affect the size of the visual field. We measured the ability of action video game players and deaf observers to detect small moving lights at various locations in the central (around 30 degrees from fixation) and peripheral (around 60 degrees ) visual fields. Experiment 1 found that 10 habitual video game players showed significantly larger central and peripheral field areas than 10 controls. In Experiment 2 we found that 13 congenitally deaf observers had significantly larger visual fields than 13 hearing controls for both the peripheral and central fields. Here the greatest differences were found in the lower parts of the fields. Comparison of the two groups showed that whereas VGP players have a more uniform increase in field size in both central and peripheral fields deaf observers show non-uniform increases with greatest increases in lower parts of the visual field.

Visual Working Memory Enhances the Neural Response to Matching Visual Input.

Science.gov (United States)

Gayet, Surya; Guggenmos, Matthias; Christophel, Thomas B; Haynes, John-Dylan; Paffen, Chris L E; Van der Stigchel, Stefan; Sterzer, Philipp

2017-07-12

Visual working memory (VWM) is used to maintain visual information available for subsequent goal-directed behavior. The content of VWM has been shown to affect the behavioral response to concurrent visual input, suggesting that visual representations originating from VWM and from sensory input draw upon a shared neural substrate (i.e., a sensory recruitment stance on VWM storage). Here, we hypothesized that visual information maintained in VWM would enhance the neural response to concurrent visual input that matches the content of VWM. To test this hypothesis, we measured fMRI BOLD responses to task-irrelevant stimuli acquired from 15 human participants (three males) performing a concurrent delayed match-to-sample task. In this task, observers were sequentially presented with two shape stimuli and a retro-cue indicating which of the two shapes should be memorized for subsequent recognition. During the retention interval, a task-irrelevant shape (the probe) was briefly presented in the peripheral visual field, which could either match or mismatch the shape category of the memorized stimulus. We show that this probe stimulus elicited a stronger BOLD response, and allowed for increased shape-classification performance, when it matched rather than mismatched the concurrently memorized content, despite identical visual stimulation. Our results demonstrate that VWM enhances the neural response to concurrent visual input in a content-specific way. This finding is consistent with the view that neural populations involved in sensory processing are recruited for VWM storage, and it provides a common explanation for a plethora of behavioral studies in which VWM-matching visual input elicits a stronger behavioral and perceptual response. SIGNIFICANCE STATEMENT Humans heavily rely on visual information to interact with their environment and frequently must memorize such information for later use. Visual working memory allows for maintaining such visual information in the mind

High performance visual display for HENP detectors

CERN Document Server

McGuigan, M; Spiletic, J; Fine, V; Nevski, P

2001-01-01

A high end visual display for High Energy Nuclear Physics (HENP) detectors is necessary because of the sheer size and complexity of the detector. For BNL this display will be of special interest because of STAR and ATLAS. To load, rotate, query, and debug simulation code with a modern detector simply takes too long even on a powerful work station. To visualize the HENP detectors with maximal performance we have developed software with the following characteristics. We develop a visual display of HENP detectors on BNL multiprocessor visualization server at multiple level of detail. We work with general and generic detector framework consistent with ROOT, GAUDI etc, to avoid conflicting with the many graphic development groups associated with specific detectors like STAR and ATLAS. We develop advanced OpenGL features such as transparency and polarized stereoscopy. We enable collaborative viewing of detector and events by directly running the analysis in BNL stereoscopic theatre. We construct enhanced interactiv...

[Ultrasound-guided peripheral catheterization].

Science.gov (United States)

Salleras-Duran, Laia; Fuentes-Pumarola, Concepció

2016-01-01

Peripheral catheterization is a technique that can be difficult in some patients. Some studies have recently described the use of ultrasound to guide the venous catheterization. To describe the success rate, time required, complications of ultrasound-guided peripheral venous catheterization. and patients and professionals satisfaction The search was performed in databases (Medline-PubMed, Cochrane Library, CINAHL and Cuiden Plus) for studies published about ultrasound-guided peripheral venous catheterization performed on patients that provided results on the success of the technique, complications, time used, patient satisfaction and the type of professional who performed the technique. A total of 21 studies were included. Most of them get a higher success rate 80% in the catheterization ecoguide and time it is not higher than the traditional technique. The Technical complications analyzed were arterial puncture rates and lower nerve 10%. In all studies measuring and comparing patient satisfaction in the art ecoguide is greater. Various professional groups perform the technique. The use of ultrasound for peripheral pipes has a high success rate, complications are rare and the time used is similar to that of the traditional technique. The technique of inserting catheters through ultrasound may be learned by any professional group performing venipuncture. Finally, it gets underscores the high patient satisfaction with the use of this technique. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

High Performance Molecular Visualization: In-Situ and Parallel Rendering with EGL

Science.gov (United States)

Stone, John E.; Messmer, Peter; Sisneros, Robert; Schulten, Klaus

2016-01-01

Large scale molecular dynamics simulations produce terabytes of data that is impractical to transfer to remote facilities. It is therefore necessary to perform visualization tasks in-situ as the data are generated, or by running interactive remote visualization sessions and batch analyses co-located with direct access to high performance storage systems. A significant challenge for deploying visualization software within clouds, clusters, and supercomputers involves the operating system software required to initialize and manage graphics acceleration hardware. Recently, it has become possible for applications to use the Embedded-system Graphics Library (EGL) to eliminate the requirement for windowing system software on compute nodes, thereby eliminating a significant obstacle to broader use of high performance visualization applications. We outline the potential benefits of this approach in the context of visualization applications used in the cloud, on commodity clusters, and supercomputers. We discuss the implementation of EGL support in VMD, a widely used molecular visualization application, and we outline benefits of the approach for molecular visualization tasks on petascale computers, clouds, and remote visualization servers. We then provide a brief evaluation of the use of EGL in VMD, with tests using developmental graphics drivers on conventional workstations and on Amazon EC2 G2 GPU-accelerated cloud instance types. We expect that the techniques described here will be of broad benefit to many other visualization applications. PMID:27747137

Peripheral blood volume influenced by various external factors

Energy Technology Data Exchange (ETDEWEB)

Ittner, A; Scheibe, J; Stoll, W [Friedrich-Schiller-Universitaet, Jena (German Democratic Republic). Bereich Medizin

1982-01-01

The dependence of the peripheral blood volume upon various exogenous factors was studied in male sports students using /sup 113m/InCl. The results obtained revealed that whole-body exertions and local muscular activity produce an increase of the blood volume in the lower extremities associated with increased blood circulation. The passive measures applied caused also an increase of the blood volume, but not in all of the subjects examined. Isometric concentrations led to a highly significant reduction of the peripheral blood volume. The scintigraphic method for the visualization of the blood volume in peripheral regions of the body can be regarded as suitable for the study of hemodynamics and for the substantiation of the efficiency of measures promoting restoration.

Normal and sonographic anatomy of selected peripheral nerves. Part III: Peripheral nerves of the lower limb.

Science.gov (United States)

Kowalska, Berta; Sudoł-Szopińska, Iwona

2012-06-01

The ultrasonographic examination is currently increasingly used in imaging peripheral nerves, serving to supplement the physical examination, electromyography and magnetic resonance imaging. As in the case of other USG imaging studies, the examination of peripheral nerves is non-invasive and well-tolerated by patients. The typical ultrasonographic picture of peripheral nerves as well as the examination technique have been discussed in part I of this article series, following the example of the median nerve. Part II of the series presented the normal anatomy and the technique for examining the peripheral nerves of the upper limb. This part of the article series focuses on the anatomy and technique for examining twelve normal peripheral nerves of the lower extremity: the iliohypogastric and ilioinguinal nerves, the lateral cutaneous nerve of the thigh, the pudendal, sciatic, tibial, sural, medial plantar, lateral plantar, common peroneal, deep peroneal and superficial peroneal nerves. It includes diagrams showing the proper positioning of the sonographic probe, plus USG images of the successively discussed nerves and their surrounding structures. The ultrasonographic appearance of the peripheral nerves in the lower limb is identical to the nerves in the upper limb. However, when imaging the lower extremity, convex probes are more often utilized, to capture deeply-seated nerves. The examination technique, similarly to that used in visualizing the nerves of upper extremity, consists of locating the nerve at a characteristic anatomic reference point and tracking it using the "elevator technique". All 3 parts of the article series should serve as an introduction to a discussion of peripheral nerve pathologies, which will be presented in subsequent issues of the "Journal of Ultrasonography".

Angle observation of laser peripheral iridoplasty for the treatment of acute angle-closure glaucoma which could not be controlled by drugs

Directory of Open Access Journals (Sweden)

Wei Han

2013-07-01

Full Text Available AIM: To evaluate the effect of laser peripheral iridoplasty(LPIPto treat acute angle-closure glaucoma(AACGwhich could not controlled by drugs and with persistent ocular hypertension. METHODS: Totally 67 patients(69 eyeswith AACG were performed LPIP when intraocular pressure(IOPwas still over 30mmHg after the medicine therapy for 3-6 hours. Visual acuity and intraocular pressure were under detection before laser treatment and 30 minutes, 60 minutes and 2 hours after laser treatment. We measured the anterior chamber depth, width of angle, iris thickness with ultrasound biomicroscope(UBM. Dynamic gonioscopy was used to evaluate the degree of peripheral anterior synechia(PAS.RESULTS: Angle open distance(AODafter iridoplasty was increased(PPF=151.79, PCONCLUSION: LPIP can deepen peripheral anterior chamber, increase the angle access and lower the IOP immediately. It is an important ongoing adjuvant treatment, which can reduce the patients suffering by lowering the IOP quickly, reduce the damage of visual function caused by long-term high intraocular pressure, avoid side effect of the drugs, and can improve the prognosis.

Performance-based Physical Functioning and Peripheral Neuropathy in a Population-based Cohort of Women at Midlife

Science.gov (United States)

Ylitalo, Kelly R.; Herman, William H.; Harlow, Siobán D.

2013-01-01

Peripheral neuropathy is underappreciated as a potential cause of functional limitations. In the present article, we assessed the cross-sectional association between peripheral neuropathy and physical functioning and how the longitudinal association between age and functioning differed by neuropathy status. Physical functioning was measured in 1996–2008 using timed performances on stair-climb, walking, sit-to-stand, and balance tests at the Michigan site of the Study of Women's Health Across the Nation, a population-based cohort study of women at midlife (n = 396). Peripheral neuropathy was measured in 2008 and defined as having an abnormal monofilament test result or 4 or more symptoms. We used linear mixed models to determine whether trajectories of physical functioning differed by prevalent neuropathy status. Overall, 27.8% of the women had neuropathy. Stair-climb time differed by neuropathy status (P = 0.04), and for every 1-year increase in age, women with neuropathy had a 1.82% (95% confidence interval: 1.42, 2.21) increase compared with a 0.95% (95% confidence interval: 0.71, 1.20) increase for women without neuropathy. Sit-to-stand time differed by neuropathy status (P = 0.01), but the rate of change did not differ. No differences between neuropathy groups were observed for the walk test. For some performance-based tasks, poor functioning was maintained or exacerbated for women who had prevalent neuropathy. Peripheral neuropathy may play a role in physical functioning limitations and future disability. PMID:23524038

Shape representation modulating the effect of motion on visual search performance.

Science.gov (United States)

Yang, Lindong; Yu, Ruifeng; Lin, Xuelian; Liu, Na

2017-11-02

The effect of motion on visual search has been extensively investigated, but that of uniform linear motion of display on search performance for tasks with different target-distractor shape representations has been rarely explored. The present study conducted three visual search experiments. In Experiments 1 and 2, participants finished two search tasks that differed in target-distractor shape representations under static and dynamic conditions. Two tasks with clear and blurred stimuli were performed in Experiment 3. The experiments revealed that target-distractor shape representation modulated the effect of motion on visual search performance. For tasks with low target-distractor shape similarity, motion negatively affected search performance, which was consistent with previous studies. However, for tasks with high target-distractor shape similarity, if the target differed from distractors in that a gap with a linear contour was added to the target, and the corresponding part of distractors had a curved contour, motion positively influenced search performance. Motion blur contributed to the performance enhancement under dynamic conditions. The findings are useful for understanding the influence of target-distractor shape representation on dynamic visual search performance when display had uniform linear motion.

Role of syllable segmentation processes in peripheral word recognition.

Science.gov (United States)

Bernard, Jean-Baptiste; Calabrèse, Aurélie; Castet, Eric

2014-12-01

Previous studies of foveal visual word recognition provide evidence for a low-level syllable decomposition mechanism occurring during the recognition of a word. We investigated if such a decomposition mechanism also exists in peripheral word recognition. Single words were visually presented to subjects in the peripheral field using a 6° square gaze-contingent simulated central scotoma. In the first experiment, words were either unicolor or had their adjacent syllables segmented with two different colors (color/syllable congruent condition). Reaction times for correct word identification were measured for the two different conditions and for two different print sizes. Results show a significant decrease in reaction time for the color/syllable congruent condition compared with the unicolor condition. A second experiment suggests that this effect is specific to syllable decomposition and results from strategic, presumably involving attentional factors, rather than stimulus-driven control.

Visual field tunneling in aviators induced by memory demands.

Science.gov (United States)

Williams, L J

1995-04-01

Aviators are required rapidly and accurately to process enormous amounts of visual information located foveally and peripherally. The present study, expanding upon an earlier study (Williams, 1988), required young aviators to process within the framework of a single eye fixation a briefly displayed foveally presented memory load while simultaneously trying to identify common peripheral targets presented on the same display at locations up to 4.5 degrees of visual angle from the fixation point. This task, as well as a character classification task (Williams, 1985, 1988), has been shown to be very difficult for nonaviators: It results in a tendency toward tunnel vision. Limited preliminary measurements of peripheral accuracy suggested that aviators might be less susceptible than nonaviators to this visual tunneling. The present study demonstrated moderate susceptibility to cognitively induced tunneling in aviators when the foveal task was sufficiently difficult and reaction time was the principal dependent measure.

Peripheral doses of cranial pediatric IMRT performed with attenuator blocks

International Nuclear Information System (INIS)

Soboll, Danyel Scheidegger; Schitz, Ivette; Schelin, Hugo Reuters; Silva, Ricardo Goulart da; Viamonte, Alfredo

2011-01-01

This paper presents values of peripheral doses measured at six vital points of simulator objects which represent the ages of 2, 5 and 10 years old, submitted to a cranial IMRT procedure that applied compensator blocks interposed to 6 MV beams. The found values indicate that there is independence of dose with position of measurements and age of the patient, as the peripheral dose at the points nearest and the 2 year old simulator object where larger. The doses in thyroid reached the range of 1.4 to 2.9% of the dose prescribed in the isocenter, indicating that the peripheral doses for IMRT that employ compensator blocks can be greater than for the IMRT produced with sliding window technique

Alpha-Band Rhythms in Visual Task Performance: Phase-Locking by Rhythmic Sensory Stimulation

Science.gov (United States)

de Graaf, Tom A.; Gross, Joachim; Paterson, Gavin; Rusch, Tessa; Sack, Alexander T.; Thut, Gregor

2013-01-01

Oscillations are an important aspect of neuronal activity. Interestingly, oscillatory patterns are also observed in behaviour, such as in visual performance measures after the presentation of a brief sensory event in the visual or another modality. These oscillations in visual performance cycle at the typical frequencies of brain rhythms, suggesting that perception may be closely linked to brain oscillations. We here investigated this link for a prominent rhythm of the visual system (the alpha-rhythm, 8–12 Hz) by applying rhythmic visual stimulation at alpha-frequency (10.6 Hz), known to lead to a resonance response in visual areas, and testing its effects on subsequent visual target discrimination. Our data show that rhythmic visual stimulation at 10.6 Hz: 1) has specific behavioral consequences, relative to stimulation at control frequencies (3.9 Hz, 7.1 Hz, 14.2 Hz), and 2) leads to alpha-band oscillations in visual performance measures, that 3) correlate in precise frequency across individuals with resting alpha-rhythms recorded over parieto-occipital areas. The most parsimonious explanation for these three findings is entrainment (phase-locking) of ongoing perceptually relevant alpha-band brain oscillations by rhythmic sensory events. These findings are in line with occipital alpha-oscillations underlying periodicity in visual performance, and suggest that rhythmic stimulation at frequencies of intrinsic brain-rhythms can be used to reveal influences of these rhythms on task performance to study their functional roles. PMID:23555873

Effect of prematurity and low birth weight in visual abilities and school performance.

Science.gov (United States)

Perez-Roche, T; Altemir, I; Giménez, G; Prieto, E; González, I; Peña-Segura, J L; Castillo, O; Pueyo, V

2016-12-01

Prematurity and low birth weight are known risk factors for cognitive and developmental impairments, and school failure. Visual perceptual and visual motor skills seem to be among the most affected cognitive domains in these children. To assess the influence of prematurity and low birth weight in visual cognitive skills and school performance. We performed a prospective cohort study, which included 80 boys and girls in an age range from 5 to 13. Subjects were grouped by gestational age at birth (preterm, birth weight (small for gestational age (SGA), school performance in children. Figure-ground skill and visual motor integration were significantly decreased in the preterm birth group, compared with term control subjects (figure-ground: 45.7 vs 66.5, p=0.012; visual motor integration, TVAS: (9.9 vs 11.8, p=0.018), while outcomes of visual memory (29.0 vs 47.7, p=0.012), form constancy (33.3 vs 52.8, p=0.019), figure-ground (37.4 vs 65.6, p=0.001), and visual closure (43.7 vs 62.6 p=0.016) testing were lower in the SGA (vs AGA) group. Visual cognitive difficulties corresponded with worse performance in mathematics (r=0.414, p=0.004) and reading (r=0.343, p=0.018). Specific patterns of visual perceptual and visual motor deficits are displayed by children born preterm or SGA, which hinder mathematics and reading performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Normal and sonographic anatomy of selected peripheral nerves. Part III: Peripheral nerves of the lower limb

Directory of Open Access Journals (Sweden)

Berta Kowalska

2012-06-01

Full Text Available The ultrasonographic examination is currently increasingly used in imaging peripheral nerves, serving to supplement the physical examination, electromyography and magnetic resonance imaging. As in the case of other USG imaging studies, the examination of peripheral nerves is non-invasive and well-tolerated by patients. The typical ultrasonographic picture of peripheral nerves as well as the examination technique have been discussed in part I of this article series, following the example of the median nerve. Part II of the series presented the normal anatomy and the technique for examining the peripheral nerves of the upper limb. This part of the article series focuses on the anatomy and technique for examining twelve normal peripheral nerves of the lower extremity: the iliohypogastric and ilioinguinal nerves, the lateral cutaneous nerve of the thigh, the pudendal, sciatic, tibial, sural, medial plantar, lateral plantar, common peroneal, deep peroneal and superficial peroneal nerves. It includes diagrams showing the proper positioning of the sonographic probe, plus USG images of the successively discussed nerves and their surrounding structures. The ultrasonographic appearance of the peripheral nerves in the lower limb is identical to the nerves in the upper limb. However, when imaging the lower extremity, convex probes are more often utilized, to capture deeply-seated nerves. The examination technique, similarly to that used in visualizing the nerves of upper extremity, consists of locating the nerve at a characteristic anatomic reference point and tracking it using the “elevator technique”. All 3 parts of the article series should serve as an introduction to a discussion of peripheral nerve pathologies, which will be presented in subsequent issues of the “Journal of Ultrasonography”.

High performance visual display for HENP detectors

International Nuclear Information System (INIS)

McGuigan, Michael; Smith, Gordon; Spiletic, John; Fine, Valeri; Nevski, Pavel

2001-01-01

A high end visual display for High Energy Nuclear Physics (HENP) detectors is necessary because of the sheer size and complexity of the detector. For BNL this display will be of special interest because of STAR and ATLAS. To load, rotate, query, and debug simulation code with a modern detector simply takes too long even on a powerful work station. To visualize the HENP detectors with maximal performance we have developed software with the following characteristics. We develop a visual display of HENP detectors on BNL multiprocessor visualization server at multiple level of detail. We work with general and generic detector framework consistent with ROOT, GAUDI etc, to avoid conflicting with the many graphic development groups associated with specific detectors like STAR and ATLAS. We develop advanced OpenGL features such as transparency and polarized stereoscopy. We enable collaborative viewing of detector and events by directly running the analysis in BNL stereoscopic theatre. We construct enhanced interactive control, including the ability to slice, search and mark areas of the detector. We incorporate the ability to make a high quality still image of a view of the detector and the ability to generate animations and a fly through of the detector and output these to MPEG or VRML models. We develop data compression hardware and software so that remote interactive visualization will be possible among dispersed collaborators. We obtain real time visual display for events accumulated during simulations

Using optic flow in the far peripheral field.

Science.gov (United States)

McManus, Meaghan; D'Amour, Sarah; Harris, Laurence R

2017-07-01

Self-motion information can be used to update spatial memory of location through an estimate of a change in position. Viewing optic flow alone can create Illusory self-motion or "vection." Early studies suggested that peripheral vision is more effective than central vision in evoking vection, but controlling for retinal area and perceived distance suggests that all retinal areas may be equally effective. However, the contributions of the far periphery, beyond 90°, have been largely neglected. Using a large-field Edgeless Graphics Geometry display (EGG, Christie, Canada, field of view ±112°) and systematically blocking central (±20° to ±90°) or peripheral (viewing through tunnels ±20° to ±40°) parts of the field, we compared the effectiveness of different retinal regions at evoking forwards linear vection. Fifteen participants indicated when they had reached the position of a previously presented target after visually simulating motion down a simulated corridor. The amount of simulated travel needed to match a given target distance was modelled with a leaky spatial integrator model to estimate gains (perceived/actual distance) and a spatial decay factor. When optic flow was presented only in the far periphery (beyond 90°) gains were significantly higher than for the same motion presented full field or in only the central field, resulting in accurate performance in the range of speeds associated with normal walking. The increased effectiveness of optic flow in the peripheral field alone compared to full-field motion is discussed in terms of emerging neurophysiological studies that suggest brain areas dedicated to processing information from the far peripheral field.

The peripheral blood volume influenced by various external factors

International Nuclear Information System (INIS)

Ittner, A.; Scheibe, J.; Stoll, W.

1982-01-01

The dependence of the peripheral blood volume upon various exogenous factors was studied in male sports students using /sup 113m/InCl. The results obtained revealed that whole-body exertions and local muscular activity produce an increase of the blood volume in the lower extremities associated with increased blood circulation. The passive measures applied caused also an increase of the blood volume, but not in all of the subjects examined. Isometric concentrations led to a highly significant reduction of the peripheral blood volume. The scintigraphic method for the visualization of the blood volume in peripheral regions of the body can be regarded as suitable for the study of hemodynamics and for the substantiation of the efficiency of measures promoting restoration. (author)

PERIPHERAL RETINAL FINDINGS IN HIGHLY MYOPIC CHILDREN ≤10 YEARS OF AGE

Science.gov (United States)

Bansal, Alok S.; Hubbard, G. Baker

2011-01-01

Purpose The purpose of this study was to characterize the peripheral retinal findings in highly myopic young children without other known risk factors for retinal detachment. Methods A retrospective review of all cases of children ≤10 years of age with high myopia (>6.00 diopters) who were evaluated for presumed risk of retinal detachment by either an examination under anesthesia or office examination by a single retina specialist from January 2001 through December 2008. Patients with regressed retinopathy of pre-maturity, retinal detachment in the fellow eye, or known Stickler syndrome were excluded. Results Fifty-four eyes of 30 patients with high myopia were examined. Twenty-six eyes of 14 patients were examined under anesthesia because of the examiner’s inability to adequately visualize the peripheral retina during an office examination. Mean age at examination was 6 ± 3 (range, 1–10) years. Mean spherical equivalent refractive error was −13.88 ± 3.79 (range, −6.00 to −25.00) diopters. Peripheral retinal findings were identified in 33% of eyes, the most common being lattice degeneration (20%), white without pressure (11%), and retinal holes with subretinal fluid (4%). Conclusion Approximately one third of highly myopic children in our study showed peripheral retinal findings. If the peripheral retina is not adequately visualized during an office evaluation, examination under anesthesia should be considered. PMID:20224463

Octopus vulgaris uses visual information to determine the location of its arm.

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Gutnick, Tamar; Byrne, Ruth A; Hochner, Binyamin; Kuba, Michael

2011-03-22

Octopuses are intelligent, soft-bodied animals with keen senses that perform reliably in a variety of visual and tactile learning tasks. However, researchers have found them disappointing in that they consistently fail in operant tasks that require them to combine central nervous system reward information with visual and peripheral knowledge of the location of their arms. Wells claimed that in order to filter and integrate an abundance of multisensory inputs that might inform the animal of the position of a single arm, octopuses would need an exceptional computing mechanism, and "There is no evidence that such a system exists in Octopus, or in any other soft bodied animal." Recent electrophysiological experiments, which found no clear somatotopic organization in the higher motor centers, support this claim. We developed a three-choice maze that required an octopus to use a single arm to reach a visually marked goal compartment. Using this operant task, we show for the first time that Octopus vulgaris is capable of guiding a single arm in a complex movement to a location. Thus, we claim that octopuses can combine peripheral arm location information with visual input to control goal-directed complex movements. Copyright © 2011 Elsevier Ltd. All rights reserved.

Age-related changes in visual exploratory behavior in a natural scene setting.

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Hamel, Johanna; De Beukelaer, Sophie; Kraft, Antje; Ohl, Sven; Audebert, Heinrich J; Brandt, Stephan A

2013-01-01

Diverse cognitive functions decline with increasing age, including the ability to process central and peripheral visual information in a laboratory testing situation (useful visual field of view). To investigate whether and how this influences activities of daily life, we studied age-related changes in visual exploratory behavior in a natural scene setting: a driving simulator paradigm of variable complexity was tested in subjects of varying ages with simultaneous eye- and head-movement recordings via a head-mounted camera. Detection and reaction times were also measured by visual fixation and manual reaction. We considered video computer game experience as a possible influence on performance. Data of 73 participants of varying ages were analyzed, driving two different courses. We analyzed the influence of route difficulty level, age, and eccentricity of test stimuli on oculomotor and driving behavior parameters. No significant age effects were found regarding saccadic parameters. In the older subjects head-movements increasingly contributed to gaze amplitude. More demanding courses and more peripheral stimuli locations induced longer reaction times in all age groups. Deterioration of the functionally useful visual field of view with increasing age was not suggested in our study group. However, video game-experienced subjects revealed larger saccade amplitudes and a broader distribution of fixations on the screen. They reacted faster to peripheral objects suggesting the notion of a general detection task rather than perceiving driving as a central task. As the video game-experienced population consisted of younger subjects, our study indicates that effects due to video game experience can easily be misinterpreted as age effects if not accounted for. We therefore view it as essential to consider video game experience in all testing methods using virtual media.

Age-related changes in visual exploratory behavior in a natural scene setting

Directory of Open Access Journals (Sweden)

Johanna eHamel

2013-06-01

Full Text Available Diverse cognitive functions decline with increasing age, including the ability to process central and peripheral visual information in a laboratory testing situation (useful visual field of view. To investigate whether and how this influences activities of daily life, we studied age-related changes in visual exploratory behavior in a natural scene setting: a driving simulator paradigm of variable complexity was tested in subjects of varying ages with simultaneous eye- and head-movement recordings via a head-mounted camera. Detection and reaction times were also measured by visual fixation and manual reaction. We considered video computer game experience as a possible influence on performance. Data of 73 participants of varying ages were analyzed, driving two different courses. We analyzed the influence of route difficulty level, age and eccentricity of test stimuli on oculomotor and driving behavior parameters. No significant age effects were found regarding saccadic parameters. In the older subjects head-movements increasingly contributed to gaze amplitude. More demanding courses and more peripheral stimuli locations, induced longer reaction times in all age groups. Deterioration of the functionally useful visual field of view with increasing age was not suggested in our study group. However, video game-experienced subjects revealed larger saccade amplitudes and a broader distribution of fixations on the screen. They reacted faster to peripheral objects suggesting the notion of a general detection task rather than perceiving driving as a central task. As the video game experienced population consisted of younger subjects, our study indicates that effects due to video game experience can easily be misinterpreted as age effects if not accounted for. We therefore view it as essential to consider video game experience in all testing methods using virtual media.

Semantic congruency but not temporal synchrony enhances long-term memory performance for audio-visual scenes.

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Meyerhoff, Hauke S; Huff, Markus

2016-04-01

Human long-term memory for visual objects and scenes is tremendous. Here, we test how auditory information contributes to long-term memory performance for realistic scenes. In a total of six experiments, we manipulated the presentation modality (auditory, visual, audio-visual) as well as semantic congruency and temporal synchrony between auditory and visual information of brief filmic clips. Our results show that audio-visual clips generally elicit more accurate memory performance than unimodal clips. This advantage even increases with congruent visual and auditory information. However, violations of audio-visual synchrony hardly have any influence on memory performance. Memory performance remained intact even with a sequential presentation of auditory and visual information, but finally declined when the matching tracks of one scene were presented separately with intervening tracks during learning. With respect to memory performance, our results therefore show that audio-visual integration is sensitive to semantic congruency but remarkably robust against asymmetries between different modalities.

Functionality and Performance Visualization of the Distributed High Quality Volume Renderer (HVR)

KAUST Repository

Shaheen, Sara

2012-07-01

Volume rendering systems are designed to provide means to enable scientists and a variety of experts to interactively explore volume data through 3D views of the volume. However, volume rendering techniques are computationally intensive tasks. Moreover, parallel distributed volume rendering systems and multi-threading architectures were suggested as natural solutions to provide an acceptable volume rendering performance for very large volume data sizes, such as Electron Microscopy data (EM). This in turn adds another level of complexity when developing and manipulating volume rendering systems. Given that distributed parallel volume rendering systems are among the most complex systems to develop, trace and debug, it is obvious that traditional debugging tools do not provide enough support. As a consequence, there is a great demand to provide tools that are able to facilitate the manipulation of such systems. This can be achieved by utilizing the power of compute graphics in designing visual representations that reflect how the system works and that visualize the current performance state of the system.The work presented is categorized within the field of software Visualization, where Visualization is used to serve visualizing and understanding various software. In this thesis, a number of visual representations that reflect a number of functionality and performance aspects of the distributed HVR, a high quality volume renderer system that uses various techniques to visualize large volume sizes interactively. This work is provided to visualize different stages of the parallel volume rendering pipeline of HVR. This is along with means of performance analysis through a number of flexible and dynamic visualizations that reflect the current state of the system and enables manipulation of them at runtime. Those visualization are aimed to facilitate debugging, understanding and analyzing the distributed HVR.

PET-scan shows peripherally increased neurokinin 1 receptor availability in chronic tennis elbow: visualizing neurogenic inflammation?

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Magnus Peterson

Full Text Available In response to pain, neurokinin 1 (NK1 receptor availability is altered in the central nervous system. The NK1 receptor and its primary agonist, substance P, also play a crucial role in peripheral tissue in response to pain, as part of neurogenic inflammation. However, little is known about alterations in NK1 receptor availability in peripheral tissue in chronic pain conditions and very few studies have been performed on human beings. Ten subjects with chronic tennis elbow were therefore examined by positron emission tomography (PET with the NK1 specific radioligand [(11C]GR205171 before and after treatment with graded exercise. The radioligand signal intensity was higher in the affected arm as compared with the unaffected arm, measured as differences between the arms in volume of voxels and signal intensity of this volume above a reference threshold set as 2.5 SD above mean signal intensity of the unaffected arm before treatment. In the eight subjects examined after treatment, pain ratings decreased in all subjects but signal intensity decreased in five and increased in three. In conclusion, NK1 receptors may be activated, or up-regulated in the peripheral, painful tissue of a chronic pain condition. This up-regulation does, however, have moderate correlation to pain ratings. The increased NK1 receptor availability is interpreted as part of ongoing neurogenic inflammation and may have correlation to the pathogenesis of chronic tennis elbow.ClinicalTrials.gov NCT00888225 http://clinicaltrials.gov/

Conditions Affecting the Performance of Peripheral Vein Cannulation during Hospital Placement: A Case Study

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Monika Ravik

2017-01-01

Full Text Available Learning practical nursing skills is an important part of the baccalaureate in nursing. However, many newly qualified nurses lack practical skill proficiency required to ensure safe patient care. The invasive skill peripheral vein cannulation (PVC is particularly challenging to learn and perform. This study explored conditions influencing nursing students’ learning and performance of the technical implementation of a PVC during their clinical placement period. A qualitative and descriptive case study design with two students in Norway practicing PVC during their clinical placement was conducted. One student who mastered the vein cannulation was compared with one student who did not. Data were collected in late 2012 using multiple data sources: semistructured interviews, ad hoc conversations, and video recordings. Video recordings of the two students’ cannula implementations were used to help clarify and validate the descriptions and to identify gaps between what students said and what they did. Thematic analysis of the transcribed text data enabled identifying themes that influenced skill performance. There were two overall themes: individual and contextual conditions influencing the technical implementation of a peripheral vein cannula. These findings were evaluated in terms of Benner’s work on scientific and practical knowledge, defined as “knowing that” and “knowing how.”

How visual search relates to visual diagnostic performance: a narrative systematic review of eye-tracking research in radiology.

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van der Gijp, A; Ravesloot, C J; Jarodzka, H; van der Schaaf, M F; van der Schaaf, I C; van Schaik, J P J; Ten Cate, Th J

2017-08-01

Eye tracking research has been conducted for decades to gain understanding of visual diagnosis such as in radiology. For educational purposes, it is important to identify visual search patterns that are related to high perceptual performance and to identify effective teaching strategies. This review of eye-tracking literature in the radiology domain aims to identify visual search patterns associated with high perceptual performance. Databases PubMed, EMBASE, ERIC, PsycINFO, Scopus and Web of Science were searched using 'visual perception' OR 'eye tracking' AND 'radiology' and synonyms. Two authors independently screened search results and included eye tracking studies concerning visual skills in radiology published between January 1, 1994 and July 31, 2015. Two authors independently assessed study quality with the Medical Education Research Study Quality Instrument, and extracted study data with respect to design, participant and task characteristics, and variables. A thematic analysis was conducted to extract and arrange study results, and a textual narrative synthesis was applied for data integration and interpretation. The search resulted in 22 relevant full-text articles. Thematic analysis resulted in six themes that informed the relation between visual search and level of expertise: (1) time on task, (2) eye movement characteristics of experts, (3) differences in visual attention, (4) visual search patterns, (5) search patterns in cross sectional stack imaging, and (6) teaching visual search strategies. Expert search was found to be characterized by a global-focal search pattern, which represents an initial global impression, followed by a detailed, focal search-to-find mode. Specific task-related search patterns, like drilling through CT scans and systematic search in chest X-rays, were found to be related to high expert levels. One study investigated teaching of visual search strategies, and did not find a significant effect on perceptual performance. Eye

Direct visualization of antigen-specific T cells: HTLV-1 Tax11-19- specific CD8(+) T cells are activated in peripheral blood and accumulate in cerebrospinal fluid from HAM/TSP patients.

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Greten, T F; Slansky, J E; Kubota, R; Soldan, S S; Jaffee, E M; Leist, T P; Pardoll, D M; Jacobson, S; Schneck, J P

1998-06-23

Human T lymphotropic virus type 1 (HTLV-1) -associated myelopathy/tropic spastic paraparesis is a demyelinating inflammatory neurologic disease associated with HTLV-1 infection. HTLV-1 Tax11-19-specific cytotoxic T cells have been isolated from HLA-A2-positive patients. We have used a peptide-loaded soluble HLA-A2-Ig complex to directly visualize HTLV-1 Tax11-19-specific T cells from peripheral blood and cerebrospinal fluid without in vitro stimulation. Five of six HTLV-1-associated myelopathy/tropic spastic paraparesis patients carried a significant number (up to 13.87%) of CD8(+) lymphocytes specific for the HTLV-1 Tax11-19 peptide in their peripheral blood, which were not found in healthy controls. Simultaneous comparison of peripheral blood and cerebrospinal fluid from one patient revealed 2.5-fold more Tax11-19-specific T cells in the cerebrospinal fluid (23.7% vs. 9.4% in peripheral blood lymphocyte). Tax11-19-specific T cells were seen consistently over a 9-yr time course in one patient as far as 19 yrs after the onset of clinical symptoms. Further analysis of HTLV-1 Tax11-19-specific CD8(+) T lymphocytes in HAM/TSP patients showed different expression patterns of activation markers, intracellular TNF-alpha and gamma-interferon depending on the severity of the disease. Thus, visualization of antigen-specific T cells demonstrates that HTLV-1 Tax11-19-specific CD8(+) T cells are activated, persist during the chronic phase of the disease, and accumulate in cerebrospinal fluid, showing their pivotal role in the pathogenesis of this neurologic disease.

Visual search performance among persons with schizophrenia as a function of target eccentricity.

Science.gov (United States)

Elahipanah, Ava; Christensen, Bruce K; Reingold, Eyal M

2010-03-01

The current study investigated one possible mechanism of impaired visual attention among patients with schizophrenia: a reduced visual span. Visual span is the region of the visual field from which one can extract information during a single eye fixation. This study hypothesized that schizophrenia-related visual search impairment is mediated, in part, by a smaller visual span. To test this hypothesis, 23 patients with schizophrenia and 22 healthy controls completed a visual search task where the target was pseudorandomly presented at different distances from the center of the display. Response times were analyzed as a function of search condition (feature vs. conjunctive), display size, and target eccentricity. Consistent with previous reports, patient search times were more adversely affected as the number of search items increased in the conjunctive search condition. It was important however, that patients' conjunctive search times were also impacted to a greater degree by target eccentricity. Moreover, a significant impairment in patients' visual search performance was only evident when targets were more eccentric and their performance was more similar to healthy controls when the target was located closer to the center of the search display. These results support the hypothesis that a narrower visual span may underlie impaired visual search performance among patients with schizophrenia. Copyright 2010 APA, all rights reserved

Evaluating the Performance of a Visually Guided Hearing Aid Using a Dynamic Auditory-Visual Word Congruence Task.

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Roverud, Elin; Best, Virginia; Mason, Christine R; Streeter, Timothy; Kidd, Gerald

2017-12-15

The "visually guided hearing aid" (VGHA), consisting of a beamforming microphone array steered by eye gaze, is an experimental device being tested for effectiveness in laboratory settings. Previous studies have found that beamforming without visual steering can provide significant benefits (relative to natural binaural listening) for speech identification in spatialized speech or noise maskers when sound sources are fixed in location. The aim of the present study was to evaluate the performance of the VGHA in listening conditions in which target speech could switch locations unpredictably, requiring visual steering of the beamforming. To address this aim, the present study tested an experimental simulation of the VGHA in a newly designed dynamic auditory-visual word congruence task. Ten young normal-hearing (NH) and 11 young hearing-impaired (HI) adults participated. On each trial, three simultaneous spoken words were presented from three source positions (-30, 0, and 30 azimuth). An auditory-visual word congruence task was used in which participants indicated whether there was a match between the word printed on a screen at a location corresponding to the target source and the spoken target word presented acoustically from that location. Performance was compared for a natural binaural condition (stimuli presented using impulse responses measured on KEMAR), a simulated VGHA condition (BEAM), and a hybrid condition that combined lowpass-filtered KEMAR and highpass-filtered BEAM information (BEAMAR). In some blocks, the target remained fixed at one location across trials, and in other blocks, the target could transition in location between one trial and the next with a fixed but low probability. Large individual variability in performance was observed. There were significant benefits for the hybrid BEAMAR condition relative to the KEMAR condition on average for both NH and HI groups when the targets were fixed. Although not apparent in the averaged data, some

Power profiles and short-term visual performance of soft contact lenses.

Science.gov (United States)

Papas, Eric; Dahms, Anne; Carnt, Nicole; Tahhan, Nina; Ehrmann, Klaus

2009-04-01

To investigate the manner in which contemporary soft contact lenses differ in the distribution of optical power within their optic zones and establish if these variations affect the vision of wearers or the prescribing procedure for back vertex power (BVP). By using a Visionix VC 2001 contact lens power analyzer, power profiles were measured across the optic zones of the following contemporary contact lenses ACUVUE 2, ACUVUE ADVANCE, O2OPTIX, NIGHT & DAY and PureVision. Single BVP measures were obtained using a Nikon projection lensometer. Visual performance was assessed in 28 masked subjects who wore each lens type in random order. Measurements taken were high and low contrast visual acuity in normal illumination (250 Cd/m), high contrast acuity in reduced illumination (5 Cd/m), subjective visual quality using a numerical rating scale, and visual satisfaction rating using a Likert scale. Marked differences in the distribution of optical power across the optic zone were evident among the lens types. No significant differences were found for any of the visual performance variables (p > 0.05, analysis of variance with repeated measures and Friedman test). Variations in power profile between contemporary soft lens types exist but do not, in general, result in measurable visual performance differences in the short term, nor do they substantially influence the BVP required for optimal correction.

Visual advantage in deaf adults linked to retinal changes.

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Charlotte Codina

Full Text Available The altered sensory experience of profound early onset deafness provokes sometimes large scale neural reorganisations. In particular, auditory-visual cross-modal plasticity occurs, wherein redundant auditory cortex becomes recruited to vision. However, the effect of human deafness on neural structures involved in visual processing prior to the visual cortex has never been investigated, either in humans or animals. We investigated neural changes at the retina and optic nerve head in profoundly deaf (N = 14 and hearing (N = 15 adults using Optical Coherence Tomography (OCT, an in-vivo light interference method of quantifying retinal micro-structure. We compared retinal changes with behavioural results from the same deaf and hearing adults, measuring sensitivity in the peripheral visual field using Goldmann perimetry. Deaf adults had significantly larger neural rim areas, within the optic nerve head in comparison to hearing controls suggesting greater retinal ganglion cell number. Deaf adults also demonstrated significantly larger visual field areas (indicating greater peripheral sensitivity than controls. Furthermore, neural rim area was significantly correlated with visual field area in both deaf and hearing adults. Deaf adults also showed a significantly different pattern of retinal nerve fibre layer (RNFL distribution compared to controls. Significant correlations between the depth of the RNFL at the inferior-nasal peripapillary retina and the corresponding far temporal and superior temporal visual field areas (sensitivity were found. Our results show that cross-modal plasticity after early onset deafness may not be limited to the sensory cortices, noting specific retinal adaptations in early onset deaf adults which are significantly correlated with peripheral vision sensitivity.

Structural reorganization of the early visual cortex following Braille training in sighted adults.

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Bola, Łukasz; Siuda-Krzywicka, Katarzyna; Paplińska, Małgorzata; Sumera, Ewa; Zimmermann, Maria; Jednoróg, Katarzyna; Marchewka, Artur; Szwed, Marcin

2017-12-12

Training can induce cross-modal plasticity in the human cortex. A well-known example of this phenomenon is the recruitment of visual areas for tactile and auditory processing. It remains unclear to what extent such plasticity is associated with changes in anatomy. Here we enrolled 29 sighted adults into a nine-month tactile Braille-reading training, and used voxel-based morphometry and diffusion tensor imaging to describe the resulting anatomical changes. In addition, we collected resting-state fMRI data to relate these changes to functional connectivity between visual and somatosensory-motor cortices. Following Braille-training, we observed substantial grey and white matter reorganization in the anterior part of early visual cortex (peripheral visual field). Moreover, relative to its posterior, foveal part, the peripheral representation of early visual cortex had stronger functional connections to somatosensory and motor cortices even before the onset of training. Previous studies show that the early visual cortex can be functionally recruited for tactile discrimination, including recognition of Braille characters. Our results demonstrate that reorganization in this region induced by tactile training can also be anatomical. This change most likely reflects a strengthening of existing connectivity between the peripheral visual cortex and somatosensory cortices, which suggests a putative mechanism for cross-modal recruitment of visual areas.

Unconscious analyses of visual scenes based on feature conjunctions.

Science.gov (United States)

Tachibana, Ryosuke; Noguchi, Yasuki

2015-06-01

To efficiently process a cluttered scene, the visual system analyzes statistical properties or regularities of visual elements embedded in the scene. It is controversial, however, whether those scene analyses could also work for stimuli unconsciously perceived. Here we show that our brain performs the unconscious scene analyses not only using a single featural cue (e.g., orientation) but also based on conjunctions of multiple visual features (e.g., combinations of color and orientation information). Subjects foveally viewed a stimulus array (duration: 50 ms) where 4 types of bars (red-horizontal, red-vertical, green-horizontal, and green-vertical) were intermixed. Although a conscious perception of those bars was inhibited by a subsequent mask stimulus, the brain correctly analyzed the information about color, orientation, and color-orientation conjunctions of those invisible bars. The information of those features was then used for the unconscious configuration analysis (statistical processing) of the central bars, which induced a perceptual bias and illusory feature binding in visible stimuli at peripheral locations. While statistical analyses and feature binding are normally 2 key functions of the visual system to construct coherent percepts of visual scenes, our results show that a high-level analysis combining those 2 functions is correctly performed by unconscious computations in the brain. (c) 2015 APA, all rights reserved).

Visual determinants of reduced performance on the Stroop color-word test in normal aging individuals.

Science.gov (United States)

van Boxtel, M P; ten Tusscher, M P; Metsemakers, J F; Willems, B; Jolles, J

2001-10-01

It is unknown to what extent the performance on the Stroop color-word test is affected by reduced visual function in older individuals. We tested the impact of common deficiencies in visual function (reduced distant and close acuity, reduced contrast sensitivity, and color weakness) on Stroop performance among 821 normal individuals aged 53 and older. After adjustment for age, sex, and educational level, low contrast sensitivity was associated with more time needed on card I (word naming), red/green color weakness with slower card 2 performance (color naming), and reduced distant acuity with slower performance on card 3 (interference). Half of the age-related variance in speed performance was shared with visual function. The actual impact of reduced visual function may be underestimated in this study when some of this age-related variance in Stroop performance is mediated by visual function decrements. It is suggested that reduced visual function has differential effects on Stroop performance which need to be accounted for when the Stroop test is used both in research and in clinical settings. Stroop performance measured from older individuals with unknown visual status should be interpreted with caution.

Visual Motor and Perceptual Task Performance in Astigmatic Students

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Erin M. Harvey

2017-01-01

Full Text Available Purpose. To determine if spectacle corrected and uncorrected astigmats show reduced performance on visual motor and perceptual tasks. Methods. Third through 8th grade students were assigned to the low refractive error control group (astigmatism < 1.00 D, myopia < 0.75 D, hyperopia < 2.50 D, and anisometropia < 1.50 D or bilateral astigmatism group (right and left eye ≥ 1.00 D based on cycloplegic refraction. Students completed the Beery-Buktenica Developmental Test of Visual Motor Integration (VMI and Visual Perception (VMIp. Astigmats were randomly assigned to testing with/without correction and control group was tested uncorrected. Analyses compared VMI and VMIp scores for corrected and uncorrected astigmats to the control group. Results. The sample included 333 students (control group 170, astigmats tested with correction 75, and astigmats tested uncorrected 88. Mean VMI score in corrected astigmats did not differ from the control group (p=0.829. Uncorrected astigmats had lower VMI scores than the control group (p=0.038 and corrected astigmats (p=0.007. Mean VMIp scores for uncorrected (p=0.209 and corrected astigmats (p=0.124 did not differ from the control group. Uncorrected astigmats had lower mean scores than the corrected astigmats (p=0.003. Conclusions. Uncorrected astigmatism influences visual motor and perceptual task performance. Previously spectacle treated astigmats do not show developmental deficits on visual motor or perceptual tasks when tested with correction.

Visually Evoked Visual-Auditory Changes Associated with Auditory Performance in Children with Cochlear Implants

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Maojin Liang

2017-10-01

Full Text Available Activation of the auditory cortex by visual stimuli has been reported in deaf children. In cochlear implant (CI patients, a residual, more intense cortical activation in the frontotemporal areas in response to photo stimuli was found to be positively associated with poor auditory performance. Our study aimed to investigate the mechanism by which visual processing in CI users activates the auditory-associated cortex during the period after cochlear implantation as well as its relation to CI outcomes. Twenty prelingually deaf children with CI were recruited. Ten children were good CI performers (GCP and ten were poor (PCP. Ten age- and sex- matched normal-hearing children were recruited as controls, and visual evoked potentials (VEPs were recorded. The characteristics of the right frontotemporal N1 component were analyzed. In the prelingually deaf children, higher N1 amplitude was observed compared to normal controls. While the GCP group showed significant decreases in N1 amplitude, and source analysis showed the most significant decrease in brain activity was observed in the primary visual cortex (PVC, with a downward trend in the primary auditory cortex (PAC activity, but these did not occur in the PCP group. Meanwhile, higher PVC activation (comparing to controls before CI use (0M and a significant decrease in source energy after CI use were found to be related to good CI outcomes. In the GCP group, source energy decreased in the visual-auditory cortex with CI use. However, no significant cerebral hemispheric dominance was found. We supposed that intra- or cross-modal reorganization and higher PVC activation in prelingually deaf children may reflect a stronger potential ability of cortical plasticity. Brain activity evolution appears to be related to CI auditory outcomes.

Visually Evoked Visual-Auditory Changes Associated with Auditory Performance in Children with Cochlear Implants.

Science.gov (United States)

Liang, Maojin; Zhang, Junpeng; Liu, Jiahao; Chen, Yuebo; Cai, Yuexin; Wang, Xianjun; Wang, Junbo; Zhang, Xueyuan; Chen, Suijun; Li, Xianghui; Chen, Ling; Zheng, Yiqing

2017-01-01

Activation of the auditory cortex by visual stimuli has been reported in deaf children. In cochlear implant (CI) patients, a residual, more intense cortical activation in the frontotemporal areas in response to photo stimuli was found to be positively associated with poor auditory performance. Our study aimed to investigate the mechanism by which visual processing in CI users activates the auditory-associated cortex during the period after cochlear implantation as well as its relation to CI outcomes. Twenty prelingually deaf children with CI were recruited. Ten children were good CI performers (GCP) and ten were poor (PCP). Ten age- and sex- matched normal-hearing children were recruited as controls, and visual evoked potentials (VEPs) were recorded. The characteristics of the right frontotemporal N1 component were analyzed. In the prelingually deaf children, higher N1 amplitude was observed compared to normal controls. While the GCP group showed significant decreases in N1 amplitude, and source analysis showed the most significant decrease in brain activity was observed in the primary visual cortex (PVC), with a downward trend in the primary auditory cortex (PAC) activity, but these did not occur in the PCP group. Meanwhile, higher PVC activation (comparing to controls) before CI use (0M) and a significant decrease in source energy after CI use were found to be related to good CI outcomes. In the GCP group, source energy decreased in the visual-auditory cortex with CI use. However, no significant cerebral hemispheric dominance was found. We supposed that intra- or cross-modal reorganization and higher PVC activation in prelingually deaf children may reflect a stronger potential ability of cortical plasticity. Brain activity evolution appears to be related to CI auditory outcomes.

Training improves reading speed in peripheral vision: Is it due to attention?

OpenAIRE

Lee, Hye-Won; Kwon, MiYoung; Legge, Gordon E.; Gefroh, Joshua J.

2010-01-01

Previous research has shown that perceptual training in peripheral vision, using a letter-recognition task, increases reading speed and letter recognition (Chung, Legge, & Cheung, 2004). We tested the hypothesis that enhanced deployment of spatial attention to peripheral vision explains this training effect. Subjects were pre- and post-tested with 3 tasks at 10° above and below fixation—RSVP reading speed, trigram letter recognition (used to construct visual-span profiles), and deployment of ...

Impact of low vision rehabilitation on functional vision performance of children with visual impairment.

Science.gov (United States)

Ganesh, Suma; Sethi, Sumita; Srivastav, Sonia; Chaudhary, Amrita; Arora, Priyanka

2013-09-01

To evaluate the impact of low vision rehabilitation on functional vision of children with visual impairment. The LV Prasad-Functional Vision Questionnaire, designed specifically to measure functional performance of visually impaired children of developing countries, was used to assess the level of difficulty in performing various tasks pre and post visual rehabilitation in children with documented visual impairment. Chi-square test was used to assess the impact of rehabilitation intervention on functional vision performance; a P visual acuity prior to the introduction of low vision devices (LVDs) was 0.90 ± 0.05 for distance and for near it was 0.61 ± 0.05. After the intervention, the acuities improved significantly for distance (0.2 ± 0.27; P visual rehabilitation was especially found in those activities related to their studying lifestyle like copying from the blackboard (P visual rehabilitation, especially with those activities which are related to their academic output. It is important for these children to have an early visual rehabilitation to decrease the impairment associated with these decreased visual output and to enhance their learning abilities.

Evaluation of Tc-99M dextran as a useful agent for peripheral lymphoscintigraphy

International Nuclear Information System (INIS)

Farzana Kousar; Muhammad Numair Younis; Shabana Saeed; Mustanser Jehangir; Saeeda Asghar

2004-01-01

Peripheral lymphoscintigraphy is known for its great academic value and more importantly, may contribute to supporting the accuracy of clinical diagnosis and assessment of lymphedema treatment. The main aim of this study was to evaluate the 99m Tc dextran as peripheral lymphoscintigraphic agent and its validation in recognizing different lymphatic patterns in normal and edematous limbs. Methods: Peripheral lymphoscintigraphy was performed in 24 patients (mean age 43.9 ± 11 years) using 99m Tc dextran (molecular weight 150,000 and 250,000) as radiotracer. 37 MBq (1 mCi) 99m Tc dextran (PINSCANTM) was injected intradermally in the first web space of the hand or foot of both limbs. 30 minutes sequential dynamic and static imaging was done. Delayed static images were taken at one hour and then three hours post injection. Results: Only qualitative interpretation was done. Different lymphatic patterns were observed in normal population as well as in control and edematous limbs. Results were further analysed using chi square test, paired and unpaired student t test at the confidence level 0.05. All mean values were given with one standard deviation. Visual and statistical analysis showed good clinical correlation. These results were also compared favourably with 99m Tc HSA lymphoscintigraphic findings available in literature. Conclusion: 99m Tc dextran is a promising agent for peripheral lymphoscintigraphy. (authors)

How visual search relates to visual diagnostic performance : a narrative systematic review of eye-tracking research in radiology

NARCIS (Netherlands)

van der Gijp, A; Ravesloot, C J; Jarodzka, H; van der Schaaf, M F; van der Schaaf, I C; van Schaik, J P J; ten Cate, Olle

Eye tracking research has been conducted for decades to gain understanding of visual diagnosis such as in radiology. For educational purposes, it is important to identify visual search patterns that are related to high perceptual performance and to identify effective teaching strategies. This review

Formation of 17-18 yrs age girl students’ visual performance by means of visual training at stage of adaptation to learning loads

Directory of Open Access Journals (Sweden)

Bondarenko S.V.

2015-04-01

Full Text Available Purpose: substantiation of health related training influence of basketball and volleyball elements on functional state of 1 st year students’ visual analyzers in period of adaptation to learning loads with expressed visual component. Material: in experiment 29 students of 17-18 year age without visual pathologies participated. Indicators of visual performance were determined by correction table of Tagayeva and processed by Weston methodic. Accommodative function was tested by method of mechanical proximetry. Results: the authors worked out and tested two programs of visual training. Influence of visual trainings on visual performance’s main components (quickness, quality, integral indicators was studied as well as eye’s accommodative function (by dynamic of position of the nearest point of clear vision. Conclusions: Application of visual trainings at physical education classes permits to improve indicators of visual analyzer’s performance as well as minimize negative influence of intensive learning loads on eye’ accommodative function.

Positive mood broadens visual attention to positive stimuli.

Science.gov (United States)

Wadlinger, Heather A; Isaacowitz, Derek M

2006-03-01

In an attempt to investigate the impact of positive emotions on visual attention within the context of Fredrickson's (1998) broaden-and-build model, eye tracking was used in two studies to measure visual attentional preferences of college students (n=58, n=26) to emotional pictures. Half of each sample experienced induced positive mood immediately before viewing slides of three similarly-valenced images, in varying central-peripheral arrays. Attentional breadth was determined by measuring the percentage viewing time to peripheral images as well as by the number of visual saccades participants made per slide. Consistent with Fredrickson's theory, the first study showed that individuals induced into positive mood fixated more on peripheral stimuli than did control participants; however, this only held true for highly-valenced positive stimuli. Participants under induced positive mood also made more frequent saccades for slides of neutral and positive valence. A second study showed that these effects were not simply due to differences in emotional arousal between stimuli. Selective attentional broadening to positive stimuli may act both to facilitate later building of resources as well as to maintain current positive affective states.

Brain activity during auditory and visual phonological, spatial and simple discrimination tasks.

Science.gov (United States)

Salo, Emma; Rinne, Teemu; Salonen, Oili; Alho, Kimmo

2013-02-16

We used functional magnetic resonance imaging to measure human brain activity during tasks demanding selective attention to auditory or visual stimuli delivered in concurrent streams. Auditory stimuli were syllables spoken by different voices and occurring in central or peripheral space. Visual stimuli were centrally or more peripherally presented letters in darker or lighter fonts. The participants performed a phonological, spatial or "simple" (speaker-gender or font-shade) discrimination task in either modality. Within each modality, we expected a clear distinction between brain activations related to nonspatial and spatial processing, as reported in previous studies. However, within each modality, different tasks activated largely overlapping areas in modality-specific (auditory and visual) cortices, as well as in the parietal and frontal brain regions. These overlaps may be due to effects of attention common for all three tasks within each modality or interaction of processing task-relevant features and varying task-irrelevant features in the attended-modality stimuli. Nevertheless, brain activations caused by auditory and visual phonological tasks overlapped in the left mid-lateral prefrontal cortex, while those caused by the auditory and visual spatial tasks overlapped in the inferior parietal cortex. These overlapping activations reveal areas of multimodal phonological and spatial processing. There was also some evidence for intermodal attention-related interaction. Most importantly, activity in the superior temporal sulcus elicited by unattended speech sounds was attenuated during the visual phonological task in comparison with the other visual tasks. This effect might be related to suppression of processing irrelevant speech presumably distracting the phonological task involving the letters. Copyright © 2012 Elsevier B.V. All rights reserved.

Intraoperative Ultrasound for Peripheral Nerve Applications.

Science.gov (United States)

Willsey, Matthew; Wilson, Thomas J; Henning, Phillip Troy; Yang, Lynda J-S

2017-10-01

Offering real-time, high-resolution images via intraoperative ultrasound is advantageous for a variety of peripheral nerve applications. To highlight the advantages of ultrasound, its extraoperative uses are reviewed. The current intraoperative uses, including nerve localization, real-time evaluation of peripheral nerve tumors, and implantation of leads for peripheral nerve stimulation, are reviewed. Although intraoperative peripheral nerve localization has been performed previously using guide wires and surgical dyes, the authors' approach using ultrasound-guided instrument clamps helps guide surgical dissection to the target nerve, which could lead to more timely operations and shorter incisions. Copyright © 2017 Elsevier Inc. All rights reserved.

[Atherectomy for peripheral arterial disease].

Science.gov (United States)

Londero, Louise Skovgaard; Høgh, Annette Langager; Lindholt, Jes Sanddal

2015-04-13

Symptomatic peripheral arterial disease is managed according to national and international guidelines and the number of vascular reconstructions performed each year has increased over the past decade mainly due to an increasing frequency of endovascular procedures. Atherectomy as an alternative to the established treatment of symptomatic peripheral arterial disease has recently been analysed in a Cochrane review. In Denmark, atherectomy is not performed and so far the evidence is poor as the method is not an alternative to the established treatment in this country.

Visual function and color vision in adults with Attention-Deficit/Hyperactivity Disorder.

Science.gov (United States)

Kim, Soyeon; Chen, Samantha; Tannock, Rosemary

2014-01-01

Color vision and self-reported visual function in everyday life in young adults with Attention-Deficit/Hyperactivity Disorder (ADHD) were investigated. Participants were 30 young adults with ADHD and 30 controls matched for age and gender. They were tested individually and completed the Visual Activities Questionnaire (VAQ), Farnsworth-Munsell 100 Hue Test (FMT) and A Quick Test of Cognitive Speed (AQT). The ADHD group reported significantly more problems in 4 of 8 areas on the VAQ: depth perception, peripheral vision, visual search and visual processing speed. Further analyses of VAQ items revealed that the ADHD group endorsed more visual problems associated with driving than controls. Color perception difficulties on the FMT were restricted to the blue spectrum in the ADHD group. FMT and AQT results revealed slower processing of visual stimuli in the ADHD group. A comprehensive investigation of mechanisms underlying visual function and color vision in adults with ADHD is warranted, along with the potential impact of these visual problems on driving performance. Copyright © 2013 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Optical and visual performance of aspheric soft contact lenses.

Science.gov (United States)

Efron, Suzanne; Efron, Nathan; Morgan, Philip B

2008-03-01

This study was conducted to investigate whether aspheric design soft contact lenses reduce ocular aberrations and result in better visual acuity and subjective appreciation of clinical performance compared with spherical soft contact lenses. A unilateral, double-masked, randomized and controlled study was undertaken in which ocular aberrations and high and low contrast logMAR visual acuity were measured on myopic subjects who wore aspheric design (Biomedics 55 Evolution, CooperVision) and spherical design (Biomedics 55, CooperVision) soft contact lenses. Ten subjects who had about -2.00 D myopia wore -2.00 D lenses and 10 subjects who had about -5.00 D myopia wore -5.00 D lenses. Measurements were made under photopic and mesopic lighting conditions. Subjects were invited to grade comfort, vision in photopic and mesopic conditions, and overall impression with the two lens types on 100 unit visual analogue scales. There was no significant difference in high contrast or low contrast visual acuity between the two lens designs of either power under photopic or mesopic conditions. Both lens designs displayed lower levels of spherical aberration compared with the "no lens" condition under photopic and mesopic light levels (p designs. There were no statistically significant differences in subjective appreciation of clinical performance between lens designs or lens powers. At least with respect to the brand of lenses tested, the fitting of aspheric design soft contact lenses does not result in superior visual acuity, aberration control, or subjective appreciation compared with equivalent spherical design soft contact lenses.

Peripherally applied opioids for postoperative pain

DEFF Research Database (Denmark)

Nielsen, B N; Henneberg, S W; Schmiegelow, K

2015-01-01

BACKGROUND: Opioids applied peripherally at the site of surgery may produce postoperative analgesia with few side effects. We performed this systematic review to evaluate the analgesic effect of peripherally applied opioids for acute postoperative pain. METHODS: We searched PubMed (1966 to June...... 2013), Embase (1980 to June 2013), and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 6). Randomized controlled trials investigating the postoperative analgesic effect of peripherally applied opioids vs. systemic opioids or placebo, measured by pain intensity...... difference -5 mm, 95% CI: -7 to -3) for peripherally applied opioids vs. placebo and statistically significant increased time to first analgesic (mean difference 153 min, 95% CI: 41-265). When preoperative inflammation was reported (five studies), peripherally applied opioids significantly improved...

Anticipatory alpha phase influences visual working memory performance.

Science.gov (United States)

Zanto, Theodore P; Chadick, James Z; Gazzaley, Adam

2014-01-15

Alpha band (8-12 Hz) phase dynamics in the visual cortex are thought to reflect fluctuations in cortical excitability that influences perceptual processing. As such, visual stimuli are better detected when their onset is concurrent with specific phases of the alpha cycle. However, it is unclear whether alpha phase differentially influences cognitive performance at specific times relative to stimulus onset (i.e., is the influence of phase maximal before, at, or after stimulus onset?). To address this, participants performed a delayed-recognition, working memory (WM) task for visual motion direction during two separate visits. The first visit utilized functional magnetic resonance (fMRI) imaging to identify neural regions associated with task performance. Replicating previous studies, fMRI data showed engagement of visual cortical area V5, as well as a prefrontal cortical region, the inferior frontal junction (IFJ). During the second visit, transcranial magnetic stimulation (TMS) was applied separately to both the right IFJ and right V5 (with the vertex as a control region) while electroencephalography (EEG) was simultaneously recorded. During each trial, a single pulse of TMS (spTMS) was applied at one of six time points (-200, -100, -50, 0, 80, 160 ms) relative to the encoded stimulus onset. Results demonstrated a relationship between the phase of the posterior alpha signal prior to stimulus encoding and subsequent response times to the memory probe two seconds later. Specifically, spTMS to V5, and not the IFJ or vertex, yielded faster response times, indicating improved WM performance, when delivered during the peak, compared to the trough, of the alpha cycle, but only when spTMS was applied 100 ms prior to stimulus onset. These faster responses to the probe correlated with decreased early event related potential (ERP) amplitudes (i.e., P1) to the probe stimuli. Moreover, participants that were least affected by spTMS exhibited greater functional connectivity

Peripheral venous catheter insertion simulation training: A randomized controlled trial comparing performance after instructor-led teaching versus peer-assisted learning.

Science.gov (United States)

Pelloux, Sophie; Grégoire, Arnaud; Kirmizigul, Patrice; Maillot, Sandrine; Bui-Xuan, Bernard; Llorca, Guy; Boet, Sylvain; Lehot, Jean-Jacques; Rimmelé, Thomas

2017-12-01

Peripheral venous catheter insertion is a procedural skill that every medical student should master. Training is often limited to a small number of students and is poorly evaluated. The objective of this study was to evaluate the performance of peer-assisted learning in comparison to instructor-led teaching for peripheral venous catheter insertion training. Students were randomized to the control group attending a traditional instructor-led training session (slideshow and demonstration by an anesthetist instructor, followed by training on a procedural simulator) or to the test group attending a peer-assisted training session (slideshow and demonstration video-recorded by the same instructor, followed by training on a procedural simulator). The primary endpoint was the performance of peripheral venous catheter insertion, assessed on procedural simulator one week later by blinded experts using a standardized 20-item grid. Students self-evaluated their confidence levels using a numeric 10-point scale. Eighty-six students were included, 73 of whom attended the assessment session. The median performance score was 12/20 [8-15] in the instructor-led teaching group versus 13/20 [11-15] in the peer-assisted learning group (P=0.430). Confidence levels improved significantly after the assessment session and were significantly higher in the peer-assisted learning group (7.6/10 [7.0-8.0] versus 7.0/10 [5.0-8.0], P=0.026). Peer-assisted learning is effective for peripheral venous catheter insertion training and can be as effective as instructor-led teaching. Given the large number of students to train, this finding is important for optimizing the cost-effectiveness of peripheral venous catheter insertion training. Copyright © 2017 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

Unsold is unseen … or is it? Examining the role of peripheral vision in the consumer choice process using eye-tracking methodology.

Science.gov (United States)

Wästlund, Erik; Shams, Poja; Otterbring, Tobias

2018-01-01

In visual marketing, the truism that "unseen is unsold" means that products that are not noticed will not be sold. This truism rests on the idea that the consumer choice process is heavily influenced by visual search. However, given that the majority of available products are not seen by consumers, this article examines the role of peripheral vision in guiding attention during the consumer choice process. In two eye-tracking studies, one conducted in a lab facility and the other conducted in a supermarket, the authors investigate the role and limitations of peripheral vision. The results show that peripheral vision is used to direct visual attention when discriminating between target and non-target objects in an eye-tracking laboratory. Target and non-target similarity, as well as visual saliency of non-targets, constitute the boundary conditions for this effect, which generalizes from instruction-based laboratory tasks to preference-based choice tasks in a real supermarket setting. Thus, peripheral vision helps customers to devote a larger share of attention to relevant products during the consumer choice process. Taken together, the results show how the creation of consideration set (sets of possible choice options) relies on both goal-directed attention and peripheral vision. These results could explain how visually similar packaging positively influences market leaders, while making novel brands almost invisible on supermarket shelves. The findings show that even though unsold products might be unseen, in the sense that they have not been directly observed, they might still have been evaluated and excluded by means of peripheral vision. This article is based on controlled lab experiments as well as a field study conducted in a complex retail environment. Thus, the findings are valid both under controlled and ecologically valid conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Angioplasty and stent placement - peripheral arteries - discharge

Science.gov (United States)

... medlineplus.gov/ency/patientinstructions/000234.htm Angioplasty and stent placement - peripheral arteries - discharge To use the sharing ... peripheral artery). You may have also had a stent placed. To perform the procedure: Your doctor inserted ...

Visual performance of pigeons following hippocampal lesions.

Science.gov (United States)

Bingman, V P; Hodos, W

1992-11-15

The effect of hippocampal lesions on performance in two psychophysical measures of spatial vision (acuity and size-difference threshold) was examined in 7 pigeons. No difference between the preoperative and postoperative thresholds of the experimental birds was found. The visual performance of pigeons in the psychophysical tasks failed to reveal a role of the hippocampal formation in vision. The results argue strongly that the behavioral deficits found in pigeons with hippocampal lesions when tested in a variety of memory-related spatial tasks is not based on a defect in spatial vision but impaired spatial cognition.

Influence of combined visual and vestibular cues on human perception and control of horizontal rotation

Science.gov (United States)

Zacharias, G. L.; Young, L. R.

1981-01-01

Measurements are made of manual control performance in the closed-loop task of nulling perceived self-rotation velocity about an earth-vertical axis. Self-velocity estimation is modeled as a function of the simultaneous presentation of vestibular and peripheral visual field motion cues. Based on measured low-frequency operator behavior in three visual field environments, a parallel channel linear model is proposed which has separate visual and vestibular pathways summing in a complementary manner. A dual-input describing function analysis supports the complementary model; vestibular cues dominate sensation at higher frequencies. The describing function model is extended by the proposal of a nonlinear cue conflict model, in which cue weighting depends on the level of agreement between visual and vestibular cues.

How Visual Search Relates to Visual Diagnostic Performance: A Narrative Systematic Review of Eye-Tracking Research in Radiology

Science.gov (United States)

van der Gijp, A.; Ravesloot, C. J.; Jarodzka, H.; van der Schaaf, M. F.; van der Schaaf, I. C.; van Schaik, J. P.; ten Cate, Th. J.

2017-01-01

Eye tracking research has been conducted for decades to gain understanding of visual diagnosis such as in radiology. For educational purposes, it is important to identify visual search patterns that are related to high perceptual performance and to identify effective teaching strategies. This review of eye-tracking literature in the radiology…

Aurally Aided Visual Search Performance Comparing Virtual Audio Systems

DEFF Research Database (Denmark)

Larsen, Camilla Horne; Lauritsen, David Skødt; Larsen, Jacob Junker

2014-01-01

Due to increased computational power, reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between a HRTF enhanced audio system (3D) and an...... with white dots. The results indicate that 3D audio yields faster search latencies than panning audio, especially with larger amounts of distractors. The applications of this research could fit virtual environments such as video games or virtual simulations.......Due to increased computational power, reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between a HRTF enhanced audio system (3D...

Aurally Aided Visual Search Performance Comparing Virtual Audio Systems

DEFF Research Database (Denmark)

Larsen, Camilla Horne; Lauritsen, David Skødt; Larsen, Jacob Junker

2014-01-01

Due to increased computational power reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between an HRTF enhanced audio system (3D) and an...... with white dots. The results indicate that 3D audio yields faster search latencies than panning audio, especially with larger amounts of distractors. The applications of this research could fit virtual environments such as video games or virtual simulations.......Due to increased computational power reproducing binaural hearing in real-time applications, through usage of head-related transfer functions (HRTFs), is now possible. This paper addresses the differences in aurally-aided visual search performance between an HRTF enhanced audio system (3D...

Effect of Cognitive Demand on Functional Visual Field Performance in Senior Drivers with Glaucoma

Directory of Open Access Journals (Sweden)

Viswa Gangeddula

2017-08-01

Full Text Available Purpose: To investigate the effect of cognitive demand on functional visual field performance in drivers with glaucoma.Method: This study included 20 drivers with open-angle glaucoma and 13 age- and sex-matched controls. Visual field performance was evaluated under different degrees of cognitive demand: a static visual field condition (C1, dynamic visual field condition (C2, and dynamic visual field condition with active driving (C3 using an interactive, desktop driving simulator. The number of correct responses (accuracy and response times on the visual field task were compared between groups and between conditions using Kruskal–Wallis tests. General linear models were employed to compare cognitive workload, recorded in real-time through pupillometry, between groups and conditions.Results: Adding cognitive demand (C2 and C3 to the static visual field test (C1 adversely affected accuracy and response times, in both groups (p < 0.05. However, drivers with glaucoma performed worse than did control drivers when the static condition changed to a dynamic condition [C2 vs. C1 accuracy; glaucoma: median difference (Q1–Q3 3 (2–6.50 vs. controls: 2 (0.50–2.50; p = 0.05] and to a dynamic condition with active driving [C3 vs. C1 accuracy; glaucoma: 2 (2–6 vs. controls: 1 (0.50–2; p = 0.02]. Overall, drivers with glaucoma exhibited greater cognitive workload than controls (p = 0.02.Conclusion: Cognitive demand disproportionately affects functional visual field performance in drivers with glaucoma. Our results may inform the development of a performance-based visual field test for drivers with glaucoma.

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

International Nuclear Information System (INIS)

Tsoumakidou, Georgia; Garnon, Julien; Ramamurthy, Nitin; Buy, Xavier; Gangi, Afshin

2013-01-01

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO 2 insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation

Energy Technology Data Exchange (ETDEWEB)

Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)

2013-12-15

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

Visualizations of Travel Time Performance Based on Vehicle Reidentification Data

Energy Technology Data Exchange (ETDEWEB)

Young, Stanley Ernest [National Renewable Energy Lab, 15013 Denver West Parkway, Golden, CO 80401; Sharifi, Elham [Center for Advanced Transportation Technology, University of Maryland, College Park, Technology Ventures Building, Suite 2200, 5000 College Avenue, College Park, MD 20742; Day, Christopher M. [Joint Transportation Research Program, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906; Bullock, Darcy M. [Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47906

2017-01-01

This paper provides a visual reference of the breadth of arterial performance phenomena based on travel time measures obtained from reidentification technology that has proliferated in the past 5 years. These graphical performance measures are revealed through overlay charts and statistical distribution as revealed through cumulative frequency diagrams (CFDs). With overlays of vehicle travel times from multiple days, dominant traffic patterns over a 24-h period are reinforced and reveal the traffic behavior induced primarily by the operation of traffic control at signalized intersections. A cumulative distribution function in the statistical literature provides a method for comparing traffic patterns from various time frames or locations in a compact visual format that provides intuitive feedback on arterial performance. The CFD may be accumulated hourly, by peak periods, or by time periods specific to signal timing plans that are in effect. Combined, overlay charts and CFDs provide visual tools with which to assess the quality and consistency of traffic movement for various periods throughout the day efficiently, without sacrificing detail, which is a typical byproduct of numeric-based performance measures. These methods are particularly effective for comparing before-and-after median travel times, as well as changes in interquartile range, to assess travel time reliability.

Measuring the performance of visual to auditory information conversion.

Directory of Open Access Journals (Sweden)

Shern Shiou Tan

Full Text Available BACKGROUND: Visual to auditory conversion systems have been in existence for several decades. Besides being among the front runners in providing visual capabilities to blind users, the auditory cues generated from image sonification systems are still easier to learn and adapt to compared to other similar techniques. Other advantages include low cost, easy customizability, and universality. However, every system developed so far has its own set of strengths and weaknesses. In order to improve these systems further, we propose an automated and quantitative method to measure the performance of such systems. With these quantitative measurements, it is possible to gauge the relative strengths and weaknesses of different systems and rank the systems accordingly. METHODOLOGY: Performance is measured by both the interpretability and also the information preservation of visual to auditory conversions. Interpretability is measured by computing the correlation of inter image distance (IID and inter sound distance (ISD whereas the information preservation is computed by applying Information Theory to measure the entropy of both visual and corresponding auditory signals. These measurements provide a basis and some insights on how the systems work. CONCLUSIONS: With an automated interpretability measure as a standard, more image sonification systems can be developed, compared, and then improved. Even though the measure does not test systems as thoroughly as carefully designed psychological experiments, a quantitative measurement like the one proposed here can compare systems to a certain degree without incurring much cost. Underlying this research is the hope that a major breakthrough in image sonification systems will allow blind users to cost effectively regain enough visual functions to allow them to lead secure and productive lives.

Visualization and Analysis of Climate Simulation Performance Data

Science.gov (United States)

Röber, Niklas; Adamidis, Panagiotis; Behrens, Jörg

2015-04-01

Visualization is the key process of transforming abstract (scientific) data into a graphical representation, to aid in the understanding of the information hidden within the data. Climate simulation data sets are typically quite large, time varying, and consist of many different variables sampled on an underlying grid. A large variety of climate models - and sub models - exist to simulate various aspects of the climate system. Generally, one is mainly interested in the physical variables produced by the simulation runs, but model developers are also interested in performance data measured along with these simulations. Climate simulation models are carefully developed complex software systems, designed to run in parallel on large HPC systems. An important goal thereby is to utilize the entire hardware as efficiently as possible, that is, to distribute the workload as even as possible among the individual components. This is a very challenging task, and detailed performance data, such as timings, cache misses etc. have to be used to locate and understand performance problems in order to optimize the model implementation. Furthermore, the correlation of performance data to the processes of the application and the sub-domains of the decomposed underlying grid is vital when addressing communication and load imbalance issues. High resolution climate simulations are carried out on tens to hundreds of thousands of cores, thus yielding a vast amount of profiling data, which cannot be analyzed without appropriate visualization techniques. This PICO presentation displays and discusses the ICON simulation model, which is jointly developed by the Max Planck Institute for Meteorology and the German Weather Service and in partnership with DKRZ. The visualization and analysis of the models performance data allows us to optimize and fine tune the model, as well as to understand its execution on the HPC system. We show and discuss our workflow, as well as present new ideas and

Effect of different illumination sources on reading and visual performance

Directory of Open Access Journals (Sweden)

Male Shiva Ram

2018-01-01

Conclusion: This study demonstrates the influence of illumination on reading rate; there were no significant differences between males and females under different illuminations, however, males preferred CFL and females preferred FLUO for faster reading and visual comfort. Interestingly, neither preferred LED or TUNG. Although energy-efficient, visual performance under LED is poor; it is uncomfortable for prolonged reading and causes early symptoms of fatigue.

Visual art teachers and performance assessment methods in ...

African Journals Online (AJOL)

This paper examines the competencies of visual arts teachers in using performance assessment methods, and to ascertain the extent to which the knowledge, skills and experiences of teachers affect their competence in using assessment strategies in their classroom. The study employs a qualitative research design; ...

Enhanced Massive Visualization of Engines Performance

International Nuclear Information System (INIS)

Rostand, N D; Eglantine, H; Jerôme, L

2012-01-01

Today, we are witnessing an increasing complexity of transport in order to deal with requirements of safety, security, reliability and efficiency. Such transport is generally equipped with drive systems; it is nevertheless for engine manufacturers to overcome the performance requirements of energy efficiency throughout their operations. To this end, this article proposes a performance monitoring solution for a large fleet of engines in operation. It uses a pre-calibrated physical model developed by the engine manufacturer regarding the performance objectives as reference. The physical model is firstly decomposed into critical performance modules, and is secondly updated on current observations extracted at specific predefined operating conditions in order to derive residual errors status of each engine tested. Through a process of standardization of those contextual differences remaining, the solution offers a synthesis mapping to visualize the evolution of performance of each engine throughout its operations. This article describes the theoretical methodology of implementation mainly based on universal mathematical foundations, and vindicates the interests of its industrialization in the light of the proactive findings.

Oregon State University Softball: Dynamic Visual Acuity Training for Improving Performance

OpenAIRE

Madsen, Bruce; Blair, Kyle

2017-01-01

Sports vision training involves eye focusing and movement workouts that center on the visual tracking of objects. The purpose of sports vision training is to improve performance in various sports by improving visual responses and processing, such as by lowering reaction times. In 2015, the Athletic Eye Institute started a sports vision-training program study with the Oregon State University Softball Team in the hopes of increasing the dynamic visual skills of their players. There were two aim...

Influence of visual feedback on human task performance in ITER remote handling

Energy Technology Data Exchange (ETDEWEB)

Schropp, Gwendolijn Y.R., E-mail: g.schropp@heemskerk-innovative.nl [Utrecht University, Utrecht (Netherlands); Heemskerk Innovative Technology, Noordwijk (Netherlands); Heemskerk, Cock J.M. [Heemskerk Innovative Technology, Noordwijk (Netherlands); Kappers, Astrid M.L.; Tiest, Wouter M. Bergmann [Helmholtz Institute-Utrecht University, Utrecht (Netherlands); Elzendoorn, Ben S.Q. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM/FOM, Partner in the Trilateral Euregio Clusterand ITER-NL, PO box 1207, 3430 BE Nieuwegein (Netherlands); Bult, David [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM/FOM, Partner in the Trilateral Euregio Clusterand ITER-NL, PO box 1207, 3430 BE Nieuwegein (Netherlands)

2012-08-15

Highlights: Black-Right-Pointing-Pointer The performance of human operators in an ITER-like test facility for remote handling. Black-Right-Pointing-Pointer Different sources of visual feedback influence how fast one can complete a maintenance task. Black-Right-Pointing-Pointer Insights learned could be used in design of operator work environment or training procedures. - Abstract: In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures. Additional verification and validation is based on simulation and hardware tests in 1:1 scale mockups. The Master Slave manipulator system (MS2) Benchmark Product was designed to implement a reference set of maintenance tasks representative for ITER remote handling. Experiments were performed with two versions of the Benchmark Product. In both experiments, the quality of visual feedback varied by exchanging direct view with indirect view (using video cameras) in order to measure and analyze its impact on human task performance. The first experiment showed that both experienced and novice RH operators perform a simple task significantly better with direct visual feedback than with camera feedback. A more complex task showed a large variation in results and could not be completed by many novice operators. Experienced operators commented on both the mechanical design and visual feedback. In a second experiment, a more elaborate task was tested on an improved Benchmark product. Again, the task was performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.

Influence of visual feedback on human task performance in ITER remote handling

International Nuclear Information System (INIS)

Schropp, Gwendolijn Y.R.; Heemskerk, Cock J.M.; Kappers, Astrid M.L.; Tiest, Wouter M. Bergmann; Elzendoorn, Ben S.Q.; Bult, David

2012-01-01

Highlights: ► The performance of human operators in an ITER-like test facility for remote handling. ► Different sources of visual feedback influence how fast one can complete a maintenance task. ► Insights learned could be used in design of operator work environment or training procedures. - Abstract: In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures. Additional verification and validation is based on simulation and hardware tests in 1:1 scale mockups. The Master Slave manipulator system (MS2) Benchmark Product was designed to implement a reference set of maintenance tasks representative for ITER remote handling. Experiments were performed with two versions of the Benchmark Product. In both experiments, the quality of visual feedback varied by exchanging direct view with indirect view (using video cameras) in order to measure and analyze its impact on human task performance. The first experiment showed that both experienced and novice RH operators perform a simple task significantly better with direct visual feedback than with camera feedback. A more complex task showed a large variation in results and could not be completed by many novice operators. Experienced operators commented on both the mechanical design and visual feedback. In a second experiment, a more elaborate task was tested on an improved Benchmark product. Again, the task was performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.

Visual Analysis of Cloud Computing Performance Using Behavioral Lines.

Science.gov (United States)

Muelder, Chris; Zhu, Biao; Chen, Wei; Zhang, Hongxin; Ma, Kwan-Liu

2016-02-29

Cloud computing is an essential technology to Big Data analytics and services. A cloud computing system is often comprised of a large number of parallel computing and storage devices. Monitoring the usage and performance of such a system is important for efficient operations, maintenance, and security. Tracing every application on a large cloud system is untenable due to scale and privacy issues. But profile data can be collected relatively efficiently by regularly sampling the state of the system, including properties such as CPU load, memory usage, network usage, and others, creating a set of multivariate time series for each system. Adequate tools for studying such large-scale, multidimensional data are lacking. In this paper, we present a visual based analysis approach to understanding and analyzing the performance and behavior of cloud computing systems. Our design is based on similarity measures and a layout method to portray the behavior of each compute node over time. When visualizing a large number of behavioral lines together, distinct patterns often appear suggesting particular types of performance bottleneck. The resulting system provides multiple linked views, which allow the user to interactively explore the data by examining the data or a selected subset at different levels of detail. Our case studies, which use datasets collected from two different cloud systems, show that this visual based approach is effective in identifying trends and anomalies of the systems.

Peripheral neuropathy

Science.gov (United States)

... peripheral; Neuritis - peripheral; Nerve disease; Polyneuropathy; Chronic pain - peripheral neuropathy ... Philadelphia, PA: Elsevier; 2016:chap 107. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

From Big Data to Big Displays High-Performance Visualization at Blue Brain

KAUST Repository

Eilemann, Stefan; Abdellah, Marwan; Antille, Nicolas; Bilgili, Ahmet; Chevtchenko, Grigory; Dumusc, Raphael; Favreau, Cyrille; Hernando, Juan; Nachbaur, Daniel; Podhajski, Pawel; Villafranca, Jafet; Schü rmann, Felix

2017-01-01

Blue Brain has pushed high-performance visualization (HPV) to complement its HPC strategy since its inception in 2007. In 2011, this strategy has been accelerated to develop innovative visualization solutions through increased funding and strategic

BDNF Variants May Modulate Long-Term Visual Memory Performance in a Healthy Cohort.

Science.gov (United States)

Avgan, Nesli; Sutherland, Heidi G; Spriggens, Lauren K; Yu, Chieh; Ibrahim, Omar; Bellis, Claire; Haupt, Larisa M; Shum, David H K; Griffiths, Lyn R

2017-03-17

Brain-derived neurotrophic factor (BDNF) is involved in numerous cognitive functions including learning and memory. BDNF plays an important role in synaptic plasticity in humans and rats with BDNF shown to be essential for the formation of long-term memories. We previously identified a significant association between the BDNF Val66Met polymorphism (rs6265) and long-term visual memory ( p -value = 0.003) in a small cohort ( n = 181) comprised of healthy individuals who had been phenotyped for various aspects of memory function. In this study, we have extended the cohort to 597 individuals and examined multiple genetic variants across both the BDNF and BDNF-AS genes for association with visual memory performance as assessed by the Wechsler Memory Scale-Fourth Edition subtests Visual Reproduction I and II (VR I and II). VR I assesses immediate visual memory, whereas VR II assesses long-term visual memory. Genetic association analyses were performed for 34 single nucleotide polymorphisms genotyped on Illumina OmniExpress BeadChip arrays with the immediate and long-term visual memory phenotypes. While none of the BDNF and BDNF-AS variants were shown to be significant for immediate visual memory, we found 10 variants (including the Val66Met polymorphism ( p -value = 0.006)) that were nominally associated, and three variants (two variants in BDNF and one variant in the BDNF-AS locus) that were significantly associated with long-term visual memory. Our data therefore suggests a potential role for BDNF , and its anti-sense transcript BDNF-AS , in long-term visual memory performance.

BDNF Variants May Modulate Long-Term Visual Memory Performance in a Healthy Cohort

Directory of Open Access Journals (Sweden)

Nesli Avgan

2017-03-01

Full Text Available Brain-derived neurotrophic factor (BDNF is involved in numerous cognitive functions including learning and memory. BDNF plays an important role in synaptic plasticity in humans and rats with BDNF shown to be essential for the formation of long-term memories. We previously identified a significant association between the BDNF Val66Met polymorphism (rs6265 and long-term visual memory (p-value = 0.003 in a small cohort (n = 181 comprised of healthy individuals who had been phenotyped for various aspects of memory function. In this study, we have extended the cohort to 597 individuals and examined multiple genetic variants across both the BDNF and BDNF-AS genes for association with visual memory performance as assessed by the Wechsler Memory Scale—Fourth Edition subtests Visual Reproduction I and II (VR I and II. VR I assesses immediate visual memory, whereas VR II assesses long-term visual memory. Genetic association analyses were performed for 34 single nucleotide polymorphisms genotyped on Illumina OmniExpress BeadChip arrays with the immediate and long-term visual memory phenotypes. While none of the BDNF and BDNF-AS variants were shown to be significant for immediate visual memory, we found 10 variants (including the Val66Met polymorphism (p-value = 0.006 that were nominally associated, and three variants (two variants in BDNF and one variant in the BDNF-AS locus that were significantly associated with long-term visual memory. Our data therefore suggests a potential role for BDNF, and its anti-sense transcript BDNF-AS, in long-term visual memory performance.

Spatial Scaling of the Profile of Selective Attention in the Visual Field.

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Gannon, Matthew A; Knapp, Ashley A; Adams, Thomas G; Long, Stephanie M; Parks, Nathan A

2016-01-01

Neural mechanisms of selective attention must be capable of adapting to variation in the absolute size of an attended stimulus in the ever-changing visual environment. To date, little is known regarding how attentional selection interacts with fluctuations in the spatial expanse of an attended object. Here, we use event-related potentials (ERPs) to investigate the scaling of attentional enhancement and suppression across the visual field. We measured ERPs while participants performed a task at fixation that varied in its attentional demands (attentional load) and visual angle (1.0° or 2.5°). Observers were presented with a stream of task-relevant stimuli while foveal, parafoveal, and peripheral visual locations were probed by irrelevant distractor stimuli. We found two important effects in the N1 component of visual ERPs. First, N1 modulations to task-relevant stimuli indexed attentional selection of stimuli during the load task and further correlated with task performance. Second, with increased task size, attentional modulation of the N1 to distractor stimuli showed a differential pattern that was consistent with a scaling of attentional selection. Together, these results demonstrate that the size of an attended stimulus scales the profile of attentional selection across the visual field and provides insights into the attentional mechanisms associated with such spatial scaling.

Macular pigment and its contribution to visual performance and experience

Science.gov (United States)

Loughman, James; Davison, Peter A.; Nolan, John M.; Akkali, Mukunda C.; Beatty, Stephen

2010-01-01

There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientific research continues to explore the function(s) of MP in the human retina, with two main hypotheses premised on its putative capacity to (1) protect the retina from (photo)-oxidative damage by means of its optical filtration and/or antioxidant properties, the so-called protective hypothesis and (2) influence the quality of visual performance by means of selective short wavelength light absorption prior to photoreceptor light capture, thereby attenuating the effects of chromatic aberration and light scatter, the so-called acuity and visibility hypotheses. The current epidemic of age-related macular degeneration has directed researchers to investigate the protective hypothesis of MP, while there has been a conspicuous lack of work designed to investigate the role of MP in visual performance. The aim of this review is to present and critically appraise the current literature germane to the contribution of MP, if any, to visual performance and experience.

Macular pigment and its contribution to visual performance and experience

Directory of Open Access Journals (Sweden)

James Loughman

2010-04-01

Full Text Available There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientific research continues to explore the function(s of MP in the human retina, with two main hypotheses premised on its putative capacity to (1 protect the retina from (photo-oxidative damage by means of its optical filtration and/or antioxidant properties, the so-called protective hypothesis and (2 influence the quality of visual performance by means of selective short wavelength light absorption prior to photoreceptor light capture, thereby attenuating the effects of chromatic aberration and light scatter, the so-called acuity and visibility hypotheses. The current epidemic of age-related macular degeneration has directed researchers to investigate the protective hypothesis of MP, while there has been a conspicuous lack of work designed to investigate the role of MP in visual performance. The aim of this review is to present and critically appraise the current literature germane to the contribution of MP, if any, to visual performance and experience.

Burn-related peripheral neuropathy: A systematic review.

Science.gov (United States)

Tu, Yiji; Lineaweaver, William C; Zheng, Xianyou; Chen, Zenggan; Mullins, Fred; Zhang, Feng

2017-06-01

Peripheral neuropathy is the most frequent disabling neuromuscular complication of burns. However, the insidious and progressive onset of burn neuropathy makes it often undiagnosed or overlooked. In our study, we reviewed the current studies on the burn-related peripheral neuropathy to summarize the morbidity, mechanism, detecting method and management of peripheral neuropathy in burn patients. Of the 1533 burn patients included in our study, 98 cases (6.39%) were presented with peripheral neuropathy. Thermal and electrical burns were the most common etiologies. Surgical procedures, especially nerve decompression, showed good effect on functional recovery of both acute and delayed peripheral neuropathy in burn patients. It is noteworthy that, for early detection and prevention of peripheral neuropathy, electrodiagnostic examinations should be performed on burn patients independent of symptoms. Still, the underlying mechanisms of burn-related peripheral neuropathy remain to be clarified. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

High Performance Multivariate Visual Data Exploration for Extremely Large Data

International Nuclear Information System (INIS)

Ruebel, Oliver; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes; Prabhat

2008-01-01

One of the central challenges in modern science is the need to quickly derive knowledge and understanding from large, complex collections of data. We present a new approach that deals with this challenge by combining and extending techniques from high performance visual data analysis and scientific data management. This approach is demonstrated within the context of gaining insight from complex, time-varying datasets produced by a laser wakefield accelerator simulation. Our approach leverages histogram-based parallel coordinates for both visual information display as well as a vehicle for guiding a data mining operation. Data extraction and subsetting are implemented with state-of-the-art index/query technology. This approach, while applied here to accelerator science, is generally applicable to a broad set of science applications, and is implemented in a production-quality visual data analysis infrastructure. We conduct a detailed performance analysis and demonstrate good scalability on a distributed memory Cray XT4 system

High Performance Multivariate Visual Data Exploration for Extremely Large Data

Energy Technology Data Exchange (ETDEWEB)

Rubel, Oliver; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes; Prabhat,

2008-08-22

One of the central challenges in modern science is the need to quickly derive knowledge and understanding from large, complex collections of data. We present a new approach that deals with this challenge by combining and extending techniques from high performance visual data analysis and scientific data management. This approach is demonstrated within the context of gaining insight from complex, time-varying datasets produced by a laser wakefield accelerator simulation. Our approach leverages histogram-based parallel coordinates for both visual information display as well as a vehicle for guiding a data mining operation. Data extraction and subsetting are implemented with state-of-the-art index/query technology. This approach, while applied here to accelerator science, is generally applicable to a broad set of science applications, and is implemented in a production-quality visual data analysis infrastructure. We conduct a detailed performance analysis and demonstrate good scalability on a distributed memory Cray XT4 system.

Cholinergic enhancement reduces orientation-specific surround suppression but not visual crowding

Directory of Open Access Journals (Sweden)

Anna A. Kosovicheva

2012-09-01

Full Text Available Acetylcholine (ACh reduces the spatial spread of excitatory fMRI responses in early visual cortex and the receptive field sizes of V1 neurons. We investigated the perceptual consequences of these physiological effects of ACh with surround suppression and crowding, two tasks that involve spatial interactions between visual field locations. Surround suppression refers to the reduction in perceived stimulus contrast by a high-contrast surround stimulus. For grating stimuli, surround suppression is selective for the relative orientations of the center and surround, suggesting that it results from inhibitory interactions in early visual cortex. Crowding refers to impaired identification of a peripheral stimulus in the presence of flankers and is thought to result from excessive integration of visual features. We increased synaptic ACh levels by administering the cholinesterase inhibitor donepezil to healthy human subjects in a placebo-controlled, double-blind design. In Exp. 1, we measured surround suppression of a central grating using a contrast discrimination task with three conditions: 1 surround grating with the same orientation as the center (parallel, 2 surround orthogonal to the center, or 3 no surround. Contrast discrimination thresholds were higher in the parallel than in the orthogonal condition, demonstrating orientation-specific surround suppression (OSSS. Cholinergic enhancement reduced thresholds only in the parallel condition, thereby reducing OSSS. In Exp. 2, subjects performed a crowding task in which they reported the identity of a peripheral letter flanked by letters on either side. We measured the critical spacing between the target and flanking letters that allowed reliable identification. Cholinergic enhancement had no effect on critical spacing. Our findings suggest that ACh reduces spatial interactions in tasks involving segmentation of visual field locations but that these effects may be limited to early visual cortical

Adipose-Derived Stem Cells Promote Peripheral Nerve Regeneration In Vivo without Differentiation into Schwann-Like Lineage.

Science.gov (United States)

Sowa, Yoshihiro; Kishida, Tsunao; Imura, Tetsuya; Numajiri, Toshiaki; Nishino, Kenichi; Tabata, Yasuhiko; Mazda, Osam

2016-02-01

During recent decades, multipotent stem cells were found to reside in the adipose tissue, and these adipose-derived stem cells were shown to play beneficial roles, like those of Schwann cells, in peripheral nerve regeneration. However, it has not been well established whether adipose-derived stem cells offer beneficial effects to peripheral nerve injuries in vivo as Schwann cells do. Furthermore, the in situ survival and differentiation of adipose-derived stem cells after transplantation at the injured peripheral nerve tissue remain to be fully elucidated. Adipose-derived stem cells and Schwann cells were transplanted with gelatin hydrogel tubes at the artificially blunted sciatic nerve lesion in mice. Neuroregenerative abilities of them were comparably estimated. Cre-loxP-mediated fate tracking was performed to visualize survival in vivo of transplanted adipose-derived stem cells and to investigate whether they differentiated into Schwann linage cells at the peripheral nerve injury site. The transplantation of adipose-derived stem cells promoted regeneration of axons, formation of myelin, and restoration of denervation muscle atrophy to levels comparable to those achieved by Schwann cell transplantation. The adipose-derived stem cells survived for at least 4 weeks after transplantation without differentiating into Schwann cells. Transplanted adipose-derived stem cells did not differentiate into Schwann cells but promoted peripheral nerve regeneration at the injured site. The neuroregenerative ability was comparable to that of Schwann cells. Adipose-derived stem cells at an undifferentiated stage may be used as an alternative cell source for autologous cell therapy for patients with peripheral nerve injury.

The body voyage as visual representation and art performance

DEFF Research Database (Denmark)

Olsén, Jan-Eric

2011-01-01

This paper looks at the notion of the body as an interior landscape that is made intelligible through visual representation. It discerns the key figure of the inner corporeal voyage, identifies its main elements and examines how contemporary artists working with performances and installations deal...... with it. A further aim with the paper is to discuss what kind of image of the body that is conveyed through medical visual technologies, such as endoscopy, and relate it to contemporary discussions on embodiment, embodied vision and bodily presence. The paper concludes with a recent exhibition...

Peripheral Neuropathy, Sensory Processing, and Balance in Survivors of Acute Lymphoblastic Leukemia.

Science.gov (United States)

Varedi, Mitra; Lu, Lu; Howell, Carrie R; Partin, Robyn E; Hudson, Melissa M; Pui, Ching-Hon; Krull, Kevin R; Robison, Leslie L; Ness, Kirsten K; McKenna, Raymond F

2018-05-29

Purpose To compare peripheral nervous system function and balance between adult survivors of childhood acute lymphoblastic leukemia (ALL) and matched controls and to determine associations between peripheral neuropathy (PN) and limitations in static balance, mobility, walking endurance, and quality of life (QoL) among survivors. Patients and Methods Three hundred sixty-five adult survivors of childhood ALL and 365 controls with no cancer history completed assessments of PN (modified Total Neuropathy Score [mTNS]), static balance (Sensory Organization Test [SOT]), mobility (Timed Up and Go), walking endurance (6-minute walk test), QoL (Medical Outcomes Study 36-Item Short Form Survey), and visual-motor processing speed (Wechsler Adult Intelligence Scale). Results PN, but not impairments, in performance on SOT was more common in survivors than controls (41.4% v 9.5%, respectively; P general health). Processing speed (β = 1.69; 95% CI, 0.98 to 2.40; P balance. The association between processing speed and sway suggests that static balance impairment in ALL survivors may be influenced by problems with CNS function, including the processing of sensory information.

The role of visual skills and its impact on skill performance of cricket ...

African Journals Online (AJOL)

The aim of this study was to determine the role and the impact of a visual skills training programme on the skills performance of cricket players, and whether visual training programmes are beneficial to competitive sports performance. Highly skilled cricket players (n=13) who were actively participating at a provincial level of ...

Differential learning and memory performance in OEF/OIF veterans for verbal and visual material.

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Sozda, Christopher N; Muir, James J; Springer, Utaka S; Partovi, Diana; Cole, Michael A

2014-05-01

Memory complaints are particularly salient among veterans who experience combat-related mild traumatic brain injuries and/or trauma exposure, and represent a primary barrier to successful societal reintegration and everyday functioning. Anecdotally within clinical practice, verbal learning and memory performance frequently appears differentially reduced versus visual learning and memory scores. We sought to empirically investigate the robustness of a verbal versus visual learning and memory discrepancy and to explore potential mechanisms for a verbal/visual performance split. Participants consisted of 103 veterans with reported history of mild traumatic brain injuries returning home from U.S. military Operations Enduring Freedom and Iraqi Freedom referred for outpatient neuropsychological evaluation. Findings indicate that visual learning and memory abilities were largely intact while verbal learning and memory performance was significantly reduced in comparison, residing at approximately 1.1 SD below the mean for verbal learning and approximately 1.4 SD below the mean for verbal memory. This difference was not observed in verbal versus visual fluency performance, nor was it associated with estimated premorbid verbal abilities or traumatic brain injury history. In our sample, symptoms of depression, but not posttraumatic stress disorder, were significantly associated with reduced composite verbal learning and memory performance. Verbal learning and memory performance may benefit from targeted treatment of depressive symptomatology. Also, because visual learning and memory functions may remain intact, these might be emphasized when applying neurocognitive rehabilitation interventions to compensate for observed verbal learning and memory difficulties.

Digital Technologies and performative pedagogies: Repositioning the visual

Directory of Open Access Journals (Sweden)

Kathryn Grushka

2010-05-01

Full Text Available Images are becoming a primary means of information presentation in the digitized global media and digital technologies have emancipated and democratized the image. This allows for the reproduction and manipulation of images on a scale never seen before and opens new possibilities for teachers schooled in critical visuality. This paper reports on an innovative pre-service teacher training course in which a cross-curricula cohort of secondary teachers employed visual performative competencies to produce a series of learning objects on a digital platform. The resulting intertextual narratives demonstrate that the manipulation of image and text offered by digital technologies create a powerful vehicle for investigating knowledge and understandings, evolving new meaning and awakening latent creativity in the use of images for meaning making. This research informs the New Literacies and multimodal fields of enquiry and argues that visuality is integral to any pedagogy that purports to be relevant to the contemporary learner. It argues that the visual has been significantly under-valued as a conduit for knowledge acquisition and meaning making in the digital environment and supports the claim that critical literacy, interactivity, experimentation and production are vital to attaining the tenets of transformative education (Buckingham, 2007; Walsh, 2007; Cope & Kalantzis, 2008.

A visual test based on a freeware software for quantifying and displaying night-vision disturbances: study in subjects after alcohol consumption.

Science.gov (United States)

Castro, José J; Ortiz, Carolina; Pozo, Antonio M; Anera, Rosario G; Soler, Margarita

2014-05-07

In this work, we propose the Halo test, a simple visual test based on a freeware software for quantifying and displaying night-vision disturbances perceived by subjects under different experimental conditions, more precisely studying the influence of the alcohol consumption on visual function. In the Halo test, viewed on a monitor, the subject's task consists of detecting luminous peripheral stimuli around a central high-luminance stimulus over a dark background. The test, performed by subjects before and after consuming alcoholic drinks, which deteriorate visual performance, evaluates the influence that alcohol consumption exerts on the visual-discrimination capacity under low illumination conditions. Measurements were made monocularly and binocularly. Pupil size was also measured in both conditions (pre/post). Additionally, we used a double-pass device to measure objectively the optical-quality of the eye and corroborate the results from the Halo test. We found a significant deterioration of the discrimination capacity after alcohol consumption, indicating that the higher the breath-alcohol content, the greater the deterioration of the visual-discrimination capacity. After alcohol intake, the graphical results showed a greater area of undetected peripheral stimuli around the central high-luminance stimulus. An enlargement of the pupil was also observed and the optical quality of the eye was deteriorated after alcohol consumption. A greater influence of halos and other night-vision disturbances were reported with the Halo test after alcohol consumption. The Halo freeware software constitutes a positive contribution for evaluating nighttime visual performance in clinical applications, such as reported here, but also in patients after refractive surgery (where halos are present) or for monitoring (time course) some ocular pathologies under pharmacological treatment.

Integrative Genomics Viewer (IGV): high-performance genomics data visualization and exploration.

Science.gov (United States)

Thorvaldsdóttir, Helga; Robinson, James T; Mesirov, Jill P

2013-03-01

Data visualization is an essential component of genomic data analysis. However, the size and diversity of the data sets produced by today's sequencing and array-based profiling methods present major challenges to visualization tools. The Integrative Genomics Viewer (IGV) is a high-performance viewer that efficiently handles large heterogeneous data sets, while providing a smooth and intuitive user experience at all levels of genome resolution. A key characteristic of IGV is its focus on the integrative nature of genomic studies, with support for both array-based and next-generation sequencing data, and the integration of clinical and phenotypic data. Although IGV is often used to view genomic data from public sources, its primary emphasis is to support researchers who wish to visualize and explore their own data sets or those from colleagues. To that end, IGV supports flexible loading of local and remote data sets, and is optimized to provide high-performance data visualization and exploration on standard desktop systems. IGV is freely available for download from http://www.broadinstitute.org/igv, under a GNU LGPL open-source license.

Development of visual working memory and distractor resistance in relation to academic performance.

Science.gov (United States)

Tsubomi, Hiroyuki; Watanabe, Katsumi

2017-02-01

Visual working memory (VWM) enables active maintenance of goal-relevant visual information in a readily accessible state. The storage capacity of VWM is severely limited, often as few as 3 simple items. Thus, it is crucial to restrict distractor information from consuming VWM capacity. The current study investigated how VWM storage and distractor resistance develop during childhood in relation to academic performance in the classroom. Elementary school children (7- to 12-year-olds) and adults (total N=140) completed a VWM task with and without visual/verbal distractors during the retention period. The results showed that VWM performance with and without distractors developed at similar rates until reaching adult levels at 10years of age. In addition, higher VWM performance without distractors was associated with higher academic scores in literacy (reading and writing), mathematics, and science for the younger children (7- to 9-year-olds), whereas these academic scores for the older children (10- to 12-year-olds) were associated with VWM performance with visual distractors. Taken together, these results suggest that VWM storage and distractor resistance develop at a similar rate, whereas their contributions to academic performance differ with age. Copyright © 2016 Elsevier Inc. All rights reserved.

Long term clinical outcome of peripheral nerve stimulation in patients with chronic peripheral neuropathic pain

DEFF Research Database (Denmark)

Calenbergh, F. Van; Gybels, J.; Laere, K. Van

2009-01-01

BACKGROUND: Chronic neuropathic pain after injury to a peripheral nerve is known to be resistant to treatment. Peripheral nerve stimulation is one of the possible treatment options, which is, however, not performed frequently. In recent years we have witnessed a renewed interest for PNS. The aim...... of the present study was to evaluate the long-term clinical efficacy of PNS in a group of patients with peripheral neuropathic pain treated with PNS since the 1980s. METHODS: Of an original series of 11 patients, 5 patients could be invited for clinical examination, detailed assessment of clinical pain and QST...... functioning) also showed positive effects. Quantitative Sensory Testing results did not show significant differences in cold pain and heat pain thresholds between the "ON" and "OFF" conditions. CONCLUSION: In selected patients with peripheral neuropathic pain PNS remains effective even after more than 20...

A novel approach to 32-channel peripheral nervous system myelin imaging in vivo, with single axon resolution.

Science.gov (United States)

Grochmal, Joey; Teo, Wulin; Gambhir, Hardeep; Kumar, Ranjan; Stratton, Jo Anne; Dhaliwal, Raveena; Brideau, Craig; Biernaskie, Jeff; Stys, Peter K; Midha, Rajiv

2018-01-19

OBJECTIVE Intravital spectral imaging of the large, deeply situated nerves in the rat peripheral nervous system (PNS) has not been well described. Here, the authors have developed a highly stable platform for performing imaging of the tibial nerve in live rodents, thus allowing the capture of high-resolution, high-magnification spectral images requiring long acquisition times. By further exploiting the qualities of the topically applied myelin dye Nile red, this technique is capable of visualizing the detailed microenvironment of peripheral nerve demyelination injury and recovery, while allowing us to obtain images of exogenous Schwann cell myelination in a living animal. METHODS The authors caused doxorubicin-induced focal demyelination in the tibial nerves of 25 Thy-1 GFP rats, of which 2 subsets (n = 10 each) received either BFP-labeled SKP-SCs or SCs to the zone of injury. Prior to acquiring images of myelin recovery in these nerves, a tibial nerve window was constructed using a silicone hemitube, a fast drying silicone polymer, and a small coverslip. This construct was then affixed to a 3D-printed nerve stage, which in turn was affixed to an external fixation/microscope stage device. Myelin visualization was facilitated by the topical application of Nile red. RESULTS The authors reliably demonstrated intravital peripheral nerve myelin imaging with micron-level resolution and magnification, and minimal movement artifact. The detailed microenvironment of nerve remyelination can be vividly observed, while exogenously applied Schwann cells and skin-derived precursor Schwann cells can be seen myelinating axons. CONCLUSIONS Topically applied Nile red enables intravital study of myelin in the living rat PNS. Furthermore, the use of a tibial nerve window facilitates stable intravital peripheral nerve imaging, making possible high-definition spectral imaging with long acquisition times.

Similarity, Not Complexity, Determines Visual Working Memory Performance

Science.gov (United States)

Jackson, Margaret C.; Linden, David E. J.; Roberts, Mark V.; Kriegeskorte, Nikolaus; Haenschel, Corinna

2015-01-01

A number of studies have shown that visual working memory (WM) is poorer for complex versus simple items, traditionally accounted for by higher information load placing greater demands on encoding and storage capacity limits. Other research suggests that it may not be complexity that determines WM performance per se, but rather increased…

Visual performance with sport-tinted contact lenses in natural sunlight.

Science.gov (United States)

Erickson, Graham B; Horn, Fraser C; Barney, Tyler; Pexton, Brett; Baird, Richard Y

2009-05-01

The use of tinted and clear contact lenses (CLs) in all aspects of life is becoming a more popular occurrence, particularly in athletic activities. This study broadens previous research regarding performance-tinted CLs and their effects on measures of visual performance. Thirty-three subjects (14 male, 19 female) were fitted with clear B&L Optima 38, 50% visible light transmission Amber and 36% visible light transmission Gray-Green Nike Maxsight CLs in an individualized randomized sequence. Subjects were dark-adapted with welding goggles before testing and in between subtests involving a Bailey-Lovie chart and the Haynes Distance Rock test. The sequence of testing was repeated for each lens modality. The Amber and Gray-Green lenses enabled subjects to recover vision faster in bright sunlight compared with clear lenses. Also, subjects were able to achieve better visual recognition in bright sunlight when compared with clear lenses. Additionally, the lenses allowed the subjects to alternate fixation between a bright and shaded target at a more rapid rate in bright sunlight as compared with clear lenses. Subjects preferred both the Amber and Gray-Green lenses over clear lenses in the bright and shadowed target conditions. The results of the current study show that Maxsight Amber and Gray-Green lenses provide better contrast discrimination in bright sunlight, better contrast discrimination when alternating between bright and shaded target conditions, better speed of visual recovery in bright sunlight, and better overall visual performance in bright and shaded target conditions compared with clear lenses.

Control of peripheral units by satellite computer

International Nuclear Information System (INIS)

Tran, K.T.

1974-01-01

A computer system was developed allowing the control of nuclear physics experiments, and use of the results by means of graphical and conversational assemblies. This system which is made of two computers, one IBM-370/135 and one Telemecanique Electrique T1600, controls the conventional IBM peripherals and also the special ones made in the laboratory, such as data acquisition display and graphics units. The visual display is implemented by a scanning-type television, equipped with a light-pen. These units in themselves are universal, but their specifications were established to meet the requirements of nuclear physics experiments. The input-output channels of the two computers have been connected together by an interface, designed and implemented in the Laboratory. This interface allows the exchange of control signals and data (the data are changed from bytes into word and vice-versa). The T1600 controls the peripherals mentionned above according to the commands of the IBM370. Hence the T1600 has here the part of a satellite computer which allows conversation with the main computer and also insures the control of its special peripheral units [fr

Effect of a combination of flip and zooming stimuli on the performance of a visual brain-computer interface for spelling.

Science.gov (United States)

Cheng, Jiao; Jin, Jing; Daly, Ian; Zhang, Yu; Wang, Bei; Wang, Xingyu; Cichocki, Andrzej

2018-02-13

Brain-computer interface (BCI) systems can allow their users to communicate with the external world by recognizing intention directly from their brain activity without the assistance of the peripheral motor nervous system. The P300-speller is one of the most widely used visual BCI applications. In previous studies, a flip stimulus (rotating the background area of the character) that was based on apparent motion, suffered from less refractory effects. However, its performance was not improved significantly. In addition, a presentation paradigm that used a "zooming" action (changing the size of the symbol) has been shown to evoke relatively higher P300 amplitudes and obtain a better BCI performance. To extend this method of stimuli presentation within a BCI and, consequently, to improve BCI performance, we present a new paradigm combining both the flip stimulus with a zooming action. This new presentation modality allowed BCI users to focus their attention more easily. We investigated whether such an action could combine the advantages of both types of stimuli presentation to bring a significant improvement in performance compared to the conventional flip stimulus. The experimental results showed that the proposed paradigm could obtain significantly higher classification accuracies and bit rates than the conventional flip paradigm (p<0.01).

(Covert attention and visual speller design in an ERP-based brain-computer interface

Directory of Open Access Journals (Sweden)

Treder Matthias S

2010-05-01

Full Text Available Abstract Background In a visual oddball paradigm, attention to an event usually modulates the event-related potential (ERP. An ERP-based brain-computer interface (BCI exploits this neural mechanism for communication. Hitherto, it was unclear to what extent the accuracy of such a BCI requires eye movements (overt attention or whether it is also feasible for targets in the visual periphery (covert attention. Also unclear was how the visual design of the BCI can be improved to meet peculiarities of peripheral vision such as low spatial acuity and crowding. Method Healthy participants (N = 13 performed a copy-spelling task wherein they had to count target intensifications. EEG and eye movements were recorded concurrently. First, (covert attention was investigated by way of a target fixation condition and a central fixation condition. In the latter, participants had to fixate a dot in the center of the screen and allocate their attention to a target in the visual periphery. Second, the effect of visual speller layout was investigated by comparing the symbol Matrix to an ERP-based Hex-o-Spell, a two-levels speller consisting of six discs arranged on an invisible hexagon. Results We assessed counting errors, ERP amplitudes, and offline classification performance. There is an advantage (i.e., less errors, larger ERP amplitude modulation, better classification of overt attention over covert attention, and there is also an advantage of the Hex-o-Spell over the Matrix. Using overt attention, P1, N1, P2, N2, and P3 components are enhanced by attention. Using covert attention, only N2 and P3 are enhanced for both spellers, and N1 and P2 are modulated when using the Hex-o-Spell but not when using the Matrix. Consequently, classifiers rely mainly on early evoked potentials in overt attention and on later cognitive components in covert attention. Conclusions Both overt and covert attention can be used to drive an ERP-based BCI, but performance is markedly lower

Effect of marihuana and alcohol on visual search performance

Science.gov (United States)

1976-10-01

Two experiments were performed to determine the effects of alcohol and marihuana on visual scanning patterns in a simulated driving situation. In the first experiment 27 male heavy drinkers were divided into 3 groups of 9, defined by three blood alco...

Age and visual impairment decrease driving performance as measured on a closed-road circuit.

Science.gov (United States)

Wood, Joanne M

2002-01-01

In this study the effects of visual impairment and age on driving were investigated and related to visual function. Participants were 139 licensed drivers (young, middle-aged, and older participants with normal vision, and older participants with ocular disease). Driving performance was assessed during the daytime on a closed-road driving circuit. Visual performance was assessed using a vision testing battery. Age and visual impairment had a significant detrimental effect on recognition tasks (detection and recognition of signs and hazards), time to complete driving tasks (overall course time, reversing, and maneuvering), maneuvering ability, divided attention, and an overall driving performance index. All vision measures were significantly affected by group membership. A combination of motion sensitivity, useful field of view (UFOV), Pelli-Robson letter contrast sensitivity, and dynamic acuity could predict 50% of the variance in overall driving scores. These results indicate that older drivers with either normal vision or visual impairment had poorer driving performance compared with younger or middle-aged drivers with normal vision. The inclusion of tests such as motion sensitivity and the UFOV significantly improve the predictive power of vision tests for driving performance. Although such measures may not be practical for widespread screening, their application in selected cases should be considered.

Effect of visual field locus and oscillation frequencies on posture control in an ecological environment.

Science.gov (United States)

Piponnier, Jean-Claude; Hanssens, Jean-Marie; Faubert, Jocelyn

2009-01-14

To examine the respective roles of central and peripheral vision in the control of posture, body sway amplitude (BSA) and postural perturbations (given by velocity root mean square or vRMS) were calculated in a group of 19 healthy young adults. The stimulus was a 3D tunnel, either static or moving sinusoidally in the anterior-posterior direction. There were nine visual field conditions: four central conditions (4, 7, 15, and 30 degrees); four peripheral conditions (central occlusions of 4, 7, 15, and 30 degrees); and a full visual field condition (FF). The virtual tunnel respected all the aspects of a real physical tunnel (i.e., stereoscopy and size increase with proximity). The results show that, under static conditions, central and peripheral visual fields appear to have equal importance for the control of stance. In the presence of an optic flow, peripheral vision plays a crucial role in the control of stance, since it is responsible for a compensatory sway, whereas central vision has an accessory role that seems to be related to spatial orientation.

The effect of visual representation style in problem-solving: a perspective from cognitive processes.

Science.gov (United States)

Nyamsuren, Enkhbold; Taatgen, Niels A

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving.

The Effect of Visual Representation Style in Problem-Solving: A Perspective from Cognitive Processes

Science.gov (United States)

Nyamsuren, Enkhbold; Taatgen, Niels A.

2013-01-01

Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. PMID:24260415

The effect of visual representation style in problem-solving: a perspective from cognitive processes.

Directory of Open Access Journals (Sweden)

Enkhbold Nyamsuren

Full Text Available Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving.

Visual spatial attention enhances the amplitude of positive and negative fMRI responses to visual stimulation in an eccentricity-dependent manner

Science.gov (United States)

Bressler, David W.; Fortenbaugh, Francesca C.; Robertson, Lynn C.; Silver, Michael A.

2013-01-01

Endogenous visual spatial attention improves perception and enhances neural responses to visual stimuli at attended locations. Although many aspects of visual processing differ significantly between central and peripheral vision, little is known regarding the neural substrates of the eccentricity dependence of spatial attention effects. We measured amplitudes of positive and negative fMRI responses to visual stimuli as a function of eccentricity in a large number of topographically-organized cortical areas. Responses to each stimulus were obtained when the stimulus was attended and when spatial attention was directed to a stimulus in the opposite visual hemifield. Attending to the stimulus increased both positive and negative response amplitudes in all cortical areas we studied: V1, V2, V3, hV4, VO1, LO1, LO2, V3A/B, IPS0, TO1, and TO2. However, the eccentricity dependence of these effects differed considerably across cortical areas. In early visual, ventral, and lateral occipital cortex, attentional enhancement of positive responses was greater for central compared to peripheral eccentricities. The opposite pattern was observed in dorsal stream areas IPS0 and putative MT homolog TO1, where attentional enhancement of positive responses was greater in the periphery. Both the magnitude and the eccentricity dependence of attentional modulation of negative fMRI responses closely mirrored that of positive responses across cortical areas. PMID:23562388

Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

International Nuclear Information System (INIS)

Rubel, Oliver; Prabhat, Mr.; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

2008-01-01

Our work combines and extends techniques from high-performance scientific data management and visualization to enable scientific researchers to gain insight from extremely large, complex, time-varying laser wakefield particle accelerator simulation data. We extend histogram-based parallel coordinates for use in visual information display as well as an interface for guiding and performing data mining operations, which are based upon multi-dimensional and temporal thresholding and data subsetting operations. To achieve very high performance on parallel computing platforms, we leverage FastBit, a state-of-the-art index/query technology, to accelerate data mining and multi-dimensional histogram computation. We show how these techniques are used in practice by scientific researchers to identify, visualize and analyze a particle beam in a large, time-varying dataset

Studies of peripheral sensory nerves in paclitaxel-induced painful peripheral neuropathy: Evidence for mitochondrial dysfunction

OpenAIRE

Flatters, Sarah J.L.; Bennett, Gary J.

2006-01-01

Paclitaxel chemotherapy frequently induces neuropathic pain during and often persisting after therapy. The mechanisms responsible for this pain are unknown. Using a rat model of paclitaxel-induced painful peripheral neuropathy, we have performed studies to search for peripheral nerve pathology. Paclitaxel-induced mechano-allodynia and mechano-hyperalgesia were evident after a short delay, peaked at day 27 and finally resolved on day 155. Paclitaxel- and vehicle-treated rats were perfused on d...

Sensory system plasticity in a visually specialized, nocturnal spider.

Science.gov (United States)

Stafstrom, Jay A; Michalik, Peter; Hebets, Eileen A

2017-04-21

The interplay between an animal's environmental niche and its behavior can influence the evolutionary form and function of its sensory systems. While intraspecific variation in sensory systems has been documented across distant taxa, fewer studies have investigated how changes in behavior might relate to plasticity in sensory systems across developmental time. To investigate the relationships among behavior, peripheral sensory structures, and central processing regions in the brain, we take advantage of a dramatic within-species shift of behavior in a nocturnal, net-casting spider (Deinopis spinosa), where males cease visually-mediated foraging upon maturation. We compared eye diameters and brain region volumes across sex and life stage, the latter through micro-computed X-ray tomography. We show that mature males possess altered peripheral visual morphology when compared to their juvenile counterparts, as well as juvenile and mature females. Matching peripheral sensory structure modifications, we uncovered differences in relative investment in both lower-order and higher-order processing regions in the brain responsible for visual processing. Our study provides evidence for sensory system plasticity when individuals dramatically change behavior across life stages, uncovering new avenues of inquiry focusing on altered reliance of specific sensory information when entering a new behavioral niche.

Visual search performance in infants associates with later ASD diagnosis

Directory of Open Access Journals (Sweden)

C.H.M. Cheung

2018-01-01

Full Text Available An enhanced ability to detect visual targets amongst distractors, known as visual search (VS, has often been documented in Autism Spectrum Disorders (ASD. Yet, it is unclear when this behaviour emerges in development and if it is specific to ASD. We followed up infants at high and low familial risk for ASD to investigate how early VS abilities links to later ASD diagnosis, the potential underlying mechanisms of this association and the specificity of superior VS to ASD. Clinical diagnosis of ASD as well as dimensional measures of ASD, attention-deficit/hyperactivity disorder (ADHD and anxiety symptoms were ascertained at 3 years. At 9 and 15 months, but not at age 2 years, high-risk children who later met clinical criteria for ASD (HR-ASD had better VS performance than those without later diagnosis and low-risk controls. Although HR-ASD children were also more attentive to the task at 9 months, this did not explain search performance. Superior VS specifically predicted 3 year-old ASD but not ADHD or anxiety symptoms. Our results demonstrate that atypical perception and core ASD symptoms of social interaction and communication are closely and selectively associated during early development, and suggest causal links between perceptual and social features of ASD. Keywords: Visual search, Visual attention, ASD, ADHD, Infant, Familial risk

Peripheral facial nerve dysfunction: CT evaluation

Energy Technology Data Exchange (ETDEWEB)

Disbro, M.A.; Harnsberger, H.R.; Osborn, A.G.

1985-06-01

Peripheral facial nerve dysfunction may have a clinically apparent or occult cause. The authors reviewed the clinical and radiographic records of 36 patients with peripheral facial nerve dysfunction to obtain information on the location of the suspected lesion and the number, sequence, and type of radiographic evaluations performed. Inadequate clinical evaluations before computed tomography (CT) was done and unnecessary CT examinations were also noted. They have suggested a practical clinical and radiographic scheme to evaluate progressive peripheral facial dysfunction with no apparent cause. If this scheme is applied, unnecessary radiologic tests and delays in diagnosis and treatment may be avoided.

Interaction of hypertension and age in visual selective attention performance.

Science.gov (United States)

Madden, D J; Blumenthal, J A

1998-01-01

Previous research suggests that some aspects of cognitive performance decline as a joint function of age and hypertension. In this experiment, 51 unmedicated individuals with mild essential hypertension and 48 normotensive individuals, 18-78 years of age, performed a visual search task. The estimated time required to identify a display character and shift attention between display positions increased with age. This attention shift time did not differ significantly between hypertensive and normotensive participants, but regression analyses indicated some mediation of the age effect by blood pressure. For individuals less than 60 years of age, the error rate was greater for hypertensive than for normotensive participants. Although the present design could detect effects of only moderate to large size, the results suggest that effects of hypertension may be more evident in a relatively general measure of performance (mean error rate) than in the speed of shifting visual attention.

Homonymous Visual Field Loss and Its Impact on Visual Exploration: A Supermarket Study.

Science.gov (United States)

Kasneci, Enkelejda; Sippel, Katrin; Heister, Martin; Aehling, Katrin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

2014-10-01

Homonymous visual field defects (HVFDs) may critically interfere with quality of life. The aim of this study was to assess the impact of HVFDs on a supermarket search task and to investigate the influence of visual search on task performance. Ten patients with HVFDs (four with a right-sided [HR] and six with a left-sided defect [HL]), and 10 healthy-sighted, sex-, and age-matched control subjects were asked to collect 20 products placed on two supermarket shelves as quickly as possible. Task performance was rated as "passed" or "failed" with regard to the time per correctly collected item ( T C -failed = 4.84 seconds based on the performance of healthy subjects). Eye movements were analyzed regarding the horizontal gaze activity, glance frequency, and glance proportion for different VF areas. Seven of 10 HVFD patients (three HR, four HL) passed the supermarket search task. Patients who passed needed significantly less time per correctly collected item and looked more frequently toward the VFD area than patients who failed. HL patients who passed the test showed a higher percentage of glances beyond the 60° VF ( P < 0.05). A considerable number of HVFD patients performed successfully and could compensate for the HVFD by shifting the gaze toward the peripheral VF and the VFD area. These findings provide new insights on gaze adaptations in patients with HVFDs during activities of daily living and will enhance the design and development of realistic examination tools for use in the clinical setting to improve daily functioning. (http://www.clinicaltrials.gov, NCT01372319, NCT01372332).

Comparative Visual Analysis of Structure-Performance Relations in Complex Bulk-Heterojunction Morphologies

KAUST Repository

Aboulhassan, A.

2017-07-04

The structure of Bulk-Heterojunction (BHJ) materials, the main component of organic photovoltaic solar cells, is very complex, and the relationship between structure and performance is still largely an open question. Overall, there is a wide spectrum of fabrication configurations resulting in different BHJ morphologies and correspondingly different performances. Current state-of-the-art methods for assessing the performance of BHJ morphologies are either based on global quantification of morphological features or simply on visual inspection of the morphology based on experimental imaging. This makes finding optimal BHJ structures very challenging. Moreover, finding the optimal fabrication parameters to get an optimal structure is still an open question. In this paper, we propose a visual analysis framework to help answer these questions through comparative visualization and parameter space exploration for local morphology features. With our approach, we enable scientists to explore multivariate correlations between local features and performance indicators of BHJ morphologies. Our framework is built on shape-based clustering of local cubical regions of the morphology that we call patches. This enables correlating the features of clusters with intuition-based performance indicators computed from geometrical and topological features of charge paths.

Comparative Visual Analysis of Structure-Performance Relations in Complex Bulk-Heterojunction Morphologies

KAUST Repository

Aboulhassan, A.; Sicat, R.; Baum, D.; Wodo, O.; Hadwiger, Markus

2017-01-01

The structure of Bulk-Heterojunction (BHJ) materials, the main component of organic photovoltaic solar cells, is very complex, and the relationship between structure and performance is still largely an open question. Overall, there is a wide spectrum of fabrication configurations resulting in different BHJ morphologies and correspondingly different performances. Current state-of-the-art methods for assessing the performance of BHJ morphologies are either based on global quantification of morphological features or simply on visual inspection of the morphology based on experimental imaging. This makes finding optimal BHJ structures very challenging. Moreover, finding the optimal fabrication parameters to get an optimal structure is still an open question. In this paper, we propose a visual analysis framework to help answer these questions through comparative visualization and parameter space exploration for local morphology features. With our approach, we enable scientists to explore multivariate correlations between local features and performance indicators of BHJ morphologies. Our framework is built on shape-based clustering of local cubical regions of the morphology that we call patches. This enables correlating the features of clusters with intuition-based performance indicators computed from geometrical and topological features of charge paths.

Exploring BOLD changes during spatial attention in non-stimulated visual cortex.

Directory of Open Access Journals (Sweden)

Linda Heinemann

Full Text Available Blood oxygen level-dependent (BOLD responses were measured in parts of primary visual cortex that represented unstimulated visual field regions at different distances from a stimulated central target location. The composition of the visual scene varied by the presence or absence of additional peripheral distracter stimuli. Bottom-up effects were assessed by comparing peripheral activity during central stimulation vs. no stimulation. Top-down effects were assessed by comparing active vs. passive conditions. In passive conditions subjects simply watched the central letter stimuli and in active conditions they had to report occurrence of pre-defined targets in a rapid serial letter stream. Onset of the central letter stream enhanced activity in V1 representations of the stimulated region. Within representations of the periphery activation decreased and finally turned into deactivation with increasing distance from the stimulated location. This pattern was most pronounced in the active conditions and during the presence of peripheral stimuli. Active search for a target did not lead to additional enhancement at areas representing the attentional focus but to a stronger deactivation in the vicinity. Suppressed neuronal activity was also found in the non distracter condition suggesting a top-down attention driven effect. Our observations suggest that BOLD signal decreases in primary visual cortex are modulated by bottom-up sensory-driven factors such as the presence of distracters in the visual field as well as by top-down attentional processes.

Effects of lead on the visual system of occupationally exposed subjects

Energy Technology Data Exchange (ETDEWEB)

Cavalleri, A.; Trimarchi, F.; Gelmi, C.; Baruffini, A.; Minoia, C.; Biscaldi, G.; Gallo, G.

1982-01-01

A quantitative measurement of visual field in mesopic adaptation was performed for 35 workers occupationally exposed to lead and 35 referents matched for age, smoking, and alcohol consumption. The mean level (+/- SD) of lead in blood was 47 +/- 16 microgram/100 ml (2.25 +/- 0.77 mumol/l) (range 21-82 microgram/100 ml (1.01-3.94 mumol/l)). In 10 exposed subjects a central scotoma was found that was not evidenced in any of the referents. A highly significant decrease in visual sensitivity was observed for the exposed subjects a central scotoma was found that was not evidenced in any of the referents. A highly significant decrease in visual sensitivity was observed for the exposed subjects. The results point to damage of central and peripheral optic nerve fibers. In the most severe cases, central vision is preferentially affected, and therefore the results are suggestive of subclinical optic neuropathy.

Spatial Scaling of the Profile of Selective Attention in the Visual Field.

Directory of Open Access Journals (Sweden)

Matthew A Gannon

Full Text Available Neural mechanisms of selective attention must be capable of adapting to variation in the absolute size of an attended stimulus in the ever-changing visual environment. To date, little is known regarding how attentional selection interacts with fluctuations in the spatial expanse of an attended object. Here, we use event-related potentials (ERPs to investigate the scaling of attentional enhancement and suppression across the visual field. We measured ERPs while participants performed a task at fixation that varied in its attentional demands (attentional load and visual angle (1.0° or 2.5°. Observers were presented with a stream of task-relevant stimuli while foveal, parafoveal, and peripheral visual locations were probed by irrelevant distractor stimuli. We found two important effects in the N1 component of visual ERPs. First, N1 modulations to task-relevant stimuli indexed attentional selection of stimuli during the load task and further correlated with task performance. Second, with increased task size, attentional modulation of the N1 to distractor stimuli showed a differential pattern that was consistent with a scaling of attentional selection. Together, these results demonstrate that the size of an attended stimulus scales the profile of attentional selection across the visual field and provides insights into the attentional mechanisms associated with such spatial scaling.

Visualization of Distributed Data Structures for High Performance Fortran-Like Languages

Directory of Open Access Journals (Sweden)

Rainer Koppler

1997-01-01

Full Text Available This article motivates the usage of graphics and visualization for efficient utilization of High Performance Fortran's (HPF's data distribution facilities. It proposes a graphical toolkit consisting of exploratory and estimation tools which allow the programmer to navigate through complex distributions and to obtain graphical ratings with respect to load distribution and communication. The toolkit has been implemented in a mapping design and visualization tool which is coupled with a compilation system for the HPF predecessor Vienna Fortran. Since this language covers a superset of HPF's facilities, the tool may also be used for visualization of HPF data structures.

A human visual model-based approach of the visual attention and performance evaluation

Science.gov (United States)

Le Meur, Olivier; Barba, Dominique; Le Callet, Patrick; Thoreau, Dominique

2005-03-01

In this paper, a coherent computational model of visual selective attention for color pictures is described and its performances are precisely evaluated. The model based on some important behaviours of the human visual system is composed of four parts: visibility, perception, perceptual grouping and saliency map construction. This paper focuses mainly on its performances assessment by achieving extended subjective and objective comparisons with real fixation points captured by an eye-tracking system used by the observers in a task-free viewing mode. From the knowledge of the ground truth, qualitatively and quantitatively comparisons have been made in terms of the measurement of the linear correlation coefficient (CC) and of the Kulback Liebler divergence (KL). On a set of 10 natural color images, the results show that the linear correlation coefficient and the Kullback Leibler divergence are of about 0.71 and 0.46, respectively. CC and Kl measures with this model are respectively improved by about 4% and 7% compared to the best model proposed by L.Itti. Moreover, by comparing the ability of our model to predict eye movements produced by an average observer, we can conclude that our model succeeds quite well in predicting the spatial locations of the most important areas of the image content.

Identification of real-time diagnostic measures of visual distraction with an automatic eye-tracking system.

Science.gov (United States)

Zhang, Harry; Smith, Matthew R H; Witt, Gerald J

2006-01-01

This study was conducted to identify eye glance measures that are diagnostic of visual distraction. Visual distraction degrades performance, but real-time diagnostic measures have not been identified. In a driving simulator, 14 participants responded to a lead vehicle braking at -2 or -2.7 m/s2 periodically while reading a varying number of words (6-15 words every 13 s) on peripheral displays (with diagonal eccentricities of 24 degrees, 43 degrees, and 75 degrees). As the number of words and display eccentricity increased, total glance duration and reaction time increased and driving performance suffered. Correlation coefficients between several glance measures and reaction time or performance variables were reliably high, indicating that these glance measures are diagnostic of visual distraction. It is predicted that for every 25% increase in total glance duration, reaction time is increased by 0.39 s and standard deviation of lane position is increased by 0.06 m. Potential applications of this research include assessing visual distraction in real time, delivering advisories to distracted drivers to reorient their attention to driving, and using distraction information to adapt forward collision and lane departure warning systems to enhance system effectiveness.

(C)overt attention and visual speller design in an ERP-based brain-computer interface.

Science.gov (United States)

Treder, Matthias S; Blankertz, Benjamin

2010-05-28

In a visual oddball paradigm, attention to an event usually modulates the event-related potential (ERP). An ERP-based brain-computer interface (BCI) exploits this neural mechanism for communication. Hitherto, it was unclear to what extent the accuracy of such a BCI requires eye movements (overt attention) or whether it is also feasible for targets in the visual periphery (covert attention). Also unclear was how the visual design of the BCI can be improved to meet peculiarities of peripheral vision such as low spatial acuity and crowding. Healthy participants (N = 13) performed a copy-spelling task wherein they had to count target intensifications. EEG and eye movements were recorded concurrently. First, (c)overt attention was investigated by way of a target fixation condition and a central fixation condition. In the latter, participants had to fixate a dot in the center of the screen and allocate their attention to a target in the visual periphery. Second, the effect of visual speller layout was investigated by comparing the symbol Matrix to an ERP-based Hex-o-Spell, a two-levels speller consisting of six discs arranged on an invisible hexagon. We assessed counting errors, ERP amplitudes, and offline classification performance. There is an advantage (i.e., less errors, larger ERP amplitude modulation, better classification) of overt attention over covert attention, and there is also an advantage of the Hex-o-Spell over the Matrix. Using overt attention, P1, N1, P2, N2, and P3 components are enhanced by attention. Using covert attention, only N2 and P3 are enhanced for both spellers, and N1 and P2 are modulated when using the Hex-o-Spell but not when using the Matrix. Consequently, classifiers rely mainly on early evoked potentials in overt attention and on later cognitive components in covert attention. Both overt and covert attention can be used to drive an ERP-based BCI, but performance is markedly lower for covert attention. The Hex-o-Spell outperforms the

Peripheral retinal nonperfusion associated with chronic myeloid leukemia.

NARCIS (Netherlands)

Nobacht, S.; Vandoninck, K.F.; Deutman, A.F.; Klevering, B.J.

2003-01-01

PURPOSE: To report a case of peripheral retinal nonperfusion and chronic myeloid leukemia in a 23-year-old woman. DESIGN: Observational case report. METHODS: A complete ophthalmic and systemic evaluation was performed. RESULTS: Ophthalmic examination revealed peripheral retinal nonperfusion with

Selective Attention to Visual Stimuli Using Auditory Distractors Is Altered in Alpha-9 Nicotinic Receptor Subunit Knock-Out Mice.

Science.gov (United States)

Terreros, Gonzalo; Jorratt, Pascal; Aedo, Cristian; Elgoyhen, Ana Belén; Delano, Paul H

2016-07-06

During selective attention, subjects voluntarily focus their cognitive resources on a specific stimulus while ignoring others. Top-down filtering of peripheral sensory responses by higher structures of the brain has been proposed as one of the mechanisms responsible for selective attention. A prerequisite to accomplish top-down modulation of the activity of peripheral structures is the presence of corticofugal pathways. The mammalian auditory efferent system is a unique neural network that originates in the auditory cortex and projects to the cochlear receptor through the olivocochlear bundle, and it has been proposed to function as a top-down filter of peripheral auditory responses during attention to cross-modal stimuli. However, to date, there is no conclusive evidence of the involvement of olivocochlear neurons in selective attention paradigms. Here, we trained wild-type and α-9 nicotinic receptor subunit knock-out (KO) mice, which lack cholinergic transmission between medial olivocochlear neurons and outer hair cells, in a two-choice visual discrimination task and studied the behavioral consequences of adding different types of auditory distractors. In addition, we evaluated the effects of contralateral noise on auditory nerve responses as a measure of the individual strength of the olivocochlear reflex. We demonstrate that KO mice have a reduced olivocochlear reflex strength and perform poorly in a visual selective attention paradigm. These results confirm that an intact medial olivocochlear transmission aids in ignoring auditory distraction during selective attention to visual stimuli. The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through the olivocochlear system. It has been proposed to function as a top-down filter of peripheral auditory responses during attention to cross-modal stimuli. However, to date, there is no conclusive evidence of the involvement of olivocochlear

Effects of lighting and task parameters on visual acuity and performance

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Halonen, L.

1993-12-31

Lighting and task parameters and their effects on visual acuity and visual performance are dealt with. The parameters studied are target contrast, target size and subject`s age; and also adaptation luminance, luminance ratio between task and its surrounding and temporal change in luminances are studied. Experiments were carried out to examine the effects of luminance and light spectrum on visual acuity. Young normally sighted, older and low vision people participated in the measurements. In the young and older subject groups the visual acuity remained unchanged at contrasts 0.93 and 0.63 at the luminance range of 15-630 cd/m{sub 2}. The results show that at contrasts 0.03-0.93 young and older subjects` visual acuity remained unchanged in the luminance range of 105-630 cd/m{sub 2}. In the low vision group, the changes in luminances between 25-860 cd/m{sub 2} did not have significant effects on visual acuity measured at high contrast 0.93, at low contrast, slight individual changes were found. The colour temperature of the light sources was altered between 2900-9500 K in the experiment. In the groups of the older, young and low vision subjects the light spectrum did not have significant effects on visual acuity, except for two retinitis pigmentosa subjects. On the basis of the visual acuity experiments, a three dimensional visual acuity model (VA-HUT) has been developed. The model predicts visual acuity as a function of luminance, target contrast and observer age. On the basis of visual acuity experiments visual acuity reserve values have been calculated for different text sizes

Visual bottle inspection performance in highly paced belt-conveyor systems.

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Saito, M; Tanaka, T

1977-12-01

The relation between visual work performance and a few variables with immediate effects, i.e, lighting, work speed, work spell, etc. was studied. At the same time, some physiological and behavioral variations obtained in the study were also discussed. Through experiments and surveys, the optimum conditions were found for each variable. Work performance, however, is affected in such a subtle, interactive and dynamic manner that the working conditions are to be adjusted by taking into account not only these variables having immediate effects but also those indirectly relating ones meeting real needs in the practical working fields. Improvement of some physical working conditions, such as lighting, produces only a transitory increase of performance which is very unstable unless other determinants of performance are simultaneously managed in a proper manner. The same applied to arrangement of the optimum work speed and work spell for highly paced visual inspection, variations in rejection rate and in physiological functions interacting with individual and other determinants. In order to maximize understanding of the integrated and synthesized manner of determinants, it is emphasized that work performance must be pursued in a considerably comprehensive framework from a long-term perspective.

Magnetic resonance angiography of peripheral arteries of the hand and its clinical usefulness

International Nuclear Information System (INIS)

Arikawa, Kouzou

1996-01-01

We established requirements for display of peripheral arteries and veins of the hand on magnetic resonance angiography (MRA) in normal adults. We performed MRA in 20 normal adult volunteers and 3 patients using the same method and parameters and obtained useful clinical examinations. Few studies have evaluated the use of MRA in the hand, especially for peripheral arteries and veins, because of problems of vessel diameter, velocity blood flow, and computer memory capacity. The diagnostic accuracy of MRA is largely dependent on the MR equipment, MR technique, ray-tracing technique, film reading system, and the skill of the MRA film reader. Because MRA methods are not standardized, optimal methods must be determined that produce the accurate information needed for diagnosis of disease. In 20 normal adults, the following MRA parameters allowed us to consistently visualize the peripheral arteries and veins: flip angle, 90deg; TR, 35; TE, 16; slice thickness, 2 mm; FOV, 170; NSA, 2; acquisition matrix, 141 x 256; and room temperature, 22degC. We were able to obtain clear MRA images by the multiple slide slice method, which corrects a weakness of usual methods of display. Results of MRA examinations with our methods and parameters in 20 normal adult volunteers and 3 patients suggest that MRA is safe and useful for clinical examination of the hand. (author)

Effectiveness of Interventions to Address Visual and Visual-Perceptual Impairments to Improve Occupational Performance in Adults With Traumatic Brain Injury: A Systematic Review.

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Berger, Sue; Kaldenberg, Jennifer; Selmane, Romeissa; Carlo, Stephanie

2016-01-01

Visual and visual-perceptual impairments occur frequently with traumatic brain injury (TBI) and influence occupational performance. This systematic review examined the effectiveness of interventions within the scope of occupational therapy to improve occupational performance for adults with visual and visual-perceptual impairments as a result of TBI. Medline, PsycINFO, CINAHL, OTseeker, and the Cochrane Database of Systematic Reviews were searched, and 66 full text articles were reviewed. Sixteen articles were included in the review. Strong evidence supports the use of scanning, limited evidence supports the use of adaptive strategies, and mixed evidence supports the use of cognitive interventions to improve occupational performance for adults with TBI. Evidence related to vision therapy varies on the basis of the specific intervention implemented. Although the strength of the research varied, implications are discussed for practice, education, and research. Copyright © 2016 by the American Occupational Therapy Association, Inc.

Immunohistochemical Analysis in the Rat Central Nervous System and Peripheral Lymph Node Tissue Sections.

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Adzemovic, Milena Z; Zeitelhofer, Manuel; Leisser, Marianne; Köck, Ulricke; Kury, Angela; Olsson, Tomas

2016-11-14

Immunohistochemistry (IHC) provides highly specific, reliable and attractive protein visualization. Correct performance and interpretation of an IHC-based multicolor labeling is challenging, especially when utilized for assessing interrelations between target proteins in the tissue with a high fat content such as the central nervous system (CNS). Our protocol represents a refinement of the standard immunolabeling technique particularly adjusted for detection of both structural and soluble proteins in the rat CNS and peripheral lymph nodes (LN) affected by neuroinflammation. Nonetheless, with or without further modifications, our protocol could likely be used for detection of other related protein targets, even in other organs and species than here presented.

From Big Data to Big Displays High-Performance Visualization at Blue Brain

KAUST Repository

Eilemann, Stefan

2017-10-19

Blue Brain has pushed high-performance visualization (HPV) to complement its HPC strategy since its inception in 2007. In 2011, this strategy has been accelerated to develop innovative visualization solutions through increased funding and strategic partnerships with other research institutions. We present the key elements of this HPV ecosystem, which integrates C++ visualization applications with novel collaborative display systems. We motivate how our strategy of transforming visualization engines into services enables a variety of use cases, not only for the integration with high-fidelity displays, but also to build service oriented architectures, to link into web applications and to provide remote services to Python applications.

Mental practice with interactive 3D visual aids enhances surgical performance.

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Yiasemidou, Marina; Glassman, Daniel; Mushtaq, Faisal; Athanasiou, Christos; Williams, Mark-Mon; Jayne, David; Miskovic, Danilo

2017-10-01

Evidence suggests that Mental Practice (MP) could be used to finesse surgical skills. However, MP is cognitively demanding and may be dependent on the ability of individuals to produce mental images. In this study, we hypothesised that the provision of interactive 3D visual aids during MP could facilitate surgical skill performance. 20 surgical trainees were case-matched to one of three different preparation methods prior to performing a simulated Laparoscopic Cholecystectomy (LC). Two intervention groups underwent a 25-minute MP session; one with interactive 3D visual aids depicting the relevant surgical anatomy (3D-MP group, n = 5) and one without (MP-Only, n = 5). A control group (n = 10) watched a didactic video of a real LC. Scores relating to technical performance and safety were recorded by a surgical simulator. The Control group took longer to complete the procedure relative to the 3D&MP condition (p = .002). The number of movements was also statistically different across groups (p = .001), with the 3D&MP group making fewer movements relative to controls (p = .001). Likewise, the control group moved further in comparison to the 3D&MP condition and the MP-Only condition (p = .004). No reliable differences were observed for safety metrics. These data provide evidence for the potential value of MP in improving performance. Furthermore, they suggest that 3D interactive visual aids during MP could potentially enhance performance, beyond the benefits of MP alone. These findings pave the way for future RCTs on surgical preparation and performance.

Peripheral Contour Grouping and Saccade Targeting: The Role of Mirror Symmetry

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Michaël Sassi

2014-01-01

Full Text Available Integrating shape contours in the visual periphery is vital to our ability to locate objects and thus make targeted saccadic eye movements to efficiently explore our surroundings. We tested whether global shape symmetry facilitates peripheral contour integration and saccade targeting in three experiments, in which observers responded to a successful peripheral contour detection by making a saccade towards the target shape. The target contours were horizontally (Experiment 1 or vertically (Experiments 2 and 3 mirror symmetric. Observers responded by making a horizontal (Experiments 1 and 2 or vertical (Experiment 3 eye movement. Based on an analysis of the saccadic latency and accuracy, we conclude that the figure-ground cue of global mirror symmetry in the periphery has little effect on contour integration or on the speed and precision with which saccades are targeted towards objects. The role of mirror symmetry may be more apparent under natural viewing conditions with multiple objects competing for attention, where symmetric regions in the visual field can pre-attentively signal the presence of objects, and thus attract eye movements.

Performance of LED-based fluorescence microscopy to diagnose tuberculosis in a peripheral health centre in Nairobi.

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Maryline Bonnet

Full Text Available BACKGROUND: Sputum microscopy is the only tuberculosis (TB diagnostic available at peripheral levels of care in resource limited countries. Its sensitivity is low, particularly in high HIV prevalence settings. Fluorescence microscopy (FM can improve performance of microscopy and with the new light emitting diode (LED technologies could be appropriate for peripheral settings. The study aimed to compare the performance of LED-FM versus Ziehl-Neelsen (ZN microscopy and to assess feasibility of LED-FM at a low level of care in a high HIV prevalence country. METHODS: A prospective study was conducted in an urban health clinic in Nairobi, Kenya. Three sputum specimens were collected over 2 days from suspected TB patients. Each sample was processed with Auramine O and ZN methods and a 4(th specimen was collected for TB culture reference standard. Auramine smears were read using the same microscope, equipped with the FluoLED™ fluorescence illuminator. Inter-reader agreement, reading time and technicians' acceptability assessed feasibility. RESULTS: 497 patients were included and 1394 specimens were collected. The detection yields of LED-FM and ZN microscopy were 20.3% and 20.6% (p = 0.64, respectively. Sensitivity was 73.2% for LED-FM and 72% for ZN microscopy, p = 0.32. It was 96.7% and 95.9% for specificity, p = 0.53. Inter-reader agreement was high (kappa = 0.9. Mean reading time was three times faster than ZN microscopy with very good acceptance by technicians. CONCLUSIONS: Although it did not increase sensitivity, the faster reading time combined with very good acceptance and ease of use supports the introduction of LED-FM at the peripheral laboratory level of high TB and HIV burden countries.

Computer-based route-definition system for peripheral bronchoscopy.

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Graham, Michael W; Gibbs, Jason D; Higgins, William E

2012-04-01

Multi-detector computed tomography (MDCT) scanners produce high-resolution images of the chest. Given a patient's MDCT scan, a physician can use an image-guided intervention system to first plan and later perform bronchoscopy to diagnostic sites situated deep in the lung periphery. An accurate definition of complete routes through the airway tree leading to the diagnostic sites, however, is vital for avoiding navigation errors during image-guided bronchoscopy. We present a system for the robust definition of complete airway routes suitable for image-guided bronchoscopy. The system incorporates both automatic and semiautomatic MDCT analysis methods for this purpose. Using an intuitive graphical user interface, the user invokes automatic analysis on a patient's MDCT scan to produce a series of preliminary routes. Next, the user visually inspects each route and quickly corrects the observed route defects using the built-in semiautomatic methods. Application of the system to a human study for the planning and guidance of peripheral bronchoscopy demonstrates the efficacy of the system.

Orienting Attention within Visual Short-Term Memory: Development and Mechanisms

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Shimi, Andria; Nobre, Anna C.; Astle, Duncan; Scerif, Gaia

2014-01-01

How does developing attentional control operate within visual short-term memory (VSTM)? Seven-year-olds, 11-year-olds, and adults (total n = 205) were asked to report whether probe items were part of preceding visual arrays. In Experiment 1, central or peripheral cues oriented attention to the location of to-be-probed items either prior to…

The body voyage as visual representation and art performance.

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Olsén, Jan Eric

2011-01-01

This paper looks at the notion of the body as an interior landscape that is made intelligible through visual representation. It discerns the key figure of the inner corporeal voyage, identifies its main elements and examines how contemporary artists working with performances and installations deal with it. A further aim with the paper is to discuss what kind of image of the body that is conveyed through medical visual technologies, such as endoscopy, and relate it to contemporary discussions on embodiment, embodied vision and bodily presence. The paper concludes with a recent exhibition by the French artist Christian Boltanski, which gives a somewhat different meaning to the idea of the body voyage.

Central as well as peripheral attentional bottlenecks in dual-task performance activate lateral prefrontal cortices

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Andre J Szameitat

2016-03-01

Full Text Available Human information processing suffers from severe limitations in parallel processing. In particular, when required to respond to two stimuli in rapid succession, processing bottlenecks may appear at central and peripheral stages of task processing. Importantly, it has been suggested that executive functions are needed to resolve the interference arising at such bottlenecks. The aims of the present study were to test whether central attentional limitations (i.e., bottleneck at the decisional response selection stage as well as peripheral limitations (i.e., bottleneck at response initiation both demand executive functions located in the lateral prefrontal cortex. For this, we re-analysed two previous studies, in which a total of 33 participants performed a dual-task according to the paradigm of the psychological refractory period (PRP during fMRI. In one study (N=17, the PRP task consisted of two two-choice response tasks known to suffer from a central bottleneck (CB group. In the other study (N=16, the PRP task consisted of two simple-response tasks known to suffer from a peripheral bottleneck (PB group. Both groups showed considerable dual-task costs in form of slowing of the second response in the dual-task (PRP effect. Imaging results are based on the subtraction of both single-tasks from the dual-task within each group. In the CB group, the bilateral middle frontal gyri and inferior frontal gyri were activated. Higher activation in these areas was associated with lower dual-task costs. In the PB group, the right middle frontal and inferior frontal gyrus were activated. Here, higher activation was associated with higher dual-task costs. In conclusion we suggest that central and peripheral bottlenecks both demand executive functions located in lateral prefrontal cortices. Differences between the CB and PB groups with respect to the exact prefrontal areas activated and the correlational patterns suggest that the executive functions resolving

Peripheral epithelial odontogenic tumor

International Nuclear Information System (INIS)

Carzoglio, J.; Tancredi, N.; Capurro, S.; Ravecca, T.; Scarrone, P.

2006-01-01

A new case of peripheral epithelial odontogenic tumor (Pindborg tumor) is reported. It is localized in the superior right gingival region, a less frequent site, and has the histopathological features previously reported. Immunochemical studies were performed, revealing a differential positive stain to cytokeratins in tumor cells deeply seated in the tumor mass, probably related to tumoral cell heterogeneity.Interestingly, in this particular case S-100 protein positive reactivity was also detected in arborescent cells intermingled with tumoral cells, resembling Langerhans cells. Even though referred in the literature in central Pindborg tumors, no references were found about their presence in peripheral tumors, like the one that is presented here

Large-scale network analysis of imagination reveals extended but limited top-down components in human visual cognition.

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Verkhlyutov V.M.

2014-12-01

Full Text Available We investigated whole-brain functional magnetic resonance imaging (fMRI activation in a group of 21 healthy adult subjects during perception, imagination and remembering of two dynamic visual scenarios. Activation of the posterior parts of the cortex prevailed when watching videos. The cognitive tasks of imagination and remembering were accompanied by a predominant activity in the anterior parts of the cortex. An independent component analysis identified seven large-scale cortical networks with relatively invariant spatial distributions across all experimental conditions. The time course of their activation over experimental sessions was task-dependent. These detected networks can be interpreted as a recombination of resting state networks. Both central and peripheral networks were identified within the primary visual cortex. The central network around the caudal pole of BA17 and centers of other visual areas was activated only by direct visual stimulation, while the peripheral network responded to the presentation of visual information as well as to the cognitive tasks of imagination and remembering. The latter result explains the particular susceptibility of peripheral and twilight vision to cognitive top-down influences that often result in false-alarm detections.

[Combination surgery for wet age-related macular degeneration and chronic peripheral uveitis].

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Zapuskalov, I V; Krivosheina, O I; Khoroshikh, Yu I

2016-01-01

To develop a combination surgery for wet age-related macular degeneration and concurrent chronic peripheral uveitis that would include intravitreal injection of Lucentis and cryocerclage of the peripheral retina. A total of 75 patients were examined and divided into 2 groups: the main group (37 patients) and the controls (38 patients). Patients from the main group underwent the new combination surgery, while the controls received intravitreal Lucentis alone (peripheral uveitis was managed therapeutically). It has been found that the new combination method provides a significant and stable improvement in visual acuity (by a factor of 10) and a decrease in the area of central scotoma (by a factor of 2.95) in the postoperative period. The period needed for recovery in the central retinal thickness is also 1.6 times shorter. The new combination surgery for wet age-related macular degeneration and concurrent chronic peripheral uveitis provides rapid reduction of inflammation in the extreme periphery of the fundus and a 1.5 times faster (as compared to traditional methods) primary restoration of topographic anatomy of the retina in the macular region.

The effects of alcohol intoxication on attention and memory for visual scenes.

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Harvey, Alistair J; Kneller, Wendy; Campbell, Alison C

2013-01-01

This study tests the claim that alcohol intoxication narrows the focus of visual attention on to the more salient features of a visual scene. A group of alcohol intoxicated and sober participants had their eye movements recorded as they encoded a photographic image featuring a central event of either high or low salience. All participants then recalled the details of the image the following day when sober. We sought to determine whether the alcohol group would pay less attention to the peripheral features of the encoded scene than their sober counterparts, whether this effect of attentional narrowing was stronger for the high-salience event than for the low-salience event, and whether it would lead to a corresponding deficit in peripheral recall. Alcohol was found to narrow the focus of foveal attention to the central features of both images but did not facilitate recall from this region. It also reduced the overall amount of information accurately recalled from each scene. These findings demonstrate that the concept of alcohol myopia originally posited to explain the social consequences of intoxication (Steele & Josephs, 1990) may be extended to explain the relative neglect of peripheral information during the processing of visual scenes.

Effects of age and auditory and visual dual tasks on closed-road driving performance.

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Chaparro, Alex; Wood, Joanne M; Carberry, Trent

2005-08-01

This study investigated how driving performance of young and old participants is affected by visual and auditory secondary tasks on a closed driving course. Twenty-eight participants comprising two age groups (younger, mean age = 27.3 years; older, mean age = 69.2 years) drove around a 5.1-km closed-road circuit under both single and dual task conditions. Measures of driving performance included detection and identification of road signs, detection and avoidance of large low-contrast road hazards, gap judgment, lane keeping, and time to complete the course. The dual task required participants to verbally report the sums of pairs of single-digit numbers presented through either a computer speaker (auditorily) or a dashboard-mounted monitor (visually) while driving. Participants also completed a vision and cognitive screening battery, including LogMAR visual acuity, Pelli-Robson letter contrast sensitivity, the Trails test, and the Digit Symbol Substitution (DSS) test. Drivers reported significantly fewer signs, hit more road hazards, misjudged more gaps, and increased their time to complete the course under the dual task (visual and auditory) conditions compared with the single task condition. The older participants also reported significantly fewer road signs and drove significantly more slowly than the younger participants, and this was exacerbated for the visual dual task condition. The results of the regression analysis revealed that cognitive aging (measured by the DSS and Trails test) rather than chronologic age was a better predictor of the declines seen in driving performance under dual task conditions. An overall z score was calculated, which took into account both driving and the secondary task (summing) performance under the two dual task conditions. Performance was significantly worse for the auditory dual task compared with the visual dual task, and the older participants performed significantly worse than the young subjects. These findings demonstrate

A longitudinal study of visual function in carriers of X-linked recessive retinitis pigmentosa.

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Grover, S; Fishman, G A; Anderson, R J; Lindeman, M

2000-02-01

This study was carried out to evaluate the progression of visual function impairment in carriers of X-linked recessive retinitis pigmentosa. We also assessed the relationship between the retinal findings at presentation and the extent of deterioration. Observational, retrospective, case series. Twenty-seven carriers of X-linked recessive retinitis pigmentosa. Each carrier was clinically categorized into one of four grades (grades 0 through 3) depending on the presence or absence of a tapetal-like retinal reflex and the extent of peripheral pigmentary degeneration. A complete ophthalmologic examination was performed and data for visual acuity, visual field area, and electroretinographic measurements were collected on the most recent visit in both eyes. These were then compared with similar data obtained on their initial visits. A comparison of visual function was carried out between the initial visit and the most recent visit on each carrier. The visual acuity was measured with Snellen's acuity charts. The visual fields to targets V-4-e and II-4-e were planimeterized and used for the analysis. The electroretinographic (ERG) measures used were light-adapted single-flash b-wave amplitudes and 30-Hz red flicker for cone function, dark-adapted maximal b-wave amplitudes, and response to a low intensity blue-flash for rod function. None of the 11 carriers with a tapetal-like reflex only (grade 1) showed any significant change in visual acuity or fields as compared with 3 of 7 (43%) carriers with diffuse peripheral pigmentary findings (grade 3) who showed significant deterioration in visual acuity in at least one eye, and 6 of 7 (86%) who showed a significant decrease in visual field area with at least one target size in at least one eye. By comparison, only 1 of 10 carriers with a grade 1 fundus finding demonstrated a significant decrease in maximal dark-adapted ERG function as compared with 5 of 6 (83%) carriers with grade 3 in response to a single-flash stimulus and

[Peripheral retinal degenerations--treatment recommendations].

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Joussen, A M; Kirchhof, B

2004-10-01

This report reviews the clinical appearance of degenerative diseases of the peripheral retina in relationship to the risk of developing a rhegmatogenous retinal detachment. We present recommendations for preventive treatment in eyes at increased risk of developing retinal detachment. Retinal degenerations are common lesions involving the peripheral retina but most of them are clinically insignificant. Lattice degeneration, degenerative retinoschisis, cystic retinal tufts, and very rarely zonular traction tufts can result in rhegmatogenous retinal detachment. Therefore, these lesions have been considered for prophylactic treatment; however, adequate studies have not been performed to date. Most of the peripheral retinal degenerations may not require treatment except in rare, high-risk situations. According to current knowledge there is no higher incidence of secondary pucker or other side effects after laser coagulation. Therefore, generous laser indication is recommended if risk factors apply.

Determinants of gross motor skill performance in children with visual impairments.

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Haibach, Pamela S; Wagner, Matthias O; Lieberman, Lauren J

2014-10-01

Children with visual impairments (CWVI) generally perform poorer in gross motor skills when compared with their sighted peers. This study examined the influence of age, sex, and severity of visual impairment upon locomotor and object control skills in CWVI. Participants included 100 CWVI from across the United States who completed the Test of Gross Motor Development II (TGMD-II). The TGMD-II consists of 12 gross motor skills including 6 object control skills (catching, kicking, striking, dribbling, throwing, and rolling) and 6 locomotor skills (running, sliding, galloping, leaping, jumping, and hopping). The full range of visual impairments according to United States Association for Blind Athletes (USABA; B3=20/200-20/599, legally blind; B2=20/600 and up, travel vision; B1=totally blind) were assessed. The B1 group performed significantly worse than the B2 (0.000 ≤ p ≤ 0.049) or B3 groups (0.000 ≤ p ≤ 0.005); however, there were no significant differences between B2 and B3 except for the run (p=0.006), catch (p=0.000), and throw (p=0.012). Age and sex did not play an important role in most of the skills, with the exception of boys outperforming girls striking (p=0.009), dribbling (p=0.013), and throwing (p=0.000), and older children outperforming younger children in dribbling (p=0.002). The significant impact of the severity of visual impairment is likely due to decreased experiences and opportunities for children with more severe visual impairments. In addition, it is likely that these reduced experiences explain the lack of age-related differences in the CWVI. The large disparities in performance between children who are blind and their partially sighted peers give direction for instruction and future research. In addition, there is a critical need for intentional and specific instruction on motor skills at a younger age to enable CWVI to develop their gross motor skills. Copyright © 2014 Elsevier Ltd. All rights reserved.

Visual Attention and Math Performance in Survivors of Childhood Acute Lymphoblastic Leukemia.

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Richard, Annette E; Hodges, Elise K; Heinrich, Kimberley P

2018-01-24

Attentional and academic difficulties, particularly in math, are common in survivors of childhood acute lymphoblastic leukemia (ALL). Of cognitive deficits experienced by survivors of childhood ALL, attention deficits may be particularly responsive to intervention. However, it is unknown whether deficits in particular aspects of attention are associated with deficits in math skills. The current study investigated relationships between math calculation skills, performance on an objective measure of sustained attention, and parent- and teacher-reported attention difficulties. Twenty-four survivors of childhood ALL (Mage = 13.5 years, SD= 2.8 years) completed a computerized measure of sustained attention and response control and a written measure of math calculation skills in the context of a comprehensive clinical neuropsychological evaluation. Parent and teacher ratings of inattention and impulsivity were obtained. Visual response control and visual attention accounted for 26.4% of the variance observed among math performance scores after controlling for IQ (p < .05). Teacher-rated, but not parent-rated, inattention was significantly negatively correlated with math calculation scores. Consistency of responses to visual stimuli on a computerized measure of attention is a unique predictor of variance in math performance among survivors of childhood ALL. Objective testing of visual response control, rather than parent-rated attentional problems, may have clinical utility in identifying ALL survivors at risk for math difficulties. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A concurrent visualization system for large-scale unsteady simulations. Parallel vector performance on an NEC SX-4

International Nuclear Information System (INIS)

Takei, Toshifumi; Doi, Shun; Matsumoto, Hideki; Muramatsu, Kazuhiro

2000-01-01

We have developed a concurrent visualization system RVSLIB (Real-time Visual Simulation Library). This paper shows the effectiveness of the system when it is applied to large-scale unsteady simulations, for which the conventional post-processing approach may no longer work, on high-performance parallel vector supercomputers. The system performs almost all of the visualization tasks on a computation server and uses compressed visualized image data for efficient communication between the server and the user terminal. We have introduced several techniques, including vectorization and parallelization, into the system to minimize the computational costs of the visualization tools. The performance of RVSLIB was evaluated by using an actual CFD code on an NEC SX-4. The computational time increase due to the concurrent visualization was at most 3% for a smaller (1.6 million) grid and less than 1% for a larger (6.2 million) one. (author)

Symmetric visualization of the femoral heads in reticuloendothelial bone marrow scanning in adults

Energy Technology Data Exchange (ETDEWEB)

Munz, D L; Hoer, G

1983-03-01

Two hundred and twenty seven consecutive patients of either sex aged 15-84 suffering from various benign and malignant disorders were studied by sup(99m)Tc-HSA-MM reticuloendothelial bone marrow scintigraphy. In all patients, symmetric findings concerning visualization or nonvisualization of the femoral heads could be seen. Femoral heads were clearly visualized in 48%, nonvisualized in 43%, and equivocally visualized in 9%. In patients with clearly visualized femoral heads, the bone marrow showed peripheral extension in 81%, whereas in patients with nonvisualized femoral heads, bone marrow extension was observed in only 42%. There was a correlation between the degree of bone marrow extension and the ability to visualize femoral heads. There was no obvious difference between males and females, nor patients with various diseases or treatments, amongst nor between different age groups. Two hypotheses are suggested to explain the correspondence between presence of bone marrow tissue in the femoral heads and peripheral extension of the bone marrow organ. Nonvisualization of the femoral heads alone is insufficient to establish the diagnosis of avascular necrosis.

Catheter indwell time and phlebitis development during peripheral intravenous catheter administration.

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Pasalioglu, Kadriye Burcu; Kaya, Hatice

2014-07-01

Intravenous catheters have been indispensable tools of modern medicine. Although intravenous applications can be used for a multitude of purposes, these applications may cause complications, some of which have serious effects. Of these complications, the most commonly observed is phlebitis. This study was conducted to determine the effect of catheter indwell time on phlebitis development during peripheral intravenous catheter administration. This study determined the effect of catheter indwell time on phlebitis development during peripheral intravenous catheter administration. The study included a total of 103 individuals who were administered 439 catheters and satisfied the study enrollment criteria at one infectious diseases clinic in Istanbul/Turkey. Data were compiled from Patient Information Forms, Peripheral Intravenous Catheter and Therapy Information Forms, reported grades based on the Visual Infusion Phlebitis Assessment Scale, and Peripheral Intravenous Catheter Nurse Observation Forms. The data were analyzed using SPSS. Results : The mean patient age was 53.75±15.54 (standard deviation) years, and 59.2% of the study participants were men. Phlebitis was detected in 41.2% of peripheral intravenous catheters, and the rate decreased with increased catheter indwell time. Analyses showed that catheter indwell time, antibiotic usage, sex, and catheterization sites were significantly associated with development of phlebitis. The results of this study show that catheters can be used for longer periods of time when administered under optimal conditions and with appropriate surveillance.

Clinical impact of exercise in patients with peripheral arterial disease.

Science.gov (United States)

Novakovic, Marko; Jug, Borut; Lenasi, Helena

2017-08-01

Increasing prevalence, high morbidity and mortality, and decreased health-related quality of life are hallmarks of peripheral arterial disease. About one-third of peripheral arterial disease patients have intermittent claudication with deleterious effects on everyday activities, such as walking. Exercise training improves peripheral arterial disease symptoms and is recommended as first line therapy for peripheral arterial disease. This review examines the effects of exercise training beyond improvements in walking distance, namely on vascular function, parameters of inflammation, activated hemostasis and oxidative stress, and quality of life. Exercise training not only increases walking distance and physiologic parameters in patients with peripheral arterial disease, but also improves the cardiovascular risk profile by helping patients achieve better control of hypertension, hyperglycemia, obesity and dyslipidemia, thus further reducing cardiovascular risk and the prevalence of coexistent atherosclerotic diseases. American guidelines suggest supervised exercise training, performed for a minimum of 30-45 min, at least three times per week, for at least 12 weeks. Walking is the most studied exercise modality and its efficacy in improving cardiovascular parameters in patients with peripheral arterial disease has been extensively proven. As studies have shown that supervised exercise training improves walking performance, cardiovascular parameters and quality of life in patients with peripheral arterial disease, it should be encouraged and more often prescribed.

Effects of thai foot massage on balance performance in diabetic patients with peripheral neuropathy: a randomized parallel-controlled trial.

Science.gov (United States)

Chatchawan, Uraiwan; Eungpinichpong, Wichai; Plandee, Piyawan; Yamauchi, Junichiro

2015-04-20

BACKGROUND Peripheral neuropathy is the most common complications of diabetic patients and leads to loss of plantar cutaneous sensation, movement perception, and body balance. Thai foot massage is an alternative therapy to improve balance. Therefore, the purpose of this study was to investigate the effects of Thai foot massage on balance performance in diabetic patients with peripheral neuropathy. MATERIAL AND METHODS Sixty patients with type-2 diabetes were recruited and randomly assigned into either the Thai foot massage or control groups. The Thai foot massage group received a modified Thai traditional foot massage for 30 min, 3 days per week for 2 weeks. We measured timed up and go (TUG), one leg stance: OLS), the range of motion (ROM) of the foot, and foot sensation (SWMT) before treatment, after the first single session, and after the 2-week treatment. RESULTS After the single treatment session, only the Thai foot massage group showed a significant improvement in TUG. After the 2-week treatment, both Thai foot massage and control groups showed a significant improvement of TUG and OLS (Pfoot massage group showed better improvement in TUG than the control group (pfoot massage group also showed significant improvements in ROM and SWMT after the 2-week treatment. CONCLUSIONS The results of this study suggest that Thai foot massage is a viable alternative treatment for balance performance, ROM of the foot, and the foot sensation in diabetic patients with peripheral neuropathy.

Bilateral foveal retinoschisis accompanying unilateral peripheral retinoschisis

Directory of Open Access Journals (Sweden)

Nilufer Kocak

2014-01-01

Full Text Available X-linked juvenile retinoschisis is a rare hereditary retinal disease characterized by a tangential splitting of the neurosensory retina which may cause early-onset visual impairment. Existence of the retinal neurosensory layer splitting on cross-sectional images of optical coherance tomography (OCT and the absence of leakage on fluorescein angiography (FA help confirming the diagnosis. Such diagnostic tests are also helpful in determining the management of the disease. However, most of the retinoschisis cavities remain stable and rarely extend to the posterior pole, many authors suggest laser prophylaxis to avoid the potential risk of retinal detachment due to holes in the outer retinal layer. Herein, we report a case with bilateral foveal retinoschisis accompanying unilateral peripheral retinoschisis who was evaluated with detailed ophthalmologic examination. Visual acuity, fundoscopy, OCT, and FA remained stable in the second year of follow-up after prophylactic argon laser treatment.

Perceptual learning improves visual performance in juvenile amblyopia.

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Li, Roger W; Young, Karen G; Hoenig, Pia; Levi, Dennis M

2005-09-01

To determine whether practicing a position-discrimination task improves visual performance in children with amblyopia and to determine the mechanism(s) of improvement. Five children (age range, 7-10 years) with amblyopia practiced a positional acuity task in which they had to judge which of three pairs of lines was misaligned. Positional noise was produced by distributing the individual patches of each line segment according to a Gaussian probability function. Observers were trained at three noise levels (including 0), with each observer performing between 3000 and 4000 responses in 7 to 10 sessions. Trial-by-trial feedback was provided. Four of the five observers showed significant improvement in positional acuity. In those four observers, on average, positional acuity with no noise improved by approximately 32% and with high noise by approximately 26%. A position-averaging model was used to parse the improvement into an increase in efficiency or a decrease in equivalent input noise. Two observers showed increased efficiency (51% and 117% improvements) with no significant change in equivalent input noise across sessions. The other two observers showed both a decrease in equivalent input noise (18% and 29%) and an increase in efficiency (17% and 71%). All five observers showed substantial improvement in Snellen acuity (approximately 26%) after practice. Perceptual learning can improve visual performance in amblyopic children. The improvement can be parsed into two important factors: decreased equivalent input noise and increased efficiency. Perceptual learning techniques may add an effective new method to the armamentarium of amblyopia treatments.

Water soluble peripheral and non-peripheral tetrasubstituted zinc phthalocyanines: Synthesis, photochemistry and bovine serum albumin binding behavior

Energy Technology Data Exchange (ETDEWEB)

Çakır, Volkan; Çakır, Dilek [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Department of Food Technology, Çanakkale Vocational School of Technical Sciences, Çanakkale Onsekiz Mart University, 17100 Çanakkale (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze 41400, Kocaeli (Turkey); Bıyıklıoğlu, Zekeriya, E-mail: zekeriya_61@yahoo.com [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2014-10-15

The new peripherally and non-peripherally tetra-1,3-bis[3-(diethylamino)phenoxy]propan-2-ol substituted zinc(II) phthalocyanine complexes (2a and 3a) and their quaternized amphiphilic derivatives (2b and 3b) have been synthesized and characterized using UV–vis, FT-IR, {sup 1}H-NMR, {sup 13}C-NMR, MS spectroscopic data and elemental analysis for the first time. The quaternized complexes (2b and 3b) show excellent solubility in water and DMSO which makes them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. The photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of these novel phthalocyanines are investigated in dimethylsulfoxide (DMSO) for non-quaternized complexes and in DMSO, phosphate buffered solution (PBS) or PBS+triton X-100 (TX) solution for quaternized complexes. In this study, the effects of the aggregation of the molecules, quaternization, position of the substituents (peripherally or non-peripherally) and nature of the solvents (DMSO, PBS or PBS+triton X-100) on the photochemical parameters of the zinc (II) phthalocyanines are also reported. In addition, a spectroscopic investigation of the binding behavior of the quaternized zinc(II) phthalocyanine complexes to bovine serum albumin (BSA) is also presented in this work. - Highlights: • Synthesis of zinc phthalocyanines is performed. • Photophysical and photochemical properties of phthalocyanines are studied. • Photodynamic therapy studies are performed.

Water soluble peripheral and non-peripheral tetrasubstituted zinc phthalocyanines: Synthesis, photochemistry and bovine serum albumin binding behavior

International Nuclear Information System (INIS)

Çakır, Volkan; Çakır, Dilek; Pişkin, Mehmet; Durmuş, Mahmut; Bıyıklıoğlu, Zekeriya

2014-01-01

The new peripherally and non-peripherally tetra-1,3-bis[3-(diethylamino)phenoxy]propan-2-ol substituted zinc(II) phthalocyanine complexes (2a and 3a) and their quaternized amphiphilic derivatives (2b and 3b) have been synthesized and characterized using UV–vis, FT-IR, 1 H-NMR, 13 C-NMR, MS spectroscopic data and elemental analysis for the first time. The quaternized complexes (2b and 3b) show excellent solubility in water and DMSO which makes them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. The photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of these novel phthalocyanines are investigated in dimethylsulfoxide (DMSO) for non-quaternized complexes and in DMSO, phosphate buffered solution (PBS) or PBS+triton X-100 (TX) solution for quaternized complexes. In this study, the effects of the aggregation of the molecules, quaternization, position of the substituents (peripherally or non-peripherally) and nature of the solvents (DMSO, PBS or PBS+triton X-100) on the photochemical parameters of the zinc (II) phthalocyanines are also reported. In addition, a spectroscopic investigation of the binding behavior of the quaternized zinc(II) phthalocyanine complexes to bovine serum albumin (BSA) is also presented in this work. - Highlights: • Synthesis of zinc phthalocyanines is performed. • Photophysical and photochemical properties of phthalocyanines are studied. • Photodynamic therapy studies are performed

Common constraints limit Korean and English character recognition in peripheral vision.

Science.gov (United States)

He, Yingchen; Kwon, MiYoung; Legge, Gordon E

2018-01-01

The visual span refers to the number of adjacent characters that can be recognized in a single glance. It is viewed as a sensory bottleneck in reading for both normal and clinical populations. In peripheral vision, the visual span for English characters can be enlarged after training with a letter-recognition task. Here, we examined the transfer of training from Korean to English characters for a group of bilingual Korean native speakers. In the pre- and posttests, we measured visual spans for Korean characters and English letters. Training (1.5 hours × 4 days) consisted of repetitive visual-span measurements for Korean trigrams (strings of three characters). Our training enlarged the visual spans for Korean single characters and trigrams, and the benefit transferred to untrained English symbols. The improvement was largely due to a reduction of within-character and between-character crowding in Korean recognition, as well as between-letter crowding in English recognition. We also found a negative correlation between the size of the visual span and the average pattern complexity of the symbol set. Together, our results showed that the visual span is limited by common sensory (crowding) and physical (pattern complexity) factors regardless of the language script, providing evidence that the visual span reflects a universal bottleneck for text recognition.

Individual personality differences in goats predict their performance in visual learning and non-associative cognitive tasks.

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Nawroth, Christian; Prentice, Pamela M; McElligott, Alan G

2017-01-01

Variation in common personality traits, such as boldness or exploration, is often associated with risk-reward trade-offs and behavioural flexibility. To date, only a few studies have examined the effects of consistent behavioural traits on both learning and cognition. We investigated whether certain personality traits ('exploration' and 'sociability') of individuals were related to cognitive performance, learning flexibility and learning style in a social ungulate species, the goat (Capra hircus). We also investigated whether a preference for feature cues rather than impaired learning abilities can explain performance variation in a visual discrimination task. We found that personality scores were consistent across time and context. Less explorative goats performed better in a non-associative cognitive task, in which subjects had to follow the trajectory of a hidden object (i.e. testing their ability for object permanence). We also found that less sociable subjects performed better compared to more sociable goats in a visual discrimination task. Good visual learning performance was associated with a preference for feature cues, indicating personality-dependent learning strategies in goats. Our results suggest that personality traits predict the outcome in visual discrimination and non-associative cognitive tasks in goats and that impaired performance in a visual discrimination tasks does not necessarily imply impaired learning capacities, but rather can be explained by a varying preference for feature cues. Copyright © 2016 Elsevier B.V. All rights reserved.

Competition between auditory and visual spatial cues during visual task performance

NARCIS (Netherlands)

Koelewijn, T.; Bronkhorst, A.; Theeuwes, J.

2009-01-01

There is debate in the crossmodal cueing literature as to whether capture of visual attention by means of sound is a fully automatic process. Recent studies show that when visual attention is endogenously focused sound still captures attention. The current study investigated whether there is

High performance geospatial and climate data visualization using GeoJS

Science.gov (United States)

Chaudhary, A.; Beezley, J. D.

2015-12-01

GeoJS (https://github.com/OpenGeoscience/geojs) is an open-source library developed to support interactive scientific and geospatial visualization of climate and earth science datasets in a web environment. GeoJS has a convenient application programming interface (API) that enables users to harness the fast performance of WebGL and Canvas 2D APIs with sophisticated Scalable Vector Graphics (SVG) features in a consistent and convenient manner. We started the project in response to the need for an open-source JavaScript library that can combine traditional geographic information systems (GIS) and scientific visualization on the web. Many libraries, some of which are open source, support mapping or other GIS capabilities, but lack the features required to visualize scientific and other geospatial datasets. For instance, such libraries are not be capable of rendering climate plots from NetCDF files, and some libraries are limited in regards to geoinformatics (infovis in a geospatial environment). While libraries such as d3.js are extremely powerful for these kinds of plots, in order to integrate them into other GIS libraries, the construction of geoinformatics visualizations must be completed manually and separately, or the code must somehow be mixed in an unintuitive way.We developed GeoJS with the following motivations:• To create an open-source geovisualization and GIS library that combines scientific visualization with GIS and informatics• To develop an extensible library that can combine data from multiple sources and render them using multiple backends• To build a library that works well with existing scientific visualizations tools such as VTKWe have successfully deployed GeoJS-based applications for multiple domains across various projects. The ClimatePipes project funded by the Department of Energy, for example, used GeoJS to visualize NetCDF datasets from climate data archives. Other projects built visualizations using GeoJS for interactively exploring

The Charles F. Prentice Award Lecture 2010: A Case for Peripheral Optical Treatment Strategies for Myopia

Science.gov (United States)

Smith, Earl L.

2011-01-01

It is well established that refractive development is regulated by visual feedback. However, most optical treatment strategies designed to reduce myopia progression have not produced the desired results, primarily because some of our assumptions concerning the operating characteristics of the vision-dependent mechanisms that regulate refractive development have been incorrect. In particular, because of the prominence of central vision in primates, it has generally been assumed that signals from the fovea determine the effects of vision on refractive development. However, experiments in laboratory animals demonstrate that ocular growth and emmetropization are mediated by local retinal mechanisms and that foveal vision is not essential for many vision-dependent aspects of refractive development. On the other hand, the peripheral retina, in isolation, can effectively regulate emmetropization and mediate many of the effects of vision on the eye’s refractive status. Moreover, when there are conflicting visual signals between the fovea and the periphery, peripheral vision can dominate refractive development. The overall pattern of results suggests that optical treatment strategies for myopia that take into account the effects of peripheral vision are likely to be more successful than strategies that effectively manipulate only central vision. PMID:21747306

Improving Mobility Performance in Low Vision With a Distance-Based Representation of the Visual Scene.

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van Rheede, Joram J; Wilson, Iain R; Qian, Rose I; Downes, Susan M; Kennard, Christopher; Hicks, Stephen L

2015-07-01

Severe visual impairment can have a profound impact on personal independence through its effect on mobility. We investigated whether the mobility of people with vision low enough to be registered as blind could be improved by presenting the visual environment in a distance-based manner for easier detection of obstacles. We accomplished this by developing a pair of "residual vision glasses" (RVGs) that use a head-mounted depth camera and displays to present information about the distance of obstacles to the wearer as brightness, such that obstacles closer to the wearer are represented more brightly. We assessed the impact of the RVGs on the mobility performance of visually impaired participants during the completion of a set of obstacle courses. Participant position was monitored continuously, which enabled us to capture the temporal dynamics of mobility performance. This allowed us to find correlates of obstacle detection and hesitations in walking behavior, in addition to the more commonly used measures of trial completion time and number of collisions. All participants were able to use the smart glasses to navigate the course, and mobility performance improved for those visually impaired participants with the worst prior mobility performance. However, walking speed was slower and hesitations increased with the altered visual representation. A depth-based representation of the visual environment may offer low vision patients improvements in independent mobility. It is important for further work to explore whether practice can overcome the reductions in speed and increased hesitation that were observed in our trial.

Peripheral, functional and postural asymmetries related to the preferred chewing side in adults with natural dentition.

Science.gov (United States)

Rovira-Lastra, B; Flores-Orozco, E I; Ayuso-Montero, R; Peraire, M; Martinez-Gomis, J

2016-04-01

The aim of this cross-sectional study was to determine the preferred chewing side and whether chewing side preference is related to peripheral, functional or postural lateral preferences. One hundred and forty-six adults with natural dentition performed three masticatory assays, each consisting of five trials of chewing three pieces of silicon placed into a latex bag for 20 cycles, either freestyle or unilaterally on the right- or left-hand side. Occlusal contact area in the intercuspal position, maximum bite force, masticatory performance and cycle duration were measured and the lateral asymmetry of these variables was calculated. Laterality tests were performed to determine handedness, footedness, earedness and eyedness as functional preferences, and hand-clasping, arm-folding and leg-crossing as postural lateral preferences. The preferred chewing side was determined using three different methods: assessment of the first chewing cycle for each trial, calculation of the asymmetry index from all cycles and application of a visual analogue scale. Bivariate relationship and multiple linear regression analyses were performed. Among unilateral chewers, 77% of them preferred the right side for chewing. The factors most closely related to the preferred chewing side were asymmetry of bite force, asymmetry of masticatory performance and earedness, which explained up to 16% of the variance. Although several functional or postural lateral preferences seem to be related to the preferred chewing side, peripheral factors such as asymmetry of bite force and of masticatory performance are the most closely related to the preferred chewing side in adults with natural dentition. © 2015 John Wiley & Sons Ltd.

The influence of anaesthetists' experience on workload, performance and visual attention during simulated critical incidents.

Science.gov (United States)

Schulz, Christian M; Schneider, Erich; Kohlbecher, Stefan; Hapfelmeier, Alexander; Heuser, Fabian; Wagner, Klaus J; Kochs, Eberhard F; Schneider, Gerhard

2014-10-01

Development of accurate Situation Awareness (SA) depends on experience and may be impaired during excessive workload. In order to gain adequate SA for decision making and performance, anaesthetists need to distribute visual attention effectively. Therefore, we hypothesized that in more experienced anaesthetists performance is better and increase of physiological workload is less during critical incidents. Additionally, we investigated the relation between physiological workload indicators and distribution of visual attention. In fifteen anaesthetists, the increase of pupil size and heart rate was assessed in course of a simulated critical incident. Simulator log files were used for performance assessment. An eye-tracking device (EyeSeeCam) provided data about the anaesthetists' distribution of visual attention. Performance was assessed as time until definitive treatment. T tests and multivariate generalized linear models (MANOVA) were used for retrospective statistical analysis. Mean pupil diameter increase was 8.1% (SD ± 4.3) in the less experienced and 15.8% (±10.4) in the more experienced subjects (p = 0.191). Mean heart rate increase was 10.2% (±6.7) and 10.5% (±8.3, p = 0.956), respectively. Performance did not depend on experience. Pupil diameter and heart rate increases were associated with a shift of visual attention from monitoring towards manual tasks (not significant). For the first time, the following four variables were assessed simultaneously: physiological workload indicators, performance, experience, and distribution of visual attention between "monitoring" and "manual" tasks. However, we were unable to detect significant interactions between these variables. This experimental model could prove valuable in the investigation of gaining and maintaining SA in the operation theatre.

Theta coupling between V4 and prefrontal cortex predicts visual short-term memory performance.

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Liebe, Stefanie; Hoerzer, Gregor M; Logothetis, Nikos K; Rainer, Gregor

2012-01-29

Short-term memory requires communication between multiple brain regions that collectively mediate the encoding and maintenance of sensory information. It has been suggested that oscillatory synchronization underlies intercortical communication. Yet, whether and how distant cortical areas cooperate during visual memory remains elusive. We examined neural interactions between visual area V4 and the lateral prefrontal cortex using simultaneous local field potential (LFP) recordings and single-unit activity (SUA) in monkeys performing a visual short-term memory task. During the memory period, we observed enhanced between-area phase synchronization in theta frequencies (3-9 Hz) of LFPs together with elevated phase locking of SUA to theta oscillations across regions. In addition, we found that the strength of intercortical locking was predictive of the animals' behavioral performance. This suggests that theta-band synchronization coordinates action potential communication between V4 and prefrontal cortex that may contribute to the maintenance of visual short-term memories.

Mapping Disciplinary Values and Rhetorical Concerns through Language: Writing Instruction in the Performing and Visual Arts

Science.gov (United States)

Cox, Anicca

2015-01-01

Via interview data focused on instructor practices and values, this study sought to describe some of what performing and visual arts instructors do at the university level to effectively teach disciplinary values through writing. The study's research goals explored how relationships to writing process in visual and performing arts support…

Reverse alignment "mirror image" visualization as a laparoscopic training tool improves task performance.

Science.gov (United States)

Dunnican, Ward J; Singh, T Paul; Ata, Ashar; Bendana, Emma E; Conlee, Thomas D; Dolce, Charles J; Ramakrishnan, Rakesh

2010-06-01

Reverse alignment (mirror image) visualization is a disconcerting situation occasionally faced during laparoscopic operations. This occurs when the camera faces back at the surgeon in the opposite direction from which the surgeon's body and instruments are facing. Most surgeons will attempt to optimize trocar and camera placement to avoid this situation. The authors' objective was to determine whether the intentional use of reverse alignment visualization during laparoscopic training would improve performance. A standard box trainer was configured for reverse alignment, and 34 medical students and junior surgical residents were randomized to train with either forward alignment (DIRECT) or reverse alignment (MIRROR) visualization. Enrollees were tested on both modalities before and after a 4-week structured training program specific to their modality. Student's t test was used to determine differences in task performance between the 2 groups. Twenty-one participants completed the study (10 DIRECT, 11 MIRROR). There were no significant differences in performance time between DIRECT or MIRROR participants during forward or reverse alignment initial testing. At final testing, DIRECT participants had improved times only in forward alignment performance; they demonstrated no significant improvement in reverse alignment performance. MIRROR participants had significant time improvement in both forward and reverse alignment performance at final testing. Reverse alignment imaging for laparoscopic training improves task performance for both reverse alignment and forward alignment tasks. This may be translated into improved performance in the operating room when faced with reverse alignment situations. Minimal lab training can account for drastic adaptation to this environment.

Diabetes and obesity are the main metabolic drivers of peripheral neuropathy.

Science.gov (United States)

Callaghan, Brian C; Gao, LeiLi; Li, Yufeng; Zhou, Xianghai; Reynolds, Evan; Banerjee, Mousumi; Pop-Busui, Rodica; Feldman, Eva L; Ji, Linong

2018-04-01

To determine the associations between individual metabolic syndrome (MetS) components and peripheral neuropathy in a large population-based cohort from Pinggu, China. A cross-sectional, randomly selected, population-based survey of participants from Pinggu, China was performed. Metabolic phenotyping and neuropathy outcomes were performed by trained personnel. Glycemic status was defined according to the American Diabetes Association criteria, and the MetS using modified consensus criteria (body mass index instead of waist circumference). The primary peripheral neuropathy outcome was the Michigan Neuropathy Screening Instrument (MNSI) examination. Secondary outcomes were the MNSI questionnaire and monofilament testing. Multivariable models were used to assess for associations between individual MetS components and peripheral neuropathy. Tree-based methods were used to construct a classifier for peripheral neuropathy using demographics and MetS components. The mean (SD) age of the 4002 participants was 51.6 (11.8) and 51.0% were male; 37.2% of the population had normoglycemia, 44.0% prediabetes, and 18.9% diabetes. The prevalence of peripheral neuropathy increased with worsening glycemic status (3.25% in normoglycemia, 6.29% in prediabetes, and 15.12% in diabetes, P peripheral neuropathy. Age, diabetes, and weight were the primary splitters in the classification tree for peripheral neuropathy. Similar to previous studies, diabetes and obesity are the main metabolic drivers of peripheral neuropathy. The consistency of these results reinforces the urgent need for effective interventions that target these metabolic factors to prevent and/or treat peripheral neuropathy.

Visual Outcome after Laser Photocoagulation for Stage 4 ...

African Journals Online (AJOL)

Objective: The objectives of this research is to evaluate the visual outcome after peripheral laser photo-coagulation for Goldberg stage-4 proliferative sickle cell retinopathy patients seen in Eye Foundation Hospital Lagos between January and December 2002. Methodology: A hospital-based retrospective case review study ...

Adaptive Gaze Strategies for Locomotion with Constricted Visual Field

Directory of Open Access Journals (Sweden)

Colas N. Authié

2017-07-01

Full Text Available In retinitis pigmentosa (RP, loss of peripheral visual field accounts for most difficulties encountered in visuo-motor coordination during locomotion. The purpose of this study was to accurately assess the impact of peripheral visual field loss on gaze strategies during locomotion, and identify compensatory mechanisms. Nine RP subjects presenting a central visual field limited to 10–25° in diameter, and nine healthy subjects were asked to walk in one of three directions—straight ahead to a visual target, leftward and rightward through a door frame, with or without obstacle on the way. Whole body kinematics were recorded by motion capture, and gaze direction in space was reconstructed using an eye-tracker. Changes in gaze strategies were identified in RP subjects, including extensive exploration prior to walking, frequent fixations of the ground (even knowing no obstacle was present, of door edges, essentially of the proximal one, of obstacle edge/corner, and alternating door edges fixations when approaching the door. This was associated with more frequent, sometimes larger rapid-eye-movements, larger movements, and forward tilting of the head. Despite the visual handicap, the trajectory geometry was identical between groups, with a small decrease in walking speed in RPs. These findings identify the adaptive changes in sensory-motor coordination, in order to ensure visual awareness of the surrounding, detect changes in spatial configuration, collect information for self-motion, update the postural reference frame, and update egocentric distances to environmental objects. They are of crucial importance for the design of optimized rehabilitation procedures.

Adaptive Gaze Strategies for Locomotion with Constricted Visual Field

Science.gov (United States)

Authié, Colas N.; Berthoz, Alain; Sahel, José-Alain; Safran, Avinoam B.

2017-01-01

In retinitis pigmentosa (RP), loss of peripheral visual field accounts for most difficulties encountered in visuo-motor coordination during locomotion. The purpose of this study was to accurately assess the impact of peripheral visual field loss on gaze strategies during locomotion, and identify compensatory mechanisms. Nine RP subjects presenting a central visual field limited to 10–25° in diameter, and nine healthy subjects were asked to walk in one of three directions—straight ahead to a visual target, leftward and rightward through a door frame, with or without obstacle on the way. Whole body kinematics were recorded by motion capture, and gaze direction in space was reconstructed using an eye-tracker. Changes in gaze strategies were identified in RP subjects, including extensive exploration prior to walking, frequent fixations of the ground (even knowing no obstacle was present), of door edges, essentially of the proximal one, of obstacle edge/corner, and alternating door edges fixations when approaching the door. This was associated with more frequent, sometimes larger rapid-eye-movements, larger movements, and forward tilting of the head. Despite the visual handicap, the trajectory geometry was identical between groups, with a small decrease in walking speed in RPs. These findings identify the adaptive changes in sensory-motor coordination, in order to ensure visual awareness of the surrounding, detect changes in spatial configuration, collect information for self-motion, update the postural reference frame, and update egocentric distances to environmental objects. They are of crucial importance for the design of optimized rehabilitation procedures. PMID:28798674

VISUAL OUTCOME FOLLOWING PANRETINAL PHOTOCOAGULATION IN PROLIFERATIVE DIABETIC RETINOPATHY

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Nellaye Mani Sindhu

2018-01-01

Full Text Available BACKGROUND Diabetes mellitus can be called as a noninfectious pandemic and the incidence of diabetic retinopathy is also uncontrollable. This vision-threatening complication can be treated by early diagnosis and effective treatment like panretinal photocoagulation. The aim of the study is to evaluate the effect of panretinal photocoagulation on visual acuity, colour vision, contrast sensitivity and severity of visual field changes. MATERIALS AND METHODS Prospective study of visual outcome following panretinal photocoagulation in patients with proliferative diabetic retinopathy conducted in Retina Clinic, RIO, Trivandrum, during the time period one year from April 2008. Inclusion Criteria- Eyes with proliferative diabetic retinopathy, visual acuity better than or equal to 6/60, a follow up of at least 6 months after panretinal photocoagulation. Exclusion Criteria- Eyes with cataractous changes in the lens, eyes, which would be undergoing or have undergone focal photocoagulation eyes, which undergone barrage or sectoral retinal photocoagulation, patients with colour blindness, eyes with vitreous haemorrhage and macular preretinal haemorrhage, glaucomatous patients with peripheral field loss. RESULTS The mean age of the patients was 52 years. Male patients (30 outnumbered the female patients (23. Mean duration of diabetes was 14.42 years. Though, there is a statistically significant reduction in visual acuity in the first followup, which was improved and stabilised by 6 months. There is a statistically significant reduction in the contrast sensitivity, which was stabilised after 3 months. Only, 9.5% patients had peripheral constrictions of visual field and no significant change in the colour vision. CONCLUSION We recommend panretinal photocoagulation for all patients with proliferative diabetic retinopathy.

Visualizing request-flow comparison to aid performance diagnosis in distributed systems.

Science.gov (United States)

Sambasivan, Raja R; Shafer, Ilari; Mazurek, Michelle L; Ganger, Gregory R

2013-12-01

Distributed systems are complex to develop and administer, and performance problem diagnosis is particularly challenging. When performance degrades, the problem might be in any of the system's many components or could be a result of poor interactions among them. Recent research efforts have created tools that automatically localize the problem to a small number of potential culprits, but research is needed to understand what visualization techniques work best for helping distributed systems developers understand and explore their results. This paper compares the relative merits of three well-known visualization approaches (side-by-side, diff, and animation) in the context of presenting the results of one proven automated localization technique called request-flow comparison. Via a 26-person user study, which included real distributed systems developers, we identify the unique benefits that each approach provides for different problem types and usage modes.

Application of individually performed titanium mesh in infraorbital wall fracture reconstruction

Directory of Open Access Journals (Sweden)

Kai-Jian Sun

2016-04-01

Full Text Available AIM:To discuss the application effect of individually performed titanium mesh in infraorbital wall fracture reconstruction. METHODS:Sixty-seven patients(67 eyesdiagnosed as infraorbital fracture from January 2011 to February 2014 were performed reconstruction with individually performed titanium mesh. The recovery of incision, visual acuity, eyeball mobility, diplopia and proptosis were monitored by post-operation follow-up which lasted for 1a. RESULTS:No infection, titanium mesh transposition, prolapse, deformities, exclusion or ectropion were occurred in the follow-up period. The eyeball embole was less than 2mm by bilateral proptosis contrast. The diplopia in 5 eyes were disappeared in 4 and approved in one. The eyeball descent in 2 cases was disappeared. The visual acuity was the same compared with pre-operation. The rate of disappeared diplopia at primary position was 93% and improved significantly in the other 3 patients. The rate of disappeared diplopia at peripheral visual field was 86% and improved significantly in the other 2 patients.CONCLUSION:The reconstruction effect of individually performed titanium mesh in infraorbital wall fracture was satisfied and safe.

Enhancing performance expectancies through visual illusions facilitates motor learning in children.

Science.gov (United States)

Bahmani, Moslem; Wulf, Gabriele; Ghadiri, Farhad; Karimi, Saeed; Lewthwaite, Rebecca

2017-10-01

In a recent study by Chauvel, Wulf, and Maquestiaux (2015), golf putting performance was found to be affected by the Ebbinghaus illusion. Specifically, adult participants demonstrated more effective learning when they practiced with a hole that was surrounded by small circles, making it look larger, than when the hole was surrounded by large circles, making it look smaller. The present study examined whether this learning advantage would generalize to children who are assumed to be less sensitive to the visual illusion. Two groups of 10-year olds practiced putting golf balls from a distance of 2m, with perceived larger or smaller holes resulting from the visual illusion. Self-efficacy was increased in the group with the perceived larger hole. The latter group also demonstrated more accurate putting performance during practice. Importantly, learning (i.e., delayed retention performance without the illusion) was enhanced in the group that practiced with the perceived larger hole. The findings replicate previous results with adult learners and are in line with the notion that enhanced performance expectancies are key to optimal motor learning (Wulf & Lewthwaite, 2016). Copyright © 2017 Elsevier B.V. All rights reserved.

Transitions between central and peripheral vision create spatial/temporal distortions: a hypothesis concerning the perceived break of the curveball.

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Arthur Shapiro

2010-10-01

Full Text Available The human visual system does not treat all parts of an image equally: the central segments of an image, which fall on the fovea, are processed with a higher resolution than the segments that fall in the visual periphery. Even though the differences between foveal and peripheral resolution are large, these differences do not usually disrupt our perception of seamless visual space. Here we examine a motion stimulus in which the shift from foveal to peripheral viewing creates a dramatic spatial/temporal discontinuity.The stimulus consists of a descending disk (global motion with an internal moving grating (local motion. When observers view the disk centrally, they perceive both global and local motion (i.e., observers see the disk's vertical descent and the internal spinning. When observers view the disk peripherally, the internal portion appears stationary, and the disk appears to descend at an angle. The angle of perceived descent increases as the observer views the stimulus from further in the periphery. We examine the first- and second-order information content in the display with the use of a three-dimensional Fourier analysis and show how our results can be used to describe perceived spatial/temporal discontinuities in real-world situations.The perceived shift of the disk's direction in the periphery is consistent with a model in which foveal processing separates first- and second-order motion information while peripheral processing integrates first- and second-order motion information. We argue that the perceived distortion may influence real-world visual observations. To this end, we present a hypothesis and analysis of the perception of the curveball and rising fastball in the sport of baseball. The curveball is a physically measurable phenomenon: the imbalance of forces created by the ball's spin causes the ball to deviate from a straight line and to follow a smooth parabolic path. However, the curveball is also a perceptual puzzle

Transitions between central and peripheral vision create spatial/temporal distortions: a hypothesis concerning the perceived break of the curveball.

Science.gov (United States)

Shapiro, Arthur; Lu, Zhong-Lin; Huang, Chang-Bing; Knight, Emily; Ennis, Robert

2010-10-13

The human visual system does not treat all parts of an image equally: the central segments of an image, which fall on the fovea, are processed with a higher resolution than the segments that fall in the visual periphery. Even though the differences between foveal and peripheral resolution are large, these differences do not usually disrupt our perception of seamless visual space. Here we examine a motion stimulus in which the shift from foveal to peripheral viewing creates a dramatic spatial/temporal discontinuity. The stimulus consists of a descending disk (global motion) with an internal moving grating (local motion). When observers view the disk centrally, they perceive both global and local motion (i.e., observers see the disk's vertical descent and the internal spinning). When observers view the disk peripherally, the internal portion appears stationary, and the disk appears to descend at an angle. The angle of perceived descent increases as the observer views the stimulus from further in the periphery. We examine the first- and second-order information content in the display with the use of a three-dimensional Fourier analysis and show how our results can be used to describe perceived spatial/temporal discontinuities in real-world situations. The perceived shift of the disk's direction in the periphery is consistent with a model in which foveal processing separates first- and second-order motion information while peripheral processing integrates first- and second-order motion information. We argue that the perceived distortion may influence real-world visual observations. To this end, we present a hypothesis and analysis of the perception of the curveball and rising fastball in the sport of baseball. The curveball is a physically measurable phenomenon: the imbalance of forces created by the ball's spin causes the ball to deviate from a straight line and to follow a smooth parabolic path. However, the curveball is also a perceptual puzzle because batters often

Developmental visual perception deficits with no indications of prosopagnosia in a child with abnormal eye movements.

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Gilaie-Dotan, Sharon; Doron, Ravid

2017-06-01

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. Here, we studied BN, a 9 y.o. boy who has normal basic-level vision, abnormal (limited) oculomotor pursuit and saccades, and shows developmental object and contour integration deficits but with no indication of prosopagnosia. Although we cannot infer causation from the data presented here, we suggest that normal pursuit and saccades could be critical for the development of contour integration and object perception. While faces and perhaps reading, when fixated upon, take up a small portion of central visual field and require only small eye movements to be properly processed, common objects typically prevail in mid-peripheral visual field and rely on longer-distance voluntary eye movements as saccades to be brought to fixation. While retinal information feeds into early visual cortex in an eccentricity orderly manner, we hypothesize that propagation of non-foveal information to mid and high-order visual cortex critically relies on circuitry involving eye movements. Limited or atypical eye movements, as in the case of BN, may hinder normal information flow to mid-eccentricity biased high-order visual cortex, adversely affecting its development and consequently inducing visual perceptual deficits predominantly for categories associated with these regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functional MRI mapping of visual function and selective attention for performance assessment and presurgical planning using conjunctive visual search.

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Parker, Jason G; Zalusky, Eric J; Kirbas, Cemil

2014-03-01

Accurate mapping of visual function and selective attention using fMRI is important in the study of human performance as well as in presurgical treatment planning of lesions in or near visual centers of the brain. Conjunctive visual search (CVS) is a useful tool for mapping visual function during fMRI because of its greater activation extent compared with high-capacity parallel search processes. The purpose of this work was to develop and evaluate a CVS that was capable of generating consistent activation in the basic and higher level visual areas of the brain by using a high number of distractors as well as an optimized contrast condition. Images from 10 healthy volunteers were analyzed and brain regions of greatest activation and deactivation were determined using a nonbiased decomposition of the results at the hemisphere, lobe, and gyrus levels. The results were quantified in terms of activation and deactivation extent and mean z-statistic. The proposed CVS was found to generate robust activation of the occipital lobe, as well as regions in the middle frontal gyrus associated with coordinating eye movements and in regions of the insula associated with task-level control and focal attention. As expected, the task demonstrated deactivation patterns commonly implicated in the default-mode network. Further deactivation was noted in the posterior region of the cerebellum, most likely associated with the formation of optimal search strategy. We believe the task will be useful in studies of visual and selective attention in the neuroscience community as well as in mapping visual function in clinical fMRI.

Non-conscious visual cues related to affect and action alter perception of effort and endurance performance

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Anthony William Blanchfield

2014-12-01

Full Text Available The psychobiological model of endurance performance proposes that endurance performance is determined by a decision-making process based on perception of effort and potential motivation. Recent research has reported that effort-based decision-making during cognitive tasks can be altered by non-conscious visual cues relating to affect and action. The effect of these non-conscious visual cues on effort and performance during physical tasks is however unknown. We report two experiments investigating the effect of subliminal priming with visual cues related to affect and action on perception of effort and endurance performance. In Experiment 1 thirteen individuals were subliminally primed with happy or sad faces as they cycled to exhaustion in a counterbalanced and randomized crossover design. A paired t-test (happy vs. sad faces revealed that individuals cycled for significantly longer (178 s, p = .04 when subliminally primed with happy faces. A 2 x 5 (condition x iso-time ANOVA also revealed a significant main effect of condition on rating of perceived exertion (RPE during the time to exhaustion (TTE test with lower RPE when subjects were subliminally primed with happy faces (p = .04. In Experiment 2, a single-subject randomization tests design found that subliminal priming with action words facilitated a significantly longer (399 s, p = .04 TTE in comparison to inaction words (p = .04. Like Experiment 1, this greater TTE was accompanied by a significantly lower RPE (p = .03. These experiments are the first to show that subliminal visual cues relating to affect and action can alter perception of effort and endurance performance. Non-conscious visual cues may therefore influence the effort-based decision-making process that is proposed to determine endurance performance. Accordingly, the findings raise notable implications for individuals who may encounter such visual cues during endurance competitions, training, or health related exercise.

Improved custom statistics visualization for CA Performance Center data

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Talevi, Iacopo

2017-01-01

The main goal of my project is to understand and experiment the possibilities that CA Performance Center (CA PC) offers for creating custom applications to display stored information through interesting visual means, such as maps. In particular, I have re-written some of the network statistics web pages in order to fetch data from new statistics modules in CA PC, which has its own API, and stop using the RRD data.

The effects of equine peripheral blood stem cells on cutaneous wound healing: a clinical evaluation in four horses.

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Spaas, J H; Broeckx, S; Van de Walle, G R; Polettini, M

2013-04-01

Stem-cell therapy represents a promising strategy for the treatment of challenging pathologies, such as large, infected wounds that are unresponsive to conventional therapies. The present study describes the clinical application of peripheral blood stem cells (PBSCs) for the treatment of four adult Warmblood horses with naturally occurring wounds, which were unresponsive to conventional therapies for at least 3 months. A visual assessment was performed, and a number of wound-healing parameters (granulation tissue, crust formation and scar formation) were evaluated. In all cases, tissue overgrowth was visible within 4 weeks after PBSC injection, followed by the formation of crusts and small scars in the centre of the wound, with hair regeneration at the edges. In conclusion, this is the first report of PBSC therapy of skin wounds in horses, and it produced a positive visual and clinical outcome. © The Author(s) CED © 2013 British Association of Dermatologists.

Intraoperative digital angiography: Peripheral vascular applications

International Nuclear Information System (INIS)

Bell, K.; Reifsteck, J.E.; Binet, E.F.; Fleisher, H.J.

1986-01-01

Intraoperative digital angiography is the procedure of choice for the peripheral vascular surgeon who wishes to evaluate his results before terminating anesthesia. Two operating suites at the John L. McClellan Memorial Veterans Hospital are equipped with permanent ceiling-mounted Philips C-arm fluoroscopes and share an ADAC 4100 digital angiographic system. In the last 18 months, 40 peripheral vascular intraoperative digital angiographic procedures have been performed, in all but two cases using direct arterial puncture. In 65% of cases, the intraoperative study showed no significant abnormality. In 12.5%, minor abnormalities not requiring reoperation were seen. In 22.5% of cases, the intraoperative digital angiogram revealed a significant abnormality requiring immediate operative revision. None of the patients who underwent reoperation experienced postoperative sequelae. Intraoperative digital angiography is useful in identifying complications of peripheral vascular operations

Performance Measurement and Accommodation: Students with Visual Impairments on Pennsylvania's Alternate Assessment

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Zebehazy, Kim T.; Zigmond, Naomi; Zimmerman, George J.

2012-01-01

Introduction: This study investigated the use of accommodations and the performance of students with visual impairments and severe cognitive disabilities on the Pennsylvania Alternate System of Assessment (PASA)yCoan alternate performance-based assessment. Methods: Differences in test scores on the most basic level (level A) of the PASA of 286…

A visual analytics system for optimizing the performance of large-scale networks in supercomputing systems

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Takanori Fujiwara

2018-03-01

Full Text Available The overall efficiency of an extreme-scale supercomputer largely relies on the performance of its network interconnects. Several of the state of the art supercomputers use networks based on the increasingly popular Dragonfly topology. It is crucial to study the behavior and performance of different parallel applications running on Dragonfly networks in order to make optimal system configurations and design choices, such as job scheduling and routing strategies. However, in order to study these temporal network behavior, we would need a tool to analyze and correlate numerous sets of multivariate time-series data collected from the Dragonfly’s multi-level hierarchies. This paper presents such a tool–a visual analytics system–that uses the Dragonfly network to investigate the temporal behavior and optimize the communication performance of a supercomputer. We coupled interactive visualization with time-series analysis methods to help reveal hidden patterns in the network behavior with respect to different parallel applications and system configurations. Our system also provides multiple coordinated views for connecting behaviors observed at different levels of the network hierarchies, which effectively helps visual analysis tasks. We demonstrate the effectiveness of the system with a set of case studies. Our system and findings can not only help improve the communication performance of supercomputing applications, but also the network performance of next-generation supercomputers. Keywords: Supercomputing, Parallel communication network, Dragonfly networks, Time-series data, Performance analysis, Visual analytics

COMPARISON OF USER PERFORMANCE WITH INTERACTIVE AND STATIC 3D VISUALIZATION – PILOT STUDY

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L. Herman

2016-06-01

Full Text Available Interactive 3D visualizations of spatial data are currently available and popular through various applications such as Google Earth, ArcScene, etc. Several scientific studies have focused on user performance with 3D visualization, but static perspective views are used as stimuli in most of the studies. The main objective of this paper is to try to identify potential differences in user performance with static perspective views and interactive visualizations. This research is an exploratory study. An experiment was designed as a between-subject study and a customized testing tool based on open web technologies was used for the experiment. The testing set consists of an initial questionnaire, a training task and four experimental tasks. Selection of the highest point and determination of visibility from the top of a mountain were used as the experimental tasks. Speed and accuracy of each task performance of participants were recorded. The movement and actions in the virtual environment were also recorded within the interactive variant. The results show that participants deal with the tasks faster when using static visualization. The average error rate was also higher in the static variant. The findings from this pilot study will be used for further testing, especially for formulating of hypotheses and designing of subsequent experiments.

Simple method for culture of peripheral blood lymphocytes of Testudinidae.

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Silva, T L; Silva, M I A; Venancio, L P R; Zago, C E S; Moscheta, V A G; Lima, A V B; Vizotto, L D; Santos, J R; Bonini-Domingos, C R; Azeredo-Oliveira, M T V

2011-12-06

We developed and optimized a simple, efficient and inexpensive method for in vitro culture of peripheral blood lymphocytes from the Brazilian tortoise Chelonoidis carbonaria (Testudinidae), testing various parameters, including culture medium, mitogen concentration, mitotic index, culture volume, incubation time, and mitotic arrest. Peripheral blood samples were obtained from the costal vein of four couples. The conditions that gave a good mitotic index were lymphocytes cultured at 37°C in minimum essential medium (7.5 mL), with phytohemagglutinin as a mitogen (0.375 mL), plus streptomycin/penicillin (0.1 mL), and an incubation period of 72 h. Mitotic arrest was induced by 2-h exposure to colchicine (0.1 mL), 70 h after establishing the culture. After mitotic arrest, the cells were hypotonized with 0.075 M KCl for 2 h and fixed with methanol/acetic acid (3:1). The non-banded mitotic chromosomes were visualized by Giemsa staining. The diploid chromosome number of C. carbonaria was found to be 52 in females and males, and sex chromosomes were not observed. We were able to culture peripheral blood lymphocytes of a Brazilian tortoise in vitro, for the preparation of mitotic chromosomes.

Desempenho visual na correção de miopia com óculos e lentes de contato gelatinosas Visual performance in myopic correction with spectacles and soft contact lenses

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Breno Barth

2008-02-01

Full Text Available OBJETIVOS: Avaliar o desempenho visual, por meio da acuidade visual LogMAR de alto contraste, sensibilidade ao contraste e análise de frentes de onda de indivíduos portadores de miopia com ou sem astigmatismo, corrigidos com óculos e com três diferentes lentes de contato gelatinosas [Acuvue® 2 (Vistacon J&J Vision Care Inc., EUA, Biomedics® 55 (Ocular Science, EUA e Focus® 1-2 week (Ciba Vision Corporation, EUA]. MÉTODOS: Estudo clínico e prospectivo com intervenção em amostra constituída por quarenta indivíduos portadores de miopia entre -1,00 D e -4,50 D, sem ou com astigmatismo até -0,75 D. RESULTADOS: A sobrerefração objetiva realizada pelo aberrômetro Zywave detectou diferença significativa entre as lentes de contato gelatinosas Acuvue® 2 e Biomedics® 55, em relação aos componentes refrativos esfera e equivalente esférico, que se mostraram hipercorrigidos em relação às lentes de contato gelatinosas Focus® 1-2 week. A acuidade visual LogMAR e sensibilidade ao contraste não detectaram diferenças no desempenho visual com os óculos e com as três lentes de contato gelatinosas. A análise de frentes de onda detectou diferença significativa na aberração de terceira ordem sem e com as lentes de contato gelatinosas, com melhor desempenho visual com as lentes de contato gelatinosas Acuvue® 2 e Biomedics® 55. CONCLUSÕES: A análise de frentes de onda detectou diferenças no desempenho visual com óculos e com as lentes de contato gelatinosas, sendo, portanto, uma medida mais sensível da função visual que a acuidade visual LogMAR de alto contraste e a sensibilidade ao contraste. O modelo de avaliação de desempenho visual com análise de frentes de onda utilizado nesta investigação serve de modelo para pesquisas semelhantes.PURPOSE: To evaluate the visual performance by high contrast visual acuity, contrast sensitivity and wavefront in myopic patients with or without astigmatism corrected with spectacles and

Comparative proteomic analyses of macular and peripheral retina of cynomolgus monkeys (Macaca fascicularis).

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Okamoto, Haru; Umeda, Shinsuke; Nozawa, Takehiro; Suzuki, Michihiro T; Yoshikawa, Yasuhiro; Matsuura, Etsuko T; Iwata, Takeshi

2010-01-01

The central region of the primate retina is called the macula. The fovea is located at the center of the macula, where the photoreceptors are concentrated to create a neural network adapted for high visual acuity. Damage to the fovea, e.g., by macular dystrophies and age-related macular degeneration, can reduce central visual acuity. The molecular mechanisms leading to these diseases are most likely dependent on the proteins in the macula which differ from those in the peripheral retina in expression level. To investigate whether the distribution of proteins in the macula is different from the peripheral retina, proteomic analyses of tissues from these two regions of cynomolgus monkeys were compared. Two-dimensional gel electrophoresis and mass spectrometry identified 26 proteins that were present only in the macular gel spots. The expression levels of five proteins, cone photoreceptor specific arrestin-C, gamma-synuclein, epidermal fatty acid binding protein, tropomyosin 1alpha chain, and heterogeneous nuclear ribonucleoproteins A2/B1, were significantly higher in the macula than in the peripheral retina. Immunostaining of macula sections by antibodies to each identified protein revealed unique localization in the retina, retinal pigment epithelial cells and the choroidal layer. Some of these proteins were located in cells with higher densities in the macula. We suggest that it will be important to study these proteins to determine their contribution to the pathogenesis and progression of macula diseases.

Absent Audiovisual Integration Elicited by Peripheral Stimuli in Parkinson’s Disease

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Yanna Ren

2018-01-01

Full Text Available The basal ganglia, which have been shown to be a significant multisensory hub, are disordered in Parkinson’s disease (PD. This study was to investigate the audiovisual integration of peripheral stimuli in PD patients with/without sleep disturbances. Thirty-six age-matched normal controls (NC and 30 PD patients were recruited for an auditory/visual discrimination experiment. The mean response times for each participant were analyzed using repeated measures ANOVA and race model. The results showed that the response to all stimuli was significantly delayed for PD compared to NC (all p0.05. The current results showed that audiovisual multisensory integration for peripheral stimuli is absent in PD regardless of sleep disturbances and further suggested the abnormal audiovisual integration might be a potential early manifestation of PD.

Sudden visual loss after cardiac resynchronization therapy device implantation.

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De Vitis, Luigi A; Marchese, Alessandro; Giuffrè, Chiara; Carnevali, Adriano; Querques, Lea; Tomasso, Livia; Baldin, Giovanni; Maestranzi, Gisella; Lattanzio, Rosangela; Querques, Giuseppe; Bandello, Francesco

2017-03-10

To report a case of sudden decrease in visual acuity possibly due to a cardiogenic embolism in a patient who underwent cardiac resynchronization therapy (CRT) device implantation. A 62-year-old man with severe left ventricular systolic dysfunction and a left bundle branch block was referred to our department because of a sudden decrease in visual acuity. Nine days earlier, he had undergone cardiac transapical implantation of a CRT device, which was followed, 2 days later, by an inflammatory reaction. The patient underwent several general and ophthalmologic examinations, including multimodal imaging. At presentation, right eye (RE) best-corrected visual acuity (BCVA) was counting fingers and RE pupil was hyporeactive. Fundus examination revealed white-centered hemorrhagic dots suggestive of Roth spots. Fluorescein angiography showed delay in vascular perfusion during early stage, late hyperfluorescence of the macula and optic disk, and peripheral perivascular leakage. The first visual field test showed complete loss of vision RE and a normal left eye. Due to suspected giant cell arteritis, temporal artery biopsy was performed. Thirty minutes after the procedure, an ischemic stroke with right hemisyndrome and aphasia occurred. The RE BCVA worsened to hands motion. Four months later, RE BCVA did not improve, despite improvement in fluorescein angiography inflammatory sign. We report a possible cardiogenic embolism secondary to undiagnosed infective endocarditis causing monocular visual loss after CRT device implantation. It remains unclear how the embolus caused severe functional damage without altering the retinal anatomical structure.

Vasculitic peripheral neuropathy

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Mona Amini

2014-02-01

Full Text Available Primary systemic vasculitis in pre-capillary arteries is associated with peripheral neuropathy. In some types of systematic vasculitis about 60 % of patients have peripheral nervous system (PNS involvement. In vasculitic peripheral neuropathies (VPN a necrotizing and inflammatory process leads to narrowing of vasa nervorum lumen and eventually the appearance of ischemic lesions in peripheral nerves. Some features might be suggestive of VPN, like: axonal nerve degeneration, wallerian-like degeneration, and diameter irregularity of nerve. Peripheral nervous system (PNS destruction during systemic vasculitides should be considered, due to its frequency and early occurrence in vasculitis progression. The first line treatment of non systematic VPNs is corticosteroid agents, but these drugs might worsen the VPNs or systemic vasculitis.

Please Don't Move-Evaluating Motion Artifact From Peripheral Quantitative Computed Tomography Scans Using Textural Features.

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Rantalainen, Timo; Chivers, Paola; Beck, Belinda R; Robertson, Sam; Hart, Nicolas H; Nimphius, Sophia; Weeks, Benjamin K; McIntyre, Fleur; Hands, Beth; Siafarikas, Aris

Most imaging methods, including peripheral quantitative computed tomography (pQCT), are susceptible to motion artifacts particularly in fidgety pediatric populations. Methods currently used to address motion artifact include manual screening (visual inspection) and objective assessments of the scans. However, previously reported objective methods either cannot be applied on the reconstructed image or have not been tested for distal bone sites. Therefore, the purpose of the present study was to develop and validate motion artifact classifiers to quantify motion artifact in pQCT scans. Whether textural features could provide adequate motion artifact classification performance in 2 adolescent datasets with pQCT scans from tibial and radial diaphyses and epiphyses was tested. The first dataset was split into training (66% of sample) and validation (33% of sample) datasets. Visual classification was used as the ground truth. Moderate to substantial classification performance (J48 classifier, kappa coefficients from 0.57 to 0.80) was observed in the validation dataset with the novel texture-based classifier. In applying the same classifier to the second cross-sectional dataset, a slight-to-fair (κ = 0.01-0.39) classification performance was observed. Overall, this novel textural analysis-based classifier provided a moderate-to-substantial classification of motion artifact when the classifier was specifically trained for the measurement device and population. Classification based on textural features may be used to prescreen obviously acceptable and unacceptable scans, with a subsequent human-operated visual classification of any remaining scans. Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Recurrent central serous chorioretinopathy after peripheral retinal laser photocoagulation: a case report.

Science.gov (United States)

Semeraro, Francesco; Russo, Andrea; Delcassi, Luisa; Costagliola, Ciro

2013-01-01

To report a case of recurrent central serous chorioretinopathy (CSC) after performing peripheral laser photocoagulation for retinal degenerations. A 44-year-old woman with ocular history of CSC presented to the emergency room of our department complaining of heavy photopsia due to retinal tuft and lattice degenerations, and underwent laser photocoagulation to prevent retinal detachment. Two days after laser treatment, the visual acuity dropped, and optical coherence tomography scan showed the onset of CSC. The serous detachment completely resolved in 20 days with no therapy. A new CSC episode occurred in the same eye after another analogous laser treatment and, similarly, quickly resolved spontaneously. We reviewed the literature and discuss the possibility that laser-induced inflammation could rouse an inflammatory cascade mediated by proinflammatory cytokines and PAI-1, leading to the exacerbation of retinal serous detachment in susceptible patients.

Selective peripheral nerve resection for treatment of persistent pain around the knee joint after total knee arthroplasty.

Science.gov (United States)

Zhong, Guangjun; Liang, Zhu; Kan, Jiang; Muheremu, Aikeremujiang

2018-01-01

Objective This study was performed to determine the efficacy of selective peripheral nerve resection for treatment of persistent neuropathic pain after total knee arthroplasty (TKA). Methods Patients who underwent TKA in our department from January 2013 to July 2016 and experienced persistent pain around the knee joint after TKA were retrospectively included in the current study. Sixty patients were divided into experimental and control groups according the treatment they received. The treatment effect was evaluated by the Hospital for Special Surgery (HSS) knee score and visual analog scale (VAS) pain score preoperatively and at 1, 2, 3, 6, and 12 months postoperatively. Results The HSS knee scores were higher in both groups after than before the treatment, and HSS knee scores were significantly higher in the experimental group than in the control group. The VAS pain scores were lower in both groups after than before the treatment, and VAS pain scores were significantly lower in the experimental group than in the control group. Conclusions Selective peripheral nerve resection is an effective treatment method for persistent neuropathic pain after TKA.

Transcriptome data of peripheral white blood cells from beef heifers collected at the time of artificial insemination

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Sarah E. Dickinson

2018-06-01

Full Text Available The reproductive performance of heifers within their first breeding season influences the success of beef cattle operations. Therefore, a means to identify infertile and late breeding heifers before the start of the breeding season holds great promise for the future of the beef industry. Pubertal beef heifers were subjected to estrous synchronization and fixed time artificial insemination (FTAI. We collected peripheral blood from the heifers at the time of artificial insemination (AI and generated RNA sequencing data to characterize the transcriptome of peripheral white blood cells (PWBC. Following insemination, heifers were exposed to natural service for a defined breeding season, and pregnancy was evaluated to classify heifers into one of three groups: AI-pregnant, natural-bred (NB pregnant, and non-pregnant. The raw transcriptome data of PWBC is available on the NCBI GEO repository (GSE103628 where the reader can also find raw read counts and normalized gene expression data. The normalized data on transcript coverage can be visualized as a genome browser at HeiferFertilityRNAseq.org. Keywords: Biomarkers, Infertility, Pregnancy

Visual and auditory digit-span performance in native and nonnative speakers

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Olsthoorn, N.M.; Andringa, S.; Hulstijn, J.H.

2014-01-01

We compared 121 native and 114 non-native speakers of Dutch (with 35 different first languages) on four digit-span tasks, varying modality (visual/auditory) and direction (forward/backward). An interaction was observed between nativeness and modality, such that, while natives performed better than

Teach yourself visually OS X Mavericks

CERN Document Server

McFedries, Paul

2013-01-01

Clear, step-by-step instruction guides you through OS X Mavericks If you want to get quickly up to speed on the newest (and now cat-free) OS X operating system, OS X Mavericks, this easy-to-follow book is just the ticket. Designed for visual learners, Teach Yourself VISUALLY OS X Mavericks uses rich, full-color screenshots and illustrations to show rather than tell you how to use Mavericks. You'll learn how to customize your Mac, enjoy digital media, connect common peripherals, and get the most out of the very latest enhancements, including iBooks, Maps, iCloud, and Calendar. Shows you how t

A new measure for the assessment of visual awareness in individuals with tunnel vision.

Science.gov (United States)

AlSaqr, Ali M; Dickinson, Chris M

2017-01-01

Individuals with a restricted peripheral visual field or tunnel vision (TV) have problems moving about and avoiding obstacles. Some individuals adapt better than others and some use assistive optical aids, so measurement of the visual field is not sufficient to describe their performance. In the present study, we developed a new clinical test called the 'Assessment of Visual Awareness (AVA)', which can be used to measure detection of peripheral targets. The participants were 20 patients with TV due to retinitis pigmentosa (PTV) and 50 normally sighted participants with simulated tunnel vision (STV) using goggles. In the AVA test, detection times were measured, when subjects searched for 24 individually presented, one degree targets, randomly positioned in a 60 degrees noise background. Head and eye movements were allowed and the presentation time was unlimited. The test validity was investigated by correlating the detection times with the 'percentage of preferred walking speed' (PPWS) and the 'number of collisions' on an indoor mobility course. In PTV and STV, the detection times had significant negative correlation with the field of view. The detection times had significant positive relations with target location. In the STV, the detection time was significantly negatively correlated with the PPWS and significantly positively correlated with the collisions score on the indoor mobility course. In the PTV, the relationship was not statistically significant. No significant difference in performance of STV was found when repeating the test one to two weeks later. The proposed AVA test was sensitive to the field of view and target location. The test is unique in design, quick, simple to deliver and both repeatable and valid. It could be a valuable tool to test different rehabilitation strategies in patients with TV. © 2016 Optometry Australia.

Secondary visual workload capability with primary visual and kinesthetic-tactual displays

Science.gov (United States)

Gilson, R. D.; Burke, M. W.; Jagacinski, R. J.

1978-01-01

Subjects performed a cross-adaptive tracking task with a visual secondary display and either a visual or a quickened kinesthetic-tactual (K-T) primary display. The quickened K-T display resulted in superior secondary task performance. Comparisons of secondary workload capability with integrated and separated visual displays indicated that the superiority of the quickened K-T display was not simply due to the elimination of visual scanning. When subjects did not have to perform a secondary task, there was no significant difference between visual and quickened K-T displays in performing a critical tracking task.

Learning temporal context shapes prestimulus alpha oscillations and improves visual discrimination performance.

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Toosi, Tahereh; K Tousi, Ehsan; Esteky, Hossein

2017-08-01

Time is an inseparable component of every physical event that we perceive, yet it is not clear how the brain processes time or how the neuronal representation of time affects our perception of events. Here we asked subjects to perform a visual discrimination task while we changed the temporal context in which the stimuli were presented. We collected electroencephalography (EEG) signals in two temporal contexts. In predictable blocks stimuli were presented after a constant delay relative to a visual cue, and in unpredictable blocks stimuli were presented after variable delays relative to the visual cue. Four subsecond delays of 83, 150, 400, and 800 ms were used in the predictable and unpredictable blocks. We observed that predictability modulated the power of prestimulus alpha oscillations in the parieto-occipital sites: alpha power increased in the 300-ms window before stimulus onset in the predictable blocks compared with the unpredictable blocks. This modulation only occurred in the longest delay period, 800 ms, in which predictability also improved the behavioral performance of the subjects. Moreover, learning the temporal context shaped the prestimulus alpha power: modulation of prestimulus alpha power grew during the predictable block and correlated with performance enhancement. These results suggest that the brain is able to learn the subsecond temporal context of stimuli and use this to enhance sensory processing. Furthermore, the neural correlate of this temporal prediction is reflected in the alpha oscillations. NEW & NOTEWORTHY It is not well understood how the uncertainty in the timing of an external event affects its processing, particularly at subsecond scales. Here we demonstrate how a predictable timing scheme improves visual processing. We found that learning the predictable scheme gradually shaped the prestimulus alpha power. These findings indicate that the human brain is able to extract implicit subsecond patterns in the temporal context of

Clinical study of the visual field defects caused by occipital lobe lesions.

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Ogawa, Katsuhiko; Ishikawa, Hiroshi; Suzuki, Yutaka; Oishi, Minoru; Kamei, Satoshi

2014-01-01

The central visual field is projected to the region from the occipital tip to the posterior portion of the medial area in the striate cortex. However, central visual field disturbances have not been compared with the location of the lesions in the striate cortex. Thirteen patients with visual field defects caused by partial involvement of the striate cortex were enrolled. The lesions were classified according to their location into the anterior portion, the posterior portion of the medial area, and the occipital tip. Visual field defects were examined by the Goldmann perimetry, the Humphrey perimetry and the auto-plot tangent screen. We defined a defect within the central 10° of vision as a central visual field disturbance. The visual field defects in 13 patients were compared with the location of their lesions in the striate cortex. The medial area was involved in 7 patients with no involvement of the occipital tip. In 2 of them, peripheral homonymous hemianopia without central visual field disturbance was shown, and their lesions were located only in the anterior portion. One patient with a lesion in the posterior portion alone showed incomplete central homonymous hemianopia. Three of 4 patients with lesions located in both the anterior and posterior portions of the medial area showed incomplete central homonymous hemianopia and peripheral homonymous hemianopia. The occipital tip was involved in 6 patients. Five of them had small lesions in the occipital tip alone and showed complete central homonymous hemianopia or quadrantanopia. The other patient with a lesion in the lateral posterior portion and bilateral occipital tip lesions showed bilateral slight peripheral visual field disturbance in addition to complete central homonymous hemianopia on both sides. Lesions in the posterior portion of the medial area as well as the occipital tip caused central visual field disturbance in our study, as indicated in previous reports. Central homonymous hemianopia tended to

Peripheral biomarkers revisited: integrative profiling of peripheral samples for psychiatric research.

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Hayashi-Takagi, Akiko; Vawter, Marquis P; Iwamoto, Kazuya

2014-06-15

Peripheral samples, such as blood and skin, have been used for decades in psychiatric research as surrogates for central nervous system samples. Although the validity of the data obtained from peripheral samples has been questioned and other state-of-the-art techniques, such as human brain imaging, genomics, and induced pluripotent stem cells, seem to reduce the value of peripheral cells, accumulating evidence has suggested that revisiting peripheral samples is worthwhile. Here, we re-evaluate the utility of peripheral samples and argue that establishing an understanding of the common signaling and biological processes in the brain and peripheral samples is required for the validity of such models. First, we present an overview of the available types of peripheral cells and describe their advantages and disadvantages. We then briefly summarize the main achievements of omics studies, including epigenome, transcriptome, proteome, and metabolome analyses, as well as the main findings of functional cellular assays, the results of which imply that alterations in neurotransmission, metabolism, the cell cycle, and the immune system may be partially responsible for the pathophysiology of major psychiatric disorders such as schizophrenia. Finally, we discuss the future utility of peripheral samples for the development of biomarkers and tailor-made therapies, such as multimodal assays that are used as a battery of disease and trait pathways and that might be potent and complimentary tools for use in psychiatric research. © 2013 Society of Biological Psychiatry Published by Society of Biological Psychiatry All rights reserved.

Summary receiver operating characteristic curves as a technique for meta-analysis of the diagnostic performance of duplex ultrasonography in peripheral arterial disease

NARCIS (Netherlands)

deVries, SO; Hunink, MGM; Polak, JF

Rationale and Objectives. We summarized and compared the diagnostic performance of duplex and color-guided duplex ultrasonography in the evaluation of peripheral arterial disease. We present our research as an example of the use of summary receiver operating characteristic (ROC) curves in a

Visual perspective in autobiographical memories: reliability, consistency, and relationship to objective memory performance.

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Siedlecki, Karen L

2015-01-01

Visual perspective in autobiographical memories was examined in terms of reliability, consistency, and relationship to objective memory performance in a sample of 99 individuals. Autobiographical memories may be recalled from two visual perspectives--a field perspective in which individuals experience the memory through their own eyes, or an observer perspective in which individuals experience the memory from the viewpoint of an observer in which they can see themselves. Participants recalled nine word-cued memories that differed in emotional valence (positive, negative and neutral) and rated their memories on 18 scales. Results indicate that visual perspective was the most reliable memory characteristic overall and is consistently related to emotional intensity at the time of recall and amount of emotion experienced during the memory. Visual perspective is unrelated to memory for words, stories, abstract line drawings or faces.

Intermittent pneumatic leg compressions enhance muscle performance and blood flow in a model of peripheral arterial insufficiency.

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Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Yang, Hsiao T; Terjung, Ronald; Laughlin, M H

2012-05-01

Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this therapy, remain poorly defined. We tested the hypothesis that 2 wk of daily application of IPC enhances exercise tolerance by improving blood flow and promoting angiogenesis in skeletal muscle in a model of peripheral arterial insufficiency. Male Sprague-Dawley rats were subjected to bilateral ligation of the femoral artery and randomly allocated to treatment or sham groups. Animals were anesthetized daily and exposed to 1-h sessions of bilateral IPC or sham treatment for 14-16 consecutive days. A third group of nonligated rats was also studied. Marked increases in treadmill exercise tolerance (∼33%, P < 0.05) and improved muscle performance in situ (∼10%, P < 0.05) were observed in IPC-treated animals. Compared with sham-treated controls, blood flow measured with isotope-labeled microspheres during in situ contractions tended to be higher in IPC-treated animals in muscles composed of predominantly fast-twitch white fibers, such as the plantaris (∼93%, P = 0.02). Capillary contacts per fiber and citrate synthase activity were not significantly altered by IPC treatment. Collectively, these data indicate that IPC improves exercise tolerance in a model of peripheral arterial insufficiency in part by enhancing blood flow to collateral-dependent tissues.

Phases of daylight and the stability of color perception in the near peripheral human retina.

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Panorgias, Athanasios; Kulikowski, Janus J; Parry, Neil R A; McKeefry, Declan J; Murray, Ian J

2012-03-01

Typical daylight extends from blue (morning sky) to orangey red (evening sky) and is represented mathematically as the Daylight Locus in color space. In this study, we investigate the impact of this daylight variation on human color vision. Thirty-eight color normal human observers performed an asymmetric color match in the near peripheral visual field. Unique hues were identified using a naming paradigm. The observers' performance for matching was almost perfectly coincident with the Daylight Locus but declined markedly in other regions. Interobserver variability reached a conspicuous minimum adjacent to the Daylight Locus and was maximal in the red and yellowish-green regions. In the naming task, unique blue and yellow were virtually coincident with the Daylight Locus. The results suggest that the mechanisms of color perception mediated by the phylogenetically older (blue-yellow) color pathway have been strongly influenced by the different phases of daylight.

The role of peripheral vision in saccade planning: learning from people with tunnel vision.

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Luo, Gang; Vargas-Martin, Fernando; Peli, Eli

2008-12-22

Both visually salient and top-down information are important in eye movement control, but their relative roles in the planning of daily saccades are unclear. We investigated the effect of peripheral vision loss on saccadic behaviors in patients with tunnel vision (visual field diameters 7 degrees-16 degrees) in visual search and real-world walking experiments. The patients made up to two saccades per second to their pre-saccadic blind areas, about half of which had no overlap between the post- and pre-saccadic views. In the visual search experiment, visual field size and the background (blank or picture) did not affect the saccade sizes and direction of patients (n = 9). In the walking experiment, the patients (n = 5) and normal controls (n = 3) had similar distributions of saccade sizes and directions. These findings might provide a clue about the large extent of the top-down mechanism influence on eye movement control.

Visual Impairment Secondary to Unilateral Isolated Epicapsular Star

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Mehmet Serhat Mangan

2014-12-01

Full Text Available We aimed to report a rarely observed case of unilateral epicapsular star and the visual impairment developed secondary to it. A 8-year-old girl presented with a complaint of blurred vision in the right eye; best-corrected visual acuity was 0.7 in the right eye and 1.0 in the left eye. Near visual acuity was J1 in the right eye and J1+ in the left eye. The patient had no systemic disease and no clinical findings such as ocular inflammation, trauma, or history of use of topical and systemic drug. On biomicroscopic examination, no pigment deposition was observed in the cornea of both eyes and anterior chamber was normal. The anterior capsule of the lens in the right eye demonstrated dense pigment depositions centrally which were obscuring the pupillary axis. Iris translumination defect was not seen. Gonioscopy was performed and no pigment deposition was seen in the iridocorneal angle. Fundus examination revealed no pathology in the vitreous, posterior pole, and peripheral retina. In the absence of signs of intraocular inflammation and other causes of primary or secondary pigment dispersion, it is likely that the pigmented cells were implanted on the lens surface in utero from the developing iris pigment epithelium. In such cases, visual impairment should be detected in early period, and the strict follow-up is of utmost importance. (Turk J Ophthalmol 2014; 44: 493-5

Computerized evaluation of deambulatory pattern before and after visual rehabilitation treatment performed with biofeedback in visually impaired patients suffering from macular degeneration

Directory of Open Access Journals (Sweden)

Fernanda Pacella

2016-09-01

Full Text Available Aims: The aim of this study was double: the primary endpoint was to evaluate the efficacy of visual rehabilitation of visually impaired patients with macular degeneration (AMD. The secondary endpoint was to assess the effect of rehabilitation treatment on the ambulatory pattern using a computerized evaluation of walking, focusing the attention on space-time parameters that are influenced in patients with visual impairment. Methods: 10 patients with AMD were enrolled, 6 males and 4 females, and examined 15 eyes, at Department of Sense Organs, Faculty of Medicine and Dentistry Sapienza University of Rome, Italy. Visual rehabilitation was carried out with the use of a microperimeter MP1 using the examination of biofeedback. Patients are asked to move their eyes in coordination with an audible feedback that alerts the patient when he is setting properly the fixation target previously selected. All patients were subjected to 10 sessions lasting 15 minutes each for each eye, 1 time per week. The best corrected visual acuity (BCVA was assessed by far with the ETDRS optotype IN LOG MAR, and by close to 25 cm by adding + 4 ball (addition to near to the BCVA. For each eye the PB ( print body on the distance of 25 cm was measured; It fixation stability for 30 seconds was examined by microperimeter. Gait Analysis was performed with system ELITE BTS SpA (Milan, Italy. Results: At the end of the rehabilitation treatment with biofeedback it was found a marked improvement in BCVA. The BCVA before the rehabilitation treatment was ETDRS 12 LETTERS = 0.86 logMAR. At the end of the visual rehabilitation 16 LETTERS = 0.78 logMAR. The near visual acuity presented a decrease of the printer body measurement (PB and a statistically significant improvement in the fixation stability. Analysis of the spatial and temporal parameters of gait cycle, aimed at assessing the global aspects of gait (speed, rhythm, symmetry, fluidity, dynamic balance showed no significant changes

Visualizing weighted networks: a performance comparison of adjacency matrices versus node-link diagrams

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McIntire, John P.; Osesina, O. Isaac; Bartley, Cecilia; Tudoreanu, M. Eduard; Havig, Paul R.; Geiselman, Eric E.

2012-06-01

Ensuring the proper and effective ways to visualize network data is important for many areas of academia, applied sciences, the military, and the public. Fields such as social network analysis, genetics, biochemistry, intelligence, cybersecurity, neural network modeling, transit systems, communications, etc. often deal with large, complex network datasets that can be difficult to interact with, study, and use. There have been surprisingly few human factors performance studies on the relative effectiveness of different graph drawings or network diagram techniques to convey information to a viewer. This is particularly true for weighted networks which include the strength of connections between nodes, not just information about which nodes are linked to other nodes. We describe a human factors study in which participants performed four separate network analysis tasks (finding a direct link between given nodes, finding an interconnected node between given nodes, estimating link strengths, and estimating the most densely interconnected nodes) on two different network visualizations: an adjacency matrix with a heat-map versus a node-link diagram. The results should help shed light on effective methods of visualizing network data for some representative analysis tasks, with the ultimate goal of improving usability and performance for viewers of network data displays.

Changes in Drivers’ Visual Performance during the Collision Avoidance Process as a Function of Different Field of Views at Intersections

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Yan, Xuedong; Zhang, Xinran; Zhang, Yuting; Li, Xiaomeng; Yang, Zhuo

2016-01-01

The intersection field of view (IFOV) indicates an extent that the visual information can be observed by drivers. It has been found that further enhancing IFOV can significantly improve emergent collision avoidance performance at intersections, such as faster brake reaction time, smaller deceleration rate, and lower traffic crash involvement risk. However, it is not known how IFOV affects drivers’ eye movements, visual attention and the relationship between visual searching and traffic safety. In this study, a driving simulation experiment was conducted to uncover the changes in drivers’ visual performance during the collision avoidance process as a function of different field of views at an intersection by using an eye tracking system. The experimental results showed that drivers’ ability in identifying the potential hazard in terms of visual searching was significantly affected by different IFOV conditions. As the IFOVs increased, drivers had longer gaze duration (GD) and more number of gazes (NG) in the intersection surrounding areas and paid more visual attention to capture critical visual information on the emerging conflict vehicle, thus leading to a better collision avoidance performance and a lower crash risk. It was also found that female drivers had a better visual performance and a lower crash rate than male drivers. From the perspective of drivers’ visual performance, the results strengthened the evidence that further increasing intersection sight distance standards should be encouraged for enhancing traffic safety. PMID:27716824

Peripheral refraction in normal infant rhesus monkeys

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Hung, Li-Fang; Ramamirtham, Ramkumar; Huang, Juan; Qiao-Grider, Ying; Smith, Earl L.

2008-01-01

Purpose To characterize peripheral refractions in infant monkeys. Methods Cross-sectional data for horizontal refractions were obtained from 58 normal rhesus monkeys at 3 weeks of age. Longitudinal data were obtained for both the vertical and horizontal meridians from 17 monkeys. Refractive errors were measured by retinoscopy along the pupillary axis and at eccentricities of 15, 30, and 45 degrees. Axial dimensions and corneal power were measured by ultrasonography and keratometry, respectively. Results In infant monkeys, the degree of radial astigmatism increased symmetrically with eccentricity in all meridians. There were, however, initial nasal-temporal and superior-inferior asymmetries in the spherical-equivalent refractive errors. Specifically, the refractions in the temporal and superior fields were similar to the central ametropia, but the refractions in the nasal and inferior fields were more myopic than the central ametropia and the relative nasal field myopia increased with the degree of central hyperopia. With age, the degree of radial astigmatism decreased in all meridians and the refractions became more symmetrical along both the horizontal and vertical meridians; small degrees of relative myopia were evident in all fields. Conclusions As in adult humans, refractive error varied as a function of eccentricity in infant monkeys and the pattern of peripheral refraction varied with the central refractive error. With age, emmetropization occurred for both central and peripheral refractive errors resulting in similar refractions across the central 45 degrees of the visual field, which may reflect the actions of vision-dependent, growth-control mechanisms operating over a wide area of the posterior globe. PMID:18487366

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity.

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Künstler, E C S; Finke, K; Günther, A; Klingner, C; Witte, O; Bublak, P

2018-01-01

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the 'theory of visual attention' (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual short-term memory (VSTM) storage capacity. Moreover, goodness-of-fit values and bootstrapping estimates were derived to test whether the TVA-model is validly applicable also under dual task conditions, and whether the robustness of parameter estimates is comparable in single- and dual-task conditions. 24 subjects of middle to higher age performed a continuous tapping task, and a visual processing task (whole report of briefly presented letter arrays) under both single- and dual-task conditions. Results suggest a decline of both visual processing capacity and VSTM storage capacity under dual-task conditions, while the perceptual threshold remained unaffected by a concurrent motor task. In addition, goodness-of-fit values and bootstrapping estimates support the notion that participants processed the visual task in a qualitatively comparable, although quantitatively less efficient way under dual-task conditions. The results support a capacity sharing account of motor-cognitive dual tasking and suggest that even performing a relatively simple motor task relies on central attentional capacity that is necessary for efficient visual information uptake.

Perceptual Learning in Children With Infantile Nystagmus: Effects on Visual Performance.

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Huurneman, Bianca; Boonstra, F Nienke; Goossens, Jeroen

2016-08-01

To evaluate whether computerized training with a crowded or uncrowded letter-discrimination task reduces visual impairment (VI) in 6- to 11-year-old children with infantile nystagmus (IN) who suffer from increased foveal crowding, reduced visual acuity, and reduced stereopsis. Thirty-six children with IN were included. Eighteen had idiopathic IN and 18 had oculocutaneous albinism. These children were divided in two training groups matched on age and diagnosis: a crowded training group (n = 18) and an uncrowded training group (n = 18). Training occurred two times per week during 5 weeks (3500 trials per training). Eleven age-matched children with normal vision were included to assess baseline differences in task performance and test-retest learning. Main outcome measures were task-specific performance, distance and near visual acuity (DVA and NVA), intensity and extent of (foveal) crowding at 5 m and 40 cm, and stereopsis. Training resulted in task-specific improvements. Both training groups also showed uncrowded and crowded DVA improvements (0.10 ± 0.02 and 0.11 ± 0.02 logMAR) and improved stereopsis (670 ± 249″). Crowded NVA improved only in the crowded training group (0.15 ± 0.02 logMAR), which was also the only group showing a reduction in near crowding intensity (0.08 ± 0.03 logMAR). Effects were not due to test-retest learning. Perceptual learning with or without distractors reduces the extent of crowding and improves visual acuity in children with IN. Training with distractors improves near vision more than training with single optotypes. Perceptual learning also transfers to DVA and NVA under uncrowded and crowded conditions and even stereopsis. Learning curves indicated that improvements may be larger after longer training.

Sports Stars: Analyzing the Performance of Astronomers at Visualization-based Discovery

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Fluke, C. J.; Parrington, L.; Hegarty, S.; MacMahon, C.; Morgan, S.; Hassan, A. H.; Kilborn, V. A.

2017-05-01

In this data-rich era of astronomy, there is a growing reliance on automated techniques to discover new knowledge. The role of the astronomer may change from being a discoverer to being a confirmer. But what do astronomers actually look at when they distinguish between “sources” and “noise?” What are the differences between novice and expert astronomers when it comes to visual-based discovery? Can we identify elite talent or coach astronomers to maximize their potential for discovery? By looking to the field of sports performance analysis, we consider an established, domain-wide approach, where the expertise of the viewer (i.e., a member of the coaching team) plays a crucial role in identifying and determining the subtle features of gameplay that provide a winning advantage. As an initial case study, we investigate whether the SportsCode performance analysis software can be used to understand and document how an experienced Hi astronomer makes discoveries in spectral data cubes. We find that the process of timeline-based coding can be applied to spectral cube data by mapping spectral channels to frames within a movie. SportsCode provides a range of easy to use methods for annotation, including feature-based codes and labels, text annotations associated with codes, and image-based drawing. The outputs, including instance movies that are uniquely associated with coded events, provide the basis for a training program or team-based analysis that could be used in unison with discipline specific analysis software. In this coordinated approach to visualization and analysis, SportsCode can act as a visual notebook, recording the insight and decisions in partnership with established analysis methods. Alternatively, in situ annotation and coding of features would be a valuable addition to existing and future visualization and analysis packages.

Peripheral reactions

International Nuclear Information System (INIS)

Greiner, D.

1978-01-01

Peripheral collisions, that is, collisions involving a small amount of overlap of nuclear matter, are discussed including inclusive interactions, the magnitude of the peripheral cross section, fragmentation, a compilation of experiments and available data, limiting fragmentation, factorization, some models, fragment momentum distributions, and future research directions

Attention to body-parts varies with visual preference and verb-effector associations.

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Boyer, Ty W; Maouene, Josita; Sethuraman, Nitya

2017-05-01

Theories of embodied conceptual meaning suggest fundamental relations between others' actions, language, and our own actions and visual attention processes. Prior studies have found that when people view an image of a neutral body in a scene they first look toward, in order, the head, torso, hands, and legs. Other studies show associations between action verbs and the body-effectors used in performing the action (e.g., "jump" with feet/legs; "talk" with face/head). In the present experiment, the visual attention of participants was recorded with a remote eye-tracking system while they viewed an image of an actor pantomiming an action and heard a concrete action verb. Participants manually responded whether or not the action image was a good example of the verb they heard. The eye-tracking results confirmed that participants looked at the head most, followed by the hands, and the feet least of all; however, visual attention to each of the body-parts also varied as a function of the effector associated with the spoken verb on image/verb congruent trials, particularly for verbs associated with the legs. Overall, these results suggest that language influences some perceptual processes; however, hearing auditory verbs did not alter the previously reported fundamental hierarchical sequence of directed attention, and fixations on specific body-effectors may not be essential for verb comprehension as peripheral visual cues may be sufficient to perform the task.

Sensor-Based Interactive Balance Training with Visual Joint Movement Feedback for Improving Postural Stability in Diabetics with Peripheral Neuropathy: A Randomized Controlled Trial.

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Grewal, Gurtej Singh; Schwenk, Michael; Lee-Eng, Jacqueline; Parvaneh, Saman; Bharara, Manish; Menzies, Robert A; Talal, Talal K; Armstrong, David G; Najafi, Bijan

2015-01-01

Individuals with diabetic peripheral neuropathy (DPN) have deficits in sensory and motor skills leading to inadequate proprioceptive feedback, impaired postural balance and higher fall risk. This study investigated the effect of sensor-based interactive balance training on postural stability and daily physical activity in older adults with diabetes. Thirty-nine older adults with DPN were enrolled (age 63.7 ± 8.2 years, BMI 30.6 ± 6, 54% females) and randomized to either an intervention (IG) or a control (CG) group. The IG received sensor-based interactive exercise training tailored for people with diabetes (twice a week for 4 weeks). The exercises focused on shifting weight and crossing virtual obstacles. Body-worn sensors were implemented to acquire kinematic data and provide real-time joint visual feedback during the training. Outcome measurements included changes in center of mass (CoM) sway, ankle and hip joint sway measured during a balance test while the eyes were open and closed at baseline and after the intervention. Daily physical activities were also measured during a 48-hour period at baseline and at follow-up. Analysis of covariance was performed for the post-training outcome comparison. Compared with the CG, the patients in the IG showed a significantly reduced CoM sway (58.31%; p = 0.009), ankle sway (62.7%; p = 0.008) and hip joint sway (72.4%; p = 0.017) during the balance test with open eyes. The ankle sway was also significantly reduced in the IG group (58.8%; p = 0.037) during measurements while the eyes were closed. The number of steps walked showed a substantial but nonsignificant increase (+27.68%; p = 0.064) in the IG following training. The results of this randomized controlled trial demonstrate that people with DPN can significantly improve their postural balance with diabetes-specific, tailored, sensor-based exercise training. The results promote the use of wearable technology in exercise training; however, future studies comparing this

Is Visual Selective Attention in Deaf Individuals Enhanced or Deficient? The Case of the Useful Field of View

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Dye, Matthew W. G.; Hauser, Peter C.; Bavelier, Daphne

2009-01-01

Background Early deafness leads to enhanced attention in the visual periphery. Yet, whether this enhancement confers advantages in everyday life remains unknown, as deaf individuals have been shown to be more distracted by irrelevant information in the periphery than their hearing peers. Here, we show that, in a complex attentional task, a performance advantage results for deaf individuals. Methodology/Principal Findings We employed the Useful Field of View (UFOV) which requires central target identification concurrent with peripheral target localization in the presence of distractors – a divided, selective attention task. First, the comparison of deaf and hearing adults with or without sign language skills establishes that deafness and not sign language use drives UFOV enhancement. Second, UFOV performance was enhanced in deaf children, but only after 11 years of age. Conclusions/Significance This work demonstrates that, following early auditory deprivation, visual attention resources toward the periphery slowly get augmented to eventually result in a clear behavioral advantage by pre-adolescence on a selective visual attention task. PMID:19462009

The peripheral artery questionnaire: a new disease-specific health status measure for patients with peripheral arterial disease.

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Spertus, John; Jones, Philip; Poler, Sherri; Rocha-Singh, Krishna

2004-02-01

The most common indication for treating patients with peripheral arterial disease is to improve their health status: their symptoms, function, and quality of life. Quantifying health status requires a valid, reproducible, and sensitive disease-specific measure. The Peripheral Artery Questionnaire (PAQ) is a 20-item questionnaire developed to meet this need by quantifying patients' physical limitations, symptoms, social function, treatment satisfaction, and quality of life. Psychometric and clinical properties of the PAQ were evaluated in a prospective cohort study of 44 patients undergoing elective percutaneous peripheral revascularization. To establish reproducibility, 2 assessments were performed 2 weeks apart and before revascularization. The change in scores before and 6 weeks after revascularization were used to determine the instruments' responsiveness and were compared with the Short Form-36 and the Walking Impairment Questionnaire. A series of cross-sectional analyses were performed to establish the construct validity of the PAQ. The 7 domains of the PAQ were internally reliable, with Cronbach alpha = 0.80 to 0.94. The test-retest reliability analyses revealed insignificant mean changes of 0.6 to 2.3 points (P = not significant for all). Conversely, the change after revascularization ranged from 13.7 to 41.9 points (P PAQ to clinical improvement. The PAQ Summary Scale was the most sensitive of all scales tested. Construct validity was established by demonstrating correlations with other measures of patient health status. The PAQ is a valid, reliable, and responsive disease-specific measure for patients with peripheral arterial disease. It may prove to be a useful end point in clinical trials and a potential aid in disease management.

Peripheral Developing Odontoma or Peripheral Ameloblastic Fibroodontoma: A Rare Challenging Case

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Saede Atarbashi Moghadam

2016-01-01

Full Text Available Peripheral odontogenic lesions are considered to be rare within the classification of odontogenic tumors. They share the same microscopic characteristics of their central counterparts. Here, we report an ulcerated mass of the maxillary gingiva that on histopathological examination was diagnosed as peripheral developing odontoma or peripheral ameloblastic fibroodontoma. The diagnosis of this tumor is challenging and may lead to unnecessary treatment.

Examining Vision and Attention in Sports Performance Using a Gaze-Contingent Paradigm

Directory of Open Access Journals (Sweden)

Donghyun Ryu

2012-10-01

Full Text Available In time-constrained activities, such as competitive sports, the rapid acquisition and comprehension of visual information is vital for successful performance. Currently our understanding of how and what visual information is acquired and how this changes with skill development is quite rudimentary. Interpretation of eye movement behaviour is limited by uncertainties surrounding the relationship between attention, line-of-gaze data, and the mechanism of information pick-up from different sectors of the visual field. We used gaze-contingent display methodology to provide a selective information presentation to the central and peripheral parts of the visual field while performing a decision-making task. Eleven skilled and 11 less-skilled players watched videos of basketball scenarios under three different vision conditions (tunnel, masked, and full vision and in a forced-choice paradigm responded whether it was more appropriate for the ball carrier to pass or drive. In the tunnel and mask conditions vision was selectively restricted to, or occluded from, 5o around the line of gaze respectively. The skilled players showed significantly higher response accuracy and faster response times compared to their lesser skilled counterparts irrespective of the vision condition, demonstrating the skilled players' superiority in information extraction irrespective of the segment of visual field they rely on. Findings suggest that the capability to interpret visual information appears to be the key limiting factor to expert performance rather than the sector of the visual field in which the information is detected.

Performance of an iPad Application to Detect Moderate and Advanced Visual Field Loss in Nepal.

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Johnson, Chris A; Thapa, Suman; George Kong, Yu Xiang; Robin, Alan L

2017-10-01

To evaluate the accuracy and efficiency of Visual Fields Easy (VFE), a free iPad app, for performing suprathreshold perimetric screening. Prospective, cross-sectional validation study. We performed screening visual fields using a calibrated iPad 2 with the VFE application on 206 subjects (411 eyes): 210 normal (NL), 183 glaucoma (GL), and 18 diabetic retinopathy (DR) at Tilganga Institute of Ophthalmology, Kathmandu, Nepal. We correlated the results with a Humphrey Field Analyzer using 24-2 SITA Standard tests on 373 of these eyes (198 NL, 160 GL, 15 DR). The number of missed locations on the VFE correlated with mean deviation (MD, r = 0.79), pattern standard deviation (PSD, r = 0.60), and number of locations that were worse than the 95% confidence limits for total deviation (r = 0.51) and pattern deviation (r = 0.68) using SITA Standard. iPad suprathreshold perimetry was able to detect most visual field deficits with moderate (MD of -6 to -12 dB) and advanced (MD worse than -12 dB) loss, but had greater difficulty in detecting early (MD better than -6 dB) loss, primarily owing to an elevated false-positive response rate. The average time to perform the Visual Fields Easy test was 3 minutes, 18 seconds (standard deviation = 16.88 seconds). The Visual Fields Easy test procedure is a portable, fast, effective procedure for detecting moderate and advanced visual field loss. Improvements are currently underway to monitor eye and head tracking during testing, reduce testing time, improve performance, and eliminate the need to touch the video screen surface. Copyright © 2017 Elsevier Inc. All rights reserved.

Peripheral Neuropathy and Agent Orange

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... Enter ZIP code here Enter ZIP code here Peripheral Neuropathy and Agent Orange VA presumes Veterans' early-onset ... 10 percent disabling by VA's rating regulations. About peripheral neuropathy Peripheral neuropathy is a condition of the peripheral ...

Detection of Toxoplasma gondii DNA in peripheral blood and aqueous humor of patients with Toxoplasmic active focal necrotizing retinochoroiditis using real-time PCR

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Fabio Felipe dos Santos

2015-12-01

Full Text Available ABSTRACT Purpose: To evaluate the ability of real-time quantitative PCR (qPCR for detectingToxoplasma gondii DNA in the peripheral blood and aqueous humor of patients with toxoplasmic active focal necrotizing retinochoroiditis. Methods: Fifty-five patients with infectious uveitis seen from 2009 to 2013 at the Department of Ophthalmology and Visual Sciences of the Federal University of São Paulo were enrolled in this study. Forty-three patients had toxoplasmic active focal necrotizing retinochoroiditis, and the remaining 12 had non-toxoplasmic infectious uveitis and served as controls. qPCR analysis forT. gondii DNA was performed on the patients' peripheral blood and aqueous humor samples. Results: The qPCR was positive for T. gondii DNA in 37.21% (16/43 of the aqueous humor samples and 2.33% (1/43 of the peripheral blood samples; further, 16.27% (7/43 of the patients had positive results in both their blood and aqueous humor samples. Conclusion: qPCR was able to detect T. gondii DNA in patients with toxoplasmic active focal necrotizing retinochoroiditis in the blood as well as the aqueous humor and can help with the diagnosis of the disease.

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity

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Künstler, E. C. S.; Finke, K.; Günther, A.; Klingner, C.; Witte, O.; Bublak, P.

2017-01-01

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the ‘theory of visual attention’ (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual sh...

Visual Performance of a Quadrifocal (Trifocal) Intraocular Lens Following Removal of the Crystalline Lens.

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Kohnen, Thomas; Herzog, Michael; Hemkeppler, Eva; Schönbrunn, Sabrina; De Lorenzo, Nina; Petermann, Kerstin; Böhm, Myriam

2017-12-01

To evaluate visual performance after implantation of a quadrifocal intraocular lens (IOL). Setting: Department of Ophthalmology, Goethe University, Frankfurt, Germany. Twenty-seven patients (54 eyes) received bilateral implantation of the PanOptix IOL (AcrySof IQ PanOptixTM; Alcon Research, Fort Worth, Texas, USA) pre-enrollment. Exclusion criteria were previous ocular surgeries, corneal astigmatism of >1.5 diopter (D), ocular pathologies, or corneal abnormalities. Intervention or Observational Procedure(s): Postoperative examination at 3 months including manifest refraction; uncorrected visual acuity (UCVA) and distance-corrected visual acuity (DCVA) in 4 m, 80 cm, 60 cm, and 40 cm slit-lamp examination; defocus testing; contrast sensitivity (CS) under photopic and mesopic conditions; and a questionnaire on subjective quality of vision, optical phenomena, and spectacle independence was performed. At 3 months postoperatively, UCVA and DCVA in 4 m, 80 cm, 60 cm, and 40 cm (logMAR), defocus curves, CS, and quality-of-vision questionnaire results. Mean spherical equivalent was -0.04 ± 0.321 D 3 months postoperatively. Binocular UCVA at distance, intermediate (80 cm, 60 cm), and near was 0.00 ± 0.094 logMAR, 0.09 ± 0.107 logMAR, 0.00 ± 0.111 logMAR, and 0.01 ± 0.087 logMAR, respectively. Binocular defocus curve showed peaks with best visual acuity (VA) at 0.00 D (-0.07 logMAR) and -2.00 D (-0.02 logMAR). Visual performance of the PanOptix IOL showed good VA at all distances; particularly good intermediate VA (logMAR > 0.1), with best VA at 60 cm; and high patient satisfaction and spectacle independence 3 months postoperatively. Copyright © 2017 Elsevier Inc. All rights reserved.

Time-Sharing-Based Synchronization and Performance Evaluation of Color-Independent Visual-MIMO Communication.

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Kwon, Tae-Ho; Kim, Jai-Eun; Kim, Ki-Doo

2018-05-14

In the field of communication, synchronization is always an important issue. The communication between a light-emitting diode (LED) array (LEA) and a camera is known as visual multiple-input multiple-output (MIMO), for which the data transmitter and receiver must be synchronized for seamless communication. In visual-MIMO, LEDs generally have a faster data rate than the camera. Hence, we propose an effective time-sharing-based synchronization technique with its color-independent characteristics providing the key to overcome this synchronization problem in visual-MIMO communication. We also evaluated the performance of our synchronization technique by varying the distance between the LEA and camera. A graphical analysis is also presented to compare the symbol error rate (SER) at different distances.

NEGOSIASI PENERJEMAHAN VERBAL - VISUAL DESAIN GRAFIS

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Moeljadi Pranata

2000-01-01

Full Text Available Design is commonly regarded as an act of individual creation to which both verbalization and logical analysis are only peripherally relevant. This article reviews a research study about talking design by Tomes et al (1998 which involving graphic designers and their clients. The conclusion is that talking design -- verbal and visual -- is the design itself. Comments from a design-major student give more light to the research s outputs. Abstract in Bahasa Indonesia : Desain umumnya dipandang sebagai karya ekspresi diri. Analisis logis dan penerjemahan verbal hanya dianggap relevan di permukaan saja. Artikel ini mereview kajian riset Tomes dkk. (1998 mengenai bahasan desain yang melibatkan tim desainer grafis dan kliennya. Simpulannya%2C bahasan desain ¾ verbal dan visual ¾ adalah desain itu sendiri. Artikel ini dilengkapi tanggapan mahasiswa desain terhadap hasil riset tersebut. graphic design%2C design process%2C verbal/visual communication

Attentional load modulates responses of human primary visual cortex to invisible stimuli.

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Bahrami, Bahador; Lavie, Nilli; Rees, Geraint

2007-03-20

Visual neuroscience has long sought to determine the extent to which stimulus-evoked activity in visual cortex depends on attention and awareness. Some influential theories of consciousness maintain that the allocation of attention is restricted to conscious representations [1, 2]. However, in the load theory of attention [3], competition between task-relevant and task-irrelevant stimuli for limited-capacity attention does not depend on conscious perception of the irrelevant stimuli. The critical test is whether the level of attentional load in a relevant task would determine unconscious neural processing of invisible stimuli. Human participants were scanned with high-field fMRI while they performed a foveal task of low or high attentional load. Irrelevant, invisible monocular stimuli were simultaneously presented peripherally and were continuously suppressed by a flashing mask in the other eye [4]. Attentional load in the foveal task strongly modulated retinotopic activity evoked in primary visual cortex (V1) by the invisible stimuli. Contrary to traditional views [1, 2, 5, 6], we found that availability of attentional capacity determines neural representations related to unconscious processing of continuously suppressed stimuli in human primary visual cortex. Spillover of attention to cortical representations of invisible stimuli (under low load) cannot be a sufficient condition for their awareness.

The Role of Global and Local Visual Information during Gaze-Cued Orienting of Attention.

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Munsters, Nicolette M; van den Boomen, Carlijn; Hooge, Ignace T C; Kemner, Chantal

2016-01-01

Gaze direction is an important social communication tool. Global and local visual information are known to play specific roles in processing socially relevant information from a face. The current study investigated whether global visual information has a primary role during gaze-cued orienting of attention and, as such, may influence quality of interaction. Adults performed a gaze-cueing task in which a centrally presented face cued (valid or invalid) the location of a peripheral target through a gaze shift. We measured brain activity (electroencephalography) towards the cue and target and behavioral responses (manual and saccadic reaction times) towards the target. The faces contained global (i.e. lower spatial frequencies), local (i.e. higher spatial frequencies), or a selection of both global and local (i.e. mid-band spatial frequencies) visual information. We found a gaze cue-validity effect (i.e. valid versus invalid), but no interaction effects with spatial frequency content. Furthermore, behavioral responses towards the target were in all cue conditions slower when lower spatial frequencies were not present in the gaze cue. These results suggest that whereas gaze-cued orienting of attention can be driven by both global and local visual information, global visual information determines the speed of behavioral responses towards other entities appearing in the surrounding of gaze cue stimuli.

Training of ultra-fast speech comprehension induces functional reorganization of the central-visual system in late-blind humans

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Susanne eDietrich

2013-10-01

Full Text Available Individuals suffering from vision loss of a peripheral origin may learn to understand spoken language at a rate of up to about 22 syllables (syl per seconds (s – exceeding by far the maximum performance level of untrained listeners (ca. 8 syl/s. Previous findings indicate the central-visual system to contribute to the processing of accelerated speech in blind subjects. As an extension, the present training study addresses the issue whether acquisition of ultra-fast (18 syl/s speech perception skills induces de novo central-visual hemodynamic activation in late-blind participants. Furthermore, we asked to what extent subjects with normal or residual vision can improve understanding of accelerated verbal utterances by means of specific training measures. To these ends, functional magnetic resonance imaging (fMRI was performed while subjects were listening to forward and reversed sentence utterances of moderately fast and ultra-fast syllable rates (8 or 18 syl/s prior to and after a training period of ca. six months. Four of six participants showed – independently from residual visual functions – considerable enhancement of ultra-fast speech perception (about 70 percentage points correctly repeated words whereas behavioral performance did not change in the two remaining participants. Only subjects with very low visual acuity displayed training-induced hemodynamic activation of the central-visual system. By contrast, participants with moderately impaired or even normal visual acuity showed, instead, increased right-hemispheric frontal or bilateral anterior temporal lobe responses after training. All subjects with significant training effects displayed a concomitant increase of hemodynamic activation of left-hemispheric SMA. In spite of similar behavioral performance, trained experts appear to use distinct strategies of ultra-fast speech processing depending on whether the occipital cortex is still deployed for visual processing.

Visual dysfunction, neurodegenerative diseases, and aging.

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Jackson, Gregory R; Owsley, Cynthia

2003-08-01

The four most common sight-threatening conditions in older adults in North America are cataract, ARM, glaucoma, and diabetic retinopathy. Even in their moderate stages, these conditions cause visual sensory impairments and reductions in health-related quality of life, including difficulties in daily tasks and psychosocial problems. Many older adults are free from these conditions, yet still experience a variety of visual perceptual problems resulting from aging-related changes in the optics of the eye and degeneration of the visual neural pathways. These problems consist of impairments in visual acuity, contrast sensitivity, color discrimination, temporal sensitivity, motion perception, peripheral visual field sensitivity, and visual processing speed. PD causes a progressive loss of dopaminergic cells predominantly in the retina and possibly in other areas of the visual system. This retinal dopamine deficiency produces selective spatial-temporal abnormalities in retinal ganglion cell function, probably arising from altered receptive field organization in the PD retina. The cortical degeneration characteristics of AD, including neurofibrillary tangles and neuritic plaques, also are present in the visual cortical areas, especially in the visual association areas. The most prominent electrophysiologic change in AD is a delay in the P2 component of the flash VEP. Deficits in higher-order visual abilities typically are compromised in AD, including problems with visual attention, perceiving structure from motion, visual memory, visual learning, reading, and object and face perception. There have been reports of a visual variant of AD in which these types of visual problems are the initial and most prominent signs of the disease. Visual sensory impairments (e.g., contrast sensitivity or achromatopsia) also have been reported but are believed more reflective of cortical disturbances than of AD-associated optic neuropathy.

Using the Freiburg Acuity and Contrast Test to measure visual performance in USAF personnel after PRK.

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Dennis, Richard J; Beer, Jeremy M A; Baldwin, J Bruce; Ivan, Douglas J; Lorusso, Frank J; Thompson, William T

2004-07-01

Photorefractive keratectomy (PRK) may be an alternative to spectacle and contact lens wear for United States Air Force (USAF) aircrew and may offer some distinct advantages in operational situations. However, any residual corneal haze or scar formation from PRK could exacerbate the disabling effects of a bright glare source on a complex visual task. The USAF recently completed a longitudinal clinical evaluation of the long-term effects of PRK on visual performance, including the experiment described herein. After baseline data were collected, 20 nonflying active duty USAF personnel underwent PRK. Visual performance was then measured at 6, 12, and 24 months after PRK. Visual acuity (VA) and contrast sensitivity (CS) data were collected by using the Freiburg Acuity and Contrast Test (FrACT), with the subject viewing half of the runs through a polycarbonate windscreen. Experimental runs were completed under 3 glare conditions: no glare source and with either a broadband or a green laser (532-nm) glare annulus (luminance approximately 6090 cd/m) surrounding the Landolt C stimulus. Systematic effects of PRK on VA relative to baseline were not identified. However, VA was almost 2 full Snellen lines worse with the laser glare source in place versus the broadband glare source. A significant drop-off was observed in CS performance after PRK under conditions of no glare and broadband glare; this was the case both with and without the windscreen. As with VA, laser glare disrupted CS performance significantly and more than broadband glare did. PRK does not appear to have affected VA, but the changes in CS might represent a true decline in visual performance. The greater disruptive effects from laser versus broadband glare may be a result of increased masking from coherent spatial noise (speckle) surrounding the laser stimulus.

Using a visual plate waste study to monitor menu performance.

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Connors, Priscilla L; Rozell, Sarah B

2004-01-01

Two visual plate waste studies were conducted in 1-week phases over a 1-year period in an acute care hospital. A total of 383 trays were evaluated in the first phase and 467 in the second. Food items were ranked for consumption from a low (1) to high (6) score, with a score of 4.0 set as the benchmark denoting a minimum level of acceptable consumption. In the first phase two entrees, four starches, all of the vegetables, sliced white bread, and skim milk scored below the benchmark. As a result six menu items were replaced and one was modified. In the second phase all entrees scored at or above 4.0, as did seven vegetables, and a dinner roll that replaced sliced white bread. Skim milk continued to score below the benchmark. A visual plate waste study assists in benchmarking performance, planning menu changes, and assessing effectiveness.

UV-blocking spectacle lens protects against UV-induced decline of visual performance.

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Liou, Jyh-Cheng; Teng, Mei-Ching; Tsai, Yun-Shan; Lin, En-Chieh; Chen, Bo-Yie

2015-01-01

Excessive exposure to sunlight may be a risk factor for ocular diseases and reduced visual performance. This study was designed to examine the ability of an ultraviolet (UV)-blocking spectacle lens to prevent visual acuity decline and ocular surface disorders in a mouse model of UVB-induced photokeratitis. Mice were divided into 4 groups (10 mice per group): (1) a blank control group (no exposure to UV radiation), (2) a UVB/no lens group (mice exposed to UVB rays, but without lens protection), (3) a UVB/UV400 group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [UV400 coating]), and (4) a UVB/photochromic group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [photochromic coating]). We investigated UVB-induced changes in visual acuity and in corneal smoothness, opacity, and lissamine green staining. We also evaluated the correlation between visual acuity decline and changes to the corneal surface parameters. Tissue sections were prepared and stained immunohistochemically to evaluate the structural integrity of the cornea and conjunctiva. In blank controls, the cornea remained undamaged, whereas in UVB-exposed mice, the corneal surface was disrupted; this disruption significantly correlated with a concomitant decline in visual acuity. Both the UVB/UV400 and UVB/photochromic groups had sharper visual acuity and a healthier corneal surface than the UVB/no lens group. Eyes in both protected groups also showed better corneal and conjunctival structural integrity than unprotected eyes. Furthermore, there were fewer apoptotic cells and less polymorphonuclear leukocyte infiltration in corneas protected by the spectacle lenses. The model established herein reliably determines the protective effect of UV-blocking ophthalmic biomaterials, because the in vivo protection against UV-induced ocular damage and visual acuity decline was easily defined.

Isolated effects of peripheral arm and central body cooling on arm performance.

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Giesbrecht, G G; Wu, M P; White, M D; Johnston, C E; Bristow, G K

1995-10-01

Whole body cooling impairs manual arm performance. The independent contributions of local (peripheral) and/or whole body (central) cooling are not known. Therefore, a protocol was developed in which the arm and the rest of the body could be independently cooled. Biceps temperature (Tmus), at a depth of 20 mm, and esophageal temperature (Tes) were measured. Six subjects were immersed to the clavicles in a tank (body tank) of water under 3 conditions: 1) cold body-cold arm (CB-CA); 2) warm body-cold arm (WB-CA); and 3) cold body-warm arm (CB-WA). In the latter two conditions, subjects placed their dominant arm in a separate (arm) tank. Water temperature (Tw) in each tank was independently controlled. In conditions requiring cold body and/or cold arm, Tw in the appropriate tanks was 8 degrees C. In conditions requiring warm body and/or warm arm, Tw in the appropriate tanks was adjusted between 29 and 38 degrees C to maintain body/arm temperature at baseline values. A battery of 6 tests, requiring fine or gross motor movements, were performed immediately before immersion and after 15, 45, and 70 minutes of immersion. In CB-CA, Tes decreased from an average of 37.2 to 35.6 degrees C and Tmus decreased from 34.6 to 22.0 degrees C. In WB-CA, Tmus decreased to 18.1 degrees C (Tes = 37.1 degrees C), and in CB-WA, Tes decreased to 35.8 degrees C (Tmus = 34.5 degrees C). By the end of immersion, there were significant decrements (43-85%) in the performance of all tests in CB-CA and WB-CA (p body and/or the arm elicits large decrements in finger, hand and arm performance. The decrements are due almost entirely to the local effects of arm tissue cooling.

[Impact of hypoglycemic episodes on nerves conduction and auditory and visual evoked potentials in children with type 1 diabetes].

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Wysocka-Mincewicz, Marta; Trippenbach-Dulska, Hanna; Emeryk-Szajewska, Barbara; Zakrzewska-Pniewska, Beata; Kochanek, Krzysztof; Pańkowska, Ewa

2007-01-01

Hypoglycemia is an acute disturbance of energy, especially impacting the central nervous system, but direct influence on peripheral nervous function is not detected. The aim of the study was to establish the influence of hypoglycemic moderate and severe episodes on the function of peripheral nerves, hearing and visual pathway. 97 children with type 1 diabetes (mean age 15.4+/-2.16 years, mean duration of diabetes 8.11+/-2.9 years, mean HbA1c 8,58+/-1.06%), at least 10 years old and with at least 3 years duration of diabetes, were included to study. Nerve conduction studies, visual (VEP) and auditory (ABR) evoked potentials were performed with standard surface stimulating and recording techniques. Moderate hypoglycemic episodes were defined as events of low glycemia requiring help of another person but without loss of consciousness and/or convulsions but recurrent frequently in at least one year. Severe hypoglycemia was defined as events with loss of consciousness and/or convulsions. Univariate ANOVA tests of significance or H Kruskal-Wallis test were used, depending on normality of distribution. The subgroups with a history of hypoglycemic episodes had significant delay in all conduction parameters in the sural nerve (amplitude pwave III latency and interval I-III in subgroups with episodes of hypoglycemia (pwave III and interval I-III. Frequent moderate hypoglycemic episodes were strong risk factors for damage of the peripheral and central nervous systems, comparable with impact of several severe hypoglycemias.

The impact of visual impairment on the ability to perform activities of daily living for persons with severe/profound intellectual disability.

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Dijkhuizen, Annemarie; Hilgenkamp, Thessa I M; Krijnen, Wim P; van der Schans, Cees P; Waninge, Aly

2016-01-01

The ability to perform activities of daily living (ADL) as a component of participation is one of the factors that contribute to quality of life. The ability to perform ADL for persons experiencing severe/profound intellectual disability (ID) may be reduced due to their cognitive and physical capacities. However, until recently, the impact of the significantly prevalent visual impairments on the performance of activities of daily living has not yet been revealed within this group. The purpose of this prospective cross-sectional study was to investigate the impact of visual impairment on the performance of activities of daily living for persons with a severe/profound intellectual disability. The Barthel Index (BI) and Comfortable Walking Speed (CWS) were used to measure the ability of performing activities of daily living (ADL) in 240 persons with severe/profound ID and having Gross Motor Functioning Classification System (GMFCS) levels I, II or III; this included 120 persons with visual impairment. The impact of visual impairment on ADL was analyzed with linear regression. The results of the study demonstrated that visual impairment slightly affects the ability of performing activities of daily living (BI) for persons experiencing a severe/profound intellectual disability. GMFCS Levels II or III, profound ID level, and visual impairment each have the effect of lowering BI scores. GMFCS Levels II or III, and profound ID level each have the effect of increasing CWS scores, which indicates a lower walking speed. A main effect of visual impairment is present on CWS, but our results do show a substantive interaction effect between GMFCS level III and visual impairment on Comfortable Walking Speed in persons with a severe/profound intellectual disability. Visual impairment has a slight effect on ability to perform ADL in persons experiencing severe/profound ID. Copyright © 2015 Elsevier Ltd. All rights reserved.

Peripheral regional anaesthesia and outcome: lessons learned from the last 10 years

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Kessler, J.; Marhofer, P.; Hopkins, P. M.; Hollmann, M. W.

2015-01-01

Our aim was to review the recent evidence for the efficacy of peripheral regional anaesthesia. Following a systematic literature search and selection of publications based on prospectively agreed upon criteria, we produced a narrative review of the most commonly performed peripheral regional

Organizational strategy influence on visual memory performance after stroke: cortical/subcortical and left/right hemisphere contrasts.

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Lange, G; Waked, W; Kirshblum, S; DeLuca, J

2000-01-01

To examine how organizational strategy at encoding influences visual memory performance in stroke patients. Case control study. Postacute rehabilitation hospital. Stroke patients with right hemisphere damage (n = 20) versus left hemisphere damage (n = 15), and stroke patients with cortical damage (n = 11) versus subcortical damage (n = 19). Organizational strategy scores, recall performance on the Rey-Osterrieth Complex Figure (ROCF). Results demonstrated significantly greater organizational impairment and less accurate copy performance (i.e., encoding of visuospatial information on the ROCF) in the right compared to the left hemisphere group, and in the cortical relative to the subcortical group. Organizational strategy and copy accuracy scores were significantly related to each other. The absolute amount of immediate and delayed recall was significantly associated with poor organizational strategy scores. However, relative to the amount of visual information originally encoded, memory performances did not differ between groups. These findings suggest that visual memory impairments after stroke may be caused by a lack of organizational strategy affecting information encoding, rather than an impairment in memory storage or retrieval.

Diffusion-weighted MRI in prostatic lesions: Diagnostic performance of normalized ADC using normal peripheral prostatic zone as a reference

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Tamer F. Taha Ali

2018-03-01

Full Text Available Aim of study: Evaluate the potential value of the normal peripheral zone as a reference organ to normalize prostatic lesion apparent diffusion coefficient (ADC to improve its evaluation of prostatic lesions. Patients and methods: This prospective study included 38 patients with clinical suspicion of cancer prostate (increased PSA levels (>4 ng/ml, hard prostate in digital rectal examination and who are scheduled to undergo a TRUS-guided biopsy. Conventional and DW-MRI was done and ADC was calculated. The normalized ADC value was calculated by dividing the ADC of lesion by ADC of reference site (healthy peripheral zone. DWI-MRI results were compared to the results of biopsy. Comparison of ADCs and nADCs of benign and malignant lesions was done. Receiver operating characteristics (ROC curve analysis was done. Results: The patients were classified by histopathology into non-malignant group (16 patients and malignant group (22 patients. Significant negative correlation between ADC and normalized ADC (nADC and malignancy was detected. There was no significant difference between the mean ADC of peripheral health prostatic zones (PZ between benign and malignant cases (2.221 ± 0.356 versus 1.99 ± 0.538x10−3 mm2/sec, p = 0.144.There was significant difference between the mean ADC and mean nADC in benign and malignant lesions (1.049 ± 0.217 versus 0.659 ± 0.221x10−3 mm2/sec, p < 0.001 and (0.475 ± 0.055 versus 0.328 ± 0.044, p < 0.001 respectively.There was significant higher diagnostic performance of nADC than ADC with ADC Cut-off value 0.75 × 10−3 mm2/sec and nADC cut-off value 0.39 could significantly differentiate between benign and malignant lesion with sensitivity, specificity, PPV,NPV of 86.36,75,82.61 and 80% respectively, p < 0.0001 for ADC and 95.45, 93.75, 95.45 and 93.75%, p < 0.0001 for nADC. Conclusion: diagnostic performance of nADC using normal peripheral zone is higher than

Spatial specificity of working memory representations in the early visual cortex.

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Pratte, Michael S; Tong, Frank

2014-03-19

Recent fMRI decoding studies have demonstrated that early retinotopic visual areas exhibit similar patterns of activity during the perception of a stimulus and during the maintenance of that stimulus in working memory. These findings provide support for the sensory recruitment hypothesis that the mechanisms underlying perception serve as a foundation for visual working memory. However, a recent study by Ester, Serences, and Awh (2009) found that the orientation of a peripheral grating maintained in working memory could be classified from both the contralateral and ipsilateral regions of the primary visual cortex (V1), implying that, unlike perception, feature-specific information was maintained in a nonretinotopic manner. Here, we evaluated the hypothesis that early visual areas can maintain information in a spatially specific manner and will do so if the task encourages the binding of feature information to a specific location. To encourage reliance on spatially specific memory, our experiment required observers to retain the orientations of two laterally presented gratings. Multivariate pattern analysis revealed that the orientation of each remembered grating was classified more accurately based on activity patterns in the contralateral than in the ipsilateral regions of V1 and V2. In contrast, higher extrastriate areas exhibited similar levels of performance across the two hemispheres. A time-resolved analysis further indicated that the retinotopic specificity of the working memory representation in V1 and V2 was maintained throughout the retention interval. Our results suggest that early visual areas provide a cortical basis for actively maintaining information about the features and locations of stimuli in visual working memory.

Peripheral neuropathy: an often-overlooked cause of falls in the elderly.

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Richardson, J K; Ashton-Miller, J A

1996-06-01

Peripheral neuropathy is common in the elderly and results in impairments in distal proprioception and strength that hinder balance and predispose them to falls. The loss of heel reflexes, decreased vibratory sense that improves proximally, impaired position sense at the great toe, and inability to maintain unipedal stance for 10 seconds in three attempts all suggest functionally significant peripheral neuropathy. Physicians can help their patients with peripheral neuropathy to prevent falls by teaching them and their families about peripheral nerve dysfunction and its effects on balance and by advising patients to substitute vision for the lost somatosensory function, correctly use a cane, wear proper shoes and orthotics, and perform balance and upper extremity strengthening exercises.

Macular Carotenoid Supplementation Improves Visual Performance, Sleep Quality, and Adverse Physical Symptoms in Those with High Screen Time Exposure.

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Stringham, James M; Stringham, Nicole T; O'Brien, Kevin J

2017-06-29

The dramatic rise in the use of smartphones, tablets, and laptop computers over the past decade has raised concerns about potentially deleterious health effects of increased "screen time" (ST) and associated short-wavelength (blue) light exposure. We determined baseline associations and effects of 6 months' supplementation with the macular carotenoids (MC) lutein, zeaxanthin, and mesozeaxanthin on the blue-absorbing macular pigment (MP) and measures of sleep quality, visual performance, and physical indicators of excessive ST. Forty-eight healthy young adults with at least 6 h of daily near-field ST exposure participated in this placebo-controlled trial. Visual performance measures included contrast sensitivity, critical flicker fusion, disability glare, and photostress recovery. Physical indicators of excessive screen time and sleep quality were assessed via questionnaire. MP optical density (MPOD) was assessed via heterochromatic flicker photometry. At baseline, MPOD was correlated significantly with all visual performance measures ( p eye strain, eye fatigue, and all visual performance measures, versus placebo ( p < 0.05 for all). Increased MPOD significantly improves visual performance and, in turn, improves several undesirable physical outcomes associated with excessive ST. The improvement in sleep quality was not directly related to increases in MPOD, and may be due to systemic reduction in oxidative stress and inflammation.

Evaluation and percutaneous management of atherosclerotic peripheral vascular disease

International Nuclear Information System (INIS)

Widlus, D.M.; Osterman, F.A. Jr.

1989-01-01

Atherosclerotic peripheral vascular disease (PVD) of the lower extremities deprives a person of the ability to exercise to their satisfaction, later of the ability to perform the activities of their daily life, and finally of their legs themselves. Peripheral vascular disease has long been managed by the vascular surgeon utilizing endarterectomy and peripheral arterial bypass. Patient acceptance of nonsurgical, percutaneous procedures such as percutaneous transluminal balloon angioplasty (PTA) is high. Increased utilization of these procedures has led to improved techniques and adjuncts to therapy, as well as more critical review of long-term results. This article will review the evaluation and nonoperative management of PVD, with an emphasis on the newer modalities of management presently being investigated

Associations between peripheral vertigo and gastroesophageal reflux disease.

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Viliušytė, Edita; Macaitytė, Raminta; Vaitkus, Antanas; Rastenytė, Daiva

2015-09-01

We hypothesize that peripheral vertigo is associated with gastroesophageal reflux disease (GERD). Two mechanisms could be considered – gastric acids may directly irritate the respiratory mucosa and cause inflammation, or Helicobacter pylori (H. pylori) could be present and cause local infection. Reflux material (Hydrochloric acid (HCl) and pepsin) could get into the middle ear via Eustachian tube and affect osseous structures directly. Disturbance of ossicles could cause tinnitus, which is more common for peripheral vertigo. H. pylori could also get in the esophagus and in the upper respiratory tract via gastroesophageal reflux, and could cause tympanosclerosis and fixation of ossicles. In our study group, 120 of 153 (78.4%) patients had gastroesophageal reflux disease (GERD). Diagnostic tests of H. pylori (rapid urease test or blood antibody test) were performed for 96 of 120 (80%) patients with GERD and were found positive for 32 of 96 (33.3%) patients. Peripheral vertigo was present in 93 of 120 (77.6%) patients with GERD compared to 33 of 126 (26%) patients without GERD (χ(2)=9.016, p=0.003). H. pylori and peripheral vertigo coexisted in 26 of 126 patients (20.6%) (OR 1.36; 95% CI 0.49-3.74, p=0.55). Our study demonstrated statistically significant association between peripheral vertigo and GERD but not between peripheral vertigo and H. pylori. Further more extensive investigations are needed in order to explore our hypothesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Critical care nurses' experiences of performing successful peripheral intravenous catheterization in difficult situations.

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Forsberg, Angelica; Engström, Åsa

2018-06-01

The aim of this study is to describe the experiences of critical care nurses (CCNs) when performing successful peripheral intravenous catheterization (PIVC) on adult inpatients in difficult situations. This study uses a descriptive design with a qualitative approach. Semistructured interviews were given to CCNs (n = 22) at a general central county hospital in northern Sweden. The interview text was analyzed with qualitative thematic content analysis. Three themes emerged: "releasing time and creating peace," "feeling self-confidence in the role of expert nurse," and "technical interventions promoting success." CCNs stated that apart from experience, releasing enough time is the most crucial factor for a successful PIVC. They emphasized the importance of identifying the kinds of difficulties that may occur during the procedure, for example, fragile or/and invisible veins. CCNs explained that compared to when they were newly graduated, the difference in their approach nowadays has changed to using their hands more than their eyes and that they feel comfortable with bodily palpations. To further optimize PIVC performing skills, continued possibilities to train and learn in hospital settings are necessary, even after formal education has been completed. Copyright © 2018 Society for Vascular Nursing, Inc. Published by Elsevier Inc. All rights reserved.

Functional evaluation of peripheral nerve regeneration in the rat : walking track analysis

NARCIS (Netherlands)

Varejao, ASP; Meek, MF; Patricio, JAB; Cabrita, AMS

2001-01-01

The experimental model of choice for many peripheral nerve investigators is the rat. Walking track analysis is a useful tool in the evaluation of functional peripheral nerve recovery in the rat. This quantitative method of analyzing hind limbs performance by examining footprints, known as the

Drug-induced peripheral neuropathy

DEFF Research Database (Denmark)

Vilholm, Ole Jakob; Christensen, Alex Alban; Zedan, Ahmed

2014-01-01

Peripheral neuropathy can be caused by medication, and various descriptions have been applied for this condition. In this MiniReview, the term 'drug-induced peripheral neuropathy' (DIPN) is used with the suggested definition: Damage to nerves of the peripheral nervous system caused by a chemical...... substance used in the treatment, cure, prevention or diagnosis of a disease. Optic neuropathy is included in this definition. A distinction between DIPN and other aetiologies of peripheral neuropathy is often quite difficult and thus, the aim of this MiniReview is to discuss the major agents associated...

Simulator Evaluation of Drivers’ Performance on Rural Highways in relation to Drivers’ Visual Attention Demands

Directory of Open Access Journals (Sweden)

Yaqin Qin

2015-01-01

Full Text Available Aim of the study is to investigate, by means of a driving simulator experiment, drivers’ performance in terms of lateral position, speed, deceleration, steering angle, and breaking times on a divided two-lane rural highway in relation to drivers’ visual attention (VD. In the experiment, the virtual scene of twenty different geometric alignment sections without traffic and the VD testing were designed. Twenty-three experienced drivers with the calibration of attention capacity participated in a 30 km drive in an interactive fixed-base simulator. Each participant was required to drive with the controlled speed of 60 km/h along the central lane as repeating random number and was evaluated on VD and driving performances. Three different data analysis techniques were used: (a statistical tests and hypothesis test of curvature change rate (CCR of the geometric alignments, visual attention demands, and driving performance data, (b correlation analysis of VD, CCRs, and driving behaviors, and (c regression analysis of the VD and CCRs. Results have showed that the driving performance can be effectively influenced by the highway alignment and a prediction model built in this study can evaluate the drivers’ visual attention demands before the highway constructed. The interactions among VD, driving behavior, and CCRs were also found.

Processing of unattended facial emotions: a visual mismatch negativity study.

Science.gov (United States)

Stefanics, Gábor; Csukly, Gábor; Komlósi, Sarolta; Czobor, Pál; Czigler, István

2012-02-01

Facial emotions express our internal states and are fundamental in social interactions. Here we explore whether the repetition of unattended facial emotions builds up a predictive representation of frequently encountered emotions in the visual system. Participants (n=24) were presented peripherally with facial stimuli expressing emotions while they performed a visual detection task presented in the center of the visual field. Facial stimuli consisted of four faces of different identity, but expressed the same emotion (happy or fearful). Facial stimuli were presented in blocks of oddball sequence (standard emotion: p=0.9, deviant emotion: p=0.1). Event-related potentials (ERPs) to the same emotions were compared when the emotions were deviant and standard, respectively. We found visual mismatch negativity (vMMN) responses to unattended deviant emotions in the 170-360 ms post-stimulus range over bilateral occipito-temporal sites. Our results demonstrate that information about the emotional content of unattended faces presented at the periphery of the visual field is rapidly processed and stored in a predictive memory representation by the visual system. We also found evidence that differential processing of deviant fearful faces starts already at 70-120 ms after stimulus onset. This finding shows a 'negativity bias' under unattended conditions. Differential processing of fearful deviants were more pronounced in the right hemisphere in the 195-275 ms and 360-390 ms intervals, whereas processing of happy deviants evoked larger differential response in the left hemisphere in the 360-390 ms range, indicating differential hemispheric specialization for automatic processing of positive and negative affect. Copyright © 2011 Elsevier Inc. All rights reserved.

Systematic Review of Guidelines on Peripheral Artery Disease Screening

NARCIS (Netherlands)

Ferket, Bart S.; Spronk, Sandra; Colkesen, Ersen B.; Hunink, M. G. Myriam

2012-01-01

BACKGROUND: Peripheral artery disease (PAD) screening may be performed to prevent progression of PAD or future cardiovascular disease in general. Recommendations for PAD screening have to be derived indirectly because no randomized trials comparing screening versus no screening have been performed.

Peripheral neuropathy is associated with more frequent falls in Parkinson's disease.

Science.gov (United States)

Beaulieu, Mélanie L; Müller, Martijn L T M; Bohnen, Nicolaas I

2018-04-03

Peripheral neuropathy is a common condition in the elderly that can affect balance and gait. Postural imbalance and gait difficulties in Parkinson's disease (PD), therefore, may stem not only from the primary neurodegenerative process but also from age-related medical comorbidities. Elucidation of the effects of peripheral neuropathy on these difficulties in PD is important to provide more targeted and effective therapy. The purpose of this study was to investigate the association between lower-limb peripheral neuropathy and falls and gait performance in PD while accounting for disease-specific factors. From a total of 140 individuals with PD, 14 male participants met the criteria for peripheral neuropathy and were matched 1:1 for Hoehn & Yahr stage and duration of disease with 14 male participants without peripheral neuropathy. All participants underwent fall (retrospectively) and gait assessment, a clinical evaluation, and [ 11 C]dihydrotetrabenazine and [ 11 C]methylpiperidin-4-yl propionate PET imaging to assess dopaminergic and cholinergic denervation, respectively. The presence of peripheral neuropathy was significantly associated with more falls (50% vs. 14%, p = 0.043), as well as a shorter stride length (p = 0.011) and greater stride length variability (p = 0.004), which resulted in slower gait speed (p = 0.016) during level walking. There was no significant difference in nigrostriatal dopaminergic denervation, cortical and thalamic cholinergic denervation, and MDS-UPDRS motor examination scores between groups. Lower-limb peripheral neuropathy is significantly associated with more falls and gait difficulties in PD. Thus, treating such neuropathy may reduce falls and/or improve gait performance in PD. Copyright © 2018 Elsevier Ltd. All rights reserved.

NEGOSIASI PENERJEMAHAN VERBAL - VISUAL DESAIN GRAFIS

OpenAIRE

Moeljadi Pranata

2000-01-01

Design is commonly regarded as an act of individual creation to which both verbalization and logical analysis are only peripherally relevant. This article reviews a research study about talking design by Tomes et al (1998) which involving graphic designers and their clients. The conclusion is that talking design -- verbal and visual -- is the design itself. Comments from a design-major student give more light to the research s outputs. Abstract in Bahasa Indonesia : Desain umumnya dipandang s...

VRP09 Objective Methods to Test Visual Dysfunction in the Presence of Cognitive Impairment

Science.gov (United States)

2014-10-01

cortex  in response  to  visual  stimuli  in  the  central  and  peripheral...defined  damage  to  the  retina,  optic  nerve,  visual   radiations  or  visual   cortex  will  be  used  to  study...tooth  to  the  portable   processor  or  also  to  a  nearby  computer.   The  optical  head  can  be

Visual performance in cataract patients with low levels of postoperative astigmatism: full correction versus spherical equivalent correction

Directory of Open Access Journals (Sweden)

Lehmann RP

2012-03-01

Full Text Available Robert P Lehmann1, Diane M Houtman21Lehmann Eye Center, Nacogdoches, TX, 2Alcon Research Ltd, Fort Worth, TX, USAPurpose: To evaluate whether visual performance could be improved in pseudophakic subjects by correcting low levels of postoperative astigmatism.Methods: An exploratory, noninterventional study was conducted using subjects who had been implanted with an aspheric intraocular lens and had 0.5–0.75 diopter postoperative astigmatism. Monocular visual performance using full correction was compared with visual performance using spherical equivalent correction. Testing consisted of high- and low-contrast visual acuity, contrast sensitivity, and reading acuity and speed using the Radner Reading Charts.Results: Thirty-eight of 40 subjects completed testing. Visual acuities at three contrast levels (100%, 25%, and 9% were significantly better using full correction than when using spherical equivalent correction (all P < 0.001. For contrast sensitivity testing under photopic, mesopic, and mesopic with glare conditions, only one out of twelve outcomes demonstrated a significant improvement with full correction compared with spherical equivalent correction (at six cycles per degree under mesopic without glare conditions, P = 0.046. Mean reading speed was numerically faster with full correction across all print sizes, reaching statistical significance at logarithm of the reading acuity determination (logRAD 0.2, 0.7, and 1.1 (P , 0.05. Statistically significant differences also favored full correction in logRAD score (P = 0.0376, corrected maximum reading speed (P < 0.001, and logarithm of the minimum angle of resolution/logRAD ratio (P < 0.001.Conclusions: In this study of pseudophakic subjects with low levels of postoperative astigmatism, full correction yielded significantly better reading performance and high- and low-contrast visual acuity than spherical equivalent correction, suggesting that cataractous patients may benefit from surgical

Peripheral pulmonary arteries: identification at multi-slice spiral CT with 3D reconstruction

International Nuclear Information System (INIS)

Coche, Emmanuel; Pawlak, Sebastien; Dechambre, Stephane; Maldague, Baudouin

2003-01-01

Our objective was to analyze the peripheral pulmonary arteries using thin-collimation multi-slice spiral CT. Twenty consecutive patients underwent enhanced-spiral multi-slice CT using 1-mm collimation. Two observers analyzed the pulmonary arteries by consensus on a workstation. Each artery was identified on axial and 3D shaded-surface display reconstruction images. Each subsegmental artery was measured at a mediastinal window setting and compared with anatomical classifications. The location and branching of every subsegmental artery was recorded. The number of well-visualized sub-subsegmental arteries at a mediastinal window setting was compared with those visualized at a lung window setting. Of 800 subsegmental arteries, 769 (96%) were correctly visualized and 123 accessory subsegmental arteries were identified using the mediastinal window setting. One thousand ninety-two of 2019 sub-subsegmental arteries (54%) identified using the lung window setting were correctly visualized using the mediastinal window setting. Enhanced multi-slice spiral CT with thin collimation can be used to analyze precisely the subsegmental pulmonary arteries and may identify even more distal pulmonary arteries. (orig.)

The influence of assistive technology devices on the performance of activities by visually impaired

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Suzana Rabello

2014-04-01

Full Text Available Objective: To establish the influence of assistive technology devices (ATDs on the performance of activities by visually impaired schoolchildren in the resource room. Methods: A qualitative study that comprised observation and an educational intervention in the resource room. The study population comprised six visually impaired schoolchildren aged 12 to 14 years old. The participants were subjected to an eye examination, prescribed ATDs comprising optical and non-optical devices, and provided an orientation on the use of computers. The participants were assessed based on eye/object distance, font size, and time to read a computer screen and printed text. Results: The ophthalmological conditions included corneal opacity, retinochoroiditis, retinopathy of prematurity, aniridia, and congenital cataracts. Far visual acuity varied from 20/200 to 20/800 and near visual acuity from 0.8 to 6 M. Telescopes, spherical lenses, and support magnifying glasses were prescribed. Three out of five participants with low vision after intervention could decrease the font size on the screen computer, and most participants (83.3% reduced their reading time at the second observation session. Relative to the printed text, all the participants with low vision were able to read text written in smaller font sizes and reduced their reading time at the second observation session. Conclusion: Reading skills improved after the use of ATDs, which allowed the participants to perform their school tasks equally to their classmates.

Visual inspection equipment for the secondary side of steam generators. Final report

International Nuclear Information System (INIS)

Hinton, M.S.; Chagnon, C.W.

1981-05-01

The development of miniature visual examination equipment capable of inspecting regions inside the tube bundles of nuclear steam generators to determine such factors as gap condition, tube outside surface condition, and material buildup is described. Tube-to-support plate interface regions at the tenth-support plate level in a once-through steam generator (Oconee 1) were visually examined. Other areas in the peripheral region were examined for conditions associated with available eddy-current and profilometer data

[Diagnostic performance of T-SPOT.TB on peripheral blood in combination with adenosine deaminase on pleural fluid for the diagnosis of tuberculous pleurisy within different age group].

Science.gov (United States)

Xu, H Y; Zhang, D Q; Ye, J R; Su, S S; Xie, Y P; Chen, C S; Li, Y P

2017-06-27

Objective: To evaluate the performance of T cell enzyme-linked immuno-spot assay (T-SPOT) on peripheral blood in combination with adenosine deaminase (ADA) on pleural fluid for diagnosis of tuberculous (TB) pleurisy within different age groups. Methods: The data of patients with pleural effusion from the Department of Pulmonary and Critical Care Medicine of the First Affiliated Hospital of Wenzhou Medical University from April 2012 to November 2016 were retrospectively analyzed, and the diagnoses of these patients were histopathologically confirmed through medical thoracoscopy. The cases who had confirmed diagnosis, in the same time, received peripheral blood T-SPOT.TB were enrolled. The performance of peripheral blood T-SPOT.TB in combination with pleural fluid ADA on diagnosing TB pleurisy in the younger patients (16-59 years old) and elderly patients (≥60 years old) were analyzed respectively. The sensitivity, specificity and the receiver operating characteristic (ROC) curve were adopted for statistical analysis. Results: A total of 448 cases were finally enrolled, 341(76.1%) confirmed with TB pleurisy, 224 males, 117 females, (47±19) years old; and 107 (23.9%) classified as non-TB pleurisy, 65 males, 42 females, (61±14) years old. There were 285 cases who were classified as younger group, and the other 163 cases were classified as elderly group. The sensitivity and specificity of peripheral blood T-SPOT.TB were 85.4% (204/239) and 71.7% (33/46) in the younger patients, 76.5% (78/102) and 59.0% (36/61) respectively in the elderly patients. The sensitivity of peripheral blood T-SPOT.TB in the younger patients was significantly higher than that in the elderly patients ( P =0.047). The sensitivity and specificity were 99.2% and 95.7% in combination with peripheral blood T-SPOT.TB and pleural fluid ADA respectively in the younger patients. The area under ROC curve (AUC) of T-SPOT.TB in the younger patients was 0.833, AUC of T-SPOT.TB combined with ADA was 0

Visual search performance in infants associates with later ASD diagnosis.

Science.gov (United States)

Cheung, C H M; Bedford, R; Johnson, M H; Charman, T; Gliga, T

2018-01-01

An enhanced ability to detect visual targets amongst distractors, known as visual search (VS), has often been documented in Autism Spectrum Disorders (ASD). Yet, it is unclear when this behaviour emerges in development and if it is specific to ASD. We followed up infants at high and low familial risk for ASD to investigate how early VS abilities links to later ASD diagnosis, the potential underlying mechanisms of this association and the specificity of superior VS to ASD. Clinical diagnosis of ASD as well as dimensional measures of ASD, attention-deficit/hyperactivity disorder (ADHD) and anxiety symptoms were ascertained at 3 years. At 9 and 15 months, but not at age 2 years, high-risk children who later met clinical criteria for ASD (HR-ASD) had better VS performance than those without later diagnosis and low-risk controls. Although HR-ASD children were also more attentive to the task at 9 months, this did not explain search performance. Superior VS specifically predicted 3 year-old ASD but not ADHD or anxiety symptoms. Our results demonstrate that atypical perception and core ASD symptoms of social interaction and communication are closely and selectively associated during early development, and suggest causal links between perceptual and social features of ASD. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

The Effects of an Auditory Versus a Visual Presentation of Information on Soldier Performance

National Research Council Canada - National Science Library

Glumm, Monica

1999-01-01

This report describes a field study designed to measure the effects of an auditory versus a visual presentation of position information on soldier performance of land navigation and target acquisition tasks...

Peripheral cold acclimatization in Antarctic scuba divers.

Science.gov (United States)

Bridgman, S A

1991-08-01

Peripheral acclimatization to cold in scuba divers stationed at the British Antarctic Survey's Signy Station was investigated during a year in Antarctica. Five divers and five non-diver controls underwent monthly laboratory tests of index finger immersion in cold water for 30 min. Index finger pulp temperature and time of onset of cold-induced vasodilatation (CIVD) were measured. Pain was recorded with verbal and numerical psychophysical subjective pain ratings. Average finger temperatures and median finger pain from 6-30 min of immersion, maximum finger temperatures during the first CIVD cycle, and finger temperatures at the onset of CIVD were calculated. Comparison of the variables recorded from divers and non-divers were performed with analysis of variance. No significant differences were found among the variables recorded from divers and non-divers. From a review of the literature, divers have responses typical of non-cold-adapted Caucasians. There is, therefore, no evidence that Signy divers peripherally acclimatized to cold. We suggest that these findings occur because either the whole body cooling which divers undergo inhibits peripheral acclimatization or because of insufficiently frequent or severe cold exposure while diving. Further basic studies on the duration, frequency and severity of cold exposure necessary to induce peripheral cold acclimatization are required before this question can be satisfactorily answered.

Visual function affects prosocial behaviors in older adults.

Science.gov (United States)

Teoli, Dac A; Smith, Merideth D; Leys, Monique J; Jain, Priyanka; Odom, J Vernon

2016-02-01

Eye-related pathological conditions such as glaucoma, diabetic retinopathy, and age-related macular degeneration commonly lead to decreased peripheral/central field, decreased visual acuity, and increased functional disability. We sought to answer if relationships exist between measures of visual function and reported prosocial behaviors in an older adult population with eye-related diagnoses. The sample consisted of adults, aged ≥ 60 years old, at an academic hospital's eye institute. Vision ranged from normal to severe impairment. Medical charts determined the visual acuities, ocular disease, duration of disease (DD), and visual fields (VF). Measures of giving help were via validated questionnaires on giving formal support (GFS) and giving informal support; measures of help received were perceived support (PS) and informal support received (ISR). ISR had subscales: tangible support (ISR-T), emotional support (ISR-E), and composite (ISR-C). Visual acuities of the better and worse seeing eyes were converted to LogMAR values. VF information converted to a 4-point rating scale of binocular field loss severity. DD was in years. Among 96 participants (mean age 73.28; range 60-94), stepwise regression indicated a relationship of visual variables to GFS (p T (p prosocial behavior in older adults.

Propylthiouracil and peripheral neuropathy

Directory of Open Access Journals (Sweden)

Valentina Van Boekel

1992-06-01

Full Text Available Peripheral neuropathy is a rare manifestation in hyperthyroidism. We describe the neurological manifestations of a 38 year old female with Graves' disease who developed peripheral neuropathy in the course of her treatment with propylthiouracil. After the drug was tapered off, the neurological signs disappeared. Therefore, we call attention for a possible toxic effect on peripheral nervous system caused by this drug.

Sonographic identification of peripheral nerves in the forearm

Directory of Open Access Journals (Sweden)

Saundra A Jackson

2016-01-01

Full Text Available Background: With the growing utilization of ultrasonography in emergency medicine combined with the concern over adequate pain management in the emergency department (ED, ultrasound guidance for peripheral nerve blockade in ED is an area of increasing interest. The medical literature has multiple reports supporting the use of ultrasound guidance in peripheral nerve blocks. However, to perform a peripheral nerve block, one must first be able to reliably identify the specific nerve before the procedure. Objective: The primary purpose of this study is to describe the number of supervised peripheral nerve examinations that are necessary for an emergency medicine physician to gain proficiency in accurately locating and identifying the median, radial, and ulnar nerves of the forearm via ultrasound. Methods: The proficiency outcome was defined as the number of attempts before a resident is able to correctly locate and identify the nerves on ten consecutive examinations. Didactic education was provided via a 1 h lecture on forearm anatomy, sonographic technique, and identification of the nerves. Participants also received two supervised hands-on examinations for each nerve. Count data are summarized using percentages or medians and range. Random effects negative binomial regression was used for modeling panel count data. Results: Complete data for the number of attempts, gender, and postgraduate year (PGY training year were available for 38 residents. Nineteen males and 19 females performed examinations. The median PGY year in practice was 3 (range 1-3, with 10 (27% in year 1, 8 (22% in year 2, and 19 (51% in year 3 or beyond. The median number (range of required supervised attempts for radial, median, and ulnar nerves was 1 (0-12, 0 (0-10, and 0 (0-17, respectively. Conclusion: We can conclude that the maximum number of supervised attempts to achieve accurate nerve identification was 17 (ulnar, 12 (radial, and 10 (median in our study. The only

Cholinergic control of visual categorisation in macaques

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Nikolaos C. Aggelopoulos

2011-11-01

Full Text Available Acetylcholine (ACh is a neurotransmitter acting via muscarinic and nicotinic receptors that is implicated in several cognitive functions and impairments, such as Alzheimer’s disease. It is believed to especially affect the acquisition of new information, which is particularly important when behaviour needs to be adapted to new situations and to novel sensory events. Categorisation, the process of assigning stimuli to a category, is a cognitive function that also involves information acquisition. The role of ACh on categorisation has not been previously studied. We have examined the effects of scopolamine, an antagonist of muscarinic ACh receptors, on visual categorisation in macaque monkeys using familiar and novel stimuli. When the peripheral effects of scopolamine on the parasympathetic nervous system were controlled for, categorisation performance was disrupted following systemic injections of scopolamine. This impairment was observed only when the stimuli that needed to be categorised had not been seen before. In other words, the monkeys were not impaired by the central action of scopolamine in categorising a set of familiar stimuli (stimuli which they had categorised successfully in previous sessions. Categorisation performance also deteriorated as the stimulus became less salient by an increase in the level of visual noise. However, scopolamine did not cause additional performance disruptions for difficult categorisation judgements at lower coherence levels. Scopolamine, therefore, specifically affects the assignment of new exemplars to established cognitive categories, presumably by impairing the processing of novel information. Since we did not find an effect of scopolamine in the categorisation of familiar stimuli, scopolamine had no significant central action on other cognitive functions such as perception, attention, memory or executive control within the context of our categorisation task.

VISUAL PERCEPTION OF THE CHILDREN WITH PLEXUS BRACHIALIS DAMAGE – ASSESSMENT AND TREATMENT

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Dragana M. KLJAJIKJ

2012-03-01

Full Text Available Interpersonal communication, psychosocial and mental development of personality and its all other functions take place through the motor control. The most common neurological syndrome is a type of peripheral paresis/paralysis of plexus bracialis, which in most cases occurs at birth and significantly compromises the growth and development of the upper extremities and affects the psychomotor performance. The aim of this study was to evaluate the level of visual perception in children with lesion of plexus brachialis and the effect of the somatopedic treatment over the level of increase of the visual perception. The study sample was consisted of 60 preschool children accommodated at the Rehabilitation Centre “Dr. Miroslav Zotović” in Belgrade (experimental group and examiners that followed regular checkups and had discontinuity in their therapy (control group. For the research purposes, we used The Test for Visual Perception Assessment. By analyzing the results, we concluded that in both, in the first and the second measuring there was a statistically significant correlation between the experimental and the control groups (I measuring: p<0.001, r = 0.408; II measuring: p <0.001, r = 0.593.

Stress Induction and Visual Working Memory Performance: The Effects of Emotional and Non-Emotional Stimuli

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Zahra Khayyer

2017-05-01

Full Text Available Background Some studies have shown working memory impairment following stressful situations. Also, researchers have found that working memory performance depends on many different factors such as emotional load of stimuli and gender. Objectives The present study aimed to determine the effects of stress induction on visual working memory (VWM performance among female and male university students. Methods This quasi-experimental research employed a posttest with only control group design (within-group study. A total of 62 university students (32 males and 30 females were randomly selected and allocated to experimental and control groups (mean age of 23.73. Using cold presser test (CPT, stress was induced and then, an n-back task was implemented to evaluate visual working memory function (such as the number of true items, time reactions, and the number of wrong items through emotional and non-emotional pictures. 100 pictures were selected from the international affective picture system (IASP with different valences. Results Results showed that stress impaired different visual working memory functions (P < 0.002 for true scores, P < 0.001 for reaction time, and P < 0.002 for wrong items. Conclusions In general, stress significantly decreases the VWM performances. On the one hand, females were strongly impressed by stress more than males and on the other hand, the VWM performance was better for emotional stimuli than non-emotional stimuli.

Peripheral Neuropathy: Symptoms and Signs

Science.gov (United States)

... Utah Research News Make a Difference Symptoms of Peripheral Neuropathy Print This Page Peripheral Neuropathy symptoms usually start ... more slowly over many years. The symptoms of peripheral neuropathy often include: A sensation of wearing an invisible “ ...

A low complexity visualization tool that helps to perform complex systems analysis

International Nuclear Information System (INIS)

Beiro, M G; Alvarez-Hamelin, J I; Busch, J R

2008-01-01

In this paper, we present an extension of large network visualization (LaNet-vi), a tool to visualize large scale networks using the k-core decomposition. One of the new features is how vertices compute their angular position. While in the later version it is done using shell clusters, in this version we use the angular coordinate of vertices in higher k-shells, and arrange the highest shell according to a cliques decomposition. The time complexity goes from O(n√n) to O(n) upon bounds on a heavy-tailed degree distribution. The tool also performs a k-core-connectivity analysis, highlighting vertices that are not k-connected; e.g. this property is useful to measure robustness or quality of service (QoS) capabilities in communication networks. Finally, the actual version of LaNet-vi can draw labels and all the edges using transparencies, yielding an accurate visualization. Based on the obtained figure, it is possible to distinguish different sources and types of complex networks at a glance, in a sort of 'network iris-print'.

A low complexity visualization tool that helps to perform complex systems analysis

Science.gov (United States)

Beiró, M. G.; Alvarez-Hamelin, J. I.; Busch, J. R.

2008-12-01

In this paper, we present an extension of large network visualization (LaNet-vi), a tool to visualize large scale networks using the k-core decomposition. One of the new features is how vertices compute their angular position. While in the later version it is done using shell clusters, in this version we use the angular coordinate of vertices in higher k-shells, and arrange the highest shell according to a cliques decomposition. The time complexity goes from O(n\\sqrt n) to O(n) upon bounds on a heavy-tailed degree distribution. The tool also performs a k-core-connectivity analysis, highlighting vertices that are not k-connected; e.g. this property is useful to measure robustness or quality of service (QoS) capabilities in communication networks. Finally, the actual version of LaNet-vi can draw labels and all the edges using transparencies, yielding an accurate visualization. Based on the obtained figure, it is possible to distinguish different sources and types of complex networks at a glance, in a sort of 'network iris-print'.

Audio-Visual Speech Recognition Using MPEG-4 Compliant Visual Features

Directory of Open Access Journals (Sweden)

Petar S. Aleksic

2002-11-01

Full Text Available We describe an audio-visual automatic continuous speech recognition system, which significantly improves speech recognition performance over a wide range of acoustic noise levels, as well as under clean audio conditions. The system utilizes facial animation parameters (FAPs supported by the MPEG-4 standard for the visual representation of speech. We also describe a robust and automatic algorithm we have developed to extract FAPs from visual data, which does not require hand labeling or extensive training procedures. The principal component analysis (PCA was performed on the FAPs in order to decrease the dimensionality of the visual feature vectors, and the derived projection weights were used as visual features in the audio-visual automatic speech recognition (ASR experiments. Both single-stream and multistream hidden Markov models (HMMs were used to model the ASR system, integrate audio and visual information, and perform a relatively large vocabulary (approximately 1000 words speech recognition experiments. The experiments performed use clean audio data and audio data corrupted by stationary white Gaussian noise at various SNRs. The proposed system reduces the word error rate (WER by 20% to 23% relatively to audio-only speech recognition WERs, at various SNRs (0–30 dB with additive white Gaussian noise, and by 19% relatively to audio-only speech recognition WER under clean audio conditions.

Language, visuality, and the body. On the return of discourse in contemporary performance

Directory of Open Access Journals (Sweden)

Vangelis Athanassopoulos

2013-12-01

Full Text Available This article deals with the return of discourse in experimental performance-based artistic practices. By putting this return in a historical perspective, we wish to address the questions it raises on the relation between language, image, and the body, resituating the avant-garde heritage in a contemporary context where intermediality and transdisciplinarity tend to become the norm rather than the exception. The discussion of the status and function of discourse in this context calls on the field of theatre and its ambivalent role in modern aesthetics, both as a specifically determined artistic discipline, and as a blending of heterogeneous elements, which defy the assigned limitations of creative practice. The confrontation of Antonin Artaud's writings with Michael Fried's conception of theatricality aims to bring to the fore the cultural transformations and historical paradoxes which inform the shift from theatre to performance as an experimental field situated “between” the arts and embracing a wide range of practices, from visual arts to music and dance. The case of lecture-performance enables us to call attention to the internal contradictions of the “educational” interpretation of such experimental practices and their autonomization inside the limits of a specific artistic genre. The main argument is that, despite the plurality of its origins and its claims to intermediality and transdisciplinarity, lecture-performance as a genre is attracted by or gravitates around the extended field of the visual arts. By focusing on the work of Jerôme Bel, Noé Soulier, Giuseppe Chico, Barbara Matijevic, and Carole Douillard, we stress some of the ways contemporary discursive strategies enable to displace visual spectacle toward a conception of the body as the limit of signification.

Is clinical performance adversely affected by wearing gloves during paediatric peripheral intravenous cannulation?

Science.gov (United States)

Zhang, Michael; Lee, Mark; Knott, Susan

2014-10-01

To investigate if wearing protective gloves during paediatric intravenous cannulation affects performance of the procedure. This was a prospective observational study. Peripheral intravenous cannulation (PIVC) performed within the Paediatric ED was observed and recorded over a 12 month period. Data were compared between those clinicians wearing gloves and those not wearing gloves during PIVC. One thousand and twenty paediatric cannulations were recorded during the observed period. The mean age of the children was 5.79 years. The overall success rate of cannulation was 86.18% and first attempt success rate 76.08%. Overall, gloves were used by 54.31% of clinicians to establish vascular access; glove use was lowest in the registrar group (41.11% compliance rate). The glove-wearing group had comparable overall success rate of 85.74% (475/554) to the no-gloves group of 86.70% (404/466). The difference was not statistically significant (P > 0.05). Higher incidence of significant blood spillage during the procedure was observed among clinicians wearing no gloves (16.74%) in comparison with their glove-wearing counterparts (9.03%, P glove-wearing group and no-gloves group (3.94% vs 3.76%, P > 0.05). The present study shows that the use of protective gloves was not associated with adverse outcomes of clinical performance during paediatric cannulation. The low compliance rate of gloves use is alarming, and many clinicians might be exposed to potential blood-borne infections. Clinicians should be encouraged and supported to use gloves for paediatric cannulation. © 2014 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Registry Assessment of Peripheral Interventional Devices (RAPID)　- Registry Assessment of Peripheral Interventional Devices Core Data Elements.

Science.gov (United States)

Jones, W Schuyler; Krucoff, Mitchell W; Morales, Pablo; Wilgus, Rebecca W; Heath, Anne H; Williams, Mary F; Tcheng, James E; Marinac-Dabic, J Danica; Malone, Misti L; Reed, Terrie L; Fukaya, Rie; Lookstein, Robert; Handa, Nobuhiro; Aronow, Herbert D; Bertges, Daniel J; Jaff, Michael R; Tsai, Thomas T; Smale, Joshua A; Zaugg, Margo J; Thatcher, Robert J; Cronenwett, Jack L; Nc, Durham; Md, Silver Spring; Japan, Tokyo; Ny, New York; Ri, Providence; Vt, Burlington; Mass, Newton; Colo, Denver; Ariz, Tempe; Calif, Santa Clara; Minn, Minneapolis; Nh, Lebanon

2018-01-25

The current state of evaluating patients with peripheral artery disease and more specifically of evaluating medical devices used for peripheral vascular intervention (PVI) remains challenging because of the heterogeneity of the disease process, the multiple physician specialties that perform PVI, the multitude of devices available to treat peripheral artery disease, and the lack of consensus about the best treatment approaches. Because PVI core data elements are not standardized across clinical care, clinical trials, and registries, aggregation of data across different data sources and physician specialties is currently not feasible.Methods and Results:Under the auspices of the U.S. Food and Drug Administration's Medical Device Epidemiology Network initiative-and its PASSION (Predictable and Sustainable Implementation of the National Registries) program, in conjunction with other efforts to align clinical data standards-the Registry Assessment of Peripheral Interventional Devices (RAPID) workgroup was convened. RAPID is a collaborative, multidisciplinary effort to develop a consensus lexicon and to promote interoperability across clinical care, clinical trials, and national and international registries of PVI. The current manuscript presents the initial work from RAPID to standardize clinical data elements and definitions, to establish a framework within electronic health records and health information technology procedural reporting systems, and to implement an informatics-based approach to promote the conduct of pragmatic clinical trials and registry efforts in PVI. Ultimately, we hope this work will facilitate and improve device evaluation and surveillance for patients, clinicians, health outcomes researchers, industry, policymakers, and regulators.

[RESEARCH PROGRESS OF PERIPHERAL NERVE SURGERY ASSISTED BY Da Vinci ROBOTIC SYSTEM].

Science.gov (United States)

Shen, Jie; Song, Diyu; Wang, Xiaoyu; Wang, Changjiang; Zhang, Shuming

2016-02-01

To summarize the research progress of peripheral nerve surgery assisted by Da Vinci robotic system. The recent domestic and international articles about peripheral nerve surgery assisted by Da Vinci robotic system were reviewed and summarized. Compared with conventional microsurgery, peripheral nerve surgery assisted by Da Vinci robotic system has distinctive advantages, such as elimination of physiological tremors and three-dimensional high-resolution vision. It is possible to perform robot assisted limb nerve surgery using either the traditional brachial plexus approach or the mini-invasive approach. The development of Da Vinci robotic system has revealed new perspectives in peripheral nerve surgery. But it has still been at the initial stage, more basic and clinical researches are still needed.

Pharmacokinetics of 2-nitroimidazole hypoxic cell radiosensitizers in rodent peripheral nervous tissue

International Nuclear Information System (INIS)

Sasai, K.; Shibamoto, Y.; Abe, M.; Takahashi, M.; Ito, T.; Nishimoto, S.

1990-01-01

The concentrations of seven 2-nitroimidazoles - including misonidazole, etanidazole (SR-2508), pimonidazole (Ro 03-8799), desmethylmisonidazole (Ro 05-9963), RK28, RP170 and KU2285 - were measured in the sciatic nerves of C3H/He mice using reverse-phase high-performance liquid chromatography. The apparent biological half-lives of the compounds in the peripheral nerves were correlated to their hydrophilicity: the more hydrophilic the compound, the longer the apparent biological half-life in the peripheral nervous tissue of the mice. Measurement of drug exposure in the rodent peripheral nervous system, rather than in the brain, was a better indicator for estimating the occurrence of clinical peripheral neuropathy by 2-nitroimidazoles. (author)

Pharmacokinetics of 2-nitroimidazole hypoxic cell radiosensitizers in rodent peripheral nervous tissue

Energy Technology Data Exchange (ETDEWEB)

Sasai, K.; Shibamoto, Y.; Abe, M. (Kyoto Univ. (Japan). Faculty of Medicine); Takahashi, M. (Kyoto Univ. (Japan). Chest Disease Research Inst.); Ito, T.; Nishimoto, S. (Kyoto Univ. (Japan). Faculty of Engineering)

1990-05-01

The concentrations of seven 2-nitroimidazoles - including misonidazole, etanidazole (SR-2508), pimonidazole (Ro 03-8799), desmethylmisonidazole (Ro 05-9963), RK28, RP170 and KU2285 - were measured in the sciatic nerves of C3H/He mice using reverse-phase high-performance liquid chromatography. The apparent biological half-lives of the compounds in the peripheral nerves were correlated to their hydrophilicity: the more hydrophilic the compound, the longer the apparent biological half-life in the peripheral nervous tissue of the mice. Measurement of drug exposure in the rodent peripheral nervous system, rather than in the brain, was a better indicator for estimating the occurrence of clinical peripheral neuropathy by 2-nitroimidazoles. (author).

Registry Assessment of Peripheral Interventional Devices (RAPID): Registry assessment of peripheral interventional devices core data elements.

Science.gov (United States)

Jones, W Schuyler; Krucoff, Mitchell W; Morales, Pablo; Wilgus, Rebecca W; Heath, Anne H; Williams, Mary F; Tcheng, James E; Marinac-Dabic, J Danica; Malone, Misti L; Reed, Terrie L; Fukaya, Rie; Lookstein, Robert A; Handa, Nobuhiro; Aronow, Herbert D; Bertges, Daniel J; Jaff, Michael R; Tsai, Thomas T; Smale, Joshua A; Zaugg, Margo J; Thatcher, Robert J; Cronenwett, Jack L

2018-02-01

The current state of evaluating patients with peripheral artery disease and more specifically of evaluating medical devices used for peripheral vascular intervention (PVI) remains challenging because of the heterogeneity of the disease process, the multiple physician specialties that perform PVI, the multitude of devices available to treat peripheral artery disease, and the lack of consensus about the best treatment approaches. Because PVI core data elements are not standardized across clinical care, clinical trials, and registries, aggregation of data across different data sources and physician specialties is currently not feasible. Under the auspices of the U.S. Food and Drug Administration's Medical Device Epidemiology Network initiative-and its PASSION (Predictable and Sustainable Implementation of the National Registries) program, in conjunction with other efforts to align clinical data standards-the Registry Assessment of Peripheral Interventional Devices (RAPID) workgroup was convened. RAPID is a collaborative, multidisciplinary effort to develop a consensus lexicon and to promote interoperability across clinical care, clinical trials, and national and international registries of PVI. The current manuscript presents the initial work from RAPID to standardize clinical data elements and definitions, to establish a framework within electronic health records and health information technology procedural reporting systems, and to implement an informatics-based approach to promote the conduct of pragmatic clinical trials and registry efforts in PVI. Ultimately, we hope this work will facilitate and improve device evaluation and surveillance for patients, clinicians, health outcomes researchers, industry, policymakers, and regulators. Copyright © 2017 Society for Vascular Surgery. All rights reserved.

Effects of Dioscoreae Rhizoma (SanYak on Peripheral Neuropathy and its Safety

Directory of Open Access Journals (Sweden)

Kim Min-jung

2013-09-01

Full Text Available Objectives: This study aimed to evaluate the evidence available in the literature for the safety and efficacy of Dioscoreae Rhizoma (DR for the treatment of peripheral neuropathy. Methods: Literature searches were performed in MEDLINE and three Korean medical databases up to April 2013. All studies evaluating the effects on peripheral neuropathy or the safety of DR monopreparations were considered. Results: Three studies - DR extract per os (po on diabetic neuropathy in mice, DR extract injection on the peripheral sciatic nerve after crush injury in rats and DR extract injection to patients with peripheral facial paralysis proved that DR treatments were effective for the treatment of nerve injuries. Conclusions: In conclusion, we found the DR has a strong positive potential for the treatment of peripheral neuropathy, but studies addressing direct factors related to the nerve still remain insufficient.

Donating Peripheral Blood Stem Cells

Science.gov (United States)

... Print this page My Cart Donating peripheral blood stem cells Peripheral blood stem cell (PBSC) donation is a nonsurgical procedure to collect ... Donating bone marrow Donor experiences videos Peripheral blood stem cell (PBSC) donation is one of two methods of ...

Visual tracking speed is related to basketball-specific measures of performance in NBA players.

Science.gov (United States)

Mangine, Gerald T; Hoffman, Jay R; Wells, Adam J; Gonzalez, Adam M; Rogowski, Joseph P; Townsend, Jeremy R; Jajtner, Adam R; Beyer, Kyle S; Bohner, Jonathan D; Pruna, Gabriel J; Fragala, Maren S; Stout, Jeffrey R

2014-09-01

The purpose of this study was to determine the relationship between visual tracking speed (VTS) and reaction time (RT) on basketball-specific measures of performance. Twelve professional basketball players were tested before the 2012-13 season. Visual tracking speed was obtained from 1 core session (20 trials) of the multiple object tracking test, whereas RT was measured by fixed- and variable-region choice reaction tests, using a light-based testing device. Performance in VTS and RT was compared with basketball-specific measures of performance (assists [AST]; turnovers [TO]; assist-to-turnover ratio [AST/TO]; steals [STL]) during the regular basketball season. All performance measures were reported per 100 minutes played. Performance differences between backcourt (guards; n = 5) and frontcourt (forward/centers; n = 7) positions were also examined. Relationships were most likely present between VTS and AST (r = 0.78; p basketball-specific performance measures. Backcourt players were most likely to outperform frontcourt players in AST and very likely to do so for VTS, TO, and AST/TO. In conclusion, VTS seems to be related to a basketball player's ability to see and respond to various stimuli on the basketball court that results in more positive plays as reflected by greater number of AST and STL and lower turnovers.

Visual Constructive and Visual-Motor Skills in Deaf Native Signers

Science.gov (United States)

Hauser, Peter C.; Cohen, Julie; Dye, Matthew W. G.; Bavelier, Daphne

2007-01-01

Visual constructive and visual-motor skills in the deaf population were investigated by comparing performance of deaf native signers (n = 20) to that of hearing nonsigners (n = 20) on the Beery-Buktenica Developmental Test of Visual-Motor Integration, Rey-Osterrieth Complex Figure Test, Wechsler Memory Scale Visual Reproduction subtest, and…

Peripheral Sympathectomy for Raynaud's Phenomenon: A Salvage Procedure

Directory of Open Access Journals (Sweden)

Wen-Her Wang

2006-10-01

Full Text Available We retrospectively reviewed the effectiveness of peripheral sympathectomy for severe Raynaud's phenomenon. In this study, a total of 14 digits from six patients with chronic digital ischemic change were included. All patients had pain, ulcer, or gangrenous change in the affected digits and were unresponsive to pharmacologic or other nonsurgical therapies. In all cases, angiography showed multifocal arterial lesions, so microvascular reconstruction was unfeasible. Peripheral sympathectomy was performed as a salvage procedure to prevent digit amputation. The results were analyzed according to reduction of pain, healing of ulcers, and prevention of amputation. In 12 of the 14 digits, the ulcers healed and amputation was avoided. In the other two digits, the ulcers improved and progressive gangrene was limited. As a salvage procedure for Raynaud's phenomenon recalcitrant to conservative treatment, peripheral sympathectomy improves perfusion to ischemic digits and enables amputation to be avoided.

Central and Peripheral Vision Loss Differentially Affects Contextual Cueing in Visual Search

Science.gov (United States)

Geringswald, Franziska; Pollmann, Stefan

2015-01-01

Visual search for targets in repeated displays is more efficient than search for the same targets in random distractor layouts. Previous work has shown that this contextual cueing is severely impaired under central vision loss. Here, we investigated whether central vision loss, simulated with gaze-contingent displays, prevents the incidental…

Multisensory teamwork: using a tactile or an auditory display to exchange gaze information improves performance in joint visual search.

Science.gov (United States)

Wahn, Basil; Schwandt, Jessika; Krüger, Matti; Crafa, Daina; Nunnendorf, Vanessa; König, Peter

2016-06-01

In joint tasks, adjusting to the actions of others is critical for success. For joint visual search tasks, research has shown that when search partners visually receive information about each other's gaze, they use this information to adjust to each other's actions, resulting in faster search performance. The present study used a visual, a tactile and an auditory display, respectively, to provide search partners with information about each other's gaze. Results showed that search partners performed faster when the gaze information was received via a tactile or auditory display in comparison to receiving it via a visual display or receiving no gaze information. Findings demonstrate the effectiveness of tactile and auditory displays for receiving task-relevant information in joint tasks and are applicable to circumstances in which little or no visual information is available or the visual modality is already taxed with a demanding task such as air-traffic control. Practitioner Summary: The present study demonstrates that tactile and auditory displays are effective for receiving information about actions of others in joint tasks. Findings are either applicable to circumstances in which little or no visual information is available or when the visual modality is already taxed with a demanding task.

In-Line Filtration Reduces Postoperative Venous Peripheral Phlebitis Associated With Cannulation: A Randomized Clinical Trial.

Science.gov (United States)

Villa, Gianluca; Chelazzi, Cosimo; Giua, Rosa; Tofani, Lorenzo; Zagli, Giovanni; Boninsegni, Paolo; Pinelli, Fulvio; De Gaudio, A Raffaele; Romagnoli, Stefano

2018-04-23

Peripheral venous cannulation is an everyday practice of care for patients undergoing anesthesia and surgery. Particles infused with intravenous fluids (eg, plastic/glass/drugs particulate) contribute to the pathogenesis of peripheral phlebitis. The aim of this study is to demonstrate the efficacy of in-line filtration in reducing the incidence of postoperative phlebitis associated with peripheral short-term vascular access. In this controlled trial, 268 surgical patients were randomly assigned to in-line filtration and standard care (NCT03193827). The incidence of phlebitis (defined as visual infusion phlebitis [VIP] score, ≥2) within 48 hours was compared between the 2 groups, as well as the onset and severity of phlebitis and the reasons for removal of the cannula. The lifespan of venous cannulae was compared for the in-line filter and no-filter groups through a Kaplan-Meier curve. The incidence of phlebitis within 48 hours postoperatively was 2.2% and 26.9% (difference, 25% [95% confidence interval {CI}, 12%-36%]; odds ratio, 0.05 [0.01-0.15]), respectively, for the in-line filter and no-filter groups (P phlebitis (hazard ratio, 0.05 [95% CI, 0.014-0.15]; P phlebitis and prolongs cannula lifespan during peripheral venous cannulation in surgical patients.

Visualizing Network Traffic to Understand the Performance of Massively Parallel Simulations

KAUST Repository

Landge, A. G.

2012-12-01

The performance of massively parallel applications is often heavily impacted by the cost of communication among compute nodes. However, determining how to best use the network is a formidable task, made challenging by the ever increasing size and complexity of modern supercomputers. This paper applies visualization techniques to aid parallel application developers in understanding the network activity by enabling a detailed exploration of the flow of packets through the hardware interconnect. In order to visualize this large and complex data, we employ two linked views of the hardware network. The first is a 2D view, that represents the network structure as one of several simplified planar projections. This view is designed to allow a user to easily identify trends and patterns in the network traffic. The second is a 3D view that augments the 2D view by preserving the physical network topology and providing a context that is familiar to the application developers. Using the massively parallel multi-physics code pF3D as a case study, we demonstrate that our tool provides valuable insight that we use to explain and optimize pF3D-s performance on an IBM Blue Gene/P system. © 1995-2012 IEEE.

A cane reduces loss of balance in patients with peripheral neuropathy: results from a challenging unipedal balance test.

Science.gov (United States)

Ashton-Miller, J A; Yeh, M W; Richardson, J K; Galloway, T

1996-05-01

To test the hypothesis that use of a cane in the nondominant hand during challenging balance tasks would significantly decrease loss of balance in patients with peripheral neuropathy while transferring from bipedal to unipedal stance on an unsteady surface. Nonrandomized control study. Tertiary-care institution. Eight consecutive patients with peripheral neuropathy (PN) and eight age- and gender-matched controls (C) with a mean (SD) age of 65 (8.2) years. Subjects were asked to transfer their weight onto their right foot, despite a rapid +/- 2 degrees or +/- 4 degrees frontal plane tilt of the support surface at 70% of weight transfer, and balance unipedally for at least 3 seconds. The efficacy of their weight transfer was evaluated over 112 consecutive randomized and blocked trials by calculating loss of balance as failure rates (%FR) with and without visual feedback, and with and without use of a cane in the nondominant (left) hand. Results were analyzed using a 2 x 2 x 2 x 2 x 2 repeated-measures analysis of variance (rm-ANOVA) and post hoc t tests. The rm-ANOVA showed that the FR of the PN subjects (47.6% [18.1%]) was significantly higher than C (29.2% [15.2%], p = .036). Removing visual feedback, simulating the dark of night, increased the FR fourfold (p = .000). Use of a cane in the contralateral nondominant hand significantly reduced the FR (p = .000), particularly in the PN group (cane x disease interaction: p = .055). Post hoc t tests showed that with or without visual feedback, the cane reduced the FR of the PN group fourfold and enabled them to perform more reliably than matched controls not using a cane (p = .011). An inversion perturbation resulted in a higher FR than an eversion perturbation (p = .007). The PN group employed larger mean peak cane forces (21.9% BW) than C (13.6% BW) in restoring their balance (p = .000). Use of a cane by PN patients significantly reduced their risk of losing balance on unstable surfaces, especially under low

Bingo! Externally-Supported Performance Intervention for Deficient Visual Search in Normal Aging, Parkinson’s Disease and Alzheimer’s Disease

Science.gov (United States)

Laudate, Thomas M.; Neargarder, Sandy; Dunne, Tracy E.; Sullivan, Karen D.; Joshi, Pallavi; Gilmore, Grover C.; Riedel, Tatiana M.; Cronin-Golomb, Alice

2011-01-01

External support may improve task performance regardless of an individual’s ability to compensate for cognitive deficits through internally-generated mechanisms. We investigated if performance of a complex, familiar visual search task (the game of bingo) could be enhanced in groups with suboptimal vision by providing external support through manipulation of task stimuli. Participants were 19 younger adults, 14 individuals with probable Alzheimer’s disease (AD), 13 AD-matched healthy adults, 17 non-demented individuals with Parkinson’s disease (PD), and 20 PD-matched healthy adults. We varied stimulus contrast, size, and visual complexity during game play. The externally-supported performance interventions of increased stimulus size and decreased complexity resulted in improvements in performance by all groups. Performance improvement through increased stimulus size and decreased complexity was demonstrated by all groups. AD also obtained benefit from increasing contrast, presumably by compensating for their contrast sensitivity deficit. The general finding of improved performance across healthy and afflicted groups suggests the value of visual support as an easy-to-apply intervention to enhance cognitive performance. PMID:22066941

Enhancing reading performance through action video games: the role of visual attention span.

Science.gov (United States)

Antzaka, A; Lallier, M; Meyer, S; Diard, J; Carreiras, M; Valdois, S

2017-11-06

Recent studies reported that Action Video Game-AVG training improves not only certain attentional components, but also reading fluency in children with dyslexia. We aimed to investigate the shared attentional components of AVG playing and reading, by studying whether the Visual Attention (VA) span, a component of visual attention that has previously been linked to both reading development and dyslexia, is improved in frequent players of AVGs. Thirty-six French fluent adult readers, matched on chronological age and text reading proficiency, composed two groups: frequent AVG players and non-players. Participants performed behavioural tasks measuring the VA span, and a challenging reading task (reading of briefly presented pseudo-words). AVG players performed better on both tasks and performance on these tasks was correlated. These results further support the transfer of the attentional benefits of playing AVGs to reading, and indicate that the VA span could be a core component mediating this transfer. The correlation between VA span and pseudo-word reading also supports the involvement of VA span even in adult reading. Future studies could combine VA span training with defining features of AVGs, in order to build a new generation of remediation software.

Tumors of peripheral nerves

International Nuclear Information System (INIS)

Ho, Michael; Lutz, Amelie M.

2017-01-01

Differentiation between malignant and benign tumors of peripheral nerves in the early stages is challenging; however, due to the unfavorable prognosis of malignant tumors early identification is required. To show the possibilities for detection, differential diagnosis and clinical management of peripheral nerve tumors by imaging appearance in magnetic resonance (MR) neurography. Review of current literature available in PubMed and MEDLINE, supplemented by the authors' own observations in clinical practice. Although not pathognomonic, several imaging features have been reported for a differentiation between distinct peripheral nerve tumors. The use of MR neurography enables detection and initial differential diagnosis in tumors of peripheral nerves. Furthermore, it plays an important role in clinical follow-up, targeted biopsy and surgical planning. (orig.) [de

Neural Correlates of Expert Visuomotor Performance in Badminton Players.

Science.gov (United States)

Hülsdünker, Thorben; Strüder, Heiko K; Mierau, Andreas

2016-11-01

Elite/skilled athletes participating in sports that require the initiation of targeted movements in response to visual cues under critical time pressure typically outperform nonathletes in a visuomotor reaction task. However, the exact physiological mechanisms of this advantage remain unclear. Therefore, this study aimed to determine the neurophysiological processes contributing to superior visuomotor performance in athletes using visual evoked potential (VEP). Central and peripheral determinants of visuomotor reaction time were investigated in 15 skilled badminton players and 28 age-matched nonathletic controls. To determine the speed of visual signal perception in the cortex, chromatic and achromatic pattern reversal stimuli were presented, and VEP values were recorded with a 64-channel EEG system. Further, a simple visuomotor reaction task was performed to investigate the transformation of the visual into a motor signal in the brain as well as the timing of muscular activation. Amplitude and latency of VEP (N75, P100, and N145) revealed that the athletes did not significantly differ from the nonathletes. However, visuomotor reaction time was significantly reduced in the athletes compared with nonathletes (athletes = 234.9 ms, nonathletes = 260.3 ms, P = 0.015). This was accompanied by an earlier activation of the premotor and supplementary motor areas (athletes = 163.9 ms, nonathletes = 199.1 ms, P = 0.015) as well as an earlier EMG onset (athletes = 167.5 ms, nonathletes = 206.5 ms, P < 0.001). The latency of premotor and supplementary motor area activation was correlated with EMG onset (r = 0.41) and visuomotor reaction time (r = 0.43). The results of this study indicate that superior visuomotor performance in athletes originates from faster visuomotor transformation in the premotor and supplementary motor cortical regions rather than from earlier perception of visual signals in the visual cortex.

Peripheral Neuropathy in Spinocerebellar Ataxia Type 1, 2, 3, and 6.

Science.gov (United States)

Linnemann, Christoph; Tezenas du Montcel, Sophie; Rakowicz, Maryla; Schmitz-Hübsch, Tanja; Szymanski, Sandra; Berciano, Jose; van de Warrenburg, Bart P; Pedersen, Karine; Depondt, Chantal; Rola, Rafal; Klockgether, Thomas; García, Antonio; Mutlu, Gurkan; Schöls, Ludger

2016-04-01

Spinocerebellar ataxias (SCAs) are characterized by autosomal dominantly inherited progressive ataxia but are clinically heterogeneous due to variable involvement of non-cerebellar parts of the nervous system. Non-cerebellar symptoms contribute significantly to the burden of SCAs, may guide the clinician to the underlying genetic subtype, and might be useful markers to monitor disease. Peripheral neuropathy is frequently observed in SCA, but subtype-specific features and subclinical manifestations have rarely been evaluated. We performed a multicenter nerve conduction study with 162 patients with genetically confirmed SCA1, SCA2, SCA3, and SCA6. The study proved peripheral nerves to be involved in the neurodegenerative process in 82 % of SCA1, 63 % of SCA2, 55 % of SCA3, and 22 % of SCA6 patients. Most patients of all subtypes revealed affection of both sensory and motor fibers. Neuropathy was most frequently of mixed type with axonal and demyelinating characteristics in all SCA subtypes. However, nerve conduction velocities of SCA1 patients were slower compared to other genotypes. SCA6 patients revealed less axonal damage than patients with other subtypes. No influence of CAG repeat length or biometric determinants on peripheral neuropathy could be identified in SCA1, SCA3, and SCA6. In SCA2, earlier onset and more severe ataxia were associated with peripheral neuropathy. We proved peripheral neuropathy to be a frequent site of the neurodegenerative process in all common SCA subtypes. Since damage to peripheral nerves is readily assessable by electrophysiological means, nerve conduction studies should be performed in a longitudinal approach to assess these parameters as potential progression markers.

2D Rotational Angiography for Fast and Standardized Evaluation of Peripheral and Visceral Artery Stenoses

International Nuclear Information System (INIS)

Katoh, Marcus; Opitz, Armin; Minko, Peter; Massmann, Alexander; Berlich, Joachim; Bücker, Arno

2011-01-01

Purpose: To investigate the value of rotational digital subtraction angiography (rDSA) for evaluation of peripheral and visceral artery stenoses compared to conventional digital subtraction angiography (cDSA). Methods: A phantom study was performed comparing the radiation dose of cDSA with two projections and rDSA by means of the 2D Dynavision technique (Siemens Medical Solutions, Forchheim, Germany). Subsequently, 33 consecutive patients (18 women, 15 men; mean ± SD age 67 ± 15 years) were examined by both techniques. In total, 63 vessel segments were analyzed by two observers with respect to stenoses, image contrast, and vessel sharpness. Results: Radiation dose was significantly lower with rDSA. cDSA and rDSA revealed 21 and 24 flow-relevant stenotic lesions and vessel occlusions (70–100%), respectively. The same stenosis grade was assessed in 45 segments. By means of rDSA, 10 lesions were judged to have a higher and 8 lesions a lower stenosis grade compared to cDSA. rDSA yielded additive information regarding the vessel anatomy and pathology in 29 segments. However, a tendency toward better image quality and sharper vessel visualization was seen with cDSA. Conclusion: rDSA allows for multiprojection assessment of peripheral and visceral arteries and provides additional clinically relevant information after a single bolus of contrast medium. At the same time, radiation dose can be significantly reduced compared to cDSA.

Using auditory-visual speech to probe the basis of noise-impaired consonant-vowel perception in dyslexia and auditory neuropathy

Science.gov (United States)

Ramirez, Joshua; Mann, Virginia

2005-08-01

Both dyslexics and auditory neuropathy (AN) subjects show inferior consonant-vowel (CV) perception in noise, relative to controls. To better understand these impairments, natural acoustic speech stimuli that were masked in speech-shaped noise at various intensities were presented to dyslexic, AN, and control subjects either in isolation or accompanied by visual articulatory cues. AN subjects were expected to benefit from the pairing of visual articulatory cues and auditory CV stimuli, provided that their speech perception impairment reflects a relatively peripheral auditory disorder. Assuming that dyslexia reflects a general impairment of speech processing rather than a disorder of audition, dyslexics were not expected to similarly benefit from an introduction of visual articulatory cues. The results revealed an increased effect of noise masking on the perception of isolated acoustic stimuli by both dyslexic and AN subjects. More importantly, dyslexics showed less effective use of visual articulatory cues in identifying masked speech stimuli and lower visual baseline performance relative to AN subjects and controls. Last, a significant positive correlation was found between reading ability and the ameliorating effect of visual articulatory cues on speech perception in noise. These results suggest that some reading impairments may stem from a central deficit of speech processing.

Influence of age, spatial memory, and ocular fixation on localization of auditory, visual, and bimodal targets by human subjects.

Science.gov (United States)

Dobreva, Marina S; O'Neill, William E; Paige, Gary D

2012-12-01

A common complaint of the elderly is difficulty identifying and localizing auditory and visual sources, particularly in competing background noise. Spatial errors in the elderly may pose challenges and even threats to self and others during everyday activities, such as localizing sounds in a crowded room or driving in traffic. In this study, we investigated the influence of aging, spatial memory, and ocular fixation on the localization of auditory, visual, and combined auditory-visual (bimodal) targets. Head-restrained young and elderly subjects localized targets in a dark, echo-attenuated room using a manual laser pointer. Localization accuracy and precision (repeatability) were quantified for both ongoing and transient (remembered) targets at response delays up to 10 s. Because eye movements bias auditory spatial perception, localization was assessed under target fixation (eyes free, pointer guided by foveal vision) and central fixation (eyes fixed straight ahead, pointer guided by peripheral vision) conditions. Spatial localization across the frontal field in young adults demonstrated (1) horizontal overshoot and vertical undershoot for ongoing auditory targets under target fixation conditions, but near-ideal horizontal localization with central fixation; (2) accurate and precise localization of ongoing visual targets guided by foveal vision under target fixation that degraded when guided by peripheral vision during central fixation; (3) overestimation in horizontal central space (±10°) of remembered auditory, visual, and bimodal targets with increasing response delay. In comparison with young adults, elderly subjects showed (1) worse precision in most paradigms, especially when localizing with peripheral vision under central fixation; (2) greatly impaired vertical localization of auditory and bimodal targets; (3) increased horizontal overshoot in the central field for remembered visual and bimodal targets across response delays; (4) greater vulnerability to

Peripheral dentinogenic ghost cell tumor

Directory of Open Access Journals (Sweden)

Sushant S Kamat

2013-01-01

Full Text Available Dentinogenic ghost cell tumors (DGCT are uncommon lesions mainly with rare peripheral types. This report presents a case of peripheral DGCT on the left side of the mandibular alveolar ridge of a heavy smoker, a 68-year-old man, with main presenting feature as a mild pain. Submandibular lymphadenopathy and radiological "saucerization" were evident. Differential diagnosis included fibroma, neurofibroma, peripheral ameloblastoma, peripheral odontogenic fibroma, and peripheral giant cell granuloma. Histologically, ameloblastoma-like epithelial elements were seen in association with grouped ghost cells. Proliferating polyhedral cells and stellate reticulum-like cells with various densities were spread over a wide range of the field. The lesion was curetted and after 2 years of follow up, it did not recur.

The impact of visual layout factors on performance in Web pages: a cross-language study.

Science.gov (United States)

Parush, Avi; Shwarts, Yonit; Shtub, Avy; Chandra, M Jeya

2005-01-01

Visual layout has a strong impact on performance and is a critical factor in the design of graphical user interfaces (GUIs) and Web pages. Many design guidelines employed in Web page design were inherited from human performance literature and GUI design studies and practices. However, few studies have investigated the more specific patterns of performance with Web pages that may reflect some differences between Web page and GUI design. We investigated interactions among four visual layout factors in Web page design (quantity of links, alignment, grouping indications, and density) in two experiments: one with pages in Hebrew, entailing right-to-left reading, and the other with English pages, entailing left-to-right reading. Some performance patterns (measured by search times and eye movements) were similar between languages. Performance was particularly poor in pages with many links and variable densities, but it improved with the presence of uniform density. Alignment was not shown to be a performance-enhancing factor. The findings are discussed in terms of the similarities and differences in the impact of layout factors between GUIs and Web pages. Actual or potential applications of this research include specific guidelines for Web page design.

The contributions of visual and central attention to visual working memory.