784 research outputs found
SaFiDe: detection of saccade and fixation periods based on eye-movement attributes from video-oculography, scleral coil or electrooculography data
In this work, we present SaFiDe, a deterministic method to detect eye movements (saccades and fixations) from eye-trace data. We developed this method for human and nonhuman primate data from video- and coil-recorded eye traces and further applied the algorithm to eye traces computed from electrooculograms. All the data analyzed were from free-exploration paradigms, where the main challenge was to detect periods of saccades and fixations that were uncued by the task. The method uses velocity and acceleration thresholds, calculated from the eye trace, to detect saccade and fixation periods. We show that our fully deterministic method detects saccades and fixations from eye traces during free visual exploration. The algorithm was implemented in MATLAB, and the code is publicly available on a GitHub repository. The algorithm presented is entirely deterministic, simplifying the comparison between subjects and tasks. Thus far, the algorithm presented can operate over video-based eye tracker data, human electrooculogram records, or monkey scleral eye coil data
Development of a Magnetoresistive-Based Wearable Eye-Tracking System for Oculomotor Assessment in Neurological and Otoneurological Research—Preliminary In Vivo Tests
Over the past 20 years, several eye-tracking technologies have been developed. This article aims to present a new type of eye tracker capable of producing detailed information on eye and head movements using an array of magnetoresistive detectors fixed on the patient’s head and a small magnet inserted into a contact lens, adapted to the curvature of the cornea of the subject. The software used for data analysis can combine or compare eye and head movements and can represent them as 2D or 3D images. Preliminary data involve an initial patient who was asked to perform several tasks to establish the accuracy, reliability, and tolerance of the magnetic eye tracker and software. The tasks included assessment of saccadic eye movements and pursuit, “drawing” alphabetic shapes or letters, and reading. Finally, a Head Impulse Test (HIT) was performed to estimate the VOR gain, comparing the standard deviation established via vHIT with that established via this magnetic eye tracker (mHIT). This prototypical device is minimally invasive, lightweight, relatively cheap, and tolerable, with a high degree of reliability and precision. All these characteristics could lead to the future use of the magnetic eye tracker in neurological and otoneurological fields
Reference Frames in Human Sensory, Motor, and Cognitive Processing
Reference-frames, or coordinate systems, are used to express properties and relationships of objects in the environment. While the use of reference-frames is well understood in physical sciences, how the brain uses reference-frames remains a fundamental question. The goal of this dissertation is to reach a better understanding of reference-frames in human perceptual, motor, and cognitive processing. In the first project, we study reference-frames in perception and develop a model to explain the transition from egocentric (based on the observer) to exocentric (based outside the observer) reference-frames to account for the perception of relative motion. In a second project, we focus on motor behavior, more specifically on goal-directed reaching. We develop a model that explains how egocentric perceptual and motor reference-frames can be coordinated through exocentric reference-frames. Finally, in a third project, we study how the cognitive system can store and recognize objects by using sensorimotor schema that allows mental rotation within an exocentric reference-frame
Eye movements used for the objective assessment of contrast sensitivity
Assessment of contrast sensitivity (CS) from eye movements has already been proposed as a possible
method to gain objective information about this visual function. The currently submitted dissertation holding
the title Eye movements used for the objective assessment of contrast sensitivity improves the currently
proposed approaches of the eye-movement-based CS tests and proposes novel ones.
The first project of this dissertation extends the applicability of microsaccadic rate signatures, already
proposed as the tool for objective CS testing, into the clinical practice by stimulation of microsaccades under
monocular conditions, while analyzing the eye movements as binocular events. In this approach an infra-red
filter for covering the left eye of the tested subjects and an infrared eye-tracker were used, resulting in the
stimulation of just one eye of the participant, however allowing the eye movement detection in both eyes.
Because the microsaccadic events were found to be rare in some participants, the second project utilized
optokinetic nystagmus in CS testing. In this project, the optokinetic nystagmus was detected in real-time when
running the experiment, using a newly-developed life detection method, and along with a one-dimensional
adaptive psychometric procedure (QUEST+) for the contrast level management enabled a fully automated CS
examination. Furthermore, the examination was conducted for a range of spatial frequencies of a grating as
well as a range of defocus conditions, replicating the well-known effects on CS from the clinical trials.
The third project aimed to extend the eye-movement-based testing also to the peripheral visual field, and thus
replicate the CS perimetry testing procedure in an objective way. In this project CS was tested using reflexive
(reactive) saccades, occurring towards a newly presented target, which was located in one of the four cardinal
directions in the patient’s visual field. Here the four independent QUEST+ psychometric procedures sought for
the contrast threshold in the four directions individually, for each of the three tested eccentricity levels.
Moreover, the measurements were conducted for the eye-movement-based and key-board-based
measurements to run a rounded validation of this novel procedure, showing its feasibility for future clinical
application. In conclusion, this thesis extends an improves the portfolio of eye movements used in CS testing, shows novel approaches to improve the time efficiency, and replicates the well-known effects from the clinical
trials
Fictional Practices of Spirituality I: Interactive Media
"Fictional Practices of Spirituality" provides critical insight into the implementation of belief, mysticism, religion, and spirituality into worlds of fiction, be it interactive or non-interactive. This first volume focuses on interactive, virtual worlds - may that be the digital realms of video games and VR applications or the imaginary spaces of life action role-playing and soul-searching practices. It features analyses of spirituality as gameplay facilitator, sacred spaces and architecture in video game geography, religion in video games and spiritual acts and their dramaturgic function in video games, tabletop, or LARP, among other topics. The contributors offer a first-time ever comprehensive overview of play-rites as spiritual incentives and playful spirituality in various medial incarnations
Landmark Visualization on Mobile Maps – Effects on Visual Attention, Spatial Learning, and Cognitive Load during Map-Aided Real-World Navigation of Pedestrians
Even though they are day-to-day activities, humans find navigation and wayfinding to be cognitively challenging. To facilitate their everyday mobility, humans increasingly rely on ubiquitous mobile maps as navigation aids. However, the over-reliance on and habitual use of omnipresent navigation aids deteriorate humans' short-term ability to learn new information about their surroundings and induces a long-term decline in spatial skills. This deterioration in spatial learning is attributed to the fact that these aids capture users' attention and cause them to enter a passive navigation mode. Another factor that limits spatial learning during map-aided navigation is the lack of salient landmark information on mobile maps.
Prior research has already demonstrated that wayfinders rely on landmarks—geographic features that stand out from their surroundings—to facilitate navigation and build a spatial representation of the environments they traverse. Landmarks serve as anchor points and help wayfinders to visually match the spatial information depicted on the mobile map with the information collected during the active exploration of the environment. Considering the acknowledged significance of landmarks for human wayfinding due to their visibility and saliency, this thesis investigates an open research question: how to graphically communicate landmarks on mobile map aids to cue wayfinders' allocation of attentional resources to these task-relevant environmental features. From a cartographic design perspective, landmarks can be depicted on mobile map aids on a graphical continuum ranging from abstract 2D text labels to realistic 3D buildings with high visual fidelity. Based on the importance of landmarks for human wayfinding and the rich cartographic body of research concerning their depiction on mobile maps, this thesis investigated how various landmark visualization styles affect the navigation process of two user groups (expert and general wayfinders) in different navigation use contexts (emergency and general navigation tasks). Specifically, I conducted two real-world map-aided navigation studies to assess the influence of various landmark visualization styles on wayfinders' navigation performance, spatial learning, allocation of visual attention, and cognitive load.
In Study I, I investigated how depicting landmarks as abstract 2D building footprints or realistic 3D buildings on the mobile map affected expert wayfinders' navigation performance, visual attention, spatial learning, and cognitive load during an emergency navigation task. I asked expert navigators recruited from the Swiss Armed Forces to follow a predefined route using a mobile map depicting landmarks as either abstract 2D building footprints or realistic 3D buildings and to identify the depicted task-relevant landmarks in the environment. I recorded the experts' gaze behavior with a mobile eye-tracer and their cognitive load with EEG during the navigation task, and I captured their incidental spatial learning at the end of the task. The wayfinding experts' exhibited high navigation performance and low cognitive load during the map-aided navigation task regardless of the landmark visualization style. Their gaze behavior revealed that wayfinding experts navigating with realistic 3D landmarks focused more on the visualizations of landmarks on the mobile map than those who navigated with abstract 2D landmarks, while the latter focused more on the depicted route. Furthermore, when the experts focused for longer on the environment and the landmarks, their spatial learning improved regardless of the landmark visualization style. I also found that the spatial learning of experts with self-reported low spatial abilities improved when they navigated with landmarks depicted as realistic 3D buildings.
In Study II, I investigated the influence of abstract and realistic 3D landmark visualization styles on wayfinders sampled from the general population. As in Study I, I investigated wayfinders' navigation performance, visual attention, spatial learning, and cognitive load. In contrast to Study I, the participants in Study II were exposed to both landmark visualization styles in a navigation context that mimics everyday navigation. Furthermore, the participants were informed that their spatial knowledge of the environment would be tested after navigation. As in Study I, the wayfinders in Study II exhibited high navigation performance and low cognitive load regardless of the landmark visualization style. Their visual attention revealed that wayfinders with low spatial abilities and wayfinders familiar with the study area fixated on the environment longer when they navigated with realistic 3D landmarks on the mobile map. Spatial learning improved when wayfinders with low spatial abilities were assisted by realistic 3D landmarks. Also, when wayfinders were assisted by realistic 3D landmarks and paid less attention to the map aid, their spatial learning improved.
Taken together, the present real-world navigation studies provide ecologically valid results on the influence of various landmark visualization styles on wayfinders. In particular, the studies demonstrate how visualization style modulates wayfinders' visual attention and facilitates spatial learning across various user groups and navigation use contexts. Furthermore, the results of both studies highlight the importance of individual differences in spatial abilities as predictors of spatial learning during map-assisted navigation. Based on these findings, the present work provides design recommendations for future mobile maps that go beyond the traditional concept of "one fits all." Indeed, the studies support the cause for landmark depiction that directs individual wayfinders' visual attention to task-relevant landmarks to further enhance spatial learning. This would be especially helpful for users with low spatial skills. In doing so, future mobile maps could dynamically adapt the visualization style of landmarks according to wayfinders' spatial abilities for cued visual attention, thus meeting individuals' spatial learning needs
Propaedeutics of Internal Diseases
УЧЕБНЫЕ ПОСОБИЯДИАГНОСТИКАПИЩЕВАРИТЕЛЬНОЙ СИСТЕМЫ БОЛЕЗНИ /ДИАГНОСТИКАМОЧЕПОЛОВЫЕ БОЛЕЗНИ /ДИАГНОСТИКАГЕМАТОЛОГИЧЕСКИЕ БОЛЕЗНИ /ДИАГНОСТИКАДИАГНОСТИЧЕСКИЕ МЕТОДЫ ЭНДОКРИННЫЕДИАГНОСТИЧЕСКИЕ МЕТОДЫ ПИЩЕВАРИТЕЛЬНЫЕКОСТНО-МЫШЕЧНОЙ СИСТЕМЫ БОЛЕЗНИ /ДИАГНОСТИКАТЕРАПИЯ (ДИСЦИПЛИНА)DISEASES OF THE ENDOCRINE GLANDSDISEASES OF THE MUSCULOSKELETAL SYSTEMDISEASES OF THE BLOODDISEASES OF THE URINARY TRACTDISEASES OF THE DIGESTIVE SYSTEMINTERNAL DISEASESPROPAEDEUTICS OF INTERNAL DISEASESINTERNAL MEDICINEИНОСТРАННЫЕ СТУДЕНТЫСодержит следующие разделы: обследование пациентов с заболеваниями органов систем пищеварения, мочевыделения, крови, желез внутренней секреции и опорно-двигательного аппарата. Для студентов 2 и 3 курсов, изучающих пропедевтику внутренних болезней на английском языке. It contains the following sections: examination of patients with diseases of the digestive system, urinary tract, blood, endocrine glands and musculoskeletal system
- …