Gaze Fixation Research Articles

Эффективность применения световой нервно-зрительной стимуляции у детей младенческого возраста с задержкой зрительного созревания

Purpose. To study the effectiveness of neuro-visual light stimulation in infants with delayed visual maturation (DVM). Material and methods. The study involved 22 infants with DVM at the age of 2–3 months. In all children, the movements of the eyeballs were insufficiently coordinated; there were also no visual reflexes of tracking and stable fixation. All patients were divided into two groups – the main (12 people) and comparison (10 people). Children of both groups received neurotropic therapy. Additionally, patients of the main group were prescribed light therapy of fontanelles with the Bioptron device daily for 30 seconds in one session (15 seconds for each fontanel). The duration of the course was 15 days with a frequency of course treatment every 1–1.5 months until the desired therapeutic effect is obtained. Efficiency criteria: the rate of development of visual functions and behavioral reactions corresponding to the variant of the age norm. Results. After the first course of using the Bioptron device, 8 out of 12 children of the main group developed a tracking reaction, gaze fixation, and consistency in the movements of the eyeballs. In three children – only after the second course of light therapy, and in one child – after the third course of treatment. In the control group, two out of 10 children after 15 days from the start of neurotropic therapy developed eye movement coordination, a stable reaction to tracking objects, and stable gaze fixation; in the remaining 8 children, these reactions appeared only 5 months after the start of treatment. Conclusion. Neuro-visual light stimulation, as an addition to pharmaconeuroprotection, significantly reduces the time for the formation of normal visual functions in case of DVM. Keywords: neuro-visual light stimulation, delayed visual maturation, Bioptron.

Beyond gaze fixation: Modeling peripheral vision in relation to speed, Tesla Autopilot, cognitive load, and age in highway driving

ObjectiveThe study aims to model driver perception across the visual field in dynamic, real-world highway driving. BackgroundPeripheral vision acquires information across the visual field and guides a driver’s information search. Studies in naturalistic settings are lacking however, with most research having been conducted in controlled simulation environments with limited eccentricities and driving dynamics. MethodsWe analyzed data from 24 participants who drove a Tesla Model S with Autopilot on the highway. While driving, participants completed the peripheral detection task (PDT) using LEDs and the N-back task to generate cognitive load. The I-DT (identification by dispersion threshold) algorithm sampled naturalistic gaze fixations during PDTs to cover a broader and continuous spectrum of eccentricity. A generalized Bayesian regression model predicted LED detection probability during the PDT—as a surrogate for peripheral vision—in relation to eccentricity, vehicle speed, driving mode, cognitive load, and age. ResultsThe model predicted that LED detection probability was high and stable through near-peripheral vision but it declined rapidly beyond 20°-30° eccentricity, showing a narrower useful field over a broader visual field (maximum 70°) during highway driving. Reduced speed (while following another vehicle), cognitive load, and older age were the main factors that degraded the mid-peripheral vision (20°-50°), while using Autopilot had little effect. ConclusionsDrivers can reliably detect objects through near-peripheral vision, but their peripheral detection degrades gradually due to further eccentricity, foveal demand during low-speed vehicle following, cognitive load, and age. ApplicationsThe findings encourage the development of further multivariate computational models to estimate peripheral vision and assess driver situation awareness for crash prevention.

The contributions of eye gaze fixations and target-lure similarity to behavioral and fMRI indices of pattern separation and pattern completion

ABSTRACT Pattern separation and pattern completion are generally studied in humans using mnemonic discrimination tasks such as the Mnemonic Similarity Task (MST) where participants identify similar lures and repeated items from a series of images. Failures to correctly discriminate lures are thought to reflect a failure of pattern separation and a propensity toward pattern completion. Recent research has challenged this perspective, suggesting that poor encoding rather than pattern completion accounts for the occurrence of false alarm responses to similar lures. In two experiments, participants completed a continuous recognition task version of the MST while eye movement (Experiments 1 and 2) and fMRI data (Experiment 2) were collected. In Experiment 1, we replicated the result that fixation counts at study predicted accuracy on lure trials (consistent with poor encoding predicting mnemonic discrimination performance), but this effect was not observed in our fMRI task. In both experiments, we found that target-lure similarity was a strong predictor of accuracy on lure trials. Further, we found that fMRI activation changes in the hippocampus were significantly correlated with the number of fixations at study for correct but not incorrect mnemonic discrimination judgments when controlling for target-lure similarity. Our findings indicate that while eye movements during encoding predict subsequent hippocampal activation changes for correct mnemonic discriminations, the predictive power of eye movements for activation changes for incorrect mnemonic discrimination trials was modest at best.

Manipulating image luminance to improve eye gaze and verbal behavior in autistic children

Autism has been characterized by a tendency to attend to the local visual details over surveying an image to understand the gist–a phenomenon called local interference. This sensory processing trait has been found to negatively impact social communication. Although much work has been conducted to understand these traits, little to no work has been conducted to intervene to provide support for local interference. Additionally, recent understanding of autism now introduces the core role of sensory processing and its impact on social communication. However, no interventions to the end of our knowledge have been explored to leverage this relationship. This work builds on the connection between visual attention and semantic representation in autistic children. In this work, we ask the following research questions: RQ1: Does manipulating image characteristics of luminance and spatial frequency increase likelihood of fixations in hot spots (Areas of Interest) for autistic children? RQ2: Does manipulating low-level image characteristics of luminance and spatial frequency increase the likelihood of global verbal responses for autistic children? We sought to manipulate visual attention as measured by eye gaze fixations and semantic representation of verbal response to the question “What is this picture about?”. We explore digital strategies to offload low-level, sensory processing of global features via digital filtering. In this work, we designed a global filter to reduce image characteristics found to be distracting for autistic people and compared baseline images to featured images in 11 autistic children. Participants saw counterbalanced images way over 2 sessions. Eye gaze in areas of interest and verbal responses were collected and analyzed. We found that luminance in non-salient areas impacted both eye gaze and verbal responding–however in opposite ways (however versus high levels of luminance). Additionally, the interaction of luminance and spatial frequency in areas of interest is also significant. This is the first empirical study in designing an assistive technology aimed to augment global processing that occurs at a sensory-processing and social-communication level. Contributions of this work include empirical findings regarding the quantification of local interference in images of natural scenes for autistic children in real-world settings; digital methods to offload global visual processing to make this information more accessible via insight on the role of luminance and spatial frequency in visual perception of and semantic representation in images of natural scenes.

Delay of gaze fixation during reaching movement with the non-dominant hand to a distant target.

The present study examined the effects of hand and task difficulty on eye-hand coordination related to gaze fixation behavior (i.e., fixating a gaze to the target until reach completion) in single reaching movements. Twenty right-handed young adults made reaches on a digitizer, while looking at a visual target and feedback of hand movements on a computer monitor. Task difficulty was altered by having three target distances. In a small portion of trials, visual feedback was randomly removed at the target presentation. The effect of a moderate amount of practice was also examined using a randomized trial schedule across target-distance and visual-feedback conditions in each hand. The results showed that the gaze distances covered during the early reaching phase were reduced, and the gaze fixation to the target was delayed when reaches were performed with the left hand and when the target distance increased. These results suggest that when the use of the non-dominant hand or an increased task difficulty reduces the predictability of hand movements and its sensory consequences, eye-hand coordination is modified to enhance visual monitoring of the reach progress prior to gaze fixation. The randomized practice facilitated this process. Nevertheless, variability of reach trajectory was more increased without visual feedback for right-hand reaches, indicating that control of the dominant arm integrates more visual feedback information during reaches. These results together suggest that the earlier gaze fixation and greater integration of visual feedback during right-hand reaches contribute to the faster and more accurate performance in the final reaching phase.

EasyGaze: Hybrid eye tracking approach for handheld mobile devices

BackgroundEye-tracking technology for mobile devices has made significant progress. However, owing to limited computing capacity and the complexity of context, the conventional image feature-based technology cannot extract features accurately, thus affecting the performance. MethodsThis study proposes a novel approach by combining appearance- and feature-based eye-tracking methods. Face and eye region detections were conducted to obtain features that were used as inputs to the appearance model to detect the feature points. The feature points were used to generate feature vectors, such as corner center-pupil center, by which the gaze fixation coordinates were calculated. ResultsTo obtain feature vectors with the best performance, we compared different vectors under different image resolution and illumination conditions, and the results indicated that the average gaze fixation accuracy was achieved at a visual angle of 1.93° when the image resolution was 96 × 48 pixels, with light sources illuminating from the front of the eye. ConclusionsCompared with the current methods, our method improved the accuracy of gaze fixation and it was more usable.

Изменение функциональных параметров центрального отдела сетчатки при использовании различных методик блокирования незакрывшегося макулярного разрыва

Over the past decades, the surgical treatment of macular holes has been developing more and more rapidly, new methods of blocking an anatomical defect in the central part of the retina are emerging. However, the percentage of macular holes recurrence remains still high, according to various literary foreign and domestic sources, from 3 to 30 %. Purpose. Еvaluate the functional parameters of the retina using various methods of blocking an unclosed macular hole (creating a free ILM flap with the application of ACP-mass and tamponade with an air-gas mixture or creating a free ILM flap in combination with silicone oil tamponade). Material and methods. This study involved 92 patients, the patients were divided into groups according to the principle of repeated surgical intervention, the visual acuity, stability and displacement of the fixation point were studied in all patients. Results. In patients of both groups, an improvement in the functional parameters of the retina was noted, however, visual acuity and gaze fixation were better in the group with gas tamponade. Conclusion. Both proposed techniques for closing previously unblocked MRs are highly effective, however, the technique using a free ILM flap, application of ACP-mass and tamponade with an air-gas mixture provides better functional results due to the absence of toxic and mechanical effects of SO. Keywords: macular rupture, free flap, silicone oil, ACP mass, gas-air mixture, fixation point

Effect of Perinatal Dioxin Exposure Originating from Agent Orange on Gaze Behavior in 3-Year-Old Children Living in the Most Dioxin-Contaminated Areas in Vietnam.

We investigated the effect of perinatal dioxin exposure indicated by dioxins in breast milk on children’s gaze behavior. We studied 142 children aged 3 years from the 2012 Bien Hoa birth cohort in a hotspot of dioxin contamination in Vietnam. Children’s faces were viewed using the eye-tracking method. Associations between gaze behavior of faces and neurodevelopmental indices and head circumference were analyzed to determine whether poor gaze behavior indicates increased autistic traits in these children. The gaze fixation duration on facial areas when viewing 10 still images of children was calculated as the gaze behavior index. Autistic behavior was assessed using the Autism Spectrum Rating Scale, and language development was evaluated by the Bayley Scales of Infant and Toddler Development, Ver. 3. The face fixation duration (%) significantly decreased as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations increased in a dose–effect manner in girls, which suggested atypical gaze behavior for watching human faces. Furthermore, these girls with atypical gaze behavior showed lower social communication scores and smaller head sizes, suggesting increased autistic traits in girls. In conclusion, our findings show sex-specific effects (girls > boys) of perinatal TCDD exposure on gaze behavior in young children.

Central-peripheral dichotomy: color-motion and luminance-motion binding show stronger top-down feedback in central vision.

Recently a theory (Zhaoping, Vision Research, 136, 32-49, 2017) proposed that top-down feedback from higher to lower visual cortical areas, to aid visual recognition, is stronger in the central than in the peripheral visual fields. Since top-down feedback helps feature binding, a critical visual recognition process, this theory predicts that insufficient feedback in the periphery should make feature misbinding more likely. To test this prediction, this study assessed binding between color and motion features, or between luminance and motion features, at different visual field eccentricities. We first used color-motion stimuli containing equiluminant red and green dots moving in opposite directions, for example, red dots moved leftward while green dots moved rightward. Such stimuli were shown in both a central reference strip and a peripheral test strip; participants reported whether it was the first or second interval in a trial in which the dots of each color moved in the opposite directions between the two strips. The center of the test strip was at 4° or 15° away from the gaze fixation. Participants' performance was much worse when the test strip was more peripheral, suggesting that feature misbinding occurred more frequently there. This held even when the size and density of the dots were adjusted by eccentricity-dependent cortical magnification factors, and even when red/green dots were replaced by yellow/blue dots or black/white dots to suit the retinal input sampling peripherally. Our findings support that top-down feedback is more directed to central vision, which can resolve ambiguities in feature binding at more central visual locations.

LAG-1: A dynamic, integrative model of learning, attention, and gaze.

It is clear that learning and attention interact, but it is an ongoing challenge to integrate their psychological and neurophysiological descriptions. Here we introduce LAG-1, a dynamic neural field model of learning, attention and gaze, that we fit to human learning and eye-movement data from two category learning experiments. LAG-1 comprises three control systems: one for visuospatial attention, one for saccadic timing and control, and one for category learning. The model is able to extract a kind of information gain from pairwise differences in simple associations between visual features and categories. Providing this gain as a reentrant signal with bottom-up visual information, and in top-down spatial priority, appropriately influences the initiation of saccades. LAG-1 provides a moment-by-moment simulation of the interactions of learning and gaze, and thus simultaneously produces phenomena on many timescales, from the duration of saccades and gaze fixations, to the response times for trials, to the slow optimization of attention toward task relevant information across a whole experiment. With only three free parameters (learning rate, trial impatience, and fixation impatience) LAG-1 produces qualitatively correct fits for learning, behavioural timing and eye movement measures, and also for previously unmodelled empirical phenomena (e.g., fixation orders showing stimulus-specific attention, and decreasing fixation counts during feedback). Because LAG-1 is built to capture attention and gaze generally, we demonstrate how it can be applied to other phenomena of visual cognition such as the free viewing of visual stimuli, visual search, and covert attention.

Nonspecific Effects of Normal Aging on Taxonomic and Thematic Semantic Processing

ABSTRACT Objective This study aimed to assess the effect of normal aging on the processing of taxonomic and thematic semantic relations. Method We used the Visual-World-Paradigm coupled with eye-movement recording. We compared performance of healthy younger and older adults on a word-to-picture matching task in which participants had to identify each target among semantically related (taxonomic or thematic) and unrelated distractors. Results Younger and older participants exhibited similar patterns of gaze fixations in the two semantic conditions. The effect of aging took the form of an overall reduction in sensitivity to semantic competitors, with no difference between the taxonomic and thematic conditions. Moreover, comparison of the proportions of fixations between the younger and older participants indicated that targets were identified equally quickly in both age groups. This was not the case when mouse-click reaction times were analyzed. Conclusions Findings argue in favor of nonspecific effects of normal aging on semantic processing that similarly affect taxonomic and thematic processing. There are important clinical implications, as pathological aging has been repeatedly shown to selectively affect either taxonomic or thematic relations. Measuring eye-movements in a semantic task is also an interesting approach in the elderly, as these seem to be less impacted by aging than other motor responses.

Eye-Tracking Technology to Determine Procedural Proficiency in Ultrasound-Guided Regional Anesthesia.

Eye-tracking measures attention patterns, which may offer insight into evaluating procedural expertise. The purpose of this study was to determine the feasibility of using eye tracking to assess visual fixation patterns when performing an ultrasound-guided regional anesthesia procedure and to assess for differences between experienced, intermediate, and novice practitioners. Participants performed an ultrasound-guided sciatic nerve block 3 times on a fresh cadaver model while wearing eye-tracking glasses. Gaze fixation and dwell time on each location were compared between participants. Eye-gaze paths were used to derive a measure of entropy, or how often participants switched gaze fixations between locations. Five attending anesthesiologists, 5 third-year anesthesiology residents with prior ultrasound-guided regional anesthesia experience, and 5 medical students completed the study. Individuals with more experience were more likely to successfully perform the sciatic nerve block (5/5 attendings, 5/5 residents, 0/5 students; P = .002) and performed the procedure faster (average: attendings 62.6 seconds, residents 106.4 seconds, students 134.4 seconds; P = .089). Participants were progressively faster with practice (Trial 1: 41.8 seconds, Trial 2: 29.2 seconds, Trial 3: 28.9 seconds; P = .012), and the average number of eye shifts per trial decreased from 10.8 to 6.5 to 6 (P = .010). Attending physicians spent significantly less time fixating on the ultrasound monitor compared to trainees (P = .035). Average visual entropy progressively decreased from Trial 1 to Trial 3 (P = .03) and with greater experience (P = .15). There was a strong correlation between entropy and time on task (r(16) = 0.826, P = .001). Experienced providers make fewer back-and-forth visual fixations, spend less time in the procedure, and demonstrate less entropy during ultrasound-guided regional anesthesia procedures. Mobile eye-tracking has the potential to provide additional objective measures of performance that may help not only determine procedural competence but also distinguish between levels of proficiency.

Change Blindness in Adolescents With Attention-Deficit/Hyperactivity Disorder: Use of Eye-Tracking.

ObjectiveThis study investigated change detection of central or marginal interest in images using a change-blindness paradigm with eye tracking.MethodEighty-four drug-naïve adolescents [44 with attention-deficit/hyperactivity disorder (ADHD)/40 controls with typical development] searched for a change in 36 pairs of original and modified images, with an item of central or marginal interest present or absent, presented in rapid alternation. Collected data were detection rate, response time, and gaze fixation duration, latency, and dispersion data.ResultsBoth groups' change-detection times were similar, with no speed–accuracy trade-off. No between-group differences were found in time to first fixation, fixation duration, or scan paths. Both groups performed better for items of central level of interest. The ADHD group demonstrated greater fixation dispersion in scan paths for central- and marginal-interest items.ConclusionResults suggest the greater gaze dispersion may lead to greater fatigue in tasks that require longer attention duration.

The Static and Dynamic Analyses of Drivers’ Gaze Movement Using VR Driving Simulator

Drivers collect information of road and traffic conditions through a visual search while driving to avoid any potential hazards they perceive. Novice drivers with lack of driving experience may be involved in a car accident as they misjudge the information obtained by insufficient visual search with a narrower field of vision than experienced drivers do. In this regard, the current study compared and identified the gap between novice and experienced drivers in regard to the information they obtained in a visual search of gaze movement and visual attention. A combination of a static analysis, based on the dwell time, fixation duration, the number of fixations and stationary gaze entropy in visual search, and a dynamic analysis using gaze transition entropy was applied. The static analysis on gaze indicated that the group of novice drivers showed a longer dwell time on the traffic lights, pedestrians, and passing vehicles, and a longer fixation duration on the navigation system and the dashboard than the experienced ones. Also, the novice had their eyes fixed on the area of interests straight ahead more frequently while driving at an intersection. In addition, the novice group demonstrated less information at 2.60 bits out of the maximum stationary gaze entropy of 3.32 bits that a driver can exhibit, which indicated that their gaze fixations were concentrated. Meanwhile, the experienced group displayed approx. 3.09 bits, showing that their gaze was not narrowed on a certain area of interests, but was relatively evenly distributed. The dynamic analysis results showed that the novice group conducted the most gaze transitions between traffic lights, pedestrians and passing vehicles, whereas experienced drivers displayed the most transitions between the right- and left-side mirrors, passing vehicles, pedestrians, and traffic lights to find more out about the surrounding traffic conditions. In addition, the experienced group (3.04 bits) showed a higher gaze transition entropy than the novice group (2.21 bits). This indicated that a larger entropy was required to understand the visual search data because visual search strategies changed depending on the situations.

Research of visual attention in basketball shooting: A systematic review with meta-analysis

Visual attention has a significant impact on shooting performance in basketball. Over the past 35 years, researchers have explored individual concepts of visual attention, such as gaze fixation, the number and direction of saccades, and their effects on shooting accuracy. The last gaze fixation, also known as the quiet eye, was found to be particularly important. The aim of this paper was therefore to systematically review the literature to present how visual attention and the quiet eye contribute to shooting performance and how they are affected by anxiety, training, defensive pressure, and fatigue. The 26 articles selected were divided into two categories; the first category included studies that examined visual attention during free throws, and the second category included studies examining jump shots. In addition, we performed a meta-analytic comparison to determine whether the duration of the quiet eye differs with respect to temporal constraints. Results show that for both jump shots with or without defence and free throws, a longer quiet eye durations and a lower number of gaze fixations are associated with better performance. For a successful shot, the quiet eye phase must occur at the right moment, which is likely due to visuomotor reaction latency prior to elbow extension. Furthermore, improvement in shooting performance can be achieved through quiet eye training or traditional training. Nevertheless, individual factors such as quiet eye timing, systematic training, and visual attention in top basketball players of different playing positions need to be further explored as this will provide even more information for individual’s improvement.

Identification of Social Engagement Indicators Associated With Autism Spectrum Disorder Using a Game-Based Mobile App: Comparative Study of Gaze Fixation and Visual Scanning Methods.

BackgroundAutism spectrum disorder (ASD) is a widespread neurodevelopmental condition with a range of potential causes and symptoms. Standard diagnostic mechanisms for ASD, which involve lengthy parent questionnaires and clinical observation, often result in long waiting times for results. Recent advances in computer vision and mobile technology hold potential for speeding up the diagnostic process by enabling computational analysis of behavioral and social impairments from home videos. Such techniques can improve objectivity and contribute quantitatively to the diagnostic process.ObjectiveIn this work, we evaluate whether home videos collected from a game-based mobile app can be used to provide diagnostic insights into ASD. To the best of our knowledge, this is the first study attempting to identify potential social indicators of ASD from mobile phone videos without the use of eye-tracking hardware, manual annotations, and structured scenarios or clinical environments.MethodsHere, we used a mobile health app to collect over 11 hours of video footage depicting 95 children engaged in gameplay in a natural home environment. We used automated data set annotations to analyze two social indicators that have previously been shown to differ between children with ASD and their neurotypical (NT) peers: (1) gaze fixation patterns, which represent regions of an individual’s visual focus and (2) visual scanning methods, which refer to the ways in which individuals scan their surrounding environment. We compared the gaze fixation and visual scanning methods used by children during a 90-second gameplay video to identify statistically significant differences between the 2 cohorts; we then trained a long short-term memory (LSTM) neural network to determine if gaze indicators could be predictive of ASD.ResultsOur results show that gaze fixation patterns differ between the 2 cohorts; specifically, we could identify 1 statistically significant region of fixation (P<.001). In addition, we also demonstrate that there are unique visual scanning patterns that exist for individuals with ASD when compared to NT children (P<.001). A deep learning model trained on coarse gaze fixation annotations demonstrates mild predictive power in identifying ASD.ConclusionsUltimately, our study demonstrates that heterogeneous video data sets collected from mobile devices hold potential for quantifying visual patterns and providing insights into ASD. We show the importance of automated labeling techniques in generating large-scale data sets while simultaneously preserving the privacy of participants, and we demonstrate that specific social engagement indicators associated with ASD can be identified and characterized using such data.

Hybrid FPGA-CPU-Based Architecture for Object Recognition in Visual Servoing of Arm Prosthesis.

The present paper proposes an implementation of a hybrid hardware–software system for the visual servoing of prosthetic arms. We focus on the most critical vision analysis part of the system. The prosthetic system comprises a glass-worn eye tracker and a video camera, and the task is to recognize the object to grasp. The lightweight architecture for gaze-driven object recognition has to be implemented as a wearable device with low power consumption (less than 5.6 W). The algorithmic chain comprises gaze fixations estimation and filtering, generation of candidates, and recognition, with two backbone convolutional neural networks (CNN). The time-consuming parts of the system, such as SIFT (Scale Invariant Feature Transform) detector and the backbone CNN feature extractor, are implemented in FPGA, and a new reduction layer is introduced in the object-recognition CNN to reduce the computational burden. The proposed implementation is compatible with the real-time control of the prosthetic arm.

Postinfectious autoimmune encephalitis with opsoclonus-myoclonus syndrome

Opsoclonus is irregular chaotic eye movements, accompanied by impaired gaze fixation, oscillopsia and associated visual impairment. It is combined with myoclonus of the extremities, trunk, change in gait. It occurs in many pathological conditions, most often in oncological and post-infectious diseases. The rarity and uncommonness of the clinical manifestations of the opsoclonus-myoclonus syndrome, as well as the poor awareness of doctors about this pathology, cause diagnostic difficulties and errors. This report presents the case of a 49-year-old patient, who developed unsteadiness when walking, opsoclonus, myoclonus, startle syndrome, exaggerated startle response 3 weeks after an acute intestinal infection. The diagnostic errors made were analyzed. The diagnosis Post-infection autoimmune encephalitis was proposed and substantiated. Paraneoplastic opsoclonus-myoclonus syndrome was excluded by prospective observation of the patient for 6 years. High efficiency of glucocorticoid treatment was noted.

Reading in Children Who Survived Cerebellar Tumors: Evidence from Eye Movements.

Cerebellar tumors often affect the eye movement centers located in vermis, negatively affecting cognitive development and learning abilities in children. Previous research has established that patients who survived cerebellar tumors tend to demonstrate various saccadic impairments (e.g., hypermetria) and poor gaze stability as compared to healthy controls. The aim of the current study was to evaluate the influence of oculomotor deficits in such patients on reading parameters. A total of 112 children (8–17 y.o.), 65 of whom survived cerebellar tumors, participated in the study. The study design included several oculomotor and reading tasks. Eye movements were recorded every 1/60 s monocularly with an Arrington eye tracker. We observed profound reading impairments in the patients as compared to healthy children, including longer reading time, greater numbers of fixations and regressive saccades, and longer fixation durations. We also found significant correlations between changes in basic oculomotor functions and reading parameters. The patients also demonstrated gaze fixation instability, large number of fixations, and long scanpath reflecting the return of the gaze to the already counted objects. Thus, oculomotor changes caused by cerebellar tumor and its treatment led to disturbances in such neurocognitive activity as reading. Our findings emphasize the necessity of considering these deficits in cerebellar tumor survivors when designing rehabilitation protocols.

How to choose the size of facial areas of interest in interactive eye tracking.

Advances in eye tracking technology have enabled the development of interactive experimental setups to study social attention. Since these setups differ substantially from the eye tracker manufacturer's test conditions, validation is essential with regard to the quality of gaze data and other factors potentially threatening the validity of this signal. In this study, we evaluated the impact of accuracy and areas of interest (AOIs) size on the classification of simulated gaze (fixation) data. We defined AOIs of different sizes using the Limited-Radius Voronoi-Tessellation (LRVT) method, and simulated gaze data for facial target points with varying accuracy. As hypothesized, we found that accuracy and AOI size had strong effects on gaze classification. In addition, these effects were not independent and differed in falsely classified gaze inside AOIs (Type I errors; false alarms) and falsely classified gaze outside the predefined AOIs (Type II errors; misses). Our results indicate that smaller AOIs generally minimize false classifications as long as accuracy is good enough. For studies with lower accuracy, Type II errors can still be compensated to some extent by using larger AOIs, but at the cost of more probable Type I errors. Proper estimation of accuracy is therefore essential for making informed decisions regarding the size of AOIs in eye tracking research.