Eye Movement Behavior Research Articles

Retrospective study of tetanus in 18 dogs-Causes, management, complications, and immunological status.

Tetanus is a severe neurologic disease caused by Clostridium tetani, resulting in spastic paralysis. Canine tetanus is associated with serious complications such as aspiration and a high mortality rate of up to 50%. Medical records of all dogs diagnosed with tetanus over 8 years (2014-2022) were analyzed for severity grade, treatment protocols, nutritional management, and complications, as well as outcome, vaccination, and antibody production in some dogs. No medical records were excluded. Normality was analyzed by the D'Agostino-Pearson test. Parametric, normally distributed data were presented as mean ± standard deviation. Non-parametric, non-normally distributed data were presented as median (m) and range (minimum-maximum). The association between tetanus grade, progression of diseases, and duration of hospitalization was analyzed using the t-test, Mann-Whitney U test, and Kruskal-Wallis test. A P ≤ 0.05 was considered significant. Eighteen dogs were identified. Most affected dogs were classified into severity grade II (66.7%, 12 of 18). Clinical signs deteriorated in 55.6% of dogs (10 of 18). A source was identified in 88.9% of dogs (16 of 18). Nine dogs required surgical wound revision. A percutaneous endoscopic gastropexy tube was placed in 83.3% of dogs (15 of 18) for nutritional support. Medical treatment included metronidazole, methocarbamol, and combinations of different sedatives adapted to the patient's requirements. Tetanus antitoxin was used in 72.2% of dogs (13 of 18) without reported adverse events. The survival rate was 88.9% (16 of 18). Complications, such as hypertension, aspiration pneumonia, and laryngeal spasm occurred in 12 of 18 dogs. Median hospitalization time (8 days; range 0-16 days) was associated with the maximum tetanus severity grade (p = 0.022). Rapid eye movement behavior disorder was observed in 72.2% of dogs (13 of 18). In 5 dogs, antibodies were measured after recovery, and in 4 of 5 dogs, no antibodies were detectable despite generalized tetanus disease. Vaccination with tetanus toxoid was performed in five dogs following the disease. In the present study, the mortality rate was lower than previously reported. Tetanus is still a life-threatening disease, but the prognosis may be good if adequate management and monitoring can be ensured.

85 Predicting Conversion to Mild Cognitive Impairment in Parkinson’s Disease: a Random Forest Machine Learning Model Based on Parkinson’s Progression Markers Initiative Dataset.

Objective:Mild cognitive impairment (MCI) is common in Parkinson’s disease (PD). Recent scientific advances show that MCI in PD could also be impacted by neuropsychiatric symptoms (such as apathy, anxiety, depression), dopaminergic deficiency (more striatal denervation associated with MCI) and certain genotypes such as in APOE E4, MAPT H1 or SNCA C/C carriers. We used a python-based random forest machine-learning algorithm (scikit-learn) in order to evaluate the factors that are mostly involved in the MCI conversion over a 5-year follow-up period.Participants and Methods:Baseline data of healthy individuals and participants with Parkinson’s disease were extracted from the PPMI dataset. All participants also had the evaluations of their cognitive status, neuropsychiatric symptoms (hallucinations, anxiety, apathy, depression, sleepiness, impulse control disorders and rapid eye movement behaviors), dopaminergic uptake (DaT-Scan) and genetic status (APOE, MAPT and SNCA) at baseline and after 5 years. Baseline demographic (age, sex, education years) and clinical values (duration of disease, age of onset) were also included in the model. The algorithm defined (1) the most important variables in predicting MCI, (2) the threshold values to distinguish “converting” vs. “non-converting” subgroups.Results:The algorithm showed that (1) age onset of disease, (2) dopaminergic uptake, (3) age, (4) anxiety, and (5) years of education were the most important factors in predicting MCI over 5 years. Among the factors involved in predicting conversion to MCI, a lower number of years of education associated with lower dopaminergic uptake in the right putamen increased the risk of conversion. Individuals with more years of education are at higher risk of conversion if they have symptoms of depression, anxiety, and lower right striatal dopamine uptake. Other factors that were involved in increasing the risk, were the presence of sleepiness and the presence of rapid eye movement disorders. Interestingly, the genetic factors were of negligible importance and were not considered by the algorithm. Finally, the model showed an accuracy of classification of participants (converters vs. non-converters) of 92.53%.Conclusions:Random forest algorithm shows that (1) depression and anxiety are probably important factors for MCI conversion; (2) years of education influences the conversion; (3) presence of sleepiness and rapid eye movement increases the risk of conversion to MCI. Since the algorithm considers the disease’s age onset, but not the diagnosis of individuals, it would be necessary to generate a model for each group (Healthy on the one hand, Parkinson’s on the other).

A Study on the Evaluation of Brainstem Dysfunction in Rapid Eye Movement Sleep Behavior Disorder Using Video Nystagmography

Background: This study aimed to differentiate video nystagmography (VNG) characteristics, including the video head impulse test (vHIT), in patients with idiopathic rapid eye movement behavior disorder (RBD) from healthy controls, which is considered a precursor to degenerative diseases.Methods: One hundred eighty-five patients underwent overnight polysomnography (PSG) and VNG. Based on overnight PSG, 27 patients with RBD or REM sleep without atonia (RWA) and AHI<15 were categorized into the RBD group, 34 patients with RBD/RWA and AHI≥15 were grouped into the combined group. Sixty patients with AHI≥15 and no RBD/RWA were included in the obstructive sleep apnea (OSA) group, and 64 negative participants were assigned to the control group. In VNG, we measured the gain of vHIT in each canal, with the latency, amplitude, and velocity of horizontal saccades and smooth pursuit. We compared the results between groups using ANOVA, after normalization and adjustment for age and sex.Results: The gain of vHIT in the left horizontal canal was decreased in the RBD group, but it was more pronounced in the OSA group. Elevated gain of the left posterior canal was seen in the RBD group, but technical errors were attributable. The RBD group displayed prolonged latency of saccade on the left side and slowed saccade on the right side, but these were statistically insignificant.Conclusions: The VNG study revealed differences between the sleep disorders, potentially reflecting brainstem function in each disorder. However, these differences lacked statistical significance. We anticipate that significant results could be obtained with more controlled conditions.

Childhood cerebral visual impairment subtype classification based on an extensive versus a limited test battery.

To classify CVI subtypes and compare the added value of an extensive test battery over a limited test battery in subtype classification of cerebral visual impairment (CVI) in children. Seventy-five children with a clinical diagnosis of CVI (median [IQR] age: 9 [7-12] years) were identified from the medical records. The extensive test battery included visual acuity, contrast sensitivity, ocular alignment, eye movement analysis, visual field analysis, optic nerve head evaluation, and evaluation of visual perception. The limited test battery included visual acuity, contrast sensitivity, ocular alignment, and evaluation of visual perception. Principal component analysis (PCA) followed by cluster analysis was done, for both test batteries separately, to determine the optimum subtype classification for CVI. Fifty-one participants with an extensive test battery with mild to moderate visual impairment were included in the main analysis. This resulted in four CVI subtypes for the extensive test battery (subtle characteristics, higher-level visual function deficits, lower-level visual function deficits, and higher- and lower- level visual function deficits) and three CVI subtypes for the limited test battery (subtle characteristics, higher-level visual function deficits, and higher- and lower- level visual function deficits). There were significant differences between the subtypes for 9 out of 10 measures of the extensive and all 4 measures of the limited test battery (p < 0.05). The subtle characteristics subtype (extensive n = 19, limited n = 15) showed near normal lower and higher-level visual functions in both test batteries. The higher-level visual function deficits subtype (extensive n = 18, limited n = 24) showed near normal visual acuity combined with significant visual perceptual deficits in both test batteries; accompanied by visual pathways defects and abnormal eye movement behavior in the extensive test battery. The higher- and lower- level visual function deficits subtype (extensive n = 4, limited n = 12) showed both higher and lower-level visual function deficits in both test batteries, but application of the extensive test battery revealed additional visual pathways defects and abnormal eye movement behavior. The lower-level visual function deficits CVI subtype (extensive n = 10) was a new subtype identified by the extensive test battery. This subtype showed lower-level visual function deficits together with abnormal eye movement measures. This data-driven study has provided meaningful CVI subtype classifications based on the outcomes of various key functional and structural measures in CVI diagnosis. Comparison of the extensive test battery to the limited test battery revealed the added value of an extensive test battery in classifying CVI. The outcomes of this study, therefore, have provided a new direction in the area of CVI classification.

P046 Knowledge of REM Behaviour Disorder Among Sleep Technicians in Australia

Abstract Rapid Eye Movement (REM) Behaviour Disorder (RBD) is a sleep disorder characterized by the absence of muscle paralysis during REM sleep, leading to the enactment of dream content. The accurate identification and management of RBD requires expertise and knowledge among sleep technicians. This study aims to assess the knowledge and awareness of RBD among sleep technicians in Australia. A survey-based investigation was conducted among sleep technicians working in sleep clinics, hospitals, and research centres across Australia. The survey questionnaire consisted of multiple-choice and open-ended questions covering various aspects of RBD, including its definition and diagnostic criteria as well as their knowledge, training and lab practices. The survey was distributed electronically, and responses were collected anonymously. Preliminary findings from a sample of 30 sleep technicians revealed a significant variability in knowledge regarding RBD. While 68% of participants demonstrated a solid understanding of RBD, 22% displayed limited knowledge, and 10% had minimal awareness of the disorder. Interestingly, the majority of participants reported that their workplace investigated patients with potential RBD symptoms but also the majority reported that they lacked the knowledge and resources to detect the condition appropriately. These findings emphasize the need for targeted educational interventions and training programs to enhance the knowledge and competence of sleep technicians in identifying and managing RBD. By addressing these knowledge gaps, sleep technicians can play a vital role in early detection, timely referral, and appropriate management of RBD, thereby improving patient outcomes and quality of life.

A common cause for nystagmus in different congenital stationary night blindness mouse models.

In Nyxnob mice, a model for congenital nystagmus associated with congenital stationary night blindness (CSNB), synchronous oscillating retinal ganglion cells (RGCs) lead to oscillatory eye movements, i.e. nystagmus. Given the specific expression of mGluR6 and Cav 1.4 in the photoreceptor to bipolar cell synapses, as well as their clinical association with CSNB, we hypothesize that Grm6nob3 and Cav 1.4-KO mutants show, like the Nyxnob mouse, oscillations in both their RGC activity and eye movements. Using multi-electrode array recordings of RGCs and measurements of the eye movements, we demonstrate that Grm6nob3 and Cav 1.4-KO mice also show oscillations of their RGCs as well as a nystagmus. Interestingly, the preferred frequencies of RGC activity as well as the eye movement oscillations of the Grm6nob3 , Cav 1.4-KO and Nyxnob mice differ among mutants, but the neuronal activity and eye movement behaviour within a strain remain aligned in the same frequency domain. Model simulations indicate that mutations affecting the photoreceptor-bipolar cell synapse can form a common cause of the nystagmus of CSNB by driving oscillations in RGCs via AII amacrine cells. KEY POINTS: In Nyxnob mice, a model for congenital nystagmus associated with congenital stationary night blindness (CSNB), their oscillatory eye movements (i.e. nystagmus) are caused by synchronous oscillating retinal ganglion cells. Here we show that the same mechanism applies for two other CSNB mouse models - Grm6nob3 and Cav 1.4-KO mice. We propose that the retinal ganglion cell oscillations originate in the AII amacrine cells. Model simulations show that by only changing the input to ON-bipolar cells, all phenotypical differences between the various genetic mouse models can be reproduced.

Eye-tracking evidence from attachment structures favors a serial model of discourse–sentence interactivity

ABSTRACT Many psycholinguistic studies examine how people parse sentences in isolation; however, years of work in discourse processing have shown that sentence-level interpretations are influenced at some stage by discourse-level information. Evidence over the past 20 years remains mixed as to the temporal dynamics of such top-down interactions. In particular, dynamic accounts where readers use the discourse model to generate expectations for certain grammatical structures before and during parsing differ from serial accounts where an algorithmic first-pass processing mechanism precedes integration of sentence material into the discourse model. To test between these two theories, the current study investigates eye-movement behaviors when reading temporarily ambiguous attachment structures following discourses with biases either matching, mismatching, or neutral with respect to the attachment resolution. No evidence was found suggesting readers systematically use discourse information to generate structural expectations, in line with serial accounts of processing at the sentence–discourse interface. Scanpath analyses further highlight the confirmatory nature of rereading when participants encounter discourse continuations that do not fit with prior contexts.

Understanding representations of uncertainty, an eye-tracking study – Part 2: The effect of expertise

Abstract. As the ability to make predictions regarding uncertainty information representing natural hazards increases, an important question for those designing and communicating hazard forecasts is how visualizations of uncertainty influence understanding amongst the intended, potentially varied, target audiences. End-users have a wide range of differing expertise and backgrounds, possibly influencing the decision-making process they undertake for a given forecast presentation. Our previous, Part 1 study (Mulder et al., 2023) examined how the presentation of uncertainty information influenced end-user decision making. Here, we shift the focus to examine the decisions and reactions of participants with differing areas of expertise (meteorology, psychology, and graphic-communication students) when presented with varied hypothetical forecast representations (boxplot, fan plot, or spaghetti plot with and without median lines) using the same eye-tracking methods and experiments. Participants made decisions about a fictional scenario involving the choices between ships of different sizes in the face of varying ice thickness forecasts. Eye movements to the graph area and key and how they changed over time (early, intermediate, and later viewing periods) were examined. More fixations (maintained gaze on one location) and more fixation time were spent on the graph and key during early and intermediate periods of viewing, particularly for boxplots and fan plots. The inclusion of median lines led to less fixations being made on all graph types during early and intermediate viewing periods. No difference in eye movement behaviour was found due to expertise; however, those with greater expertise were more accurate in their decisions, particularly during more difficult scenarios. Where scientific producers seek to draw users to the central estimate, an anchoring line can significantly reduce cognitive load, leading both experts and non-experts to make more rational decisions. When asking users to consider extreme scenarios or uncertainty, different prior expertise can lead to significantly different cognitive loads for processing information, with an impact on one's ability to make appropriate decisions.

How task instruction influences the performance and the text reading pattern in case of inconsistent compare problems in primary school.

"Compare word problems are quite difficult for primary school students, especially inconsistent ones when the relational term from the problem text is not consistent with the arithmetic operation required for the solution. The present study investigates the effect of different task instructions on successfulness in solving inconsistent compare word problems and in the reading pattern of the text of these problems. Therefore, in this study eye-tracking was used to monitor participants eye movements while reading and solving compare word problems. Fifty-six 4th graders’ eye-movement behavior and responses were collected to analyze the fixation time and fixation number on different data from the text of the tasks and the solution time on each task. In the test inconsistent compared problems were given requiring the use of multiplication/division operations. The problems were divided into three groups with different task instructions. In the first group of problems the requirement was to solve the problems, pupils could freely concentrate on the text elements they wanted as the text of the problem was classically given. In the second case students were forced to spend more time focusing on the context of the problem as they first got the text of the problem with symbols instead of numbers. In the case of the third group of problems, pupils had to create the graphical representation of the word problem considering the value of the given variable and the relation between the two variables. The results show that the instruction type influenced both performance and reading pattern. When students are forced to spend more time reading the entire text (problems given first with symbols), the solution success rate is higher. Graphical representation of the problem’s data also contributes to a better performance. There are also differences in percentages of reading times spent on fixation different key elements of the text or different sentences of the problem. The key element fixated for a higher percentage of time depends on the type of instruction."

How task instruction influences the performance and the text reading pattern in case of inconsistent compare problems in primary school.

"Compare word problems are quite difficult for primary school students, especially inconsistent ones when the relational term from the problem text is not consistent with the arithmetic operation required for the solution. The present study investigates the effect of different task instructions on successfulness in solving inconsistent compare word problems and in the reading pattern of the text of these problems. Therefore, in this study eye-tracking was used to monitor participants eye movements while reading and solving compare word problems. Fifty-six 4th graders’ eye-movement behavior and responses were collected to analyze the fixation time and fixation number on different data from the text of the tasks and the solution time on each task. In the test inconsistent compared problems were given requiring the use of multiplication/division operations. The problems were divided into three groups with different task instructions. In the first group of problems the requirement was to solve the problems, pupils could freely concentrate on the text elements they wanted as the text of the problem was classically given. In the second case students were forced to spend more time focusing on the context of the problem as they first got the text of the problem with symbols instead of numbers. In the case of the third group of problems, pupils had to create the graphical representation of the word problem considering the value of the given variable and the relation between the two variables. The results show that the instruction type influenced both performance and reading pattern. When students are forced to spend more time reading the entire text (problems given first with symbols), the solution success rate is higher. Graphical representation of the problem’s data also contributes to a better performance. There are also differences in percentages of reading times spent on fixation different key elements of the text or different sentences of the problem. The key element fixated for a higher percentage of time depends on the type of instruction."

Minor hallucinations in Parkinson's disease with probable rapid eye movement sleep behavior disorder.

Rapid eye movement sleep behavior disorder (RBD) and minor hallucinations (MHs) are prevalent nonmotor symptoms in Parkinson's disease (PD). The purpose of this study was to explore the association of MHs in PD patients with probable RBD (pRBD). This cross-sectional study included 291 patients diagnosed with PD. Patients who scored 6 or higher on the Rapid Eye Movement Behavior Disorder (RBD) Screening Questionnaire were defined as pRBD. A comprehensive evaluation was performed for all patients, including the collection of demographic information, clinical assessment, and MH features. Among the 291 PD patients, 69 (23.7%) had pRBD. MHs were observed in 35 (50.7%) patients with pRBD, significantly higher than 29.7% in patients without RBD (p = 0.015). The main type of MHs in pRBD was presence hallucinations with variable content. Patients with pRBD and MHs tended to be older, had a longer disease duration, and were more likely to take levodopa or dopamine-receptor agonists. Besides, the pRBD with MHs group had higher scores on the Nonmotor Symptoms Questionnaire (NMS-Quest) and Hamilton Anxiety Scale (HAMA). Binary logistic regression analysis revealed that longer disease duration and higher NMS-Quest scores were associated with MHs in PD patients with pRBD. A high prevalence of MHs was observed in PD patients with pRBD. The main type of MHs in pRBD was presence hallucinations. MHs in PD with RBD are mainly associated with disease duration and severity of nonmotor symptoms. These findings provide new insights into the interaction between MHs and RBD.

ETMT: A Tool for Eye-Tracking-Based Trail-Making Test to Detect Cognitive Impairment.

The growing number of people with cognitive impairment will significantly increase healthcare demand. Screening tools are crucial for detecting cognitive impairment due to a shortage of mental health experts aiming to improve the quality of life for those living with this condition. Eye tracking is a powerful tool that can provide deeper insights into human behavior and inner cognitive processes. The proposed Eye-Tracking-Based Trail-Making Test, ETMT, is a screening tool for monitoring a person's cognitive function. The proposed system utilizes a fuzzy-inference system as an integral part of its framework to calculate comprehensive scores assessing visual search speed and focused attention. By employing an adaptive neuro-fuzzy-inference system, the tool provides an overall cognitive-impairment score, allowing psychologists to assess and quantify the extent of cognitive decline or impairment in their patients. The ETMT model offers a comprehensive understanding of cognitive abilities and identifies potential deficits in various domains. The results indicate that the ETMT model is a potential tool for evaluating cognitive impairment and can capture significant changes in eye movement behavior associated with cognitive impairment. It provides a convenient and affordable diagnosis, prioritizing healthcare resources for severe conditions while enhancing feedback to practitioners.

How Vegetation Colorization Design Affects Urban Forest Aesthetic Preference and Visual Attention: An Eye-Tracking Study

The enhancement of the urban forest landscape through vegetation colorization has emerged as a continuous concern for urban managers in southern Chinese cities. However, the understanding of how designers can effectively select the appropriate form and intensity of colorization design to align with users’ aesthetic preferences remains limited. The process of visual perception is closely intertwined with eye movements. Employing visualization techniques, this research aims to investigate the impact of colorization design on aesthetic benefits and eye movements in urban forests, considering four intensities (slight, low, medium, and high) and three forms (aggregate, homogeneous, and random). A total of 183 participants (with an average age of 23.5 ± 2.5 years) were randomly assigned to three groups to assess the aesthetics score, while eye-tracking devices were utilized to record eye movement behaviors. The outcomes indicate that a homogeneous design form and a moderate intensity of landscaping yield higher scenic benefits for urban forests. In the case of canopy landscape, both the form and intensity of landscaping have a significant influence on urban forest aesthetics. The HCI with aggregate form showed the best marginal effect (1.313). In contrast, MCI showed the best marginal effect when the design form was random and homogeneous (1.438, 1.308). Furthermore, although the form and intensity of the colorization design significantly affect eye exploration, the perception of landscape aesthetics does not correlate with eye movements. These findings provide valuable insights for design policies aimed at promoting the urban forest landscape, while also contributing to the enrichment of research in landscape perception studies employing eye-tracking technology.

Quantitative Model Study of the Psychological Recovery Benefit of Landscape Environment Based on Eye Movement Tracking Technology

From the perspective of landscape and human health, we use the Self-Rating Restoration Scale (SRRS) as a tool to explore the mental health restoration benefits brought by a landscape environment to individuals and explore the characteristics of individual movement behavior when viewing the landscape through the eye movement tracking technology. We selected average blink duration, average gaze length, average saccade amplitude, blink number, number of fixation points, saccade number, and average pupil diameter as experimental indicators for data monitoring. Based on the eye movement heat map obtained by data visualization processing and the results of correlation analysis, we summarized the eye movement behavior characteristics of individuals when viewing the restorative landscape. We try to construct a quantitative evaluation model of the landscape mental recovery benefit with the objective eye movement index as the independent variable through the method of curve estimation. The study results show that individual eye movement behavior is related to the landscape type and the level of psychological recovery is also different. (1)The more singular that the constituent elements are, the more widespread and concentrated the regional distribution of individual attention areas, and the relative psychological recovery benefit is relatively weak. The more complex that the constituent elements are, the more scattered and smaller the individual interest area, and the psychological recovery benefit is better. Brightly colored, dynamic landscapes are easier to form areas of interest to improve the psychological response to the human body. (2) The psychological recovery benefit of the landscape is directly proportional to the changing trend of the average blink duration, number of fixation points, and number of saccades and is inversely proportional to the changing trend of the average gaze length. (3) The objective eye movement index of average blink duration can quantitatively predict the psychological recovery benefit value of the landscape environment. The number of fixation points, the number of saccades, and the average fixation length could predict the psychological recovery benefits of the landscape, while the other indicators had no prediction effect.

Scanpath Regularity as an Index of Reading Comprehension

ABSTRACT Purpose Recent research on the potential of using eye-tracking to measure reading comprehension ability suggests that the relationship between standard eye-tracking measures and reading comprehension is influenced by differences in task demands between comprehension assessments. We compared standard eye-tracking measures and scanpath regularity as predictors of reading comprehension scores. Method We used a dataset in which 79 participants (mean age: 22 years, 82% females, 76% monolingual English speakers) were administered three widely-used reading comprehension assessments with varying task demands while their eye movements were monitored: the York Assessment of Reading for Comprehension; (YARC), the Gray Oral Reading Test; (GORT-5), and the sentence comprehension subtest of the Wide Range Achievement Test; (WRAT-4). Results Results showed that scanpath regularity measures, similarly to standard eye-tracking measures, were influenced by differences in task demands between the three tests. Nevertheless, both types of eye-tracking measures made unique contributions as predictors of comprehension and the best set of predictors included both standard eye-tracking measures and at least one scanpath measure across tests. Conclusion The results provide evidence that scanpaths capture differences in eye-movement patterns missed by standard eye-tracking measures. Overall, the results highlight the effect of task demands on eye-movement behavior and suggest that reading goals and task demands need to be considered when interpreting eye-tracking data.

An updating-based working memory load alters the dynamics of eye movements but not their spatial extent during free viewing of natural scenes

The relationship between spatial deployments of attention and working memory load is an important topic of study, with clear implications for real-world tasks such as driving. Previous research has generally shown that attentional breadth broadens under higher load, while exploratory eye-movement behaviour also appears to change with increasing load. However, relatively little research has compared the effects of working memory load on different kinds of spatial deployment, especially in conditions that require updating of the contents of working memory rather than simple retrieval. The present study undertook such a comparison by measuring participants’ attentional breadth (via an undirected Navon task) and their exploratory eye-movement behaviour (a free-viewing recall task) under low and high updating working memory loads. While spatial aspects of task performance (attentional breadth, and peripheral extent of image exploration in the free-viewing task) were unaffected by the load manipulation, the exploratory dynamics of the free-viewing task (including fixation durations and scan-path lengths) changed under increasing load. These findings suggest that temporal dynamics, rather than the spatial extent of exploration, are the primary mechanism affected by working memory load during the spatial deployment of attention. Further, individual differences in exploratory behaviour were observed on the free-viewing task: all metrics were highly correlated across working memory load blocks. These findings suggest a need for further investigation of individual differences in eye-movement behaviour; potential factors associated with these individual differences, including working memory capacity and persistence versus flexibility orientations, are discussed.

The reduction of saccadic inhibition by distractor repetition.

When visual distractors are presented far from the goal of an impending voluntary saccadic eye movement, saccade execution will occur less frequently about 90 ms after distractor appearance, a phenomenon known as saccadic inhibition. However, it is also known that neural responses in visual and visuomotor areas of the brain will be attenuated if a visual stimulus appears several times in the same location in rapid succession. In particular, such visual adaptation can affect neurons in the mammalian superior colliculus (SC). As the SC is known to be intimately involved in the production of saccadic eye movements, and thus perhaps in saccadic inhibition, we used a memory-guided saccade task to test whether saccadic inhibition in humans would diminish if a distractor appeared several times in quick succession. We found that distractor repetition reduced saccadic inhibition considerably when distractors appeared opposite in space to the goal of the impending saccade. In addition, when three distractors appeared in quick succession but in different, spatially disparate locations, with only the final distractor appearing opposite the saccade goal, saccadic inhibition was reduced by an intermediate level, suggesting that its reduction due to distractor inhibition spatially generalizes. This suggests that distractor suppression can help reduce the impact that suddenly appearing visual stimuli have on purposive eye movement behavior.NEW & NOTEWORTHY This work combines approaches studying saccadic inhibition and visual adaptation to demonstrate that saccadic inhibition is largely eliminated with stimulus repetition. This is likely to be the largest demonstrated effect of visual stimulus context on saccadic inhibition. It also provides evidence for the existence of a mechanism that acts to suppress the effect of frequently appearing visual stimuli on purposive eye movement behavior in dynamic visual environments.

A perceptual field test in object experts using gaze-contingent eye tracking

A hallmark of expert object recognition is rapid and accurate subordinate-category recognition of visually homogenous objects. However, the perceptual strategies by which expert recognition is achieved is less known. The current study investigated whether visual expertise changes observers’ perceptual field (e.g., their ability to use information away from fixation for recognition) for objects in their domain of expertise, using a gaze-contingent eye-tracking paradigm. In the current study, bird experts and novices were presented with two bird images sequentially, and their task was to determine whether the two images were of the same species (e.g., two different song sparrows) or different species (e.g., song sparrow and chipping sparrow). The first study bird image was presented in full view. The second test bird image was presented fully visible (full-view), restricted to a circular window centered on gaze position (central-view), or restricted to image regions beyond a circular mask centered on gaze position (peripheral-view). While experts and novices did not differ in their eye-movement behavior, experts’ performance on the discrimination task for the fastest responses was less impaired than novices in the peripheral-view condition. Thus, the experts used peripheral information to a greater extent than novices, indicating that the experts have a wider perceptual field to support their speeded subordinate recognition.

CAPSCNet: A novel scattering network for automated identification of phasic cyclic alternating patterns of human sleep using multivariate EEG signals

The Cyclic Alternating Pattern (CAP) can be considered a physiological marker of sleep instability. The CAP can examine various sleep-related disorders. Certain short events (A and B phases) manifest related to a specific physiological process or pathology during non-rapid eye movement (NREM) sleep. These phases unexpectedly modify EEG oscillations; hence, manual detection is challenging. Therefore, it is highly desirable to have an automated system for detecting the A-phases (AP).Deep convolution neural networks (CNN) have shown high performance in various healthcare applications. A variant of the deep neural network called the Wavelet Scattering Network (WSN) has been used to overcome the specific limitations of CNN, such as the need for a large amount of data to train the model. WSN is an optimized network that can learn features that help discriminate patterns hidden inside signals. Also, WSNs are invariant to local perturbations, making the network significantly more reliable and effective. It can also help improve performance on tasks where data is minimal. In this study, we proposed a novel WSN-based CAPSCNet to automatically detect AP using EEG signals. Seven dataset variants of cyclic alternating pattern (CAP) sleep cohort is employed for this study. Two electroencephalograms (EEG) derivations, namely: C4-A1 and F4-C4, are used to develop the CAPSCNet. The model is examined using healthy subjects and patients tormented by six different sleep disorders, namely: sleep-disordered breathing (SDB), insomnia, nocturnal frontal lobe epilepsy (NFLE), narcolepsy, periodic leg movement disorder (PLM) and rapid eye movement behavior disorder (RBD) subjects. Several different machine-learning algorithms were used to classify the features obtained from the WSN. The proposed CAPSCNet has achieved the highest average classification accuracy of 83.4% using a trilayered neural network classifier for the healthy data variant. The proposed CAPSCNet is efficient and computationally faster.

Driver distraction and in-vehicle interventions: A driving simulator study on visual attention and driving performance

Driving simulator studies are popular means to investigate driving behaviour in a controlled environment and test safety-critical events that would otherwise not be possible in real-world driving conditions. While several factors affect driving performance, driving distraction has been emphasised as a safety-critical issue across the globe. In this context, this study explores the impact of distraction imposed by mobile phone usage, i.e., writing and reading text messages, on driver behaviour. As part of the greater i-DREAMS project, this study uses a car driving simulator experimental design in Germany to investigate driver behaviour under various conditions: (I) monitoring scenario representing normal driving conditions, (II) intervention scenario in which drivers receive fixed timing in-vehicle intervention in case of unsafe driving manoeuvres, and (III) distraction scenario in which drivers receive in-vehicle interventions based on task completion capability, where mobile phone distraction is imposed. Besides, eye-tracking glasses are used to further explore drivers’ attention allocation and eye movement behaviour. This research focuses on driver response to risky traffic events (i.e., potential pedestrian collisions, and tailgating) and the impact of distraction on driving performance, by analysing a set of eye movement and driving performance measures of 58 participants. The results reveal a significant change in drivers’ gaze patterns during the distraction drives with significantly higher gaze points towards the i-DREAMS intervention display (the utilised advanced driver assistance systems in this study). The overall statistical analysis of driving performance measures suggests nearly similar impacts on driver behaviour during distraction drives; a higher deviation of lateral positioning was noted irrespective of the event risk levels and lower longitudinal acceleration rates were observed for pedestrian collisions and non-critical events during distracted driving.