Eye Tracking Test Research Articles

Voluntary Attention Assessing Tests in Children with Neurodevelopmental Disorders Using Eye Tracking.

Background/Objectives: The development of techniques for assessing cognitive functions using eye tracking is particularly important for children with developmental disabilities. In this paper, we present pilot results from the validation of two methods for assessing voluntary attention based on eye tracking. Methods: The study involved 80 children aged 3 to 8 years with neurodevelopmental disorders. Children performed two eye-tracking tests in which they had to 'catch' a stimulus by looking at it. They also completed the Attention Sustained subtest of the Leiter-3 International Performance Scale. In the first test, the stimuli were presented at different locations on the screen in subtests with stimuli onset asynchrony of 2 s and 1 s. A translucent blue marker marked the position of the gaze on the screen. The number of trials in which the gaze marker approached the stimulus was determined. In the second test, the location of the stimuli on the screen was changed based on gaze fixation in the ROI area. The time taken to complete the task was evaluated. Results: The results of both eye-tracking tests showed significant correlations with scores on the Attention Sustained Leiter-3 subtest and significant test-retest reliability. Conclusions: The results indicate that the present eye-tracking tests can be used for assessing voluntary attention in children with some neurodevelopmental disorders, and further research is warranted to assess the feasibility of these tests for a broader range of developmental disorders. Our findings could have practical implications for the early intervention and ongoing monitoring of attention-related issues.

Oculomotor Behaviour in Individuals with Long COVID-19

Objective To determine, the impact of long COVID-19 on oculomotor behaviour. Design A case–control study. Setting Spanish Association of Persistent COVID. Participant Participants were 75 cases (64 women, 11 men, mean age 46.4 years ±8.9) and 42 controls (22 women, 20 men, mean age 53.5 years ±13.13). Intervention An eye-tracking test based on visual search paradigm and the Adult Developmental Eye Movement Test were used to evaluate the participants. Main measures The primary outcomes in the Adult Developmental Eye Movement Test were horizontal reading time, vertical reading time, and their ratio. And for the eye-tracking test the time to find the target, the duration, and the number of eye fixations. Results In cases and controls, eye movement test results were horizontal(Hadj) reading time 74.2 ± 22.7 s vs 52.0 ± 6.1 s (p < .0001); vertical(Vadj) reading time 67.6 ± 17.8 s vs 50.4 ± 6.9 s (p < .0001); Hadj/Vadj ratio 0.9 ± 0.1 vs 1.0 ± 0 (p = .0032), respectively; and eye-tracking test results were fixation number 11.3 ± 3.07 vs 3.51 ± 2.57 (p < .0001); fixation duration 2.01 ± 0.79 s vs 1.5 ± 0.4 s (p = .0013), and time to find target 24.5 ± 8.0 vs 18 ± 9.4 (p = .0034), respectively. Conclusions Data showed a lower performance in oculomotor behaviour in people with long COVID-19, compared to healthy individuals. It cannot be affirmed an ocular musculature dysfunction; the differentiated behaviour could be associated to cognitive alterations affected in these people. Both tests used could be an useful tool for the clinical assessment of these participants. Further studies are needed to explore the utility of these procedures.

Eye Tracking-Based Characterization of Fixations during Reading in Children with Neurodevelopmental Disorders.

An efficient mode of evaluation for eye movements is the use of objective eye tracking systems combined with subjective tests (NSUCO or DEM), which are easily applicable across all age groups and in eye care clinical settings. The objective of this study was to characterize fixations during reading in two groups: a group of children with neurodevelopmental disorders (NDDG, 24 children, age: 6-12 years) and a group of children with oculomotor anomalies but without NDD (OAG, 24 children, age: 6-12 years). The results obtained were compared with those from a control group (CG, 20 children, age: 6-12 years). Specifically, the outcomes obtained with two subjective score systems, the Northeastern State University College of Optometry's Oculomotor (NSUCO) test and the Developmental Eye Movement (DEM) test, were compared with the objective analysis obtained through a commercially available eye tracker (Tobii Eye X, Tobii, Stockholm, Sweden). Specialized analysis software, namely Clinical Eye Tracker 2020 (Thomson Software Solutions, Welham Green, UK), was used. It was found that children with NDD had impaired oculomotor skills. A higher number of regressions, more fixations, and longer durations of fixations appear to be characteristic signs of this population group. Additionally, children with NDD took longer to complete the DEM test, as well as exhibiting more errors. The use of objective videoculographic systems for eye tracking and subjective tests like the NSUCO or DEM are good tools to assess saccadic movements, allowing the detection of oculomotor abnormalities in children with NDD.

Eye-Tracking Biomarkers and Autism Diagnosis in Primary Care

Finding effective and scalable solutions to address diagnostic delays and disparities in autism is a public health imperative. Approaches that integrate eye-tracking biomarkers into tiered community-based models of autism evaluation hold promise for addressing this problem. To determine whether a battery of eye-tracking biomarkers can reliably differentiate young children with and without autism in a community-referred sample collected during clinical evaluation in the primary care setting and to evaluate whether combining eye-tracking biomarkers with primary care practitioner (PCP) diagnosis and diagnostic certainty is associated with diagnostic outcome. Early Autism Evaluation (EAE) Hub system PCPs referred a consecutive sample of children to this prospective diagnostic study for blinded eye-tracking index test and follow-up expert evaluation from June 7, 2019, to September 23, 2022. Participants included 146 children (aged 14-48 months) consecutively referred by 7 EAE Hubs. Of 154 children enrolled, 146 provided usable data for at least 1 eye-tracking measure. The primary outcomes were sensitivity and specificity of a composite eye-tracking (ie, index) test, which was a consolidated measure based on significant eye-tracking indices, compared with reference standard expert clinical autism diagnosis. Secondary outcome measures were sensitivity and specificity of an integrated approach using an index test and PCP diagnosis and certainty. Among 146 children (mean [SD] age, 2.6 [0.6] years; 104 [71%] male; 21 [14%] Hispanic or Latine and 96 [66%] non-Latine White; 102 [70%] with a reference standard autism diagnosis), 113 (77%) had concordant autism outcomes between the index (composite biomarker) and reference outcomes, with 77.5% sensitivity (95% CI, 68.4%-84.5%) and 77.3% specificity (95% CI, 63.0%-87.2%). When index diagnosis was based on the combination of a composite biomarker, PCP diagnosis, and diagnostic certainty, outcomes were concordant with reference standard for 114 of 127 cases (90%) with a sensitivity of 90.7% (95% CI, 83.3%-95.0%) and a specificity of 86.7% (95% CI, 70.3%-94.7%). In this prospective diagnostic study, a composite eye-tracking biomarker was associated with a best-estimate clinical diagnosis of autism, and an integrated diagnostic model including PCP diagnosis and diagnostic certainty demonstrated improved sensitivity and specificity. These findings suggest that equipping PCPs with a multimethod diagnostic approach has the potential to substantially improve access to timely, accurate diagnosis in local communities.

DIARY STUDY OF THE USER EXPERIENCE OF THE ATTENTION BIASTEST

This study evaluates a webcam-based eye-tracking test of Attention Bias (AB) conducted on the Anima platform using diary study methodology. The AB paradigm measures variations in attentional response to emotional stimuli of different valence, providing a methodological framework for evaluating psychological states. We developed the ASMQ questionnaire to complement the eye-tracking data. Linear mixed models explored the relationships between diary data and eye-tracking measures, clarifying the alignment between AB test metrics and subjective feelings. Correlation analysis affirmed the AB test’s concurrent validity. Psychometric evaluations using EFA, CFA, and reliability metrics demonstrated a two- factor structure for the ASMQ, explaining 49.7% of the variance and confirming its internal consistency.

Usability of eye trackers as tools for designers of anastylosis

Eye trackers are more and more often employed by scientists willing to learn more about how cultural heritage is perceived. However, designers very seldom make use of this technology, primarily perhaps due to its expensive and time-consuming nature. By choosing not to employ eye trackers they limit themselves to their own ideas and choices, at the same time forfeiting all the potential advantages of social consultations with non-professionals. One can easily imagine that their work and its effects would only benefit should a way be found to make eye-tracking tests more logistically and financially feasible or if another measure was established that would make it possible to learn the visual reactions of regular people. This paper focuses on perception of anastylosis. There are numerous types of damaged structures that get reassembled and multiple ways of doing that. While most doctrinal documents assert that the original object and the added elements should be easily distinguishable, the two solutions, most often chosen by designers is to make the cavity fillings differ in either texture or luminance from the original material. It is obvious that this results in a large range of solutions to choose from – from shallow indentations in the stone surface to deep ones, from stone just a shade brighter than the original to a distinct cream-white one. Since it is impossible to test all the possible variations using eye trackers, the authors of this paper tried a different approach. Eleven different virtual images were prepared of the same reassembled ionic column. They varied in the level of modifications applied to either the texture or the luminance of the cavity fillings. The entire set of eleven stimuli was then shown to a group of professionals in the field of architecture and/or conservation of monuments. They were asked to choose the best stimuli, that is those that facilitate the differentiation of the old and new parts of the structure by non-professionals. Thus, reduced set of three stimuli was then used in an eye-tracking tests involving over 100 participants. The eye-tracking data, combined with the results of previous research on the perception of anastylosis allowed the authors to formulate several conclusions. It turned out that the images selected by the professionals were far from those that would potentially stimulate and help non-professionals the most. However, the obtained information allowed formulating a few basic guidelines as to the use of differences in texture and luminance in anastylosis. It also made it possible to find a financially and logistically feasible alternative to the demanding eye-tracking tests when it comes to introducing social consultations into the designing process.

Semantic Network Development in L2 Spanish and Its Impact on Processing Skills: A Multisession Eye-Tracking Study

The goal of this project was to explore how different types of vocabulary exposure shape the connections formed in the L2 lexicon and how these, in turn, affect L2 language processing. During L2 acquisition, words are often presented in thematic lists (e.g., food), favoring a lexicon organized by shared features (burger-hot dog). However, thematic lists offer only a partial picture of how words interconnect. For example, beer and football do not share any features and do not belong strictly to the same theme (food and sports, respectively); still, they co-occur frequently and are associated in the lexicon. A multisession training study and visual world eye-tracking tests were conducted to assess how different types of vocabulary exposure impact L2 processing. Intermediate L2 Spanish learners were trained under one of two conditions, thematic lists (TL, as in textbooks) or words presented in visual scenes (VS) with vocabulary related by co-occurrence. The VS group showed significant changes in their gaze patterns, resembling the naturalistic exposure baseline group (native speakers), more than the TL group. The results are interpreted in light of the anticipatory processing literature and the strength of representations as a result of naturalistic vs. formal exposure to L2 vocabulary.

Automated Eye Tracking Enables Saccade Performance Evaluation of Patients with Concussion History.

Automated eye tracking could be used to evaluate saccade performance of patients with concussion history, providing quantitative insights about the degree of oculomotor impairment and potential vision rehabilitation strategies for this patient population. To evaluate the saccade performance of patients with concussion history based on automated eye-tracking test results. We conducted a retrospective study of patients with concussion history, primarily from sports participation, who underwent oculomotor testing based on an eye-tracking technology at the Duke Eye Center vision rehabilitation clinic between June 30, 2017, and January 10, 2022. Patients' saccade test results were reviewed, including saccade fixation and saccade speed/accuracy ratio. The outcomes were compared with age-matched normative population data derived from healthy individuals. Multiple linear regression analyses were performed to identify factors associated with saccade performance among patients with concussion history. On hundred fifteen patients with concussion history were included in the study. Patients with concussion, on average, had fewer fixations on self-paced horizontal and vertical saccade tests and lower horizontal and vertical saccade speed/accuracy ratios compared with normative ranges. Among patients with concussion history, multiple linear regression analyses showed that older age was associated with fewer fixations on horizontal and vertical saccade tests, whereas male sex was associated with more fixations on horizontal and vertical saccade tests (all P < .01). In addition, older age was associated with lower horizontal saccade speed/accuracy ratio, after adjusting for sex, number of concussion(s), and time from most recent concussion to oculomotor testing ( P < .001). Patients with concussion history had lower saccade performance based on eye tracking compared with healthy individuals. We additionally identified risk factors for lower saccade performance among patients with concussion history. These findings support the use of saccade test results as biomarkers for concussion and have implications for post-concussion rehabilitation strategies.

TREYESCAN: configuration of an eye tracking test for the measurement of compensatory eye movements in patients with visual field defects

The Traffic Eye Scanning and Compensation Analyzer (TREYESCAN) is introduced as an innovative eye tracking test designed to measure compensatory eye movements in individuals with visual field defects. The primary objective of the test is to quantitatively assess and analyze the compensatory eye movements employed by patients with visual field defects while viewing videos of various traffic scenes from the viewpoint of a driver of a passenger car. The filming process involved capturing a wide range of driving conditions and hazards, aiming to replicate real-world scenarios. Specific dynamic areas of interest within these scenes were selected and assessed by a panel of experts on medical and practical fitness to drive. Pilot measurements were conducted on a sample of 20 normally-sighted individuals during two different measurement sessions. The results provide valuable insights into how individuals without visual impairment view the dynamic scenes presented in the test. Moving forward, the TREYESCAN will be used in a case–control study involving glaucoma patients and control subjects, with the goal of further investigating and understanding the mechanisms employed by individuals with glaucoma to compensate for their visual field defects.

Investigation of Web-Based Eye-Tracking System Performance under Different Lighting Conditions for Neuromarketing

The increasing popularity of neuromarketing has led to the emergence of various measurement methods, such as webcam-based eye-tracking technology. Webcam-based eye-tracking technology is noteworthy not only for its use in laboratories but also for its ability to be applied to participants online in their natural environments through a link. However, the complexity of e-commerce interfaces necessitates high performance in eye-tracking methods. This complexity and the applicability of webcam-based eye-tracking technology in various environments have raised research questions about how its performance changes depending on the type and location of lighting. To answer these questions, experiments were conducted with 30 users in two different experimental environments illuminated by artificial and natural methods, with the lighting from the left, right, and front. Participants were asked to focus on targets located in specially prepared graphics for the experiment. In the heatmaps obtained in the eye-tracking tests, the distance and angular difference between the focal point and the target point were measured using the polar coordinate system. The findings indicate that measurements taken with lighting coming from the center were more efficient in both natural and artificial lighting types and measurements taken under natural lighting performed 24% better than artificial ones. Web camera-based eye-tracking technology is a promising method. However, detailed statistical analyses have demonstrated that for complex interfaces like e-commerce, the position and type of lighting are crucial parameters.

Machine learning-based early diagnosis of autism according to eye movements of real and artificial faces scanning.

Studies on eye movements found that children with autism spectrum disorder (ASD) had abnormal gaze behavior to social stimuli. The current study aimed to investigate whether their eye movement patterns in relation to cartoon characters or real people could be useful in identifying ASD children. Eye-tracking tests based on videos of cartoon characters and real people were performed for ASD and typically developing (TD) children aged between 12 and 60 months. A three-level hierarchical structure including participants, events, and areas of interest was used to arrange the data obtained from eye-tracking tests. Random forest was adopted as the feature selection tool and classifier, and the flattened vectors and diagnostic information were used as features and labels. A logistic regression was used to evaluate the impact of the most important features. A total of 161 children (117 ASD and 44 TD) with a mean age of 39.70 ± 12.27 months were recruited. The overall accuracy, precision, and recall of the model were 0.73, 0.73, and 0.75, respectively. Attention to human-related elements was positively related to the diagnosis of ASD, while fixation time for cartoons was negatively related to the diagnosis. Using eye-tracking techniques with machine learning algorithms might be promising for identifying ASD. The value of artificial faces, such as cartoon characters, in the field of ASD diagnosis and intervention is worth further exploring.

Impairment of oculomotor functions in patients with early to advanced amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) can result into an incomplete locked in state (iLIS), in which communication depends on eye tracking computer devices. Oculomotor function impairments in ALS have been reported, but there is little research, particularly with respect to patients in iLIS. In the present study, we compared reflexive and executive oculomotor function by means of an eye tracking test battery between three groups: advanced ALS patients in iLIS (n = 22), patients in early to middle ALS stages (n = 44) and healthy subjects (n = 32). Patients with ALS showed significant deteriorations in oculomotor functions, with stronger impairments in iLIS. More specifically, ALS patients produced visually guided prosaccades with longer latencies and more frequent hypometria compared to healthy subjects. Longest latencies were obtained in iLIS patients, with a stronger prolongation for vertical than for horizontal prosaccades. ALS patients made more antisaccade errors and generated antisaccades with longer latencies. Smooth pursuit was also impaired in ALS. In the earlier ALS stages, bulbar onset patients presented stronger antisaccade and smooth pursuit deficits than spinal onset patients. Our findings reveal a relevant deterioration of important oculomotor functions in ALS, which increases in iLIS. It includes impairments of reflexive eye movements to loss of executive inhibitory control, indicating a progressing pathological involvement of prefrontal, midbrain and brainstem areas. The assessment of oculomotor functions may therefore provide clinically relevant bio- and progression marker, particularly in advanced ALS.

Development and Replication of Objective Measurements of Social Visual Engagement to Aid in Early Diagnosis and Assessment of Autism

Autism spectrum disorder is a common and early-emerging neurodevelopmental condition. While 80% of parents report having had concerns for their child's development before age 2 years, many children are not diagnosed until ages 4 to 5 years or later. To develop an objective performance-based tool to aid in early diagnosis and assessment of autism in children younger than 3 years. In 2 prospective, consecutively enrolled, broad-spectrum, double-blind studies, we developed an objective eye-tracking-based index test for children aged 16 to 30 months, compared its performance with best-practice reference standard diagnosis of autism (discovery study), and then replicated findings in an independent sample (replication study). Discovery and replication studies were conducted in specialty centers for autism diagnosis and treatment. Reference standard diagnoses were made using best-practice standardized protocols by specialists blind to eye-tracking results. Eye-tracking tests were administered by staff blind to clinical results. Children were enrolled from April 27, 2013, until September 26, 2017. Data were analyzed from March 28, 2018, to January 3, 2019. Prespecified primary end points were the sensitivity and specificity of the eye-tracking-based index test compared with the reference standard. Prespecified secondary end points measured convergent validity between eye-tracking-based indices and reference standard assessments of social disability, verbal ability, and nonverbal ability. Data were collected from 1089 children: 719 children (mean [SD] age, 22.4 [3.6] months) in the discovery study, and 370 children (mean [SD] age, 25.4 [6.0] months) in the replication study. In discovery, 224 (31.2%) were female and 495 (68.8%) male; in replication, 120 (32.4%) were female and 250 (67.6%) male. Based on reference standard expert clinical diagnosis, there were 386 participants (53.7%) with nonautism diagnoses and 333 (46.3%) with autism diagnoses in discovery, and 184 participants (49.7%) with nonautism diagnoses and 186 (50.3%) with autism diagnoses in replication. In the discovery study, the area under the receiver operating characteristic curve was 0.90 (95% CI, 0.88-0.92), sensitivity was 81.9% (95% CI, 77.3%-85.7%), and specificity was 89.9% (95% CI, 86.4%-92.5%). In the replication study, the area under the receiver operating characteristic curve was 0.89 (95% CI, 0.86-0.93), sensitivity was 80.6% (95% CI, 74.1%-85.7%), and specificity was 82.3% (95% CI, 76.1%-87.2%). Eye-tracking test results correlated with expert clinical assessments of children's individual levels of ability, explaining 68.6% (95% CI, 58.3%-78.6%), 63.4% (95% CI, 47.9%-79.2%), and 49.0% (95% CI, 33.8%-65.4%) of variance in reference standard assessments of social disability, verbal ability, and nonverbal cognitive ability, respectively. In two diagnostic studies of children younger than 3 years, objective eye-tracking-based measurements of social visual engagement quantified diagnostic status as well as individual levels of social disability, verbal ability, and nonverbal ability in autism. These findings suggest that objective measurements of social visual engagement can be used to aid in autism diagnosis and assessment.

Could an Eye-Tracking Test Aid Clinicians in Making an Autism Diagnosis?

Could an Eye-Tracking Test Aid Clinicians in Making an Autism Diagnosis?

Eye-Tracking–Based Measurement of Social Visual Engagement Compared With Expert Clinical Diagnosis of Autism

In the US, children with signs of autism often experience more than 1 year of delay before diagnosis and often experience longer delays if they are from racially, ethnically, or economically disadvantaged backgrounds. Most diagnoses are also received without use of standardized diagnostic instruments. To aid in early autism diagnosis, eye-tracking measurement of social visual engagement has shown potential as a performance-based biomarker. To evaluate the performance of eye-tracking measurement of social visual engagement (index test) relative to expert clinical diagnosis in young children referred to specialty autism clinics. In this study of 16- to 30-month-old children enrolled at 6 US specialty centers from April 2018 through May 2019, staff blind to clinical diagnoses used automated devices to measure eye-tracking-based social visual engagement. Expert clinical diagnoses were made using best practice standardized protocols by specialists blind to index test results. This study was completed in a 1-day protocol for each participant. Primary outcome measures were test sensitivity and specificity relative to expert clinical diagnosis. Secondary outcome measures were test correlations with expert clinical assessments of social disability, verbal ability, and nonverbal cognitive ability. Eye-tracking measurement of social visual engagement was successful in 475 (95.2%) of the 499 enrolled children (mean [SD] age, 24.1 [4.4] months; 38 [8.0%] were Asian; 37 [7.8%], Black; 352 [74.1%], White; 44 [9.3%], other; and 68 [14.3%], Hispanic). By expert clinical diagnosis, 221 children (46.5%) had autism and 254 (53.5%) did not. In all children, measurement of social visual engagement had sensitivity of 71.0% (95% CI, 64.7% to 76.6%) and specificity of 80.7% (95% CI, 75.4% to 85.1%). In the subgroup of 335 children whose autism diagnosis was certain, sensitivity was 78.0% (95% CI, 70.7% to 83.9%) and specificity was 85.4% (95% CI, 79.5% to 89.8%). Eye-tracking test results correlated with expert clinical assessments of individual levels of social disability (r = -0.75 [95% CI, -0.79 to -0.71]), verbal ability (r = 0.65 [95% CI, 0.59 to 0.70]), and nonverbal cognitive ability (r = 0.65 [95% CI, 0.59 to 0.70]). In 16- to 30-month-old children referred to specialty clinics, eye-tracking-based measurement of social visual engagement was predictive of autism diagnoses by clinical experts. Further evaluation of this test's role in early diagnosis and assessment of autism in routine specialty clinic practice is warranted. ClinicalTrials.gov Identifier: NCT03469986.

A usability evaluation of the perceived user friendliness, accessibility, and inclusiveness of a personalized digital care pathway tool

ObjectiveThis study aimed to acquire insight into the perceived user friendliness, accessibility and inclusiveness of a personalized digital care pathway. Materials & methodsUsability of the tool was tested in an experimental setting. Mixed methods data collection consisted of scenario-based eye tracking tests in a web- or mobile-based prototype of the tool, followed by a questionnaire assessing user friendliness (System Usability Scale; SUS) and a structured interview. Inclusiveness was assessed by subgroup comparisons based on language proficiency, age and education level. Via purposive sampling a heterogeneous population of users (N = 24) was recruited. Eye tracking was used to measure gaze behavior. ResultsOverall, participants were satisfied with the tool (scale 0–10, 7.5; SD = 1.29). User friendliness of the mobile version (68.3; SD = 21.6) was higher than the web version (50.9; SD = 17.3) measured by SUS score (0–100). With regard to accessibility, eye tracking scenarios showed that the menu bar was hard to find (17% mobile, 55% web). In all scenario’s, information was found faster in the mobile version than the web version. Attention was easily drawn to images. Regarding inclusiveness of the tool, we found significantly longer completing time of the scenario tasks for low language proficiency (p-value = 0.029) and higher age subgroups (p-value = 0.049). Lower language proficiency scored a significant lower SUS score (p-value = 0.012). ConclusionsOverall, user friendliness and accessibility were positively evaluated. Assessment of inclusiveness emphasized the need for tailoring digital tools to those with low language proficiency and/or an older age. Co-creation of digital care tools with users is therefore important to match users’ needs, make tools easily understandable and accessible to all users, and ultimately result in better uptake and impact.

Do categorically distinct stressors alter the attention to visual food cues?

Stressor exposure affects food intake as well as the preference for high or low palatability foods, but little is known about how stressor types impact the visual attention to food images. We used eye tracking methodology in humans to determine if activation of the hypothalamus–pituitary-adrenal (HPA) axis and sympathetic nervous system is associated with changes in attention to food images as determined by measuring changes in oculomotor activity. Specifically, we tested two questions: 1) Do categorically distinct stressors alter aspects of visual attention to food images as determined by oculomotor activity (i.e., saccade latency, gaze duration, and saccade bouts)? 2) Do categorically distinct stressors differentially affect visual attention to food images of high or low palatability? A total of sixty participants were randomly divided into one of three test groups: controls, an anticipatory stressor group, or a reactive stressor group. We measured salivary cortisol and salivary alpha-amylase (sAA) before and after stressor exposure to confirm activation of the HPA axis and sympathetic nervous system, respectively. Following stressor exposure participants performed an eye-tracking test using a standardized food picture database (Food-pics). We analyzed saccade latency, gaze duration, and saccade bouts in balanced pairs of food and non-food images. Salivary cortisol was elevated by both stressors, although the elevation in salivary cortisol to the reactive stressor was driven by women only. sAA was elevated only by the anticipatory stressor. There were main effects of image type for all three eye-tracking variables, with initial saccades of shorter latency to food images and longer gaze duration and more saccade bouts with food images. Participants exposed to the reactive stressor reduced gaze duration on food images relative to controls, and this affect was not linked to palatability or salivary cortisol levels. We conclude that the reactive stressor decreased time spent looking at food, but not non-food, images. These data are partly consistent with the idea that reactive stressors reduce attention to non-critical visual signals.

Level of Attention to Motherese Speech as an Early Marker of Autism Spectrum Disorder

Caregivers have long captured the attention of their infants by speaking in motherese, a playful speech style characterized by heightened affect. Reduced attention to motherese in toddlers with autism spectrum disorder (ASD) may be a contributor to downstream language and social challenges and could be diagnostically revealing. To investigate whether attention toward motherese speech can be used as a diagnostic classifier of ASD and is associated with language and social ability. This diagnostic study included toddlers aged 12 to 48 months, spanning ASD and non-ASD diagnostic groups, at a research center. Data were collected from February 2018 to April 2021 and analyzed from April 2021 to March 2022. Gaze-contingent eye-tracking test. Using gaze-contingent eye tracking wherein the location of a toddler's fixation triggered a specific movie file, toddlers participated in 1 or more 1-minute eye-tracking tests designed to quantify attention to motherese speech, including motherese vs traffic (ie, noisy vehicles on a highway) and motherese vs techno (ie, abstract shapes with music). Toddlers were also diagnostically and psychometrically evaluated by psychologists. Levels of fixation within motherese and nonmotherese movies and mean number of saccades per second were calculated. Receiver operating characteristic (ROC) curves were used to evaluate optimal fixation cutoff values and associated sensitivity, specificity, positive predictive value (PPV), and negative predictive value. Within the ASD group, toddlers were stratified based on low, middle, or high levels of interest in motherese speech, and associations with social and language abilities were examined. A total of 653 toddlers were included (mean [SD] age, 26.45 [8.37] months; 480 males [73.51%]). Unlike toddlers without ASD, who almost uniformly attended to motherese speech with a median level of 82.25% and 80.75% across the 2 tests, among toddlers with ASD, there was a wide range, spanning 0% to 100%. Both the traffic and techno paradigms were effective diagnostic classifiers, with large between-group effect sizes (eg, ASD vs typical development: Cohen d, 1.0 in the techno paradigm). Across both paradigms, a cutoff value of 30% or less fixation on motherese resulted in an area under the ROC curve (AUC) of 0.733 (95% CI, 0.693-0.773) and 0.761 (95% CI, 0.717-0.804), respectively; specificity of 98% (95% CI, 95%-99%) and 96% (95% CI, 92%-98%), respectively; and PPV of 94% (95% CI, 86%-98%). Reflective of heterogeneity and expected subtypes in ASD, sensitivity was lower at 18% (95% CI, 14%-22%) and 29% (95% CI, 24%-34%), respectively. Combining metrics increased the AUC to 0.841 (95% CI, 0.805-0.877). Toddlers with ASD who showed the lowest levels of attention to motherese speech had weaker social and language abilities. In this diagnostic study, a subset of toddlers showed low levels of attention toward motherese speech. When a cutoff level of 30% or less fixation on motherese speech was used, toddlers in this range were diagnostically classified as having ASD with high accuracy. Insight into which toddlers show unusually low levels of attention to motherese may be beneficial not only for early ASD diagnosis and prognosis but also as a possible therapeutic target.

Effects of curcumin, phycocyanin, or modified lycopene colorants on the physicochemical and sensory properties of whey protein–cellulose nanocrystal packaging films

To utilize natural hydrophobic/hydrophilic colorants to manufacture good quality and attractive packaging films, we investigated the effects of natural colorants (curcumin, phycocyanin, modified lycopene, and their mixed colorants) on the physicochemical and sensory properties of whey protein isolate–cellulose nanocrystal packaging film. Owing to the improvement in hydrophobicity and spatial density, moisture content (MC) and water vapor permeability (WVP) of films containing curcumin were reduced by 16.91% and 8.49%, respectively, in contrast to that, MC and WVP increased by 10.75% and 4.09%, respectively, in film containing modified lycopene. Mechanical testing, infrared spectra, and X-ray diffraction revealed the retention of structural properties of protein matrix. Rate-All-That-Apply evaluation indicated that films containing colorants enriched tactile and visual sensory characteristics. The eye tracking testing of packed foods showed that preferential attraction depends on the color of the food itself. Thus, a consumer‐oriented multi-colored packaging film with good performance was achieved.

Reliability and Validity of a 9-Point Ocular Alignment Test of Cardinal Gaze using Eye Tracking

The purpose of this study is to determine the reliability of eye-tracking enabled 9-Point Motor Function Test and to determine the validity of the eye-tracking system compared with a traditional Cover Test (CT). Fifty participants between the ages of 19-61 years were tested by a veteran Board-Certified Optometrist using the RightEye 9-Point Motor Function Test (MFT; eye tracking test) and a Cover Test. Participants completed both the 9-Point MFT and the Cover Test in random order and completed the 9-Point MFT test twice to assess test-retest reliability. Reliability was evaluated using Cronbach’s Alpha (CA). Overall reliability was acceptable to excellent per statistical standards. CA were above an acceptable level of .7. Interpupillary distance and pupil diameter were &gt;.9 which is considered excellent. CT and eye tracker displacement were found to be significantly related via Chi Square analysis (P&lt; .001). Logistic regression showed accuracy for left eye as 79.1% and right eye 86.3%. ROC curves were significant (P&lt; .001) for left and right eye displacement. AUC was very high at .879 and .903 respectively. The 9-Point MFT and resulting metrics were deemed to pass reliability and validity statistical standards and as such may provide clinicians with consistent quantifiable information on positions of gaze.