Eye Movement Indices Research Articles

Individual differences in baseline eye movement indices: Examining the relationships between baseline pupil size, inhibitory control, and fixation stability.

The relationship among baseline pupil size, fixation stability, and inhibitory control were examined in this study. Participants performed a baseline eye measure in which they were instructed to stare at a fixation dot on screen for 2 min. Following the baseline eye measure, participants completed an antisaccade task to measure inhibitory control ability. We found a correlation between baseline pupil size variability and inhibitory control, as well as between fixation stability and inhibitory control. We showed that participants with better inhibitory control exhibited larger variability in pupil size, and those with better fixation stability showed superior inhibitory control ability. Overall, our results indicate that there are significant correlations between inhibitory control and baseline pupil size, as well as between inhibitory control and fixation stability.

Study on the relationship between fixation characteristics and hit rate in psychological procedure training of free throw.

Free throw is an important means of scoring in basketball games. With the improvement of basketball competition level and the enhancement of confrontation degree, the number of free throws in the game gradually increases, so the score of free throw will have an important impact on the result of the game. The purpose of this study is to explore the relationship between visual attention characteristics and hit rate of basketball players in free throw psychological procedure training, so as to provide scientific basis for basketball teaching and training. Forty players with similar free throw abilities were randomly assigned to the experimental group (10 males, 10 females) and control group (10 males, 10 females). The experimental group was free throw psychological procedure training, while the control group was trained with routine training, Eye movement indices (number of fixations, fixation duration, and pupil dilation) and the free throw hit rate and analyzed before and after the experiment. Group differences were examined using t-tests, while paired sample t-tests were conducted to compare pre- and post-test results within each group. The training time and training times of the two groups were the same. There were significant differences in fixation duration, number of fixations, pupil diameter and free throw hit rate between pre-test and post-test in the experimental group (P < 0.05). Post-test, there were significant differences in number of fixations, fixation duration, pupil diameter and free throw hit rate between the two groups (P < 0.05). There was a significant positive correlation between number of fixations and free throw hit rate in top (P < 0.01), and there was a significant positive correlation between fixation duration and hit rate in front (P < 0.01). The psychological procedure training can improve the visual information search strategy and information processing ability of free throw, and significantly improve the free throw hit rate. There was a positive correlation between the front fixation time and the free throw hit rate, and there was a positive correlation between the top number of fixations and the free throw hit rate.

Research and Analysis on the Characteristics of College Students' Emotional Face Processing Based on Computer Vision Technology

The processing of emotional faces by individuals is an important basis for the perception and understanding of emotions. In accordance with the score of Schutte self-report Emotional Intelligence Scale (SSEIS), students in high and low emotional intelligence groups were screened out. Based on the computer vision technology, four kinds of emotional face pictures, including pleasure, anger, sadness and fear, were randomly presented with the help of the eye tracker, and four interest areas were divided into eyebrows, eyes, nose and mouth. The eye-movement indexes of subjects were recorded, and common characteristics of emotional face processing of college students and differences in gender and emotional intelligence were explored. The results showed that college students had a positive bias to emotional face processing and a certain bias to eye area; the number of fixation points in high emotional intelligence group was more and concentrated, and the processing was more rapid and efficient, while the number of fixation points in low emotional intelligence group was less and scattered, and the processing efficiency was lower; female college students were more detailed in emotional face processing.

Applying Kansei Engineering and Eye Movement to Packaging Design Elements—A Case of Tea Packaging Design

ABSTRACTExcellent tea packaging design wins customers and enhances branding. This report studies tea packaging design elements and gives designers constructive references to efficiently improve tea packaging design. The authors of this study first obtained consumers' perception of tea packaging through card sorting and semantic differential (SD). Second, the consumers' Kansei dimensions were extracted by Procrustes analysis (PA). Third, eye tracking technology thoroughly analysed the consumers' eye movement indexes. This technology analysed eye moment as the subjects were exposed to various packaging design elements in order to identify variance, key design elements and outliers.

Diagnosing and tracking depression based on eye movement in response to virtual reality.

Depression is a prevalent mental illness that is primarily diagnosed using psychological and behavioral assessments. However, these assessments lack objective and quantitative indices, making rapid and objective detection challenging. In this study, we propose a novel method for depression detection based on eye movement data captured in response to virtual reality (VR). Eye movement data was collected and used to establish high-performance classification and prediction models. Four machine learning algorithms, namely eXtreme Gradient Boosting (XGBoost), multilayer perceptron (MLP), Support Vector Machine (SVM), and Random Forest, were employed. The models were evaluated using five-fold cross-validation, and performance metrics including accuracy, precision, recall, area under the curve (AUC), and F1-score were assessed. The predicted error for the Patient Health Questionnaire-9 (PHQ-9) score was also determined. The XGBoost model achieved a mean accuracy of 76%, precision of 94%, recall of 73%, and AUC of 82%, with an F1-score of 78%. The MLP model achieved a classification accuracy of 86%, precision of 96%, recall of 91%, and AUC of 86%, with an F1-score of 92%. The predicted error for the PHQ-9 score ranged from -0.6 to 0.6.To investigate the role of computerized cognitive behavioral therapy (CCBT) in treating depression, participants were divided into intervention and control groups. The intervention group received CCBT, while the control group received no treatment. After five CCBT sessions, significant changes were observed in the eye movement indices of fixation and saccade, as well as in the PHQ-9 scores. These two indices played significant roles in the predictive model, indicating their potential as biomarkers for detecting depression symptoms. The results suggest that eye movement indices obtained using a VR eye tracker can serve as useful biomarkers for detecting depression symptoms. Specifically, the fixation and saccade indices showed promise in predicting depression. Furthermore, CCBT demonstrated effectiveness in treating depression, as evidenced by the observed changes in eye movement indices and PHQ-9 scores. In conclusion, this study presents a novel approach for depression detection using eye movement data captured in VR. The findings highlight the potential of eye movement indices as biomarkers and underscore the effectiveness of CCBT in treating depression.

Eye Movement on Predicting Serve Return of College Female Tennis Players of Different Levels in Henan Province

Objective: To quantitatively evaluate the influence of sports level on the behavioral indexes and eye movement indexes of female tennis players by independent sample T test analysis, and to provide strategic basis for visual search of athletes. Methods: In this study, 20 female tennis players from colleges and universities in Henan Province were randomly selected as professional group, and 20 female tennis students from colleges and universities in Henan Province were randomly selected as amateur group. All the tested players had normal vision (5.0 after correction), healthy body, and were right-handed racket holding players. The experiment was conducted to compare the two groups of subjects' prediction accuracy rate, reaction time, total number of effective gaze, gaze track and interest area and other eye movement characteristics when watching videos. Results: The professional group had shorter reaction time, and the correct rate was obviously higher than the amateur group. The total effective fixation point of the professional group was more than that of the amateur group, and the professional group could focus more information. The professional group had a mature grasp of cognitive processing strategies, and their visual search times were targeted; Athletes in the professional group can allocate more attention to the key areas of interest that affect the serve landing point, and highly focus on the interest areas directly related to the direction of the serve, so that they can search information more accurately and improve the accuracy of the prediction.

The effects of object size on spatial orientation: an eye movement study.

The processing of visual information in the human brain is divided into two streams, namely, the dorsal and ventral streams, object identification is related to the ventral stream and motion processing is related to the dorsal stream. Object identification is interconnected with motion processing, object size was found to affect the information processing of motion characteristics in uniform linear motion. However, whether the object size affects the spatial orientation is still unknown. Thirty-eight college students were recruited to participate in an experiment based on the spatial visualization dynamic test. Eyelink 1,000 Plus was used to collect eye movement data. The final direction difference (the difference between the final moving direction of the target and the final direction of the moving target pointing to the destination point), rotation angle (the rotation angle of the knob from the start of the target movement to the moment of key pressing) and eye movement indices under conditions of different object sizes and motion velocities were compared. The final direction difference and rotation angle under the condition of a 2.29°-diameter moving target and a 0.76°-diameter destination point were significantly smaller than those under the other conditions (a 0.76°-diameter moving target and a 0.76°-diameter destination point; a 0.76°-diameter moving target and a 2.29°-diameter destination point). The average pupil size under the condition of a 2.29°-diameter moving target and a 0.76°-diameter destination point was significantly larger than the average pupil size under other conditions (a 0.76°-diameter moving target and a 0.76°-diameter destination point; a 0.76°-diameter moving target and a 2.29°-diameter destination point). A relatively large moving target can resist the landmark attraction effect in spatial orientation, and the influence of object size on spatial orientation may originate from differences in cognitive resource consumption. The present study enriches the interaction theory of the processing of object characteristics and motion characteristics and provides new ideas for the application of eye movement technology in the examination of spatial orientation ability.

Initial Student Attention-Allocation and Flight-Performance Improvements Based on Eye-Movement Data

At the onset of their flight careers, novice pilots often lack clarity regarding the standard attention-allocation pattern. Therefore, to enhance the efficiency of initial flight training, it is crucial for students to develop a comprehensive understanding of flight control and attention-allocation behavior during the learning process. In this study, flight-performance data and eye-movement data from experienced instructors in no-power stall scenarios were collected to create an attention-allocation training course. An experimental group underwent the attention-allocation training course, while a control group followed the traditional teaching curriculum. The disparities between the flight performance and eye-movement indices of the two groups after they completed their respective courses were compared to evaluate the effectiveness of the training. The finding indicate significant differences between the speed losses, altitude losses, and mean course deviations of the instructors and the control group; these indicators had p-values of 0.01, 0.004, and 0.001, respectively. Moreover, significant differences were observed between the altitude losses and mean course deviations of the instructors and the experimental group; these indicators had p-values of 0.006 and 0.001, respectively. The experimental group, which underwent attention-allocation training, exhibited eye-movement indices that closely resembled those of the instructor group, and its instrument scanning was more strategic, thereby resulting in improved flight performance from that of the control group. Additionally, correlations were observed between flight-performance indices and eye-movement indices of the students. Overall, this study demonstrates the effectiveness of an attention-allocation training course designed specifically for a no-power stall scenario. It effectively enhanced the training outcomes of novice pilots, promoted an appropriate allocation of attention to instrument displays, introduced a novel approach to flight training, and ultimately contributed to aviation safety.

An Identity Recognition Model Based on RF-RFE: Utilizing Eye-Movement Data.

Can eyes tell the truth? Can the analysis of human eye-movement data reveal psychological activities and uncover hidden information? Lying is a prevalent phenomenon in human society, but research has shown that people's accuracy in identifying deceptive behavior is not significantly higher than chance-level probability. In this paper, simulated crime experiments were carried out to extract the eye-movement features of 83 participants while viewing crime-related pictures using an eye tracker, and the importance of eye-movement features through interpretable machine learning was analyzed. In the experiment, the participants were independently selected into three groups: innocent group, informed group, and crime group. In the test, the eye tracker was used to extract a total of five categories of eye-movement indexes within the area of interest (AOI), including the fixation time, fixation count, pupil diameter, saccade frequency, and blink frequency, and the differences in these indexes were analyzed. Building upon interpretable learning algorithms, further investigation was conducted to assess the contribution of these metrics. As a result, the RF-RFE suspect identification model was constructed, achieving a maximum accuracy rate of 91.7%. The experimental results further support the feasibility of utilizing eye-movement features to reveal inner psychological activities.

The Role of Spatial Ability and Attention Shifting in Reading of Illustrated Scientific Texts: An Eye Tracking Study

The purpose of the study is to examine the role of spatial ability and attention shifting in reading of illustrated science texts. Thirty-five fourth/fifth elementary students read two science texts. Prior knowledge and retention/transfer learning outcomes were measured using researcher-developed measures. While reading, students’ eye movements were monitored with an eye-tracker. Several eye movement indices were used to reflect reading processes. Fixation count on text/picture was used to represent students’ attentional focus on text or picture. Text to text saccades and picture to picture saccades were used to reflect students’ information organization. Students’ integrative reading behavior was measured by eye movement transitions between text and picture. Wisconsin Card Sorting Test and Visual Perception Skill Test were used to assess attention shifting and visuospatial working memory, respectively. Multiple regressions were conducted to examine whether students’ spatial ability and attention shifting predict text processing, picture processing, or integrative processing of text and picture. Hierarchical regressions were conducted to examine whether students’ integrative reading make unique and direct contributions to their learning outcomes. The study found that 1) both spatial ability and attention shifting are significant predictors for integrative reading behavior while they are not for other processing behaviors (i.e., text processing and picture processing) and 2) integrative reading behaviors in illustrated text reading account for significant amounts of variance in the transfer outcomes while not in the retention outcomes. This study gives practical implications on the development of visual literacy interventions and on how teachers design their instruction about science text reading.

Metacognitive prompts and numerical ordinality in solving word problems: An eye-tracking study.

The ability to translate concrete manipulatives into abstract mathematical formulas can aid in the solving of mathematical word problems among students, and metacognitive prompts play a significant role in enhancing this process. Based on the concept of semantic congruence, we explored the effects of metacognitive prompts and numerical ordinality on information searching and cognitive processing, throughout the process of solving mathematical word problems among primary school students in China. Participants included 73 primary school students (38 boys and 35 girls) with normal or corrected visual acuity. This study was based on a 2 (prompt information: no-prompt, metacognitive-prompt) × 2 (number attribute: cardinal number, ordinal number) mixed experimental design. We analysed multiple eye-movement indices, such as fixation duration, saccadic amplitude, and pupil size, since they pertained to the areas of interest. When solving both types of problems, pupil sizes were significantly smaller under the metacognitive-prompt condition compared with the no-prompt condition, and shorter dwell time for specific sentences, conditional on metacognitive prompts, indicated the optimization of the presented algorithm. Additionally, the levels of fixation durations and saccadic amplitudes were significantly higher when solving ordinal number word problems compared with solving ordinal number problems, indicating that primary school students were less efficient in reading and faced increased levels of difficulty when solving ordinal number problems. The results indicate that for Chinese upper-grade primary school students, cognitive load was lower in the metacognitive prompting condition and when solving cardinal problems, and higher when solving ordinal problems.

Influence of figure information on attention distribution in Chinese landscape painting

Chinese landscape painting is a complex form of visual art. More researchers pay more attention to the creation process and expressed intention of landscape painting. However, the appreciation of works of visual art is often related to cognitive processing, and it is influenced by the content of the works. This study hypothesized that the information of the figure in landscape paintings could guide the allocation of attention and affect cognitive processing. To test this hypothesis, the vertical landscape paintings of the Song and Ming Dynasties were used as experimental materials in the experiment, and the eye-movement technology was applied to record and compare the differences of the eye-movement indexes of landscape paintings with and without figures. The results showed that the dwell time of landscape painting with figure was significantly longer than that of landscape painting without figure, and the dwell time of the interest area of the figure was significantly longer than that of the interest area without figure. However, the first three fixation duration of the interest area with figures is significantly less than that of the interest area without figure, and there was no difference in the saccade counts and the distribution of fixation points between different landscape paintings. It suggested that the figure in the landscape painting can attract peoples’ attention, but it does not have attention priority. Meanwhile, peoples tend to holistic processing when they viewing the vertical landscape paintings, and it is not influenced by the information of figure.

Eye-movement indices of arousal predict ADHD and comorbid externalizing symptoms over a 2-year period

Attention-deficit/hyperactivity disorder (ADHD) follows a variable course across childhood. Disrupted arousal has been hypothesized to underlie core symptoms as well as comorbid internalizing and externalizing conditions. The current study examined eye-movement and pupil-dilation metrics indexing arousal as longitudinal predictors of ADHD, externalizing, and internalizing symptoms over a 2-year period. Participants aged 8–13 years (N = 54, 30% with a diagnosis of ADHD) completed a modified version of the gap-overlap task including arousal-inducing auditory warning signals. Parents rated symptoms at the time of testing and at 2 years follow-up. Phasic alerting (reaction-time reduction after alerting cues) is an index of arousal. Here, larger phasic alerting effects predicted higher ADHD-symptom levels 2 years later. Blunted pupil-dilation responses predicted externalizing symptoms at T2, controlling for ADHD and externalizing at T1. Our results support the theory that ADHD is associated with altered arousal. Blunted arousal reactivity may be a longitudinal risk factor for externalizing problems in children with ADHD symptoms.

The Influence of Spatial Cognitive Model Based on Eye Tracking on Wayfinding Behavior in Underground Parking Lots

Objective In view of the fact that the demand for indoor commercial underground parking lot maps is rising, the effect of underground parking lot map navigation with different spatial cognitive modes on individual wayfinding was studied from the perspective of spatial cognitive modes. Methods Firstly, Unity3D software was used to build the underground parking lot environment, and maps with different types of spatial cognitive modes were used as variables, and single factor analysis was used to record and analyze the number of hesitations of subjects in the process of wayfinding; secondly, eye-movement cognitive data of visual forms were obtained based on eye-tracking experiments; finally, the spatial cognitive modes of users and eye-movement indicators were combined to make recommendations on the design of underground parking lot maps and underground Finally, we suggest the improvement of the underground parking map design and the setting of underground parking related facilities based on the user spatial cognitive patterns and eye-movement indexes. Conclusion The map design affects the navigation effect of users in the process of finding the way in the underground parking lot, and the optimized design method of correlating spatial cognitive patterns and eye-movement tracking indicators is established to provide users with a convenient navigation experience and improve the equipment and facilities related to the underground parking lot for the shopping mall.

Online Assessment of Parafoveal Morphological Processing/Awareness during Reading among Chinese and Korean Adults

ABSTRACT Purpose The present study tested parafoveal morphological processing during sentence reading with two eye-tracking experiments, making use of an implicit measurement of morphological awareness. In Chinese and Korean, each character form typically corresponds to multiple mental lexicons, leading to morphological ambiguity. Method Using the gaze-contingent boundary paradigm, we manipulated the relation between the homographic parafoveal preview morphemes and the target words in Chinese and Korean, respectively, in two experiments. We tested 57 Chinese and 45 Korean university students. Together with baseline conditions in which the previews were either identical or unrelated to the target, we had two critical conditions in which the homographs shared/did not share the same morphemic meaning (i.e., same morpheme/different morpheme) with the target morpheme. Results Across the two experiments, the differences between the same and different morpheme conditions in a number of eye movement indices were significant, consistently showing that appropriate morpho-semantic information facilitates lexical processing. The different-morpheme previews facilitated the target word processing in Chinese but not in Korean reading. Conclusion These findings suggest that morphemic meanings are activated early on during word recognition in Chinese, a logographic orthography, and Korean Hangul, a phonologically transparent writing system, before the word is fixated upon.

Pupillary fluctuation amplitude preceding target presentation is linked to the variable foreperiod effect on reaction time in Psychomotor Vigilance Tasks.

Understanding temporally attention fluctuations can benefit scientific knowledge and real-life applications. Temporal attention studies have typically used the reaction time (RT), which can be measured only after a target presentation, as an index of attention level. We have proposed the Micro-Pupillary Unrest Index (M-PUI) based on pupillary fluctuation amplitude to estimate RT before the target presentation. However, the kind of temporal attention effects that the M-PUI reflects remains unclear. We examined if the M-PUI shows two types of temporal attention effects initially reported for RTs in the variable foreperiod tasks: the variable foreperiod effect (FP effect) and the sequential effect (SE effect). The FP effect refers to a decrease in the RT due to an increase in the foreperiod of the current trial, whereas the SE effect refers to an increase in the RT in the early part of the foreperiod of the current trial due to an increase in the foreperiod of the previous trial. We used a simple reaction task with the medium-term variable foreperiods (Psychomotor Vigilance Task) and found that the M-PUI primarily reflects the FP effect. Inter-individual analyses showed that the FP effect on the M-PUI, unlike other eye movement indices, is correlated with the FP effect on RT. These results suggest that the M-PUI is a potentially powerful tool for investigating temporal attention fluctuations for a partly unpredictable target.

Eye movement indices as predictors of conversion to psychosis in individuals at clinical high risk.

Eye movement abnormalities have been established as an "endophenotype" of schizophrenia. However, less is known about the possibility of these abnormalities as biomarkers for psychosis conversion among clinical high risk (CHR) populations. In the present study, 108 CHR individuals and 70 healthy controls (HC) underwent clinical assessments and eye-tracking tests, comprising fixation stability and free-viewing tasks. According to three-year follow-up outcomes, CHR participants were further stratified into CHR-converter (CHR-C; n = 21) and CHR-nonconverter (CHR-NC; n = 87) subgroups. Prediction models were constructed using Cox regression and logistic regression. TheCHR-C group showed more saccades of the fixation stability test (no distractor) and a reduced saccade amplitude of the free-viewing test than HC. Moreover, the CHR-NC group exhibited excessive saccades and an increased saccade amplitude of the fixation stability test (no distractor; with distractor) compared with HC. Furthermore, two indices could effectively discriminate CHR-C from CHR-NC with an area under the receiver-operating characteristic (ROC) curve of 0.80, including the saccade number of the fixation stabilitytest (no distractor) and thesaccade amplitude of the free-viewing test. Combined with negative symptom scores of the Scale of Prodromal Symptoms, the area was 0.81. These findings support that eye movement alterations might emerge before the onset of clinically overt psychosis and could assist in predicting psychosis transition among CHR populations.

0308 The stability of slow wave sleep and EEG microstructure measures across two consecutive nights of laboratory polysomnography in cognitively normal older adults

Abstract Introduction Healthy and sleep disordered populations show high night-to-night variability of polysomnographic (PSG) macrostructure metrics, however there is evidence of stability in EEG microstructure. In-laboratory PSG is critical to gold standard measures of sleep physiology but multi-night investigations are resource heavy and burdensome to participants. Given the theoretical link between sleep and Alzheimer's disease (AD) pathology (tau and β-amyloid burden), we assessed the night-to-night reliability of sleep macrostructure and EEG microstructure in a group of cognitively normal elderly participating in aging and memory studies. Methods 107 participants (mean = 67±8 yrs., range [54-84 yrs.], 72% female) attended 2 consecutive nights PSG scored according to AASM guidelines for sleep staging, respiratory and leg movement events. Midline EEG (Fz, Cz and Pz referenced to average mastoid signals) were analyzed in 98 participants using an automatic algorithm (DETOKS) for detection of relative slow wave (0.5-4Hz) activity (SWA), NREM2 spindle and K-complexes (KC) densities. Differences between night 1 and 2 for total sleep time (TST), slow wave sleep (SWS), rapid eye movement (REM), stage 2 (%NREM 2), sleep efficiency (SE), apnea hypopnea (AHI) and periodic limb movement (PLM) indices, and EEG microstructure were assessed using t-tests and Wilcoxon rank sum tests where appropriate. Two-way intraclass correlations (ICC) for single unit and absolute agreement were used to determine variability between nights for all measures. Results Night 2 PSGs showed significantly greater TST (6.3 vs 6.8 hours, p&amp;lt;0.001), %REM (17.5 vs 19.7, p&amp;lt;0.001), SE (84.9 vs 87.4%, p&amp;lt;0.02) and SWA (Fz:76.8 vs 78.0%, p&amp;lt;0.01). There were no significant differences between nights for %SWS, %NREM2, AHI, PLMs, spindle and KC densities. ICC and 95% confidence interval estimates were low for TST(0.28), %REM(0.32) and SE(0.32), moderate for %SWS(0.67) and %NREM2(0.59), good for AHI(0.78), SWA(Fz:0.86) and KCs(Fz:0.85), and excellent for PLMs(0.91) and spindles (Pz:0.97). Conclusion SWS, SWA, spindles, KC’s, AHI and PLM indices show good to excellent intra-individual stability across two consecutive nights of PSG. Although there were differences in %REM, SE and SWA, these were numerically small and perhaps functionally or clinically less significant. One night of in-lab PSG is enough to provide reliable estimates of individuals’ SWS, SWA, spindles, KC’s and sleep disorders. Support (If Any) Funding NIH R21AG055002, K24HL109156, R01AG056682, R01AG056531

The impact of COVID-19 pandemic on individuals at clinical high-risk for psychosis: Evidence from eye-tracking measures

Emerging evidence suggested that people with severe mental disorders were more vulnerable to the negative effects of the COVID-19 pandemic. However, few researches investigated the influence of global pandemics on people at clinical high risk (CHR) for psychosis. This study aimed to investigate the impact of the COVID-19 pandemic on clinical symptoms, psychological distress, and eye-tracking characteristics in CHR individuals and healthy participants. Forty-nine CHR individuals and 50 healthy controls (HC) were assessed by PTSD Checklist for DSM-5 (PCL-5), Perceived Stress Scale, 10-item version (PSS-10), and Coronavirus Impact Scale (CIS). Eye movement performances were measured by the tests of fixation stability, free-viewing, and anti-saccade. According to the mean score of CIS, participants were stratified into high-impact (n = 35) and low-impact (n = 64) subgroups. Compared with the HC group, CHR participants reported significantly higher levels of post-traumatic symptoms caused by the COVID-19 pandemic and showed abnormalities in most of the eye movement indexes. Among the altered indexes, the saccade amplitude of fixation stability test (far distractor), the scan path length of free-viewing test, and the accuracy of anti-saccade test were negatively affected by the severity of impact level in the CHR group. Moreover, the altered eye movement indexes were significantly associated with the total scores of CIS, PCL-5, and subscales of the Scale of Prodromal Syndromes (SOPS) among CHR individuals. Overall, our findings suggested the negative impact of the COVID-19 pandemic on the eye movement characteristics of CHR individuals. The present study provides valuable information on physiological distress related to the COVID-19 pandemic and sensitive neuropsychological biomarkers that interacted with social and environment stress in the CHR population.

Effective differentiation between depressed patients and controls using discriminative eye movement features

BackgroundDepression is a common debilitating mental disorder caused by various factors. Identifying and diagnosing depression are challenging because the clinical evaluation of depression is mainly subjective, lacking objective and quantitative indicators. The present study investigated the value and significance of eye movement measurements in distinguishing depressed patients from controls. MethodsNinety-five depressed patients and sixty-nine healthy controls performed three eye movement tests, including fixation stability, free-viewing, and anti-saccade tests, and eleven eye movement indexes were obtained from these tests. The independent t-test was adopted for group comparisons, and multiple logistic regression analysis was employed to identify diagnostic biomarkers. Support vector machine (SVM), quadratic discriminant analysis (QDA), and Bayesian (BYS) algorithms were applied to build the classification models. ResultsDepressed patients exhibited eye movement anomalies, characterized by increased saccade amplitude in the fixation stability test; diminished saccade velocity in the anti-saccade test; and reduced saccade amplitude, shorter scan path length, lower saccade velocity, decreased dynamic range of pupil size, and lower pupil size ratio in the free-viewing test. Four features mentioned above entered the logistic regression equation. The classification accuracies of SVM, QDA, and BYS models reached 86.0%, 81.1%, and 83.5%, respectively. ConclusionsDepressed patients exhibited abnormalities across multiple tests of eye movements, assisting in differentiating depressed patients from healthy controls in a cost-effective and non-invasive manner.