Eye Gaze in Autism Spectrum Disorder: A Review of Neural Evidence for the Eye Avoidance Hypothesis

Seeing beyond words: Visualizing autism spectrum disorder biomarker insights

Objective

This study employs bibliometric and visual analysis to elucidate global research trends in Autism Spectrum Disorder (ASD) biomarkers, identify critical research focal points, and discuss the potential integration of diverse biomarker modalities for precise ASD assessment.

Methods

A comprehensive bibliometric analysis was conducted using data from the Web of Science Core Collection database until December 31, 2022. Visualization tools, including R, VOSviewer, CiteSpace, and gCLUTO, were utilized to examine collaborative networks, co-citation patterns, and keyword associations among countries, institutions, authors, journals, documents, and keywords.

Results

ASD biomarker research emerged in 2004, accumulating a corpus of 4348 documents by December 31, 2022. The United States, with 1574 publications and an H-index of 213, emerged as the most prolific and influential country. The University of California, Davis, contributed significantly with 346 publications and an H-index of 69, making it the leading institution. Concerning journals, the Journal of Autism and Developmental Disorders, Autism Research, and PLOS ONE were the top three publishers of ASD biomarker-related articles among a total of 1140 academic journals. Co-citation and keyword analyses revealed research hotspots in genetics, imaging, oxidative stress, neuroinflammation, gut microbiota, and eye tracking. Emerging topics included "DNA methylation," "eye tracking," "metabolomics," and "resting-state fMRI."

Conclusion

The field of ASD biomarker research is dynamically evolving. Future endeavors should prioritize individual stratification, methodological standardization, the harmonious integration of biomarker modalities, and longitudinal studies to advance the precision of ASD diagnosis and treatment.

Impaired recognition of interactive intentions in adults with autism spectrum disorder not attributable to differences in visual attention or coordination via eye contact and joint attention

Altered nonverbal communication patterns especially with regard to gaze interactions are commonly reported for persons with autism spectrum disorder (ASD). In this study we investigate and differentiate for the first time the interplay of attention allocation, the establishment of shared focus (eye contact and joint attention) and the recognition of intentions in gaze interactions in adults with ASD compared to control persons. Participants interacted via gaze with a virtual character (VC), who they believed was controlled by another person. Participants were instructed to ascertain whether their partner was trying to interact with them. In fact, the VC was fully algorithm-controlled and showed either interactive or non-interactive gaze behavior. Participants with ASD were specifically impaired in ascertaining whether their partner was trying to interact with them or not as compared to participants without ASD whereas neither the allocation of attention nor the ability to establish a shared focus were affected. Thus, perception and production of gaze cues seem preserved while the evaluation of gaze cues appeared to be impaired. An additional exploratory analysis suggests that especially the interpretation of contingencies between the interactants' actions are altered in ASD and should be investigated more closely.

Emotion recognition and social functioning in individuals with autism spectrum condition and intellectual disability

OBJECTIVE

Most previous studies have examined emotion recognition in autism spectrum condition (ASC) without intellectual disability (ID). However, ASC and ID co-occur to a high degree. The main aims of the study were to examine emotion recognition in individuals with ASC and co-occurring intellectual disability (ASC-ID) as compared to individuals with ID alone, and to investigate the relationship between emotion recognition and social functioning.

METHODS

The sample consisted of 30 adult participants with ASC-ID and a comparison group of 29 participants with ID. Emotion recognition was assessed by the facial emotions test, while. social functioning was assessed by the social responsiveness scale-second edition (SRS-2).

RESULTS

The accuracy of emotion recognition was significantly lower in individuals with ASC-ID compared to the control group with ID, especially when it came to identifying angry and fearful emotions. Participants with ASC-ID exhibited more pronounced difficulties in social functioning compared to those with ID, and there was a significant negative correlation between emotion recognition and social functioning. However, emotion recognition accounted for only 8% of the variability observed in social functioning.

CONCLUSION

Our data indicate severe difficulties in the social-perceptual domain and in everyday social functioning in individuals with ASC-ID.

Temporal characteristics of facial ensemble in individuals with autism spectrum disorder: examination from arousal and attentional allocation

Introduction

Individuals with Autism Spectrum Disorder (ASD) show atypical recognition of facial emotions, which has been suggested to stem from arousal and attention allocation. Recent studies have focused on the ability to perceive an average expression from multiple spatially different expressions. This study investigated the effect of autistic traits on temporal ensemble, that is, the perception of the average expression from multiple changing expressions.

Methods

We conducted a simplified temporal-ensemble task and analyzed behavioral responses, pupil size, and viewing times for eyes of a face. Participants with and without diagnosis of ASD viewed serial presentations of facial expressions that randomly switched between emotional and neutral. The temporal ratio of the emotional expressions was manipulated. The participants estimated the intensity of the facial emotions for the overall presentation.

Results

We obtained three major results: (a) many participants with ASD were less susceptible to the ratio of anger expression for temporal ensembles, (b) they produced significantly greater pupil size for angry expressions (within-participants comparison) and smaller pupil size for sad expressions (between-groups comparison), and (c) pupil size and viewing time to eyes were not correlated with the temporal ensemble.

Discussion

These results suggest atypical temporal integration of anger expression and arousal characteristics in individuals with ASD; however, the atypical integration is not fully explained by arousal or attentional allocation.

A Novel Head-Fixed Assay for Social Touch in Mice Uncovers Aversive Responses in Two Autism Models

Social touch, an important aspect of social interaction and communication, is essential to kinship across animal species. How animals experience and respond to social touch has not been thoroughly investigated, in part because of the lack of appropriate assays. Previous studies that examined social touch in freely moving rodents lacked the necessary temporal and spatial control over individual touch interactions. We designed a novel head-fixed assay for social touch in mice, in which the experimenter has complete control to elicit highly stereotyped bouts of social touch between two animals. The user determines the number, duration, context, and type of social touch interactions, while monitoring an array of complex behavioral responses with high resolution cameras. We focused on social touch to the face because of its high translational relevance to humans. We validated this assay in two different models of autism spectrum disorder (ASD), the Fmr1 knock-out (KO) model of Fragile X syndrome (FXS) and maternal immune activation (MIA) mice. We observed higher rates of avoidance running, hyperarousal, and aversive facial expressions (AFEs) to social touch than to object touch, in both ASD models compared with controls. Fmr1 KO mice showed more AFEs to mice of the same sex but whether they were stranger or familiar mice mattered less. Because this new social touch assay for head-fixed mice can be used to record neural activity during repeated bouts of social touch it could be used to uncover underlying circuit differences.SIGNIFICANCE STATEMENT Social touch is important for communication in animals and humans. However, it has not been extensively studied and current assays to measure animals' responses to social touch have limitations. We present a novel head-fixed assay to quantify how mice respond to social facial touch with another mouse. We validated this assay in autism mouse models since autistic individuals exhibit differences in social interaction and touch sensitivity. We find that mouse models of autism exhibit more avoidance, hyperarousal, and aversive facial expressions (AFEs) to social touch compared with controls. Thus, this novel assay can be used to investigate behavioral responses to social touch and the underlying brain mechanisms in rodent models of neurodevelopmental conditions, and to evaluate therapeutic responses in preclinical studies.

Autism symptoms, functional impairments, and gaze fixation measured using an eye-tracker in 6-year-old children

Introduction

Autism spectrum disorder (ASD) is a neurodevelopmental disorder clinically characterized by abnormalities in eye contact during social exchanges. We aimed to clarify whether the amount of gaze fixation, measured at the age of 6 years using Gazefinder, which is an established eye-tracking device, is associated with ASD symptoms and functioning.

Methods

The current study included 742 participants from the Hamamatsu Birth Cohort Study. Autistic symptoms were evaluated according to the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2), and the functioning of the participating children in real life was assessed using the Japanese version of the Vineland Adaptive Behavior Scales, Second Edition (VABS-II). The Gazefinder system was used for gaze fixation rates; two areas of interest (eyes and mouth) were defined in a talking movie clip, and eye gaze positions were calculated through corneal reflection techniques.

Results

The participants had an average age of 6.06 ± 0.14 years (males: 384; 52%). According to ADOS, 617 (83%) children were assessed as having none/mild ASD and 51 (7%) as severe. The average VABS-II scores were approximately 100 (standard deviation = 12). A higher gaze fixation rate on the eyes was associated with a significantly lower likelihood of the child being assigned to the severe ADOS group after controlling for covariates (odds ratio [OR], 0.02; 95% confidence interval [CI], 0.002-0.38). The gaze fixation rate on the mouth was not associated with ASD symptoms. A higher gaze fixation rate on the mouth was associated with a significantly lower likelihood of the child being assigned to the low score group in VABS-II socialization after controlling for covariates (OR, 0.18; 95% CI, 0.04-0.85). The gaze fixation rate on the eyes was not associated with functioning.

Conclusion

We found that children with low gaze fixation rates on the eyes were likely to have more ASD symptoms, and children with low gaze fixation rates on the mouth were likely to demonstrate poorer functioning in socialization. Hence, preschool children could be independently assessed in the general population for clinically relevant endophenotypes predictive of ASD symptoms and functional impairments.

Examination of gaze behaviour in social anxiety disorder using a virtual reality eye-tracking paradigm: protocol for a casecontrol study

INTRODUCTION

Social anxiety disorder (SAD) has an early onset, a high lifetime prevalence, and may be a risk factor for developing other mental disorders. Gaze behaviour is considered an aberrant feature of SAD. Eye-tracking, a novel technology device, enables recording eye movements in real time, making it a direct and objective measure of gaze behaviour. Virtual reality (VR) is a promising tool for assessment and diagnostic purposes. Developing an objective screening tool based on examination of gaze behaviour in SAD may potentially aid early detection. The objective of this current study is, therefore to examine gaze behaviour in SAD utilising VR.

METHODS AND ANALYSIS

A case-control study design is employed in which a clinical sample of 29 individuals with SAD will be compared with a matched healthy control group of 29 individuals. In the VR-based eye-tracking paradigm, participants will be presented to stimuli consisting of high-res 360° 3D stereoscopic videos of three social-evaluative tasks designed to elicit social anxiety. The study will investigate between-group gaze behaviour differences during stimuli presentation.

ETHICS AND DISSEMINATION

The study has been approved by the National Committee on Health Research Ethics for the Capital Region of Denmark (H-22041443). The study has been preregistered on OSF registries: https://doi.org/10.17605/OSF.IO/XCTAKAll participants will be provided with written and oral information. Informed consent is required for all the participants. Participation is voluntarily, and the participants can at any time terminate their participation without any consequences. Study results; positive, negative or inconclusive will be published in relevant scientific journals.

Gaze Following as an Early Diagnostic Marker of Autism in a New Word Learning Task in Toddlers

The aim was to test the use of eye-tracking methodology for the early detection of ASD in a task of association between unfamiliar objects and pseudowords. Significant differences were found between ASD (n = 57) and TD (n = 57) Spanish speaking toddlers in the number and time of fixation. The TD children showed more and longer fixations on eyes and mouth while the ASD children attended almost exclusively to objects, making it difficult to integrate lexical and phonological information. Moreover, the TD toddlers looked at the mouth when the pseudoword was produced while the ASD toddlers did not. Gaze fixation on eyes and mouth during word learning recorded by eye-tracking may be used as a biomarker for the early diagnosis of ASD.

Impairment in reading negative social cues extends beyond the face in autism

Nonverbal expressions are essential to regulating social communication and interaction. Impaired emotion recognition from facial expressions has been linked to various psychiatric conditions characterized by severe social deficits such as autism. As body expressions as an additional source of social-emotional information have attracted little research attention, little is known about whether emotion recognition impairments are specific to faces, or extend to body expressions. This study explored and compared emotion recognition from face versus body expressions in autism spectrum disorder. We compared 30 men with autism spectrum disorder to 30 male age- and IQ-matched control participants in their ability to recognize angry, happy, and neutral expressions from dynamic face and body expressions. Participants with autism spectrum disorder showed impaired recognition of angry expressions from both faces and bodies, while there were no group differences in recognizing happy and neutral expressions. In autism spectrum disorder, recognizing angry face expressions was inversely predicted by gaze avoidance, while recognizing angry body expressions was inversely predicted by impairments in social interaction and autistic traits. These findings suggest that distinct mechanisms may underlie the impaired emotion recognition from face and body expressions in autism spectrum disorder, respectively. Overall, our study demonstrates that emotion-specific recognition difficulties in autism spectrum disorder are not limited to face expressions but extend to emotional body expressions.

Differential Effects of a Behavioral Treatment Probe on Social Gaze Behavior in Fragile X Syndrome and Non-Syndromic Autism Spectrum Disorder

The purpose of this study was to examine potential differences in social learning between individuals with fragile X syndrome (FXS), the leading known inherited cause of intellectual disability, and individuals with non-syndromic autism spectrum disorder (ASD). Thirty school-aged males with FXS and 26 age and symptom-matched males with non-syndromic ASD, were administered a behavioral treatment probe designed to improve levels of social gaze during interactions with others. The treatment probe was administered by a trained behavior therapist over two days in our laboratory and included reinforcement of social gaze in two alternating training conditions - looking while listening and looking while speaking. Prior to each session, children in each group were taught progressive muscle relaxation and breathing techniques to counteract potential increased hyperarousal. Measures included the rate of learning in each group during treatment, in addition to levels of social gaze and heart rate obtained during administration of a standardized social conversation task administered prior to and following the treatment probe. Results showed that learning rates obtained during administration of the treatment probe were significantly less steep and less variable for males with FXS compared to males with non-syndromic ASD. Significant improvements in social gaze were also observed for males with FXS during the social conversation task. There was no effect of the treatment probe on heart rate in either group. These data reveal important differences in social learning between the two groups and have implications for early interventions in the two conditions.

A Scoping Review of Behavioral Interventions for Promoting Social Gaze in Individuals with Autism Spectrum Disorder and Other Developmental Disabilities

Background

Individuals diagnosed with autism spectrum disorder (ASD) commonly experience difficulties maintaining social gaze with others during interactions. Although behavioral interventions targeted to promote social gaze in ASD are evident in the literature, to our knowledge, no review of the literature has been conducted to summarize and evaluate the evidence for these interventions.

Methods

We reviewed and summarized behavioral intervention studies designed to promote social gaze in individuals diagnosed with ASD and other developmental disabilities published in English between 1977 and January 2022 using PsychINFO and PubMed databases.

Results

41 studies met the inclusion criteria describing interventions conducted on 608 individuals. A variety of intervention strategies were employed to promote social gaze in these individuals including discrete trial instruction, prompting, modeling, and imitation. Most studies employed single-case research designs and reported successful outcomes, but limited data were available concerning the generalization, maintenance and social validity of these interventions. An increasing number of studies utilized technology-based procedures including computer application gameplay, gaze-contingent eye tracking devices and humanoid robots.

Conclusions

The present review indicates that behavioral interventions can be successfully employed to promote social gaze in individuals with ASD and other developmental disabilities. However, future research is needed to establish the generalization, maintenance and social validity of these interventions. There are also important ethical issues to be addressed given the increasing divide between treatment advocates and proponents of the neurodiversity movement.

A novel head-fixed assay for social touch in mice uncovers aversive responses in two autism models

Social touch, an important aspect of social interaction and communication, is essential to kinship across animal species. How animals experience and respond to social touch has not been thoroughly investigated, in part due to the lack of appropriate assays. Previous studies that examined social touch in freely moving rodents lacked the necessary temporal and spatial control over individual touch interactions. We designed a novel head-fixed assay for social touch in mice, in which the experimenter has complete control to elicit highly stereotyped bouts of social touch between two animals. The user determines the number, duration, context, and type of social touch interactions, while monitoring with high frame rate cameras an array of complex behavioral responses. We focused on social touch to the face because of their high translational relevance to humans. We validated this assay in two different models of autism spectrum disorder (ASD), the Fmr1 knockout model of Fragile X Syndrome and maternal immune activation mice. We observed increased avoidance, hyperarousal, and more aversive facial expressions to social touch, but not to object touch, in both ASD models compared to controls. Because this new social touch assay for head-fixed mice can be used to record neural activity during repeated bouts of social touch it should be of interest to neuroscientists interested in uncovering the underlying circuits.

Police suspect interviews with autistic adults: The impact of truth telling versus deception on testimony

Investigative interviews by police are socially and cognitively demanding encounters, likely presenting significant challenges to those on the autism spectrum. Behavioral and communication differences mean that autistic people may also be more likely to be perceived as deceptive in the context of an investigative interview. In the present study, 32 autistic and 33 (age and IQ-matched) non-autistic adults took part in a novel virtual burglary scenario in either an 'innocent' or 'guilty' condition. In a subsequent mock-police interview, innocent suspects were instructed to tell the truth about what they did, while guilty suspects were instructed to lie in order to convince the interviewer of their innocence. In the mock-interviews, innocent autistic mock-suspects reported fewer details that would support their innocence than non-autistic mock-suspects, although both innocent and guilty autistic and non-autistic mock-suspects reported similar levels of investigation-relevant information and had similar levels of statement-evidence consistency. In post-interview questionnaires, innocent and guilty autistic mock-suspects self-reported greater difficulty in understanding interview questions, higher anxiety and perceived the interview as less supportive than non-autistic participants. Implications for investigative interviewing with autistic suspects and cues to deception are discussed.

The "Reading the Mind in the Eyes" Test Shows Poor Psychometric Properties in a Large, Demographically Representative U.S. Sample

The Reading the Mind in the Eyes test (RMET) is a widely used measure of theory of mind (ToM). Despite its popularity, there are questions regarding the RMET's psychometric properties. In the current study, we examined the RMET in a representative U.S. sample of 1,181 adults. Key analyses included conducting an exploratory factor analysis on the full sample and examining whether there is a different factor structure in individuals with high versus low scores on the 28-item autism spectrum quotient (AQ-28). We identified overlapping, but distinct, three-factor models for the full sample and the two subgroups. In all cases, each of the three models showed inadequate model fit. We also found other limitations of the RMET, including that nearly a quarter of the RMET items did not meet the criteria for inclusion in the RMET that were established in the original validation study. Due to the RMET's weak psychometric properties and the uncertain validity of individual items, as indicated by our study and previous studies, we conclude that significant caution is warranted when using the RMET as a measure of ToM.

Discrepancy between high non-verbal intelligence and low accuracy at reading emotional expressions in the eyes reflects the magnitude of social-emotional difficulties in autism

Many so-called "high functioning" autistic individuals struggle with daily living skills, and have poorer than expected adult outcomes in employment, relationships, and quality of life. Significant discrepancies between non-verbal intelligence and emotional processing can be observed in autism, but the role of the magnitude of this gap in achieving potential psychosocial outcome is not known. Here, we show in a large group of participants (n = 107), that only among those with an autism diagnosis (n = 33), the gap between non-verbal intelligence (as measured by Raven's matrices) and the ability to perform the Reading the Mind in the Eyes test significantly predicts self-perceived emotional/social difficulties as assessed by the Empathy Quotient. Our results suggest that it is specifically the magnitude of the gap between (high) levels of abstract reasoning skills and poor proficiency in reading emotions expressed by the eyes that predicts self-perceived difficulties in emotional and social interactions among adults with autism. A better understanding of the underlying causes of the discrepancy between potential and actual psychosocial outcomes is the first step toward developing the most appropriate support for this vulnerable population, and our study offers some potentially important insights in this regard.