Visual Fixation Patterns during Reciprocal Social Interaction Distinguish a Subgroup of 6-Month-Old Infants At-Risk for Autism from Comparison Infants

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.

Narrative Ability in Autism and First-Degree Relatives

Narrative is an important communication skill for sharing personal experiences and connecting with others. Narrative skills are often impacted in autism spectrum disorder (ASD) and have important consequences for social interactions and relationships. Subtle differences in narrative have also been reported among first-degree relatives of autistic individuals, suggesting that narrative may also be an etiologically important language-related skill that is influenced by genes associated with ASD. This study examined narrative ability and related visual attention during narration in ASD and first-degree relatives of individuals with ASD (siblings and parents) to understand how narrative and related attentional styles may be variably impacted across the spectrum of ASD genetic influence. Participants included 56 autistic individuals, 42 siblings of autistic individuals, 49 controls, 161 parents of autistic individuals, and 61 parent controls. Narratives were elicited using a wordless picture book presented on an eye tracker to record concurrent gaze. Findings revealed parallel patterns of narrative differences among ASD and sibling groups in the use of causal language to connect story elements and the use of cognitive and affective language. More subtle differences within the domain of causal language were evident in ASD parents. Parallel patterns in the ASD and sibling groups were also found for gaze during narration. Findings implicate causal language as a critical narrative skill that is impacted in ASD and may be reflective of ASD genetic influence in relatives. Gaze patterns during narration suggest similar attentional mechanisms associated with narrative among ASD families.

Visual-motor involvement in autism spectrum disorder: could the stereopsis deficit affect motor coordination?

Purpose

Given the known difficulty in sensory processing and in motor skills in patients with Autism Spectrum Disorder (ASD), and since visual impairment could interfere with children’s behaviour, early detection and management of visual-motor difficulties are crucial. This exploratory study aims to evaluate the visual-motor status in a cohort of children affected by ASD.

Methods

The records of patients affected by ASD and admitted between 2018 and 2022 to the Pediatric University Hospital of Verona were reviewed. Best Corrected Visual Acuity, cycloplegic refraction, stereopsis, convergence, complete ocular motility, strabismus examination, slit-lamp anterior segment examination and fundus ophthalmoscopy were collected and reviewed.

Results

A total of 253 patients (203 ASD and 50 healthy controls) were included in the study. A higher number of total orthoptic defects were detected in the ASD group, in comparison with the control group. Specifically, a higher percentage of stereopsis deficit and convergence insufficiency was observed.

Conclusion

In our cohort of children with ASD stereopsis deficit, convergence insufficiency and refractive errors are the most observed ocular conditions. These findings are consistent with the known alterations of motor skills and sensory processing in ASD. Moreover, our study supports the hypothesis that visual acuity is not compromised in children with ASD. As a result, a complete ophthalmic evaluation is highly recommended in children with ASD, to guarantee early detection and treatment of possible visual-motor defects.

Diminished emotion recognition with reduced face gaze in complex situation in individuals with broad autism phenotype

Background/objective

Individuals with broad autism phenotype (BAP) showed a diminished ability to recognize emotion. This study aims to examine whether their decline in emotion recognition ability could be more clearly identified as task complexity increased and whether their decline could be influenced by their eye-gaze patterns.

Method

41 individuals with BAP and 40 healthy controls performed two types of emotion recognition tasks. After confirming conditions wherein the BAP group did not perform well compared to the control group, we compared gaze proportion on faces and context between groups when performing the conditions.

Results

The more difficult the task, the clearer the significant relationships between the level of autistic traits and emotion recognition ability. The BAP group showed lower accuracy compared to the control group when a face with mild emotional intensity was presented with context. In terms of gaze proportion, the BAP group looked less at faces when recognizing emotions compared to the control group.

Conclusion

These findings indicate that diminished emotion recognition ability in individuals with BAP may be influenced by face gaze.

Active Viewing Facilitates Gaze to the Eye Region in Young Children with Autism Spectrum Disorder

Previous studies have shown reduced attention to the eyes in individuals with autism spectrum disorder (ASD). However, most eye-tracking evidence regarding this impairment has been derived from passive viewing tasks. Here, we compared the passive viewing of faces with an active task involving face identification with morphing faces. While typical controls prioritized the eyes over other facial features regardless of viewing condition, autistic children exhibited reduced eye-looking in passive viewing, but displayed increased attention allocation to the eyes when instructed to identify faces. The proportional eye-looking in ASD during facial recognition was negatively related to the autism symptoms severity. These findings provide evidence regarding the specific situations in which diminished eye-looking may rise in young ASD children.

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

Reduced eye contact early in life may play a role in the developmental pathways that culminate in a diagnosis of autism spectrum disorder. However, there are contradictory theories regarding the neural mechanisms involved. According to the amygdala theory of autism, reduced eye contact results from a hypoactive amygdala that fails to flag eyes as salient. However, the eye avoidance hypothesis proposes the opposite-that amygdala hyperactivity causes eye avoidance. This review evaluated studies that measured the relationship between eye gaze and activity in the 'social brain' when viewing facial stimuli. Of the reviewed studies, eight of eleven supported the eye avoidance hypothesis. These results suggest eye avoidance may be used to reduce amygdala-related hyperarousal among people on the autism spectrum.

Early development of social attention in toddlers at high familial risk for autism spectrum disorder

The present study explored the early development of social attention of toddlers at high familial risk (HR) for autism spectrum disorder (ASD). Eighteen HR toddlers and twenty-two toddlers at low familial risk for ASD (LR) between 11 and 24 months were asked to watch paired social and non-social videos. We found that: (1) the initial social preference in HR group decreased with age, but not in LR group; (2) both groups showed significant social habituation across trials, but HR group habituated slightly slower as age increased. These findings suggest that atypical social attention could be an early characteristic of toddlers at high familial risk for ASD.

Application of Eye Tracking Technology in Medicine: A Bibliometric Analysis

Eye tracking provides a quantitative measure of eye movements during different activities. We report the results from a bibliometric analysis to investigate trends in eye tracking research applied to the study of different medical conditions. We conducted a search on the Web of Science Core Collection (WoS) database and analyzed the dataset of 2456 retrieved articles using VOSviewer and the Bibliometrix R package. The most represented area was psychiatry (503, 20.5%) followed by neuroscience (465, 18.9%) and psychology developmental (337, 13.7%). The annual scientific production growth was 11.14% and showed exponential growth with three main peaks in 2011, 2015 and 2017. Extensive collaboration networks were identified between the three countries with the highest scientific production, the USA (35.3%), the UK (9.5%) and Germany (7.3%). Based on term co-occurrence maps and analyses of sources of articles, we identified autism spectrum disorders as the most investigated condition and conducted specific analyses on 638 articles related to this topic which showed an annual scientific production growth of 16.52%. The majority of studies focused on autism used eye tracking to investigate gaze patterns with regards to stimuli related to social interaction. Our analysis highlights the widespread and increasing use of eye tracking in the study of different neurological and psychiatric conditions.

Social endophenotypes in autism spectrum disorder: A scoping review

Endophenotypes are measurable markers of genetic vulnerability to current or future disorder. Autism spectrum disorder (ASD) is well-suited to be examined within an endophenotype framework given past and current emphases on the broader autism phenotype and early detection. We conducted a scoping review to identify potential socially-related endophenotypes of ASD. We focused on paradigms related to sociality (e.g., theory of mind (TOM), social attention), which comprise most of this literature. We integrated findings from traditional behavioral paradigms with brain-based measures (e.g., electroencephalography, functional magnetic resonance imaging). Broadly, infant research regarding social attention and responsivity (Research Domain Criteria (RDoC) domain of affiliation) and attention to faces and voices (social communication) finds consistent abnormality in vulnerable infant siblings. Several additional paradigms that have shown differences in vulnerable infants and young children include animacy perception tasks (perception and understanding of others), measures of recognition and response to familiar faces (attachment), and joint attention and false-belief tasks (understanding mental states). Research areas such as alexithymia (the perception and understanding of self), empathic responding, and vocal prosody may hold interest; however, challenges in measurement across populations and age ranges is a limiting factor. Future work should address sex differences and age dependencies, specificity to ASD, and heterogeneous genetic pathways to disorder within samples individuals with ASD and relatives.

Joint attention and intelligence in children with autism spectrum disorder without severe intellectual disability

In children with autism spectrum disorder (ASD), joint attention is regarded as a predictor of language function, social skills, communication, adaptive function, and intelligence. However, existing information about the association between joint attention and intelligence is limited. Most such studies have examined children with low intelligence. For this study, we investigated whether joint attention is related to intelligence in young children with autism spectrum disorder (ASD) without severe intellectual disability. We analyzed 113 children with ASD aged 40–98 months. Their Kaufman Assessment Battery (K‐ABC) Mental Processing Index (MPI) scores are 60 and more (mean 93.4). We evaluated their intelligence using K‐ABC and evaluated their joint attention using ADOS‐2. After we performed simple regression analyses using K‐ABC MPI and its nine subscales as dependent variables, using joint attention as the independent variable, we identified joint attention as a positive predictor of the MPI and its two subscales. From this result, we conclude that joint attention is related to intelligence in young children with ASD without severe intellectual disability. This result suggests a beneficial effect of early intervention targeting joint attention for children with ASD.

Abnormal visual attention to simple social stimuli in 4-month-old infants at high risk for Autism

Despite an increasing interest in detecting early signs of Autism Spectrum Disorders (ASD), the pathogenesis of the social impairments characterizing ASD is still largely unknown. Atypical visual attention to social stimuli is a potential early marker of the social and communicative deficits of ASD. Some authors hypothesized that such impairments are present from birth, leading to a decline in the subsequent typical functioning of the learning-mechanisms. Others suggested that these early deficits emerge during the transition from subcortically to cortically mediated mechanisms, happening around 2–3 months of age. The present study aimed to provide additional evidence on the origin of the early visual attention disturbance that seems to characterize infants at high risk (HR) for ASD. Four visual preference tasks were used to investigate social attention in 4-month-old HR, compared to low-risk (LR) infants of the same age. Visual attention differences between HR and LR infants emerged only for stimuli depicting a direct eye-gaze, compared to an adverted eye-gaze. Specifically, HR infants showed a significant visual preference for the direct eye-gaze stimulus compared to LR infants, which may indicate a delayed development of the visual preferences normally observed at birth in typically developing infants. No other differences were found between groups. Results are discussed in the light of the hypotheses on the origins of early social visual attention impairments in infants at risk for ASD.

Eye tracking in human interaction: Possibilities and limitations

There is a long history of interest in looking behavior during human interaction. With the advance of (wearable) video-based eye trackers, it has become possible to measure gaze during many different interactions. We outline the different types of eye-tracking setups that currently exist to investigate gaze during interaction. The setups differ mainly with regard to the nature of the eye-tracking signal (head- or world-centered) and the freedom of movement allowed for the participants. These features place constraints on the research questions that can be answered about human interaction. We end with a decision tree to help researchers judge the appropriateness of specific setups.

A Scalable Off-the-Shelf Framework for Measuring Patterns of Attention in Young Children and its Application in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is associated with deficits in the processing of social information and difficulties in social interaction, and individuals with ASD exhibit atypical attention and gaze. Traditionally, gaze studies have relied upon precise and constrained means of monitoring attention using expensive equipment in laboratories. In this work we develop a low-cost off-the-shelf alternative for measuring attention that can be used in natural settings. The head and iris positions of 104 16-31 months children, an age range appropriate for ASD screening and diagnosis, 22 of them diagnosed with ASD, were recorded using the front facing camera in an iPad while they watched on the device screen a movie displaying dynamic stimuli, social stimuli on the left and nonsocial stimuli on the right. The head and iris position were then automatically analyzed via computer vision algorithms to detect the direction of attention. Children in the ASD group paid less attention to the movie, showed less attention to the social as compared to the nonsocial stimuli, and often fixated their attention to one side of the screen. The proposed method provides a low-cost means of monitoring attention to properly designed stimuli, demonstrating that the integration of stimuli design and automatic response analysis results in the opportunity to use off-the-shelf cameras to assess behavioral biomarkers.

Eye Movements and Behavioural Responses to Gaze-Contingent Expressive Faces in Typically Developing Infants and Infant Siblings

Studies with infant siblings of children with Autism Spectrum Disorder have attempted to identify early markers for the disorder and suggest that autistic symptoms emerge between 12 and 24 months of age. Yet, a reliable first-year marker remains elusive. We propose that in order to establish first-year manifestations of this inherently social disorder, we need to develop research methods that are sufficiently socially demanding and realistically interactive. Building on Keemink et al. [2019, Developmental Psychology, 55, 1362-1371], we employed a gaze-contingent eye-tracking paradigm in which infants could interact with face stimuli. Infants could elicit emotional expressions (happiness, sadness, surprise, fear, disgust, anger) from on-screen faces by engaging in eye contact. We collected eye-tracking data and video-recorded behavioural response data from 122 (64 male, 58 female) typically developing infants and 31 infant siblings (17 male, 14 female) aged 6-, 9- and 12-months old. All infants demonstrated a significant Expression by AOI interaction (F(10, 1470) = 10.003, P < 0.001, ŋ_p ²  = 0.064). Infants' eye movements were "expression-specific" with infants distributing their fixations to AOIs differently per expression. Whereas eye movements provide no evidence of deviancies, behavioural response data show significant aberrancies in reciprocity for infant siblings. Infant siblings show reduced social responsiveness at the group level (F(1, 147) = 4.10, P = 0.042, ŋ_p ²  = 0.028) and individual level (Fischer's Exact, P = 0.032). We conclude that the gaze-contingency paradigm provides a realistically interactive experience capable of detecting deviancies in social responsiveness early, and we discuss our results in relation to subsequent infant sibling development. LAY SUMMARY: We investigated how infant siblings of children with autism spectrum disorder respond to interactive faces presented on a computer screen. Our study demonstrates that infant siblings are less responsive when interacting with faces on a computer screen (e.g., they smile and imitate less) in comparison to infants without an older sibling with autism. Reduced responsiveness within social interaction could potentially have implications for how parents and carers interact with these infants. Autism Res 2021, 14: 973-983. © 2020 International Society for Autism Research and Wiley Periodicals LLC.

New approaches to quantify social development in rhesus macaques (Macaca mulatta): Integrating eye tracking with traditional assessments of social behavior

The nonhuman primate provides a sophisticated animal model system both to explore neurobiological mechanisms underlying complex behaviors and to facilitate preclinical research for neurodevelopmental and neuropsychiatric disease. A better understanding of evolutionarily conserved behaviors and brain processes between humans and nonhuman primates will be needed to successfully apply recently released NIMH guidelines (NOT-MH-19-053) for conducting rigorous nonhuman primate neurobehavioral research. Here, we explore the relationship between two measures of social behavior that can be used in both humans and nonhuman primates-traditional observations of social interactions with conspecifics and eye gaze detection in response to social stimuli. Infant male rhesus macaques (Macaca mulatta) serving as controls (N = 14) for an ongoing study were observed in their social rearing groups and participated in a noninvasive, longitudinal eye-tracking study. We found significant positive relationships between time spent viewing eyes of faces in an eye tracker and number of initiations made for social interactions with peers that is consistent with similar observations in human populations. Although future studies are needed to determine if this relationship represents species-typical social developmental processes, these preliminary results provide a novel framework to explore the relationship between social interactions and social attention in nonhuman primate models for neurobehavioral development.

Social orienting and social seeking behaviors in ASD. A meta analytic investigation

Social motivation accounts of autism spectrum disorder (ASD) posit that individuals with ASD find social stimuli less rewarding than neurotypical (NT) individuals. Behaviorally, this is proposed to manifest in reduced social orienting (individuals with ASD direct less attention towards social stimuli) and reduced social seeking (individuals with ASD invest less effort to receive social stimuli). In two meta-analyses, involving data from over 6000 participants, we review the available behavioral studies that assess social orienting and social seeking behaviors in ASD. We found robust evidence for reduced social orienting in ASD, across a range of paradigms, demographic variables and stimulus contexts. The most robust predictor of this effect was interactive content - effects were larger when the stimulus involved an interaction between people. By contrast, the evidence for reduced social seeking indicated weaker evidence for group differences, observed only under specific experimental conditions. The insights gained from this meta-analysis can inform design of relevant task measures for social reward responsivity and promote directions for further study on the ASD phenotype.

Attentional bias to fearful faces in infants at high risk for autism spectrum disorder

Individuals with autism spectrum disorder (ASD) and their first-degree relatives show differences from neurotypical individuals in emotional face processing. Prospective studies of infant siblings of children with ASD, a group at high risk for autism (HRA), allow researchers to examine the early emergence of these differences. This study used eye tracking to examine disengagement of attention from emotional faces (fearful, happy, neutral) at 6, 9, and 12 months in low-risk control infants (LRC) and HRA infants who received a subsequent clinical judgment of ASD (HRA+) or non-ASD (HRA-). Infants saw centrally presented faces followed by a peripheral distractor (with face remaining present). For each emotion, latency to shift to the distractor and percentage of trials with no shift were calculated. Results showed increased saccadic latency and a greater percentage of no-shift trials for fearful faces. No between-group differences were present for emotion; however, there was an interaction between age and group for disengagement latency, with HRA+ infants slower to shift at 12 months compared with the other 2 groups. Exploratory correlational analyses looking at shift biases to fearful faces alongside measures of social behavior at 12 and 18 months (from the Communication and Symbolic Behavior Scales) revealed that for HRA+ infants, 9- and 12-month fear biases were significantly related to 12- and 18-month social abilities, respectively. This work suggests that both low- and high-risk infants show biases to threat-relevant faces, and that for HRA+, differences in attention shifting emerge with age, and a stronger fear bias could potentially relate to less social difficulty. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Infants at Risk for Autism Spectrum Disorder: Frequency, Quality, and Variety of Joint Attention Behaviors

Initiation of joint attention is a critical developmental function related to further social communicative development in infancy. Joint attention appears to be impaired very early in life for children with autism spectrum disorder (ASD), well before a formal diagnosis is established. To observe the early development of joint attention, we prospectively followed infant siblings at high risk for ASD (HR) and low-risk (LR) infants. Initiations of joint attention behaviors were coded with respect to frequency, quality, and variety from videos taken during the administration of the Autism Observation Schedule for Infants. Participants were further stratified based on the presence of ASD (n = 17) or language delay (n = 19) at 3 years of age. Our results revealed that initiations of joint attention are impaired from 12 months of age in both children with ASD and those with language delay, especially for use of gestures (i.e., showing and pointing). At 18 months, fewer initiations of joint attention in all three dimensions distinguished infants with ASD, compared to infants with language delay and HR and LR infants without a diagnosis. Beyond the definition of initiation of joint attention as an early sign for ASD, clinical implications of these results concern the importance of intervening on frequency, quality, and variety of joint attention as early as possible in infants at heightened risk for ASD.

Callous-unemotional traits in youth with autism spectrum disorder (ASD): replication of prevalence estimates and associations with gaze patterns when viewing fearful faces

Research suggests an increased prevalence of callous-unemotional (CU) traits in children with autism spectrum disorder (ASD), and a similar impairment in fear recognition to that reported in non-ASD populations. However, past work has used measures not specifically designed to measure CU traits and has not examined whether decreased attention to the eyes reported in non-ASD populations is also present in individuals with ASD. The current paper uses a measure specifically designed to measure CU traits to estimate prevalence in a large community-based ASD sample. Parents of 189 adolescents with ASD completed questionnaires assessing CU traits, and emotional and behavioral problems. A subset of participants completed a novel emotion recognition task (n = 46). Accuracy, reaction time, total looking time, and number of fixations to the eyes and mouth were measured. Twenty-two percent of youth with ASD scored above a cut-off expected to identify the top 6% of CU scores. CU traits were associated with longer reaction times to identify fear and fewer fixations to the eyes relative to the mouth during the viewing of fearful faces. No associations were found with accuracy or total looking time. Results suggest the mechanisms that underpin CU traits may be similar between ASD and non-ASD populations.

Mapping the Specific Pathways to Early-Onset Mental Health Disorders: The "Watch Me Grow for REAL" Study Protocol

BACKGROUND

From birth, the human propensity to selectively attend and respond to critical super-stimuli forms the basis of future socio-emotional development and health. In particular, the first super-stimuli to preferentially engage and elicit responses in the healthy newborn are the physical touch, voice and face/eyes of caregivers. From this grows selective attention and responsiveness to emotional expression, scaffolding the development of empathy, social cognition, and other higher human capacities. In this paper, the protocol for a longitudinal, prospective birth-cohort study is presented. The major aim of this study is to map the emergence of individual differences and disturbances in the system of social-Responsiveness, Emotional Attention, and Learning (REAL) through the first 3 years of life to predict the specific emergence of the major childhood mental health problems, as well as social adjustment and impairment more generally. A further aim of this study is to examine how the REAL variables interact with the quality of environment/caregiver interactions.

METHODS/DESIGN

A prospective, longitudinal birth-cohort study will be conducted. Data will be collected from four assessments and mothers' electronic medical records.

DISCUSSION

This study will be the first to test a clear developmental map of both the unique and specific causes of childhood psychopathology and will identify more precise early intervention targets for children with complex comorbid conditions.

Social attention: What is it, how can we measure it, and what can it tell us about autism and ADHD?

Neurodevelopmental disorders like autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) affect 2-10% of children worldwide but are still poorly understood. Prospective studies of infants with an elevated familial likelihood of ASD or ADHD can provide insight into early mechanisms that canalize development down a typical or atypical course. Such work holds potential for earlier identification and intervention to support optimal outcomes in individuals with neurodevelopmental disorders. Disrupted attention may be involved in developmental trajectories to ASD and ADHD. Specifically, altered attention to social stimuli has been suggested as a possible endophenotype of ASD, lying between genetic factors impacting brain development and later symptoms. Similarly, changes in domain-general aspects of attention are commonly seen in ADHD and emerging evidence suggests these may begin in infancy. Could these patterns point to a common risk factor for both disorders? Or does social attention reflect the activity of a particular network of brain systems that is distinct to those underpinning general attention skills? One challenge to addressing such questions is our lack of understanding of the relation between social and general attention. In this chapter we review evidence from infants with later ASD and ADHD that illuminates this question.

Application of the Still-Face Paradigm in Early Screening for High-Risk Autism Spectrum Disorder in Infants and Toddlers

Background: Although autism spectrum disorder (ASD) can currently be diagnosed at the age of 2 years, age at ASD diagnosis is still 40 months or even later. In order to early screening for ASD with more objective method, behavioral videos were used in a number of studies in recent years. Method: The still-face paradigm (SFP) was adopted to measure the frequency and duration of non-social smiling, protest behavior, eye contact, social smiling, and active social engagement in high-risk ASD group (HR) and typical development group (TD) (HR: n = 45; TD: n = 43). The HR group was follow-up until they were 2 years old to confirm final diagnosis. Machine learning methods were used to establish models for early screening of ASD. Results: During the face-to-face interaction (FF) episode of the SFP, there were statistically significant differences in the duration and frequency of eye contact, social smiling, and active social engagement between the two groups. During the still-face (SF) episode, there were statistically significant differences in the duration and frequency of eye contact and active social engagement between the two groups. The 45 children in the HR group were reclassified into two groups after follow-up: five children in the N-ASD group who were not meet the criterion of ASD and 40 children in the ASD group. The results showed that the accuracy of Support Vector Machine (SVM) classification was 83.35% for the SF episode. Conclusion: The use of the social behavior indicator of the SFP for a child with HR before 2 years old can effectively predict the clinical diagnosis of the child at the age of 2 years. The screening model constructed using SVM based on the SF episode of the SFP was the best. This also proves that the SFP has certain value in high-risk autism spectrum disorder screening. In addition, because of its convenient, it can provide a self-screening mode for use at home. Trial registration: Chinese Clinical Trial Registry, ChiCTR-OPC-17011995.

Machine Learning to Study Social Interaction Difficulties in ASD

Autism Spectrum Disorder (ASD) is a spectrum of neurodevelopmental conditions characterized by difficulties in social communication and social interaction as well as repetitive behaviors and restricted interests. Prevalence rates have been rising, and existing diagnostic methods are both extremely time and labor consuming. There is an urgent need for more economic and objective automatized diagnostic tools that are independent of language and experience of the diagnostician and that can help deal with the complexity of the autistic phenotype. Technological advancements in machine learning are offering a potential solution, and several studies have employed computational approaches to classify ASD based on phenomenological, behavioral or neuroimaging data. Despite of being at the core of ASD diagnosis and having the potential to be used as a behavioral marker for machine learning algorithms, only recently have movement parameters been used as features in machine learning classification approaches. In a proof-of-principle analysis of data from a social interaction study we trained a classification algorithm on intrapersonal synchrony as an automatically and objectively measured phenotypic feature from 29 autistic and 29 typically developed individuals to differentiate those individuals with ASD from those without ASD. Parameters included nonverbal motion energy values from 116 videos of social interactions. As opposed to previous studies to date, our classification approach has been applied to non-verbal behavior objectively captured during naturalistic and complex interactions with a real human interaction partner assuring high external validity. A machine learning approach lends itself particularly for capturing heterogeneous and complex behavior in real social interactions and will be essential in developing automatized and objective classification methods in ASD.

The robustness of eye-mouth index as an eye-tracking metric of social attention in toddlers

Eye-tracking research on social attention in infants and toddlers has included heterogeneous stimuli and analysis techniques. This allows measurement of looking to inner facial features under diverse conditions but restricts across-study comparisons. Eye-mouth index (EMI) is a measure of relative preference for looking to the eyes or mouth, independent of time spent attending to the face. The current study assessed whether EMI was more robust to differences in stimulus type than percent dwell time (PDT) toward the eyes, mouth, and face. Participants were typically developing toddlers aged 18 to 30 months (N = 58). Stimuli were dynamic videos with single and multiple actors. It was hypothesized that stimulus type would affect PDT to the face, eyes, and mouth, but not EMI. Generalized estimating equations demonstrated that all measures including EMI were influenced by stimulus type. Nevertheless, planned contrasts suggested that EMI was more robust than PDT when comparing heterogeneous stimuli. EMI may allow for a more robust comparison of social attention to inner facial features across eye-tracking studies.

Visual scanning preferences in low birth weight preterm infants

INTRODUCTION

Few studies have used eye tracking as a screening tool for autism spectrum disorder (ASD) in preterm infants.

OBJECTIVES

To evaluate fixation time on social and non-social figures and percentage of preterm babies who gazed at the images.

METHODS

This was a cross-sectional study of 31 preterm infants born weighing ≤ 2,000 g in which eye gaze was evaluated at 6 months of corrected age. Six boards with social and non-social figures were projected on a computer screen, successively, evaluating time and percentage of preterm babies who gazed at each board. The Modified Checklist for Autism in Toddlers (M-CHAT) was answered at 18 months of corrected age.

RESULTS

Preterm infants showed longer visual fixation time on social figures compared with non-social images, regardless of the position of the social figure on the board. Similar percentages of preterm infants gazed either at social or non-social figures, at social figures with a direct or an indirect look, and at the eyes or mouth of the social figures. No preterm infant screened positive on the M-CHAT.

CONCLUSION

At 6 months of corrected age, preterm infants show the ability to gaze in an eye-tracking test, with preference for social figures, suggesting that this tool could be useful as another screening instrument for ASD.

Deviations from Typical Developmental Trajectories Detectable at 9 Months of Age in Low Risk Children Later Diagnosed with Autism Spectrum Disorder

This study was designed to track the developmental trajectory, during the first 24 months of life, of 335 low-risk infants later diagnosed with Autism Spectrum Disorder and identify early deviations observed in routine Well Care checkups. We compared their achievements to typically developing children and to children later diagnosed with non-autistic developmental impairments. The results show that in the first 6 months, the children with autism showed normal acquisition of milestones, whereas by 9 months of age they began to fail the language/communication, as well as motor items when compared to typical and delayed non-autistic children. Regular check-up visits may be useful in detecting early failure in achieving milestones, leading to earlier referral for further evaluation and treatment.

The role of shape recognition in figure/ground perception in infancy

In this study we sought to determine whether infants, like adults, utilize previous experience to guide figure/ground processing. After familiarization to a shape, 5-month-olds preferentially attended to the side of an ambiguous figure/ground test stimulus corresponding to that shape, suggesting that they were viewing that portion as the figure. Infants' failure to exhibit this preference in a control condition in which both sides of the test stimulus were displayed as figures indicated that the results in the experimental condition were not due to a preference between two figure shapes. These findings demonstrate for the first time that figure/ground processing in infancy is sensitive to top-down influence. Thus, a critical aspect of figure/ground processing is functional early in life.

Sex Differences in Social Attention in Infants at Risk for Autism

We studied visual attention to emotional faces in 10-month-old infant siblings of children with ASD (ASD-sibs; N = 70) and a siblings of typically developing children (N = 29) using static stimuli. Contrary to our predictions, we found no evidence for atypical gaze behavior in ASD-sibs when boys and girls were analyzed together. However, a sex difference was found in ASD-sibs' visual attention to the mouth. Male ASD-sibs looked more at the mouth across emotions compared to male controls and female ASD-sibs. In contrast, female ASD-sibs looked less at the mouth compared to female controls. These findings suggest that some aspects of early emerging atypical social attention in ASD-sibs may be sex specific.

Understanding facial expressivity in autism spectrum disorder: An inside out review of the biological basis and clinical implications

Deficits in decoding and understanding facially expressed emotions occur commonly in persons with autism spectrum disorder (ASD), which contribute to the impairment of social communication that serves as one of its core diagnostic criteria. Research suggests that abnormalities of visual scanning of the face, activation of key nodes within the "social brain" by facially expressed emotions, functional connectivity within and between nodes of the "social brain", and transduction of specific neurotransmitter/neuromodulatory signals contribute to the pathogenesis of these deficits in at least some persons with ASD. Importantly, the etiologies of these deficits are heterogeneous and include genetic, immunologic, and inflammatory mechanisms, as well as in utero exposures to drugs and toxins. The manifestation and severity of these deficits can also be influenced by developmental age, IQ and genetic background. Consistent with the goals of the Special Issue, the current Review is intended to familiarize the readership with several of the leading neurobiological mechanisms proposed to underlie these deficits in decoding facially expressed emotions and stimulate interest in translational preclinical and clinical investigations, whose ultimate purpose is to attenuate their severity and, thereby, improve functional outcomes of persons with ASD.

Naturally Occurring Nonhuman Primate Models of Psychosocial Processes

Human research into psychological processes such as anxiety, depression, or loneliness typically involves accruing cases in which the phenomenon of interest is naturally occurring, and then comparing such a sample with control cases. In contrast, animal research designed to model similar processes to test mechanistic hypotheses typically involves inducing the phenomenon of interest via some exogenously (i.e., human) administered procedure. In the present review, the author proposes that naturally occurring animal models can complement induced models in understanding complex psychological phenomena. Advantages and disadvantages of naturally occurring versus induced models are described, and detailed examples of three naturally occurring models-for loneliness and health, behavioral inhibition and asthma, and social functioning and autism-are described, along with a formal program (the BioBehavioral Assessment program) at the California National Primate Research Center, that is designed to quantify variation in biobehavioral processes in infant rhesus macaques to facilitate development of naturally occurring models. It is argued that, because of the similarity in complex behavioral and psychological processes between macaques and humans, naturally occurring primate models provide a bridge between human studies and induced primate models and have the potential to identify new models for translational research.

A break in parental interaction does not affect the temporal dependency of infant social engagement, but disrupts non-social engagement

Infant looking patterns during interaction offer an early window into social and nonsocial engagement. Recent evidence indicates that infant looks exhibit temporal dependency-one look duration predicts the next look duration. It is unknown, however, whether temporal dependency emerges as infants structure their own looking or whether it is influenced by interaction. We examined whether a perturbation of social interaction affected temporal dependency. Using the Face-to-Face/Still-Face procedure, we compared temporal dependency during parental interaction (the Face-to-Face & Reunion episodes) to parental non-responsiveness (the Still-Face episode). Overall, the durations of successive infant looks were predictable; past behavior constrained current behavior. The duration of one look at the parent (Face Look) predicted the duration of the next Face Look. Likewise, the duration of a look at any place that was not the parent's face (Away Look) predicted the duration of the next Away Look. The temporal dependency of Face Looks (social engagement) was unaffected by the Still-Face perturbation, but the temporal dependency of Away Looks (nonsocial engagement) declined during the Still-Face. Infant temporal structuring of engagement during social looking is not dependent on parental interaction while the disruption of interaction affects infants' structuring of their own non-social engagement.

Is the eye-movement field confused about fixations and saccades? A survey among 124 researchers

Eye movements have been extensively studied in a wide range of research fields. While new methods such as mobile eye tracking and eye tracking in virtual/augmented realities are emerging quickly, the eye-movement terminology has scarcely been revised. We assert that this may cause confusion about two of the main concepts: fixations and saccades. In this study, we assessed the definitions of fixations and saccades held in the eye-movement field, by surveying 124 eye-movement researchers. These eye-movement researchers held a variety of definitions of fixations and saccades, of which the breadth seems even wider than what is reported in the literature. Moreover, these definitions did not seem to be related to researcher background or experience. We urge researchers to make their definitions more explicit by specifying all the relevant components of the eye movement under investigation: (i) the oculomotor component: e.g. whether the eye moves slow or fast; (ii) the functional component: what purposes does the eye movement (or lack thereof) serve; (iii) the coordinate system used: relative to what does the eye move; (iv) the computational definition: how is the event represented in the eye-tracker signal. This should enable eye-movement researchers from different fields to have a discussion without misunderstandings.

The redeployment of attention to the mouth of a talking face during the second year of life

Previous studies have found that when monolingual infants are exposed to a talking face speaking in a native language, 8- and 10-month-olds attend more to the talker's mouth, whereas 12-month-olds no longer do so. It has been hypothesized that the attentional focus on the talker's mouth at 8 and 10 months of age reflects reliance on the highly salient audiovisual (AV) speech cues for the acquisition of basic speech forms and that the subsequent decline of attention to the mouth by 12 months of age reflects the emergence of basic native speech expertise. Here, we investigated whether infants may redeploy their attention to the mouth once they fully enter the word-learning phase. To test this possibility, we recorded eye gaze in monolingual English-learning 14- and 18-month-olds while they saw and heard a talker producing an English or Spanish utterance in either an infant-directed (ID) or adult-directed (AD) manner. Results indicated that the 14-month-olds attended more to the talker's mouth than to the eyes when exposed to the ID utterance and that the 18-month-olds attended more to the talker's mouth when exposed to the ID and the AD utterance. These results show that infants redeploy their attention to a talker's mouth when they enter the word acquisition phase and suggest that infants rely on the greater perceptual salience of redundant AV speech cues to acquire their lexicon.

Initiation of joint attention and related visual attention processes in infants with autism spectrum disorder: Literature review

Autism spectrum disorder (ASD) represents a group of neurodevelopmental disabilities that can be difficult to identify before the age of 2 or 3 years, the age when the full range of behavioral symptoms has emerged in most cases. Initiation of joint attention is an important developmental function in which impairments are already observable before the second birthday and can predict children's ASD symptomatology. In the first part of this review, we summarize results pertaining to retrospective studies of initiation of joint attention in children with ASD and prospective studies of infants at high risk for ASD during the first 2 years, when this behavior is becoming more complex in terms of frequency, quality, and variety. We will also discuss the implications of impairments in dyadic engagement, a precursor of joint attention behavior, for the early development of joint attention. Finally, the early development of initiation of joint attention has been related to specific visual attention mechanisms such as social orienting and visual disengagement. In the second part of this review, we provide an overview of the relationship between those visual attention mechanisms and subsequent social-communication impairments. Clinical and research implications of these findings for both early detection and early intervention will be discussed.

Diminished socially selective neural processing in 5-month-old infants at high familial risk of autism

The social and communicative difficulties that characterize autism spectrum disorder (ASD) are considered the most striking feature of the disorder. Research has reported that individuals with ASD show abnormalities in the brain regions associated with the processing of social information. Importantly, a recent study using functional near-infrared spectroscopy (fNIRS) found the first evidence of atypicalities in the neural processing of social information in 4- to 6-month-old infants at high familial risk of ASD. These findings provide an important step in the search for early markers of ASD and highlight the potential for neuroimaging techniques to detect atypical patterns of neural activity prior to the manifestation of most behavioural symptoms. This study aimed to extend the findings of reduced neural sensitivity to social stimuli in an independent cohort. Twenty-nine 5-month-old infants (13 low-risk infants, 16 high-risk infants) were presented with social and non-social visual stimuli, similar to the previous experiment. Importantly, a non-social dynamic motion control condition was introduced allowing the comparison between social dynamic and non-social, static, as well as dynamic stimuli. We found that while low-risk infants showed activation to social stimuli in the right posterior temporal cortex, this activation was reduced in infants at high risk of ASD. Although the current sample size was relatively small, our results replicate and extend previous work and provide evidence for a social processing difference in infants at risk of autism. Future research will determine whether these differences relate to an eventual ASD diagnosis or may rather reflect the broader autism phenotype.

Eye Tracking as a Marker of Hyperphagia in Prader-Willi Syndrome

This study examined the feasibility of eye tracking measures as markers of hyperphagia in 42 children and adults with Prader-Willi syndrome (PWS). Gaze data collected during free visual exploration of complex displays revealed that food images may not have an overall superior salience in PWS. However, increased attention to food in the context of other high-interest items was associated with higher scores on caregiver reports of hyperphagia. The study also provided preliminary evidence of test-retest reliability of eye tracking measures, suggesting that gaze characteristics may be a promising objective marker of food-related interests in PWS.

The effect of visual cues on performance in the ultimatum game in individuals with autism spectrum disorder

The Ultimatum Game (UG) allows for the assessment of altruistic behavior as well as the perception of fairness. We examined the effects of visual social cues (gaze of others), factors associated with autism, and trust on UG performance in typical adults (TAs) and individuals with autism spectrum disorder (ASD). We hypothesized that individuals with ASD would be less affected by visual social cues than TAs. We recruited 30 TAs and 30 individuals with ASD. Participants completed 30 trials of the UG, during which the visual background was altered to include either stylized eyespots, flowers, or a neutral background. Reaction times and money distributed in each condition were recorded. Reaction times did not vary among background conditions in either group, although individuals with ASD responded more slowly overall. TAs distributed less money in the neutral background and flowers conditions than in the eyespots condition, while no significant differences in the amount of money distributed were observed among background conditions for individuals with ASD, who also distributed more money overall than TAs. Such findings may be due to decreased susceptibility to social cues among individuals with ASD.

Responding to Other People's Direct Gaze: Alterations in Gaze Behavior in Infants at Risk for Autism Occur on Very Short Timescales

Atypical gaze processing has been reported in children with autism spectrum disorders (ASD). Here we explored how infants at risk for ASD respond behaviorally to others' direct gaze. We assessed 10-month-olds with a sibling with ASD (high risk group; n = 61) and a control group (n = 18) during interaction with an adult. Eye-tracking revealed less looking at the adult in the high risk group during 300-1000 ms after the adult initiated direct gaze: a short alteration that is likely to go unnoticed by the naked eye. Data aggregated over longer segments (the traditional eye-tracking approach) showed no group differences. Although findings are limited by lack of outcome data, they are in line with theories linking atypical eye processing to the emergence of ASD.

Attempting to "Increase Intake from the Input": Attention and Word Learning in Children with Autism

Previous work has demonstrated that social attention is related to early language abilities. We explored whether we can facilitate word learning among children with autism by directing attention to areas of the scene that have been demonstrated as relevant for successful word learning. We tracked eye movements to faces and objects while children watched videos of a woman teaching them new words. Test trials measured participants' recognition of these novel word-object pairings. Results indicate that for children with autism and typically developing children, pointing to the speaker's mouth while labeling a novel object impaired performance, likely because it distracted participants from the target object. In contrast, for children with autism, holding the object close to the speaker's mouth improved performance.

The organization and reorganization of audiovisual speech perception in the first year of life

The period between six and 12 months is a sensitive period for language learning during which infants undergo auditory perceptual attunement, and recent results indicate that this sensitive period may exist across sensory modalities. We tested infants at three stages of perceptual attunement (six, nine, and 11 months) to determine 1) whether they were sensitive to the congruence between heard and seen speech stimuli in an unfamiliar language, and 2) whether familiarization with congruent audiovisual speech could boost subsequent non-native auditory discrimination. Infants at six- and nine-, but not 11-months, detected audiovisual congruence of non-native syllables. Familiarization to incongruent, but not congruent, audiovisual speech changed auditory discrimination at test for six-month-olds but not nine- or 11-month-olds. These results advance the proposal that speech perception is audiovisual from early in ontogeny, and that the sensitive period for audiovisual speech perception may last somewhat longer than that for auditory perception alone.

Sensing Technologies for Autism Spectrum Disorder Screening and Intervention

This paper reviews the state-of-the-art in sensing technologies that are relevant for Autism Spectrum Disorder (ASD) screening and therapy. This disorder is characterized by difficulties in social communication, social interactions, and repetitive behaviors. It is diagnosed during the first three years of life. Early and intensive interventions have been shown to improve the developmental trajectory of the affected children. The earlier the diagnosis, the sooner the intervention therapy can begin, thus, making early diagnosis an important research goal. Technological innovations have tremendous potential to assist with early diagnosis and improve intervention programs. The need for careful and methodological evaluation of such emerging technologies becomes important in order to assist not only the therapists and clinicians in their selection of suitable tools, but to also guide the developers of the technologies in improving hardware and software. In this paper, we survey the literatures on sensing technologies for ASD and we categorize them into eye trackers, movement trackers, electrodermal activity monitors, tactile sensors, vocal prosody and speech detectors, and sleep quality assessment devices. We assess their effectiveness and study their limitations. We also examine the challenges faced by this growing field that need to be addressed before these technologies can perform up to their theoretical potential.

Differential Attention to Faces in Infant Siblings of Children with Autism Spectrum Disorder and Associations with Later Social and Language Ability

A growing body of literature has begun to explore social attention in infant siblings of children with autism spectrum disorder (ASD) with hopes of identifying early differences that are associated with later ASD or other aspects of development. The present study used eye-tracking to familiar (mother) and unfamiliar (stranger) faces in two groups of 6-month-old infants: infants with no family history of ASD (low-risk controls; LRC), and infants at high risk for ASD (HRA), by virtue of having an older sibling with ASD. HRA infants were further characterized based on autism classification at 24 months or older as HRA- (HRA without an ASD outcome) or HRA+ (HRA with an ASD outcome). For time scanning faces overall, HRA+ and LRC showed similar patterns of attention, and this was significantly greater than in HRA-. When examining duration of time spent on eyes and mouth, all infants spent more time on eyes than mouth, but HRA+ showed the greatest amount of time looking at these regions, followed by LRC, then HRA-. LRC showed a positive association between 6-month attention to eyes and 18-month social-communicative behavior, while HRA- showed a negative association between attention to eyes at 6 months and expressive language at 18 months (all correlations controlled for non-verbal IQ; HRA- correlations held with and without the inclusion of the small sample of HRA+). Differences found in face scanning at 6 months, as well as associations with social communication at 18 months, point to potential variation in the developmental significance of early social attention in children at low and high risk for ASD.

Early Predictors of Impaired Social Functioning in Male Rhesus Macaques (Macaca mulatta)

Autism spectrum disorder (ASD) is characterized by social cognition impairments but its basic disease mechanisms remain poorly understood. Progress has been impeded by the absence of animal models that manifest behavioral phenotypes relevant to ASD. Rhesus monkeys are an ideal model organism to address this barrier to progress. Like humans, rhesus monkeys are highly social, possess complex social cognition abilities, and exhibit pronounced individual differences in social functioning. Moreover, we have previously shown that Low-Social (LS) vs. High-Social (HS) adult male monkeys exhibit lower social motivation and poorer social skills. It is not known, however, when these social deficits first emerge. The goals of this study were to test whether juvenile LS and HS monkeys differed as infants in their ability to process social information, and whether infant social abilities predicted later social classification (i.e., LS vs. HS), in order to facilitate earlier identification of monkeys at risk for poor social outcomes. Social classification was determined for N = 25 LS and N = 25 HS male monkeys that were 1-4 years of age. As part of a colony-wide assessment, these monkeys had previously undergone, as infants, tests of face recognition memory and the ability to respond appropriately to conspecific social signals. Monkeys later identified as LS vs. HS showed impairments in recognizing familiar vs. novel faces and in the species-typical adaptive ability to gaze avert to scenes of conspecific aggression. Additionally, multivariate logistic regression using infant social ability measures perfectly predicted later social classification of all N = 50 monkeys. These findings suggest that an early capacity to process important social information may account for differences in rhesus monkeys' motivation and competence to establish and maintain social relationships later in life. Further development of this model will facilitate identification of novel biological targets for intervention to improve social outcomes in at-risk young monkeys.

Autism and the Social Brain: The First-Year Puzzle

The atypical features of social perception and cognition observed in individuals with a diagnosis of autism have been explained in two different ways. First, domain-specific accounts are based on the assumption that these end-state symptoms result from specific impairments within component structures of the social brain network. Second, domain-general accounts hypothesize that rather than being localized, atypical brain structure and function are widespread, or hypothesize that the apparent social brain differences are the consequence of adaptations to earlier occurring widespread changes in brain function. Critical evidence for resolving this basic issue comes from prospective longitudinal studies of infants at risk for later diagnosis. We highlight selected studies from the newly emerging literature on infants at familial risk for autism to shed light on this issue. Despite multiple reports of possible alterations in brain function in the first year of life, overt behavioral symptoms do not emerge until the second year. Our review reveals only mixed support, within this very early period, for localized deficits in social brain network systems and instead favors the view that atypical development involving perceptual, attentional, motor, and social systems precede the emerging autism phenotype.

Examining the reinforcing value of stimuli within social and non-social contexts in children with and without high-functioning autism

One of the key diagnostic criteria for autism spectrum disorder includes impairments in social interactions. This study compared the extent to which boys with high-functioning autism and typically developing boys "value" engaging in activities with a parent or alone. Two different assessments that can empirically determine the relative reinforcing value of social and non-social stimuli were employed: paired-choice preference assessments and progressive-ratio schedules. There were no significant differences between boys with high-functioning autism and typically developing boys on either measure. Moreover, there was a strong correspondence in performance across these two measures for participants in each group. These results suggest that the relative reinforcing value of engaging in activities with a primary caregiver is not diminished for children with autism spectrum disorder.

Greater Pupil Size in Response to Emotional Faces as an Early Marker of Social-Communicative Difficulties in Infants at High Risk for Autism

When scanning faces, individuals with autism spectrum disorder (ASD) have shown reduced visual attention (e.g., less time on eyes) and atypical autonomic responses (e.g., heightened arousal). To understand how these differences might explain sub-clinical variability in social functioning, 9-month-olds, with or without a family history of ASD, viewed emotionally-expressive faces, and gaze and pupil diameter (a measure of autonomic activation) were recorded using eye-tracking. Infants at high-risk for ASD with no subsequent clinical diagnosis (HRA-) and low-risk controls (LRC) showed similar face scanning and attention to eyes and mouth. Attention was overall greater to eyes than mouth, but this varied as a function of the emotion presented. HRA- showed significantly larger pupil size than LRC. Correlations between scanning at 9 months, pupil size at 9 months, and 18-month social-communicative behavior, revealed positive associations between pupil size and attention to both face and eyes at 9 months in LRC, and a negative association between 9-month pupil size and 18-month social-communicative behavior in HRA-. The present findings point to heightened autonomic arousal in HRA-. Further, with greater arousal relating to worse social-communicative functioning at 18 months, this work points to a mechanism by which unaffected siblings might develop atypical social behavior.