Attention to social stimuli and facial identity recognition skills in autism spectrum disorder

Remotely supervised at-home delivery of taVNS for autism spectrum disorder: feasibility and initial efficacy

Background

Transcutaneous auricular vagus nerve stimulation (taVNS) has potential clinical application for autism spectrum disorder (ASD). At-home sessions are necessary to allow delivery of repeated sessions, and remove burden on patients for daily visits, and reduce costs of clinic delivery. Our objective was to validate a protocol for remote supervised administration for home delivery of taVNS using specially designed equipment and platform.

Methods

An open-label design was followed involving administration by caretakers to 12 patients with ASD (ages:7-16). Daily 1-h sessions over 2 weeks were administered under remote supervision. The primary outcome was feasibility, which was assessed by completion rate, stimulation tolerability, and confirmation of programmed stimulation delivery. The secondary measures were initial efficacy assessed by Childhood Anxiety Sensitivity Index-Revised (CASI-R), Parent Rated Anxiety Scale for Youth with ASD (PRAS-ASD), and Clinician Global Impression (CGI) scales. Sleep measures were also tracked using Cleveland Adolescent Sleep Questionnaire (CASQ).

Results

Across 132 sessions, we obtained an 88.5% completion rate. A total of 22 expected adverse events were reported with headache being the most common followed by transient pain, itchiness, and stinging at the electrode site. One subject dropped out of the study unrelated to the stimulation or the study. Average scores of anxiety (CASI-R, PRAS-ASD, and CGI) and sleepiness (CASQ) were all improved at the 2 week time point. While not powered to determine efficacy, benefits were suggested in this open label pilot.

Conclusion

Remotely supervised, proxy-administered, at-home delivery of taVNS is feasible in patients with ASD. Initial efficacy supports pursuing larger scale trials.

Integration of Facial Expression and Gaze Direction in Individuals with a High Level of Autistic Traits

Background. We investigated whether individuals with high levels of autistic traits integrate relevant communicative signals, such as facial expression, when decoding eye-gaze direction. Methods. Students with high vs. low scores on the Autism Spectrum Quotient (AQ) performed a task in which they responded to the eye directions of faces, presented on the left or the right side of a screen, portraying different emotional expressions. Results. In both groups, the identification of gaze direction was faster when the eyes were directed towards the center of the scene. However, in the low AQ group, this effect was larger for happy faces than for neutral faces or faces showing other emotional expressions, whereas participants from high AQ group were not affected by emotional expressions. Conclusions. These results suggest that individuals with more autistic traits may not integrate multiple communicative signals based on their emotional value.

Attention to live eye contact in adolescents with autism spectrum disorder

A number of studies have reported diminished attention to the eyes in individuals with autism spectrum disorder (ASD). These studies predominantly used static images of faces as stimuli. Recent studies, however, have shown enhanced response to eye contact in typically developing (TD) individuals when they observe a person in a live interaction. We investigated physiological orienting to perceived eye contact in adolescents with ASD and TD adolescents when they observed a person in live interaction or viewed a photograph of the same person's face. We measured heart rate (HR) deceleration as an index of attentional orienting. Adolescents with ASD, as well as TD adolescents, showed significant HR deceleration for the direct gaze compared to an averted gaze in the live condition, but not in the photographic condition. The results suggest an intact response to perceived eye contact in individuals with ASD during a live face-to-face interaction. LAY SUMMARY: Individuals with autism spectrum disorder (ASD) have a different eye gaze pattern when observing photographic faces. However, little is known about how individuals with ASD process a real person's face. We measured heart rate (HR) and found that adolescents with ASD showed the typical decline in HR when they made eye contact with a real person, which suggests that both groups of individuals directed their attention to eye contact in a live face-to-face interaction.

Autistic spectrum traits detection and early screening: A machine learning based eye movement study

PROBLEM

Autism spectrum disorders (ASD) are pervasive neurodevelopmental disorders and generally accompanied by social disorders, verbal or nonverbal communication defects, inability to concentrate and other negative symptoms that affect the autistic person's normal life. However, traditional screening methods are time-consuming and public health resources are limited.

METHODS

This study proposed a novel technique that combined eye-movement data and machine learning algorithms for predicting autistic traits. We converted raw eye movement data into features, trained and tested a model for early screening.

FINDINGS

In the preliminary experiment, 107 participants (average age = 24.84 ± 5.24 years) wore HTC Vive to watch a VR scene for 15-20 s. We explored eight classification models, among which the ensemble model performed best, with 0.73 accuracy, 0.68 precision, 0.81 recall, 0.74 F1-score, and an area under the curve of 0.90. And in the test experiment, 22 participants (average age = 12.68 ± 7.61 years) diagnosed as ASD took the experiment and the ensemble model showed a recall of 0.77. Eye movement data is an effectively distinguishable tool and we find that the proportion of time to observe figure and animal region continuously can distinguish participants with obvious and unobvious autistic traits effectively in the model.

CONCLUSION

This study focuses on the detection of autistic traits, and proposes a more objective and faster method for undertaking early screening, which provides possibilities to save precious time to intervene and alleviate its symptoms before making a definite diagnosis.

Impaired social attention detected through eye movements in children with early-onset epilepsy

OBJECTIVES

Children with early-onset epilepsy (CWEOE; epilepsy onset before 5 years) exhibit impaired social functioning, but social attention has not yet been examined. In this study we sought to explore visual attention via eye tracking as a component of social attention and examine its relationship with social functioning and Autism Spectrum Disorder (ASD) risk scores.

METHODS

Forty-seven CWEOE (3-63 months) and 41 controls (3-61 months) completed two eye-tracking tasks: (1) preference for social versus nonsocial naturalistic scenes, and (2) face region preference task. ASD risk was measured via the Modified Checklist for Autism in Toddlers or Conners Early Childhood Total Score. Social functioning was assessed via the Greenspan Social-Emotional Growth Chart, or Infant-Toddler Social & Emotional Assessment Competence Scale, or Conners Early Childhood Social Functioning Scale, depending on age. Fixation preferences for social scenes and eyes were compared between groups and evaluated by age and social functioning scores.

RESULTS

Regression analysis revealed that CWEOE viewed the social scene to a significantly less degree than controls. The greatest difference was found between the youngest CWEOE and controls. Fixation duration was independently and significantly related to social functioning scores. There were no significant differences between CWEOE and controls in the face scanning task, and there was no significant relationship between either task and ASD risk scores.

SIGNIFICANCE

CWEOE exhibit task-specific atypical social attention early in the course of the disease. This may be an early marker of impaired social development, and it suggests abnormal social brain development.

Investigating Gaze Behaviour of Children Diagnosed with Autism Spectrum Disorders in a Classroom Setting

A defining feature of ASD is atypical gaze behaviour, however, eye-tracking studies in ‘real-world’ settings are limited, and the possibility of improving gaze behaviour for ASD children is largely unexplored. This study investigated gaze behaviour of ASD and typically developing (TD) children in their classroom setting. Eye-tracking technology was used to develop and pilot an operant training tool to positively reinforce typical gaze behaviour towards faces. Visual and statistical analyses of eye-tracking data revealed different gaze behaviour patterns during live interactions for ASD and TD children depending on the interaction type. All children responded to operant training with longer looking times observed on face stimuli post training. The promising application of operant gaze training in ecologically valid settings is discussed.

Social Attention Deficits in Children With Autism Spectrum Disorder: Task Dependence of Objects vs. Faces Observation Bias

Social attention deficits represent a central impairment of patients suffering from autism spectrum disorder (ASD), but the nature of such deficits remains controversial. We compared visual attention regarding social (faces) vs. non-social stimuli (objects), in an ecological diagnostic context, in 46 children and adolescents divided in two groups: ASD (N = 23) and typical neurodevelopment (TD) (N = 23), matched for chronological age and intellectual performance. Eye-tracking measures of visual scanning, while exploring and describing scenes from three different tasks from the Autism Diagnostic Observation Schedule (ADOS), were analyzed: "Description of a Picture," "Cartoons," and "Telling a Story from a Book." Our analyses revealed a three-way interaction between Group, Task, and Social vs. Object Stimuli. We found a striking main effect of group and a task dependence of attentional allocation: while the TD attended first and longer to faces, ASD participants became similar to TD when they were asked to look at pictures while telling a story. Our results suggest that social attention allocation is task dependent, raising the question whether spontaneous attention deficits can be rescued by guiding goal-directed actions.

Atypical Inter-Network Deactivation Associated With the Posterior Default-Mode Network in Autism Spectrum Disorder

Previous studies have suggested that atypical deactivation of functional brain networks contributes to the complex cognitive and behavioral profile associated with autism spectrum disorder (ASD). However, these studies have not considered the temporal dynamics of deactivation mechanisms between the networks. In this study, we examined (a) mutual deactivation and (b) mutual activation-deactivation (i.e., anticorrelated) time-lag patterns between resting-state networks (RSNs) in young adults with ASD (n = 20) and controls (n = 20) by applying the recently defined dynamic lag analysis (DLA) method, which measures time-lag variations peak-by-peak between the networks. In order to achieve temporally accurate lag patterns, the brain imaging data was acquired with a fast functional magnetic resonance imaging (fMRI) sequence (TR = 100 ms). Group-level independent component analysis was used to identify 16 RSNs for the DLA. We found altered mutual deactivation timings in ASD in (a) three of the deactivated and (b) two of the transiently anticorrelated (activated-deactivated) RSN pairs, which survived the strict threshold for significance of surrogate data. Of the significant RSN pairs, 80% included the posterior default-mode network (DMN). We propose that temporally altered deactivation mechanisms, including timings and directionality, between the posterior DMN and RSNs mediating processing of socially relevant information may contribute to the ASD phenotype. LAY SUMMARY: To understand autistic traits on a neural level, we examined temporal fluctuations in information flow between brain regions in young adults with autism spectrum disorder (ASD) and controls. We used a fast neuroimaging procedure to investigate deactivation mechanisms between brain regions. We found that timings and directionality of communication between certain brain regions were temporally altered in ASD, suggesting atypical deactivation mechanisms associated with the posterior default-mode network.

Evidence of an Own-Age Bias in Facial Emotion Recognition for Adolescents With and Without Autism Spectrum Disorder

A common interpretation of the face-processing deficits associated with autism spectrum disorder (ASD) is that they arise from a failure to develop normative levels of perceptual expertise. One indicator of perceptual expertise for faces is the own-age bias, operationalized as a processing advantage for faces of one's own age, presumably due to more frequent contact and experience. This effect is especially evident in domains of face recognition memory but less commonly investigated in social-emotional expertise (e.g., facial emotion recognition; FER), where individuals with ASD have shown consistent deficits. In the present study, we investigated whether a FER task would elicit an own-age bias for individuals with and without ASD and explored how the magnitude of an own-age bias may differ as a function of ASD status and symptoms. Ninety-two adolescents (63 male) between the ages of 11 and 14 years completed the child- and adult-face subtests of a standardized FER task. Overall FER accuracy was found to differ by ASD severity, reflecting poorer performance for those with increased symptoms. Results also indicated that an own-age bias was evident, reflecting greater FER performance for child compared to adult faces, for all adolescents regardless of ASD status or symptoms. However, the strength of the observed own-age bias did not differ by ASD status or severity. Findings suggest that face processing abilities of adolescents with ASD may be influenced by experience with specific categories of stimuli, similar to their typically developing peers.

Saccade Latency Provides Evidence for Reduced Face Inversion Effects With Higher Autism Traits

Individuals on the autism spectrum are reported to show impairments in the processing of social information, including aspects of eye-movements towards faces. Abnormalities in basic-level visual processing are also reported. In the current study, we sought to determine if the latency of saccades made towards social targets (faces) in a natural scene as opposed to inanimate targets (cars) would be related to sub-clinical autism traits (ATs) in individuals drawn from a neurotypical population. The effect of stimulus inversion was also examined given that difficulties with processing inverted faces are thought to be a function of face expertise. No group differences in saccadic latency were established for face or car targets, regardless of image orientation. However, as expected, we found that individuals with higher autism-like traits did not demonstrate a saccadic face inversion effect, but those with lower autism-like traits did. Neither group showed a car inversion effect. Thus, these results suggest that neurotypical individuals with high autism-like traits also show anomalies in detecting and orienting to faces. In particular, the reduced saccadic face inversion effect established in these participants with high ATs suggests that speed of visual processing and orienting towards faces may be associated with the social difficulties found across the broader autism spectrum.

Attention Modification to Attenuate Facial Emotion Recognition Deficits in Children with Autism: A Pilot Study

Diminished attending to faces may contribute to the impairments in emotion recognition and expression in autism spectrum disorder (ASD). The current study evaluated the acceptability, feasibility, and preliminary efficacy of an attention modification intervention designed to attenuate deficits in facial emotion recognition (FER). During the 10-session experimental treatment, children (n = 8) with ASD watched dynamic videos of people expressing different emotions with the facial features highlighted to guide children's attention. Children and their parents generally rated the treatment as acceptable and helpful. Although FER improvement was not apparent on task-based measures, parents reported slight improvements and decreased socioemotional problems following treatment. Results suggest that further research on visual attention retraining for ASD, within an experimental therapeutic program, may be promising.

Combined frequency-tagging EEG and eye tracking reveal reduced social bias in boys with autism spectrum disorder

Developmental accounts of autism spectrum disorder (ASD) state that infants and children with ASD are spontaneously less attracted by and less proficient in processing social stimuli such as faces. This is hypothesized to partly underlie social communication difficulties in ASD. While in some studies a reduced preference for social stimuli has been shown in individuals with ASD, effect sizes are moderate and vary across studies, stimuli, and designs. Eye tracking, often the methodology of choice to study social preference, conveys information about overt orienting processes but conceals covert attention, possibly resulting in an underestimation of the effects. In this study, we recorded eye tracking and electroencephalography (EEG) during fast periodic visual stimulation to address this issue. We tested 21 boys with ASD (8-12 years old) and 21 typically developing (TD) control boys, matched for age and IQ. Streams of variable images of faces were presented at 6 Hz alongside images of houses presented at 7.5 Hz or vice versa, while children were engaged in an orthogonal task. While frequency-tagged neural responses were larger in response to faces than simultaneously presented houses in both groups, this effect was much larger in TD boys than in boys with ASD. This group difference in saliency of social versus non-social processing is significant after 5 sec of stimulus presentation and holds throughout the entire trial. Although there was no interaction between group and stimulus category for simultaneously recorded eye-tracking data, eye tracking and EEG measures were strongly correlated. We conclude that frequency-tagging EEG, allowing monitoring of both overt and covert processes, provides a fast, objective and reliable measure of decreased preference for social information in ASD.

Initial eye gaze to faces and its functional consequence on face identification abilities in autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder defined and diagnosed by core deficits in social communication and the presence of restricted and repetitive behaviors. Research on face processing suggests deficits in this domain in ASD but includes many mixed findings regarding the nature and extent of these differences. The first eye movement to a face has been shown to be highly informative and sufficient to achieve high performance in face identification in neurotypical adults. The current study focused on this critical moment shown to be essential in the process of face identification.

METHODS

We applied an established eye-tracking and face identification paradigm to comprehensively characterize the initial eye movement to a face and test its functional consequence on face identification performance in adolescents with and without ASD (n = 21 per group), and in neurotypical adults. Specifically, we presented a series of faces and measured the landing location of the first saccade to each face, while simultaneously measuring their face identification abilities. Then, individuals were guided to look at specific locations on the face, and we measured how face identification performance varied as a function of that location. Adolescent participants also completed a more traditional measure of face identification which allowed us to more fully characterize face identification abilities in ASD.

RESULTS

Our results indicate that the location of the initial look to faces and face identification performance for briefly presented faces are intact in ASD, ruling out the possibility that deficits in face perception, at least in adolescents with ASD, begin with the initial eye movement to the face. However, individuals with ASD showed impairments on the more traditional measure of face identification.

CONCLUSION

Together, the observed dissociation between initial, rapid face perception processes, and other measures of face perception offers new insights and hypotheses related to the timing and perceptual complexity of face processing and how these specific aspects of face identification may be disrupted in ASD.

Examining How Types of Object Distractors Distinctly Compete for Facial Attention in Autism Spectrum Disorder Using Eye Tracking

Social motivation theory states that individuals with ASD find social stimuli less rewarding (Chevallier et al. in Trends Cognit Sci 16(4):231-239, 2012). An alternative theory suggests that competition from circumscribed interests (CIs) may better account for diminished social attention (Sasson et al. in Autism Res 1(1):31-42, 2008). This study evaluated both theories in children diagnosed with ASD (n = 16) and a group of TD children (n = 20) using eye tracking and demonstrated that distractor type only impacted the proportion of dwell time on faces in the TD group, but not the ASD group. These results provide support for the social motivation theory because gaze duration for faces among children with ASD was diminished regardless of whether the non-social stimuli presented was a CI or control object.

What Can Eye Movements Tell Us about Subtle Cognitive Processing Differences in Autism?

Autism spectrum disorder (ASD) is neurodevelopmental condition principally characterised by impairments in social interaction and communication, and repetitive behaviours and interests. This article reviews the eye movement studies designed to investigate the underlying sampling or processing differences that might account for the principal characteristics of autism. Following a brief summary of a previous review chapter by one of the authors of the current paper, a detailed review of eye movement studies investigating various aspects of processing in autism over the last decade will be presented. The literature will be organised into sections covering different cognitive components, including language and social communication and interaction studies. The aim of the review will be to show how eye movement studies provide a very useful on-line processing measure, allowing us to account for observed differences in behavioural data (accuracy and reaction times). The subtle processing differences that eye movement data reveal in both language and social processing have the potential to impact in the everyday communication domain in autism.

Attention to faces in social context in children with neurofibromatosis type 1

AIM

To examine visual attention to faces within social scenes in children with neurofibromatosis type 1 (NF1) and typically developing peers.

METHOD

Using eye-tracking technology we investigated the time taken to fixate on a face and the percentage of time spent attending to faces relative to the rest of the screen within social scenes in 24 children with NF1 (17 females, seven males; mean age 10y 4mo [SD 1y 9mo]). Results were compared with those of 24 age-matched typically developing controls (11 females, 13 males; mean age 10y 3mo [SD 2y]).

RESULTS

There was no significant between-group differences in time taken to initially fixate on a face (p=0.617); however, children with NF1 spent less time attending to faces within scenes than controls (p=0.048). Decreased attention to faces was associated with elevated autism traits in children with NF1.

INTERPRETATION

Children with NF1 spend less time attending to faces than typically developing children when presented in social scenes. Our findings contribute to a growing body of literature suggesting that abnormal face processing is a key aspect of the social-cognitive phenotype of NF1 and appears to be related to autism spectrum disorder traits. Clinicians should consider the impact of reduced attention to faces when designing and implementing treatment programmes for social dysfunction in this population.

WHAT THIS PAPER ADDS

Children with neurofibromatosis type 1 (NF1) demonstrated atypical gaze behaviour when attending to faces. NF1 gaze behaviour was characterized by normal initial fixation on faces but shorter face dwell time. Decreased attention to faces was associated with elevated autism traits in the sample with NF1.

Link Between Facial Identity and Expression Abilities Suggestive of Origins of Face Impairments in Autism: Support for the Social-Motivation Hypothesis

Individuals with autism spectrum disorder (ASD) often have difficulties with processing identity and expression in faces. This is at odds with influential models of face processing that propose separate neural pathways for the identity and expression domains. The social-motivation hypothesis of ASD posits a lack of visual experience with faces as the root cause of face impairments in autism. A direct prediction is that identity and expression abilities should be related in ASD, reflecting the common origin of face impairment in this population. We tested adults with and without ASD ( ns = 34) in identity and expression tasks. Our results showed that performance in the two domains was significantly correlated in the ASD group but not in the comparison group. These results suggest that the most likely origin for face impairments in ASD stems from the input stage impacting development of identity and expression domains alike, consistent with the social-motivation hypothesis.

Maternal Interactive Behaviours in Parenting Children with Williams Syndrome and Autism Spectrum Disorder: Relations with Emotional/Behavioural Problems

This study compared maternal responsiveness to children with two neurodevelopmental disorders sharing different but, in some cases, overlapping social phenotypes-Williams syndrome (WS) and autism spectrum disorder (ASD)-and explored the relations between maternal responsiveness and child emotional/behavioural problems (EBP). The sample included 16 pre-schoolers with WS and 43 with ASD, and their mothers. Responsiveness was assessed during a mother-child interaction task. Mothers completed the CBCL 1½-5, providing a measure of EBP. No significant differences emerged between groups, and most dyads were characterized by less responsive behaviours. Maternal responsiveness proved related to child developmental age, but not with EBP. These results provide further insight into the rearing environment of children with neurodevelopmental disorders, highlighting the need for early relationship-based interventions.

Gaze Toward Naturalistic Social Scenes by Individuals With Intellectual and Developmental Disabilities: Implications for Augmentative and Alternative Communication Designs

PURPOSE

A striking characteristic of the social communication deficits in individuals with autism is atypical patterns of eye contact during social interactions. We used eye-tracking technology to evaluate how the number of human figures depicted and the presence of sharing activity between the human figures in still photographs influenced visual attention by individuals with autism, typical development, or Down syndrome. We sought to examine visual attention to the contents of visual scene displays, a growing form of augmentative and alternative communication support.

METHOD

Eye-tracking technology recorded point-of-gaze while participants viewed 32 photographs in which either 2 or 3 human figures were depicted. Sharing activities between these human figures are either present or absent. The sampling rate was 60 Hz; that is, the technology gathered 60 samples of gaze behavior per second, per participant. Gaze behaviors, including latency to fixate and time spent fixating, were quantified.

RESULTS

The overall gaze behaviors were quite similar across groups, regardless of the social content depicted. However, individuals with autism were significantly slower than the other groups in latency to first view the human figures, especially when there were 3 people depicted in the photographs (as compared with 2 people). When participants' own viewing pace was considered, individuals with autism resembled those with Down syndrome.

CONCLUSION

The current study supports the inclusion of social content with various numbers of human figures and sharing activities between human figures into visual scene displays, regardless of the population served. Study design and reporting practices in eye-tracking literature as it relates to autism and Down syndrome are discussed.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.6066545.

Empathy and face processing in adults with and without autism spectrum disorder

Many factors contribute to social difficulties in individuals with autism spectrum disorder (ASD). The goal of the present work was to determine whether atypicalities in how individuals with ASD process static, socially engaging faces persist when nonrigid facial motion cues are present. We also sought to explore the relationships between various face processing abilities and individual differences in autism symptom severity and traits such as empathy. Participants included 16 adults with ASD without intellectual impairment and 16 sex- and age-matched controls. Mean Verbal IQ was comparable across groups [t(30) = 0.70, P = 0.49]. The two groups responded similarly to many of the experimental manipulations; however, relative to controls, participants with ASD responded more slowly to dynamic expressive faces, even when no judgment was required; were less accurate at identity matching with static and dynamic faces; and needed more time to make identity and expression judgments [F(1, 30) ≥ 6.37, P ≤ 0.017, η_p²  ≥ 0.175 in all cases], particularly when the faces were moving [F(1, 30) = 3.40, P = 0.072, η_p²  = 0.104]. In the full sample, as social autistic traits increased and empathic skills declined, participants needed more time to judge static identity, and static or dynamic expressions [0.43 < |r_s | < 0.56]. The results suggest that adults with ASD show general impairments in face and motion processing and support the view that an examination of individual variation in particular personality traits and abilities is important for advancing our understanding of face perception. Autism Res 2018, 11: 942-955. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Our findings suggest that people with ASD have problems processing expressive faces, especially when seen in motion. It is important to learn who is most at risk for face processing problems, given that in the general population such problems appear to be linked to impaired social skills and empathy. By studying relationships between different abilities and traits, we may be able to find better ways to diagnose and support all people on the autism spectrum.

Social Attention, Joint Attention and Sustained Attention in Autism Spectrum Disorder and Williams Syndrome: Convergences and Divergences

There is limited knowledge on shared and syndrome-specific attentional profiles in autism spectrum disorder (ASD) and Williams syndrome (WS). Using eye-tracking, we examined attentional profiles of 35 preschoolers with ASD, 22 preschoolers with WS and 20 typically developing children across social and non-social dimensions of attention. Children with ASD and those with WS presented with overlapping deficits in spontaneous visual engagement with the target of others' attention and in sustained attention. Children with ASD showed syndrome-specific abnormalities in monitoring and following a person's referential gaze, as well as a lack of preferential attention to social stimuli. Children with ASD and WS present with shared as well as syndrome-specific abnormalities across social and non-social dimensions of attention.

The impact of atypical sensory processing on social impairments in autism spectrum disorder

Altered sensory processing has been an important feature of the clinical descriptions of autism spectrum disorder (ASD). There is evidence that sensory dysregulation arises early in the progression of ASD and impacts social functioning. This paper reviews behavioral and neurobiological evidence that describes how sensory deficits across multiple modalities (vision, hearing, touch, olfaction, gustation, and multisensory integration) could impact social functions in ASD. Theoretical models of ASD and their implications for the relationship between sensory and social functioning are discussed. Furthermore, neural differences in anatomy, function, and connectivity of different regions underlying sensory and social processing are also discussed. We conclude that there are multiple mechanisms through which early sensory dysregulation in ASD could cascade into social deficits across development. Future research is needed to clarify these mechanisms, and specific focus should be given to distinguish between deficits in primary sensory processing and altered top-down attentional and cognitive processes.

Emotion Perception or Social Cognitive Complexity: What Drives Face Processing Deficits in Autism Spectrum Disorder?

Some, but not all, relevant studies have revealed face processing deficits among those with autism spectrum disorder (ASD). In particular, deficits are revealed in face processing tasks that involve emotion perception. The current study examined whether either deficits in processing emotional expression or deficits in processing social cognitive complexity drive face processing deficits in ASD. We tested adults with and without ASD on a battery of face processing tasks that varied with respect to emotional expression processing and social cognitive complexity. Results revealed significant group differences on tasks involving emotional expression processing, but typical performance on a non-emotional but socially complex task. These results support an emotion processing rather than a social complexity explanation for face processing deficits in ASD.

Conscious and Non-conscious Representations of Emotional Faces in Asperger's Syndrome

Several neuroimaging studies have suggested that the low spatial frequency content in an emotional face mainly activates the amygdala, pulvinar, and superior colliculus especially with fearful faces(1-3). These regions constitute the limbic structure in non-conscious perception of emotions and modulate cortical activity either directly or indirectly(2). In contrast, the conscious representation of emotions is more pronounced in the anterior cingulate, prefrontal cortex, and somatosensory cortex for directing voluntary attention to details in faces(3,4). Asperger's syndrome (AS)(5,6) represents an atypical mental disturbance that affects sensory, affective and communicative abilities, without interfering with normal linguistic skills and intellectual ability. Several studies have found that functional deficits in the neural circuitry important for facial emotion recognition can partly explain social communication failure in patients with AS(7-9). In order to clarify the interplay between conscious and non-conscious representations of emotional faces in AS, an EEG experimental protocol is designed with two tasks involving emotionality evaluation of either photograph or line-drawing faces. A pilot study is introduced for selecting face stimuli that minimize the differences in reaction times and scores assigned to facial emotions between the pretested patients with AS and IQ/gender-matched healthy controls. Information from the pretested patients was used to develop the scoring system used for the emotionality evaluation. Research into facial emotions and visual stimuli with different spatial frequency contents has reached discrepant findings depending on the demographic characteristics of participants and task demands(2). The experimental protocol is intended to clarify deficits in patients with AS in processing emotional faces when compared with healthy controls by controlling for factors unrelated to recognition of facial emotions, such as task difficulty, IQ and gender.

Social attention in ASD: A review and meta-analysis of eye-tracking studies

Determining whether social attention is reduced in Autism Spectrum Disorder (ASD) and what factors influence social attention is important to our theoretical understanding of developmental trajectories of ASD and to designing targeted interventions for ASD. This meta-analysis examines data from 38 articles that used eye-tracking methods to compare individuals with ASD and TD controls. In this paper, the impact of eight factors on the size of the effect for the difference in social attention between these two groups are evaluated: age, non-verbal IQ matching, verbal IQ matching, motion, social content, ecological validity, audio input and attention bids. Results show that individuals with ASD spend less time attending to social stimuli than typically developing (TD) controls, with a mean effect size of 0.55. Social attention in ASD was most impacted when stimuli had a high social content (showed more than one person). This meta-analysis provides an opportunity to survey the eye-tracking research on social attention in ASD and to outline potential future research directions, more specifically research of social attention in the context of stimuli with high social content.

Neural and cortisol responses during play with human and computer partners in children with autism

Children with autism spectrum disorder (ASD) exhibit impairment in reciprocal social interactions, including play, which can manifest as failure to show social preference or discrimination between social and nonsocial stimuli. To explore mechanisms underlying these deficits, we collected salivary cortisol from 42 children 8-12 years with ASD or typical development during a playground interaction with a confederate child. Participants underwent functional MRI during a prisoner's dilemma game requiring cooperation or defection with a human (confederate) or computer partner. Search region of interest analyses were based on previous research (e.g. insula, amygdala, temporal parietal junction-TPJ). There were significant group differences in neural activation based on partner and response pattern. When playing with a human partner, children with ASD showed limited engagement of a social salience brain circuit during defection. Reduced insula activation during defection in the ASD children relative to TD children, regardless of partner type, was also a prominent finding. Insula and TPJ BOLD during defection was also associated with stress responsivity and behavior in the ASD group under playground conditions. Children with ASD engage social salience networks less than TD children during conditions of social salience, supporting a fundamental disturbance of social engagement.

Enhanced ERPs to visual stimuli in unaffected male siblings of ASD children

Autism spectrum disorders are characterized by deficits in social and communication abilities. While unaffected relatives lack severe deficits, milder impairments have been reported in some first-degree relatives. The present study sought to verify whether mild deficits in face perception are evident among the unaffected younger siblings of children with ASD. Children between 6-9 years of age completed a face-recognition task and a passive viewing ERP task with face and house stimuli. Sixteen children were typically developing with no family history of ASD, and 17 were unaffected children with an older sibling with ASD. Findings indicate that, while unaffected siblings are comparable to controls in their face-recognition abilities, unaffected male siblings in particular show relatively enhanced P100 and P100-N170 peak-to-peak amplitude responses to faces and houses. Enhanced ERPs among unaffected male siblings is discussed in relation to potential differences in neural network recruitment during visual and face processing.

Face and object discrimination in autism, and relationship to IQ and age

The current study tested fine discrimination of upright and inverted faces and objects in adolescents with Autism Spectrum Disorder (ASD) as compared to age- and IQ-matched controls. Discrimination sensitivity was tested using morphed faces and morphed objects, and all stimuli were equated in low-level visual characteristics (luminance, contrast, spatial frequency make-up). Participants with ASD exhibited slight, non-significant impairments in discrimination sensitivity for faces, yet significantly enhanced discrimination sensitivity for objects. The ASD group also showed a protracted development of face and object inversion effects. Finally, for ASD participants, face sensitivity improved with increasing IQ while object sensitivity improved with age. By contrast, for controls, face sensitivity improved with age, but neither face nor object sensitivity was influenced by IQ. These findings suggest that individuals with ASD follow a qualitatively different path in the development of face and object processing abilities.

A systematic review and meta-analysis of eye-tracking studies in children with autism spectrum disorders

Aberrant eye gaze mechanisms have been implicated in autism spectrum disorders (ASD). Studies of eye movements in children with ASD reveal diminished eye gaze duration and lack of specific eye gaze fixation to the eyes and/or mouth compared with controls. However, findings to date have been contradictory. We examined eye-tracking studies on face processing in children with ASD and conducted meta-analyses to examine whether these children demonstrate atypical fixation on primary facial regions. Twenty eye-tracking studies in children with ASD were reviewed, of which the results from 14 studies were incorporated in the meta-analyses that evaluated fixation duration on (i) eyes (eight studies) and (ii) mouth (six studies). The results reveal that children with ASD have significantly reduced gaze fixation to the eye region of faces. The results of the meta-analyses indicate that ASD patients have significant impairments in gaze fixation to the eyes. On the other hand, no significant difference was uncovered in terms of fixation to the mouth region; however, this finding needs to be interpreted with caution because of the significant heterogeneity in the mouth fixation studies. The findings of this meta-analysis add further clarity to an expanding literature and suggest that specific eye gaze fixation to the eye region may represent a robust biomarker for the condition. The heterogeneity associated with the mouth fixation data precludes any definitive statement as to the robustness of these findings.

Reduced face aftereffects in autism are not due to poor attention

This study aimed to determine why face identity aftereffects are diminished in children with autism, relative to typical children. To address the possibility that reduced face aftereffects might reflect reduced attention to adapting stimuli, we investigated the consequence of controlling attention to adapting faces during a face identity aftereffect task in children with autism and typical children. We also included a size-change between adaptation and test stimuli to determine whether the reduced aftereffects reflect atypical adaptation to low- or higher-level stimulus properties. Results indicated that when attention was controlled and directed towards adapting stimuli, face identity aftereffects in children with autism were significantly reduced relative to typical children. This finding challenges the notion that atypicalities in the quality and/or quantity of children's attention during adaptation might account for group differences previously observed in this paradigm. Additionally, evidence of diminished face identity aftereffects despite a stimulus size change supports an adaptive processing atypicality in autism that extends beyond low-level, retinotopically coded stimulus properties. These findings support the notion that diminished face aftereffects in autism reflect atypicalities in adaptive norm-based coding, which could also contribute to face processing difficulties in this group.

Reevaluating the selectivity of face-processing difficulties in children and adolescents with autism

There are few direct examinations of whether face-processing difficulties in autism are disproportionate to difficulties with other complex non-face stimuli. Here we examined discrimination ability and memory for faces, cars, and inverted faces in children and adolescents with and without autism. Results showed that, relative to typical children, the difficulties of children and adolescents with autism were not limited to, or disproportionately severe for, faces. Rather, these participants demonstrated significant difficulties in remembering and discriminating between faces and cars. This lack of face selectivity is inconsistent with prominent theories that attribute face-processing difficulties in autism to fundamental problems with social motivation or social attention. Instead, our results are consistent with a more pervasive perceptual atypicality that may affect autistic processing of non-face stimuli as well as face stimuli.

Visual Scanning Patterns during the Dimensional Change Card Sorting Task in Children with Autism Spectrum Disorder

Impaired cognitive flexibility in children with autism spectrum disorder (ASD) has been reported in previous literature. The present study explored ASD children's visual scanning patterns during the Dimensional Change Card Sorting (DCCS) task using eye-tracking technique. ASD and typical developing (TD) children completed the standardized DCCS procedure on the computer while their eye movements were tracked. Behavioral results confirmed previous findings on ASD children's deficits in executive function. ASD children's visual scanning patterns also showed some specific underlying processes in the DCCS task compared to TD children. For example, ASD children looked shorter at the correct card in the postswitch phase and spent longer time at blank areas than TD children did. ASD children did not show a bias to the color dimension as TD children did. The correlations between the behavioral performance and eye moments were also discussed.

Visual scan paths and recognition of facial identity in autism spectrum disorder and typical development

Background

Previous research suggests that many individuals with autism spectrum disorder (ASD) have impaired facial identity recognition, and also exhibit abnormal visual scanning of faces. Here, two hypotheses accounting for an association between these observations were tested: i) better facial identity recognition is associated with increased gaze time on the Eye region; ii) better facial identity recognition is associated with increased eye-movements around the face.

Methodology and Principal Findings

Eye-movements of 11 children with ASD and 11 age-matched typically developing (TD) controls were recorded whilst they viewed a series of faces, and then completed a two alternative forced-choice recognition memory test for the faces. Scores on the memory task were standardized according to age. In both groups, there was no evidence of an association between the proportion of time spent looking at the Eye region of faces and age-standardized recognition performance, thus the first hypothesis was rejected. However, the ‘Dynamic Scanning Index’ – which was incremented each time the participant saccaded into and out of one of the core-feature interest areas – was strongly associated with age-standardized face recognition scores in both groups, even after controlling for various other potential predictors of performance.

Conclusions and Significance

In support of the second hypothesis, results suggested that increased saccading between core-features was associated with more accurate face recognition ability, both in typical development and ASD. Causal directions of this relationship remain undetermined.

Face identity recognition in autism spectrum disorders: a review of behavioral studies

Face recognition--the ability to recognize a person from their facial appearance--is essential for normal social interaction. Face recognition deficits have been implicated in the most common disorder of social interaction: autism. Here we ask: is face identity recognition in fact impaired in people with autism? Reviewing behavioral studies we find no strong evidence for a qualitative difference in how facial identity is processed between those with and without autism: markers of typical face identity recognition, such as the face inversion effect, seem to be present in people with autism. However, quantitatively--i.e., how well facial identity is remembered or discriminated--people with autism perform worse than typical individuals. This impairment is particularly clear in face memory and in face perception tasks in which a delay intervenes between sample and test, and less so in tasks with no memory demand. Although some evidence suggests that this deficit may be specific to faces, further evidence on this question is necessary.

Individual differences in the ability to recognise facial identity are associated with social anxiety

Previous research has been concerned with the relationship between social anxiety and the recognition of face expression but the question of whether there is a relationship between social anxiety and the recognition of face identity has been neglected. Here, we report the first evidence that social anxiety is associated with recognition of face identity, across the population range of individual differences in recognition abilities. Results showed poorer face identity recognition (on the Cambridge Face Memory Test) was correlated with a small but significant increase in social anxiety (Social Interaction Anxiety Scale) but not general anxiety (State-Trait Anxiety Inventory). The correlation was also independent of general visual memory (Cambridge Car Memory Test) and IQ. Theoretically, the correlation could arise because correct identification of people, typically achieved via faces, is important for successful social interactions, extending evidence that individuals with clinical-level deficits in face identity recognition (prosopagnosia) often report social stress due to their inability to recognise others. Equally, the relationship could arise if social anxiety causes reduced exposure or attention to people's faces, and thus to poor development of face recognition mechanisms.

Recognition of own- and other-race faces in autism spectrum disorders

Empirical data regarding the extent of face recognition abnormalities in autism spectrum disorder (ASD) is inconsistent. Here, 27 ASD and 47 typically developing (TD) children completed an immediate two-alternative forced-choice identity matching task. We contrasted recognition of own- and other-race faces, and, counter to prediction, we found a typical advantage for recognizing own- over other-race faces in both the ASD and TD groups. In addition, ASD and TD groups responded similarly to stimulus manipulations (use of identical or different photographs for identity matching and cropping stimuli to remove hair information). However, age-standardized scores varied widely within the ASD sample, and a subgroup of ASD participants with impaired face recognition did not exhibit a significant own-race recognition advantage. An explanation regarding early experience with faces is considered, and implications for research of individual variation within ASD are discussed.