Developmental changes in face visual scanning in autism spectrum disorder as assessed by data-based analysis

Temporal progression of pupil dilation and gaze behavior to emotion expressions in preschoolers with autism spectrum disorder

Previous work has shown divergent pupil dilation (PD) and gaze behavior in individuals with autism spectrum disorder (ASD), which may relate to the development of social difficulties in early life. Here, we investigated temporal dynamics of both phenotypes during naturalistic videos of a person displaying facial emotion expressions in 61 autistic and 61 non-autistic preschoolers. PD was segmented into three serial time components derived from a principal component analysis. Growth curve analysis was applied to analyze changes in looking time on eye and mouth regions over time. Groups did not differ in PD time components. Growth curve analysis revealed initially shorter looking times on the eyes and longer looking times on the mouth in autistic versus non-autistic preschoolers. However, a reversion of this pattern was observed over time, suggesting a delayed compensatory increase in eye attention during prolonged viewing periods in autistic children. Positive and negative associations of PD components and gaze behavior over time indicated a dynamic temporal relationship during emotion viewing. Our findings emphasize the need to apply time-sensitive measures in ecologically valid research, which may index etiological mechanisms of social difficulties in ASD.

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

Introduction

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

Methods

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

Results

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

Conclusion

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

Characteristic fixation biases in Super-Recognizers

Neurotypical observers show large and reliable individual differences in gaze behavior along several semantic object dimensions. Individual gaze behavior toward faces has been linked to face identity processing, including that of neurotypical observers. Here, we investigated potential gaze biases in Super-Recognizers (SRs), individuals with exceptional face identity processing skills. Ten SRs, identified with a novel conservative diagnostic framework, and 43 controls freely viewed 700 complex scenes depicting more than 5000 objects. First, we tested whether SRs and controls differ in fixation biases along four semantic dimensions: faces, text, objects being touched, and bodies. Second, we tested potential group differences in fixation biases toward eyes and mouths. Finally, we tested whether SRs fixate closer to the theoretical optimal fixation point for face identification. SRs showed a stronger gaze bias toward faces and away from text and touched objects, starting from the first fixation onward. Further, SRs spent a significantly smaller proportion of first fixations and dwell time toward faces on mouths but did not differ in dwell time or first fixations devoted to eyes. Face fixation of SRs also fell significantly closer to the theoretical optimal fixation point for identification, just below the eyes. Our findings suggest that reliable superiority for face identity processing is accompanied by early fixation biases toward faces and preferred saccadic landing positions close to the theoretical optimum for face identification. We discuss future directions to investigate the functional basis of individual fixation behavior and face identity processing ability.

Gaze and social functioning associations in autism spectrum disorder: A systematic review and meta-analysis

Autism spectrum disorder (ASD) is characterized by significant social functioning impairments, including (but not limited to) emotion recognition, mentalizing, and joint attention. Despite extensive investigation into the correlates of social functioning in ASD, only recently has there been focus on the role of low‐level sensory input, particularly visual processing. Extensive gaze deficits have been described in ASD, from basic saccadic function through to social attention and the processing of complex biological motion. Given that social functioning often relies on accurately processing visual information, inefficient visual processing may contribute to the emergence and sustainment of social functioning difficulties in ASD. To explore the association between measures of gaze and social functioning in ASD, a systematic review and meta‐analysis was conducted. A total of 95 studies were identified from a search of CINAHL Plus, Embase, OVID Medline, and psycINFO databases in July 2021. Findings support associations between increased gaze to the face/head and eye regions with improved social functioning and reduced autism symptom severity. However, gaze allocation to the mouth appears dependent on social and emotional content of scenes and the cognitive profile of participants. This review supports the investigation of gaze variables as potential biomarkers of ASD, although future longitudinal studies are required to investigate the developmental progression of this relationship and to explore the influence of heterogeneity in ASD clinical characteristics.

Eye-Tracking Studies in Adults with Autism Spectrum Disorder: A Systematic Review and Meta-analysis

Eye-tracking studies have shown potential in effectively discriminating between autism spectrum disorder (ASD) and non-ASD groups. The main objective of the present study was to conduct a systematic review and meta-analysis of eye-tracking studies in adults with ASD. A total of 22 studies were included for meta-analysis. Eyes and Non-Social regions proved better for discriminating between ASD and non-ASD adults, while fixation duration seems to be the outcome to choose. Active engaged tasks seem to reduce differences between ASD and non-ASD adults, regardless of the emotional content of the stimuli/task. Proportional fixation duration on eyes and non-social areas in non-active tasks (e.g. free viewing) seems to be the best eye-tracking design for increasing the sensitivity and specificity in ASD adults.

New Technologies as Promising Tools for Assessing Facial Emotion Expressions Impairments in ASD: A Systematic Review

The ability to recognize and express emotions from facial expressions are essential for successful social interactions. Facial Emotion Recognition (FER) and Facial Emotion Expressions (FEEs), both of which seem to be impaired in Autism Spectrum Disorders (ASD) and contribute to socio-communicative difficulties, participate in the diagnostic criteria for ASD. Only a few studies have focused on FEEs processing and the rare behavioral studies of FEEs in ASD have yielded mixed results. Here, we review studies comparing the production of FEEs between participants with ASD and non-ASD control subjects, with a particular focus on the use of automatic facial expression analysis software. A systematic literature search in accordance with the PRISMA statement identified 20 reports published up to August 2020 concerning the use of new technologies to evaluate both spontaneous and voluntary FEEs in participants with ASD. Overall, the results highlight the importance of considering socio-demographic factors and psychiatric co-morbidities which may explain the previous inconsistent findings, particularly regarding quantitative data on spontaneous facial expressions. There is also reported evidence for an inadequacy of FEEs in individuals with ASD in relation to expected emotion, with a lower quality and coordination of facial muscular movements. Spatial and kinematic approaches to characterizing the synchrony, symmetry and complexity of facial muscle movements thus offer clues to identifying and exploring promising new diagnostic targets. These findings have allowed hypothesizing that there may be mismatches between mental representations and the production of FEEs themselves in ASD. Such considerations are in line with the Facial Feedback Hypothesis deficit in ASD as part of the Broken Mirror Theory, with the results suggesting impairments of neural sensory-motor systems involved in processing emotional information and ensuring embodied representations of emotions, which are the basis of human empathy. In conclusion, new technologies are promising tools for evaluating the production of FEEs in individuals with ASD, and controlled studies involving larger samples of patients and where possible confounding factors are considered, should be conducted in order to better understand and counter the difficulties in global emotional processing in ASD.

Developmental changes in attention to social information from childhood to adolescence in autism spectrum disorders: a comparative study

BACKGROUND

Elucidating developmental changes in the symptoms of autism spectrum disorder (ASD) is important to support individuals with ASD. However, no report has clarified the developmental changes in attention to social information for a broad age range. The aim of this study was to investigate the developmental changes in attention to social information from early childhood to adolescence in individuals with ASD and typically developed (TD) children.

METHODS

We recruited children with ASD (n = 83) and TD participants (n = 307) between 2 and 18 years of age. Using the all-in-one-eye-tracking system, Gazefinder, we measured the percentage fixation time allocated to areas of interest (AoIs) depicted in movies (the eyes and mouth in movies of a human face with/without mouth motion, upright and inverted biological motion in movies showing these stimuli simultaneously, people and geometry in preference paradigm movies showing these stimuli simultaneously, and objects with/without finger-pointing in a movie showing a woman pointing toward an object). We conducted a three-way analysis of variance, 2 (diagnosis: ASD and TD) by 2 (sex: male and female) by 3 (age group: 0-5, 6-11, and 12-18 years) and locally weighted the scatterplot smoothing (LOESS) regression curve on each AoI.

RESULTS

In the face stimuli, the percentage fixation time to the eye region for the TD group increased with age, whereas the one for the ASD group did not. In the ASD group, the LOESS curves of the gaze ratios at the eye region increased up to approximately 10 years of age and thereafter tended to decrease. For the percentage fixation time to the people region in the preference paradigm, the ASD group gazed more briefly at people than did the TD group.

LIMITATIONS

It is possible that due to the cross-sectional design, the degree of severity and of social interest might have differed according to the subjects' age.

CONCLUSIONS

There may be qualitative differences in abnormal eye contact in ASD between individuals in early childhood and those older than 10 years.

Attenuated relationship between salivary oxytocin levels and attention to social information in adolescents and adults with autism spectrum disorder: a comparative study

BACKGROUND

Previous research studies have assessed the relationship between attention to social information and peripheral (e.g., plasma and salivary) oxytocin (OT) levels in typically developing (TD) children and children with autism spectrum disorder (ASD). A relationship between them was observed in TD children, but not in children with ASD. However, this relationship remains unexamined in other age groups. To clarify whether this lack of association is maintained throughout development in individuals with ASD, we aimed to assess the relationship between salivary OT levels and attention to social information in adolescents and adults with and without ASD.

METHODS

We recruited male adolescents and adults with ASD (n = 17) and TD participants (n = 24). Using the all-in-one eye-tracking system Gazefinder, we measured the percentage fixation time allocated to social information. We also measured the salivary OT levels and Autism Spectrum Quotient (AQ) of participants. Subsequently, we confirmed group differences and conducted a correlation analysis to investigate the relationships between these three measures.

RESULTS

Salivary OT levels did not show any significant difference between the ASD and TD groups and were negatively correlated with the AQ in the whole-group analysis, but not in within-group analysis. Individuals with ASD had significantly lower percentage fixation times than did TD individuals for eye regions in human faces with/without mouth motion, for upright biological motion, and for people regions in the people and geometry movies. The percentage of fixation for geometric shapes in the people and geometry movies was significantly higher in the ASD than in the TD group. In the TD group, salivary OT levels were positively correlated with percentage fixation times for upright biological motion and people and negatively correlated with inverted biological motion and geometry. However, no significant correlations were found in the ASD group.

CONCLUSIONS

Our exploratory results suggest that salivary OT levels in adolescents and adults with ASD are less indicative of attention to social stimuli than they are in TD adolescents and adults. It is suggested that their association is slightly weaker in adolescents and adults with ASD and that this attenuated relationship appears to be maintained throughout development.

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.