"Look who's talking!" Gaze Patterns for Implicit and Explicit Audio-Visual Speech Synchrony Detection in Children With High-Functioning Autism

Neural correlates of audiovisual speech synchrony perception and its relationship with autistic traits

The anterior insula (AI) has the central role in coordinating attention and integrating information from multiple sensory modalities. AI dysfunction may contribute to both sensory and social impairments in autism spectrum disorder (ASD). Little is known regarding the brain mechanisms that guide multisensory integration, and how such neural activity might be affected by autistic-like symptoms in the general population. In this study, 72 healthy young adults performed an audiovisual speech synchrony judgment (SJ) task during fMRI scanning. We aimed to investigate the SJ-related brain activations and connectivity, with a focus on the AI. Compared with synchronous speech, asynchrony perception triggered stronger activations in the bilateral AI, and other frontal-cingulate-parietal regions. In contrast, synchronous perception resulted in greater involvement of the primary auditory and visual areas, indicating multisensory validation and fusion. Moreover, the AI demonstrated a stronger connection with the anterior cingulate gyrus (ACC) in the audiovisual asynchronous (vs. synchronous) condition. To facilitate asynchrony detection, the AI may integrate auditory and visual speech stimuli, and generate a control signal to the ACC that further supports conflict-resolving and response selection. Correlation analysis, however, suggested that audiovisual synchrony perception and its related AI activation and connectivity did not significantly vary with different levels of autistic traits. These findings provide novel evidence for the neural mechanisms underlying multisensory temporal processing in healthy people. Future research should examine whether such findings would be extended to ASD patients.

Audiovisual temporal processing in adult patients with first-episode schizophrenia and high-functioning autism

Schizophrenia and autism spectrum disorder (ASD) are both neurodevelopmental disorders with altered sensory processing. Widened temporal binding window (TBW) signifies reduced sensitivity to detect stimulus asynchrony, and may be a shared feature in schizophrenia and ASD. Few studies directly compared audiovisual temporal processing ability in the two disorders. We recruited 43 adult patients with first-episode schizophrenia (FES), 35 average intelligent and verbally-fluent adult patients with high-functioning ASD and 48 controls. We employed two unisensory Temporal Order Judgement (TOJ) tasks within visual or auditory modalities, and two audiovisual Simultaneity Judgement (SJ) tasks with flash-beeps and videos of syllable utterance as stimuli. Participants with FES exhibited widened TBW affecting both speech and non-speech processing, which were not attributable to altered unisensory sensory acuity because they had normal visual and auditory TOJ thresholds. However, adults with ASD exhibited intact unisensory and audiovisual temporal processing. Lower non-verbal IQ was correlated with larger TBW width across the three groups. Taking our findings with earlier evidence in chronic samples, widened TBW is associated with schizophrenia regardless illness stage. The altered audiovisual temporal processing in ASD may ameliorate after reaching adulthood.

Audiovisual synchrony detection for fluent speech in early childhood: An eye-tracking study

During childhood, the ability to detect audiovisual synchrony gradually sharpens for simple stimuli such as flashbeeps and single syllables. However, little is known about how children perceive synchrony for natural and continuous speech. This study investigated young children's gaze patterns while they were watching movies of two identical speakers telling stories side by side. Only one speaker's lip movements matched the voices and the other one either led or lagged behind the soundtrack by 600 ms. Children aged 3-6 years (n = 94, 52.13% males) showed an overall preference for the synchronous speaker, with no age-related changes in synchrony-detection sensitivity as indicated by similar gaze patterns across ages. However, viewing time to the synchronous speech was significantly longer in the auditory-leading (AL) condition compared with that in the visual-leading (VL) condition, suggesting asymmetric sensitivities for AL versus VL asynchrony have already been established in early childhood. When further examining gaze patterns on dynamic faces, we found that more attention focused on the mouth region was an adaptive strategy to read visual speech signals and thus associated with increased viewing time of the synchronous videos. Attention to detail, one dimension of autistic traits featured by local processing, has been found to be correlated with worse performances in speech synchrony processing. These findings extended previous research by showing the development of speech synchrony perception in young children, and may have implications for clinical populations (e.g., autism) with impaired multisensory integration.

Rhythm and timing as vulnerabilities in neurodevelopmental disorders

Millions of children are impacted by neurodevelopmental disorders (NDDs), which unfold early in life, have varying genetic etiologies and can involve a variety of specific or generalized impairments in social, cognitive and motor functioning requiring potentially lifelong specialized supports. While specific disorders vary in their domain of primary deficit (e.g. autism spectrum disorder (social), attention-deficit/hyperactivity disorder (attention), developmental coordination disorder (motor) and developmental language disorder (language)), comorbidities between NDDs are common. Intriguingly, many NDDs are associated with difficulties in skills related to rhythm, timing and synchrony though specific profiles of rhythm/timing impairments vary across disorders. Impairments in rhythm/timing may instantiate vulnerabilities for a variety of NDDs and may contribute to both the primary symptoms of each disorder as well as the high levels of comorbidities across disorders. Drawing upon genetic, neural, behavioural and interpersonal constructs across disorders, we consider how disrupted rhythm and timing skills early in life may contribute to atypical developmental cascades that involve overlapping symptoms within the context of a disorder's primary deficits. Consideration of the developmental context, as well as common and unique aspects of the phenotypes of different NDDs, will inform experimental designs to test this hypothesis including via potential mechanistic intervention approaches. This article is part of the theme issue 'Synchrony and rhythm interaction: from the brain to behavioural ecology'.

Atypical gaze patterns to facial feature areas in autism spectrum disorders reveal age and culture effects: A meta-analysis of eye-tracking studies

Children and adults with autism spectrum disorder (ASD) often present with atypical gaze patterns to others' faces, a finding substantiated throughout the literature. Yet, a quantification of atypical gaze patterns to different facial regions (e.g., eyes versus mouth) in ASD remains controversial. Also few study has investigated how age and culture impacted the pattern of gaze abnormalities in ASD. This research therefore conducted a meta-analysis of eye-tracking studies to evaluate age and culture effect on atypical gaze patterns of face processing in ASD. A total of 75 articles (91 studies) and 4209 individuals (ASD: 2027; controls: 2182) across all age ranges (i.e., childhood through to adulthood) from both Eastern and Western cultures were included in this meta-analysis. Individuals with ASD yielded shorter fixation durations to the eyes than individuals without ASD. Group differences in the time spent fixating on the eyes were not modulated by age, but affected by culture. Effect size in the eastern culture was larger than that in the western culture. In contrast, group differences on time spent looking at the mouth were not significant, but changed with age and modulated by culture. Relative to the neurotypical controls, Western individuals with ASD spent more time looking at the mouth from school age, whereas Eastern individuals with ASD did not gaze longer on mouth until adulthood. These results add to the body of evidence supporting atypical gaze behaviors to eyes in ASD and provide new insights into a potential mouth compensation strategy that develops with age in ASD. LAY SUMMARY: Individuals with autism spectrum disorder (ASD) often show atypical gaze patterns when looking at others' faces compared to neurotypical individuals. This paper examines the role of age and culture on pattern of gaze abnormalities in individuals with ASD. Results show that reduction of gaze on eyes in ASD is stable across all ages and cultures, while increase of gaze on mouth emerges as individuals with ASD get older. The findings provide a developmental insight to the gaze patterns on the autism spectrum across culture.

Temporal Synchrony in Autism: a Systematic Review

Temporal synchrony is the alignment of processes in time within or across individuals in social interaction and is observed and studied in various domains using wide-ranging paradigms. Evidence suggesting reduced temporal synchrony in autism (e.g. compared to neurotypicals) has hitherto not been reviewed. To systematically review the magnitude and generalisability of the difference across different tasks and contexts, EBSCO, OVID, Web of Science, and Scopus databases were searched. Thirty-two studies were identified that met our inclusion criteria in audio-visual, audio-motor, visuo-tactile, visuo-motor, social motor, and conversational synchrony domains. Additionally, two intervention studies were included. The findings suggest that autistic participants showed reduced synchrony tendencies in every category of temporal synchrony reviewed. Implications, methodological weaknesses, and evidence gaps are discussed.

Social attention as a cross-cultural transdiagnostic neurodevelopmental risk marker

The primary objectives of this study were to evaluate the structure and age-related stability of social attention in English and Arabic-speaking youth and to compare social attention between children with autism spectrum disorder (ASD), other developmental disabilities (DD), and typically-developing controls. Eye-tracking data were collected from US (N = 270) and Qatari (N = 242) youth ages 1-17, including children evaluated for possible ASD. Participants viewed 44 stimuli from seven social paradigms. Fixation was computed for areas of interest within each stimulus. Latent variable models examined the structure of social attention. Generalized estimating equation models examined the effect of age, sex, culture, and diagnostic group on social attention. The best-fitting model included a general social attention factor and six specific factors. Cultural differences in social attention were minimal and social attention was stable across age (r = 0.03), but females showed significantly greater social attention than males (d = 0.28). Social attention was weaker in DD (d = -0.17) and lowest in ASD (d = -0.38) relative to controls. Differences were of sufficient magnitude across areas-of-interest to reliably differentiate DD from controls (AUC = 0.80) and ASD-only from all other cases (AUC = 0.76). A social attention dimension that represents an early-life preference for socially salient information was identified. This preference was cross-culturally consistent and stable across development but stronger in females and weaker in DD, especially ASD. Given rapid and easy-to-collect remote eye tracking administration, social attention measurement may be useful for developmental monitoring. Acquisition of population norms, analogous to height/weight/head circumference, might enhance early screening and tracking of neurodevelopment. LAY SUMMARY: This research found that social attention is a single dimension of behavior that represents a strong preference for social stimuli, is consistent across cultures, stable across age, and stronger in females. Children with developmental disabilities had lower levels of social attention than neurotypical children and children with autism spectrum disorder had the lowest levels of social attention.

Reduced multisensory facilitation exists at different periods of development in autism

Atypical sensory processing is now recognised as a key component of an autism diagnosis. The integration of multiple sensory inputs (multisensory integration (MSI)) is thought to be idiosyncratic in autistic individuals and may have cascading effects on the development of higher-level skills such as social communication. Multisensory facilitation was assessed using a target detection paradigm in 45 autistic and 111 neurotypical individuals, matched on age and IQ. Target stimuli were: auditory (A; 3500 Hz tone), visual (V; white disk 'flash') or audiovisual (AV; simultaneous tone and flash), and were presented on a dark background in a randomized order with varying stimulus onset delays. Reaction time (RT) was recorded via button press. In order to assess possible developmental effects, participants were divided into younger (age 14 or younger) and older (age 15 and older) groups. Redundancy gain (RG) was significantly greater in neurotypical, compared to autistic individuals. No significant effect of age or interaction was found. Race model analysis was used to compute a bound value that represented the facilitation effect provided by MSI. Our results revealed that MSI facilitation occurred (violation of the race model) in neurotypical individuals, with more efficient MSI in older participants. In both the younger and older autistic groups, we found reduced MSI facilitation (no or limited violation of the race model). Autistic participants showed reduced multisensory facilitation compared to neurotypical participants in a simple target detection task, void of social context. This remained consistent across age. Our results support evidence that autistic individuals may not integrate low-level, non-social information in a typical fashion, adding to the growing discussion around the influential effect that basic perceptual atypicalities may have on the development of higher-level, core aspects of autism.

Stability of Variables Derived From Measures of Multisensory Function in Children With Autism Spectrum Disorder

Children with autism spectrum disorder (ASD) display differences in multisensory function as quantified by several different measures. This study estimated the stability of variables derived from commonly used measures of multisensory function in school-aged children with ASD. Participants completed: a simultaneity judgment task for audiovisual speech, tasks designed to elicit the McGurk effect, listening-in-noise tasks, electroencephalographic recordings, and eye-tracking tasks. Results indicate the stability of indices derived from tasks tapping multisensory processing is variable. These findings have important implications for measurement in future research. Averaging scores across repeated observations will often be required to obtain acceptably stable estimates and, thus, to increase the likelihood of detecting effects of interest, as it relates to multisensory processing in children with ASD.

Do Animals Engage Greater Social Attention in Autism? An Eye Tracking Analysis

BACKGROUND

Visual atypicalities in autism spectrum disorder (ASD) are a well documented phenomenon, beginning as early as 2-6 months of age and manifesting in a significantly decreased attention to the eyes, direct gaze and socially salient information. Early emerging neurobiological deficits in perceiving social stimuli as rewarding or its active avoidance due to the anxiety it entails have been widely purported as potential reasons for this atypicality. Parallel research evidence also points to the significant benefits of animal presence for reducing social anxiety and enhancing social interaction in children with autism. While atypicality in social attention in ASD has been widely substantiated, whether this atypicality persists equally across species types or is confined to humans has not been a key focus of research insofar.

METHODS

We attempted a comprehensive examination of the differences in visual attention to static images of human and animal faces (40 images; 20 human faces and 20 animal faces) among children with ASD using an eye tracking paradigm. 44 children (ASD n = 21; TD n = 23) participated in the study (10,362 valid observations) across five regions of interest (left eye, right eye, eye region, face and screen).

RESULTS

Results obtained revealed significantly greater social attention across human and animal stimuli in typical controls when compared to children with ASD. However in children with ASD, a significantly greater attention allocation was seen to animal faces and eye region and lesser attention to the animal mouth when compared to human faces, indicative of a clear attentional preference to socially salient regions of animal stimuli. The positive attentional bias toward animals was also seen in terms of a significantly greater visual attention to direct gaze in animal images.

CONCLUSION

Our results suggest the possibility that atypicalities in social attention in ASD may not be uniform across species. It adds to the current neural and biomarker evidence base of the potentially greater social reward processing and lesser social anxiety underlying animal stimuli as compared to human stimuli in children with ASD.

Reducing facial dynamics' speed during speech enhances attention to mouth in children with autism spectrum disorder: An eye-tracking study

Facial movements of others during verbal and social interaction are often too rapid to be faced and/or processed in time by numerous children and adults with autism spectrum disorder (ASD), which could contribute to their face-to-face interaction peculiarities. We wish here to measure the effect of reducing the speed of one's facial dynamics on the visual exploration of the face by children with ASD. Twenty-three children with ASD and 29 typically-developing control children matched for chronological age passively viewed a video of a speaker telling a story at various velocities, i.e., a real-time speed and two slowed-down speeds. The visual scene was divided into four areas of interest (AOI): face, mouth, eyes, and outside the face. With an eye-tracking system, we measured the percentage of total fixation duration per AOI and the number and mean duration of the visual fixations made on each AOI. In children with ASD, the mean duration of visual fixations on the mouth region, which correlated with their verbal level, increased at slowed-down velocity compared with the real-time one, a finding which parallels a result also found in the control children. These findings strengthen the therapeutic potential of slowness for enhancing verbal and language abilities in children with ASD.

Audiovisual temporal integration: Cognitive processing, neural mechanisms, developmental trajectory and potential interventions

To integrate auditory and visual signals into a unified percept, the paired stimuli must co-occur within a limited time window known as the Temporal Binding Window (TBW). The width of the TBW, a proxy of audiovisual temporal integration ability, has been found to be correlated with higher-order cognitive and social functions. A comprehensive review of studies investigating audiovisual TBW reveals several findings: (1) a wide range of top-down processes and bottom-up features can modulate the width of the TBW, facilitating adaptation to the changing and multisensory external environment; (2) a large-scale brain network works in coordination to ensure successful detection of audiovisual (a)synchrony; (3) developmentally, audiovisual TBW follows a U-shaped pattern across the lifespan, with a protracted developmental course into late adolescence and rebounding in size again in late life; (4) an enlarged TBW is characteristic of a number of neurodevelopmental disorders; and (5) the TBW is highly flexible via perceptual and musical training. Interventions targeting the TBW may be able to improve multisensory function and ameliorate social communicative symptoms in clinical populations.

Time perception and autistic spectrum condition: A systematic review

Problems with timing and time perception have been suggested as key characteristics of autism spectrum condition (ASC). Studies and personal accounts from clinicians, parents, caregivers, and self‐reports from autistic people themselves often refer to problems with time. Although a number of empirical studies have examined aspects relating to time in autistic individuals, there remains no clear consensus on whether or how timing mechanisms may be affected in autism. A key reason for this lack of clarity is the wide range of timing processes that exist and subsequently the wide range of methodologies, research paradigms, and samples that time‐based studies have used with autism populations. In order to summarize and organize the available literature on this issue, a systematic review was conducted. Five electronic databases were consulted. From an initial 597 records (after duplicates were removed), 45 papers were selected and reviewed. The studies are reviewed within different sections based on the different types of timing ability that have been explored in the neurotypical (NT) population: time sensitivity, interval timing, and higher‐order time perception. Within each section cognitive models, methodologies, possible clinical implications, and research results are discussed. The results show different consistency across studies between the three types of timing ability. The highest consistency of results showing atypical time perception abilities is found in high‐level time perception studies. It remains unclear if autism is characterized by a fundamental time perception impairment. Suggestions for future research are discussed. Autism Res 2019, 12: 1440–1462. © 2019 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

This systematic review examines the different types of timing and time perception behavior that have been investigated in autism. Overall, there are a number of studies that show differences between autistic and non‐autistic individuals, but some studies do not find such differences. Group differences are more consistent across studies using complex tasks rather than simpler more fundamental timing tasks. We suggest that experiments across a range of timing tasks would be fruitful to address gaps in our knowledge.

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.

Specific Patterns of Emotion Recognition from Faces in Children with ASD: Results of a Cross-Modal Matching Paradigm

Children with ASD show emotion recognition difficulties, as part of their social communication deficits. We examined facial emotion recognition (FER) in intellectually disabled children with ASD and in younger typically developing (TD) controls, matched on mental age. Our emotion-matching paradigm employed three different modalities: facial, vocal and verbal. Results confirmed overall FER deficits in ASD. Compared to the TD group, children with ASD had the poorest performance in recognizing surprise and anger in comparison to happiness and sadness, and struggled with face-face matching, compared to voice-face and word-face combinations. Performance in the voice-face cross-modal recognition task was related to adaptive communication. These findings highlight the specific face processing deficit, and the relative merit of cross-modal integration in children with ASD.

Free viewing of talking faces reveals mouth and eye preferring regions of the human superior temporal sulcus

During face-to-face communication, the mouth of the talker is informative about speech content, while the eyes of the talker convey other information, such as gaze location. Viewers most often fixate either the mouth or the eyes of the talker's face, presumably allowing them to sample these different sources of information. To study the neural correlates of this process, healthy humans freely viewed talking faces while brain activity was measured with BOLD fMRI and eye movements were recorded with a video-based eye tracker. Post hoc trial sorting was used to divide the data into trials in which participants fixated the mouth of the talker and trials in which they fixated the eyes. Although the audiovisual stimulus was identical, the two trials types evoked differing responses in subregions of the posterior superior temporal sulcus (pSTS). The anterior pSTS preferred trials in which participants fixated the mouth of the talker while the posterior pSTS preferred fixations on the eye of the talker. A second fMRI experiment demonstrated that anterior pSTS responded more strongly to auditory and audiovisual speech than posterior pSTS eye-preferring regions. These results provide evidence for functional specialization within the pSTS under more realistic viewing and stimulus conditions than in previous neuroimaging studies.

Audiovisual multisensory integration in individuals with autism spectrum disorder: A systematic review and meta-analysis

An ever-growing literature has aimed to determine how individuals with autism spectrum disorder (ASD) differ from their typically developing (TD) peers on measures of multisensory integration (MSI) and to ascertain the degree to which differences in MSI are associated with the broad range of symptoms associated with ASD. Findings, however, have been highly variable across the studies carried out to date. The present work systematically reviews and quantitatively synthesizes the large literature on audiovisual MSI in individuals with ASD to evaluate the cumulative evidence for (a) group differences between individuals with ASD and TD peers, (b) correlations between MSI and autism symptoms in individuals with ASD and (c) study level factors that may moderate findings (i.e., explain differential effects) observed across studies. To identify eligible studies, a comprehensive search strategy was employed using the ProQuest search engine, PubMed database, forwards and backwards citation searches, direct author contact, and hand-searching of select conference proceedings. A significant between-group difference in MSI was evident in the literature, with individuals with ASD demonstrating worse audiovisual integration on average across studies compared to TD controls. This effect was moderated by mean participant age, such that between-group differences were more pronounced in younger samples. The mean correlation between MSI and autism and related symptomatology was also significant, indicating that increased audiovisual integration in individuals with ASD is associated with better language/communication abilities and/or reduced autism symptom severity in the extant literature. This effect was moderated by whether the stimuli were linguistic versus non-linguistic in nature, such that correlation magnitudes tended to be significantly greater when linguistic stimuli were utilized in the measure of MSI. Limitations and future directions for primary and meta-analytic research are discussed.

Cross-situational and ostensive word learning in children with and without autism spectrum disorder

Numerous experimental studies have shown that infants and children can discover word meanings by using co-occurrences between labels and objects across individually ambiguous contexts-a phenomenon known as cross-situational learning. Like typically developing children, high-functioning school aged children with autism spectrum disorder (ASD) are capable of cross-situational learning. However, it is not yet clear whether cross-situational learning is similarly available to children with ASD who are younger and show a broader range of language and cognitive abilities. Using eye-tracking methodology, the current study provided the first evidence that preschool and early school-aged children with ASD can rely on cross-situational statistics to learn new words. In fact, children with ASD learned as well as typically developing children with similar vocabulary knowledge. In both groups, the children with the highest cross-situational learning accuracy were those who showed the best familiar word processing skills. Surprisingly, children in both groups learned words equally well in the cross-situational task and an ostensive word-learning task, which presented only a single label-object pairing at a time. In combination, these results point to similarities in the word learning abilities available to typically developing children and children with ASD.

Sensitivity to audio-visual synchrony and its relation to language abilities in children with and without ASD

Autism Spectrum Disorder (ASD) is often accompanied by deficits in speech and language processing. Speech processing relies heavily on the integration of auditory and visual information, and it has been suggested that the ability to detect correspondence between auditory and visual signals helps to lay the foundation for successful language development. The goal of the present study was to examine whether young children with ASD show reduced sensitivity to temporal asynchronies in a speech processing task when compared to typically developing controls, and to examine how this sensitivity might relate to language proficiency. Using automated eye tracking methods, we found that children with ASD failed to demonstrate sensitivity to asynchronies of 0.3s, 0.6s, or 1.0s between a video of a woman speaking and the corresponding audio track. In contrast, typically developing children who were language-matched to the ASD group, were sensitive to both 0.6s and 1.0s asynchronies. We also demonstrated that individual differences in sensitivity to audiovisual asynchronies and individual differences in orientation to relevant facial features were both correlated with scores on a standardized measure of language abilities. Results are discussed in the context of attention to visual language and audio-visual processing as potential precursors to language impairment in ASD. Autism Res 2018, 11: 645-653. © 2018 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Speech processing relies heavily on the integration of auditory and visual information, and it has been suggested that the ability to detect correspondence between auditory and visual signals helps to lay the foundation for successful language development. The goal of the present study was to explore whether children with ASD process audio-visual synchrony in ways comparable to their typically developing peers, and the relationship between preference for synchrony and language ability. Results showed that there are differences in attention to audiovisual synchrony between typically developing children and children with ASD. Preference for synchrony was related to the language abilities of children across groups.

A Computational Analysis of Neural Mechanisms Underlying the Maturation of Multisensory Speech Integration in Neurotypical Children and Those on the Autism Spectrum

Failure to appropriately develop multisensory integration (MSI) of audiovisual speech may affect a child's ability to attain optimal communication. Studies have shown protracted development of MSI into late-childhood and identified deficits in MSI in children with an autism spectrum disorder (ASD). Currently, the neural basis of acquisition of this ability is not well understood. Here, we developed a computational model informed by neurophysiology to analyze possible mechanisms underlying MSI maturation, and its delayed development in ASD. The model posits that strengthening of feedforward and cross-sensory connections, responsible for the alignment of auditory and visual speech sound representations in posterior superior temporal gyrus/sulcus, can explain behavioral data on the acquisition of MSI. This was simulated by a training phase during which the network was exposed to unisensory and multisensory stimuli, and projections were crafted by Hebbian rules of potentiation and depression. In its mature architecture, the network also reproduced the well-known multisensory McGurk speech effect. Deficits in audiovisual speech perception in ASD were well accounted for by fewer multisensory exposures, compatible with a lack of attention, but not by reduced synaptic connectivity or synaptic plasticity.

Increases in the autistic trait of attention to detail are associated with decreased multisensory temporal adaptation

Recent empirical evidence suggests that autistic individuals perceive the world differently than their typically-developed peers. One theoretical account, the predictive coding hypothesis, posits that autistic individuals show a decreased reliance on previous perceptual experiences, which may relate to autism symptomatology. We tested this through a well-characterized, audiovisual statistical-learning paradigm in which typically-developed participants were first adapted to consistent temporal relationships between audiovisual stimulus pairs (audio-leading, synchronous, visual-leading) and then performed a simultaneity judgement task with audiovisual stimulus pairs varying in temporal offset from auditory-leading to visual-leading. Following exposure to the visual-leading adaptation phase, participants' perception of synchrony was biased towards visual-leading presentations, reflecting the statistical regularities of their previously experienced environment. Importantly, the strength of adaptation was significantly related to the level of autistic traits that the participant exhibited, measured by the Autism Quotient (AQ). This was specific to the Attention to Detail subscale of the AQ that assesses the perceptual propensity to focus on fine-grain aspects of sensory input at the expense of more integrative perceptions. More severe Attention to Detail was related to weaker adaptation. These results support the predictive coding framework, and suggest that changes in sensory perception commonly reported in autism may contribute to autistic symptomatology.

The cascading influence of multisensory processing on speech perception in autism

It has been recently theorized that atypical sensory processing in autism relates to difficulties in social communication. Through a series of tasks concurrently assessing multisensory temporal processes, multisensory integration and speech perception in 76 children with and without autism, we provide the first behavioral evidence of such a link. Temporal processing abilities in children with autism contributed to impairments in speech perception. This relationship was significantly mediated by their abilities to integrate social information across auditory and visual modalities. These data describe the cascading impact of sensory abilities in autism, whereby temporal processing impacts multisensory information of social information, which, in turn, contributes to deficits in speech perception. These relationships were found to be specific to autism, specific to multisensory but not unisensory integration, and specific to the processing of social information.

Links between temporal acuity and multisensory integration across life span

The temporal relationship between individual pieces of information from the different sensory modalities is one of the stronger cues to integrate such information into a unified perceptual gestalt, conveying numerous perceptual and behavioral advantages. Temporal acuity, however, varies greatly over the life span. It has previously been hypothesized that changes in temporal acuity in both development and healthy aging may thus play a key role in integrative abilities. This study tested the temporal acuity of 138 individuals ranging in age from 5 to 80. Temporal acuity and multisensory integration abilities were tested both within and across modalities (audition and vision) with simultaneity judgment and temporal order judgment tasks. We observed that temporal acuity, both within and across modalities, improved throughout development into adulthood and subsequently declined with healthy aging, as did the ability to integrate multisensory speech information. Of importance, throughout development, temporal acuity of simple stimuli (i.e., flashes and beeps) predicted individuals' abilities to integrate more complex speech information. However, in the aging population, although temporal acuity declined with healthy aging and was accompanied by declines in integrative abilities, temporal acuity was not able to predict integration at the individual level. Together, these results suggest that the impact of temporal acuity on multisensory integration varies throughout the life span. Although the maturation of temporal acuity drives the rise of multisensory integrative abilities during development, it is unable to account for changes in integrative abilities in healthy aging. The differential relationships between age, temporal acuity, and multisensory integration suggest an important role for experience in these processes. (PsycINFO Database Record

Electroencephalogram Coherence Patterns in Autism: An Updated Review

Electrophysiologic studies suggest that autism spectrum disorder is characterized by aberrant anatomic and functional neural circuitry. During normal brain development, pruning and synaptogenesis facilitate ongoing changes in both short- and long-range neural wiring. In developmental disorders such as autism, this process may be perturbed and lead to abnormal neural connectivity. Careful analysis of electrophysiologic connectivity patterns using EEG coherence may provide a way to probe the resulting differences in neurological function between people with and without autism. There is general consensus that electroencephalogram coherence patterns differ between individuals with and without autism spectrum disorders; however, the exact nature of the differences and their clinical significance remain unclear. Here we review recent literature comparing electroencephalogram coherence patterns between patients with autism spectrum disorders or at high risk for autism and their nonautistic or low-risk for autism peers.

Basic and complex emotion recognition in children with autism: cross-cultural findings

BACKGROUND

Children with autism spectrum conditions (ASC) have emotion recognition deficits when tested in different expression modalities (face, voice, body). However, these findings usually focus on basic emotions, using one or two expression modalities. In addition, cultural similarities and differences in emotion recognition patterns in children with ASC have not been explored before. The current study examined the similarities and differences in the recognition of basic and complex emotions by children with ASC and typically developing (TD) controls across three cultures: Israel, Britain, and Sweden.

METHODS

Fifty-five children with high-functioning ASC, aged 5-9, were compared to 58 TD children. On each site, groups were matched on age, sex, and IQ. Children were tested using four tasks, examining recognition of basic and complex emotions from voice recordings, videos of facial and bodily expressions, and emotional video scenarios including all modalities in context.

RESULTS

Compared to their TD peers, children with ASC showed emotion recognition deficits in both basic and complex emotions on all three modalities and their integration in context. Complex emotions were harder to recognize, compared to basic emotions for the entire sample. Cross-cultural agreement was found for all major findings, with minor deviations on the face and body tasks.

CONCLUSIONS

Our findings highlight the multimodal nature of ER deficits in ASC, which exist for basic as well as complex emotions and are relatively stable cross-culturally. Cross-cultural research has the potential to reveal both autism-specific universal deficits and the role that specific cultures play in the way empathy operates in different countries.

The influence of presentation modality on the social comprehension of naturalistic scenes in adults with autism spectrum disorder

The comprehension of dynamically unfolding social situations is made possible by the seamless integration of multimodal information merged with rich intuitions about the thoughts and behaviors of others. We examined how high-functioning adults with autism spectrum disorder and neurotypical controls made a complex social judgment (i.e. rating the social awkwardness of scenes from a television sitcom) across three conditions that manipulated presentation modality-visual alone, transcribed text alone, or visual and auditory together. The autism spectrum disorder and control groups collectively assigned similar mean awkwardness ratings to individual scenes. However, individual participants with autism spectrum disorder tended to respond more idiosyncratically than controls, assigning ratings that were less correlated with the ratings of the other participants in the sample. We found no evidence that this group difference was isolated to any specific presentation modality. In a comparison condition, we found no group differences when participants instead rated the happiness of characters (a more basic social judgment) in full audiovisual format. Thus, although we observed differences in the manner with which high-functioning adults with autism spectrum disorder make social judgments compared to controls, these group differences may be dependent on the social dimension being judged, rather than the specific modality of presentation.

Behavioral, perceptual, and neural alterations in sensory and multisensory function in autism spectrum disorder

Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what is currently known about sensory processing in ASD, how sensory function fits within contemporary models of ASD, and what is understood about the differences in the underlying neural processing of sensory and social communication observed between individuals with and without ASD. In addition to highlighting the sensory features associated with ASD, we also emphasize the importance of multisensory processing in building perceptual and cognitive representations, and how deficits in multisensory integration may also be a core characteristic of ASD.

Keeping time in the brain: Autism spectrum disorder and audiovisual temporal processing

A growing area of interest and relevance in the study of autism spectrum disorder (ASD) focuses on the relationship between multisensory temporal function and the behavioral, perceptual, and cognitive impairments observed in ASD. Atypical sensory processing is becoming increasingly recognized as a core component of autism, with evidence of atypical processing across a number of sensory modalities. These deviations from typical processing underscore the value of interpreting ASD within a multisensory framework. Furthermore, converging evidence illustrates that these differences in audiovisual processing may be specifically related to temporal processing. This review seeks to bridge the connection between temporal processing and audiovisual perception, and to elaborate on emerging data showing differences in audiovisual temporal function in autism. We also discuss the consequence of such changes, the specific impact on the processing of different classes of audiovisual stimuli (e.g. speech vs. nonspeech, etc.), and the presumptive brain processes and networks underlying audiovisual temporal integration. Finally, possible downstream behavioral implications, and possible remediation strategies are outlined. Autism Res 2016, 9: 720-738. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.