Processing In Autism Spectrum Disorder Research Articles

Auditory processing in autism spectrum disorder: Mismatch negativity deficits.

Automatic detection of deviant sounds in the environment, such as upcoming traffic, is often affected in children with autism spectrum disorders (ASD). Mismatch negativity (MMN) is a way to quantify automatic deviancy detection, using electroencephalography. In this study, auditory MMN was assessed in 35 children with ASD and 38 matched control children, revealing significantly reduced MMN in the ASD group. This may indicate that children with ASD are less able to automatically detect environmentally deviant stimuli.

Neural networks underlying language and social cognition during self-other processing in Autism spectrum disorders.

The social communication impairments defining autism spectrum disorders (ASD) may be built upon core deficits in perspective-taking, language processing, and self-other representation. Self-referential processing entails the ability to incorporate self-awareness, self-judgment, and self-memory in information processing. Very few studies have examined the neural bases of integrating self-other representation and semantic processing in individuals with ASD. The main objective of this functional MRI study is to examine the role of language and social brain networks in self-other processing in young adults with ASD. Nineteen high-functioning male adults with ASD and 19 age-sex-and-IQ-matched typically developing (TD) control participants made "yes" or "no" judgments of whether an adjective, presented visually, described them (self) or their favorite teacher (other). Both ASD and TD participants showed significantly increased activity in the medial prefrontal cortex (MPFC) during self and other processing relative to letter search. Analyses of group differences revealed significantly reduced activity in left inferior frontal gyrus (LIFG), and left inferior parietal lobule (LIPL) in ASD participants, relative to TD controls. ASD participants also showed significantly weaker functional connectivity of the anterior cingulate cortex (ACC) with several brain areas while processing self-related words. The LIFG and IPL are important regions functionally at the intersection of language and social roles; reduced recruitment of these regions in ASD participants may suggest poor level of semantic and social processing. In addition, poor connectivity of the ACC may suggest the difficulty in meeting the linguistic and social demands of this task in ASD. Overall, this study provides new evidence of the altered recruitment of the neural networks underlying language and social cognition in ASD.

Global and local visual processing in autism: An objective assessment approach.

We examined global and local visual processing in autism spectrum disorder (ASD) via a match-to-sample task using Kanizsa illusory contours (KIC). School-aged children with ASD (n = 28) and age-matched typically developing controls (n = 22; 7-13 years) performed a sequential match-to-sample between a solid shape (sample) and two illusory alternatives. We tracked eye gaze and behavioral performance in two task conditions: one with and one without local interference from background noise elements. While analyses revealed lower accuracy and longer reaction time in ASD in the condition with local interference only, eye tracking robustly captured ASD-related global atypicalities across both conditions. Specifically, relative to controls, children with ASD showed decreased fixations to KIC centers, indicating reduced global perception. Notably, they did not differ from controls in regard to fixations to local elements or touch response location. These results indicate impaired global perception in the absence of heightened local processing in ASD. They also underscore the utility of eye-tracking measures as objective indices of global/local visual processing strategies in ASD. Autism Res 2017, 10: 1392-1404. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Face processing in autism spectrum disorder

BackgroundAutism spectrum disorder (ASD) is a lifelong neurodevelopmental disorder that is characterized by impaired social and communicative abilities as well as restricted, repetitive, stereotyped pattern of behaviors, interests, and activities. Significant difficulties in social interactions in autistics are manifested by impairment in eye-to-eye contact, social reciprocity, and response to emotional cues.ObjectiveHighlighting the neurological basis of normal face processing and its abnormalities in ASD with percussions on the management plan of autistic children.SummaryHuman face processing that was proved to be compromised in autistic individuals is pivotal for proper social interactions. Such simple spontaneous perceptual task in normal children is carried out by face processing areas of the brain; fusiform gyrus, superior temporal sulcus, and amygdala. Behavioral, electrophysiological, and neuroimaging studies showed evidences of dysfunction of such areas in autistics who often focus on face periphery and cannot interpret that it tells something about a person's state of mind. Very early targeted intervention can stimulate face processing areas of the brain during the early developmental phases of social brain circuitry which in turn will help autistics to pay attention to faces and learn to understand emotional expressions.ConclusionEventually, prevention or at least significant amelioration of severity and symptomatology spectrum of autism might be possible.Disclosure of interestThe author have not supplied his declaration of competing interest.

Reduced specificity in emotion judgment in people with autism spectrum disorder

There is a conflicting literature on facial emotion processing in autism spectrum disorder (ASD): both typical and atypical performance have been reported, and inconsistencies in the literature may stem from different processes examined (emotion judgment, face perception, fixations) as well as differences in participant populations. Here we conducted a detailed investigation of the ability to discriminate graded emotions shown in morphs of fear-happy faces, in a well-characterized high-functioning sample of participants with ASD and matched controls. Signal detection approaches were used in the analyses, and concurrent high-resolution eye-tracking was collected. Although people with ASD had typical thresholds for categorical fear and confidence judgments, their psychometric specificity to detect emotions across the entire range of intensities was reduced. However, fixation patterns onto the stimuli were typical and could not account for the reduced specificity of emotion judgment. Together, our results argue for a subtle and specific deficit in emotion perception in ASD that, from a signal detection perspective, is best understood as a reduced specificity due to increased noise in central processing of the face stimuli.

Highlights on Aberrant Face Processing in Autism Spectrum Disorder and its Percussions on Management of Autistics

Highlighting the neurological basis of normal face processing and its abnormalities in ASD seems crucial because of its percussions on symptomatology and the management plan of autistic children. Human face processing that has been proven to be compromised in many autistic individuals is pivotal for proper social interactions. Such spontaneous perceptual task in normal children is carried out by face processing areas of the brain as fusiform gyrus, superior temporal sulcus, and amygdala. Behavioral, electrophysiological, and neuroimaging studies showed evidences of dysfunction of such areas in many autistics who often focus on face periphery and cannot interpret that it tells something about a person’s state of mind. Very early targeted intervention can stimulate face processing areas of the brain during the early developmental phases of social brain circuitry which in turn will help autistics to pay attention to faces and learn how to understand emotional expressions. Eventually, prevention or at least significant amelioration of both the spectrum and severity of autistic symptomatology might be possible.

Benchmark eye movement effects during natural reading in autism spectrum disorder.

In 2 experiments, eye tracking methodology was used to assess on-line lexical, syntactic and semantic processing in autism spectrum disorder (ASD). In Experiment 1, lexical identification was examined by manipulating the frequency of target words. Both typically developed (TD) and ASD readers showed normal frequency effects, suggesting that the processes TD and ASD readers engage in to identify words are comparable. In Experiment 2, syntactic parsing and semantic interpretation requiring the on-line use of world knowledge were examined, by having participants read garden path sentences containing an ambiguous prepositional phrase. Both groups showed normal garden path effects when reading low-attached sentences and the time course of reading disruption was comparable between groups. This suggests that not only do ASD readers hold similar syntactic preferences to TD readers, but also that they use world knowledge on-line during reading. Together, these experiments demonstrate that the initial construction of sentence interpretation appears to be intact in ASD. However, the finding that ASD readers skip target words less often in Experiment 2, and take longer to read sentences during second pass for both experiments, suggests that they adopt a more cautious reading strategy and take longer to evaluate their sentence interpretation prior to making a manual response. (PsycINFO Database Record

Unusual auditory/speech processing in autism spectrum disorder revealed by verbal transformation effects

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by an impaired ability to communicate and restricted and repetitive patterns of behavior. Sensory abnormality, a trait included in restricted patterns of behavior, is often observed in individuals with ASD. This study used an auditory illusion called “verbal transformation (VT)” to examine abnormal auditory/speech processing in ASD. In VT, a series of subjective perceptual changes occurs when subjects listen to a repeating word without a pause. The characteristic of VT is that, physically, the stimulus is the same repeated word but the perceptual change differs for each person. In this point, VT could be useful for demonstrating certain ASD traits such as favoring repetition. Twenty-four ASD adults and 24 neurotypical controls listened to three samples of repeated Japanese words for five minutes, and reported their percepts verbally whenever they experienced perceptual changes. As for the number of perceptual changes and that of reported forms, we found no significant difference between the ASD group and controls. However, the phonetic variations of form changes were different, and ASD group showed more phonetic variation than controls. We interpret the results from the viewpoint of unusual adaptation in auditory and/or phonetic processing.

A-63Relationship Between Neural Coherence in Gamma Frequency Band and Phonological Processing in Autism Spectrum Disorder

A-63Relationship Between Neural Coherence in Gamma Frequency Band and Phonological Processing in Autism Spectrum Disorder

Voice identity processing in autism spectrum disorder.

People with autism spectrum disorder (ASD) have difficulties in identifying another person by face and voice. This might contribute considerably to the development of social cognition and interaction difficulties. The characteristics of the voice recognition deficit in ASD are unknown. Here, we used a comprehensive behavioral test battery to systematically investigate voice processing in high-functioning ASD (n = 16) and typically developed pair-wise matched controls (n = 16). The ASD group had particular difficulties with discriminating, learning, and recognizing unfamiliar voices, while recognizing famous voices was relatively intact. Tests on acoustic processing abilities showed that the ASD group had a specific deficit in vocal pitch perception that was dissociable from otherwise intact acoustic processing (i.e., musical pitch, musical, and vocal timbre perception). Our results allow a characterization of the voice recognition deficit in ASD: The findings indicate that in high-functioning ASD, the difficulty to recognize voices is particularly pronounced for learning novel voices and the recognition of unfamiliar peoples' voices. This pattern might be indicative of difficulties with integrating the acoustic characteristics of the voice into a coherent percept-a function that has been previously associated with voice-selective regions in the posterior superior temporal sulcus/gyrus of the human brain. Autism Res 2017, 10: 155-168. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Altered Onset Response Dynamics in Somatosensory Processing in Autism Spectrum Disorder.

Abnormalities in cortical connectivity and evoked responses have been extensively documented in autism spectrum disorder (ASD). However, specific signatures of these cortical abnormalities remain elusive, with data pointing toward abnormal patterns of both increased and reduced response amplitudes and functional connectivity. We have previously proposed, using magnetoencephalography (MEG) data, that apparent inconsistencies in prior studies could be reconciled if functional connectivity in ASD was reduced in the feedback (top-down) direction, but increased in the feedforward (bottom-up) direction. Here, we continue this line of investigation by assessing abnormalities restricted to the onset, feedforward inputs driven, component of the response to vibrotactile stimuli in somatosensory cortex in ASD. Using a novel method that measures the spatio-temporal divergence of cortical activation, we found that relative to typically developing participants, the ASD group was characterized by an increase in the initial onset component of the cortical response, and a faster spread of local activity. Given the early time window, the results could be interpreted as increased thalamocortical feedforward connectivity in ASD, and offer a plausible mechanism for the previously observed increased response variability in ASD, as well as for the commonly observed behaviorally measured tactile processing abnormalities associated with the disorder.

Reduced sensitivity to context in language comprehension: A characteristic of Autism Spectrum Disorders or of poor structural language ability?

We present two experiments examining the universality and uniqueness of reduced context sensitivity in language processing in Autism Spectrum Disorders (ASD), as proposed by the Weak Central Coherence account (Happé & Frith, 2006, Journal of Autism and Developmental Disorders, 36(1), 25). That is, do all children with ASD exhibit decreased context sensitivity, and is this characteristic specific to ASD versus other neurodevelopmental conditions? Experiment 1, conducted in English, was a comparison of children with ASD with normal language and their typically-developing peers on a picture selection task where interpretation of sentential context was required to identify homonyms. Contrary to the predictions of Weak Central Coherence, the ASD-normal language group exhibited no difficulty on this task. Experiment 2, conducted in German, compared children with ASD with variable language abilities, typically-developing children, and a second control group of children with Language Impairment (LI) on a sentence completion task where a context sentence had to be considered to produce the continuation of an ambiguous sentence fragment. Both ASD-variable language and LI groups exhibited reduced context sensitivity and did not differ from each other. Finally, to directly test which factors contribute to reduced context sensitivity, we conducted a regression analysis for each experiment, entering nonverbal IQ, structural language ability, and autism diagnosis as predictors. For both experiments structural language ability emerged as the only significant predictor. These convergent findings demonstrate that reduced sensitivity to context in language processing is linked to low structural language rather than ASD diagnosis.

Evidence of Reduced Global Processing in Autism Spectrum Disorder

Frith’s original notion of ‘weak central coherence’ suggested that increased local processing in autism spectrum disorder (ASD) resulted from reduced global processing. More recent accounts have emphasised superior local perception and suggested intact global integration. However, tasks often place local and global processing in direct trade-off, making it difficult to determine whether group differences reflect reduced global processing, increased local processing, or both. We present two measures of global integration in which poor performance could not reflect increased local processing. ASD participants were slower to identify fragmented figures and less sensitive to global geometric impossibility than IQ-matched controls. These findings suggest that reduced global integration comprises one important facet of weak central coherence in ASD.

Hemispheric differences in language processing in autism spectrum disorders: A meta-analysis of neuroimaging studies.

Language impairments, a hallmark feature of autism spectrum disorders (ASD), have been related to neuroanatomical and functional abnormalities. Abnormal lateralization of the functional language network, increased reliance on visual processing areas, and increased posterior brain activation have all been reported in ASD and proposed as explanatory models of language difficulties. Nevertheless, inconsistent findings across studies have prevented a comprehensive characterization of the functional language network in ASD. The aim of this study was to quantify common and consistent patterns of brain activation during language processing in ASD and typically developing control (TD) participants using a meta-analytic approach. Activation likelihood estimation (ALE) meta-analysis was used to examine 22 previously published functional Magnetic Resonance Imaging (fMRI)/positron emission tomography studies of language processing (ASD: N = 328; TD: N = 324). Tasks included in this study addressed semantic processing, sentence comprehension, processing figurative language, and speech production. Within-group analysis showed largely overlapping patterns of language-related activation in ASD and TD groups. However, the ASD participants, relative to TD participants, showed: (1) more right hemisphere activity in core language areas (i.e., superior temporal gyrus and inferior frontal gyrus), particularly in tasks where they had poorer performance accuracy; (2) bilateral MTG hypo-activation across many different paradigms; and (3) increased activation of the left lingual gyrus in tasks where they had intact performance. These findings show that the hypotheses reviewed here address the neural and cognitive aspects of language difficulties in ASD across all tasks only in a limited way. Instead, our findings suggest the nuances of language and brain in ASD in terms of its context-dependency. Autism Res 2016, 9: 1046-1057. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Maturation of auditory neural processes in autism spectrum disorder - A longitudinal MEG study.

BackgroundIndividuals with autism spectrum disorder (ASD) show atypical brain activity, perhaps due to delayed maturation. Previous studies examining the maturation of auditory electrophysiological activity have been limited due to their use of cross-sectional designs. The present study took a first step in examining magnetoencephalography (MEG) evidence of abnormal auditory response maturation in ASD via the use of a longitudinal design.MethodsInitially recruited for a previous study, 27 children with ASD and nine typically developing (TD) children, aged 6- to 11-years-old, were re-recruited two to five years later. At both timepoints, MEG data were obtained while participants passively listened to sinusoidal pure-tones. Bilateral primary/secondary auditory cortex time domain (100 ms evoked response latency (M100)) and spectrotemporal measures (gamma-band power and inter-trial coherence (ITC)) were examined. MEG measures were also qualitatively examined for five children who exhibited “optimal outcome”, participants who were initially on spectrum, but no longer met diagnostic criteria at follow-up.ResultsM100 latencies were delayed in ASD versus TD at the initial exam (~ 19 ms) and at follow-up (~ 18 ms). At both exams, M100 latencies were associated with clinical ASD severity. In addition, gamma-band evoked power and ITC were reduced in ASD versus TD. M100 latency and gamma-band maturation rates did not differ between ASD and TD. Of note, the cohort of five children that demonstrated “optimal outcome” additionally exhibited M100 latency and gamma-band activity mean values in-between TD and ASD at both timepoints. Though justifying only qualitative interpretation, these “optimal outcome” related data are presented here to motivate future studies.ConclusionsChildren with ASD showed perturbed auditory cortex neural activity, as evidenced by M100 latency delays as well as reduced transient gamma-band activity. Despite evidence for maturation of these responses in ASD, the neural abnormalities in ASD persisted across time. Of note, data from the five children whom demonstrated “optimal outcome” qualitatively suggest that such clinical improvements may be associated with auditory brain responses intermediate between TD and ASD. These “optimal outcome” related results are not statistically significant though, likely due to the low sample size of this cohort, and to be expected as a result of the relatively low proportion of “optimal outcome” in the ASD population. Thus, further investigations with larger cohorts are needed to determine if the above auditory response phenotypes have prognostic utility, predictive of clinical outcome.

Visual orientation processing in autism spectrum disorder: No sign of enhanced early cortical function

It has been suggested that enhanced perceptual processing underlies some of the social difficulties associated with autism spectrum disorder (ASD). While a variety of visual tasks have been reported in which individuals with ASD outperform neurotypical individuals in control groups, the precise origin of such effects within the visual pathway remains unclear. It has recently been established that visual acuity is intact yet unremarkable in ASD. This suggests that the earliest levels of retinal processing are an unlikely candidate as the source of differences. The next potential levels for divergent visual processing are those involved in processing simple aspects of visual stimuli, such as orientation and spatial frequency, considered to be functions of early visual cortex. Here we focused on the basic processing of orientation. In three experiments, we assessed three basic aspects of orientation processing-discrimination, veridical perception, and detection-in participants with ASD in comparison to age-, gender-, and IQ-matched adults without ASD. Each experiment allowed for both qualitative and quantitative comparisons between the two groups. These provided a dense array of data indicating that participants with ASD perceive orientation of low-level stimuli in a qualitatively (as well as quantitatively) similar manner to participants without ASD in control groups, with no evidence of superior processing in detection, precision, or accuracy aspects of orientation perception. These results suggest that the source for altered perceptual abilities should be sought elsewhere, possibly in specific subgroups of people with ASD, other aspects of low-level vision such as spatial frequency, or subsequent levels of visual processing.

Do Individuals With Autism Spectrum Disorder Process Own- and Other-Race Faces Differently?

Individuals with autism spectrum disorder (ASD) process human faces in atypical ways according to previous literature. We investigated whether individuals with ASD can process face race information and respond to own- and other-race faces differentially. Chinese individuals with ASD (n = 24), typically developing (TD) individuals (n = 28), and individuals with intellectual disabilities (ID, n = 26) were asked to recognize Chinese and Caucasian faces in an old-new face paradigm using eye tracking. In terms of recognition, the ASD and ID groups did not perform differently and displayed superior own-race recognition compared with other-race faces; TD participants displayed similar recognition of the two types of faces. In terms of eye tracking, the TD, ASD, and ID groups displayed more looking on the eyes and less looking on the nose and mouth of Caucasian faces relative to Chinese faces. Overall, individuals with ASD manifested a behavioral other-race effect and displayed the same type of cross-racial differentiation in face scanning observed in TD individuals. The findings suggest that as is the case with TD individuals, face processing of individuals with ASD is influenced by differences in visual experience with different face categories.

Local and Global Visual Processing in Autism Spectrum Disorders: Influence of Task and Sample Characteristics and Relation to Symptom Severity.

Local and global visual processing abilities and processing style were investigated in individuals with autism spectrum disorder (ASD) versus typically developing individuals, children versus adolescents and boys versus girls. Individuals with ASD displayed more attention to detail in daily life, while laboratory tasks showed slightly reduced global processing abilities, intact local processing abilities, and a more locally oriented processing style. However, the presence of these group differences depended on particular task and sample (i.e., age and gender) characteristics. Most measures of local and global processing did not correlate with each other and were not associated with processing style. Significant associations between local-global processing and ASD symptom severity were observed, but the causality of these associations remains unclear.

Self-motion perception in autism is compromised by visual noise but integrated optimally across multiple senses

Perceptual processing in autism spectrum disorder (ASD) is marked by superior low-level task performance and inferior complex-task performance. This observation has led to theories of defective integration in ASD of local parts into a global percept. Despite mixed experimental results, this notion maintains widespread influence and has also motivated recent theories of defective multisensory integration in ASD. Impaired ASD performance in tasks involving classic random dot visual motion stimuli, corrupted by noise as a means to manipulate task difficulty, is frequently interpreted to support this notion of global integration deficits. By manipulating task difficulty independently of visual stimulus noise, here we test the hypothesis that heightened sensitivity to noise, rather than integration deficits, may characterize ASD. We found that although perception of visual motion through a cloud of dots was unimpaired without noise, the addition of stimulus noise significantly affected adolescents with ASD, more than controls. Strikingly, individuals with ASD demonstrated intact multisensory (visual-vestibular) integration, even in the presence of noise. Additionally, when vestibular motion was paired with pure visual noise, individuals with ASD demonstrated a different strategy than controls, marked by reduced flexibility. This result could be simulated by using attenuated (less reliable) and inflexible (not experience-dependent) Bayesian priors in ASD. These findings question widespread theories of impaired global and multisensory integration in ASD. Rather, they implicate increased sensitivity to sensory noise and less use of prior knowledge in ASD, suggesting increased reliance on incoming sensory information.

Neural mechanisms of negative reinforcement in children and adolescents with autism spectrum disorders.

BackgroundPrevious research has found accumulating evidence for atypical reward processing in autism spectrum disorders (ASD), particularly in the context of social rewards. Yet, this line of research has focused largely on positive social reinforcement, while little is known about the processing of negative reinforcement in individuals with ASD.MethodsThe present study examined neural responses to social negative reinforcement (a face displaying negative affect) and non-social negative reinforcement (monetary loss) in children with ASD relative to typically developing children, using functional magnetic resonance imaging (fMRI).ResultsWe found that children with ASD demonstrated hypoactivation of the right caudate nucleus while anticipating non-social negative reinforcement and hypoactivation of a network of frontostriatal regions (including the nucleus accumbens, caudate nucleus, and putamen) while anticipating social negative reinforcement. In addition, activation of the right caudate nucleus during non-social negative reinforcement was associated with individual differences in social motivation.ConclusionsThese results suggest that atypical responding to negative reinforcement in children with ASD may contribute to social motivational deficits in this population.