Backward masking: evidence of reduced subcortical amygdala engagement in autism

Recent data suggest that subthreshold presentation of emotional information is relayed to the amygdala along subcortical pathways. We examined the effect of backward masked neutral and anxious faces on the social decisions of a group of high functioning children with autism ages 7-13 years and matched controls. Participants were asked to select the friendliest of two faces, one of which was associated with the subthreshold (33 ms) presentation of an anxious face (A/N) and the other a subthreshold neutral face (N/N). Neutral paired faces were selected more often than A/N paired faces by both groups. However, children with autism selected significantly fewer N/N stimuli and more A/N stimuli than controls. These results suggest that the social choices of children with autism were influenced less by emotional information presented subconsciously and suggest a subcortical contribution to the social/emotional processing deficits observed in autism.     

孤独症儿童的情绪共情能力及情绪表情注意方式

研究探讨了孤独症儿童的情绪共情能力及情绪表情注意方式的特点。各选取15名孤独症儿童以及作为对照组的智力障碍儿童和普通儿童各15名, 完成情绪共情实验, 同时使用生物反馈仪记录自主生理反应, 眼动仪记录眼动轨迹。结果发现孤独症儿童对情绪表情的自动模仿及感知能力显著低于智力障碍儿童与普通儿童; 对面孔的总注视时间、总注视点数均显著少于智力障碍儿童、普通儿童; 对眼部、嘴部的注视时间比及注视点数比均显著低于普通儿童; 对高兴和悲伤表情的注意较多而对恐惧则较少。这提示孤独症儿童的情绪共情能力不足、对情绪表情的注意方式异常。     

Epileptic encephalopathies and their relationship to developmental disorders: do spikes cause autism?

Epileptic encephalopathies are progressive clinical and electroencephalographic syndromes where deterioration is thought to be caused by frequent seizures and abundant EEG epileptiform activity. Seizures occur in approximately 10-15% of children with pervasive developmental disorders (PDD) and 8-10% have epileptiform EEG abnormalities without seizures. Thirty percent of children with PDD have regression of social behavior and language at 2-3 years of age. Some authors speculate that the regression is caused by epileptiform activity even in the absence of overt clinical seizures ("autism with epileptic regression") and suggest that elimination of the epileptiform activity, either medically or surgically, should lead to improvement in behavior. This review examines the data showing that interictal epileptiform discharges are associated with transient clinical dysfunction and discusses the implications of these observations for autistic behavioral abnormalities. The results of resective surgery, vagal nerve stimulation, and multiple subpial transaction on children with autism and epileptiform EEG abnormalities are also discussed. I conclude that there is no evidence that interictal discharges per se cause (or contribute to) the complex behavioral phenotype of autism. There is no justification to support the use of anticonvulsant medication or surgery in children with PDD without seizures; that is, there is no evidence that treatment to eliminate EEG spikes will have a therapeutic effect on the behavioral abnormalities of PDD and autism.     

Temporal processing deficits in high‐functioning children with autism

It is well known that complex functions (e.g. perception, attention, memory, emotions, social interactions and language) are usually disturbed in autism. As these functions are characterized by specific temporal patterns, the present study examined whether children with autism show typical temporal processing in the time domain of a few seconds. Using a temporal‐reproduction paradigm, we found that they were unable to link their responses to stimulus duration. Independently of stimulus duration, they reproduced auditory or visual stimuli with the same response duration of, on average, 3 s. These results demonstrate important deficits in duration judgment in individuals with autism. As other experiments provide evidence for a temporal processing platform of ? 2 — 3 s in normal individuals, this platform may be preserved in a residual form in autism.     

Eye contact does not facilitate detection in children with autism

Eye contact is crucial in achieving social communication. Deviant patterns of eye contact behavior are found in individuals with autism, who suffer from severe social and communicative deficits. This study used a visual oddball paradigm to investigate whether children with high functioning autism have difficulty in detecting mutual gaze under experimental conditions. The results revealed that children with autism were no better at detecting direct gaze than at detecting averted gaze, which is unlike normal children. This suggests that whereas typically developing children have the ability to detect direct gaze, children with autism do not. This might result in altered eye-contact behavior, which hampers subsequent development of social and communicative skills.     

Young children with autism show atypical brain responses to fearful versus neutral facial expressions of emotion

Evidence suggests that autism is associated with impaired emotion perception, but it is unknown how early such impairments are evident. Furthermore, most studies that have assessed emotion perception in children with autism have required verbal responses, making results difficult to interpret. This study utilized high-density event-related potentials (ERPs) to investigate whether 3-4-year-old children with autism spectrum disorder (ASD) show differential brain activity to fear versus neutral facial expressions. It has been shown that normal infants as young as 7 months of age show differential brain responses to faces expressing different emotions. ERPs were recorded while children passively viewed photos of an unfamiliar woman posing a neutral and a prototypic fear expression. The sample consisted of 29 3-4-year-old children with ASD and 22 chronological age-matched children with typical development. Typically developing children exhibited a larger early negative component (N300) to the fear than to the neutral face. In contrast, children with ASD did not show the difference in amplitude of this early ERP component to the fear versus neutral face. For a later component, typically developing children exhibited a larger negative slow wave (NSW) to the fear than to the neutral face, whereas children with autism did not show a differential NSW to the two stimuli. In children with ASD, faster speed of early processing (i. e. N300 latency) of the fear face was associated with better performance on tasks assessing social attention (social orienting, joint attention and attention to distress). These data suggest that children with ASD, as young as 3 years of age, show a disordered pattern of neural responses to emotional stimuli.     

Auditory abnormalities in autism: toward functional distinctions among findings

Recently, findings on a wide range of auditory abnormalities among individuals with autism have been reported. To date, functional distinctions among these varied findings are poorly established. Such distinctions should be of interest to clinicians and researchers alike given their potential therapeutic and experimental applications. This review suggests three general trends among these findings as a starting point for future analyses. First, studies of auditory perception of linguistic and social auditory stimuli among individuals with autism generally have found impaired perception versus normal controls. Such findings may correlate with impaired language and communication skills and social isolation observed among individuals with autism. Second, studies of auditory perception of pitch and music among individuals with autism generally have found enhanced perception versus normal controls. These findings may correlate with the restrictive and highly focused behaviors observed among individuals with autism. Third, findings on the auditory perception of non-linguistic, non-musical stimuli among autism patients resist any generalized conclusions. Ultimately, as some researchers have already suggested, the distinction between impaired global processing and enhanced local processing may prove useful in making sense of apparently discordant findings on auditory abnormalities among individuals with autism.     

What do children with autism attend to during imitation tasks?

Individuals with autism show a complex profile of differences in imitative ability, including a general deficit in precision of imitating another’s actions and special difficulty in imitating nonmeaningful gestures relative to meaningful actions on objects. Given that they also show atypical patterns of visual attention when observing social stimuli, we investigated whether possible differences in visual attention when observing an action to be imitated may contribute to imitative difficulties in autism in both nonmeaningful gestures and meaningful actions on objects. Results indicated that (a) a group of 18 high-functioning 8- to 15-year-olds with autistic disorder, in comparison with a matched group of 13 typically developing children, showed similar patterns of visual attention to the demonstrator’s action but decreased attention to his face when observing a model to be imitated; (b) nonmeaningful gestures and meaningful actions on objects triggered distinct visual attention patterns that did not differ between groups; (c) the autism group demonstrated reduced imitative precision for both types of imitation; and (d) duration of visual attention to the demonstrator’s action was related to imitation precision for nonmeaningful gestures in the autism group.     

Atypical updating of face representations with experience in children with autism

Face identity aftereffects are significantly diminished in children with autism relative to typical children, which may reflect reduced perceptual updating with experience. Here, we investigated whether this atypicality also extends to non‐face stimulus categories, which might signal a pervasive visual processing difference in individuals with autism. We used a figural aftereffect task to measure directly perceptual updating following exposure to distorted upright faces, inverted faces and cars, in typical children and children with autism. A size‐change between study and test stimuli limited the likelihood that any processing atypicalities reflected group differences in adaptation to low‐level features of the stimuli. Results indicated that, relative to typical children, figural aftereffects for upright faces, but not inverted faces or cars, were significantly attenuated in children with autism. Moreover, the group difference was amplified when we isolated the ‘face‐selective’ component of the aftereffect, by partialling out the mid‐level shape adaptation common to upright and inverted face stimuli. Notably, the aftereffects of typical children were disproportionately larger for upright faces than for inverted faces and cars, but the magnitude of aftereffects of autistic children was not similarly modulated according to stimulus category. These findings are inconsistent with a pervasive adaptive coding atypicality relative to typical children, and suggest that reduced perceptual updating may constitute a high‐level, and possibly face‐selective, visual processing difference in children with autism.     

Early communication development and intervention for children with autism

Autism is a neurodevelopmental disorder defined by impairments in social and communication development, accompanied by stereotyped patterns of behavior and interest. The focus of this paper is on the early development of communication in autism, and early intervention for impairments in communication associated with this disorder. An overview of components of communication is provided. Communication characteristics that are diagnostic of autism are summarized, with consideration of the overlap between social and communication impairment, particularly for children with autism functioning at the prelinguistic level. Early communication development and predictors of communication functioning in autism are examined, based on a review of prospective and retrospective studies. The focus of the discussion then turns to intervention. Consideration is given to the rationale for beginning intervention as early in life as possible for children with autism. Implications of motor, imitation, and play deficits for communication-based intervention are examined. Finally, issues related to the design and delivery of intervention for young children with autism are presented, along with a review of the major early intervention approaches for autism.     

A replication of preference displacement research in children with autism spectrum disorder

The purpose of this paper was to replicate previous research on preference displacement with edible and leisure stimuli. In the present study, the experimenters evaluated preference displacement in 25 children with autism spectrum disorder using combined multiple stimulus without replacement preference assessments that consisted of highly preferred edible and leisure stimuli. In addition, the experimenters used a block randomization procedure to evaluate if assessment order influenced displacement outcomes. The experimenters observed patterns of complete displacement by edible stimuli for four participants and complete displacement by leisure stimuli for two participants; assessment order did not influence outcomes. The results and implications are discussed.     

A connectionist model of category learning by individuals with high-functioning autism spectrum disorder

Individuals with autism spectrum disorder (ASD) show atypical patterns of learning and generalization. We explored the possible impacts of autism-related neural abnormalities on perceptual category learning using a neural network model of visual cortical processing. When applied to experiments in which children or adults were trained to classify complex two-dimensional images, the model can account for atypical patterns of perceptual generalization. This is only possible, however, when individual differences in learning are taken into account. In particular, analyses performed with a self-organizing map suggested that individuals with high-functioning ASD show two distinct generalization patterns: one that is comparable to typical patterns, and a second in which there is almost no generalization. The model leads to novel predictions about how individuals will generalize when trained with simplified input sets and can explain why some researchers have failed to detect learning or generalization deficits in prior studies of category learning by individuals with autism. On the basis of these simulations, we propose that deficits in basic neural plasticity mechanisms may be sufficient to account for the atypical patterns of perceptual category learning and generalization associated with autism, but they do not account for why only a subset of individuals with autism would show such deficits. If variations in performance across subgroups reflect heterogeneous neural abnormalities, then future behavioral and neuroimaging studies of individuals with ASD will need to account for such disparities.     

Social stimulation and joint attention in young autistic children

The present study was designed to examine the effects of social stimulation on the joint attention behavior of 20 autistic children under 6 years of age, 20 receptive language-matched Down syndrome children, and 20 receptive language matched-normally-developing infants. Children's social and non-social engagement states were measured during two experimental play sessions and during free play with parent. For all groups, joint attention was increased when adult play behavior closely followed and was contingent on the behavior of the children; however, the autistic children were significantly less responsive to the experimental manipulation than control subjects. In contrast, the autistic children were no less responsive in terms of other forms of social engagement. Results are interpreted as supporting a model of joint attention deficits in autism that involves factors inherent to the disorder in transaction with social context.     

INCREASING COMPLEX SOCIAL BEHAVIORS IN CHILDREN WITH AUTISM: EFFECTS OF PEER-IMPLEMENTED PIVOTAL RESPONSE TRAINING

Two children with autism were taught to engage in a variety of complex social behaviors using peer-implemented pivotal response training (PRT), a set of procedures designed to increase motivation and promote generalization. Typical peers were taught to implement PRT strategies by modeling, role playing, and didactic instruction. After training, peers implemented the procedures in the absence of direct supervision in a classroom environment. After the intervention, both children with autism maintained prolonged interactions with the peer, initiated play and conversations, and increased engagement in language and joint attention behaviors. In addition, teachers reported positive changes in social behavior, with the largest increases in peer-preferred social behavior. Further, these effects showed generality and maintenance. Implications of these findings are discussed.     

Effects of video self-modeling on the preference and reinforcer value of toys for children diagnosed with autism spectrum disorder

A primary characteristic of autism spectrum disorder includes restrictive and repetitive patterns of behavior. Because having few preferred items and activities can lead to social, communicative, and educational barriers, it is important to increase the number of preferred stimuli in the individual's environment. One way to do this is through conditioned reinforcement via observation. Such procedures involve the acquisition of a skill or change in behavior as a result of indirect contact (i.e., observation) with contingencies received by others. While conditioning through observation has been shown to be effective, one novel approach is video self-modeling. The purpose of the current study was to assess the effects of video self-modeling on the preference and reinforcer value of toys for children diagnosed with autism spectrum disorder.     

Drawing self and others: How do children with autism differ from those with learning difficulties?

When children draw pictures of human beings, they reveal things not only about their general intellectual and artistic abilities, but also about their awareness and conception of themselves and others. What might the human figure drawings of children with autism reveal about their images of self and other – and what might they disclose about social factors that shape the drawings of children who do not have autism? On the basis of an hypothesis about the restricted social awareness of children and adolescents with autism, we predicted that there would be little differentiation between their drawings of themselves and other people. To test this prediction, we investigated a group of children and adolescents with autism and a group with learning difficulties but not autism (N = 14 per group) who were individually matched for both chronological age and verbal mental age. Participants with autism mostly drew human figures that were little distinguished from one another, but introduced clear contrasts among their houses, whereas most of those with learning difficulties drew distinctive human figures as well as houses. These different profiles of performance occurred despite similarities in the numbers and kinds of feature included in the drawings, and the individuality of participants' drawing styles. Although the results were in keeping with our hypothesis that human figure drawings might reflect abnormalities in the way that children with autism mentally represent themselves and others, we conclude by stressing our tentativeness over this interpretation of the findings.     

PROGRAMMING PARTICIPATION IN FAMILY ACTIVITIES FOR CHILDREN WITH AUTISM: PARENTS' USE OF PHOTOGRAPHIC ACTIVITY SCHEDULES

The parents of 3 boys with autism were taught to help their children follow photographic activity schedules depicting a variety of home-living tasks. A multiple baseline across participants showed that the home-based intervention produced increases in children's engagement and social initiations and decreases in disruptive behavior, which were maintained for as long as 10 months.     

Brain development in autism: early overgrowth followed by premature arrest of growth

Due to the relatively late age of clinical diagnosis of autism, the early brain pathology of children with autism has remained largely unstudied. The increased use of retrospective measures such as head circumference, along with a surge of MRI studies of toddlers with autism, have opened a whole new area of research and discovery. Recent studies have now shown that abnormal brain overgrowth occurs during the first 2 years of life in children with autism. By 2-4 years of age, the most deviant overgrowth is in cerebral, cerebellar, and limbic structures that underlie higher-order cognitive, social, emotional, and language functions. Excessive growth is followed by abnormally slow or arrested growth. Deviant brain growth in autism occurs at the very time when the formation of cerebral circuitry is at its most exuberant and vulnerable stage, and it may signal disruption of this process of circuit formation. The resulting aberrant connectivity and dysfunction may lead to the development of autistic behaviors. To discover the causes, neural substrates, early-warning signs and effective treatments of autism, future research should focus on elucidating the neurobiological defects that underlie brain growth abnormalities in autism that appear during these critical first years of life.     

Enhanced perceptual processing of speech in autism

Theories of autism have proposed that a bias towards low-level perceptual information, or a featural/surface-biased information-processing style, may compromise higher-level language processing in such individuals. Two experiments, utilizing linguistic stimuli with competing low-level/perceptual and high-level/semantic information, tested processing biases in children with autism and matched controls. Whereas children with autism exhibited superior perceptual processing of speech relative to controls, and showed no evidence of either a perceptual or semantic processing bias, controls showed a tendency to process speech semantically. The data provide partial support to the perceptual theories of autism. It is additionally proposed that the pattern of results may reflect different patterns of attentional focusing towards single or multiple stimulus cues in speech between children with autism and controls.     

Effects of multiple versus chained schedules on stereotypy and item engagement

We evaluated rates of automatically reinforced stereotypy and item engagement for 2 children with autism under multiple and chained schedules in a multielement design. Each schedule included components during which stereotypy was blocked (S–) or allowed (S+), and we used colored cards as schedule‐correlated stimuli. We report rates of stereotypy and item engagement during S– and S+ components, as well as the percentage of component time that elapsed before the first instances of stereotypy and item engagement. We observed less stereotypy and more consistent item engagement during chained‐schedule sessions, and stimulus control of stereotypy and item engagement was established with the chained schedule. A subsequent concurrent‐chains analysis revealed participant preference for the chained schedule. These results highlight the importance of contingent access to stereotypy when therapists attempt to gain stimulus control of stereotypy and increase functional item engagement.