Evidence for executive dysfunction in autism

A new semi-nonverbal task glance, moderate role of cognitive flexibility in ADHD children's theory of mind

Introduction: Studies have documented both executive functions (EF) impairment in children with Attention Deficit / Hyperactivity Disorders (ADHD) and Theory of Mind (ToM), yielding mixed results, possibly because of a variety of tasks used, all requiring different levels of language skills.Aim: To investigate the relationship between ToM and EF with non-language-based tasks.Methods: Thirty ADHD (7-9 years old) were compared to thirty controls (age and IQ matched). Participants' ToM was assessed using the Animated Triangles task and two EF tasks, namely spatial control test, the Stockings Of Cambridge (SOC) and rule and acquisition test, the Intra-Extra Dimensional set shift (IED)-from the neuropsychological battery of the Cambridge Neuropsychological Test Automated Battery (CANTAB).Results: ADHD group had a significant ToM and EF impairment relative to the control group. ToM was not significantly correlated with EF; however, the performance on IED tasks affected the performance on ToM tasks.Discussion: The study provides evidence for a link between the abilities to attribute correct mental states to others, planning and shifting attention in ADHD children, suggesting the ability to rely on cognitive flexibility in the face of a changing environment plays a role in explaining the association between ToM and EF.

Theory of mind across lifespan from ages 16 to 81 years

PURPOSE

Impaired theory of mind (ToM) is a neurobehavioral phenotype of epilepsy. Given that the age transitions affect cognitive development and decline, it is important to refine ToM across the lifespan. This study evaluated ToM in healthy subjects, taking into account education, gender, and other functions, aiming to clarify its specificity and relationships to major demographic and cognitive domains.

METHODS

A hundred and seventy subjects from ages 16 to 81 years (68 men) who received five to 17 years of schooling were evaluated using a Faux Pas Task (FPT) that is solved at the end of childhood and is highly sensitive to brain damage and tests for language, memory, praxis, visual perception, initiative, attention, shifting, and planning. Factor analysis, analysis of variance, and correlation and regression analyses were used to assess the data.

RESULTS

The analysis yielded six factors: Beliefs, Delusions, and Facts, which express the understanding of mental states and contextual details; Matching-Learning, Executive, and Working Memory. On this basis, six composite scores (CSs) were computed. Age and schooling showed significant effects on the Matching-Learning, Executive, and Working Memory CSs. The FPT raw scores and CSs were unrelated to age or schooling, while females showed better performance than males. The Beliefs CS and FPT scores were predicted by the Executive, Working Memory, Delusions, and Facts CSs and gender.

CONCLUSIONS

Theory of mind is a specific cognitive domain independent of age and formal education, but related to gender. Working memory, executive functions, and reality examination support some ToM processes. These findings may provide reference points against which impairment can be assessed. This article is part of the Special Issue "Epilepsy and social cognition across the lifespan".

Selective Pragmatic Impairment in Autism Spectrum Disorder: Indirect Requests Versus Irony

Autism Spectrum Disorder (ASD) is often described as being characterised by a uniform pragmatic impairment. However, recent evidence suggests that some areas of pragmatic functioning are preserved. This study seeks to determine to which extent context-based derivation of non-linguistically encoded meaning is functional in ASD. We compare the performance of 24 adults with ASD, and matched neuro-typical adults in two act-out pragmatic tasks. The first task examines generation of indirect request interpretations, and the second the comprehension of irony. Intact contextual comprehension of indirect requests contrasts with marked difficulties in understanding irony. These results suggest that preserved pragmatics in ASD is limited to egocentric processing of context, which does not rely on assumptions about the speaker's mental states.

Identifying set-switching difficulties in autism spectrum disorder using a rule following task

OBJECTIVES

The aim of the study is to distinguish between perceptuomotor and cognitive inflexibility as the source of set-switching difficulties in children with autism spectrum disorder (ASD).

METHODS

Seventeen adolescents with ASD and 17 neurotypical controls were presented with a computerized sequencing game using colored shapes. The sequence required a shift in perceptuomotor responding that could also be represented at a conceptual level. Measures of perceptuomotor inflexibility were based on errors and response times specifically on the critical switch item in the sequence. The task included three transfer phases in which the same rule was to be applied to new shapes and colors. Higher-order rule conceptualization was operationalized as the ability to abstract the switching rule and apply it across these phases.

RESULTS

Participants with ASD showed predicted difficulties on the perceptuomotor shift, but no deficit on the transfer phases.

CONCLUSIONS

The study indicates a problem with perceptuomotor inflexibility in ASD that can explain why 'extra-dimensional' shifting is sometimes reported as problematic in this group. Implications for difficulties in more real-world contexts are discussed.

Reduced prefrontal hemodynamic response in pediatric autism spectrum disorder measured with near-infrared spectroscopy

BACKGROUND

Functional neuroimaging studies suggest that prefrontal cortex dysfunction is present in people with autism spectrum disorder (ASD). Near-infrared spectroscopy is a noninvasive optical tool for examining oxygenation and hemodynamic changes in the cerebral cortex by measuring changes in oxygenated hemoglobin.

METHODS

Twelve drug-naïve male participants, aged 7-15 years and diagnosed with ASD according to DSM-5 criteria, and 12 age- and intelligence quotient (IQ)-matched healthy control males participated in the present study after giving informed consent. Relative concentrations of oxyhemoglobin were measured with frontal probes every 0.1 s during the Stroop color-word task, using 24-channel near-infrared spectroscopy.

RESULTS

Oxyhemoglobin changes during the Stroop color-word task in the ASD group were significantly smaller than those in the control group at channels 12 and 13, located over the dorsolateral prefrontal cortex (FDR-corrected P: 0.0021-0.0063).

CONCLUSION

The results suggest that male children with ASD have reduced prefrontal hemodynamic responses, measured with near-infrared spectroscopy.

A Visual Two-Choice Rule-Switch Task for Head-Fixed Mice

Cognitive flexibility is the innate ability of the brain to change mental processes and to modify behavioral responses according to an ever-changing environment. As our brain has a limited capacity to process the information of our surroundings in any given moment, it uses sets as a strategy to aid neural processing systems. With assessing the capability of shifting between task sets, it is possible to test cognitive flexibility and executive functions. The most widely used neuropsychological task for the evaluation of these functions in humans is the Wisconsin Card Sorting Test (WCST), which requires the subject to alter response strategies and use previously irrelevant information to solve a problem. The test has proven clinical relevance, as poor performance has been reported in multiple neuropsychiatric conditions. Although, similar tasks have been used in pre-clinical rodent research, many are limited because of their manual-based testing procedures and their hardware attenuates neuronal recordings. We developed a two-choice rule-switch task whereby head-fixed C57BL/6 mice had to choose correctly one of the two virtual objects presented to retrieve a small water reward. The animals learnt to discriminate the visual cues and they successfully switched their strategies according to the related rules. We show that reaching successful performance after the rule changes required more trials in this task and that animals took more time to execute decisions when the two rules were in conflict. We used optogenetics to inhibit temporarily the medial prefrontal cortex (mPFC) during reward delivery and consumption, which significantly increased the number of trials needed to perform the second rule successfully (i.e., succeed in switching between rules), compared to control experiments. Furthermore, by assessing two types of error animals made after the rule switch, we show that interfering with the positive feedback integration, but leaving the negative feedback processing intact, does not influence the initial disengagement from the first rule, but impedes the maintenance of the newly acquired response set. These findings support the role of prefrontal networks in mice for cognitive flexibility, which is impaired during numerous neuropsychiatric diseases, such as schizophrenia and depression.

A meta-analysis of working memory in individuals with autism spectrum disorders

BACKGROUND

Autism spectrum disorders (ASD) are lifelong neurodevelopmental disorders. It is not clear whether working memory (WM) deficits are commonly experienced by individuals with ASD.

AIM

To determine whether individuals with ASD experience significant impairments in WM and whether there are specific domains of working memory that are impaired.

METHODS

We conducted a meta-analysis using four electronic databases EMBASE (OVID), MEDLINE (OVID), PsychINFO (EBSCOHOST), and Web of Science, to examine the literature to investigate whether people with ASD experience impairments related to WM. Meta-analyses were conducted separately for phonological and visuospatial domains of WM. Subgroup analyses investigated age and intelligence quotient as potential moderators.

RESULTS

A total of 29 papers containing 34 studies measuring phonological and visuospatial domains of WM met the inclusion criteria. WM scores were significantly lower for individuals with ASD compared to typically developed (TD) controls, in both the visuospatial domain when investigating accuracy (d: -0.73, 95% CI -1.04 to -0.42, p < 0.05) and error rates (d: 0.56, 95% CI 0.25 to 0.88, p<0.05), and the phonological domain when investigating accuracy (d:-0.67, 95% CI -1.10 to -0.24, p>0.05) and error rate (d: 1.45, 95% CI -0.07 to 2.96, p = 0.06). Age and IQ did not explain the differences in WM in ASD.

CONCLUSIONS

The findings of this meta-analysis indicate that across the lifespan, individuals with ASD demonstrate large impairments in WM across both phonological and visuospatial WM domains when compared to healthy individuals.

Successful attentional set-shifting in 2-year-olds with and without Autism Spectrum Disorder

The development of executive function is necessary for flexible and voluntary control of behavior. Deficits in executive function are purported to be a primary cause of behavioral inflexibility—a core clinical symptom—in Autism Spectrum Disorder (ASD). Attentional set-shifting has traditionally been measured with the Dimensional Change Card Sort, however, this task requires following verbal instructions. Here, we used a novel visual search task that does not require verbal instructions in conjunction with eye-tracking to test attentional set-shifting in 2-year-old toddlers diagnosed with ASD (N = 29) and chronological age-matched typically developing controls (N = 30). On each trial, a relevant and an irrelevant target were embedded in a set of feature-conjunction distractors, and toddlers were tasked with searching for the relevant target. Critically, after a set of trials the targets switched roles (i.e., the previously relevant target became irrelevant, and the previously relevant target became irrelevant). We measured visual search performance prior to and following a target switch. We found that both groups of toddlers could readily switch targets, and found strikingly similar performance between typically developing toddlers and toddlers with ASD. Our results challenge the centrality of deficits in attentional set-shifting to early behavioral inflexibility in ASD.

Identifying the Cognitive Correlates of Reciprocity in Children with Autism Spectrum Disorder

This study examined the cognitive correlates of reciprocity in children with autism spectrum disorder (ASD). A total of 59 children with ASD were assessed with the Interactive Drawing Task, Theory of Mind Task Battery, Children's Card Change Sort Task, and Children's Gambling Task respectively for their reciprocity, theory of mind, cool executive function (EF), and hot EF. The correlational findings revealed that cool EF (r = .482 and - .501, p < .01) and hot EF (r = .396, p < .05) were significantly correlated with children's total reciprocity. The regression models also showed that cool and hot EF abilities were significant predictors. Conclusively, cool and hot EF abilities are the correlates of reciprocity rather than of ToM in children with ASD.

Executive Function in Autism Spectrum Disorder: History, Theoretical Models, Empirical Findings, and Potential as an Endophenotype

This review presents an outline of executive function (EF) and its application to autism spectrum disorder (ASD). The development of the EF construct, theoretical models of EF, and limitations in the study of EF are outlined. The potential of EF as a cognitive endophenotype for ASD is reviewed, and the Research Domain Criteria (RDoC) framework is discussed for researching EF in ASD given the multifaceted factors that influence EF performance. A number of executive-focused cognitive models have been proposed to explain the symptom clusters observed in ASD. Empirical studies suggest a broad impairment in EF, although there is significant inter-individual variability in EF performance. The observed heterogeneity of EF performance is considered a limiting factor in establishing EF as a cognitive endophenotype in ASD. We propose, however, that this variability in EF performance presents an opportunity for subtyping within the spectrum that can contribute to targeted diagnostic and intervention strategies. Enhanced understanding of the neurobiological basis that underpins EF performance, such as the excitation/inhibition hypothesis, will likely be important. Application of the RDoC framework could provide clarity on the nature of EF impairment in ASD with potential for greater understanding of, and improved interventions for, this disorder.

Prenatal vitamin D deficiency does not exacerbate behavioural impairments associated with prenatal ethanol exposure in juvenile male mice

There is a high prevalence of vitamin D deficiency and exposure to low levels of ethanol in pregnant women. However, there are a paucity of studies that have addressed the impact of both vitamin D deficiency and ethanol exposure on the offspring's vulnerability to neurodevelopmental disorders later in life. The aim of this study was to examine whether the absence of vitamin D during gestation in mice would alter the effects of prenatal exposure to low dose ethanol on the behaviour and dopaminergic gene expression patterns of juvenile mice. Four-week old female C57BL/6J mice were placed on a prenatal vitamin D deficient (PVD) or standard diet for 6 weeks and mated at 10 weeks of age. Females were exposed to either 10%(v/v) ethanol or water between gestational days 0-8 and all were offered water thereafter. We found that blood ethanol concentration in the dams was not affected by maternal diet. Behavioural analyses of the offspring included ultrasonic vocalizations (USV) at postnatal day (P) 7, locomotion and social interaction at P21. The main findings were increased USV calling rate and impaired social interaction in males with prenatal ethanol exposure (PrEE). Gene expression analysis of transcripts involved in dopamine regulation revealed a main effect of ethanol exposure on dopamine- and cyclic adenosine monophosphate- regulated neuronal phosphoprotein (Darpp-32), a main effect of vitamin D diet on Dopamine 2 Receptors (D2R) and a main effect of Sex on Tyrosine Hydroxylase (TH) expression. The combination of PVD-PrEE did not exacerbate the alterations resulting from PVD or PrEE. Despite the limited evidence to support the interaction of PVD and PrEE during the postnatal period, males were more vulnerable than female offspring to the detrimental effects of PrEE. Therefore, based on these studies in mice we suggest that maintenance of optimal vitamin D levels and abstinence from ethanol during pregnancy would reduce risk of later disruption to brain function and behaviour in the offspring.

Good social skills despite poor theory of mind: exploring compensation in autism spectrum disorder

BACKGROUND

It is proposed that some individuals with Autism Spectrum Disorder (ASD) can 'compensate' for their underlying difficulties (e.g. in theory of mind; ToM), thus demonstrating relatively few behavioural symptoms, despite continued core cognitive deficits. The mechanisms underpinning compensation are largely unexplored, as is its potential impact on mental health. This study aimed to estimate compensation patterns in ASD, by contrasting overt social behaviour with ToM task performance, in order to compare the characteristics of 'Low' and 'High' Compensators.

METHODS

A total of 136 autistic adolescents, from the ongoing Social Relationships Study, completed a range of cognitive tasks, the Autistic Diagnostic Observation Schedule (ADOS) and a self-report anxiety questionnaire. Participants were assigned compensation group status; High Compensators demonstrated good ADOS scores despite poor ToM performance, while Low Compensators demonstrated similarly poor ToM, accompanied by poor ADOS scores.

RESULTS

High Compensators demonstrated better IQ and executive function (EF), but greater self-reported anxiety, compared with Low Compensators. Such differences were not found when comparing individuals who had good versus poor ADOS scores, when ToM performance was good. Other core autistic characteristics (weak central coherence, nonsocial symptoms) did not differentiate the High and Low Compensators.

CONCLUSIONS

IQ, EF and anxiety appear to be implicated in the processes by which certain autistic young people can compensate for their underlying ToM difficulties. This tendency to compensate does not appear to reflect the severity of 'hit' for ASD per se, suggesting that well-compensated individuals are not experiencing a milder form of ASD. The construct of compensation in ASD has implications for research and clinical practice.

Discrepancies When Assessing Interpersonal Problem-Solving Skills in Autism Spectrum Disorder: A Diagnostic Indicator

In children with autism spectrum disorder (ASD), there are often discrepancies between direct assessment and third-party reports. We compared these children with groups with/without difficulties in interpersonal problem-solving skills in order to determine whether these discrepancies appear and if they could be a diagnostic indicator for ASD. There were 91 participants (ages 7-13): 28 children with ASD, 36 in a high family risk situation, and 27 typically developing children, all tested with direct measures and third-party reports. Results showed discrepancies only in the ASD group. Consequently, direct performance measures and third-party reports seem to be evaluating different constructs in children with ASD. In addition, both types of measures discriminate between groups, such that both are needed, especially in diagnostic assessments.

Differences in means-end exploration between infants at risk for autism and typically developing infants in the first 15 months of life

Our study compared means-end exploration in infants at risk (AR) for autism and typically developing (TD) infants using a nested box paradigm. Sixteen AR and 16 TD infants were observed at 9, 12, and 15 months with follow-up at 18 and 24 months. We collected video data on three tasks involving retrieval of a small toy by opening (a) an opaque box, (b) a transparent box, and (c) two nested boxes. Dependent variables included hand bias, time to completion, bilateral hand use, problem-solving strategies used, and tester assistance required. There were no group differences in terms of hand biases. Compared to TD infants, AR infants had lower bilateral hand use, poor problem solving skills, and required greater assistance. Both groups demonstrated age-related improvements in motor and cognitive skills. Means-end exploration provides a window into the bilateral coordination and motor planning/problem-solving abilities of young infants at risk for autism. Lastly, object retrieval tasks could serve as important learning contexts for at-risk infants.

Infant quantitative risk for autism spectrum disorder predicts executive function in early childhood

Much of the current research concerning autism spectrum disorder (ASD) focuses on early identification of behaviors that may indicate future deficits or higher risk for a later diagnosis. Additionally, there exists a strong claim regarding the dimensional nature of ASD, such that even among non-diagnosed individuals, a continuous distribution of symptom severity can be observed. Executive function (EF) has been widely studied in children, adolescents, and adults with ASD, with a robust body of research supporting widespread EF deficits in diagnosed individuals. However, it remains unclear how the degree of ASD symptomatology, outside of the presence of a diagnosis, affects EF abilities in a community sample. The First Year Inventory 2.0 (FYI 2.0), a parent-report measure, was designed to identify infants at 12 months who are at risk for an eventual ASD diagnosis. In the current study, a continuous scoring scale was used to examine risk (overall, Social-Communication, and Sensory-Regulatory) from a dimensional perspective. Parents also completed the Behavior Rating Inventory of Executive Function-Preschool Version and the Social Responsiveness Scale-2nd edition when their children were 42 months (3.5 years) old. Each FYI 2.0 risk variable significantly predicted scores on an overall EF composite and specific EF subscales. When controlling for general ASD symptomatology, Sensory-Regulatory risk still significantly predicted EF deficits. This research provides additional support for a quantitative consideration of risk for ASD and presents novel findings regarding the relation between infant behaviors indicative of ASD risk and EF in early childhood. Autism Research 2018, 11: 1532-1541. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Children with autism spectrum disorder (ASD) often have difficulty with executive function (EF) tasks that require a set of mental processes involved in goal-directed behaviors. Studying children without ASD who may have symptoms affecting EF is also important. This study demonstrates that certain infant behaviors related to ASD are linked to early childhood EF difficulties. These results support looking at a range of ASD symptoms to better understand children who struggle with EF and potentially design tools to help them.

Behavioural flexibility of children with Autism Spectrum Disorder on a card-sorting task with varying task difficulty

Inflexibility is taken to be a key characteristic of Autism Spectrum Disorder (ASD), although it is unclear which aspect of cognitive functioning is critical in this context. The current study investigated task-switching problems and inflexibility with a group of children with ASD, and a mental-aged matched control group. Participants (n = 50; mean age = 7 years) completed two card-sorting tasks, which involved learning to sort by either two or three possible dimensions, and then the sorting rule was switched although the number of dimensions required to sort the cards remained the same. Following the sorting rule change, the ASD group made more errors compared to controls. Errors were also related to task type (two or three dimensions), but this was not found to interact with ASD. If poor performance were solely dependent on executive function (working memory) problems in ASD, then a steeper decrease in performance with an increase in task difficulty for one group, compared to another group, would be expected. The current results suggest that task difficulty is an aspect of importance in set-shifting, but shifting is not differentially affected by this component.

Wait…What??? Guiding Intervention Principles for Students With Verbal Working Memory Limitations

Purpose

The purpose of this clinical focus article is to present 5 guiding principles for the development of interventions for children with limited verbal working memory abilities.

Method

Summarizing and synthesizing previously reported theories and empirical data, we present a framework intended to guide working memory interventions.

Results

Existing research and theory support a comprehensive, multidimensional treatment model that considers the knowledge and abilities of the student and the language-learning demands they face in the various contexts of a school day.

Conclusion

The clinical framework for which we are advocating is one that embodies the characteristics of complex interventions—those made up of many individual components that work synchronously in conjunction with each other.

Embryonic stem cell transplants as a therapeutic strategy in a rodent model of autism

Autism is a neurodevelopmental disorder characterized by disruptions in three core behavioral domains: deficits in social interaction, impairments in communication, and repetitive and stereotyped patterns of behavior or thought. There are currently no drugs available for the treatment of the core symptoms of ASD and drugs that target comorbid symptoms often have serious adverse side effects, suggesting an urgent need for new therapeutic strategies. The neurobiology of autism is complex, but converging evidence suggests that ASD involves disruptions in the inhibitory GABAergic neurotransmitter system. Specifically, people with autism have a reduction in parvalbumin (PV)-containing interneurons in the PFC, leading to the suggestion that restoring interneuron function in this region may be a novel therapeutic approach for ASD. Here we used a dual-reporter embryonic stem cell line to generate enriched populations of PV-positive interneurons, which were transplanted into the medial prefrontal cortex (mPFC) of the Poly I:C rodent model of autism. PV interneuron transplants were able to decrease pyramidal cell firing in the mPFC and alleviated deficits in social interaction and cognitive flexibility. Our results suggest that restoring PV interneuron function in the mPFC may be a novel and effective treatment strategy to reduce the core symptoms of autism.

Is Poor Working Memory a Transdiagnostic Risk Factor for Psychopathology?

In contrast to historical conceptualizations that framed psychological disorders as distinct, categorical conditions, it is now widely understood that co- and multi-morbidities between disorders are extensive. As a result, there has been a call to better understand the dimensional liabilities that are common to and influence the development of multiple psychopathologies, as supported and exemplified by the National Institutes of Mental Health (NIMH) Research Domain Criteria (RDoC) framework. We use a latent variable SEM approach to examine the degree to which working memory deficits represent a cognitive liability associated with the development of common and discrete dimensions of psychopathology. In a sample of 415 community recruited children aged 8-12 (n = 170 girls), we fit a bi-factor model to parent reports of behavior from the DISC-4 and BASC-2, and included a latent working memory factor as a predictor of the internalizing, externalizing, and general "p-factor." We found that both the general "p-factor" and externalizing (but not internalizing) latent factor were significantly associated with working memory. When a bi-factor model of externalizing symptomology was fit to further explore this relationship, working memory was only correlated with the general externalizing dimension; correlation with specific inattention, hyperactive/impulsive, and oppositional factors did not survive once the general externalizing dimension was taken into consideration. These findings held regardless of the sex of the child. Our results suggest that working memory deficits represent both a common cognitive liability for mental health disorders, and a specific liability for externalizing disorders.

Computerized Cognitive Training in Children With Autism and Intellectual Disabilities: Feasibility and Satisfaction Study

BACKGROUND

Researchers are increasingly interested in testing and developing computerized cognitive training interventions for individuals with autism spectrum disorder due to the limited accessibility of treatments for this disorder. Understanding the feasibility of testing cognitive interventions for this population is critical, especially for individuals with ASD who have low to moderate intellectual ability.

OBJECTIVE

The aim of the study was to evaluate the feasibility of computerized cognitive training as measured by attrition rate and a parent satisfaction survey.

METHODS

A total of 26 participants aged 8-17 years with an autism spectrum disorder diagnosis and significant intellectual impairment were enrolled (mean age 11.1 years). They were instructed to complete 25 sessions of Cogmed Working Memory Training in 5 to 6 weeks with coach assistance. Attrition rate and parent satisfaction surveys were measured after the completion of training.

RESULTS

Most participants (96%, 25/26) completed the training and indicated high satisfaction (>88%). However, among the participants who completed the training, 5 participants (19%) were unable to finish in 6 weeks, the recommended training period by Cogmed. Parents noted various positive (eg, voice-overs) and negative (eg, particular graphic and sounds associated with a stimulus) features of the game that they thought affected their child's response.

CONCLUSIONS

Children with autism spectrum disorder and intellectual impairments can successfully participate in computerized cognitive training interventions but may require additional weeks to complete the training beyond the time needed for children without intellectual impairments. The overall completion rate, with extended time to complete the training, was high. Developers of cognitive training programs for this population should take into account potential issues regarding the noise level of stimuli and characteristics of the visual graphics.

PV Interneurons: Critical Regulators of E/I Balance for Prefrontal Cortex-Dependent Behavior and Psychiatric Disorders

Elucidating the prefrontal cortical microcircuit has been challenging, given its role in multiple complex behaviors, including working memory, cognitive flexibility, attention, social interaction and emotional regulation. Additionally, previous methodological limitations made it difficult to parse out the contribution of certain neuronal subpopulations in refining cortical representations. However, growing evidence supports a fundamental role of fast-spiking parvalbumin (PV) GABAergic interneurons in regulating pyramidal neuron activity to drive appropriate behavioral responses. Further, their function is heavily diminished in the prefrontal cortex (PFC) in numerous psychiatric diseases, including schizophrenia and autism. Previous research has demonstrated the importance of the optimal balance of excitation and inhibition (E/I) in cortical circuits in maintaining the efficiency of cortical information processing. Although we are still unraveling the mechanisms of information representation in the PFC, the E/I balance seems to be crucial, as pharmacological, chemogenetic and optogenetic approaches for disrupting E/I balance induce impairments in a range of PFC-dependent behaviors. In this review, we will explore two key hypotheses. First, PV interneurons are powerful regulators of E/I balance in the PFC, and help optimize the representation and processing of supramodal information in PFC. Second, diminishing the function of PV interneurons is sufficient to generate an elaborate symptom sequelae corresponding to those observed in a range of psychiatric diseases. Then, using this framework, we will speculate on whether this circuitry could represent a platform for the development of therapeutic interventions in disorders of PFC function.

Executive Functions and Prosodic Abilities in Children With High-Functioning Autism

Little is known about the relationship between prosodic abilities and executive function skills. As deficits in executive functions (EFs) and prosodic impairments are characteristics of autism, we examined how EFs are related to prosodic performance in children with high-functioning autism (HFA). Fifteen children with HFA (M = 7.4 years; SD = 1.12), matched to 15 typically developing peers on age, gender, and non-verbal intelligence participated in the study. The Profiling Elements of Prosody in Speech-Communication (PEPS-C) was used to assess prosodic performance. The Children's Color Trails Test (CCTT-1, CCTT-2, and CCTT Interference Index) was used as an indicator of executive control abilities. Our findings suggest no relation between prosodic abilities and visual search and processing speed (assessed by CCTT-1), but a significant link between prosodic skills and divided attention, working memory/sequencing, set-switching, and inhibition (assessed by CCTT-2 and CCTT Interference Index). These findings may be of clinical relevance since difficulties in EFs and prosodic deficits are characteristic of many neurodevelopmental disorders. Future studies are needed to further investigate the nature of the relationship between impaired prosody and executive (dys)function.

Co-occurring psychiatric conditions in autism spectrum disorder

Individuals with autism spectrum disorder (ASD) are at increased risk for experiencing one or more co-occurring psychiatric conditions. When present, these conditions are associated with additional impairment and distress. It is therefore crucial that clinicians and researchers adequately understand and address these challenges. However, due to symptom overlap, diagnostic overshadowing, and ambiguous symptom presentation in ASD, the assessment of co-occurring conditions in ASD is complex and challenging. Likewise, individual difference factors, such as age, intellectual functioning, and gender, may influence the presentation of co-occurring symptoms. Relatedly, a transdiagnostic framework may offer utility in assessing and treating co-occurring conditions. However, with the exception of anxiety disorders, treatment research for co-occurring psychiatric conditions in ASD is relatively limited. Therefore, the present paper aims to summarize and review available research on the most common co-occurring psychiatric disorders in ASD, with a focus on estimated population-based prevalence rates, diagnostic challenges, the influence of individual differences, and assessment guidelines. The utility of a transdiagnostic framework for conceptualizing co-occurring disorders in ASD is discussed, and the state of treatment research for co-occurring disorders is summarized. This study concludes with a summary of the extant literature, as well as recommendations for future research.

Planning and Problem solving Using the Five disc Tower of London Task

This paper investigates the planning and problem-solving abilities of normal adult subjects using a complex version of Shallice's (1982, 1988) Tower of London (TOL) task. Subjects were required to plan a fluent solution to a range of 5-disc TOL puzzles and then execute their formulated plans as fast as possible. The number of errors and the times taken to prepare the most efficient solutions increased monotonically with the number of chunks of subgoal moves. A subgoal move is a move that is essential for the solution of the puzzle, but which does not place a disc into its goal position. A subgoal chunk is a consecutive series of subgoal moves that all transfer discs to and from the same pegs. Furthermore, preparation time was found to be sensitive to a manipulation that increased the number of competing alternative choices, at critical steps in move selection. When subjects planned their action sequences “on-line”, analyses of individual moves and individual move latencies suggested that planning TOL solutions was limited by the difficulty in evaluating and selecting one action (or one subgoal chunk) from the set of competing potential actions at each step in the course of problem solving.

Perceptual Similarity in Autism

People with autism have consistently been found to outperform controls on visuo-spatial tasks such as block design, embedded figures, and visual search tasks. Plaisted, O'Riordan, and others (Bonnel et al., 2003; O'Riordan & Plaisted, 2001; O'Riordan, Plaisted, Driver, & Baron-Cohen, 2001; Plaisted, O'Riordan, & Baron-Cohen, 1998a, 1998b) have suggested that these findings might be explained in terms of reduced perceptual similarity in autism, and that reduced perceptual similarity could also account for the difficulties that people with autism have in making generalizations to novel situations. In this study, high-functioning adults with autism and ability-matched controls performed a low-level categorization task designed to examine perceptual similarity. Results were analysed using standard statistical techniques and modelled using a quantitative model of categorization. This analysis revealed that participants with autism required reliably longer to learn the category structure than did the control group but, contrary to the predictions of the reduced perceptual similarity hypothesis, no evidence was found of more accurate performance by the participants with autism during the generalization stage. Our results suggest that when all participants are attending to the same attributes of an object in the visual domain, people with autism will not display signs of enhanced perceptual similarity.

The Comprehension of Syntactic and Affective Prosody by Adults with Autism Spectrum Disorder Without Accompanying Cognitive Deficits

The present study investigates the comprehension of syntactic and affective prosody in adults with autism spectrum disorder without accompanying cognitive deficits (ASD w/o cognitive deficits) as well as age-, education- and gender-matched unimpaired adults, while processing orally presented sentences. Two experiments were conducted: (a) an on-line sentence completion task containing local subject/object ambiguities and (b) an affective prosody task exploring the comprehension of six emotions. The syntactic prosody task revealed that the experimental group performed similar to the control group on the fillers and the object condition. On the other hand, the ASD w/o cognitive deficits group manifested lower accuracy compared to the unimpaired controls in the subject reading condition, as well as slower reaction times in all conditions. In the affective prosody task, the experimental group performed significantly worse than the controls in the recognition of the emotion of surprise, whereas no differences between the experimental and the control group were attested in the recognition of all other emotions. A positive correlation was found between the two tasks in the ASD w/o cognitive deficits group. Thus, individuals with ASD w/o cognitive deficits face slight difficulties with the decoding of prosody, both the syntactic and the affective one. More specifically, these difficulties are attested in the most difficult conditions, i.e. the subject reading and the emotion of surprise.

The adenosine A2A receptor agonist, CGS 21680, attenuates a probabilistic reversal learning deficit and elevated grooming behavior in BTBR mice

Restricted interests and repetitive behaviors (RRBs) are a defining feature of autism spectrum disorder (ASD). To date there are limited options for treating this core symptomology. Treatments that stimulate adenosine A_2A receptors may represent a promising approach for reducing RRBs in ASD. This is because A_2A receptors are expressed on striatal neurons of the basal ganglia indirect pathway. Under activation of this pathway has been associated with RRBs while activation of A_2A receptors leads to increased activity of the indirect basal ganglia pathway. The present studies investigated whether acute, systemic treatment with CGS21680, an A_2A receptor agonist attenuates elevated self-grooming and a probabilistic reversal learning deficit in the BTBR T+ Itpr3^tf /J (BTBR) mouse model of idiopathic autism. The effects of this treatment were also investigated in C57BL/6J (B6) mice as a comparison strain. Using a spatial reversal learning test with 80/20 probabilistic feedback, comparable to one in which ASD individuals exhibit deficits, CGS 21680 (0.005 and 0.01mg/kg) attenuated a reversal learning deficit in BTBR mice. Enhancement in probabilistic reversal learning performance resulted from CGS 21680 improving the consistent maintenance of new adaptive behavioral choice patterns after reversal. CGS 21680 at 0.01 mg, but not 0.005 mg, also reduced self-grooming behavior in BTBR mice. CGS 21680 did not affect self-grooming or reversal learning in B6 mice. These findings demonstrate that A_2A receptor agonists may be a promising receptor target in the treatment of RRBs in ASD. Autism Res 2018, 11: 223-233. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

The present experiments determined whether the drug, CGS 21680, that facilitates activation of adenosine A_2A receptors in the brain, would reduce repetitive and inflexible behaviors in the BTBR mouse model of idiopathic autism. CGS 21680 treatment in BTBR mice reduced repetitive and inflexible behaviors. In the control C57BL/6J (B6) mouse strain, CGS 21680 did not affect performance. These findings suggest that stimulation of brain adenosine A_2A receptors may be a promising therapeutic strategy in ASD.

Examining Discrepancy between Performance on Traditional Measures and Parent Report Measure of Executive Functioning in Autism Spectrum Disorder

There is a growing concern amongst the researchers regarding the ecological validity of the neuropsychological tests used to assess EF in ASD. Traditional EF tests have been criticized for not being unable to tap real-life scenarios that are relevant to and representative of everyday behavior. The present study aimed to examine any potential discrepancy between performance on traditional measures of executive function and behavioural expressions of EF in case of an individual with High Functioning Autism (HFA). The findings highlight the importance of use of ecologically valid measures to gain a more valid assessment of executive functions.

Brief Report: Testing the Impairment of Initiation Processes Hypothesis in Autism Spectrum Disorder

In the present study we aim at providing further evidences for the validity of an initiation processes impairment in autism spectrum disorder (ASD). We applied different verbal fluency tasks designed to decrease or enhance this limitation. A group of high-functioning individuals with ASD and a group of typically developed individuals matched for -age, -IQ and -education, were tested in three verbal fluency tasks. In task 1, we replicated previous findings of an initiation impairment. In tasks 2 and 3, with simple manipulations, we observed that the differences between the groups were respectively eliminated or enhanced. We have not only provided further evidence of impairments in the initiation of a response, but we remarkably show how to circumvent them.

Nonverbal Executive Function is Mediated by Language: A Study of Deaf and Hearing Children

Studies have suggested that language and executive function (EF) are strongly associated. Indeed, the two are difficult to separate, and it is particularly difficult to determine whether one skill is more dependent on the other. Deafness provides a unique opportunity to disentangle these skills because in this case, language difficulties have a sensory not cognitive basis. In this study, deaf (n = 108) and hearing (n = 125) children (age 8 years) were assessed on language and a wide range of nonverbal EF tasks. Deaf children performed significantly less well on EF tasks, even controlling for nonverbal intelligence and speed of processing. Language mediated EF skill, but the reverse pattern was not evident. Findings suggest that language is key to EF performance rather than vice versa.

Cognitive flexibility training intervention among children with autism: a longitudinal study

Autism is defined by persistent deficits in social communication and social interaction in multiple contexts as well as restricted and repetitive patterns of behavior. There are also reported difficulties in the dynamic activation and modification of cognitive processes in response to changes in tasks' demands. Such difficulties are believed to be due to poor flexible cognition. This research aimed to assess and intervene in cognitive flexibility in subjects with autism.Ten subjects diagnosed with autism by psychiatrists, aged 5 years to 13 years and 5 months, were assessed in non-verbal intelligence through Raven's Progressive Matrices in pretest. They were also assessed in cognitive flexibility through Wisconsin Card Sorting Test (WCST) and in patterns of social interactions, behaviors, and communication through Autism Diagnostic Interview-Revised (ADI-R). An intervention program of 14 to 21 sessions was established to enhance cognitive flexibility. In posttest, they were assessed in WCST and ADI-R.All measures of cognitive flexibility improved in posttest except for failure to maintain set. Among the measures improved in posttest, perseverative errors and responses improved in posttest with statistical significance as well as categories completed. Total scores on ADI-R were lower in posttest as well as scores on communication abilities.The qualitative improvement showed by the individuals of this research concerning cognitive flexibility and also patterns of restricted behavior, social interaction, and communication abilities suggests that individuals with autism can benefit from the development of strategies for the enhancement of cognitive flexibility. Nevertheless, more research is suggested with a larger sample among subjects on the autism spectrum.

Working Memory Profiles in HIV-Exposed, Uninfected and HIV-Infected Children: A Comparison with Neurotypical Controls

This study compared the working memory profiles of three groups of children, namely HIV-infected (HIV-I; n = 95), HIV-exposed, uninfected (HIV-EU; n = 86) and an HIV-unexposed, uninfected, (HIV-UU; n = 92) neurotypical control group. Working memory, an executive function, plays an important role in frontal lobe-controlled behaviors, such as motivation, planning, decision making, and social interaction, and is a strong predictor of academic success in school children. Memory impairments have been identified in HIV-I children, particularly in visuospatial processing. Verbal working memory has not been commonly investigated in this population, while it is unknown how the working memory profiles of HIV-EU children compare to their HIV-I and HIV-UU peers. Of interest was whether the working memory profiles of the HIV-EU children would be more similar to the HIV-I group or to the uninfected control group. The results revealed no significant differences in working memory performance between the HIV-I and HIV-EU groups. However, this does not mean that the etiology of the working memory deficits is the same in the two groups, as these groups showed important differences when compared to the control group. In comparison to the controls, the HIV-I group experienced difficulties with processing tasks irrespective of whether they drew on a verbal or visuospatial modality. This appears to stem from a generalized executive function deficit that also interferes with working memory. In the HIV-EU group, difficulties occurred with verbally based tasks, irrespective of whether they required storage or processing. For this group, the dual demands of complex processing and using a second language seem to result in demand exceeding capacity on verbal tasks. Both groups experienced the greatest difficulties with verbal processing tasks for these different reasons. Thus, disruption of different cognitive abilities could result in similar working memory profiles, as evidenced in this study. This has implications for the underlying developmental neurobiology of HIV-I and HIV-EU children, as well the choice of appropriate measures to assist affected children.

Emotional Self-Regulation of Individuals with Autism Spectrum Disorders: Smartwatches for Monitoring and Interaction

In this paper, we analyze the needs of individuals with Autism Spectrum Disorders (ASD) to have a pervasive, feasible and non-stigmatizing form of assistance in their emotional self-regulation, in order to ease certain behavioral issues that undermine their mental health throughout their life. We argue the potential of recent widespread wearables, and more specifically smartwatches, to achieve this goal. Then, a smartwatch system that implements a wide range of self-regulation strategies and infers outburst patterns from physiological signals and movement is presented, along with an authoring tool for smartphones that is to be used by caregivers or family members to create and edit these strategies, in an adaptive way. We conducted an intensive experiment with two individuals with ASD who showed varied, representative behavioral responses to their emotional dysregulation. Both users were able to employ effective, customized emotional self-regulation strategies by means of the system, recovering from the majority of mild stress episodes and temper tantrums experienced in the nine days of experiment in their classroom.

Regional Cerebral Glucose Metabolism and its Association with Phenotype and Cognitive Functioning in Patients with Autism

INTRODUCTION

In spite of three decades of neuroimaging, we are unable to find consistent and coherent anatomical or pathophysiological basis for autism as changes are subtle and there are no studies from India.

AIM

To study the regional cerebral glucose metabolism in children with autism using positron emission tomography (PET) scan and to study the behavior and cognitive functioning among them.

MATERIALS AND METHODS

Ten subjects (8-19 years) meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for autism were evaluated on Childhood Autism Rating Scale (CARS), trail making test (TMT) A and B, Wisconsin card sorting test, Raven's progressive matrices, and PET scan. A control group of 15 matched subjects without any brain pathology or neurological disorder was similarly studied.

RESULTS

Four out of the ten patients with autism had abnormal PET scan findings, and in contrast, none of the patients in the control group had abnormal PET scan. Of the four patients with abnormality in the PET scan, two patients had findings suggestive of hypometabolism in cerebellum bilaterally; one patient showed bilateral hypometabolism in anterior temporal cortices and cerebellum, and the fourth patient had hypermetabolism in the bilateral frontal cortices and medial occipital cortices. Subjects with autism performed poorly on neuropsychological testing. Patients with abnormal PET scan findings had significantly higher scores on the "body use" domain of CARS indicating more stereotypy.

CONCLUSION

Findings of this study support the view of altered brain functioning in subjects with autism.

Internal noise estimates correlate with autistic traits

Previous neuroimaging research has reported increased internal (neural) noise in sensory systems of autistic individuals. However, it is unclear if this difference has behavioural or perceptual consequences, as previous attempts at measuring internal noise in ASD psychophysically have been indirect. Here, we use a "gold standard" psychophysical double-pass paradigm to investigate the relationship between internal noise and autistic traits in the neurotypical population (n = 43). We measured internal noise in three tasks (contrast perception, facial expression intensity perception, and number summation) to estimate a global internal noise factor using principal components analysis. This global internal noise was positively correlated with autistic traits (r_s  = 0.32, P = 0.035). This suggests that increased internal noise is associated with the ASD phenotype even in subclinical populations. The finding is discussed in relation to the neural and genetic basis of internal noise in ASD. Autism Res 2017, 10: 1384-1391. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Planning Skills in Autism Spectrum Disorder Across the Lifespan: A Meta-analysis and Meta-regression

Individuals with an autism spectrum disorder (ASD) are thought to encounter planning difficulties, but experimental research regarding the mastery of planning in ASD is inconsistent. By means of a meta-analysis of 50 planning studies with a combined sample size of 1755 individuals with and 1642 without ASD, we aim to determine whether planning difficulties do exist and which factors contribute to this. Planning problems were evident in individuals with ASD (Hedges'g = 0.52), even when taking publication bias into account (Hedges'g = 0.37). Neither age, nor task-type, nor IQ reduced the observed heterogeneity, suggesting that these were not crucial moderators within the current meta-analysis. However, while we showed that ASD individuals encounter planning difficulties, the bias towards publishing positive findings restricts strong conclusions regarding the role of potential moderators.

Cerebellar contribution to higher and lower order rule learning and cognitive flexibility in mice

Cognitive flexibility has traditionally been considered a frontal lobe function. However, converging evidence suggests involvement of a larger brain circuit which includes the cerebellum. Reciprocal pathways connecting the cerebellum to the prefrontal cortex provide a biological substrate through which the cerebellum may modulate higher cognitive functions, and it has been observed that cognitive inflexibility and cerebellar pathology co-occur in psychiatric disorders (e.g., autism, schizophrenia, addiction). However, the degree to which the cerebellum contributes to distinct forms of cognitive flexibility and rule learning is unknown. We tested lurcher↔wildtype aggregation chimeras which lose 0-100% of cerebellar Purkinje cells during development on a touchscreen-mediated attentional set-shifting task to assess the contribution of the cerebellum to higher and lower order rule learning and cognitive flexibility. Purkinje cells, the sole output of the cerebellar cortex, ranged from 0 to 108,390 in tested mice. Reversal learning and extradimensional set-shifting were impaired in mice with⩾95% Purkinje cell loss. Cognitive deficits were unrelated to motor deficits in ataxic mice. Acquisition of a simple visual discrimination and an attentional-set were unrelated to Purkinje cells. A positive relationship was observed between Purkinje cells and errors when exemplars from a novel, non-relevant dimension were introduced. Collectively, these data suggest that the cerebellum contributes to higher order cognitive flexibility, lower order cognitive flexibility, and attention to novel stimuli, but not the acquisition of higher and lower order rules. These data indicate that the cerebellar pathology observed in psychiatric disorders may underlie deficits involving cognitive flexibility and attention to novel stimuli.

Using inclusive sampling to highlight specific executive functioning impairments in autism spectrum disorder

Objectives: The aim of the study is to help identify the nature of impaired executive functioning (EF) in children with autism spectrum disorder (ASD). It is also argued that participant sampling by age alone should inform experimental research on EF, as selection through IQ matching may weaken any experimental effects. Methods: Sixteen children with ASD across a wide range of Nonverbal IQ (NVIQ) and 16 neurotypical control children matched on age alone were given two different types of computerized sequencing game. Both required top-down organization, but in one case the sequence had to be self-generated while in the second it had to be learned and strictly followed. Measures of learning success in relation to NVIQ, and information processing demands were made. Results: Children with ASD were significantly impaired on the first task only, especially when the processing demands were increased. The effects were particularly pronounced for children with below average NVIQ. Conclusions: The study indicates a selective problem with self-organized sequencing in ASD with implications for certain real world contexts, but also points to a need for more inclusive sampling of children in order to fully expose specific executive impairments in autism spectrum disorder.

Understanding Behavioural Rigidity in Autism Spectrum Conditions: The Role of Intentional Control

Although behavioural rigidity belongs to the core symptoms of autism spectrum conditions, little is known about its underlying cognitive mechanisms. The current study investigated the role of intentional control mechanisms in behavioural rigidity in autism. Autistic individuals and their matched controls were instructed to repeatedly choose between two simple cognitive tasks and to respond accordingly to the subsequently presented stimulus. Results showed that autistic participants chose to repeat tasks more often than their controls and when choosing to switch, they demonstrated larger performance costs. These findings illustrate that when required to make their own choices, autistic people demonstrate rigidity at different performance levels, suggesting that intentional control mechanisms might be important for a better understanding of behavioural rigidity in autism.

The Use of Linguistic Cues in Sentence Comprehension by Mandarin-Speaking Children with High-Functioning Autism

Two studies were conducted to investigate how high-functioning children with autism use different linguistic cues in sentence comprehension. Two types of linguistic cues were investigated: word order and morphosyntactic cues. The results show that children with autism can use both types of cues in sentence comprehension. However, compared to age-matched typically developing peers, children with autism relied significantly more on word order cues and exhibited significantly more difficulties in interpreting sentences in which there was a conflict between the morphosyntactic cue and the word order cue. We attribute the difficulties exhibited by children with autism to their deficits in executive function. We then discuss the implications of the findings for understanding the nature of the sentence processing mechanism in autism.

Emerging Executive Functioning and Motor Development in Infants at High and Low Risk for Autism Spectrum Disorder

Existing evidence suggests executive functioning (EF) deficits may be present in children with autism spectrum disorder (ASD) by 3 years of age. It is less clear when, prior to 3 years, EF deficits may emerge and how EF unfold over time. The contribution of motor skill difficulties to poorer EF in children with ASD has not been systematically studied. We investigated the developmental trajectory of EF in infants at high and low familial risk for ASD (HR and LR) and the potential associations between motor skills, diagnostic group, and EF performance. Participants included 186 HR and 76 LR infants. EF (A-not-B), motor skills (Fine and Gross Motor), and cognitive ability were directly assessed at 12 months and 24 months of age. Participants were directly evaluated for ASD at 24 months using DSM-IV-TR criteria and categorized as HR-ASD, HR-Negative, and LR-Negative. HR-ASD and HR-Negative siblings demonstrated less improvement in EF over time compared to the LR-Negative group. Motor skills were associated with group and EF performance at 12 months. No group differences were found at 12 months, but at 24 months, the HR-ASD and HR-Negative groups performed worse than the LR-Negative group overall after controlling for visual reception and maternal education. On reversal trials, the HR-ASD group performed worse than the LR-Negative group. Motor skills were associated with group and EF performance on reversal trials at 24 months. Findings suggest that HR siblings demonstrate altered EF development and that motor skills may play an important role in this process.

Neuropsychological Profiles of Children with Asperger Syndrome and Autism

This study examined the possibility that diagnostic differentiation between children with autism and Asperger syndrome may be enhanced through the use of neuropsychological profiles. Two groups of children, clinically diagnosed as having Asperger syndrome ( n35) or autism ( n21), were tested with a neuropsychological battery to assess the propositions that these groups might differ in terms of Wechsler IQ profiles, brain hemispheric strengths and weaknesses, and executive functioning. Clinically diagnosed children with Asperger syndrome and autism were not differentiated on the basis of their neuropsychological profiles. The major difference between them was the overall higher IQ in Asperger syndrome, which was largely due to superior verbal abilities. Differences were also examined using DSM-IV/ICD-10 criteria: children were grouped according to the early history of presence or absence of language delay. No differences between the groups on any neurocognitive measure were found and there was no support for current neuropsychological theories purporting to support differential diagnostic status. It appears that current diagnostic differentiation in clinical practice may be primarily influenced by the child’s estimated verbal IQ level.

DSM-IV-Defined Asperger Syndrome: Cognitive, Behavioral and Early History Differentiation from High-Functioning Autism

This study compared 2 3 children with high-functioning autism with 12 children with Asperger syndrome, both defined according to strict DSM-IV diagnostic criteria. The groups were well matched on chronological age, gender and intellectual ability. Three possible sources of difference between Asperger syndrome and highfunctioning autism were examined: cognitive function, current symptomatology and early history. We found few group differences in current presentation and cognitive function, but many early history differences. The Asperger syndrome group generally demonstrated less severe early symptoms, a milder developmental course and better out-come than the high-functioning autism group. Many of the group dif-ferences appeared secondary to the initial group definition process, however. Overall, the results suggest that Asperger syndrome and high-functioning autism involve the same fundamental symptomatology, differing only in degree or severity.

Weak Central Coherence: A Cross-Domain Phenomenon Specific to Autism?

This study investigated whether evidence for the weak central coherence theory could be specifically associated with a group of children with autism compared with normally developing children ( n = 17 per group). Two tasks were employed, one involving visual illusions and the other verbal homophones. Both were based on tasks used in previous central coherence research. Incorporation of tasks involving the use of different domains (verbal versus visual) also enabled the investigation of claims that weak central coherence is a cross-domain processing style or deficit. The autistic group were found to be no different to the control group in performance on the visual illusions task. The autistic group made more errors than the normally developing group on the rare condition of the homophone task. However, analysis suggests this difference is mediated by verbal ability level and not diagnostic status per se. Theoretical implications and alternative explanations are discussed.

Executive Function/Attention Deficits in Boys with Asperger Syndrome, Attention Disorder and Reading/Writing Disorder

Executive function/attention deficits were examined in children with Asperger syndrome, attention disorder and reading/ writing disorder and in a group of normal children. Neuropsychological tests as well as cognitive tasks measuring different components in the processing of information were used. The measures were divided into Mirsky’s four components of attention, namely ‘sustain’,‘focus-execute’,‘shift’ and ‘encode’. All abnormal groups differed markedly from the normal group on measures of executive function/attention. The group diagnosed as having attention disorder showed the most consistent difficulties. However, no specific marker of ‘executive function deficits’ that could represent the three different disorders was found.