A meta-analysis of differences in IQ profiles between individuals with Asperger's disorder and high-functioning autism

Cognitive Profile in Autism and ADHD: A Meta-Analysis of Performance on the WAIS-IV and WISC-V

OBJECTIVE

Previous research has suggested that neurodevelopmental conditions may be associated with distinctive cognitive profiles on the Wechsler intelligence tests (of which the most recent editions are the WAIS-IV and WISC-V). However, the extent to which a cognitive profile can be reliably identified for individuals meeting criteria for autism or ADHD remains unclear. The present review investigated this issue.

METHOD

A search was conducted in PsycInfo, Embase, and Medline in October 2022 for papers reporting the performance of children or adults diagnosed with autism or ADHD on the WAIS-IV or the WISC-V. Test scores were aggregated using meta-analysis.

RESULTS

Scores were analyzed from over 1,800 neurodivergent people reported across 18 data sources. Autistic children and adults performed in the typical range for verbal and nonverbal reasoning, but scored ~1 SD below the mean for processing speed and had slightly reduced scores on working memory. This provides evidence for a "spiky" cognitive profile in autism. Performance of children and adults with ADHD was mostly at age-expected levels, with slightly reduced scores for working memory.

CONCLUSION

Although the pattern of performance on the Wechsler tests is not sufficiently sensitive or specific to use for diagnostic purposes, autism appears to be associated with a cognitive profile of relative strengths in verbal and nonverbal reasoning and a weakness in processing speed. Attention deficit hyperactivity disorder appears less associated with a particular cognitive profile. Autistic individuals may especially benefit from a cognitive assessment to identify and support with their strengths and difficulties.

Genesis, modelling and methodological remedies to autism heterogeneity

Diagnostic criteria used in autism research have undergone a shift towards the inclusion of a larger population, paralleled by increasing, but variable, estimates of autism prevalence across clinical settings and continents. A categorical diagnosis of autism spectrum disorder is now consistent with large variations in language, intelligence, comorbidity, and severity, leading to a heterogeneous sample of individuals, increasingly distant from the initial prototypical descriptions. We review the history of autism diagnosis and subtyping, and the evidence of heterogeneity in autism at the cognitive, neurological, and genetic levels. We describe two strategies to address the problem of heterogeneity: clustering, and truncated-compartmentalized enrollment strategy based on prototype recognition. The advances made using clustering methods have been modest. We present an alternative, new strategy for dissecting autism heterogeneity, emphasizing incorporation of prototypical samples in research cohorts, comparison of subgroups defined by specific ranges of values for the clinical specifiers, and retesting the generality of neurobiological results considered to be acquired from the entire autism spectrum on prototypical cohorts defined by narrow specifiers values.

Autismus: Ein Überblick über Lernvoraussetzungen und Fördermaßnahmen

Zusammenfassung. Autistische Schülerinnen und Schüler besitzen häufig geringere schulische Kompetenzen als nicht-autistische Schülerinnen und Schüler. Zugleich bestehen große Unterschiede in den schulischen Kompetenzen zwischen autistischen Schülerinnen und Schülern. Nicht selten weisen sie schulische Kompetenzen auf, die niedriger sind, als es aufgrund ihrer kognitiven Fähigkeiten zu erwarten wäre. Um zu verstehen, welche Faktoren das Lernen autistischer Schülerinnen und Schüler beeinflussen, wird in diesem Artikel ein Überblick über die Lernvoraussetzungen autistischer Schülerinnen und Schüler gegeben. Der Überblick zeigt, dass es autistischen Schülerinnen und Schülern schwerfallen kann, Vorwissen abzurufen und in Lernsituationen aktiv anzuwenden, Lernprozesse aufgrund von Einschränkungen in den exekutiven Funktionen angemessen zu steuern, verbale und visuelle Informationen im Arbeitsgedächtnis zu verarbeiten, kognitive und metakognitive Lernstrategien spontan anzuwenden, sich mit Lerninhalten auseinanderzusetzen, die nicht ihren eigenen Interessen entsprechen, und lernabträgliche Emotionen mittels geeigneter Strategien zu regulieren. Um autistische Schülerinnen und Schüler im Lernen zu unterstützen, werden Fördermaßnahmen zu den einzelnen Lernvoraussetzungen vorgestellt. Implikationen für Forschung und Praxis werden diskutiert.

The Diagnosis of Autism: From Kanner to DSM-III to DSM-5 and Beyond

In this paper we review the impact of DSM-III and its successors on the field of autism-both in terms of clinical work and research. We summarize the events leading up to the inclusion of autism as a "new" official diagnostic category in DSM-III, the subsequent revisions of the DSM, and the impact of the official recognition of autism on research. We discuss the uses of categorical vs. dimensional approaches and the continuing tensions around broad vs. narrow views of autism. We also note some areas of current controversy and directions for the future.

Are Autistic and Alexithymic Traits Distinct? A Factor-Analytic and Network Approach

Despite the heterogeneity in autism, socioemotional difficulties are often framed as universal. Increasing evidence, however, suggests that socioemotional difficulties may be explained by alexithymia, a distinct yet frequently co-occurring condition. If, as some propose, autistic traits are responsible for socioemotional impairments, then alexithymia may itself be a symptom of autism. We aimed to determine whether alexithymia should be considered a product of autism or regarded as a separate condition. Using factor-analytic and network approaches, we provide evidence that alexithymic and autistic traits are distinct. We argue that: (1) models of socioemotional processing in autism should conceptualise difficulties as intrinsic to alexithymia; and (2) assessment of alexithymia is crucial for diagnosis and personalised interventions.

Seeing the forest and the trees: Disentangling autism phenotypes in the age of DSM-5

This paper, written in honor of Professor Ed Zigler, focuses on some of the themes in developmental disabilities research that were so central to his work. It has now been nearly 80 years since Leo Kanner first identified the prototypic form - early infantile autism - of what is now autism spectrum disorder. In this article we summarize the development of the concept and the important accumulation of knowledge over time that has now led us to the recognition of a broader autism phenotype just as, at the same time, the current official diagnostic system in the USA has narrowed the concept. We also address current controversies regarding autism as the diagnosis is impacted by age and developmental factors, gender, and cultural issues. In parallel to the work on intellectual deficiency and development pioneered by Zigler and his colleagues, we summarize some of the challenges for the years ahead.

The Gap Between Cognition and Adaptive Behavior in Students with Autism Spectrum Disorder: Implications for Social Anxiety and the Moderating Effect of Autism Traits

The gap between cognitive ability and adaptive behavior has been thought to enhance psychopathology among people with autism, particularly among those without intellectual disability. We examined this association by exploring the gap between cognitive understanding of social behavior and socially adaptive behavior, and its impact on social anxiety symptoms, obsessive-compulsive symptoms, and depressive symptoms, among 53 university students with autism (without intellectual disability). A higher cognition-social adaptation discrepancy was associated with more social anxiety, but this effect was moderated by autistic trait (AT) levels; a greater gap was associated with more avoidance symptoms of social anxiety only among students with high AT. Cognitive flexibility and prosocial behavior may mitigate the effects of AT. Potential implications and interventions are discussed.

High-resolution chromosomal microarray analysis for copy-number variations in high-functioning autism reveals large aberration typical for intellectual disability

Copy-number variants (CNVs), in particular rare, small and large ones (< 1% frequency) and those encompassing brain-related genes, have been shown to be associated with neurodevelopmental disorders like autism spectrum disorders (ASDs), attention deficit hyperactivity disorder (ADHD), and intellectual disability (ID). However, the vast majority of CNV findings lack specificity with respect to autistic or developmental-delay phenotypes. Therefore, the aim of the study was to investigate the size and frequency of CNVs in high-functioning ASD (HFA) without ID compared with a random population sample and with published findings in ASD and ID. To investigate the role of CNVs for the "core symptoms" of high-functioning autism, we included in the present exploratory study only patients with HFA without ID. The aim was to test whether HFA have similar large rare (> 1 Mb) CNVs as reported in ASD and ID. We performed high-resolution chromosomal microarray analysis in 108 children and adolescents with HFA without ID. There was no significant difference in the overall number of rare CNVs compared to 124 random population samples. However, patients with HFA carried significantly more frequently CNVs containing brain-related genes. Surprisingly, six HFA patients carried very large CNVs known to be typically present in ID. Our findings provide new evidence that not only small, but also large CNVs affecting several key genes contribute to the genetic etiology/risk of HFA without affecting their intellectual ability.

Recognising autism: a latent transition analysis of parental reports of child autistic spectrum disorder 'red flag' traits before and after age 3

PURPOSE

It has been proposed that parents should be educated about child autistic spectrum disorder (ASD) 'red flag' traits to help professionals identify and address concerning behaviours as early as possible. This study aimed to empirically demonstrate that established/recognised 'red flag' traits in the first 3 years of life would reliably predict ASD risk severity in later childhood, associated with established ASD risk correlates and mirroring functioning diagnostic categories.

METHODS

Using retrospective parental report data from the Mental Health of Children and Young People in Great Britain survey (N = 7977), latent class analysis (LCA) and a quasi -latent transition analysis were used to (1) identify profiles of variation in parent reports of child 'red flag' traits before and after age 3 and (2) model transitions in risk from 3 years and below to ≥ 3 years, respectively, per the 'optimal outcome' model.

RESULTS

Three distinct classes, each characterised by variation in parent 'red flag' trait reporting were identified for the '≤ 3 years of age' and the '≥ 3 years of age' data. Both LCA class profiles comprised groups of children characterised by low, medium and high ASD risk. Dose-response effects for a number of recognised ASD correlates across the low, moderate and high risk '≥ 3 years of age' classes seemed to validate older classes in terms of ASD relevance. Over 54% of children characterised by the highest levels of ASD 'red flag' trait probability at 3 years and below (2% of sample), also populated the high-risk class evidenced in the '≥ 3 years of age' LCA.

CONCLUSIONS

Retrospective parental reports of child ASD 'red flag' traits ≤ 3 years of age were reliable indicators of ASD risk in later childhood.

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.

Subtyping the Autism Spectrum Disorder: Comparison of Children with High Functioning Autism and Asperger Syndrome

Since Hans Asperger's first description (Arch Psych Nervenkrankh 117:76-136, 1944), through Lorna Wing's translation and definition (Psychol Med 11:115-129, 1981), to its introduction in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM, 1994), Asperger Syndrome has always aroused huge interest and debate, until vanishing in the DSM fifth edition (2013). The debate regarded its diagnostic validity and its differentiation from high functioning autism (HFA). The present study aimed to examine whether AS differed from HFA in clinical profiles and to analyze the impact of DSM-5's innovation. Differences in cognitive, language, school functioning and comorbidities, were revealed when 80 AS and 70 HFA patients (3-18 years) were compared. Results suggested that an AS empirical distinction within autism spectrum disorder should be clinically useful.

Visual Encoding of Social Cues Contributes to Moral Reasoning in Autism Spectrum Disorder: An Eye-Tracking Study

Eye-tracking studies suggest that visual encoding is important for social processes such as socio-moral reasoning. Alterations to the visual encoding of faces, for example, have been linked to the social phenotype of autism spectrum disorders (ASDs) and are associated with social and communication impairments. Yet, people with ASD often perform similarly to neurotypical participants on measures of moral reasoning, supporting the hypothesis of differential mechanisms of moral reasoning in ASD. The objective of this study was to document visual encoding and moral reasoning in ASD and neurotypical individuals using a visual, ecological, sociomoral reasoning paradigm paired with eye-tracking. Two groups (ASD, Control) matched for age and IQ completed the SoMoral task, a set of picture situations describing everyday moral dilemmas, while their eye movements and pupil dilation were recorded. Moral understanding, decision-making, and justification were recorded. Participants with ASD presented a longer time to first fixation on faces. They also understood fewer dilemmas and produced fewer socially adaptive responses. Despite a similar average level of moral maturity, the justifications produced by participants with ASD were not distributed in the same way as the neurotypical participants. Visual encoding was a significant predictor of moral decision-making and moral justification for both groups. The results are discussed in the context of alternative mechanisms of moral reasoning in ASD.

Gyrification changes are related to cognitive strengths in autism

Background

Behavioral, cognitive and functional particularities in autism differ according to autism subgroups and might be associated with domain-specific cognitive strengths. It is unknown whether structural changes support this specialization. We investigated the link between cortical folding, its maturation and cognitive strengths in autism subgroups presenting verbal or visuo-spatial peaks of abilities.

Methods

We measured gyrification, a structural index related to function, in 55 autistic participants with (AS-SOD, N = 27) or without (AS-NoSOD, N = 28) a speech onset delay (SOD) with similar symptom severity but respectively perceptual and verbal cognitive strengths, and 37 typical adolescents and young adults matched for intelligence and age. We calculated the local Gyrification Index (lGI) throughout an occipito-temporal region of interest and independently modeled age and peak of ability effects for each group.

Results

Unique gyrification features in both autistic groups were detected in localized clusters. When comparing the three groups, gyrification was found lower in AS-SOD in a fusiform visual area, whereas it was higher in AS-NoSOD in a temporal language-related region. These particular areas presented age-related gyrification differences reflecting contrasting local maturation pathways in AS. As expected, peaks of ability were found in a verbal subtest for the AS-NoSOD group and in the Block Design IQ subtest for the AS-SOD group.

Conclusions

Irrespective of their direction, regional gyrification differences in visual and language processing areas respectively reflect AS-SOD perceptual and AS-NoSOD language-oriented peaks. Unique regional maturation trajectories in the autistic brain may underline specific cognitive strengths, which are key variables for understanding heterogeneity in autism.

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Subgrouping the autism spectrum (AS) partly accounts for its heterogeneity.

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AS individuals with a speech onset delay (SOD) show perceptual cognitive strengths.

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AS individuals without a SOD show language-related cognitive strengths.

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AS subgroups show unique gyrification patterns in areas related to their strengths.

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Cortical structural maturation may be related to domain-specific strengths in AS.

Violent Fantasies in Young Men With Autism Spectrum Disorders: Dangerous or Miserable Misfits? Duty to Protect Whom?

Predictability of dangerousness in association with mental disorders remains elusive, outside of a few relatively well-established risk factors for the prognostication of violence, such as male sex, the presence of a psychotic disorder, and comorbid substance abuse. In clinical practice, inquiry into the presence of aggressive or violent ideation, in the form of ideas of homicide or suicide, is part of a standard mental status examination. Nonetheless, fantasy life, when it concerns harm toward others, may not be as reliable an indicator of imminent danger as it may be in the case of self-harm. Five cases of young Italian men with Asperger syndrome and recurrent and extremely violent femicide fantasies are presented. While there is no direct correlation between autism spectrum conditions and violence, as other humans, persons with an autistic condition are capable of committing crimes, including homicide. All five had in common a number of characteristics and behaviors felt to be pathoplastic: All had been bullied, all had been romantically rejected, all were long-standing First Person Shooter (FPS) game players, and all were avid violent pornography consumers. The potential for an actual neurocognitive impact of violent video games, well documented in the literature, and its combination with personal life history and chronic habituation following long-standing violent pornography use is discussed in the context of social and emotional vulnerabilities. While aggressive fantasies cannot and should not be underestimated, in countries where duty to protect legislation does not exist, a clinical approach is imperative, as, incidentally, should be anywhere.

Role of Two Types of Syntactic Embedding in Belief Attribution in Adults with or without Asperger Syndrome

The role of syntax in belief attribution (BA) is not completely understood in healthy adults and understudied in adults with autism spectrum disorder. Embedded syntax could be useful either for the development of Theory of Mind (ToM) (Emergence account) or more generally over the lifespan (Reasoning account). Two hypotheses have been explored, one suggesting that embedding itself (Relatives and Complement sentences and Metarepresentation account) is important for ToM and another one considering that the embedding of a false proposition into a true one (Complement sentences and Misrepresentation account) is important. The goals of this study were to evaluate (1) the role of syntax in ToM (Emergence vs. Reasoning account), (2) the type of syntax implied in ToM (Metarepresentation vs. Misrepresentation account), and (3) the verbally mediated strategies which compensate for ToM deficits in adults with Asperger Syndrome (AS). Fifty NeuroTypical (NT) adults and 22 adults with AS were involved in a forced-choice task including ±ToM tasks (BA and a control task, physical causation, PC) under four Interference conditions (silence, syllable repetition, relative sentences repetition, and complement sentences repetition). The non-significant ±ToM × Interference interaction effect in the NT group did not support the Reasoning account and thus suggests that syntax is useful only for ToM development (i.e., Emergence account). Results also indicated that repeating complement clauses put NT participants in a dual task whereas repeating relative clauses did not, suggesting that repeating relatives is easier for NT than repeating complements. This could be an argument in favor of the Misrepresentation account. However, this result should be interpreted with caution because our results did not support the Reasoning account. Moreover, AS participants (but not NT participants) were more disrupted by ±ToM tasks when asked to repeat complement sentences compared to relative clause sentences. This result is in favor of the Misrepresentation account and indirectly suggests verbally mediated strategies for ToM in AS. To summarize, our results are in favor of the Emergence account in NT and of Reasoning and Misrepresentation accounts in adults with AS. Overall, this suggests that adults with AS use complement syntax to compensate for ToM deficits.

Narratives of children with high-functioning autism spectrum disorder: A meta-analysis

BACKGROUND

The aim of this meta-analysis was to analyze the narrative performance of children and adolescents with high-functioning Autism Spectrum Disorders (ASD) in terms of microstructure, macrostructure and internal state language.

METHOD

A systematic literature search yielded 24 studies that met the predetermined inclusion criteria. Effect sizes for each study were calculated for eight variables and analyzed using a random effects model. Intellectual ability, age and type of narrative were considered as potential moderators.

RESULTS

Results revealed that the children with ASD performed significantly worse than their peers on all the variables considered.

CONCLUSIONS

Findings are discussed taking into account the main explanatory psychological autism theories. Implications for intervention and orientations for future research are suggested.

From High Intellectual Potential to Asperger Syndrome: Evidence for Differences and a Fundamental Overlap-A Systematic Review

Background: An increasing number of clinicians point to similar clinical features between some children with High Intellectual Potential (HIP or "Giftedness" = Total IQ > 2 SD), and children with Autism Spectrum Disorder (ASD) without intellectual or language delay, formerly diagnosed with Asperger Syndrome. Some of these common features are social interaction impairments, special interests, and in some cases high-verbal abilities. The aim of this article is to determine whether these similarities exist at more fundamental levels, other than clinical, and to explore the literature in order to provide empirical support for an overlap between ASD and HIP. Method: First, comparative studies between ASD and HIP children were sought. Because of a lack of data, the respective characteristics of ASD and HIP subjects were explored by a cross-sectional review of different areas of research. Emphasis was placed on psychometric and cognitive evaluations, experimental and developmental assessments, and neurobiological research, following a "bottom-up" procedure. Results: This review highlights the existence of similarities in the neurocognitive, developmental and neurobiological domains between these profiles, which require further study. In addition, the conclusions of several studies show that there are differences between HIP children with a homogeneous Intellectual Quotient profile and children with a heterogeneous Intellectual Quotient profile. Conclusion: HIP seems to cover different developmental profiles, one of which might share features with ASD. A new line of investigation providing a possible starting-point for future research is proposed. Its implications, interesting from both clinical and research perspectives, are discussed.

A Concise History of Asperger Syndrome: The Short Reign of a Troublesome Diagnosis

First described in 1944 by Hans Asperger (1944), it was not before 1994 that Asperger Syndrome (AS) was included in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, only to disappear in the Manual's fifth edition in 2013. During its brief existence as a diagnostic entity, AS aroused immense interest and controversy. Similar to patients with autism, AS patients show deficits in social interaction, inappropriate communication skills, and interest restriction, but also display a rich variety of subtle clinical characteristics that for many distinguish AS from autism. However, difficulties operationalising diagnostic criteria and differentiating AS from autism ultimately led to its merging into the unifying category of Autistic Spectrum Disorders. Here we briefly review the short history of this fascinating condition.

Down-regulation of a signaling mediator in association with lowered plasma arachidonic acid levels in individuals with autism spectrum disorders

Previous studies have indicated that the altered composition of polyunsaturated fatty acids (PUFAs) might contribute to the pathophysiology of autism spectrum disorder (ASD). We examined the relationship between the plasma fatty acid levels, expressed as μg/ml, and the plasma levels of biomarkers of AA-related signaling mediators, such as ceruloplasmin, transferrin and superoxide dismutase, and assessed the behavioral symptoms of 30 individuals with ASD (mean age, 13.6 ± 4.3 years old) compared with 20 age- and gender-matched normal controls (mean age, 13.2 ± 5.4 years old) using Aberrant Behavior Checklists (ABC). The plasma levels of EPA and the plasma ratios of EPA/AA were significantly higher, while the plasma levels of AA and metabolites, such as 5,8,11,14-eicosatetraenoic acid, adrenic acid, and ceruloplasmin (Cp), were significantly lower in the 30 individuals with ASD compared with the 20 normal controls. The ABC scores were significantly increased in the ASD group compared with those of the control group. Thus, the results of the present study revealed that reduced plasma levels of AA and metabolites in association with high plasma EPA/AA ratios might down-regulate AA-related signaling mediators, such as Cp. Subsequently, reduced plasma Cp levels might reduce the protective capacity for brain damage, resulting in the pathophysiology underlying the behavioral symptoms in individuals with ASD. These findings suggest that reduced plasma AA levels may downregulate Cp.

Speech acquisition predicts regions of enhanced cortical response to auditory stimulation in autism spectrum individuals

A continuum of phenotypes makes up the autism spectrum (AS). In particular, individuals show large differences in language acquisition, ranging from precocious speech to severe speech onset delay. However, the neurological origin of this heterogeneity remains unknown. Here, we sought to determine whether AS individuals differing in speech acquisition show different cortical responses to auditory stimulation and morphometric brain differences. Whole-brain activity following exposure to non-social sounds was investigated. Individuals in the AS were classified according to the presence or absence of Speech Onset Delay (AS-SOD and AS-NoSOD, respectively) and were compared with IQ-matched typically developing individuals (TYP). AS-NoSOD participants displayed greater task-related activity than TYP in the inferior frontal gyrus and peri-auditory middle and superior temporal gyri, which are associated with language processing. Conversely, the AS-SOD group only showed enhanced activity in the vicinity of the auditory cortex. We detected no differences in brain structure between groups. This is the first study to demonstrate the existence of differences in functional brain activity between AS individuals divided according to their pattern of speech development. These findings support the Trigger-threshold-target model and indicate that the occurrence of speech onset delay in AS individuals depends on the location of cortical functional reallocation, which favors perception in AS-SOD and language in AS-NoSOD.

Relationship Between Surface-Based Brain Morphometric Measures and Intelligence in Autism Spectrum Disorders: Influence of History of Language Delay

Autism spectrum disorders (ASD) are a group of conditions that show abnormalities in the neuroanatomy of multiple brain regions. The variability in the development of intelligence and language among individuals on the autism spectrum has long been acknowledged, but it remains unknown whether these differences impact on the neuropathology of ASD. In this study, we aimed to compare associations between surface-based regional brain measures and general intelligence (IQ) scores in ASD individuals with and without a history of language delay. We included 64 ASD adults of normal intelligence (37 without a history of language delay and 27 with a history of language delay and 80 neurotypicals). Regions with a significant association between verbal and nonverbal IQ and measures of cortical thickness (CT), surface area, and cortical volume were first identified in the combined sample of individuals with ASD and controls. Thicker dorsal frontal and temporal cortices, and thinner lateral orbital frontal and parieto-occipital cortices were associated with greater and lower verbal IQ scores, respectively. Correlations between cortical volume and verbal IQ were observed in similar regions as revealed by the CT analysis. A significant difference between ASD individuals with and without a history of language delay in the association between CT and verbal IQ was evident in the parieto-occipital region. These results indicate that ASD subgroups defined on the basis of differential language trajectories in childhood can have different associations between verbal IQ and brain measures in adulthood despite achieving similar levels of cognitive performance.

Developmental white matter microstructure in autism phenotype and corresponding endophenotype during adolescence

During adolescence, white matter microstructure undergoes an important stage of development. It is hypothesized that the alterations of brain connectivity that have a key role in autism spectrum conditions (ASCs) may interact with the development of white matter microstructure. This interaction may be present beyond the phenotype of autism in siblings of individuals with ASC, who are 10 to 20 times more likely to develop certain forms of ASC. We use diffusion tensor imaging to examine how white matter microstructure measurements correlate with age in typically developing individuals, and how this correlation differs in n=43 adolescents with ASC and their n=38 siblings. Correlations observed in n=40 typically developing individuals match developmental changes noted in previous longitudinal studies. In comparison, individuals with ASC display weaker negative correlation between age and mean diffusivity in a broad area centred in the right superior longitudinal fasciculus. These differences may be caused either by increased heterogeneity in ASC or by temporal alterations in the group's developmental pattern. Siblings of individuals with ASC also show diminished negative correlation between age and one component of mean diffusivity-second diffusion eigenvalue-in the right superior longitudinal fasciculus. As the observed differences match for location and correlation directionality in our comparison of typically developing individuals to those with ASC and their siblings, we propose that these alterations constitute a part of the endophenotype of autism.

[High-functioning autism spectrum disorders in adulthood]

The prevalence of autism spectrum disorders in the general population is approximately 1 %. Some individuals with high-functioning autism graduate from regular schools without autism having been diagnosed and problems only occur when the demands for social competence increase. Then patients often present with secondary psychiatric symptoms, such as depression, anxiety or interpersonal problems. At this time, typical autistic features, such as social interaction deficits, restricted interests and stereotypic behavior can be camouflaged by high compensatory skills, particularly in highly intelligent patients. Therefore, missed or wrong diagnoses are frequent. Interviews, questionnaires and neuropsychological tests might be used to support the diagnosis. In cases where there is evidence for a secondary cause of autistic symptoms, somatic disorders should be excluded. Pharmacological treatment should be symptom-oriented. Individualized psychotherapeutic approaches are becoming increasingly more available; however, pragmatic solutions often need to be deployed.