Defining the cognitive phenotype of autism

Severe mood problems in adolescents with autism spectrum disorder

INTRODUCTION

Severe mood dysregulation and problems (SMP) in otherwise typically developing youth are recognized as an important mental health problem with a distinct set of clinical features, family history and neurocognitive characteristics. SMP in people with autism spectrum disorders (ASDs) have not previously been explored.

METHOD

We studied a longitudinal, population-based cohort of adolescents with ASD in which we collected parent-reported symptoms of SMP that included rage, low and labile mood and depressive thoughts. Ninety-one adolescents with ASD provided data at age 16 years, of whom 79 had additional data from age 12. We studied whether SMP have similar correlates to those seen in typically developing youth.

RESULTS

Severe mood problems were associated with current (parent-rated) and earlier (parent- and teacher-rated) emotional problems. The number of prior psychiatric diagnoses increased the risk of subsequent SMP. Intellectual ability and adaptive functioning did not predict to SMP. Maternal mental health problems rated at 12 and 16 years were associated with SMP. Autism severity as rated by parents was associated with SMP, but the relationship did not hold for clinician ratings of autistic symptoms or diagnosis. SMP were associated with difficulty in identifying the facial expression of surprise, but not with performance recognizing other emotions. Relationships between SMP and tests of executive function (card sort and trail making) were not significant after controlling for IQ.

CONCLUSIONS

This is the first study of the behavioural and cognitive correlates of severe mood problems in ASD. As in typically developing youth, SMP in adolescents with ASD are related to other affective symptoms and maternal mental health problems. Previously reported links to deficits in emotion recognition and cognitive flexibility were not found in the current sample. Further research is warranted using categorical and validated measures of SMP.

Cognition in males and females with autism: similarities and differences

The male bias in autism spectrum conditions (ASC) has led to females with ASC being under-researched. This lack of attention to females could hide variability due to sex that may explain some of the heterogeneity within ASC. In this study we investigate four key cognitive domains (mentalizing and emotion perception, executive function, perceptual attention to detail, and motor function) in ASC, to test for similarities and differences between males and females with and without ASC (n = 128 adults; n = 32 per group). In the mentalizing and facial emotion perception domain, males and females with ASC showed similar deficits compared to neurotypical controls. However, in attention to detail and dexterity involving executive function, although males with ASC showed poorer performance relative to neurotypical males, females with ASC performed comparably to neurotypical females. We conclude that performance in the social-cognitive domain is equally impaired in male and female adults with ASC. However, in specific non-social cognitive domains, performance within ASC depends on sex. This suggests that in specific domains, cognitive profiles in ASC are modulated by sex.

Annual research review: re-thinking the classification of autism spectrum disorders

BACKGROUND

The nosology of autism spectrum disorders (ASD) is at a critical point in history as the field seeks to better define dimensions of social-communication deficits and restricted/repetitive behaviors on an individual level for both clinical and neurobiological purposes. These different dimensions also suggest an increasing need for quantitative measures that accurately map their differences, independent of developmental factors such as age, language level and IQ.

METHOD

Psychometric measures, clinical observation as well as genetic, neurobiological and physiological research from toddlers, children and adults with ASD are reviewed.

RESULTS

The question of how to conceptualize ASDs along dimensions versus categories is discussed within the nosology of autism and the proposed changes to the DSM-5 and ICD-11. Differences across development are incorporated into the new classification frameworks.

CONCLUSIONS

It is crucial to balance the needs of clinical practice in ASD diagnostic systems, with neurobiologically based theories that address the associations between social-communication and restricted/repetitive dimensions in individuals. Clarifying terminology, improving description of the core features of ASD and other dimensions that interact with them and providing more valid and reliable ways to quantify them, both for research and clinical purposes, will move forward both practice and science.

Ageing in people with autistic spectrum disorder

BACKGROUND

Although autism in children and in adults attracts attention with respect to clinical and research needs, autism in the older individuals has not been considered to any degree. We review the evidence for urgently addressing the question of ageing in people with autistic spectrum disorder (ASD), focusing on those with disability.

METHODS

Perspectives are reviewed in relation to demographics, experiences of relatives or carers, anticipated residential care needs, requirement for specifically designed cognitive assessment tools and importance of initiating new brain ageing research initiatives in this area.

RESULTS

With escalating numbers of ASD individuals with disability reaching old age, provision of care is the paramount issue that is only beginning to be addressed in a few European communities and in the USA. How ageing affects cognition in such individuals as they reach an age no longer consistent with parental care is unknown, lacking any published evidence, and there is a clear need to design cognitive and behavioural assessment tools appropriate to ageing in ASD individuals with disability, as was the case with respect to dementia as a whole. Although there is a growing body of evidence on pathological, imaging, neuropharmacological and other key brain abnormalities in ASD, these are, to date, confined to children and young (only rarely to middle aged) adults.

CONCLUSIONS

The need for new initiatives in research into ageing in ASD is urgent. Apart from a growing care crisis, the prospect of understanding brain ageing in this population may bring potential rewards beyond immediate clinical need given the precedent of Down syndrome.

Testing the construct validity of proposed criteria for DSM-5 autism spectrum disorder

OBJECTIVE

To use confirmatory factor analysis to test the construct validity of the proposed DSM-5 symptom model of autism spectrum disorder (ASD), in comparison to alternative models, including that described in DSM-IV-TR.

METHOD

Participants were 708 verbal children and young persons (mean age, 9.5 years) with mild to severe autistic difficulties. Autistic symptoms were measured using the Developmental, Dimensional and Diagnostic interview (3Di). The fit of the two-factor DSM-5 model, which has a social communication and a restricted, repetitive behavior (RRB) factor, was compared with that of alternative models. In one half of the sample, properties of the DSM-5 model were examined to investigate the validity of specific diagnostic criteria, informing the development of a better fitting DSM-5 model. This was then cross-validated in the remaining "hold-out" half of the sample; and its stability was tested across groups defined by age, sex, and symptom severity.

RESULTS

The DSM-5 model was superior to the three-factor DSM-IV-TR model. It was improved by the removal of items measuring "play and imagination" and "stereotyped and repetitive use of language." A scale measuring sensory abnormalities was added to the model, and loaded onto its RRB factor. This DSM-5 model fit well in the hold-out sample; was stable across age and sex; and fit adequately in those with clinical and sub-threshold autistic presentations.

CONCLUSIONS

Among higher-functioning individuals, ASD is a dyad, not a triad, with distinct social communication and repetitive behavior dimensions. As suggested in the proposed DSM-5 criteria, sensory abnormalities are part of the RRB symptom cluster.

Genetics of autism spectrum disorders

Characterized by a combination of abnormalities in language, social cognition and mental flexibility, autism is not a single disorder but a neurodevelopmental syndrome commonly referred to as autism spectrum disorder (ASD). Several dozen ASD susceptibility genes have been identified in the past decade, collectively accounting for 10-20% of ASD cases. These findings, although demonstrating that ASD is etiologically heterogeneous, provide important clues about its pathophysiology. Diverse genetic and genomic approaches provide evidence converging on disruption of key biological pathways, many of which are also implicated in other allied neurodevelopmental disorders. Knowing the genes involved in ASD provides us with a crucial tool to probe both the specificity of ASD and the shared neurobiological and cognitive features across what are considered clinically distinct disorders, with the goal of linking gene to brain circuits to cognitive function.

No evidence for a fundamental visual motion processing deficit in adolescents with autism spectrum disorders

It has been suggested that atypicalities in low-level visual processing contribute to the expression and development of the unusual cognitive and behavioral profile seen in autism spectrum disorders (ASD). However, previous investigations have yielded mixed results. In the largest study of its kind (ASD n = 89; non-ASD = 52; mean age 15 years 6 months) and testing across the spectrum of IQ (range 52-133), we investigated performance on three measures of basic visual processing: motion coherence, form-from-motion and biological motion (BM). At the group level, we found no evidence of differences between the two groups on any of the tasks, suggesting that there is no fundamental visual motion processing deficit in individuals with an ASD, at least by adolescence. However, we identified a tail of individuals with ASD (18% of the sample) who had exceptionally poor BM processing abilities compared to the non-ASD group, and who were characterized by low IQ. For the entire sample of those both with and without ASD, performance on the BM task uniquely correlated with performance on the Frith-Happé animations, a higher-level task that demands the interpretation of moving, interacting agents in order to understand mental states. We hypothesize that this association reflects the shared social-cognitive characteristics of the two tasks, which have a common neural underpinning in the superior temporal sulcus.