Attention profiles in autism spectrum disorder and subtypes of attention-deficit/hyperactivity disorder

Comparing Executive Functions in Children and Adolescents with Autism and ADHD-A Systematic Review and Meta-Analysis

Two neurodevelopmental conditions, autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), have been associated with executive function (EF) impairments but the specificity of their impairments is still controversial. The present meta-analysis aimed to identify the differences in EF profiles of ASD, ADHD, and ASD+ADHD in relation to a control group of individuals with typical development (TD) and to understand whether the EF performance could change depending upon the type of measure used to assess EF (performance tests vs. questionnaires). Results from 36 eligible studies revealed that ADHD and ASD showed more difficulties than the TD group in tests and, particularly, in questionnaires. No significant differences in the EF profile emerged between ASD and ADHD when assessed through neuropsychological tests (d = 0.02), while significant differences emerged when assessed through questionnaires, with ADHD having higher ratings than ASD (d = -0.34). EF questionnaires and neuropsychological tests may catch two different constructs of EF, with the former being more predictive of everyday life EF impairments. The comparison between the double diagnosis group (ADHD+ASD) and the clinical groups pointed out that the former has a more similar EF profile to the ADHD-alone one and that it shows more difficulties than ASD-alone.

Intrinsic network abnormalities in children with autism spectrum disorder: an independent component analysis

Aberrant intrinsic brain networks are consistently observed in individuals with autism spectrum disorder. However, studies examining the strength of functional connectivity across brain regions have yielded conflicting results. Therefore, this study aimed to investigate the functional connectivity of the resting brain in children with low-functioning autism, including during the early developmental stages. We explored the functional connectivity of 43 children with autism spectrum disorder and 54 children with typical development aged 2 to 12 years using resting-state functional magnetic resonance imaging data. We used independent component analysis to classify the brain regions into six intrinsic networks and analyzed the functional connectivity within each network. Moreover, we analyzed the relationship between functional connectivity and clinical scores. In children with autism, the under-connectivities were observed within several brain networks, including the cognitive control, default mode, visual, and somatomotor networks. In contrast, we found over-connectivities between the subcortical, visual, and somatomotor networks in children with autism compared with children with typical development. Moderate effect sizes were observed in entire networks (Cohen's d = 0.43-0.77). These network alterations were significantly correlated with clinical scores such as the communication sub-score (r = - 0.442, p = 0.045) and the calibrated severity score (r = - 0.435, p = 0.049) of the Autism Diagnostic Observation Schedule. These opposing results observed based on the brain areas suggest that aberrant neurodevelopment proceeds in various ways depending on the functional brain regions in individuals with autism spectrum disorder.

The role of stimulant washout status in functional connectivity of default mode and fronto-parietal networks in children with neurodevelopmental conditions

BACKGROUND

Stimulant medication is the primary pharmacological treatment for attention dysregulation and is commonly prescribed for children with Attention-Deficit/Hyperactivity Disorder (ADHD) and Autism. Neuroimaging studies of these groups commonly use a 24-48-hour washout period to mediate the effects of stimulant medication on functional connectivity (FC) metrics. However, the impact of washout on functional connectivity has received limited study.

METHODS

We used fMRI data from participants with diagnosis of Autism and ADHD (and an off stimulant control) from the Adolescent Brain and Cognitive Development (ABCD) and Autism Brain Imaging Data Exchange (ABIDE) databases to explore the effect of simulant washout on FC. Connectivity within and between the default mode (DMN) and fronto-parietal networks (FPN) was examined, as these networks have previously been implicated in attention dysregulation and associated with stimulant medication usage. For each diagnostic group, we assessed effects in interconnectivity between DMN and FPN, intraconnectivity within DMN, and intraconnectivity within FPN.

RESULTS

We found no significant effect of medication status in intra- and inter-connectivity of the DMN and the FPN in either diagnostic group.

IMPLICATIONS

Our findings suggest that more information is needed about the effect of stimulant medication, and washout, on the FC of attention networks in clinical populations.

A bibliometric analysis of autism spectrum disorder signaling pathways research in the past decade

Background

This study employs bibliometric methods to comprehensively understand the fundamental structure of research about Autism Spectrum Disorder (ASD) Signaling Pathways by examining key indicators such as nations, institutions, journals, authors, and keywords.

Methodology

We utilized the WoScc database to retrieve literature relevant to ASD Signaling Pathways published between 2013 and 2023. Through visual analysis and tools like CiteSpace and VosViewer, we explored nations, institutions, journals, authors, and keywords, thereby constructing relevant networks.

Results

26 The study encompasses 1,396 articles, revealing a consistent increase in publications. The United States, China, and Germany are leading nations in this literature. Regarding research institutions, the University of California system and Eric Klann have garnered significant attention due to their substantial contributions to the field of ASD Signaling Pathways. Most relevant research is published in the journal "Molecular Autism." Research interests are concentrated across various themes, including "elevating neuronal β-catenin levels," "Tunisian children," "Fmr1 knockout (KO) mice," "de novo mutations," "autistic children," "local translation," "propionic acid-induced mouse models," "neurosystems," "glucose metabolism," and "neuronal migration." Future research may emphasize exploring aspects such as gut microbiota, genes, stress, maternal immune activation, memory, and neurodevelopmental disorders of ASD.

Conclusion

This study, through bibliometric analysis of key indicators such as nations, institutions, journals, authors, and keywords, provides a comprehensive overview of the current state of research on ASD Signaling Pathways. These investigations predominantly focus on molecular mechanisms, animal model studies, population-based research, and the structure and function of neurosystems. Future research directions are also clearly proposed. First, in-depth research on the genes and neurodevelopmental disorders associated with ASD will continue to reveal the genetic basis and provide support for precise treatments. At the same time, attention to the gut microbiota will help explore its association with ASD, which may provide clues for new treatments. In addition, the relationship between stress and ASD will become the focus of research to understand better the emotional and behavioral characteristics of ASD patients in stressful situations. Maternal immune activation will also be further studied to explore how environmental factors influence the risk and development of ASD. Finally, a deeper understanding of the cognitive functions of patients with ASD, especially memory and learning, will help develop individualized treatment strategies to improve patients' quality of life. These directions will work together and are expected to provide a more comprehensive understanding of Signaling Pathways research in ASD and provide new ideas and opportunities for future intervention and treatment.

Polygenic risk for ADHD and ASD and their relation with cognitive measures in school children

BACKGROUND

Attention deficit and hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are child-onset neurodevelopmental disorders frequently accompanied by cognitive difficulties. In the current study, we aim to examine the genetic overlap between ADHD and ASD and cognitive measures of working memory (WM) and attention performance among schoolchildren using a polygenic risk approach.

METHODS

A total of 1667 children from a population-based cohort aged 7-11 years with data available on genetics and cognition were included in the analyses. Polygenic risk scores (PRS) were calculated for ADHD and ASD using results from the largest GWAS to date (N = 55 374 and N = 46 351, respectively). The cognitive outcomes included verbal and numerical WM and the standard error of hit reaction time (HRTSE) as a measure of attention performance. These outcomes were repeatedly assessed over 1-year period using computerized version of the Attention Network Test and n-back task. Associations were estimated using linear mixed-effects models.

RESULTS

Higher polygenic risk for ADHD was associated with lower WM performance at baseline time but not over time. These findings remained significant after adjusting by multiple testing and excluding individuals with an ADHD diagnosis but were limited to boys. PRS for ASD was only nominally associated with an increased improvement on verbal WM over time, although this association did not survive multiple testing correction. No associations were observed for HRTSE.

CONCLUSIONS

Common genetic variants related to ADHD may contribute to worse WM performance among schoolchildren from the general population but not to the subsequent cognitive-developmental trajectory assessed over 1-year period.

Annual Research Review: The transdiagnostic revolution in neurodevelopmental disorders

Practitioners frequently use diagnostic criteria to identify children with neurodevelopmental disorders and to guide intervention decisions. These criteria also provide the organising framework for much of the research focussing on these disorders. Study design, recruitment, analysis and theory are largely built on the assumption that diagnostic criteria reflect an underlying reality. However, there is growing concern that this assumption may not be a valid and that an alternative transdiagnostic approach may better serve our understanding of this large heterogeneous population of young people. This review draws on important developments over the past decade that have set the stage for much-needed breakthroughs in understanding neurodevelopmental disorders. We evaluate contemporary approaches to study design and recruitment, review the use of data-driven methods to characterise cognition, behaviour and neurobiology, and consider what alternative transdiagnostic models could mean for children and families. This review concludes that an overreliance on ill-fitting diagnostic criteria is impeding progress towards identifying the barriers that children encounter, understanding underpinning mechanisms and finding the best route to supporting them.

Transdiagnostic and sex differences in cognitive profiles of autism spectrum disorder and attention-deficit/hyperactivity disorder

An increasing number of studies have shown that autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) share symptoms and aetiologies. However, transdiagnostic comparisons between ASD and ADHD is complicated due to the sex differences within each condition. To clarify the similarities and differences in the cognitive functioning between ASD and ADHD, while considering potential sex differences, this study compared cognitive profiles assessed by the WAIS-III between the four groups created by orthogonally combining diagnosis and sex based on the data from 277 ASD males, 86 ASD females, 99 ADHD males and 64 ADHD females. The analysis revealed three major findings. First, performance IQ and perceptual organization index were higher in ADHD males than in ASD males and ADHD females. Second, Gaussian mixture model fitting revealed two clusters underlying the distribution of subindex scores. The percentage of being classified into the cluster that scored lower in all the subindices was higher in females than in males irrespective of diagnosis. Third, feature importance for classification of ASD and ADHD yielded by random forest classifier, a supervised machine learning algorithm, revealed that autism quotient was most informative feature in classifying ASD and ADHD in males, while the discrepancy between verbal and performance intelligence quotient was in females, indicating that the set of behavioral features contributing to classification differs between males and females. Thus, these findings indicate that sex as well as diagnosis is critical in determining the cognitive profiles of people with ASD and ADHD. LAY SUMMARY: The present study compared profiles of cognitive functions measured by Wechsler Adult Intelligence Scale between males and females with ASD and ADHD. The analyses revealed clear sex differences in cognitive functions in both ASD and ADHD and that the set of cognitive functions useful in classifying ASD and ADHD differed between males and females. Thus, biological sex seems to be a critical factor in determining the cognitive profiles of people with ASD and ADHD.

The Synaptic Gene Study: Design and Methodology to Identify Neurocognitive Markers in Phelan-McDermid Syndrome and NRXN1 Deletions

Synaptic gene conditions, i.e., “synaptopathies,” involve disruption to genes expressed at the synapse and account for between 0.5 and 2% of autism cases. They provide a unique entry point to understanding the molecular and biological mechanisms underpinning autism-related phenotypes. Phelan-McDermid Syndrome (PMS, also known as 22q13 deletion syndrome) and NRXN1 deletions (NRXN1ds) are two synaptopathies associated with autism and related neurodevelopmental disorders (NDDs). PMS often incorporates disruption to the SHANK3 gene, implicated in excitatory postsynaptic scaffolding, whereas the NRXN1 gene encodes neurexin-1, a presynaptic cell adhesion protein; both are implicated in trans-synaptic signaling in the brain. Around 70% of individuals with PMS and 43–70% of those with NRXN1ds receive a diagnosis of autism, suggesting that alterations in synaptic development may play a crucial role in explaining the aetiology of autism. However, a substantial amount of heterogeneity exists between conditions. Most individuals with PMS have moderate to profound intellectual disability (ID), while those with NRXN1ds have no ID to severe ID. Speech abnormalities are common to both, although appear more severe in PMS. Very little is currently known about the neurocognitive underpinnings of phenotypic presentations in PMS and NRXN1ds. The Synaptic Gene (SynaG) study adopts a gene-first approach and comprehensively assesses these two syndromic forms of autism. The study compliments preclinical efforts within AIMS-2-TRIALS focused on SHANK3 and NRXN1. The aims of the study are to (1) establish the frequency of autism diagnosis and features in individuals with PMS and NRXN1ds, (2) to compare the clinical profile of PMS, NRXN1ds, and individuals with ‘idiopathic’ autism (iASD), (3) to identify mechanistic biomarkers that may account for autistic features and/or heterogeneity in clinical profiles, and (4) investigate the impact of second or multiple genetic hits on heterogeneity in clinical profiles. In the current paper we describe our methodology for phenotyping the sample and our planned comparisons, with information on the necessary adaptations made during the global COVID-19 pandemic. We also describe the demographics of the data collected thus far, including 25 PMS, 36 NRXN1ds, 33 iASD, and 52 NTD participants, and present an interim analysis of autistic features and adaptive functioning.

Inhibitory Control in Autism Spectrum Disorders: Meta-analyses on Indirect and Direct Measures

This manuscript aimed to advance our understanding of inhibitory control (IC) in autism spectrum disorders (ASD), adopting a meta-analytic multilevel approach. The first meta-analysis, on 164 studies adopting direct measures, indicated a significant small-to-medium (g = 0.484) deficit in the group with ASD (n = 5140) compared with controls (n = 6075). Similar effect sizes between response inhibition and interference control were found, but they were differentially affected by intellectual functioning and age. The second meta-analysis, on 24 studies using indirect measures, revealed a large deficit (g = 1.334) in the group with ASD (n = 985) compared with controls (n = 1300). Presentation format, intellectual functioning, and age were significant moderators. The effect of comorbidity with ADHD was not statistically significant. Implications are discussed for IC research and practice in autism.

Working on Cognitive Functions in a Fully Digitalized Multisensory Interactive Room: A New Approach for Intervention in Autism Spectrum Disorders

The feasibility of working on cognitive functions with children and adults with Autism Spectrum Disorders (ASD) inside Multisensory Interactive Rooms (MIRs) has been poorly investigated, even if sensory atypicalities are common in ASD and usual intervention rooms could represent a challenging sensory setting for patients with ASD. We hypothesized that the possibility to calibrate the sensory stimulation offered by this type of environment, able to promote a positive emotional state in patients with ASD, can consequently favor the interaction with the therapist and the motivation towards activities targeting cognitive functions. High- and low-functioning children and low-functioning adolescents/adults underwent five sessions in a fully digitalized MIR, working on sustained attention, selective attention, association, single inhibition, receptive communication, verbalization, and turn. We developed specific protocols calibrated for sensory stimulation and difficulty level based on the characteristics of the participants. We found statistically significant improvements in all functions, except association, in the children's group. Therefore, a fully digitalized MIR seems suitable for intervention on cognitive functions in ASDs, but further investigations are needed to better address possible differences related to age and functioning level.

ADHD severity as a predictor of cognitive task performance in children with Autism Spectrum Disorder (ASD)

BACKGROUND

In recent years, a number of studies have begun to explore the nature of Attention-Deficit/Hyperactivity Disorder (ADHD) in children with Autism Spectrum Disorder (ASD). In this study, we examined the relationship between both symptoms of ADHD and symptoms of ASD on cognitive task performance in a sample of higher-functioning children and adolescents with ASD. Participants completed cognitive tasks tapping aspects of attention, impulsivity/inhibition, and immediate memory.

AIMS

We hypothesized that children with ASD who had higher levels of ADHD symptom severity would be at higher risk for poorer sustained attention and selective attention, greater impulsivity/disinhibition, and weaker memory.

METHODS AND PROCEDURES

The sample included 92 children (73 males) diagnosed with ASD (Mean Age = 9.41 years; Mean Full Scale IQ = 84.2).

OUTCOMES AND RESULTS

Using regression analyses, more severe ADHD symptomatology was found to be significantly related to weaker performance on tasks measuring attention, immediate memory, and response inhibition. In contrast, increasing severity of ASD symptomatology was not associated with higher risk of poorer performance on any of the cognitive tasks assessed.

CONCLUSIONS AND IMPLICATIONS

These results suggest that children with ASD who have more severe ADHD symptoms are at higher risk for impairments in tasks assessing attention, immediate memory, and response inhibition-similar to ADHD-related impairments seen in the general pediatric population. As such, clinicians should assess various aspects of cognition in pediatric patients with ASD in order to facilitate optimal interventional and educational planning.

Profiles of academic achievement and attention in children with and without Autism Spectrum Disorder

BACKGROUND

Academic outcomes for autistic individuals are heterogeneous, but the reasons for this are unknown. Attention is known to predict learning in typical development, but there is less evidence about this relationship in Autism Spectrum Disorders (ASD), even though attention is reported as atypical in this group.

AIMS

To investigate reading and maths achievement profiles for children with and without an ASD, focusing on the role of attention in these profiles and to enable a better understanding of individual differences.

METHODS

Reading, maths and attention abilities of 22 autistic children (6-16 years) and 59 TD children (6-11 years) were measured using standardised assessments.

RESULTS

A hierarchical cluster analysis that included all children (N = 81) revealed three distinct transdiagnostic subgroups, characterised by children with good, average, and poorer divided attention and academic achievement respectively. Children with poorer attention and achievement displayed relative weaknesses in maths, while children with average or above-average attention and achievement showed no such weakness.

CONCLUSIONS

The findings provide a novel insight into the relationship between attention and achievement and understanding individual differences in ASD and typical development.

Vigilance, Inhibitory Control and Regional Cerebral Blood Oxygenation in the PFC - Differences in ADHD Types of Presentations

It is commonly believed that proven abnormalities in the structure and functioning of the prefrontal lobes affect cognitive deficits in children with ADHD. The purpose of the current study was to assess vigilance, inhibitory control, and regional cerebral blood oxygenation (rCBO2) in the prefrontal cortex (PFC) of children with ADHD. The study included 150 children with ADHD and 51 typically developing (TD) children aged 9-12 years. Children with ADHD showed a deficit in vigilance (assessed by the shortened version of the Mackworth clock task), inhibitory control (the Stroop task), different rCBO2 patterns in the PFC, as well as lower cortical activation during cognitive tasks. These differences are discussed in the context of the types of ADHD presentations.

Attention-Deficit/Hyperactivity Disorder Predominantly Inattentive Subtype/Presentation: Research Progress and Translational Studies

Research on the predominantly inattentive attention-deficit/hyperactivity disorder (ADHD-PI) subtype/presentation is important given its high prevalence, but paradoxically it is under-recognized and undertreated. The temporal stability of the inattention symptom could impact the high worldwide prevalence of ADHD-PI. Some evidence suggests differences in the nature of attentional deficit in ADHD-PI vs. that in other subtypes. Impairments in neuropsychological, neurocognitive, and social functioning are also evident in ADHD-PI, which could be specific to the subtype (e.g., processing speed, social perception, and skills), or differ from others in severity. Neuroimaging studies have also revealed ADHD-PI-specific neuropathological abnormalities and those that are shared with other subtypes. ADHD-PI is highly comorbid with learning and internalizing (e.g., anxiety and depression) disorders. There is no solid evidence for ADHD-PI-specific genetic etiologies and differential responses of subtypes to ADHD medications. Translational studies have used the Wistar Kyoto/NCrl substrain which requires further characterizations as an ADHD-PI model. Overall, ADHD-PI research has been conducted in the context of the Diagnostic and Statistical Manual, which arguably does not conform to the widely recognized "dimensional" view of ADHD. The Research Domain Criteria has been proposed to provide a novel framework for understanding the nature of neuropsychiatric illnesses and ultimately improve their diagnosis and treatment.

Enhancing cognition through pharmacological and environmental interventions: Examples from preclinical models of neurodevelopmental disorders

In this review we discuss the role of environmental and pharmacological treatments to enhance cognition with special regards to neurodevelopmental related disorders and aging. How the environment influences brain structure and function, and the interactions between rearing conditions and gene expression, are fundamental questions that are still poorly understood. We propose a model that can explain some of the discrepancies in findings for effects of environmental enrichment on outcome measures. Evidence of a direct causal correlation of nootropics and treatments that enhanced cognition also will be presented, and possible molecular mechanisms that include neurotrophin signaling and downstream pathways underlying these processes are discussed. Finally we review recent findings achieved with a wide set of behavioral and cognitive tasks that have translational validity to humans, and should be useful for future work on devising appropriate therapies. As will be discussed, the collective findings suggest that a combinational therapeutic approach of environmental enrichment and nootropics could be particularly successful for improving learning and memory in both developmental disorders and normal aging.

Exploring the profiles of children with autism spectrum disorder: association with family factors

This study aimed to identify different profiles of children with autism spectrum disorder (ASD) without intellectual disability (ID) and maternal factors characteristic of these profiles. Participants were 89 children between 7 and 11 years old and their mothers, distributed in two groups, 52 children with ASD and 37 with typical development (TD). Based on the children's adaptive, behavioral, and pragmatic manifestations, three clusters were obtained in the ASD group. Children with the most serious difficulties in all the domains assessed were assigned to Cluster 1, whereas the children in Cluster 3 were characterized by relatively minor problems. Cluster 2 comprised children with moderate difficulties in the different domains. Compared to the TD group, group 1, with 'Serious Difficulties', and group 2, with 'Moderate Difficulties', showed significant differences on all the variables evaluated. Group 3, 'Slight Difficulties', was only significantly differentiated from the group with TD on ASD and attention deficit hyperactivity disorder (ADHD) symptoms, pragmatic competence, and applied theory of mind. Therefore, it was outlined as the purest group and basically manifested core ASD symptoms. In addition, mothers of children in the 'Serious Difficulties' group showed higher stress levels and less use of emotional and instrumental support and acceptance strategies, as well as more mental health problems, than mothers of children in the 'Slight Difficulties' group. The results support the need to assess the presentation of other possible problems in ASD children without ID, and design interventions for parents who may be at risk of experiencing higher levels of stress and have fewer coping strategies.

Attention as neurocognitive endophenotype of ADHD across the life span: a family study

Endophenotypes mediate pathways between genetic variations and the psychiatric phenotype, or share genetic risk with the psychiatric phenotype. Identifying endophenotypes is an important step to unravel disease pathways underlying complex psychiatric phenotypes such as ADHD. Potential viable endophenotypes for ADHD across the lifespan are neurocognitive measures of basic attention functions, such as sustained attention, and executive attention functions (EF), such as inhibition. The present study evaluated the endophenotype criteria of familiality and state-independency for measures of basic attention and EF in affected- and unaffected parents of children with ADHD (N = 139), and typically developing children (N = 60). In addition, the added value of neurocognitive measures relative to questionnaire data in genetically informed designs was explored by comparing the intergenerational transmission of neurocognitive measures to those of ADHD symptom scores. Results revealed small-to-medium-sized familial effects of ADHD for reaction time measures of EF components and state-independency given familial effects. Parent-child correlations as estimates of intergenerational transmission of those neurocognitive measures were not higher than those of behavioral ADHD symptom ratings. Taken together, our results argue against neurocognitive measures as pivotal endophenotypes for ADHD across the lifespan. If studied as neurocognitive endophenotypes of ADHD in adults, reaction time measures of executive-rather than basic attention function-seem to be more sensitive.

From bedside to bench and back: Translating ASD models

Autism spectrum disorders (ASD) represent a heterogeneous group of disorders defined by deficits in social interaction/communication and restricted interests, behaviors, or activities. Models of ASD, developed based on clinical data and observations, are used in basic science, the "bench," to better understand the pathophysiology of ASD and provide therapeutic options for patients in the clinic, the "bedside." Translational medicine creates a bridge between the bench and bedside that allows for clinical and basic science discoveries to challenge one another to improve the opportunities to bring novel therapies to patients. From the clinical side, biomarker work is expanding our understanding of possible mechanisms of ASD through measures of behavior, genetics, imaging modalities, and serum markers. These biomarkers could help to subclassify patients with ASD in order to better target treatments to a more homogeneous groups of patients most likely to respond to a candidate therapy. In turn, basic science has been responding to developments in clinical evaluation by improving bench models to mechanistically and phenotypically recapitulate the ASD phenotypes observed in clinic. While genetic models are identifying novel therapeutics targets at the bench, the clinical efforts are making progress by defining better outcome measures that are most representative of meaningful patient responses. In this review, we discuss some of these challenges in translational research in ASD and strategies for the bench and bedside to bridge the gap to achieve better benefits to patients.