Autism spectrum disorders: a meta-analysis of executive function

Frontal lobe dysfunction underlies the differential word retrieval impairment in adolescents with high-functioning autism

There is substantial evidence of word retrieval impairment as indicated by poor performance on the category fluency test in autism spectrum disorder (ASD). However, little is known about the neural mechanisms underlying this impairment. Functional neuroimaging studies have shown that the lateral frontal cortex plays a key role in flexible word retrieval. Thus, we examined whether individuals with ASD exhibited altered frontal processing during the category fluency test using functional near-infrared spectroscopy (fNIRS). Twenty-two adolescents with high-functioning ASD (20 males) and 22 typically developing (TD) adolescents (16 males) aged 11-18 years were recruited. All underwent a category fluency paradigm, which required production of animal or means of transportation words for 1 min each although their frontal hemodynamic changes were recorded with fNIRS. We found that adolescents with ASD produced fewer animal but not transportation words (group-by-category interaction: P = 0.003), suggesting differential word retrieval impairment. In addition, unlike TD adolescents who exhibited activation primarily in lateral frontal regions during word production, adolescents with ASD had comparable activation across lateral and medial frontal regions. More importantly, this lack of lateral-medial distinction of activation, which was associated with poor word retrieval, differed significantly between groups only in the animal category (group-by-category interaction: P = 0.018). Thus, our findings implicate frontal lobe dysfunction in the impairment of differential word retrieval in adolescents with ASD. The relatively greater involvement of the medial frontopolar cortex might reflect the use of nonspecialized brain regions to compensate for the category-dependent difficulties with word retrieval in ASD. Autism Res 2019, 12: 600-613. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Using an optical imaging tool, we found that adolescents with autism had difficulties with producing semantically related words and exhibited frontal lobe dysfunction. Nonetheless, poor word production and altered brain processing was only seen when these adolescents were asked to produce words from a category of living things but not nonliving things (i.e., animals but not means of transportation). Category-dependent word retrieval problems and frontal lobe dysfunction might be two features of this disorder.

Patterns of Nonsocial and Social Cognitive Functioning in Adults With Autism Spectrum Disorder: A Systematic Review and Meta-analysis

IMPORTANCE

Many studies have investigated impairments in cognitive domains in adults with autism spectrum disorder (ASD). Yet, to date, a comprehensive overview on the patterns of cognitive functioning is lacking.

OBJECTIVE

To provide an overview of nonsocial and social cognitive functioning in various domains in adults with ASD, allowing for comparison of the severity of deficits between different domains.

DATA SOURCES

A literature search performed in an academic medical setting was conducted using PubMed, PsycINFO, Embase, and Medline databases with the combination of the following free-text and Medical Subject Headings where applicable: [cogniti* OR neurocogniti* OR neuropsycholog* OR executive function* OR IQ OR intelligence quotient OR social cognition OR emotion perception OR affect perception OR emotion recognition OR attribution OR ToM OR mentalising OR mentalizing OR prosody OR social knowledge OR mind reading OR social cue OR social judgment] AND [autis* OR ASD OR Asperger OR Asperger's OR PDD OR pervasive developmental disorder]. The search was further limited to studies published between 1980 (first inclusion of autism diagnosis in the DSM-III) and July 2018.

STUDY SELECTION

Studies included were published as a primary peer-reviewed research article in English, included individuals with ASD 16 years or older, and assessed at least 1 domain of neurocognitive functioning or social cognition using standard measures.

DATA EXTRACTION AND SYNTHESIS

Of 9892 articles identified and screened, 75 met the inclusion criteria for the systematic review and meta-analysis.

MAIN OUTCOMES AND MEASURES

Hedges g effect sizes were computed, and random-effects models were used for all analyses. Moderators of between-study variability in effect sizes were assessed using meta-regressions.

RESULTS

The systematic review and meta-analysis included 75 studies, with a combined sample of 3361 individuals with ASD (mean [SD] age, 32.0 [9.3] years; 75.9% male) and 5344 neurotypical adults (mean [SD] age, 32.3 [9.1] years; 70.1% male). Adults with ASD showed large impairments in theory of mind (g = -1.09; 95% CI, -1.25 to -0.92; number of studies = 39) and emotion perception and processing (g = -0.80; 95% CI, -1.04 to -0.55; n = 18), followed by medium impairments in processing speed (g = -0.61; 95% CI, -0.83 to -0.38; n = 21) and verbal learning and memory (g = -0.55; 95% CI, -0.86 to -0.25; n = 12). The least altered cognitive domains were attention and vigilance (g = -0.30; 95% CI, -0.81 to 0.21; n = 5) and working memory (g = -0.23; 95% CI, -0.47 to 0.01; n = 19). Meta-regressions confirmed robustness of the results.

CONCLUSIONS AND RELEVANCE

Results of this systematic review and meta-analysis suggest that adults with ASD show impairments in social cognitive domains and in specific nonsocial cognitive domains. These findings contribute to the understanding of the patterns of cognitive functioning in adults with ASD and may assist in the identification of targets for cognitive interventions.

A Pilot Study of the Efficacy of a Cognitive Training Based on Board Games in Children with Attention-Deficit/Hyperactivity Disorder: A Randomized Controlled Trial

Objective: The main aim of this study was to prove the efficacy of an intervention based on board games on executive functions (EFs) and clinical symptoms in children with attention-deficit/hyperactivity disorder (ADHD). Materials and Methods: A nonblinded randomized controlled trial was conducted with a sample of children with a diagnosis of ADHD (diagnosed by psychiatrists and clinical psychologists in a mental health center). Children were randomly allocated by matching age and sex, into two groups: experimental EF training group (n = 13; mean [M]_age = 9.46, standard deviation [SD] = 1.20; boys = 53.8%) or a wait-list control group (n = 14; M_age = 9.50, SD = 1.09; boys = 71.4%). Measures assessed individually at pretest, posttest, and follow-up intervention included EFs and clinical symptoms. Results: Analysis of covariance repeated measures analysis showed that linguistic short-term memory, F(1,28) = 7.45, p = 0.02, and conduct problems, F(1,28) = 12.51, p = 0.00, significantly improved with larger effects in the board games training group after intervention when compared to the wait-list group. Although nonsignificant effects were reported at the follow-up, large effect sizes were actually found. Conclusion: Although future studies are needed, the results of this study highlight the importance of board games and its efficacy as a possible therapeutic and/or preventive intervention on ADHD.

Age-moderating effect in prepotent response inhibition in boys with Asperger syndrome: a 2.5 years longitudinal study

Following our previous cross-sectional analysis, indicating age-related improvements of response inhibition in a random-motor-generation task (MPT) in adolescents with Asperger syndrome (AS), the present study reports data from a 2.5-year follow-up examination in the original sample. We found more marked improvements within the follow-up interval in younger AS children, while older AS boys as well as typically developing (TD) boys remained at a relatively constant level throughout. The current longitudinal study further substantiates the notion that AS children (on average) catch up with TD children when they grow older as regards the basic inhibition of developing routine response patterns.

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.

Impairments in cognitive empathy and alexithymia occur independently of executive functioning in college students with autism

Reduced empathy and alexithymic traits are common across the autism spectrum, but it is unknown whether this is also true for intellectually advanced adults with autism spectrum disorder. The aim of this study was to examine whether college students with autism spectrum disorder experience difficulties with empathy and alexithymia, and whether this is associated with their cognitive levels of executive functioning. In total, 53 college students with autism spectrum disorder were compared to a gender-matched group of 29 neurotypical students on cognitive and affective dimensions of empathy and alexithymia. In addition, cognitive performance on executive functioning was measured with computerized and paper-and-pencil tasks. The autism spectrum disorder group scored significantly lower on cognitive empathy and higher on cognitive alexithymia (both d = 0.65). The difference on cognitive empathy also remained significant after controlling for levels of cognitive alexithymia. There were no group differences on affective empathy and alexithymia. No significant relations between executive functioning and cognitive alexithymia or cognitive empathy were detected. Together, these findings suggest that intellectually advanced individuals with autism spectrum disorder experience serious impairments in the cognitive processing of social–emotional information. However, these impairments cannot be attributed to individual levels of cognitive executive functioning.

Brain Connectivity and Neuroimaging of Social Networks in Autism

Impairments in social communication (SC) predominate among the core diagnostic features of autism spectrum disorders (ASDs). Neuroimaging has revealed numerous findings of atypical activity and connectivity of 'social brain' networks, yet no consensus view on crucial developmental causes of SC deficits has emerged. Aside from methodological challenges, the deeper problem concerns the clinical label of ASD. While genetic studies have not comprehensively explained the causes of nonsyndromic ASDs, they highlight that the clinical label encompasses many etiologically different disorders. The question of how potential causes and etiologies converge onto a comparatively narrow set of SC deficits remains. Only neuroimaging designs searching for subtypes within ASD cohorts (rather than conventional group level designs) can provide translationally informative answers.

Aberrant functional connectivity of inhibitory control networks in children with autism spectrum disorder

Development of inhibitory control is a core component of executive function processes and a key aspect of healthy development. Children with autism spectrum disorder (ASD) show impairments in performance on inhibitory control tasks. Nevertheless, the research on the neural correlates of these impairments is inconclusive. Here, we explore the integrity of inhibitory control networks in children with ASD and typically developing (TD) children using resting state functional Magnetic Resonance Imagaing (MRI). In a large multisite sample, we find evidence for significantly greater functional connectivity (FC) of the right inferior frontal junction (rIFJ) with the posterior cingulate gyrus, and left and right frontal poles in children with ASD compared with TD children. Additionally, TD children show greater FC of rIFJ with the superior parietal lobule (SPL) compared with children with ASD. Furthermore, although higher rIFJ-SPL and rIFJ-IPL FC was related to better inhibitory control behaviors in both ASD and TD children, rIFJ-dACC FC was only associated with inhibitory control behaviors in TD children. These results provide preliminary evidence of differences in intrinsic functional networks supporting inhibitory control in children with ASD, and provide a basis for further exploration of the development of inhibitory control in children with the disorder. Autism Research 2018, 11: 1468-1478. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Inhibitory control is an important process in healthy cognitive development. Behavioral studies suggest that inhibitory control is impaired in autism spectrum disorder (ASD). However, research examining the neural correlates underlying inhibitory control differences in children with ASD is inconclusive. This study reveals differences in functional connectivity of brain networks important for inhibitory control in children with ASD compared with typically developing children. Furthermore, it relates brain network differences to parent-reported inhibitory control behaviors in children with ASD. These findings provide support for the hypothesis that differences in brain connectivity may underlie observable behavioral deficits in inhibitory control in children with the disorder.

Do you know what I'm thinking? Temporal and spatial brain activity during a theory-of-mind task in children with autism

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First MEG study of neural underpinnings of theory of mind differences in autism.

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Children with autism show decreased LTPJ activity from 300 to 375 and 425 to 500 ms.

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Children with autism also show increased RIFG activity from 325 to 375 ms.

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Co-incident lower LTPJ and higher RIFG activity implies compensatory use of RIFG.

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Executive functions may augment impaired theory of mind in autism.

The social impairments observed in children with autism spectrum disorder are thought to arise in part from deficits in theory of mind, the ability to understand other people’s thoughts and feelings. To determine the temporal-spatial dynamics of brain activity underlying these atypical theory-of-mind processes, we used magnetoencephalography to characterize the sequence of functional brain patterns (i.e. when and where) related to theory-of-mind reasoning in 19 high-functioning children with autism compared to 22 age- and sex-matched typically-developing children aged 8–12 during a false-belief (theory-of-mind) task. While task performance did not differ between the two groups, children with autism showed reduced activation in the left temporoparietal junction between 300–375 and 425–500 ms, as well as increased activation in the right inferior frontal gyrus from 325 to 375 ms compared to controls. The overlap in decreased temporoparietal junction activity and increased right inferior frontal gyrus activation from 325 to 375 ms suggests that in children with autism, the right inferior frontal gyrus may compensate for deficits in the temporoparietal junction, a neural theory-of-mind network hub. As the right inferior frontal gyrus is involved in inhibitory control, this finding suggests that children with autism rely on executive functions to bolster their false-belief understanding.

Autism, Early Psychosis, and Social Anxiety Disorder: a transdiagnostic examination of executive function cognitive circuitry and contribution to disability

The disability burden in clinical cohorts with social impairment is significant, leading to poor functional outcomes. Some of this impairment has been linked to executive dysfunction. In this study, a transdiagnostic approach was taken to identify executive function (EF) processes in young adults that may underpin social impairment and to evaluate their contribution to disability. Comparisons were made between three prominent disorders that are characterized by social impairments, Autism Spectrum Disorder (ASD), Early Psychosis (EP) and Social Anxiety Disorder (SAD), as well as a neurotypically developing group (TYP). We examined whether overall disability could be predicted by neuropsychological and self-report assessments of EF. Our study showed that ASD participants demonstrated impaired performance on most domains of EF compared to the TYP group (mental flexibility, sustained attention and fluency) while the EP group showed impairment on sustained attention and attentional shifting. The SAD participants showed EF impairment on self-report ratings, even though their objective performance was intact. Self-reports of EF explained a significant percentage (17%) of disability in addition to the variance explained by other predictors, and this was particularly important for ASD. This is the first study to compare EF measures across clinical groups of social impairment and suggests unique cognitive-circuitry that underpins disability within groups. Impairments in EF were broad in ASD and predicted disability, EP impairments were specific to attentional processes and SAD impairments likely relate to negative self-monitoring. Self-report, as opposed to performance-based EF, provided best capacity to predict disability. These findings contribute to transdiagnostic circuitry models and intervention strategies.

Neural Mechanisms of Qigong Sensory Training Massage for Children With Autism Spectrum Disorder: A Feasibility Study

OBJECTIVES

Despite the enormous prevalence of autism spectrum disorder (ASD), its global impact has yet to be realized. Millions of families worldwide need effective treatments to help them get through everyday challenges like eating, sleeping, digestion, and social interaction. Qigong Sensory Training (QST) is a nonverbal, parent-delivered intervention recently shown to be effective at reducing these everyday challenges in children with ASD. This study tested the feasibility of a protocol for investigating QST's neural mechanism.

METHODS

During a single visit, 20 children, 4- to 7-year-old, with ASD viewed images of emotional faces before and after receiving QST or watching a video (controls). Heart rate variability was recorded throughout the visit, and power in the high frequency band (0.15-0.4 Hz) was calculated to estimate parasympathetic tone in 5-s nonoverlapping windows. Cerebral oximetry of prefrontal cortex was recorded during rest and while viewing emotional faces.

RESULTS

95% completion rate and 7.6% missing data met a priori standards confirming protocol feasibility for future studies. Preliminary data suggest: (1) during the intervention, parasympathetic tone increased more in children receiving massage (M = 2.9, SD = 0.3) versus controls (M = 2.5, SD = 0.5); (2) while viewing emotional faces post-intervention, parasympathetic tone was more affected (reduced) in the massage group (p = 0.036); and (3) prefrontal cortex response to emotional faces was greater after massage compared to controls. These results did not reach statistical significance in this small study powered to test feasibility.

DISCUSSION/CONCLUSION

This study demonstrates solid protocol feasibility. If replicated in a larger sample, these findings would provide important clues to the neural mechanism of action underlying QST's efficacy for improving sensory, social, and communication difficulties in children with autism.

The Gestalt of functioning in autism spectrum disorder: Results of the international conference to develop final consensus International Classification of Functioning, Disability and Health core sets

Autism spectrum disorder is associated with diverse social, educational, and occupational challenges. To date, no standardized, internationally accepted tools exist to assess autism spectrum disorder–related functioning. World Health Organization’s International Classification of Functioning, Disability and Health can serve as foundation for developing such tools. This study aimed to identify a comprehensive, a common brief, and three age-appropriate brief autism spectrum disorder Core Sets. Four international preparatory studies yielded in total 164 second-level International Classification of Functioning, Disability and Health candidate categories. Based on this evidence, 20 international autism spectrum disorder experts applied an established iterative decision-making consensus process to select from the candidate categories the most relevant ones to constitute the autism spectrum disorder Core Sets. The consensus process generated 111 second-level International Classification of Functioning, Disability and Health categories in the Comprehensive Core Set for autism spectrum disorder—one body structure, 20 body functions, 59 activities and participation categories, and 31 environmental factors. The Common Brief Core Set comprised 60 categories, while the age-appropriate core sets included 73 categories in the preschool version (0- to 5-year-old children), 81 in the school-age version (6- to 16-year-old children and adolescents), and 79 in the older adolescent and adult version (⩾17-year-old individuals). The autism spectrum disorder Core Sets mark a milestone toward the standardized assessment of autism spectrum disorder–related functioning in educational, administrative, clinical, and research settings.

Neuropsychological assessment in autism spectrum disorder and related conditions

Neuropsychological assessment provides a profound analysis of cognitive functioning in people with autism spectrum disorder (ASD). Individuals on the autistic spectrum often show a high level of anxiety and are frequently affected by comorbidities that influence their quality of life. Yet, they also have cognitive strengths that should be identified in order to develop effective support strategies. This article presents an overview of five cognitive areas that are essential for neuropsychological evaluation (ie, intelligence, attention, executive function, social cognition, and praxis) and explores the underlying causes of behavioral problems in persons with ASD. Furthermore, it stresses the importance of meticulous neuropsychological testing with regard to cognitive remediation, a method that can help to enhance single cognitive processes in a targeted manner. Objective test results suggest it might be possible to promote an improved sense of coherence. In line with the salutogenic model, this may be fundamental for human health and well-being.

Early executive dysfunction in ASD: Simple versus complex skills

Despite the strong evidence of executive function (EF) impairment in Autism Spectrum Disorder (ASD), findings in the preschool period have been inconsistent. Whereas some research has supported an early deficit, many studies have not found early differences in EF. The present study assessed simple and complex components of three EF abilities: working memory, inhibition, and shifting, using a novel battery, the Preschool EF Battery (PEFB; Garon, Smith & Bryson, Child Neuropsychology, 20, 713-736, 2014). Previous research has indicated that the PEFB is sensitive to age differences in typically developing (TD) children aged 18-60 months. Current participants were 34 preschoolers (M = 54.79 months) diagnosed with ASD and 255 TD preschoolers (M = 42.98 months). Results indicated significant differences between the two groups in the three EF abilities, but specific findings were moderated by mental and chronological age. The findings highlight the importance of testing simpler EF skills in very young children with ASD. Autism Res 2018, 11: 318-330. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

LAY SUMMARY

Given that executive functions (EF) have been found to predict various outcomes such as academic ability and occupational success, sensitive early assessment is important. The current study suggests the presence of early EF deficits in preschool children with autism spectrum disorder. The study highlights the importance of considering how EF develops during early life in typically developing children in order to design sensitive EF measures.