Children with autism spectrum disorder comorbid with attention-deficit/hyperactivity disorder examined by the Wisconsin card sorting test: Analysis by age-related differences

Category learning in autistic individuals: A meta-analysis

Learning new categories is a fundamental human skill. In the present article, we report the first comprehensive meta-analysis of category learning in autism. Including studies comparing groups of autistic and nonautistic individuals, we investigated whether autistic individuals differ in category learning from nonautistic individuals. In addition, we examined moderator variables accounting for variability between studies. A multilevel meta-analysis of k = 50 studies examining n = 1,220 autistic and n = 1,445 nonautistic individuals based on 112 effect sizes in terms of the standardized mean difference revealed lower-level category learning skills for autistic compared with nonautistic individuals, g = -0.55, 95% CI = [-0.73, -0.38], p < .0001. According to moderator analyses, the significant amount of heterogeneity, Q(111) = 617.88, p < .0001, was explained by only one of the moderator variables under investigation-namely, study language. For the remaining variables-namely, age, year of publication, risk of bias, type of control group, IQ of autistic group, percentage of male autistic participants, type of category, type of task, and type of dependent measure-there were no significant effects. Although hat values and Cook's distance statistics confirmed the robustness of findings, results of Egger's test and a funnel plot suggested the presence of publication bias reflecting an overrepresentation of disadvantageous findings for autistic groups. Objectives for future work include identifying additional moderator variables, examining downstream effects of suboptimal category learning skills, and developing interventions.

A meta-analysis of cognitive flexibility in autism spectrum disorder

Cognitive flexibility is a fundamental process that underlies adaptive behaviour in response to environmental change. Studies examining the profile of cognitive flexibility in autism spectrum disorder (ASD) have reported inconsistent findings. To address whether difficulties with cognitive flexibility are characteristic of autism, we conducted a random-effects meta-analysis and employed subgroup analyses and meta-regression to assess the impact of relevant moderator variables such as task, outcomes, and age. Fifty-nine studies were included and comprised of 2122 autistic individuals without intellectual disabilities and 2036 neurotypical controls, with an age range of 4 to 85 years. The results showed that autistic individuals have greater difficulties with cognitive flexibility, with an overall statistically significant small to moderate effect size. Subgroup analyses revealed a significant difference between task outcomes, with perseverative errors obtaining the largest effect size. In summary, the present meta-analysis highlights the existence of cognitive flexibility difficulties in autistic people, in the absence of learning disabilities, but also that this profile is characterised by substantial heterogeneity. Potential contributing factors are discussed.

Characterization of a mGluR5 Knockout Rat Model with Hallmarks of Fragile X Syndrome

The number of reported cases of neurodevelopmental disorders has increased significantly in the last few decades, but the etiology of these diseases remains poorly understood. There is evidence of a fundamental link between genetic abnormalities and symptoms of autism spectrum disorders (ASDs), and the most common monogenetic inheritable form of ASDs is Fragile X Syndrome (FXS). Previous studies indicate that FXS is linked to glutamate signaling regulation by the G-protein-coupled metabotropic glutamate receptor 5 (mGluR5), which has been shown to have a regulatory role in neuroinflammation. We characterized the effect of knocking out mGluR5 in an organism known to have complex cognitive functions—the rat. The heterozygous phenotype is the most clinically relevant; therefore, we performed analysis in heterozygous pups. We showed developmental abnormalities in heterozygous mGluR5 knockout rats, as well as a significant increase in chemokine (C-X-C motif) ligand 1 (CXCL) expression, a hallmark indicator of early onset inflammation. We quantified an increase in microglial density in the knockout pups and quantified morphological phenotypes representative of greater reactivity in the male vs. female and postnatal day 28 heterozygous pups compared to postnatal day 14 heterozygous pups. In response to injury, reactive microglia release matrix metalloproteases, contribute to extracellular matrix (ECM) breakdown, and are responsible for eradicating cellular and molecular debris. In our study, the changes in microglial density and reactivity correlated with abnormalities in the mRNA expression levels of ECM proteins and with the density of perineuronal nets. We saw atypical neuropsychiatric behavior in open field and elevated plus tests in heterozygous pups compared to wild-type litter and age-matched controls. These results demonstrate the pathological potential of the mGluR5 knockout in rats and further support the presence of neuroinflammatory roots in ASDs.

Cognitive and behavioral profiles in children with autism spectrum disorder with and without Attention-Deficit/hyperactivity disorder

BACKGROUND

Understanding the developmental trajectories of children with autism spectrum disorder (ASD) with and without comorbid ADHD is relevant to tailor care plans. This prospective study assessed, for the first time, cognitive, emotional, behavioral, and learning outcomes in adolescence of children with ASD-ADHD and in those with ASD+ADHD in childhood. Possible predictors of severity of ASD core symptoms in adolescence were also evaluated.

METHODS

Forty-five adolescents without intellectual disability, 26 diagnosed in childhood with ASD-ADHD and 19 with ASD+ADHD, were evaluated at baseline (mean age: 8.6 ± 1.3) and at 5-year follow-up (mean age: 12.9 ± 0.9). Parents and teachers completed questionnaires on executive functions, theory of mind (ToM), emotional/behavioral difficulties (EBD), and learning style at both time points..

RESULTS

Overall different developmental trajectories for the two groups were found. In general, deficits in metacognition processes, ToM skills, EBD, and learning abilities were more pronounced in the ASD+ group. Over time, the ASD+ADHD group, but not the ASD-ADHD, tended to improve in EBD and metacognition but their level of development continued to be lower compared with ASD+ADHD. EBD in childhood were significant predictors of autism core symptoms of adolescents.

CONCLUSIONS

Our findings highlight the importance of an early identification of comorbid ADHD symptoms in ASD to offer treatment strategies based on specific developmental trajectories.

Cognitive, social, and behavioral manifestations of the co-occurrence of autism spectrum disorder and attention-deficit/hyperactivity disorder: A systematic review

LAY ABSTRACT

This work aimed to review recent research on the characteristics of individuals who have both autism spectrum disorder and attention-deficit/hyperactivity disorder due to their high co-occurrence. Thirty-four studies were analyzed and main findings summarized in two content domains focusing on areas that could enhance our understanding of the cognitive and behavioral characteristics of individuals with autism spectrum disorder + attention-deficit/hyperactivity disorder (ASD+). Most of the results suggested that ASD+ is a co-occurring condition associated with more severe impairments in cognitive functioning, adaptive behavior, and increased likelihood to present more emotional/behavioral problems. These results will be helpful to provide improved care plans for individuals with both attention-deficit/hyperactivity disorder and autism spectrum disorder.

Automatic Intra-/Extra-Dimensional Attentional Set-Shifting Task in Adolescent Mice

Adolescence is a developmental period crucial for the maturation of higher-order cognitive functions. Indeed, adolescence deficits in executive functions are strong predictors of increased vulnerability to several mental disabilities later in life. Here, we tested adolescent mice in a fully-automated attentional set-shifting task equivalent to the humans' Wisconsin Card Sorting Test (WCST) and the Cambridge Neuropsychological Test Automated Battery Intra-/Extra-Dimensional set-shift task (ID/ED). Compared to an adult, adolescent mice required more time to complete the task (≈16 days), and a higher percentage failed to finish the entire task. Nevertheless, adolescent mice completing this demanding task showed an increased effort in solving the extradimensional shift stage (EDS) compared to previous stages. Moreover, we found that this paradigm can be used to detect early cognitive dysfunctions in adolescent genetically modified mice. Thus, this automatic paradigm provides a further tool to assess attentional control in adolescent mice, and the development of dysfunctional executive functions from adolescence to adulthood.

Examining the roles of cognitive flexibility, emotion recognition, and metacognitions in adult Attention Deficit and Hyperactivity Disorder with predominantly inattentive presentation

The evaluation of cognitive functions in Attention Deficit and Hyperactivity Disorder (ADHD) is fundamental to improve the efficacy of therapeutic interventions. However, the role of specific higher-order cognitive functions in adult ADHD, including cognitive flexibility, emotion recognition, and metacognitions, remains unclear. Therefore, in the current study, we aimed to examine these three distinct higher-order cognitive functions among adult ADHD individuals. Forty patients with ADHD with predominantly inattentive presentation and 42 healthy controls participated in the study. The Adult Attention Deficit and Hyperactivity Disorder Scale (AADHDS), the Wisconsin Card Sorting Test (WCST), the Reading the Mind in the Eyes Test (RMET), and the Metacognitions Questionnaire-30 (MCQ-30) were administered. Results indicated that patients with ADHD had worse metacognitions scores, in specific subdimensions, relative to healthy controls. However, cognitive flexibility and emotion recognition did not differ between the groups. Moreover, the cognitive confidence subdimension of the MCQ-30 was found to be sole significant predictor in the attention deficit subdimension of the AADHDS. Our findings suggest that lack of cognitive confidence may contribute to ADHD symptomatology despite regularly functioning cognitive flexibility and emotion recognition. Therefore, metacognitions could be a suitable target to alleviate the severity of ADHD symptoms.

Efficacy and Safety of Melatonin Treatment in Children with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder-A Review of the Literature

Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are neurodevelopmental disorders with disturbed melatonin secretion profile and sleep problems. The growing incidence of ASD and ADHD inspires scientists to research the underlying causes of these conditions. The authors focused on two fundamental aspects, the first one being the presentation of the role of melatonin in ASD and ADHD and the second of the influence of melatonin treatment on sleep disorders. The authors present the use of melatonin both in the context of causal and symptomatic treatment and discuss melatonin supplementation: Dosage patterns, effectiveness, and safety. Sleep disorders may have a different clinical picture, so the assessment of exogenous melatonin efficacy should also refer to a specific group of symptoms. The review draws attention to the wide range of doses of melatonin used in supplementation and the need to introduce unified standards especially in the group of pediatric patients.