No abstract

Summary Autism spectrum disorder (ASD), a neurodevelopmental disorder affecting nearly 1 in 88 children, is thought to result from aberrant brain connectivity. Remarkably, there have been no systematic attempts to characterize whole-brain connectivity in children with ASD. Here, we use neuroimaging to show there are more instances of greater functional connectivity in the brains of children with ASD compared with typically developing children. Hyper-connectivity in ASD was observed at the whole-brain and subsystems level, across long- and short-range connections, and was associated with higher levels of fluctuations in regional brain signals. Brain hyper-connectivity predicted symptom severity in ASD such that children with greater functional connectivity exhibited more severe social deficits. We replicated these findings in two additional independent cohorts, demonstrating again that at earlier ages, the brain in ASD is largely functionally hyper-connected in ways that contribute to social dysfunction. Our findings provide novel insights into brain mechanisms underlying childhood autism.

No abstract

In this paper, we review the most recent and often conflicting findings on conventional measures of executive control in autism spectrum disorders. We discuss the obstacles to accurate measurement of executive control, such as: its prolonged developmental trajectory; lack of consensus on its definition and if it is a unitary construct; the inherent complexity of executive control; and the difficulty measuring executive control functions in laboratory or clinical settings. We review the potential of an ecological validity framework to address some of these problems, and describe new tests claiming verisimilitude, or close resemblance to "real life" demands. We also review the concept of veridicality, which allows for the measurement of the ecological validity of any task, and discuss the few studies addressing ecological validity in individuals with autism. Our review suggests that a multi-source approach emphasizing veridicality may provide the most comprehensive assessment of executive control in autism. KeywordsExecutive Function; Autism; Ecological Validity; Asperger's; Cognitive Control; Neuropsychology Executive control is a widely studied construct in the field of autism spectrum disorders, henceforth referred to in this paper as autism. Though the research findings are inconsistent (see below), most clinicians, teachers, and family members agree that individuals with autism have difficulties with various aspects of executive control in their daily lives. This review will explore this discrepancy by addressing the following three questions:1. What do we know about conventional executive control tasks and autism? 2. Why is the executive control profile in autism so confusing?3. Where do we go from here?Our goal is to highlight novel areas of research in this field that could: advance the study of executive control in autism; improve its ability to capture the daily executive control obstacles that impair individuals with autism; and provide new targets for intervention.

Executive function profiles were examined within and between several clinical disorders via the multi-domain Behavior Rating Inventory of Executive Function (BRIEF; Gioia, Isquith, Guy, & Kenworthy, 2000). Parent ratings of children with Inattentive and Combined types of Attention-Deficit/Hyperactivity Disorder (ADHD-I, ADHD-C), Autistic Spectrum Disorders (ASD), moderate and severe Traumatic Brain Injury (TBI), and Reading Disabilities (RD) were compared with controls. Profile analysis revealed significant (p<.01) and substantial (eta2>.10) differences in global elevations and in profile of scale elevations between diagnostic groups. ASD, ADHD-I and ADHD-C groups exhibited greater elevations across the BRIEF scales than did RD and Severe TBI groups, who were in turn more elevated than Moderate TBI and Control groups. The ADHD-C group was unique in its frequency and severity of inhibitory deficits, while the ASD group was distinguishable by its deficits in flexibility. Within diagnostic groups, relative risk for executive dysfunction was calculated with variability present in the frequency of clinically elevated scales. While the BRIEF captures executive profiles characteristic of specific disorders in the clinical setting, it is not diagnostic in its own right and is best used within the context of a broad based evaluation.

Verbal fluency tasks have been widely used to evaluate language and executive control processes in the human brain. FMRI studies of verbal fluency, however, have used either silent word generation (which provides no behavioral measure) or cued generation of single words in order to contend with speech-related motion artifacts. In this study, we use a recently developed paradigm design to investigate the neural correlates of verbal fluency during overt, free recall, word generation so that performance and brain activity could be evaluated under conditions that more closely mirror standard behavioral test demands. We investigated verbal fluency to both letter and category cues in order to evaluate differential involvement of specific frontal and temporal lobe sites as a function of retrieval cue type, as suggested by previous neuropsychological and neuroimaging investigations. In addition, we incorporated both a task switching manipulation and an automatic speech condition in order to modulate the demand placed on executive functions. We found greater activation in the left hemisphere during category and letter fluency tasks, and greater right hemisphere activation during automatic speech. We also found that letter and category fluency tasks were associated with differential involvement of specific regions of the frontal and temporal lobes. These findings provide converging evidence that letter and category fluency performance is dependent on partially distinct neural circuitry. They also provide strong evidence that verbal fluency can be successfully evaluated in the MR environment using overt, self-paced, responses.

There is active debate regarding the nature of executive dysfunction in autism. Additionally, investigations have yet to show a relationship between deficits in executive function and the everyday behavioral difficulties that may originate from them. The present study examined the relationship between executive abilities and adaptive behavior in 35 children with Autism Spectrum Disorders, using two parent reports of everyday functioning, the Vineland Adaptive Behavior Scales (VABS) and the Behavior Rating Inventory of Executive Function (BRIEF). Results found several relationships: The Initiate and Working Memory domains were negatively correlated with most domains of adaptive behavior. Also, the Communication and Socialization domains of the VABS were negatively correlated with several areas of executive functioning, suggesting that impairments in executive abilities are strongly associated with the deficits in communication, play and social relationships found in children with autism.

Background Unstuck and On Target (UOT) is an executive function (EF) intervention for children with autism spectrum disorders (ASD) targeting insistence on sameness, flexibility, goal-setting and planning through a cognitive-behavioral program of self-regulatory scripts, guided/faded practice, and visual/verbal cueing. UOT is contextually-based because it is implemented in school and at home, the contexts in which a child uses EF skills. Methods To evaluate the effectiveness of UOT as compared to a social skills intervention (SS), 3rd-5th graders with ASD (mean IQ=108; UOT n=47; SS n=20) received interventions delivered by school staff in small group sessions. Students were matched for sex, age, race, intelligence, ASD symptomotolgy, medication status, and parent education. Interventions were matched for “dose” of intervention and training. Measures of pre-post change included classroom observations, parent/teacher report and direct child measures of problem-solving, EF, and social skills. Schools were randomized and evaluators, but not parents or teachers, were blind to intervention type. Results Interventions were administered with high fidelity. Children in both groups improved with intervention, but mean change scores from pre- to post-intervention indicated significantly greater improvements for UOT than SS groups in: problem-solving, flexibility, and planning/organizing. Also, classroom observations revealed that participants in UOT made greater improvements than SS participants in their ability to follow rules, make transitions, and be flexible. Children in both groups made equivalent improvements in social skills. Conclusions These data support the effectiveness of the first contextually-based EF intervention for children with ASD. UOT improved classroom behavior, flexibility and problem-solving in children with ASD. Individuals with variable background/training in ASD successfully implemented UOT in mainstream educational settings.