Brief Report: A Preliminary Study of the Relationship between Repetitive Behaviors and Concurrent Executive Function Demands in Children with Autism Spectrum Disorder.

The present study evaluated the hypothesis that the strength of the relationship between executive function (EF) and repetitive behaviors and restricted interests (RBRI) symptomatology is moderated by the degree to which concurrent demands are placed on multiple aspects of EF. An eye movement task was used to evaluate inhibition and task switching ability (both together and in isolation) in a sample of 22 children with autism spectrum disorder (ASD). The Repetitive Behavior Scale-Revised (RBS-R) was used to assess the severity of RBRI symptoms. Results provide preliminary support for the aforementioned hypothesis. RBS-R scores were significantly correlated with task performance when simultaneous demands were placed on switching and inhibition; however, no such relationship was found for inhibition-only or switching-only task conditions.

Contributions of filtering and attentional allocation to working memory performance in individuals with autism spectrum disorder.

Past findings on working memory (WM) ability in individuals with autism spectrum disorder (ASD) are mixed. The present objective was to assess not only the integrity of WM capacity, but also the potential contribution of filtering ability and attentional selection to WM performance, in individuals with ASD. A sample of 24 participants with ASD (Mage = 19.6 years) and 24 typically developing participants without ASD (Mage = 20.3 years) participated. Participants completed a computerized paradigm designed to systematically assess WM capacity, visual filtering ability, and attentional selection. In brief, participants were shown visual arrays consisting of 2-8 colored stimuli (circles and/or squares). After a short delay, memory for one of the stimuli was probed. Importantly, participants were informed beforehand that one of the shape types (e.g., circles) was more likely to be probed compared to the other shape type (e.g., squares) - thus making it strategically advantageous to focus on the high frequency shapes and to filter/ignore the low frequency shapes. Eye tracking data were simultaneously collected. The ASD group demonstrated intact WM capacity and filtering ability, but disrupted ability to efficiently allocate capacity under the demands of high WM load. Analysis of eye tracking data suggests the groups may have differed in their strategic approach to encoding stimuli which may have, in turn, contributed to the aforementioned impairment. Findings support the assertion that disruptions in secondary processes such as strategy use and attentional selection may have played a role in previous reports of WM impairment in ASD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Morphometric analysis of gray matter integrity in individuals with early-treated phenylketonuria.

The most widely-reported neurologic finding in individuals with early-treated phenylketonuria (PKU) is abnormality in the white matter of the brain. In contrast, much less is known regarding the impact of PKU on cortical gray matter (GM) structures. Presently, we applied advanced morphometric methods to the analysis of high-resolution structural MRI images from a sample of 19 individuals with early-treated PKU and an age- and gender-matched comparison group of 22 healthy individuals without PKU. Data analysis revealed decreased GM volume in parietal cortex for the PKU group compared with the non-PKU group. A similar trend was observed for occipital GM volume. There was no evidence of group-related differences in frontal or temporal GM volume. Within the PKU group, we also found a significant relationship between blood phenylalanine levels and GM volume for select posterior cortical sub-regions. Taken together with previous research on white matter and gray matter abnormalities in PKU, the present findings point to the posterior cortices as the primary site of neurostructural changes related to early-treated PKU.

Making Inferences: Comprehension of Physical Causality, Intentionality, and Emotions in Discourse by High-Functioning Older Children, Adolescents, and Adults with Autism.

Studies investigating inferential reasoning in autism spectrum disorder (ASD) have focused on the ability to make socially-related inferences or inferences more generally. Important variables for intervention planning such as whether inferences depend on physical experiences or the nature of social information have received less consideration. A measure of bridging inferences of physical causation, mental states, and emotional states was administered to older children, adolescents, and adults with and without ASD. The ASD group had more difficulty making inferences, particularly related to emotional understanding. Results suggest that individuals with ASD may not have the stored experiential knowledge that specific inferences depend upon or have difficulties accessing relevant experiences due to linguistic limitations. Further research is needed to tease these elements apart.

A Comparison of Measures for Assessing the Level and Nature of Intelligence in Verbal Children and Adults with Autism Spectrum Disorder.

Previous work has suggested that the Raven's Progressive Matrices (RPM) are better suited for capturing the nature of intelligence for individuals with autism spectrum disorder (ASD) than the Wechsler scales. The RPM measures 'fluid intelligence', an area for which it has been argued that persons with ASD have a relative strength. Given that measures of intelligence are used for establishing clinical diagnoses, for making educational decisions, and for group-matching in research studies, continued examination of this contention is warranted. In the current study, verbal children with ASD performed moderately better on the RPM than on the Wechsler scales; children without ASD received higher percentile scores on the Wechsler than on the RPM. Adults with and without ASD received higher percentile scores on the Wechsler than the RPM. Results suggest that the RPM and Wechsler scales measure different aspects of cognitive abilities in verbal individuals with ASD. For the verbal children and adults with ASD in the current study, the RPM and Wechsler scales have unique contributions that must be considered in context when establishing a baseline of cognitive function. The results of this investigation highlight the importance of thoughtfully selecting appropriate measures of intelligence consistent with clinical, educational, and research purposes, especially for verbal children and adults with ASD.

Effect of propranolol on facial scanning in autism spectrum disorder: a preliminary investigation.

BACKGROUND: Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social communication impairments and restricted, repetitive behaviors. Whereas current pharmacological interventions for ASD focus primarily on psychiatric symptoms, including agitation and obsessive behaviors, few agents target core symptomatology. It has been previously hypothesized that abnormalities in facial scanning, such as reduced eye contact or increased mouth fixation, contribute to social communication deficits in ASD. In addition, previous reports have suggested elevated stress and anxiety in ASD, symptoms that are believed to impact facial scanning patterns. OBJECTIVES: The present pilot study sought to explore the effects of pharmacological intervention via propranolol, a nonselective ß-adrenergic antagonist and known anxiolytic, on facial scanning in ASD. Specifically, we wished to determine whether there is an increase in eye contact and a decrease in mouth fixation with administration of propranolol. METHOD: A sample of 14 participants with ASD and 14 matched controls participated in two study sessions in which propranolol and placebo were administered in a counterbalanced, double-blinded manner. At each session, ocular fixation data were collected during presentation of video stimuli of 16 human faces. Fixation time on the eye, nose, and mouth regions of the face stimuli was analyzed. RESULTS: The baseline fixation patterns for the ASD and control groups did not significantly differ; however, administration of propranolol was associated with a significant reduction in mouth fixation for the ASD group. Additionally, mouth fixation was positively related to nonverbal communication impairment in the ASD group. CONCLUSIONS: Although eye fixation in ASD appears typical in the present study, the effect of propranolol in reducing mouth fixation suggests an important focus for further research. Future studies are needed to better characterize the relationship between stress and anxiety and facial scanning in ASD, as well as the effects of pharmacological intervention.

A volumetric study of basal ganglia structures in individuals with early-treated phenylketonuria.

Whereas the impact of early-treated phenylketonuria (ETPKU) on cortical white matter is well documented, relatively little is known regarding the potential impact of this metabolic disorder on deep gray matter structures such as the basal ganglia. The current study used high-resolution (1mm(3)) magnetic resonance imaging to investigate bilateral basal ganglia structures (i.e., putamen, caudate nucleus, and nucleus accumbens) in a sample of 13 individuals with ETPKU and a demographically-matched sample of 13 neurologically intact individuals without PKU. Consistent with previous research, we found smaller whole brain volumes in the ETPKU group compared with the non-PKU group. Individuals with ETPKU also had significantly larger putamen volumes than non-PKU individuals. In addition, the degree of putamen enlargement was correlated with blood phenylalanine levels and full scale IQ in the ETPKU group. These findings are consistent with the hypothesis that ETPKU-related increases in phenylalanine lead to decreased central dopamine levels thus impacting dopamine-dependent brain regions such as the putamen that play an important role in cognition.

Noradrenergic moderation of working memory impairments in adults with autism spectrum disorder.

In addition to having difficulties with social communications, individuals with an autism spectrum disorder (ASD) often also experience impairment in higher-order, executive skills. The present study examined the effects of pharmacological modulation of the norepinephrine system on the severity of such impairments. A sample of 14 high-functioning adults with ASD and a demographically-matched comparison group of 13 typically developing individuals participated. An AX continuous performance test (AX-CPT) was used to evaluate working memory and inhibitory control. AX-CPT performance was assessed following administration of a single dose of propranolol (a beta adrenergic antagonist) and following placebo (sugar pill) administration. Individuals with ASD performed more poorly than non-ASD individuals in the working memory condition (BX trials). Importantly, administration of propranolol attenuated this impairment, with the ASD group performing significantly better in the propranolol condition than the placebo condition. Working memory performance of the non-ASD group was unaffected by propranolol/placebo administration. No group or medication effects were observed for the inhibition condition (AY trials). The present findings suggest that norepinephrine may play a role in some, but not necessarily all, cognitive impairments associated with ASD. Additional research is needed to fully understand whether this role is primarily causal or compensatory in nature.

Evidence for selective inhibitory impairment in individuals with autism spectrum disorder.

OBJECTIVE: The social and communicative challenges faced by individuals with autism spectrum disorder (ASD) are often compounded by additional difficulties with executive function. It remains unclear, however, to what the extent individuals with ASD experienced impairment in inhibitory control. The objective of the present study was to assess the three main subtypes of executive inhibitory control within a single ASD sample thus providing new insight into the unique ASD-related pattern of sparing and impairment observed across different aspects of inhibitory control. METHOD: A sample of 28 children with ASD (mean age = 13.1 years) and a comparison group of 49 neurologically uncompromised children (mean age = 13.3 years) participated. A prepotent response inhibition task, a flanker visual filtering task, and a proactive interference memory task were used to evaluate prepotent response inhibition, resistance to distracter interference, and resistance to proactive interference, respectively. RESULTS: After accounting for individual differences in noninhibition abilities (e.g., processing speed) and overall level of functioning, there was no evidence of group-related differences in inhibitory performance on the prepotent response inhibition test or proactive interference test. ASD-related impairments in inhibitory control were evident, however, on the flanker visual filtering task. CONCLUSIONS: Taken together, the present findings indicate that ASD is associated with impairments in some, but not all, aspects of inhibitory control. Individuals with ASD appear to have difficulty ignoring distracting visual information, but prepotent response inhibition and resistance to proactive interference are relatively intact. The current findings also provide support for a multitype model of inhibitory control.

Effect of propranolol on word fluency in autism.

OBJECTIVE AND BACKGROUND: Autism is characterized by repetitive behaviors and impaired socialization and communication. Preliminary evidence showed possible language benefits in autism from the ß-adrenergic antagonist propranolol. Earlier studies in other populations suggested propranolol might benefit performance on tasks involving a search of semantic and associative networks under certain conditions. Therefore, we wished to determine whether this benefit of propranolol includes an effect on semantic fluency in autism. METHODS: A sample of 14 high-functioning adolescent and adult participants with autism and 14 matched controls were given letter and category word fluency tasks on 2 separate testing sessions; 1 test was given 60 minutes after the administration of 40 mg propranolol orally, and 1 test was given after placebo, administered in a double-blinded, counterbalanced manner. RESULTS: Participants with autism were significantly impaired compared with controls on both fluency tasks. Propranolol significantly improved performance on category fluency, but not letter fluency among autism participants. No drug effect was observed among controls. Expected drug effects on heart rate and blood pressure were observed in both the groups. CONCLUSIONS: Results are consistent with a selective beneficial effect of propranolol on flexibility of access to semantic and associative networks in autism, with no observed effect on phonological networks. Further study will be necessary to understand potential clinical implications of this finding.

Local vs. global approaches to reproducing the Rey Osterrieth Complex Figure by children, adolescents, and adults with high-functioning autism.

Individuals with autism have an atypical pattern of visual processing. Various studies have provided evidence that individuals with autism perceive the details of stimuli before the gestalt, the reverse of the typical pattern of visual processing. This study used the Rey Osterreith Complex Figure (ROCF) task and an objective scoring system to examine local/global processing approaches to its reproduction in 37 individuals diagnosed with high-functioning autism (HFA) compared to 49 age-, IQ-, and gender-matched typically developing controls (TD). The sample was divided into children (aged 8-14 years) and adolescents/adults (aged 15-47 years) to assess age effects. Results showed no difference in overall performance on the ROCF between HFA and TD children. TD participants displayed improved organizational and planning skills with age and a shift to global processing approaches, but there were no differences in performance between children and adolescents/adults with HFA. There was no evidence of enhanced local processing in either HFA group. These findings suggest that HFA individuals with average IQ scores do not have the clinically demonstrable evidence of the enhanced local processing thought to reflect increased local brain connectivity in more severely autistic individuals. The deficient global processing of the HFA adults reflects dependence of performance on impaired strategic problem-solving abilities, which has been demonstrated to result from under development of neural connectivity between visuo-spatial and frontal brain regions in HFA adults.