Jacob A. Burack

Deconstructing executive deficits among persons with autism: Implications for cognitive neuroscience

Individuals with autism demonstrate impairments on measures of executive function (EF) relative to typically developing comparison participants. EF is comprised of several processes including inhibition, working memory and set shifting that develop throughout the lifespan. Impairments in EF may appear early in development and persist, or may represent a more transient delay which resolves with time. Given the unevenness of the cognitive profile of persons with autism, understanding the development of EF poses methodological challenges. These issues include those related to matching measures and the choice of comparison participants to which the performance of persons with autism will be compared. In the current review, we attempt to break down the processes of inhibition, working memory and set shifting among persons with autism. We propose to do this within a developmental perspective that highlights how matching measures and comparison participants can affect the interpretation of research findings.

Perceptual Processing among High-functioning Persons with Autism

Two tasks were used to assess the processing of whole versus parts of objects in a group of high-functioning children and adolescents with autism (N = 11) and a comparison group of typically developing peers (N = 11) matched for chronological age and IQ. In the first task, only the children with autism showed a global advantage, and the two groups showed similar interference between levels. In the second task, the children with autism, despite longer RTs, showed similar performance to the comparison group with regard to the effect of goodness on visual parsing. Contrary to expectations based on the central coherence and hierarchisation deficit theories, these findings indicate intact holistic processing among persons with autism. The implications of these findings are discussed in relation to apparently discrepant evidence from other studies.

Enhanced Pure-Tone Pitch Discrimination among Persons with Autism but not Asperger Syndrome.

Persons with Autism spectrum disorders (ASD) display atypical perceptual processing in visual and auditory tasks. In vision, Bertone, Mottron, Jelenic, and Faubert (2005) found that enhanced and diminished visual processing is linked to the level of neural complexity required to process stimuli, as proposed in the neural complexity hypothesis. Based on these findings, Samson, Mottron, Jemel, Belin, and Ciocca (2006) proposed to extend the neural complexity hypothesis to the auditory modality. They hypothesized that persons with ASD should display enhanced performance for simple tones that are processed in primary auditory cortical regions, but diminished performance for complex tones that require additional processing in associative auditory regions, in comparison to typically developing individuals. To assess this hypothesis, we designed four auditory discrimination experiments targeting pitch, non-vocal and vocal timbre, and loudness. Stimuli consisted of spectro-temporally simple and complex tones. The participants were adolescents and young adults with autism, Asperger syndrome, and typical developmental histories, all with IQs in the normal range. Consistent with the neural complexity hypothesis and enhanced perceptual functioning model of ASD (Mottron, Dawson, Soulières, Hubert, & Burack, 2006), the participants with autism, but not with Asperger syndrome, displayed enhanced pitch discrimination for simple tones. However, no discrimination-thresholds differences were found between the participants with ASD and the typically developing persons across spectrally and temporally complex conditions. These findings indicate that enhanced pure-tone pitch discrimination may be a cognitive correlate of speech-delay among persons with ASD. However, auditory discrimination among this group does not appear to be directly contingent on the spectro-temporal complexity of the stimuli.

Developmental Changes of Autistic Symptoms

The study examined developmental changes in autistic symptoms retrospectively in a sample of 28 verbal children and adolescents with autism. Individuals with Asperger syndrome, PDD-NOS, and related medical conditions were not included in the study. We compared autistic symptoms present at the retrospective assessment and during the 4- to 5-year age period using the ADI-R. Our findings revealed a significant improvement in the three domains relevant for the diagnosis of autism, independent of age or IQ level. Improvement occurred in more symptoms from the social than the communication domain, and for more symptoms from the latter than the restricted interest and repetitive behavior domains. The finding that improvement was not linked to level of functioning and was found in individuals still positive for a diagnosis of autism suggests that improvement belongs to the ‘natural history’ of the handicap.

Veridical mapping in the development of exceptional autistic abilities.

Superior perception, peaks of ability, and savant skills are often observed in the autistic phenotype. The enhanced perceptual functioning model (Mottron et al., 2006a) emphasizes the increased role and autonomy of perceptual information processing in autistic cognition. Autistic abilities also involve enhanced pattern detection, which may develop through veridical mapping across isomorphic perceptual and non-perceptual structures (Mottron et al., 2009). In this paper, we elaborate veridical mapping as a specific mechanism which can explain the higher incidence of savant abilities, as well as other related phenomena, in autism. We contend that savant abilities such as hyperlexia, but also absolute pitch and synaesthesia, involve similar neurocognitive components, share the same structure and developmental course, and represent related ways by which the perceptual brain deals with objective structures under different conditions. Plausibly, these apparently different phenomena develop through a veridical mapping mechanism whereby perceptual information is coupled with homological data drawn from within or across isomorphic structures. The atypical neural connectivity characteristic of autism is consistent with a developmental predisposition to veridical mapping and the resulting high prevalence of savant abilities, absolute pitch, and synaesthesia in autism.

On Mosaics and Melting Pots: Conceptual Considerations of Comparison and Matching Strategies

Conceptual and pragmatic issues relevant to the study of persons with autism are addressed within the context of comparison groups and matching strategies. We argue that no choice of comparison group or matching strategy is perfect, but rather needs to be determined by specific research objectives and theoretical questions. Thus, strategies can differ between studies in which the goal is to delineate developmental profiles and those in which the focus is the study of a specific aspect of functioning. We promote the notion of a “mosaic,” rather than a “melting pot,” approach to science in which researchers communicate conservative and precise interpretations of empirical findings.

Social Perspective-Taking Skills in Maltreated Children and Adolescents

The primary goal of this study was to assess the ability of maltreated school-age children and adolescents to understand the thoughts, feelings, and points of view of others. Level of egocentrism and social perspective-taking coordination were assessed in a group of 49 maltreated and 49 demographically matched nonmaltreated children. Twenty-six elementary and 23 high school students in each group were individually interviewed and their responses to hypothetical interpersonal situations coded for egocentricity and level of perspective-taking ability. The findings revealed that maltreated children and adolescents were more egocentric and delayed in their social perspective-taking development than their nonmaltreated peers and that they reported lower levels of global self-worth. However, differences within the group of maltreated children and adolescents emerged with regard to negotiating novel relationships, as those with fewer internalizing or externalizing symptoms exhibited better skills in this area than their peers who displayed more symptoms.

Intact Covert Orienting to Peripheral Cues Among Children with Autism

The focus of the present study was to examine covert orienting responses to peripheral flash cues among children with autism in a situation where attentional processes were taxed by the presence of distractors in the visual field. Fourteen children with autism (MA = 6–7 years) were compared to their MA-matched peers without autism on a forced choice RT covert orienting paradigm. The task conditions varied with regard to the target location, the validity of the cue, and the presence or absence of distractors. The results showed no group differences as both children with autism and their MA-matched peers showed similar effects of cue validity and distractors. These findings are inconsistent with the view that orienting is generally impaired in children with autism.

Age Differences in Visual Search for Compound Patterns: Long- Versus Short-Range Grouping

Visual search for compound patterns was examined in observers aged 6, 8, 10, and 22 years. The main question was whether age-related improvement in search rate (response time slope over number of items) was different for patterns defined by short- versus long-range spatial relations. Perceptual access to each type of relation was varied by using elements of same contrast (easy to access) or mixed contrast (hard to access). The results showed large improvements with age in search rate for long-range targets; search rate for short-range targets was fairly constant across age. This pattern held regardless of whether perceptual access to a target was easy or hard, supporting the hypothesis that different processes are involved in perceptual grouping at these two levels. The results also point to important links between ontogenic and microgenic change in perception (H. Werner, 1948, 1957).

Constructions and Deconstructions of Risk, Resilience and Wellbeing: A Model for Understanding the Development of Aboriginal Adolescents

A developmental framework for understanding issues of risk, resilience, and wellness among Aboriginal adolescents in Canada and elsewhere is presented. As these constructs are not monolithic, simplistic linear risk models of a specific predictor to a specific outcome are inadequate to conceptually capture the complexities of real-life patterns. Accordingly, the conceptual focus is on ideal constructions of competence within the context of continually ongoing transactions in which the adolescents effect and are effected by the various layers and components of the environment. However, the pragmatics of empirical research necessitate simpler approaches in which outcomes are predicted from specific factors. Nonetheless, in keeping with the notion of the complexity of all individuals, competence and wellness are viewed within the framework of the ‘whole child’ across domains of academic success, behavioural competence and appropriateness, social adaptation, and emotional health within the context of the specific community. Although Aboriginal communities within Quebec, across Canada, the United States and elsewhere, differ considerably with regard to history, culture, language, and priorities for its youth, this approach allows for the universal application of a framework, for which specifics can be modified in relation to the unique and changing aspects of societies, communities, and the individuals within.