The profile of memory function in children with autism

Association between obesity-related gene FTO and ADHD

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is an etiologically complex heterogeneous behavioral disorder. Several studies have reported that ADHD subjects are more likely to be overweight/obese and that this comorbidity may be due to shared genetic factors. The objective of this study is to explore the association between ADHD and FTO, a gene strongly associated with obesity in genome-wide studies.

DESIGN AND METHODS

One tag SNP (single-nucleotide polymorphism, rs8050136, risk allele A) in the FTO gene was selected and its association with ADHD was tested. Family-based association tests (FBATs) were conducted with the categorical diagnosis of ADHD as well as behavioral and cognitive phenotypes related to ADHD. Furthermore, stratified FBAT analyses based on maternal smoking during pregnancy (MSDP) status were conducted.

RESULTS

Statistically significant associations were observed between rs8050136 and several of the traits tested in the total sample. These associations were stronger when the analysis was restricted to children who were not exposed to MSDP.

CONCLUSIONS

These exploratory results suggest the involvement of the FTO SNP rs8050136 in modulating the risk for ADHD, particularly in those children who were not exposed to MSDP. If confirmed, they may explain, at least in part, the complex links between obesity and ADHD.

Common Cognitive Deficits in Children With Attention-Deficit/Hyperactivity Disorder and Autism

Cognitive deficits in working memory (WM) are characteristic features of Attention-Deficit/Hyperactivity Disorder (ADHD) and autism. However, few studies have investigated cognitive deficits using a wide range of cognitive measures. We compared children with ADHD ( n = 49) and autism ( n = 33) with a demographically matched control group ( n = 79) on a multidimensional battery of cognitive ability. Results confirmed previous research that both groups were characterized by deficits in WM. However, results also suggest verbal WM measures were better predictors than nonverbal WM measures. In addition, measures of visual-motor integration are equally discriminating of children with ADHD and autism from a matched control group. In all, 81% discrimination accuracy was obtained using only WM and visual-motor integration measures. Demonstrated shared deficits in WM and visual-motor integration are explained based on proposed neurological mechanisms common across the two disorders. Clinical implications are discussed.

Event narratives in 11-14 year olds with autistic spectrum disorder

BACKGROUND

Children with autistic spectrum disorder (ASD) are known to have difficulties in narrative language and especially with use of evaluative enrichment devices. However, little is known about their production of event narratives.

AIMS

To establish if children with ASD differ from typically developing peers in their production of general and specific event narratives, and, if so, how this might be affected by levels of oral language.

METHODS & PROCEDURES

Performance on general and specific event narrative tasks of 27 high-functioning children with ASD, aged 11-14 years, was compared with that of language- and age-matched groups of typically developing children. Narratives were coded for structural and evaluative language measures.

OUTCOMES & RESULTS

The general and specific event narratives of the ASD group differed from those of both comparison groups in structural language measures. They were shorter, contained fewer different word roots and had shorter mean length of utterances. In evaluative measures they differed from those of the typically developing age match group but not the younger language match group in the number of causal statements made in both event conditions, and in mental state references and evaluative devices in the specific event narrative condition.

CONCLUSIONS & IMPLICATIONS

Children with ASD display specific difficulties with the use of grammar and vocabulary in event narratives which cannot be explained in terms of language levels. However, the use of evaluative devices was commensurate with oral language levels. Implications for intervention are discussed.

Predicting literacy in children with a high-functioning autism spectrum disorder

The most commonly reported reading profile for children with a high-functioning autism spectrum disorder (HFASD) is one of intact decoding combined with reduced reading comprehension. Whether or not the variables that predict decoding and reading comprehension for children with a HFASD are exactly the same as those identified for a non-ASD population is unknown. Therefore, the ability of cognition, phonological processing, oral language, and vision to predict decoding and reading comprehension was investigated. Regression analysis revealed that cognition, phonological processing, and syntax predicted decoding and reading comprehension for the HFASD and non-ASD groups. One notable difference was that semantics predicted literacy for the non-ASD children but not their HFASD peers.

Working memory deficits in high-functioning adolescents with autism spectrum disorders: neuropsychological and neuroimaging correlates

Working memory is a temporary storage system under attentional control. It is believed to play a central role in online processing of complex cognitive information and may also play a role in social cognition and interpersonal interactions. Adolescents with a disorder on the autism spectrum display problems in precisely these domains. Social impairments, communication difficulties, and repetitive interests and activities are core domains of autism spectrum disorders (ASD), and executive function problems are often seen throughout the spectrum. As the main cognitive theories of ASD, including the theory of mind deficit hypotheses, weak central coherence account, and the executive dysfunction theory, still fail to explain the broad spectrum of symptoms, a new perspective on the etiology of ASD is needed. Deficits in working memory are central to many theories of psychopathology, and are generally linked to frontal-lobe dysfunction. This article will review neuropsychological and (functional) brain imaging studies on working memory in adolescents with ASD. Although still disputed, it is concluded that within the working memory system specific problems of spatial working memory are often seen in adolescents with ASD. These problems increase when information is more complex and greater demands on working memory are made. Neuroimaging studies indicate a more global working memory processing or connectivity deficiency, rather than a focused deficit in the prefrontal cortex. More research is needed to relate these working memory difficulties and neuroimaging results in ASD to the behavioral difficulties as seen in individuals with a disorder on the autism spectrum.

Cognitive flexibility in ASD; task switching with emotional faces

Children with autism spectrum disorders (ASDs) show daily cognitive flexibility deficits, but laboratory data are unconvincing. The current study aimed to bridge this gap. Thirty-one children with ASD (8–12 years) and 31 age- and IQ-matched typically developing children performed a gender emotion switch task. Unannounced switches and complex stimuli (emotional faces) improved ecological validity; minimal working memory-load prevented bias in the findings. Overall performance did not differ between groups, but in a part of the ASD group performance was slow and inaccurate. Moreover, within the ASD group switching from emotion to gender trials was slower than vice versa. Children with ASD do not show difficulties on an ecological valid switch task, but have difficulty disengaging from an emotional task set.

Abstract spatial reasoning as an autistic strength

Autistic individuals typically excel on spatial tests that measure abstract reasoning, such as the Block Design subtest on intelligence test batteries and the Raven’s Progressive Matrices nonverbal test of intelligence. Such well-replicated findings suggest that abstract spatial processing is a relative and perhaps absolute strength of autistic individuals. However, previous studies have not systematically varied reasoning level – concrete vs. abstract – and test domain – spatial vs. numerical vs. verbal, which the current study did. Autistic participants (N = 72) and non-autistic participants (N = 72) completed a battery of 12 tests that varied by reasoning level (concrete vs. abstract) and domain (spatial vs. numerical vs. verbal). Autistic participants outperformed non-autistic participants on abstract spatial tests. Non-autistic participants did not outperform autistic participants on any of the three domains (spatial, numerical, and verbal) or at either of the two reasoning levels (concrete and abstract), suggesting similarity in abilities between autistic and non-autistic individuals, with abstract spatial reasoning as an autistic strength.

An examination of iconic memory in children with autism spectrum disorders

Iconic memory is the ability to accurately recall a number of items after a very brief visual exposure. Previous research has examined these capabilities in typically developing (TD) children and individuals with intellectual disabilities (ID); however, there is limited research on these abilities in children with Autism Spectrum Disorders (ASD). Twenty-one TD and eighteen ASD children were presented with circular visual arrays of letters for 100 ms and were asked to recall as many letters as possible or a single letter that was cued for recall. Groups did not differ in the number of items recalled, the rate of information decay, or speed of information processing. These findings suggest that iconic memory is an intact skill for children with ASD, a result that has implications for subsequent information processing.

Social working memory: neurocognitive networks and directions for future research

Navigating the social world requires the ability to maintain and manipulate information about people's beliefs, traits, and mental states. We characterize this capacity as social working memory (SWM). To date, very little research has explored this phenomenon, in part because of the assumption that general working memory systems would support working memory for social information. Various lines of research, however, suggest that social cognitive processing relies on a neurocognitive network (i.e., the "mentalizing network") that is functionally distinct from, and considered antagonistic with, the canonical working memory network. Here, we review evidence suggesting that demanding social cognition requires SWM and that both the mentalizing and canonical working memory neurocognitive networks support SWM. The neural data run counter to the common finding of parametric decreases in mentalizing regions as a function of working memory demand and suggest that the mentalizing network can support demanding cognition, when it is demanding social cognition. Implications for individual differences in social cognition and pathologies of social cognition are discussed.

Individual differences in autistic trait load in the general population predict visual working memory performance

Prior studies have reported instances of both intact and impaired working memory (WM) performance in people with autism spectrum disorder (ASD). In order to investigate the relation between autistic traits that extend into the normal population and WM, 104 normal college-aged students who varied in their levels of autistic traits were tested. The loading of ASD-associated traits in the normal population leads to differing predictions about WM performance. ASD traits related to a local processing style (or "attention to detail") might enhance WM while ASD-associated traits related to difficulty switching attention and reorienting focus (or "social interaction") might impair WM performance. To assess these predictions, participants filled out the Autism Spectrum Quotient (AQ) and performed a working memory task with both visual and verbal variants. AQ scores were then broken into "attention to detail" and "social interaction" factors, as proposed by Hoekstra and colleagues. The results showed that AQ scores did not predict verbal WM performance but they did predict visual WM performance. The social interaction and attention to detail factors of the AQ had opposing relationships with visual WM performance: A higher level of social difficulty was associated with significantly poorer visual WM performance while a higher level of attention to detail was associated with enhanced visual WM performance. Further investigation of the relation between AQ and WM using the original five-factor model proposed by Baron-Cohen and colleagues (2001) revealed an association between impoverished imagination and visual WM overall.

Working memory, language skills, and autism symptomatology

While many studies have reported working memory (WM) impairments in autism spectrum disorders, others do not. Sample characteristics, WM domain, and task complexity likely contribute to these discrepancies. Although deficits in visuospatial WM have been more consistently documented, there is much controversy regarding verbal WM in autism. The goal of the current study was to explore visuospatial and verbal WM in a well-controlled sample of children with high-functioning autism (HFA) and typical development. Individuals ages 9–17 with HFA (n = 18) and typical development (n = 18), were carefully matched on gender, age, IQ, and language, and were administered a series of standardized visuospatial and verbal WM tasks. The HFA group displayed significant impairment across WM domains. No differences in performance were noted across WM tasks for either the HFA or typically developing groups. Over and above nonverbal cognition, WM abilities accounted for significant variance in language skills and symptom severity. The current study suggests broad WM limitations in HFA. We further suggest that deficits in verbal WM are observed in more complex tasks, as well as in simpler tasks, such as phonological WM. Increased task complexity and linguistic demands may influence WM abilities.

Intelligence and cognition in a child with high functioning autism

Intelligence is assessed for ruling out mental retardation and to find out the relative cognitive strengths in autism. Of special interest is to know the nature of intelligence and cognition in high functioning autism. But very little is known how the assessments are carried given the deficits in communication, socialization in autism. This cross-sectional study aims to describe the nature of intelligence and cognition in a child with HFA and drawing implications for assessment in the Indian setting. Results indicate that there is no evidence for superior crystallized intelligence in HFA, though a jagged profile could be expected both across and within cognitive domains.

Visual Scanning Patterns during the Dimensional Change Card Sorting Task in Children with Autism Spectrum Disorder

Impaired cognitive flexibility in children with autism spectrum disorder (ASD) has been reported in previous literature. The present study explored ASD children's visual scanning patterns during the Dimensional Change Card Sorting (DCCS) task using eye-tracking technique. ASD and typical developing (TD) children completed the standardized DCCS procedure on the computer while their eye movements were tracked. Behavioral results confirmed previous findings on ASD children's deficits in executive function. ASD children's visual scanning patterns also showed some specific underlying processes in the DCCS task compared to TD children. For example, ASD children looked shorter at the correct card in the postswitch phase and spent longer time at blank areas than TD children did. ASD children did not show a bias to the color dimension as TD children did. The correlations between the behavioral performance and eye moments were also discussed.

Consensus paper: pathological role of the cerebellum in autism

There has been significant advancement in various aspects of scientific knowledge concerning the role of cerebellum in the etiopathogenesis of autism. In the current consensus paper, we will observe the diversity of opinions regarding the involvement of this important site in the pathology of autism. Recent emergent findings in literature related to cerebellar involvement in autism are discussed, including: cerebellar pathology, cerebellar imaging and symptom expression in autism, cerebellar genetics, cerebellar immune function, oxidative stress and mitochondrial dysfunction, GABAergic and glutamatergic systems, cholinergic, dopaminergic, serotonergic, and oxytocin-related changes in autism, motor control and cognitive deficits, cerebellar coordination of movements and cognition, gene-environment interactions, therapeutics in autism, and relevant animal models of autism. Points of consensus include presence of abnormal cerebellar anatomy, abnormal neurotransmitter systems, oxidative stress, cerebellar motor and cognitive deficits, and neuroinflammation in subjects with autism. Undefined areas or areas requiring further investigation include lack of treatment options for core symptoms of autism, vermal hypoplasia, and other vermal abnormalities as a consistent feature of autism, mechanisms underlying cerebellar contributions to cognition, and unknown mechanisms underlying neuroinflammation.

Autism and the cognitive processing triad: a case for revising the criteria in the diagnostic and statistical manual

TOPIC

The next iteration of the Diagnostic and Statistical Manual of Mental Disorders is due for release in May 2013. The current diagnostic criteria for autism are based on a behavioral triad of impairment, which has been helpful for diagnosis and identifying the need for intervention, but is not useful with regard to developing interventions. Revised diagnostic criteria are needed to better inform research and therapeutic intervention.

PURPOSE

This article examines the research underpinning the behavioral triad of impairment to consider alternative explanations and a more useful framing for diagnosis and intervention.

SOURCES

Contemporary research and literature on autism were used in this study.

CONCLUSIONS

It is proposed that the cognitive processing triad of impaired abstraction, impaired theory of mind, and impaired linguistic processing become the triad of impairment for autism in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders. These are investigable at the diagnostic level and can usefully inform intervention. Further, in addressing the debate on whether restrictive and repetitive behavior should remain central to diagnosis or be replaced by a deficit in imagination, the authors argue that both behavioral manifestations are underpinned by impaired abstraction.

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.

Memory in ASD: have we been barking up the wrong tree?

In this theoretical note, possible neural causes of episodic memory impairment in individuals with ASD and currently normal intellectual and linguistic function are considered. The neural causes most commonly argued for are hippocampal or prefrontal cortex dysfunction, associated with impaired neural connectivity. It is argued here that a hippocampal dysfunction hypothesis is weakened by differences in cued recall and paired associate learning in individuals with ASD compared with individuals with developmental or acquired hippocampus-related amnesia, and that recent findings on patients with posterior parietal lesions (PPC) offer a better fit with the dissociation between free and cued recall observed in ASD. The PPC forms part of the default system subserving mindreading, among other functions, and an association between PPC dysfunction and memory impairment in ASD is consistent with recent suggestions that neural disconnectivity within the default system underlies behaviours diagnostic of ASD.

Whose memories are they and where do they go? Problems surrounding internalization in children on the autistic spectrum

Recent work in neuroscience has highlighted the contrast between 'procedural' memory for bodily experiences and skills, which is unconscious though unrepressed, and verbalizable, 'declarative' memory, which includes autobiographical memory. Autobiographical memory is weak in people with autistic spectrum disorder, who frequently turn to self-generated sensations for reassurance that they continue to exist. The author suggests that, instead of internalizing shared experiences leading to growth, children with autism can feel that they add to themselves by taking over the qualities of others through the 'annexation' of physical properties that leads to a damaged object and can trigger a particular sort of negative therapeutic reaction. Clinical illustrations drawn from the treatment of two children on the autistic spectrum illustrate some ramifications of these processes in relation to the sense of a separate identity and the capacity to access memories.

Evidence for social working memory from a parametric functional MRI study

Keeping track of various amounts of social cognitive information, including people's mental states, traits, and relationships, is fundamental to navigating social interactions. However, to date, no research has examined which brain regions support variable amounts of social information processing ("social load"). We developed a social working memory paradigm to examine the brain networks sensitive to social load. Two networks showed linear increases in activation as a function of increasing social load: the medial frontoparietal regions implicated in social cognition and the lateral frontoparietal system implicated in nonsocial forms of working memory. Of these networks, only load-dependent medial frontoparietal activity was associated with individual differences in social cognitive ability (trait perspective-taking). Although past studies of nonsocial load have uniformly found medial frontoparietal activity decreases with increasing task demands, the current study demonstrates these regions do support increasing mental effort when such effort engages social cognition. Implications for the etiology of clinical disorders that implicate social functioning and potential interventions are discussed.

Thinking in Pictures as a cognitive account of autism

We analyze the hypothesis that some individuals on the autism spectrum may use visual mental representations and processes to perform certain tasks that typically developing individuals perform verbally. We present a framework for interpreting empirical evidence related to this "Thinking in Pictures" hypothesis and then provide comprehensive reviews of data from several different cognitive tasks, including the n-back task, serial recall, dual task studies, Raven's Progressive Matrices, semantic processing, false belief tasks, visual search, spatial recall, and visual recall. We also discuss the relationships between the Thinking in Pictures hypothesis and other cognitive theories of autism including Mindblindness, Executive Dysfunction, Weak Central Coherence, and Enhanced Perceptual Functioning.

Regional differences in grey and white matter in children and adults with autism spectrum disorders: an activation likelihood estimate (ALE) meta-analysis

Structural alterations in brain morphology have been inconsistently reported in children compared to adults with autism spectrum disorder (ASD). We assessed these differences by performing meta-analysis on the data from 19 voxel-based morphometry studies. Common findings across the age groups were grey matter reduction in left putamen and medial prefrontal cortex (mPFC) and grey matter increases in the lateral PFC, while white matter decreases were seen mainly in the children in frontostriatal pathways. In the ASD sample, children/adolescents were more likely than adults to have increased grey matter in bilateral fusiform gyrus, right cingulate and insula. Results show that clear maturational differences exist in social cognition and limbic processing regions only in children/adolescents and not in adults with ASD, and may underlie the emotional regulation that improves with age in this population.

Memory functioning in children and adolescents with autism

OBJECTIVE

Memory functioning in children and adolescents ages 5-19 with autism (n = 50) and typically developing controls (n = 36) was assessed using a clinical assessment battery, the Test of Memory and Learning (TOMAL).

METHOD

Participant groups were statistically comparable in age, nonverbal IQ, handedness, and head circumference, and were administered the TOMAL.

RESULTS

Test performance on the TOMAL demonstrated broad differences in memory functioning in the autism group, across multiple task formats, including verbal and nonverbal, immediate and delayed, attention and concentration, sequential recall, free recall, associative recall, and multiple-trial learning memory. All index and nearly all subtest differences remained significant even after comparing a subset of the autism group (n = 36) and controls that were matched for verbal IQ (p > .05). However, retention of previously remembered information after a delay was similar in autism and controls.

CONCLUSIONS

These findings indicate that performance on measures of episodic memory is broadly reduced in autism, and support the conclusion that information encoding and organization, possibly due to inefficient cognitive processing strategies, rather than storage and retrieval, are the primary factors that limit memory performance in autism.

Context reinstatement effects on eyewitness memory in autism spectrum disorder

The Cognitive Interview is among the most widely accepted forms of police interviewing techniques; however, it is ineffective for witnesses with autism spectrum disorder (ASD). One of its main components involves mentally reinstating the internal and external context that was experienced at encoding. We report evidence showing that it is the mental reinstatement instructions in the absence of any physical cues that individuals with ASD find difficult. In more supported conditions where they physically return to the same environment in which they learnt the material, they recall as much as their typical counterparts. Our findings indicate that recall in ASD is aided by context, but only when supported by the physical environment. These findings have important implications for investigative interviewing procedures for witnesses with ASD.

Verbal problem-solving in autism spectrum disorders: a problem of plan construction?

Children with autism spectrum disorders (ASD) adopt less efficient strategies than typically developing controls (TD) on verbal problem-solving tests such as the Twenty Questions Task. This study examined the hypotheses that this can be explained by differences in (i) planning processes or (ii) selective attention. Twenty-two children with ASD and 21 TD controls matched for age (M(age) = 13:7) and cognitive ability (M(FSIQ) = 96.42) were tested on an adapted version of Twenty Questions and two planning tasks. ASD participants could recognize effective questions as well as TD participants on a forced-choice question discrimination task, but were observed to construct plans that were significantly less efficient. ASD performance was also specifically reduced when items could not be physically removed from the testing array, although this effect could be ameliorated by keeping a written record of participant questions during search. These findings indicate that ASD participants are sensitive to the within-task executive demands of Twenty Questions, but that their inefficiency in strategy relates to planning processes and question selection pretask. The implications for understanding ASD problem-solving skills and their impact on everyday functioning are discussed.

Functional and dysfunctional brain circuits underlying emotional processing of music in autism spectrum disorders

Despite intersubject variability, dramatic impairments of socio-communicative skills are core features of autistic spectrum disorder (ASD). A deficit in the ability to express and understand emotions has often been hypothesized to be an important correlate of such impairments. Little is known about individuals with ASD's ability to sense emotions conveyed by nonsocial stimuli such as music. Music has been found to be capable of evoking and conveying strong and consistent positive and negative emotions in healthy subjects. The ability to process perceptual and emotional aspects of music seems to be maintained in ASD. Individuals with ASD and neurotypical (NT) controls underwent a single functional magnetic resonance imaging (fMRI) session while processing happy and sad music excerpts. Overall, fMRI results indicated that while listening to both happy and sad music, individuals with ASD activated cortical and subcortical brain regions known to be involved in emotion processing and reward. A comparison of ASD participants with NT individuals demonstrated decreased brain activity in the premotor area and in the left anterior insula, especially in response to happy music excerpts. Our findings shed new light on the neurobiological correlates of preserved and altered emotional processing in ASD.

Abstract reasoning and friendship in high functioning preadolescents with autism spectrum disorders

To investigate the relationship between cognitive and social functioning, 20 Israeli individuals with HFASD aged 8-12 and 22 age, maternal education, and receptive vocabulary-matched preadolescents with typical development (TYP) came to the lab with a close friend. Measures of abstract reasoning, friendship quality, and dyadic interaction during a play session were obtained. As hypothesized, individuals with HFASD were significantly impaired in abstract reasoning, and there were significant group differences in friend and observer reports of friendship quality. There also was consistency in reports between friends. Two factors-"relationship appearance" and "relationship quality" described positive aspects of the relationships. Disability status and age related to relationship appearance. Proband abstract reasoning was related to relationship quality.

The intense world theory - a unifying theory of the neurobiology of autism

Autism covers a wide spectrum of disorders for which there are many views, hypotheses and theories. Here we propose a unifying theory of autism, the Intense World Theory. The proposed neuropathology is hyper-functioning of local neural microcircuits, best characterized by hyper-reactivity and hyper-plasticity. Such hyper-functional microcircuits are speculated to become autonomous and memory trapped leading to the core cognitive consequences of hyper-perception, hyper-attention, hyper-memory and hyper-emotionality. The theory is centered on the neocortex and the amygdala, but could potentially be applied to all brain regions. The severity on each axis depends on the severity of the molecular syndrome expressed in different brain regions, which could uniquely shape the repertoire of symptoms of an autistic child. The progression of the disorder is proposed to be driven by overly strong reactions to experiences that drive the brain to a hyper-preference and overly selective state, which becomes more extreme with each new experience and may be particularly accelerated by emotionally charged experiences and trauma. This may lead to obsessively detailed information processing of fragments of the world and an involuntarily and systematic decoupling of the autist from what becomes a painfully intense world. The autistic is proposed to become trapped in a limited, but highly secure internal world with minimal extremes and surprises. We present the key studies that support this theory of autism, show how this theory can better explain past findings, and how it could resolve apparently conflicting data and interpretations. The theory also makes further predictions from the molecular to the behavioral levels, provides a treatment strategy and presents its own falsifying hypothesis.

Working memory in early-school-age children with Asperger's syndrome

Using a battery of working memory span tasks and n-back tasks, this study aimed to explore working memory functions in early-school-age children with Asperger's syndrome (AS). Twelve children with AS and 29 healthy children matched on age and IQ were recruited. Results showed: (a) children with AS performed better in digit and word recall tasks, but worse in block recall task and variant-visual-patterns test; (b) children with AS took longer time in most conditions of n-back tasks, and showed larger effects of task load. These findings indicated imbalance of working memory development in AS children: they had advantage in the phonological loop storing, but disadvantage in the visuospatial sketchpad storing, and partial deficit in central executive.

Recognizing faces based on inferred traits in autism spectrum disorders

Recent findings indicate that individuals with autism spectrum disorders (ASD) could, surprisingly, infer traits from behavioural descriptions. Now we need to know whether or not individuals with ASD are able to use trait information to identify people by their faces. In this study participants with and without ASD were presented with pairs of faces each accompanied by a sentence. One sentence allowed a trait to be inferred (e.g. 'This is Ross who smiled and said hello to everyone at the party.') and one allowed a fact to be inferred (e.g. 'This is Ben who has to bend down to enter most doors.'). Subsequently, the same face stimuli were presented with a single descriptive trait, fact or name cue (e.g. friendly or tall and Ross or Ben respectively in the above examples). Participants had to choose which of the faces best related to the cue word. Participants with ASD performed surprisingly well in associating traits, facts, and names to the appropriate person significantly above what would be expected by chance. Indeed, they performed as well as participants without ASD.

Teaching children with autism to read for meaning: challenges and possibilities

The purpose of this literature review is to examine what makes reading for understanding especially challenging for children on the autism spectrum, most of whom are skilled at decoding and less skilled at comprehension. This paper first summarizes the research on reading comprehension with a focus on the cognitive skills and processes that are involved in gaining meaning from text and then reviews studies of reading comprehension deficits in children on the spectrum. The paper concludes with a review of reading comprehension interventions for children on the spectrum. These children can especially benefit from interventions addressing particular cognitive processes, such as locating antecedent events, generating and answering questions, locating referents, and rereading to repair understanding.

Discriminant analysis for repeated measures data: a review

Discriminant analysis (DA) encompasses procedures for classifying observations into groups (i.e., predictive discriminative analysis) and describing the relative importance of variables for distinguishing amongst groups (i.e., descriptive discriminative analysis). In recent years, a number of developments have occurred in DA procedures for the analysis of data from repeated measures designs. Specifically, DA procedures have been developed for repeated measures data characterized by missing observations and/or unbalanced measurement occasions, as well as high-dimensional data in which measurements are collected repeatedly on two or more variables. This paper reviews the literature on DA procedures for univariate and multivariate repeated measures data, focusing on covariance pattern and linear mixed-effects models. A numeric example illustrates their implementation using SAS software.

The mind of the mnemonists: an MEG and neuropsychological study of autistic memory savants

About 10% of autistic individuals exhibit some form of islets of abilities in the face of serious intellectual or mental disability ("savant syndrome"). The aim of this study was to investigate brain mechanisms in a sample of autistic subjects with outstanding memory. We investigated seven mnemonist savants with high-functioning autism spectrum disorder and seven matched controls with 151-channel whole-head magnetencephalography in a continuous old-new paradigm. They were presented with 300 pseudowords and 300 shapes and had to indicate by button press, whether the presented stimulus had been shown before. Unexpectedly, mnemonist savants did not perform better than controls, but were outperformed in the recognition of pseudowords. Accordingly, event-related magnetic fields elicited by pseudowords showed widespread old-new effects in controls, but not in savants. A source analysis of its early components revealed right occipital activation in savants, but left parietal activation in controls. This might be related to a visual processing style in mnemonist savants that proved to be inefficient in this task. During the possibly familiarity-based recognition of shapes, there were earlier and more widespread bilateral old-new effects in mnemonist savants, what might reflect their experience with figural material. In a neuropsychological test battery, mnemonist savants performed comparably to autistic people without special memory skills. However, a different factor structure of these tests pointed to a different organization of memory in mnemonist savants compared to controls that is characterized by its relative independence of general intelligence.

Visuospatial short-term memory explains deficits in tower task planning in high-functioning children with autism spectrum disorder

Previous findings on planning abilities in individuals with high-functioning autism spectrum disorder (HFA) are inconsistent. Exploring possible reasons for these mixed findings, the current study investigated the involvement of memory in planning performance in 15 children with HFA and 17 typically developing controls. In addition to planning abilities (measured with the Tower of London), short-term memory and delayed recall for verbal as well as visuospatial material were assessed. Findings suggest that particularly reduced efficiency in visuospatial short-term memory is associated with Tower task planning deficits in children with HFA.

The Medial Prefrontal Cortex and Integration in Autism

This article offers a unifying theoretical interpretation of known abnormalities in people with autism spectrum disorders (ASDs) in four psychological domains, namely emotion, memory, sensation-perception, and motor skills. It proposes that in all four domains three levels of processing can be identified: a basic level, an integrative level, and a “logical” or higher-order level. It also notes that in typically developing people, there is evidence that the integrative level is subserved by subregions of the medial prefrontal cortex. The major argument of the article is to propose and argue that the integrative level in all four domains is responsible for common atypicalities in people with ASDs.

Negative emotion does not enhance recall skills in adults with autistic spectrum disorders

Recent empirical findings suggest a significant influence of emotion on memory processes. Surprisingly, although emotion-processing difficulties appear to be a hallmark feature in autism spectrum disorders (ASD), their impact on higher-level cognitive functions, such as memory, has not been directly studied in this population. The aim of this study was to address this issue by assessing whether the emotional valence of visual scenes affects recall skills in high-functioning individuals with ASD. To this purpose, their recall performance of neutral and emotional pictures was compared with that of typically developing adults (control group). Results revealed that while typically developing individuals showed enhanced recall skills for negative relative to positive and neutral pictures, individuals with ASD recalled the neutral pictures as well as the emotional ones. Findings of this study thus point to reduced influence of emotion on memory processes in ASD than in typically developing individuals, possibly owing to amygdala dysfunctions.

Aberrant functional connectivity in autism: evidence from low-frequency BOLD signal fluctuations

A number of recent studies have examined functional connectivity in individuals with Autism Spectrum Disorders (ASD), generally converging on the finding of reduced interregional coordination, or underconnectivity. Underconnectivity has been reported between many brain regions and across a range of cognitive tasks, and has been proposed to underlie behavioral and cognitive impairments associated with ASD. The current study employed functional connectivity MRI (fcMRI) to examine interregional correlations of low-frequency BOLD signal fluctuations in 10 high-functioning participants with ASD and 10 typically developing control participants. Whole-brain connectivity with three seed regions of interest (left middle frontal, left superior parietal, and left middle occipital cortex) was evaluated using fMRI datasets acquired during performance of a source recognition task. While fcMRI patterns were found to be largely similar across the two groups, including many common areas, effects for the ASD group were generally more extensive. These findings, although inconsistent with generalized underconnectivity in ASD, are compatible with a model of aberrant connectivity in which the nature of connectivity disturbance (i.e., increased or reduced) may vary by region. Taking into consideration methodological factors that might influence measured fcMRI effects, we suggest that ASD is associated with an inefficiency in optimizing network connections to achieve task performance.

Understanding executive control in autism spectrum disorders in the lab and in the real world

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 whether 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.

Verbal Working Memory and Story Retelling in School-Age Children With Autism

Purpose

This study examined verbal working memory and language ability in 15 school-age children with autism using 3 verbal working memory tasks and 1 story recall task.

Method

Three measures of verbal working memory—nonword repetition, memory for digits span, and sentence imitation—were given to children with autism and age-matched controls. Verbal working memory measures were chosen to reflect increasing levels of cognitive–linguistic complexity. Story retelling was measured using The Renfrew Bus Story (J. Cowley & C. Glasgow, 1994) and was scored for the percentage of propositions recalled and the average utterance length.

Results

A profile of verbal working memory deficits was seen in children with autism, with poorer performance on more complex verbal memory tasks. Performance on the 3 verbal memory tasks was independent of articulation ability. For the group with autism, receptive vocabulary was associated with sentence imitation and story recall but not with nonword repetition or digits span. Sentence imitation was related to story recall, but the relationship disappeared when the effect of vocabulary was removed.

Conclusions

Vocabulary and language processing demands affect the performance of children with autism on tasks of verbal memory and story retelling. Results are viewed within a connectionist framework of verbal working memory .