Matching strategies in cognitive research with individuals with high-functioning autism: current practices, instrument biases, and recommendations

Concurrent Validity of the WISC-IV and DAS-II in Children With Autism Spectrum Disorder

Cognitive assessments are used for a variety of research and clinical purposes in children with autism spectrum disorder (ASD). This study establishes concurrent validity of the Wechsler Intelligence Scales for Children–fourth edition (WISC-IV) and Differential Ability Scales–second edition (DAS-II) in a sample of children with ASD with a broad range of cognitive abilities. Participants achieved significantly higher overall scores on the DAS-II and nearly half the sample achieved a higher classification label on the DAS-II. The difference between overall scores is suggested to be attributable to a relative weakness in processing speed, which is assessed on the WISC-IV but not the DAS-II. Autistic symptomatology was not associated with cognitive scores, while adaptive behavior was positively associated. Neither was associated with the magnitude of difference between overall scores. Choice of assessment should be considered carefully given the systematic differences in overall scores produced in this population.

Autism and EMF? Plausibility of a pathophysiological link - Part I

Although autism spectrum conditions (ASCs) are defined behaviorally, they also involve multileveled disturbances of underlying biology that find striking parallels in the physiological impacts of electromagnetic frequency and radiofrequency exposures (EMF/RFR). Part I of this paper will review the critical contributions pathophysiology may make to the etiology, pathogenesis and ongoing generation of core features of ASCs. We will review pathophysiological damage to core cellular processes that are associated both with ASCs and with biological effects of EMF/RFR exposures that contribute to chronically disrupted homeostasis. Many studies of people with ASCs have identified oxidative stress and evidence of free radical damage, cellular stress proteins, and deficiencies of antioxidants such as glutathione. Elevated intracellular calcium in ASCs may be due to genetics or may be downstream of inflammation or environmental exposures. Cell membrane lipids may be peroxidized, mitochondria may be dysfunctional, and various kinds of immune system disturbances are common. Brain oxidative stress and inflammation as well as measures consistent with blood-brain barrier and brain perfusion compromise have been documented. Part II of this paper will review how behaviors in ASCs may emerge from alterations of electrophysiological oscillatory synchronization, how EMF/RFR could contribute to these by de-tuning the organism, and policy implications of these vulnerabilities. Changes in brain and autonomic nervous system electrophysiological function and sensory processing predominate, seizures are common, and sleep disruption is close to universal. All of these phenomena also occur with EMF/RFR exposure that can add to system overload ('allostatic load') in ASCs by increasing risk, and worsening challenging biological problems and symptoms; conversely, reducing exposure might ameliorate symptoms of ASCs by reducing obstruction of physiological repair. Various vital but vulnerable mechanisms such as calcium channels may be disrupted by environmental agents, various genes associated with autism or the interaction of both. With dramatic increases in reported ASCs that are coincident in time with the deployment of wireless technologies, we need aggressive investigation of potential ASC - EMF/RFR links. The evidence is sufficient to warrant new public exposure standards benchmarked to low-intensity (non-thermal) exposure levels now known to be biologically disruptive, and strong, interim precautionary practices are advocated.

Statistical persistence and timing characteristics of repetitive circle drawing in children with ASD

OBJECTIVE

Standardized tests to assess movement difficulties in autism spectrum disorder (ASD) evaluate motor output, but do not provide information about underlying dynamics. The objective of this research is to study the statistical persistence and temporal dynamics of a circle drawing task in children with ASD.

METHODS

For this study 15 children diagnosed with ASD, aged 4-8 years, were asked to draw circles under various conditions using a computerized tablet. We then assessed fractal dynamics and global temporal dynamics (mean and coefficient of variation) and compared these quantities to those of typically developing (TD) controls.

RESULTS

No difference in statistical persistence was found between children with ASD and TD children. Temporal measures showed increased variability in the ASD population in the discontinuous task.

CONCLUSION

Results support the hypothesis that children with ASD have an intact ability to consistently produce continuous movements, but increased variability in production of discontinuous movements.

Theory of Mind Deficit versus Faulty Procedural Memory in Autism Spectrum Disorders

Individuals with autism spectrum disorders (ASD) have impairments in social interaction, communicative capacity, and behavioral flexibility (core triad). Three major cognitive theories (theory of mind deficit, weak central coherence, and executive dysfunction) seem to explain many of these impairments. Currently, however, the empathizing-systemizing (a newer version of the theory of mind deficit account) and mnesic imbalance theories are the only ones that attempt to explain all these core triadic symptoms of ASD On the other hand, theory of mind deficit in empathizing-systemizing theory is the most influential account for ASD, but its counterpart in the mnesic imbalance theory, faulty procedural memory, seems to occur earlier in development; consequently, this might be a better solution to the problem of the etiology of ASD, if it truly meets the precedence criterion. Hence, in the present paper I review the reasoning in favor of the theory of mind deficit but with a new interpretation based on the mnesic imbalance theory, which posits that faulty procedural memory causes deficits in several cognitive skills, resulting in poor performance in theory of mind tasks.

Impaired eye region search accuracy in children with autistic spectrum disorders

To explore mechanisms underlying reduced fixation of eyes in autism, children with Autistic Spectrum Disorders (ASD) and typically developing children were tested in five visual search experiments: simple color feature; color-shape conjunction; face in non-face objects; mouth region; and eye region. No group differences were found for reaction time profile shapes in any of the five experiments, suggesting intact basic search mechanics in children with ASD. Contrary to early reports in the literature, but consistent with other more recent findings, we observed no superiority for conjunction search in children with ASD. Importantly, children with ASD did show reduced accuracy for eye region search (p = .005), suggesting that eyes contribute less to high-level face representations in ASD or that there is an eye region-specific disruption to attentional processes engaged by search in ASD.

Gaze aversion during social style interactions in autism spectrum disorder and Williams syndrome

During face-to-face interactions typically developing individuals use gaze aversion (GA), away from their questioner, when thinking. GA is also used when individuals with autism (ASD) and Williams syndrome (WS) are thinking during question-answer interactions. We investigated GA strategies during face-to-face social style interactions with familiar and unfamiliar interlocutors. Participants with WS and ASD used overall typical amounts/patterns of GA with all participants looking away most while thinking and remembering (in contrast to listening and speaking). However there were a couple of specific disorder related differences: participants with WS looked away less when thinking and interacting with unfamiliar interlocutors; in typical development and WS familiarity was associated with reduced gaze aversion, however no such difference was evident in ASD. Results inform typical/atypical social and cognitive phenotypes. We conclude that gaze aversion serves some common functions in typical and atypical development in terms of managing the cognitive and social load of interactions. There are some specific idiosyncracies associated with managing familiarity in ASD and WS with elevated sociability with unfamiliar others in WS and a lack of differentiation to interlocutor familiarity in ASD. Regardless of the familiarity of the interlocutor, GA is associated with thinking for typically developing as well as atypically developing groups. Social skills training must take this into account.

The effects of birth order and birth interval on the phenotypic expression of autism spectrum disorder

A rise in the prevalence of diagnosed cases of autism spectrum disorder (ASD) has been reported in several studies in recent years. While this rise in ASD prevalence is at least partially related to increased awareness and broadened diagnostic criteria, the role of environmental factors cannot be ruled out, especially considering that the cause of most cases of ASD remains unknown. The study of families with multiple affected children can provide clues about ASD etiology. While the majority of research on ASD multiplex families has focused on identifying genetic anomalies that may underlie the disorder, the study of symptom severity across ASD birth order may provide evidence for environmental factors in ASD. We compared social and cognitive measures of behavior between over 300 first and second affected siblings within multiplex autism families obtained from the Autism Genetic Resource Exchange dataset. Measures included nonverbal IQ assessed with the Ravens Colored Progressive Matrices, verbal IQ assessed with the Peabody Picture Vocabulary Test, and autism severity assessed with the Social Responsiveness Scale (SRS), an instrument established as a quantitative measure of autism. The results indicated that females were more severely impacted by ASD than males, especially first affected siblings. When first and second affected siblings were compared, significant declines in nonverbal and verbal IQ scores were observed. In addition, SRS results demonstrated a significant increase in autism severity between first and second affected siblings consistent with an overall decline in function as indicated by the IQ data. These results remained significant after controlling for the age and sex of the siblings. Surprisingly, the SRS scores were found to only be significant when the age difference between siblings was less than 2 years. These results suggest that some cases of ASD are influenced by a dosage effect involving unknown epigenetic, environmental, and/or immunological factors.

Social phenotypes of autism spectrum disorders and williams syndrome: similarities and differences

Autism spectrum disorders (ASD) and Williams syndrome (WS) both are neurodevelopmental disorders, each with a unique social phenotypic pattern. This review article aims to define the similarities and differences between the social phenotypes of ASD and WS. We review studies that have examined individuals with WS using diagnostic assessments such as the Autism Diagnostic Observation Schedule (ADOS), cross-syndrome direct comparison studies, and studies that have individually examined either disorder. We conclude that (1) individuals with these disorders show quite contrasting phenotypes for face processing (i.e., preference to faces and eyes) and sociability (i.e., interest in and motivation to interact with others), and (2) although the ADOS and a direct comparison study on pragmatic language ability suggest more deficits in ASD, individuals with WS are similarly impaired on social cognition and communicative skills. In light of these results, we discuss how cross-syndrome comparisons between ASD and WS can contribute to developmental theory, cognitive neuroscience, and the development and choice of clinical treatments.

The role of timing in testing nonverbal IQ in children with ASD

15 School-aged high functioning children on the autistic spectrum were compared with a neurotypical cohort on the WISC-III and the KABC-II, to determine the impact of the relatively more strict timing criteria of the former test on the evaluation of nonverbal intelligence. Significant group effects, showing lower performance by the ASD group were found for three of the five sub-tests for the WISC but not for the KABC, peaks and troughs were more evident for the WISC, and the evaluation of intellectual level was also markedly lower for ASD children on the WISC-III as opposed to the KABC-II. The results are discussed in terms of how speed of processing can impact on how children with ASD are 'matched' against neurotypical samples.

"The archeologist's career ended in ruins": hemispheric differences in pun comprehension in autism

Appropriate interpretation of figurative language involves inferring the speaker's intent by integrating word meaning with context. In disorders like autism, understanding intended and contextual meanings in language may pose a challenge. Such difficulties are prevalent even when individuals exhibit otherwise fluent language ability (Szatmari et al., 1990). A pun is a rhetorical technique in which a speaker deliberately invokes multiple meanings through a word or phrase likely resulting in a joke. Comprehending puns may involve identifying multiple meanings of a word, embedding it in right contexts, and understanding the underlying humor. This fMRI study investigated the brain responses associated with figures of speech like puns. In the fMRI scanner, participants read sentences containing puns (e.g. To write with a broken pencil is pointless) and control sentences (literal meaning) presented in a blocked design format. The participants' task was to silently read and understand one meaning (in the literal condition) or two meanings (in the pun condition). Participants with autism, relative to typical controls, showed an increase in overall activation while comprehending sentences containing puns, particularly within the right hemisphere as well as in relatively posterior brain areas. Overall, there was reduced response in left hemisphere areas, reduced response to humor, and more distributed recruitment of regions in autism relative to control participants. We also examined the relationship between symptom severity in autism and verbal ability with brain responses to pun comprehension finding negative and positive correlations respectively. Overall, the results from the present study suggest that individuals with autism resort to altered neural routes in comprehending language in general, and figurative language in particular.

Specificity of dyspraxia in children with autism

OBJECTIVE

To explore the specificity of impaired praxis and postural knowledge to autism by examining three samples of children, including those with autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD), and typically developing (TD) children.

METHOD

Twenty-four children with ASD, 24 children with ADHD, and 24 TD children, ages 8-13, completed measures assessing basic motor control (the Physical and Neurological Exam for Subtle Signs; PANESS), praxis (performance of skilled gestures to command, with imitation, and tool use) and the ability to recognize correct hand postures necessary to perform skilled gestures (the Postural Knowledge Test; PKT).

RESULTS

Children with ASD performed significantly worse than TD children on all three assessments. In contrast, children with ADHD performed significantly worse than TD controls on PANESS but not on the praxis examination or PKT. Furthermore, children with ASD performed significantly worse than children with ADHD on both the praxis examination and PKT, but not on the PANESS.

CONCLUSIONS

Whereas both children with ADHD and children with ASD show impairments in basic motor control, impairments in performance and recognition of skilled motor gestures, consistent with dyspraxia, appear to be specific to autism. The findings suggest that impaired formation of perceptual-motor action models necessary to development of skilled gestures and other goal directed behavior is specific to autism; whereas, impaired basic motor control may be a more generalized finding.

Motor learning relies on integrated sensory inputs in ADHD, but over-selectively on proprioception in autism spectrum conditions

The brain builds an association between action and sensory feedback to predict the sensory consequence of self-generated motor commands. This internal model of action is central to our ability to adapt movements and may also play a role in our ability to learn from observing others. Recently, we reported that the spatial generalization patterns that accompany adaptation of reaching movements were distinct in children with autism spectrum disorder (ASD) as compared with typically developing (TD) children. To test whether the generalization patterns are specific to ASD, here, we compared the patterns of adaptation with those in children with attention deficit hyperactivity disorder (ADHD). Consistent with our previous observations, we found that in ASD, the motor memory showed greater than normal generalization in proprioceptive coordinates compared with both TD children and children with ADHD; children with ASD also showed slower rates of adaptation compared with both control groups. Children with ADHD did not show this excessive generalization to the proprioceptive target, but they did show excessive variability in the speed of movements with an increase in the exponential distribution of responses (τ) as compared with both TD children and children with ASD. The results suggest that slower rate of adaptation and anomalous bias towards proprioceptive feedback during motor learning are characteristics of autism, whereas increased variability in execution is a characteristic of ADHD.

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.

Who's Missing the Point? A Commentary on Claims that Autistic Persons Have a Specific Deficit in Figurative Language Comprehension

It's become a caricature of autistic persons that they don't understand figurative language. Despite empirical evidence to the contrary, three of the four contributions to this special issue endorse this stereotype without question. And all four contributions attribute this supposed deficit to even shakier fallacies, such as the controversial claim that autistic people lack empathy or a 'theory of mind.' In this commentary, we begin by reviewing the literature more exhaustively than the other contributions, and we highlight a point that they missed: Autistic persons are likely to have difficulty comprehending figurative language if they also have difficulty comprehending language in general. There doesn't seem to be a specific deficit in figurative language unique to autism. We also tackle the claim that autistic people lack empathy. And we question the existence of a 'theory of mind area,' while demonstrating the pitfalls that ensnarl researchers when they strain to interpret differences between autistic and non-autistic brain activity as solely autistic deficits.

Beyond matching on the mean in developmental disabilities research

The matching of groups is a traditional way to control for confounding variables in developmental disabilities research. The equivalency of means across groups is routinely checked for these variables, but not the homogeneity of their variances or the shapes of their distributions. In the present paper, it is argued that group matching can go seriously wrong unless it directly confronts the distributional concerns by the use of well-known statistical indices and very simple graphical displays of the distributions. The question of the equivalency of item response profiles is also addressed since two participants or two groups of participants can obtain the same overall score on the matching variable by passing different items. In this case, the matching cannot be considered satisfactory because of poor concordance between the molar (overall score) and molecular (item scores) levels of matching. Angoff's Delta plot method, a statistical approach for detecting differential item functioning across small groups is described. It is promising as a simple way to prove whole test/individual item correspondence and, in addition, a useful tool for making post hoc statistical analyses at the item level on the dependent variables.

The extent of working memory deficits associated with Williams syndrome: exploration of verbal and spatial domains and executively controlled processes

The present study investigated verbal and spatial working memory (WM) functioning in individuals with the neuro-developmental disorder Williams syndrome (WS) using WM component tasks. While there is strong evidence of WM impairments in WS, previous research has focused on short-term memory and has neglected assessment of executive components of WM. There is a particular lack of consensus concerning the profile of verbal WM functioning in WS. Here, WS participants were compared to typically developing participants matched for (1) verbal ability and (2) spatial ability (N=14 in each of the 3 groups). Individuals with WS were impaired on verbal WM tasks, both those involving short-term maintenance of information and executive manipulation, in comparison to verbal-matched controls. Surprisingly, individuals with WS were not impaired on a spatial task assessing short-term maintenance of information in memory (remembering spatial locations) compared to spatial-matched controls. They were, however, impaired on a spatial executive WM task requiring the manipulation of spatial information in memory. The present study suggests that individuals with WS show WM impairments that extend to both verbal and spatial domains, although spatial deficits are selective to executive aspects of WM function.

A comparison of the trait emotional intelligence profiles of individuals with and without Asperger syndrome

The extent to which the socioemotional impairments of Asperger syndrome (AS) might be extreme manifestations of individual differences within the general population remains under-explored. We compared the trait emotional intelligence (trait EI) profiles of 30 individuals with AS against the profiles of 43 group-matched controls using the Trait Emotional Intelligence Questionnaire (TEIQue). Participants with AS scored significantly lower than controls on 12 of the 15 TEIQue facets (ηp2 = 0.09 to 0.49) as well as on all four factors and the global score of the construct (ηp2 = 0.07 to 0.41). There was a significant main effect of gender, with men generally scoring higher than women. Results are discussed from the perspective of trait EI theory, with emphasis on its implications for the socioemotional impairments associated with AS.

A comparison of the development of audiovisual integration in children with autism spectrum disorders and typically developing children

This study aimed to investigate the development of audiovisual integration in children with Autism Spectrum Disorder (ASD). Audiovisual integration was measured using the McGurk effect in children with ASD aged 7-16 years and typically developing children (control group) matched approximately for age, sex, nonverbal ability and verbal ability. Results showed that the children with ASD were delayed in visual accuracy and audiovisual integration compared to the control group. However, in the audiovisual integration measure, children with ASD appeared to 'catch-up' with their typically developing peers at the older age ranges. The suggestion that children with ASD show a deficit in audiovisual integration which diminishes with age has clinical implications for those assessing and treating these children.

Perceptual reasoning predicts handwriting impairments in adolescents with autism

BACKGROUND

We have previously shown that children with autism spectrum disorder (ASD) have specific handwriting deficits consisting of poor form, and that these deficits are predicted by their motor abilities. It is not known whether the same handwriting impairments persist into adolescence and whether they remain linked to motor deficits.

METHODS

A case-control study of handwriting samples from adolescents with and without ASD was performed using the Minnesota Handwriting Assessment. Samples were scored on an individual letter basis in 5 categories: legibility, form, alignment, size, and spacing. Subjects were also administered an intelligence test and the Physical and Neurological Examination for Subtle (Motor) Signs (PANESS).

RESULTS

We found that adolescents with ASD, like children, show overall worse performance on a handwriting task than do age- and intelligence-matched controls. Also comparable to children, adolescents with ASD showed motor impairments relative to controls. However, adolescents with ASD differ from children in that Perceptual Reasoning Indices were significantly predictive of handwriting performance whereas measures of motor skills were not.

CONCLUSIONS

Like children with ASD, adolescents with ASD have poor handwriting quality relative to controls. Despite still demonstrating motor impairments, in adolescents perceptual reasoning is the main predictor of handwriting performance, perhaps reflecting subjects' varied abilities to learn strategies to compensate for their motor impairments.

Sound before meaning: word learning in autistic disorders

Successful word learning depends on the integration of phonological and semantic information with social cues provided by interlocutors. How then, do children with autism spectrum disorders (ASDs) learn new words when social impairments pervade? We recorded the eye-movements of verbally-able children with ASD and their typical peers while completing a word learning task in a social context. We assessed learning of semantic and phonological features immediately after learning and again four weeks later. Eye-movement data revealed that both groups could follow social cues, but that typically developing children were more sensitive to the social informativeness of gaze cues. In contrast, children with ASD were more successful than peers at mapping phonological forms to novel referents; however, this advantage was not maintained over time. Typical children showed clear consolidation of learning both semantic and phonological information, children with ASD did not. These results provide unique evidence of qualitative differences in word learning and consolidation and elucidate the different mechanisms underlying the unusual nature of autistic language.

Attention-deficit/hyperactivity disorder and Williams syndrome: shared behavioral and neuropsychological profiles

We compared verbally matched attention-deficit/hyperactivity disorder (ADHD), Williams syndrome (WS), and typically developing individuals (N = 19 each group) on behavioral symptoms (Conners ADHD rating scale) and neuropsychological functioning. Neuropsychological tasks included those that assessed short-term memory and executive functions from the CANTAB (Cambridge Neuropsychological Test Automated Battery) neuropsychological battery. Children with WS scored within the abnormal range and did not differ in severity from ADHD children on the Conners Oppositionality, Cognitive Problems/Inattention, Hyperactivity, and ADHD Index subscales. The WS and ADHD groups also showed similar patterns of neuropsychological functioning, particularly in working memory (WM) strategy use and delayed short-term memory (STM). The findings may have clinical implications for the management of individuals with WS, highlighting the potential significance of behavioral, educational, and pharmacological strategies and treatments known to be useful in the treatment of children with ADHD for individuals with WS.

Basal ganglia shapes predict social, communication, and motor dysfunctions in boys with autism spectrum disorder

OBJECTIVE

Basal ganglia abnormalities have been suggested as contributing to motor, social, and communicative impairments in autism spectrum disorder (ASD). Volumetric analyses offer limited ability to detect localized differences in basal ganglia structure. Our objective was to investigate basal ganglia shape abnormalities and their association with behavioral features of ASD, which may involve multiple frontal-subcortical circuits.

METHOD

Basal ganglia were manually delineated from MR images of 32 boys with ASD and 45 typically developing (TD) boys. Large deformation diffeomorphic metric mapping (LDDMM) was used to assess between-group differences in basal ganglia shape and to examine associations with motor, praxis, and reciprocal social and communicative impairments in ASD.

RESULTS

Boys with ASD showed changes in right basal ganglia shape as compared with TD boys; surface deformation was present in the caudate, putamen, and globus pallidus but did not stand up to correction for multiple comparisons. Brain-behavior correlation findings were more robust; analyses accounting for multiple comparisons revealed, in boys with ASD, surface inward deformation of the right posterior putamen predicted poorer motor skill, whereas surface inward deformation of the bilateral anterior and posterior putamen predicted poorer praxis. Surface outward deformation in the bilateral medial caudate head predicted greater reciprocal social and communicative impairment.

CONCLUSIONS

Motor, social, and communicative impairments in boys with ASD are associated with shape abnormalities in the basal ganglia. The findings suggest abnormalities within parallel frontal-subcortical circuits are differentially associated with impaired acquisition of motor and reciprocal social and communicative skills in ASD.

Children with autism show specific handwriting impairments

BACKGROUND

Handwriting skills, which are crucial for success in school, communication, and building children's self-esteem, have been observed to be poor in individuals with autism. Little information exists on the handwriting of children with autism, without delineation of specific features that can contribute to impairments. As a result, the specific aspects of handwriting in which individuals with autism demonstrate difficulty remain unknown.

METHODS

A case-control study of handwriting samples from children with and without autism spectrum disorders (ASD) was performed using the Minnesota Handwriting Assessment. Samples were scored on an individual letter basis in 5 categories: legibility, form, alignment, size, and spacing. Subjects were also tested on the Wechsler Intelligence Scale for Children-IV and the Physical and Neurological Examination for Subtle (Motor) Signs.

RESULTS

We found that children with ASD do indeed show overall worse performance on a handwriting task than do age- and intelligence-matched controls. More specifically, children with ASD show worse quality of forming letters but do not show differences in their ability to correctly size, align, and space their letters. Within the ASD group, motor skills were significantly predictive of handwriting performance, whereas age, gender, IQ, and visuospatial abilities were not.

CONCLUSIONS

We addressed how different elements of handwriting contribute to impairments observed in children with autism. Our results suggest that training targeting letter formation, in combination with general training of fine motor control, may be the best direction for improving handwriting performance in children with autism.

Associations of postural knowledge and basic motor skill with dyspraxia in autism: implication for abnormalities in distributed connectivity and motor learning

Children with autism often have difficulty performing skilled movements. Praxis performance requires basic motor skill, knowledge of representations of the movement (mediated by parietal regions), and transcoding of these representations into movement plans (mediated by premotor circuits). The goals of this study were (a) to determine whether dyspraxia in autism is associated with impaired representational ("postural") knowledge and (b) to examine the contributions of postural knowledge and basic motor skill to dyspraxia in autism. Thirty-seven children with autism spectrum disorder (ASD) and 50 typically developing (TD) children, ages 8-13, completed (a) an examination of basic motor skills, (b) a postural knowledge test assessing praxis discrimination, and (c) a praxis examination. Children with ASD showed worse basic motor skill and postural knowledge than did controls. The ASD group continued to show significantly poorer praxis than did controls after accounting for age, IQ, basic motor skill, and postural knowledge. Dyspraxia in autism appears to be associated with impaired formation of spatial representations, as well as transcoding and execution. Distributed abnormality across parietal, premotor, and motor circuitry, as well as anomalous connectivity, may be implicated.

Eye-movement patterns are associated with communicative competence in autistic spectrum disorders

BACKGROUND

Investigations using eye-tracking have reported reduced fixations to salient social cues such as eyes when participants with autism spectrum disorders (ASD) view social scenes. However, these studies have not distinguished different cognitive phenotypes.

METHODS

The eye-movements of 28 teenagers with ASD and 18 typically developing peers were recorded as they watched videos of peers interacting in familiar situations. Within ASD, we contrasted the viewing patterns of those with and without language impairments. The proportion of time spent viewing eyes, mouths and other scene details was calculated, as was latency of first fixation to eyes. Finally, the association between viewing patterns and social-communicative competence was measured.

RESULTS

Individuals with ASD and age-appropriate language abilities spent significantly less time viewing eyes and were slower to fixate the eyes than typically developing peers. In contrast, there were no differences in viewing patterns between those with language impairments and typically developing peers. Eye-movement patterns were not associated with social outcomes for either language phenotype. However, increased fixations to the mouth were associated with greater communicative competence across the autistic spectrum.

CONCLUSIONS

Attention to both eyes and mouths is important for language development and communicative competence. Differences in fixation time to eyes may not be sufficient to disrupt social competence in daily interactions. A multiple cognitive deficit model of ASD, incorporating different language phenotypes, is advocated.

Block design reconstruction skills: not a good candidate for an endophenotypic marker in autism research

Superior performance on block design tasks is reported in autistic individuals, although it is not consistently found in high-functioning individuals or individuals with Asperger Syndrome. It is assumed to reflect weak central coherence: an underlying cognitive deficit, which might also be part of the genetic makeup of the disorder. We assessed block design reconstruction skills in high-functioning individuals with autism spectrum disorders (ASD) from multi-incidence families and in their parents. Performance was compared to relevant matched control groups. We used a task that was assumed to be highly sensitive to subtle performance differences. We did not find individuals with ASD to be significantly faster on this task than the matched control group, not even when the difference between reconstruction time of segmented and pre-segmented designs was compared. However, we found individuals with ASD to make fewer errors during the process of reconstruction which might indicate some dexterity in mental segmentation. However, parents of individuals with ASD did not perform better on the task than control parents. Therefore, based on our data, we conclude that mental segmentation ability as measured with a block design reconstruction task is not a neurocognitive marker or endophenotype useful in genetic studies.

The eyes or the mouth? Feature salience and unfamiliar face processing in Williams syndrome and autism

Using traditional face perception paradigms the current study explores unfamiliar face processing in two neurodevelopmental disorders. Previous research indicates that autism and Williams syndrome (WS) are both associated with atypical face processing strategies. The current research involves these groups in an exploration of feature salience for processing the eye and mouth regions of unfamiliar faces. The tasks specifically probe unfamiliar face matching by using (a) upper or lower face features, (b) the Thatcher illusion, and (c) featural and configural face modifications to the eye and mouth regions. Across tasks, individuals with WS mirror the typical pattern of performance, with greater accuracy for matching faces using the upper than using the lower features, susceptibility to the Thatcher illusion, and greater detection of eye than mouth modifications. Participants with autism show a generalized performance decrement alongside atypicalities, deficits for utilizing the eye region, and configural face cues to match unfamiliar faces. The results are discussed in terms of feature salience, structural encoding, and the phenotypes typically associated with these neurodevelopmental disorders.

Brief report: The level and nature of autistic intelligence revisited

Owing to higher performance on the Raven's Progressive Matrices (RPM) than on the Wechsler Intelligence Scales (WIS), it has recently been argued that intelligence is underestimated in autism. This study examined RPM and WIS IQs in 48 individuals with autism, a mixed clinical (n = 28) and a neurotypical (n = 25) control group. Average RPM IQ was higher than WIS IQ only in the autism group, albeit to a much lesser degree than previously reported and only for individuals with WIS IQs <85. Consequently, and given the importance of reliable multidimensional IQ estimates in autism, the WIS are recommended as first choice IQ measure in high functioning individuals. Additional testing with the RPM might be required in the lower end of the spectrum.

Evidence that the pattern of visuomotor sequence learning is altered in children with autism

Motor deficits are commonly reported in autism, with one of the most consistent findings being impaired execution of skilled movements and gestures. Given the developmental nature of autism, it is possible that deficits in motor/procedural learning contribute to impaired acquisition of motor skills. Thus, careful examination of mechanisms underlying learning and memory may be critical to understanding the neural basis of autism. A previous study reported impaired motor learning in children with high-functioning autism (HFA); however, it is unclear whether the observed deficits in motor learning are due, in part, to impaired motor execution and whether these deficits are specific to autism. In order to examine these questions, 153 children (52 with HFA, 39 with attention-deficit/hyperactivity disorder (ADHD) and 62 typically developing (TD) children) participated in two independent experiments using a Rotary Pursuit task, with change in performance across blocks as a measure of learning. For both tasks, children with HFA demonstrated significantly less change in performance than did TD children, even when differences in motor execution were minimized. Differences in learning were not seen between ADHD and TD groups on either experiment. Analyses of the pattern of findings revealed that compared with both ADHD and TD children, children with HFA showed a similar degree of improvement in performance; however, they showed significantly less decrement in performance when presented with an alternate ("interference") pattern. The findings suggest that mechanisms underlying acquisition of novel movement patterns may differ in children with autism. These findings may help explain impaired skill development in children with autism and help to guide approaches for helping children learn novel motor, social and communicative skills.

Acquisition of internal models of motor tasks in children with autism

Children with autism exhibit a host of motor disorders including poor coordination, poor tool use and delayed learning of complex motor skills like riding a tricycle. Theory suggests that one of the crucial steps in motor learning is the ability to form internal models: to predict the sensory consequences of motor commands and learn from errors to improve performance on the next attempt. The cerebellum appears to be an important site for acquisition of internal models, and indeed the development of the cerebellum is abnormal in autism. Here, we examined autistic children on a range of tasks that required a change in the motor output in response to a change in the environment. We first considered a prism adaptation task in which the visual map of the environment was shifted. The children were asked to throw balls to visual targets with and without the prism goggles. We next considered a reaching task that required moving the handle of a novel tool (a robotic arm). The tool either imposed forces on the hand or displaced the cursor associated with the handle position. In all tasks, the children with autism adapted their motor output by forming a predictive internal model, as exhibited through after-effects. Surprisingly, the rates of acquisition and washout were indistinguishable from normally developing children. Therefore, the mechanisms of acquisition and adaptation of internal models in self-generated movements appeared normal in autism. Sparing of adaptation suggests that alternative mechanisms contribute to impaired motor skill development in autism. Furthermore, the findings may have therapeutic implications, highlighting a reliable mechanism by which children with autism can most effectively alter their behaviour.

Superior fluid intelligence in children with Asperger's disorder

Asperger's disorder is one of autistic spectrum disorders; sharing clinical features with autism, but without developmental delay in language acquisition. There have been some studies of intellectual functioning in autism so far, but very few in Asperger's disorder. In the present study, we investigated abstract reasoning ability, whose form of intelligence has been labeled fluid intelligence in the theory of Cattell [Cattell, R. B. (1963). Theory of fluid and crystallized intelligence: A critical experiment. Journal of Educational Psychology, 54, 1-22.], in children with Asperger's disorder. A test of fluid intelligence, the Raven's Standard Progressive Matrices Test, was administered to 17 children with Asperger's disorder and 17 age-, gender-, and FIQ-matched normal children. The results showed that children with Asperger's disorder outperformed on the test of fluid reasoning than typically developing children. We suggest that individuals with Asperger's disorder have higher fluid reasoning ability than normal individuals, highlighting superior fluid intelligence.

The level and nature of autistic intelligence

Autistics are presumed to be characterized by cognitive impairment, and their cognitive strengths (e.g., in Block Design performance) are frequently interpreted as low-level by-products of high-level deficits, not as direct manifestations of intelligence. Recent attempts to identify the neuroanatomical and neurofunctional signature of autism have been positioned on this universal, but untested, assumption. We therefore assessed a broad sample of 38 autistic children on the preeminent test of fluid intelligence, Raven's Progressive Matrices. Their scores were, on average, 30 percentile points, and in some cases more than 70 percentile points, higher than their scores on the Wechsler scales of intelligence. Typically developing control children showed no such discrepancy, and a similar contrast was observed when a sample of autistic adults was compared with a sample of nonautistic adults. We conclude that intelligence has been underestimated in autistics.

Level of functioning in autism spectrum disorders: phenotypic congruence among affected siblings

Little evidence supports that siblings with autism exhibit the same behaviors; however, some findings suggest that level of functioning shows familial aggregation. We tested this notion among multiplex families participating with the Autism Genetic Resource Exchange (AGRE) Consortium, using scores on the Peabody Picture Vocabulary Test-Third Edition (N = 204 families), the Ravens Colored Progressive Matrices (N = 226 families), and the Vineland Adaptive Behavior Scales (N = 348 families). Intraclass Correlation Coefficients revealed that siblings with autism/autism spectrum disorders (ASD) were more similar on measures of verbal and nonverbal IQ and adaptive functioning than were unrelated children with autism/ASD. Preliminary twin correlations indicated strong genetic effects for some skill domains and the influence of shared environmental factors for others.

Emotion perception in Asperger's syndrome and high-functioning autism: the importance of diagnostic criteria and cue intensity

This study compared emotion perception accuracy between children with Asperger's syndrome (AS) and high-functioning autism (HFA). Thirty children were diagnosed with AS or HFA based on empirically supported diagnostic criteria and administered an emotion perception test consisting of facial expressions and tone of voice cues that varied in intensity. Participants with AS and the typically developing standardization sample of the emotion perception instrument had the same mean emotion perception accuracy, whereas participants with HFA performed significantly worse. Results also provided preliminary evidence for a difference in accuracy perceiving low-intensity tone of voice cues between participants with HFA and AS. Future research to build on these initial findings should include attention to tone of voice, underlying processing, and cue intensity.

Beyond pragmatics: morphosyntactic development in autism

Language acquisition research in autism has traditionally focused on high-level pragmatic deficits. Few studies have examined grammatical abilities in autism, with mixed findings. The present study addresses this gap in the literature by providing a detailed investigation of syntactic and higher-level discourse abilities in verbal children with autism, age 5 years. Findings indicate clear language difficulties that go beyond what would be expected based on developmental level; specifically, syntactic delays, impairments in discourse management and increased production of non-meaningful words (jargon). The present study indicates a highly specific pattern of language impairments, and importantly, syntactic delays, in a group of children with autism carefully matched on lexical level and non-verbal mental age with children with developmental delays and typical development.

Is the Linguistic Content of Speech Less Salient than its Perceptual Features in Autism?

Open-ended tasks are rarely used to investigate cognition in autism. No known studies have directly examined whether increased attention to the perceptual level of speech in autism might contribute to a reduced tendency to process language meaningfully. The present study investigated linguistic versus perceptual speech processing preferences. Children with autism and controls were tested on a quasi-open-format paradigm, in which speech stimuli contained competing linguistic and perceptual information, and could be processed at either level. Relative to controls, children with autism exhibited superior perceptual processing of speech. However, whilst their tendency to preferentially process linguistic rather than perceptual information was weaker than that of controls, it was nevertheless their primary processing mode. Implications for language acquisition in autism are discussed.

Lateral glances toward moving stimuli among young children with autism: Early regulation of locally oriented perception?

Autistic adults display enhanced and locally oriented low-level perception of static visual information, but diminished perception of some types of movement. The identification of potential precursors, such as atypical perceptual processing, among very young children would be an initial step toward understanding the development of these phenomena. The purpose of this study was to provide an initial measure and interpretation of atypical visual exploratory behaviors toward inanimate objects (AVEBIOs) among young children with autism. A coding system for AVEBIOs was constructed from a corpus of 40 semistandardized assessments of autistic children. The most frequent atypical visual behavior among 15 children aged 33-73 months was lateral glance that was mostly oriented toward moving stimuli and was detected reliably by the experimenters (intraclass correlation > .90). This behavior was more common among autistic than typically developing children of similar verbal mental age and chronological age. As lateral vision is associated with the filtering of high spatial frequency (detail perception) information and the facilitation of high temporal frequencies (movement perception), its high prevalence among very young autistic children may reflect early attempts to regulate and/or optimize both excessive amounts of local information and diminished perception of movement. These findings are initial evidence for the need to consider the neural bases and development of atypical behaviors and their implications for intervention strategies.

Association of Per1 and Npas2 with autistic disorder: support for the clock genes/social timing hypothesis

Clock gene anomalies have been suggested as causative factors in autism. We screened eleven clock/clock-related genes in a predominantly high-functioning Autism Genetic Resource Exchange sample of strictly diagnosed autistic disorder progeny and their parents (110 trios) for association of clock gene variants with autistic disorder. We found significant association (P<0.05) for two single-nucleotide polymorphisms in per1 and two in npas2. Analysis of all possible combinations of two-marker haplotypes for each gene showed that in npas2 40 out of the 136 possible two-marker combinations were significant at the P<0.05 level, with the best result between markers rs1811399 and rs2117714, P=0.001. Haplotype analysis within per1 gave a single significant result: a global P=0.027 for the markers rs2253820-rs885747. No two-marker haplotype was significant in any of the other genes, despite the large number of tests performed. Our findings support the hypothesis that these epistatic clock genes may be involved in the etiology of autistic disorder. Problems in sleep, memory and timing are all characteristics of autistic disorder and aspects of sleep, memory and timing are each clock-gene-regulated in other species. We identify how our findings may be relevant to theories of autism that focus on the amygdala, cerebellum, memory and temporal deficits. We outline possible implications of these findings for developmental models of autism involving temporal synchrony/social timing.

Genome-wide expression profiling of lymphoblastoid cell lines distinguishes different forms of autism and reveals shared pathways

Autism is a heterogeneous condition that is likely to result from the combined effects of multiple genetic factors interacting with environmental factors. Given its complexity, the study of autism associated with Mendelian single gene disorders or known chromosomal etiologies provides an important perspective. We used microarray analysis to compare the mRNA expression profile in lymphoblastoid cells from males with autism due to a fragile X mutation (FMR1-FM), or a 15q11-q13 duplication (dup(15q)), and non-autistic controls. Gene expression profiles clearly distinguished autism from controls and separated individuals with autism based on their genetic etiology. We identified 68 genes that were dysregulated in common between autism with FMR1-FM and dup(15q). We also identified a potential molecular link between FMR1-FM and dup(15q), the cytoplasmic FMR1 interacting protein 1 (CYFIP1), which was up-regulated in dup(15q) patients. We were able to confirm this link in vitro by showing common regulation of two other dysregulated genes, JAKMIP1 and GPR155, downstream of FMR1 or CYFIP1. We also confirmed the reduction of the Jakmip1 protein in Fmr1 knock-out mice, demonstrating in vivo relevance. Finally, we showed independent confirmation of roles for JAKMIP1 and GPR155 in autism spectrum disorders (ASDs) by showing their differential expression in male sib pairs discordant for idiopathic ASD. These results provide evidence that blood derived lymphoblastoid cells gene expression is likely to be useful for identifying etiological subsets of autism and exploring its pathophysiology.

Brief report: data on the Stanford-Binet Intelligence Scales (5th ed.) in children with autism spectrum disorder

The Fifth Edition of the Stanford-Binet Intelligence Scales (SB5; Roid, G. H. (2003). Stanford Binet intelligence scales (5th ed.). Itasca, IL: Riverside Publishing) is relatively new, with minimal published research on general populations and none with special populations. The present study provides information on the cognitive profiles of children with ASD (N=63) and on the whether the abbreviated battery is representative of the full scale. A high percentage of the children had significantly stronger nonverbal (vs. verbal) skills. This pattern was not related to Full Scale IQ, age or diagnostic subgroup. IQs derived from the abbreviated battery accounted for a large proportion of the variance in FSIQ relative to comparable abbreviated batteries. However, caution is warranted when using the abbreviated battery, as it misrepresents actual ability in a small percentage of cases.