A clinical and neurobehavioural review of high-functioning autism and Asperger's disorder

[Motor impairments in children with autism spectrum disorders: causes and possibilities for correction]

Autism spectrum disorder (ASD) is characterized by triad of abnormalities in the form of developmental distortion with a lack of communicative abilities, behavioral and motor stereotypies. Etiology and pathogenesis of disease currently are unknown, but multifactorial causes of this pathology have been suggested. Although social disorders are considered a defining characteristic, motor disorders are a key feature of ASD. They are based on a postural control impairment, which is accompanied by delayed psychomotor development, reduced ability to motor synchronism in early childhood, modified arrangement of muscles, problems with balance and gait, postural instability, coordination deficiency, presence of motor dyspraxia and other abnormalities.

OBJECTIVE

To analyze current scientific data about motor disorders in ASD and their correction possibilities in children with this pathology.

MATERIAL AND METHODS

Analysis of publications, contained in PubMed and Google Scholar databases, which give consideration to motor disorders in children with ASD, was carried out. The search was done by keywords: motor disorders, children, autism spectrum disorder, causes, correction.

RESULTS AND CONCLUSION

Adaptive physical culture during individual training is one of the available and effective methods of physical rehabilitation in patients with ASD. Children with ASD need three levels of psychological support, each of which offers individual exercises, depending on the nature and severity of speech and cognitive impairment.

Synthesis of genetic association studies on autism spectrum disorders using a genetic model-free approach

BACKGROUND

Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of neurodevelopmental disorders. Despite the extensive efforts of scientists, the etiology of ASD is far from completely elucidated. In an effort to enlighten the genetic architecture of ASDs, a meta-analysis of all available genetic association studies (GAS) was conducted.

METHODS

We searched in the Human Genome Epidemiology Navigator (HuGE Navigator) and PubMed for available case-control GAS of ASDs. The threshold for meta-analysis was two studies per genetic variant. The association between genotype distribution and ASDs was examined using the generalized linear odds ratio (ORG). For variants with available allele frequencies, the examined model was the allele contrast.

RESULTS

Overall, 57 candidate genes and 128 polymorphisms were investigated in 159 articles. In total 28 genetic polymorphisms have been shown to be associated with ASDs, that are harbored in 19 genes. Statistically significant results were revealed for the variants of the following genes adenosine deaminase (ADA), bone marrow stromal cell antigen-1 (CD157/BST1), Dopamine receptor D1 (DRD1), engrailed homolog 2 (EN2), met proto-oncogene (MET), methylenetetrahydrofolate reductase (MTHFR), solute carrier family 6 member 4 (SLC6A4), Synaptosomal-associated protein, 25kDa (SNAP-25) and vitamin D receptor (VDR). In the allele contrast model of cases versus healthy controls, significant associations were observed for Adrenoceptor Alpha 1B (ADRA1B), acetyl serotonin O - methyltransferase (ASMT), complement component 4B (C4B), dopamine receptor D3 (DRD3), met proto-oncogene (MET), neuroligin 4, X-linked (NLGN4), neurexin 1 (NRXN1), oxytocin receptor (OXTR), Serine/Threonine-Protein Kinase PFTAIRE-1 (PFTK1), Reelin (RELN) and Ras-like without CAAX 2 (RIT2).

CONCLUSION

These significant findings provide further evidence for genetic factors' implication in ASDs offering new perspectives in means of prevention and prognosis.

Translation, Cross-Cultural Adaptation, and Validation of a Dutch Version of the Actions and Feelings Questionnaire in Autistic and Neurotypical Adults

The actions and feelings questionnaire (AFQ) provides a short, self-report measure of how well someone uses and understands visual communicative signals such as gestures. The objective of this study was to translate and cross-culturally adapt the AFQ into Dutch (AFQ-NL) and validate this new version in neurotypical and autistic populations. Translation and adaptation of the AFQ consisted of forward translation, synthesis, back translation, and expert review. In order to validate the AFQ-NL, we assessed convergent and divergent validity. We additionally assessed internal consistency using Cronbach’s alpha. Validation and reliability outcomes were all satisfactory. The AFQ-NL is a valid adaptation that can be used for both autistic and neurotypical populations in the Netherlands.

Factors associated with positive mental health in young adults with a neurodevelopmental disorder

BACKGROUND

Positive dimension of mental health has gained less attention in previous research on individuals with neurodevelopmenal disorders. However, knowledge on factors associated with mental well-being is crucial for planning effective interventions for this target group.

AIMS

The aim of the study was to investigate the determinants of positive mental health among young adults with neurodevelopmental disorders.

METHODS AND PROCEDURES

The study sample consisted of 171 young adults (18-35 years, mean age 25 years, SD 4.35) with a diagnosis of Autism Spectrum Disorder (ASD) or ADHD/ADD. The data were collected with questionnaires.

RESULTS

The mean score of SWEMWBS was 20.98 (n = 168, ranging 14.75-35.00, SD = 3.55). Provisions of social relationships, functional capacity and self-rated state of health associated independently with positive mental health.

CONCLUSION AND IMPLICATIONS

The level of positive mental health of study participants was relatively low compared with previous studies in other clinical settings or general populations. Promotion of social competence and social relationship should be included in rehabilitation programmes targeted at individuals with neurodevelopmental disorder. This may be beneficial in reaching also other goals set for the rehabilitation, such as increasing capacity to work or study.

Toe Walking Assessment in Autism Spectrum Disorder Subjects: A Systematic Review

There is increasing evidence that autism spectrum disorder (ASD) subjects have also motor impairments. Toe walking (TW) is a phenomenon that can be found in ASD subjects during gait, even if this condition was found not to be necessarily related only to walking, since these children often also stand and run on their tiptoes. Since persistent TW in ASD subjects may contribute to secondary shortening of the Achilles's tendon, it becomes important to have an assessment tool and/or outcome measure for both the clinical and rehabilitative settings. The aim of this systematic review is to critically evaluate and describe the methods employed to assess toe walking in ASD subjects. The systematic review protocol was previously registered on PROSPERO. We conducted an extensive literature search in PubMed, CINAHL, PsycINFO, The Cochrane Library, and Scopus databases. There were no restrictions on the types of study design eligible for inclusion. Ten studies were included in the systematic review. Risk of bias of the included studies was conducted using the following instruments depending on the study types: STROBE Statement, Cochrane risk of bias tool, and CARE checklist. Almost all the included studies (8/10) proposed a tip-toe behavior (TTB) assessment only during walking. Nine out of ten of the included studies assessed TTB using a qualitative methodology. The results evidenced the heterogeneity of qualitative methods and a lack of a structured quantitative test to assess toe walking in ASD subjects. Autism Res 2018, 11: 1404-1415. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY ABSTRACT: Toe walking (TW) is a phenomenon that can be found during ASD subject's gait. The persistence of this behavior may contribute to secondary Achilles's tendon shortening. In this perspective it becomes important to have an assessment tool and/or outcome measure for both the clinical and rehabilitative settings. The current systematic review aimed to describe the methods employed to assess TW. The results evidenced the lack and the need of a structured quantitative test to assess TW in ASD subjects.

Increased Left Inferior Temporal Gyrus Was Found in Both Low Function Autism and High Function Autism

Previous neuroimaging studies of autism spectrum disorder (ASD) have focused on subjects with IQ > 70 or ASD without considering IQ levels. It remains unclear whether differences in brain anatomy in this population are associated with variations in clinical phenotype. In this study, 19 children with low functioning autism (LFA) and 19 children with high functioning autism (HFA) were compared with 27 healthy controls (HC). We found increased gray matter volume (GMV) in the left inferior temporal gyrus in subjects with both HFA and LFA and increased GMV of left middle temporal gyrus BA21 was found only in the LFA group. A significant negative correlation was found between the left inferior temporal gyrus (LITG) and the score of repetitive behavior in the HFA group.

Depletion of Stercobilin in Fecal Matter from a Mouse Model of Autism Spectrum Disorders

INTRODUCTION

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders lacking a clinical biomarker for diagnosis. Emerging evidence shows that intestinal microflora from ASD subjects can be distinguished from controls, suggesting metabolite differences due to the action of intestinal microbes may provide a means for identifying potential biomarkers for ASD.

OBJECTIVES

The aim of this study was to determine if quantitative differences in levels of stercobilin and stercobilinogen, metabolites produced by biological action of intestinal microflora, exist in the fecal matter between an ASD mouse model population and controls.

METHODS

Pairs of fecal samples were collected from two mouse groups, an ASD model group with Timothy syndrome 2 (TS2-NEO) and a gender-matched control group. After centrifugation, supernatant was spiked with an ¹⁸O-labeled stercobilin isotopomer and subjected to solid phase extraction for processing. Extracted samples were spotted on a stainless steel plate and subjected to matrix-assisted laser desorption and ionization mass spectrometry using dihydroxybenzoic acid as the matrix (n = 5). Peak areas for bilins and ¹⁸O-stercobilin isotopomers were determined in each fecal sample.

RESULTS

A 40-45% depletion in stercobilin in TS2-NEO fecal samples compared with controls was observed with p < 0.05; a less dramatic depletion was observed for stercobilinogen.

CONCLUSIONS

The results show that stercobilin depletion in feces is observed for an ASD mouse model vs. controls. This may help to explain recent observations of a less diverse microbiome in humans with ASD and may prove helpful in developing a clinical ASD biomarker.

Age-related differences in inhibitory control and memory updating in boys with Asperger syndrome

Deficits in specific executive domains are highly prevalent in autism spectrum disorder; however, age-related improvements in executive functions (reflecting prefrontal maturational changes) have been reported even in individuals diagnosed with autism. The current study examined two components of cognitive flexibility (inhibition of prepotent responses and memory monitoring/updating) by using a random-motor-generation task (MPT) in a group of 23 boys with Asperger syndrome (AS) and 23 matched healthy controls. We found poorer inhibition and more repetitive responses in younger AS children solely, but comparable memory monitoring/updating skills across groups. Overall, our findings correspond well with previous studies and reveal that even in AS specific EFs may improve with age and, thus, call for a more differentiated view of executive (dys) function profiles in children diagnosed with AS. Tests such as the random-motor-generation task may help to disentangle more specific processes of executive deficits in autism spectrum disorder as compared to the more classical tests.

Simulation modeling analysis of sequential relations among therapeutic alliance, symptoms, and adherence to child-centered play therapy between a child with autism spectrum disorder and two therapists

This study examined the sequential relations among three pertinent variables in child psychotherapy: therapeutic alliance (TA) (including ruptures and repairs), autism symptoms, and adherence to child-centered play therapy (CCPT) process. A 2-year CCPT of a 6-year-old Caucasian boy diagnosed with autism spectrum disorder was conducted weekly with two doctoral-student therapists, working consecutively for 1 year each, in a university-based community mental-health clinic. Sessions were video-recorded and coded using the Child Psychotherapy Process Q-Set (CPQ), a measure of the TA, and an autism symptom measure. Sequential relations among these variables were examined using simulation modeling analysis (SMA). In Therapist 1's treatment, unexpectedly, autism symptoms decreased three sessions after a rupture occurred in the therapeutic dyad. In Therapist 2's treatment, adherence to CCPT process increased 2 weeks after a repair occurred in the therapeutic dyad. The TA decreased 1 week after autism symptoms increased. Finally, adherence to CCPT process decreased 1 week after autism symptoms increased. The authors concluded that (1) sequential relations differ by therapist even though the child remains constant, (2) therapeutic ruptures can have an unexpected effect on autism symptoms, and (3) changes in autism symptoms can precede as well as follow changes in process variables.

Visual Form-Processing Deficits in Autism

People with autism have a number of reported deficits in object recognition and global processing. Is there a low-level spatial integration deficit associated with this? We measured spatial-form-coherence detection thresholds using a Glass stimulus in a field of random dots, and compared performance to a similar motion-coherence task. A coherent visual patch was depicted by dots separated by a rotational transformation in space (form) or space - time (motion). To measure parallel visual integration, stimuli were presented for only 250 ms. We compared detection thresholds for children with autism, children with Asperger syndrome, and a matched control group. Children with autism showed a significant form-coherence deficit and a significant motion-coherence deficit, while the performance of the children with Asperger syndrome did not differ significantly from that of controls on either task.

Autism spectrum disorder (ASD) and its perioperative management

Autism spectrum disorder (ASD) is now diagnosed in more than 1 in 100 children, so it is not surprising that anesthetists are increasingly providing care for children with this diagnosis. The diagnostic classification for ASD has recently changed and our understanding of the causes and management of ASD are also changing rapidly. This review provides a timely update to increase understanding and awareness of the problems that children with ASD experience, and to minimize perioperative problems. Current literature on premedication and the increasing use of alpha-2 agonists such as clonidine and dexmedetomidine as well as the use of old favorites midazolam and ketamine is reviewed. Some simple strategies that will improve care and decrease anxiety, like social stories, the use of tablet computers, other comfort items or games for distraction, and using favorite drinks to disguise the bitter taste of medications, are described. Remember, the parents are their child's expert and will know what agitates and settles them. Talking to them prior to the day of the procedure is ideal. The importance of staff training and having a clinical practice guideline available at every institution cannot be overstated.

Measuring the plasticity of social approach: a randomized controlled trial of the effects of the PEERS intervention on EEG asymmetry in adolescents with autism spectrum disorders

This study examined whether the Program for the Education and Enrichment of Relational Skills (PEERS: Social skills for teenagers with developmental and autism spectrum disorders: The PEERS treatment manual, Routledge, New York, 2010a) affected neural function, via EEG asymmetry, in a randomized controlled trial of adolescents with Autism spectrum disorders (ASD) and a group of typically developing adolescents. Adolescents with ASD in PEERS shifted from right-hemisphere gamma-band EEG asymmetry before PEERS to left-hemisphere EEG asymmetry after PEERS, versus a waitlist ASD group. Left-hemisphere EEG asymmetry was associated with more social contacts and knowledge, and fewer symptoms of autism. Adolescents with ASD in PEERS no longer differed from typically developing adolescents in left-dominant EEG asymmetry at post-test. These findings are discussed via the Modifier Model of Autism (Mundy et al. in Res Pract Persons Severe Disabl 32(2):124, 2007), with emphasis on remediating isolation/withdrawal in ASD.

Gait deviations in children with autism spectrum disorders: a review

In recent years, it has become clear that children with autism spectrum disorders (ASDs) have difficulty with gross motor function and coordination, factors which influence gait. Knowledge of gait abnormalities may be useful for assessment and treatment planning. This paper reviews the literature assessing gait deviations in children with ASD. Five online databases were searched using keywords “gait” and “autism,” and 11 studies were found which examined gait in childhood ASD. Children with ASD tend to augment their walking stability with a reduced stride length, increased step width and therefore wider base of support, and increased time in the stance phase. Children with ASD have reduced range of motion at the ankle and knee during gait, with increased hip flexion. Decreased peak hip flexor and ankle plantar flexor moments in children with ASD may imply weakness around these joints, which is further exhibited by a reduction in ground reaction forces at toe-off in children with ASD. Children with ASD have altered gait patterns to healthy controls, widened base of support, and reduced range of motion. Several studies refer to cerebellar and basal ganglia involvement as the patterns described suggest alterations in those areas of the brain. Further research should compare children with ASD to other clinical groups to improve assessment and treatment planning.

DSM-5 ASD moves forward into the past

The fifth edition of the diagnostic and statistical manual of mental disorders (DSM-5) (APA in diagnostic and statistical manual of mental disorders, Author, Washington, 2013) has decided to merge the subtypes of pervasive developmental disorders into a single category of autism spectrum disorder (ASD) on the assumption that they cannot be reliably differentiated from one another. The purpose of this review is to analyze the basis of this assumption by examining the comparative studies between Asperger's disorder (AsD) and autistic disorder (AD), and between pervasive developmental disorder not otherwise specified (PDDNOS) and AD. In all, 125 studies compared AsD with AD. Of these, 30 studies concluded that AsD and AD were similar conditions while 95 studies found quantitative and qualitative differences between them. Likewise, 37 studies compared PDDNOS with AD. Nine of these concluded that PDDNOS did not differ significantly from AD while 28 reported quantitative and qualitative differences between them. Taken together, these findings do not support the conceptualization of AD, AsD and PDDNOS as a single category of ASD. Irrespective of the changes proposed by the DSM-5, future research and clinical practice will continue to find ways to meaningfully subtype the ASD.

Asperger's disorder will be back

This review focuses on identifying up-to-date number of publications that compared DSM-IV/ICD-10 Asperger's disorder (AspD) to Autistic Disorder/High-functioning Autism (AD/HFA). One hundred and twenty-eight publications were identified through an extensive search of major electronic databases and journals. Based on more than 90 clinical variables been investigated, 94 publications concluded that there were statistically significant or near significant level of quantitative and/or qualitative differences between AspD and AD/HFA groups; 4 publications found both similarities and differences between the two groups; 30 publications concluded with no differences between the two groups. Although DSM-5 ASD will eliminate Asperger's disorder. However, it is plausible to predict that the field of ASD would run full circle during the next decade or two and that AspD will be back in the next edition of DSM.

Local and global aspects of biological motion perception in children born at very low birth weight

Biological motion perception can be assessed using a variety of tasks. In the present study, 8- to 11-year-old children born prematurely at very low birth weight (<1500 g) and matched, full-term controls completed tasks that required the extraction of local motion cues, the ability to perceptually group these cues to extract information about body structure, and the ability to carry out higher order processes required for action recognition and person identification. Preterm children exhibited difficulties in all 4 aspects of biological motion perception. However, intercorrelations between test scores were weak in both full-term and preterm children--a finding that supports the view that these processes are relatively independent. Preterm children also displayed more autistic-like traits than full-term peers. In preterm (but not full-term) children, these traits were negatively correlated with performance in the task requiring structure-from-motion processing, r(30) = -.36, p < .05), but positively correlated with the ability to extract identity, r(30) = .45, p < .05). These findings extend previous reports of vulnerability in systems involved in processing dynamic cues in preterm children and suggest that a core deficit in social perception/cognition may contribute to the development of the social and behavioral difficulties even in members of this population who are functioning within the normal range intellectually. The results could inform the development of screening, diagnostic, and intervention tools.

Quantification of changes in language-related brain areas in autism spectrum disorders using large-scale network analysis

PURPOSE

Diagnosis of autism spectrum disorders (ASD) is difficult, as symptoms vary greatly and are difficult to quantify objectively. Recent work has focused on the assessment of non-invasive diffusion tensor imaging-based biomarkers that reflect the microstructural characteristics of neuronal pathways in the brain. While tractography-based approaches typically analyze specific structures of interest, a graph-based large-scale network analysis of the connectome can yield comprehensive measures of larger-scale architectural patterns in the brain. Commonly applied global network indices, however, do not provide any specificity with respect to functional areas or anatomical structures. Aim of this work was to assess the concept of network centrality as a tool to perform locally specific analysis without disregarding the global network architecture and compare it to other popular network indices.

METHODS

We create connectome networks from fiber tractographies and parcellations of the human brain and compute global network indices as well as local indices for Wernicke's Area, Broca's Area and the Motor Cortex. Our approach was evaluated on 18 children suffering from ASD and 18 typically developed controls using magnetic resonance imaging-based cortical parcellations in combination with diffusion tensor imaging tractography.

RESULTS

We show that the network centrality of Wernicke's area is significantly (p<0.001) reduced in ASD, while the motor cortex, which was used as a control region, did not show significant alterations. This could reflect the reduced capacity for comprehension of language in ASD.

CONCLUSIONS

The betweenness centrality could potentially be an important metric in the development of future diagnostic tools in the clinical context of ASD diagnosis. Our results further demonstrate the applicability of large-scale network analysis tools in the domain of region-specific analysis with a potential application in many different psychological disorders.

Abnormalities in fronto-striatal connectivity within language networks relate to differences in grey-matter heterogeneity in Asperger syndrome

Asperger syndrome (AS) is an Autism Spectrum Disorder (ASD) characterised by qualitative impairment in the development of emotional and social skills with relative preservation of general intellectual abilities, including verbal language. People with AS may nevertheless show atypical language, including rate and frequency of speech production. We previously observed that abnormalities in grey matter homogeneity (measured with texture analysis of structural MR images) in AS individuals when compared with controls are also correlated with the volume of caudate nucleus. Here, we tested a prediction that these distributed abnormalities in grey matter compromise the functional integrity of brain networks supporting verbal communication skills. We therefore measured the functional connectivity between caudate nucleus and cortex during a functional neuroimaging study of language generation (verbal fluency), applying psycho-physiological interaction (PPI) methods to test specifically for differences attributable to grey matter heterogeneity in AS participants. Furthermore, we used dynamic causal modelling (DCM) to characterise the causal directionality of these differences in interregional connectivity during word production. Our results revealed a diagnosis-dependent influence of grey matter heterogeneity on the functional connectivity of the caudate nuclei with right insula/inferior frontal gyrus and anterior cingulate, respectively with the left superior frontal gyrus and right precuneus. Moreover, causal modelling of interactions between inferior frontal gyri, caudate and precuneus, revealed a reliance on bottom-up (stimulus-driven) connections in AS participants that contrasted with a dominance of top-down (cognitive control) connections from prefrontal cortex observed in control participants. These results provide detailed support for previously hypothesised central disconnectivity in ASD and specify discrete brain network targets for diagnosis and therapy in ASD.

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We used MRI techniques to assess the connectivity in language networks in AS.

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Grey-matter heterogeneity of MR images correlated with volume of caudate in AS.

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Hence, caudate nuclei were used as seed ROIs in connectivity analyses: PPI, DCM.

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Grey-matter heterogeneity differently tuned caudate connectivity in AS, controls.

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DCM of language circuitry featured bottom-up models in AS and top-down in controls.

Subgrouping the autism "spectrum": reflections on DSM-5

DSM-5 has moved autism from the level of subgroups ("apples and oranges") to the prototypical level ("fruit"). But making progress in research, and ultimately improving clinical practice, will require identifying subgroups within the autism spectrum.

mTOR Inhibition ameliorates cognitive and affective deficits caused by Disc1 knockdown in adult-born dentate granule neurons

Abnormalities during brain development are thought to cause psychiatric illness and other neurodevelopmental disorders. However, developmental processes such as neurogenesis continue in restricted brain regions of adults, and disruptions of these processes could contribute to the phenotypes of neurodevelopmental disorders. As previously reported, we show that Disc1 knockdown specifically in adult-born dentate gyrus (DG) neurons results in increased mTOR signaling, hyperexcitability, and neuronal structure deficits. Disc1 knockdown also resulted in pronounced cognitive and affective deficits, which could be reversed when the affected DG neurons were inactivated. Importantly, reversing increases in mTOR signaling with an FDA-approved inhibitor both prevented and treated these behavioral deficits, even when associated structural deficits were not reversed. Our findings suggest that a component of the affective and cognitive phenotypes in neurodevelopmental disorders may be caused by disruptions in adult-born neurons. Consequently, treatments directed at this cell population may have a significant impact on these phenotypes.

Management of Autism in the Adult Intensive Care Unit

Autism comprises a growing segment of the population and can be a management challenge in the intensive care unit (ICU). We present the case of a 22-year-old male with severe autism and intellectual disorder who developed respiratory failure and required a prolonged ICU course. This patient exhibited severe distress, aggression, and self-injurious behavior. Management challenges included sedation, weaning from sedation, and liberation from mechanical ventilation. Success was achieved with a multispecialty team and by tailoring the environment and interactions to the patient’s known preferences. The use of dexmedetomidine to wean high-dose benzodiazepines and opiates also permitted successful liberation from mechanical ventilation.

Relation between early motor delay and later communication delay in infants at risk for autism

BACKGROUND

Motor delays have been reported in retrospective studies of young infants who later develop Autism Spectrum Disorders (ASDs).

OBJECTIVE

In this study, we prospectively compared the gross motor development of a cohort at risk for ASDs; infant siblings of children with ASDs (AU sibs) to low risk typically developing (LR) infants.

METHODS

24 AU sibs and 24 LR infants were observed at 3 and 6 months using a standardized motor measure, the Alberta Infant Motor Scale (AIMS). In addition, as part of a larger study, the AU sibs also received a follow-up assessment to determine motor and communication performance at 18 months using the Mullen Scales of Early Learning.

RESULTS

Significantly more AU sibs showed motor delays at 3 and 6 months than LR infants. The majority of the AU sibs showed both early motor delays and later communication delays.

LIMITATIONS

Small sample size and limited follow-up.

CONCLUSIONS

Early motor delays are more common in AU sibs than LR infants. Communication delays later emerged in 67-73% of the AU sibs who had presented with early motor delays. Overall, early motor delays may be predictive of future communication delays in children at risk for autism.

Differential olfactory identification in children with autism and Asperger's disorder: a comparative and longitudinal study

Key theories of autism implicate orbitofrontal cortex (OFC) compromise, while olfactory identification (OI) deficits are associated with OFC dysfunction. This study aimed to complete a 5-year follow-up of children with high-functioning autism (HFA) who previously lacked the normal age-OI association; and compare unirhinal-OI in children with HFA, Asperger's disorder (ASP), and controls. While both HFA and controls had improved birhinal-OI at follow-up, reduced OI in some HFA participants suggested OFC deterioration and heterogeneous OFC development. Unirhinal-OI was impaired in HFA but not ASP relative to controls, suggesting orbitofrontal compromise in HFA but integrity in ASP. Differing IQ-OI relationships existed between HFA and ASP. Findings support the hypothesis of separate neurobiological underpinnings in ASP and HFA, specifically differential orbitofrontal functioning.

Current perspectives on motor functioning in infants, children, and adults with autism spectrum disorders

Autism spectrum disorders (ASDs) are the most common pediatric diagnoses in the United States. In this perspective article, we propose that a diverse set of motor impairments are present in children and adults with ASDs. Specifically, we will discuss evidence related to gross motor, fine motor, postural control, and imitation/praxis impairments. Moreover, we propose that early motor delays within the first 2 years of life may contribute to the social impairments of children with ASDs; therefore, it is important to address motor impairments through timely assessments and effective interventions. Lastly, we acknowledge the limitations of the evidence currently available and suggest clinical implications for motor assessment and interventions in children with ASDs. In terms of assessment, we believe that comprehensive motor evaluations are warranted for children with ASDs and infants at risk for ASDs. In terms of interventions, there is an urgent need to develop novel embodied interventions grounded in movement and motor learning principles for children with autism.

Greater disruption to control of voluntary saccades in autistic disorder than Asperger's disorder: evidence for greater cerebellar involvement in autism?

It remains unclear whether autism and Asperger's disorder (AD) exist on a symptom continuum or are separate disorders with discrete neurobiological underpinnings. In addition to impairments in communication and social cognition, motor deficits constitute a significant clinical feature in both disorders. It has been suggested that motor deficits and in particular the integrity of cerebellar modulation of movement may differentiate these disorders. We used a simple volitional saccade task to comprehensively profile the integrity of voluntary ocular motor behaviour in individuals with high functioning autism (HFA) or AD, and included measures sensitive to cerebellar dysfunction. We tested three groups of age-matched young males with normal intelligence (full scale, verbal, and performance IQ estimates >70) aged between 11 and 19 years; nine with AD, eight with HFA, and ten normally developing males as the comparison group. Overall, the metrics and dynamics of the voluntary saccades produced in this task were preserved in the AD group. In contrast, the HFA group demonstrated relatively preserved mean measures of ocular motricity with cerebellar-like deficits demonstrated in increased variability on measures of response time, final eye position, and movement dynamics. These deficits were considered to be consistent with reduced cerebellar online adaptation of movement. The results support the notion that the integrity of cerebellar modulation of movement may be different in AD and HFA, suggesting potentially differential neurobiological substrates may underpin these complex disorders.

Motor coordination in autism spectrum disorders: a synthesis and meta-analysis

Are motor coordination deficits an underlying cardinal feature of Autism Spectrum Disorders (ASD)? Database searches identified 83 ASD studies focused on motor coordination, arm movements, gait, or postural stability deficits. Data extraction involved between-group comparisons for ASD and typically developing controls (N = 51). Rigorous meta-analysis techniques including random effects models, forest and funnel plots, I (2), publication bias, fail-safe analysis, and moderator variable analyses determined a significant standardized mean difference effect equal to 1.20 (SE = 0.144; p <0.0001; Z = 10.49). This large effect indicated substantial motor coordination deficits in the ASD groups across a wide range of behaviors. The current overall findings portray motor coordination deficits as pervasive across diagnoses, thus, a cardinal feature of ASD.

Cortical gyrification in autistic and Asperger disorders: a preliminary magnetic resonance imaging study

The validity of Asperger disorder as a distinct syndrome from autism is unclear partly because of the paucity of differentiating neurobiological evidence. Frontal lobe cortical folding between these disorders was compared using the gyrification index. Twenty-three boys underwent structural magnetic resonance imaging: 6 with high-functioning autism, 9 with Asperger disorder, and 8 controls. Using the first coronal slice anterior to the corpus callosum, total and outer cortical contours were traced to calculate the gyrification index. This index was also calculated for superior and inferior regions to examine dorsolateral prefrontal and orbitofrontal cortices, respectively. Analysis of variance revealed differences in the left inferior gyrification index, which was higher in the autism group compared with Asperger and control groups. There were no differences in age, intelligence quotient, and brain volume. These preliminary findings suggest that cortical folding may be abnormally high in the frontal lobe in autism but not Asperger disorder, suggesting distinct frontal lobe neuropathology.

Right hemisphere dysfunction and metaphor comprehension in young adults with Asperger syndrome

This study examined whether the known difficulties in metaphor comprehension exhibited by persons with Asperger syndrome (AS) can be explained by a dysfunctional right hemisphere (RH). Using the divided visual field paradigm, 27 AS participants and 36 matched controls were presented with word pairs of four types (literal, conventional metaphors, novel metaphors, and unrelated word pairs), and were asked to perform a semantic judgment task. The main hypothesis was that whereas the control group participants will show RH superiority for novel metaphor processing, no RH superiority will be found in the AS group. Results indeed indicate much less RH contribution to novel metaphor comprehension in AS, and are discussed in light of linguistic models and the neurobiology of autism.

Judgements of self-understanding in adolescents with Asperger syndrome

Previous research has demonstrated that adults with high functioning autism (HFA)/Asperger syndrome (AS) judge others as having as much knowledge about their inner mental states as they do. The current study examined whether this pattern also applies to adolescents with HFA/AS because typically developing adolescents, in contrast to younger children, regard themselves as experts on their own inner states. Twenty-two adolescents with HFA/AS and 22 controls judged how much they versus a comparison person knew about 6 aspects of their inner states. In contrast to typically developing adolescents, those with HFA/AS judged the comparison person as having more knowledge about themselves than they did. This study suggests that adolescents with HFA/AS have more pronounced difficulties with this aspect of self-knowledge than do adults with this condition. The implications of this deficit for social functioning are discussed.

A preliminary transcranial magnetic stimulation study of cortical inhibition and excitability in high-functioning autism and Asperger disorder

AIM

Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS).

METHOD

Participants were diagnosed by experienced clinicians strictly according to DSM-IV criteria. Participants with HFA (nine males, two females; mean age 16y 8mo, SD 4y 5mo) or Asperger disorder (11 males, three females; mean age 19y 1mo, SD 4y 2mo) and neurotypical participants (eight males, three females; mean age 19y 0mo, SD 3y 1mo) were administered a paired-pulse TMS paradigm intended to assess motor cortical inhibition and excitability. Responses to TMS were recorded by electromyography.

RESULTS

Cortical inhibition was significantly reduced in the HFA group compared with both the Asperger disorder (p<0.001) and neurotypical (p<0.001) groups, suggesting disruption of activity at gamma-aminobutyric acid A (GABA(A)) receptors. There was no group difference in cortical excitability.

INTERPRETATION

Cortical inhibition deficits may underlie motor dysfunction in autism, and perhaps even relate to specific clinical symptoms (e.g. repetitive behaviours). These findings provide novel evidence for a possible neurobiological dissociation between HFA and Asperger disorder based on GABAergic function.

Clinical and anatomical heterogeneity in autistic spectrum disorder: a structural MRI study

BACKGROUND

Autistic spectrum disorder (ASD) is characterized by stereotyped/obsessional behaviours and social and communicative deficits. However, there is significant variability in the clinical phenotype; for example, people with autism exhibit language delay whereas those with Asperger syndrome do not. It remains unclear whether localized differences in brain anatomy are associated with variation in the clinical phenotype.

METHOD

We used voxel-based morphometry (VBM) to investigate brain anatomy in adults with ASD. We included 65 adults diagnosed with ASD (39 with Asperger syndrome and 26 with autism) and 33 controls who did not differ significantly in age or gender.

RESULTS

VBM revealed that subjects with ASD had a significant reduction in grey-matter volume of medial temporal, fusiform and cerebellar regions, and in white matter of the brainstem and cerebellar regions. Furthermore, within the subjects with ASD, brain anatomy varied with clinical phenotype. Those with autism demonstrated an increase in grey matter in frontal and temporal lobe regions that was not present in those with Asperger syndrome.

CONCLUSIONS

Adults with ASD have significant differences from controls in the anatomy of brain regions implicated in behaviours characterizing the disorder, and this differs according to clinical subtype.

Motor coordination in autism spectrum disorders: a synthesis and meta-analysis

Are motor coordination deficits an underlying cardinal feature of Autism Spectrum Disorders (ASD)? Database searches identified 83 ASD studies focused on motor coordination, arm movements, gait, or postural stability deficits. Data extraction involved between-group comparisons for ASD and typically developing controls (N = 51). Rigorous meta-analysis techniques including random effects models, forest and funnel plots, I (2), publication bias, fail-safe analysis, and moderator variable analyses determined a significant standardized mean difference effect equal to 1.20 (SE = 0.144; p <0.0001; Z = 10.49). This large effect indicated substantial motor coordination deficits in the ASD groups across a wide range of behaviors. The current overall findings portray motor coordination deficits as pervasive across diagnoses, thus, a cardinal feature of ASD.

Neuropsychological mechanisms of Digit Symbol Substitution Test impairment in Asperger Disorder

Our aim was to investigate the neurocognitive mechanisms recruited by adolescents with Asperger Disorder (AD), in comparison to controls, and to detect the underlying mechanisms during the complex information processing required for the performance of the Digit Symbol Substitution Test (DSST). Male adolescents (n=23; mean age 15.1+/-3.6 years) with a DSM-IV diagnosis of AD were compared with a normal male control group with similar demographic characteristics (n=43; mean age: 15.1+/-3.6 years). A computerized neurocognitive battery was administered and included: Inspection Time (IT), Finger Tapping Test (FTT), Simple Reaction Time (SRT), Choice Reaction Time (CRT), Digit Running task (DRT), Stroop test and Digit Symbol Substitution Test (DSST). Adolescents with AD performed significantly worse than controls on the DSST. This impaired DSST performance was related to cognitive mechanisms different from those employed by normal controls. Motor slowness and inability to deal with increased amounts of information affected the performance of the AD group, while shifting of attention was the limiting factor in the controls. Both groups were similarly dependent on response selection. This study demonstrated differences in performance in complex cognitive tasks between adolescents with AD and normal controls that may be related to differences in neurocognitive mechanisms underlying information processing. Future neuroimaging studies are needed to clarify the neural network involved in the differences in cognitive performance between AD subjects and normal controls.

Cognitive differences in pictorial reasoning between high-functioning autism and Asperger's syndrome

We investigated linguistic and visuospatial processing during pictorial reasoning in high-functioning autism (HFA), Asperger's syndrome (ASP), and age and IQ-matched typically developing participants (CTRL), using three conditions designed to differentially engage linguistic mediation or visuospatial processing (visuospatial, V; semantic, S; visuospatial + semantic, V + S). The three groups did not differ in accuracy, but showed different response time profiles. ASP and CTRL participants were fastest on V + S, amenable to both linguistic and nonlinguistic mediation, whereas HFA participants were equally fast on V and V + S, where visuospatial strategies were available, and slowest on S. HFA participants appeared to favor visuospatial over linguistic mediation. The results support the use of linguistic versus visuospatial tasks for characterizing subtypes on the autism spectrum.

Distinct patterns of grey matter abnormality in high-functioning autism and Asperger's syndrome

BACKGROUND

Autism exists across a wide spectrum and there is considerable debate as to whether children with Asperger's syndrome, who have normal language milestones, should be considered to comprise a subgroup distinct other from high-functioning children with autism (HFA), who have a history of delayed language development. Magnetic resonance imaging (MRI) studies of autism are in disagreement. One possible reason is that the diagnosis of autism takes precedence over Asperger's syndrome and a distinction in language acquisition is rarely made. We therefore planned to examine a whole brain hypothesis that the patterns of grey matter differences in Asperger's syndrome and HFA can be distinguished.

METHODS

We used voxel-based computational morphometry to map grey matter volume differences in 33 children with either Asperger's syndrome or high-functioning autism compared to 55 typical developing control children balanced for age, IQ, gender, maternal language and ethnicity.

RESULTS

Children with HFA had significantly smaller grey matter volumes in subcortical, posterior cingulate and precuneus regions than the Asperger's group. Compared to controls, children with HFA had smaller grey matter volumes in predominantly fronto-pallidal regions, while children with Asperger's had less grey matter in mainly bilateral caudate and left thalamus. In addition we found a significant negative correlation between the size of a grey matter cluster around BA44 language area and the age of acquisition of phrase speech in the children with HFA. When the groups were combined we confirmed a mixed picture of smaller grey matter volumes in frontal, basal ganglia, temporal and parietal regions.

CONCLUSIONS

Our study suggests that the underlying neurobiology in HFA and Asperger's syndrome is at least partly discrete. Future studies should therefore consider the history of language acquisition as a valuable tool to refine investigation of aetiological factors and management options in pervasive developmental disorders.

Psychosis and autism as diametrical disorders of the social brain

Autistic-spectrum conditions and psychotic-spectrum conditions (mainly schizophrenia, bipolar disorder, and major depression) represent two major suites of disorders of human cognition, affect, and behavior that involve altered development and function of the social brain. We describe evidence that a large set of phenotypic traits exhibit diametrically opposite phenotypes in autistic-spectrum versus psychotic-spectrum conditions, with a focus on schizophrenia. This suite of traits is inter-correlated, in that autism involves a general pattern of constrained overgrowth, whereas schizophrenia involves undergrowth. These disorders also exhibit diametric patterns for traits related to social brain development, including aspects of gaze, agency, social cognition, local versus global processing, language, and behavior. Social cognition is thus underdeveloped in autistic-spectrum conditions and hyper-developed on the psychotic spectrum.;>We propose and evaluate a novel hypothesis that may help to explain these diametric phenotypes: that the development of these two sets of conditions is mediated in part by alterations of genomic imprinting. Evidence regarding the genetic, physiological, neurological, and psychological underpinnings of psychotic-spectrum conditions supports the hypothesis that the etiologies of these conditions involve biases towards increased relative effects from imprinted genes with maternal expression, which engender a general pattern of undergrowth. By contrast, autistic-spectrum conditions appear to involve increased relative bias towards effects of paternally expressed genes, which mediate overgrowth. This hypothesis provides a simple yet comprehensive theory, grounded in evolutionary biology and genetics, for understanding the causes and phenotypes of autistic-spectrum and psychotic-spectrum conditions.

Brief report: Inhibition of return in young people with autism and Asperger's disorder

The aim of this study was to investigate whether the superior search abilities observed in autism/Asperger's disorder may in part be a consequence of a more pronounced inhibition of return (IOR). Contrary to our prediction, IOR in individuals with autism was comparable to the matched comparison group. However, the autism group committed more false alarm responses than the matched comparison group; this may reflect a possible inhibitory deficit, or suggest that individuals with autism rely more on probabilities to determine their behavioural responses. There was a borderline-significant trend ( p = 0.052) to indicate that IOR may be more pronounced in individuals with Asperger's disorder. In contrast to the autism group, the Asperger's disorder group had a pattern of false alarm responses similar to that of the comparison group. The findings further inform Minshew's complex information processing theory which seeks to establish which areas of neuropsychological functioning are preserved and deficit in autism.

Comparison of form and motion coherence processing in autistic spectrum disorders and dyslexia

A large body of research has reported visual perception deficits in both people with dyslexia and autistic spectrum disorders. In this study, we compared form and motion coherence detection between a group of adults with high-functioning autism, a group with Asperger's disorder, a group with dyslexia, and a matched control group. It was found that motion detection was intact in dyslexia and Asperger. Individuals with high-functioning autism showed a general impaired ability to detect coherent form and motion. Participants with Asperger's syndrome showed lower form coherence thresholds than the dyslexic and normally developing adults. The results are discussed with respect to the involvement of the dorsal and ventral pathways in developmental disorders.

Prevalence of motor impairment in autism spectrum disorders

Autism spectrum disorders (ASD) are manifest as impairments in social interaction, language and speech development, and the appearance of repetitive behaviors with restricted interests. Motor impairments in individuals with ASD have been categorized as "associated symptoms". The objective of this study was to describe the prevalence of motor deficits in ASD. Specifically, using retrospective clinical record review, we report the prevalence of hypotonia, motor apraxia, reduced ankle mobility, history of gross motor delay, and toe-walking, as well as the improvement of these symptoms with age, in a cohort of 154 children with ASD. The possible association of motor deficits with epilepsy or developmental regression was also assessed. To address whether the motor deficits in children with ASD were properly identified and treated, we evaluated whether the children with the motor deficits were more likely to receive physical and/or occupational therapies as compared to the children with ASD who did not show motor deficits. Hypotonia was the most common motor symptom in our ASD cohort (51%) and this appeared to improve over time, as suggested by the significant reduction in prevalence in older children (p=0.002). Likewise, motor apraxia (34%) showed a tendency to be more prevalent among younger children as compared with older children (p=0.06). Historical intermittent toe-walking was found in 19% of children while reduced ankle mobility was a rare occurrence. Gross motor delay was reported in 9% of children, all of whom gained motor independence by the time of examination. Except for gross motor delay, ASD children with fine motor deficits were not more likely to receive interventional services, as compared with ASD children without the motor deficits. The results suggest that fine motor control and programming deficits are common co-occurrence of children with ASD in this cohort. The reduced prevalence of these motor deficits in older children suggests improvement over time, whether through natural progression, results of interventional therapy, or the combination of the two. However, ASD children with the motor deficits were not more likely to receive service than those without the motor deficits.

WISC-IV and WIAT-II Profiles in Children With High-Functioning Autism

Children with high-functioning autism earned above normal scores on the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) Perceptual Reasoning and Verbal Comprehension Indexes and below normal scores on the Working Memory and Processing Speed Indexes and Wechsler Individual Achievement Test-Second Edition (WIAT-II) Written Expression. Full Scale IQ (FSIQ) and reading and math scores were similar to the norm. Profiles were consistent with previous WISC-III research, except that the new WISC-IV motor-free visual reasoning subtests (Matrix Reasoning and Picture Concepts) were the highest of the nonverbal subtests. The WISC-IV may be an improvement over the WISC-III for children with high-functioning autism because it captures their visual reasoning strength, while identifying their attention, graphomotor, and processing speed weaknesses. FSIQ was the best single predictor of academic achievement.

Neuropsychological functioning in adults with Asperger syndrome

There is some consensus in the literature regarding the cognitive profile of people with Asperger syndrome (AS). Findings to date suggest that a proportion of people with AS have higher verbal than performance IQ, a non-verbal learning disability (NVLD) and impairments in some aspects of executive function (EF). However, there are few published studies on adults with AS and many have compared the AS group to an autistic control group alone. We compared cognitive functioning in 27 AS adults without a history of language delay and 20 normal controls who did not differ significantly in age, gender and IQ. People with AS had significant impairments on a test of visual memory and on EF tasks measuring flexibility and generativity, but not inhibition. There was no significant difference between verbal and performance IQ. Our results suggest that impairments on tests requiring flexibility of thought and generation occur at all ages and across a range of autistic disorders including AS.

The Role of Early Auditory Discrimination Deficits in Language Disorders

Language impairments can have a devastating effect on the individual’s life. Brain damage such as stroke may cause varying degrees of impaired language. Even milder language problems, such as developmental dyslexia or specific language impairment, can have long-lasting detrimental effects on the individual’s life, affecting both success at school as well as motivation and even self-esteem. In recent years, the mismatch negativity (MMN) has been intensively applied to study the neural basis of language impairments. These studies have shown that the MMN, which reflects the early stages of cortical sound discrimination, is abnormal in a large variety of language impairments. Furthermore, a close relationship between the MMN and some language disorders is suggested by significant correlations between the MMN and language test results. Further support is provided by follow-up studies suggesting that the MMN parameters may predict future language problems in children and by investigations indicating that intervention programs with an ameliorating effect also concurrently change the MMN. However, when interpreting the implications of MMN results it is important to acknowledge that this response specifically reflects early stages of auditory discrimination and should, therefore, be combined with measures probing the further steps of auditory processing for a more complete picture of the underlying deficits of language. The current review addresses how the MMN can be used in determining auditory impairments in language disorders such as aphasia, dyslexia, autism spectrum, and specific language impairment.

Medicaid expenditures for children with autistic spectrum disorders: 1994 to 1999

This study used data from 1994 to 1999 from one large county in Pennsylvania to estimate the Medicaid expenditures of children diagnosed with autism spectrum disorders (ASD) and to compare these expenditures with those of other Medicaid-eligible children. On average, children diagnosed with ASD had expenditures 10 times those of other children. Differences in expenditures were driven in large part by inpatient psychiatric care. Further research is required to determine whether hospitalized children could be served in less restrictive and less expensive settings. Lack of differences in ambulatory care expenditures suggests that children with ASD are not receiving additional primary care services that would be indicative of appropriately coordinated services as suggested by the medical home model.

Two terms--one meaning: the conundrum of contemporary nomenclature in autism

TOPIC

Autism as a diagnostic construct in the last decade has undergone a process of rapid evolution in the way that it is operationalized. A by-product of the important conceptual shift is that we have been left with two terms, autistic disorder and Asperger's disorder, that point to the same thing. The existence of two terms that cannot be clearly delineated results in confusion and an added element in an already anxiety-laden mix for all those trying to come to terms with the concept of autism.

PURPOSE

This paper moves beyond contemporary arguments of whether autistic disorder and Asperger's disorder are different entities and uses a case study to consider the mechanism of the confusion caused, and highlight the importance of referent clarity.

SOURCES

A review of sources in journals and texts related to the topic is included to complement the progressive review of the case study as the clients move through a 1-hour initial consult.

CONCLUSION

The current diagnostic criteria are ambiguous posing the risk of confusion to parents, clinicians, and researchers. Nurses have an important role in assisting parents' construction of a unified concept of autism clinically, and through research. This paper moves beyond merely acknowledging the confusion that exists by considering the nature of the confusion, and through sharing the experience of one possible way of navigating it.

Social attribution processes and comorbid psychiatric symptoms in children with Asperger syndrome

The factors that place children with Asperger syndrome at risk for comorbid psychiatric symptoms, such as anxiety and depression, remain poorly understood. We investigated the possibility that the children's emotional and behavioral difficulties are associated with social information and attribution processing. Participants were children with either Asperger syndrome (n = 31) or typical development (n = 33).To assess social information and attribution processing, children responded to hypothetical social vignettes. They also completed self-report measures of social difficulties and psychological functioning. Their parents provided information on social competence and clinical presentation. Children with Asperger syndrome showed poor psychosocial adjustment, which was related to their social information and attribution processing patterns. Cognitive and social-cognitive abilities were associated with aspects of social information processing tendencies, but not with emotional and behavioral difficulties. Results suggest that the comorbid symptoms of children with Asperger syndrome may be associated with their social perception, understanding, and experience.

Imbalanced genomic imprinting in brain development: an evolutionary basis for the aetiology of autism

We describe a new hypothesis for the development of autism, that it is driven by imbalances in brain development involving enhanced effects of paternally expressed imprinted genes, deficits of effects from maternally expressed genes, or both. This hypothesis is supported by: (1) the strong genomic-imprinting component to the genetic and developmental mechanisms of autism, Angelman syndrome, Rett syndrome and Turner syndrome; (2) the core behavioural features of autism, such as self-focused behaviour, altered social interactions and language, and enhanced spatial and mechanistic cognition and abilities, and (3) the degree to which relevant brain functions and structures are altered in autism and related disorders. The imprinted brain theory of autism has important implications for understanding the genetic, epigenetic, neurological and cognitive bases of autism, as ultimately due to imbalances in the outcomes of intragenomic conflict between effects of maternally vs. paternally expressed genes.