Brain enlargement has been observed in children with autism spectrum disorder (ASD), but the timing of this phenomenon, and the relationship between ASD and the appearance of behavioural symptoms, ...are unknown. Retrospective head circumference and longitudinal brain volume studies of two-year olds followed up at four years of age have provided evidence that increased brain volume may emerge early in development. Studies of infants at high familial risk of autism can provide insight into the early development of autism and have shown that characteristic social deficits in ASD emerge during the latter part of the first and in the second year of life. These observations suggest that prospective brain-imaging studies of infants at high familial risk of ASD might identify early postnatal changes in brain volume that occur before an ASD diagnosis. In this prospective neuroimaging study of 106 infants at high familial risk of ASD and 42 low-risk infants, we show that hyperexpansion of the cortical surface area between 6 and 12 months of age precedes brain volume overgrowth observed between 12 and 24 months in 15 high-risk infants who were diagnosed with autism at 24 months. Brain volume overgrowth was linked to the emergence and severity of autistic social deficits. A deep-learning algorithm that primarily uses surface area information from magnetic resonance imaging of the brain of 6-12-month-old individuals predicted the diagnosis of autism in individual high-risk children at 24 months (with a positive predictive value of 81% and a sensitivity of 88%). These findings demonstrate that early brain changes occur during the period in which autistic behaviours are first emerging.
El presente estudio tiene una doble finalidad. La primera es analizar dos de las variables implicadas en la comprensión de las meteduras de pata (MP) en el autismo (Cociente Intelectual; CI, y la ...Falsa Creencia; FC). La segunda, examinar en detalle las dificultades encontradas en la tarea de MP, dividida la población con autismo en dos grupos según su CI (Grupo 1= rango CI 100-120, Grupo 2 = rango CI 70-85). De dicha tarea de MP, se adaptaron cuatro historias (viñetas y narración) de Baron-Cohen, O'Riordan, Stone, Jones y Plaisted (1999), y se administraron a los dos grupos de niños y pre-adolescente con autismo (N = 34) de entre 7 y 12 años (M = 9.6, DE = 1.55), que las resolvieron a partir de respuestas de elección dicotómica y de explicación verbal. Los resultados demuestran la capacidad predictiva del CI total (r = 0.53; p < 0.001; R.sup.2 = 0.28) y de la FC (r = 0.51; p < 0.001; R2 = 0.26). El 40 % de la variabilidad de la tarea de MP se vio explicada por las variables predictores FC y Vocabulario. Además, se encontraron diferencias significativas entre grupos (el Grupo 1 respondió mejor que el Grupo 2) tanto en respuestas de elección forzada personaje (ii) e ignorancia (vii) y la suma total como en su explicación verbal. Estos resultados se discuten más detalladamente debido a su posible repercusión en la vida diaria de las personas con autismo. Palabras clave metedura de pata; teoría de la mente; autismo; falsa creencia; inteligencia. The present study has a double purpose. The first is to analyse two of the variables involved in the understanding of the faux pas in autism (Intelligence Quotient--IQ--and False Belief--FB). The second is to examine in detail the difficulties encountered in the Faux Pas test, when autistic individuals were divided into two groups according to their IQ (Group 1 = IQ range 100--120, Group 2 = IQ range 70--85). Four stories from the Faux Pas test (Baron-Cohen, O'Riordan, Stone, Jones, & Plaisted, 1999) were adapted (vignettes and narration in Spanish), and two groups of autistic children (N = 34) between 7 and 12 years of age (M = 9.6, SD = 1.55) responded through forced-choice answers and verbal explanations. The results demonstrated the predictive capacity of full-scale IQ (r = 0.53; p < 0.001; R.sup.2 = 0.28) and FB (r = 0.51; p < 0.001; R.sup.2 = 0.26) in the performance of the Faux Pas test. Verbal IQ and FB could explain 40% of the variability in the results of the Faux Pas test. Significant differences were found overall in the forced-choice responses, and more specifically in ii) the recognition of the speaker, and vii) the ignorance of the information, as well as in their verbal explanations. Findings are discussed in depth due to their possible impact on the daily lives of autistic individuals. Keywords faux pas; theory of mind; autism; false belief; intelligence.
There is an emerging body of evidence linking the intestinal microbiota with autism spectrum disorders (ASD). Studies have demonstrated differences in the composition of gut bacteria between children ...with ASD and controls. Certain intestinal bacteria have been observed in abundance and may be involved in the pathogenesis of ASD; including members of the
Clostridium
and
Sutterella
genus. Evidence from animal models suggest that certain microbial shifts in the gut may produce changes consistent with the clinical picture of autism, with proposed mechanisms including toxin production, aberrations in fermentation processes/products, and immunological and metabolic abnormalities. In this article, we review studies examining the relationship between intestinal bacteria and ASD, and discuss bacterial species that may be implicated and proposed mechanisms.
"What does it mean to say that someone is autistic? Towards an Ethics of Autism is an exploration of this question and many more. In this thoughtful, wide-ranging book, Kristien Hens examines a ...number of perspectives on autism, including psychiatric, biological, and philosophical, to consider different ways of thinking about autism, as well as its meanings to those who experience it, those who diagnose it, and those who research it. Hens delves into the history of autism and its roots in the work of Leo Kanner and Hans Asperger to inform a contemporary ethical analysis of the models we use to understand autism today. She explores the various impacts of a diagnosis on autistic people and their families, the relevance of disability studies, the need to include autistic people fully in discussions about (and research on) autism, and the significance of epigenetics to future work on autism. Hens weaves together a variety of perspectives that guide the reader in their own ethical reflections about autism. Rich, accessible, and multi-layered, this is essential reading for philosophers, educational scientists, and psychologists who are interested in philosophical-ethical questions related to autism, but it also has much to offer to teachers, allied health professionals, and autistic people themselves. "
The reasons behind the increase in autism diagnoses have become hotly contested in the media as well as within the medical, scholarly, and autistic communities. In Autism and Gender: From ...Refrigerator Mothers to Computer Geeks, Jordynn Jack focuses on the ways gender influences popular discussion and understanding of autism's causes and effects. She identifies gendered theories like the “refrigerator mother†theory, for example, which blames emotionally distant mothers for autism, and the “extreme male brain†theory, which links autism to the modes of systematic thinking found in male computer geeks. Jack's analysis reveals how people employ highly gendered theories to craft rhetorical narratives around stock characters--fix-it dads, heroic mother warriors rescuing children from autism--that advocate for ends beyond the story itself while also allowing the storyteller to gain authority, understand the disorder, and take part in debates. The first book to look at how gender informs popular discussion about autism, Autism and Gender also offers new insights into the ways rhetorical inquiry can and does contribute to conversations about gender and disability.
Autism spectrum disorder (ASD) has a major impact on the development and social integration of affected individuals and is the most heritable of psychiatric disorders. An increase in the incidence of ...ASD cases has prompted a surge in research efforts on the underlying neuropathologic processes. We present an overview of current findings in neuropathology studies of ASD using two investigational approaches, postmortem human brains and ASD animal models, and discuss the overlap, limitations, and significance of each. Postmortem examination of ASD brains has revealed global changes including disorganized gray and white matter, increased number of neurons, decreased volume of neuronal soma, and increased neuropil, the last reflecting changes in densities of dendritic spines, cerebral vasculature and glia. Both cortical and non-cortical areas show region-specific abnormalities in neuronal morphology and cytoarchitectural organization, with consistent findings reported from the prefrontal cortex, fusiform gyrus, frontoinsular cortex, cingulate cortex, hippocampus, amygdala, cerebellum and brainstem. The paucity of postmortem human studies linking neuropathology to the underlying etiology has been partly addressed using animal models to explore the impact of genetic and non-genetic factors clinically relevant for the ASD phenotype. Genetically modified models include those based on well-studied monogenic ASD genes (
NLGN3
,
NLGN4
,
NRXN1
,
CNTNAP2
,
SHANK3
,
MECP2
,
FMR1
,
TSC1/2
), emerging risk genes (
CHD8
,
SCN2A
,
SYNGAP1
,
ARID1B
,
GRIN2B
,
DSCAM
,
TBR1
), and copy number variants (15q11-q13 deletion, 15q13.3 microdeletion, 15q11-13 duplication, 16p11.2 deletion and duplication, 22q11.2 deletion). Models of idiopathic ASD include inbred rodent strains that mimic ASD behaviors as well as models developed by environmental interventions such as prenatal exposure to sodium valproate, maternal autoantibodies, and maternal immune activation. In addition to replicating some of the neuropathologic features seen in postmortem studies, a common finding in several animal models of ASD is altered density of dendritic spines, with the direction of the change depending on the specific genetic modification, age and brain region. Overall, postmortem neuropathologic studies with larger sample sizes representative of the various ASD risk genes and diverse clinical phenotypes are warranted to clarify putative etiopathogenic pathways further and to promote the emergence of clinically relevant diagnostic and therapeutic tools. In addition, as genetic alterations may render certain individuals more vulnerable to developing the pathological changes at the synapse underlying the behavioral manifestations of ASD, neuropathologic investigation using genetically modified animal models will help to improve our understanding of the disease mechanisms and enhance the development of targeted treatments.
Growing awareness that symptoms of autism spectrum disorder (ASD) transcend multiple diagnostic categories, and major advances in the identification of genetic syndromes associated with ASD, have led ...to widespread use of ASD symptom measures in etiologic studies of neurodevelopmental disorders. Insufficient consideration of potentially confounding factors such as cognitive ability or behavior problems can have important negative consequences in interpretation of findings, including erroneous estimation of associations between ASD and etiologic factors.
Participants were 388 children 2 to 13 years old with diagnoses of ASD or another neurodevelopmental disorder without ASD. Receiver operating characteristics methods were used to assess the influence of IQ and emotional and behavioral problems on the discriminative ability of 3 widely used ASD symptom measures: the Social Responsiveness Scale (SRS), the Autism Diagnostic Interview-Revised (ADI-R), and the Autism Diagnostic Observation Schedule (ADOS).
IQ influenced the discriminative thresholds of the SRS and ADI-R, and emotional and behavioral problems affected the discriminative thresholds of the SRS, ADI-R, and ADOS. This resulted in low specificity of ASD cutoffs on the SRS and ADI-R for children with intellectual disability without ASD (27-42%) and low specificity across all 3 instruments for children without ASD with increased emotional and behavioral problems (36-59%). Adjustment for these characteristics resulted in improved discriminative ability for all of the ASD measures.
The findings indicate that scores on ASD symptom measures reflect far more than ASD symptoms. Valid interpretation of scores on these measures requires steps to account for the influences of IQ and emotional and behavioral problems.
Autism is a neurodevelopmental disorder characterized by deficits in communication and social skills as well as repetitive and stereotypical behaviors. While much effort has focused on the ...identification of genes associated with autism, research emerging within the past two decades suggests that immune dysfunction is a viable risk factor contributing to the neurodevelopmental deficits observed in autism spectrum disorders (ASD). Further, it is the heterogeneity within this disorder that has brought to light much of the current thinking regarding the subphenotypes within ASD and how the immune system is associated with these distinctions. This review will focus on the two main axes of immune involvement in ASD, namely dysfunction in the prenatal and postnatal periods. During gestation, prenatal insults including maternal infection and subsequent immunological activation may increase the risk of autism in the child. Similarly, the presence of maternally derived anti-brain autoantibodies found in ~20% of mothers whose children are at risk for developing autism has defined an additional subphenotype of ASD. The postnatal environment, on the other hand, is characterized by related but distinct profiles of immune dysregulation, inflammation, and endogenous autoantibodies that all persist within the affected individual. Further definition of the role of immune dysregulation in ASD thus necessitates a deeper understanding of the interaction between both maternal and child immune systems, and the role they have in diagnosis and treatment.
PDF
