Brief report: abnormal association between the thalamus and brain size in Asperger's disorder.
ABSTRACT The objective of this study was to examine the relationship between thalamic volume and brain size in individuals with Asperger's disorder (ASP). Volumetric measurements of the thalamus were performed on MRI scans obtained from 12 individuals with ASP (age range: 10-35 years) and 12 healthy controls (age range: 9-33 years). A positive correlation was found between total brain volume and thalamic size in controls, but not in ASP subjects. This occurred in the absence of differences in mean thalamic volumes between the study groups. Findings from this investigation point to an abnormal relationship between the thalamus and its projection areas in ASP and are consistent with similar studies in autism, supporting that these disorders are qualitatively similar and possibly quantitatively different.
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ABSTRACT: This systematic review aims to determine whether or not structural magnetic resonance imaging (sMRI) data support the DSM-5 proposal of an autism spectrum disorder (ASD) diagnostic category, and whether or not classical DSM-IV autistic disorder (AD) and Asperger syndrome (AS) categories should be subsumed into it. The most replicated sMRI findings in patients with ASD compared with healthy controls are increased total brain volume in early childhood and decreased corpus callosum volume. Regarding the notion of a spectrum, some studies support that AS and AD are similar but “quantitatively different” diagnostic categories, whereas others support that they are “qualitatively different” entities with specific brain structural abnormalities. It seems that there are still not enough arguments from sMRI data for or against subsuming DSM-IV categories under a single ASD category.Research in Autism Spectrum Disorders 02/2013; 7(2):333–343. · 2.96 Impact Factor
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ABSTRACT: Autism spectrum disorders (ASD) display significant heterogeneity. Although most neuroimaging studies in ASD have been designed to identify commonalities among affected individuals, rather than differences, some studies have explored variation within ASD. There have been two general types of approaches used for this in the neuroimaging literature to date: comparison of subgroups within ASD, and analyses using dimensional measures to link clinical variation to brain differences. This review focuses on structural and functional magnetic resonance imaging studies that have used these approaches to begin to explore heterogeneity between individuals with ASD. Although this type of data is yet sparse, recognition is growing of the limitations of behaviorally defined categorical diagnoses for understanding neurobiology. Study designs that are more informative regarding the sources of heterogeneity in ASD have the potential to improve our understanding of the neurobiological processes underlying ASD.Frontiers in Human Neuroscience 01/2013; 7:733. · 2.91 Impact Factor
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ABSTRACT: Thalamic abnormalities have been reported in people with pervasive developmental disorders (PDD) including Asperger's Disorder (ASP). The aim of the present study was to compare the volume and volume fraction of the thalamus and the metabolite concentrations in children and adolescents with ASP using the magnetic resonance imaging and proton magnetic resonance spectroscopy. Additionally, the relationships between thalamic abnormalities and clinical features were examined.Psychiatry investigation 07/2014; 11(3):237-42. · 1.06 Impact Factor