Quantitative magnetic resonance image analysis of the cerebellum in macrocephalic and normocephalic children and adults with autism.
ABSTRACT A detailed morphometric analysis of the cerebellum in autism with and without macrocephaly. Four subject groups (N = 65; male; IQs > or = 65; age 7 to 26 years) were studied with quantitative MRI; normocephalic and macrocephalic individuals with autism without mental retardation were compared to normocephalic and benign macrocephalic typically developing individuals. Total cerebellum volumes and surface areas of four lobular midsagittal groups were measured. Independent t-tests between autism and control subjects matched for head size revealed no significant differences. Multivariate analyses of variance were also performed, using the diagnostic group as the fixed factor, cerebellar measures as the dependent variables and total intracranial volume, total brain volume, age, verbal IQ, and performance IQ as covariates. No significant differences were found; however, a trend was noted in which macrocephalic individuals with autism consistently exhibited slightly smaller cerebellar volume or surface area when compared to individuals with benign macrocephaly. In autism, with and without macrocephaly, cerebellar structures were found to be proportional to head size and did not differ from typically developing subjects.
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ABSTRACT: Autism Spectrum Disorder (ASD) is a group of behaviourally defi ned neurodevelopmental disorders of childhood onset characterised by impairments in communication and social reciprocity as well as a range of distinctive non-social symptoms. Despite including some of the most heritable disorders in psychiatry, it has proved difficult to identify risk genes for ASD, and to build models for the neurobiological mechanisms through which putative risk factors might operate to give rise to the ASD behavioural phenotype. In this chapter we detail why measures of brain anatomy derived from structural magnetic resonance images have been put forward as potential alternative endophenotypes that might increase our ability to identify risk genes and associated brain mechanisms for ASD. We then examine the progress that has been made so far in identifying neurostructural endophenotypes for ASD, and consider some of the challenges and opportunities presented by this new line of research in ASD neurobiology.
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ABSTRACT: This publication, by reviewing 1300 studies published on autism in 2008, represents an update on this topic. Results include possible parental influences, maternal conditions, and studies on genes and chromosomes. Possible etiological factors involve the “extreme male brain,” defects in the mirror neuron system, vaccines, underconnectivity, disorders of central coherence, and many other more specific etiologies. Assessments or tests for autism are also reviewed. Characteristics of autistic individuals include repetitive behavior, language disorders, sleep disturbances, social problems, joint attention disorders, seizures, allergic reactions, and various behavioral changes. Cognitive changes involve IQ, reasoning, and verbal and language disorders. The savant syndrome is a fascinating phenomenon, at times seen in autistic individuals. Neurophysiological and neuroanatomical changes are also reviewed, as are comorbid conditions. Finally, treatment involves various medications including risperidone, ziprasidone, and antipsychotic drugs, as well as different procedures such as magnetic stimulation, acupuncture, and hyperbaric oxygen therapy. As mentioned in the 2007 survey, nearly every conceivable problem that a child can have may be found in these unfortunate children and nearly every conceivable etiology has been mentioned to account for this serious disorder.Epilepsy & Behavior 12/2009; · 2.06 Impact Factor