Definition Autism and Aspergers are developmental disorders on a larger spectrum called Autism Spectrum Disorders (ASDs). Autism – usually have significant language delays, social and communication challenges, unusual behaviors and interests; may have intellectual disability Aspergers – may have social challenges and unusual behaviors and interests; typically do not have language problems or intellectual disability http://www.cdc.gov/NCBDDD/autism/videos/whatisautism. html - this is a link to a short video that explains the signs and symptoms related to ASDs.Source: (Center for Disease Control, 2012)
General Information 1 in 88 children have been identified with an autism spectrum disorder Typically diagnosed between the ages of 2 and 4 Because of the late diagnosis, brain development in autism is largely unstudied during the first 2 years of life – the “crucial period”Source: (Center for Disease Control, 2012)
Head Circumference Typically normal average at birth – 25th %ile By 6-14 months, head circumference is at 84th %ile; growth slows down at end of 2nd year Brain volume of autistic 3-4 years old about 10% larger than normal (1.5 cm) Cerebrum, cerebellum, and amygdala also larger than normalSource: (Courchesne, 2004)
Source: (University of California, San Diego, 2003)
Gray Matter & White Matter In2-4 year olds, brain enlargement was found to be due to significant increases in cerebral white matter (18%), cerebral gray matter (12%), cerebellar white matter (39%), but not cerebellar gray matter. Grey matter volume reaches a peak between ages 4 & 6, then decreases constantly White matter volume increase in the first decade of life and stays relatively stableSources: (Courchesne 2004) (Predescu, et. al. 2010
Brain dysfunction in autism is correlated with abnormal patterns of development affecting the whole brain as well as circuits involving the prefrontal cortex, the limbic system, and cerebellum. The amygdala and hippocampus increase in size through adolescence.Picture Source: (Health on Care) Source: Predescu et. al. 2010)
Affected Parts of the Brain The most consistent changes were in the amygdala, hippocampus, and functionally related entorhinal cortex and mammillary body. Using SPECT techniques, researchers reported that blood flow is significantly reduced in the left temporal region in high-functioning autism, while a more recent study reported a correlation between reduced temporal lobe blood flow and the severity of the disorder.Source: (Lathe, 2006)
Boys vs. Girls Girls with autism showed substantial reduction in cerebellar gray matter volumes as compared to normal girls as well as to boys with autism Brain development abnormalities appear to be more severe in girls than in boys with autism Every structural volume abnormality present in boys with autism was also present in girls with autismSource: (Courchesne, 2004)
Reference List Center for Disease Control. (29, March 2012). Data and statistics. Retrieved from http://www.cdc.gov/ncbddd/autism/data.html/This site gave statistical information and data related to Autism. It also talks aboutdiagnosis and economic costs of autism. A basic chart with data about theprevalence of ASDs was extracted from this site. Center for Disease Control. (29, March 2012). Facts about asds. Retrieved from http://www.cdc.gov/ncbddd/autism/facts.htmlThis website gave general information about Autism Spectrum Disorders. Itdiscusses the different types of ASDs, signs and symptoms, treatments, and riskfactors, among other information. Courchesne, E. (2004). Brain development in autism: Early overgrowth followed by premature arrest of growth. Mental Retardation & Developmental Disabilities Research Reviews, 10(2), 106-111.*This article discusses brain development and growth in autism. Circumference ofthe head, rate of growth, growth at different ages, and regional differences areall discussed.
References Cont’d Courchesne, E., K. Pierce, C. M. Schumann, E. Redcay, J. A. Buckwalter, D. P. Kennedy, and J. Morgan. "Mapping Early Brain Development in Autism." Neuron. 56.2 (2007): 399-413. Web. 13 Aug. 2012.*This article talks about findings during the first few years of life and argues thatearly brain overgrowth is a key factor in the onset of autism. The article alsoincludes graphs that map out data related to overgrowth in the brain. Health on Care. (n.d.). Autism – causes, symptoms and treatment. Retrieved from http://www.healthoncare.com/autism-causes-symptoms-and- treatment.htmlThis website gave a brief overview of what autism is and the causes andsymptoms of autism. The site has a picture of the brain that shows which parts ofthe brain which are affected by autism. This photo was extracted for mypresentation.
References Cont’d Lathe, Richard. Autism, Brain and Environment. London: Jessica Kingsley Publishers, 2006.*This is a book about autism that discusses how autism affects the brain and theabnormalities and dysfunction associated with the disorder. The book also discusses howthe environment has an effect on the onset of autism. Predescu, E., Sipos, P., Sipos, R., Iftene, F., & Balázsi, R. (2010). BRAIN VOLUMES IN AUTISM AND DEVELOPMENTAL DELAY -- A MRI STUDY. Journal Of Cognitive & Behavioral Psychotherapies, 10(1), 25-38.This article compared children with ASD and children with developmental delay. Itcompared total brain volume of both sets of children as well as volume of gray matterand white matter between the groups of children. University of California, San Diego. (2003). Ucsd researchers find brain overgrowth during first year of life in autism. Retrieved from http://health.ucsd.edu/news/2003/07_15_courchesne.htmlThis website contained an article talking about brain growth in children with autismduring their first year of life. The website contained a photo comparing the size of anaverage brain with the size of a brain with autism. This photo was extracted for mypresentation.