Autism and Asperger’s Syndrome: A Cognitive Neuroscience Perspective

Leo Kanner, an Austrian born American psychiatrist first described autism in 1943 152. His observations of a small group of children with behavioral symptoms of social withdrawal, impaired language/communication and obsession with sameness led to recognition of autism as a specific pervasive developmental disorder. At about the same time Austrian psychiatrist Hans Asperger independently described similar symptoms in a small group of children except that the " Asperger " children were high functioning with better language and cognitive skills than those described by Kanner 11. Both Kanner and Asperger used the word autistic to describe the pathology in the children they observed—a term rooted in the Greek " autos " (self) and coined by Swiss psychiatrist Eugen Bleuler to describe symptoms in his schizophrenic patients. Before Kanner and Asperger defined autism as a specific disorder, children with autistic symptoms were most likely classed and treated as mentally retarded or, if they were high functioning, perhaps as schizophrenic. The symptoms described by Kanner and Asperger remain the core diagnostic symptoms for autism and associated disorders. Autism Spectrum Disorders (ASD) as specified in the DSM-IV TR (a text revision of the DSM-IV) include autistic disorder (classic autism), Asperger's disorder, pervasive developmental disorder not otherwise specified, Rett's disorder, and childhood disintegrative disorder 8. This chapter is limited to discussion of autistic disorder and Asperger's disorder. Neuroanatomic Abnormalities. Studies of neuroanatomic abnormality in autism are generally inconsistent and often controversial. There has been a veritable explosion of the number of MRI anatomic studies in the last decade. The methods are quite variable, samples are usually small, and, with a few exceptions, there is little agreement overall. Some newer smoothing and normalization techniques used to process MRI data require, at the very least, the questionable assumption that ASD brains can be warped accurately to a standard normal template. Some studies make strong claims about small structures (e.g., the amygdala) when their image analysis has " smoothed " across an area that is similar in size to the structure of interest. That is, they very well may have included surrounding tissue in the measurement of the structure of interest. A few things are clear. There is widespread but heterogeneous brain structural abnormality in autism that can be seen on postmortem exam and MRI. Abnormalities are developmental in nature and most likely begin during prenatal or early post-natal brain development. The most common findings are summarized below, …