Asperger Syndrome: General Information and Across the Lifespan
Introduction
Asperger syndrome (also called Asperger disorder) is a relatively new category of developmental disorder, the term having only come into more general use over the past fifteen years. Although a group of children with this clinical picture was originally and very accurately described in the 1940ís by a Viennese pediatrician, Hans Asperger, Asperger syndrome (AS) was "officially" recognized in the Diagnostic and Statistical Manual of Mental Disorders for the first time in the fourth edition published in 1994. Because there have been few comprehensive review articles in the medical literature to date, and because AS is probably considerably more common than previously realized, this discussion will endeavor to describe the syndrome in some detail and to offer suggestions regarding management. Students with AS are not uncommonly seen in mainstream educational settings, although often undiagnosed or misdiagnosed, so this is a topic of some importance for educational personnel, as well as for parents.
Asperger syndrome is the term applied to the mildest and highest functioning end of what is known as the spectrum of pervasive developmental disorders (or the Autism spectrum). Like other conditions along that spectrum it is felt to represent a neurologically-based disorder of development, most often of unknown cause, in which there are deviations or abnormalities in three broad aspects of development: social relatedness and social skills, the use of language for communicative purposes, and certain behavioral and stylistic characteristics involving repetitive or perseverative features and a limited but intense range of interests. It is the presence of these three categories of dysfunction, which can range from relatively mild to severe, which clinically defines all of the pervasive developmental disorders, from AS through to classic Autism. Although the idea of a continuum of PDD along a single dimension is helpful for understanding the clinical similarities of conditions along the spectrum, it is not at all clear that Asperger syndrome is just a milder form of Autism or that the conditions are linked by anything more than their broad clinical similarities. Asperger syndrome represents that portion of the PDD continuum which is characterized by higher cognitive abilities (at least normal IQ by definition, and sometimes ranging up into the very superior range) and by more normal language function compared to other disorders along the spectrum. In fact, the presence of normal basic language skills is now felt to be one of the criteria for the diagnosis of AS, although there are nearly always more subtle difficulties with pragmatic/social language. Many researchers feel it is these two areas of relative strength that distinguish AS from other forms of Autism and PDD and account for the better prognosis in AS. Developmentalists have not reached consensus as to whether there is any difference between AS and what is termed High Functioning Autism (HFA). Some researchers have suggested that the basic neuropsychological deficit is different for the two conditions, but others have been unconvinced that any meaningful distinction can be made between them. One researcher, Uta Frith, has characterized children with AS as having "a dash of Autism." In fact, it is likely that there may be multiple underlying subtypes and mechanisms behind the broad clinical picture of AS. This leaves room for some confusion regarding diagnostic terms, and it is likely that quite similar children across the country have been diagnosed with AS, HFA, or PDD, depending upon by whom or where they are evaluated.
Since AS itself shows a range or spectrum of symptom severity, many less impaired children who might meet criteria for that diagnosis receive no diagnosis at all and are viewed as "unusual" or "just different," or are misdiagnosed with conditions such as Attention Deficit Disorder, emotional disturbance, etc. Many in the field believe that there is no clear boundary separating AS from children who are "normal but different." The inclusion of AS as a separate category in the new DSM-4, with fairly clear criteria for diagnosis, should promote greater consistency of labeling in the future.
Epidemiology
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The best studies that have been carried out to date suggest that AS is considerably more common than "classic" Autism. Whereas Autism has traditionally been felt to occur in about 4 out of every 10,000 children, estimates of Asperger syndrome have ranged as high as 20-25 per 10,000. That means that for each case of more typical Autism, schools can expect to encounter several children with a picture of AS (that is even more true for the mainstream setting, where most children with AS will be found). In fact, a careful, population-based epidemiological study carried out by Gillberg's group in Sweden, concluded that nearly 0.7% of the children studied had a clinical picture either diagnostic of or suggestive of AS to some degree. Particularly if one includes those children who have many of the features of AS and seem to be milder presentations along the spectrum as it shades into "normal," it seems not to be a rare condition. All studies have agreed that Asperger syndrome is much more common in boys than in girls. The reasons for this are unknown. AS is fairly commonly associated with other types of diagnoses, again for unknown reasons, including: tic disorders such as Tourette disorder, attentional problems, and mood problems such as depression and anxiety. In some cases there is a clear genetic component, with one parent (most often the father), showing either the full picture of AS or at least some of the traits associated with AS; genetic factors seem to be more common in AS compared to more classic Autism. Temperamental traits such as having intense and limited interests, compulsive or rigid style, and social awkwardness or timidity also seem to be more common, alone or in combination, in relatives of AS children. Sometimes there will be a positive family history of Autism in relatives, strengthening the impression that AS and Autism are sometimes related conditions. Other studies have demonstrated a fairly high rate of depression, both bipolar and unipolar, in relatives of children with AS, suggesting a genetic link in at least some cases. It seems likely that for AS, as for Autism, the clinical picture we see is probably influenced by many factors, including genetic ones, so that there is no single identifiable cause in most cases. |
Definition
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The new DSM-4 criteria for a diagnosis of AS, with much of the language carrying over from the diagnostic criteria for Autism, include the presence of:
These behaviors must be sufficient to interfere significantly with social or other areas of functioning. Furthermore, there must be no significant associated delay in either general cognitive function, self-help/adaptive skills, interest in the environment, or overall language development. Christopher Gillberg, a Swedish physician who has studied AS extensively, has proposed six criteria for the diagnosis, elaborating upon the criteria set forth in DSM-4. His six criteria capture the unique style of these children, and include:
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Clinical Features
Reprinted with the permission of MAAP Service, Inc. © 2008 MAAP Service, Inc.
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