By AMI KLIN, PH.D AND FRED R. VOLKMAR, M.D.

Asperger Syndrome (AS, also known as Asperger’s Disorder) is a severe developmental disorder characterized by major difficulties in social interaction, and restricted and unusual patterns of interest and behavior.

Autism is the most widely recognized pervasive developmental disorder (PDD). Other diagnostic concepts with features somewhat similar to autism have been less intensively studied, and their validity, apart from autism, is more controversial.

One of these conditions, termed Asperger syndrome (AS) was originally described by Hans Asperger, who provided an account of a number of cases whose clinical features resembled Kanner’s (1943) description of autism (e.g., problems with social interaction and communication, and circumscribed and idiosyncratic patterns of interest). However, Asperger’s description differed from Kanner’s in that speech was less commonly delayed, motor deficits were more common, the onset appeared to be somewhat later, and all the initial cases occurred only in boys. Asperger also suggested that similar problems could be observed in family members, particularly fathers.

This syndrome was essentially unknown in the English literature for many years. An influential review and series of case reports by Lorna Wing (1981) increased interest in the condition, and since then both the usage of the term in clinical practice and number of case reports and research studies have been steadily increasing. The commonly described clinical features of the syndrome include:

1. paucity of empathy;
2. naive, inappropriate, one-sided social interaction, little ability to form friendships and consequent social isolation;
3. pedantic and monotonic speech;
4. poor nonverbal communication;
5. intense absorption in circumscribed topics such as the weather, facts about TV stations, railway tables or maps, which are learned in rote fashion and reflect poor understanding, conveying the impression of eccentricity; and
6. clumsy and ill-coordinated movements and odd posture.

Although Asperger originally reported the condition only in boys, reports of girls with the syndrome have now appeared. Nevertheless, boys are significantly more likely to be affected. Although most children with the condition function in the normal range of intelligence, some have been reported to be mildly retarded. The apparent onset of the condition, or at least its recognition, is probably somewhat later than autism; this may reflect the more preserved language and cognitive abilities. It tends to be highly stable, and the higher intellectual skills observed suggest a better long-term outcome than is typically observed in autism.

Higher Functioning Autism or Asperger’s?

There are many similarities with autism without mental retardation (or “Higher Functioning Autism”), and the issue of whether Asperger syndrome and Higher Functioning Autism are different conditions is not resolved.

To some extent, the answer to this question depends on the way clinicians and researcher make use of this diagnostic concept, since until recently there was no “official” definition of Asperger syndrome. The lack of a consensual definition led to a great deal of confusion as researchers could not interpret other researchers’ findings, clinicians felt free to use the label based on their own interpretations or misinterpretations of what Asperger syndrome “really” meant, and parents were often faced with a diagnosis that nobody appeared to understand very well, and worse still, nobody appeared to know what to do about it.

School districts are often not aware of the condition, insurance carriers could not reimburse services provided on the basis of this “unofficial” diagnosis, and there was no published information providing parents and clinicians alike with guidelines on the meaning and implications of Asperger syndrome, including what should the diagnostic evaluation consist of and what forms of treatment and interventions were warranted.

Asperger’s Ascent to an Official Diagnosis

This situation has changed somewhat since Asperger syndrome was made “official” in DSM-IV (APA, 1994), following a large international field trial involving over a thousand children and adolescents with autism and related disorders (Volkmar et al., 1994). The field trials revealed some evidence justifying the inclusion of Asperger syndrome as a diagnostic category different from autism, under the overarching class of Pervasive Developmental Disorders. More importantly, it established a consensual definition for the disorder which should serve as the frame of reference for all those using the diagnosis. However, the problems are far from over. Despite some new research leads, knowledge on Asperger syndrome is still very limited. For example, we don’t really know how common it is, or the male/female ratio, or to what extent there may be genetic links increasing the likelihood of finding similar conditions in family members.

Clearly, the work on Asperger syndrome, in regard to scientific research as well as in regard to service provision, is only beginning. Parents are urged to use a great deal of caution and to adopt a critical approach toward information given to them. Ultimately, the diagnostic label – any label, does not summarize a person, and there is a need to consider the individual’s strengths and weaknesses, and to provide individualized intervention that will meet those (adequately assessed and monitored) needs. That notwithstanding, we are left with the question of what is the nature of this puzzling social learning disability, how many people does it affect, and what can we do to help those affected by it. The following guidelines summarize some of the information currently available on those questions.

This article by Ami Klin, Ph.D., and Fred R. Volkmar, M.D., Yale Child Study Center, New Haven, Connecticut and was originally published by the Learning Disabilities Association of America, June 1995. To learn more about Asperger’s Syndrome and Autism, please visit the Yale Developmental Disabilities Clinic website.