Asperger Syndrome Health Article

Definition

Asperger syndrome (AS), which is also called Asperger disorder or autistic psychopathy, belongs to a group of childhood disorders known as pervasive developmental disorders (PDDs) or autistic spectrum disorders. The syndrome was first described by Hans Asperger, an Austrian psychiatrist, in 1944. Asperger's work was unavailable in English before the mid-1970s; as a result, AS was often unrecognized in English-speaking countries until the late 1980s. Before the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV 1994), there was no official definition of AS.

Description

Children with AS learn to talk at the usual age and often have above-average verbal skills. They have normal or above-normal intelligence, and the ability to take care of themselves. The distinguishing features of AS are problems with social interaction, particularly reciprocating and empathizing with the feelings of others; difficulties with nonverbal communication (e.g., facial expressions); peculiar speech habits that include repeated words or phrases and a flat, emotionless vocal tone; an apparent lack of "common sense"; a fascination with obscure or limited subjects (e.g., doorknobs, railroad schedules, astronomical data, etc.), often to the exclusion of other interests; clumsy and awkward physical movements; and odd or eccentric behaviors (hand wringing or finger flapping; swaying or other repetitious whole-body movements; watching spinning objects for long periods of time).

Although less is known about adults with Asperger syndrome, they are often described as having rigid interests, social insensitivity, and a limited capacity for empathizing with others. However, many adults with Asperger have normal or even superior intelligence and can make great intellectual contributions due to their increased ability to focus and block out outside distractions. Many individuals are highly creative and excel in areas such as music, mathematics, and computer sciences. They tend to excel in fields that require little social interaction.

Genetic profile

There is some indication that AS runs in families, particularly in families with histories of depression and bipolar disorder. Dr. Asperger noted that his initial group of patients had fathers with AS symptoms. In addition, many reports now document the presence of Asperger-like behaviors in the extended families of individuals affected with Asperger syndrome. The presence of these behaviors contributes to the theory that Asperger syndrome is one end of a spectrum of defects that encompasses Asperger syndrome, autism, and pervasive developmental delay (NOS).

As of 2005, no single gene has been found to cause Asperger syndrome. Several genetic studies have identified genes or chromosomal regions that may be involved in Asperger syndrome, but it has become clear that there is more than one gene involved in the development of this complex syndrome. As of 2005, there are several candidate regions or areas of chromosomes involved in the development of this complex syndrome. These regions include the long arm of chromosome 1 (1q21-q22), the long arm of chromosome 3 (3q25-q27), the long arm of the X chromosome (Xq13), and the short arm of the X chromosome (Xp22.33). Further studies will need to be done to determine if any of these regions contains genes that contribute to the development of Asperger syndrome.

Demographics

Although the incidence of AS has been variously estimated between 0.024% and 0.36% of the general population in North America and northern Europe, further research is required to determine its true rate of occurrence—especially because the diagnostic criteria have been defined so recently. Previous research suggested that the overall rate of pervasive developmental disorders (PDDs) is 30 out of 10,000 people, but more recent research from 2003 revealed that the incidence of PDD may be as high as 60 out of 10,000. The exact rate for Asperger syndrome has not been established, but it is thought to be approximately 2.5 out of 10,000.

It is unclear whether the rate of PDDs is actually increasing or if the increase that has been seen is due to wider diagnostic criteria and an increasing awareness of the diagnosis, leading to more individuals receiving the correct diagnosis. More research is necessary to answer this question completely.

AS appears to be much more common in boys. One Swedish study found the male/female ratio to be 4:1. Dr. Asperger's first patients were all boys, but girls have been diagnosed with AS since the 1980s. Asperger syndrome appears to affect all races equally.

Signs and symptoms

About 50% of patients with Asperger syndrome has a history of oxygen deprivation during the birth process, which has led to the hypothesis that the syndrome is caused by damage to brain tissue before or during childbirth. Another cause that has been suggested is an organic defect in the functioning of the brain. There are behavioral symptoms that are considered diagnostically significant.