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.
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.
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.
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.
As of 2005, there are no blood tests or brain scans that can be used to diagnose AS. Until DSM-IV (1994), there was no official list of symptoms for the disorder, which made its diagnosis both difficult and inexact. Although most children with AS are diagnosed between five and nine years of age, many are not diagnosed until adulthood. Misdiagnoses are common; AS has been confused with such other neurological disorders as Tourette syndrome , or with attention-deficit disorder (ADD), oppositional defiant disorder (ODD), or obsessive-compulsive disorder (OCD). Some researchers think that AS overlaps with some types of learning disability, such as the nonverbal learning disability (NLD) syndrome identified in 1989. As of 2005, there is no clear answer to the question of whether AS is a distinct syndrome or a subtype of autism.
The inclusion of A syndrome as a separate diagnostic category in DSM-IV was justified on the basis of a large international field trial of more than 1,000 children and adolescents. Nevertheless, the diagnosis of AS is also complicated by confusion with such other diagnostic categories, such as high-functioning (IQ >70) autism (HFA) and schizoid personality disorder of childhood. With regard to schizoid personality disorder, Asperger syndrome does not have an unchanging set of personality traits, but has a developmental dimension. AS is distinguished from HFA by the following characteristics:
- later onset of symptoms (usually around three years of age)
- early development of grammatical speech (the AS child's verbal IQ is usually higher than performance IQ—the reverse being the case in autistic children)
- less severe deficiencies in social and communication skills
- presence of intense interest in one or two topics
- physical clumsiness and lack of coordination
- family is more likely to have a history of the disorder
- lower frequency of neurological disorders
- more positive outcome in later life
DSM-IV criteria for Asperger syndrome
DSM-IV specifies six diagnostic criteria for AS:
- The child's social interactions are impaired in at least two of the following ways: markedly limited use of nonverbal communication; lack of age-appropriate peer relationships; failure to share enjoyment, interests, or accomplishment with others; lack of reciprocity in social interactions.
- The child's behavior, interests, and activities are characterized by repetitive or rigid patterns, such as an abnormal preoccupation with one or two topics, or with parts of objects; repetitive physical movements; or rigid insistence on certain routines and rituals.
- The affected individual's social, occupational, or educational functioning is significantly impaired.
- The child has normal age-appropriate language skills.
- The child has normal age-appropriate cognitive skills, self-help abilities, and curiosity about the environment.
- The child does not meet criteria for another specific PDD or schizophrenia.
Other diagnostic scales and checklists
Other instruments that have been used to identify children with AS include Gillberg's criteria, a six-item list compiled by a Swedish researcher that specifies problems in social interaction, a preoccupying narrow interest, forcing routines and interests on the self or others, speech and language problems, nonverbal communication problems, and physical clumsiness; and the Australian Scale for Asperger Syndrome (ASAS), a detailed multi-item questionnaire developed in 1996.
Brain imaging findings
As of 2005, only a few structural abnormalities of the brain have been linked to AS. Findings include abnormally large folds in the brain tissue in the left frontal region, abnormally small folds in the operculum (a lid-like structure composed of portions of three adjoining brain lobes), and damage to the left temporal lobe. The first brain imaging study (using single-photon emission tomography [SPECT]) of patients with AS found a lower-than-normal blood supply in the left parietal area of the brain. Brain imaging studies on a larger sample of patients is the next stage of research.
Treatment and management
As of 2005, there is no cure for AS and no prescribed regimen for affected patients. Specific treatments are based on the individual's symptom pattern.
The drugs that are recommended most often for children with AS include psychostimulants (methylphenidate, pemoline), clonidine, or one of the tricyclic antidepressants (TCAs) for hyperactivity or inattention; beta blockers, neuroleptics, or lithium for anger or aggression; selective serotonin reuptake inhibitors (SSRIs) or TCAs for rituals and preoccupations; and SSRIs or TCAs for anxiety symptoms. One alternative herbal remedy that has been tried with AS patients is St. John's Wort.
Individuals with Asperger syndrome often benefit from psychotherapy, particularly during adolescence, in order to cope with depression and other painful feelings related to their social difficulties.
Most patients with AS have normal or above-normal intelligence, and are able to complete their education up through the graduate or professional school level. Many are unusually skilled in music or good in subjects requiring rote memorization. On the other hand, the verbal skills of children with AS frequently cause difficulties with teachers, who may not understand why these "bright" children have social and communication problems. Some children with AS are dyslexic; others have difficulty with writing or mathematics. In some cases, these children have been mistakenly put in special programs either for children with much lower levels of functioning, or for children with conduct disorders. Children with AS do best in structured learning situations in which they learn problem-solving and life skills, as well as academic subjects. They frequently need protection from the teasing and bullying of other children, and often become hypersensitive to criticism by their teen years.
Adults with AS are productively employed in a wide variety of fields. They do best, however, in jobs with regular routines or jobs that allow them to work in isolation. Employers and colleagues may need some information about Asperger syndrome in order to understand the employee's behavior.
AS is a lifelong but stable condition. The prognosis for children with AS is generally good as far as intellectual development is concerned, although few school districts as of 2005 are equipped to meet their special social needs; however, awareness of this unique disorder is growing. There is some research to suggest that people with AS have an increased risk of becoming psychotic in adolescence or adult life. Adult individuals with AS can make significant contributions to society and some marry and do well in their careers despite the social handicaps of their condition. In fact, there is a contingent of adults with AS who argue that AS is not a handicap or condition to be cured. They feel that their "differences" should be appreciated in a more positive light. However, some adults with AS live very socially isolated existences. While individuals with AS can be taught specific social guidelines, the underlying social impairment is lifelong.
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th edition. Washington, DC: American Psychiatric Association, 1994.
Ozonoff, Sally. A Parent's Guide to Asperger Syndrome and High-Functioning Autism: How to Meet the Challenges and Help Your Child Thrive. 1st Edition. New York, NY: The Guilford Press, 2002.
Romanowski Bashe, Patricia, and Barbara Kirby. The OASIS Guide to Asperger Syndrome: Advice, Support, Insight, and Inspiration. 1st Edition. New York, NY: Crown Publishing, 2001.
Thoene, Jess G., editor. Physicians' Guide to Rare Diseases. Montvale, NJ: Dowden Publishing Company, 1995.
Autism Research Institute. 4182 Adams Ave., San Diego, 92116. Fax: (619) 563-6840.
Families of Adults Afflicted with Asperger's Syndrome (FAAAS). PO Box 514, Centerville, MA 02632. (April 8, 2005.) <http://www.faaas.org>.
National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. (203) 746-6518 or (800) 999-6673. Fax: (203) 746-6481. (April 8, 2005.) <http://www.rarediseases.org>.
Autism and Asperger's Syndrome. (April 8, 2005.) <http://www.aspergerssyndrome.org/>.
Center for the Study of Autism Home Page. (April8, 2005.) <http://www.autism.org//asperger.html>.
MAAP Services for Autism and Asperger Spectrum. (April 8, 2005.) <http://maapservices.org>.
O.A.S.I.S. (Online Asperger Syndrome Information and Support). (April 8, 2005.) <http://www.udel.edu/bkirby/asperger/>.
Rebecca J. Frey, PhD
Kathleen A. Fergus, MS, CGC