Asperger Syndrome

Updated: Mar 26, 2014
  • Author: James Robert Brasic, MD, MPH; Chief Editor: Caroly Pataki, MD  more...
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Overview

Practice Essentials

Asperger syndrome is a term applied to a condition characterized by persistent impairment in social interactions and by repetitive behavior patterns and restricted interests. Once generally regarded as a discrete disorder, it is categorized as a form of autism spectrum disorder (ASD) in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). [1]

Signs and symptoms

In DSM-5, ASD encompasses the following 4 previously separate diagnoses [1] :

  • Autism
  • Asperger disorder
  • Childhood disintegrative disorder
  • Pervasive developmental disorder not otherwise specified

These are now considered forms of a single disorder characterized by different levels of severity in the following 2 core symptom areas, both of which are required for a diagnosis of ASD:

  • Impairments in social communication and social interaction
  • Restricted, repetitive patterns of behavior, interests, or activities

Individual clinical characteristics are denoted through the use of specifiers, as follows:

  • With or without accompanying intellectual impairment
  • With or without accompanying language impairment
  • Associated with a known medical or genetic condition or environmental factor
  • Associated with another neurodevelopmental, mental, or behavioral disorder
  • With catatonia [2, 3, 4]

By the current DSM-5 criteria, individuals previously diagnosed with Asperger syndrome would be diagnosed as having ASD without language or intellectual impairment.

The history is likely to elicit the following:

  • Social problems
  • Communication abnormalities
  • Speech and hearing abnormalities
  • Sensory sensitivity

Typical physical findings in children with Asperger syndrome may include the following:

  • Lax joints (eg, an immature or unusual grasp for handwriting and other fine hand movements)
  • Clumsiness
  • Anomalies of locomotion, balance, manual dexterity, handwriting, rapid movements, rhythm, and imitation of movements
  • Impaired ball-playing skills

Screening for a theory of mind can help identify some of the core behavioral symptoms of Asperger syndrome. Such screening has the following 2 main components:

  • Doll-play paradigm
  • Imagination task

See Presentation for more detail.

Diagnosis

Neuropsychological testing should focus on simple and complex problem-solving tasks, using tests and scales such as the following:

  • Wisconsin Card Sorting Test
  • Trail-Making Test
  • Stanford-Binet Scale

The Autism Screening Checklist (see the image below) is helpful in identifying children with characteristics of autism spectrum disorder (ASD) and in differentiating children with these disorders from children with schizophrenia and other psychoses.

Autism screening checklist. Autism screening checklist.

Magnetic resonance imaging (MRI) is not required for diagnosing Asperger syndrome but may demonstrate the following:

  • Hypoplasia of the inferior precentral gyrus and the anterior portion of the superior temporal gyrus, resulting in a widening of the sylvian fissure and a partial exposure of the insular cortex
  • Hypoplasia of the right temporo-occipital cortex
  • Small gyri of the posterior parietal lobes
  • Enlargement of the right lateral ventricle
  • Diminished size of the midbrain and medulla oblongata

Other tests that, though not required for diagnosis, may add useful information are as follows:

  • Event-related brain potential testing via electroencephalography (EEG)
  • Computed tomography (CT) of the head

Genetic tests that may be useful include the following:

  • Chromosomal microarray (CMA), or array comparative genomic hybridization (aCGH)
  • Karyotyping
  • Fragile X (FMR1 molecular studies)
  • Methylation studies
  • Methyl-CpG-binding protein (MECP2) analysis [5]
  • Phosphatase and tensin (PTEN) homolog testing [6]
  • Specific gene sequencing when a particular syndrome is suspected

See Workup for more detail.

Management

Treatment of people with Asperger syndrome consists primarily of instruction and counseling, focusing on the following areas:

  • Reinforcement of appropriate social behaviors
  • Implementation of communication and language strategies
  • Development of social skills
  • Relaxation therapy
  • Encouragement of special skills (eg, music or mathematics)
  • Career counseling and orientation

In addition, any comorbid conditions should be managed as appropriate, including the following:

  • Depression
  • Behavioral disorders

Drugs to treat the core characteristics of Asperger syndrome have not yet been identified. Pharmacologic interventions are used to treat comorbid disorders but should not be prescribed in the absence of an indication. Vigilance for drug toxicity must be maintained.

See Treatment for more detail.

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Background

Asperger syndrome (also referred to as Asperger disorder) is a term applied to a form of autism spectrum disorder (ASD) [7] characterized by persistent impairment in social interactions and by repetitive behavior patterns and restricted interests. Although in the past this syndrome was commonly considered a separate diagnosis, it is now subsumed under the diagnosis of ASD in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). [1]

Asperger syndrome is generally evident in children older than age 3 years and occurs most often in males. (See Etiology and Epidemiology.) Children with this syndrome typically exhibit a limited capacity for spontaneous social interactions, a failure to develop friendships, and a limited number of intense and highly focused interests.

People with Asperger syndrome may have certain communication problems, including poor nonverbal communication and pedantic speech, but many of them have good cognitive and verbal skills. Physical symptoms may include early childhood motor delays, clumsiness, fine motor difficulty, gait anomalies, and odd movements. (See Presentation.)

Standard early childhood development surveillance can identify some children who should receive further testing for Asperger syndrome. An ASD-specific tool should be used at 18 and 24 months. [8] In children with possible developmental issues, screening for a theory of mind (ie, determining whether these children have the ability to impute mental states to themselves and others) is an important process a clinician can use to identify some of the core behavioral symptoms of Asperger syndrome. (See Presentation.)

Individuals with Asperger syndrome have normal, or even superior, intelligence while demonstrating social insensitivity or even apparent indifference toward loved ones. Indeed, individuals with Asperger syndrome have accomplished cutting-edge research in computer science, mathematics, and physics, as well as outstanding creative work in art, film, and music. Many prominent individuals (eg, Albert Einstein) have demonstrated traits suggesting Asperger syndrome.

Additionally, some individuals with Asperger syndrome devote sustained daily concentration to the development of musical, mathematical, and other skills. This may facilitate the refinement of highly specialized tasks that would be beyond reach for many people without the syndrome.

Neuropsychological testing and event potential studies can be used to uncover characteristics of Asperger syndrome. Magnetic resonance imaging (MRI) and positron emission tomography (PET) can reveal brain anomalies associated with the condition. (See Workup.) None of these studies are required for diagnosis, but the results can help guide treatment planning.

If Asperger syndrome is diagnosed, social skills training and other psychological interventions may be provided. Although the deficits manifested by people with Asperger syndrome are often debilitating, many of these individuals experience positive outcomes, especially those who excel in areas not dependent on social interaction. (See Treatment.)

Since some people with Asperger syndrome exhibit acute awareness of environments and highly developed adaptive skills, they may escape detection in childhood. Thus, children, adolescents, and adults with Asperger syndrome may never be recognized as having Asperger syndrome. In particular, the ability of women with Asperger syndrome to conform with behavioral expectations of women may result in their integration into society without awareness of their condition. Thus, the reported male predominance in populations of people with Asperger disorder may reflect a high threshold to detect the condition in women. The stress of environmental changes and life events may cause adolescents and adults to seek diagnosis. An unknown number of adults with Asperger syndrome may be undiagnosed for their entire lives. There may exist many individuals with Asperger syndrome who are unaware of their condition.

Diagnostic criteria (DSM-5)

In DSM-5, the diagnosis of ASD encompasses the following 4 previously separate diagnoses [1] :

  • Autism
  • Asperger disorder
  • Childhood disintegrative disorder
  • Pervasive developmental disorder not otherwise specified

This change in nosology reflects a scientific consensus that these are not separate disorders but, rather, forms of a single disorder characterized by different levels of severity with respect to the following 2 core symptom areas, both of which are required for a diagnosis of ASD:

  • Impairments in social communication and social interaction
  • Restricted, repetitive patterns of behavior, interests, or activities

These symptoms are present from early childhood and limit or impair everyday functioning.

Individual clinical characteristics are denoted through the use of specifiers, as follows:

  • With or without accompanying intellectual impairment
  • With or without accompanying language impairment
  • Associated with a known medical or genetic condition or environmental factor
  • Associated with another neurodevelopmental, mental, or behavioral disorder
  • With catatonia [2, 3, 4]

By the current DSM-5 criteria, individuals previously diagnosed with Asperger syndrome would be diagnosed as having ASD without language or intellectual impairment.

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Pathophysiology

In Asperger syndrome, the clinical manifestations presumably reflect alterations in brain development resulting from interactions between multiple genes, epigenetic factors affecting gene expression, and exposure to environmental factors. [9] Gaigg and Bowler hypothesized that impairments in the connections between the amygdala and associated structures of the brain may play a role in the pathogenesis of Asperger symptoms. [10]

People with Asperger syndrome demonstrate problems analyzing configurations. These deficits probably contribute to these individuals’ difficulty with facial recognition. [11] Bowler et al reported that people with Asperger syndrome have fewer memories than healthy control subjects do. [12]

Dyslipidemia may play a role in Asperger syndrome as well. Dziobek et al reported elevations of total cholesterol and low-density lipoprotein in people with Asperger syndrome. [13]

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Etiology

The etiology of Asperger syndrome is unknown. Some individuals with the syndrome have a history of complications in the prenatal and neonatal periods and during delivery, [14, 15, 16, 17, 18] but the relationship between obstetric complications and Asperger syndrome is unclear. [15, 16]

Unfavorable experiences in the prenatal, perinatal, and postnatal periods may increase the likelihood of Asperger syndrome. [14, 15, 16, 19, 20, 17, 18] In a Swedish study, adverse perinatal events were recorded for about two thirds of 100 males with Asperger syndrome, and the mothers experienced infection, vaginal hemorrhage, preeclampsia, and other adverse events during pregnancy at an above-average rate. [18] Whether the syndrome is a consequence or a cause of perinatal complications in such cases is unknown.

Genetic factors

Reports of families with multiple members meeting the criteria for Asperger syndrome suggest a genetic contribution to development of the disorder. The past few years have seen a flood of research and insight into the underlying genetic contribution to Asperger syndrome, as well as to other forms of ASD. Hundreds of candidate genes and copy number variation (CNV) loci have been associated with ASD (see Genetics of Autism Spectrum Disorders).

The neurobiology and genetics are complicated. [21, 22] Genes involving the neuronal synaptic pathways are under particular investigation. Whereas most genome-wide association studies (GWAS) look at the entire range of ASD, some chromosomal regions have been associated specifically with Asperger syndrome, including 5q21.1, 3p14.2, 3q25, and 3p23. [23]

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Epidemiology

Because of the divergent diagnostic criteria used, estimates of the prevalence of Asperger syndrome vary widely. [24] In various studies from the United States and Canada, for example, reported rates have ranged from 1 case in 250 children to 1 case in 10,000. Additional epidemiologic studies are needed, using widely accepted criteria and a screening instrument that targets these criteria.

A population study in Sweden estimated the prevalence of Asperger syndrome as 1 case in 300 children. [25] This estimate is convincing for Sweden because complete medical records are available for all citizens in that country and the population is highly homogeneous. However, in other parts of the world, where neither of these factors may apply, prevalence may be quite different.

Like Sweden, other Scandinavian countries keep complete medical records for their populations and thus are uniquely suitable locations for conducting pristine epidemiologic studies. Comparable studies cannot always be readily carried out in other parts of the world. For example, in New York City, many inhabitants are immigrants, and it is not always possible to obtain health records from their country of origin.

To extrapolate from the Swedish study, Asperger syndrome may be more common than clinicians once thought. Pediatricians, family physicians, general practitioners, and other health professionals in North America may underdiagnose this disorder. Family members and friends may have a tendency to ascribe the signs of Asperger syndrome to individual idiosyncrasies.

Asperger syndrome has no apparent racial predilection. The estimated male-to-female ratio is approximately 4:1. The syndrome is commonly diagnosed in the early school years and less frequently identified during early childhood or in adulthood. However, there may exist an unknown number of adults with excellent awareness and adaptation skills who are never diagnosed during their lifetimes. There may be a cohort of women with Asperger syndrome who conform with the behavioral expectations of society and are never diagnosed.

Prognosis

People with Asperger syndrome tend to have a better prognosis when they receive support from family members who are knowledgeable about the disorder. These individuals may be taught specific social guidelines, but the underlying social impairment is believed to be lifelong.

Individuals with Asperger syndrome appear to have a normal lifespan; however, they seem to endure an increased prevalence of comorbid psychiatric maladies (eg, depression, mood disorders, obsessive-compulsive disorder [OCD], and Tourette disorder). Comorbid psychiatric disorders, when present, significantly affect the prognosis.

Depression and hypomania are especially common among adolescents and adults with Asperger syndrome, particularly those with a family history of these conditions. (Caregivers of persons with Asperger syndrome may be prone to depression as well.)

An increased risk of suicide is observed in persons with this syndrome, with risks possibly rising in proportion to the number and severity of comorbid maladies. Asperger syndrome is probably undiagnosed in many suicide cases, both because the level of awareness of the condition is often low and because the tools used to identify it are often ineffective and unreliable. Consequently, people with Asperger syndrome who commit suicide are frequently reported as having other or undiagnosed psychiatric problems.

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Patient Education

Individuals with Asperger syndrome and related conditions—as well as their families, teachers, and communities—can benefit from the experiences of other individuals with this disorder and from the experiences of their advocates. The following organizations provide information and advice to persons with Asperger syndrome and related conditions:

  • ASPEN (Asperger Syndrome Education Network, Inc), 9 Aspen Circle, Edison, NJ 08820; 732-321-0880; info@aspennj.org
  • Asperger Norfolk, Old Lion Cottage, Thurne, Great Yarmouth NR29 3AP, United Kingdom; +44 01 692 670 864
  • Jessica Kingsley Publishers, 400 Market Street, Suite 400, Philadelphia, PA 19106; 866-416-1078 (toll-free ordering), 215-922-1161 (main), 215-922-1474 (fax); orders@jkp.com; 116 Pentonville Road, London N1 9JB, United Kingdom; +44 (0)20 7833 2307 (main), +44 (0)20 7837 2917 (fax); post@jkp.com

The organizations above may also be contacted for information about assessment and treatment facilities located near the patient. People with Asperger syndrome and their families benefit from intensive assessments and treatment interventions.

Several other resources have been recorded in a manual entitled A Parent’s Guide to Asperger Syndrome and High-Functioning Autism: How to Meet the Challenges and Help Your Child Thrive. [26] This excellent guide for lay people who encounter people with Asperger syndrome provides practical suggestions for day-to-day life.

People with developmental disabilities, including those with Asperger syndrome, are vulnerable to sexual abuse, and the most severely disabled are at the greatest risk. For this reason, parents and caregivers must be alert to avoid situations inviting sexual abuse. Additionally, children with Asperger syndrome must be trained to recognize impending sexual abuse and to develop plans of action for preventing it. [27]

For patient education information, see the Brain and Nervous System Center, as well as Asperger Syndrome.

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