Asperger syndrome is an autism
spectrum disorder, and people with it therefore show significant
difficulties in social interaction, along with restricted and repetitive
patterns of behavior and interests. It differs from other autism spectrum
disorders by its relative preservation of linguistic and cognitive
development. Although not required for diagnosis, physical clumsiness and
atypical use of language are frequently reported.
Asperger syndrome is also called Asperger's syndrome,Asperger (or Asperger's) disorder,
or just
Asperger's.It is named
after the Austrian pediatrician Hans Asperger who, in 1944, described children in
his practice who lacked nonverbal communication skills,
demonstrated limited empathy with
their peers, and were physically clumsy. Fifty years
later, it was standardized as a diagnosis, but questions about many aspects
remain. For
example, there is lingering doubt about whether it is distinct from high-functioning autism (HFA);
partly because
of this, its prevalence is not
firmly established. The exact cause
is unknown, although research supports the likelihood of a genetic basis; brain imaging techniques have not identified a
clear common pathology.
There is no single treatment, and the effectiveness of particular
interventions is supported by only limited data. Intervention is aimed at improving symptoms and function. The mainstay of
management is behavioral therapy, focusing on specific
deficits to address poor communication skills, obsessive or repetitive routines,
and physical clumsiness. Most
individuals improve over time, but difficulties with communication, social
adjustment and independent living continue into
adulthood. Some
researchers and people with Asperger's have advocated a shift in attitudes
toward the view that it is a difference, rather than a disability that must be
treated or cured.
Asperger syndrome (AS) is one of the autism
spectrum disorders (ASD) or pervasive developmental
disorders (PDD), which are a spectrum of psychological conditions that are
characterized by abnormalities of social interaction and communication that
pervade the individual's functioning, and by restricted and repetitive interests
and behavior. Like other psychological development disorders, ASD begins in
infancy or childhood, has a steady course without remission or relapse, and has
impairments that result from maturation-related changes in various systems of
the brain. ASD,
in turn, is a subset of the broader autism phenotype (BAP), which describes individuals who may
not have ASD but do have autistic-like traits, such as social
deficits. Of the other four
ASD forms, autism is the most similar to
AS in signs and likely causes but its diagnosis requires impaired communication
and allows delay in cognitive development; Rett syndrome and childhood disintegrative
disorder share several signs with autism but may have unrelated causes; and
pervasive developmental disorder not
otherwise specified (PDD-NOS) is diagnosed when the criteria for a more
specific disorder are unmet.
The extent of the overlap
between AS and high-functioning autism (HFA—autism unaccompanied by mental
retardation) is unclear.[8][14][3] The current
ASD classification is to some extent an artifact of how autism was
discovered, and may not
reflect the true nature of the spectrum. A panel session at
a 2008 diagnosis-related autism research planning conference noted problems with
the classification of AS as a distinct subgroup of ASD, and two of three
breakout groups recommended eliminating AS as a separate diagnosis in future
versions of the Diagnostic
and Statistical Manual of Mental Disorders and of the International
Statistical Classification of Diseases and Related Health Problems.
Asperger syndrome is also called Asperger's syndrome (AS),
Asperger (or Asperger's) disorder (AD), or just
Asperger's.There is
little consensus among clinical researchers about whether the condition's name
should end in "syndrome" or "disorder".
A pervasive developmental
disorder, Asperger syndrome is distinguished by a pattern of symptoms rather
than a single symptom. It is characterized by qualitative impairment in social
interaction, by stereotyped and restricted patterns of behavior, activities and
interests, and by no clinically significant delay in cognitive development or
general delay in language. Intense
preoccupation with a narrow subject, one-sided verbosity, restricted prosody,
and physical clumsiness are typical of the condition, but are not required for
diagnosis.
The lack of demonstrated empathy is
possibly the most dysfunctional aspect of Asperger syndrome. Individuals
with AS experience difficulties in basic elements of social interaction, which
may include a failure to develop friendships or to seek shared enjoyments or
achievements with others (for example, showing others objects of interest), a
lack of social or emotional reciprocity, and impaired nonverbal
behaviors in areas such as eye contact, facial expression, posture, and gesture.
Unlike those with autism, people with AS are not usually withdrawn around
others; they approach others, even if awkwardly. For example a person with AS
may engage in a one-sided, long-winded speech about a favorite topic, while
misunderstanding or not recognizing the listener's feelings or reactions, such
as a need for privacy or haste to leave. This social
awkwardness has been called "active but odd". This
failure to react appropriately to social interaction may appear as disregard for
other people's feelings, and may come across as insensitive.
The cognitive ability of children with AS often allows them to articulate social
norms in a laboratory context,
where
they may be able to show a theoretical understanding of other people's emotions;
however, they typically have difficulty acting on this knowledge in fluid,
real-life situations. People with AS
may analyze and distill their observation of social interaction into rigid
behavioral guidelines, and apply these rules in awkward ways, such as forced eye
contact, resulting in a demeanor that appears rigid or socially naive. Childhood
desire for companionship can become numbed through a history of failed social
encounters.
The hypothesis that
individuals with AS are predisposed to violent or criminal behavior has been
investigated but is not supported by data. More evidence
suggests children with AS are victims rather than victimizers. A 2008
review found that an overwhelming number of reported violent criminals with AS
had coexisting psychiatric disorders such as schizoaffective disorder.
People with Asperger syndrome often display behavior, interests, and
activities that are restricted and repetitive and are sometimes abnormally
intense or focused. They may stick to inflexible routines, move in stereotyped and repetitive ways, or
preoccupy themselves with parts of objects.
Pursuit of specific and narrow areas of interest is one of the most striking
features of AS.
Individuals with AS may collect volumes of detailed information on a relatively
narrow topic such as dinosaurs or members of congress, without necessarily
having genuine understanding of the broader topic. For example, a
child might memorize camera model numbers while caring little about
photography. This
behavior is usually apparent by grade school, typically age 5 or 6 in the United
States. Although
these special interests may change from time to time, they typically become more
unusual and narrowly focused, and often dominate social interaction so much that
the entire family may become immersed. Because narrow topics often capture the
interest of children, this symptom may go unrecognized.
Stereotyped and repetitive motor behaviors are a core part of the diagnosis
of AS and other ASDs. They include hand
movements such as flapping or twisting, and complex whole-body movements. These are
typically repeated in longer bursts and look more voluntary or ritualistic than
tics, which are usually faster, less
rhythmical and less often symmetrical.
Although individuals with Asperger syndrome acquire language skills without
significant general delay and their speech typically lacks significant
abnormalities, language acquisition and use is often
atypical. Abnormalities
include verbosity, abrupt transitions, literal
interpretations and miscomprehension of nuance, use of metaphor meaningful only to the speaker, auditory perception deficits,
unusually pedantic, formal or
idiosyncratic
speech, and oddities in loudness, pitch, intonation, prosody,
and rhythm.
Three aspects of communication patterns are of clinical interest: poor
prosody, tangential and circumstantial speech, and marked verbosity. Although inflection and intonation may be
less rigid or monotonic than in autism, people with AS often have a limited
range of intonation: speech may be unusually fast, jerky or loud. Speech may
convey a sense of incoherence; the conversational style
often includes monologues about topics that bore the listener, fails to provide
context for comments, or fails to
suppress internal thoughts. Individuals with AS may fail to monitor whether the
listener is interested or engaged in the conversation. The speaker's conclusion
or point may never be made, and attempts by the listener to elaborate on the
speech's content or logic, or to shift to related topics, are often
unsuccessful.
Children with AS may have an unusually sophisticated vocabulary at a young
age and have been colloquially called "little professors", but have difficulty
understanding figurative language and tend to use
language literally. Children with AS appear to have particular weaknesses in areas of nonliteral language
that include humor, irony, and teasing. Although individuals with AS usually
understand the cognitive basis of humour they seem to lack understanding of the intent of
humor to share enjoyment with others. Despite
strong evidence of impaired humor appreciation, anecdotal reports of humor in
individuals with AS seem to challenge some psychological theories of AS and
autism.
Individuals with Asperger syndrome may have signs or symptoms that are
independent of the diagnosis, but can affect the individual or the family. These
include differences in perception and problems with motor skills, sleep, and
emotions.
Individuals with AS often have excellent auditory and visual
perception. Children with ASD
often demonstrate enhanced perception of small changes in patterns such as
arrangements of objects or well-known images; typically this is domain-specific
and involves processing of fine-grained features. Conversely, compared to individuals with high-functioning autism, individuals
with AS have deficits in some tasks involving visual-spatial perception,
auditory perception, or visual memory. Many
accounts of individuals with AS and ASD report other unusual sensory and
perceptual skills and experiences. They may be unusually sensitive or
insensitive to sound, light, touch, texture, taste, smell, pain, temperature,
and other stimuli, and they may exhibit synesthesia; these sensory
responses are found in other developmental disorders and are not specific to AS
or to ASD. There is little support for increased fight-or-flight response or failure of
habituation in autism; there
is more evidence of decreased responsiveness to sensory stimuli, although
several studies show no differences.
Hans Asperger's initial accounts
and other
diagnostic schemes include
descriptions of physical clumsiness. Children with AS may be delayed in
acquiring skills requiring motor dexterity, such as riding a bicycle or opening
a jar, and may seem to move awkwardly or feel "uncomfortable in their own skin".
They may be poorly coordinated, or have an odd or bouncy gait or posture, poor
handwriting, or problems with visual-motor integration. They may show
problems with proprioception (sensation of body position) on
measures of apraxia (motor planning
disorder), balance, tandem
gait, and finger-thumb apposition. There is no evidence that these motor
skills problems differentiate AS from other high-functioning ASDs.
Children with AS are more likely to have sleep problems, including difficulty
in falling asleep, frequent nocturnal awakenings, and early
morning awakenings.AS is also
associated with high levels of alexithymia, which is difficulty in identifying and
describing one's emotions. Although AS, lower
sleep quality, and alexithymia are associated, their causative relationship is
unclear.
As with other forms of ASD, parents of children with AS have higher levels of
stress.
Hans Asperger described common symptoms among his patients' family members,
especially fathers, and research supports this observation and suggests a
genetic contribution to Asperger syndrome. Although no specific gene has yet
been identified, multiple factors are believed to play a role in the expression of autism, given the
phenotypic variability seen in
this group of children. Evidence
for a genetic link is the tendency for AS to run in families and an observed
higher incidence of family members who have
behavioral symptoms similar to AS but in a more limited form (for example,
slight difficulties with social interaction, language, or reading). Most research
suggests that all autism spectrum disorders have shared
genetic mechanisms, but AS may have a stronger genetic component than
autism. There is
probably a common group of genes where particular alleles render an individual vulnerable to developing
AS; if this is the case, the particular combination of alleles would determine
the severity and symptoms for each individual with AS.
A few ASD cases have been linked to exposure to teratogens (agents that cause birth
defects) during the first eight weeks from conception. Although this does not exclude
the possibility that ASD can be initiated or affected later, it is strong
evidence that it arises very early in development. Many environmental factors have been
hypothesized to act after birth, but none has been confirmed by scientific
investigation.
Asperger syndrome appears to result from developmental factors that affect
many or all functional brain systems, as opposed to localized effects. Although
the specific underpinnings of AS or factors that distinguish it from other ASDs
are unknown, and no clear pathology common to individuals with AS has
emerged, it is
still possible that AS's mechanism is separate from other ASD. Neuroanatomical studies and the
associations with teratogens
strongly suggest that the mechanism includes alteration of brain development
soon after conception. Abnormal
migration of embryonic cells during fetal development
may affect the final structure and connectivity of the brain, resulting in
alterations in the neural circuits that control thought and behavior. Several theories
of mechanism are available; none is likely to provide a complete
explanation.
The underconnectivity theory hypothesizes underfunctioning high-level neural
connections and synchronization, along with an excess of low-level
processes. It maps well
to general-processing theories such as weak central coherence theory,
which hypothesizes that a limited ability to see the big picture underlies the
central disturbance in ASD.A related
theory—enhanced perceptual functioning—focuses more on the superiority of
locally oriented and perceptual operations in autistic individuals.
The mirror neuron
system (MNS) theory hypothesizes that alterations to the development of the
MNS interfere with imitation and lead to Asperger's core feature of social
impairment. For example, one
study found that activation is delayed in the core circuit for imitation in
individuals with AS.[45] This theory maps
well to social
cognition theories like the theory of mind, which hypothesizes that autistic
behavior arises from impairments in ascribing mental states to oneself and
others, or hyper-systemizing, which hypothesizes that
autistic individuals can systematize internal operation to handle internal
events but are less effective at empathizing by handling events generated by other
agents.
Other possible mechanisms include serotonin dysfunction
and cerebellar
dysfunction.
Parents of children with Asperger syndrome can typically trace differences in
their children's development to as early as 30 months of age.Developmental screening during a routine check-up by a general practitioner or pediatrician may
identify signs that warrant further investigation.The diagnosis
of AS is complicated by the use of several different screening instruments, including
the Asperger Syndrome Diagnostic Scale (ASDS), Autism Spectrum Screening
Questionnaire (ASSQ), Childhood Asperger Syndrome Test (CAST), Gilliam Asperger's Disorder
Scale (GADS), Krug Asperger's Disorder Index (KADI), and the Autism Spectrum Quotient (AQ; with
versions for children, adolescents and adults). None have been
shown to reliably differentiate between AS and other ASDs.
Standard diagnostic criteria require impairment in social interaction, and
repetitive and stereotyped patterns of behavior, activities and interests,
without significant delay in language or cognitive development. Unlike the
international standard, U.S.
criteria also require significant impairment in day-to-day functioning. Other sets
of diagnostic criteria have been proposed by Szatmari
et al. and by Gillberg
and Gillberg.
Diagnosis is most commonly made between the ages of four and eleven.
A
comprehensive assessment involves a multidisciplinary team that
observes across multiple settings, and
includes neurological and genetic assessment as well as tests for cognition,
psychomotor function, verbal and nonverbal strengths and weaknesses, style of
learning, and skills for independent living. The current
"gold standard" in diagnosing ASDs combines clinical judgment with the Autism Diagnostic
Interview-Revised (ADI-R)—a semistructured parent interview—and the Autism Diagnostic
Observation Schedule (ADOS)—a conversation and play-based interview with the
child. Delayed or mistaken diagnosis can be traumatic for individuals and families; for
example, misdiagnosis can lead to medications that worsen behavior. Many
children with AS are initially misdiagnosed with attention-deficit
hyperactivity disorder (ADHD). Diagnosing adults is more challenging, as standard diagnostic criteria are
designed for children and the expression of AS changes with age; adult diagnosis
requires painstaking clinical examination and thorough medical history gained
from both the individual and other people who know the person, focusing on
childhood behavior. Conditions that
must be considered in a differential diagnosis include other
ASDs, the schizophrenia
spectrum, ADHD, obsessive compulsive disorder, major
depressive disorder, semantic pragmatic disorder, nonverbal learning disorder,
Tourette
syndrome, stereotypic movement disorder and
bipolar
disorder.
Underdiagnosis and overdiagnosis are problems in marginal cases. The cost of
screening and diagnosis and the challenge of obtaining payment can inhibit or
delay diagnosis. Conversely, the increasing popularity of drug treatment options
and the expansion of benefits has motivated providers to overdiagnose ASD. There are
indications AS has been diagnosed more frequently in recent years, partly as a
residual diagnosis for children of normal intelligence who do not have autism
but have social difficulties. In
2006, it was reported to be the fastest-growing psychiatric diagnosis in Silicon Valley children;
also, there is a predilection for adults to self-diagnose it.There are questions about the external validity of the AS diagnosis. That
is, it is unclear whether there is a practical benefit in distinguishing AS from
HFA and from PDD-NOS; the
same child can receive different diagnoses depending on the screening tool.
The debate
about distinguishing AS from HFA is partly due to a tautological
dilemma where disorders are defined based on severity of impairment, so that
studies that appear to confirm differences based on severity are to be
expected.
Asperger syndrome treatment attempts to manage distressing symptoms and to
teach age-appropriate social, communication and vocational skills that are not
naturally acquired during development, with
intervention tailored to the needs of the individual child, based on
multidisciplinary assessment.Although progress
has been made, data supporting the efficacy of particular interventions are
limited.
The ideal treatment for AS coordinates therapies that address core symptoms
of the disorder, including poor communication skills and obsessive or repetitive
routines. While most professionals agree that the earlier the intervention, the
better, there is no single best treatment AS treatment
resembles that of other high-functioning ASDs, except that it takes into account
the linguistic capabilities, verbal strengths, and nonverbal vulnerabilities of
individuals with AS. A typical
program generally includes:
Of the many studies on behavior-based early intervention programs, most are
case
studies of up to five participants, and typically examine a few problem
behaviors such as self-injury,
aggression, noncompliance, stereotypies, or spontaneous
language; unintended side effects are largely ignored.
Despite
the popularity of social skills training, its effectiveness is not firmly
established. A randomized
controlled study of a model for training parents in problem behaviors in their
children with AS showed that parents attending a one-day workshop or six
individual lessons reported fewer behavioral problems, while parents receiving
the individual lessons reported less intense behavioral problems in their AS
children. Vocational
training is important to teach job interview etiquette and workplace behavior to
older children and adults with AS, and organization software and personal data
assistants to improve the work and life management of people with AS are
useful.
No medications directly treat the core symptoms of AS.Although
research into the efficacy of pharmaceutical intervention for AS is limited, it is
essential to diagnose and treat comorbid conditions.Deficits in
self-identifying emotions or in observing effects of one's behavior on others
can make it difficult for individuals with AS to see why medication may be
appropriate.Medication
can be effective in combination with behavioral interventions and environmental
accommodations in treating comorbid symptoms such as anxiety disorder, major
depressive disorder, inattention and aggression. The atypical
neuroleptic medications risperidone and olanzapine have been shown to reduce the associated
symptoms of AS;risperidone can reduce repetitive and self-injurious behaviors, aggressive
outbursts and impulsivity, and improve stereotypical patterns of behavior and
social relatedness. The selective serotonin reuptake
inhibitors (SSRIs) fluoxetine, fluvoxamine and sertraline have been effective in treating
restricted and repetitive interests and behaviors.[1][2][33]
Care must be taken with medications; abnormalities in metabolism, cardiac conduction
times, and an increased risk of type 2 diabetes have been raised as
concerns with these medications, along with
serious long-term neurological side effects.SRRIs can
lead to manifestations of behavioral activation such as increased impulsivity,
aggression and sleep disturbance.Weight gain and fatigue are
commonly reported side effects of risperidone, which may also lead to increased
risk for extrapyramidal symptoms such as restlessness and
dystonia and
increased serum prolactin
levels.Sedation and
weight gain are more common with olanzapine, which has
also been linked with diabetes. Sedative
side-effects in school-age children have ramifications
for classroom learning. Individuals with AS may be unable to identify and
communicate their internal moods and emotions or to tolerate side effects that
for most people would not be problematic.
There is some evidence that as many as 20% of children with AS "grow out" of
it, and fail to meet the diagnostic criteria as adults. As of
2006, no studies addressing the long-term outcome of individuals with Asperger
syndrome are available and there are no systematic long-term follow-up studies
of children with AS. Individuals
with AS appear to have normal life expectancy but have an increased prevalence of comorbid psychiatric conditions such as major depressive
disorder and anxiety disorder that may significantly affect prognosis. Although social impairment is lifelong,
outcome is generally more positive than with individuals with lower functioning
autism spectrum disorders; for
example, ASD symptoms are more likely to diminish with time in children with AS
or HFA. Although most
students with AS/HFA have average mathematical ability and test slightly worse
in mathematics than in general intelligence, some are gifted in mathematics
and AS has not
prevented some adults from major accomplishments such as winning the Nobel Prize.
Children with AS may require special education services because of their
social and behavioral difficulties although many attend regular education
classes. Adolescents
with AS may exhibit ongoing difficulty with self care, organization and disturbances in social
and romantic relationships; despite high cognitive potential, most young adults
with AS remain at home, although some do marry and work independently. The
"different-ness" adolescents experience can be traumatic. Anxiety may
stem from preoccupation over possible violations of routines and rituals, from
being placed in a situation without a clear schedule or expectations, or from concern with failing in
social encounters; the
resulting stress may manifest as inattention, withdrawal, reliance on
obsessions, hyperactivity, or aggressive or oppositional behavior. Depression
is often the result of chronic frustration from repeated failure to engage
others socially, and mood
disorders requiring treatment may develop.Clinical
experience suggests the rate of suicide may be higher among those with AS, but
this has not been confirmed by systematic empirical studies.
Education of families is critical in developing strategies for understanding
strengths and weaknesses; helping the
family to cope improves outcomes in children. Prognosis may be improved by diagnosis at a younger age that allows for early
interventions, while interventions in adulthood are valuable but less
beneficial. There are
legal implications for individuals with AS as they run the risk of exploitation
by others and may be unable to comprehend the societal implications of their
actions
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