| Disorders usually first diagnosed in infancy, childhood, or adolescence. |
Asperger’s Disorder--
Mental Asperger syndrome (also Asperger's syndrome, Asperger's disorder, Asperger's, or AS) is
one of several autism spectrum disorders (ASD) that are characterized by difficulties in social
communication and interaction, and in intense but narrow interests[1]. Asperger's have normal or
even superior intelligence[2] and, unlike autistics, have no significant delay in language development
[3] . Although not mentioned in standard diagnostic criteria, odd speech, language peculiarities and
abnormal clumsiness are frequently reported features of AS.[4][5]
Asperger syndrome was named in honor of Hans Asperger who, in 1944, described children in his
practice who appeared to have normal intelligence but lacked nonverbal communication skills, failed to
demonstrate empathy with their peers, and were physically clumsy. AS was introduced to the
English-speaking world in 1981 when British doctor Lorna Wing published a series of case studies
[1]. In 1994, AS was recognized in the Diagnostic and Statistical Manual of Mental Disorders (DSM-
IV) as Asperger's Disorder. Questions about many aspects of AS remain: the diagnostic validity of
Asperger syndrome is disputed, there is lingering doubt about the distinction between AS and high-
functioning autism (HFA)[6], and the prevalence of AS is unclear. Further, experienced clinicians use
characteristics beyond the diagnostic criteria to diagnose AS and to distinguish between AS and HFA.
There is no single treatment for AS, and there is little evidence that any particular intervention is
effective. Researchers and people with AS have contributed to a shift in attitudes, away from the
notion that AS is a deviation from the norm that must be treated or cured, and towards the view
that AS is a difference rather than a disability. Intervention is aimed at ameliorating symptoms and
improving function. The mainstay of treatment is behavioral therapy, focusing on specific deficits to
address poor communication skills, obsessive or repetitive routines, and clumsiness.
Most individuals with AS can learn to cope with their differences, but may continue to need moral
support and encouragement to maintain an independent life.[1] The deficits associated with AS may
be debilitating, but many individuals are able to excel, especially in areas that are less dependent on
social interaction, including mathematics, music, and computer sciences.[2]. The exact cause of AS is
unknown, although research supports the likelihood of a genetic contribution, and advanced brain
imaging techniques have identified structural and functional differences in specific regions of the brain.
Classification
Asperger syndrome is one of the pervasive developmental- (PDD) or autism spectrum disorders
(ASD), which are characterized by widespread abnormalities of social interaction and communication,
restricted interests and repetitive behavior.[7] Of the other four autism spectrum disorders, autism
is most similar to AS in signs and likely causes; 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 are not met for a more
specific disorder.[8] Unlike autism, AS has no substantial delay in language or cognitive development
under the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and World Health
Organization ICD-10 diagnostic criteria.[9]
The extent of the overlap between AS and high-functioning autism (HFA—autism unaccompanied by
mental retardation) is unclear;[10] there is significant debate over the difference between AS and
HFA and whether they are distinct and separate disorders.[11][12] Some clinicians deny that AS is
differentiated from other autistic spectrum disorders and indicate that a "DSM-IV diagnosis of
Asperger's disorder is unlikely or impossible".[13] Instead they refer to Asperger's as HFA, or treat
the diagnoses interchangeably, arguing that language delay is a difference in degree and not kind.[2]
[13] While HFA has no standardized definition, and AS has several distinct definitions,[14][15]
diagnosticians and other clinicians often distinguish the two according to speech development.[16]
[17][18] However, objective tests have yet to demonstrate the validity of this position,[11][16][17]
and at least one diagnostic guide takes the position that delayed speech may be a sign of AS.[19]
The diagnoses of AS or HFA are sometimes used interchangeably; the same child can receive
different diagnoses depending on the screening tool the doctor uses.[1] Some researchers argue
that there should be no boundary between high-functioning autism and AS, and that the fact that
some people do not start to produce speech until a later age is no reason to divide the two groups,
since they are identical in the way they need to be treated.[20] In some countries, diagnoses may be
influenced by non-technical issues, such as availability of government benefits for one condition but
not the other; clinicians may diagnose autism rather than the more correct Asperger's if that helps a
child receive classroom support, government funding or services covered by insurance.[21]
Canadian researcher Peter Szatmari writes that the current classification of the pervasive
developmental disorders is "deeply unsatisfying to many parents, front-line clinicians, and academic
researchers", and may not reflect the true nature of the conditions; he writes that the DSM-IV and
ICD-10 focus on the idea that discrete biological entities exist within PDD, which "leads to a
preoccupation with searching for cross-sectional differences between PDD subtypes, a strategy
which has not been very useful in classification or in clinical practice".[22]
Characteristics
AS is characterized in the DSM-IV by impairments in social interaction and restricted interests and
behaviors. [23] Intense preoccupation with a narrow subject, one-sided verbosity, restricted
prosody and intonation, and motor clumsiness are typical of the condition, but are not required for
a DSM-IV diagnosis;[6] these features are included in other diagnostic schemes (see Diagnosis).
Experienced clinicians use characteristics beyond the diagnostic criteria to distinguish between AS
and HFA.[6]
Although individuals with AS "have considerable verbal ability, they fail to utilize language
appropriately in social interactions" (UCLA's Kasari and Rotheram-Fuller).[11] "These are kids who
talk before they walk," according to Fred Volkmar, the director of the Yale Child Study Center.
"Words are their lifeline, and from a research perspective that's a critical observation that captures
the difference from autism."[24] The DSM-IV does not specify language delays, but clinicians
acknowledge abnormalities in speech and communication. Klin has written that "significant
abnormalities of speech are not typical of individuals with AS", but "aspects of these individuals'
communication patterns" are of clinical interest.[6]
With respect to the restricted interests of those with AS, "one of the most striking features of
individuals with AS is their passionate pursuit of specific areas of interest" (McPartland and Klin of the
Yale Child Study Center).[5]
Describing the social interaction of individuals with AS, Harvard Medical School's Baskin, Sperber and
Price have written that "the lack of empathy demonstrated by AS patients is possibly the most
dysfunctional aspect of the syndrome".[4]
Christopher Gillberg writes "Children with autism spectrum disorders, notably those with Asperger
syndrome, have long been reported to suffer from the kind of motor clumsiness currently subsumed
under the DCD [Developmental Coordination Disorder] label."[25]
Social interaction
Individuals with Asperger syndrome experience difficulties in the basic elements of social interaction,
which may be manifested in their impaired use of nonverbal behaviors such as eye contact, facial
expressions,[26] and bodily postures and gestures; a failure to develop friendships or enjoy
spontaneous interests or achievements with others; or deficient social or emotional reciprocity.[23]
People with AS have a lower capacity for empathy,[5] which was confirmed in a controlled study
comparing AS and HFA individuals[27] and has significant negative implications to people with AS.[28]
Within the family, children with AS may or may not bond or show affection, while outside the family,
they may make inappropriate attempts to socialize, leading to peer rejection.[2] Dating and marriage
present additional difficulties; men with AS may want to marry without an understanding of
courtship.[2] The concrete nature of emotional attachment for people with AS (for example,
attachment to objects rather than people) may seem curious or be a cause of concern to others,
[29] although the opposite may occur: a person with AS may be unusually affectionate to significant
others and not perceive or misinterpret signals from a partner.[30]
People with AS may find themselves socially isolated, although unlike those with autism, they are not
usually withdrawn around others; they approach others, even if awkwardly, for example by engaging
in a one-sided, long-winded speech about an unusual topic while being insensitive to or unaware of
the other person’s feelings or reactions, such as signs of boredom or wanting to leave.[6] This
failure to interpret the context of, or react appropriately to social interaction may appear as
disregard for other people's feelings, and may come across as highly insensitive. However, the
cognitive ability of people with AS sometimes permits them to articulate social norms in a laboratory
context,[5] where they may be able to describe social conventions and show a theoretical
understanding of other people’s emotions, but have difficulty acting on this knowledge in real-life
situations[6] and fluid social interactions.[5] People with AS may analyze and distill their observation
of social interaction into rigid behavioral guidelines, yet apply these rules in ways that are awkward—
such as forced eye contact—resulting in a demeanor that appears rigid or socially naïve.[5]
Repetitive behaviors and restricted interests
People with AS display restricted repetitive and stereotyped patterns of behavior, interests, and
activities that can include interests that are abnormal in intensity or focus, inflexible adherence to
routines or rituals, stereotyped and repetitive motor mannerisms, or a preoccupation with parts of
objects.[23]
Individuals with AS may amass volumes of detailed information on unusual topics of special interest
[6][5]. While many children have developmentally appropriate interests in topics such as dinosaurs
or trains, a child with AS may also be interested in transistors, subway tokens, deep fat fryers, or
members of congress. These interests may have an exclusive, obsessive quality and an absence of
genuine understanding of broader phenomena related to the topic.[6][5] For example, "a child might
be interested in memorizing the model numbers of antique cameras without any interest in
photography".[5] Asperger described good memory for trivial facts (occasionally even eidetic
memory) in some of his patients;[31] [32] but, despite occasional appearances to the contrary,[33]
this may involve more rote memorization than real understanding.[31]
The passionate pursuit of special interests is usually apparent by the time children with AS enter
grade school (typically age 5 or 6 in the US). This may be at the expense of their developing typical
peer relationships or pursuing other activities.[2][5] The topic of interest may change over time, but
often dominates social relationships, contributing to the social difficulties accompanying AS.[6][5]
The entire family may become immersed in the narrow topic of interest.[6] Because topics such as
dinosaurs and fictional characters often capture the interest of children, this symptom may go
unrecognized, and may not be apparent until the interests become more unusual and focused over
time.[6]
Special interests may dominate the social interaction of a child with AS and the monologues
characteristic of their preoccupations may alienate other children. They are "notoriously oblivious" to
the effect their conversation is having on the listener, and their excessive enthusiasm to share the
interest with others causes them to engage in a socially awkward manner that has been called "active
but odd".[5] Childhood desires for social companionship can be numbed through a history of failed
social encounters.[5]
Stereotyped and repetitive motor mannerisms may involve hand movements such as flapping or
twisting, or complex whole-body movements;[23] people with AS may display compulsive finger,
hand, arm or leg movements,[34] including tics and stims.[35][36] Stereotypies are typically
repeated in longer bursts and look more voluntary or ritualistic than tics, which are usually faster,
less rhythmical and more often asymmetrical than stereotypies. Although there is overlap,
experienced clinicians rarely have difficulty distinguishing tics from stereotypies.[37]
Speech and language
Although language skills are not mentioned in the DSM-IV or ICD-10 diagnostic criteria, there is
evidence that while children with AS acquire language on time, their use of language may be atypical;
[5] "speech and language peculiarities" and "odd speech" are included in other diagnostic schemes.
[23][19] Individuals with AS may demonstrate abnormal speech and language, including pedantic
speech; oddities in pitch, intonation, prosody, and rhythm; literal interpretations and
miscomprehension of nuance; a lack of sensitivity or an inability to use language in social contexts
(for example, interrupting others or inserting irrelevant commentary and inappropriate personal
remarks); unusually formal or idiosyncratic speech; verbosity, speech reflecting the idiosyncratic
interests of the speaker or the use of metaphors meaningful only to the individual; selective mutism;
and auditory discrimination issues, particularly when multiple people are speaking simultaneously.[2]
According to Klin, at least three aspects of these individuals' communication patterns are of clinical
interest: poor prosody, tangential and circumstantial speech, and marked verbosity.[6] 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 overly fast, jerky or loud. Speech may convey a sense of
incoherence; although some of these cases may be symptomatic of a thought disorder, there is
often a conversational style that includes monologues about topics of little or no interest the
listener, a failure to provide context or background for comments, and a failure to suppress internal
thoughts. Individuals with AS may talk incessantly about a favorite topic, and may fail to monitor
whether the listener is interested or engaged in the conversation. The conclusion or point of long-
winded monologues may never be made, and attempts by the listener to elaborate on the content or
logic of the exchange, or to shift the focus to related topics, are often unsuccessful.[6]
Children with AS may have an unusually sophisticated vocabulary at a young age (and have been
colloquially referred to as "little professors") but have difficulty understanding metaphorical language
and tend to use language literally.[5][38] Autism researcher Tony Attwood gives the example of a
girl with AS who answered the telephone and was asked, "Is Paul there?" Although Paul was in the
house, he was not in the room with her, so she said "no" and hung up. The caller had to call back
and explain that he meant for her to find Paul and have him pick up the telephone.[39] Individuals
with AS appear to have particular weaknesses in several areas of nonliteral language, including
humor, irony and teasing.[11] A study analyzing adolescents’ responses to cartoons found that
individuals with AS and HFA had difficulty comprehending humor.[40] Another study of young adults
with AS found they understood ironic jokes less readily than typical controls and were poor at using
social context to interpret conversational meaning;[41] people with AS usually understand the
cognitive basis of humor, but may lack understanding of the intent of humor—to "share enjoyment
with others".[11]
Other
Problems with motor skills are not part of the DSM-IV diagnostic criteria, but Asperger’s initial
accounts[5] and other diagnostic schemes[19] include descriptions of motor clumsiness. Children
with AS may be delayed in acquiring motor skills that require motor dexterity, such as bicycle riding
or opening a jar, and may appear awkward or "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, visual–perceptual skills, and conceptual learning,[6][5] while having "relative
strengths in auditory and verbal skills and rote learning".[6] Research also shows problems with
proprioception and "deficits on measures of apraxia, balance tandem gait, and finger–thumb
apposition".[42] There is no evidence that these motor skills problems differentiate AS from other
high-functioning ASDs.[5]
Children with AS may be sensitive to sound (hyperacusis), touch, taste, sight, smell, pain,
temperature, and the texture of foods; they may exhibit synesthesia,[2] a neurologically based
phenomenon in which the stimulation of one sensory or cognitive pathway leads to automatic,
involuntary experiences in a second sensory or cognitive pathway. A review of all controlled
investigations published since 1960 showed that sensory symptoms were more frequent in children
with autism, but there was little support for hyperarousal or habituation in autism; there was
evidence of hyporesponsiveness to sensory stimuli, although many of these findings have not been
replicated.[43]
According to McPartland and Klin (2006), a unique neuropsychological profile has been described for
AS and confirmed in a review of the literature;[44] if verified, it could differentiate between AS and
HFA and aid in differential diagnosis. Relative to HFA, people with AS have deficits in "fine and gross
motor skills; visual motor integration; visual-spatial perception; nonverbal concept formation; and
visual memory with preserved articulation, verbal output, auditory perception, vocabulary, and verbal
memory".[45] Verbal abilities are stronger than performance abilities and indicate weakness in visual–
spatial organization and graphomotor skills.[46] Most subjects with AS in another study had a
"neuropsychologic profile consistent with a nonverbal learning disability".[47] The literature review did
not reveal consistent findings of "nonverbal weaknesses or increased spatial or motor problems
relative to individuals with HFA", leading some researchers to argue that increased cognitive ability is
evidenced in AS relative to HFA regardless of differences in verbal and nonverbal ability.[48]
Alexithymia is a personality trait of people who have difficulty recognizing, processing and regulating
emotions.[49] Uta Frith reported that alexithymia overlaps with AS, and that at least half of the
Asperger syndrome subjects in a study obtained scores that indicate severe impairment.[50] Other
researchers concur that both conditions are characterized by core disturbances in speech and
language and social relationships[51][52] and the limbic system and prefrontal cortex may be
involved in both.[4][53] Alexithymic traits in AS may be linked to depression or anxiety;[50] the
mediating factors are unknown and it is possible that alexithymia predisposes a person to anxiety.
[53]
Diagnosis of Asperger syndrome
Asperger's Disorder is defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV)
by six main criteria.[23]
The ICD-10 criteria are almost identical to DSM-IV:[54] ICD-10 adds the statement that motor
clumsiness is usual (although not necessarily a diagnostic feature); ICD-10 adds the statement that
isolated special skills, often related to abnormal preoccupations, are common but are not required for
diagnosis; and the DSM-IV requirement for clinically significant impairment in social, occupational, or
other important areas of functioning is not included in ICD-10.[55][4]
The DSM-IV and ICD-10 diagnostic criteria have been criticized for being too broad and inadequate
for assessing adults,[56] overly narrow (particularly in relation to Hans Asperger's original
description of individuals with AS),[13][54] and vague;[19] results of a large study in 2007
comparing the four sets of criteria point to a "huge need to reconsider the diagnostic criteria of AS."
[55] The study found complete overlap across all sets of diagnostic criteria in the impairment of
social interaction with the exception of four cases not diagnosed by the Szatmari et al. criteria
because of its emphasis on social solitariness. Lack of overlap was strongest in the language delay
and odd speech requirements of the Gillberg and the Szatmari requirements relative to DSM-IV and
ICD-10, in the differing requirements regarding general delays, and in DSM's requirement for
impairment.[55]
Signs suggestive of AS are often noted by a general practitioner or pediatrician during a routine
developmental check up. The National Institute of Neurological Disorders and Stroke advise that this
be followed up with a comprehensive team evaluation to either confirm or exclude a diagnosis of AS.
[5] Foster and King state that the determination of whether there is a family history of autism
spectrum conditions can be important.[57] Fitzgerald states that a multidisciplinary team approach
can be critical to avoiding misdiagnosis;:[54] an accurate assessment of the individual's strengths
and weaknesses is claimed to be more useful than a diagnostic label.[5] Delayed or mistaken
diagnosis is regarded as a serious problem that can be traumatic for individuals and families;
diagnosis based solely on a neurological, speech and language, or educational attainment may yield
only a partial diagnosis.[54]
It has been found that parents of children with AS can typically trace differences in their children's
development to as early as 30 months of age, although diagnosis is not made on average until the
age of 11.[57] By definition, children with AS develop language and self-help skills on schedule, so
early signs may not be apparent and the condition may not be diagnosed until later childhood.
Impairment in social interaction is sometimes not in evidence until a child attains an age at which
these behaviors become important; social disabilities are often first noticed when children encounter
peers in daycare or preschool.[5] Diagnosis is most commonly made between the ages of four and
eleven, and one study suggests that diagnosis cannot be rendered reliably before age four.[5]
Asperger syndrome can be misdiagnosed as a number of other conditions, leading to medications
that are unnecessary or even worsen behavior.[54]
Causes of autism
Asperger described common symptoms among his patients' family members, especially fathers,[5]
and research supports this observation and suggests a genetic contribution to AS.[5][57] 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.[57] 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).[1] Most research suggests that all autism
spectrum disorders have shared genetic mechanisms, but AS may have a stronger genetic
component than autism.[5] 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.[1] No gene has been
identified for AS, although studies suggest specific genetic abnormalities: such as various types of
chromosomal translocations in chromosomes 1, 5, 11, 13, 14, 15 and 17; autosomal fragile site,
fragile X syndrome, fragile Y, and 21pþ.[5] Anomalies in chromosome 22 were related to the
diagnosis of autism and Asperger syndrome in five children. The distal tip of the long arm of the
chromosome 22 contains the SHANK3 gene, which is thought to have a role in the maturation and
maintenance of brain synapses. The deletion of this part of the chromosome (22q13 deletion
syndrome) was found in low-functioning autistic subjects, and its duplication observed in a subject
diagnosed with Asperger syndrome.[58]
Environmental factors may interact with genetic influences to play a role in the cause of ASDs, but
research has identified no consistent correlations.[5] There is strong evidence that genetic factors
play a major role in the causes of autism spectrum disorders, while none of the possible
environmental causes has been confirmed by scientific investigation.[59]
Mechanism
Brain imaging techniques have revealed structural and functional differences in specific regions of the
brains of AS children; these are most likely caused by the abnormal migration of embryonic cells
during fetal development, which affects the final structure and connectivity of the brain, resulting in
alterations in the neural circuits that control thought and behavior.[1] Although progress has been
made, brain imaging technologies have failed to identify the specific underpinnings of AS or factors
that distinguish it from other ASDs and no clear pathology common to individuals with AS has
emerged.[5] Functional MRI has provided interesting findings, but no convincing evidence
reproducibly indicates differences among AS and other ASDs.[5]
One study reported a reduction of brain activity in the frontal lobe of AS children when they were
asked to respond to tasks that required them to use their judgment. These differences in activity
were also seen when children were asked to respond to facial expressions.[1] Another study, of
brain function in adults with AS, revealed abnormal levels of some proteins and demonstrated a
correlation between these levels and obsessive and repetitive behaviors.[1] Possible differences in
AS include:[5] gray tissue anomalies,[60][61] left temporal lobe damage,[62] and left occipital
hypoperfusion.[63] Other possible causative mechanisms include serotonin dysfunction and
cerebellar dysfunction.[64][65] Differences in brain volumes—such as enlarged amygdala and
hippocampus—have been linked to autism;[66] the most robust findings are of the reduced size of
the corpus callosum and rapid brain growth and increased brain volume in early childhood that
normalizes in mid-childhood.[67] Other research suggests abnormal right hemisphere functioning in
AS,[68] dysfunction in brain regions affecting social cognition,[69] and problems with functional
connectivity among separate brain regions.[70]
Simon Baron-Cohen proposes a model for Asperger's[71] that extends the extreme male brain
theory, which hypothesizes that autism is an extreme case of the male brain, defined psycho-
metrically as individuals in whom systemizing is better than empathizing.[72] Hyper-systemizing
hypothesizes that autistic individuals can systematize—that is, they can develop internal rules of
operation to handle internal events—but are less effective at empathizing by handling events
generated by other agents.[73] This in turn is related to the earlier theory of mind, which
hypothesizes that autistic behavior arises from an inability to ascribe mental states to oneself and
others.[74] Two studies showed that Asperger subjects had a second-order theory of mind;
compared to younger or more impaired autistic individuals, they were able to understand problems
of the type "Peter thinks that Jane thinks that ..." although their explanationns of their solutions did
not use mental states.[75] There is some evidence that the mind-reading capacity of children in the
higher-functioning range of the autistic spectrum are intact.[76]
Autism therapies
The goal of treatment is the development of age-appropriate social, communication and vocational
abilities, and the successful management of distressing symptoms, aiming to teach through explicit
instruction the skills that are not naturally acquired during development.[5] Intervention should be
tailored to the needs of the individual child, based on multidisciplinary assessment.[77] Although
progress has been made, data supporting the efficacy of particular interventions are limited.[5]
The ideal treatment for AS coordinates therapies that address the three core symptoms of the
disorder: poor communication skills, obsessive or repetitive routines, and physical clumsiness. While
most professionals agree that the earlier the intervention, the better, there is no single best
treatment package.[1] 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.[5] A typical treatment program generally includes:[1]
* the training of social skills for more effective interpersonal interactions;
* cognitive behavioral therapy to improve the management of anxiety or explosive emotions, and to
reduce the prevalence of obsessive interests and repetitive routines;
* medication, for coexisting conditions such as depression and anxiety;
* occupational or physical therapy to assist with poor sensory integration and motor coordination;
* specialized speech therapy, to help with the pragmatics of the "give and take" of normal
conversation;
* the training and support of parents, particularly in behavioral techniques to use in the home.
There have been many studies on psychologically based early intervention programs; most of these
are case studies of up to five participants.[78] These studies typically examine non-core autistic
problem behaviors such as self-injury, aggression, noncompliance, stereotypies and spontaneous
language.[78] Despite the widespread application of social skills training, its effectiveness is not
firmly established.[79] A randomized controlled study of a model for training parents in problem
behaviors in their children with AS showed that parents attending a 1-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.[80] 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.[5]
No medications specifically target AS[4] or directly treat the core symptoms of autism spectrum
disorders; research into the efficacy of pharmaceutical intervention for AS is limited.[5] However, it is
essential to diagnose and treat comorbid conditions;[4] medication can be effective in combination
with behavioral interventions and environmental accommodations in treating comorbid symptoms
such as anxiety, depression, inattention and aggression.[5] The atypical neuroleptic medications
risperidone and olanzapine have been shown to reduce the associated symptoms of AS;[5]
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
repetitive behaviors and restricted interests.[4][57][5]
Care must be taken in the management of pharmacotherapy; abnormalities in metabolism, cardiac
conduction times, and an increased risk of type 2 diabetes have been raised as concerns with these
medications[81][82] and unintended side effects have largely been ignored in the literature.[78]
SSRIs can lead to manifestations of behavioral activation such as increased impulsivity, aggression
and sleep disturbance.[57] 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[57] and increased serum prolactin levels.[83] Sedation and weight gain are more
common with olanzapine,[82] which has also been linked with diabetes.[81] Sedative side-effects in
school-age children[84] 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.[12]
Prognosis
As of 2006, no studies addressing the long-term outcome of individuals with AS are available and
there are no systematic long-term follow-up studies of children with AS.[6] Individuals with AS
appear to have normal life expectancy but have an increased prevalence of comorbid psychiatric
conditions such as depression, mood disorders, and obsessive-compulsive disorder that may
significantly affect prognosis. Although the social impairment is believed to be lifelong,[2] outcome is
generally more positive than with individuals with lower functioning autism spectrum disorders.[5][90]
Children with AS are vulnerable to being teased and victimized; some may require special education
services because of their social and behavioral difficulties although many attend regular education
classes.[6] Adolescents with AS may exhibit ongoing difficulty with self-care, organization and
disturbances in social and romantic relationships;[91] despite high cognitive potential, most remain
at home, although some do marry and work independently.[5][92] The "different-ness" adolescents
experience can be traumatic.[24] Although the deficits associated with AS are often debilitating,
many individuals experience positive outcomes—particularly those who are able to excel in areas less
dependent on social interaction, such as mathematics, music, and the sciences. Reports suggest
that many people with AS are highly creative and accomplish innovative research in fields such as
computer science, mathematics, and physics.[2] Baron-Cohen reports a link between AS and high-
achieving mathematicians, physicists and computer scientists that shows that the condition need not
be an obstacle to achievement.[93] The symptoms of AS can at some point "fade to normal" and
people with AS can become valued workers as adults because of the "intensity of interest and
volume of knowledge" that they may bring to idiosyncratic subjects,[24] but they may lose
employment if impaired understanding of social norms leads to poor judgment in work site behavior.
[2]
Education of families is critical in developing strategies for understanding strengths and weaknesses;
[4] prognosis is improved when individuals with AS have supportive families who are knowledgeable
about Asperger's.[2] Prognosis may be improved by diagnosis at a younger age that allows for early
interventions, while interventions in adulthood are valuable but less beneficial.[4] 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.[4] The hypothesis that the combination of
intact intellectual and linguistic ability with limited empathy and social understanding may predispose
individuals with AS to violent or criminal behavior has been investigated and found to be
unsupported by data.[5][94]
Epidemiology
The incidence of AS is not well established, but conservative estimates using the DSM-IV criteria
indicate that two to three of every 10,000 children have the condition, making it rarer than autistic
disorder itself.[1][95] A computerized registry in Denmark indicates an annual incidence of 1.4 per
10,000 for AS.[4] Advocacy and parent support organizations have proliferated around the concept
of AS, and there are indications that this has resulted in more frequent diagnoses of AS, which may
be given as a "residual diagnosis" to children of normal intelligence who do not meet diagnostic
criteria for autism but have some social difficulties.[6]
A 2003 review of epidemiological studies[96] found prevalence rates ranging from .03 to 4.8 per
1,000; the authors suggested a working rate of .26 per 1,000.[5] A 1993 Sweden study found the
prevalence of AS was 3.6 per 1,000 among school-aged children aged 7–16 using Gillberg's criteria,
rising to 7.1 per 1,000 if suspected cases are included.[19] The estimate is convincing for Sweden,
but the findings may not apply elsewhere because they are based on a homogeneous population.[2]
Prevalence estimates vary according to the diagnostic criteria employed. An epidemiological study of
5,484 eight-year-old children in Finland found 2.9 children per 1,000 met the ICD-10 criteria for an
AS diagnosis, 2.7 per 1,000 for Gillberg and Gillberg criteria, 2.5 for DSM-IV and 1.6 for Szatmari et
al. The number of children diagnosed as having AS according to any of the four criteria was 4.3 per
1,000.[55] Leekam et al. documented significant differences between Gillberg's criteria and the ICD-
10 criteria.[97]
Like other autism spectrum disorders, AS prevalence estimates for males are higher than for females.
[1] The Sweden study found a 4:1 male to female ratio in subjects meeting Gillberg's criteria for AS,
but a lower 2.3:1 ratio when suspected or borderline cases were included.[19] The Finland study
found a "somewhat surprising" male-to-female ratio according to DSM-IV criteria of 0.8:1; Gillberg
and Gillberg criteria yielded a 2:1 ratio and the ratio when including children diagnosed per any of the
four sets of diagnostic criteria was 1.7:1. Females with AS may not be recognized in studies as they
tend to be superficially more sociable than boys, although closer examination reveals problems in
social interaction.[55]
Comorbidities
Most patients presenting in clinical settings with AS have other comorbid psychiatric disorders;
children are likely to present with attention-deficit hyperactivity disorder (ADHD), while depression is
a common diagnosis in adolescents and adults.[98] Many children with AS are initially misdiagnosed
with ADHD.[5] Individuals with AS may also be diagnosed with oppositional defiant disorder,
antisocial personality disorder, tic disorders and Tourette syndrome, general anxiety disorder, bipolar
disorder, obsessive compulsive disorder or obsessive-compulsive personality disorder.[99]
The conditions most commonly seen are depression and anxiety; comorbidity of these in persons
with AS is estimated at 65%. Anxiety may stem from preoccupation over possible violations of
routines and rituals or result from being placed in a situation without a clear schedule or
expectations. Social anxiety (concern with failing in social encounters) may also manifest. Depression
is often the result of chronic frustration from repeated failure to engage others socially, and mood
disorders requiring treatment may develop.[5]
The particularly high comorbidity with anxiety often requires special attention; one study reported
that about 84% of individuals with a pervasive developmental disorder also met the criteria for
anxiety disorder.[100] Because of the social differences experienced by those with AS, such as
trouble initiating or maintaining a conversation or adherence to strict rituals or schedules, additional
stress to any of these activities may result in feelings of anxiety, which can negatively affect multiple
areas of one's life, including school, family, and work. Anxiety disorders can be treated with
medication or individual and group cognitive behavioral therapy, where relaxation or distraction-type
activities may be used along with other techniques to diffuse the feelings of anxiety.[101]
Psychosocial factors may contribute to poor adjustment or psychiatric issues. An Internet survey of
middle-class mothers of children with AS and nonverbal learning disorders found peer and sibling
victimization of the children was common; 94% of mothers reported peer victimization of their
children. According to the mothers, in the year leading up to the study, almost three-quarters of the
children had been hit by peers or siblings and 75% had been emotionally bullied. More seriously,
10% of the children were attacked by a gang and 15% were victims of nonsexual assaults to the
genitals. Many of the children ate alone at lunch or were picked last for sports teams, and a third had
not been invited to a birthday party in the past year.[102]
Reports have associated AS with medical conditions such as aminoaciduria and ligamentous laxity,
but these have been case reports or small studies and no factors have been associated with AS
across studies.[5] An increased rate of epilepsy is reported in individuals with AS, and there is a high
rate (51%) of non-verbal learning disability.[103]
* References provided upon request.
Mental Asperger syndrome (also Asperger's syndrome, Asperger's disorder, Asperger's, or AS) is
one of several autism spectrum disorders (ASD) that are characterized by difficulties in social
communication and interaction, and in intense but narrow interests[1]. Asperger's have normal or
even superior intelligence[2] and, unlike autistics, have no significant delay in language development
[3] . Although not mentioned in standard diagnostic criteria, odd speech, language peculiarities and
abnormal clumsiness are frequently reported features of AS.[4][5]
Asperger syndrome was named in honor of Hans Asperger who, in 1944, described children in his
practice who appeared to have normal intelligence but lacked nonverbal communication skills, failed to
demonstrate empathy with their peers, and were physically clumsy. AS was introduced to the
English-speaking world in 1981 when British doctor Lorna Wing published a series of case studies
[1]. In 1994, AS was recognized in the Diagnostic and Statistical Manual of Mental Disorders (DSM-
IV) as Asperger's Disorder. Questions about many aspects of AS remain: the diagnostic validity of
Asperger syndrome is disputed, there is lingering doubt about the distinction between AS and high-
functioning autism (HFA)[6], and the prevalence of AS is unclear. Further, experienced clinicians use
characteristics beyond the diagnostic criteria to diagnose AS and to distinguish between AS and HFA.
There is no single treatment for AS, and there is little evidence that any particular intervention is
effective. Researchers and people with AS have contributed to a shift in attitudes, away from the
notion that AS is a deviation from the norm that must be treated or cured, and towards the view
that AS is a difference rather than a disability. Intervention is aimed at ameliorating symptoms and
improving function. The mainstay of treatment is behavioral therapy, focusing on specific deficits to
address poor communication skills, obsessive or repetitive routines, and clumsiness.
Most individuals with AS can learn to cope with their differences, but may continue to need moral
support and encouragement to maintain an independent life.[1] The deficits associated with AS may
be debilitating, but many individuals are able to excel, especially in areas that are less dependent on
social interaction, including mathematics, music, and computer sciences.[2]. The exact cause of AS is
unknown, although research supports the likelihood of a genetic contribution, and advanced brain
imaging techniques have identified structural and functional differences in specific regions of the brain.
Classification
Asperger syndrome is one of the pervasive developmental- (PDD) or autism spectrum disorders
(ASD), which are characterized by widespread abnormalities of social interaction and communication,
restricted interests and repetitive behavior.[7] Of the other four autism spectrum disorders, autism
is most similar to AS in signs and likely causes; 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 are not met for a more
specific disorder.[8] Unlike autism, AS has no substantial delay in language or cognitive development
under the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) and World Health
Organization ICD-10 diagnostic criteria.[9]
The extent of the overlap between AS and high-functioning autism (HFA—autism unaccompanied by
mental retardation) is unclear;[10] there is significant debate over the difference between AS and
HFA and whether they are distinct and separate disorders.[11][12] Some clinicians deny that AS is
differentiated from other autistic spectrum disorders and indicate that a "DSM-IV diagnosis of
Asperger's disorder is unlikely or impossible".[13] Instead they refer to Asperger's as HFA, or treat
the diagnoses interchangeably, arguing that language delay is a difference in degree and not kind.[2]
[13] While HFA has no standardized definition, and AS has several distinct definitions,[14][15]
diagnosticians and other clinicians often distinguish the two according to speech development.[16]
[17][18] However, objective tests have yet to demonstrate the validity of this position,[11][16][17]
and at least one diagnostic guide takes the position that delayed speech may be a sign of AS.[19]
The diagnoses of AS or HFA are sometimes used interchangeably; the same child can receive
different diagnoses depending on the screening tool the doctor uses.[1] Some researchers argue
that there should be no boundary between high-functioning autism and AS, and that the fact that
some people do not start to produce speech until a later age is no reason to divide the two groups,
since they are identical in the way they need to be treated.[20] In some countries, diagnoses may be
influenced by non-technical issues, such as availability of government benefits for one condition but
not the other; clinicians may diagnose autism rather than the more correct Asperger's if that helps a
child receive classroom support, government funding or services covered by insurance.[21]
Canadian researcher Peter Szatmari writes that the current classification of the pervasive
developmental disorders is "deeply unsatisfying to many parents, front-line clinicians, and academic
researchers", and may not reflect the true nature of the conditions; he writes that the DSM-IV and
ICD-10 focus on the idea that discrete biological entities exist within PDD, which "leads to a
preoccupation with searching for cross-sectional differences between PDD subtypes, a strategy
which has not been very useful in classification or in clinical practice".[22]
Characteristics
AS is characterized in the DSM-IV by impairments in social interaction and restricted interests and
behaviors. [23] Intense preoccupation with a narrow subject, one-sided verbosity, restricted
prosody and intonation, and motor clumsiness are typical of the condition, but are not required for
a DSM-IV diagnosis;[6] these features are included in other diagnostic schemes (see Diagnosis).
Experienced clinicians use characteristics beyond the diagnostic criteria to distinguish between AS
and HFA.[6]
Although individuals with AS "have considerable verbal ability, they fail to utilize language
appropriately in social interactions" (UCLA's Kasari and Rotheram-Fuller).[11] "These are kids who
talk before they walk," according to Fred Volkmar, the director of the Yale Child Study Center.
"Words are their lifeline, and from a research perspective that's a critical observation that captures
the difference from autism."[24] The DSM-IV does not specify language delays, but clinicians
acknowledge abnormalities in speech and communication. Klin has written that "significant
abnormalities of speech are not typical of individuals with AS", but "aspects of these individuals'
communication patterns" are of clinical interest.[6]
With respect to the restricted interests of those with AS, "one of the most striking features of
individuals with AS is their passionate pursuit of specific areas of interest" (McPartland and Klin of the
Yale Child Study Center).[5]
Describing the social interaction of individuals with AS, Harvard Medical School's Baskin, Sperber and
Price have written that "the lack of empathy demonstrated by AS patients is possibly the most
dysfunctional aspect of the syndrome".[4]
Christopher Gillberg writes "Children with autism spectrum disorders, notably those with Asperger
syndrome, have long been reported to suffer from the kind of motor clumsiness currently subsumed
under the DCD [Developmental Coordination Disorder] label."[25]
Social interaction
Individuals with Asperger syndrome experience difficulties in the basic elements of social interaction,
which may be manifested in their impaired use of nonverbal behaviors such as eye contact, facial
expressions,[26] and bodily postures and gestures; a failure to develop friendships or enjoy
spontaneous interests or achievements with others; or deficient social or emotional reciprocity.[23]
People with AS have a lower capacity for empathy,[5] which was confirmed in a controlled study
comparing AS and HFA individuals[27] and has significant negative implications to people with AS.[28]
Within the family, children with AS may or may not bond or show affection, while outside the family,
they may make inappropriate attempts to socialize, leading to peer rejection.[2] Dating and marriage
present additional difficulties; men with AS may want to marry without an understanding of
courtship.[2] The concrete nature of emotional attachment for people with AS (for example,
attachment to objects rather than people) may seem curious or be a cause of concern to others,
[29] although the opposite may occur: a person with AS may be unusually affectionate to significant
others and not perceive or misinterpret signals from a partner.[30]
People with AS may find themselves socially isolated, although unlike those with autism, they are not
usually withdrawn around others; they approach others, even if awkwardly, for example by engaging
in a one-sided, long-winded speech about an unusual topic while being insensitive to or unaware of
the other person’s feelings or reactions, such as signs of boredom or wanting to leave.[6] This
failure to interpret the context of, or react appropriately to social interaction may appear as
disregard for other people's feelings, and may come across as highly insensitive. However, the
cognitive ability of people with AS sometimes permits them to articulate social norms in a laboratory
context,[5] where they may be able to describe social conventions and show a theoretical
understanding of other people’s emotions, but have difficulty acting on this knowledge in real-life
situations[6] and fluid social interactions.[5] People with AS may analyze and distill their observation
of social interaction into rigid behavioral guidelines, yet apply these rules in ways that are awkward—
such as forced eye contact—resulting in a demeanor that appears rigid or socially naïve.[5]
Repetitive behaviors and restricted interests
People with AS display restricted repetitive and stereotyped patterns of behavior, interests, and
activities that can include interests that are abnormal in intensity or focus, inflexible adherence to
routines or rituals, stereotyped and repetitive motor mannerisms, or a preoccupation with parts of
objects.[23]
Individuals with AS may amass volumes of detailed information on unusual topics of special interest
[6][5]. While many children have developmentally appropriate interests in topics such as dinosaurs
or trains, a child with AS may also be interested in transistors, subway tokens, deep fat fryers, or
members of congress. These interests may have an exclusive, obsessive quality and an absence of
genuine understanding of broader phenomena related to the topic.[6][5] For example, "a child might
be interested in memorizing the model numbers of antique cameras without any interest in
photography".[5] Asperger described good memory for trivial facts (occasionally even eidetic
memory) in some of his patients;[31] [32] but, despite occasional appearances to the contrary,[33]
this may involve more rote memorization than real understanding.[31]
The passionate pursuit of special interests is usually apparent by the time children with AS enter
grade school (typically age 5 or 6 in the US). This may be at the expense of their developing typical
peer relationships or pursuing other activities.[2][5] The topic of interest may change over time, but
often dominates social relationships, contributing to the social difficulties accompanying AS.[6][5]
The entire family may become immersed in the narrow topic of interest.[6] Because topics such as
dinosaurs and fictional characters often capture the interest of children, this symptom may go
unrecognized, and may not be apparent until the interests become more unusual and focused over
time.[6]
Special interests may dominate the social interaction of a child with AS and the monologues
characteristic of their preoccupations may alienate other children. They are "notoriously oblivious" to
the effect their conversation is having on the listener, and their excessive enthusiasm to share the
interest with others causes them to engage in a socially awkward manner that has been called "active
but odd".[5] Childhood desires for social companionship can be numbed through a history of failed
social encounters.[5]
Stereotyped and repetitive motor mannerisms may involve hand movements such as flapping or
twisting, or complex whole-body movements;[23] people with AS may display compulsive finger,
hand, arm or leg movements,[34] including tics and stims.[35][36] Stereotypies are typically
repeated in longer bursts and look more voluntary or ritualistic than tics, which are usually faster,
less rhythmical and more often asymmetrical than stereotypies. Although there is overlap,
experienced clinicians rarely have difficulty distinguishing tics from stereotypies.[37]
Speech and language
Although language skills are not mentioned in the DSM-IV or ICD-10 diagnostic criteria, there is
evidence that while children with AS acquire language on time, their use of language may be atypical;
[5] "speech and language peculiarities" and "odd speech" are included in other diagnostic schemes.
[23][19] Individuals with AS may demonstrate abnormal speech and language, including pedantic
speech; oddities in pitch, intonation, prosody, and rhythm; literal interpretations and
miscomprehension of nuance; a lack of sensitivity or an inability to use language in social contexts
(for example, interrupting others or inserting irrelevant commentary and inappropriate personal
remarks); unusually formal or idiosyncratic speech; verbosity, speech reflecting the idiosyncratic
interests of the speaker or the use of metaphors meaningful only to the individual; selective mutism;
and auditory discrimination issues, particularly when multiple people are speaking simultaneously.[2]
According to Klin, at least three aspects of these individuals' communication patterns are of clinical
interest: poor prosody, tangential and circumstantial speech, and marked verbosity.[6] 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 overly fast, jerky or loud. Speech may convey a sense of
incoherence; although some of these cases may be symptomatic of a thought disorder, there is
often a conversational style that includes monologues about topics of little or no interest the
listener, a failure to provide context or background for comments, and a failure to suppress internal
thoughts. Individuals with AS may talk incessantly about a favorite topic, and may fail to monitor
whether the listener is interested or engaged in the conversation. The conclusion or point of long-
winded monologues may never be made, and attempts by the listener to elaborate on the content or
logic of the exchange, or to shift the focus to related topics, are often unsuccessful.[6]
Children with AS may have an unusually sophisticated vocabulary at a young age (and have been
colloquially referred to as "little professors") but have difficulty understanding metaphorical language
and tend to use language literally.[5][38] Autism researcher Tony Attwood gives the example of a
girl with AS who answered the telephone and was asked, "Is Paul there?" Although Paul was in the
house, he was not in the room with her, so she said "no" and hung up. The caller had to call back
and explain that he meant for her to find Paul and have him pick up the telephone.[39] Individuals
with AS appear to have particular weaknesses in several areas of nonliteral language, including
humor, irony and teasing.[11] A study analyzing adolescents’ responses to cartoons found that
individuals with AS and HFA had difficulty comprehending humor.[40] Another study of young adults
with AS found they understood ironic jokes less readily than typical controls and were poor at using
social context to interpret conversational meaning;[41] people with AS usually understand the
cognitive basis of humor, but may lack understanding of the intent of humor—to "share enjoyment
with others".[11]
Other
Problems with motor skills are not part of the DSM-IV diagnostic criteria, but Asperger’s initial
accounts[5] and other diagnostic schemes[19] include descriptions of motor clumsiness. Children
with AS may be delayed in acquiring motor skills that require motor dexterity, such as bicycle riding
or opening a jar, and may appear awkward or "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, visual–perceptual skills, and conceptual learning,[6][5] while having "relative
strengths in auditory and verbal skills and rote learning".[6] Research also shows problems with
proprioception and "deficits on measures of apraxia, balance tandem gait, and finger–thumb
apposition".[42] There is no evidence that these motor skills problems differentiate AS from other
high-functioning ASDs.[5]
Children with AS may be sensitive to sound (hyperacusis), touch, taste, sight, smell, pain,
temperature, and the texture of foods; they may exhibit synesthesia,[2] a neurologically based
phenomenon in which the stimulation of one sensory or cognitive pathway leads to automatic,
involuntary experiences in a second sensory or cognitive pathway. A review of all controlled
investigations published since 1960 showed that sensory symptoms were more frequent in children
with autism, but there was little support for hyperarousal or habituation in autism; there was
evidence of hyporesponsiveness to sensory stimuli, although many of these findings have not been
replicated.[43]
According to McPartland and Klin (2006), a unique neuropsychological profile has been described for
AS and confirmed in a review of the literature;[44] if verified, it could differentiate between AS and
HFA and aid in differential diagnosis. Relative to HFA, people with AS have deficits in "fine and gross
motor skills; visual motor integration; visual-spatial perception; nonverbal concept formation; and
visual memory with preserved articulation, verbal output, auditory perception, vocabulary, and verbal
memory".[45] Verbal abilities are stronger than performance abilities and indicate weakness in visual–
spatial organization and graphomotor skills.[46] Most subjects with AS in another study had a
"neuropsychologic profile consistent with a nonverbal learning disability".[47] The literature review did
not reveal consistent findings of "nonverbal weaknesses or increased spatial or motor problems
relative to individuals with HFA", leading some researchers to argue that increased cognitive ability is
evidenced in AS relative to HFA regardless of differences in verbal and nonverbal ability.[48]
Alexithymia is a personality trait of people who have difficulty recognizing, processing and regulating
emotions.[49] Uta Frith reported that alexithymia overlaps with AS, and that at least half of the
Asperger syndrome subjects in a study obtained scores that indicate severe impairment.[50] Other
researchers concur that both conditions are characterized by core disturbances in speech and
language and social relationships[51][52] and the limbic system and prefrontal cortex may be
involved in both.[4][53] Alexithymic traits in AS may be linked to depression or anxiety;[50] the
mediating factors are unknown and it is possible that alexithymia predisposes a person to anxiety.
[53]
Diagnosis of Asperger syndrome
Asperger's Disorder is defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV)
by six main criteria.[23]
The ICD-10 criteria are almost identical to DSM-IV:[54] ICD-10 adds the statement that motor
clumsiness is usual (although not necessarily a diagnostic feature); ICD-10 adds the statement that
isolated special skills, often related to abnormal preoccupations, are common but are not required for
diagnosis; and the DSM-IV requirement for clinically significant impairment in social, occupational, or
other important areas of functioning is not included in ICD-10.[55][4]
The DSM-IV and ICD-10 diagnostic criteria have been criticized for being too broad and inadequate
for assessing adults,[56] overly narrow (particularly in relation to Hans Asperger's original
description of individuals with AS),[13][54] and vague;[19] results of a large study in 2007
comparing the four sets of criteria point to a "huge need to reconsider the diagnostic criteria of AS."
[55] The study found complete overlap across all sets of diagnostic criteria in the impairment of
social interaction with the exception of four cases not diagnosed by the Szatmari et al. criteria
because of its emphasis on social solitariness. Lack of overlap was strongest in the language delay
and odd speech requirements of the Gillberg and the Szatmari requirements relative to DSM-IV and
ICD-10, in the differing requirements regarding general delays, and in DSM's requirement for
impairment.[55]
Signs suggestive of AS are often noted by a general practitioner or pediatrician during a routine
developmental check up. The National Institute of Neurological Disorders and Stroke advise that this
be followed up with a comprehensive team evaluation to either confirm or exclude a diagnosis of AS.
[5] Foster and King state that the determination of whether there is a family history of autism
spectrum conditions can be important.[57] Fitzgerald states that a multidisciplinary team approach
can be critical to avoiding misdiagnosis;:[54] an accurate assessment of the individual's strengths
and weaknesses is claimed to be more useful than a diagnostic label.[5] Delayed or mistaken
diagnosis is regarded as a serious problem that can be traumatic for individuals and families;
diagnosis based solely on a neurological, speech and language, or educational attainment may yield
only a partial diagnosis.[54]
It has been found that parents of children with AS can typically trace differences in their children's
development to as early as 30 months of age, although diagnosis is not made on average until the
age of 11.[57] By definition, children with AS develop language and self-help skills on schedule, so
early signs may not be apparent and the condition may not be diagnosed until later childhood.
Impairment in social interaction is sometimes not in evidence until a child attains an age at which
these behaviors become important; social disabilities are often first noticed when children encounter
peers in daycare or preschool.[5] Diagnosis is most commonly made between the ages of four and
eleven, and one study suggests that diagnosis cannot be rendered reliably before age four.[5]
Asperger syndrome can be misdiagnosed as a number of other conditions, leading to medications
that are unnecessary or even worsen behavior.[54]
Causes of autism
Asperger described common symptoms among his patients' family members, especially fathers,[5]
and research supports this observation and suggests a genetic contribution to AS.[5][57] 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.[57] 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).[1] Most research suggests that all autism
spectrum disorders have shared genetic mechanisms, but AS may have a stronger genetic
component than autism.[5] 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.[1] No gene has been
identified for AS, although studies suggest specific genetic abnormalities: such as various types of
chromosomal translocations in chromosomes 1, 5, 11, 13, 14, 15 and 17; autosomal fragile site,
fragile X syndrome, fragile Y, and 21pþ.[5] Anomalies in chromosome 22 were related to the
diagnosis of autism and Asperger syndrome in five children. The distal tip of the long arm of the
chromosome 22 contains the SHANK3 gene, which is thought to have a role in the maturation and
maintenance of brain synapses. The deletion of this part of the chromosome (22q13 deletion
syndrome) was found in low-functioning autistic subjects, and its duplication observed in a subject
diagnosed with Asperger syndrome.[58]
Environmental factors may interact with genetic influences to play a role in the cause of ASDs, but
research has identified no consistent correlations.[5] There is strong evidence that genetic factors
play a major role in the causes of autism spectrum disorders, while none of the possible
environmental causes has been confirmed by scientific investigation.[59]
Mechanism
Brain imaging techniques have revealed structural and functional differences in specific regions of the
brains of AS children; these are most likely caused by the abnormal migration of embryonic cells
during fetal development, which affects the final structure and connectivity of the brain, resulting in
alterations in the neural circuits that control thought and behavior.[1] Although progress has been
made, brain imaging technologies have failed to identify the specific underpinnings of AS or factors
that distinguish it from other ASDs and no clear pathology common to individuals with AS has
emerged.[5] Functional MRI has provided interesting findings, but no convincing evidence
reproducibly indicates differences among AS and other ASDs.[5]
One study reported a reduction of brain activity in the frontal lobe of AS children when they were
asked to respond to tasks that required them to use their judgment. These differences in activity
were also seen when children were asked to respond to facial expressions.[1] Another study, of
brain function in adults with AS, revealed abnormal levels of some proteins and demonstrated a
correlation between these levels and obsessive and repetitive behaviors.[1] Possible differences in
AS include:[5] gray tissue anomalies,[60][61] left temporal lobe damage,[62] and left occipital
hypoperfusion.[63] Other possible causative mechanisms include serotonin dysfunction and
cerebellar dysfunction.[64][65] Differences in brain volumes—such as enlarged amygdala and
hippocampus—have been linked to autism;[66] the most robust findings are of the reduced size of
the corpus callosum and rapid brain growth and increased brain volume in early childhood that
normalizes in mid-childhood.[67] Other research suggests abnormal right hemisphere functioning in
AS,[68] dysfunction in brain regions affecting social cognition,[69] and problems with functional
connectivity among separate brain regions.[70]
Simon Baron-Cohen proposes a model for Asperger's[71] that extends the extreme male brain
theory, which hypothesizes that autism is an extreme case of the male brain, defined psycho-
metrically as individuals in whom systemizing is better than empathizing.[72] Hyper-systemizing
hypothesizes that autistic individuals can systematize—that is, they can develop internal rules of
operation to handle internal events—but are less effective at empathizing by handling events
generated by other agents.[73] This in turn is related to the earlier theory of mind, which
hypothesizes that autistic behavior arises from an inability to ascribe mental states to oneself and
others.[74] Two studies showed that Asperger subjects had a second-order theory of mind;
compared to younger or more impaired autistic individuals, they were able to understand problems
of the type "Peter thinks that Jane thinks that ..." although their explanationns of their solutions did
not use mental states.[75] There is some evidence that the mind-reading capacity of children in the
higher-functioning range of the autistic spectrum are intact.[76]
Autism therapies
The goal of treatment is the development of age-appropriate social, communication and vocational
abilities, and the successful management of distressing symptoms, aiming to teach through explicit
instruction the skills that are not naturally acquired during development.[5] Intervention should be
tailored to the needs of the individual child, based on multidisciplinary assessment.[77] Although
progress has been made, data supporting the efficacy of particular interventions are limited.[5]
The ideal treatment for AS coordinates therapies that address the three core symptoms of the
disorder: poor communication skills, obsessive or repetitive routines, and physical clumsiness. While
most professionals agree that the earlier the intervention, the better, there is no single best
treatment package.[1] 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.[5] A typical treatment program generally includes:[1]
* the training of social skills for more effective interpersonal interactions;
* cognitive behavioral therapy to improve the management of anxiety or explosive emotions, and to
reduce the prevalence of obsessive interests and repetitive routines;
* medication, for coexisting conditions such as depression and anxiety;
* occupational or physical therapy to assist with poor sensory integration and motor coordination;
* specialized speech therapy, to help with the pragmatics of the "give and take" of normal
conversation;
* the training and support of parents, particularly in behavioral techniques to use in the home.
There have been many studies on psychologically based early intervention programs; most of these
are case studies of up to five participants.[78] These studies typically examine non-core autistic
problem behaviors such as self-injury, aggression, noncompliance, stereotypies and spontaneous
language.[78] Despite the widespread application of social skills training, its effectiveness is not
firmly established.[79] A randomized controlled study of a model for training parents in problem
behaviors in their children with AS showed that parents attending a 1-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.[80] 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.[5]
No medications specifically target AS[4] or directly treat the core symptoms of autism spectrum
disorders; research into the efficacy of pharmaceutical intervention for AS is limited.[5] However, it is
essential to diagnose and treat comorbid conditions;[4] medication can be effective in combination
with behavioral interventions and environmental accommodations in treating comorbid symptoms
such as anxiety, depression, inattention and aggression.[5] The atypical neuroleptic medications
risperidone and olanzapine have been shown to reduce the associated symptoms of AS;[5]
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
repetitive behaviors and restricted interests.[4][57][5]
Care must be taken in the management of pharmacotherapy; abnormalities in metabolism, cardiac
conduction times, and an increased risk of type 2 diabetes have been raised as concerns with these
medications[81][82] and unintended side effects have largely been ignored in the literature.[78]
SSRIs can lead to manifestations of behavioral activation such as increased impulsivity, aggression
and sleep disturbance.[57] 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[57] and increased serum prolactin levels.[83] Sedation and weight gain are more
common with olanzapine,[82] which has also been linked with diabetes.[81] Sedative side-effects in
school-age children[84] 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.[12]
Prognosis
As of 2006, no studies addressing the long-term outcome of individuals with AS are available and
there are no systematic long-term follow-up studies of children with AS.[6] Individuals with AS
appear to have normal life expectancy but have an increased prevalence of comorbid psychiatric
conditions such as depression, mood disorders, and obsessive-compulsive disorder that may
significantly affect prognosis. Although the social impairment is believed to be lifelong,[2] outcome is
generally more positive than with individuals with lower functioning autism spectrum disorders.[5][90]
Children with AS are vulnerable to being teased and victimized; some may require special education
services because of their social and behavioral difficulties although many attend regular education
classes.[6] Adolescents with AS may exhibit ongoing difficulty with self-care, organization and
disturbances in social and romantic relationships;[91] despite high cognitive potential, most remain
at home, although some do marry and work independently.[5][92] The "different-ness" adolescents
experience can be traumatic.[24] Although the deficits associated with AS are often debilitating,
many individuals experience positive outcomes—particularly those who are able to excel in areas less
dependent on social interaction, such as mathematics, music, and the sciences. Reports suggest
that many people with AS are highly creative and accomplish innovative research in fields such as
computer science, mathematics, and physics.[2] Baron-Cohen reports a link between AS and high-
achieving mathematicians, physicists and computer scientists that shows that the condition need not
be an obstacle to achievement.[93] The symptoms of AS can at some point "fade to normal" and
people with AS can become valued workers as adults because of the "intensity of interest and
volume of knowledge" that they may bring to idiosyncratic subjects,[24] but they may lose
employment if impaired understanding of social norms leads to poor judgment in work site behavior.
[2]
Education of families is critical in developing strategies for understanding strengths and weaknesses;
[4] prognosis is improved when individuals with AS have supportive families who are knowledgeable
about Asperger's.[2] Prognosis may be improved by diagnosis at a younger age that allows for early
interventions, while interventions in adulthood are valuable but less beneficial.[4] 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.[4] The hypothesis that the combination of
intact intellectual and linguistic ability with limited empathy and social understanding may predispose
individuals with AS to violent or criminal behavior has been investigated and found to be
unsupported by data.[5][94]
Epidemiology
The incidence of AS is not well established, but conservative estimates using the DSM-IV criteria
indicate that two to three of every 10,000 children have the condition, making it rarer than autistic
disorder itself.[1][95] A computerized registry in Denmark indicates an annual incidence of 1.4 per
10,000 for AS.[4] Advocacy and parent support organizations have proliferated around the concept
of AS, and there are indications that this has resulted in more frequent diagnoses of AS, which may
be given as a "residual diagnosis" to children of normal intelligence who do not meet diagnostic
criteria for autism but have some social difficulties.[6]
A 2003 review of epidemiological studies[96] found prevalence rates ranging from .03 to 4.8 per
1,000; the authors suggested a working rate of .26 per 1,000.[5] A 1993 Sweden study found the
prevalence of AS was 3.6 per 1,000 among school-aged children aged 7–16 using Gillberg's criteria,
rising to 7.1 per 1,000 if suspected cases are included.[19] The estimate is convincing for Sweden,
but the findings may not apply elsewhere because they are based on a homogeneous population.[2]
Prevalence estimates vary according to the diagnostic criteria employed. An epidemiological study of
5,484 eight-year-old children in Finland found 2.9 children per 1,000 met the ICD-10 criteria for an
AS diagnosis, 2.7 per 1,000 for Gillberg and Gillberg criteria, 2.5 for DSM-IV and 1.6 for Szatmari et
al. The number of children diagnosed as having AS according to any of the four criteria was 4.3 per
1,000.[55] Leekam et al. documented significant differences between Gillberg's criteria and the ICD-
10 criteria.[97]
Like other autism spectrum disorders, AS prevalence estimates for males are higher than for females.
[1] The Sweden study found a 4:1 male to female ratio in subjects meeting Gillberg's criteria for AS,
but a lower 2.3:1 ratio when suspected or borderline cases were included.[19] The Finland study
found a "somewhat surprising" male-to-female ratio according to DSM-IV criteria of 0.8:1; Gillberg
and Gillberg criteria yielded a 2:1 ratio and the ratio when including children diagnosed per any of the
four sets of diagnostic criteria was 1.7:1. Females with AS may not be recognized in studies as they
tend to be superficially more sociable than boys, although closer examination reveals problems in
social interaction.[55]
Comorbidities
Most patients presenting in clinical settings with AS have other comorbid psychiatric disorders;
children are likely to present with attention-deficit hyperactivity disorder (ADHD), while depression is
a common diagnosis in adolescents and adults.[98] Many children with AS are initially misdiagnosed
with ADHD.[5] Individuals with AS may also be diagnosed with oppositional defiant disorder,
antisocial personality disorder, tic disorders and Tourette syndrome, general anxiety disorder, bipolar
disorder, obsessive compulsive disorder or obsessive-compulsive personality disorder.[99]
The conditions most commonly seen are depression and anxiety; comorbidity of these in persons
with AS is estimated at 65%. Anxiety may stem from preoccupation over possible violations of
routines and rituals or result from being placed in a situation without a clear schedule or
expectations. Social anxiety (concern with failing in social encounters) may also manifest. Depression
is often the result of chronic frustration from repeated failure to engage others socially, and mood
disorders requiring treatment may develop.[5]
The particularly high comorbidity with anxiety often requires special attention; one study reported
that about 84% of individuals with a pervasive developmental disorder also met the criteria for
anxiety disorder.[100] Because of the social differences experienced by those with AS, such as
trouble initiating or maintaining a conversation or adherence to strict rituals or schedules, additional
stress to any of these activities may result in feelings of anxiety, which can negatively affect multiple
areas of one's life, including school, family, and work. Anxiety disorders can be treated with
medication or individual and group cognitive behavioral therapy, where relaxation or distraction-type
activities may be used along with other techniques to diffuse the feelings of anxiety.[101]
Psychosocial factors may contribute to poor adjustment or psychiatric issues. An Internet survey of
middle-class mothers of children with AS and nonverbal learning disorders found peer and sibling
victimization of the children was common; 94% of mothers reported peer victimization of their
children. According to the mothers, in the year leading up to the study, almost three-quarters of the
children had been hit by peers or siblings and 75% had been emotionally bullied. More seriously,
10% of the children were attacked by a gang and 15% were victims of nonsexual assaults to the
genitals. Many of the children ate alone at lunch or were picked last for sports teams, and a third had
not been invited to a birthday party in the past year.[102]
Reports have associated AS with medical conditions such as aminoaciduria and ligamentous laxity,
but these have been case reports or small studies and no factors have been associated with AS
across studies.[5] An increased rate of epilepsy is reported in individuals with AS, and there is a high
rate (51%) of non-verbal learning disability.[103]
* References provided upon request.
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