Asperger's
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Asperger syndrome (AS), also known as Asperger's, is a former
neurodevelopmental disorder Neurodevelopmental disorders are a group of disorders that affect the development of the nervous system, leading to abnormal brain function which may affect emotion, learning ability, self-control, and memory. The effects of neurodevelopmenta ...
characterized by significant difficulties in
social interaction A social relation or also described as a social interaction or social experience is the fundamental unit of analysis within the social sciences, and describes any voluntary or involuntary interpersonal relationship between two or more individuals ...
and
nonverbal communication Nonverbal communication (NVC) is the transmission of messages or signals through a nonverbal platform such as eye contact, facial expressions, gestures, posture, and body language. It includes the use of social cues, kinesics, distance ( pr ...
, along with restricted and repetitive patterns of behaviour and interests. The syndrome is no longer recognised as a diagnosis in itself, having been merged with other disorders into
autism spectrum disorder The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...
(ASD). It was considered to differ from other diagnoses that were merged into ASD by relatively unimpaired
spoken language A spoken language is a language produced by articulate sounds or (depending on one's definition) manual gestures, as opposed to a written language. An oral language or vocal language is a language produced with the vocal tract in contrast with a si ...
and
intelligence Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. More generally, it can ...
. The syndrome was named after the Austrian
pediatrician Pediatrics ( also spelled ''paediatrics'' or ''pædiatrics'') is the branch of medicine that involves the medical care of infants, children, adolescents, and young adults. In the United Kingdom, paediatrics covers many of their youth until the ...
Hans Asperger Johann Friedrich Karl Asperger (, ; 18 February 1906 – 21 October 1980) was an Austrian psychiatrist. He is remembered for his pioneering studies of autism, specifically in children. His name was given to Asperger syndrome, a form of autism ...
, who, in 1944, described children in his care who struggled to form friendships, did not understand others'
gestures A gesture is a form of non-verbal communication or non-vocal communication in which visible bodily actions communicate particular messages, either in place of, or in conjunction with, speech. Gestures include movement of the hands, face, o ...
or
feelings Feelings are subjective self-contained phenomenal experiences. According to the ''APA Dictionary of Psychology'', a feeling is "a self-contained phenomenal experience"; and feelings are "subjective, evaluative, and independent of the sensations ...
, engaged in one-sided conversations about their favourite interests, and were clumsy. In 1994, the diagnosis of Asperger's was included in the fourth edition (DSM-IV) of the American ''
Diagnostic and Statistical Manual of Mental Disorders The ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM; latest edition: DSM-5-TR, published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a common langu ...
''; with the publication of DSM-5 in 2013 the diagnosis was removed, and the symptoms are now included within autism spectrum disorder along with
classic autism Kanner autism, or classic autism, is an outdated neurodevelopmental diagnosis which is now considered part of autism spectrum disorder. The term 'autism' was historically used to refer specifically to classic autism, but it is now the most popu ...
and
pervasive developmental disorder not otherwise specified A pervasive developmental disorder not otherwise specified (Including atypical autism) (PDD-NOS) is one of four disorders which were collapsed into the diagnosis of autism spectrum disorder in the DSM-5 and also was one of the five disorders cla ...
(PDD-NOS). It was similarly merged into autism spectrum disorder in the
International Classification of Diseases The International Classification of Diseases (ICD) is a globally used diagnostic tool for epidemiology, health management and clinical purposes. The ICD is maintained by the World Health Organization (WHO), which is the directing and coordinating ...
(
ICD-11 The ICD-11 is the eleventh revision of the International Classification of Diseases (ICD). It replaces the ICD-10 as the global standard for recording health information and causes of death. The ICD is developed and annually updated by the World H ...
) . The exact cause of Asperger's is poorly understood. While it has high heritability, the underlying
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar work ...
have not been determined conclusively. Environmental factors are also believed to play a role.
Brain imaging Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Incre ...
has not identified a common underlying condition. There is no single treatment, and the UK's
National Health Service The National Health Service (NHS) is the umbrella term for the publicly funded healthcare systems of the United Kingdom (UK). Since 1948, they have been funded out of general taxation. There are three systems which are referred to using the " ...
(NHS) guidelines suggest that 'treatment' of any form of autism should not be a goal, since autism is not 'a disease that can be removed or cured'. According to the
Royal College of Psychiatrists The Royal College of Psychiatrists is the main professional organisation of psychiatrists in the United Kingdom, and is responsible for representing psychiatrists, for psychiatric research and for providing public information about mental healt ...
, while co-occurring conditions might require treatment, 'management of autism itself is chiefly about the provision of the education, training and social support/care required to improve the person's ability to function in the everyday world'. The effectiveness of particular interventions for autism is supported by only limited data. Interventions may include social skills training,
cognitive behavioral therapy Cognitive behavioral therapy (CBT) is a psycho-social intervention that aims to reduce symptoms of various mental health conditions, primarily depression and anxiety disorders. CBT focuses on challenging and changing cognitive distortions (suc ...
,
physical therapy Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, pat ...
,
speech therapy Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are th ...
, parent training, and medications for associated problems, such as mood or anxiety. NIH Publication No. 05-5624. Autistic characteristics tend to become less obvious in adulthood, but social and communication difficulties usually persist. In 2015, Asperger's was estimated to affect 37.2 million people globally, or about 0.5% of the population. The exact percentage of people affected is not firmly established. Autism spectrum disorder is diagnosed in males more often than females, and females are typically diagnosed at a later age. The modern conception of Asperger syndrome came into existence in 1981, and went through a period of popularization. It became a standardized
diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine "cause and effect". In systems engin ...
in the 1990s, and was retired as a diagnosis in 2013. Many questions and controversies about the condition remain.


Classification

The extent of the overlap between Asperger syndrome and high-functioning autism ( HFA – autism unaccompanied by
intellectual disability Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation, Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signif ...
) is unclear. The ASD classification is to some extent an artifact of how autism was discovered, and may not reflect the true nature of the spectrum; methodological problems have beset Asperger syndrome as a valid diagnosis from the outset. In the fifth edition of the ''
Diagnostic and Statistical Manual of Mental Disorders The ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM; latest edition: DSM-5-TR, published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a common langu ...
'' (DSM-5), published in May 2013, Asperger syndrome, as a separate diagnosis, was eliminated and folded into autism spectrum disorder. Like the diagnosis of Asperger syndrome, the change was controversial and thus Asperger syndrome was subsequently not removed from the WHO's
ICD-10 ICD-10 is the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD), a medical classification list by the World Health Organization (WHO). It contains codes for diseases, signs and symptoms ...
; however, it was removed from the
ICD-11 The ICD-11 is the eleventh revision of the International Classification of Diseases (ICD). It replaces the ICD-10 as the global standard for recording health information and causes of death. The ICD is developed and annually updated by the World H ...
. The
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...
(WHO) previously defined Asperger syndrome (AS) as one of the
autism spectrum disorder The autism spectrum, often referred to as just autism or in the context of a professional diagnosis autism spectrum disorder (ASD) or autism spectrum condition (ASC), is a neurodevelopmental condition (or conditions) characterized by difficulti ...
s (ASD) or
pervasive developmental disorder The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), is a group of disorders characterized by delays in the development of multiple basic functions including socialization and ...
s (PDD), which are a spectrum of psychological conditions that are characterized by abnormalities of
social interaction A social relation or also described as a social interaction or social experience is the fundamental unit of analysis within the social sciences, and describes any voluntary or involuntary interpersonal relationship between two or more individuals ...
and communication that pervade the individual's functioning, and by restricted and repetitive interests and behavior. Like other neurodevelopment 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 In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (biology), morphology or physical form and structure, its Developmental biology, developmental proc ...
, which describes individuals who may not have ASD but do have autistic-like traits, such as social deficits.


Characteristics

As a
pervasive developmental disorder The diagnostic category pervasive developmental disorders (PDD), as opposed to specific developmental disorders (SDD), is a group of disorders characterized by delays in the development of multiple basic functions including socialization and ...
, 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. Suicidal behavior appears to occur at rates similar to those without ASD.


Social interaction

A lack of ''demonstrated''
empathy Empathy is the capacity to understand or feel what another person is experiencing from within their frame of reference, that is, the capacity to place oneself in another's position. Definitions of empathy encompass a broad range of social, co ...
affects aspects of social relatability for persons with Asperger syndrome. Individuals with Asperger syndrome 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 (e.g., showing others objects of interest); a lack of social or emotional reciprocity; and impaired nonverbal behaviors in areas such as
eye contact Eye contact occurs when two people look at each other's eyes at the same time. In humans, eye contact is a form of nonverbal communication and can have a large influence on social behavior. Coined in the early to mid-1960s, the term came from ...
,
facial expression A facial expression is one or more motions or positions of the muscles beneath the skin of the face. According to one set of controversial theories, these movements convey the emotional state of an individual to observers. Facial expressions are ...
, posture, and gesture. People with Asperger syndrome may not be as withdrawn around others, compared with those with other forms of autism; they approach others, even if awkwardly. For example, a person with Asperger syndrome may engage in a one-sided, long-winded speech about a favorite topic, while misunderstanding or not recognizing the listener's
feelings Feelings are subjective self-contained phenomenal experiences. According to the ''APA Dictionary of Psychology'', a feeling is "a self-contained phenomenal experience"; and feelings are "subjective, evaluative, and independent of the sensations ...
or reactions, such as a wish to change the topic of talk or end the interaction. This social awkwardness has been called "active but odd". Such failures to react appropriately to social interaction may appear as disregard for other people's feelings and may come across as rude or insensitive. However, not all individuals with Asperger syndrome will approach others. Some may even display selective mutism, not speaking at all to most people and excessively to specific others. Some may choose only to talk to people they like. The cognitive ability of children with AS often allows them to articulate
social norms Social norms are shared standards of acceptable behavior by groups. Social norms can both be informal understandings that govern the behavior of members of a society, as well as be codified into rules and laws. Social normative influences or soci ...
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 observations 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 naïve. Childhood desire for companionship can become numbed through a history of failed social encounters.


Violent or criminal behavior

The
hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...
that individuals with AS are predisposed to violent or criminal behavior has been investigated but is not supported by data. More evidence suggests that children diagnosed with Asperger syndrome are more likely to be victims, rather than offenders. A 2008 review found that an overwhelming number of reported violent criminals with Asperger syndrome also had other coexisting psychotic
psychiatric disorders A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitt ...
such as
schizoaffective disorder Schizoaffective disorder (SZA, SZD or SAD) is a mental disorder characterized by abnormal thought processes and an unstable mood. This diagnosis is made when the person has symptoms of both schizophrenia (usually psychosis) and a mood disorder: ...
. This coexistence of psychotic disorders is referred to as comorbid disorders. Comorbid disorders can be completely independent of one another or can have overlap in symptoms and how they express themselves.


Empathy

People with an Asperger profile might not be recognized for their empathetic qualities, due to variation in the ways
empathy Empathy is the capacity to understand or feel what another person is experiencing from within their frame of reference, that is, the capacity to place oneself in another's position. Definitions of empathy encompass a broad range of social, co ...
is felt and expressed. Some people feel deep empathy, but do not outwardly communicate these sentiments through facial expressions or language. Some people come to empathy through intellectual processes, using logic and reasoning to arrive at the feelings. It is also important to keep in mind that many people with Asperger profiles have been bullied or excluded by peers in the past and might therefore be guarded around people, which could appear as lack of empathy. People with Asperger profiles can be and are extremely caring individuals; in fact, it is particularly common for those with the profile to feel and exhibit deep concern for human welfare, animal rights, environmental protection, and other global and humanitarian causes. Evidence suggests that in the "double empathy problem model, autistic people have a unique interaction style which is significantly more readable by other autistic people, compared to non-autistic people."


Restricted and repetitive interests and behavior

People with Asperger syndrome can 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 In social psychology, a stereotype is a generalized belief about a particular category of people. It is an expectation that people might have about every person of a particular group. The type of expectation can vary; it can be, for example ...
and repetitive ways, preoccupy themselves with parts of objects, or engage in compulsive behaviors like lining objects up to form patterns. The pursuit of specific and narrow areas of interest is one of the most striking among possible features of AS. Individuals with AS may collect volumes of detailed information on a relatively narrow topic such as weather data or star names without necessarily having a 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 age five or six. 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 Flapping or tapping, also known as alveolar flapping, intervocalic flapping, or ''t''-voicing, is a phonological process found in many varieties of English, especially North American, Cardiff, Ulster, Australian and New Zealand English, whereby ...
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. However, in addition to this, various studies have reported a consistent comorbidity between AS and
Tourette syndrome Tourette syndrome or Tourette's syndrome (abbreviated as TS or Tourette's) is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) ...
in the range of 8–20%, with one figure as high as 80% for tics of some kind or another, for which several explanations have been put forward, including common genetic factors and
dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% o ...
,
glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can synt ...
, or
serotonin Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and va ...
abnormalities. According to the Adult Asperger Assessment (AAA) diagnostic test, a lack of interest in fiction and a positive preference towards non-fiction is common among adults with AS.


Speech and language

Although individuals with Asperger syndrome acquire language skills without significant general delay and their speech typically lacks significant abnormalities,
language acquisition Language acquisition is the process by which humans acquire the capacity to perceive and comprehend language (in other words, gain the ability to be aware of language and to understand it), as well as to produce and use words and sentences to ...
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 An idiosyncrasy is an unusual feature of a person (though there are also other uses, see below). It can also mean an odd habit. The term is often used to express eccentricity or peculiarity. A synonym may be "quirk". Etymology The term "idiosyncr ...
speech; and oddities in loudness, pitch, intonation, prosody, and rhythm.
Echolalia Echolalia is the unsolicited repetition of vocalizations made by another person (when repeated by the same person, it is called palilalia). In its profound form it is automatic and effortless. It is one of the echophenomena, closely related t ...
has also been observed in individuals with AS. Three aspects of communication patterns are of clinical interest: poor prosody, tangential and
circumstantial speech Circumstantial speech, also referred to as circumstantiality, is the result of a so-called "non-linear thought pattern" and occurs when the focus of a conversation drifts, but often comes back to the point.''Problem-Based Psychiatry'' by Ben Green 2 ...
, and marked verbosity. Although
inflection In linguistic morphology, inflection (or inflexion) is a process of word formation in which a word is modified to express different grammatical categories such as tense, case, voice, aspect, person, number, gender, mood, animacy, and ...
and intonation may be less rigid or monotonic than in classic 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 Context may refer to: * Context (language use), the relevant constraints of the communicative situation that influence language use, language variation, and discourse summary Computing * Context (computing), the virtual environment required to s ...
for comments, or fails to suppress internal thoughts. Individuals with AS may fail to detect 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 a sophisticated vocabulary at a young age and such children have often been colloquially called "little professors" but have difficulty understanding
figurative language Literal and figurative language is a distinction within some fields of language analysis, in particular stylistics, rhetoric, and semantics. *Literal language uses words exactly according to their conventionally accepted meanings or denotat ...
and tend to use language literally. Children with AS appear to have particular weaknesses in areas of nonliteral language that include
humor Humour (Commonwealth English) or humor (American English) is the tendency of experiences to provoke laughter and provide amusement. The term derives from the humoral medicine of the ancient Greeks, which taught that the balance of fluids in ...
,
irony Irony (), in its broadest sense, is the juxtaposition of what on the surface appears to be the case and what is actually the case or to be expected; it is an important rhetorical device and literary technique. Irony can be categorized int ...
,
teasing Teasing has multiple meanings and uses. In human interactions, teasing exists in three major forms: ''playful'', ''hurtful'', and ''educative''. Teasing can have a variety of effects, depending on how it is used and its intended effect. When teas ...
, and
sarcasm Sarcasm is the caustic use of words, often in a humorous way, to mock someone or something. Sarcasm may employ ambivalence, although it is not necessarily ironic. Most noticeable in spoken word, sarcasm is mainly distinguished by the inflection ...
. Although individuals with AS usually understand the cognitive basis of humor, they seem to lack understanding of the intent of humor to share the 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.


Motor and sensory perception

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 Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum ref ...
. 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 with individuals with
high-functioning autism High-functioning autism (HFA) is an autism classification where a person exhibits no intellectual disability, but may exhibit deficits in communication, emotion recognition and expression, and social interaction. HFA is not included in either t ...
, individuals with AS have deficits in some tasks involving visual-spatial perception, auditory perception, or
visual memory Visual memory describes the relationship between perceptual processing and the encoding, storage and retrieval of the resulting neural representations. Visual memory occurs over a broad time range spanning from eye movements to years in order ...
. 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, and other stimuli; 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 The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first des ...
or failure of
habituation Habituation is a form of non-associative learning in which an innate (non-reinforced) response to a stimulus decreases after repeated or prolonged presentations of that stimulus. Responses that habituate include those that involve the intact org ...
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
dexterity Fine motor skill (or dexterity) is the coordination of small muscles in movement with the eyes, hands and fingers. The complex levels of manual dexterity that humans exhibit can be related to the nervous system. Fine motor skills aid in the growt ...
, 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
motor coordination Motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each body part involved in ...
. They may show problems with
proprioception Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons ...
(sensation of body position) on measures of
developmental coordination disorder Developmental coordination disorder (DCD), also known as developmental motor coordination disorder, developmental dyspraxia or simply dyspraxia from the word 'praxis' meaning to do or act, is a neurodevelopmental disorder characterized by impaire ...
(
motor planning In psychology and neuroscience Neuroscience is the science, scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a Multidisciplinary approach, multidisciplinary scien ...
disorder), balance, tandem gait, and finger-
thumb apposition The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...
. 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 Middle-of-the-night insomnia (MOTN) is characterized by having difficulty returning to sleep after waking up during the night or very early in the morning. This kind of insomnia (sleeplessness) is different from initial or sleep-onset insomnia, wh ...
, and early morning awakenings. AS is also associated with high levels of
alexithymia Alexithymia is a personality trait characterized by the inability to identify and describe emotions experienced by oneself. The core characteristic of alexithymia is marked dysfunction in emotional awareness, social attachment, and interpersonal ...
, which is difficulty in identifying and describing one's emotions. Although AS, lower sleep quality, and alexithymia are associated with each other, their causal relationship is unclear.


Causes

Hans Asperger described common traits among his patients' family members, especially fathers, and research supports this observation and suggests a genetic contribution to Asperger syndrome. Although no specific genetic factor has yet been identified, multiple factors are believed to play a role in the
expression Expression may refer to: Linguistics * Expression (linguistics), a word, phrase, or sentence * Fixed expression, a form of words with a specific meaning * Idiom, a type of fixed expression * Metaphorical expression, a particular word, phrase, o ...
of autism, given the variability in symptoms seen in children. Evidence for a genetic link is that AS tends to run in families where more family members have limited behavioral symptoms similar to AS (for example, some problems with social interaction, or with language and reading skills). Most behavioral genetic research suggests that all autism spectrum disorders have shared genetic mechanisms, but AS may have a stronger genetic component than autism. There may be shared genes in which particular
allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chrom ...
s make an individual vulnerable, and varying combinations result in differing severity and symptoms in each person with AS. A few ASD cases have been linked to exposure to
teratogens Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related ...
(agents that cause
birth defect A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...
s) 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 ASD arises very early in development. Many
environmental factor An environmental factor, ecological factor or eco factor is any factor, abiotic or biotic, that influences living organisms. Abiotic factors include ambient temperature, amount of sunlight, and pH of the water soil in which an organism lives. Bi ...
s have been hypothesized to act after birth, but none has been confirmed by scientific investigation.


Mechanism

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 ASDs.
Neuroanatomical Neuroanatomy is the study of the structure and organization of the nervous system. In contrast to animals with radial symmetry, whose nervous system consists of a distributed network of cells, animals with bilateral symmetry have segregated, defi ...
studies and the associations with
teratogens Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related ...
strongly suggest that the mechanism includes alteration of brain development soon after conception. Abnormal
fetal development Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...
may affect the final structure and connectivity of the brain, resulting in altered neural circuits controlling thought and behavior. Several theories of mechanism are available; none are likely to provide a complete explanation.


General-processing theories

One general-processing theory is 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 Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...
operations in autistic individuals.


Mirror neuron system (MNS) theory

The mirror neuron system (MNS) theory hypothesizes that alterations to the development of the MNS interfere with
imitation Imitation (from Latin ''imitatio'', "a copying, imitation") is a behavior whereby an individual observes and replicates another's behavior. Imitation is also a form of that leads to the "development of traditions, and ultimately our culture. I ...
and lead to Asperger's core feature of social impairment. One study found that activation is delayed in the core circuit for imitation in individuals with AS. This theory maps well to
social cognition Social cognition is a sub-topic of various branches of psychology that focuses on how people process, store, and apply information about other people and social situations. It focuses on the role that cognitive processes play in social interacti ...
theories like the
theory of mind In psychology, theory of mind refers to the capacity to understand other people by ascribing mental states to them (that is, surmising what is happening in their mind). This includes the knowledge that others' mental states may be different fro ...
, 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 Empathy is the capacity to understand or feel what another person is experiencing from within their frame of reference, that is, the capacity to place oneself in another's position. Definitions of empathy encompass a broad range of social, cog ...
when handling events generated by other agents.


Diagnosis

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, the DSM-IV-TR criteria also required significant impairment in day-to-day functioning; DSM-5 eliminated AS as a separate diagnosis in 2013, and folded it into the umbrella of autism spectrum disorders. Other sets of diagnostic criteria have been proposed by Peter Szatmari#Diagnostic criteria for Asperger Syndrome, Szatmari ''et al.'' and by Christopher Gillberg#Gillberg's criteria for Asperger syndrome, 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 "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. Underdiagnosis and overdiagnosis may be problems. The cost and difficulty of Screening (medicine), screening and assessment can 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 are not autistic but have social difficulties. 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 or PDD-NOS; different screening tools may render different diagnoses for the same person.


Differential diagnosis

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 along with ADHD include other ASDs, the schizophrenia spectrum, personality disorders, obsessive–compulsive disorder, major depressive disorder, semantic pragmatic disorder, nonverbal learning disorder, social anxiety disorder,
Tourette syndrome Tourette syndrome or Tourette's syndrome (abbreviated as TS or Tourette's) is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) ...
, stereotypic movement disorder, bipolar disorder, social-cognitive deficits due to brain damage from alcohol use disorder, and obsessive–compulsive personality disorder (OCPD).


Screening

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 United States Preventive Services Task Force in 2016 found it was unclear if screening was beneficial or harmful among children in whom there are no concerns. Different screening instruments are used to diagnose AS, including the Asperger Syndrome Diagnostic Scale (ASDS); Autism Spectrum Screening Questionnaire (ASSQ); Childhood Autism Spectrum Test (CAST), previously called the Childhood Asperger Syndrome Test; 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.


Management

Treatment attempts to manage distressing symptoms and to teach age-appropriate social, communication, and vocational skills that are not naturally acquired during development. Intervention is tailored to the needs of the individual based on multidisciplinary assessment. Although progress has been made, data supporting the efficacy of particular interventions are limited.


Therapies

Managing AS ideally involves multiple therapies that address core symptoms of the disorder. While most professionals agree that the earlier the intervention, the better, there is no treatment combination that is recommended above others. 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: * Applied behavior analysis (ABA) procedures, including positive behavior support (PBS)—or training and support of parents and school faculty in behavior management strategies to use in the home and school, and social skills training for more effective interpersonal interactions; * Cognitive behavioral therapy to improve stress management relating to anxiety or explosive emotions and to help reduce obsessive interests and repetitive routines; * Medication for coexisting conditions such as major depressive disorder and anxiety disorders; * Occupational therapy, Occupational or
physical therapy Physical therapy (PT), also known as physiotherapy, is one of the allied health professions. It is provided by physical therapists who promote, maintain, or restore health through physical examination, diagnosis, management, prognosis, pat ...
to assist with poor sensory processing and
motor coordination Motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each body part involved in ...
; and, * Social communication intervention, which is specialized speech therapy to help with the pragmatics and give-and-take of normal conversation. Of the many studies on behavior-based early intervention programs, most are case reports 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 can improve the work and life management of people with AS.


Medications

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 disorders, major depressive disorder, inattention, and aggression. The atypical antipsychotic medications risperidone, olanzapine and aripiprazole 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, while stimulant medication, such as methylphenidate, can reduce inattention. Care must be taken with medications, as side effects may be more common and harder to evaluate in individuals with AS, and tests of drugs' effectiveness against comorbid conditions routinely exclude individuals from the autism spectrum. Abnormalities in metabolism, Electrical conduction system of the heart, cardiac conduction times, and an increased risk of Diabetes mellitus type 2, type 2 diabetes have been raised as concerns with antipsychotic medications, along with serious long-term neurological side effects. SSRIs 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 Mood (psychology), moods and emotions or to tolerate side effects that for most people would not be problematic.


Prognosis

There is some evidence that children with AS may see a lessening of symptoms; up to 20% of children may no longer meet the diagnostic criteria as adults, although social and communication difficulties may persist. , 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 disorders that may significantly affect prognosis. Although social impairment may be lifelong, the 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. Most students with AS and HFA have average mathematical ability and test slightly worse in mathematics than in general intelligence. However, mathematicians are at least three times more likely to have autism-spectrum traits than the general population, and are more likely to have family members with autism. Although many attend regular education classes, some children with AS may attend special education classes such as separate classroom and resource room because of their social and behavioral difficulties. Adolescents with AS may exhibit ongoing difficulty with self-care or organization, and disturbances in social and romantic relationships. Despite high cognitive potential, most young adults with AS remain at home, yet 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 Social anxiety, concern with failing in social encounters; the resulting Stress (psychological), 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.


Epidemiology

Frequency estimates vary enormously. In 2015, it was estimated that 37.2 million people globally are affected. A 2003 review of epidemiological studies of children found autism rates ranging from 0.03 to 4.84 per 1,000, with the ratio of autism to Asperger syndrome ranging from 1.5:1 to 16:1; combining the geometric mean ratio of 5:1 with a conservative prevalence estimate for autism of 1.3 per 1,000 suggests indirectly that the prevalence of AS might be around 0.26 per 1,000. Part of the variance in estimates arises from Diagnosis of Asperger syndrome#Multiple sets of diagnostic criteria, differences in diagnostic criteria. For example, a relatively small 2007 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, 1.6 for Szatmari ''et al.'', and 4.3 per 1,000 for the union of the four criteria. Boys seem to be more likely to have AS than girls; estimates of the sex ratio range from 1.6:1 to 4:1, using the Gillberg and Gillberg criteria. Females with autism spectrum disorders may be underdiagnosed.


Comorbidities

Anxiety disorders and major depressive disorder are the most common conditions seen at the same time; comorbidity of these in persons with AS is estimated at 65%. 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. One study of males with AS found an increased rate of epilepsy and a high rate (51%) of nonverbal learning disorder. AS is associated with tics,
Tourette syndrome Tourette syndrome or Tourette's syndrome (abbreviated as TS or Tourette's) is a common neurodevelopmental disorder that begins in childhood or adolescence. It is characterized by multiple movement (motor) tics and at least one vocal (phonic) ...
and bipolar disorder. The repetitive behaviors of AS have many similarities with the symptoms of obsessive–compulsive disorder and obsessive–compulsive personality disorder, and 26% of a sample of young adults with AS were found to meet the criteria for schizoid personality disorder (which is characterised by severe social seclusion and emotional detachment), more than any other personality disorder in the sample. However many of these studies are based on sampling bias, clinical samples or lack standardized measures; nonetheless, comorbid conditions are relatively common.


History

Named after the Austrian pediatrician
Hans Asperger Johann Friedrich Karl Asperger (, ; 18 February 1906 – 21 October 1980) was an Austrian psychiatrist. He is remembered for his pioneering studies of autism, specifically in children. His name was given to Asperger syndrome, a form of autism ...
(1906–1980), Asperger syndrome is a relatively new diagnosis in the field of autism, though a syndrome like it was described as early as 1925 by Soviet child psychiatrist Grunya Sukhareva (1891–1981), leading some of those diagnosed with Asperger's Syndrome to instead refer to their condition as 'Sukhareva's Syndrome', in opposition to Hans Asperger's association with Nazism. As a child, Asperger appears to have exhibited some features of the very condition named after him, such as remoteness and talent in language. In 1944, Asperger described four children in his practice who had difficulty in integrating themselves socially and showing empathy towards peers. They also lacked nonverbal communication skills and were physically clumsy. Asperger described this "autistic psychopathy" as social isolation. Fifty years later, several standardizations of AS as a medical diagnosis were tentatively proposed, many of which diverge significantly from Asperger's original work. Unlike today's AS, autistic psychopathy could be found in people of all levels of intelligence, including those with intellectual disability. Asperger defended the value of so-called "high-functioning" autistic individuals, writing: "We are convinced, then, that autistic people have their place in the organism of the social community. They fulfill their role well, perhaps better than anyone else could, and we are talking of people who as children had the greatest difficulties and caused untold worries to their care-givers." Asperger also believed some would be capable of exceptional achievement and original thought later in life. Asperger's paper was published during World War II and in German, so it was not widely read elsewhere. Lorna Wing used the term ''Asperger syndrome'' in 1976, and popularized it to the English-speaking medical community in her February 1981 publication of case studies of children showing the symptoms described by Asperger, and Uta Frith translated his paper to English in 1991. Sets of diagnostic criteria were outlined by Gillberg and Gillberg in 1989 and by Szatmari ''et al.'' in the same year. In 1992, AS became a standard diagnosis when it was included in the tenth edition of the
World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level o ...
's diagnostic manual, ''International Classification of Diseases'' (
ICD-10 ICD-10 is the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD), a medical classification list by the World Health Organization (WHO). It contains codes for diseases, signs and symptoms ...
). It was added to the fourth edition of the American Psychiatric Association's diagnostic reference, ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM-IV), published in 1994. Hundreds of books, articles, and websites now describe AS and prevalence estimates have increased dramatically for ASD, with AS recognized as an important subgroup. Whether it should be seen as distinct from high-functioning autism is a fundamental issue requiring further study, and there are questions about the empirical validation of the DSM-IV and ICD-10 criteria. In 2013, DSM-5 eliminated AS as a separate diagnosis, folding it into the autism spectrum on a severity scale.


Society and culture

People identifying with Asperger syndrome may refer to themselves in casual conversation as ''aspies'' (a term first used in print in the ''The Boston Globe, Boston Globe'' in 1998). Some autistic people have advocated a shift in perception of autism spectrum disorders as complex syndromes rather than diseases that must be cured. Proponents of this view reject the notion that there is an "ideal" brain configuration and that any deviation from the norm is pathological; they promote tolerance for what they call neurodiversity. These views are the basis for the autistic rights and autistic pride movements. There is a contrast between the attitude of adults with self-identified AS, who typically do not want to be cured and are proud of their identity; and parents of children with AS, who typically seek assistance and a cure for their children. Some researchers have argued that AS can be viewed as a different cognitive style, not a disorder, and that it should be removed from the standard ''Diagnostic and Statistical Manual'', much as homosexuality was removed. In a 2002 paper, Simon Baron-Cohen wrote of those with AS: "In the social world, there is no great benefit to a precise eye for detail, but in the worlds of maths, computing, cataloging, music, linguistics, engineering, and science, such an eye for detail can lead to success rather than failure." Baron-Cohen cited two reasons why it might still be useful to consider AS to be a disability: to ensure provision for legally required special support, and to recognize emotional difficulties from reduced empathy. A preliminary, freely readable draft, with slightly different wording in the quoted text, is in: Baron-Cohen argues that the genes for Asperger's combination of abilities have operated throughout recent human evolution and have made remarkable contributions to human history. By contrast, Pier Jaarsma and Welin wrote in 2011 that the "broad version of the neurodiversity claim, covering low-functioning as well as high-functioning autism, is problematic. Only a narrow conception of neurodiversity, referring exclusively to high-functioning autists, is reasonable." They say that "higher functioning" individuals with autism may "not [be] benefited with such a psychiatric defect-based diagnosis ... some of them are being harmed by it, because of the disrespect the diagnosis displays for their natural way of being", but "think that it is still reasonable to include other categories of autism in the psychiatric diagnostics. The narrow conception of the neurodiversity claim should be accepted but the broader claim should not." Jonathan Mitchell (writer), Jonathan Mitchell, an autistic disorder, autistic author and blogger who advocates a cure for autism, has described autism as having "prevented me from making a living or ever having a girlfriend. It's given me bad fine motor coordination problems where I can hardly write. I have an impaired ability to relate to people. I can't concentrate or get things done." He describes neurodiversity as a "tempting escape valve".


References


Further reading

* Autistic Empire
Are you Autistic? Take the test
– an online version of the Adult Asperger's Assessment developed by Cohen, S. et al. (2005) (see Woodbury-Smith MR, "Screening adults for Asperger Syndrome using the AQ: a preliminary study of its diagnostic validity in clinical practice", in #References, §References). * A public paper re-calibrating the Autism Diagnostic Observation Schedule for appropriate assessment of autistic adults, who typically score lower on measures of impairment than autistic children due to compensatory strategies. * Royal College of Psychiatrists (2017)
Interview Guide for the Diagnostic Assessment of Able Adults with Autistic Spectrum Disorder
– based on the Autism Diagnostic Interview-Revised (ADI-R) {{Authority control Asperger syndrome, Autism, * Autism spectrum disorders, * 1976 neologisms Genetic disorders by system Learning disabilities Neurological disorders Neurological disorders in children Wikipedia medicine articles ready to translate Wikipedia neurology articles ready to translate