Asperger syndrome (AS) is characterized by impairments in social interaction and restricted interests and behaviors as seen in autism, but its early developmental course is marked by a lack of any clinically significant delay in spoken or receptive language, cognitive development, self-help skills, and curiosity about the environment. All-absorbing and intense circumscribed interests and one-sided verbosity as well motor clumsiness are typical of the condition, but are not required for diagnosis.
1. History and nosology—
In 1944, Hans Asperger, an Austrian pediatrician with interest in special education, described four kids who had difficulty integrating socially into groups.19 Unaware of Kanner's description of early infantile autism published just the year before, Asperger called the condition he described "autistic psychopathy", indicating a stable personality disorder marked by social isolation. Despite preserved intellectual skills, the kids showed marked paucity of nonverbal communication involving both gestures and affective tone of voice, poor empathy and a tendency to intellectualize emotions, an inclination to engage in long winded, one-sided, and sometimes incoherent speech, rather formalistic speech (he called them "little professors"), all-absorbing interests involving unusual topics which dominated their conversation, and motoric clumsiness. Unlike Kanner's patients, these kids were not as withdrawn or aloof; they also developed, sometimes precociously, highly grammatical speech, and could not in fact be diagnosed in the first years of life. Discarding the possibility of a psychogenic origin, Asperger highlighted the familial nature of the condition, and even hypothesized that the personality traits were primarily male transmitted. Aspergers work, originally published in German, became widely known to the English speaking world only in 1981, when Lorna Wing published a series of cases showing similar symptoms.20 Her codification of the syndrome, however, blurred somewhat the differences between Kanner's and Aspergers descriptions, as she included a small number of girls and mildly mentally retarded kids, as well as some kids who had presented with some language delays in their first years of life. Since then, several studies have attempted to validate ASPERGERS as distinct from autism without mental retardation, although comparability of findings has been difficult due to the lack of consensual diagnostic criteria for the condition.3
ASPERGERS was not accorded official recognition before the publication of ICD-10 and DSM-IV, although it was first reported in the German literature in 1944. Aspergers work was known primarily in German speaking countries, and it was only in the 1970's that the first comparisons with Kanner's work were made, primarily by Dutch researchers such as Van Krevelen, who were familiar with both English and German literatures. The initial attempts at comparing the two conditions were difficult because of major differences in the patients described - Kanner's patients were both younger and more cognitively impaired. Also, Aspergers conceptualization was influenced by accounts of schizophrenia and personality disorders, whereas Kanner had been influenced by the work of Arnold Gesell and his developmental approach. Attempts at codifying Aspergers prose into a categorical definition for the condition were made by several influential researchers in Europe and North America, but no consensual definition emerged until the advent of ICD-10. And given the reduced empirical validation of the ICD-10 and DSM-IV criteria, the definition of the condition is likely to change as new and more rigorous studies emerge in the near future.21
2. Epidemiology—
Given the lack of consensual definitions of diagnosis until recently, it is not surprising that the prevalence of the condition is unknown, although a rate of 2 to 4 in 10,000 has been reported.22 There is little doubt that the condition is more prevalent in males than females, with a reported ratio of 9 to 1. In the past few years, there have been a proliferation of parent support organizations organized around the concept of ASPERGERS, and there are indications that this diagnosis is being given by clinicians much more frequently than even just a few years ago; there are also indications that ASPERGERS is currently functioning as a residual diagnosis given to normal-intelligence kids with a degree of social disabilities who do not fulfill criteria for autism, overlapping in this way, with the DSM-IV term PDD-NOS. Possibly the most common usage of the term ASPERGERS is as synonymous or a replacement to autism in children with normative or superior IQs. This pattern has diluted the concept and reduced its clinical utility. Empirical validation of specific diagnostic criteria is badly needed, although this will have to await reports of rigorous studies employing standard diagnostic procedures, and validators truly independent of the diagnostic definition such as neuropsychological, neurobiological and genetic data.3
3. Diagnosis and clinical features—
The diagnosis of ASPERGERS requires the demonstration of qualitative impairments in social interaction and restricted patterns of interest, criteria which are identical to autism. In contrast to autism, there are no criteria in the cluster of language and communication symptoms, and onset criteria differ in that there should be no clinically significant delay in language acquisition, cognitive and self-help skills. Those symptoms result in significant impairment in social and occupational functioning.9
In some contrast to the social presentation in autism, children with ASPERGERS find themselves socially isolated but are not usually withdrawn in the presence of others. Typically, they approach others but in an inappropriate or eccentric fashion. For example, they may engage the interlocutor, usually an adult, in one-sided conversation characterized by long-winded, pedantic speech, about a favorite and often unusual and narrow topic. They may express interest in friendships and in meeting people, but their wishes are invariably thwarted by their awkward approaches and insensitivity to the other person's feelings, intentions, and non-literal and implied communications (e.g., signs of boredom, haste to leave, and need for privacy). Chronically frustrated by their repeated failures to engage others and form friendships, some children with ASPERGERS develop symptoms of an anxiety or mood disorder that may require treatment, including medication. They also may react inappropriately to, or fail to interpret the valence of the context of the affective interaction, often conveying a sense of insensitivity, formality, or disregard to the other person's emotional expressions. They may be able to describe correctly, in a cognitive and often formalistic fashion, other people's emotions, expected intentions and social conventions; yet, they are unable to act upon this knowledge in an intuitive and spontaneous fashion, thus losing the tempo of the interaction. Their poor intuition and lack of spontaneous adaptation are accompanied by marked reliance on formalistic rules of behavior and rigid social conventions. This presentation is largely responsible for the impression of social naiveté and behavioral rigidity that is so forcefully conveyed by these children.
Although significant abnormalities of speech are not typical of children with ASPERGERS, there are at least three aspects of these children' communication patterns that are of clinical interest.21 First, speech may be marked by poor prosody, although inflection and intonation may not be as rigid and monotonic as in autism. They often exhibit a constricted range of intonation patterns that is used with little regard to the communicative functioning of the utterance (e.g., assertions of fact, humorous remarks). Rate of speech may be unusual (e.g., too fast) or may lack in fluency (e.g., jerky speech), and there is often poor modulation of volume (e.g., voice is too loud despite physical proximity to the conversational partner). The latter feature may be particularly noticeable in the context of a lack of adjustment to the given social setting (e.g., in a library, in a noisy crowd). Second, speech may often be tangential and circumstantial, conveying a sense of looseness of associations and incoherence. Even though in a very small number of cases this symptom may be an indicator of a possible thought disorder, the lack of contingency in speech is a result of the one-sided, egocentric conversational style (e.g., unrelenting monologues about the names, codes, and attributes of innumerable TV stations in the country), failure to provide the background for comments and to clearly demarcate changes in topic, and failure to suppress the vocal output accompanying internal thoughts. Third, the communication style of children with ASPERGERS is often characterized by marked verbosity. The youngster or adult may talk incessantly, usually about a favorite subject, often in complete disregard to whether the listener might be interested, engaged, or attempting to interject a comment, or change the subject of conversation. Despite such long-winded monologues, the individual may never come to a point or conclusion. Attempts by the interlocutor to elaborate on issues of content or logic, or to shift the interchange to related topics, are often unsuccessful.
Children with ASPERGERS typically amass a large amount of factual information about a topic in a very intense fashion. The actual topic may change from time to time, but often dominates the content of social interchange. Frequently the entire family may be immersed in the subject for long periods of time. This behavior is peculiar in the sense that oftentimes extraordinary amounts of factual information are learned about very circumscribed topics (e.g., snakes, names of stars, TV guides, deep fat fryers, weather information, personal information on members of congress) without a genuine understanding of the broader phenomena involved. This symptom may not always be easily recognized in childhood since strong interests in certain topics, such as dinosaurs or fashionable fictional characters, are so ubiquitous. However, in both younger and older kids typically the special interests become more unusual and narrowly focused.
Children with ASPERGERS may have a history of delayed acquisition of motor skills such as pedaling a bike, catching a ball, opening jars, and climbing outdoor play equipment. They are often visibly awkward and poorly coordinated and may exhibited stilted or bouncy gait patterns and odd posture. Neuropsychologically, there is often a pattern of relative strengths in auditory and verbal skills and rote learning, and significant deficits in visual-motor and visual-perceptual skills and conceptual learning. Many kids exhibit high levels of activity in early childhood, and, as noted, may develop anxiety and depression in adolescence and young adulthood.
4. Course and prognosis—
There are no systematic long-term follow-up studies of kids with ASPERGERS as yet, partially because of nosologic issues. Many kids are able to attend regular education classes with additional support services, although these kids are especially vulnerable to being seen as eccentric and of being teased or victimized; others require special education services, usually not because of academic deficits but because of their social and behavioral difficulties. Aspergers initial description predicted a positive outcome for many of his patients, who were often able to utilize their special talents for the purpose of obtaining employment and leading self-supporting lives. His observation of similar traits in family members, i.e., fathers, may also have made him more optimistic about ultimate outcome. Although his account was tempered somewhat by the time he had seen 200 patients with the syndrome (25 years after his original paper), Asperger continued to believe that a more positive outcome was a central criterion differentiating children with his syndrome from those with Kanner's autism. Although some clinicians have informally concurred with this statement, particularly in regards to gainful employment, independence, and establishment of a family, no studies specially addressing the long-term outcome of children with ASPERGERS is currently available. The social impairment (particularly the eccentricities and social insensitivity), is thought to be lifelong.
Summary—
Autism and Asperger syndrome are syndromes resulting from early-emerging and fundamental disruptions in the socialization process leading to a cascade of developmental impacts on social engagement and adaptation, communication and imagination, among other disabilities. Many areas of cognitive functioning are often preserved, and sometimes children with these conditions exhibit surprising if not prodigious skills. The early onset, symptom profile, and chronicity of these conditions implicate core biological mechanisms.23 Advancements in genetics, neurobiology and neuroimaging (described elsewhere in this supplement), are concurrently furthering our understanding of the nature of these conditions and of the formation of the social brain in typical children.24 Together with the new wave of prospective studies of autism,25 where siblings at risk for developing the condition are followed up from birth, a new social neuroscience perspective on the pathogenesis and pathobiology of factors is emerging. This effort is likely to elucidate the mysteries of the etiology and the pathogenesis of these conditions. Translational research into more efficacious treatment, if not prevention, will then hopefully follow.
1. History and nosology—
In 1944, Hans Asperger, an Austrian pediatrician with interest in special education, described four kids who had difficulty integrating socially into groups.19 Unaware of Kanner's description of early infantile autism published just the year before, Asperger called the condition he described "autistic psychopathy", indicating a stable personality disorder marked by social isolation. Despite preserved intellectual skills, the kids showed marked paucity of nonverbal communication involving both gestures and affective tone of voice, poor empathy and a tendency to intellectualize emotions, an inclination to engage in long winded, one-sided, and sometimes incoherent speech, rather formalistic speech (he called them "little professors"), all-absorbing interests involving unusual topics which dominated their conversation, and motoric clumsiness. Unlike Kanner's patients, these kids were not as withdrawn or aloof; they also developed, sometimes precociously, highly grammatical speech, and could not in fact be diagnosed in the first years of life. Discarding the possibility of a psychogenic origin, Asperger highlighted the familial nature of the condition, and even hypothesized that the personality traits were primarily male transmitted. Aspergers work, originally published in German, became widely known to the English speaking world only in 1981, when Lorna Wing published a series of cases showing similar symptoms.20 Her codification of the syndrome, however, blurred somewhat the differences between Kanner's and Aspergers descriptions, as she included a small number of girls and mildly mentally retarded kids, as well as some kids who had presented with some language delays in their first years of life. Since then, several studies have attempted to validate ASPERGERS as distinct from autism without mental retardation, although comparability of findings has been difficult due to the lack of consensual diagnostic criteria for the condition.3
ASPERGERS was not accorded official recognition before the publication of ICD-10 and DSM-IV, although it was first reported in the German literature in 1944. Aspergers work was known primarily in German speaking countries, and it was only in the 1970's that the first comparisons with Kanner's work were made, primarily by Dutch researchers such as Van Krevelen, who were familiar with both English and German literatures. The initial attempts at comparing the two conditions were difficult because of major differences in the patients described - Kanner's patients were both younger and more cognitively impaired. Also, Aspergers conceptualization was influenced by accounts of schizophrenia and personality disorders, whereas Kanner had been influenced by the work of Arnold Gesell and his developmental approach. Attempts at codifying Aspergers prose into a categorical definition for the condition were made by several influential researchers in Europe and North America, but no consensual definition emerged until the advent of ICD-10. And given the reduced empirical validation of the ICD-10 and DSM-IV criteria, the definition of the condition is likely to change as new and more rigorous studies emerge in the near future.21
2. Epidemiology—
Given the lack of consensual definitions of diagnosis until recently, it is not surprising that the prevalence of the condition is unknown, although a rate of 2 to 4 in 10,000 has been reported.22 There is little doubt that the condition is more prevalent in males than females, with a reported ratio of 9 to 1. In the past few years, there have been a proliferation of parent support organizations organized around the concept of ASPERGERS, and there are indications that this diagnosis is being given by clinicians much more frequently than even just a few years ago; there are also indications that ASPERGERS is currently functioning as a residual diagnosis given to normal-intelligence kids with a degree of social disabilities who do not fulfill criteria for autism, overlapping in this way, with the DSM-IV term PDD-NOS. Possibly the most common usage of the term ASPERGERS is as synonymous or a replacement to autism in children with normative or superior IQs. This pattern has diluted the concept and reduced its clinical utility. Empirical validation of specific diagnostic criteria is badly needed, although this will have to await reports of rigorous studies employing standard diagnostic procedures, and validators truly independent of the diagnostic definition such as neuropsychological, neurobiological and genetic data.3
3. Diagnosis and clinical features—
The diagnosis of ASPERGERS requires the demonstration of qualitative impairments in social interaction and restricted patterns of interest, criteria which are identical to autism. In contrast to autism, there are no criteria in the cluster of language and communication symptoms, and onset criteria differ in that there should be no clinically significant delay in language acquisition, cognitive and self-help skills. Those symptoms result in significant impairment in social and occupational functioning.9
In some contrast to the social presentation in autism, children with ASPERGERS find themselves socially isolated but are not usually withdrawn in the presence of others. Typically, they approach others but in an inappropriate or eccentric fashion. For example, they may engage the interlocutor, usually an adult, in one-sided conversation characterized by long-winded, pedantic speech, about a favorite and often unusual and narrow topic. They may express interest in friendships and in meeting people, but their wishes are invariably thwarted by their awkward approaches and insensitivity to the other person's feelings, intentions, and non-literal and implied communications (e.g., signs of boredom, haste to leave, and need for privacy). Chronically frustrated by their repeated failures to engage others and form friendships, some children with ASPERGERS develop symptoms of an anxiety or mood disorder that may require treatment, including medication. They also may react inappropriately to, or fail to interpret the valence of the context of the affective interaction, often conveying a sense of insensitivity, formality, or disregard to the other person's emotional expressions. They may be able to describe correctly, in a cognitive and often formalistic fashion, other people's emotions, expected intentions and social conventions; yet, they are unable to act upon this knowledge in an intuitive and spontaneous fashion, thus losing the tempo of the interaction. Their poor intuition and lack of spontaneous adaptation are accompanied by marked reliance on formalistic rules of behavior and rigid social conventions. This presentation is largely responsible for the impression of social naiveté and behavioral rigidity that is so forcefully conveyed by these children.
Although significant abnormalities of speech are not typical of children with ASPERGERS, there are at least three aspects of these children' communication patterns that are of clinical interest.21 First, speech may be marked by poor prosody, although inflection and intonation may not be as rigid and monotonic as in autism. They often exhibit a constricted range of intonation patterns that is used with little regard to the communicative functioning of the utterance (e.g., assertions of fact, humorous remarks). Rate of speech may be unusual (e.g., too fast) or may lack in fluency (e.g., jerky speech), and there is often poor modulation of volume (e.g., voice is too loud despite physical proximity to the conversational partner). The latter feature may be particularly noticeable in the context of a lack of adjustment to the given social setting (e.g., in a library, in a noisy crowd). Second, speech may often be tangential and circumstantial, conveying a sense of looseness of associations and incoherence. Even though in a very small number of cases this symptom may be an indicator of a possible thought disorder, the lack of contingency in speech is a result of the one-sided, egocentric conversational style (e.g., unrelenting monologues about the names, codes, and attributes of innumerable TV stations in the country), failure to provide the background for comments and to clearly demarcate changes in topic, and failure to suppress the vocal output accompanying internal thoughts. Third, the communication style of children with ASPERGERS is often characterized by marked verbosity. The youngster or adult may talk incessantly, usually about a favorite subject, often in complete disregard to whether the listener might be interested, engaged, or attempting to interject a comment, or change the subject of conversation. Despite such long-winded monologues, the individual may never come to a point or conclusion. Attempts by the interlocutor to elaborate on issues of content or logic, or to shift the interchange to related topics, are often unsuccessful.
Children with ASPERGERS typically amass a large amount of factual information about a topic in a very intense fashion. The actual topic may change from time to time, but often dominates the content of social interchange. Frequently the entire family may be immersed in the subject for long periods of time. This behavior is peculiar in the sense that oftentimes extraordinary amounts of factual information are learned about very circumscribed topics (e.g., snakes, names of stars, TV guides, deep fat fryers, weather information, personal information on members of congress) without a genuine understanding of the broader phenomena involved. This symptom may not always be easily recognized in childhood since strong interests in certain topics, such as dinosaurs or fashionable fictional characters, are so ubiquitous. However, in both younger and older kids typically the special interests become more unusual and narrowly focused.
Children with ASPERGERS may have a history of delayed acquisition of motor skills such as pedaling a bike, catching a ball, opening jars, and climbing outdoor play equipment. They are often visibly awkward and poorly coordinated and may exhibited stilted or bouncy gait patterns and odd posture. Neuropsychologically, there is often a pattern of relative strengths in auditory and verbal skills and rote learning, and significant deficits in visual-motor and visual-perceptual skills and conceptual learning. Many kids exhibit high levels of activity in early childhood, and, as noted, may develop anxiety and depression in adolescence and young adulthood.
4. Course and prognosis—
There are no systematic long-term follow-up studies of kids with ASPERGERS as yet, partially because of nosologic issues. Many kids are able to attend regular education classes with additional support services, although these kids are especially vulnerable to being seen as eccentric and of being teased or victimized; others require special education services, usually not because of academic deficits but because of their social and behavioral difficulties. Aspergers initial description predicted a positive outcome for many of his patients, who were often able to utilize their special talents for the purpose of obtaining employment and leading self-supporting lives. His observation of similar traits in family members, i.e., fathers, may also have made him more optimistic about ultimate outcome. Although his account was tempered somewhat by the time he had seen 200 patients with the syndrome (25 years after his original paper), Asperger continued to believe that a more positive outcome was a central criterion differentiating children with his syndrome from those with Kanner's autism. Although some clinicians have informally concurred with this statement, particularly in regards to gainful employment, independence, and establishment of a family, no studies specially addressing the long-term outcome of children with ASPERGERS is currently available. The social impairment (particularly the eccentricities and social insensitivity), is thought to be lifelong.
Summary—
Autism and Asperger syndrome are syndromes resulting from early-emerging and fundamental disruptions in the socialization process leading to a cascade of developmental impacts on social engagement and adaptation, communication and imagination, among other disabilities. Many areas of cognitive functioning are often preserved, and sometimes children with these conditions exhibit surprising if not prodigious skills. The early onset, symptom profile, and chronicity of these conditions implicate core biological mechanisms.23 Advancements in genetics, neurobiology and neuroimaging (described elsewhere in this supplement), are concurrently furthering our understanding of the nature of these conditions and of the formation of the social brain in typical children.24 Together with the new wave of prospective studies of autism,25 where siblings at risk for developing the condition are followed up from birth, a new social neuroscience perspective on the pathogenesis and pathobiology of factors is emerging. This effort is likely to elucidate the mysteries of the etiology and the pathogenesis of these conditions. Translational research into more efficacious treatment, if not prevention, will then hopefully follow.