Asperger syndrome: a clinical account
Lorna Wing, from the MRC Social Psychiatry Unit, Institute of Psychiatry, London
Synopsis - The clinical features, course, aetiology, epidemiology, differential diagnosis and management of Asperger syndrome are described. Classification is discussed and reasons are given for including the syndrome, together with early childhood autism, in a wider group of conditions which have, in common, impairment of development of social interaction, communication and imagination.
Introduction
The many patterns of abnormal behaviour that cause diagnostic confusion include one originally described by the Austrian psychiatrist, Hans Asperger (1944, 1968, 1979). The name he chose for this pattern was 'autistic psychopathy' using the latter word in the technical sense of an abnormality of personality. This has led to misunderstanding because of the popular tendency to equate psychopathy with sociopathic behaviour. For this reason, the neutral term Asperger syndrome is to be preferred and will be used here.
Not long before Asperger' s original paper on this subject appeared in 1944, Kanner (1943) published his first account of the syndrome he called early infantile autism. The two conditions are, in many ways, similar, and the argument still continues as to whether they are varieties of the same underlying abnormality or are separate entities.
Whereas Kanner's work is widely known internationally, Asperger's contribution is considerably less familiar outside the German literature. The only published discussions of the subject in English known to the present author are by Van Krevelen (1971), Isaev & Kagan (1974), Mnukbin & Isaev (1975) (translation from Russian), Wing (1976), Chick et al (1979), Wolff & Barlow (1979) and Wolff & Chick (1980). In addition, a book by Bosch in which autism and Asperger syndrome are compared, originally appearing in German in 1962, has been translated into English (Bosch, 1962). A paper given by Asperger in Switzerland in 1977 has appeared in an English version (Asperger, 1979). Robinson & Vitale (1954) and Adams (1973) gave clinical descriptions of children with behaviour resembling Asperger syndrome, but without referring to this diagnosis.
In the present paper the syndrome will be described, illustrated with case histories, and the differential diagnosis and classification discussed. The account is based on Asperger's descriptions and on 34 cases, ranging in age from 5 to 35 years, personally examined and diagnosed by the author. Of these, 19 had the history and clinical picture of the syndrome in more or less typical form and 15 showed many of the features at the time they were seen, though they did not all have the characteristic early history (see below). Six of those in the series were identified as a result of an epidemiological study of early childhood psychoses in the Camberwell area of south-east London (Wing & Gould, 1979). The rest were referred to the author for diagnosis - 11 by their parents, through the family doctor, two by head teachers and 15 by other psychiatrists.
The following general description includes all the most typical features. But, as with any psychiatric syndrome identifiable only from a pattern of observable behaviour, there are difficulties in determining which are essential for diagnosis. Variations occur from person to person and it is rare to find, in any one case, all the details listed below.
The clinical picture
Illustrative case histories based on those of children and adults seen by the present author are to be found in the Appendix. Throughout the paper, the numbers in parentheses refer to these histories.
Asperger's description of the syndrome
Asperger noted that the syndrome was very much more common in boys than in girls. He believed that it was never recognised in infancy and usually not before the third year of life or later. The following description is based on Asperger's accounts.
Speech
The child usually begins to speak at the age expected in normal children, whereas walking may be delayed. A full command of grammar is sooner or later acquired, but there may be difficulty in using pronouns correctly, with the substitution of the second or third for the first person forms (No. 1). The content of speech is abnormal, tending to be pedantic and often consisting of lengthy disquisitions on favourite subjects (No.2). Sometimes a word or phrase is repeated over and over again in a stereotyped fashion. The child or adult may invent some words. Subtle verbal jokes are not understood, though simple verbal humour may be appreciated.
Non-verbal communication
Non-verbal aspects of communication are also affected. There may be little facial expression except with strong emotions such as anger or misery. Vocal intonation tends to be monotonous and droning, or exaggerated. Gestures are limited, or else large and clumsy and inappropriate for the accompanying speech (No. 2). Comprehension of other people's expressions and gestures is poor and the person with Asperger syndrome may misinterpret or ignore such non-verbal signs. At times he may earnestly gaze into another person's face, searching for the meaning that eludes him.
Social interaction
Perhaps the most obvious characteristic is impairment of two-way social interaction. This is not due primarily to a desire to withdraw from social contact. The problem arises from a lack of ability to understand and use the rules governing social behaviour. These rules are unwritten and unstated, complex, constantly changing, and affect speech, gesture, posture, movement, eye contact, choice of clothing, proximity to others, and many other aspects of behaviour. The degree of skill in this area varies among normal people, but those with Asperger syndrome are outside the normal range. Their social behaviour is naive and peculiar. They rnay be aware of their difficulties and even strive to overcome them, but in inappropriate ways and with signal lack of success. They do not have the intuitive knowledge of how to adapt their approaches and responses to fit in with the needs and personalities of others. Some are over-sensitive to criticism and suspicious of other people. A small minority have a history of rather bizarre antisocial acts, perhaps because of their lack of empathy. This was true of four of the present series, one of whom injured another boy in the course of his experiments on the properties of chemicals.
Relations with the opposite sex provide a good example of the more general social ineptitude. A young man with Asperger syndrome observes that most of his contemporaries have girl friends and eventually marry and have children. He wishes to be normal in this respect, but has no idea how to indicate his interest and attract a partner in a socially acceptable fashion. He may ask other people for a list of rules for talking to girls, or try to find the secret in books (No. 1). If he has a strong sex drive he may approach and touch or kiss a stranger, or someone much older or younger than himself, and, as a consequence, find himself in trouble with the police; or he may solve the problem by becoming solitary and withdrawn.
Repetitive activities and resistance to change
Children with this syndrome often enjoy spinning objects and watching them until the movement ceases, to a far greater extent than normal. They tend to become intensely attached to particular possessions and are very unhappy when away from familiar places.
Motor co-ordination
Gross motor movements are clumsy and ill-co-ordinated. Posture and gait appear odd (No.1). Most people with this syndrome (90% of the 34 cases mentioned above) are poor at games involving motor skills, and sometimes the executive problems affect the ability to write or to draw. Stereotyped movements of the body and limbs are also mentioned by Asperger.
Skills and interest
Those with the syndrome in most typical form have certain skills as well as impairments. They have excellent rote memories and become intensely interested in one or two subjects, such as astronomy, geology, the history of the steam train, the genealogy of royalty, bus time-tables, prehistoric monsters, or the characters in a television serial, to the exclusion of all else. They absorb every available fact concerning their chosen field and talk about it at length, whether or not the listener is interested, but have little grasp of the meaning of the facts they learn. They may also excel at board games needing a good rote memory, such as chess (No.2), and some have musical ability. Seventy-six per cent of the present author's series had special interests of this kind. However, some have specific learning problems, affecting arithmetical skills, reading, or, as mentioned above, writing.
Experiences at school
This combination of school and communication impairments, and certain special skills gives an impression of marked eccentricity. The children may be mercilessly bullied at school, becoming, in consequence, anxious and afraid (Nos. I and 2). Those who are more fortunate in the schools they attend may be accepted as eccentric 'professors', and respected for their unusual abilities (No.4). Asperger describes them as unsatisfactory students because they follow their own interests regardless of the teacher's instructions and the activities of the rest of the class (Nos. 3 and 4). Many eventually become aware that they are different from other people, especially as they approach adolescence, and, in consequence, become over-sensitive to criticism. They give the impression of fragile vulnerability and a pathetic childishness, which some find infinitely touching and others merely exasperating.
Modifications of Asperger's account
The present author has noted a number of additional items in the developmental history, not recorded by Asperger, which can sometimes be elicited by appropriate questioning of the parents. During the first year of life there may have been a lack of the normal interest and pleasure in human company that should be present from birth. Babbling may have been limited in quantity and quality. The child may not have drawn attention to things going on around him in order to share the interest with other people. He may not have brought his toys to show to his parents or visitors when he began to walk. In general, there is a lack of the intense urge to communicate in babble, gesture, movement, smiles, laughter and eventually speech that characterizes the normal baby and toddler (No.3).
Imaginative pretend play does not occur at all in some of those with the syndrome, and in those who do have pretend play it is confined to one or two themes, enacted without variation, over and over again. These may be quite elaborate, but are pursued repetitively and do not involve other children unless the latter are willing to follow exactly the same pattern. It sometimes happens that the themes seen in this pseudo-pretend play continue as preoccupations in adult life, and form the main focus of an imaginary world (see the case history of Richard L. in Bosch, 1962).
There are also two points on which the present author would disagree with Asperger's observations. First, he states that speech develops before walking, and refers to 'an especially intimate relationship with language' and 'highly sophisticated linguistic skills'. Van Krevelen (1971) emphasized this as a point of differentiation from Kanner's early childhood autism, in which, usually, walking develops normally, or even earlier than average, whereas the onset of speech is markedly delayed or never occurs. However, slightly less than half of the present author's more typical cases of Asperger syndrome were walking at the usual age, but were slow to talk. Half talked normally but were slow to walk, and one both walked and talked at the expected times. Despite the eventual good use of grammar and a large vocabulary, careful observation over a long enough period of time discloses that the content of speech is impoverished and much of it is copied inappropriately from other people or books (No.3). The language used gives the impression of being learned by rote. The meanings of long and obscure words may be known, but not those of words used every day (No.5). The peculiarities of non-verbal aspects of speech have already been mentioned.
Secondly, Asperger described people with his syndrome as capable of originality and creativity in their chosen field. It would be more true to say that their thought processes are confined to a narrow, pedantic, literal, but logical, chain of reasoning. The unusual quality of their approach arises from the tendency to select, as the starting point for the logical chain, some aspect of a subject that would be unlikely to occur to a normal person who has absorbed the attitudes current in his culture. Usually the result is inappropriate, but once in a while it gives new insight into a problem. Asperger also believed that people with his syndrome were of high intelligence, but he did not quote the results of standardized intellectual tests to support this. As will be seen from the case histories in the Appendix, the special abilities are based mainly on rote memory, while comprehension of the underlying meaning is poor. Those with the syndrome are conspicuously lacking in common sense.
It must be pointed out that the people described by the present author all had problems of adjustment or superimposed psychiatric illnesses severe enough to necessitate referral to a psychiatric clinic. Nine had left school or further education. Of these, three were employed, three had lost their jobs, and three had not obtained work. The author is also acquainted, through their parents who are members of The National Society for Autistic Children, with a few young adults reported to have some or all of the features of Asperger syndrome, and who are using their special skills successfully in open employment. It would be inappropriate to give precise numbers or to include these in the series, because the author does not have access to case histories or assessment. For this reason, the series described here is probably biased towards those with more severe handicaps.
Course and prognosis
The published clinical descriptions are of children and young adults. No studies of the course and prognosis in later life are available.
Asperger emphasized the stability of the clinical picture throughout childhood, adolescence and at least into early adult life, apart from the increase in skills brought about by maturation. The major characteristics appear to be impervious to the effects of environment and education. He considered the social prognosis to be generally good, meaning that most developed far enough to be able to use their special skills to obtain employment. He also observed that some who had especially high levels of ability in the area of their special interests were able to follow careers in, for example, science and mathematics.
As Bosch (1962) pointed out, it is possible to find people with all the features characteristic of Asperger syndrome other than normal or high intelligence. This applied to 20% of the series described here. If these are accepted as belonging to the same diagnostic category, then Asperger's rather hopeful view of the prognosis has to be modified to take such cases into account (see the case history of J.G., Appendix No.5).
The prognosis is also affected by the occurrence of superimposed psychiatric illnesses. Clinically diagnosable anxiety and varying degrees of depression may be found, especially in late adolescence or early adult life, which seem to be related to a painful awareness of handicap and difference from other people (Nos. 2 and 3). Wolff & Chick (1980), in a follow-up study of 22 people with Asperger syndrome, reported one who appeared to have a typical schizophrenic illness and another in whom this diagnosis was made, but less convincingly. Five of the 22 had attempted suicide by the time of early adult life.
The present author's series included 18 who were aged 16 and over at the time they were seen. Of these, four had an affective illness; four had become increasingly odd and withdrawn, probably with underlying depression; 1 had a psychosis with delusion and hallucinations that could not be classified; I had had an episode of catatonic stupor; one had bizarre behaviour and an unconfirmed diagnosis of schizophrenia; and two had bizarre behaviour, but no diagnosable psychiatric illness. Two of the foregoing had attempted suicide and one had talked of doing so. These two were referred because of their problems in coping with the demands of adult life.
Though it appears that the risk of psychiatric illness in Asperger syndrome is high, it is difficult to draw firm conclusions because of the nature of the samples that were studied. The 13 people mentioned above, before they were seen by the present author, had been referred to adult services because of superimposed psychiatric conditions, so the series was highly biased. Wolff's cases were somewhat less selective since they were referred as children and followed up into adult life, but, even so, they were clinic and not population based. Asperger (1944) noted that only one of his 200 cases developed schizophrenia. The true prevalence of psychiatric illnesses can be calculated only from an epidemiological study, including people with the syndrome not referred to psychiatric services.
Even in the absence of recognizable psychiatric disorder, adolescence may be a difficult time. The development of partial insight and increasing sexual awareness can cause much unhappiness (No. I) and may lead to socially unacceptable behaviour. Peculiarities which may be ignored in a small child become very obvious in a young adult.
The degree of adjustment eventually achieved appears to be related to the level and variety of skills available and also to the temperament of the individual concerned. Good self-care, a special ability that can be used in paid employment, and a placid nature are needed if a person with Asperger syndrome is to become socially independent.
Aetiology and pathology
Asperger (1944) considered his syndrome to be genetically transmitted. He reported that the characteristics tended to occur in the families, especially the fathers of those with the syndrome. Van Krevelen (1971) stated that, in many cases, the antecedents for generations back had been highly intellectual. In the present author's series, 55% had fathers who were in professional or managerial occupations, but the personalities of the parents were not studied systematically. In many cases, the mother alone was seen. The purpose of the interview was to discuss the problems of the child, not to investigate the parents. Including only those concerning whom some tentative conclusions could be drawn (from clinical impressions or evidence from other sources), it appeared that 5 out of 16 fathers and 2 out of 24 mothers had, to a marked degree, behaviour resembling that found in Asperger syndrome. No features of the clinical picture appeared to be associated with higher or lower social class, level of education of the parents, or their personalities.
It is difficult to interpret the findings on social class, since the cases referred to clinics having a special interest in such problems are a selected group, with a strong bias towards higher social class and intellectual occupations in the parents. Schopler et al (1979) and Wing (1980) noted a similar bias in the fathers of classically autistic children referred to clinics, which was not reflected in less selected groups with the same diagnosis. The findings concerning the parents' personalities have to be treated with caution because of the way they were obtained and the lack of any comparison group.
The syndrome can be found in children and adults with history of pre-, pen- or post-natal conditions, such as anoxia at birth, that might have caused cerebral damage. This was true of nearly half of those seen by the present author (Nos. 3 and 4). Mnukhin & Isaev (1975) considered that the behaviour pattern was due to organic deficiency of brain function.
Emotional causes or abnormal child-rearing methods have been suggested, especially where the parents or siblings show similar peculiarities to the patient, but there is no evidence to support such theories.
Detailed epidemiological studies, based on total populations, are needed in order to establish which, if any, of these aetiological factors are relevant.
No specific organic pathology has been identified. No particular abnormalities of face or body have been reported. In childhood the physical appearance is usually, but by no means always, normal. In adolescence and adult life, the inappropriate gait, posture and facial expression produce an impression of oddness.
In general, on psychological assessment, tests requiring good rote memory are performed well, but deficits are shown with those depending on abstract concepts, or sequencing in time. Visuo-spatial abilities vary and the scores on testing may be markedly lower than those for expressive speech (No.4). The results of psychological testing will be described in more detail elsewhere.
Epidemiology
As already mentioned, no detailed, large-scale epidemiological studies have been carried out, so that the exact prevalence of Asperger syndrome is unknown. A major difficulty in designing such a study would be the establishment of criteria for distinguishing the syndrome from other similar conditions, as will be discussed later.
Wing & Gould (1979) carried out a study in which all the mentally and physically handicapped children aged under 15 in one area of London were screened in order to identify cases of early childhood psychosis and severe mental retardation. In this study, two children (0.6 per 10,000 aged under 15) showed most of the characteristics of Asperger syndrome, though they were in the mildly retarded range on intelligence tests, and 4 (1.1 per 10,000) could have been diagnosed as autistic in early life, but came to resemble Asperger syndrome later. There was a total of 35,000 children aged under 15 in the area.
Wing & Gould did not use methods designed to identify mild cases of Asperger syndrome, so that any children who were attending normal school and had not come to the attention of the educational, social or medical services would not have been discovered. The prevalence rate for the typical syndrome given above is almost certainly an underestimate.
The syndrome appears to be considerably more common in boys than in girls. Asperger originally believed it to be confined to males, though he modified this view later (personal communication). Wolff & Barlow (1979) mentioned that the clinical picture could be seen in girls. In their series the male:female ratio was 9:1. In the present author's series there were 15 boys and 4 girls with the syndrome in fairly typical form, and 13 boys and 2 girls who had many of the features. The girls tended to appear superficially more sociable than the boys, but closer observation showed that they had the same problems of two-way social interaction.
Differential diagnosis
As with any condition identifiable only from a pattern of abnormal behaviour, each element of which can occur in varying degrees of severity, it is possible to find people on the borderlines of Asperger syndrome in whom diagnosis is particularly difficult. Whereas the typical case can be recognised with ease by those with experience in the field, in practice it is found that the syndrome shades into eccentric normality, and into certain other clinical pictures. Until more is known of the underlying pathology, it must be accepted that no precise cut-off points can be defined. The diagnosis has to be based on the full developmental history and presenting clinical picture, and not on the presence or absence of any individual item.
Normal variant of personality
All the features that characterise Asperger syndrome can be found in varying degrees in the normal population. People differ in their levels of skill in social interaction and in their ability to read nonverbal social cues. There is an equally wide distribution in motor skills. Many who are capable and independent as adults have special interests that they pursue with marked enthusiasm. Collecting objects such as stamps, old glass bottles, or railway engine numbers are socially accepted hobbies. Asperger (1979) pointed out that the capacity to withdraw into an inner world of one's own special interests is available in a greater or lesser measure to all human beings. He emphasised that this ability has to be present to marked extent in those who are creative artists or scientists. The difference between someone with Asperger syndrome and the normal person who has a complex inner world is that the latter does take part appropriately in two-way social interaction at times, while the former does not. Also, the normal person, however elaborate his inner world, is influenced by his social experiences, whereas the person with Asperger syndrome seems cut off from the effects of outside contacts.
A number of normal adults have outstandingly good rote memories and even retain eidetic imagery into adult life. Pedantic speech and a tendency to take things literally can also be found in normal people.
It is possible that some people could be classified as suffering from Asperger syndrome because they are at the extreme end of the normal continuum on all these features. In others, one particular aspect may be so marked that it affects the whole of their functioning. The man described by Luria (1965), whose visual memories of objects and events were so vivid and so permanent that they interfered with his comprehension of their significance, seemed to have behaved not unlike someone with Asperger syndrome. Unfortunately, Luria did not give enough details to allow a diagnosis to be made.
Even though Asperger syndrome does appear to merge into the normal continuum, there are many cases in whom the problems are so marked that the suggestion of a distinct pathology seems a more plausible explanation than a variant of normality.
Schizoid personality
The lack of empathy, single-mindedness, odd communication, social isolation and over-sensitivity of people with Asperger syndrome are features that are also included in the definitions of schizoid personality (see review by Wolff & Chick, 1980). Kretschmer (1925) outlined some case histories of so-called schizoid adults, one or two of which were strongly reminiscent of this condition, although he did not provide sufficient detail to ensure the diagnosis. For example, one young man had no friends at school, was odd and awkward in social interaction, always had difficulty with speech, never took part in rough games, was oversensitive, and very unhappy when away from home. He thought out fantastic technical inventions and, together with his sister, invented a detailed imaginary world.
There is no question that Asperger syndrome can be regarded as a form of schizoid personality. The question is whether this grouping is of any value. This will be discussed below in the section on classification.
Schizophrenia
Adults with Asperger syndrome may be diagnosed as suffering from schizophrenia. The differential diagnosis of schizophrenia has been discussed elsewhere (J.K.Wing, 1978). The main difficulty arises from the fact that schizophrenia has been defined loosely by some and strictly by other workers.
If a loose definition of schizophrenia is accepted, based only on characteristics such as social withdrawal and speech disorder, then a case could perhaps be made for including Asperger syndrome in this group. As with schizoid personality, the question is whether doing so has any advantages. Poverty of social interaction and abnormalities of speech can have many different causes, so the diagnosis of chronic or simple schizophrenia tends to cover a variety of conditions having little in common with each other.
Careful observation of speech in Asperger syndrome discloses differences from thought blocking and the 'knight's move' in thought described by Bleuler (1911). In Asperger syndrome, speech may be slow, and there may be irrelevant or tangential replies to questions, but these problems are due partly to a tendency to become stuck in well-worn conversational grooves rather than to produce new ideas. Utterances are always logical, even if they are unrelated to the question, or originated from an unusual point of view. Thus one young man, when asked a general knowledge question about organised charities, said 'They do things for unfortunate people. They provide wheelchairs, stilts and round shoes for people with no feet'. There is a marked contrast between the vague woolliness of schizophrenic thought and the concrete, pedantic approach found in Asperger syndrome.
The term schizophrenia can be used more strictly. It can be confined to those who have, currently or in the past, shown the florid first-rank symptoms described by Schneider (1971). In this case, the differentiation of Asperger syndrome rests on accurate definition of the clinical phenomena. Unless they have a superimposed schizophrenic illness, people with Asperger syndrome do not experience thought echo, thought substitution or insertion, thought broadcast, voices commenting on their actions, voices talking to each other, or feelings that external forces are exerting control over their will, emotions or behaviour. The young man, L.P. (Appendix No. 2), when asked if he had such experiences, gave the matter long and careful thought and then said, 'I believe such things to be impossible'.
During clinical examination it is necessary to be aware that comprehension of abstract or unfamiliar concepts is impaired in Asperger syndrome. Those with the more severe form of the handicap may have a habit of answering 'yes' to any question they do not understand, this being the quickest way to cut short the conversation. Some may also pick up and repeat phrases used by other people, including other patients in a hospital ward, making diagnosis even more difficult.
Other psychotic syndromes
The tendency found in people with Asperger syndrome to sensitivity and over-generalisation of the fact that they are criticised and made fun of may, if present in marked form, be mistaken for a paranoid psychosis. Those who are pre-occupied with abstract theories or their own imaginary world may be said to have delusions or hallucinations. One boy, for example, was convinced that Batman would arrive one day and take him away as his assistant. No rational argument could persuade him otherwise. This type of belief could be called a delusion, but is probably better termed an 'over-valued idea'. It does not have any specific diagnostic significance, since such intensely held ideas can be found in different psychiatric states.
Severe social withdrawal, echopraxia and odd postures may be noted. These may become more marked at times, and then they could be regarded as catatonic phenomena. Such catatonic symptoms can be associated with various conditions (including encephalitis) and, on their own, should not be considered as indicative of schizophrenia.
Obsessional neurosis
Repetitive interests and activities are part of Asperger syndrome, but the awareness of their illogicality and the resistance to their performance characteristic of the classic case of obsessional neurosis are not found in the former It would be of interest to investigate the relationship between Asperger syndrome, obsessional personality, obsessional illness, and post-encephalitic obsessional conditions.
Affective conditions
The quietness, social withdrawal, and lack of facial expression in Asperger syndrome might suggest a depressive illness. Shyness and distress when away from familiar surroundings could make an anxiety state a possible diagnosis, or excited talking about a rather fantastic grandiose, imaginary world might bring to mind hypomania. However, the full clinical picture and the early developmental history should clarify the diagnosis.
More difficult problems occur when affective illnesses are superimposed on Asperger syndrome. Then a double diagnosis has to be made on the history and present state.
Early childhood autism
Asperger acknowledged that there were many similarities between his syndrome and Kanner's early infantile autism. Nevertheless, he considered they were different because he regarded autism as a psychotic process, and his own syndrome as a stable personality trait. Since neither psychotic process nor personality trait has been defined empirically, little more can be said about whether they can be distinguished from each other.
Van Krevelen (1971) and Wolff & Barlow (1979) agreed with Asperger that his syndrome should be differentiated from autism. They differ in their accounts of the distinguishing features and the impression gained from their papers is that, although there are some differences, the syndromes are more alike than unalike. The variations could be explained on the basis of the severity of the impairments, though the authors quoted above would not agree with this hypothesis. Thus the autistic child, at least when young, is aloof and indifferent to others, whereas the child with Asperger syndrome is passive or makes inappropriate one-sided approaches. The former is mute or has delayed and abnormal speech, whereas the latter learns to speak with good grammar and vocabulary (though he may, when young, reverse pronouns), but the content of his speech is inappropriate for the social context and he has problems with understanding complex meanings. Non-verbal communication is severely impaired in both conditions. In autism, in the early years, there may be no use of gesture to communicate. In Asperger syndrome there tends to be inappropriate use of gesture to accompany speech. In both conditions, monotonous or peculiar vocal intonation is characteristic. The autistic child develops stereotyped, repetitive routines involving objects or people (for example, arranging toys and household objects in specific abstract patterns, or insisting that everyone in a room should cross the right leg over the left), whereas the person with Asperger syndrome becomes immersed in mathematical abstractions, or amassing facts on his special interests. Abnormal responses to sensory input - including indifference, distress and fascination - are characteristic of early childhood autism and form the basis of the theories of perceptual inconstancy put forward by Ornitz & Ritvo (1968) and of over-selectivity of attention suggested by Lovaas et al (1971). These features are associated with greater severity of handicap, and lower mental age. They are not described as typical of Asperger syndrome, and they are rarely seen in older autistic people with intelligence quotients in the normal range.
The one area in which this type of comparison does not seem to apply is in motor development. Typically, autistic children tend to be good at climbing and balancing when young. Those with Asperger syndrome, on the other hand, are notably il1-co-ordinated in posture, gait and gestures. Even this may not be a particularly useful point of differentiation, since children who have typical autism when young tend to become clumsy in movernent and much less attractive and graceful in appearance by the time of adolescence (see DeMyer, 1976, 1979 for a discussion of motor skills in autism and autistic-like conditions).
Bosch (1962) considered that Asperger syndrome and autism were variants of the same condition. This author pointed out that, although Asperger and Van Krevelen (1971) listed features in the early history which they thought distinguished the two conditions, in practice these did not cluster into two groups often enough to justify the differentiation. The child in Appendix No. 6 illustrates this problem (see also Everard 1980).
Classification
Asperger regarded the syndrome he described as a disorder of personality that could be distinguished from other types of personality abnormalities although he recognised the similarities to early childhood autism. Wolff & Barlow (1979) argued that it should be classified under the heading of schizoid personality. In support of this view, Wolff & Chick (1980) reviewed the literature in which schizoid characteristics are described. As discussed above, the syndrome can be placed in this group, and further work in this field would be of interest, but, at the moment, classification under this heading has no useful practical implications. Although Wolff & Chick have listed five features, operationally defined, that they regard as core characteristics of schizoid personality, this term, as generally used, is so vague and ill-defined a concept that it covers a wide range of clinical pictures in addition to Asperger syndrome. The aim should be not to enlarge, but to separate sub-groups from the broad category and thus to increase diagnostic precision. Furthermore, the word schizoid was originally chosen to underline the relationship of the abnormal personality to schizophrenia. The latter can occur in a person with Asperger syndrome, but, as already discussed, there is not firm evidence of a special link between this syndrome and schizophrenia, strictly defined. To incorporate such an untested assumption into the name of the condition must give rise to confusion.
The reasons for personality variations are so obscure that classifying Asperger syndrome under this heading does not lead to any testable hypotheses concerning cause, clinical phenomena, pathology or management. A more limited, but more productive, view of the problem is to consider it as a consequence of impairment of certain aspects of cognitive and social development.
As mentioned above, Wing & Gould (1979) carried out an epidemiological study of all mentally or physically handicapped children in one area of London, in an attempt to identify all those with autism or autistic-like conditions, whatever their level of intelligence. The results confirmed the following hypothesis. Certain problems affecting early child development tend to cluster together: namely, absence or impairment of two-way social interaction; absence or impairment of comprehension and use of language, non-verbal as well as verbal; and absence or impairment of true, flexible imaginative activities, with the substitution of a narrow range of repetitive, stereotyped pursuits. Each aspect of this triad can occur in varying degrees of severity, and in association with any level of intelligence as measured on standardised tests.
When all children with this cluster of impairments were examined, it was found that a very few resembled the description given by Asperger and some had typical Kanner's autism. A number could, tentatively, be classified as having syndromes described by authors such as De Sanctis (1906, 1908), Earl (1934), Heller (see Hulse, 1954) and Mahler (1952), although the definitions given by these writers were not precise enough for easy identification. The remainder had features of more than one of these so-called syndromes and under the general, but unsatisfactory, heading of early childhood psychosis. The justification for regarding them as related is that all the conditions in which the triad of language and social impairments occurs, whatever the level of severity, are accompanied by similar problems affecting social and intellectual skills. Furthermore, individuals with the triad of symptoms all require the same kind of structured, organised educational approach, although the aims and achievements of education will vary from minimal self-care up to a university degree, depending on the skills available to the person concerned.
This hypothesis does not suggest that there is a common gross aetiology. This is certainly not the case, since many different genetic or pre-, peri- or pos...
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