(excerpt from Romanczyk, R.G., Lockshin, S. & Navalta, C. (1994) Differential Diagnosis of Autism.)
Wing (1981,1989) describes characteristics of Asperger's syndrome, such as "... odd, naive, egocentric style of social interaction; long winded, pedantic, repetitive speech; a limited range of circumscribed interests pursued to the exclusion of other activities; poor coordination of movements; and a conspicuous lack of common sense." (p.6). Asperger's syndrome has received increasing attention in recent years and is a controversial topic. Green, (1990) states that "On most tests of social functioning and neurobiological investigations, including physical disorders chromosome analysis, and brain imaging, Asperger syndrome and infantile autism differ in degree rather than kind, and a number of family pedigrees have been reported in which both Asperger syndrome and infantile autism have been clearly present. All this evidence, along with the clinical similarities, make a strong case for Asperger syndrome being a mild variant of infantile autism." (pp. 744-745). However, there are developmental differences, particularly the absence of early language disorder in Asperger syndrome. There are also differences in current functioning (even when groups are matched for intelligence), including a greater incidence of psychiatric disorder, better educational outcome, a tendency to greater sociability and the presence of clumsiness. Comparing Asperger's syndrome as described by Asperger, and as modified by Wing (1981) and the syndrome of autism as currently defined, it becomes increasingly difficult to reconcile the claim that the syndrome of autism as defined in this way is significantly different from other syndromes unless Asperger's syndrome is admitted to the same diagnostic category. Bowman (1988) describes a family of 4 boys and their father that provides some evidence to support the connection between the two conditions. The youngest boy exhibited the features of Asperger's syndrome, two brothers satisfied the diagnostic criteria for autism, and the fourth boy did not have any clinical symptomatology. All four were of normal intelligence (WISC-R or WAIS). "This evidence supports Wing's (1981) hypothesis that the variation in the two conditions could be explained on the basis of severity." (p. 381). "The evidence in this family suggests that Asperger's syndrome, with its apparently normal verbal intelligence, may be autism in its most pure form." (p. 381) All four boys showed the cognitive and psycholinguistic profile associated with autism. In contrast, Pomeroy, Friedman, and Stephen (1990) state that "With regard to subgroups in PDD, it seems premature to conclude that there are no significant differences between children diagnosed as having high-functioning autism and those considered to have Asperger Syndrome, since "... we are unable to assess whether either group is truly homogeneous and the boundaries of selection are dictated by clinical referral (and, presumably, by the researcher's preconception of the disorder being studied). Potential subgroups could be missed ..." (p. 832). Szatmari, Bartolucci, and Bremner, (1989) examined the diagnostic validity of Asperger's Syndrome (AS) by determining to what extent AS children differ in early history and outcome from two comparison groups, one of non-retarded children with autism, the other a group of children referred to a psychiatric clinic with nonspecific problems in getting along with other children as part of their presenting complaint. The study compared the three groups on their early history and present status. The inclusion criteria for AS was adapted from Wing (1981). Thirty-eight children were referred for the AS group. Ten of these children were eliminated upon assessment. The final AS sample of 28 children comprised 5 females and 23 males. The average age was 14 years. The high functioning autism (HFA) sample consisted of 25 individuals. The average age was 23 years. There were six females and 19 males. Mean IQ of HFA group was 85. The outpatient control (OPC) group consisted of 42 children, 34 males and 8 females. The average age was 14 years. To be included in the study, these children had to have a problem in getting along with other children of the same age, for whatever reason. They also had to match the AS group in age and sex an could not have a history of brain damage. Early history data were available for 27 of 28 AS children and for all but one of the 25 autistic children. These data were gathered from parent interviews, child interviews, and school history forms. Early history information from the parent interview included the following: social responsiveness, deviant language, bizarre behavior, impairments in non-verbal communication, clumsiness, and age at onset. An assessment of current psychiatric symptoms was made from the parent and child versions of the Diagnostic Interview for Children and Adolescents (DICA) (Herjanic & Reich, 1982). Analyses compared the three groups on measures reflecting early history and outcome. The three groups were significantly different on all measures of social responsiveness. The HFA and AS groups differed in their early history of bizarre preoccupations, motor stereotypies, and symptoms of insistence. There was no difference in the ability of the two PDD groups to use or understand non-verbal means of communication. There was no difference among the three groups in performing fine motor activities. Differences in age at onset was not significant. On the DICA, the autism group had fewer schizotypal symptoms than either the AS or OPC groups. All three groups differed with respect to history of special education, with the HFA group having spent more time in special education than the AS group. A cluster analysis of early history variables revealed that the autism group had high scores on all variables and the AS group had low scores on all variables. The main finding of this report is that no substantive, qualitative differences were found between the AS and HFA groups. The authors suggest, based on their results, that "... it may be best to think of AS as a mild form of HFA." (p. 7l7).