Asperger’s Disorder is a milder variant of Autistic Disorder.   Both Asperger’s Disorder and Autistic Disorder are in fact subgroups of a larger diagnostic category.  This larger category is called either Autistic Spectrum Disorders, mostly in European countries, or Pervasive Developmental Disorders (“PDD”), in the United States.  In Asperger’s Disorder, affected individuals are characterized by social isolation and eccentric behavior in childhood. There are impairments in two-sided social interaction and non-verbal communication. Though grammatical, their speech may sound peculiar due to abnormalities of inflection and a repetitive pattern. Clumsiness may be prominent both in their articulation and gross motor behavior. They usually have a circumscribed area of interest which usually leaves no space for more age appropriate, common interests. Some examples are cars, trains, French Literature, door knobs, hinges, cappucino, meteorology, astronomy or history.  The name “Asperger” comes from Hans Asperger, an Austrian physician who first described the syndrome in 1944.

In a total population study of children between ages 7-16 in Goteborg, Sweden, minimum prevalence of Asperger’s Disorder was 36/10,000 (55/10,000 of all boys, and 15/10,000 of all girls), and the male/female ratio was 4:1.
The prevalence of autism has traditionally been estimated around 4-5/10,000.  A recent study from United Kingdom found the prevalence of autism at 17/10,000, and the prevalence of all Autistic Spectrum Disorders (including autism) at 63/10,000.
Despite the now widely accepted fact that biological factors are of crucial importance in the etiology of autism, so far the brain imaging studies have shown no consistent pattern, no consistent evidence of any type of lesion, and no single location of any lesion in subjects with autistic symptoms. This inconsistency in the results of various brain imaging studies has been attributed to the fact that people with autism represent a highly heterogeneous group in terms of underlying pathology. Therefore there is an ongoing effort to specify more homogenous subgroups among autistic individuals to enhance the accuracy of etiologic inquiry. This approach has been supported with the inclusion of the diagnosis ‘Asperger’s Disorder’ in the Fourth Edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) of the American Psychiatric Association.
Associated medical conditions such as fragile-X syndrome, tuberous sclerosis, neurofibromatosis, and hypothyroidism are less common in Asperger’s Disorder than in classical autism. Therefore it may be expected that there are fewer major structural brain abnormalities associated with Asperger’s Disorder than with autism. To our knowledge, a very small number of structural brain abnormalities have been so far associated with Asperger’s Disorder, which include left frontal macrogyria, bilateral opercular polymicrogyria, and left temporal lobe damage. On the other hand brain imaging techniques like positron emission tomography (PET), and single photon emission tomography (SPECT) which provide information about the functional status of brain may be more helpful in determining the brain dysfunction in individuals with Asperger’s Disorder. Detailed neuropsychological testing may support these findings providing information about the performances of individual right or left hemispheric brain regions. The first SPECT study in a patient with Asperger’s Disorder was published by the host of this page and his colleagues, and found left parietooccipital hypoperfusion. Continuation of research in Asperger’s Disorder with various brain imaging techniques in coordination with neuropsychological evaluation in larger samples is clearly needed in this area.
1.Severe impairment in reciprocal social interaction
(at least two of the following)
(a) inability to interact with peers
(b) lack of desire to interact with peers
(c) lack of appreciation of social cues
(d) socially and emotionally inappropriate behavior
2.All-absorbing narrow interest
(at least one of the following)
(a) exclusion of other activities
(b) repetitive adherence
(c) more rote than meaning
3.Imposition of routines and interests
(at least one of the following)
(a) on self, in aspects of life
(b) on others
4.Speech and language problems
(at least three of the following)
(a) delayed development
(b) superficially perfect expressive language
(c) formal, pedantic language
(d) odd prosody, peculiar voice characteristics
(e) impairment of comprehension including misinterpretations of literal/implied meanings
5.Non-verbal communication problems
(at least one of the following)
(a) limited use of gestures
(b) clumsy/gauche body language
(c) limited facial expression
(d) inappropriate expression
(e) peculiar, stiff gaze
6.Motor clumsiness: poor performance on neurodevelopmental examination
(All six criteria must be met for confirmation of diagnosis.)