While Kanner was describing early infantile autism in the United States, Asperger reported on a series of patients who demonstrated similar presentations. Similar to those with Kanner's infantile autism, these boys demonstrated poor social understanding and skills, intense special interests, and clumsiness but lacked language delay. Asperger referred to these patients as "little professors" (Asperger 1944/1991). The diagnosis of Asperger's disorder came to increased prominence (especially in the United States) during the 1980s. The clinical picture of individuals with Asperger's disorder is notable for the lack of intellectual disability, but as with autistic disorder, variable presentations are common (Table 21–15). The differentiation of Asperger's disorder from autism (especially in individuals with normal intelligence) can be quite difficult, and controversy exists as to whether Asperger's disorder represents a PDD subtype or the highest-functioning portion of an autistic disorder spectrum (South et al. 2005).