Do Autism and Specific Language
Impairment Represent Overlap-ping
Boston University School of Medicine
Autism is diagnosed on the basis of impairments in three behavioral domains: communication, social interaction, and repetitive and stereotyped patterns of behavior, interests, and activities (American Psychological Association, 1994). Within the domain of communication, deficits in both verbal and nonverbal aspects of communication are considered key symptoms, and these are frequently the first signs of disorder noted by parents or clinicians (Kurita, 1985; Lord & Paul, 1997). In recent years, much of the focus of research into communication deficits has been on those aspects that are both specific and universal across the spectrum of people with autistic disorder (Tager-Flusberg, 1996). There is a general consensus that pragmatic deficits, especially in conversational discourse and understanding language as a system for communicating intended meaning, are the key universal impairments that define autism (Lord & Paul, 1997; Tager-Flusberg, 1999). At the same time, the majority of individuals with autism also suffer language deficits that go beyond impairments in pragmatics, although these deficits have been relatively understudied by autism researchers (Kjelgaard & Tager-Flusberg, 2001). In this chapter, I explore the hypothesis that among children with autism there is a subgroup that has language impairments that are parallel to those that characterize children with specific language impairment (SLI). I review evidence from our recent behavioral and brain imaging studies, which suggest that this subgroup within the autism spectrum has SLI. In the final section, I consider the implications of this research for genetic studies of both autism and SLI.