Abstract
Background: Recent studies have indicated that many children with autism spectrum disorders present with language difficulties that are similar to those of children with specific language impairments, leading some to argue for similar structural deficits in these two disorders.
Aims: Repetition of sentences involving long-distance dependencies was used to investigate complex syntax in these groups.
Methods & Procedures: Adolescents with specific language impairments (mean age = 15;3, n = 14) and autism spectrum disorders plus language impairment (autism plus language impairment; mean age = 14;8, n = 16) were recruited alongside typically developing adolescents (mean age = 14;4, n = 17). They were required to repeat sentences containing relative clauses that varied in syntactic complexity.
Outcomes & Results: The adolescents with specific language impairments presented with greater syntactic difficulties than the adolescents with autism plus language impairment, as manifested by higher error rates on the more complex object relative clauses, and a greater tendency to make syntactic changes during repetition.
Conclusions & Implications: Adolescents with specific language impairments may have more severe syntactic difficulties than adolescents with autism plus language impairment, possibly due to their short-term memory limitations.
Acknowledgements
The authors wish to thank Autism Speaks/The National Alliance for Autism Research for their generous funding; the parents/guardians and individuals who participated in the study; and Susie Chandler, Abigail Davison-Jenkins, Ann Ozsivadjian, and Vicky Slonims for their help in screening the participants with autism spectrum disorders (ASD). The first author wishes to thank Colin Bannard at the Max Planck Institute, Leipzig, Germany, for explaining the concept of the Levenshtein Distance; and Michael Gilleland of Merriam Park software for publishing a procedure to calculate the Levenshtein Distance on the internet, which was used during data analysis. The authors would also like to thank the two anonymous reviewers for their valuable comments on the manuscript. Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.