title: Complex syntax in autism spectrum disorders: a study of relative clauses.
abstract: BACKGROUND
  The few studies that have evaluated syntax in autism spectrum disorder (ASD) have yielded conflicting findings: some suggest that once matched on mental age, ASD and typically developing controls do not differ for grammar, while others report that morphosyntactic deficits are independent of cognitive skills in ASD. There is a need for a better understanding of syntax in ASD and its relation to, or dissociation from, nonverbal abilities.
  
  
  OBJECTIVE
  Syntax in ASD was assessed by evaluating subject and object relative clause comprehension in adolescents and adults diagnosed with ASD with a performance IQ within the normal range, and with or without a history of language delay.
  
  
  METHODS
  Twenty-eight participants with ASD (mean age 21.8) and 28 age-matched controls (mean age 22.07) were required to point to a character designated by relative clauses that varied in syntactic complexity.
  
  
  RESULTS
  Scores indicate that participants with ASD regardless of the language development history perform significantly worse than age-matched controls with object relative clauses. In addition, participants with ASD with a history of language delay (diagnosed with high-functioning autism in the DSM-IV-TR) perform worse on subject relatives than ASD participants without language delay (diagnosed with Asperger syndrome in the DSM-IV-TR), suggesting that these two groups do not have equivalent linguistic abilities. Performance IQ has a positive impact on the success of the task for the population with ASD.
  
  
  CONCLUSIONS
  This study reveals subtle grammatical difficulties remaining in adult individuals with ASD within normal IQ range as compared with age-matched peers. Even in the absence of a history of language delay in childhood, the results suggest that a slight deficit may nevertheless be present and go undetected by standardized language assessments. Both groups with and without language delay have a similar global performance on relative clause comprehension; however, the study also indicates that the participants with reported language delay show more difficulty with subject relatives than the participants without language delay, suggesting the presence of differences in linguistic abilities between these subgroups of ASD.
authors.affiliation: Institute of Cognitive Science, CNRS, Lyon, France; Department of Linguistics, University of Geneva, Geneva, Switzerland.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Durrleman
authors.forename: Loyse
authors.initials: L
authors.lastname: Hippolyte
authors.forename: Sandrine
authors.initials: S
authors.lastname: Zufferey
authors.forename: Katia
authors.initials: K
authors.lastname: Iglesias
authors.forename: Nouchine
authors.initials: N
authors.lastname: Hadjikhani
mesh_terms: D000293:Adolescent; D000328:Adult; D020817:Asperger Syndrome / Q000175:diagnosis* / Q000523:psychology; D001308:Auditory Perceptual Disorders / Q000175:diagnosis* / Q000523:psychology; D000067877:Autism Spectrum Disorder / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D007360:Intelligence; D007805:Language Development Disorders / Q000175:diagnosis* / Q000523:psychology; D007807:Language Tests; D008297:Male; D011578:Psycholinguistics; D012016:Reference Values; D012660:Semantics; D013068:Speech Production Measurement; D055815:Young Adult
keywords: Asperger syndrome; French; autism spectrum disorders; language delay; relative clauses; syntax