title: Discourse skills of boys with fragile X syndrome in comparison to boys with Down syndrome.
abstract: OBJECTIVE
  This study compared the conversational discourse skills of boys who have fragile X syndrome with and without autism spectrum disorder (ASD) with those of boys with Down syndrome and boys who are typically developing.
  
  
  METHODS
  Participants were boys who have fragile X syndrome with (n = 26) and without (n = 28) ASD, boys with Down syndrome (n = 29), and boys who are typically developing (n = 22). Turns during an examiner-child interaction consisting of structured and semistructured activities were coded for the boys' ability to maintain a topic of conversation and the frequency of perseveration.
  
  
  RESULTS
  The results revealed that boys who had both fragile X and ASD produced significantly more noncontingent discourse than did boys who had only fragile X, boys with Down syndrome, or typically developing boys. This finding was observed regardless of whether the topic was maintained or changed and whether the turn type was a response or initiation. Regardless of autism status, boys with fragile X used more perseveration than did boys in the other groups.
  
  
  CONCLUSIONS
  These findings suggest that some aspects of the conversational discourse difficulties attributed to fragile X syndrome may be a function of the high rate of comorbidity between fragile X and autism, whereas some difficulties may be characteristic of fragile X syndrome.
authors.affiliation: Frank Porter Graham Child Development Institute, University of North Carolina at Chapel Hill, 105 Smith Level Road, CB# 8180, Chapel Hill, NC 27599-8180. joanne_roberts@unc.edu
authors.forename: Joanne
authors.initials: J
authors.lastname: Roberts
authors.forename: Gary E
authors.initials: GE
authors.lastname: Martin
authors.forename: Lauren
authors.initials: L
authors.lastname: Moskowitz
authors.forename: Adrianne A
authors.initials: AA
authors.lastname: Harris
authors.forename: Jamila
authors.initials: J
authors.lastname: Foreman
authors.forename: Lauren
authors.initials: L
authors.lastname: Nelson
mesh_terms: D000293:Adolescent; D001321:Autistic Disorder / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology; D003142:Communication; D004314:Down Syndrome / Q000453:epidemiology*; D005600:Fragile X Syndrome / Q000453:epidemiology*; D006801:Humans; D008297:Male; D033262:Narration; D009633:Nonverbal Communication; D012720:Severity of Illness Index; D013064:Speech Disorders / Q000175:diagnosis* / Q000453:epidemiology*