Abstracts

Purpose: This study compared the conversational discourse skills of boys who have fragile X syndrome with and without autism spectrum disorder to boys with Down syndrome and boys who are typically developing.
Method: Participants were boys who have fragile X syndrome with (n=26) and without (n=28) autism spectrum disorder, boys with Down syndrome (n=29), and boys who are typically developing (n=22). Turns during an examiner-child interaction consisting of structured and semi-structured 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 autism spectrum disorder produced significantly more noncontingent discourse than 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 the other groups.
Conclusion: 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, while some difficulties may be characteristic of fragile X syndrome.