Discourse processing in women with fragile X syndrome: Evidence for a deficit establishing coherence

The language phenotype in individuals with fragile X syndrome (FXS) and its relation to the molecular genetics of the disorder was investigated. Previ ous research has focused on describing deviance in conversational speech, a nd has not yet examined component discourse skills. The ability of women wi th FXS to use coherence to select endings to humorous and straightforward p assages was evaluated, and the relation of this with neuropsychological mea sures of working memory, executive functions, and molecular measures of the syndrome were also evaluated. Three groups of nonretarded women were exami ned: (a) 14 women with FXS who carry the full mutation; (b) 25 women who ca rry the premutation; and (c) 16 women without the fragile X mutation. The r esults indicated that subjects with the full mutation showed a dramatic def icit in selecting appropriate endings to jokes relative to stories, even th ough the jokes were identical to the stories except for their endings. The coherence deficit found in the jokes task for women with the full mutation was found to correlate strongly with the X activation ratio, and to a neuro psychological measure of working memory. The full mutation subjects' cohere nce deficit is discussed in terms of the additional demand to hold informat ion in memory and shift set.