Profiling Fragile X Syndrome in males: strengths and weaknesses in cognitive abilities.

The present study examined the cognitive profile in Fragile X Syndrome (FXS) males, and investigated whether cognitive profiles are similar for FXS males at different levels of intellectual functioning. Cognitive abilities in non-verbal, verbal, memory and executive functioning domains were contrasted to both a non-verbal and verbal mental age reference. Model-based cluster analyses revealed three distinct subgroups which differed in level of functioning, but showed similar cognitive profiles. Results showed that cognitive performance is particularly weak on measures of reasoning- and performal abilities confined to abstract item content, but relatively strong on measures of visuo-perceptual recognition and vocabulary. Further, a significant weakness was found for verbal short-term memory. Finally, these results indicated that the choice of an appropriate reference is critically important in examining cognitive profiles. The pattern of findings that emerged from the current cognitive profiling of FXS males was interpreted to suggest a fundamental deficit in executive control.