Nonverbal Assessment of IQ, Attention, and Memory Abilities in Children with Fragile-X Syndrome Using the Leiter-R

Abstract

This study examined the clinical utility of the recently revised Leiter International Performance Scale (Leiter-R) with a sample of children with fragile-X syndrome. The sample included 25 male children ranging in age from 4.0 to 12.8 years and was 92% European American. All subjects were administered the entire Attention and Memory Battery, and the four subtests from the Visualization and Reasoning Battery that comprise the Brief IQ composite. These tasks were selected to address specific concerns pertaining to memory and attention in individuals with fragile-X. Initial examination of the data revealed that all of the children completed the subtests comprising the Brief IQ and, outside of the Attention Divided subtest, over 80% of the children completed most of the subtests on the Attention and Memory Battery. Findings from the Leiter-R were generally consistent with previously reported assessment results with this population. Overall, the sample fell within the mild to moderate range of mental retardation, with over 80% of the group at or below this range of functioning. As a group, relative difficulty was noted on tasks tapping selective attention and working memory. Ipsatively, a relative strength was apparent across cases on the Associated Pairs subtest. Chronological age had a significant moderate positive correlation with the Leiter-R growth score for the composite scales and a significant strong negative correlation with the age-based standard score for Brief IQ. These findings are discussed with respect to the clinical and research applications of the Leiter-R for children with fragile-X as well as for children with other developmental disabilities.