Abstracts

RATIONALE: Memory tests play an important role in the neuropsychological evaluation of children with epilepsy. However, our understanding of how memory test performance can be affected by deficits of other abilities such as attention is limited. We studied several measures of attention and other neuropsychological skills in relation to memory task performance
Objective - To understand how measures of attention and other skills are related to memory test performance in childhood epilepsy.
METHODS: 35 children from a tertiary pediatric epilepsy center with a mean age of 12.5 [plusminus] 2.1 yrs and a mean seizure onset of 6.3 [plusminus] 3.8 yrs were studied. Neuropsychological testing included the WISC-III, which yielded a mean Full Scale IQ (FSIQ) of 84.6 [plusminus] 16.8, as well as the indices of Verbal Comprehension (VC) and Perceptual Organization (PO) from the WISC-III. Memory indices were generated from the Children[ssquote]s Memory Scale (CMS) and the California Verbal Learning Test [ndash] Children[ssquote]s Revision. Attention measures included the Freedom from Distractibility (FD) and Processing Speed (PS) indices of the WISC-III, a focal attention index from the Cognitive Assessment System (CASFA), and a sustained attention index, the reaction time standard error of the Conners Continuous Performance Test (CPTSE).
RESULTS: Pearson correlations indicated that general verbal and visual memory indices were both associated with FSIQ, VC, and PO. General verbal memory was more strongly associated with VC than with other abilities. All indices of attention except CPTSE were moderately but nonspecifically correlated with general verbal and visual memory. Individual CMS memory subtest correlations revealed a stronger relationship between Story Memory scores and VC than between Story Memory and other indices of ability and attention. In contrast, Word Pairs correlated in a nonspecific manner with all indices of ability and attention except CPTSE. The Facial and Dot Memory tasks yielded generally weaker and nonspecific correlations with measures of ability and attention. CPTSE failed to correlate significantly with any of the memory indices. In regression analyses, only VC contributed uniquely to general verbal memory and Story Memory performance, and only PS to general visual memory.
CONCLUSIONS: Our results suggest that deficits of abilities such as attention and verbal working memory should be regarded with caution as factors that can account for poor memory task performance. Though they correlated with memory indices, their associations tended to be modest and nonspecific. These findings enhance our understanding of factors related to clinical memory test performance and will enable us to better interpret the neuropsychological test results of children with epilepsy. For example, the strong association between narrative memory performance and general verbal ability suggests that narrative memory tasks may be more useful than rote verbal learning procedures in localizing the neural substrate of verbal memory compromise in children with epilepsy. Improved neuropsychological assessment techniques should also allow us to better identify patterns of performance that are indicative of specific epilepsy syndromes.
[Supported by: Internal funding]