Abstract
OBJECTIVES: The overall goal of this study was to compare verbal and visuospatial working memory in children with normal hearing (NH) and with cochlear implants (CI). The main questions addressed by this study were (1) Does auditory deprivation result in global or domain-specific deficits in working memory in children with CIs compared with their NH age mates? (2) Does the potential for verbal recoding affect performance on measures of reasoning ability in children with CIs relative to their NH age mates? and (3) Is performance on verbal and visuospatial working memory tasks related to spoken receptive language level achieved by children with CIs? DESIGN: A total of 54 children ranging in age from 5 to 9 years participated; 25 children with CIs and 29 children with NH. Participants were tested on both simple and complex measures of verbal and visuospatial working memory. Vocabulary was assessed with the Peabody Picture Vocabulary Test (PPVT) and reasoning abilities with two subtests of the WISC-IV (Wechsler Intelligence Scale for Children, 4th edition): Picture Concepts (verbally mediated) and Matrix Reasoning (visuospatial task). Groups were compared on all measures using analysis of variance after controlling for age and maternal education. RESULTS: Children with CIs scored significantly lower than children with NH on measures of working memory, after accounting for age and maternal education. Differences between the groups were more apparent for verbal working memory compared with visuospatial working memory. For reasoning and vocabulary, the CI group scored significantly lower than the NH group for PPVT and WISC Picture Concepts but similar to NH age mates on WISC Matrix Reasoning. CONCLUSIONS: Results from this study suggest that children with CIs have deficits in working memory related to storing and processing verbal information in working memory. These deficits extend to receptive vocabulary and verbal reasoning and remain even after controlling for the higher maternal education level of the NH group. Their ability to store and process visuospatial information in working memory and complete reasoning tasks that minimize verbal labeling of stimuli more closely approaches performance of NH age mates.