Working memory development in individuals with Down syndrome

In past years many studies were carried out on working memory characteristics in Down syndrome. Many of them found an impairment in verbal working memory, while visuo-spatial working memory was relatively preserved. Furthermore it seems that the working memory component more impaired in individuals with Down syndrome is the central executive. Lanfranchi et al. (2004) found that the differences between Down syndrome children and same mental age typically developing children increase the more central executive work is required by the task, both in verbal than in visuo-spatial working memory tasks. The largest differences between Down syndrome individuals and controls were found in tasks requiring high controlled processes on items to be remembered. However we have only little knowledge about working memory development in Down syndrome. On the basis of these considerations the present study is aimed at analysing working memory development in Down syndrome. Fifty-eight individuals with Down syndrome, divided into three groups on the basis of their chronological age (6-10, 11-15, 16-20 years old) took part in this study. They were administered three verbal and three visuo-spatial working memory tasks, requiring different degrees of control: low, medium and high. We also assessed some other cognitive abilities that in typical development are considered to be strictly linked to working memory, such as verbal abilities, performance abilities and logical thinking. Our data showed a significant effect of age on performances in both verbal and visuo-spatial working memory tasks. We also analysed the correlation values between the threeworking memory components in the three age groups and we found some differences that could be explained in terms of different involvement of the intellectual structures. Finally, we found interesting differences between the three groups in correlation values between working memory and verbal abilities, performance abilities and logical thinking. Results are discussed both in relation to the Down syndrome cognitive profile and to the trends in typical development.