What is not working in working memory of children with literacy disorders? Evidence from a three-year-longitudinal study

The goals of this study were to explore the deficits in working memory associated with literacy disorders (i.e. developmental disorders of reading and/or spelling) and the developmental trajectories of these working memory deficits. The performance of 28 children with literacy disorders was compared to a non-disabled control group with the same group size at five bi-annual times of measurement in a three-year-longitudinal study beginning at the end of primary school (9.5 years of age). Storage capacity and central-executive working memory were assessed in phonological and visual-spatial modalities, the latter under static and dynamic conditions. Overall, children with literacy disorders were outperformed by their typical developing peers in all phonological and in dynamic visual-spatial storage and central-executive tasks except for the static visual-spatial storage task. Results at single times of measurement revealed that the most consistent deficit was found in the storage capacity of the phonological loop. An additional central-executive impairment is supported by low backward spans. The causes for output deficits in dynamic visual-spatial tasks and good performance under static visual-spatial condition are discussed.(DIPF/Orig.