Verbal short-term memory in developmental dyslexia: The role of the temporoparietal area

Developmental dyslexia (DD) is characterized by difficulties in reading but includes a general verbal short-term memory (vSTM) dysfunction. However, the behavioral and brain basis of vSTM deficits within DD are unknown. 81 children with DD and 17 typically developing (TD) children completed MRI and a verbal repetition task in which length (6 and 9-syllable phrases) and meaningfulness of phrases varied (more or less meaningful phrases). A battery of reading, phonological, and vSTM tests was administered to all children with DD. Children with DD had impaired repetition compared to TD, especially when repeating long and non-meaningful phrases. Lower repetition was associated with greater cortical thickness in the left temporoparietal area in DD. The findings enhance our understanding of one of the neurocognitive mechanisms of DD, suggesting that the repetition deficit may be related to the phonological short-term store and the auditory dorsal stream.