The advantage of reading over listening text comprehension in Down syndrome: what is the role of verbal memory?

The current study was designed to investigate the role played by verbal memory in the advantage shown by individuals with Down syndrome in reading over listening text comprehension (Roch & Levorato, 2009). Two different aspects of verbal memory were analyzed: processing load and coding modality. Participants were 20 individuals with Down syndrome, aged between 11 and 26 years who were matched for reading comprehension with a group of 20 typically developing children aged between 6;3 and 7;3 years. The two groups were presented with a listening comprehension test and four verbal memory tasks in which the degree of processing load and the coding modality were manipulated. The results of the study confirmed the advantage of reading over listening comprehension for individuals with Down syndrome. Furthermore, it emerged that different aspects of verbal memory were related respectively to reading and to listening comprehension: visual memory with low processing load was related to the former and oral memory with high processing load to the latter. Finally, it was demonstrated that verbal memory contributed to explain the advantage of reading over listening comprehension in Down syndrome. The results are discussed in light of their theoretical relevance and practical implications.