Relationship between auditivo-vocal short-term memory and lexical knowledge in Down'syndrome

Some neuropsychological studies of brain damaged patients presenting memory deficits suggest that working memory directly contribute to the long-term learning of non-familiar phonological structures. It seems that a phonological store impairment leads to problems in learning new words (Baddeley, Papagno & Vallar, 1988). Gathercole and Baddeley (1993) studies of normal young children lead to the same conclusion. Phonological short-term memory abilities of 4-5 years-old children directly influence lexical acquisition. Children who exhibit the higher phonological memory skills produce higly discriminable and stable phonological memory traces. For these children, there is a greater probability that memory traces become durable and semanticaly linked to the referent. One can then conclude that the phonological short-term memory abilities directly influence the way young children acquired new vocabulary items. A study of memory abilities and lexical knowledge of Down's syndrome subjects (mental age:3;5 to 5;4 years old, chronological age: 8;10 to 25;11 years old) lead us to the following conclusion: in Down's syndrome subjects, as well as in normal subjects, one cannot reject the hypothesis that lexical knowledge are linked to the subjects phonological short-term memory abilities and more specially to non-word repetition.