The relevance of a nonword repetition task to assess phonological short-term memory in individuals with Down syndrome

Phonological short-term memory capacity is generally measured with a word span task or a digit span task. Another way to measure it is to use a nonword repetition task. Gathercole and Adams (1993) claimed that this procedure can be used with children as young as two-years old. It seems that in normally developing children the quality of nonword repetition is influenced both by the length of nonwords and by the degree of wordlikeness. Can the phonological short-term memory of individuals with Down syndrome be assessed with a nonword repetition task? In order to answer this question, we decided to replicate Gathercole and collaborators' experiments (1991,1993) but with individuals with Down syndrome. The quality of nonword repetition in individuals with Down syndrome is, as in normally developing children, influenced both by the length of nonwords and by their degree of wordlikeness. Furthermore, our results seem to confirm the hypothesis which states that nonwords are temporarily stored in the phonological short-term memory system. As this system has a limited capacity, both normally developing children and people with Down syndrome recall more short nonwords than long nonwords. In conclusion, nonword repetition is a reliable task with which to assess phonological short-term memory in individuals with Down syndrome as well as in normally developing children.