Verbal short-term memory in Down's syndrome: an articulatory loop deficit?
Down syndrome verbal memory gaps come from overloaded executive skills, not faulty articulation parts.
01Research in Context
What this study did
Hawley et al. (2004) compared teens with Down syndrome to mental-age matched kids.
They gave digit-span tasks and special tests for the articulatory loop parts.
The goal was to see if smaller verbal spans came from broken loop pieces.
What they found
The DS group did recall fewer digits, but the loop parts worked fine.
No sign of slow subvocal rehearsal or a weak phonological store.
The authors blame central executive trouble instead.
How this fits with other research
H-Fournier et al. (2004) ran a close cousin study and got the same negative result.
They also found faster speaking rates in DS, not slower, backing the central-executive idea.
Yang et al. (2014) later showed that better executive functions link to bigger vocabularies in adults with DS, extending the central-executive angle into language gains.
Roch et al. (2012) looked positive on the surface—reading beat listening in DS—but the win came from low visual memory load, again hinting that load on central resources, not articulation speed, limits performance.
Why it matters
Stop drilling faster rehearsal or clearer articulation in isolation.
Target executive supports: cut task steps, give visual cues, teach self-counting or chunking.
These tweaks should lighten central load and let verbal memory grow.
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02At a glance
03Original abstract
BACKGROUND: Verbal short-term memory, as measured by digit or word span, is generally impaired in individuals with Down's syndrome (DS) compared to mental age-matched controls. Moving from the working memory model, the present authors investigated the hypothesis that impairment in some of the articulatory loop sub-components is at the base of the deficient maintenance and recall of phonological representations in individuals with DS. METHODS: Two experiments were carried out in a group of adolescents with DS and in typically developing children matched for mental age. In the first experiment, the authors explored the reliance of these subjects on the subvocal rehearsal mechanism during a word-span task and the effects produced by varying the frequency of occurrence of the words on the extension of the word span. In the second experiment, they investigated the functioning of the phonological store component of the articulatory loop in more detail. RESULTS: A reduced verbal span in DS was confirmed. Neither individuals with DS nor controls engaged in spontaneous subvocal rehearsal. Moreover, the data provide little support for defective functioning of the phonological store in DS. CONCLUSIONS: No evidence was found suggesting that a dysfunction of the articulatory loop and lexical-semantic competence significantly contributed to verbal span reduction in subjects with DS. Alternative explanations of defective verbal short-term memory in DS, such as a central executive system impairment, must be considered.
Journal of intellectual disability research : JIDR, 2004 · doi:10.1111/j.1365-2788.2004.00478.x