Evidence for a Specific Impairment of Serial Order Short‐term Memory in Dyslexic Children

Abstract

In order to better understand the nature of verbal short-term memory (STM) deficits in dyslexic children, the present study used the distinction between item and serial order retention capacities in STM tasks. According to recent STM models, storage of verbal item information depends very directly upon the richness of underlying phonological and semantic representations. On the other hand, storage of serial order information appears to reflect a language-independent system. Hence, if there is a fundamental STM deficit in dyslexia that is not to be explained only by the poor phonological processing abilities that characterize dyslexia, then difficulties in serial order STM should also be observed in dyslexic children. We administered tasks maximizing either serial order or item retention capacities to dyslexic children and reading age (RA) and chronological age (CA) matched controls. Dyslexic children performed significantly poorer than the CA controls on the item STM measure. Furthermore, the dyslexic group obtained inferior performance than both CA and RA control groups on the serial order STM measure. These findings highlight a severe impairment of STM for serial order information in dyslexia that cannot be reduced to a phonological processing impairment. Implications of serial order retention deficits for reading acquisition and dyslexia are discussed.

Order short-term memory is not impaired in dyslexia and does not affect orthographic learning

“…As the results of this replication study show that dyslexics do not suffer from a specific deficit in the consolidation of serial order information in long-term memory, we may wonder whether the problem with storing serial order information is actually not situated in long-term memory but rather in STM. This idea has already been investigated by Martinez Perez and co-authors (Martinez Perez et al, 2012b, 2013) and will also be the main research question of the current study. We will first discuss recent studies and the underlying theoretical assumptions regarding STM deficits in dyslexia.…”

“…Martinez Perez and co-authors (Martinez Perez et al, 2012b, 2013) investigated whether the verbal STM deficits often reported in dyslexia can be explained exclusively by the poor phonological processing abilities that characterize dyslexia or whether dyslexics in fact suffer from an additional deficit at the level of serial order STM. Previously, verbal STM deficits in dyslexia had been mainly investigated using tasks that confounded item and serial order information recall (Kramer et al, 2000; Tijms, 2004).…”

“…On the other hand, storage of serial order information would occur via a language-independent system and should therefore be less sensitive to verbal long-term memory representations. Martinez Perez et al (2012b) argued that if dyslexics would not only show impairments in item STM but would also show impairments in serial order STM, this deficit could not be explained by exclusively referring to poor phonological processing abilities but would be the result of a specific deficit of serial order STM. To investigate this hypothesis they used the distinction between STM for item information and STM for serial order information.…”

“…To investigate this hypothesis they used the distinction between STM for item information and STM for serial order information. In their first seminal study (Martinez Perez et al, 2012b), they administered two tasks designed to maximize either serial order or item retention abilities in a group of dyslexic children, a chronological age-matched group and a reading-level matched group. To assess item retention capacity a non-word delayed repetition task was constructed.…”

Does learning to read shape verbal working memory?

“…More recently, some researchers have highlighted the contribution to decoding skills of either serial order memory capacity (e.g., Majerus, Poncelet, Greffe, & Van der Linden, 2006;Martinez Perez, Majerus, & Poncelet, 2012a) or the consolidation (or transfer) of serial-order information into a stable LTM trace (Szmalec, Loncke, Page, & Duyck, 2011; but see Staels & Van den Broeck, 2014a). For instance, in a 1-year longitudinal study starting in kindergarten, phonemic awareness (assessed by a phoneme identification task) and serial order STM (measured by a serial order reconstruction task 8 ), but not item STM (measured by monosyllabic nonword repetition under articulatory suppression), predicted independent variance in decoding abilities in first grade, even after controlling for nonverbal reasoning, vocabulary, and initial letter knowledge (Martinez Perez, Majerus, Mahot, & Poncelet, 2012b; see also Nithart et al, 2011).…”