Research highlights

● This study tested the (co)existence of cognitive deficits in dyslexia in phonological
awareness, rapid naming, visual and selective attention, auditory skills, and implicit
● The most frequent deficits in Polish children with dyslexia included a phonological
(51%) and a rapid naming deficit (26%), which coexisted in 14% of children.
● Despite the severe reading impairment, 26% of children with dyslexia presented no
deficits in measured cognitive abilities.
● RAN explains reading skills variability across the whole spectrum of reading ability;
phonological skills explain variability best among average and good readers but not
poor readers


This study focused on the role of numerous cognitive skills such as phonological awareness (PA), rapid automatized naming (RAN), visual and selective attention, auditory skills, and implicit learning in developmental dyslexia. We examined the (co)existence of cognitive deficits in dyslexia and assessed cognitive skills’ predictive value for reading.

First, we compared school-aged children with severe reading impairment (n = 51) to typical readers (n = 71) to explore the individual patterns of deficits in dyslexia. Children with dyslexia, as a group, presented low PA and RAN scores, as well as limited implicit learning skills. However, we found no differences in the other domains. We found a phonological deficit in 51%, and a RAN deficit in 26% of children with dyslexia. These deficits coexisted in 14% of children. Deficits in other cognitive domains were uncommon and most often coexisted with phonological or RAN deficits. Despite having a severe reading impairment, 26% of children with dyslexia did not present any of the tested deficits.

Second, in a group of children presenting a wide range of reading abilities (N = 211), we analyzed the relationship between cognitive skills and reading level. PA and RAN were independently related to reading abilities. Other skills did not explain any additional variance. The impact of PA and RAN on reading skills differed. While RAN was a consistent predictor of reading, PA predicted reading abilities particularly well in average and good readers with a smaller impact in poorer readers.

Tagged as: implicit learning, orthographic transparency, phonemic awareness, phonological processing, and Rapid automatic naming


Dębska, A., & Łuniewska, M. (2021, May 26). The cognitive basis of dyslexia in school-aged children: a multiple case study in a transparent orthography.

Excerpts from Full Text / Notes:
  • Our results emphasized the independent role of RAN and phonological skills in predicting the
    reading level. This is in line with the double-deficit theory of dyslexia (Wolf & Bowers,
    1999), where RAN and phonological skills are treated as two separate sources of reading
  • In our study, 14% of children with dyslexia showed an implicit learning deficit, and this skill
    differentiated between typical and poor readers. This deficit was not accompanied by any
    other deficit in the case of five out of seven children. . . . In our sample, only one child had coexisting phonological and implicit
    learning deficits. The clear distinction between phonological and implicit learning deficits
    may suggest that implicit learning is a skill that may explain a certain number of dyslexia
    cases independently from RAN and phonology, probably due to the problems with implicit
  • Around 24% of children with dyslexia in our sample showed no apparent cognitive deficit in
    phonology, RAN nor implicit learning.
  • We noted that weak phonological and RAN deficits did not lead to
    dyslexia when not accompanied by each other. Among children who scored below -1SD in
    phonological awareness alone there were 11 typical readers (39%) and 17 children with
    dyslexia (61%), and among children with a weak RAN deficit, there was an equal number of
    typical (n = 10) and impaired readers. However, among children who scored below -1SD in
    phonological and RAN skills at the same time, there were 95% of children with dyslexia (n =
    18) and just one typical reader.
  • Rapid naming appears to be the most stable predictor of reading, regardless of the reading level whereas phonology explains variability in average and good but not poor readers.

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