Phonological skills, visual attention span, and visual stress in developmental dyslexia.

Abstract

In this study, we concurrently investigated 3 possible causes of dyslexia-a phonological deficit, visual stress, and a reduced visual attention span-in a large population of 164 dyslexic and 118 control French children, aged between 8 and 13 years old. We found that most dyslexic children showed a phonological deficit, either in terms of response accuracy (92.1% of the sample), speed (84.8%), or both (79.3%). Deficits in visual attention span, as measured by partial report ability, affected 28.1% of dyslexic participants, all of which also showed a phonological deficit. Visual stress, as measured by subjective reports of visual discomfort, affected 5.5% of dyslexic participants, not more than controls (8.5%). Although phonological variables explained a large amount of variance in literacy skills, visual variables did not explain any additional variance. Finally, children with comorbid phonological and visual deficits did not show more severe reading disability than children with a pure phonological deficit. These results (a) confirm the importance of phonological deficits in dyslexia; (b) suggest that visual attention span may play a role, but a minor one, at least in this population; (c) do not support any involvement of visual stress in dyslexia. Among the factors that may explain some differences with previously published studies, the present sample is characterized by very stringent inclusion criteria, in terms of the severity of reading disability and in terms of exclusion of comorbidities. This may exacerbate the role of phonological deficits to the detriment of other factors playing a role in reading acquisition. (PsycINFO Database Record

Literacy and Phonological Skills in Oral Deaf Children and Hearing Children With a History of Dyslexia

“…Samar and colleagues (Samar & Parasnis, ; Samar et al., ) suggested that all struggling deaf readers could be thought of as dyslexic on the basis of these visual deficits; thus, dyslexia may be the largest secondary disability in the deaf population. However, the role of these and other visual deficits (e.g., visual attention span, visual tracking) in dyslexia among the hearing population is controversial; although they frequently co‐occur, whether they are part of the underlying cause of dyslexia remains unclear (Hulme & Snowling, ; Saksida et al., ; Vellutino et al., ).…”

“…D yslexia and accompanying deficits have been widely researched (Bishop & Snowling, 2004;Lyon, Shaywitz, & Shaywitz, 2003;Peterson & Pennington, 2015;Ramus, 2003;Saksida et al, 2016;Snowling, 2000Snowling, , 2008Vellutino, Fletcher, Snowling, & Scanlon, 2004). With increasing awareness of dyslexia, a diagnosis of dyslexia in the United Kingdom can lead to recognition of children's needs and the provision of specialist support and intervention (Duff & Clarke, 2011).…”

Cross-linguistic transfer in bilinguals reading in two alphabetic orthographies: The grain size accommodation hypothesis

“…However, the prevalence of either type of deficit may differ within a particular dyslexic population. For example, Saksida et al (2016) showed that pure phonological deficits associated with dyslexia were actually much more frequent than pure visual attention span disorders in a French child population. However, Bosse et al (2007) found relatively equal proportions of the two dyslexic types in French and British groups of children.…”

Distinguishing cause from effect – many deficits associated with developmental dyslexia may be a consequence of reduced and suboptimal reading experience

“…To mention just a few, it has been argued that it is "widely agreed that developmental dyslexia is caused by a 'phonological core deficit'" (e.g. Goswami, 2003; and many others, see also Blomert, 2011;Olulade, Napoliello, & Eden, 2013;Saksida et al, 2016;Vellutino, Fletcher, Snowling, & Scanlon, 2004;Wimmer & Schurz, 2010, for recent discussions); that dyslexia is "a deficit in visuospatial attention, not in phonological processing" (Vidyasagar & Pammer, 2010); that "it is illogical to conclude that absence of evidence for some aspects of a magnocellular deficit in some dyslexics is evidence of its absence in all" (Stein, Talcott, & Walsh, 2000); that phonological and magnocellular deficit accounts both fail "to account for the full range of deficits established for dyslexic children … the full range of deficits might be accounted for in terms of a cerebellar deficit" (Nicolson, Fawcett, & Dean, 2001); and that "the cerebellum might stand unfairly accused, an innocent bystander in the processes responsible for disordered motor control in developmental dyslexia … the 'cerebellar' signs and symptoms associated with developmental dyslexia reflect a remote effect of neocortical perisylvian damage on cerebellar function" (Zeffiro & Eden, 2001). It has even been suggested that developmental dyslexia and specific language impairment are points on a continuum of learning disorders rather than distinct disabilities (Kamhi & Catts, 1986;cf.…”