Revisiting the phonological deficit in dyslexia: Are implicit nonorthographic representations impaired?

Abstract

This study investigates whether developmental dyslexia involves an impairment in implicit phonological representations, as distinct from orthographic representations and metaphonological skills. A group of adults with dyslexia was matched with a group with no history of speech/language/literacy impairment. Tasks Developmental dyslexia is widely believed to be caused either mainly (Snowling, 2000;Ramus, 2003) or in part (Stein & Walsh, 1997;Wolf et al., 2002) by a phonological deficit. In contexts where individuals with dyslexia are required to demonstrate a mastery of phonological units such as phonemes and syllables, their performance is consistently found to be weaker than that of controls matched for chronological age and/or reading age. This includes performance on phoneme deletion (Fawcett & Nicolson, 1995;Wilson & Lesaux, 2001), phoneme counting (Bruck, 1992), and syllable counting or deletion tasks (Pratt & Brady, 1988). Other tasks with a phonological component, such as rapid naming and nonword repetition, also elicit weaker performance from dyslexic than non-dyslexic individuals (Denckla & Rudel, 1976;Brady, 1991).A broad consensus has arisen in the field that this phonological deficit can be traced back to an impairment of phonological representations or phonological coding, defined as "the ability to use speech codes to represent information in the forms of words and word parts" (Vellutino, Fletcher, Snowling, & Scanlon, 2004: 12).Phonological representations have been implicated as causally linked to all the various manifestations of the phonological deficit, from paired associate learning and nonword repetition, to phonological awareness and reading (Brady, 1991;Ramus, 2003;Ramus, Pidgeon, & Frith, 2003;Snowling, 2000;Stanovich, 1988;Thomson, Richardson, & Goswami, 2005).However, two issues relating to phonological representations in dyslexia require further attention. One is the relationship between phonemes (as phonological Phonological deficit 5 segments) and the segments of conventional orthography (letters or graphemes). The other is the relationship between phonological awareness and phonological representations. Let us now consider each of these issues in turn. Phonological and orthographic segmentsOne controversial issue in dyslexia research is the nature of the relationship between phonological knowledge and familiarity with a writing system. Although spoken language and written language differ from each other in many significant ways, the two modalities nevertheless have a great deal in common. Current influential accounts of dyslexia seek to relate the deficit in written language to a deficit in aspects of spoken language (Snowling, 2000;Ramus, 2003), but the challenge which confronts this approach is the issue of how to handle what Harris (2000) calls the "symbiotic relationship" between these two modalities.Learning to read and write in any orthographic system means that learners have to reshape their analyses of the sounds of words so as to match the analysis conveyed or ...

Investigating the role of visual and auditory search in reading and developmental dyslexia

“…Why this particular “signal-to-noise ratio” may be relevant for literacy development is an open question, but some studies looking at speech-in-noise deficits in developmental dyslexia could shed light on it (Ziegler et al, 2009; Dole et al, 2012). In particular, we found that auditory search performance was unrelated to phonological awareness (see also Lallier et al, 2012) which is supported by studies that show a relative independence between speech-in-noise deficits and other phonological deficits (Robertson et al, 2009; Ziegler et al, 2009; Messaoud-Galusi et al, 2011; Berent et al, 2012; Dickie et al, 2012). Speech-in-noise skills of dyslexic children also seem to dissociate from slow rate dynamic auditory processing linked to phonological awareness (Poelmans et al, 2011).…”

From temporal processing to developmental language disorders: mind the gap

“…How satisfactory are these tasks? Although the association between phonological awareness and literacy development is well established (see Hulme & Snowling [92]), the precise nature of a phonological deficit as a causal theory of reading impairment remains vague-and is demonstrably false if taken to apply to the representation of the phonological identities of words or word parts: studies have failed to detect impaired or deficient phonological representations in tasks that require implicit use without explicit manipulation [80,93,94] or directly address phonological constraints [95]. The same observation applies to lexical stress: 'stress impairments' are observed in metalinguistic tasks involving explicit identification, comparison or manipulation of abstract stress patterns [28,31,47].…”

Brain activity patterns of phonemic representations are atypical in beginning readers with family risk for dyslexia

“…This idea is further supported by deficits observed in children with dyslexia when tested via implicit phonological tasks that are designed to tap more directly on the underlying deficient representations, such as categorical perception (see meta‐analysis of Noordenbos & Serniclaes, ), lexical gating and priming experiments (Boada & Pennington, ; Bonte & Blomert, ; Matsala, ). However, a series of similar experiments in adult university students did not find support for a problem related to the nature of phonological representations but rather supported an access problem (Ramus & Szenkovits, ; Dickie, Ota, & Clark, ). It should be acknowledged that these cognitive experiments cannot purely measure either representation or access since the measured outcome is the result of the dynamic interplay between them and deficits can be biased by attentional problems, which are often present in the dyslexic population (Hendren, Haft, Black, White, & Hoeft, ; Hong, ).…”