Letter‐position encoding and dyslexia

“Indeed, the dual-modes account is inconsistent with brain-imaging evidence indicating that lexical access is routed through the LH, independently of presentation location (Cohen et al., 2002).”

“, [40, 41]).”

“An earlier account, which predicted but did not directly investigate letter–speech sound integration deficits in dyslexia (Whitney and Cornelissen, 2005) assumes that learning to read starts by creating ‘graphonemes’; abstract phonemic presentations linking graphemes and groups of phonetic features.”

“Regardless of how this process is exactly conceived, it clearly requires focusing of visuo-spatial attention on each sublexical unit (single letter or letter cluster), inhibiting the flanking units (Whitney & Cornelissen, 2005).”

“For instance, the time course for recognition may be different for letters in different parts of the visual span (Ortiz, 2002; Whitney, 2001; Whitney & Cornelissen, 2005) and certainly at different parts of the visual field (Lee, Legge, & Ortiz, 2003).”

“In contrast, Whitney and Cornelissen (2005) argued that difficulty encoding spatial position during reading acquisition, possibly due to an impairment of visual attention related to an M-stream deficit, explains some problems learning to read.”

“…representations per se of individuals with developmental dyslexia may be intact; see Ramus & Szenkovits, 2008) and that developmental dyslexia may be characterised on the basis of abnormal, parallel letter coding as visual objects rather than as letters (e.g., see Whitney & Cornelissen, 2005).”

“…Grainger, Granier, Farioli, Van Assche, & Van Heuven, 2006; Grainger & Van Heuven, 2003; Grainger & Whitney, 2004; Schoonbaert & Grainger, 2004; Whitney, 2001; Whitney & Berndt, 1999; Whitney & Cornelissen, 2005, 2008), and the ‘spatial-coding’ SOLAR model (Davis, 1999, 2006; Davis & Bowers, 2006).”

“In addition, Whitney and Cornelissen (2005) hypothesized that a visuo-attentional deficit impairs the encoding of spatial position during reading acquisition.”

“In Whitney and Cornelissen’s (Whitney, 2001, 2008; Whitney & Cornelissen, 2005, 2008) SERIOL (sequential encoding regulated by inputs to oscillations within letter units) model, bigrams are weighted differently according to the separation between the letter pair, and in the most recent version, the…”

“The use of high contrast alphabetic stimuli in the current study might have triggered some visual attentional processes more specifically involved in letter-string processing and reading (as postulated by Whitney & Cornelissen, 2005).”

“This coupling is taken to be a basic representational mechanism of the visual system (Whitney & Cornelissen, 2005), implying that gamma/theta co-variation should be present during both visual word and object recognition.”

“…be noted that besides reflecting a decreasing importance of serial sublexical word processing in favour of more parallel lexical processing, the developmental decrease in length effect could merely reflect an increase in efficiency of serial sublexical processing (Whitney & Cornelissen, 2005).”

“These findings have led to theoretical models that explain the link between a dorsal stream deficit and reading, including attention (Vidyasagar, 2004), ocular motor control (Stein, 2001), and letter position encoding (Whitney & Cornelissen, 2005), see Boden and Giaschi (2007) for a recent review.”

“As we indicated in the Introduction, the current version of the SERIOL model (Whitney & Cornelissen, 2005) predicts a role of phonology in transposed-letter effects via the activation of open biphones (cid:1) which would work in the same way as the open bigrams.”

“The SERIOL model assumes the presence of a phonological route that operates with biphones in the same way that the orthographic route operates with bigrams ( Whitney & Cornelissen, 2005 ), and conal and CANAL share a higher number of biphones than cinal and CANAL.”

“The end position advantage also speaks against the hypothesis of Whitney and Cornelissen (2005) that dyslexic readers lack the speciWc string processing system which in competent readers generates the end position advantage by overriding the visual acuity gradient.”

“…2004), a global change in speed of processing (Kail & Hall, 1994), a deficit in string-specific or multi-element processing (Hawelka & Wimmer, 2005; Whitney & Cornelissen, 2005; but see Hawelka & Wimmer, 2008 for a discussion of the attentional basis of these deficits) or a general working memory…”

“As we indicated in the Introduction, the current version of the SERIOL model (Whitney & Cornelissen, 2005) predicts a role of phonology in transposed-letter effects via the activation of open biphones which would work in the same way as the open bigrams.”

“Skilled readers also show letter transpositons in reading, and misperceive migratable nonwords as their transposed counterpart (Andrews, 1996; Perea and Lupker, 2004), findings that led to the development of models that accommodate encoding of letter position within strings (the SERIOL model, Whitney, 2001; Whitney an…”

“Note that at present, these models cannot accommodate the presence of phonological effects in lexical decision and normal reading (e.g., the conal-CANAL effect; see Pollatsek, Perea, & Carreiras, 2005; see Whitney & Cornelissen, 2005, for an initial expansion of the SERIOL model to phonological processing).”

“It has also been proposed that open bigrams might only be used on the lexical route of a dual-route framework, letter-sound correspondences would then be used on the nonlexical route [7].”

“…her model could account for the differences in the OVP curves reported by Brysbaert (1994) by assuming a higher inversion cost of the acuity gradient in the subdominant hemisphere, combined with an interhemispheric transfer cost of 9 msec (see also Whitney, 2004; Whitney & Lavidor, 2004, 2005).”

“Note that serial firing fulfils this requirement; positional information is encoded by the order of firing.”

“Hence,lexicalaccessfor thatentryduringreadingwillbeimpairedandnormalproceduresformappinggrapheme sequencestophonemesequencesaredisrupted(Whitney&Cornelissen,2005). nonword)asanovelsequenceofsounds,similartoasequenceofdigitsorletterstobe learnedinanimmediateserialrecalltask(orspantask).”

“…related activity could indicate a persistent neural association between orthography and phonology that is left over from learning to read – such as when using letter–sound knowledge to sound out a new word – but that no longer plays a part in visual word recognition (Whitney & Cornelissen, 2005).”

“This phoneme–grapheme binding becomes automatic for most readers by second grade, after sufficient practice and experience (Blomert, 2011; Froyen, Willems, & Blomert, 2011), resulting in a stable integrated “graphoneme” object representation (Whitney & Cornelissen, 2005).”

“However, contrary to the predictions of Whitney and Cornelissen (2005) we obtained very much the same pattern of results in the group with dyslexia (second part of Figure 3), suggesting that for the group of dyslexics that we tested, problems with the formation of the location gradient were not the…”

“The exception is the current version of the SERIOL model (see Whitney & Cornelissen , 2005), in which letter encoding is parsed into a graphosyllabic representation in which vowels and consonants would have separate slots; however, no specific predictions are made in this model for the effects of…”

“Whitney and Cornelissen (2005) recently proposed a theoretical account of the development of orthographic-information extraction from print.”

“(For conjectures on how this learning might occur, see Whitney & Cornelissen (2005) ).”

“Moreover, Whitney and Cornelissen (2005) point out difficulties in acquiring this complex position encoding mechanism as a potential source of developmental dyslexia.”

“…is proposed to lead to more extensive processing in the right hemisphere than in the left hemisphere, with hemisphere-specific processing learned during reading acquisition (see Whitney (2001); Whitney & Cornelissen (2005) and Whitney and Lavidor, 2004 for detailed exposition of the SERIOL model).”

“The absence of a significant crossmodal MMN in the synchronous condition may represent difficulties in forming a clear letter-speech sound representation (Blomert, 2011), like ‘‘graphonemes’’ (Whitney and Cornelissen, 2005).”

“More specifically, Whitney and Cornelissen (2005) propose that skilled readers encode the serial position of the letters of a word on the basis of a single visual fixation.”

“, a new representation of the speech sound that also includes its orthographic characteristic [16].”

“Thus, the external letter advantage is explained in terms of reduced lateral inhibition arising from string-specific processing, rather than from a lack of masking at a very low visual level (Whitney & Cornelissen, 2005 ).”

“However, less fluent naming may also be due to a dispersed allocation of visual attention, which leads to a reduced ability to discriminate a fixated letter from its surrounding information (Whitney & Cornelissen, 2005).”

“Yet, as with the SERIOL model of reading (Whitney & Cornelissen, 2004), the similar properties of the same word presented in different positions was discovered by the model.”

“The three prominent contenders are SOLAR (Davis, 1999 ), Open Bigram (eg, Grainger & van Heuven, 2003 ; Schoonbaert & Grainger, 2004 ) and SERIOL (Whitney, 2001 ; Whitney & Cornelissen, 2005 , 2008 ) models.”

“Interactive activation models (see Seidenberg & McClelland, 1989 ; Grainger & Jacobs, 1996 ; Coltheart et al, 2001 ; Whitney & Cornelissen, 2005 ) also provide explanations for many of the psychological characteristics of word recognition, such as word frequency effects (more common words are recognized faster) and se…”

“Understanding how the brain accomplishes this task may shed light on basic processes of visual analysis, and lead to insights into the etiology and remediation of developmental dyslexia (Whitney & Cornelissen, 2005).”

“Speech-sound dyslexia is also called peripheral or letter position dyslexia (Whitney & Cornelissen, 2005).”

“Whitney ( 2001 ) showed that her model could account for the differences in the OVP curves reported by Brysbaert ( 1994 ) by assuming a higher inversion cost of the acuity gradient in the subdominant hemisphere, combined with an interhemispheric transfer cost of 9 ms (see also Whitney, 2004 ; Whitney & Lavidor, 2004 ,…”

“For example, children in the initial stages of reading acquisition focus serially on single letters in order to link those letters to single phonemes [31].”

“This is the case with both the spatial coding model (e.g., Davis (2010) and open bigram account (e.g., Grainger & van Heuven, 2003; Grainger & Ziegler, 2011; Schoonbaert & Grainger, 2004; Whitney, 2001, 2008; Whitney & Cornelissen, 2005, 2008).”

“According to activation accounts of visual word processing (e.g., Whitney, 2001; Whitney & Berndt, 1999; Whitney & Cornelissen, 2005), the disorder can be assumed to disrupt the serial processing from the word’s initial to final letters.”

“The SERIOL model, for example, proposes that repeated attention to common letter combinations yields automatic word recognition (Whitney, 2001; Whitney & Cornelissen, 2005).”

“…for the present study was the idea that if less effective word recognisers have trouble coding the order of letters in words, as highlighted by Pammer and Vidyasagar (2005) and Whitney and Cornelissen (2005), then such a defect might partly depend on inferior memory for visual elements in general.”

“This transformation originates during reading acquisition in the form of serial shifts of attention across the letters (Boros et al., 2016; Whitney & Cornelissen, 2005).”

“Processing written language and the difficulties in visual perception of speed and motion may stem from inefficiency of, or damage to, the transient dorsal stream of the visual system which includes the magnocellular pathway and extrastriate cortex such as area V5/MT [18– 23].”

“For example, people with dyslexia were more likely to exhibit letter reversals (eg, “how” as “who”; Whitney & Cornelissen, 2005 ) when misreading, and impairment on a temporal forced-choice paradigm was only observed when information was presented sequentially rather than simultaneously (eg, Ben-Yehuda, Sackett, Malch…”

“, [4,5,9,40]).”

“Diff erent theoretical models based on these fi ndings have been proposed to explain the relation between dorsal defi cit, reading, attention, ocular motor control, and letter coding ( Vidyasagar, 2004 ; Whitney & Cornelissen, 2005 ; Boden & Giaschi, 2007 ).”