Phonological processing in dyslexic children: a study combining functional imaging and event related potentials

Georgiewa, Petra; Rzanny, R.; Gaser, Christian; Gerhard, U.-J.; Vieweg, Uta; Freesmeyer, Daniela; Mentzel, Hans Joachim; Kaiser, Werner A.; Blanz, Bernhard

doi:10.1016/s0304-3940(01)02236-4

Cited by 101 publications

(67 citation statements)

References 15 publications

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“…This result is consistent with those obtained on other explicit phonological awareness measures, most of which are in the N400 range (e.g., auditory and visual rhyming; Ackerman, Dykman, & Oglesby, 1994;McPherson & Ackerman, 1999;McPherson, Ackerman, Holcomb, & Dykman, 1998;Rüsseler, Becker, Johannes, & Münte, 2007; see also Jednoróga, Marchewkaa, Tacikowskia, & Grabowska, 2010). It is also compatible with the hypothesis that dyslexics fail to adequately develop phonological skills, as well as an under-activation of temporo-parietal areas (Georgiewa et al, 2002;Shaywitz et al, 2001; see Richlan, Kronbichler, & Wimmer, 2009, for a review) or less engagement of the left hemisphere in these readers (e.g., Araújo et al, 2012;Pugh et al, 2000;Shaywitz et al, 2001). Yet, it might be the case that these modulations of the N320 (and N400) reflect effects that are too late to index impaired perceptual sensitivity to phonology (cf., Savill & Thierry, 2011b), and therefore index something else.…”

Section: Discussionsupporting

confidence: 90%

Lexical and sublexical orthographic processing: An ERP study with skilled and dyslexic adult readers

Araújo

Faísca²,

Bramão

et al. 2015

Brain and Language

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a b s t r a c tThis ERP study investigated the cognitive nature of the P1-N1 components during orthographic processing. We used an implicit reading task with various types of stimuli involving different amounts of sublexical or lexical orthographic processing (words, pseudohomophones, pseudowords, nonwords, and symbols), and tested average and dyslexic readers. An orthographic regularity effect (pseudowords-nonwords contrast) was observed in the average but not in the dyslexic group. This suggests an early sensitivity to the dependencies among letters in word-forms that reflect orthographic structure, while the dyslexic brain apparently fails to be appropriately sensitive to these complex features. Moreover, in the adults the N1-response may already reflect lexical access: (i) the N1 was sensitive to the familiar vs. less familiar orthographic sequence contrast; (ii) and early effects of the phonological form (words-pseudohomophones contrast) were also found. Finally, the later N320 component was attenuated in the dyslexics, suggesting suboptimal processing in later stages of phonological analysis.

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Section: Discussionsupporting

confidence: 90%

Lexical and sublexical orthographic processing: An ERP study with skilled and dyslexic adult readers

Araújo

Faísca²,

Bramão

et al. 2015

Brain and Language

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“…In addition to the characteristic hypoactivation in individuals with DD, some studies have reported hyperactivity primarily in the left frontal and/or right hemispheric regions of the brain in children and adults with DD during reading-related tasks (44,49,50,63). In the present study, however, hyperactivation was not observed in children with a familial risk for DD.…”

Section: Discussioncontrasting

confidence: 68%

“…Furthermore, an increase in activation in left frontal and right lateralized anterior brain areas has been shown in individuals with DD (44,45,49,50,63). This hyperactivation seen in individuals with DD has been suggested to reflect a compensatory mechanism for the dysfunctional reading system (e.g., refs.…”

mentioning

confidence: 98%

“…Voxel-based morphometry reveals differences in gray-matter volume indices in individuals with DD (compared with typical reading controls) in various areas of the brain, including left occipitotemporal and temporoparietal areas (44,(56)(57)(58)(59)(60)(61), bilateral fusiform (59), and lingual gyrus (LG) (58) as well as the cerebellum (56-58). Morphological abnormalities in these regions can be identified even before reading skills are present in children as young as 5 to 6 y of age, suggesting atypical early development or even a genetic basis for DD (62).Furthermore, an increase in activation in left frontal and right lateralized anterior brain areas has been shown in individuals with DD (44,45,49,50,63). This hyperactivation seen in individuals with DD has been suggested to reflect a compensatory mechanism for the dysfunctional reading system (e.g., refs.…”

mentioning

confidence: 99%

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Functional characteristics of developmental dyslexia in left-hemispheric posterior brain regions predate reading onset

Raschle

Zuk²,

Gaab³

2012

Proc. Natl. Acad. Sci. U.S.A.

206

190

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Individuals with developmental dyslexia (DD) show a disruption in posterior left-hemispheric neural networks during phonological processing. Additionally, compensatory mechanisms in children and adults with DD have been located within frontal brain areas. However, it remains unclear when and how differences in posterior left-hemispheric networks manifest and whether compensatory mechanisms have already started to develop in the prereading brain. Here we investigate functional networks during phonological processing in 36 prereading children with a familial risk for DD (n = 18, average age = 66.50 mo) compared with age and IQ-matched controls (n = 18; average age = 65.61 mo). Functional neuroimaging results reveal reduced activation in prereading children with a family-history of DD (FHD + ), compared with those without (FHD − ), in bilateral occipitotemporal and left temporoparietal brain regions. This finding corresponds to previously identified hypoactivations in left hemispheric posterior brain regions for school-aged children and adults with a diagnosis of DD. Furthermore, left occipitotemporal and temporoparietal brain activity correlates positively with prereading skills in both groups. Our results suggest that differences in neural correlates of phonological processing in individuals with DD are not a result of reading failure, but are present before literacy acquisition starts. Additionally, no hyperactivation in frontal brain regions was observed, suggesting that compensatory mechanisms for reading failureare not yet present. Future longitudinal studies are needed to determine whether the identified differences may serve as neural premarkers for the early identification of children at risk for DD.is a specific learning disability that affects about 5-17% of all children (1, 2). DD is characterized by difficulties with accurate and fluent word recognition and poor spelling and decoding performance. DD cannot be accounted for by poor vision, hearing, or a lack of motivation. Molecular-genetic, twin, and family studies have shown a marked familial risk for DD, with an increasing prevalence in families with one or more members with a diagnosis of DD or reading difficulties (e.g., refs. 3 and 4). In addition, several DD susceptibility genes crucial for early brain development have been reported (5-8). DD can have severe social and psychological consequences (9-11) and may impact a child's life beyond their academic pursuits. Studies have shown that children with learning disabilities are less likely to complete high school (12) and are more likely to enter the juvenile justice system (13).Most researchers, clinicians, and reading specialists agree that DD typically results from a weakness in the ability to manipulate oral speech sounds of language (2,14). Individuals with DD are often unable to access the underlying sound structures of words, creating a difficulty in mapping sounds to written language (15-18). Phonological processing skills have been found to be a key predictor of later reading ability in pr...

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“…Some studies on reading and rhyming in adults found more left inferior frontal activation for those with dyslexia than for controls (Brunswick et al, 1999;Rumsey et al, 1997;Shaywitz et al, 1998), but others reported more activation for controls (GrossGlenn et al, 1991;Paulesu et al, 1996). Also for children the results are rather inconsistent with dyslexia leading to either more (Georgiewa et al, 2002;Temple et al, 2001) or less activation in the inferior frontal gyrus (Bolger et al, 2008b;Booth et al, 2007;Booth et al, 2008;Cao et al, 2006;Georgiewa et al, 1999;Shaywitz et al, 2002). The meta-analyses by Richlan et al summarized the local activation differences between good and poor readers in the left inferior frontal gyrus with more pronounced activity in the anterior insula and primary motor cortex close to the mouth area and underactivation in the opercular part of the inferior frontal gyrus in poor readers.…”

Section: Introductionmentioning

confidence: 98%

Early emergence of deviant frontal fMRI activity for phonological processes in poor beginning readers

et al. 2010

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Phonological processing in dyslexic children: a study combining functional imaging and event related potentials

Cited by 101 publications

References 15 publications

Lexical and sublexical orthographic processing: An ERP study with skilled and dyslexic adult readers

Lexical and sublexical orthographic processing: An ERP study with skilled and dyslexic adult readers

Functional characteristics of developmental dyslexia in left-hemispheric posterior brain regions predate reading onset

Early emergence of deviant frontal fMRI activity for phonological processes in poor beginning readers

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