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Karalyn Patterson - One of the best experts on this subject based on the ideXlab platform.
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SD-Squared: On the Association Between Semantic Dementia
2015Co-Authors: Surface Dyslexia, Anna M. Woollams, David C. Plaut, Matthew Lambon A. Ralph, Karalyn PattersonAbstract:Within the connectionist triangle model of reading aloud, interaction between semantic and phonological representations occurs for all words but is particularly important for correct pronunciation of lower frequency exception words. This framework therefore predicts that (a) semantic dementia, which compromises semantic knowledge, should be accompanied by Surface Dyslexia, a frequency-modulated deficit in exception word reading, and (b) there should be a significant relationship between the severity of semantic degradation and the severity of Surface Dyslexia. The authors evaluated these claims with reference to 100 observations of reading data from 51 cases of semantic dementia. Surface Dyslexia was rampant, and a simple composite semantic measure accounted for half of the variance in low-frequency exception word reading. Although in 3 cases initial testing revealed a moderate semantic impairment but normal exception word reading, all of these became Surface dyslexic as their semantic knowledge deteriorated further. The connectionist account attributes such cases to premorbid individual variation in semantic reliance for accurate exception word reading. These results provide a striking demonstration of the association between semantic dementia and Surface Dyslexia, a phenomenon that the authors have dubbed SD-squared
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SD-squared 1 RUNNING HEAD: SEMANTIC DEMENTIA AND Surface Dyslexia SD-SQUARED: ON THE ASSOCIATION BETWEEN SEMANTIC
2014Co-Authors: Surface Dyslexia, Anna M. Woollams, David C. Plaut, Matthew Lambon A. Ralph, Karalyn PattersonAbstract:Within the connectionist triangle model of reading aloud, interaction between semantic and phonological representations occurs for all words but is particularly important for correct pronunciation of lower-frequency exception words. This framework therefore predicts that (a) semantic dementia, which compromises semantic knowledge, should be accompanied by Surface Dyslexia, a frequencymodulated deficit in exception word reading; and (b) there should be a significant relationship between the severity of semantic dementia and of Surface Dyslexia. We evaluated these claims with reference to 100 observations of reading data from 51 cases of semantic dementia. Surface Dyslexia was rampant, and a simple composite semantic measure accounted for more than half of the variance in low-frequency exception word reading. These results provide a striking demonstration of the association between semantic dementia (SD) and Surface Dyslexia (SD), a phenomenon that we have dubbed SD-squared
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SD-Squared Revisited: Reply to Coltheart, Tree, and Saunders (2010)
Psychological Review, 2010Co-Authors: Anna M. Woollams, Matthew A. Lambon Ralph, David C. Plaut, Karalyn PattersonAbstract:The connectionist triangle model of reading aloud proposes that semantic activation of phonology is particularly important for correct pronunciation of low-frequency exception words. Our consideration of this issue (Woollams, Lambon Ralph, Plaut, & Patterson, 2007) reported computational simulations demonstrating that reduction and disruption of this semantic activation resulted in the marked deficit in low-frequency exception word reading that is characteristic of Surface Dyslexia. We then presented 100 observations of reading aloud from 51 patients with semantic dementia (SD) demonstrating a universal decline into Surface Dyslexia, a phenomenon we termed “SD-squared.” Coltheart, Tree, and Saunders (2010) have more recently provided a simulation of the SD-squared data within the dual route cascaded (DRC) model, achieved by varying the amount of damage to components of the lexical and nonlexical pathways. Although they suggested that these simulations provide a closer fit to the SD patients’ reading data than our own, we demonstrate here that this is not the case. Moreover, we argue that the connectionist triangle model account has substantially greater explanatory and predictive power than the DRC account.
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The association between semantic dementia and Surface Dyslexia in Japanese.
Neuropsychologia, 2009Co-Authors: Takao Fushimi, Matthew A. Lambon Ralph, Kenjiro Komori, Manabu Ikeda, Karalyn PattersonAbstract:One theory about reading suggests that producing the correct pronunciations of written words, particularly less familiar words with an atypical spelling-sound relationship, relies in part on knowledge of the word's meaning. This hypothesis has been supported by reports of Surface Dyslexia in large case-series studies of English-speaking/reading patients with semantic dementia (SD), but would have increased credibility if it applied to other languages and writing systems as well. The hypothesis predicts that, of the two systems used to write Japanese, SD patients should be unimpaired at oral reading of kana because of its invariant relationship between orthography and phonology. By contrast, oral reading of kanji should be impaired in a graded fashion depending on the consistency characteristics of the kanji target words, with worst performance on words whose component characters take 'minority' (atypical) pronunciations, especially if the words are of lower frequency. Errors in kanji reading should primarily reflect assignment of more typical readings to the component characters in these atypical words. In the largest-ever-reported case series of Japanese patients with semantic dementia, we tested and confirmed this hypothesis.
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SD-squared: On the association between semantic dementia and Surface Dyslexia
Psychological Review, 2007Co-Authors: Anna M. Woollams, Matthew A. Lambon Ralph, David C. Plaut, Karalyn PattersonAbstract:Within the connectionist triangle model of reading aloud, interaction between semantic and phonological representations occurs for all words but is particularly important for correct pronunciation of lower frequency exception words. This framework therefore predicts that (a) semantic dementia, which compromises semantic knowledge, should be accompanied by Surface Dyslexia, a frequency-modulated deficit in exception word reading, and (b) there should be a significant relationship between the severity of semantic degradation and the severity of Surface Dyslexia. The authors evaluated these claims with reference to 100 observations of reading data from 51 cases of semantic dementia. Surface Dyslexia was rampant, and a simple composite semantic measure accounted for half of the variance in low-frequency exception word reading. Although in 3 cases initial testing revealed a moderate semantic impairment but normal exception word reading, all of these became Surface dyslexic as their semantic knowledge deteriorated further. The connectionist account attributes such cases to premorbid individual variation in semantic reliance for accurate exception word reading. These results provide a striking demonstration of the association between semantic dementia and Surface Dyslexia, a phenomenon that the authors have dubbed SD-squared.
Saghie Sharifzadeh - One of the best experts on this subject based on the ideXlab platform.
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does Surface Dyslexia dysgraphia relate to semantic deficits in the semantic variant of primary progressive aphasia
Neuropsychologia, 2019Co-Authors: Marc Teichmann, Clara Sanches, Julia Moreau, Sophie Ferrieux, Marie Nogues, Bruno Dubois, Meggane Cacouault, Saghie SharifzadehAbstract:Abstract The semantic variant of primary progressive aphasia (sv-PPA) is a degenerative condition which causes Surface Dyslexia/dysgraphia, resulting in reading/writing errors of irregular words with non-transparent grapheme-to-phoneme correspondences (e.g., ‘plaid’) as opposed to regular words (e.g., ‘cat’). According to connectionist models, most authors have attributed this deficit to semantic impairments, but this assumption is at odds with symbolic models, such as the DRC account, stating that the reading/writing of irregulars relies on the mental lexicon. Our study investigated whether sv-PPA affects the lexicon in addition to the semantic system, and whether semantic or lexical deficits cause Surface Dyslexia/dysgraphia, while challenging the two major models of written language. We explored a cohort of 12 sv-PPA patients and 25 matched healthy controls using a reading and writing task, a semantic task (category decision: living vs. non-living), and a lexical task (lexical decision: word vs. no-neighbor non-word). Correlation analyses were conducted to assess the relationship between reading/writing scores of irregulars and semantic vs. lexical performance. Furthermore, item-by-item analyses explored the consistency of reading/writing errors with item-specific semantic and lexical errors. Results showed that sv-PPA patients are impaired at reading and writing irregular words, and that they have impaired performance in both the semantic and the lexical task. Reading/writing scores with irregulars correlated significantly with performance in the lexical but not the semantic task. Item-by-item analyses revealed that failure in the lexical task on a given irregular word is a good predictor of reading/writing errors with that item (positive predictive value: 77.5%), which was not the case for the semantic task (positive predictive value: 42.5%). Our findings show that sv-PPA is not restricted to semantic damage but that it also comprises damage to the mental lexicon, which appears to be the major factor for Surface Dyslexia/dysgraphia. Our data support symbolic models whereas they challenge connectionist accounts.
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Does Surface Dyslexia/dysgraphia relate to semantic deficits in the semantic variant of primary progressive aphasia?
Neuropsychologia, 2019Co-Authors: Marc Teichmann, Clara Sanches, Julia Moreau, Sophie Ferrieux, Marie Nogues, Bruno Dubois, Meggane Cacouault, Saghie SharifzadehAbstract:Abstract The semantic variant of primary progressive aphasia (sv-PPA) is a degenerative condition which causes Surface Dyslexia/dysgraphia, resulting in reading/writing errors of irregular words with non-transparent grapheme-to-phoneme correspondences (e.g., ‘plaid’) as opposed to regular words (e.g., ‘cat’). According to connectionist models, most authors have attributed this deficit to semantic impairments, but this assumption is at odds with symbolic models, such as the DRC account, stating that the reading/writing of irregulars relies on the mental lexicon. Our study investigated whether sv-PPA affects the lexicon in addition to the semantic system, and whether semantic or lexical deficits cause Surface Dyslexia/dysgraphia, while challenging the two major models of written language. We explored a cohort of 12 sv-PPA patients and 25 matched healthy controls using a reading and writing task, a semantic task (category decision: living vs. non-living), and a lexical task (lexical decision: word vs. no-neighbor non-word). Correlation analyses were conducted to assess the relationship between reading/writing scores of irregulars and semantic vs. lexical performance. Furthermore, item-by-item analyses explored the consistency of reading/writing errors with item-specific semantic and lexical errors. Results showed that sv-PPA patients are impaired at reading and writing irregular words, and that they have impaired performance in both the semantic and the lexical task. Reading/writing scores with irregulars correlated significantly with performance in the lexical but not the semantic task. Item-by-item analyses revealed that failure in the lexical task on a given irregular word is a good predictor of reading/writing errors with that item (positive predictive value: 77.5%), which was not the case for the semantic task (positive predictive value: 42.5%). Our findings show that sv-PPA is not restricted to semantic damage but that it also comprises damage to the mental lexicon, which appears to be the major factor for Surface Dyslexia/dysgraphia. Our data support symbolic models whereas they challenge connectionist accounts.
J. Richard Hanley - One of the best experts on this subject based on the ideXlab platform.
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Developmental Surface dysgraphia without Surface Dyslexia
Cognitive Neuropsychology, 2018Co-Authors: J. Richard Hanley, Andreas SotiropoulosAbstract:The case is reported of an individual (N.K.) with a developmental spelling impairment (dysgraphia) who has no apparent problems in reading. His performance therefore provides further evidence of a classical dissociation between impaired spelling and preserved reading in individuals with developmental literacy problems. The dissociation is observed when N.K. is asked to read and spell in either his first (Greek) or his second language (English). An investigation of his spelling performance revealed that his impairment was more selective than that of P.J.T. Although his spelling of regular words and nonwords was normal, N.K. had a problem in spelling words with atypical sound-letter associations despite having no problems in reading aloud or understanding the meaning of words of this kind. It is argued that N.K.'s pattern of performance can be best explained in terms of normal development of an orthographic system that allows access to the meaning and pronunciation of written words during reading. In terms of a dual-route model of spelling, his poor spelling appears to be the result of a developmental impairment that impedes access to the orthographic system from phonology and semantics. In terms of the triangle model, his poor spelling appears to be the result of a developmental impairment that affects activation of orthography from semantics.
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Is There Just One Dyslexic Reader? Evidence for the Existence of Distinct Dyslexic Sub-Groups
Current Developmental Disorders Reports, 2017Co-Authors: J. Richard HanleyAbstract:Purpose of Review It is generally agreed that there are individual differences in the severity of the reading deficit in Dyslexia. The purpose of this review is to discuss whether recent research strengthens claims that there are also qualitative differences in the type of reading impairment that individual dyslexic children experience. Recent Findings Recent research suggests that Surface Dyslexia exists in larger numbers than has previously been assumed and that different subtypes of Surface Dyslexia exist in English as well as in Hebrew. Bilinguals with Surface Dyslexia in English also show the hallmarks of Surface Dyslexia when reading a more transparent orthography. The developmental reading impairments that have been observed in children with phonological Dyslexia and in children with letter position Dyslexia can also be found in several different orthographies and are quite distinct from those seen in Surface Dyslexia. Summary Surface Dyslexia, phonological Dyslexia, and letter position Dyslexia represent qualitatively different types of developmental reading impairments and can all be seen in both opaque and more transparent alphabetic orthographies.
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Developmental Surface and phonological Dyslexia in both Greek and English.
Cognition, 2017Co-Authors: Andreas Sotiropoulos, J. Richard HanleyAbstract:Abstract The hallmark of developmental Surface Dyslexia in English and French is inaccurate reading of words with atypical spelling-sound correspondences. According to Douklias, Masterson and Hanley (2009), Surface Dyslexia can also be observed in Greek (a transparent orthography for reading that does not contain words of this kind). Their findings suggested that Surface Dyslexia in Greek can be characterized by slow reading of familiar words, and by inaccurate spelling of words with atypical sound-spelling correspondences (Greek is less transparent for spelling than for reading). In this study, we report seven adult cases whose slow reading and impaired spelling accuracy satisfied these criteria for Greek Surface Dyslexia. When asked to read words with atypical grapheme-phoneme correspondences in English (their second language), their accuracy was severely impaired. A co-occurrence was also observed between impaired spelling of words with atypical phoneme-grapheme correspondences in English and Greek. These co-occurrences provide strong evidence that Surface Dyslexia genuinely exists in Greek and that slow reading of real words in Greek reflects the same underlying impairment as that which produces inaccurate reading of atypical words in English. Two further individuals were observed with impaired reading and spelling of nonwords in both languages, consistent with developmental phonological Dyslexia. Neither of the phonological dyslexics read words slowly. In terms of computational models of reading aloud, these findings suggest that slow reading by dyslexics in transparent orthographies is the consequence of a developmental impairment of the lexical (Coltheart, Rastle, Perry, Langdon, & Zeigler, 2001; Perry, Ziegler, & Zorzi, 2010) or semantic reading route (Plaut, McClelland, Seidenberg, & Patterson, 1996). This outcome provides evidence that the neurophysiological substrate(s) that support the lexical/semantic and the phonological pathways that are involved in reading and spelling are the same in both Greek and English.
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Surface developmental Dyslexia is as prevalent as phonological Dyslexia when appropriate control groups are employed
Cognitive Neuropsychology, 2015Co-Authors: Dean P Wybrow, J. Richard HanleyAbstract:Previous investigations of the incidence of developmental Surface and phonological Dyslexia using reading-age-matched control groups have identified many more phonological dyslexics (poor nonword reading relative to irregular-word reading) than Surface dyslexics (poor irregular-word reading relative to nonword reading). However, because the measures that have been used to estimate reading age include irregular-word reading ability, they appear inappropriate for assessing the incidence of Surface Dyslexia. The current study used a novel method for generating control groups whose reading ability was matched to that of the dyslexic sample. The incidence of Surface Dyslexia was assessed by comparing dyslexic performance with that of a control group who were matched with the dyslexics on a test of nonword reading. The incidence of phonological Dyslexia was assessed with reference to a control group who were matched with the dyslexics at irregular-word reading. These control groups led to the identification of an approximately equal number of children with Surface and phonological Dyslexia. It appeared that selecting control participants who were matched with dyslexics for reading age led to the recruitment of individuals with relatively high nonword reading scores relative to their irregular-word reading scores compared with other types of control group. The theoretical implications of these findings are discussed.
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Stress errors in a case of developmental Surface Dyslexia in Filipino
Cognitive Neuropsychology, 2014Co-Authors: Katrina May Dulay, J. Richard HanleyAbstract:This paper reports the case of a dyslexic boy (L.A.) whose impaired reading of Filipino is consistent with developmental Surface Dyslexia. Filipino has a transparent alphabetic orthography with stress typically falling on the penultimate syllable of multisyllabic words. However, exceptions to the typical stress pattern are not marked in the Filipino orthography. L.A. read words with typical stress patterns as accurately as controls, but made many more stress errors than controls when reading Filipino words with atypical stress. He regularized the pronunciation of many of these words by incorrectly placing the stress on the penultimate syllable. Since he also read nonwords as accurately and quickly as controls and performed well on tests of phonological awareness, L.A. appears to present a clear case of developmental Surface Dyslexia in a transparent orthography.
Linda Cupples - One of the best experts on this subject based on the ideXlab platform.
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thinking outside the boxes using current reading models to assess and treat developmental Surface Dyslexia
Neuropsychological Rehabilitation, 2017Co-Authors: Linda CupplesAbstract:Improving the reading performance of children with developmental Surface Dyslexia has proved challenging, with limited generalisation of reading skills typically reported after intervention. The aim of this study was to provide tailored, theoretically motivated intervention to two children with developmental Surface Dyslexia. Our objectives were to improve their reading performance, and to evaluate the utility of current reading models in therapeutic practice. Detailed reading and cognitive profiles for two male children with developmental Surface Dyslexia were compared to the results obtained by age-matched control groups. The specific area of single-word reading difficulty for each child was identified within the dual route model (DRM) of reading, following which a theoretically motivated intervention programme was devised. Both children showed significant improvements in single-word reading ability after training, with generalisation effects observed for untrained words. However, the assessment and int...
Max Coltheart - One of the best experts on this subject based on the ideXlab platform.
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Variations within a subtype: Developmental Surface Dyslexias in English.
Cortex, 2018Co-Authors: Saskia Kohnen, Max Coltheart, Lyndsey Nickels, Leonie Geigis, Genevieve Mcarthur, Anne CastlesAbstract:Abstract Surface Dyslexia is characterised by poor reading of irregular words while nonword reading can be completely normal. Previous work has identified several theoretical possibilities for the underlying locus of impairment in Surface Dyslexia. In this study, we systematically investigated whether children with Surface Dyslexia showed different patterns of reading performance that could be traced back to different underlying levels of impairment. To do this, we tested 12 English readers, replicating previous work in Hebrew (Gvion & Friedmann, 2013; 2016; Friedmann & Lukov, 2008; Friedmann & Gvion, 2016). In our sample, we found that poor irregular word reading was associated with deficits at the level of the orthographic input lexicon and with impaired access to meaning and spoken word forms after processing written words in the orthographic input lexicon. There were also children whose Surface Dyslexia seemed to be caused by impairments of the phonological output lexicon. We suggest that further evidence is required to unequivocally support a fourth pattern where the link between orthography and meaning is intact while the link between orthography and spoken word forms is not functioning. All patterns found were consistent with dual route theory while possible patterns of results, which would be inconsistent with dual route theory, were not detected.
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Prefixes repel stress in reading aloud: Evidence from Surface Dyslexia
Cortex, 2016Co-Authors: Maria Ktori, Max Coltheart, Jeremy J. Tree, Petroula Mousikou, Kathleen RastleAbstract:This study examined the importance of prefixes as sublexical cues for stress assignment during reading aloud English disyllabic words. In particular, we tested the hypothesis that prefixes repel stress (Rastle & Coltheart, 2000) by investigating the likelihood with which patients with Surface Dyslexia assign second-syllable stress to prefixed words. Five such patients were presented with three types of disyllabic words for reading aloud: 'regular' prefixed words with weak-strong stress pattern (e.g., remind); 'irregular' prefixed words with strong-weak stress pattern (e.g., reflex); and non-prefixed words with strong-weak stress pattern (e.g., scandal). Results showed that all five patients frequently regularized the strong-weak prefixed words by pronouncing them with second syllable stress. These regularization errors provide strong evidence for the functional role of prefixes in stress assignment during reading. Additional computational simulations using the rule-based algorithm for pronouncing disyllables developed by Rastle and Coltheart (2000) and the CDP++ model of reading aloud (Perry et al., 2010) allowed us to evaluate how these two opponent approaches to reading aloud fare in respect of the patient data.
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Semantic impairment with and without Surface Dyslexia: Implications for models of reading
Cognitive Neuropsychology, 2005Co-Authors: Angela M. Blazely, Max Coltheart, Barney J. CaseyAbstract:The two best-developed computational models of reading aloud, the DRC model of Coltheart and colleagues and the connectionist attractor model of Plaut and colleagues, offer very different views about the degree to which semantic knowledge is involved in lexical processing, and hence make differing predictions about how semantic impairment (as seen, for example, in semantic dementia) will impact on lexical processing in clinical cases. Two cases meeting the criteria for semantic dementia, PC and EM, were given a battery of tests comprising comprehension tasks, a reading task, and a visual word recognition (lexical decision) task. All tasks used the same target words allowing cross-test and cross-patient comparisons. Both cases showed significant impairment of semantic memory, and word comprehension was found to be related to the word frequency of the target words. PC demonstrated poor reading of irregular words, with a Surface dyslexic pattern of reading aloud, and he performed poorly on the visual lexical decision task. His ability to read irregular words was related to their frequency and to his ability to comprehend them. In contrast, his visual lexical decision performance was not reliably influenced by his comprehension of the same words or by their frequency. EM demonstrated essentially perfect reading aloud of irregular words and essentially perfect visual lexical decision, despite her severe semantic impairment. The pattern of performance shown by EM is consistent with the DRC model of reading, but inconsistent with the connectionist attractor model and with the view, associated with that model, that orthographic and phonological processes cannot remain intact when semantic representations are degraded.
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Surface Dyslexia and Surface Dysgraphia: Treatment Studies and Their Theoretical Implications
Cognitive Neuropsychology, 1996Co-Authors: Brendan S. Weekes, Max ColtheartAbstract:We report studies of a patient with acquired Surface Dyslexia and dysgraphia. His reading impairment was treated using the methods previously reported to be successful for Surface Dyslexia by Byng and Coltheart (1986); these methods were also successful with our patient. In addition, we observed, as Byng and Coltheart did, that when these methods are used there is incomplete but significant generalisation to the reading of untreated words. Connectionist simulations of the effects of damage to the language processing system have taken this generalisation effect to be evidence that words are represented in a distributed fashion in that system ; we challenge this inference, on the basis of data from our and Byng and Coltheart's patient. Our patient's spelling impairment was treated using the methods previously reported to be successful for Surface dysgraphia by Behrmann (1987); these methods were also successful for our patient, and we found in addition, as did Behrmann, that the treatment effects upon spell...
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Cognitive Correlates of Developmental Surface Dyslexia: A Single Case Study.
Cognitive Neuropsychology, 1996Co-Authors: Anne Castles, Max ColtheartAbstract:Recently, there have been several reports of developmental analogues of the specific orthographic processing deficits observed in acquired Surface dyslexics (Goulandris & Snow ling, 1991; Hanley, Hastie, & Kay, 1992). How ever, very little has been discovered about w hat basic cognitive deficits might be associated w ith this particular kind of reading disorder. This paper describes the case of MI, a 10-year-old boy w ith a high IQ and no known history of neurological impairment. He demonstrates extremely poor performance for his age and reading level on irregular word reading tasks, but performs normally on nonword and regular word tasks. His performance on a series of homophone selection tasks suggests an impairment at the orthographic input level. The results of various tests of associated cognitive abilities conducted on MI suggest that this impairment is not associated either with phonological awareness deficits or with the visual memory problems proposed by Goulandris and Snowling (1991).
