Computational modelling of phonological dyslexia: how does the DRC model fare?

Lyndsey Nickels, Britta Biedermann, Max Coltheart, Steve Saunders, Jeremy J. Tree

Research output: Contribution to journalArticleResearchpeer-review

Abstract

This paper investigates the patterns of reading impairment in phonological dyslexia using computational modelling with the dual-route cascaded model of reading (DRC, Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). Systematic lesioning of nonlexical and phonological processes in DRC demonstrates that different lesions and severity of those lesions can reproduce features of phonological dyslexia including impaired reading of nonwords, relatively spared reading of words, an advantage for reading pseudohomophones. Using the same stimuli for model and for patients, lesions to DRC were also used to simulate the reading accuracy shown by three individuals with acquired phonological dyslexia. No single lesion could replicate the reading performance of all three individuals. In order to simulate reading accuracy for one individual a phonological impairment was necessary (addition of noise to the phoneme units), and for the remaining two individuals an impairment to nonlexical reading procedures (increasing the time interval between each new letter being processed) was necessary. We argue that no single locus of impairment (neither phonological nor nonlexical) can account for the reading impairments of all individuals with phonological dyslexia. Instead, different individuals have different impairments (and combinations of impairments) that together provide the spectrum of patterns found in phonological dyslexia.

LanguageEnglish
Pages165-193
Number of pages29
JournalCognitive Neuropsychology
Volume25
Issue number2
DOIs
Publication statusPublished - Mar 2008

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Dyslexia
Reading
Articulation Disorders
Acquired Dyslexia
Computational Modeling
Noise
Impairment

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title = "Computational modelling of phonological dyslexia: how does the DRC model fare?",
abstract = "This paper investigates the patterns of reading impairment in phonological dyslexia using computational modelling with the dual-route cascaded model of reading (DRC, Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). Systematic lesioning of nonlexical and phonological processes in DRC demonstrates that different lesions and severity of those lesions can reproduce features of phonological dyslexia including impaired reading of nonwords, relatively spared reading of words, an advantage for reading pseudohomophones. Using the same stimuli for model and for patients, lesions to DRC were also used to simulate the reading accuracy shown by three individuals with acquired phonological dyslexia. No single lesion could replicate the reading performance of all three individuals. In order to simulate reading accuracy for one individual a phonological impairment was necessary (addition of noise to the phoneme units), and for the remaining two individuals an impairment to nonlexical reading procedures (increasing the time interval between each new letter being processed) was necessary. We argue that no single locus of impairment (neither phonological nor nonlexical) can account for the reading impairments of all individuals with phonological dyslexia. Instead, different individuals have different impairments (and combinations of impairments) that together provide the spectrum of patterns found in phonological dyslexia.",
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Computational modelling of phonological dyslexia : how does the DRC model fare? / Nickels, Lyndsey; Biedermann, Britta; Coltheart, Max; Saunders, Steve; Tree, Jeremy J.

In: Cognitive Neuropsychology, Vol. 25, No. 2, 03.2008, p. 165-193.

Research output: Contribution to journalArticleResearchpeer-review

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