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What lies beneath: A comparison of reading aloud in pure alexia and semantic dementia

Woollams, AM, Hoffman, P, Roberts, DJ, Ralph, MAL and Patterson, KE (2014) What lies beneath: A comparison of reading aloud in pure alexia and semantic dementia. COGNITIVE NEUROPSYCHOLOGY, 31 (5-6). pp. 461-481. ISSN 0264-3294

Woollams, Hoffman, Roberts, Lambon Ralph, Patterson. 2014. What lies beneath.pdf - Accepted Version

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Exaggerated effects of word length upon reading aloud performance define Pure Alexia, but have also been observed in Semantic Dementia. Some researchers have proposed a reading specific account, whereby performance in these two disorders reflects the same cause: impaired orthographic processing. In contrast, according to the primary systems view of acquired reading disorders, Pure Alexia results from a basic visual processing deficit, whereas degraded semantic knowledge undermines reading performance in Semantic Dementia. To explore the source of reading deficits in these two disorders, we compared the reading performance of 10 Pure Alexic and 10 Semantic Dementia patients, matched in terms of overall severity of reading deficit. The results revealed comparable frequency effects on reading accuracy, but weaker effects of regularity in Pure Alexia than Semantic Dementia. Analysis of error types revealed a higher rate of letter-based errors and a lower rate of regularisation responses in Pure Alexia than Semantic Dementia. Error responses were most often words in Pure Alexia but most often nonwords in Semantic Dementia. Although all patients made some letter substitution errors, these were characterised by visual similarity in Pure Alexia and phonological similarity in Semantic Dementia. Overall, the data indicate
that the reading deficits in Pure Alexia and Semantic Dementia arise from impairments of
visual processing and knowledge of word meaning, respectively. The locus and mechanisms
of these impairments are placed within the context of current connectionist models of

Item Type: Article
Additional Information: This is an Accepted Manuscript of an article published by Taylor & Francis in Cognitive Neuropsychology on 7 April 2014, available online: http://dx.doi.org/10.1080/02643294.2014.882300
Uncontrolled Keywords: 1109 Neurosciences, 1701 Psychology, 1702 Cognitive Science
Subjects: R Medicine > R Medicine (General)
Divisions: Natural Sciences & Psychology (closed 31 Aug 19)
Related URLs:
Date Deposited: 25 Feb 2015 10:28
Last Modified: 04 Sep 2021 14:40
DOI or ID number: 10.1080/02643294.2014.882300
URI: https://researchonline.ljmu.ac.uk/id/eprint/476
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