A Principled Relation between Reading and Naming in Acquired and Developmental Anomia: Surface Dyslexia Following Impairment in the Phonological Output Lexicon

Abstract

Lexical retrieval and reading aloud are often viewed as two separate processes. However, they are not completely separate—they share components. This study assessed the effect of an impairment in a shared component, the phonological output lexicon, on lexical retrieval and on reading aloud. Because the phonological output lexicon is part of the lexical route for reading, individuals with an impairment in this lexicon may be forced to read aloud via the sublexical route and therefore show a reading pattern that is typical of surface dyslexia. To examine the effect of phonological output lexicon deficit on reading, we tested the reading of 16 Hebrew-speaking individuals with phonological output lexicon anomia, eight with acquired anomia following brain damage and eight with developmental anomia. We established that they had a phonological output lexicon deficit according to the types of errors and the effects on their naming in a picture naming task, and excluded other deficit loci in the lexical retrieval process according to a line of tests assessing their picture and word comprehension, word and non-word repetition, and phonological working memory. After we have established that the participants have a phonological output lexicon deficit, we tested their reading. To assess their reading and type of reading impairment, we tested their reading aloud, lexical decision, and written word comprehension. We found that all of the participants with phonological output lexicon impairment showed, in addition to anomia, also the typical surface dyslexia errors in reading aloud of irregular words, words with ambiguous conversion to phonemes, and potentiophones (words like “now” that, when read via the sublexical route, can be sounded out as another word, “know”). Importantly, the participants performed normally on pseudohomophone lexical decision and on homophone/potentiophone reading comprehension, indicating spared orthographic input lexicon and spared access to it and from it to lexical semantics. This pattern was shown both by the adults with acquired anomia and by the participants with developmental anomia. These results thus suggest a principled relation between anomia and dyslexia, and point to a distinct type of surface dyslexia. They further show the possibility of good comprehension of written words when the phonological output stages are impaired.

Lexical decision performance in developmental surface dysgraphia: Evidence for a unitary orthographic system that is used in both reading and spelling

“…Their impaired accuracy and speed, and the type of errors that they made are similar to the developmental surface dyslexic participants reported by Gvion and Friedmann (2016). It therefore appears that AH and GM make regularisation errors when reading aloud irregular words because the lexical route is disrupted by a problem that is associated with the phonological output lexicon.…”

“…Their poor reading of irregular words is instead caused by impaired development of the direct connection from the orthographic lexicon to the phonological lexicon (although, if so, it is surprising that these individuals could not read irregular words aloud via the semantic system). Finally, Gvion and Friedmann (2016) also observed impaired reading aloud of irregular words in Hebrew in eight developmental cases with preserved access to the meaning of written words but poor picture naming. Consequently, Gvion and Friedmann claimed that a problem at the level of the phonological lexicon can also make it necessary for individuals to read via the non-lexical route and show a pattern that is consistent with surface dyslexia.…”

“…The present study investigates their performance on tests of orthographic lexical decision (Experiment 1), on a test of semantic access from written words (Experiment 2), and on written (Experiment 3) and spoken picture-naming tests (Experiment 4). In so doing, we attempt to accommodate their reading and spelling performance in English and Greek within the theoretical framework that Friedmann and Lukov (2008) and Gvion and Friedmann (2016) devised in order to explain surface dyslexia in Hebrew. In particular, we examine whether, consistent with the DRC-SLA model that is presented in Figure 1, the performance of all seven can be explained without the need to postulate the existence of separate orthographic lexicons for reading and spelling.…”

“…In Experiment 4, we investigate further the reason why AH and GM are poor at reading and spelling irregular words to dictation given their preserved ability to make lexical decisions and semantic decisions about written words (Experiments 1 and 2). One possibility is that these two individuals have an anomic impairment of the kind that was described by Gvion and Friedmann (2016). Although they appear to have an intact orthography-semantic reading route that allows good performance on lexical decision tasks and on semantic decision tasks, they may have a developmental impairment that prevents them from activating the representations of familiar words in the phonological output lexcion.…”

“…Ellis & Young, 1988;Ellis, Lambon Ralph, Morris & Hunter, 2000). More recently, Friedmann and Lukov, (2008) and Gvion and Friedmann (2016) have suggested that different types of underlying impairment can also be observed in developmental surface dyslexia in Hebrew, a semitic language with a relatively opaque alphabetic orthography. Some of the developmental surface dyslexics studied by Friedmann and Lukov performed badly at written lexical decision, consistent with an impairment to the development of the orthographic lexicon itself.…”