An access deficit or a deficit in the phonological representations themselves: What can we learn from naming errors?

ABSTRACT

Anomic aphasia is characterized by good comprehension and non-word repetition but poor naming. Two sub-types of deficits might be hypothesized: faulty access to preserved phonological representations or preserved access to impaired representations. Phonological errors may occur only when representations are impaired or in post-lexical deficits (conduction aphasia). We analysed the incidence of phonological naming errors of 30 individuals, 25 with anomic aphasia based on poor naming but good repetition and comprehension, and five with conduction aphasia based on poor naming and poor repetition. Individuals with anomic aphasia produced very few phonological errors compared to individuals with conduction aphasia (0–19.1% versus 42–66%). However, six individuals with anomia produced more than 11% phonological errors, suggesting two patterns of deficit: either impaired lexical representations or impaired access to them. The lack of phonological errors in most individuals with anomic aphasia suggests that access to the phonological output lexicon is semantically, not phonologically driven.

KEYWORDS:

• Phonological output lexicon
• post-lexical stages
• lexical retrieval
• anomic aphasia
• conduction aphasia
• phonological errors

Acknowledgements

We thank Naama Friedmann for fruitful discussions of this research and to Cristina Romani for her helpful comments on earlier versions of this paper. We also thank Kim Barkani and Hagit Shemesh for their help in data analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Note that the frequency effect has also been reported in individuals with post-lexical deficits. See, for example, Goldrick and Rapp (2007); Goldrick et al. (2010); Romani et al. (2002); Romani and Galluzzi (2005).

2 It should be noted that failure to repeat words and non-words can be ascribed either to a selective deficit in the post-lexical output levels or to deficits in the early input levels of auditory processing: auditory analysis and the phonological input buffer (Bartha & Benke, 2003; Gvion & Friedmann, 2012; Howard & Nickels, 2005; Martin & Breedin, 1992; Martin et al., 1994; and many others). Preserved recognition phonological working memory spans, as opposed to limited phonological recall memory spans (which involve both input and output levels), indicate that repetition failure results from post-lexical impairments.

3 Length effects are not expected in lexical access. However, a length effect could be present in the case of impaired phonological representations because longer words, having more phonemes, offer more opportunity for errors.

4 The SHEMESH naming test has very detailed instructions about what is considered a semantic error and what is not. Each response that could have been considered a synonym of the target word (e.g., frog-toad, pitcher-jug) was scored as a correct response. Errors such as fork-knife, sun-moon, penguin-dolphin were scored as semantically related. Responses that do not share semantic features with the target word (e.g., frog-window), which were very rarely produced, were scored as unrelated errors, or as visual errors when there was a visual resemblance between the target object and the response (e.g., fork-rake). When there was a doubt about how to classify an error, it was discussed and resolved between the authors.

5 A reviewer suggested that some types of errors, such as latencies, “no response” / “don’t know” responses, paraphrases, naming in another language or related-gesture responses, are not informative about the question at hand and suggested removing these responses from the analysis. Following the reviewer’s comment, we reanalysed the rate of errors that both groups produced, excluding these errors. We calculated the rate of each of the errors out of all the phonological, semantic, morphological, superordinate category and perseveration errors and, nevertheless, the difference between the rates of phonological errors among the individuals with CA and those with AA remained impressive: phonological errors accounted for 88% of the errors in the CA group but for only 18% of the errors in the AA group.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.