Disentangling the Web: Neologistic Perseverative Errors in Jargon Aphasia

Abstract

This article explores the relationship between the neologisms and perseverative errors produced by KVH, a man with severe neologistic jargon aphasia. Detailed examination of KVH's level of language processing breakdown revealed mild difficulties with phonological encoding and severe difficulties accessing the lexical form of the word. Many of KVH's neologisms contained phonemes perseverated from previous neologisms, suggesting an integral relationship between the production of neologisms and the perseveration of phonemes. Furthermore, KVH's patterns of whole word (total) and phonological (blended) perseverations reflected his proposed underlying language processing deficits, consistent with recent literature on perseveration (e.g., Cohen and Dehaene, 1998). However, the simple binary distinction of total and blended perseveration is proposed to be somewhat limited for understanding the underlying nature of KVH's complex neologistic errors. Possible explanations regarding the mechanisms underlying the production of KVH's neologistic and perseverative errors also are discussed.

Acknowledgements

We express our greatest appreciation to the late KVH for his enthusiasm and many hours of hard work. We would like to thank Professor David Howard for his statistical support in this article, and Karalyn Patterson and anonymous reviewers for their helpful comments on earlier versions of this paper. During the preparation of this article, Dr. Lyndsey Nickels was funded by an Australian Research Council QE2 Fellowship.

Notes

¹ While some authors also have suggested that neologisms could be the result of a permanently and severely corrupted lexical representation, in some theories the distinction between phonological storage and encoding is not maintained (e.g., Dell, 1986), while in others such an impairment would result in a semantic error rather than phonological (e.g., Nickels, 2000). Indeed it is hard to conceive quite how such an impairment might be implemented computationally and, hence, we do not discuss it further in this article, but rather focus on the well-accepted phonological encoding account.

² Aphasia may seem a surprising symptom of a basal ganglia infarct; however, nonthalamic subcortically originating aphasias have been found to present similarly to cortical aphasias (e.g., Nadeau and Gonzalez-Rothi, 2001).

³ When phonologically-related and correct responses were combined, the difference in performance between regular and irregular words approached significance (Fisher Exact Test, p = .096).

⁴ As only the initial response attempts were coded the accuracy of coding is not affected by subsequent rejections of errors.

⁵ We recognize alternative accounts where no separate lexical and sublexical routes are specified for reading aloud or repetition. Rather, there is a single source of phonological representation, and the degree to which this is activated is dependent on the mapping from different stimulus modalities and the degree of transparency (e.g., see Patterson et al., 1998). However, we argue that both accounts would predict the same net effect on KVH's error patterns across the different language tasks.

⁶ As they accounted for only 3 percent (8/261) of all of KVH's blended perseverative errors, semantically related blended perseverative errors are not discussed.

⁷ It is important to note that this frequency or long-term cumulative priming-based account is different from the short-term priming account of total perseverations rejected above (see discussion of Dell et al., 1997.) Most theories make the distinction between the two.