Similarities and Differences Between Perseverative and Non-Perseverative Errors in Aphasia: Theoretical and Clinical Implications

Abstract

Researchers have learned much about the cognitive organization of the language system by studying speech errors made by speakers with and without aphasia. Some aspects of errors made in language production reflect linguistic properties of language (e.g., linguistic similarities between an intended word and the word that was produced in error). Other aspects reflect processes that enable production of language (e.g., substitutions or sequencing errors). A particularly intriguing class of error is perseveration, the unintended retrieval of words or sounds after they have been recently produced. Although the occurrence of perseverations is influenced by both linguistic and processing aspects of language production, these errors have been particularly instructive about the latter aspect. Martin and Dell (2007) proposed that word and sound perseverations result from the same mechanisms as non-perseverative substitutions: slowed activation of the intended utterance and linguistic similarity between the target and error. They differ from non-perseverative substitutions in their probability of occurrence, which is increased by residual activation following their recent production. In this article, I will review this account of perseverations and discuss its implications for treatment approaches to reduce perseverations.