“Like déjà vu all over again”: Patterns of perseveration in two people with jargon aphasia

Abstract

Background: It has been argued that perseveration type corresponds to the level of breakdown, so that total perseveration (repetition of a whole word) involves reactivation of a previous word at the lexical level when the target word is insufficiently activated. A blended perseveration (repetition of part of a previous response) results from a failure of target activation at the phoneme level (e.g., Martin & Dell, 2007). This is challenged by the occurrence of nonword total perseverations, as these cannot be lexical retrievals (Hirsh, 1998). A further problem is the occurrence of long intervals between perseverations and their sources. Some authors have invoked semantic relationships to explain these intervals (e.g., Martin, Roach, Brecher, & Lowery, 1998). Aims: This study examines the perseveration of two individuals with jargon aphasia and explores the proposal that while some perseveration may result from reactivation of recent responses as described above, others are built around default phonology, resulting in stereotypical errors. Methods & Procedures: Tests of naming, reading, and repetition were administered. Responses were analysed to determine: the extent of perseveration; the occurrence of long intervals between perseverations and their sources; patterns of phoneme use; the occurrence of nonword total perseverations. Outcomes & Results: Both individuals produced large numbers of perseverative responses. Perseverative responses following lengthy intervals could not be explained by semantic relationships. For each participant certain consonants were favoured and evidence was found of an interaction between the occurrence of perseveration and these favoured consonants. The possibility that word and nonword total perseverations arose from different sources was rejected because no difference was found in the use of the favoured phonemes in the two types. Conclusions: The findings support the theory of two mechanisms for perseveration. The first is local, occurring when residual activation overrides incoming activation. This is confined to a single utterance and appears closely after the original occurrence. The second type is global, occurring across different contexts over time. It originates from default phonology when incoming activation is unavailable at the phoneme level. Both total and blended perseverations may result from this mechanism. Word total perseverations may be favoured because of feedback from the phoneme level to the lexical level. Ideas for future research and implications for intervention are discussed.