The ear craves the familiar: Pragmatic repetition in left and right cerebral damage

Background: Repetition occurs plentifully in normal conversation, but empirical studies of the pragmatic use of repetition are rare and pragmatic repetition, defined as verbal repetition in conversational use, in disordered language has not been systematically investigated. Applying a method of analysis that was piloted utilising normal discourse, discourse samples from persons with left and right brain damaged were examined for incidence and charcteristics of repetition.Aims: The purpose of this exploratory study was to examine verbal repetition following cerebral hemispheric damage. From previous studies of hemispheric influences on communicative competence, it was hypothesised that unilateral damage would affect verbal repetition differently. Following earlier results for hemispheric effects on proportion of formulaic expressions, overall more verbal repetition was predicted in persons with left hemisphere damage than those with right hemisphere damage or healthy speakers. Furthermore, previous studies led to a prediction of more repetition of formulaic (than novel, propositional) expressions following left hemisphere damage than the other two study groups. We explored whether characteristics and functions of repetition, developed as part of a new method for quantifying repetition in spontaneous speech, differed systematically between groups.Methods & Procedures: Transcripts of discourse by persons diagnosed with a single cerebral vascular accident and from age- and education-comparable healthy control (HC) participants were analysed. A method was developed for quantifying verbal repetition and identifying five factors, specifically localness (immediate, delayed, or distant), preservation of the original target (identical or altered), source (self or other), grammatical unit of speech (word, phrase, clause, or sentence), and phrase type (formulaic or novel), and three functions (maintaining form, enhancing content, and socialisation).Outcomes & Results: Results revealed significantly higher use of repetition by left hemisphere (28%) than right hemisphere-damaged (RHD) participants (19%) or the HC group (18%). The proportion of formulaic expression repeated by the left hemisphere group was significantly higher (57%) than the right hemisphere group (30%). Fewer repetitions were used by the left hemisphere group (25%) for the function of enhancing the content of talk as compared to the HC group (40%), whereas the RHD group used the least repetition for socialisation (15%).Conclusions: Pragmatic repetition is to be distinguished from rote repetition (on command) in aphasia diagnosis and from pathological repetition behaviours, including perseveration, following brain damage. The method described here allows for the measurement of pragmatic repetition and its characteristics in normal and disordered language. The findings support previous results for pragmatic and formulaic language behaviours in these populations. This study provides new information on the roles of repetition in normal conversation and on the impact of neurological damage on this function. Identification and measurement of repetition will inform perspectives on evaluation and rehabilitation of conversational speech.