Psycholinguistic variables influencing conduite d’approche in repetition tasks: an experimental exploration and mediation analysis in a person with conduction aphasia

Background Following brain damage, some individuals exhibit a form of self-corrective verbal behaviour in which they repeatedly attempt to refine their speech in order to retrieve a target word. This behaviour, traditionally termed conduite d’approche (CdA), provides a window onto the mechanisms used by the cognitive and neural systems to correct errors during language production.Aims In this study, we investigated the levels of language processing that give rise to and shape the production of CdA in ANC, a person with reproduction conduction aphasia, by examining the impact on this behaviour of various psycholinguistic variables associated with both phonological dorsal areas and lexico-semantic ventral areas.Methods We first explored the factors influencing the production of correct responses, CdA, and the number of attempts in a series of controlled experiments involving word and pseudoword repetition tasks. Next, we conducted a further analysis of the variables involved in the production of CdA and the number of attempts, as well as the mediating role of these two indices in final word access, through Bayesian mediation analyses on a more comprehensive word repetition dataset, combining data from these experiments with additional assessments.Results Our findings revealed a significant role of word length, with longer words leading to more erroneous responses, more instances of CdA, and a greater number of attempts. Syllable and word frequency effects, however, were not consistent. The more statistically powerful mediation analyses further confirmed the relevance of word length and additionally identified a role of imageability, which influenced both the number of attempts and the likelihood of successful word access, an effect that was not observed in the experimental tasks alone.Conclusions These findings align with the notion that when dorsal regions involved in phonological processing are lesioned in conduction aphasia, the affected individuals compensate for difficulties in their production by relying on lexico-semantic processes subserved by spared ventral structures to produce successful CdAs and hence the desired word.