Considering a multi-level approach to understanding maintenance of global coherence in adults with aphasia

Background: Discourse is a naturally occurring, dynamic form of communication. Coherence is one aspect of discourse and is a reflection of the listener's ability to interpret the overall meaning conveyed by the speaker. Adults with aphasia may present with impaired maintenance of global coherence, which in turn may contribute to their difficulties in overall communicative competence. Aims: The aim of the study was to determine if microlinguistic processes contribute to maintenance of global coherence in adults with and without aphasia. Method & Procedures: Participants included 15 adults with aphasia (PWA) and 15 healthy controls (HC). Study participants told stories conveyed in wordless picture books. The discourse samples were transcribed and then analysed for percent of information units produced, lexical diversity, syntactic complexity, and maintenance of global coherence. Outcomes & Results: Several linear regression models were carried out to investigate the relationship among the microlinguistic and macrolinguistic measures. For the control group, percent of information units conveyed was a significant predictor of maintenance of global coherence for stories told. For the aphasia group, percent of information units conveyed and lexical diversity were significant predictors of maintenance of global coherence for stories told. Conclusions: Results indicated that microlinguistic processes contribute to the maintenance of global coherence in stories told by adults with aphasia. These findings have important clinical implications for using a multi-level discourse model for analysing discourse ability in adults with aphasia and measuring individual response to treatment.