Genre, verb, and coherence in picture-elicited discourse of adults with aphasia

Background: Discourse coherence is derived, in part, from the relationship between and among words and sentences. In studies of aphasia, the relationship between discourse-level and sentence-level phenomena may be examined through the verb. In clinical picture elicitations of discourse, the nature of the pictures or the accompanying elicitation instructions may influence the discourse genre of the response (descriptive vs narrative), which in turn may place different linguistic demands (e.g., verb production demands) on the speaker with aphasia. Aims: This study explores aphasic speakers' partial construction of discourse coherence through relationships between and among action, background, and setting information carried largely by the verb, in picture-elicited discourse productions of two different genres: descriptive and narrative. Methods & Procedures: Twelve individuals with aphasia of mild to moderate severity were presented with five pictures: two composite and three complex. Verbal discourse responses were elicited with common clinical instructions. For the three complex pictures, discourse was also elicited with instructions that explicitly requested temporal sequencing. Discourse genre (descriptive vs narrative) of each response was determined. Verbs within each response were categorised on dimensions of form (tense) and function (degree of association with storyline). Outcomes & Results: For common clinical elicitations, discourse genre was descriptive, verb tense was present and/or non-finite, and verbs filled background and setting functions, regardless of picture type. For elicitations that requested temporal sequencing, participants produced more narrative discourse genre, and more past tense and storyline function on verbs. Exceptions to the group patterns are discussed and exemplified. Conclusions: The patterns of group results and the exceptions to these patterns provide insights into the relationship between the discourse and sentence levels, and the ability of individuals with aphasia to negotiate this relationship in their discourse productions. Findings also hold methodological implications for sampling discourse production among individuals with aphasia.