Task-specific iconic gesturing during spoken discourse in aphasia
Purpose: Identify main effect of task, as well as roles of spoken language and demographic details, on iconic gesture production during spontaneous speech in persons living with aphasia.Method: Employing the AphasiaBank database, we coded iconic gestures in N=75 speakers with aphasia during two spoken discourse tasks: a procedural narrative, which involved participants telling the experimenter how to make a sandwich (“Sandwich”), and a picture sequence narrative, which had participants describe the picture sequence to the experimenter (“Window”). N=43 produced a gesture during both tasks, and this subgroup serves as a more direct comparison between tasks.Results: More iconic gestures, at a higher rate, were produced during the procedural narrative. For both tasks, there was a relationship between iconic gesture rate, modeled as iconic gestures per word, and metrics of language dysfluency extracted from the discourse task, and a metric of fluency extracted from a standardized battery. Iconic gesture production was correlated with aphasia duration, which was driven by performance during only a single task (Window), but not with other demographic metrics, such as aphasia severity or age. Conclusions: Whilst speech-language pathologists have utilized gesture in therapy for post-stroke aphasia, due to its possible facilitatory role in spoken language, there has been considerably less work in understanding how gesture differs across naturalistic tasks, and how we can best utilize this information to better assess and treat gesture in aphasia. Further, our results contribute to gesture theory, in particular about the role of gesture across naturalistic tasks, and its relationship with spoken language.