Part of the message comes in gesture: how people with aphasia convey information in different gesture types as compared with information in their speech

Background: Studies have shown that the gestures produced by people with aphasia (PWA) can convey information useful for their communication. However, the exact significance of the contribution to message communication via gesture remains unclear. Furthermore, it remains unclear how different gesture types and representation techniques impact message conveyance.Aims: The present study aimed to investigate the contribution of gesture to PWA's communication. We specifically focussed on the degree to which different gesture types and representation techniques convey information absent in the speech of PWA.Methods & Procedure: We studied the gestures produced by 46 PWA and nine non-brain-damaged participants (NBDP) during semi-structured conversation. For each of the different types of gestures and representation techniques we identified whether these conveyed essential information, that is information that was absent in speech. Rather than looking at information that was either similar to information in speech or additional to information in speech, we focused on the essential gestures only.Outcomes & Results: For PWA, a fifth of their gestures were Essential. Despite individual differences between PWA, the majority produced more Essential gestures than NBDP, who produced limited amounts of Essential gestures. Essential information was mostly conveyed by specific gesture types: Pointing, Emblems and Iconic gesture. Within the group of iconic gestures, not only Handling and Enact but also Object and Shape gestures, were often Essential.Conclusions: Our findings suggest that a great proportion of gestures produced by most PWA convey information essential for understanding their communication. In their communication advice, speech language therapists could draw attention to specific gesture types to make sure that interlocutors pay more attention to these gestures when communicating with PWA.