The influence of conversation parameters on gesture production in aphasia.

Conversation is important in everyday life and this importance is not diminished in aphasia. Context parameters such as topic and partner are known to influence the linguistic content of conversations. With gesture being closely linked to language, these parameters may influence gestures used in conversations. This has not been investigated in previous studies. This study explored the spontaneous use of gestures in the conversations of participants with aphasia (PWA) and neurologically healthy participants (NHP). It aimed to examine the influence of conversation topic and partner on gesture production overall and on the production of semantically rich and empty gestures. Twenty PWA and 21 NHP were filmed during conversations with different topics (narrative & procedural) and different partners (familiar & unfamiliar). Analysis 1 investigated the influence of the conversation topic on gesture production overall and on the production of semantically rich and empty gestures. In Analysis 2, the influence of the conversation partner on gesture production was investigated. Both groups produced significantly more gestures in procedural than in narrative conversations. Moreover, PWA and NHP produced significantly more semantically rich gestures in procedural conversations. In terms of the conversation partner, both groups produced significantly more gestures in the conversations with the unfamiliar than in those with the familiar conversation partner. For all findings, there were no group differences and no interactions between group and context parameters. These findings shed light on factors that influence gesture production and suggest that both modalities should be viewed together as a communicative resource for PWA.

TOT phenomena: Gesture production in younger and older adults.

This study explored age-related changes in gesture to better understand the relationship between gesture and word retrieval from memory. The frequency of gestures during tip-of-the-tongue (TOT) states highlights this relationship. There is a lack of evidence describing the form and content of iconic gestures arising spontaneously in such TOT states and a parallel gap addressing age-related variations. In this study, TOT states were induced in 45 participants from 2 age groups (older and younger adults) using a pseudoword paradigm. The type and frequency of gestures produced was recorded during 2 experimental conditions (single-word retrieval and narrative task). We found that both groups experienced a high number of TOT states, during which they gestured. Iconic co-TOT gestures were more common than noniconic gestures. Although there was no age effect on the type of gestures produced, there was a significant, task-specific age difference in the amount of gesturing. That is, younger adults gestured more in the narrative task, whereas older adults generated more gestures in the single-word-retrieval task. Task-specific age differences suggest that there are age-related differences in terms of the cognitive operations involved in TOT gesture production.