Factors Associated with the Social Behaviour of People with Alzheimer’s Dementia: A Video Observation Study

<b>Background/Objectives:</b> People with Alzheimer's dementia (AD) experience distressing changes in social behaviour. However, little is understood about whether social behaviour is associated with support provided by, or familiarity with, conversation partners. We aimed to explore the association between support provided by, and familiarity with, conversation partners and the social behaviour of people with mild AD during conversation. <b>Method:</b> We designed an exploratory within-subjects study wherein conversations between 19 participants with mild AD and a familiar informant, followed by an unfamiliar researcher, were video-recorded and double-rated using two measures of social behaviour (Social Observation Inventory and Measure of Participation in Conversation-Dementia), and one measure of support from the conversation partner (Measure of Support in Conversation-Dementia). Multilevel linear regression with within-subject clusters was used to explore adjusted associations between support and familiarity and social behaviour. <b>Results:</b> Greater support in conversation was associated with more appropriate participation in social conversation of participants with AD. In fully adjusted models, every 1-point increase in MSC-D score was associated with a 0.29 (95% CI: 0.14 to 0.44) increase in MPC-D score and a 1.59 (95% CI: 0.87 to 2.32) increase in SOI score. Familiarity with the conversation partner was not associated with the social behaviour of the participants with AD. <b>Conclusions:</b> We found evidence for an association between social behaviour in AD and support provided by unimpaired conversation partners, but the numbers were small, and this should be interpreted cautiously. Future research should continue this hypothetical lead to expand our understanding of how support and familiarity influence social behaviour to inform potential interventions.