Social Cognition and Social Functioning in MCI and Dementia in an Epidemiological Sample

Abstract Objective: Social cognition is impaired in mild cognitive impairment (MCI) and dementia. However, its relationship to social functioning and perceived social support has yet to be explored. Here, we examine how theory of mind (ToM) relates to social functioning in MCI and dementia. Methods: Older adults (cognitively normal = 1272; MCI = 132; dementia = 23) from the PATH Through Life project, a longitudinal, population-based study, were assessed on the Reading the Mind in the Eyes Test (RMET), measures of social functioning, and social well-being. The associations between RMET performance, social functioning, and cognitive status were analysed using generalised linear models, adjusting for demographic variables. Results: Participants with MCI ( b =−.52, 95% CI [−.70, −.33]) and dementia ( b =−.78, 95% CI [−1.22, −.34]) showed poorer RMET performance than cognitively normal participants. Participants with MCI and dementia reported reduced social network size ( b =−.21, 95% CI [−.40, −.02] and b =−.90, 95% CI [−1.38, −.42], respectively) and participants with dementia reported increased loneliness ( b = .36, 95% CI [.06, .67]). In dementia, poorer RMET performance was associated with increased loneliness ( b =−.07, 95% CI [−.14, −.00]) and a trend for negative interactions with partners ( b =−.37, 95% CI [−.74, .00]), but no significant associations were found in MCI. Conclusions: MCI and dementia were associated with poor self-reported social function. ToM deficits were related to poor social function in dementia but not MCI. Findings highlight the importance of interventions to address social cognitive deficits in persons with dementia and education of support networks to facilitate positive interactions and social well-being.