Social cognition in mild cognitive impairment and dementia: a systematic review and meta-analysis

IntroductionSocial cognition is known to be impaired in people with dementia but the differences in social cognitive impairment between MCI and dementia and its subtypes remain unclear. We aimed to systematically review and meta-analyse differences in emotion recognition, theory of mind (ToM) and empathy, between individuals with MCI and those with dementia.MethodsWe searched databases for studies comparing social cognition between people with MCI and dementia groups and conducted meta-analyses for differences in emotion recognition, ToM, and empathy.ResultsFrom 2,490 identified studies, 28 cross-sectional studies involving 2,368 participants (1,273 MCI, 1,145 dementia) met inclusion criteria. People with MCI had better emotion recognition (Cohen’s d = 0.69) and ToM (Cohen’s d = 0.74) than those with Alzheimer’s disease (AD) dementia and larger effect sizes were observed for people with frontotemporal dementia (FTD) (emotion recognition (Cohen’s d = 2.09) and ToM (Cohen’s d = 1.49)). People with AD showed slightly higher emotional empathy compared to MCI in the included studies. DiscussionOur findings suggest progressive decline of aspects of social cognition across MCI-dementia continuum, with potential for early detection and intervention. Longitudinal studies are needed to investigate the predictive role of social cognition deficits in progression from MCI to dementia and interventions for social cognition in MCI should be developed and tested.