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

Social cognition is impaired in people with dementia but the differences in social cognitive impairment between mild cognitive impairment (MCI) and dementia and its subtypes remain unclear. We therefore aimed to systematically review and meta-analyze differences in emotion recognition, theory of mind (ToM), and empathy between individuals with MCI and dementia. Across 28 cross-sectional studies (n = 2409), people with MCI had better emotion recognition (Cohen's d = 0.69) and ToM (d = 0.70) than individuals with Alzheimer's disease (AD) dementia, and larger effect sizes were observed for people with frontotemporal dementia (FTD) (emotion recognition (d = 2.09), ToM (d = 1.49), but emotional empathy was higher in AD than in MCI in included studies. Our findings suggest a progressive decline of aspects of social cognition across the MCI-dementia continuum. Longitudinal studies should investigate the diagnostic role of social cognition deficits in MCI progression to dementia, and interventions for social cognition in MCI should be developed and tested. HIGHLIGHTS: First systematic review and meta-analysis comparing social cognition between mild cognitive impairment (MCI) and dementia subtypes. Findings from 28 studies with 2409 participants show people with MCI outperform those with Alzheimer's disease (AD) and frontotemporal dementia (FTD) in emotion recognition and theory of mind. Empathy appears intact in AD dementia, suggesting that this cognitive domain is preserved throughout disease progression. Evaluation of social cognition should be built into dementia assessment as it may hold diagnostic value.