Facial expression recognition in mild cognitive impairment and dementia: is the preservation of happiness recognition hypothesis true?

Aim: Social cognition encompasses facial expression recognition (FER), theory of mind, and empathy. Although studies examining FER in large numbers of patients with mild cognitive impairment (MCI) or dementia are rare, relative preservation of happiness recognition in dementia was reported in some studies. In this study, we examined performance on FER tests and its relationship to clinical demographics and other cognitive function test scores in patients with cognitive decline. Methods: The present study administered an FER test and several cognitive tests to outpatients at a memory clinic. The FER test presents four facial expressions (happiness, surprise, anger, and sadness). A total of 187 patients were placed in one of the three groups based on their cognitive status: dementia group (n = 63), MCI group (n = 92), and normal cognition group (n = 32). Results: The total scores on the FER test significantly differed among the three groups (normal > MCI > dementia). In the recognition of happiness and surprise, the dementia group had significantly lower scores than the normal cognition group. There were no significant differences in the recognition of anger and sadness scores among the three groups. The FER scores for happiness and surprise were primarily related to executive function scores, but the FER scores for anger and sadness were primarily related to age. Conclusions: We note the difference in recognition of causative factors among the four emotions (happiness, surprise, anger, sadness). Our study raises serious doubts about the preservation of happiness recognition hypothesis in dementia based on FER tests.