Perception of emotions in mild cognitive impairment and Alzheimer’s dementia: does intensity matter?

BACKGROUND To provide a review of the literature on the perception of emotion in Alzheimer's dementia (AD) and Mild cognitive impairment (MCI), and to evaluate if emotion intensity matters. METHODOLOGY A systematic literature search of PubMed database was carried out using combinations or truncated versions of the keywords "MCI", "Alzheimer", "emotion recognition", "facial emotion recognition", "social cognition" or "emotion perception". Twenty-eight articles were found to meet the inclusion criteria. RESULTS Overall, AD patients performed worse on emotion perception than MCI patients and healthy controls. Half of the studies found an emotion-specific deficit for MCI patients on the emotions anger, sadness and fear. However, studies taking emotion intensity into account are still scarce. CONCLUSIONS An emotion-intensity based approach may be more sensitive to detect subtle impairments in facial emotion recognition. Future studies need to take emotion intensity into account and also consider confounding factors such as overall cognition and mood.