Facial emotion recognition in neurological disorders: a narrative review.

Facial emotion recognition refers to a person's interpretation of facial features of another to identify a particular emotional state. It is essential in human evolution and encompasses distinct neural networks. Facial emotion recognition is altered in most neurodegenerative diseases, but literature just focus on single neurological pathologies or limited comparison with psychiatric pathologies. It is unknown if a common pattern of affection through pathologies exists or if facial emotion recognition changes according to the underlying pathology. This review discusses its development in healthy population, synthesizes facial emotion recognition studies regarding most common neurological diseases, as well as most relevant findings in neuroimaging and current treatments. Facial emotion recognition, especially negative emotions, is altered in all described neurodegenerative diseases and could constitutes an early marker of cognitive deterioration.