Facial Expression Processing Is Not Affected by Parkinson's Disease, but by Age-Related Factors.

The question whether facial expression processing may be impaired in Parkinson's disease (PD) patients so far has yielded equivocal results - existing studies, however, have focused on testing expression processing in recognition tasks with static images of six standard, emotional facial expressions. Given that non-verbal communication contains both emotional and non-emotional, conversational expressions and that input to the brain is usually dynamic, here we address the question of potential facial expression processing differences in a novel format: we test a range of conversational and emotional, dynamic facial expressions in three groups - PD patients ( = 20), age- and education-matched older healthy controls ( = 20), and younger adult healthy controls ( = 20). This setup allows us to address both effects of PD and age-related differences.