Parkinson’s Disease (PD) is a neurodegenerative disorder which can substantially affect nonmotor functions related to emotional processing. However, previous studies investigating the effects of PD on emotional processing have produced conflicting results. In the current study, we aimed to examine the underlying differences in emotional processing in PD by comparing how early-stage PD patients rate and react to emotional stimuli in three modalities on an Emotion Survey. Data analysis focused on identifying differences in emotion recognition, bias, and emotional range together with clinical outcome measures. Our results showed that PD patients were more accurate than healthy controls at identifying correct emotions. Furthermore, when clinical scores were correlated with ratings of emotional stimuli, PD patients alone showed a general increase in ratings and reactions to both positive and negative stimuli, thereby yielding significant correlations between clinical outcomes and emotional range in the PD patient group. Our results suggest that alterations in emotional regulation may underlie changes in emotional processing in early PD.
The basal ganglia circuits, dopamine, and ambiguous word processing: A neurobiological account of priming studies in Parkinson's disease