Impaired recognition of prosody and subtle emotional facial expressions in Parkinson's disease.

Accurately recognizing the emotional states of others is crucial for successful social interactions and social relationships. Individuals with Parkinson's disease (PD) have shown deficits in emotional recognition abilities although findings have been inconsistent. This study examined recognition of emotions from prosody and from facial emotional expressions with three levels of subtlety, in 30 individuals with PD (without dementia) and 30 control participants. The PD group were impaired on the prosody task, with no differential impairments in specific emotions. PD participants were also impaired at recognizing facial expressions of emotion, with a significant association between how well they could recognize emotions in the two modalities, even after controlling for disease severity. When recognizing facial expressions, the PD group had no difficulty identifying prototypical Ekman and Friesen (1976) emotional faces, but were poorer than controls at recognizing the moderate and difficult levels of subtle expressions. They were differentially impaired at recognizing moderately subtle expressions of disgust and sad expressions at the difficult level. Notably, however, they were impaired at recognizing happy expressions at both levels of subtlety. Furthermore how well PD participants identified happy expressions conveyed by either face or voice was strongly related to accuracy in the other modality. This suggests dysfunction of overlapping components of the circuitry processing happy expressions in PD. This study demonstrates the usefulness of including subtle expressions of emotion, likely to be encountered in everyday life, when assessing recognition of facial expressions.