Objectives: Parkinson's disease (PD) is associated with deficits in social cognition and visual perception, but little is known about how the disease affects perception of socially complex biological motion, specifically motion-defined communicative and non-communicative gestures. We predicted that individuals with PD would perform more poorly than normal control (NC) participants in discriminating between communicative and non-communicative gestures, and in describing communicative gestures. We related the results to the participants' gender, as there are gender differences in social cognition in PD.
Methods: The study included 23 individuals with PD (10 men) and 24 NC participants (10 men) matched for age and education level. Participants viewed point-light human figures that conveyed communicative and non-communicative gestures and were asked to describe each gesture while discriminating between the two gesture types.
Results: PD as a group were less accurate than NC in describing non-communicative but not communicative gestures. Men with PD were impaired in describing and discriminating between communicative as well as non-communicative gestures.
Conclusions: The present study demonstrated PD-related impairments in perceiving and inferring the meaning of biological motion gestures. Men with PD may have particular difficulty in understanding the communicative gestures of others in interpersonal exchanges.
Keywords: Biological motion; Gender; Interpersonal relations; Motor activity; Neurodegenerative diseases; Social behavior.