Listener impressions of speakers with Parkinson's disease.

Parkinson's disease (PD) has several negative effects on speech production and communication. However, few studies have looked at how speech patterns in PD contribute to linguistic and social impressions formed about PD patients from the perspective of listeners. In this study, discourse recordings elicited from nondemented PD speakers (n = 18) and healthy controls (n = 17) were presented to 30 listeners unaware of the speakers' disease status. In separate conditions, listeners rated the discourse samples based on their impressions of the speaker or of the linguistic content. Acoustic measures of the speech samples were analyzed for comparison with listeners' perceptual ratings. Results showed that although listeners rated the content of Parkinsonian discourse as linguistically appropriate (e.g., coherent, well-organized, easy to follow), the PD speakers were perceived as significantly less interested, less involved, less happy, and less friendly than healthy speakers. Negative social impressions demonstrated a relationship to changes in vocal intensity (loudness) and temporal characteristics (dysfluencies) of Parkinsonian speech. Our findings emphasize important psychosocial ramifications of PD that are likely to limit opportunities for communication and social interaction for those affected, because of the negative impressions drawn by listeners based on their speaking voice.