Vocal Emotional Expression in Parkinson's Disease: Roles of Sex and Emotions

Introduction: Parkinson's disease (PD) commonly causes speech impairments, including difficulties in expressing emotions through voice. Method: The objective of this study was to investigate gendered vocal expressions of fear, anger, sadness, and happiness for mild to moderate PD. Prosodic features (related to fundamental frequency (F0), intensity (I), speech rate, articulation rate, and number and duration of pauses) and acoustic correlates of voice quality (CPPS, jitter, shimmer, and HNR) were collected from 14 patients with PD (mean age = 69.93; SD = 7.12; 8 males, 6 females) and 13 healthy controls (HC) (mean age = 68.13; SD = 8.27; 5 males, 8 females) matched for age, sex, and years of education. The utterances were extracted from four emotional and one neutral text. The neutral utterance and the emotional utterances were compared. Intra-sex comparison (female with PD vs. female HC and male with PD vs. male HC) and inter-sex comparison (female vs. male both for patients with PD and for HC), were performed with the Mann-Whitney test. A Mann-Whitney test was also used to compare the different emotional conditions, considering sex and PD diagnosis as well. Results: No significant intra-sex differences were found for the neutral speech, but inter-sex differences emerged. Regarding emotional speech, females with PD featured lower MaxF0 than female HCs for happiness and higher intensity variability (SD I) for sadness. Utterances by females with PD had lower CPPS than utterances by HCs for anger and fear. Utterances by males with PD had lower minimum intensity (MinI) than utterances by male HCs when expressing fear. Conclusions: Emotional vocal expression in individuals with PD was found to be impaired and showed sex differences. These findings have the potential to significantly impact the quality of life of PD patients.