Acoustical and Perceptual Analysis of Voice in Individuals with Parkinson's Disease

Parkinson's disease is a neurodegenerative disorder that affects motor efficiency which is also required for voice production. Voice is part of the identity of a person, any abnormality in voice quality hampers the quality of communication, and quality of life. This study aimed to analyse the voice of individuals with Parkinson's disease objectively through acoustic analysis, and subjectively through perceptual analysis. Quasi-experimental study conducted in a tertiary health care centre. The study comprised two groups: 12 individuals with Parkinson's disease (11 males and 1 female, mean age: 72.41 years), and 12 healthy controls (10 males and 2 females, mean age: 53.83 years). The voice samples of all the participants were recorded and analyzed using the MDVP software of CSL 4500. The voice samples were analyzed for eleven acoustical parameters, and the perceptual analysis was carried out using the GRBAS scale by two experienced Speech Language Pathologists. Mann-Whitney U test was performed to compare the two groups of participants, and Cronbach's alpha test was performed to find the inter-judge reliability between the perceptual ratings of two listeners. Acoustical comparison showed significant variations in seven parameters (jitter, shimmer, PPQ, APQ, Fatr Hz, Fftr, ATRI), and the perceptual analysis between two listeners showed a fair amount of reliability.