Effects of aging on speech perception of individuals with and without Parkinson disease

Abstract

Purpose A majority of individuals with Parkinson disease (PD) experience speech changes over time. Due to limited understanding of factors utilized by untrained listeners to identify Parkinsonian speech at discourse level, the present study examined aging effects on perception of Parkinsonian speech by three different listener groups (younger, middle-aged, and older-aged adults). Methods The study included five speakers with PD and five age-and-gender matched healthy control speakers. A total of 60 listeners (younger adults, middle-aged adults, and older adults) completed perceptual ratings based on six speech variables (including pitch, pitch variability, loudness, speech rate, pauses, and understandability). In addition, all listeners predicted whether or not the speaker they had listened to had PD. Results Older-aged listeners demonstrated significantly less than ideal ratings for loudness and understandability compared to younger and middle-aged groups. The prediction of whether or not a speaker had PD was dependent on different speech dimensions. In addition, all listener groups correctly identified the speaker with the most advanced disease severity. Conclusions Older-aged listeners demonstrated changes in speech perception of individuals with and without PD during quiet listening conditions. In addition, all listener groups were perceptive of voice changes secondary to PD during the perceptual rating task. Listener groups demonstrated different trends with younger adults more likely to attribute any changes in speech to a disorder while older-aged adults more likely to accept the changes in speech as normal aging effects. Overall, the study provided evidence for potential listener-assisted or listener-based rehabilitation techniques for individuals with PD. Keywords: Perceptual speech ratings; Parkinson disease; Speakers with PD; Aging effects; Listener groups; Prediction of Parkinson disease