Comparing Acoustic Parameters of Conversational and Clear Speech during Reading in Kannada Speaking Individuals with Parkinson's Disease

Abstract

The current study compared acoustic parameters of reading samples produced in clear speech and conversational speech conditions by individuals with Parkinson's disease (PD), grouped into three groups of PD (early, middle and late PD) depending on disease progression. A listener judgement task validated that instructions given to persons with PD to speak clearly indeed resulted in differences in speech production with a large proportion of listener's judgments indicating a preference for clear speech condition in comparison to conversational speech condition. Acoustic analysis of reading passages demonstrated significantly increased standard deviation of Fo, standard deviation of intensity as well as greater duration (reduced articulatory rate) in the clear speech condition in comparison to conversational reading. Further differences among the three groups of participants with PD in acoustic parameters reveal trade-off's in the acoustic measures possibly reflecting differences in physiological capacities with the progression of the disease.