Acoustic Correlates of Timing Typicality in Speakers With Parkinson's Disease

The present study aimed to determine acoustic metrics that can approximate listener perception of the typicality of speech timing in individuals with Parkinson's disease (PD). It was hypothesized that the perception of timing typicality would correlate with measures based on the deviation from speech produced by individuals with typical speech (in speaking duration, in pause time and other disfluencies, and at the word level).

Twenty speakers with PD and 40 typical speakers matched in age and sex were recorded reading a standard passage. Acoustic timing measures were calculated for the speakers with PD, both absolute and relative to recordings from the typical speakers. Linear regression models were used to estimate the relationship strength between each acoustic measure and the perception of timing typicality. Models containing all variables and subsets of variables were compared to test study hypotheses.

A model consisting of mean word duration and mean interword duration, both in their absolute values and relative to control speakers, explained substantial variance in perceptual judgments of timing typicality in speakers with PD (R² = .93).

Timing measures based on the deviation from normative values and accounting for pausing and disfluencies may provide an acoustic basis for estimating timing typicality in people with PD. Future work should examine these acoustic metrics in a larger sample to determine their utility in research and clinical settings.