Relationship between acoustic measures and speech naturalness ratings in Parkinson’s disease: A within-speaker approach

Abstract

This study investigated the acoustic basis of across-utterance, within-speaker variation in speech naturalness for four speakers with dysarthria secondary to Parkinson's disease (PD). Speakers read sentences and produced spontaneous speech. Acoustic measures of fundamental frequency, phrase-final syllable lengthening, intensity and speech rate were obtained. A group of listeners judged speech naturalness using a nine-point Likert scale. Relationships between judgements of speech naturalness and acoustic measures were determined for individual speakers with PD. Relationships among acoustic measures also were quantified. Despite variability between speakers, measures of mean F0, intensity range, articulation rate, average syllable duration, duration of final syllables, vocalic nucleus length of final unstressed syllables and pitch accent of final syllables emerged as possible acoustic variables contributing to within-speaker variations in speech naturalness. Results suggest that acoustic measures correlate with speech naturalness, but in dysarthric speech they depend on the speaker due to the within-speaker variation in speech impairment.

Abstracts of the 8th International Conference on Speech Motor Control Groningen, August 2022

“…Symptoms of the speech disorder may for instance limit a speaker´s intelligibility and naturalness as perceived by communication partners. In adults with dysarthria, intelligibility and naturalness have been shown to be closely connected and determined by symptoms related to different speech subsystems (Klopfenstein, 2015;Legner & Ziegler, 2022;Schölderle et al, 2016). In children with dysarthria, communication-related research has predominantly focused on intelligibility, while naturalness has not been studied comprehensively so far, neither on its own, nor in its relationship to intelligibility.…”

The relationship of rate and pause features to the communicative participation of people living with ALS

“…53,54 Even among healthy speakers, those with a faster speaking rate may be judged as more competent and socially attractive than speakers with a slower rate. 55 Alternatively, rate and pause features may indirectly interfere with communicative participation by indexing a third variable, 56,57 such as speech impairment severity. Future studies on the effects of rate modification are needed to further investigate its direct and indirect impacts on communicative participation.…”

Perceived Naturalness of Electrolaryngeal Speech Produced Using sEMG-Controlled vs. Manual Pitch Modulation

“…It is also likely that factors other than pitch variability contribute to naturalness, even for EL speech. Rate, rhythm, stress pattern and volume are just a few of these known factors [14,15]. Although amplitude was equalized for all samples in this study, we did not control speech rate, rhythm or stress patterns when eliciting stimuli.…”

“…Pitch variation, as measured by standard deviation of f0, was significantly higher when using the EMG-EL than TruTone EL, for all Speakers (p<.001). (14) 90 3Speaker 1, whose naturalness ratings were consistently low, expressed a preference for higher pitch and produced a notably higher f0 from other Speakers throughout the testing.…”