An Acoustic Study of the Relationships Among Neurologic Disease, Dysarthria Type, and Severity of Dysarthria

TLDR

The study investigated acoustic predictors of speech intelligibility in dysarthric speakers across disease, severity, and dysarthria type, using classification analysis based solely on acoustic measures. Speech recordings from 107 dysarthric speakers (Parkinson’s disease, stroke, traumatic brain injury, multiple system atrophy) were acoustically analyzed using eight segmental/suprasegmental features (2nd formant slope, articulation rate, voiceless interval duration, fricative moment analysis, vowel space, F0, intensity range, and Pairwise Variability Index) and perceptual intelligibility judgments. Acoustic predictors of intelligibility varied slightly across diseases, and classification accuracy was lower for dysarthria type than for disease type or severity.

Abstract

Purpose This study examined acoustic predictors of speech intelligibility in speakers with several types of dysarthria secondary to different diseases and conducted classification analysis solely by acoustic measures according to 3 variables (disease, speech severity, and dysarthria type). Method Speech recordings from 107 speakers with dysarthria due to Parkinson’s disease, stroke, traumatic brain injury, and multiple system atrophy were used for acoustic analysis and for perceptual judgment of speech intelligibility. Acoustic analysis included 8 segmental/suprasegmental features: 2nd formant frequency slope, articulation rate, voiceless interval duration, 1st moment analysis for fricatives, vowel space, F0, intensity range, and Pairwise Variability Index. Results The results showed that (a) acoustic predictors of speech intelligibility differed slightly across diseases and (b) classification accuracy by dysarthria type was typically worse than by disease type or severity. Conclusions These findings were discussed with respect to (a) the relationship between acoustic characteristics and speech intelligibility and (b) dysarthria classification.