Abstract
We have designed a quick vocal test consisting of sustained phonation, diadochokinetic task, and running speech, and assessed its performance in separating PD patients from healthy controls (HC). 24 untreated patients with recently diagnosed PD and 22 age-matched HC were tested. Using a kernel support vector machine, the best classification performance of 85.02% was reached in a combination of four measures that represent all PD-related speech subsystems, including the ability to maintain sound pressure level, noise-to-harmonics ratio, accuracy of articulation, and melody variations.
Reduced melody in running speech appeared essential in characterizing the vocal impairment in PD. In addition, correlations were found between the measures of articulation and phonation, and subscores of bradykinesia and rigidity.
Our designed configuration of acoustic vocal tests can detect abnormalities of speech since the early untreated stages of PD.