Quantitative acoustic measurements for characterization of speech and voice disorders in early untreated Parkinson’s disease

TLDR

The study aimed to detect early voice and speech disorders in untreated Parkinson’s disease, characterize their acoustic signatures, and develop new automatic articulation measurement methods. Researchers collected speech recordings from 46 Czech speakers (23 with PD), pre‑selected 19 acoustic measures, and used Wald sequential analysis to evaluate each measure’s discriminative power and the degree of vocal impairment. Fundamental frequency variation on two tasks best distinguished healthy from PD subjects; 78 % of early untreated PD patients exhibited vocal impairment, with individual differences in phonation, articulation, and prosody.

Abstract

An assessment of vocal impairment is presented for separating healthy people from persons with early untreated Parkinson’s disease (PD). This study’s main purpose was to (a) determine whether voice and speech disorder are present from early stages of PD before starting dopaminergic pharmacotherapy, (b) ascertain the specific characteristics of the PD-related vocal impairment, (c) identify PD-related acoustic signatures for the major part of traditional clinically used measurement methods with respect to their automatic assessment, and (d) design new automatic measurement methods of articulation. The varied speech data were collected from 46 Czech native speakers, 23 with PD. Subsequently, 19 representative measurements were pre-selected, and Wald sequential analysis was then applied to assess the efficiency of each measure and the extent of vocal impairment of each subject. It was found that measurement of the fundamental frequency variations applied to two selected tasks was the best method for separating healthy from PD subjects. On the basis of objective acoustic measures, statistical decision-making theory, and validation from practicing speech therapists, it has been demonstrated that 78% of early untreated PD subjects indicate some form of vocal impairment. The speech defects thus uncovered differ individually in various characteristics including phonation, articulation, and prosody.