Glottal Source Analysis of Voice Deficits in Newly Diagnosed Drug-naïve Patients with Parkinson’s Disease: Correlation Between Acoustic Speech Characteristics and Non-Speech Motor Performance

Abstract

As dysphonia is assumed to be the most prevalent feature of hypokinetic dysarthria in Parkinson’s disease (PD), several acoustic approaches have been introduced for its assessment. However, the sensitivity of different acoustic measures to the occurrence of dysphonia in drug-naïve de-novo patients with PD has not yet been explored. The goal of this study is to examine the performance of glottal source parametrization and compare it with traditional perturbation and cepstral measures. Sustained phonations of 40 de-novo drug-naïve PD participants and 40 age- and sex-matched healthy controls were recorded. Each utterance was ranked by a set of glottal source parameters obtained by inverse adaptive filtering, the perturbation parameters, and cepstral peak prominence measures. Our results revealed the significant differences in the glottal source parameter Harmonic Richness Factor (HRF: p < 0.01) and cepstral peak prominence parameter (p < 0.05). The support vector machine classification between PD and healthy controls reached the area under the curve of 0.78. The analysis of relationships showed significant negative correlations between HRF and total Movement Disorders Society – Unified Parkinson’s Disease Rating Scale III score (r=-0.35, p < 0.05), as well as its rigidity (r=-0.43, p < 0.01) and bradykinesia (r=-0.32, p < 0.05) sub-scores. Glottal source assessment appears to be a superior method to assess PD-related dysphonia compared to the traditional perturbation and cepstral approaches. Our results highlight that dysphonia and limb bradykinesia and rigidity in PD are controlled by similar underlying brain processes.