Assessing progress of Parkinson's disease using acoustic analysis of phonation

Abstract

This paper deals with a complex acoustic analysis of phonation in patients with Parkinson's disease (PD) with a special focus on estimation of disease progress that is described by 7 different clinical scales (e. g. Unified Parkinson's disease rating scale or Beck depression inventory). The analysis is based on parametrization of 5 Czech vowels pronounced by 84 PD patients. Using classification and regression trees we estimated all clinical scores with maximal error lower or equal to 13 %. Best estimation was observed in the case of Mini-mental state examination (MAE = 0.77, estimation error 5.50 %). Finally, we proposed a binary classification based on random forests that is able to identify Parkinson's disease with sensitivity SEN = 92.86 % (SPE = 85.71 %). The parametrization process was based on extraction of 107 speech features quantifying different clinical signs of hypokinetic dysarthria present in PD.

Changes in Phonation and Their Relations with Progress of Parkinson’s Disease

“…In our view, using only a sustained phonation of the vowel /a/ is not fully justified as there is very little or no reason to assume that this particular position of the tongue can provide more information about phonatory disorders. In fact, as shown by previous studies, the analysis of other vowels is important for a more robust description of HD [19][20][21]23,24,[35][36][37].…”

“…On the other hand, the lowest limit position of jaw is reached during the phonation of vowel /a/. In summary, although some research teams employed a more complex set of vowels in their experiments [19][20][21]23,24,[35][36][37], the vowel /a/ is still the most frequently used one. However, this choice should be supported by a complex, robust, and multilingual study (theoretically, the effect of culture and language plays no role here, but this should be proven as well).…”

“…In the field of acoustic analysis of PD phonation, the authors mostly focused on the sustained vowel /a/ [9]. Conventional phonatory features such as jitter, shimmer, harmonic-to-noise ratio, degree of unvoiced segments, and formant-based parameters extracted from this vowel have been widely used to diagnose PD [12,[19][20][21][22][23]. Although Hazan et al [24] employed analysis of sustained phonation for diagnosis of PD even in its early stage, based on the recent review [9], most of the researchers find relevant applications of the phonatory analysis especially in moderate or severe stages of this disorder.…”

“…A parametric version of this dataset has been made available for research purposes and other research teams further decreased the estimation error [25][26][27]. Another work that deals with the automatic clinical scores estimation was published by Mekyska et al [21]. In this study, they acquired sustained phonation of vowels /a/, /e/, /i/, /o/, /u/ in 84 PD patients.…”

Degree of Parkinson's disease severity estimation based on speech signal processing

“…In our previous studies [5], [20], [24] of HD in PD we mainly focused on HD quantification and identification. In our future studies we will follow our recent research in the field of objective assessment of PD [25] and focus on increasing prediction accuracy of several scales developed to rate motor (freezing of gait) and non-motor (depression, sleeping disorders, cognitive impairment) symptoms of PD.…”