Improved Estimation of Parkinsonian Vowel Quality through Acoustic Feature Assimilation

Acoustic Properties of Vowel Production in Mandarin-Speaking Patients With Parkinson Disease-Related Hypokinetic Dysarthria

OBJECTIVE

The objective of the present study is to identify acoustic parameters for speech evaluation in patients who speak Mandarin, with Parkinson disease-related hypokinetic dysarthria (PDHD).

METHODS

The authors' sample included 31 patients with PDHD and 38 neurologically normal adults in a similar age range. The authors recorded each participant articulating a list of Mandarin monosyllables that included 6 monophthong vowels (i.e., /a, i, u, ɤ, y, o/). The authors identified the vowel duration (V-dur) and formants (F1 and F2) of each vowel token. On the basis of the formants, the authors calculated and analyzed the acoustic indexes of vowel space area (VSA), vowel articulation index (VAI), and formant centralization ratio (FCR) of the vowels.

RESULTS

Compared with healthy speakers, patients with PDHD had a significantly longer vowel duration for all 6 vowels (P < 0.01). The differences in VSA, VAI, and FCR between the case and normal groups were all statistically significant.

CONCLUSIONS

Differences in vowel acoustic indexes (V-dur, VSA, VAI, and FCR) between the 2 groups revealed that these 4 indexes were sensitive to the variation in vowel production in patients with PDHD. These indexes can be used to evaluate speech intelligibility caused by impaired vowel pronunciation in patients with PDHD and the outcome of rehabilitation therapy.

Comparison of Voice Quality in Persian Parkinson Patients With Healthy Counterparts Using Cepstral Peak Prominence and Cepstral Peak Prominence-Smooth and Their Relationship With Disease Severity (UPDRS-III) and Disease Duration

INTRODUCTION

One of the earliest impairments in Parkinson's patients is speech motor dysfunction, which adversely affects the phonation subsystem (voice). To date, acoustic frequency-dependent voice features such as cepstral peak prominence (CPP) and cepstral peak prominence-smooth (CPPS) have not been examined in Persian-speaking Parkinson's patients. This study aims to compare the voice quality of Persian Parkinson's patients with healthy counterparts using CPP and CPPS, as well as to investigate the relationship of these metrics with Unified Parkinson's Disease Rating Scale-Part III (UPDRS-III) and disease duration.

METHOD

This study included 35 Persian Parkinson's patients and 35 healthy individuals. Disease severity was assessed using UPDRS-III. Speech samples (sustained vowel phonation of /ɑ/ and reading of the "Grandfather Passage") were recorded by a microphone. CPP and CPPS were extracted by Praat software.

RESULTS

The results showed that the mean CPP and CPPS in both tasks were significantly lower in the patient group compared with the healthy group (P value ≤ 0.001). Spearman correlation analysis of CPP and CPPS values in both tasks with disease severity revealed a significant negative correlation between CPP and CPPS and UPDRS-III in both tasks (P value ≤ 0.001). However, no significant correlation was observed between these indices and disease duration in any task (P value ≥ 0.001).

CONCLUSION

These cepstral indices effectively distinguish vocal differences between Persian Parkinson's patients and healthy individuals. Additionally, these indices show a significant association with disease severity, underscoring their potential utility in the early diagnosis and monitoring of Parkinson's disease progression through vocal screening, especially when combined with other medical and neurological evaluations. However, this study found no relationship between disease duration and these indices. The absence of such a correlation may be attributed to the medication regimens of the patients.

Prosody matters: Preserved prominence marking strategies in people with Parkinson's disease independent of motor status

While many studies focus on segmental variation in Parkinsonian speech, little is known about prosodic modulations reflecting the ability to adapt to communicative demands in people with Parkinson's disease (PwPD). This type of prosodic modulation is important for social interaction, and it involves modifications in speech melody (intonational level) and articulation of consonants and vowels (segmental level). The present study investigates phonetic cues of prosodic modulations with respect to different focus structures in mild dysarthric PwPD as a function of levodopa. Acoustic and kinematic speech parameters of 25 PwPD were assessed in two motor conditions. Speech production data from PwPD were collected before (medication-OFF) and after levodopa intake (medication-ON) by means of 3-D electromagnetic articulography. On the acoustic level, intensity, pitch, and syllable durations were analyzed. On the kinematic level, movement duration and amplitude were investigated. Spatio-temporal modulations of speech parameters were examined and compared across three different prosodic focus structures (out-of-focus, broad focus, contrastive focus) to display varying speech demands. Overall, levodopa had beneficial effects on motor performance, speech loudness, and pitch modulation. Acoustic syllable durations and kinematic movement durations did not change, revealing no systematic effects of motor status on the temporal domain. In contrast, there were spatial modulations of the oral articulators: tongue tip movements were smaller and lower lip movements were larger in amplitude under levodopa, reflecting a more agile and efficient articulatory movement under levodopa. Thus, respiratory-phonatory functions and consonant production improved, while syllable duration and tongue body kinematics did not change. Interestingly, prominence marking strategies were comparable between the medication conditions under investigation, and in fact, appear to be preserved in mild dysarthric PwPD.

Computerized analysis of speech and voice for Parkinson's disease: A systematic review

BACKGROUND AND OBJECTIVE

Speech impairment is an early symptom of Parkinson's disease (PD). This study has summarized the literature related to speech and voice in detecting PD and assessing its severity.

METHODS

A systematic review of the literature from 2010 to 2021 to investigate analysis methods and signal features. The keywords "Automatic analysis" in conjunction with "PD speech" or "PD voice" were used, and the PubMed and ScienceDirect databases were searched. A total of 838 papers were found on the first run, of which 189 were selected. One hundred and forty-seven were found to be suitable for the review. The different datasets, recording protocols, signal analysis methods and features that were reported are listed. Values of the features that separate PD patients from healthy controls were tabulated. Finally, the barriers that limit the wide use of computerized speech analysis are discussed.

RESULTS

Speech and voice may be valuable markers for PD. However, large differences between the datasets make it difficult to compare different studies. In addition, speech analytic methods that are not informed by physiological understanding may alienate clinicians.

CONCLUSIONS

The potential usefulness of speech and voice for the detection and assessment of PD is confirmed by evidence from the classification and correlation results.