Improved Estimation of Parkinsonian Vowel Quality through Acoustic Feature Assimilation.

This paper investigated the performance of a number of acoustic measures, both individually and in combination, in predicting the perceived quality of sustained vowels produced by people impaired with Parkinson's disease (PD). Sustained vowel recordings were collected from 51 PD patients before and after the administration of the Levodopa medication. Subjective ratings of the overall vowel quality were garnered using a visual analog scale. These ratings served to benchmark the effectiveness of the acoustic measures. Acoustic predictors of the perceived vowel quality included the harmonics-to-noise ratio (HNR), smoothed cepstral peak prominence (CPP), recurrence period density entropy (RPDE), Gammatone frequency cepstral coefficients (GFCCs), linear prediction (LP) coefficients and their variants, and modulation spectrogram features. Linear regression (LR) and support vector regression (SVR) models were employed to assimilate multiple features. Different feature dimensionality reduction methods were investigated to avoid model overfitting and enhance the prediction capabilities for the test dataset. Results showed that the RPDE measure performed the best among all individual features, while a regression model incorporating a subset of features produced the best overall correlation of 0.80 between the predicted and actual vowel quality ratings. This model may therefore serve as a surrogate for auditory-perceptual assessment of Parkinsonian vowel quality. Furthermore, the model may offer the clinician a tool to predict who may benefit from Levodopa medication in terms of enhanced voice quality.

A Comparison of Speech Amplification and Personal Communication Devices for Hypophonia.

Purpose This study compared the performance of three amplification devices hypothesized to improve speech communication in individuals with hypophonia (HP), as well as to identify individuals' device preferences. Method Twenty-two individuals with HP and their primary communication partners participated in a cross-over design study comparing three different speech amplification devices: a wired portable amplifier (Device A), a wireless stationary amplifier (Device B), and a one-way personal communication system (Device C). Participants attended one laboratory visit followed by 1-week trial periods with each device. At the first visit, HP participants completed speech tasks with and without the devices, in quiet and in noise. Following the in-laboratory test period, participants trialed each device at home for approximately 1 week per device. Following completion of the study, participants indicated whether or not they would like to continue using a device. Results Overall, in the presence of noise, all three devices demonstrated significant improvements in speech-to-noise levels and speech intelligibility compared to no device. A clear device hierarchy emerged such that the personal communication device (Device C) was associated with significantly better speech outcomes compared to the other two devices. The majority of participants elected to continue using a device at the completion of the study. Device preferences, however, did not clearly reflect the objective device hierarchy that was found for the objective speech measures. Each of the three devices was selected as a preferred device by at least three participants at the completion of the study. Conclusion Results from this study demonstrated clear differences in device performance in three distinct forms of amplification devices for individuals with HP. Findings suggest that amplification device use may be beneficial for this clinical population and underscore the potential to improve device availability and device selection criteria in future research. Supplemental Material https://doi.org/10.23641/asha.12735875.

Voice quality severity and responsiveness to levodopa in Parkinson's disease.

The effect of levodopa on perceptual and acoustic measures of voice quality was examined in fifty-one individuals with Parkinson's disease (IWPD). IWPDs produced prolonged vowels while on and off levodopa. Acoustic measures included jitter, shimmer, harmonic-to-noise ratio, cepstral peak prominence and the Acoustic Voice Quality Index. A perceptual measure of overall voice quality was obtained from 3 listeners. When the IWPDs were examined as a group, no significant difference was found between on and off levodopa conditions. In contrast, when IWPDs were split into two groups based on voice quality severity, a significant group-by-medication state interaction emerged. In addition, there was a significant correlation (r = .55) between the magnitude of levodopa-related improvement in perceived voice quality and voice quality severity. In contrast, levodopa-related improvement in voice quality was not correlated with duration of disease or levodopa use. Results do not support the hypothesis of reduced levodopa-responsiveness to voice symptoms as disease duration increases. Instead, the results suggest that the magnitude of the levodopa response may increase with increasing severity of the voice quality symptoms. These results suggest that the severity of speech and voice symptoms needs to be given greater consideration in future studies of levodopa effectiveness in IWPDs.