Examination of Clear Speech in Parkinson Disease Using Measures of Working Vowel Space

Sex Differences in the Speech of Persons With and Without Parkinson's Disease

BACKGROUND

Sex differences are apparent in the prevalence and the clinical presentation of Parkinson's disease (PD), but their effects on speech have been less studied.

METHOD

Speech acoustics of persons with (34 females and 34 males) and without (age- and sex-matched) PD were examined, assessing the effects of PD diagnosis and sex on ratings of dysarthria severity and acoustic measures of phonation (fundamental frequency standard deviation, smoothed cepstral peak prominence), speech rate (net syllables per second, percent pause ratio), and articulation (articulatory-acoustic vowel space, release burst precision).

RESULTS

Most measures were affected by PD (dysarthria severity, fundamental frequency standard deviation) and sex (smoothed cepstral peak prominence, net syllables per second, percent pause ratio, articulatory-acoustic vowel space), but without interactions between them. Release burst precision was differentially affected by sex in PD. Relative to those without PD, persons with PD produced fewer plosives with a single burst: females more frequently produced multiple bursts, whereas males more frequently produced no burst at all.

CONCLUSIONS

Most metrics did not indicate that speech production is differentially affected by sex in PD. Sex was, however, associated with disparate effects on release burst precision in PD, which deserves further study.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24388666.

Infant-directed speech does not always involve exaggerated vowel distinctions: Evidence from Danish

This study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers' spontaneous speech addressed to their 11- to 24-month-old infants (infant-directed speech, IDS) and an adult experimenter (adult-directed speech, ADS). The data were collected between 2016 and 2018 in Aarhus, Denmark. Prosodic properties of Danish IDS conformed to cross-linguistic patterns, with a higher pitch, greater pitch variability, and slower articulation rate than ADS. However, an acoustic analysis of vocalic properties revealed that Danish IDS had a reduced or similar vowel space, higher within-vowel variability, raised formants, and lower degree of vowel discriminability compared to ADS. None of the measures, except articulation rate, showed age-related differences. These results push for future research to conduct theory-driven comparisons across languages with distinct phonological systems.

Order Affects Clear and Loud Speech Response

PURPOSE

The purpose of this investigation was to examine the impact of instruction order on the speech production response when adopting higher effort speaking styles, specifically loud and clear speech.

METHOD

Speech intensity, lip aperture range, and speech rate data were collected from 24 talkers who repeated the utterance "Buy Bobby a puppy" using habitual, clear, and loud speech. Participants were assigned in quasi-random fashion to one of two groups: a Clear-Loud Group (11 participants; order: habitual-clear-loud) or a Loud-Clear Group (13 participants; order: habitual-loud-clear).

RESULTS

Talkers in the Clear-Loud Group exhibited higher speech intensity during the loud style compared with those who performed the Loud-Clear Group. Furthermore, talkers in the Clear-Loud Group retained the increases lip aperture range and reductions in speech rate associated with the clear style when producing the loud style. Conversely, talkers in the Loud-Clear Group exhibited significant increases in lip aperture range between the habitual and loud styles and between the loud and clear styles. Additionally, the Loud-Clear Group exhibited a reduction in speech rate only during the clear style, as no differences in speech rate were observed between the habitual and loud styles.

CONCLUSIONS

These findings may suggest that producing a higher effort style leads to carry-over effects in subsequent styles. Future research should investigate factors that moderate the degree of order effects for both research and clinical purposes. For instance, if generalizable, the compounding carry-over effects may prove advantageous for certain clinical populations.

Effect of clear speech on acoustic measures of dysprosody in Parkinson disease for different reading tasks

PURPOSE

The purpose of the study was to determine the effect of clear speech instruction on acoustic measures of dysprosody between reading passages of differing linguistic content for speakers with and without Parkinson Disease (PD).

METHOD

Ten speakers with PD and 10 controls served as participants and read five simple and three standard reading stimuli twice. First, speakers read habitually and then following clear speech instruction. Acoustic measures of fundamental frequency variation (semitone standard deviation, STSD), articulation rate, and between-complex pause durations were calculated.

RESULT

Results indicated speakers with PD exhibited less fundamental frequency variation than controls across reading stimuli and instructions. All speakers exhibited lower STSD and longer between-complex pause durations for the standard compared to simple reading stimuli. For clear speech, all speakers reduced articulation rate and increased between-complex pause durations in both simple and standard reading stimuli. However, speakers with PD exhibited a significantly less robust reduction in articulation rate for clear speech than control speakers for all reading stimuli.

CONCLUSION

Linguistic content of reading stimuli contributes to differences in fundamental frequency variation and pause duration for all speakers. All speakers reduced articulation rate for clear speech compared to habitual instruction, but speakers with PD did so to a lesser extent than controls. Linguistic content of reading stimuli to examine dysprosody in PD should be considered for clinical application.

The Relationship Between Acoustic and Kinematic Vowel Space Areas With and Without Normalization for Speakers With and Without Dysarthria

PURPOSE

Few studies have reported on the vowel space area (VSA) in both acoustic and kinematic domains. This study examined acoustic and kinematic VSAs for speakers with and without dysarthria and evaluated effects of normalization on acoustic and kinematic VSAs and the relationship between these measures.

METHOD

Vowel data from 12 speakers with and without dysarthria, presenting with a range of speech abilities, were examined. The speakers included four speakers with Parkinson's disease (PD), four speakers with brain injury (BI), and four neurotypical (NT) speakers. Speech acoustic and kinematic data were acquired simultaneously using electromagnetic articulography during a passage reading task. Raw and normalized VSAs calculated from corner vowels /i/, /æ/, /ɑ/, and /u/ were evaluated. Normalization was achieved through z score transformations to the acoustic and kinematic data. The effect of normalization on variability within and across groups was evaluated. Regression analysis was used across speakers to assess the association between acoustic and kinematic VSAs for both raw and normalized data.

RESULTS

When evaluating the speakers as three different groups (i.e., PD, BI, and NT), normalization reduced the standard deviations within each group and changed the relative differences in average magnitude between groups. Regression analysis revealed a significant relationship between normalized, but not raw, acoustic and kinematic VSAs, after the exclusion of an outlier speaker.

CONCLUSIONS

Normalization reduces the variability across speakers, within groups, and changes average magnitudes affecting speaker group comparisons. Normalization also influences the correlation between acoustic and kinematic measures. Further investigation of the impact of normalization techniques upon acoustic and kinematic measures is warranted.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22669747.

Vowel Acoustics as Predictors of Speech Intelligibility in Dysarthria

PURPOSE

This study sought to determine if alternative vowel space area (VSA) measures (i.e., novel trajectory-based measures: vowel space hull area and vowel space density) predicted speech intelligibility to the same extent as two traditional vowel measures (i.e., token-based measures: VSA and corner dispersion) in speakers with dysarthria. Additionally, this study examined if the strength of the relationship between acoustic vowel measures and intelligibility differed based on how intelligibility was measured (i.e., orthographic transcriptions [OTs] and visual analog scale [VAS] ratings).

METHOD

The Grandfather Passage was read aloud by 40 speakers with dysarthria of varying etiologies, including Parkinson's disease (n = 10), amyotrophic lateral sclerosis (n = 10), Huntington's disease (n = 10), and cerebellar ataxia (n = 10). Token- and trajectory-based acoustic vowel measures were calculated from the passage. Naïve listeners (N = 140) were recruited via crowdsourcing to provide OTs and VAS intelligibility ratings. Hierarchical linear regression models were created to model OTs and VAS intelligibility ratings using the acoustic vowel measures as predictors.

RESULTS

Traditional VSA was the sole significant predictor of speech intelligibility for both the OTs (R 2 = .259) and VAS (R 2 = .236) models. In contrast, the trajectory-based measures were not significant predictors of intelligibility. Additionally, the OTs and VAS intelligibility ratings conveyed similar information.

CONCLUSIONS

The findings suggest that traditional token-based vowel measures better predict intelligibility than trajectory-based measures. Additionally, the findings suggest that VAS methods are comparable to OT methods for estimating speech intelligibility for research purposes.

Automated Vowel Articulation Analysis in Connected Speech Among Progressive Neurological Diseases, Dysarthria Types, and Dysarthria Severities

PURPOSE

Although articulatory impairment represents distinct speech characteristics in most neurological diseases affecting movement, methods allowing automated assessments of articulation deficits from the connected speech are scarce. This study aimed to design a fully automated method for analyzing dysarthria-related vowel articulation impairment and estimate its sensitivity in a broad range of neurological diseases and various types and severities of dysarthria.

METHOD

Unconstrained monologue and reading passages were acquired from 459 speakers, including 306 healthy controls and 153 neurological patients. The algorithm utilized a formant tracker in combination with a phoneme recognizer and subsequent signal processing analysis.

RESULTS

Articulatory undershoot of vowels was presented in a broad spectrum of progressive neurodegenerative diseases, including Parkinson's disease, progressive supranuclear palsy, multiple-system atrophy, Huntington's disease, essential tremor, cerebellar ataxia, multiple sclerosis, and amyotrophic lateral sclerosis, as well as in related dysarthria subtypes including hypokinetic, hyperkinetic, ataxic, spastic, flaccid, and their mixed variants. Formant ratios showed a higher sensitivity to vowel deficits than vowel space area. First formants of corner vowels were significantly lower for multiple-system atrophy than cerebellar ataxia. Second formants of vowels /a/ and /i/ were lower in ataxic compared to spastic dysarthria. Discriminant analysis showed a classification score of up to 41.0% for disease type, 39.3% for dysarthria type, and 49.2% for dysarthria severity. Algorithm accuracy reached an F-score of 0.77.

CONCLUSIONS

Distinctive vowel articulation alterations reflect underlying pathophysiology in neurological diseases. Objective acoustic analysis of vowel articulation has the potential to provide a universal method to screen motor speech disorders.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23681529.

Speech disorders in patients with Tongue squamous cell carcinoma: A longitudinal observational study based on a questionnaire and acoustic analysis

BACKGROUND

Speech disorders are common dysfunctions in patients with tongue squamous cell carcinoma (TSCC) that can diminish their quality of life. There are few studies with multidimensional and longitudinal assessments of speech function in TSCC patients.

METHODS

This longitudinal observational study was conducted at the Hospital of Stomatology, Sun Yat-sen University, China, from January 2018 to March 2021. A cohort of 92 patients (53 males, age range: 24-77 years) diagnosed with TSCC participated in this study. Speech function was assessed from preoperatively to one year postoperatively using the Speech Handicap Index questionnaire and acoustic parameters. The risk factors for postoperative speech disorder were analyzed by a linear mixed-effects model. A t test or Mann‒Whitney U test was applied to analyze the differences in acoustic parameters under the influence of risk factors to determine the pathophysiological mechanisms of speech disorders in patients with TSCC.

RESULTS

The incidence of preoperative speech disorders was 58.7%, which increased up to 91.4% after surgery. Higher T stage (P＜0.001) and larger range of tongue resection (P = 0.002) were risk factors for postoperative speech disorders. Among the acoustic parameters, F2/i/decreased remarkably with higher T stage (P = 0.021) and larger range of tongue resection (P = 0.009), indicating restricted tongue movement in the anterior-posterior direction. The acoustic parameters analysis during the follow-up period showed that F1 and F2 were not significantly different of the patients with subtotal or total glossectomy over time.

CONCLUSIONS

Speech disorders in TSCC patients is common and persistent. Less residual tongue volume led to worse speech-related QoL, indicating that surgically restoring the length of the tongue and strengthening tongue extension postoperatively may be important.

Examining vocal attractiveness through articulatory working space

Robust gender differences exist in the acoustic correlates of clearly articulated speech, with females, on average, producing speech that is acoustically and phonetically more distinct than that of males. This study investigates the relationship between several acoustic correlates of clear speech and subjective ratings of vocal attractiveness. Talkers were recorded producing vowels in /bVd/ context and sentences containing the four corner vowels. Multiple measures of working vowel space were computed from continuously sampled formant trajectories and were combined with measures of speech timing known to co-vary with clear articulation. Partial least squares regression (PLS-R) modeling was used to predict ratings of vocal attractiveness for male and female talkers based on the acoustic measures. PLS components that loaded on size and shape measures of working vowel space-including the quadrilateral vowel space area, convex hull area, and bivariate spread of formants-along with measures of speech timing were highly successful at predicting attractiveness in female talkers producing /bVd/ words. These findings are consistent with a number of hypotheses regarding human attractiveness judgments, including the role of sexual dimorphism in mate selection, the significance of traits signalling underlying health, and perceptual fluency accounts of preferences.

The Impact of Clear Speech on the Perceptual and Acoustic Properties of Fricative-Vowel Sequences in Speakers With Dysarthria

Purpose Studies have reported that clear speech has the potential to influence suprasegmental and segmental aspects of speech, in both healthy and dysarthric speakers. While the impact of clear speech has been studied on the articulation of individual segments, few studies have investigated its effects on coarticulation with multisegment sequences such as fricative-vowel. Objectives The goals of this study are to investigate, in healthy and dysarthric speech, the impact of clear speech on (a) the perception of anticipatory vowel coarticulation in fricatives and (b) the acoustic characteristics of this effect. Method Ten speakers with dysarthria secondary to idiopathic Parkinson's disease were recruited as well as 10 age- and sex-matched healthy speakers. A sentence reading task was performed in natural and clear speaking conditions. The sentences contained words with the initial fricatives /s/ and /ʃ/ preceded by /ə/ and followed by the vowels /i/, /y/, /u/, or /a/. For the perceptual measurements, five listeners were recruited and were asked to predict the upcoming word by listening only to the isolated fricative. Acoustic analyses consisted of spectral moment analysis (M1-M4) on averaged time series. Results Perceptual findings report that identification rates were improved with clear speech for the speakers with dysarthria, but only for the fricative-/i/ sequences. Error pattern analysis indicates that this improvement is associated with an increase in the roundness parameter (lip spreading) identification. Acoustic results are unclear for M1 and M3 but suggest that M2 and M4 differentiation between the rounded versus unrounded vowel contexts is increased with clear speech for the speakers with dysarthria. Discussion Taken together, these findings suggest that clear speech may improve lip coordination in dysarthric speakers with Parkinson's disease. However, the impact of clear speech on the acoustic measures of fricative spectral moments is somewhat limited. This suggests that these metrics, when taken individually, do not capture the entire complexity of fricative-vowel coarticulation.

Are Vowels Normalized After Maxillary Osteotomy? An Acoustic Study in Cleft Lip and Palate

BACKGROUND

Maxillary hypoplasia is a common skeletal condition in cleft lip and palate (CLP). Maxillary osteotomy is typically used to reposition the maxilla in CLP with maxillary hypoplasia. Previous studies have suggested that vowel articulations are adjusted postsurgically due to altered vocal tract configuration and articulatory reorganization. This acoustic study aims to investigate whether vowels are normalized postoperatively and to explore the nature of articulatory reorganization.

METHODS AND PROCEDURES

A prospective study was conducted to examine the vowel production of a group of individuals with CLP (N = 17) undergoing maxillary osteotomy and a group of normal controls (N = 20), using speech acoustic data. The data were collected at 0 to 3 months presurgery (T1), 3-months (T2), and 12-months (T3) postsurgery. General linear model repeated measures and independent t-tests were undertaken on F1, F2, and vowel space area.

RESULTS

General linear model repeated measures revealed no main effects of time for F1 (F [2, 22] = 1.094, P = 0.352), F2 (F [2, 22] = 1.269, P = 0.301), and vowel space area (F [2, 28] = 0.059, P = 0.943). Independent t-tests showed statistically significant differences (P < 0.05) for all acoustic parameters and all vowels between the CLP and the normal groups at all time points.

CONCLUSIONS

Vowels were not normalized after maxillary osteotomy despite positive anatomical changes within the oral cavity. Individuals with CLP tended to adjust their vowel articulatory gestures to match presurgical patterns. The nature of articulatory reorganization appears to be prompt, sensory-driven, complete, and permanent.

Conversation Training Therapy: Let's Talk It Through

This article introduces a novel approach to voice therapy called conversation training therapy (CTT). CTT is the first voice therapy approach to remove the therapeutic hierarchy common in most treatment programs. Rather, CTT uses patient-driven conversation as the sole stimuli in therapy to increase perceptual awareness of voice production in conversational speech. The genesis as to why CTT was developed, as well as the conceptual, theoretical, and component parts of CTT, will be explained. In addition, this article will offer examples of the language of therapy, as it applies to CTT and how to trouble-shoot if problems arise. Medical documentation relevant to CTT will also be outlined. Last, results from a recent efficacy study on CTT will be reported.

Investigating voice as a biomarker: Deep phenotyping methods for early detection of Parkinson's disease

Voice technology has grown tremendously in recent years and using voice as a biomarker has also been gaining evidence. We demonstrate the potential of voice in serving as a deep phenotype for Parkinson's Disease (PD), the second most common neurodegenerative disorder worldwide, by presenting methodology for voice signal processing for clinical analysis. Detection of PD symptoms typically requires an exam by a movement disorder specialist and can be hard to access and inconsistent in findings. A vocal digital biomarker could supplement the cumbersome existing manual exam by detecting and quantifying symptoms to guide treatment. Specifically, vocal biomarkers of PD are a potentially effective method of assessing symptoms and severity in daily life, which is the focus of the current research. We analyzed a database of PD patient and non-PD subjects containing voice recordings that were used to extract paralinguistic features, which served as inputs to machine learning models to predict PD severity. The results are presented here and the limitations are discussed given the nature of the recordings. We note that our methodology only advances biomarker research and is not cleared for clinical use. Specifically, we demonstrate that conventional machine learning models applied to voice signals can be used to differentiate participants with PD who exhibit little to no symptoms from healthy controls. This work highlights the potential of voice to be used for early detection of PD and indicates that voice may serve as a deep phenotype for PD, enabling precision medicine by improving the speed, accuracy, accessibility, and cost of PD management.

Effects of Concurrent Manual Task Performance on Connected Speech Acoustics in Individuals With Parkinson Disease

Purpose Prior investigations suggest that simultaneous performance of more than 1 motor-oriented task may exacerbate speech motor deficits in individuals with Parkinson disease (PD). The purpose of the current investigation was to examine the extent to which performing a low-demand manual task affected the connected speech in individuals with and without PD. Method Individuals with PD and neurologically healthy controls performed speech tasks (reading and extemporaneous speech tasks) and an oscillatory manual task (a counterclockwise circle-drawing task) in isolation (single-task condition) and concurrently (dual-task condition). Results Relative to speech task performance, no changes in speech acoustics were observed for either group when the low-demand motor task was performed with the concurrent reading tasks. Speakers with PD exhibited a significant decrease in pause duration between the single-task (speech only) and dual-task conditions for the extemporaneous speech task, whereas control participants did not exhibit changes in any speech production variable between the single- and dual-task conditions. Conclusions Overall, there were little to no changes in speech production when a low-demand oscillatory motor task was performed with concurrent reading. For the extemporaneous task, however, individuals with PD exhibited significant changes when the speech and manual tasks were performed concurrently, a pattern that was not observed for control speakers. Supplemental Material https://doi.org/10.23641/asha.8637008.