Acoustic properties of vowel production in Mandarin-speaking patients with post-stroke dysarthria

Left hemisphere lateralization in unilateral upper motor neuron dysarthria via quantitative acoustic analysis

This paper aimed to identify specific acoustic parameters F1, F2, and Vowel Space Area (VSA), Vowel Articulation Index (VAI), Formant Centralization Ratio (FCR) for evaluating speech in Mandarin-speaking individuals with Unilateral Upper Motor Neuron (UUMN) dysarthria. Additionally, it explored the correlation between dysarthria severity and lesion side based on these parameters and scale results. This study conducted comparative study using acoustic spectral analysis to analyze phonetic features among UUMN dysarthria (UUMND) patients and neurologically normal adults, and the Left-sided and Right-sided upper motor neuron dysarthria (UMND) groups. The Mandibular-Oral Motor Function Assessment Scale (MOMFAS) was used in the study. The acoustic parameters F1, F2 and VSA, VAI, FCR showed significant differences between individuals with UUMN dysarthria and neurologically normal adults. Comparing left-sided upper motor neuron (UMN) dysarthria patients with right-sided UMN dysarthria patients, a considerable increase in FCR was observed in the left-sided group, while VSA and VAI showed significant decreases. The mean scale score of left-sided UMN dysarthria patients was also significantly lower than that of individuals with right-sided UMN dysarthria. The severity of UUMND was more pronounced in individuals with left-sided lesions, providing supportive evidence of lateralization on the left hemisphere. The acoustic indices F1, F2 and VSA, VAI, FCR can sensitively reflect the vowel changes of UUMND patients. They could be utilized not only to describe the acoustic properties of UUMND patients but also to assess the effectiveness of rehabilitation therapy on impaired vowel articulation in such patients.

Mapping subcortical brain lesions, behavioral and acoustic analysis for early assessment of subacute stroke patients with dysarthria

Introduction

Dysarthria is a motor speech disorder frequently associated with subcortical damage. However, the precise roles of the subcortical nuclei, particularly the basal ganglia and thalamus, in the speech production process remain poorly understood.

Methods

The present study aimed to better understand their roles by mapping neuroimaging, behavioral, and speech data obtained from subacute stroke patients with subcortical lesions. Multivariate lesion-symptom mapping and voxel-based morphometry methods were employed to correlate lesions in the basal ganglia and thalamus with speech production, with emphases on linguistic processing and articulation.

Results

The present findings revealed that the left thalamus and putamen are significantly correlated with concept preparation (r = 0.64, p < 0.01) and word retrieval (r = 0.56, p < 0.01). As the difficulty of the behavioral tasks increased, the influence of cognitive factors on early linguistic processing gradually intensified. The globus pallidus and caudate nucleus were found to significantly impact the movements of the larynx (r = 0.63, p < 0.01) and tongue (r = 0.59, p = 0.01). These insights underscore the complex and interconnected roles of the basal ganglia and thalamus in the intricate processes of speech production. The lateralization and hierarchical organization of each nucleus are crucial to their contributions to these speech functions.

Discussion

The present study provides a nuanced understanding of how lesions in the basal ganglia and thalamus impact various stages of speech production, thereby enhancing our understanding of the subcortical neuromechanisms underlying dysarthria. The findings could also contribute to the identification of multimodal assessment indicators, which could aid in the precise evaluation and personalized treatment of speech impairments.

Acoustic Effects of Speaker Sex, Speech Sample, and Mandarin Tone on Vowel Production of Poststroke Spastic Dysarthria

INTRODUCTION

Vowel production in dysarthria tends to be centralized, which is affected by many factors. This study examined the acoustic effects of speaker sex, tones, and speech samples (including sustained vowels, syllables, and sentences) and their interactions on vowel production in Mandarin speakers with poststroke spastic dysarthria.

METHODS

Twenty-eight patients with poststroke spastic dysarthria (18 males, 10 females) and 21 healthy speakers (11 males, 10 females) with no significant difference in sex and age with dysarthria were recruited. They were asked to read sustained vowels /a, i, u/, 12 syllables, and 12 sentences containing three vowels in four tones (bā, bá, bǎ, bà, bī, bí, bǐ, bì, pū, pú, pǔ, pù). Multiple spectral and temporal acoustic metrics were analyzed.

RESULTS

Results showed that regardless of the speech samples or tones, vowel production was more centralized in dysarthria than healthy controls, manifested as the decrease in F1 range, F2 range, vowel space area (VSA), and vowel articulation index (VAI). A similar performance was observed for male speakers compared to females, and vowel duration in males was shorter than females. F1 range, F2 range, VSA, VAI, and vowel duration were significantly different across speech samples and tones, decreasing in the order of vowel-syllable-sentence and T3-T2-T1-T4, respectively. Interactions of group, speaker sex, speech sample, and tone were more sensitive in VAI and vowel duration.

CONCLUSION

VAI and vowel duration were recommended as the prior metrics to the assessment of vowel production. Specific influencing factors (speaker sex, speech sample, and tone) of vowel production need to be considered by speech and language pathologists in the assessment and rehabilitation.

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.

Effects of Conventional Speech Therapy with Liuzijue Qigong, a Traditional Chinese Method of Breath Training, in 70 Patients with Post-Stroke Spastic Dysarthria

BACKGROUND Post-stroke spastic dysarthria (PSSD) is a motor speech impairment that impacts patient communication and quality of life. Liuzijue Qigong (LQG), a traditional Chinese method of breath training, could serve as an effective treatment for PSSD. This study compared the effects of conventional speech therapy and conventional speech therapy combined with LQG in patients with PSSD. MATERIAL AND METHODS Seventy patients with PSSD were randomly divided into a control group (conventional speech therapy, n=35, 77.14% cerebral infarction, 22.86% cerebral hemorrhage) and experimental group (LQG combined with conventional speech therapy, n=35, 85.71% cerebral infarction, 14.29% cerebral hemorrhage). Conventional speech therapy included relaxation, breath control, organ articulation, and pronunciation training. LQG involved producing 6 different sounds (Xu, He, Hu, Si, Chui, and Xi) accompanied by breathing and body movements. Patients were treated once a day, 5 times a week, for 4 weeks. The Frenchay Dysarthria Assessment scale (FDA), speech articulation, maximum phonation time (MPT), loudness, and Montreal Cognitive Assessment scale (MoCA) were evaluated. RESULTS At 4 weeks, the experimental group showed significant improvements compared with the control group in the change of FDA (13.26±6.84 vs 18.03±5.32, P=0.028), speech articulation (63.17±22.40 vs 76.51±15.28, P=0.024), MPT (1.34±1.30 vs 3.89±3.98, P<0.001), loudness (3.46±2.74 vs 7.14±2.56, P=0.009), MoCA (19.40±3.72 vs 22.20±5.30, P=0.020), total effective rate (68.57% vs 88.57%, P=0.041). CONCLUSIONS LQG, when combined with conventional speech therapy, enhanced the comprehensive speech ability of patients with PSSD compared with conventional treatment alone.

Consonantal Landmarks as Predictors of Dysarthria among English-Speaking Adults with Cerebral Palsy

The current study explored the possibility that the consonantal landmarks served as predictors of dysarthric speech produced by English-speaking adults with cerebral palsy (CP). Additionally, the relationship between the perceptual severity of dysarthric speech and the consonantal landmarks was explored. The analyses included 210 sentences from the TORGO database produced by seven English-speaking CP speakers with dysarthria and seven typically developing controls matched in age and gender. The results indicated that the clinical group produced more total landmark features than did the control group. A binominal regression analysis revealed that the improper control of laryngeal vibration and the inability to tactically control the energy in a voiced segment would lead to the higher likelihood of dysarthric speech. A multinominal regression analysis revealed that producing too many +v and −v landmark features would lead to higher perceptual severity levels among the CP speakers. Together with literature, the current study proposed that the landmark-based acoustic analysis could quantify the differences in consonantal productions between dysarthric and non-dysarthric speech and reflect the underlying speech motor deficits of the population in concern.

Quantitative acoustic metrics of vowel production in mandarin-speakers with post-stroke spastic dysarthria

Impairment of vowel production in dysarthria has been highly valued. This study aimed to explore the vowel production of Mandarin-speakers with post-stroke spastic dysarthria in connected speech and to explore the influence of gender and tone on the vowel production. Multiple vowel acoustic metrics, including F1 range, F2 range, vowel space area (VSA), vowel articulation index (VAI) and formant centralization ratio (FCR), were analyzed from vowel tokens embedded in connected speech produced. The participants included 25 clients with spastic dysarthria secondary to stroke (15 males, 10 females) and 25 speakers with no history of neurological disease (15 males, 10 females). Variance analyses were conducted and the results showed that the main effects of population, gender, and tone on F2 range, VSA, VAI, and FCR were all significant. Vowel production became centralized in the clients with post-stroke spastic dysarthria. Vowel production was found to be more centralized in males compared to females. Vowels in neutral tone (T0) were the most centralized among the other tones. The quantitative acoustic metrics of F2 range, VSA, VAI, and FCR were effective in predicting vowel production in Mandarin-speaking clients with post-stroke spastic dysarthria, and hence may be used as powerful tools to assess the speech performance for this population.

A Systematic Review of Measures of Dysarthria Severity in Stroke Patients

OBJECTIVE

To define methods to measure dysarthria due to stroke and guide physicians in delineating a diagnostic protocol using the best current strategies.

DESIGN

Systematic review.

LITERATURE SURVEY

A search was conducted on PubMed, EMBASE, the Cochrane Library, and Web of Science to identify measurement methods for dysarthria severity in adults after stroke.

METHODS

Two reviewers independently reviewed articles and came to a consensus about which ones to include. The authors excluded all duplicates, articles involving individuals with aphasia or other speech problems other than dysarthria, and articles unrelated to stroke. Articles were included if diagnostic measures were used to examine the effectiveness of speech rehabilitation in stroke patients.

SYNTHESIS

The search identified 1154 articles with the keywords "stroke" OR "ictus" OR "cerebral vascular accident" AND "dysarthria" OR "Speech and Language Disorders" AND "diagnosis" OR "assessment." The reviewers analyzed 86 full texts. There were 37 publications that met the criteria and were included in the systematic review. These articles were used to describe the main methods used for measuring the severity of stroke-related dysarthria before and after speech rehabilitation.

CONCLUSION

Despite the range of diagnostic tools available, robust trials are lacking, and the diagnostic approaches are always different. More research is needed to find the best diagnostic methodologies and delineate a definitive diagnostic protocol.

Dysarthria and stroke. The effectiveness of speech rehabilitation. A systematic review and meta-analysis of the studies

INTRODUCTION

Speech difficulties, such as dysarthria or aphasia, in addition to motor impairments are frequently seen in post-stroke patients.

EVIDENCE ACQUISITION

Literature searches with the keywords: "stroke" and "dysarthria" and "diagnosis" and "stroke" and "dysarthria" and "assessment" were conducted using PubMed, EMBASE, Cochrane Library, and Web of Science databases to perform the systematic review about the methods used to measure the severity of dysarthria in subjects post-stroke. The search was performed by two authors from 15 January to 22 February 2020. The research identified a total of 402 articles for the search using the keywords "stroke" and "dysarthria," and "diagnosis" and 84 references for the search using the keywords "stroke" and "dysarthria" and "assessment." Sixty-nine selected articles were analyzed by the reviewers. Thirty-seven publications met the inclusion criteria and were included in the systematic review. Thirty-two articles were excluded for several reasons: 1) 12 involved individuals with aphasia or other speech problems different from dysarthria; 2) 12 examined different topics from our aim; and 3) eight did not include post-stroke cases.

EVIDENCE SYNTHESIS

The systematic review identified methods for measuring the severity of post-stroke dysarthria. The meta-analysis showed the acoustic parameters affected in dysarthria secondary to stroke and the differences in these parameters after speech therapy.

CONCLUSIONS

The alternating and sequential motion rate (AMR- Pə, AMR-Tə, AMR-Kə, and SMR-PəTəKə) and maximum phonation time were significantly improved after speech rehabilitation.

Comparing non-native and native speech: Are L2 productions more variable?

Foreign-accented speech of second language learners is often difficult to understand for native listeners of that language. Part of this difficulty has been hypothesized to be caused by increased within-category variability of non-native speech. However, until recently, there have been few direct tests for this hypothesis. The realization of vowels and word-final stops in productions of native-English L1 speakers and native-Mandarin speakers of L2 English is compared. With the largest sample size to date, it is shown that at least proficient non-native speakers exhibit little or no difference in category variability compared to native speakers. This is shown while correcting for the effects of phonetic context. The same non-native speakers show substantial deviations from native speech in the central tendencies (means) of categories, as well as in the correlations among cues they produce. This relativizes a common and a priori plausible assumption that competition between first and second language representations necessarily leads to increased variability-or, equivalently, decreased precision, consistency, and stability-of non-native speech. Instead, effects of non-nativeness on category variability are category- and cue-specific.