Acoustic and Perceptual Consequences of Speech Cues for Mandarin Speakers With Parkinson's Disease

The Relationship Between Voice Parameters and Speech Intelligibility: A Scoping Review

OBJECTIVE

To synthesize existing evidence of the relationship between voice parameters and speech intelligibility.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Review (PRISMA-ScR) guidelines, 13 databases were searched and a manual search was conducted. A narrative synthesis of methodological quality, study characteristics, participant demographics, voice parameter categorization, and their relationship to speech intelligibility was conducted. A Grading of Recommendations Assessment, Development, and Evaluation (GRADE) assessment was also performed.

RESULTS

A total of 5593 studies were retrieved, and 30 eligible studies were included in the final scoping review. The studies were given scores of 10-25 (average 16.93) out of 34 in the methodological quality assessment. Research that analyzed voice parameters related to speech intelligibility, encompassing perceptual, acoustic, and aerodynamic parameters, was included. Validated and nonvalidated perceptual voice assessments showed divergent results regarding the relationship between perceptual parameters and speech intelligibility. The relationship between acoustic parameters and speech intelligibility was found to be complex and the results were inconsistent. The limited research on aerodynamic parameters did not reach a consensus on their relationship with speech intelligibility. Studies in which listeners were not speech-language pathologists (SLPs) far outnumbered those with SLP listeners, and research conducted in English contexts significantly exceeded that in non-English contexts. The GRADE evaluation indicated that the quality of evidence varied from low to moderate.

DISCUSSION

The results for the relationship between voice parameters and intelligibility showed significant heterogeneity. Future research should consider age-related voice changes and include diverse age groups. To enhance validity and comparability, it will be necessary to report effect sizes, tool validity, inter-rater reliability, and calibration procedures. Voice assessments should account for the validation status of tools because of their potential impact on the outcomes. The linguistic context may also influence the results.

Behavioral Management of Respiratory/Phonatory Dysfunction for Dysarthria Associated With Neurodegenerative Disease: A Systematic Review

PURPOSE

This systematic review represents an update to previous reviews of the literature addressing behavioral management of respiratory/phonatory dysfunction in individuals with dysarthria due to neurodegenerative disease.

METHOD

Multiple electronic database searches and hand searches of prominent speech-language pathology journals were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards.

RESULTS

The search yielded 1,525 articles, from which 88 met inclusion criteria and were reviewed by two blinded co-investigators. A large range of therapeutic approaches have been added to the evidence base since the last review, including expiratory muscle strength training, singing, and computer- and device-driven programs, as well as a variety of treatment modalities, including teletherapy. Evidence for treatment in several different population groups-including cerebellar ataxia, myotonic dystrophy, autosomal recessive spastic ataxia of Charlevoix-Saguenay, Huntington's disease, multiple system atrophy, and Lewy body dementia-were added to the current review. Synthesis of evidence quality provided strong evidence in support of only one behavioral intervention: Lee Silverman Voice Treatment Program (LSVT LOUD) in people with Parkinson's disease. No other treatment approach or population included in this review demonstrated more than limited evidence, reflecting that these approaches/populations require urgent further examination.

CONCLUSION

Suggestions about where future research efforts could be significantly strengthened and how clinicians can apply research findings to their practice are provided.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24964473.

Revisiting Dysarthria Treatment Across Languages: The Hybrid Approach

PURPOSE

Ten years after Miller and Lowit's (2014) groundbreaking book providing a cross-linguistic perspective on motor speech disorders, we ask where we are regarding dysarthria treatment across languages in two specific populations: adults with Parkinson's disease (PD) and children with cerebral palsy (CP).

METHOD

In this commentary, we consider preliminary evidence for both language-independent and language-specific approaches to treatment and propose a hybrid approach to speech treatment across languages, centered on the individual with dysarthria who speaks any given language.

CONCLUSIONS

Treatment research on individuals with dysarthria secondary to PD and CP is advancing, but several areas remain to be explored. Next steps are suggested for addressing the paucity and complexity of cross-linguistic speech treatment research.

Raising Awareness About Language- and Culture-Specific Considerations in the Management of Dysarthria Associated With Parkinson's Disease Within the United States

PURPOSE

The purpose of this article is to raise awareness about the importance of diverting from English-centric approaches in the management of dysarthria associated with Parkinson's disease (PD) in the United States, and embracing a language- and culture-specific perspective when working with linguistically and culturally diverse populations within the context of culturally responsive, precision medicine.

METHOD

This tutorial is divided into two primary components: a critical review of language universal and language-specific characteristics of dysarthria associated with PD and their relationship with speech intelligibility, and a practical guide to culturally responsive evidence-based practice for speech-language pathologists.

CONCLUSIONS

We offer a framework for linguistically and culturally appropriate considerations when working with clients with dysarthria associated with PD. While "universal" representations of dysarthria may be part of the big picture, language-specific contributions to speakers' intelligibility should be carefully examined to maximize treatment outcomes. Additionally, an evidence-based model that fully embraces clients' wishes and values within the context of culturally responsive, precision medicine should be prioritized, a practice that may include the use of interpreters.

The Effects of Intensive Voice Treatment in Mandarin Speakers With Parkinson's Disease: Acoustic and Perceptual Findings

PURPOSE

This study investigated the effects of intensive voice treatment on subjective and objective measures of speech production in Mandarin speakers with hypokinetic dysarthria.

METHOD

Nine Mandarin speakers with hypokinetic dysarthria due to Parkinson's disease received 4 weeks of intensive voice treatment (4 × 60 min per week). The speakers were recorded reading a passage before treatment (PRE), immediately after treatment (POST), and at 6-month follow-up (FU). Listeners (n = 15) rated relative ease of understanding (EOU) of paired speech samples on a visual analogue scale. Acoustic analyses were performed. Changes in EOU, vocal intensity, global and local fundamental frequency (f _o) variation, speech rate, and acoustic vowel space area (VSA) were examined.

RESULTS

Increases were found in EOU and vocal intensity from PRE to POST and from PRE to FU, with no change found from POST to FU. Speech rate increased from PRE to POST, with limited evidence of an increase from PRE to FU and no change from POST to FU. No changes in global or local f _o variation or in VSA were found.

CONCLUSIONS

Intensive voice treatment shows promise for improving speech production in Mandarin speakers with hypokinetic dysarthria. Vocal intensity, speech rate, and, crucially, intelligibility, may improve for up to 6 months posttreatment. In contrast, f _o variation and VSA may not increase following the treatment.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19529017.

Exploring the Acoustic Perceptual Relationship of Speech in Parkinson's Disease

Purpose Auditory perceptual judgments are commonly used to diagnose dysarthria and assess treatment progress. The purpose of the study was to examine the acoustic underpinnings of perceptual speech abnormalities in individuals with Parkinson's disease (PD). Method Auditory perceptual judgments were obtained from sentences produced by 13 speakers with PD and five healthy older adults. Twenty young listeners rated overall ease of understanding, articulatory precision, voice quality, and prosodic adequacy on a visual analog scale. Acoustic measures associated with the speech subsystems of articulation, phonation, and prosody were obtained, including second formant transitions, articulation rate, cepstral and spectral measures of voice, and pitch variations. Regression analyses were performed to assess the relationships between perceptual judgments and acoustic variables. Results Perceptual impressions of Parkinsonian speech were related to combinations of several acoustic variables. Approximately 36%-49% of the variance in the perceptual ratings were explained by the acoustic measures indicating a modest acoustic perceptual relationship. Conclusions The relationships between perceptual ratings and acoustic signals in Parkinsonian speech are multifactorial and involve a variety of acoustic features simultaneously. The modest acoustic perceptual relationships, however, suggest that future work is needed to further examine the acoustic bases of perceptual judgments in dysarthria.

Generalized Learning of Dysarthric Speech Between Male and Female Talkers

Purpose Perceptual training is a listener-targeted means for improving intelligibility of dysarthric speech. Recent work has shown that training with one talker generalizes to a novel talker of the same sex and that the magnitude of benefit is maximized when the talkers are perceptually similar. The current study expands previous findings by investigating whether perceptual training effects generalize between talkers of different sex. Method Forty new listeners were recruited for this study and completed a pretest, familiarization, and posttest perceptual training paradigm. Historical data collected using the same three-phase protocol were included in the data analysis. All listeners were exposed to the same talker with dysarthria during the pretest and posttest phases. For the familiarization phase, listeners were exposed to one of four talkers with dysarthria, differing in sex and level of perceptual similarity to the test talker or a control talker. During the testing phases, listener transcribed phrases produced by the test talker with dysarthria. Listener transcriptions were then used to calculate a percent words correct intelligibility score. Results Multiple linear regression analysis revealed that intelligibility at posttest was not predicted by sex of the training talker. Consistent with earlier work, the magnitude of intelligibility gain was greater when the familiarization and test talkers were perceptually similar. Additional analyses revealed greater between-listeners variability in the dissimilar conditions as compared to the similar conditions. Conclusions Learning as a result of perceptual training with one talker with dysarthria generalized to another talker regardless of sex. In addition, listeners trained with perceptually similar talkers had greater and more consistent intelligibility improvement. Together, these results add to previous evidence demonstrating that learning generalizes to novel talkers with dysarthria and that perceptual training is suitable for many listeners.