Vowel reduction across tasks for male speakers of American English

Effects of Deep-Brain Stimulation on Speech: Perceptual and Acoustic Data

PURPOSE

This study examined speech changes induced by deep-brain stimulation (DBS) in speakers with Parkinson's disease (PD) using a set of auditory-perceptual and acoustic measures.

METHOD

Speech recordings from nine speakers with PD and DBS were compared between DBS-On and DBS-Off conditions using auditory-perceptual and acoustic analyses. Auditory-perceptual ratings included voice quality, articulation precision, prosody, speech intelligibility, and listening effort obtained from 44 listeners. Acoustic measures were made for voicing proportion, second formant frequency slope, vowel dispersion, articulation rate, and range of fundamental frequency and intensity.

RESULTS

No significant changes were found between DBS-On and DBS-Off for the five perceptual ratings. Four of six acoustic measures revealed significant differences between the two conditions. While articulation rate and acoustic vowel dispersion increased, voicing proportion and intensity range decreased from the DBS-Off to DBS-On condition. However, a visual examination of the data indicated that the statistical significance was mostly driven by a small number of participants, while the majority did not show a consistent pattern of such changes.

CONCLUSIONS

Our data, in general, indicate no-to-minimal changes in speech production ensued from DBS stimulation. The findings are discussed with a focus on large interspeaker variability in PD in terms of their speech characteristics and the potential effects of DBS on speech.

Criteria for creating new standard reading passages for the assessment of speech and voice: A Delphi consensus study

Standard reading passages allow for the study of the integrated functions of speech and voice components in contextual, running speech, with target stimuli in a controlled environment. In both clinical practice and research, these texts provide rapid insight into the characteristics of the patient's speech, with fewer hesitations than in conversational speech and better predictability by the evaluator. Although a plethora of texts exist in different languages, they present various limitations. A specifically created standardised text in each language allowing for an ecological assessment of speech and voice functions, meeting most required criteria for standard speech and voice assessment and adapted to the target language's cultural and linguistic specificities, would therefore be an interesting option. However, no guidelines exist for the creation of such a reading passage. This article describes the international Delphi consensus study carried out to identify a minimal set of criteria to take into account when creating standard reading passages for an overall speech and voice assessment in adolescents and adults. This survey was conducted in three consecutive rounds; forty experts participated in the first round, with a total dropout of 17% from round 1 to round 3. It results in a minimal set of ten criteria which were selected by a majority of the experts and were rated as most important. This set contains five phoneme-level, two word-level, two sentence-level criteria and one global-level criterion. It can be used as a general guideline for the creation of standard reading passages in Indo-European Romance and Germanic languages such as English, French and German. The construction of a new reading passage in French following this guideline is briefly described.

Assessment of adult speech disorders: current situation and needs in French-speaking clinical practice

INTRODUCTION

Speech assessment methods used in clinical practice are varied and mainly perceptual and motor. Reliable assessment of speech disorders is essential for the tailoring of the patient's treatment plan.

OBJECTIVE

To describe current clinical practices and identify the shortcomings and needs reported by French-speaking clinicians regarding the assessment of speech disorders in adult patients.

METHODS

Data were collected using an online questionnaire for French-speaking speech and language pathologists (SLPs) in Belgium, France, Switzerland, Luxembourg, and Maghreb. Forty-nine questions were grouped into six domains: participant data, educational and occupational background, experience with speech disorders, patient population, tools and tasks for speech assessment, and possible lacks regarding the current assessment of speech disorders.

RESULTS

Responses from 119 clinicians were included in the analyses. SLPs generally use "à la carte" assessment with a large variety of tasks and speech samples. About one quarter of them do not use existing assessment batteries. Those who do mostly use them partially. Pseudo-words are rarely used and are absent from standardized batteries, in contrast to the major use of words and sentences. Perceptual evaluation largely prevails (mainly overall ratings of speech "intelligibility", "severity," and "comprehensibility" and percent-correct phonemes), whereas the recording equipment for acoustic measures is not standardized and only scarcely described by the SLPs. The most commonly used questionnaire to assess the functional impact of the speech disorder is the Voice Handicap Index; one quarter of the SLPs does not use any questionnaire. Overall, the available tools are considered only moderately satisfactory. The main reported shortcomings are a lack of objectivity and reproducibility of speech measures; exhaustiveness and consideration of specific speech parameters (prosody, speech rate, and nasality); practicality of the assessment tools.

CONCLUSION

This study highlights a lack of standardization of the speech assessment in French-speaking adults and the need to offer new reliable tools for an optimized, accurate speech assessment. The automation of these tools would allow for rapid, reproducible, and accurate measures.

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

Purpose The purpose of the current study was to characterize clear speech production for speakers with and without Parkinson disease (PD) using several measures of working vowel space computed from frequently sampled formant trajectories. Method The 1st 2 formant frequencies were tracked for a reading passage that was produced using habitual and clear speaking styles by 15 speakers with PD and 15 healthy control speakers. Vowel space metrics were calculated from the distribution of frequently sampled formant frequency tracks, including vowel space hull area, articulatory-acoustic vowel space, and multiple vowel space density (VSD) measures based on different percentile contours of the formant density distribution. Results Both speaker groups exhibited significant increases in the articulatory-acoustic vowel space and VSD₁₀, the area of the outermost (10th percentile) contour of the formant density distribution, from habitual to clear styles. These clarity-related vowel space increases were significantly smaller for speakers with PD than controls. Both groups also exhibited a significant increase in vowel space hull area; however, this metric was not sensitive to differences in the clear speech response between groups. Relative to healthy controls, speakers with PD exhibited a significantly smaller VSD₉₀, the area of the most central (90th percentile), densely populated region of the formant space. Conclusions Using vowel space metrics calculated from formant traces of the reading passage, the current work suggests that speakers with PD do indeed reach the more peripheral regions of the vowel space during connected speech but spend a larger percentage of the time in more central regions of formant space than healthy speakers. Additionally, working vowel space metrics based on the distribution of formant data suggested that speakers with PD exhibited less of a clarity-related increase in formant space than controls, a trend that was not observed for perimeter-based measures of vowel space area.

Variation in /u/ fronting in the American Midwest

Previous research has suggested that a greater degree of social indexing of gender, race, and regional background is produced in linguistic contexts that promote phonetic reduction. The goal of the current study was to explore this hypothesis through an examination of the realization of an ongoing sound change in the American Midwest-/u/ fronting-as a function of four linguistic factors that contribute to phonetic reduction: lexical frequency, phonological neighborhood density, discourse mention, and speaking style. The results revealed minimal effects of the linguistic factors on the degree of /u/ fronting among talkers with greater overall advancement in the /u/ fronting change-in-progress, suggesting that the process of /u/ fronting is nearing completion among some American Midwesterners. However, the results also revealed more /u/ fronting in plain laboratory speech than in clear laboratory speech and in low-frequency, low-density words than in low-frequency, high-density words among talkers with lower overall advancement in the /u/ fronting change-in-progress. The directions of these effects are consistent with the hypothesis that social indexing is greater in reduction-promoting contexts. Further, the relative sizes of these effects suggest that speaking style contributes more to variability in social indexing than lexical properties, such as frequency and neighborhood density.

Articulatory Range of Movement in Individuals With Dysarthria Secondary to Amyotrophic Lateral Sclerosis

PURPOSE

The current study examined overall articulatory range of movement (ROM) in individuals with amyotrophic lateral sclerosis (ALS). Differential involvement of articulators was also tested using articulatory working space in individuals with varying degrees of dysarthria severity and in typically aging individuals. A strong association between overall articulatory ROM and severity measures among individuals with ALS was hypothesized. In addition, it was hypothesized that differential involvement of articulators would be detected using overall articulatory ROM measures.

METHOD

Twenty-two speakers with dysarthria secondary to ALS and 22 typically aging speakers participated. Speech intelligibility and speaking rate were used as indices of severity. Movement range and overall articulatory working space area (convex hull) of the tongue, lower lip, and jaw were each measured by electromagnetic articulography while the speakers produced the Rainbow Passage.

RESULTS

Tongue convex hull size was significantly correlated with both indices of severity. A significant interaction between articulators and groups was observed. Individuals with severe dysarthria had reduced tongue convex hull size and exaggerated lower lip convex hull size. ROM in the anterior-posterior dimension showed a more notable differential involvement pattern than ROM in the superior-inferior dimension. Results in the area under a receiver operating characteristic curve analysis revealed group-specific ROM sensitivity.

CONCLUSIONS

The findings indicate that tongue ROM is reduced in individuals with more severe dysarthria when estimated using a standardized paragraph containing all American English phonemes. The articulatory working space measure could be useful for estimating speech dysfunction in ALS. ROM of the tongue decreases, but ROM of the lower lip and jaw each increase in individuals with severe dysarthria. Differential involvement of the articulators in the anterior-posterior dimension needs to be further investigated.

Estimating Vocal Effort from the Aerodynamics of Labial Fricatives: A Feasibility Study

OBJECTIVE AND HYPOTHESIS

Vocal effort in loud voice is produced with increased subglottal pressure during vowels and increased supraglottal pressure during consonants. In the paper, our main objective is to check whether it was supported by a parallel increase in the airflow resistance of the laryngeal articulator and of the supralaryngeal articulator, here the lips.

STUDY DESIGN AND METHOD

For this comparison, our choice fell on the fricative consonants, as their production allows perfectly synchronous air pressure and airflow measurements. Also, the calculation of the real instantaneous aerodynamic resistance is possible with fricatives-as it is with vowels-whereas it is not possible with plosives. The present feasibility study on a healthy subject is based on direct subglottal and intraoral pressures and airflow measured for /f/ or /v/ and from the contiguous vowel produced in VCVCV nonsense words at different levels of intensity.

RESULTS AND CONCLUSION

The results support that the airflow resistances at the lips and that at the larynx are quite parallel. The airflow resistance at the lips during labial fricative production could provide a good picture of the laryngeal resistance during the production of continuous speech. This suggests clinical applications using both noninvasive inferred measurements of subglottal pressure variation and direct noninferred airflow measurements from more natural speech production tasks.