Changes In Articulation Research Articles

Subclinical articulatory changes of vowel parameters in Korean amyotrophic lateral sclerosis patients with perceptually normal voices.

The available quantitative methods for evaluating bulbar dysfunction in patients with amyotrophic lateral sclerosis (ALS) are limited. We aimed to characterize vowel properties in Korean ALS patients, investigate associations between vowel parameters and clinical features of ALS, and analyze subclinical articulatory changes of vowel parameters in those with perceptually normal voices. Forty-three patients with ALS (27 with dysarthria and 16 without dysarthria) and 20 healthy controls were prospectively collected in the study. Dysarthria was assessed using the ALS Functional Rating Scale-Revised (ALSFRS-R) speech subscores, with any loss of 4 points indicating the presence of dysarthria. The structured speech samples were recorded and analyzed using Praat software. For three corner vowels (/a/, /i/, and /u/), data on the vowel duration, fundamental frequency, frequencies of the first two formants (F1 and F2), harmonics-to-noise ratio, vowel space area (VSA), and vowel articulation index (VAI) were extracted from the speech samples. Corner vowel durations were significantly longer in ALS patients with dysarthria than in healthy controls. The F1 frequency of /a/, F2 frequencies of /i/ and /u/, the VSA, and the VAI showed significant differences between ALS patients with dysarthria and healthy controls. The area under the curve (AUC) was 0.912. The F1 frequency of /a/ and the VSA were the major determinants for differentiating ALS patients who had not yet developed apparent dysarthria from healthy controls (AUC 0.887). In linear regression analyses, as the ALSFRS-R speech subscore decreased, both the VSA and VAI were reduced. In contrast, vowel durations were found to be rather prolonged. The analyses of vowel parameters provided a useful metric correlated with disease severity for detecting subclinical bulbar dysfunction in ALS patients.

Slow development of vocal sequences through ontogeny in wild chimpanzees (Pan troglodytes verus).

The development of the unique, hierarchical, and endless combinatorial capacity in a human language requires neural maturation and learning through childhood. Compared with most non-human primates, where combinatorial capacity seems limited, chimpanzees present a complex vocal system comprising hundreds of vocal sequences. We investigated how such a complex vocal system develops and the processes involved. We recorded 10,929 vocal utterances of 98 wild chimpanzees aged 0-55 years, from Taï National Park, Ivory Coast. We developed customized Generalized non-Linear Models to estimate the ontogenetic trajectory of four structural components of vocal complexity: utterance length, diversity, probability of panting (requiring phonation across inhalation and exhalation), and probability of producing two adjacent panted units. We found chimpanzees need 10 years to reach adult levels of vocal complexity. In three variables, the steepest increase coincided with the age of first non-kin social interactions (2-5 years), and plateaued in sub-adults (8-10 years), as individuals integrate into adult social life. Producing two adjacent panted units may require more neuromuscular coordination of the articulators, as its emergence and steepest increase appear later in development. These results suggest prolonged maturational processes beyond those hitherto thought likely in species that do not learn their vocal repertoire. Our results suggest that multifaceted ontogenetic processes drive increases in vocal structural complexity in chimpanzees, particularly increases in social complexity and neuro-muscular maturation. As humans live in a complex social world, empirical support for the "social complexity hypothesis" may have relevance for theories of language evolution. RESEARCH HIGHLIGHTS: Chimpanzees need around 10 years to develop the vocal structural complexity present in the adult repertoire, way beyond the age of emergence of every single vocal unit. Multifaceted ontogenetic processes may drive increases in vocal structural complexity in chimpanzees, particularly increases in social complexity and neuro-muscular maturation. Non-linear increases in vocal complexity coincide with social developmental milestones. Vocal sequences requiring rapid articulatory change emerge later than other vocal sequences, suggesting neuro-muscular maturational processes continue through the juvenile years.

A comparison between tongue dorsum configurations during vowel production in hypernasal speech vs typical speech

Appropriate nasalization is important for intelligible speech production and can be impacted by various disorders, including a cleft palate. Nasalization is achieved primarily through coupling the nasal and oral cavities by opening the velopharyngeal (VP) port, which introduces a variety of acoustic features. Although VP control has the primary role in nasalization, evidence suggests articulatory changes such as lip rounding (constriction) enhances acoustic features of nasality, while a downward and forward movement of the tongue dorsum in high vowels could attenuate perceptions of nasality in individuals with competent VP function. There is yet scant evidence to indicate whether such systematic changes occur in the case of VP opening. In an attempt to further understand the clinical aspect of this concept, we evaluated the tongue height and forwardness using ultrasound in three speakers with VP insufficiency (VPI) and three speakers with typical VP function to investigate the tongue configuration across two conditions. Tongue dorsum excursion and tongue positioning index were captured using Assistive Articulation Assessment (AAA) software during the production of vowels /a/ and /i/ across VCV contexts. Further results will be discussed in the meeting.

Frequency stability of articulatory and acoustic modulation functions

During speech perception, neural activity entrains with moments of high acoustic change. For example, periods of high change in speech amplitude envelope magnitude are tracked by neurons in the human superior temporal gyrus. However, it is unknown whether neural entrainment may also be driven by modulation in the articulatory domain. To locate periods of high articulatory change, a spatiotemporal modulation function (Goldstein, 2019) that quantifies change over time in global vocal tract posture can be used to investigate the potential for such entrainment. Here, the frequency patterning and stability of modulation maxima, called “pulses,” are assessed using articulatory point-tracking data. The median frequency of both articulatory and acoustic pulses is found to be only slightly higher than theta band frequencies (6i–8 Hz), at which neural entrainment with speech has been reported. Within- and between-speaker variability of inter-pulse intervals is also compared to the variability of acoustic syllable and acoustic stress foot durations. The results show that intervals between pulses are more stable than syllable and foot durations. In sum, the spatiotemporal modulation function exhibits a stable frequency profile in the articulatory and acoustic domains that could be leveraged in the neurocognitive functions at work in speech perception. [Work supported by the NIH.]

ДИФФЕРЕНЦИРОВАННЫЙ ПОДХОД К ДИАГНОСТИКЕ ОККЛЮЗИОННЫХ НАРУШЕНИЙ НА ЭТАПАХ ФУНКЦИОНАЛЬНОГО ОБСЛЕДОВАНИЯ ЖЕВАТЕЛЬНОГО АППАРАТА

Occlusion is a harmonious interaction of the dental system in dynamics, ending with the contact of teeth in conditions of their normal or disturbed ratio. This is a complex action involving teeth, masticatory muscles, TMJ. Occlusive disorders are a reflection of the external manifestations of pathological processes of the dental system. There is no doubt that in the search for etiological factors of occlusion disorders, the problem will manifest itself in one of the parts of the chewing system. The aim of the study was to optimize the early diagnosis of occlusive disorders in young patients without violating the integrity of the dentition. Materials and methods. The study included 36 patients without a violation of the integrity of the dentition aged 18 to 25 years (15 men, 21 women), who did not complain of pain in the dental system. A comprehensive dental examination was carried out and an individual "questionnaire and patient's health card" was filled out. Computer analysis with the T-Scan III occlusiography system of the company Tekscan (USA) was used to register the nature of the closing of the dentition, the study of diagnostic models in the PROTAR evo 7 KAVO articulator, as well as the study of the registration of the difference in the biopotentials of the masticatory and temporal muscles proper in patients in the phase of relative physiological rest and with maximum jaw compression using a four-channel electromyograph Synapsis NMF Neurotech (Russia). The results showed that the prevalence of occlusive disorders in the study group is 83.3%. The abnormal position of the teeth in the dentition in combination with malocclusion anomalies, non-physiological relief of the occlusal surfaces of the teeth formed due to various factors which cause the appearance of premature contacts. This prevents the harmonious sliding movements of the lower jaw and is accompanied by articulatory changes in the entire chewing system.

Single Word Intelligibility of Individuals with Parkinson's Disease in Noise: Pre-Specified Secondary Outcome Variables from a Randomized Control Trial (RCT) Comparing Two Intensive Speech Treatments (LSVT LOUD vs. LSVT ARTIC).

The majority of people with Parkinson’s disease (PD) experience both prosodic changes (reduced vocal volume, reduced pitch range) and articulatory changes (imprecise articulation) that often limit speech intelligibility and may contribute to significant declines in quality of life. We conducted a randomized control trial comparing two intensive treatments, voice (LSVT LOUD) or articulation (LSVT ARTIC) to assess single word intelligibility in the presence of background noise (babble and mall). Participants (64 PD and 20 Healthy) read words from the diagnostic rhyme test (DRT), an ANSI Standard for measuring intelligibility of speech, before and after one month (treatment or no treatment). Teams of trained listeners blindly rated the data. Speech intelligibility of words in the presence of both noise conditions improved in PD participants who had LSVT LOUD compared to the groups that had LSVT ARTIC or no treatment. Intensive speech treatment targeting prominent prosodic variables in LSVT LOUD had a positive effect on speech intelligibility at the single word level in PD.

Assessing articulatory perturbations during a sung vowel-matching exercise using articulography

Vowel matching is considered a beneficial acoustic strategy for ‘choral blend’, but little is known about the articulatory changes that occur in practice. This paper explores the use of electromagnetic articulography (EMA) to examine the articulatory modifications used by singers when asked to blend with a unison singing voice. Five choir singers were recorded sustaining vowels with EMA electrodes placed on the tongue and the lips. During this task, subjects were asked to blend to a pre-recorded stimulus (same pitch and vowel). In a control condition no stimulus was played. Vowels /ɑ, i, u/ at pitches D4, F#4 and A4 were presented in each condition in a randomised order. Fundamental frequency (fo), intensity and the first three formant frequencies were estimated from the acoustic signal and analysed alongside the synchronous EMA data. Baseline and matching conditions were compared for each recording. All subjects significantly shifted their fo in one matching condition suggesting that tuning might be their primary blending strategy. Significant differences in multiple sensor movements were only observed for the professional subject. Analysis of the trajectories of these sensor movements suggests a delay in response similar to expectation from tuning literature. EMA is shown to be a promising tool to investigate articulatory movements in addition to acoustic features of singers when blending their voice to another. These protocols will be valuable for understanding relationships between articulatory and acoustic features as voices adapt to external stimuli, which is especially applicable for vocal training and choral pedagogy.

Validation of Articulatory Rate and Imprecision Judgments in Speech of Individuals With Amyotrophic Lateral Sclerosis.

Purpose Perceptual judgments of articulatory function are commonly used by speech-language pathologists to evaluate articulatory performance in individuals with amyotrophic lateral sclerosis (ALS). The goal of this study was to evaluate the psychometric properties (e.g., reliability, validity) of these perceptual measures to inform their application as part of a comprehensive bulbar assessment tool in ALS. Method Preexisting data from 51 individuals with ALS were obtained from a larger longitudinal study. Five independent raters provided perceptual judgments of articulatory rate and imprecision in a sentence task. Inter- and intrarater reliability of these judgments were assessed. Perceptual ratings were correlated with an acoustic measure of articulatory rate, in syllables per second, obtained from passage-reading recordings. Both perceptual and acoustic measures were correlated with gold-standard kinematic tongue and jaw movement measures, recorded from sentences using electromagnetic articulography. Results The results revealed good inter- and intrarater reliability of perceptual judgments of articulatory function. Strong correlations were observed between perceptual ratings of articulatory rate and imprecision and acoustic measures of articulatory rate and kinematic measures of tongue speed. Conclusions These findings support the clinical application of perceptual judgments of articulatory function as valid and reliable measures of underlying articulatory changes in bulbar ALS. Additional research is needed to understand the responsiveness of these measures to clinical changes in articulatory function in ALS.

Acoustic differences between voiced and whispered speech in gender diverse speakers.

Whispered speech is a naturally produced mode of communication that lacks a fundamental frequency. Several other acoustic differences exist between whispered and voiced speech, such as speaking rate (measured as segment duration) and formant frequencies. Previous research has shown that listeners are less accurate at identifying linguistic information (e.g., identifying a speech sound) and speaker information (e.g., reporting speaker gender) from whispered speech. To further explore differences between voiced and whispered speech, acoustic differences were examined across three datasets (hVd, sVd, and ʃVd) and three speaker groups (ciswomen, transwomen, cismen). Consistent with previous studies, vowel duration was generally longer in whispered speech and formant frequencies were shifted higher, although the magnitude of these differences depended on vowel and gender. Despite the increase in duration, the acoustic vowel space area (measured either with a vowel quadrilateral or with a convex hull) was smaller in the whispered speech, suggesting that larger vowel space areas are not an automatic consequence of a lengthened articulation. Overall, these findings are consistent with previous literature showing acoustic differences between voiced and whispered speech beyond the articulatory change of eliminating fundamental frequency.

Locating de-lateralization in the pathway of sound changes affecting coda /l/

‘Vocalization’ is a label commonly used to describe an ongoing change in progress affecting coda /l/ in multiple accents of English. The label is directly linked to the loss of consonantal constriction observed in this process, but it also implicitly signals a specific type of change affecting manner of articulation from consonant to vowel, which involves loss of tongue lateralization, the defining property of lateral sounds. In this study, we consider two potential diachronic pathways of change: an abrupt loss of lateralization which follows from the loss of apical constriction, versus slower gradual loss of lateralization that tracks the articulatory changes to the dorsal component of /l/. We present articulatory data from seven speakers of New Zealand English, acquired using a combination of midsagittal and lateral EMA, as well as midsagittal ultrasound. Different stages of sound change are reconstructed through synchronic variation between light, dark, and vocalized /l/, induced by systematic manipulation of the segmental and morphosyntactic environment, and complemented by comparison of different individual articulatory strategies. Our data show a systematic reduction in lateralization that is conditioned by increasing degrees of /l/-darkening and /l/-vocalization. This observation supports the idea of a gradual diachronic shift and the following pathway of change: /l/-darkening, driven by the dorsal gesture, precipitates some loss of lateralization, which is followed by loss of the apical gesture. This pathway indicates that loss of lateralization is an integral component in the changes in manner of articulation of /l/ from consonantal to vocalic.

Tongue- and Jaw-Specific Articulatory Changes and Their Acoustic Consequences in Talkers With Dysarthria due to Amyotrophic Lateral Sclerosis: Effects of Loud, Clear, and Slow Speech.

Purpose This study aimed to determine how tongue and jaw displacement changes impact acoustic vowel contrast in talkers with amyotrophic lateral sclerosis (ALS) and controls. Method Ten talkers with ALS and 14 controls participated in this study. Loud, clear, and slow speech cues were used to elicit tongue and jaw kinematic as well as acoustic changes. Speech kinematics was recorded using three-dimensional articulography. Independent tongue and jaw displacements were extracted during the diphthong /ai/ in kite. Acoustic distance between diphthong onset and offset in Formant 1-Formant 2 vowel space indexed acoustic vowel contrast. Results In both groups, all three speech modifications elicited increases in jaw displacement (typical < slow < loud < clear). By contrast, only slow speech elicited significantly increased independent tongue displacement in the ALS group (typical = loud = clear < slow), whereas all three speech modifications elicited significantly increased independent tongue displacement in controls (typical < loud < clear = slow). Furthermore, acoustic vowel contrast significantly increased in response to clear and slow speech in the ALS group, whereas all three speech modifications elicited significant increases in acoustic vowel contrast in controls (typical < loud < slow < clear). Finally, only jaw displacements accounted for acoustic vowel contrast gains in the ALS group. In controls, however, independent tongue displacements accounted for increases in vowel acoustic contrast during loud and slow speech, whereas jaw and independent tongue displacements accounted equally for acoustic vowel contrast change during clear speech. Conclusion Kinematic findings suggest that slow speech may be better suited to target independent tongue displacements in talkers with ALS than clear and loud speech. However, given that gains in acoustic vowel contrast were comparable for slow and clear speech cues in these talkers, future research is needed to determine potential differential impacts of slow and clear speech on perceptual measures, such as intelligibility. Finally, findings suggest that acoustic vowel contrast gains are predominantly jaw driven in talkers with ALS. Therefore, the acoustic and perceptual consequences of direct instructions of enhanced jaw movements should be compared to cued speech modification, such as clear and slow speech in these talkers.

Syllable duration changes during babbling: a longitudinal study of French infant productions.

At the babbling stage, the syllable does not have the temporal characteristics of adult syllables because of the infant's limited oro-motor skills. This research aims to further our knowledge of syllable duration and temporal variability and their evolution with age as an indicator of the development of articulatory skills. The possible impact of syllable position, as well as that of type of intrasyllabic associations and intersyllabic articulatory changes on these parameters has also been tested. Oral productions of 22 French infants were recorded monthly from 8 to 14 months. 11 261 Consonant-Vowel (CV) syllables were annotated and temporally analyzed. The mean duration varied according to syllable position, but not to the intrasyllabic or intersyllabic articulatory changes. Moreover, the syllable duration decreased significantly from the age of 10 months onwards, whereas the temporal variability remained the same.

Post-collection ultrasound-audio synchronization

Speech research using lingual ultrasound often requires both the ultrasound images as well as audio from the corresponding audio speech signals, but synchronization of these signals is not always available. We propose that periods of matching rates of change in the two signals could be used to align articulatory and acoustic signals where synchronization is impossible or would otherwise benefit from verification. In this study, we analyze pre-synchronized ultrasound and audio recordings of English speakers reading words. For each recording, we calculated the articulatory change as the change in pixel brightness values over time and the acoustic change as the change in Mel Frequency Cepstral Coefficient representations of the audio, and then calculated the degree of correlation between the acoustic and articulatory change over a window shifting through the recording. Then, we deliberately offset the signals in increments of 5 ms to verify that the known synchronization results in the best correlations. We manipulated several other variables, and preliminary results suggest that shorter window lengths and analyzing correlations only during detected speech result in the most accurate alignments. Analysis is ongoing to determine whether duration of correlation (number of windows with high r-values) or overall degree of correlation (median r-values) leads to the most accurate alignments.Speech research using lingual ultrasound often requires both the ultrasound images as well as audio from the corresponding audio speech signals, but synchronization of these signals is not always available. We propose that periods of matching rates of change in the two signals could be used to align articulatory and acoustic signals where synchronization is impossible or would otherwise benefit from verification. In this study, we analyze pre-synchronized ultrasound and audio recordings of English speakers reading words. For each recording, we calculated the articulatory change as the change in pixel brightness values over time and the acoustic change as the change in Mel Frequency Cepstral Coefficient representations of the audio, and then calculated the degree of correlation between the acoustic and articulatory change over a window shifting through the recording. Then, we deliberately offset the signals in increments of 5 ms to verify that the known synchronization results in the best correlations. We ...

Influence of orthodontic appliance-derived artifacts on 3-T MRI movies

BackgroundMagnetic resonance imaging (MRI) has been used to study configurations of speech organs in the resting state. However, MRI is sensitive to metals, and numerous types of metallic appliances, most of which have a large magnetic susceptibility, are used in orthodontic treatment and may cause severe artifacts on MRI. We have developed techniques for obtaining MRI movies of the oral region, to evaluate articulatory changes, especially movement of the tongue, palate, and teeth, pre- and post-orthodontic/orthognathic treatment. We evaluated the influence of artifacts caused by orthodontic appliances, including fixed retainers, metal brackets, and wires, on measurements in 3-T MRI movies.MethodsSixteen healthy young adults (nine males, seven females; average age, 27 years) with normal occlusion were recruited. Four types of customized maxillary and mandibular plates were prepared by incorporating one of the following into the plate: (a) nothing, (b) a fixed canine-to-canine retainer, (c) metal brackets for the anterior and molar teeth, or (d) clear brackets for the anterior teeth and metal brackets for molars. A 3-T MRI movie, in segmented cine mode, was generated for each plate condition while participants pronounced a vowel-consonant-vowel syllable (/asa/). The size of the artifact due to the metallic brackets was measured. The face size and orthodontically important anatomical structures, such as the velum, the hard palate, and the laryngeal ventricle, were also measured.ResultsA large artifact was observed over the entire oral region around orthodontic appliances, altering regional visibility. The velopharyngeal height was measured as significantly longer in the presence of metal brackets. The maximum artifact size due to a metallic bracket was > 8 cm. Our results show that even if it is possible to obtain the measurements of palate length, nasion to sella, and nasion to basion in individuals wearing metal brackets for molars, the measurements might be affected due to the presence of artifacts.ConclusionsOrthodontic appliances, including metallic materials, sometimes produce significant measurement error in speech evaluation using MRI movies, which often become invisible or distorted by metallic orthodontic appliances. When the distorted image is measured, caution should be exercised, as the measurement may be affected. Based on the study, it is concluded that orthodontists should not necessarily remove all metallic appliances before MRI examination because the influence varies among the appliances and should also know that a significant measurement error in speech evaluation using MRI movie may occur by image distortion caused by metallic artifacts.

Kinematic Analysis of Speech Sound Sequencing Errors Induced by Delayed Auditory Feedback.

Delayed auditory feedback (DAF) causes speakers to become disfluent and make phonological errors. Methods for assessing the kinematics of speech errors are lacking, with most DAF studies relying on auditory perceptual analyses, which may be problematic, as errors judged to be categorical may actually represent blends of sounds or articulatory errors. Eight typical speakers produced nonsense syllable sequences under normal and DAF (200 ms). Lip and tongue kinematics were captured with electromagnetic articulography. Time-locked acoustic recordings were transcribed, and the kinematics of utterances with and without perceived errors were analyzed with existing and novel quantitative methods. New multivariate measures showed that for 5 participants, kinematic variability for productions perceived to be error free was significantly increased under delay; these results were validated by using the spatiotemporal index measure. Analysis of error trials revealed both typical productions of a nontarget syllable and productions with articulatory kinematics that incorporated aspects of both the target and the perceived utterance. This study is among the first to characterize articulatory changes under DAF and provides evidence for different classes of speech errors, which may not be perceptually salient. New methods were developed that may aid visualization and analysis of large kinematic data sets. https://doi.org/10.23641/asha.5103067.

Use of H1-H2 to quantify formant tuning for notes and portions of the vibrato cycle in the second passaggio of a professional female singer

Singing voice pedagogy emphasizes that an acoustic change occurs in standard, classical, techniqued soprano voice between the musical notes D5♮ (587 Hz) and F5♮ (698 Hz). For low vowels, this involves a transition from tuning of the second resonance to the second harmonic (F2/H2) to tuning of the first resonance to the fundamental (F1/F0). In this single-subject study, we quantified the acoustics of this transition as the amplitude difference between the first and second harmonics (H1-H2). Results showed a clear and substantial change from negative to positive H1-H2 values at a pivot point between E5♭ and E5♮, implying the resonance tuning. Non-techniqued singing, with the same singer, showed no such change. F0 fluctuation (vibrato) of ±90 cent at the pivot point resulted in positive H1-H2 values at vibrato maxima and negative ones at vibrato minima. Additionally, H1-H2 values were consistently higher at vibrato maxima than minima throughout the transition area. Potential explanations for the latter result are: (i) vocal tract resonances are located just above the sung F0, or (ii) the vibrato cycle is accompanied by an articulatory change, possibly laryngeal movement. This illustrates the intricacies of formant tuning and suggests future possibilities for numerical assessment of vocal technique.

Adult Learners and a One-day Production Training – Small Changes but the Native Language Sound System Prevails

Theories and models of non-native phonetic acquisition emphasise the significance of the native sound system in the learning process. On the basis of extensive research, it is evident that the mother tongue phonology prevents the learner from perceiving redundant sound contrasts, which are of importance in the target language. These phonological difficulties are naturally reflected in the production patterns as well, and learners tend to articulate according to the native model. In this study the aim was to see, whether a short production training results in articulatory changes. For this purpose we trained native speakers of Finnish and American English to produce a non-native vowel contrast embedded in a pseudo-word context /ty:ti/ - /tʉ:ti/. We analysed the first two formants from both the baseline and after-training productions. The results showed significant group differences in the formant frequencies and in their standard deviations. These findings indicate that both groups produced the pseudo-words according to the mother tongue model and that a short training was not enough to overcome the strength of the native language sound system. However, training did reduce deviations of the formant frequencies, which implies that the learners found a more homogeneous production pattern with training.

Plasticity of the internal model for speech sounds: Articulatory changes during intensive visual biofeedback treatment

Visual biofeedback, commonly delivered by a display of ultrasound of tongue position, has demonstrated effectiveness for treating residual speech errors in older children and adults. It can be challenging to make kinematic measures during treatment without the use of a head stabilizing system, however, and it is likewise not possible to measure the changes in speech motor control that accompany improvements in speech sound production. Opti-Speech, a visual biofeedback treatment software that uses EMA to provide positional data, has the benefit of providing a steady stream of position data throughout baseline and treatment sessions. In this study, Opti-Speech treatment was provided with an intensive schedule (2x/day for 5 days) to two adolescent males with persistent speech errors (i.e., lateralized /s/). Marked improvements in /s/ accuracy and quality were noted over the course of treatment and are reported in another paper (Mental et al., this meeting). Kinematic measures were made of tongue position thr...

Articulatory Changes in Vowel Production following STN DBS and Levodopa Intake in Parkinson's Disease.

Purpose. To investigate the impact of deep brain stimulation of the subthalamic nucleus (STN DBS) and levodopa intake on vowel articulation in dysarthric speakers with Parkinson's disease (PD). Methods. Vowel articulation was assessed in seven Quebec French speakers diagnosed with idiopathic PD who underwent STN DBS. Assessments were conducted on- and off-medication, first prior to surgery and then 1 year later. All recordings were made on-stimulation. Vowel articulation was measured using acoustic vowel space and formant centralization ratio. Results. Compared to the period before surgery, vowel articulation was reduced after surgery when patients were off-medication, while it was better on-medication. The impact of levodopa intake on vowel articulation changed with STN DBS: before surgery, levodopa impaired articulation, while it no longer had a negative effect after surgery. Conclusions. These results indicate that while STN DBS could lead to a direct deterioration in articulation, it may indirectly improve it by reducing the levodopa dose required to manage motor symptoms. These findings suggest that, with respect to speech production, STN DBS and levodopa intake cannot be investigated separately because the two are intrinsically linked. Along with motor symptoms, speech production should be considered when optimizing therapeutic management of patients with PD.

A comparison of acoustic and perceptual changes in children’s productions of American English /r/

Speech-language pathologists rely primarily on their perceptual judgments when evaluating whether children have made progress in speech sound therapy. Speech sound perception in normal listeners has been characterized as largely categorical, such that slight articulatory changes may go unnoticed unless they reach a specific acoustic signature assigned to a different category. While perception may be categorical, acoustic phenomena are largely measured in continuous units, meaning that there is a potential mismatch between the two methods of recording change. Clinicians, using perceptual categorization, commonly report that some children make no progress in therapy, yet acoustically, the children’s productions may be shifting toward acceptable acoustic characteristics. Using subtle changes in the acoustic signal during therapy could potentially prevent these clients from being discharged due to a perceived lack of progress. This poster evaluates acoustic changes compared to perceptual changes in children’s productions of the American English phoneme /r/ after receiving speech therapy using ultrasound supplemented with telepractice home practice. Preliminary data indicate that there are significant differences between participants’ acoustic values of /r/ and perceptual ratings by clinicians.