Articulatory Movements Research Articles

The TDQ-60 Tr-a Picture-Naming Test to Assess Anomia in Turkish Adults and the Elderly: Normative Data and Validation Study in Alzheimer's Disease and Mild Cognitive Impairment.

Anomia is defined by difficulty in retrieving content words like nouns and verbs from long-term memory, independent of any impairments related to articulatory movements or motor speech execution. The tools for measuring picture naming, the conventional method for assessing anomia, are very limited in Turkey. The aim of this study was to adapt the Test de Dénomination de Québec-60 images/Quebec picture-naming test-60 pictures (TDQ-60), a color picture-naming test for adults and the elderly into Turkish, establish its validity, and develop normative data adapted to the Turkish population to address this gap. We conducted three separate studies. The objective of Study 1 was to culturally adapt the Test de Dénomination de Québec-60 images. In Study 2, we developed normative data for the TDQ-60 Tr adapted to the adult and elderly population in Turkey based on the performance of 414 community residents aged 18years and older. In Study 3, the known-group validity, the convergent validity, and the test-retest validity of the TDQ-60 Tr were determined. The results show that the TDQ-60 Tr is reliable in distinguishing participants with Alzheimer's disease and mild cognitive impairment from healthy participants. The TDQ-60 Tr measures the same cognitive construct as the Boston Naming Test and also has a high test-retest reliability. In summary, the TDQ-60 Tr is a valid and reliable instrument for assessing naming abilities in adults and the elderly. The results of this study have significant implications for the assessment of naming ability in Turkish-speaking patients. Our work serves as a crucial connection to address the lack of tools for diagnosing anomia in Turkey.

Disease-Specific Speech Movement Characteristics of the Tongue and Jaw.

To advance our understanding of disease-specific articulatory impairment patterns in speakers with dysarthria, this study investigated the articulatory performance of the tongue and jaw in speakers with differing neurological diseases (Parkinson's disease [PD], amyotrophic lateral sclerosis, multiple sclerosis, and Huntington's disease). Fifty-seven speakers with dysarthria and 30 controls produced the sentence "Buy Kaia a kite" five times. A three-dimensional electromagnetic articulography was used to record the articulatory movements of the posterior tongue and jaw. Sentence-length kinematic measures (e.g., duration, tongue range of motion [ROM], jaw ROM, tongue speed, jaw speed) were extracted. Results revealed significant group effects for the duration, jaw ROM, and tongue speed but not for tongue ROM. Post hoc pairwise comparisons revealed more significant between-groups differences for duration and jaw ROM than for tongue speed. Statistically significant findings between clinical groups were predominantly driven by the difference between speakers with PD and speakers of other clinical groups. Reduced jaw ROM and trends toward reduced tongue ROM confirm hypokinesia as a distinguishing motor feature of speakers with PD. However, deviancies in speed or movement duration did not emerge as a distinguishing motor feature for any of the four studied clinical groups. Nevertheless, movement duration, but not movement speed, may be useful to index dysarthria severity.

Diadochokinetic rate in Thai adults using between auditory-perceptual and instrumental methods

Background: Diadochokinetic (DDK) rate refers to the time taken to execute rapid repetitive movements of articulators during speech. DDK rate assessment has been used to screen or as part of an assessment to diagnose and plan treatment for motor speech disorders. It contained alternating motion rate (AMR) and sequential motion rate (SMR) assessments. There were two main methods for DDK assessment: perceptual speech assessment and instrumental speech assessment. Objective: This study aimed to compare the DDK rate measured by auditoryperceptual and instrumental methods and investigate the effects of age and gender on the DDK rate in normal Thai adults. Materials and methods: In this cross-sectional study, the participants were Thai adults aged 21-78. Sixty participants were divided equally into three age groups: young adult, middle-aged adult, and older adult group. All participants were asked to repeat four speech tasks as rapidly as possible, namely, AMR as [ph a:], [th a:], [kh a:], and SMR as [ph a:-th a:-kh a:]. DDK rates were measured using two methods, namely, the auditory-perceptual method and the instrumental method, which used the Praat program. The paired sample t-test examined the difference in average DDK rates between the two methods. The one-way ANOVA was utilized to analyze the average rate differences among three age groups, while gender differences were analyzed through an independent sample t-test. Results: The averages of SMR between the auditory-perceptual method and thePraat program were significantly different (p<0.05), whereas the averages of AMRwere not significantly different. The findings also found that averages of SMR hadsignificant differences (p<0.05) between three age groups and two genders. The young adult group had a higher average of SMR than middle-aged adult and olderadult groups. Males had a higher average of SMR than females. Conclusion: This result indicates that different assessment methods result in different DDK rates, especially SMR. Therefore, choosing the DDK rate assessment method should be careful and consider its accuracy. Moreover, the SMR task may be more sensitive than the AMR task to age-related change and gender factors.

Does sound symbolism need sound?: The role of articulatory movement in detecting iconicity between sound and meaninga).

Ever since de Saussure [Course in General Lingustics (Columbia University Press, 1916)], theorists of language have assumed that the relation between form and meaning of words is arbitrary. However, recently, a body of empirical research has established that language is embodied and contains iconicity. Sound symbolism, an intrinsic link language users perceive between word sound and properties of referents, is a representative example of iconicity in language and has offered profound insights into theories of language pertaining to language processing, language acquisition, and evolution. However, on what basis people detect iconicity between sound and meaning has not yet been made clear. One way to address this question is to ask whether one needs to be able to hear sound to detect sound symbolism. Here, it is shown that (1) deaf-and-Hard-of-Hearing (DHH) participants, even those with profound hearing loss, could judge the sound symbolic match between shapes and words at the same level of accuracy as hearing participants do; and (2) restriction of articulatory movements negatively affects DHH individuals' judgments. The results provided support for the articulatory theory of sound symbolism and lead to a possibility that linguistic symbols may have emerged through iconic mappings across different sensory modality-in particular, oral gesture and sensory experience of the world in the case of speech.

Real-time MRI articulatory movement database and its application to articulatory phonetics

Real-time MRI articulatory movement database and its application to articulatory phonetics

Implementasi Metode talaqqi dalam Proses Pembelajaran Hafalan Al-Qur’an Siswa SD Al-Qur’an Wahdah Islamiyah Polewali

The purpose of this research is to find out how the talaqqi method is implemented in the Al-Qur'an memorization learning process for students at Wahdah Islamiyah Polewali Al-Qur'an Elementary School and to find out the supporting and inhibiting factors in implementing the talaqqi method in the Al-Qur memorization learning process. 'an student at SD Al-Qur'an Wahdah Islamiyah Polewali. This type of research is a type of qualitative descriptive research, which is a descriptive analysis of data obtained in the form of words, images or behavior and provides an overview of the conditions studied in the form of a narrative description. The implementation of the talaqqi method in schools is going well with the steps for implementing it, namely: the ustadzah explains, then gives an example of the verse to be memorized with clear articulation and mouth movements, then students imitate the ustadzah's reading. Supporting factors include: Islamic elementary schools, appropriate leaders, qualified teachers, collaboration between teachers, understanding and application of Tajwid rules, mastery of methods, as well as students as objects and their readiness to memorize. Inhibiting factors are teacher indiscipline, less than optimal application of methods, lack of teacher concern for student memorization, student difficulty in pronouncing letters, student indiscipline and less conducive space.

Differential weighting of information during aloud and silent reading: Evidence from representational similarity analysis of fMRI data

Abstract Single word reading depends on multiple types of information processing: readers must process low-level visual properties of the stimulus, form orthographic and phonological representations of the word, and retrieve semantic content from memory. Reading aloud introduces an additional type of processing wherein readers must execute an appropriate sequence of articulatory movements necessary to produce the word. To date, cognitive and neural differences between aloud and silent reading have mainly been ascribed to articulatory processes. However, it remains unclear whether articulatory information is used to discriminate unique words, at the neural level, during aloud reading. Moreover, very little work has investigated how other types of information processing might differ between the two tasks. The current work used representational similarity analysis (RSA) to interrogate fMRI data collected while participants read single words aloud or silently. RSA was implemented using a whole-brain searchlight procedure to characterize correspondence between neural data and each of five models representing a discrete type of information. Both conditions elicited decodability of visual, orthographic, phonological, and articulatory information, though to different degrees. Compared with reading silently, reading aloud elicited greater decodability of visual, phonological, and articulatory information. By contrast, silent reading elicited greater decodability of orthographic information in right anterior temporal lobe. These results support an adaptive view of reading whereby information is weighted according to its task relevance, in a manner that best suits the reader’s goals.

Generalization of Interarticulator Timing Control: Evidence From Tongue-Jaw and Lip-Jaw Kinematics Using Electromagnetic Articulography.

In skilled speech production, the motor system coordinates the movements of distinct sets of articulators to form precise and consistent constrictions in the vocal tract at distinct locations, across contextual variations in movement rate and amplitude. Research efforts have sought to uncover the critical control parameters governing interarticulator coordination during constriction formation, with a focus on two parameters: (a) latency of movement onset of one articulator relative to another (temporal parameters) and (b) phase angle of movement onset for one articulator relative to another (spatiotemporal parameters). Consistent interarticulator timing between jaw and tongue tip movements, during the formation of constrictions at the alveolar ridge, was previously found to scale more reliably than phase angles across variation in production rate and syllable stress. In the present study, we test whether these temporal regularities generalize to another set of articulators, namely, the jaw and lower lip, during the formation of constrictions at the lips. Eight talkers produced vowel-consonant-vowel (VCV) sequences, recorded using electromagnetic articulography, with variation in production rate and syllable stress. V was /ɑ/-/ɛ/ and C was alveolar /t/-/d/ or bilabial /p/-/b/. Two measures were obtained: (a) the timing of tongue tip/lower lip raising onset for intervocalic C, relative to jaw opening-closing cycles for the flanking vowels, and (b) the angle of tongue tip/lower lip raising onset for intervocalic C, relative to the jaw phase plane. Across both sets of articulators, consonant-related movement onset latencies scaled more consistently with variation in the jaw opening-closing cycle than phase angles. Furthermore, movement onset latencies were more strongly affiliated with utterance type than phase angles. Findings demonstrate that precise temporal coordination of articulator movements regulates the formation of precise constrictions, independent of the specific set of articulators involved or where in the vocal tract the constriction is produced.

Behavioral Response Modeling to Resolve Listener- and Stimulus-Related Influences on Audiovisual Speech Integration in Cochlear Implant Users.

Speech intelligibility is supported by the sound of a talker's voice and visual cues related to articulatory movements. The relative contribution of auditory and visual cues to an integrated audiovisual percept varies depending on a listener's environment and sensory acuity. Cochlear implant users rely more on visual cues than those with acoustic hearing to help compensate for the fact that the auditory signal produced by their implant is poorly resolved relative to that of the typically developed cochlea. The relative weight placed on auditory and visual speech cues can be measured by presenting discordant cues across the two modalities and assessing the resulting percept (the McGurk effect). The current literature is mixed with regards to how cochlear implant users respond to McGurk stimuli; some studies suggest they report hearing syllables that represent a fusion of the auditory and visual cues more frequently than typical hearing controls while others report less frequent fusion. However, several of these studies compared implant users to younger control samples despite evidence that the likelihood and strength of audiovisual integration increase with age. Thus, the present study sought to clarify the impacts of hearing status and age on multisensory speech integration using a combination of behavioral analyses and response modeling. Cochlear implant users (mean age = 58.9 years), age-matched controls (mean age = 61.5 years), and younger controls (mean age = 25.9 years) completed an online audiovisual speech task. Participants were shown and/or heard four different talkers producing syllables in auditory-alone, visual-alone, and incongruent audiovisual conditions. After each trial, participants reported the syllable they heard or saw from a list of four possible options. The younger and older control groups performed similarly in both unisensory conditions. The cochlear implant users performed significantly better than either control group in the visual-alone condition. When responding to the incongruent audiovisual trials, cochlear implant users and age-matched controls experienced significantly more fusion than younger controls. When fusion was not experienced, younger controls were more likely to report the auditorily presented syllable than either implant users or age-matched controls. Conversely, implant users were more likely to report the visually presented syllable than either age-matched controls or younger controls. Modeling of the relationship between stimuli and behavioral responses revealed that younger controls had lower disparity thresholds (i.e., were less likely to experience a fused audiovisual percept) than either the implant users or older controls, while implant users had higher levels of sensory noise (i.e., more variability in the way a given stimulus pair is perceived across multiple presentations) than age-matched controls. Our findings suggest that age and cochlear implantation may have independent effects on McGurk effect perception. Noisy encoding of disparity modeling confirms that age is a strong predictor of an individual's prior likelihood of experiencing audiovisual integration but suggests that hearing status modulates this relationship due to differences in sensory noise during speech encoding. Together, these findings demonstrate that different groups of listeners can arrive at similar levels of performance in different ways, and highlight the need for careful consideration of stimulus- and group-related effects on multisensory speech perception.

Driving Digitalization: Action Research to Innovate Pronunciation Pedagogies by Building a Virtual Voice Laboratory

This paper explores the potential of digitalization in supporting English as a Second Language (ESL) students' development of pronunciation skills through a parallel action research. The author created a Virtual Voice Laboratory (VVL) platform to innovate pronunciation pedagogies in higher education; and simultaneously conducted an ongoing action research study to examine three research questions. The questions examined the efficacy of the VVL in facilitating blended learning, self-directed practice, and self-evaluation within a pronunciation course, and its impact on student engagement, participation, and pronunciation skill development. This VVL as a tailormade digital platform was implemented with undergraduate ESL students in Hong Kong's higher education context. It enabled blended learning, wherein students engaged with the mechanics and articulatory movements essential for improving English pronunciation through self-directed practice using the VVL. Adopting an action research methodology, the study investigated the process of implementing digitalization and blended learning strategies. This was achieved through the analysis of student recordings, sound chart comparisons, and qualitative-quantitative feedback collected during a pilot study. The findings reveal nuances of student experiences, their learning trajectories, and the results from the pilot study, illuminating the impacts and outcomes facilitated by the e-learning approach. The research holds valuable implications for integrating digitalization and blended learning in language education, contributing to the ongoing scholarly dialogue on the transformative potential of technology-mediated approaches in fostering dynamic and impactful learning experiences for diverse student populations.

Temporal Coordination of Articulatory Gestures in Nonnative Onset Clusters: Evidence From American English Speakers Using Electromagnetic Articulography.

Research in cross-language speech production indicates that, although the production of nonnative consonant clusters is often difficult, speakers of American English can produce some nonnative clusters (e.g., /fn/) with high accuracy. This ease of production for select nonnative clusters may occur due to similarity of phonetic structure with native clusters (e.g., nonnative /fn/ and native /sm/ are both fricative-nasal sequences). The current study tested this hypothesis by examining the extent of transfer of articulatory coordination from phonetically similar native onset clusters (i.e., /fl/, /sm/) to nonnative /fn/ clusters. Using electromagnetic articulography, lip, tongue, and jaw movements were recorded in nine participants during the production of 22 nonwords (eight tokens per nonword) containing the native and nonnative clusters in different carrier phrases. We examined the temporal lags between each consonantal gesture in a cluster and the flanking vowel gesture, which were compared to the matched singleton conditions. Analyses revealed that, as in native speech, when the syllable onset became more complex (i.e., CV ➔ CCV [C as consonant, V as vowel]), there was an increase in lag (less temporal overlap) between the leftmost consonantal gesture and the vocalic gesture, whereas there was a decrease in lag (more temporal overlap) between the rightmost consonant and the vocalic gesture (i.e., C-center timing). However, the segmental makeup of the cluster and type of carrier phrase used were also found to influence this change in temporal organization, raising new questions for future research. By and large, the findings are in agreement with the idea that the temporal coordination of articulator movements may be transferred from native clusters to phonetically similar nonnative clusters. However, kinematic measures of a broader range of nonnative clusters in different contexts are needed to fully explore this position.

Tongue bracing for improved control of vocal-tract model

We have developed a series of physical models of the human vocal tract and sound sources for different purposes, including education, speech and language pathology, scientific studies, and many other applications. Some of the models have dynamic aspects of speech production and can simulate articulatory movements. When the tongue of a dynamic model approaches the palate, tongue bracing helps to form a midline groove on the surface of the tongue, especially for high vowels. Recently, we have fine-tuned the design of our version of Umeda and Teranishi’s (UT) model to simulate continuous speech production. For the series of UT models, a set of plates or blocks line up next to each other to simulate the lower lip and tongue. The movements of these plates/blocks simulate the articulatory gestures. In the new model, the lateral and midline portions of each block for the tongue can be controlled independently. This allows us to achieve tongue bracing and eventually minimizes errors between the target and the actual positions of the blocks with quick motions.

Targeted deep brain stimulation of the motor thalamus improves speech and swallowing motor functions after cerebral lesions.

Speech and swallowing are complex motor acts that depend upon the integrity of input neural signals from motor cortical areas to control muscles of the head and neck. Lesions damaging these neural pathways result in weakness of key muscles causing dysarthria and dysphagia, leading to profound social isolation and risk of aspiration and suffocation. Here we show that Deep Brain Stimulation (DBS) of the motor thalamus improved speech and swallowing functions in two participants with dysarthria and dysphagia. First, we proved that DBS increased excitation of the face motor cortex, augmenting motor evoked potentials, and range and speed of motion of orofacial articulators in n = 10 volunteers with intact neural pathways. Then, we demonstrated that this potentiation led to immediate improvement in swallowing functions in a patient with moderate dysphagia and profound dysarthria as a consequence of a traumatic brain lesion. In this subject and in another with mild dysarthria, we showed that DBS immediately ameliorated impairments of respiratory, phonatory, resonatory, and articulatory control thus resulting in a clinically significant improvement in speech intelligibility. Our data provide first-in-human evidence that DBS can be used to treat dysphagia and dysarthria in people with cerebral lesions.

EXPRESS: Prior multisensory learning can facilitate auditory-only voice-identity and speech recognition in noise.

Seeing the visual articulatory movements of a speaker, while hearing their voice, helps with understanding what is said. This multisensory enhancement is particularly evident in noisy listening conditions. Multisensory enhancement also occurs even in auditory-only conditions: auditory-only speech and voice-identity recognition is superior for speakers previously learned with their face, compared to control learning; an effect termed the "face-benefit". Whether the face-benefit can assist in maintaining robust perception in increasingly noisy listening conditions, similar to concurrent multisensory input, is unknown. Here, in two behavioural experiments, we examined this hypothesis. In each experiment, participants learned a series of speakers' voices together with their dynamic face, or control image. Following learning, participants listened to auditory-only sentences spoken by the same speakers and recognised the content of the sentences (speech recognition, Experiment 1) or the voice-identity of the speaker (Experiment 2) in increasing levels of auditory noise. For speech recognition, we observed that 14/30 participants (47%) showed a face-benefit. While 19/25 participants (76%) showed a face-benefit for voice-identity recognition. For those participants who demonstrated a face-benefit, the face-benefit increased with auditory noise levels. Taken together, the results support an audio-visual model of auditory communication and suggest that the brain can develop a flexible system in which learned facial characteristics are used to deal with varying auditory uncertainty.

The encoding of prominence relations in supra-laryngeal articulation across speaking styles

Speakers modify their supra-laryngeal articulation on the one hand as a function of prosodic prominence and on the other hand as a function of speaking style. Articulatory movements are spatio-temporally expanded in words that are highlighted due to prosodic strengthening, but also in utterances that are produced in a loud speaking style. What remains unclear, to date, is how these two phenomena interact, or, in other words, how prominence relations are encoded in loud speech. In this paper, we use electromagnetic articulography to investigate lip and tongue kinematics and analyze selected acoustic parameters across several focus conditions in habitual and loud speech. Prosodic prominence relations are studied as the simultaneous strengthening of highlighted words and the attenuation of words in the background. The results show that prominence relations can be encoded multidimensionally in loud speech. Some modifications are even stronger in loud speech than in habitual speech, despite the general articulatory modifications associated with a loud speaking style. In both speaking styles, the attenuation of words in the background tends to be more robust than the strengthening of highlighted words. The paper underlines the flexibility of the multidimensional phonetic space in the encoding of prosodic prominence across varying communicative demands.

Immediate auditory feedback regulates inter-articulator speech coordination in service to phonetic structure.

Research has shown that talkers reliably coordinate the timing of articulator movements across variation in production rate and syllable stress, and that this precision of inter-articulator timing instantiates phonetic structure in the resulting acoustic signal. We here tested the hypothesis that immediate auditory feedback helps regulate that consistent articulatory timing control. Talkers with normal hearing recorded 480 /tV#Cat/ utterances using electromagnetic articulography, with alternative V (/ɑ/-/ɛ/) and C (/t/-/d/), across variation in production rate (fast-normal) and stress (first syllable stressed-unstressed). Utterances were split between two listening conditions: unmasked and masked. To quantify the effect of immediate auditory feedback on the coordination between the jaw and tongue-tip, the timing of tongue-tip raising onset for C, relative to the jaw opening-closing cycle for V, was obtained in each listening condition. Across both listening conditions, any manipulation that shortened the jaw opening-closing cycle reduced the latency of tongue-tip movement onset, relative to the onset of jaw opening. Moreover, tongue-tip latencies were strongly affiliated with utterance type. During auditory masking, however, tongue-tip latencies were less strongly affiliated with utterance type, demonstrating that talkers use afferent auditory signals in real-time to regulate the precision of inter-articulator timing in service to phonetic structure.

The impact of Playdough games on the development of oral motor skills in preschool children with childhood apraxia of speech

The relevant challenges are the use of innovative approaches that conserve both the speech therapist’s and the child’s resources while addressing multiple goals in speech therapy. The authors of this article have adopted such an approach to develop oral motor skills, which are crucial for speech development in preschoolers, particularly those with childhood apraxia of speech. This study aimed to evaluate the effectiveness of an author-developed therapy using Playdough games for preschool children with childhood apraxia of speech. A controlled design with repeated measures was employed. The primary diagnosis of CAS was established based on clinical assessment. A comparative evaluation of two groups (control and experimental) was conducted using a developed methodology for assessing the level of manual and oral motor skills in preschool children before and after the author-developed therapy using Playdough games. Researchers discovered that the systematic use of their author-developed Playdough games positively impacted the motor skills of children with CAS. Children in the experimental group, who participated in Playdough therapy, demonstrated significant improvements in both manual and oral motor skills, increased precision and focus in movement execution, and enhanced accuracy and speed of articulatory movements. There was a reduction in delays and incorrect movement sequences during finger movement tasks. Children required less additional time and significantly less assistance from the speech therapist, indicating a positive impact of using Playdough in therapy. The following skills improved: transitions between articulatory positions, which helped children avoid coarticulation difficulties; planning of movement sequences; and smooth transitions between sounds and syllables. The practical significance of this study lies in the effectiveness of using Playdough games for significantly improving oral motor skills, movement precision, and concentration in children with childhood apraxia of speech, thereby reducing the need for additional speech therapy support

Audio–visual deepfake detection using articulatory representation learning

Advancements in generative artificial intelligence have made it easier to manipulate auditory and visual elements, highlighting the critical need for robust audio–visual deepfake detection methods. In this paper, we propose an articulatory representation-based audio–visual deepfake detection approach, ART-AVDF. First, we devise an audio encoder to extract articulatory features that capture the physical significance of articulation movement, integrating with a lip encoder to explore audio–visual articulatory correspondences in a self-supervised learning manner. Then, we design a multimodal joint fusion module to further explore inherent audio–visual consistency using the articulatory embeddings. Extensive experiments on the DFDC, FakeAVCeleb, and DefakeAVMiT datasets demonstrate that ART-AVDF obtains a significant performance improvement compared to many deepfake detection models.

Prosody matters: Preserved prominence marking strategies in people with Parkinson's disease independent of motor status.

While many studies focus on segmental variation in Parkinsonian speech, little is known about prosodic modulations reflecting the ability to adapt to communicative demands in people with Parkinson's disease (PwPD). This type of prosodic modulation is important for social interaction, and it involves modifications in speech melody (intonational level) and articulation of consonants and vowels (segmental level). The present study investigates phonetic cues of prosodic modulations with respect to different focus structures in mild dysarthric PwPD as a function of levodopa. Acoustic and kinematic speech parameters of 25 PwPD were assessed in two motor conditions. Speech production data from PwPD were collected before (medication-OFF) and after levodopa intake (medication-ON) by means of 3-D electromagnetic articulography. On the acoustic level, intensity, pitch, and syllable durations were analyzed. On the kinematic level, movement duration and amplitude were investigated. Spatio-temporal modulations of speech parameters were examined and compared across three different prosodic focus structures (out-of-focus, broad focus, contrastive focus) to display varying speech demands. Overall, levodopa had beneficial effects on motor performance, speech loudness, and pitch modulation. Acoustic syllable durations and kinematic movement durations did not change, revealing no systematic effects of motor status on the temporal domain. In contrast, there were spatial modulations of the oral articulators: tongue tip movements were smaller and lower lip movements were larger in amplitude under levodopa, reflecting a more agile and efficient articulatory movement under levodopa. Thus, respiratory-phonatory functions and consonant production improved, while syllable duration and tongue body kinematics did not change. Interestingly, prominence marking strategies were comparable between the medication conditions under investigation, and in fact, appear to be preserved in mild dysarthric PwPD.

Is the Articulatory Trajectory of Changing Syllables Important for Achieving Higher Syllable Rates Compared to Repeated Syllables?

The production of speech-like sequences composed of varying syllables has been reported to achieve higher syllable rates than the production of repeated syllables (commonly designed as sequential motion rate [SMR] and alternating motion rate [AMR] tasks, respectively). The faster rate for SMR relative to AMR sequences is explained by different interpretative hypotheses, which remain empirically unexplored. In the present study, we aimed to investigate whether the high syllable rates of SMR sequences are due to the specific sequences used in most studies that involve front-to-back articulatory movements. Syllable rates of SMR sequences composed of different articulatory trajectories (i.e., labial-alveolar-velar [/pateko/], alveolar-velar-labial [/tekopa/], and velar-labial-alveolar [/kopate/]) were compared with those of the AMR sequences /papapa/, /tetete/, and /kokoko/ in 20 participants. The results show higher syllable rates for each of the three SMR sequences as compared to AMR, suggesting that the trajectory of the articulatory movements in the sequential sequences is not the key to achieving higher syllable rates. The syllable rate advantage for SMR over AMR sequences is not explained by the articulatory trajectories included in the former task, indicating that the front-to-back movements generally included in SMR sequences (i.e., /pataka/) are not decisive in achieving a higher syllable rate.