Speech Motor Behavior Research Articles

Amyotrophic lateral sclerosis, dysarthria, and language disorders - type of research and approaches in different areas: an integrative literature review

ABSTRACT Purpose: to identify the knowledge produced in national and international researches on speech and language disorders in Amyotrophic Lateral Sclerosis, regarding the type of research and approach in different areas. Methods: an integrative review performed on databases, using the following descriptors: Amyotrophic Lateral Sclerosis, Dysarthria, Language Disorders, Speech Production Measurement and Speech Disorders. The inclusion criteria covered articles that addressed motor speech and language disorders from 2013 to 2018, excluding duplications, and categorizing valid articles for analysis. Results: 83 articles were selected, after screening the titles and abstracts. A large scientific production from different countries and areas, mainly Speech Therapy and Neurology, was found. Most of them was clinical research (65.06%), with a main focus on speech motor disorders (42.16%), speech and language motor disorders, cognition and behavior (27.71%), and language disorders (12.06%). Conclusion: researches found were mostly clinical and aimed at determining the diagnosis of disorders in different areas of knowledge. With regard to communication, few studies have been found in Brazil, and international studies addressed high technology. The results confirmed the heterogeneous nature of the disease, which shows, in addition to motor impairment of speech, cognitive, behavioral and language impairments.

Wearable Sweat Band for Noninvasive Levodopa Monitoring.

Levodopa is the standard medication clinically prescribed to patients afflicted with Parkinson's disease. In particular, the monitoring and optimization of levodopa dosage are critical to mitigate the onset of undesired fluctuations in the patients' physical and emotional conditions such as speech function, motor behavior, and mood stability. The traditional approach to optimize levodopa dosage involves evaluating the subjects' motor function, which has many shortcomings due to its subjective and limited quantifiable nature. Here, we present a wearable sweat band on a nanodendritic platform that quantitatively monitors levodopa dynamics in the body. Both stationary iontophoretic induction and physical exercise are utilized as our methods of sweat extraction. The sweat band measures real-time pharmacokinetic profiles of levodopa to track the dynamic response of the drug metabolism. We demonstrated the sweat band's functionalities on multiple subjects with implications toward the systematic administering of levodopa and routine management of Parkinson's disease.

The Dynamics of Speech Motor Control Revealed with Time-Resolved fMRI.

Holding a conversation means that speech must be started, maintained, and stopped continuously. The brain networks that underlie these aspects of speech motor control remain poorly understood. Here we collected functional magnetic resonance imaging (fMRI) data while participants produced normal and fast rate speech in response to sequences of visually presented objects. We took a non-conventional approach to fMRI data analysis that allowed us to study speech motor behavior as it unfolded over time. To this end, whole-brain fMRI signals were extracted in stimulus-locked epochs using slice-based fMRI. These data were then subjected to group independent component analysis to discover spatially independent networks that were associated with different temporal activation profiles. The results revealed two basic brain networks with different temporal dynamics: a cortical network that was activated continuously during speech production, and a second cortico-subcortical network that increased in activity during the initiation and suppression of speech production. Additional analyses explored whether key areas involved in motor suppression such as the right inferior frontal gyrus, sub-thalamic nucleus and pre-supplementary motor area provide first-order signals to stop speech. The results reveal for the first time the brain networks associated with the initiation, maintenance, and suppression of speech motor behavior.

Abnormally increased vocal responses to pitch feedback perturbations in patients with cerebellar degeneration.

Cerebellar degeneration (CD) has deleterious effects on speech motor behavior. Recently, a dissociation between feedback and feedforward control of speaking was observed in CD: Whereas CD patients exhibited reduced adaptation across trials to consistent formant feedback alterations, they showed enhanced within-trial compensation for unpredictable formant feedback perturbations. In this study, it was found that CD patients exhibit abnormally increased within-trial vocal compensation responses to unpredictable pitch feedback perturbations. Taken together with recent findings, the results indicate that CD is associated with a general hypersensitivity to auditory feedback during speaking.

The Association Between Genetic Variation in FOXP2 and Sensorimotor Control of Speech Production.

Significant advances have been made in understanding the role of auditory feedback in sensorimotor integration for speech production. The neurogenetic basis of this feedback-based control process, however, remains largely unknown. Mutations of FOXP2 gene in humans are associated with severe deficits in speech motor behavior. The present study examined the associations between a FOXP2 common variant, rs6980093 (A/G), and the behavioral and event-related potential (ERP) responses to -50 and -200 cents pitch perturbations during vocal production in a sample of 133 Chinese adults. Behaviorally, the GG genotype was associated with significantly smaller vocal compensations for -200 cents perturbations relative to the AA and AG genotypes. Furthermore, both the AA and AG genotypes exhibited significant positive correlations between the degree of vocal compensation for -50 and -200 cents perturbations and the variability of normal voice fundamental frequency, whereas no such correlation existed for the GG genotype. At the cortical level, significantly larger P2 responses to -200 cents perturbations were associated with the GG genotype as compared to the AA and AG genotypes due to increased left-lateralized activity in the superior, middle, and inferior frontal gyrus, precentral gyrus, anterior cingulate cortex, middle temporal gyrus, and insula. The neurobehavioral responses to -50 cents perturbations, however, did not vary as a function of genotype. These findings present the first neurobehavioral evidence for an association between FOXP2 genetic variant and auditory-motor integration for vocal pitch regulation. The differential effects of FOXP2 genotypes at rs6980093 may reflect their influences on the weighting of feedback and feedforward control of speech production.

Vowel reduction across tasks for male speakers of American English.

This study examined acoustic variation of vowels within speakers across speech tasks. The overarching goal of the study was to understand within-speaker variation as one index of the range of normal speech motor behavior for American English vowels. Ten male speakers of American English performed four speech tasks including citation form sentence reading with a clear-speech style (clear-speech), citation form sentence reading (citation), passage reading (reading), and conversational speech (conversation). Eight monophthong vowels in a variety of consonant contexts were studied. Clear-speech was operationally defined as the reference point for describing variation. Acoustic measures associated with the conventions of vowel targets were obtained and examined. These included temporal midpoint formant frequencies for the first three formants (F1, F2, and F3) and the derived Euclidean distances in the F1-F2 and F2-F3 planes. Results indicated that reduction toward the center of the F1-F2 and F2-F3 planes increased in magnitude across the tasks in the order of clear-speech, citation, reading, and conversation. The cross-task variation was comparable for all speakers despite fine-grained individual differences. The characteristics of systematic within-speaker acoustic variation across tasks have potential implications for the understanding of the mechanisms of speech motor control and motor speech disorders.

Three speech sounds, one motor action: evidence for speech-motor disparity from English flap production.

The assumption that units of speech production bear a one-to-one relationship to speech motor actions pervades otherwise widely varying theories of speech motor behavior. This speech production and simulation study demonstrates that commonly occurring flap sequences may violate this assumption. In the word "Saturday," a sequence of three sounds may be produced using a single, cyclic motor action. Under this view, the initial upward tongue tip motion, starting with the first vowel and moving to contact the hard palate on the way to a retroflex position, is under active muscular control, while the downward movement of the tongue tip, including the second contact with the hard palate, results from gravity and elasticity during tongue muscle relaxation. This sequence is reproduced using a three-dimensional computer simulation of human vocal tract biomechanics and differs greatly from other observed sequences for the same word, which employ multiple targeted speech motor actions. This outcome suggests that a goal of a speaker is to produce an entire sequence in a biomechanically efficient way at the expense of maintaining parity within the individual parts of the sequence.

Normal Changes in the Speech of Older Adults: You've still got what it takes; it just takes a little longer!

AbstractThe authors reviewed the changes in speech production as a result of aging, including changes in structure and function as well as changes in motor control for speech. The following speech production processes in normal or typical aging were reviewed: breathing for speech, phonation, resonation, articulation, and fluency. Different theories of the role of motor control were reviewed, including more recent conclusions that cognition influences speech motor behavior throughout the lifespan. There are many speech changes in the communication of an older adult, but most are adaptive and do not affect good conversational speech.

Speech motor correlates of treatment-related changes in stuttering severity and speech naturalness

Participants of stuttering treatment programs provide an opportunity to evaluate persons who stutter as they demonstrate varying levels of fluency. Identifying physiologic correlates of altered fluency levels may lead to insights about mechanisms of speech disfluency. This study examined respiratory, orofacial kinematic and acoustic measures in 35 persons who stutter prior to and as they were completing a 1-month intensive stuttering treatment program. Participants showed a marked reduction in stuttering severity as they completed the treatment program. Coincident with reduced stuttering severity, participants increased the amplitude and duration of speech breaths, reduced the rate of lung volume change during inspiration, reduced the amplitude and speed of lip movements early in the test utterance, increased lip and jaw movement durations, and reduced syllable rate. A multiple regression model that included two respiratory measures and one orofacial kinematic measure accounted for 62% of the variance in changes in stuttering severity. Finally, there was a weak but significant tendency for speech of participants with the largest reductions in stuttering severity to be rated as more unnatural as they completed the treatment program. Learning outcomes: As a result of this activity, the reader will be able to (1) outline the rationale for studying speech motor correlates of treatment-related variations in fluency levels; (2) identify those speech motor behaviors that are associated with reduced stuttering severity; and (3) recognize possible reasons for the associations between speech motor behavior and stuttering severity.

Variations in articulatory movement with changes in speech task.

Studies of normal and disordered articulatory movement often rely on the use of short, simple speech tasks. However, the severity of speech disorders can be observed to vary markedly with task. Understanding task-related variations in articulatory kinematic behavior may allow for an improved understanding of normal and disordered speech motor behavior in varying communication contexts. This study evaluated how orofacial kinematic behavior varies as a function of speaking task in a group of 15 healthy male speakers. The speech tasks included a nonsense phrase with a high frequency of stop consonants, a sentence, an oral reading passage, and a spontaneous monologue. In addition, rate and intensity conditions were varied for the nonsense phrase and sentence. The articulatory positions of the upper lip, lower lip, tongue blade, and mandible were recorded, and measures reflecting (a). average features of individual movements or strokes (i.e., peak speed, distance, and duration) and (b). overall spatial variability of the articulators for each task were extracted, derived, and analyzed. Results showed a number of task- and condition-related differences in speech kinematic behavior. The most prominent result from the task comparison was that the nonsense speech task exhibited larger, faster, and longer movement strokes than the other speech tasks. For some articulators (lower lip and tongue), there were task-related differences in spatial variability. Changes in loudness and rate revealed variation in kinematic measures that were often complicated by articulator identity and task type. The results suggest that an expanded range of speech tasks and conditions may aid in the study of normal and disordered speech motor behavior.

Defining and measuring speech movement events.

A long-held view in speech research is that utterances are built up from a series of discrete units joined together. However, it is difficult to reconcile this view with the observation that speech movement waveforms are smooth and continuous. Developing methods for reliable identification of speech movement units is necessary for describing speech motor behavior and for addressing theoretically relevant questions about its organization. We describe a simple method of parsing movement signals into a series of individual movement "strokes," where a stroke is defined as the period between two successive local minima in the speed history of an articulator point, and use that method to segment speech-related movement of marker points placed on the tongue blade, tongue dorsum, lower lip, and jaw in a group of healthy young speakers. Articulator fleshpoints could be distinguished on the basis of kinematic features (i.e., peak and boundary speed, duration and distance) of the strokes they produce. Further, tongue blade and jaw fleshpoint strokes identified to temporally overlap with acoustic events identified as alveolar fricatives could be distinguished from speech strokes in general on the basis of a number of kinematic measures. Finally, the acoustic timing of alveolar fricatives did not appear to be related to the kinematic features of strokes presumed to be related to their production in any direct way. The advantages and disadvantages of this simple approach to defining movement units are discussed.

Coordination and dynamics in speech motor behavior of stutterers

Coordination and dynamics in speech motor behavior of stutterers

X-ray microbeam speech production database

A broad review of literature describing lingual function during speech shows that speaker samples per study are typically small (N<3 in more than 80% of all cases), and that speech samples, and representational and analysis conventions are highly variable. Similar conclusions can be drawn for other articulators. Thus it is fair to argue that there is still not available any valid, statistically-defensible sense of normal speech motor behavior, against which disordered articulatory behavior can be compared. Accordingly, a large-sample, 50-speaker x-ray microbeam speech database will be developed at the University of Wisconsin, incorporating point-parametrized representations of lingual, labial, mandibular, and velar movements in association with the resulting acoustic sound pressure wave, for a rich set of utterances and oral motor tasks, and lengthy recording interval (circa 18 min/speaker). The database is intended to be uniform across speakers in task inventory and descriptive kinematic framework; sufficiently accurate and deep to withstand scrutiny of variance, within and across speakers, and perhaps most importantly, an open source available for unlimited inspection and use by other speech scientists. Descriptions of the proposed speech inventory, experimental protocol, speaker sample, and timetable for database development will be provided. [Work supported by NIH DC00820.]

Relationship between stutterers' genetic history and speech-associated variables

The symptomatology, reading ability, anxiety levels, responsiveness to therapy, and speech-motor behavior of elementary- and high-school children who stutter and had a positive family history of stuttering were compared with those of stutterers with a negative kinship history of stuttering. The stutterers with a positive family history of stuttering differed significantly from those whose family history was negative with respect to the frequency of silent and oral prolongations and speech-motor behavior. These findings suggest that their neuromotor functioning is related to their genetic susceptibility to stuttering.

Three-dimensional representation of articulatory kinematics from x-ray microbeam data

Records of speech-related movements of flesh points and anatomic landmarks obtained from the University of Wisconsin x-ray microbeam system are fundamentally two dimensional in the sense that they provide time histories of relative positions of points within a plane. However, the third spatial dimension associated with each point is implicit in its two-space representation and, under special conditions, can be reconstructed mathematically. For example, three points attached to a rigid body such as the mandible determine a system of three polynomial equations, which, when solved, provides an account of the location of each point with respect to sagittal and coronal plane axes. Both the feasibility and resolution limits of a conventional numerical approach to this problem have been established by analysis of calibrated movements of three-point arrays attached to a machine-driven phantom and tracked by the microbeam system. Moreover, the same analysis procedure has been applied to kinematic data for multipoint arrays attached to the head and mandible of nine adult subjects to determine whether and to what extent their respective movements, during speech and other selected oral motor behaviors, are restricted to the sagittal plane. The advantages of a three-dimensional representation of speech motor behavior for at least these structures, within the context of recent microbeam experiments, will be discussed. [Work supported by NIH Grant NS-16373.]

Speech production and perception in a patient with severe impairment of somesthetic perception and motor control.

Studies were made of speech and other motor behavior of a 17-year-old female with severe chronic difficulties in swallowing, chewing, and speaking. Studies included: (a) physical and neurological examination; (b) phonological analysis; (c) electromyography; (d) cinefluorography; (e) non-speech motor tests; (f) tests of phoneme perception, and (g) dichotic auditory perception tests. Neurological examination revealed severe defects in complex somesthetic sensation (e.g. stereognosis). Other sensory functions, including hearing, were normal. Although motor abnormalities of extrapyramidal, cerebellar or peripheral origin were not indicated, the patient was unable to activate the several muscles required for any given speech gesture while at the same time independently controlling their various patterns of activity in normal fashion. It was concluded that this difficulty was not primarily of motor origin but resulted from congenital inability to obtain somesthetic information necessary for learning of the patterns of spatial distribution and temporal modulation of muscle contraction accompanying normal speech. Despite the severe speech production deficits, speech perception approached normality, even in some characteristics which, according to the motor theory of speech perception, are dependent on the listener’s referring to the neural correlates of normal speech motor control. Reference to normal motor information does not therefore appear necessary for these types of perceptual performance.