Nonspeech Movements Research Articles

Speaking to a metronome reduces kinematic variability in typical speakers and people who stutter.

Several studies indicate that people who stutter show greater variability in speech movements than people who do not stutter, even when the speech produced is perceptibly fluent. Speaking to the beat of a metronome reliably increases fluency in people who stutter, regardless of the severity of stuttering. Here, we aimed to test whether metronome-timed speech reduces articulatory variability. We analysed vocal tract MRI data from 24 people who stutter and 16 controls. Participants repeated sentences with and without a metronome. Midsagittal images of the vocal tract from lips to larynx were reconstructed at 33.3 frames per second. Any utterances containing dysfluencies or non-speech movements (e.g. swallowing) were excluded. For each participant, we measured the variability of movements (coefficient of variation) from the alveolar, palatal and velar regions of the vocal tract. People who stutter had more variability than control speakers when speaking without a metronome, which was then reduced to the same level as controls when speaking with the metronome. The velar region contained more variability than the alveolar and palatal regions, which were similar. These results demonstrate that kinematic variability during perceptibly fluent speech is increased in people who stutter compared with controls when repeating naturalistic sentences without any alteration or disruption to the speech. This extends our previous findings of greater variability in the movements of people who stutter when producing perceptibly fluent nonwords compared with controls. These results also show, that in addition to increasing fluency in people who stutter, metronome-timed speech also reduces articulatory variability to the same level as that seen in control speakers.

Identifying and Treating Functional “Nonnative [Foreign] Accent Syndrome”: Perspectives From the Patient and Speech-Language Pathologist

Purpose: When nonnative speaking patterns emerge following neurologic insult or injury, it has often been referred to as foreign, or nonnative, accent syndrome (FAS). In many other cases, FAS can occur as a manifestation of a functional speech disorder (FSD). The purpose of this clinical focus article is to (a) describe the methods utilized in identifying and managing a functional communication disorder characterized by nonnative speech, language, and nonverbal communication intrusions, accompanied by a functional movement disorder and (b) describe the patient's lived experience. Method and Results: The patient is a 59-year-old monolingual English-speaking gentleman with a remote history of episodic stuttering, who later developed an abrupt onset of a nonnative speaking style that changed in quality over time. He also developed gait difficulties that, after visiting with several neurologists, were judged to reflect a functional neurological disorder. During the speech evaluation session, an “Eastern European accent” was noted, along with nonnative word use and word order. A diagnosis of FSD characterized by foreign accent was made, and intervention was undertaken as detailed in the clinical focus article and demonstrated in the accompanying video. With behavioral intervention, the patient was able to correct sound-level changes in structured tasks such as reading and repetition and then in conversation. Language dialect–like changes resolved without direct intervention. The nonspeech movement disorder was addressed with intensive occupational and physical therapy. Conclusions: The patient presented with functional FAS, which was effectively managed with symptomatic, targeted behavioral intervention. His experience demonstrates the importance of patient advocacy in acquiring an accurate diagnosis and appropriate management recommendations. Supplemental Material: https://doi.org/10.23641/asha.24653430

The effect of motor resource suppression on speech perception in noise in younger and older listeners: An online study.

Speech motor resources may be recruited to assist challenging speech perception in younger normally hearing listeners, but the extent to which this occurs for older adult listeners is unclear. We investigated if speech motor resources are also recruited in older adults during speech perception. Specifically, we investigated if suppression of speech motor resources via sub-vocal rehearsal affects speech perception compared to non-speech motor suppression (jaw movement) and passive listening. Participants identified words in speech-shaped noise at signal-to-noise ratios (SNRs) from -16 to +16 dB in three listening conditions during which participants: (1) opened and closed their jaw (non-speech movement); (2) sub-vocally mimed 'the' (articulatory suppression); (3) produced no concurrent movement (passive listening). Data from 46 younger adults (M age = 20.17 years, SD = 1.61, 36 female) and 41 older adults (M age = 69 years, SD = 5.82, 21 female) were analysed. Linear mixed effects modelling investigated the impact of age, listening condition, and self-reported hearing ability on speech perception (d' prime). Results indicated that speech perception ability was significantly worse in older adults relative to younger adults across all listening conditions. A significant interaction between age group and listening condition indicated that younger adults showed poorer performance during articulatory suppression compared to passive listening, but older adults performed equivalently across conditions. This finding suggests that speech motor resources are less available to support speech perception in older adults, providing important insights for auditory-motor integration for speech understanding and communication in ageing.

A store-and-forward cloud-based telemonitoring system for automatic assessing dysarthria evolution in neurological diseases from video-recording analysis

Background and objectives:Patients suffering from neurological diseases may develop dysarthria, a motor speech disorder affecting the execution of speech. Close and quantitative monitoring of dysarthria evolution is crucial for enabling clinicians to promptly implement patients’ management strategies and maximizing effectiveness and efficiency of communication functions in term of restoring, compensating or adjusting. In the clinical assessment of orofacial structures and functions, at rest condition or during speech and non-speech movements, a qualitative evaluation is usually performed, throughout visual observation. Methods:To overcome limitations posed by qualitative assessments, this work presents a store-and-forward self-service telemonitoring system that integrates, within its cloud architecture, a convolutional neural network (CNN) for analyzing video recordings acquired by individuals with dysarthria. This architecture – called facial landmark Mask RCNN – aims at locating facial landmarks as a prior for assessing the orofacial functions related to speech and examining dysarthria evolution in neurological diseases. Results:When tested on the Toronto NeuroFace dataset, a publicly available annotated dataset of video recordings from patients with amyotrophic lateral sclerosis (ALS) and stroke, the proposed CNN achieved a normalized mean error equal to 1.79 on localizing the facial landmarks. We also tested our system in a real-life scenario on 11 bulbar-onset ALS subjects, obtaining promising outcomes in terms of facial landmark position estimation. Discussion and conclusions:This preliminary study represents a relevant step towards the use of remote tools to support clinicians in monitoring the evolution of dysarthria.

Distinguishing Spastic and Dystonic Features in a Patient With a History of Brainstem Encephalitis: A Clinical Case Study

Purpose One role of a speech-language pathologist (SLP) is to differentially diagnose motor speech disorders to aid physicians, typically neurologists, in establishing a medical diagnosis. The present case study describes the clinical problem solving undertaken by the SLP to characterize the nature of neurological deficits to develop an appropriate management plan. Method The patient is a 29-year-old man with a history of brainstem encephalitis who presented for evaluation of dysarthria, dysphagia, and gait difficulties. The neurological exam characterized a spastic dysarthria. The SLP conducted a motor speech examination expressly for the purpose of differential diagnosis. Results The patient exhibited features of spastic dysarthria including strained phonation and hypernasality, equivocally slow rate associated with intermittent interword pauses rather than lengthened segments, and articulatory imprecision in the absence of weakness or slowness of the articulators. Defining features of spastic dysarthria absent from his speech were monopitch and monoloudness, as well as slow alternate motion rates. A diagnosis of hyperkinetic dysarthria associated with dystonia was informed by (a) hypernasality disproportionate to other deviant speech features, with preserved reflexive velar movements and nonspeech movements; (b) adventitious lip pursing; (c) modest improvement in speech with sensory tricks; (d) mild and intermittent phonatory strain; and (e) normal nonspeech oral motor function. Conclusions This case demonstrates the role speech-language pathology can play in the neurological assessment and management process. The recognition by the SLP of hyperkinetic dysarthria led to additional diagnostic tests and to a broader range of options for medical management.

Dissociated Development of Speech and Limb Sensorimotor Learning in Stuttering: Speech Auditory-motor Learning is Impaired in Both Children and Adults Who Stutter

Stuttering is a neurodevelopmental disorder of speech fluency. Various experimental paradigms have demonstrated that affected individuals show limitations in sensorimotor control and learning. However, controversy exists regarding two core aspects of this perspective. First, it has been claimed that sensorimotor learning limitations are detectable only in adults who stutter (after years of coping with the disorder) but not during childhood close to the onset of stuttering. Second, it remains unclear whether stuttering individuals’ sensorimotor learning limitations affect only speech movements or also unrelated effector systems involved in nonspeech movements. We report data from separate experiments investigating speech auditory-motor learning (N = 60) and limb visuomotor learning (N = 84) in both children and adults who stutter versus matched nonstuttering individuals. Both children and adults who stutter showed statistically significant limitations in speech auditory-motor adaptation with formant-shifted feedback. This limitation was more profound in children than in adults and in younger children versus older children. Between-group differences in the adaptation of reach movements performed with rotated visual feedback were subtle but statistically significant for adults. In children, even the nonstuttering groups showed limited visuomotor adaptation just like their stuttering peers. We conclude that sensorimotor learning is impaired in individuals who stutter, and that the ability for speech auditory-motor learning—which was already adult-like in 3–6 year-old typically developing children—is severely compromised in young children near the onset of stuttering. Thus, motor learning limitations may play an important role in the fundamental mechanisms contributing to the onset of this speech disorder.

Neural dynamics of speech and non-speech motor planning

As the speech apparatus is also involved in producing non-speech movements, understanding whether speech and non-speech planning are controlled by the same brain mechanisms is central to the comprehension of motor speech planning. A crucial issue is whether a specialized motor planning/control system is dedicated to speech or if the motor planning/control system is shared across oromotor behaviors. We investigated the EEG/ERP spatio-temporal dynamics of the motor planning processes preceding articulation by comparing the production of non-speech gestures matched to monosyllabic words and non-words. To isolate motor from pre-motor planning, we used a delayed production task combined with an articulatory suppression task. Results suggest that the planning processes preceding articulation for non-speech, words and non-words recruit the same neural networks but with different involvement for non-speech and speech. The results support the idea of shared motor planning/control systems for speech and non-speech but with different dynamics for each oromotor behavior.

Does Truth Have a Future?

Does Truth Have a Future?

Impact of Bilingualism on Infants’ Ability to Learn From Talking and Nontalking Faces

AbstractTo probably overcome the challenge of learning two languages at the same time, infants raised in a bilingual environment pay more attention to the mouth of talking faces than same‐age monolinguals. Here we examined the consequences of such preference for monolingual and bilingual infants’ ability to perceive nonspeech information coming from the eyes or the mouth region of talking faces. Using a learning procedure, we recorded 15‐month‐olds’ and 18‐month‐olds’ gaze while watching, at each trial, a speaker producing a sentence systematically followed by a nonspeech movement (eyebrow raise vs. lip protrusion). Differences were obtained for infants in the eyebrow‐raise condition. While 15‐month‐old monolinguals and 18‐month‐old bilinguals learned to anticipate the eyebrow‐raise movement before its appearance, 15‐month‐old bilinguals did not (i.e., they continued to look at the mouth region). Thus, bilingualism appears to impact not only how infants explore talking faces but also how they learn from them.

The motor learning approach and strategies in the treatment of children’s articulation disorders

The article presents a theoretical analysis of the concept based on a motor learning approach as well as the possibilities for the application of this approach in speech and language therapy in the treatment of children’s articulation disorders. Motor learning principles have been emphasised as essential elements in speech and language therapy. They explain the importance of speech and language therapy services which are flexible and focused on individual cases. 
 An analysis of theoretical sources focuses on the strategies of speech and language therapy based on the motor learning approach. These therapies differ between non-speech or speech levels. The aims of the application of these strategies and their theoretical presumptions of efficacy reveals the need for changes in the practice of speech and language therapists. An analysis of theoretical sources reveals that speech-based strategies of therapy are more efficient in learning correct sound pronunciation and promoting the intelligible speech of children. The application of non-speech oral motor therapy is purposeful in teaching non-speech movements of the articulatory system. When coping with children’s articulation disorders, it is necessary to differentiate strategies of motor learning with regard to the origin and level of a particular disorder.

Functional Characterization of the Human Speech Articulation Network

A number of brain regions have been implicated in articulation, but their precise computations remain debated. Using functional magnetic resonance imaging, we examine the degree of functional specificity of articulation-responsive brain regions to constrain hypotheses about their contributions to speech production. We find that articulation-responsive regions (1) are sensitive to articulatory complexity, but (2) are largely nonoverlapping with nearby domain-general regions that support diverse goal-directed behaviors. Furthermore, premotor articulation regions show selectivity for speech production over some related tasks (respiration control), but not others (nonspeech oral-motor [NSO] movements). This overlap between speech and nonspeech movements concords with electrocorticographic evidencethat these regions encode articulators and their states, and with patient evidence whereby articulatory deficits are often accompanied by oral-motor deficits. In contrast, the superior temporal regions show strong selectivity for articulation relative to nonspeech movements, suggesting that these regions play a specific role in speech planning/production. Finally, articulation-responsive portions of posterior inferior frontal gyrus show some selectivity for articulation, in line with the hypothesis that this region prepares an articulatory code that is passed to the premotor cortex. Taken together, these results inform the architecture of the human articulation system.

Afferent and Efferent Aspects of Mandibular Sensorimotor Control in Adults Who Stutter

Individuals who stutter show sensorimotor deficiencies in speech and nonspeech movements. For the mandibular system, the authors dissociated the sense of kinesthesia from the efferent control component to examine whether kinesthetic integrity itself is compromised in stuttering or whether deficiencies occur only when generating motor commands. The authors investigated 11 stuttering and 11 nonstuttering adults' kinesthetic sensitivity threshold and kinesthetic accuracy for passive jaw movements as well as their minimal displacement threshold and positioning accuracy for active jaw movements. They also investigated the correlation with an anatomical index of jaw size. The groups showed no statistically significant differences on sensory measures for passive jaw movements. Although some stuttering individuals performed more poorly than any nonstuttering participants on the active movement tasks, between-group differences for active movements were not statistically significant. Unlike fluent speakers, however, the stuttering group showed a statistically significant correlation between mandibular size and performance in the active and passive near-threshold tasks. Previously reported minimal-movement differences were not replicated. Instead, stuttering individuals' performance varied with anatomical properties. These correlational results are consistent with the hypothesis that stuttering participants generate and perceive movements on the basis of less accurate internal models of the involved neuromechanical systems.

Focus of attention and speech motor performance

PurposeThe aim of the present study was to examine the effect of an internal vs. external ‘focus of attention’ on speech motor performance in healthy young adults. MethodTwenty adults (aged 18–25) participated in a within-subjects experimental design. Nonwords, real words, and tongue twisters were produced by each participant in both attentional focus conditions (internal and external), with order of condition counterbalanced across participants. Speech motor coordinative consistency, timing, and behavioral accuracy were investigated. ResultsAccuracy of nonword, real word and tongue twister productions were relatively high across both external and internal focus conditions. A robust effect of condition on timing measures was noticed such that an internal focus (on articulatory movement) resulted in longer production durations and higher durational variability for most productions. In addition, an internal focus caused an increase in movement coordination variability for the production of real words. ConclusionOur findings offer some preliminary support to the theory that operating in an external ‘focus of attention’ condition, with a focus on acoustic goals, results in more efficient, automatic control of speech movements.Learning outcomes: After reading this article, the reader will be able to: (1) describe the relevance of and challenges associated with the application of principles that govern nonspeech movements to speech performance; (2) summarize the implications of an external vs. internal focus of attention for speech motor performance; and (3) describe its role in speech motor skill learning in healthy and disordered groups.

The effects of word length, articulation, oral-motor movement, and lexicality on gait: A pilot study

Previous research has suggested that articulatory demands are important predictors of the impact of dual-task interference on spatial-temporal parameters of gait. In this study, we evaluated the effects of word length, oral-motor movement, articulation, and lexicality, within a verbal task, on a continuous gait task. Fifteen healthy young women participated in a study in which two word lengths (monosyllabic and bisyllabic) were crossed with four levels of secondary task complexity (no dual-task, non-speech movement, spoken non-word, and spoken word). Spatial and temporal parameters of gait were measured using a 23′ instrumented carpet. Results indicated a significant multivariate main effect for task type, F(15, 120)=3.07, that explained 71.1% of the demonstrated variability in gait. Univariate analyses of this main effect revealed statistically significant effects for velocity, step time, swing time, and stance time, but no statistically significant effect for step length. Post hoc analyses suggested that dual-task interference produced significant changes in the parameters of gait, but that this interference was not significantly greater with non-words as compared to the non-speech movement condition, nor was it significantly greater with words as compared to non-words. The results of this systematic deconstruction of a simple verbal task suggest that the motor component of a secondary speech task may produce the largest amount of interference within a dual-task interference paradigm.

Right-shift for non-speech motor processing in adults who stutter

Introduction In adults who do not stutter (AWNS), the control of hand movement timing is assumed to be lateralized to the left dorsolateral premotor cortex (PMd). In adults who stutter (AWS), the network of speech motor control is abnormally shifted to the right hemisphere. Motor impairments in AWS are not restricted to speech, but extend to non-speech orofacial and finger movements. We here investigated the lateralization of finger movement timing control in AWS. Methods We explored PMd function in 14 right-handed AWS and 15 age matched AWNS. In separate sessions, they received subthreshold repetitive transcranial magnetic stimulation (rTMS) for 20 min at 1 Hz over the left or right PMd, respectively. Pre- and post-stimulation participants were instructed to synchronize their index finger taps of either hand with an isochronous sequence of clicks presented binaurally via earphones. Synchronization accuracy was measured to quantify the effect of the PMd stimulation. Results In AWNS inhibition of left PMd affected synchronization accuracy of the left hand. Conversely, in AWS TMS over the right PMd increased the asynchrony of the left hand. Conclusions The present data indicate an altered functional connectivity in AWS in which the right PMd seems to be important for the control of timed non-speech movements. Moreover, the laterality-shift suggests a compensatory role of the right PMd to successfully perform paced finger tapping.

Speech and oral motor profile after childhood hemispherectomy

Hemispherectomy (disconnection or removal of an entire cerebral hemisphere) is a rare surgical procedure used for the relief of drug-resistant epilepsy in children. After hemispherectomy, contralateral hemiplegia persists whereas gross expressive and receptive language functions can be remarkably spared. Motor speech deficits have rarely been examined systematically, thus limiting the accuracy of postoperative prognosis. We describe the speech profiles of hemispherectomized participants characterizing their intelligibility, articulation, phonological speech errors, dysarthric features, and execution and sequencing of orofacial speech and non-speech movements. Thirteen participants who had undergone hemispherectomy (six left, seven right; nine with congenital, four with acquired hemiplegia; operated between four months and 13 years) were investigated. Results showed that all participants were intelligible but showed a mild dysarthric profile characterized by neuromuscular asymmetry and reduced quality and coordination of movements, features that are characteristic of adult-onset unilateral upper motor neuron dysarthria, flaccid-ataxic variant. In addition, one left and four right hemispherectomy cases presented with impaired production of speech and non-speech sequences. No participant showed evidence of verbal or oral dyspraxia. It is concluded that mild dysarthria is persistent after left or right hemispherectomy, irrespective of age at onset of hemiplegia. These results indicate incomplete functional re-organization for the control of fine speech motor movements throughout childhood, and provide no evidence of hemispheric differences.

Impedance Control and Its Relation to Precision in Orofacial Movement

Speech production involves some of the most precise and finely timed patterns of human movement. Here, in the context of jaw movement in speech, we show that spatial precision in speech production is systematically associated with the regulation of impedance and in particular, with jaw stiffness--a measure of resistance to displacement. We estimated stiffness and also variability during movement using a robotic device to apply brief force pulses to the jaw. Estimates of stiffness were obtained using the perturbed position and force trajectory and an estimate of what the trajectory would be in the absence of load. We estimated this "reference trajectory" using a new technique based on Fourier analysis. A moving-average (MA) procedure was used to estimate stiffness by modeling restoring force as the moving average of previous jaw displacements. The stiffness matrix was obtained from the steady state of the MA model. We applied this technique to data from 31 subjects whose jaw movements were perturbed during speech utterances and kinematically matched nonspeech movements. We observed systematic differences in stiffness over the course of jaw-lowering and jaw-raising movements that were correlated with measures of kinematic variability. Jaw stiffness was high and variability was low early and late in the movement when the jaw was elevated. Stiffness was low and variability was high in the middle of movement when the jaw was lowered. Similar patterns were observed for speech and nonspeech conditions. The systematic relationship between stiffness and variability points to the idea that stiffness regulation is integral to the control of orofacial movement variability.

Establishing a Basic Speech Repertoire without Using NSOME: Means, Motive, and Opportunity

Children who are performing at a prelinguistic level of vocal communication present unique issues related to successful intervention relative to the general population of children with speech disorders. These children do not consistently use meaning-based vocalizations to communicate with those around them. General goals for this group of children include stimulating more mature vocalization types and connecting these vocalizations to meanings that can be used to communicate consistently with persons in their environment. We propose a means, motive, and opportunity conceptual framework for assessing and intervening with these children. This framework is centered on stimulation of meaningful vocalizations for functional communication. It is based on a broad body of literature describing the nature of early language development. In contrast, nonspeech oral motor exercise (NSOME) protocols require decontextualized practice of repetitive nonspeech movements that are not related to functional communication with respect to means, motive, or opportunity for communicating. Successful intervention with NSOME activities requires adoption of the concept that the child, operating at a prelinguistic communication level, will generalize from repetitive nonspeech movements that are not intended to communicate with anyone to speech-based movements that will be intelligible enough to allow responsiveness to the child's wants and needs from people in the environment. No evidence from the research literature on the course of speech and language acquisition suggests that this conceptualization is valid.

Broca's area is crucial for visual discrimination of speech but not nonspeech oral movements

Broca’s area (BA) is crucial for normal speech production, but its role in speech comprehension remains controversial. We used repetitive Transcranial Magnetic Stimulation (rTMS) to reveal that briefly disrupting BA impairs discrimination of visual speech oral movements, but not visual non-speech oral movements. This provides direct evidence that BA is useful in the perception of visual speech information. We demonstrate that the region of the brain responsible for producing speech has a role in the visual perception of speech information, and importantly is not involved in the visual perception of oral movements (gurning) unrelated to speech. Because disrupted performance was observed for speech movements and not nonspeech movements, our data suggests that this form of perception does not benefit from an amodal mirror neuron system general enough to be recruited in the processing of common mouth movements irrespective of their relation to speech. We propose that BA is recruited in the perception of speech because of its role in producing speech.

Motor speech perception modulates the cortical language areas

Traditionally, the left frontal and parietal lobes have been associated with language production while regions in the temporal lobe are seen as crucial for language comprehension. However, recent evidence suggests that the classical language areas constitute an integrated network where each area plays a crucial role both in speech production and perception. We used functional MRI to examine whether observing speech motor movements (without auditory speech) relative to non-speech motor movements preferentially activates the cortical speech areas. Furthermore, we tested whether the activation in these regions was modulated by task difficulty. This dissociates between areas that are actively involved with speech perception from regions that show an obligatory activation in response to speech movements (e.g. areas that automatically activate in preparation for a motoric response). Specifically, we hypothesized that regions involved with decoding oral speech would show increasing activation with increasing difficulty. We found that speech movements preferentially activate the frontal and temporal language areas. In contrast, non-speech movements preferentially activate the parietal region. Degraded speech stimuli increased both frontal and parietal lobe activity but did not differentially excite the temporal region. These findings suggest that the frontal language area plays a role in visual speech perception and highlight the differential roles of the classical speech and language areas in processing others' motor speech movements.