Association of Orofacial Muscle Activity and Movement During Changes in Speech Rate and Intensity

2003 ◽  
Vol 46 (6) ◽  
pp. 1387-1400 ◽  
Author(s):  
Michael D. McClean ◽  
Stephen M. Tasko

Understanding how orofacial muscle activity and movement covary across changes in speech rate and intensity has implications for the neural control of speech production and the use of clinical procedures that manipulate speech prosody. The present study involved a correlation analysis relating average lower-lip and jaw-muscle activity to lip and jaw movement distance, speed, and duration. Recordings were obtained on orofacial movement, muscle activity, and the acoustic signal in 3 normal speakers as they repeated a simple test utterance with targeted speech rates varying from 60% to 160% of their habitual rate and at targeted vocal intensities of –6 dB and +6 dB relative to their habitual intensity. Surface electromyographic (EMG) recordings were obtained with electrodes positioned to sample primarily the mentalis, depressor labii inferior, anterior belly of the digastric, and masseter muscles. Two-dimensional displacements of the lower lip and jaw in the midsagittal plane were recorded with an electromagnetic system. All participants produced linear changes in percent utterance duration relative to the auditory targets for speech rate variation. Intensity variations ranged from –10 dB to +8 dB. Average EMG levels for all 4 muscles were well correlated with specific parameters of movement. Across the intensity conditions, EMG level was positively correlated with movement speed and distance in all participants. Across the rate conditions, EMG level was negatively correlated with movement duration in all participants, while greater interparticipant variability was noted for correlations relating EMG to speed and distance. For intensity control, it is suggested that converging neural input to orofacial motoneurons varies monotonically with movement distance and speed. In contrast, rate control appears to be more strongly related to the temporal characteristics of neural input than activation level.

2004 ◽  
Vol 47 (2) ◽  
pp. 294-303 ◽  
Author(s):  
Michael D. McClean ◽  
Stephen M. Tasko ◽  
Charles M. Runyan

This study was intended to replicate and extend previous findings that (a) during fluent speech persons who stutter (PS) and those who do not (NS) differ in their vocal tract closing movements (L. Max, A. J. Caruso, & V. L. Gracco, 2003) and (b) ratios relating lip and tongue speed to jaw speed increase with stuttering severity (M. D. McClean & C. R. Runyan, 2000). An electromagnetic system was used to record movements of the upper lip, lower lip, tongue, and jaw of 43 NS and 37 PS during productions of a nonsense phrase and a sentence. Measurement and analysis of movement speeds, durations, and ratios of lip and tongue speed to jaw speed were performed on fluent productions of a nonsense phrase and sentence. Statistical comparisons were made between PS with low and high stuttering severity levels (LPS and HPS) and NS. Significant variations across groups in movement speed and duration were observed, but the pattern of these effects was complex and did not replicate the results of the two earlier studies. In the nonsense phrase, significant reductions in lower lip closing duration, jaw closing duration, and jaw closing speed were seen in PS. In the sentence task, HPS showed elevated tongue opening and closing durations. For tongue opening in the sentence, LPS showed elevated speeds and HPS showed reduced speeds. The elevated speeds for LPS are interpreted as a contributing factor to speech disfluency, whereas the reduced speeds and increased durations in HPS are attributed to adaptive behavior intended to facilitate fluent speech. Significant group effects were not seen for the speed ratio measures. Results are discussed in relation to multivariate analyses intended to identify subgroups of PS.


1992 ◽  
Vol 67 (6) ◽  
pp. 1417-1427 ◽  
Author(s):  
G. L. Gottlieb ◽  
M. L. Latash ◽  
D. M. Corcos ◽  
T. J. Liubinskas ◽  
G. C. Agarwal

1. Normal human subjects made discrete elbow flexions in the horizontal plane under different task conditions of initial or final position, inertial loading, or instruction about speed. We measured joint angle, acceleration, and electromyographic signals (EMGs) from two agonist and two antagonist muscles. 2. For many of the experimental tasks, the latency of the antagonist EMG burst was strongly correlated with parameters of the first agonist EMG burst defined by a single equation, expressed in terms of the agonist's hypothetical excitation pulse. Latency is proportional to the ratio of pulse duration to pulse intensity, making it proportional to movement distance and inertial load and inversely proportional to planned movement speed. However, these rules are not sufficient to define the timing of every possible single joint movement. 3. For movements described by the speed-insensitive strategy, the quantity of both antagonist and agonist muscle activity can be uniformly associated with selected kinetic measures that incorporate muscle force-velocity relations. 4. For movements collectively described by the speed-sensitive strategy, (i.e., that have direct or indirect constraints on speed), no single rule can describe all the combinations of agonist-antagonist coordination that are used to perform these diverse tasks. 5. Estimates of joint viscosity were made by calculating the amount of velocity-dependent torque used to terminate movements on target. These estimates are similar to those that have previously been made of limb viscosity during postural maintenance. They imply that a significant component of muscle activity must be used to overcome these forces. 6. These and previous results are all consistent with a dual-strategy hypothesis for those single-joint movements that are sufficiently fast to require pulse-like muscle activation patterns. The major features of such patterns (pulse intensities, durations, and latencies) are determined by central commands programmed in advance of movement initiation. The selection between speed-insensitive or speed-sensitive rules of motoneuron pool excitation is implicitly specified by the nature of speed constraints of the movement task.


2000 ◽  
Vol 43 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Michael D. McClean

To understand the clinical aspects of speech rate control, a clearer picture is needed of how orofacial structures are coordinated across variations in speech rate. To address this problem, patterns of orofacial tangential velocity or speed were analyzed in a group of 9 normal speakers as they produced the utterance “a bad daba” at fast, normal, and slow speech rates. An electromagnetic system was used to record the movements of the upper lip, lower lip, jaw, and tongue. Measures of the magnitude of peak tangential velocities were obtained across the four structures. Orofacial velocities consistently decreased at slow rates relative to normal rates, whereas at fast rates increased and decreased velocities were observed in an equivalent number of cases. Significant correlations frequently were obtained across speech rate between lip, tongue, and jaw velocities. Upper and lower lip velocities showed consistent positive correlations with one another, whereas marked intersubject differences were observed in the sign of jaw-related correlations. Repeated testing on 3 subjects indicated a high degree of consistency within subjects in the overall patterns of mean velocity for the different structures. Results are discussed in relation to possible motor control differences underlying fast and slow speech, neural coupling of muscle systems, and jaw-related individual differences in speech motor coordination.


2000 ◽  
Vol 43 (6) ◽  
pp. 1524-1531 ◽  
Author(s):  
Michael D. McClean ◽  
Charles M. Runyan

Stuttering can be characterized in part as a disorder in the coordination of different muscle systems. In light of basic aspects of orofacial physiology and development, the speeds of the lips and tongue relative to the jaw may be an important dimension for evaluating motor coordination among persons who stutter (PWS). To test this idea, an electromagnetic system was used to obtain measures of lip, tongue, and jaw speed in 38 adults (29 PWS and 9 normally fluent speakers, NFS) as they repeated a simple speech utterance at a normal rate. Using categorical ratings of stuttering severity, ratios of tongue speed to jaw speed were significantly greater in PWS rated as severe, compared to NFS and other PWS. Significant increases in lower lip-to-jaw and tongue-to-jaw speed ratios with stuttering severity were also reflected in correlation analyses relating speed ratios to a continuous measure of stuttering severity. These trends in speed ratio were related to increases in lower lip and tongue speed and decreases in jaw speed with stuttering severity. Sources of the speed differences are discussed in relation to underlying muscle activity, motor compensation processes in adults, and the development of orofacial motor control in children who stutter.


1995 ◽  
Vol 32 (5) ◽  
pp. 382-389 ◽  
Author(s):  
Takashi Tachimura ◽  
Hisanaga Hara ◽  
Takeshi Wada

This study was designed to determine if levator veli palatini muscle activity can be elicited by simultaneous changes in oral air pressure and nasal air flow when a speech appliance is in place. The speech appliances routinely worn by 15 subjects were each modified experimentally by drilling a hole in the vertical center of the pharyngeal bulb. The air flow rate into the nasal cavity through the opening in the bulb was altered by changing the circular area of the opening in the bulb from the occluded condition (Condition I), to circular area of 12.6 mm2 (4 mm in diameter; Condition II), and then to 38.5 mm2 (7 mm in diameter; Condition III). Electromyographic activity was measured from the levator veli palatini muscle with changes in nasal air flow rate and oral air pressure. Levator veli palatini muscle activity was correlated with changes in nasal air flow and oral air pressure. Increases in levator veli palatini muscle activity were associated with increases in nasal air flow rate compared to oral air pressure changes. The results indicated that aerodynamic variables of nasal air flow and oral air pressure might be involved in the neural control of speech production in individuals wearing a speech appliance, even if the subjects exhibit velopharyngeal incompetence without using a speech appliance. Also, the stimulating effect of bulb reduction therapy on velopharyngeal function might be achieved through the change in aerodynamic variables in association with the bulb reduction.


2016 ◽  
Vol 115 (6) ◽  
pp. 3238-3248 ◽  
Author(s):  
Adam G. Rouse ◽  
Marc H. Schieber

In reaching to grasp an object, proximal muscles that act on the shoulder and elbow classically have been viewed as transporting the hand to the intended location, while distal muscles that act on the fingers simultaneously shape the hand to grasp the object. Prior studies of electromyographic (EMG) activity in upper extremity muscles therefore have focused, by and large, either on proximal muscle activity during reaching to different locations or on distal muscle activity as the subject grasps various objects. Here, we examined the EMG activity of muscles from the shoulder to the hand, as monkeys reached and grasped in a task that dissociated location and object. We quantified the extent to which variation in the EMG activity of each muscle depended on location, on object, and on their interaction—all as a function of time. Although EMG variation depended on both location and object beginning early in the movement, an early phase of substantial location effects in muscles from proximal to distal was followed by a later phase in which object effects predominated throughout the extremity. Interaction effects remained relatively small. Our findings indicate that neural control of reach-to-grasp may occur largely in two sequential phases: the first, serving to project the entire upper extremity toward the intended location, and the second, acting predominantly to shape the entire extremity for grasping the object.


2006 ◽  
Vol 96 (1) ◽  
pp. 197-208 ◽  
Author(s):  
Birgit Larsen ◽  
Michael Voigt

The main aims of this study were 1) to investigate possible phase-, speed-, and task-dependent changes in the quadriceps H-reflex during pedaling, and to achieve this, 2) to develop an optimized H-reflex recording and processing procedure for recording of quadriceps H-reflexes during movement. It was hypothesized that the behavior of the quadriceps H-reflex concerning phase, speed, and task dependency corresponds to the behavior of the soleus H-reflex during rhythmical leg movements. The applied H-reflex procedure appeared to be reliable for obtaining the quadriceps H-reflex modulation during leg movement. The vastus lateralis (VL) and rectus femoris (RF) H-reflexes showed a phase-dependent modulation during pedaling at a frequency of 80 rpm with almost parallel changes in the reflex amplitude and motor recruitment level. However, when the speed of movement was reduced from 80 to 40 revolutions per minute (rpm) and crank load simultaneously increased (i.e., a halving of the movement speed with a constant motor recruitment level), the quadriceps H-reflex modulation pattern changed significantly in relation to the pattern of motor recruitment, i.e., at 40 rpm, the reflex excitability remained high during a gradual derecruitment during power generation in downstroke. Comparison of the “operationally defined H-reflex gain function” obtained during 1) pedaling at 80 rpm and 2) isometric quadriceps contractions in sitting position showed no significant task-dependent changes in the quadriceps H-reflex. Consequently, the hypothesis was only partly corroborated, and the findings indicate differences in the neural control of the soleus and the quadriceps muscle during rhythmical movements.


2011 ◽  
Vol 320 ◽  
pp. 394-398
Author(s):  
Zhen Kai Zhao ◽  
Yan Pei Song ◽  
Zhi Ming Feng

A model of the movement of WC reinforcing particles with the effect of centrifugal force during the process of centrifugal casting was established. The motion equations of the WC particles were solved in this model. The motion curve of the WC particles WC particle was drawn according to the motion equation, and the influential factors of WC particle's movement are analyzed. The conclusions show that: the radical movement speed of the WC particles increases with the increase of time, and the movement distance increases by exponentially at the same time. The particle movement distance at the same time increases due to the larger diameter, the quicker centrifugal speed and the higher the casting temperature. The radial pitch of the particle with different initial position becomes lager with the increase of time. Centrifugal Casting formed the final particle reinforced composites, in which the volume fraction of WC particles gradient increased from the inner surface to the outer surface.


1978 ◽  
Vol 43 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Billie Daniel ◽  
Barry Guitar

A case report is presented of an attempt to increase muscle activity during non-speech and speech activities through surface electromyographic feedback. The subject, a 25-year-old male, had a surgical anastomosis of the seventh cranial to the twelfth cranial nerve five years prior to the initiation of this therapy. The right side of the face was immobile. Frequency analogs of muscle action potentials from the right lower lip during pressing, retraction, eversion, and speech were presented to the subject. His task was to increase the frequency of the tone thereby increasing muscle activity. The subject made substantial improvement in the gestures listed above. Electrodes also were placed in various infraorbital positions for an upper lip lifting task. This gesture was unimproved. Pre- and posttherapy independence of facial gestures from conscious tongue contraction was found. Possible explanations were proposed for (1) increases of muscle activity in the lower lip, (2) lack of change of MAPs in the upper lip, (3) independence of the facial muscle activity from conscious tongue contraction, and (4) effectiveness of this feedback training.


2021 ◽  
Author(s):  
Lahiru N. Wimalasena ◽  
Jonas F. Braun ◽  
Mohammad Reza Keshtkaran ◽  
David Hofmann ◽  
Juan Álvaro Gallego ◽  
...  

AbstractObjectiveTo study the neural control of movement, it is often necessary to estimate how muscles are activated across a variety of behavioral conditions. However, estimating the latent command signal that underlies muscle activation is challenging due to its complex relation with recorded electromyographic (EMG) signals. Common approaches estimate muscle activation independently for each channel or require manual tuning of model hyperparameters to optimally preserve behaviorally-relevant features.ApproachHere, we adapted AutoLFADS, a large-scale, unsupervised deep learning approach originally designed to de-noise cortical spiking data, to estimate muscle activation from multi-muscle EMG signals. AutoLFADS uses recurrent neural networks (RNNs) to model the spatial and temporal regularities that underlie multi-muscle activation.Main ResultsWe first tested AutoLFADS on muscle activity from the rat hindlimb during locomotion, and found that it dynamically adjusts its frequency response characteristics across different phases of behavior. The model produced single-trial estimates of muscle activation that improved prediction of joint kinematics as compared to low-pass or Bayesian filtering. We also tested the generality of the approach by applying AutoLFADS to monkey forearm muscle activity from an isometric task. AutoLFADS uncovered previously uncharacterized high-frequency oscillations in the EMG that enhanced the correlation with measured force compared to low-pass or Bayesian filtering. The AutoLFADS-inferred estimates of muscle activation were also more closely correlated with simultaneously-recorded motor cortical activity than other tested approaches.SignificanceUltimately, this method leverages both dynamical systems modeling and artificial neural networks to provide estimates of muscle activation for multiple muscles that can be used for further studies of multi-muscle coordination and its control by upstream brain areas.


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