Surface electromyography for speech and swallowing systems: measurement, analysis, and interpretation

Lower nonword syllable sequence repetition accuracy in adults who stutter is related to differences in audio-motor oscillations

OBJECTIVE

The goal of this study was to use independent component analysis (ICA) of high-density electroencephalography (EEG) to investigate whether differences in audio-motor neural oscillations are related to nonword syllable repetition accuracy in a group of adults who stutter compared to typically fluent speakers.

METHODS

EEG was recorded using 128 channels from 23 typically fluent speakers and 23 adults who stutter matched for age, sex, and handedness. EEG was recorded during delayed, 2 and 4 bilabial nonword syllable repetition conditions. Scalp-topography, dipole source estimates, and power spectral density (PSD) were computed for each independent component (IC) and used to cluster similar ICs across participants. Event-related spectral perturbations (ERSPs) were computed for each IC cluster to examine changes over time in the repetition conditions and to examine how dynamic changes in ERSPs are related to syllable repetition accuracy.

RESULTS

Findings indicated significantly lower accuracy on a measure of percentage correct trials in the AWS group and for a normalized measure of syllable load performance across conditions. Analysis of ERSPs revealed significantly lower alpha/beta ERD in left and right μ ICs and in left and right posterior temporal lobe α ICs in AWS compared to TFS (CC p < 0.05). Pearson correlations with %CT for frequency across time showed strong relationships with accuracy (FWE<0.05) during maintenance in the TFS group and during execution in the AWS group.

CONCLUSIONS

Findings implicate lower alpha/beta ERD (8-30 Hz) during syllable encoding over posterior temporal ICs and execution in left temporal/sensorimotor components. Strong correlations with accuracy and interindividual differences in ∼6-8 Hz ERSPs during execution implicate differences in motor and auditory-sensory monitoring during syllable sequence execution in AWS.

A multimodal approach to automated hierarchical assessment of bulbar involvement in amyotrophic lateral sclerosis

Introduction

As a hallmark feature of amyotrophic lateral sclerosis (ALS), bulbar involvement leads to progressive declines of speech and swallowing functions, significantly impacting social, emotional, and physical health, and quality of life. Standard clinical tools for bulbar assessment focus primarily on clinical symptoms and functional outcomes. However, ALS is known to have a long, clinically silent prodromal stage characterized by complex subclinical changes at various levels of the bulbar motor system. These changes accumulate over time and eventually culminate in clinical symptoms and functional declines. Detection of these subclinical changes is critical, both for mechanistic understanding of bulbar neuromuscular pathology and for optimal clinical management of bulbar dysfunction in ALS. To this end, we developed a novel multimodal measurement tool based on two clinically readily available, noninvasive instruments-facial surface electromyography (sEMG) and acoustic techniques-to hierarchically assess seven constructs of bulbar/speech motor control at the neuromuscular and acoustic levels. These constructs, including prosody, pause, functional connectivity, amplitude, rhythm, complexity, and regularity, are both mechanically and clinically relevant to bulbar involvement.

Methods

Using a custom-developed, fully automated data analytic algorithm, a variety of features were extracted from the sEMG and acoustic recordings of a speech task performed by 13 individuals with ALS and 10 neurologically healthy controls. These features were then factorized into 10 composite outcome measures using confirmatory factor analysis. Statistical and machine learning techniques were applied to these composite outcome measures to evaluate their reliability (internal consistency), validity (concurrent and construct), and efficacy for early detection and progress monitoring of bulbar involvement in ALS.

Results

The composite outcome measures were demonstrated to (1) be internally consistent and structurally valid in measuring the targeted constructs; (2) hold concurrent validity with the existing clinical and functional criteria for bulbar assessment; and (3) outperform the outcome measures obtained from each constituent modality in differentiating individuals with ALS from healthy controls. Moreover, the composite outcome measures combined demonstrated high efficacy for detecting subclinical changes in the targeted constructs, both during the prodromal stage and during the transition from prodromal to symptomatic stages.

Discussion

The findings provided compelling initial evidence for the utility of the multimodal measurement tool for improving early detection and progress monitoring of bulbar involvement in ALS, which have important implications in facilitating timely access to and delivery of optimal clinical care of bulbar dysfunction.

Extrinsic Laryngeal Muscle Activity With Different Diameters and Water Depths in a Semi-Occluded Vocal Tract Exercise

PURPOSE

Surface electromyography (sEMG) has been used to evaluate extrinsic laryngeal muscle activity during swallowing and phonation. In the current study, sEMG amplitudes were measured from the infrahyoid and suprahyoid muscles during phonation through a tube submerged in water.

METHOD

The sEMG amplitude values measured from the extrinsic laryngeal muscles and the electroglottographic contact quotient (CQ) were obtained simultaneously from 62 healthy participants (31 men, 31 women) during phonation through a tube at six different depths (2, 4, 7, 10, 15, and 20 cm) while using two tubes with different diameters (1 and 0.5 cm).

RESULTS

With increasing depth, the sEMG amplitude for the suprahyoid muscles increased in men and women. However, sEMG amplitudes for the infrahyoid muscles increased significantly only in men. Tube diameter had a significant effect on the suprahyoid sEMG amplitudes only for men, with higher sEMG amplitudes when phonating with a 1.0-cm tube. CQ values increased with submerged depth for both men and women. Tube diameter affected results such than CQ values were higher for men when using the wider tube and for women with the narrower tube.

CONCLUSIONS

Vocal fold vibratory patterns changed with the depth of tube submersion in water for both men and women, but the patterns of muscle activation differed between the sexes. This suggests that men and women use different strategies when confronted with increased intraoral pressure during semi-occluded vocal tract exercises. In this study, sEMG provided insight into the mechanism for differences between vocally normal individuals and could help detect compensatory muscle activation during tube phonation in water for people with voice disorders.

Is Surface Electromyography (sEMG) a Useful Tool in Identifying Muscle Tension Dysphonia? An Integrative Review of the Current Evidence

OBJECTIVE

This integrative review aims to determine the quality level of evidence on using surface electromyography (sEMG) as a diagnostic tool in identifying muscle tension dysphonia.

METHOD

Two independent reviewers used one search engine and five databases to identify sEMG studies published between January 1980 and December 2020, using a set of specified search terms related to muscle tension dysphonia. The selected articles were systematically evaluated by two independent raters using a modified critical appraisal of diagnostic evidence (m-CADE) form.

RESULTS

Nine articles that satisfied the inclusion criteria were selected from among 576 studies for evaluation. These nine studies showed varied methodological approaches in sEMG measurements, including electrode configuration and position, tasks used in sEMG data collection, outcome measure, and normalization procedures. Five studies showed relatively high m-CADE scores, which were indicative of "suggestive validity and compelling importance". Two studies were rated as "suggestive validity and importance", while two remaining studies were rated as "less suggestive or equivocal validity and importance".

CONCLUSIONS

The review found a moderate level of evidence that sEMG can be a potentially useful tool with diagnostic value in identifying muscle tension dysphonia. However, evidence is not yet available to determine the diagnostic accuracy of sEMG for muscle tension dysphonia. More studies are needed, and it is recommended that future studies involving sEMG and reference measurements should be undertaken using a blinding procedure in order to control any subjective biases. Details of the population that the sEMG has been tested on should be outlined clearly so that spectrum bias could be eliminated or minimized in the application process. Furthermore, it is suggested that a reliable and valid protocol in collecting sEMG data during speech should be developed to minimize the variability of sEMG measures in assessing muscle activities during speech.

Predicting Dysphonia by Measuring Surface Electromyographic Activity of the Supralaryngeal Muscles

PURPOSE

This study set out to investigate whether individuals with dysphonia, as determined by either self-assessment or clinician-based auditory-perceptual judgment, exhibited differences in perilaryngeal muscle activities using surface electromyography (sEMG) during various phonatory tasks. Additionally, the study aimed to assess the effectiveness of sEMG in identifying dysphonic cases.

METHOD

A total of 77 adults (44 women, 33 men, Mage = 30.4 years) participated in this study, with dysphonic cases identified separately using either a 10-item Voice Handicap Index (VHI-10) or clinician-based auditory-perceptual voice quality (APVQ) evaluation. sEMG activities were measured from the areas of suprahyoid and sternocleidomastoid muscles during prolonged vowel /i/ phonations at different pitch and loudness levels. Normalized root-mean-square value against the maximal voluntary contraction (RMS %MVC) of the sEMG signals was obtained for each phonation and compared between subject groups and across phonatory tasks. Additionally, binary logistic regression analysis was performed to determine how the sEMG measures could predict the VHI-10-based or APVQ-based dysphonic cases.

RESULTS

Participants who scored above the criteria on either the VHI-10 (n = 29) or APVQ judgment (n = 17) exhibited significantly higher RMS %MVC in the right suprahyoid muscles compared to the corresponding control groups. Although the RMS %MVC value from the right suprahyoid muscles alone was not a significant predictor of self-evaluated dysphonic cases, a combination of the RMS %MVC values from both the right and left suprahyoid muscles significantly predicted APVQ-based dysphonic cases with a 69.66% fair level.

CONCLUSIONS

This study found that individuals with dysphonia, as determined by either self-assessment or APVQ judgment, displayed more imbalanced suprahyoid muscle activities in voice production compared to nondysphonic groups. The combination of the sEMG measures from both left and right suprahyoid muscles showed potential as a predictor of dysphonia with a fair level of confidence.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25112804.

Comparison of Laryngeal Palpatory Scale (LPS), With Surface Electromyographic Measures in Patients with Muscle Tension Dysphonia

OBJECTIVES

The aim of this study was to examine the laryngeal palpatory scale (LPS) to ascertain possible correlation with neck surface electromyography (sEMG).

METHODS

Two otolaryngologists and one certified speech-language pathologist assessed 21 participants (seven women and 14 men; with a mean age of 42.8 years; ranged: 21 to 70 years) with muscle tension dysphonia (MTD) diagnosed with the current version of the LPS rating system. Consequently, relationships between LPS and objective measures of sEMG were evaluated using Spearman's rank correlation coefficient (r).

RESULTS

The results show that there was a low to moderate between correlations, (statistically positive and significant in 10 correlations among the examined items/states).

CONCLUSIONS

In conclusion, low-moderate positive correlations between sEMG and LPS ratings were found with particular strength for LPS ratings of tightness and ratings made during dynamic tasks. Further investigations can provide useful evidence for researchers and clinicians to document treatment outcomes by using LPS and sEMG in patients with MTD and leading to the more standardized care and improved information about patient progress.

Neuromuscular adaptations of swallowing and speech in unilateral cerebral palsy: shared and distinctive traits

Our aims were to 1) examine the neuromuscular control of swallowing and speech in children with unilateral cerebral palsy (UCP) compared with typically developing children (TDC), 2) determine shared and separate neuromuscular underpinnings of the two functions, and 3) explore the relationship between this control and behavioral outcomes in UCP. Surface electromyography (sEMG) was used to record muscle activity from the submental and superior and inferior orbicularis oris muscles during standardized swallowing and speech tasks. The variables examined were normalized mean amplitude, time to peak amplitude, and bilateral synchrony. Swallowing and speech were evaluated using standard clinical measures. Sixteen children with UCP and 16 TDC participated (7-12 yr). Children with UCP demonstrated higher normalized mean amplitude and longer time to peak amplitude across tasks than TDC (P < 0.01; and P < 0.02) and decreased bilateral synchrony than TDC for swallows (P < 0.01). Both shared and distinctive neuromuscular patterns were observed between swallowing and speech. In UCP, higher upper lip amplitude during swallows was associated with shorter normalized mealtime durations, whereas higher submental bilateral synchrony was related to longer mealtime durations. Children with UCP demonstrate neuromuscular adaptations for swallowing and speech, which should be further evaluated for potential treatment targets. Furthermore, both shared and distinctive neuromuscular underpinnings between the two functions are documented.NEW & NOTEWORTHY Systematically studying the swallowing and speech of children with UCP is new and noteworthy. We found that they demonstrate neuromuscular adaptations for swallowing and speech compared with typically developing peers. We examined swallowing and speech using carefully designed tasks, similar in motor complexity, which allowed us to directly compare patterns. We found shared and distinctive neuromuscular patterns between swallowing and speech.

High-Density Surface Electromyography for Swallowing Evaluation in Post-Radiation Dysphagia

OBJECTIVES

Our study aimed to investigate the feasibility of using high-density surface electromyography (HD-sEMG) for swallowing assessment by comparing the quantitative parameters and topographic patterns of HD-sEMG between post-irradiated patients and healthy individuals.

METHODS

Ten healthy volunteers and ten post-irradiated nasopharyngeal carcinoma patients were recruited. 96-channel HD-sEMG was recorded although each participant consumed different consistencies of food (thin and thick liquid, puree, congee, and soft rice). Dynamic topography was generated from the root mean square (RMS) of the HD-sEMG signals to illustrate the anterior neck muscle function in the swallowing process. The averaged power of muscles and the symmetry of swallowing patterns were assessed by objective parameters including average RMS, Left/Right Energy Ratio, and Left/Right Energy Difference.

RESULTS

The study showed different swallowing patterns between patients with dysphagia and healthy individuals. The mean RMS values were higher in the patient group compared to the healthy group, but the difference was not statistically significant. Asymmetrical patterns were shown in patients with dysphagia.

CONCLUSION

HD-sEMG is a promising technique that could be used to quantitatively evaluate the average power of neck muscles and the symmetry of swallowing activities in patients with swallowing difficulties.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 133:2920-2928, 2023.

Effects of Age and Lingual-Palatal Pressure Levels on Submental Surface Electromyography Measures

Submental surface electromyography (sEMG) may provide information about the lingual-palatal pressure (LPP) during swallowing. However, the extent to which changes in age and LPP levels are reflected in different sEMG measures is unclear. This study aimed to understand the effects of age and different levels of submaximal LPPs on submental sEMG peak, average, and integrated values in healthy adults. Ninety community-dwelling healthy participants were categorized into three age groups (young: 20-39 years, middle age: 40-59 years, older: 60 ≥ years). sEMG and LPP measurements were collected concurrently. After placing the sEMG electrodes, the maximal isometric LPP was established using the Iowa oral performance instrument (IOPI) on the anterior tongue. sEMG recordings were conducted for three submaximal LPP levels, including 40%, 60%, and 80% of the maximum LPP. Two-way repeated measure ANOVAs were conducted to find the effects of age and varying LPP levels on mean sEMG peak, average, and integrated measures. A significant age by LPP level interaction was identified for sEMG peak [F (4, 172) = 4.116, p < 0.007, ηp2 = 0.087], sEMG average [F (4, 170) = 5.049, p < 0.001, ηp2 = 0.106], and sEMG integrated values [F (4, 170) = 4.179, p < 0.003, ηp2 = 0.090]. Post hoc testing demonstrated that, in general, sEMG values significantly increased with rising LPP levels, primarily for younger and middle-aged adults. Furthermore, at 80% of maximum LPP, older adults generated less sEMG average and integrated values than middle age (only significant for sEMG integrated value) and younger adults. Likewise, max LPP was lower in older adults compared with young and middle-aged groups. Submental sEMG has the potential to be incorporated into a skill-based lingual exercise paradigm to improve tongue function during swallowing. Moreover, submental sEMG can characterize some age-related subclinical changes in swallowing.

Shared and Separate Neuromuscular Underpinnings of Swallowing and Motor Speech Development in the School-Age Years

PURPOSE

Despite co-occurrence of swallowing and speech disorders in childhood, there is limited research on shared and separate neuromuscular underpinnings of these functions. The purpose of this study was to (a) compare neuromuscular control of swallowing and speech between younger and older children and (b) determine similarities and differences in neuromuscular control of swallowing and speech.

METHOD

Twenty-six typically developing children (thirteen 7- to 8-year-olds and thirteen 11- to 12-year-olds) completed this cross-sectional study. Neuromuscular control was evaluated using surface electromyography of submental muscles and superior and inferior orbicularis oris muscles during parallel tasks of swallowing and speech. Outcome measures included normalized mean amplitude, burst duration, time to peak amplitude, and bilateral synchrony, which were examined using mixed-effects models.

RESULTS

For normalized mean amplitude, burst duration, and time to peak amplitude, there were significant two- and three-way interactions between muscle group, task, and age group, indicating that older and younger children demonstrated different muscle activation patterns, and these patterns varied by muscle and task. No differences were noted between groups for bilateral synchrony. For parallel tasks, children demonstrated different magnitudes of normalized mean amplitude and time to peak amplitude of speech and swallowing. However, they demonstrated a similar pattern: increases in magnitude as task complexity increased.

CONCLUSIONS

Children continue to demonstrate refinement of their neuromuscular control of swallowing and speech between 7-8 and 11-12 years of age, and there are both shared and separate elements of neuromuscular control between these two vital functions. To improve generalizability of findings, future research should include longitudinal analysis of swallowing and speech development, as well as measures of central neurophysiology.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23796258.

Recent trends and challenges of surface electromyography in prosthetic applications

Surface electromyography (sEMG) meets extensive applications in the field of prosthesis in the current period. The effectiveness of sEMG in prosthesis applications has been verified by numerous revolutionary developments and extensive research attempts. A large volume of research and literature works have explored and validated the vast use of these signals in prostheses as an assistive technology. The objective of this paper is to conduct a systematic review and offer a detailed overview of the work record in the prosthesis and myoelectric interfaces framework. This review utilized a systematic search strategy to identify published articles discussing the state-of-the-art applications of sEMG in prostheses (including upper limb prosthesis and lower limb prostheses). Relevant studies were identified using electronic databases such as PubMed, IEEE Explore, SCOPUS, ScienceDirect, Google Scholar and Web of Science. Out of 3791 studies retrieved from the databases, 188 articles were found to be potentially relevant (after screening of abstracts and application of inclusion-exclusion criteria) and included in this review. This review presents an investigative analysis of sEMG-based prosthetic applications to assist the readers in making further advancements in this field. It also discusses the fundamental advantages and disadvantages of using sEMG in prosthetic applications. It also includes some important guidelines to follow in order to improve the performance of sEMG-based prosthesis. The findings of this study support the widespread use of sEMG in prosthetics. It is concluded that sEMG-based prosthesis technology, still in its sprouting phase, requires significant explorations for further development. Supplementary investigations are necessary in the direction of making a seamless mechanism of biomechatronics for sEMG-based prosthesis by cohesive efforts of robotic researchers and biomedical engineers.

An intensive neurorehabilitation programme with sEMG biofeedback to improve swallowing in idiopathic Parkinson's disease (IPD): A feasibility study

BACKGROUND

Studies suggest swallow intervention programmes that incorporate visual biofeedback and motor programming principles can improve swallowing and quality of life for people with idiopathic Parkinson's disease (IPD) and dysphagia. Few studies have examined outcomes using instrumentation.

AIMS

Using fibreoptic endoscopic examination of swallowing (FEES), this study examines the effectiveness of a neurorehabilitation intervention involving biofeedback via surface electromyography (sEMG) to improve swallowing in people with IPD, and to explore the feasibility of the intervention approach.

METHODS & PROCEDURES

We recruited 12 participants with IPD and dysphagia. A total of 10 completed the study. Intervention was delivered for 1 h per day, 5 days per week, for 4 weeks (20 h). Swallowing tasks using sEMG biofeedback incorporated principles of motor learning and neuroplasticity. Instrumental and non-instrumental assessment, including quality-of-life measures carried out at four different time points (two pre-treatment and two post-treatment). The final assessment was at 3 months post-intervention.

OUTCOME & RESULTS

Statistically significant improvement (p < 0.05) in oral intake methods (95% confidence interval (CI) = 4.70-5.50) and in pharyngeal residue from saliva (95% CI = 2.14-3.15) and solids (95% CI = 2.4-3.5) post-intervention were confirmed using FEES with improvements at 3 months. The intervention protocol was well tolerated. Participants reported positive change in saliva control and duration of mealtimes as well as unanticipated improvements in voice and cognitive attention.

CONCLUSIONS & IMPLICATIONS

An intensive neurorehabilitation with biofeedback shows positive effects in improving swallow function in IPD. This protocol is feasible with amendments to inform a larger clinical trial.

WHAT THIS PAPER ADDS

What is already known on the subject Biofeedback has positive effects on increasing swallowing function and quality of life in people with IPD and dysphagia. sEMG is the most common method used to deliver swallowing biofeedback in this population. The quality of the evidence on the intervention, based on findings from a recent systematic review, is low. Included studies in this review were heterogeneous in terms of type and frequency of biofeedback, study design and outcome measures. The majority of outcome measures were subjective and higher quality studies to examine the efficacy of biofeedback using sEMG are needed. What this study adds Recognizing the limitations of earlier studies, this within-subject feasibility study examined the efficacy and effectiveness of an intensive biofeedback intervention using sEMG in a sample of people with dysphagia and IPD. Valid and reliable outcome measures were used and repeated after a 3-month period. The feasibility of the methodological approach was also tested and a qualitative component was included in the study. Positive findings were evident. Qualitative information added new perspectives and provided direction for new outcomes to be included in future studies. This study helps to inform further research trials as well as clinical practice. Clinical implications of this study This intensive intervention using principles of neuroplasticity and motor programming with sEMG biofeedback led not only to positive swallowing outcomes but also to unexpected benefits such as improved voice production and general attention skills. No adverse events were reported. Improvement in function was retained at 3 months post-intervention. Despite the small sample size, participants described the benefits of the treatment, and enjoyed sEMG biofeedback tasks, especially using an sEMG game mode. This suggests that intensive biofeedback not only improved swallowing but also was acceptable to these participants. This intensive protocol has merit and is worth considering further in clinical practice.

Methods of Measuring Laryngeal Muscle Tension in Patients with Muscle Tension Dysphonia: A Scoping Review

BACKGROUND

In clinical practice and research relating to Muscle Tension Dysphonia (MTD), several laryngeal muscle tension measurement methods are used to diagnose, to identify specific muscle strengths and deficits, and to measure therapeutic outcomes. The variety and reliability of available measurement methods presents challenges within diagnosis and treatment. The lack of methodical standardization presents a barrier to homogeneous practice in this area. There is a need for a comprehensive scoping review of laryngeal muscle tension measurement methods.

STUDY DESIGN

Scoping review.

OBJECTIVES

(1) To identify current methods of laryngeal muscle measurement which have been developed or tested with people with MTD; and (2) To identify the construct/s measured, reliability, validity, ability to detect change, efficiency and accessibility of identified methods.

METHOD

This scoping review was conducted using the Arksey and O'Malley framework. Studies were identified through searches of 4 major databases. The reviewer independently assessed titles, abstracts, and full-text articles.

RESULTS

Twenty seven papers published from 2000 to 2022 that satisfied the inclusion criteria were selected from 194 studies. The papers showed a variety of approaches with regards to the measurement of laryngeal activity and tension in subjects with MTD. Just over a quarter (25.9%) were reviews of the validity of assessment methods of MTD, including surface electromyography (sEMG), while 22.2% discussed surface electromyography as a measurement of muscle activity in subjects with MTD. 96.3% used a published methodological framework.

CONCLUSIONS

Assessment methods for Primary MTD are multifaceted, including patient history, laryngoscopic examination, and voice-related musculoskeletal features. Potential use of objective measurement methods, including sEMG, Real Time Elastosonography, Magnetic Resonance Imaging was noted. Due to variability in assessment methods and results, there is a need for greater objective practical methodological standardization to ensure accurate diagnosis, appropriate care, and chart patient progress.

Toward a robust swallowing detection for an implantable active artificial larynx: a survey

Total laryngectomy consists in the removal of the larynx and is intended as a curative treatment for laryngeal cancer, but it leaves the patient with no possibility to breathe, talk, and swallow normally anymore. A tracheostomy is created to restore breathing through the throat, but the aero-digestive tracts are permanently separated and the air no longer passes through the nasal tracts, which allowed filtration, warming, humidification, olfaction, and acceleration of the air for better tissue oxygenation. As for phonation restoration, various techniques allow the patient to talk again. The main one consists of a tracheo-esophageal valve prosthesis that makes the air passes from the esophagus to the pharynx, and makes the air vibrate to allow speech through articulation. Finally, swallowing is possible through the original tract as it is now isolated from the trachea. Yet, many methods exist to detect and assess a swallowing, but none is intended as a definitive restoration technique of the natural airway, which would permanently close the tracheostomy and avoid its adverse effects. In addition, these methods are non-invasive and lack detection accuracy. The feasibility of an effective early detection of swallowing would allow to further develop an implantable active artificial larynx and therefore restore the aero-digestive tracts. A previous attempt has been made on an artificial larynx implanted in 2012, but no active detection was included and the system was completely mechanic. This led to residues in the airway because of the imperfect sealing of the mechanism. An active swallowing detection coupled with indwelling measurements would thus likely add a significant reliability on such a system as it would allow to actively close an artificial larynx. So, after a brief explanation of the swallowing mechanism, this survey intends to first provide a detailed consideration of the anatomical region involved in swallowing, with a detection perspective. Second, the swallowing mechanism following total laryngectomy surgery is detailed. Third, the current non-invasive swallowing detection technique and their limitations are discussed. Finally, the previous points are explored with regard to the inherent requirements for the feasibility of an effective swallowing detection for an artificial larynx. Graphical Abstract.

A robust HD-sEMG sensor suitable for convenient acquisition of muscle activity in clinical post-stroke dysphagia

Objective.A flexible high-density surface electromyography (HD-sEMG) sensor combined with an adaptive algorithm was used to collect and analyze the swallowing activities of patients with Post-stroke dysphagia.Approach.The electrode frame, modified electrode, and bonded substrate of the sensor were fabricated using a flexible printed circuit process, controlled drop coating, and molding, respectively. The adaptation algorithm was achieved by using Laplace and Teager-Kaiser energy operators to extract active segments, a cross-correlation coefficient matrix (CCCM) to evaluate synergy, and multi-frame real-time dynamic root mean square (RMS) to visualize spatiotemporal information to screen lesions and level of dysphagia. Finally, support vector machines (SVM) were adopted to explore the classification accuracy of sex, age, and lesion location with small sample sizes.Main results.The sensor not only has a basic low contact impedance (0.262 kΩ) and high signal-to-noise ratio (37.284 ± 1.088 dB) but also achieves other characteristics suitable for clinical applications, such as flexibility (747.67 kPa) and durability (1000 times) balance, simple operation (including initial, repeated, and replacement use), and low cost ($ 15.2). The three conclusions are as follows. CCCM can be used as a criterion for judging the unbalanced muscle region of the patient's neck and can accurately locate unbalanced muscles. The RMS cloud map provides the time consumption, swallowing times, and unbalanced areas. When the lesion location involves the left and right hemispheres simultaneously, it can be used as an evidence of relatively severely unbalanced areas. The classification accuracy of SVM in terms of sex, age, and lesion location was as high as 100%.Significance.The HD-sEMG sensor in this study and the adaptation algorithm will contribute to the establishment of a larger-scale database in the future to establish more detailed and accurate quantitative standards, which will be the basis for developing more optimized screening mechanisms and rehabilitation assessment methods.

Fatigue-Related Change in Surface Electromyographic Activities of the Perilaryngeal Muscles

PURPOSE

This study set out to quantify the fatigue-related changes in surface electromyographic (sEMG) activities of the perilaryngeal muscles following a vocal loading task.

METHOD

Thirty-six young healthy participants (M _age = 22.4 years) with normal voice performed karaoke singing for at least 100 min. Before the singing task, all participants underwent the sEMG measure and completed a Perceived Vocal Fatigue Score (P-VFS) questionnaire. After the singing task, all participants were immediately measured with the P-VFS again. Half of the participants were then measured for their sEMG immediately after their karaoke singing task, and the other half were given 20 min of rest before undertaking the sEMG measure. The P-VFS and the median frequency (MDF) of the sEMG signals collected from the suprahyoid, infrahyoid, and sternocleidomastoid muscles before and after the singing task were compared using a linear mixed-effects model.

RESULTS

All participants reported a perceived vocal fatigue after singing, with a significantly increased P-VFS. Compared with the presinging baseline, the MDF of the sEMG signals in perilaryngeal muscles was significantly lower immediately after the singing task. Such a significant difference was also found after 20 min following the singing task.

CONCLUSIONS

The MDF analysis of the sEMG signals could identify and quantify the performance vocal fatigue contributed by perilaryngeal muscles following a vocal loading task. The findings also showed that such fatigue in perilaryngeal muscles, as far as sEMG activities are concerned, can last for at least 20 min.

Effects of Midface Hypoplasia and Facial Hypotonia at Rest and During Clenching on Drooling in Down syndrome Children

BACKGROUND: Down syndrome is a chromosome 21 disorder and the most common cause of physical abnormalities including midface hypoplasia, facial hypotonia, and also drooling. Drooling is unintentional anterior salivary flow from the mouth. The objectives of the study is to determine and analyze the effects of midfacial hypoplasia and facial hypotonia on drooling in Down syndrome children. Subject and method: METHODS: of the research is analytic correlational. Sample retrievement using purposive sampling technique and obtained 20 samples that fulfills the inclusive criterias, consisting of 13 boys and 7 girls with an age range of 6 to 16 years old. RESULTS AND DISCUSSION: The results were tested statistically by Kendall Coefficient of Concordance Test and Spearman Coefficient of Rank Correlation Test. The results showed that the effect of midfacial hypoplasia, facial hypotonia at rest, and during clenching on drooling is very significant (p-value 0.0002) with Kendall Coefficient of Concordance. Spearman Coefficient of Rank Correlation test results show correlation of midface hypoplasia on drooling is not significant (p-value 0,1265). Facial hypotonia at rest has a very significant correlation on drooling (p-value 0,0000) and during clenching also has a very significant correlation (p-value 0,0000). CONCLUSION: Conclusion of the research is there are effects of midface hypoplasia, facial hypotonia at rest and facial hypotonia during clenching on drooling, also facial hypotonia at rest and facial hypotonia during clenching on drooling, but no effect of midface hypoplasia on drooling in Down syndrome children.

Effect of Vocal Therapy Associated With TENS in Women With Behavioral Dysphonia

PURPOSE

This study aimed to investigate the effect of transcutaneous electrical nerve stimulation (TENS) associated with vocal therapy in women with behavioral dysphonia.

METHOD

Seventeen women with behavioral dysphonia were divided into an experimental group (n = 8) and a placebo group (n = 9). All were submitted to six sessions of vocal therapy, according to the Comprehensive Voice Rehabilitation Program. In the experimental group, therapy was associated with TENS (30 minutes) and in the placebo group, the electrodes were placed and the equipment remained off. The vocal handicap, the voice through the acoustic and auditory perception evaluation, the electrical activity, and the superficial temperature of the suprahyoid and infrahyoid muscles were evaluated. Pre and post data were compared by parametric and nonparametric tests.

RESULTS

There was a decreased in vocal handicap of the placebo group (P = 0.002) and a decreased in the percentage of electrical activity of the right (P = 0.036) and left (P = 0.017) infrahyoid muscles of the experimental group in vowel emission and sequential speech (P = 0.036). There was an increase in temperature in the right infrahyoid region in vowel emission (P = 0.027) and the temperature difference decreased quantitatively between the supra and infrahyoid regions in the experimental group.

CONCLUSION

TENS associated with vocal therapy reduced the electrical activity of the infrahyoid muscles and balance the temperature between the supra- and infrahyoid regions in women with behavioral dysphonia.

Non-invasive assessment of swallowing using flexible high-density electromyography arrays

Swallowing is a vital function that serves to safely transport food and fluid to the stomach, while simultaneously protecting our airways. Evaluation of swallowing is important for the diagnosis and rehabilitation of individuals with dysphagia, a disorder of swallowing. Flexible high-density surface electromyography (HD sEMG) arrays were designed and fabricated to span the floor of mouth and neck muscles. These arrays were applied on 6 healthy participants over duplicate recording sessions. During each recording session, participants performed three different swallowing motor tasks. The HD sEMG signals were filtered and tasks extracted. For each task, the RMS amplitude was computed, visualized, and compared. Dynamic motor coordination was evident in the filtered signals traces, with different electrode locations showing unique temporal activations. The 2D topographical maps allowed the location of different RMS intensities to be visualized, revealing qualitatively similar patterns across participants and tasks. These motor task trends were also seen within RMS quantifications. The RMS metric across all participants identified significant differences between non-effortful 3 ml and effortful 3 ml swallow tasks ( p=0.006) and there was a minimal variation of 3.1±1.9 μV RMS for repeated recording sessions by each participant. The HD-sEMG array successfully recorded differences in muscle activations during swallowing and was able to discern between two different motor tasks. The arrays offers a spatially detailed non-invasive assessment of the neuromuscular performance of swallowing. Clinical Relevance- The utility of HD-sEMG arrays for evaluation of the muscles involved in swallowing could enable diagnosis and rehabilitation of individuals with dysphagia.

Relationship between demographic and cephalometric measures and electromyographic activityu of the facial musculature. A preliminary study in children and adolescents

Surface electromyography (EMGS) is used to evaluate the electromyographic activity of the orofacial musculature at rest, or when performing certain activities such as swallowing saliva or water, or tasks of maximum voluntary contraction. Numerous studies have evaluated the relationship between facial morphology and muscle activity, with contradictory results. The aim of this study was to determine whether there are significant differences in the electromyographic activity of the orofacial musculature as a function of the variables: age, height, weight, facial pattern and skeletal class. For this purpose, 81 patients with dental malocclusion were selected (35 males and 46 females, aged 6 to 17 years). Bilateral EMGS activity of the temporalis, masseter, orbicularis oris of the upper and lower lip of the mouth and suprahyoid muscles was measured in the resting position, maximum voluntary contraction and swallowing of saliva 2 ml of water. The results obtained show that the mandibular plane and the ANB angle present significant differences in all the variables of EMGS activity; however, the facial pattern only shows significant differences in the mean deviation of muscle activity. Skeletal class shows no significant effect on any of the EMGS variables recorded. The variables Age, Weight and Height show significant results on all EMGS activity variables. The variable Sex only shows significant results in the mean deviation of muscle activity. This work supports previous studies that found no significant results based on facial pattern and skeletal class. It would be advisable to perform a more exhaustive analysis of the muscles involved and their relationship between the different tasks evaluated, and to increase the sample size of patients with skeletal Class III in order to reach more definitive conclusions.

Swallowing and laryngeal complications in lung and heart transplantation: Etiologies and diagnosis

Despite continued surgical advancements in the field of cardiothoracic transplantation, post-operative complications remain a burden for the patient and the multidisciplinary team. Lesser-known complications including swallowing disorders (dysphagia), and voice disorders (dysphonia), are now being reported. Such disorders are known to be associated with increased morbidity and mortality in other medical populations, however their etiology amongst the heart and lung transplant populations has received little attention in the literature. This paper explores the potential mechanisms of oropharyngeal dysphagia and dysphonia following transplantation and discusses optimal modalities of diagnostic evaluation and management. A greater understanding of the implications of swallowing and laryngeal dysfunction in the heart and lung transplant populations is important to expedite early diagnosis and management in order to optimize patient outcomes, minimize allograft injury and improve quality of life.

Biofeedback as an Adjunctive Treatment for Post-stroke Dysphagia: A Pilot-Randomized Controlled Trial

BACKGROUND AND PURPOSE

Post-stroke dysphagia affects almost half of the survivors and severely influences quality of life, thus becoming swallowing rehabilitation of paramount importance. However, there is little adequate evidence on which the best rehabilitative strategy can be. Surface electromyography (sEMG) allows for recording swallowing muscles' activity and provides real time visual feedback, as a biofeedback adjunctive technique to improve treatment outcome. This study aimed to analyze the effectiveness of biofeedback rehabilitation of swallowing through sEMG compared to standard techniques, in post-stroke dysphagia.

METHODS

A pilot-randomized controlled trial included 17 patients diagnosed with post-stroke dysphagia. Nine underwent sEMG-biofeedback rehabilitation; seven controls were submitted to control treatment, one dropout. The primary outcome was the functional oral intake scale (FOIS), secondary outcomes was pharyngeal clearance and safe swallowing, assessed through fiberoptic endoscopic evaluation of swallowing (FEES).

RESULTS

FOIS improved in all patients, regardless of treatment. sEMG-biofeedback rehabilitation led to improvements of the pharyngeal clearance and swallowing safety. The rehabilitative effects appeared stable at 2-months follow-up.

CONCLUSIONS

The application of biofeedback based on sEMG in post-stroke dysphagia patients resulted in an effective rehabilitative technique, in particular for pharyngeal clearance improvements and safe swallowing, thus reducing the risk of aspiration and malnutrition.

Sports Related Concussion Impacts Speech Rate and Muscle Physiology

OBJECTIVE

Establish objective and subjective speech rate and muscle function differences between athletes with and without sports related concussion (SRC) histories and provide potential motor speech evaluation in SRC.

METHODS

Over 1,110 speech samples were obtained from 30, 19-22 year-old athletes who had sustained an SRC within the past 2 years and 30 pair-wise matched control athletes with no history of SRC. Speech rate was measured via average time per syllable, average unvoiced time per syllable, and expert perceptual judgment. Speech muscle function was measured via surface electromyography over the obicularis oris, masseter, and segmental triangle. Group differences were assessed using MANOVA, bootstrapping and predictive ROC analyses.

RESULTS

Athletes with SRC had slower speech rates during DDK tasks than controls as evidenced by longer average time per syllable longer average unvoiced time per syllable and expert judgment of slowed rate. Rate measures were predictive of concussion history. Further, athletes with SRC required more speech muscle activation than controls to complete DDK tasks.

CONCLUSION

Clear evidence of slowed speech and increased muscle activation during the completion of DDK tasks in athletes with SRC histories relative to controls. Future work should examine speech rate in acute concussion.

Surgeon Positioning During Awake Laryngeal Surgery: An Ergonomic Analysis

OBJECTIVES

While it is acknowledged that otolaryngologists performing microlaryngeal surgery can develop musculoskeletal symptoms due to suboptimal body positioning relative to the patient, flexible laryngoscopy and awake laryngeal surgeries (ALSs) can also pose ergonomic risk. This prospective study measured the effects of posture during ergonomically good and bad positions during laryngoscopy using ergonomic analysis, skin-surface electromyography (EMG), and self-reported pain ratings.

STUDY DESIGN

Prospective cohort study.

METHODS

Eight participants trained in laryngoscopy assumed four ergonomically distinct standing positions (side/near, side/far, front/near, front/far) at three different heights (neutral-top of patient's head in line with examiner's shoulder, high-6 inches above neutral, and low-6 inches below neutral) in relation to a simulated patient. Participants' postures were analyzed using the validated Rapid Upper Limb Assessment (RULA, 1 [best] to 7 [worst]) tool for the 12 positions. Participants then simulated ALS for 10 minutes in a bad position (low-side-far) and a good position (neutral-front-near) with 12 EMG sensors positioned on the limbs and torso.

RESULTS

The position with the worst RULA score was the side/near/high (7.0), and the best was the front/near/neutral (4.5). EMG measurements revealed significant differences between simulated surgery in the bad and good positions, with bad position eliciting an average of 206% greater EMG root-mean-squared magnitude across all sampled muscles compared to the good posture (paired t-test, df = 7, P < .01), consistent with self-reported fatigue/pain when positioned poorly.

CONCLUSION

Quantitative and qualitative measurements demonstrate the impact of surgeon posture during simulated laryngoscopy and suggest ergonomically beneficial posture that should facilitate ALSs.

LEVEL OF EVIDENCE

3 Laryngoscope, 2021.

Surface Electromyography-Based Recognition, Synthesis, and Perception of Prosodic Subvocal Speech

Purpose This study aimed to evaluate a novel communication system designed to translate surface electromyographic (sEMG) signals from articulatory muscles into speech using a personalized, digital voice. The system was evaluated for word recognition, prosodic classification, and listener perception of synthesized speech. Method sEMG signals were recorded from the face and neck as speakers with (n = 4) and without (n = 4) laryngectomy subvocally recited (silently mouthed) a speech corpus comprising 750 phrases (150 phrases with variable phrase-level stress). Corpus tokens were then translated into speech via personalized voice synthesis (n = 8 synthetic voices) and compared against phrases produced by each speaker when using their typical mode of communication (n = 4 natural voices, n = 4 electrolaryngeal [EL] voices). Naïve listeners (n = 12) evaluated synthetic, natural, and EL speech for acceptability and intelligibility in a visual sort-and-rate task, as well as phrasal stress discriminability via a classification mechanism. Results Recorded sEMG signals were processed to translate sEMG muscle activity into lexical content and categorize variations in phrase-level stress, achieving a mean accuracy of 96.3% (SD = 3.10%) and 91.2% (SD = 4.46%), respectively. Synthetic speech was significantly higher in acceptability and intelligibility than EL speech, also leading to greater phrasal stress classification accuracy, whereas natural speech was rated as the most acceptable and intelligible, with the greatest phrasal stress classification accuracy. Conclusion This proof-of-concept study establishes the feasibility of using subvocal sEMG-based alternative communication not only for lexical recognition but also for prosodic communication in healthy individuals, as well as those living with vocal impairments and residual articulatory function. Supplemental Material https://doi.org/10.23641/asha.14558481.

Multimodal Data Fusion of Electromyography and Acoustic Signals for Thai Syllable Recognition

Speech disorders such as dysarthria are common and frequent after suffering a stroke. Speech rehabilitation performed by a speech-language pathologist is needed to improve and recover. However, in Thailand, there is a shortage of speech-language pathologists. In this paper, we present a syllable recognition system, which can be deployable in a speech rehabilitation system to provide support to the limited speech-language pathologists available. The proposed system is based on a multimodal fusion of acoustic signal and surface electromyography (sEMG) collected from facial muscles. Multimodal data fusion is studied to improve signal collection under noisy situations while reducing the number of electrodes needed. The signals are simultaneously collected while articulating 12 Thai syllables designed for rehabilitation exercises. Several features are extracted from sEMG signals and five channels are studied. The best combination of features and channels is chosen to be fused with the mel-frequency cepstral coefficients extracted from the acoustic signal. The feature vector from each signal source is projected by spectral regression extreme learning machine and concatenated. Data from seven healthy subjects were collected for evaluation purposes. Results show that the multimodal fusion outperforms the use of a single signal source achieving up to [Formula: see text] of accuracy. In other words, an accuracy improvement up to [Formula: see text] can be achieved when using the proposed multimodal fusion. Moreover, its low standard deviations in classification accuracy compared to those from the unimodal fusion indicate the improvement in the robustness of the syllable recognition.

A comparison of swallow-related submandibular contraction amplitude and duration in people with Parkinson's disease and healthy controls

PURPOSE

To compare the contraction amplitude and contraction duration of submandibular muscles during the pharyngeal stage of swallowing in people with Parkinson's disease (PD) compared to normal controls.

METHOD

A prospective cross-sectional study design was utilised to recruit 24 participants from the regional area. A total of 14 people with PD and 10 healthy controls (HC) were recruited. Participants swallowed three volumes of thin liquid (5mL, 10mL, 15mL) while the activity of the submandibular muscles was recorded using surface electromyography. Measurements of contraction amplitude ratio (normalised to a maximum voluntary contraction) and contraction duration were computed from recorded electromyographic signals. Receiver Operating Characteristics (ROC) were computed for variables associated with significant main effects.

RESULT

Analyses revealed a significant effect of group on contraction amplitude ratio but not contraction duration. There were no significant effects of bolus volume on the dependent variables. ROC analysis indicated that contraction amplitude ratio accurately predicted group assignment in 77% cases.

CONCLUSION

Findings revealed that a majority of people with PD in this study utilised a greater percentage of their maximum contraction force in submandibular muscles when swallowing compared to normal controls. Further research is needed to determine if this inefficiency is consistent across larger samples and whether it is due to elevated baseline muscle activity, a compensatory behaviour to accomplish a more effective swallow, or both.

The Relationship Between Voice Onset Time and Increase in Vocal Effort and Fundamental Frequency

Purpose Prior work suggests that voice onset time (VOT) may be impacted by laryngeal tension: VOT means decrease when individuals with typical voices increase their fundamental frequency (f o) and VOT variability is increased in individuals with vocal hyperfunction, a voice disorder characterized by increased laryngeal tension. This study further explored the relationship between VOT and laryngeal tension during increased f o, vocal effort, and vocal strain. Method Sixteen typical speakers of American English were instructed to produce VOT utterances under four conditions: baseline, high pitch, effort, and strain. Repeated-measures analysis of variance models were used to analyze the effects of condition on VOT means and standard deviations (SDs); pairwise comparisons were used to determine significant differences between conditions. Results Voicing, condition, and their interaction significantly affected VOT means. Voiceless VOT means significantly decreased for high pitch (p < .001) relative to baseline; however, no changes in voiceless VOT means were found for effort or strain relative to baseline. Although condition had a significant effect on VOT SDs, there were no significant differences between effort, strain, and high pitch conditions relative to baseline. Conclusions Speakers with typical voices likely engage different musculature to increase pitch than to increase vocal effort and strain. The increased VOT variability present with vocal hyperfunction is not seen in individuals with typical voices using increased effort and strain, supporting the assertion that this feature of vocal hyperfunction may be related to disordered vocal motor control rather than resulting from effortful voice production.

Clinical and Electromyographic Assessment of Swallowing in Individuals with Functional Dysphonia Associated with Dysphagia Due to Muscle Tension or Atypical Swallowing

Introduction: Over the past few years, attention has been paid to the coexistence of dysphonia with dysphagia, in the context of functional disorders. The aim of this work was to objectify logopaedic examination of dysphonic patients with coexisting swallowing difficulties by surface electromyography. Methods: The material of the work included 58 patients with muscle tension dysphonia (MTD). Each patient underwent otolaryngologic, phoniatric and logopaedic examination. We collected information about medical history and asked patients to fill out Reflux Symptom Index (RSI), Eating Assessment Tool (EAT-10), Dysphagia Handicap Index (DHI) and Swallowing Disorder Scale (SDS). The algorithm of dysphagia diagnostics in our clinic assumes parallel surface electromyography (SEMG) during Functional Endoscopic Evaluation of Swallowing. Results: In comparison to patients suffering from atypical swallowing, patients with muscle tension dysphagia (MTDg) obtained higher values from almost all questionnaires. Logopaedic evaluation revealed abnormalities in the structure and efficiency of the articulatory organs and in the assessment of primary functions. Patients with more abnormalities in logopaedic examination had significantly higher infrahyoid muscle activity during swallowing observed in EMG. Patients with non-normative swallowing pattern had significantly greater asymmetry of the average and maximum amplitude of masseters, as well as submental muscles. Patients with higher percent of muscles asymmetry gained higher scores in questionnaires. Conclusions: Surface electromyography objectifies logopaedic examination of patients with swallowing difficulties. The results of this work showed that, apart from longer swallows, patients with MTDg differ from patients with non-normative swallowing patterns in the muscle activity measured by SEMG, abnormalities in logopaedic evaluation and the severity of complaints reported by patients.

A comparison of the head lift exercise and recline exercise in patients with chronic head and neck cancer post-radiation

BACKGROUND

Patients who undergo surgery and adjuvant radiation treatment for head and neck cancer often develop dysphagia as a result of this treatment. Improvements in swallow function may be achieved with exercise. The goal of this pilot study was to compare the effectiveness and perceived difficulty of using the head lift exercise and the recline exercise to activate the suprahyoid musculature in 8 individuals with a history of head and neck cancer.

METHOD

Muscle activation using surface electromyography was examined to determine if the recline exercise activates the suprahyoid muscle groups to the same degree as the head lift exercise. Participants also rated the exertion they experienced to assess how easily patients are able to complete the exercises.

RESULTS

The majority of participants completed both exercises in their entirety on their first attempt. However, ratings of perceived exertion were significantly lower for the recline exercise than the head lift exercise. The head lift exercise activated the suprahyoid musculature to a significantly greater degree than the recline exercise.

CONCLUSION

The recline exercise, in comparison with the head lift exercise, is easier for participants to complete and results in significantly reduced perceptions of fatigue. Results of this study indicate that the recline exercise may be a good potential substitute for the head lift exercise in patient populations that are incapable of performing the head lift exercise, but that the head lift exercise should be prescribed whenever it is viable as it activates target musculature more effectively than the recline exercise.

Effect of Volitional Effort on Submental Surface Electromyographic Activity During Healthy Swallowing

The effortful swallowing technique aims to compensate for or rehabilitate impaired swallowing by using maximal volitional effort to behaviorally modify aspects of swallowing physiology. Given that swallowing is a submaximal task, swallowing at submaximal levels has recently been suggested as a more task-specific therapeutic technique. The aim of this study was to investigate differences in muscle activity during minimum, regular, and maximum effort swallowing of different boluses and across different ages, with the goal of characterizing the task specificity of minimum effort and maximum effort swallowing. Forty-three healthy adults (22 female) representing four age groups (20-39, 40-59, 60-79, and 80 + years) participated in the study. They were verbally cued to swallow saliva and 5 mL water boluses using participant-determined minimum, regular, and maximum levels of effort, in randomized order. sEMG peak amplitude and duration of each swallow were measured. Linear mixed effects analyses demonstrated that compared to regular effort swallowing, maximum effort swallowing resulted in increased sEMG amplitude (p < .001) and prolonged duration (p < .001), while minimum effort swallowing resulted in decreased amplitude (p < .001) but no significant difference in duration (p = .06). These effects occurred regardless of age or bolus type. Differences in sEMG activity were smaller between regular and minimum effort swallowing than regular and maximum effort swallowing. Both increasing and decreasing volitional efforts during swallowing translate to significant modulation of muscle activity. However, regular swallowing is more similar to minimal effort swallowing. Results reinforce the concept of swallowing as a submaximal task, and provide insight into the development of sEMG biofeedback techniques for rehabilitation.

Classification of Stroke Patients With Dysphagia Into Subgroups Based on Patterns of Submental Muscle Strength and Skill Impairment

OBJECTIVES

To identify and characterize subgroups of stroke patients with clinical signs of dysphagia, based on swallowing-related strength and skill impairments of the submental muscle group.

DESIGN

Prospective observational study.

SETTING

Inpatient rehabilitation centers and community dwellings.

PARTICIPANTS

Individuals (N=114), including stroke patients with dysphagia (n=55) and 2 control groups including myopathic patients with dysphagia (n=19) and healthy volunteers (n=40) were included in this study.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Novel clinical assessment of strength (force generation) and skill (spatial and temporal precision of muscle activation) of the submental muscle group during swallowing and nonswallowing behaviors, using surface electromyography and dynamometry.

RESULTS

Hierarchical cluster analysis revealed 4 clusters, which could be broadly characterized as cluster 1: intact strength and skill, cluster 2: poor strength and poor nonswallowing skill, cluster 3: poor strength, and cluster 4: poor strength and poor swallowing skill. Membership in cluster was significantly associated with medical diagnosis (P<.001). The majority of healthy and myopathic participants were assigned to clusters 1 and 3, respectively, whereas stroke patients were found in all 4 clusters. Skill outcome measures were more predictive of cluster assignment than strength measures.

CONCLUSIONS

Although healthy and myopathic participants demonstrated predominantly homogeneous swallowing patterns of submental muscle function within their etiology, several subgroups were identified within stroke, possibly reflecting different subtypes of swallowing function. Future research should focus on the nature and rehabilitation needs of these subtypes. Assessment of skill in swallowing may be an important but overlooked aspect of rehabilitation.

Validation of a Novel Wearable Electromyography Patch for Monitoring Submental Muscle Activity During Swallowing: A Randomized Crossover Trial

Purpose Surface electromyography (sEMG) is often used for biofeedback during swallowing rehabilitation. However, commercially available sEMG electrodes are not optimized for the head and neck area, have rigid form, and are mostly available in large medical centers. We developed an ultrathin, soft, and flexible sEMG patch, specifically designed to conform to the submental anatomy and which will be ultimately incorporated into a telehealth system. To validate this first-generation sEMG patch, we compared its safety, efficiency, and signal quality in monitoring submental muscle activity with that of widely used conventional sEMG electrodes. Method A randomized crossover design was used to compare the experimental sEMG patch with conventional (snap-on) sEMG electrodes. Participants completed the same experimental protocol with both electrodes in counterbalanced order. Swallow trials included five trials of 5- and 10-ml water. Comparisons were made on (a) signal-related factors: signal-to-noise ratio (SNR), baseline amplitude, normalized mean amplitude, and sEMG burst duration and (b) safety/preclinical factors: safety/adverse effects, efficiency of electrode placement, and satisfaction/comfort. Noninferiority and equivalence tests were used to examine signal-related factors. Paired t tests and descriptive statistics were used to examine safety/preclinical factors. Results Forty healthy adults participated (24 women, M _age = 67.5 years). Signal-related factors: SNR of the experimental patch was not inferior to the SNR of the conventional electrodes (p < .0056). Similarly, baseline amplitude obtained with the experimental patch was not inferior to that obtained with conventional electrodes (p < .0001). Finally, normalized amplitude values were equivalent across swallows (5 ml: p < .025; 10 ml: p < .0012), and sEMG burst duration was also equivalent (5 ml: p < .0001; 10 ml: p < .0001). Safety/preclinical factors: The experimental patch resulted in fewer mild adverse effects. Participant satisfaction was higher with the experimental patch (p = .0476, d = 0.226). Conclusions Our new wearable sEMG patch is equivalent with widely used conventional sEMG electrodes in terms of technical performance. In addition, our patch is safe, and healthy older adults are satisfied with it. With lessons learned from the current COVID-19 pandemic, efforts to develop optimal swallowing telerehabilitation devices are more urgent than ever. Upon further validation, this new technology has the potential to improve rehabilitation and telerehabilitation efforts for patients with dysphagia. Supplemental Material https://doi.org/10.23641/asha.12915509.

Scalogram-energy based segmentation of surface electromyography signals from swallowing related muscles

BACKGROUND AND OBJECTIVE

The swallowing is a complex process mediated by the central nervous system, that implies voluntary and involuntary components, including 26 pairs of muscles. Non-invasive strategies, including the surface electromyography (sEMG), have been proposed to evaluate the swallowing. However, such analyses have been mostly descriptive, and the detection of neuromuscular activity has been limited to the visual inspection (VIS). Nonetheless, the VIS lacks reliability since the swallowing related muscles have small size, they are not completely shallow, suffer from cross-talk and have low signal-to-noise ratio (SNR). In this way, we propose a wavelet based method to automatically detect activations in sEMG signals acquired during praxis and swallowing tasks.

METHODS

The proposed strategy, namely Scalogram-Energy based Segmentation method, was applied on sEMG signals recorded in masseteric, orbicular, supra- and infrahyoid muscles. The method was trained in a database of 35 healthy subjects by the use of multi-objective genetic algorithms and tested via cross-validation, aiming to maximize the F₁ score and minimize the timing error between the automatic and VIS related marks. Furthermore, the proposed method was tested in a database of semi-synthetic signals with variable SNR built from signals collected from 10 individuals. Additionally, the method was compared with a double threshold based algorithm as well as with other based on energy and morphological operators.

RESULTS

The algorithm achieved a F₁ score of 0.82 and almost 13 ms of error in the estimation of onset and offset. Afterwards, we applied the optimized algorithm to a set with semi-synthetic signals with variable SNR, that achieved F₁ score of 0.85 for SNR=6 dB and 0.97 for SNR=8 and 10 dB. The mean of the timing error was smaller than 9 ms for SNR=6,8 and 10 dB. The method was also compared with a double threshold based algorithm as well as with other based on energy and morphological operators.

CONCLUSIONS

The proposed method shown to be useful to automatically analyze the electrophysiological activity associated to praxis and swallowing process. Nonetheless, the obtained results could be extended to other sEMG related applications.

Evaluation of Swallowing Related Muscle Activity by Means of Concentric Ring Electrodes

Surface electromyography (sEMG) can be helpful for evaluating swallowing related muscle activity. Conventional recordings with disc electrodes suffer from significant crosstalk from adjacent muscles and electrode-to-muscle fiber orientation problems, while concentric ring electrodes (CREs) offer enhanced spatial selectivity and axial isotropy. The aim of this work was to evaluate CRE performance in sEMG recordings of the swallowing muscles. Bipolar recordings were taken from 21 healthy young volunteers when swallowing saliva, water and yogurt, first with a conventional disc and then with a CRE. The signals were characterized by the root-mean-square amplitude, signal-to-noise ratio, myopulse, zero-crossings, median frequency, bandwidth and bilateral muscle cross-correlations. The results showed that CREs have advantages in the sEMG analysis of swallowing muscles, including enhanced spatial selectivity and the associated reduction in crosstalk, the ability to pick up a wider range of EMG frequency components and easier electrode placement thanks to its radial symmetry. However, technical changes are recommended in the future to ensure that the lower CRE signal amplitude does not significantly affect its quality. CREs show great potential for improving the clinical monitoring and evaluation of swallowing muscle activity. Future work on pathological subjects will assess the possible advantages of CREs in dysphagia monitoring and diagnosis.

Inner experience differs in rumination and distraction without a change in electromyographical correlates of inner speech

Ruminative thought is a style of thinking which involves repetitively focusing upon one's own negative mood, its causes and its consequences. The negative effects of rumination are well-documented, but comparatively little is known about how rumination is experienced. The evaluative nature of rumination suggests that it could involve more inner speech than non-ruminative states. The present study (N = 31) combined facial electromyography and self-report questionnaires to determine the type of inner experience that occurs in rumination. The results showed that induced rumination involved similar levels of muscle activity related to inner speech as periods of induced distraction. However, experience sampling and questionnaire responses showed that rumination involved more verbal thought, and also involved more evaluative and dialogic inner speech than distraction. These findings contribute to the understanding of inner speech as a flexible phenomenon and confirms the importance of employing multiple methods to investigate inner speech. Future research should clarify the link between inner speech in rumination and its negative effects on wellbeing.

Cursor Click Modality in an Accelerometer-Based Computer Access Device

The purpose of this study is to investigate the effects of different cursor click modalities in an alternative computer access device using accelerometry from head tilt to control cursor movement. Eighteen healthy adults performed a target acquisition task using the device with five different cursor click modalities, while maintaining cursor movement control via accelerometry. Three dwell-based click modalities with dwell times of 0.5 s, 1.0 s, and 1.5 s were tested. Two surface electromyography-based click modalities - with the sensor placed next to the eye for a blink and above the eyebrow for a brow raise - were tested. Performance was evaluated using metrics of target selection accuracy, path efficiency, target selection time, and user effort. Surface electromyography-based click modalities were as fast as the shortest dwell time and as accurate as the longest dwell time, and also minimized user effort. Three of the four performance metrics were not affected by sensor location. Future studies will investigate if these results are similar in individuals with neuromuscular disorders.

Formant-Estimated Vocal Tract Length and Extrinsic Laryngeal Muscle Activation During Modulation of Vocal Effort in Healthy Speakers

Purpose The goal of this study was to explore the relationships among vocal effort, extrinsic laryngeal muscle activity, and vocal tract length (VTL) within healthy speakers. We hypothesized that increased vocal effort would result in increased suprahyoid muscle activation and decreased VTL, as previously observed in individuals with vocal hyperfunction. Method Twenty-eight healthy speakers of American English produced vowel-consonant-vowel utterances under varying levels of vocal effort. VTL was estimated from the vowel formants. Three surface electromyography sensors measured the activation of the suprahyoid and infrahyoid muscle groups. A general linear model was used to investigate the effects of vocal effort level and surface electromyography on VTL. Two additional general linear models were used to investigate the effects of vocal effort on suprahyoid and infrahyoid muscle activities. Results Neither vocal effort nor extrinsic muscle activity showed significant effects on VTL; however, the degree of extrinsic muscle activity of both suprahyoid and infrahyoid muscle groups increased with increases in vocal effort. Conclusion Increasing vocal effort resulted in increased activation of both suprahyoid and infrahyoid musculature in healthy adults, with no change to VTL.

Flexible submental sensor patch with remote monitoring controls for management of oropharyngeal swallowing disorders

Successful rehabilitation of oropharyngeal swallowing disorders (i.e., dysphagia) requires frequent performance of head/neck exercises that primarily rely on expensive biofeedback devices, often only available in large medical centers. This directly affects treatment compliance and outcomes, and highlights the need to develop a portable and inexpensive remote monitoring system for the telerehabilitation of dysphagia. Here, we present the development and preliminarily validation of a skin-mountable sensor patch that can fit on the curvature of the submental (under the chin) area noninvasively and provide simultaneous remote monitoring of muscle activity and laryngeal movement during swallowing tasks and maneuvers. This sensor patch incorporates an optimal design that allows for the accurate recording of submental muscle activity during swallowing and is characterized by ease of use, accessibility, reusability, and cost-effectiveness. Preliminary studies on a patient with Parkinson's disease and dysphagia, and on a healthy control participant demonstrate the feasibility and effectiveness of this system.

Biological surface electromyographic switch and necklace-type button switch control as an augmentative and alternative communication input device: a feasibility study

Augmentative and alternative communication (AAC) is an approach used to supplement, improve, and support the communication of those with speech or language impairments. We developed an AAC device for diverse approaches, using an electromyographic (EMG) switch and a necklace-type button switch. The EMG switch comprised an EMG signal processor and a switch interface processor. EMG signals were processed using an electrode through the stages of signal acquisition, amplification, filtering, rectification, and smoothing. In the switch interface processor, the microprocessor determined the switch as ON or OFF in response to an input EMG signal and then converted the EMG signal into a keyboard signal, which was transmitted to a smart device via Bluetooth communication. A similar transmission process was used for the necklace-type button switch, and switch signals were input and processed with general-purpose input/output. The first and second feasibility tests for the EMG switch and button switch were conducted in a total of three test sessions. The result of the feasibility test indicated that the major inconvenience and desired improvement associated with the EMG switch were the intricacy of the AAC device settings. The major inconveniences and desired improvements for the necklace-type button switch involved device shifting, volume and weight, and inconvenience in fixing the switch in various directions. Thus, based on the first and second feasibility tests, we developed an additional device. Finally, the EMG switch and necklace-type button switch developed to remedy the inconveniencies had high feasibility.

The Relationship Between Physiological Mechanisms and the Self-Perception of Vocal Effort

Purpose This study aimed to examine the relationship between a large set of hypothesized physiological measures of vocal effort and self-ratings of vocal effort. Method Twenty-six healthy adults modulated speech rate and vocal effort during repetitions of the utterance /ifi/, followed by self-perceptual ratings of vocal effort on a visual analog scale. Physiological measures included (a) intrinsic laryngeal tension via kinematic stiffness ratios determined from high-speed laryngoscopy, (b) extrinsic suprahyoid and infrahyoid laryngeal tension via normalized percent activations and durations derived from surface electromyography, (c) supraglottal compression via expert visual-perceptual ratings, and (d) subglottal pressure via magnitude of neck surface vibrations from an accelerometer signal. Results Individual statistical models revealed that all of the physiological predictors, except for kinematic stiffness ratios, were significantly predictive of self-ratings of vocal effort. However, a combined regression model analysis yielded only 3 significant predictors: subglottal pressure, mediolateral supraglottal compression, and the normalized percent activation of the suprahyoid muscles (adjusted R 2 = .60). Conclusions Vocal effort manifests as increases in specific laryngeal physiological measures. Further work is needed to examine these measures in combination with other contributing factors, as well as in speakers with dysphonia.

High-density surface electromyography: A visualization method of laryngeal muscle activity

OBJECTIVES/HYPOTHESIS

Laryngeal muscle activation is a complex and dynamic process. Current evaluation methods include needle and surface electromyography (sEMG). Limitations of needle electromyography include patient discomfort, interpretive complexity, and limited duration of recording. sEMG demonstrates interpretive challenges given loss of spatial selectivity. Application of high-density sEMG (HD sEMG) arrays were evaluated for potential to compensate for spatial selectivity loss while retaining benefits of noninvasive monitoring.

STUDY DESIGN

Basic science.

METHODS

Ten adults performed phonatory tasks while a 20-channel array recorded spatiotemporal data of the anterior neck. Data were processed to provide average spectral power of each electrode. Comparison was made between rest, low-, and high-pitch phonation. Two-dimensional (2D) spectral energy maps were created to evaluate use in gross identification of muscle location.

RESULTS

Three phonatory tasks yielded spectral power measures across the HD sEMG array. Each electrode within the array demonstrated unique power values across all subjects (P < .001). Comparison of each electrode to itself across phonatory tasks yielded differences in all subjects during rest versus low versus high, rest versus low, and rest versus high and in 9/10 subjects (P < .001) for low versus high phonation. Symmetry of HD sEMG signal was noted. Review of 2D coronal energy maps allowed for gross identification of cricothyroid muscle amidst anterior strap musculature.

CONCLUSIONS

HD sEMG can be used to identify differences in anterior neck muscle activity between rest, low-, and high-pitch phonation. HD sEMG of the anterior neck holds potential to enhance diagnostic and therapeutic monitoring for pathologies of laryngeal function.

LEVEL OF EVIDENCE

NA Laryngoscope, 129:2347-2353, 2019.

Swallowing changes related to chronic temporomandibular disorders

OBJECTIVES

To investigate whether chronic temporomandibular disorder (TMD) patients showed any changes in swallowing compared to a control group. Moreover, it was examined whether swallowing variables and a valid clinic measure of orofacial myofunctional status were associated.

MATERIAL AND METHODS

Twenty-three patients with chronic TMD, diagnosed with disc displacement with reduction (DDR) and pain, according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and 27 healthy volunteers (control group) were compared. Surface electromyography (EMG) of the temporalis, masseter, sternocleidomastoid, and suprahyoid muscles was performed during swallowing tasks of thin liquid (10 and 15 mL) and spontaneous saliva. Data were normalized.

RESULTS

Compared to the control group, TMD patients showed a prolonged duration of swallowing for liquid and saliva and required a longer time to reach the activity peak and half the integral. While the overall mean value of the relative peaks was similar for the groups, the suprahyoid peak was significantly lower in the TMD group during swallowing of liquid. Moreover, TMD patients recruited the jaw elevator muscles proportionally more than controls. The orofacial myofunctional status was moderately correlated with EMG parameters.

CONCLUSION

Patients with chronic TMD showed temporal prolongation and changes in the relative activity of the muscles during the swallowing tasks.

CLINICAL RELEVANCE

The present results contribute additional evidence regarding the reorganization of muscle activity in patients with chronic TMD.

Covert singing in anticipatory auditory imagery

To date, several fMRI studies reveal activation in motor planning areas during musical auditory imagery. We addressed whether such activations may give rise to peripheral motor activity, termed subvocalization or covert singing, using surface electromyography. Sensors placed on extrinsic laryngeal muscles, facial muscles, and a control site on the bicep measured muscle activity during auditory imagery that preceded singing, as well as during the completion of a visual imagery task. Greater activation was found in laryngeal and lip muscles for auditory than for visual imagery tasks, whereas no differences across tasks were found for other sensors. Furthermore, less accurate singers exhibited greater laryngeal activity during auditory imagery than did more accurate singers. This suggests that subvocalization may be used as a strategy to facilitate auditory imagery, which appears to be degraded in inaccurate singers. Taken together, these results suggest that subvocalization may play a role in anticipatory auditory imagery, and possibly as a way of supplementing motor associations with auditory imagery.

Position-independent gesture recognition using sEMG signals via canonical correlation analysis

Gesture recognition based on surface electromyogram (sEMG) signals has drawn significant attention and obtained satisfactory achievement in the field of human-computer interaction. However, the same gesture performed with different arm positions tends not to generate the same sEMG signals. Traditional solutions can be divided into two types. One type treats the same gesture with different arm positions as the same type, leading to a relatively low classification rate. The other type adopts a gesture classifier followed by the position classifier, which will achieve a satisfactory classification accuracy but at the expenses of high training burdens. To address these issues, we propose a novel framework to explore the intrinsic position independent (PI) characteristics of sEMG signals generated from the same gesture with different arm positions by canonical correlation analysis (CCA), termed as PICCA. In this framework, with the bridge link of the predefined expert set, both the training set and the testing set can be mapped into a unified-style with CCA, and hence, the classification accuracy can be improved in both user-dependent and user-independent manners. Experimental results on 13 gestures with 3 arm positions indicate that the proposed PICCA can achieve higher classification rates than those without CCA (with 28.52% and 44.19% promotions during user-dependent and user-independent manners respectively) while maintaining acceptable training burdens. These improvements will facilitate the practical implementation of myoelectric interfaces.