Identification of the most significant electrode positions in electromyographic evaluation of swallowing-related movements in humans

Advancements and Challenges in Non-Invasive Sensor Technologies for Swallowing Assessment: A Review

Dysphagia is a pervasive health issue that impacts diverse demographic groups worldwide, particularly the elderly, stroke survivors, and those suffering from neurological disorders. This condition poses substantial health risks, including malnutrition, respiratory complications, and increased mortality. Additionally, it exacerbates economic burdens by extending hospital stays and escalating healthcare costs. Given that this disorder is frequently underestimated in vulnerable populations, there is an urgent need for enhanced diagnostic and therapeutic strategies. Traditional diagnostic tools such as the videofluoroscopic swallowing study (VFSS) and flexible endoscopic evaluation of swallowing (FEES) require interpretation by clinical experts and may lead to complications. In contrast, non-invasive sensors offer a more comfortable and convenient approach for assessing swallowing function. This review systematically examines recent advancements in non-invasive swallowing function detection devices, focusing on the validation of the device designs and their implementation in clinical practice. Moreover, this review discusses the swallowing process and the associated biomechanics, providing a theoretical foundation for the technologies discussed. It is hoped that this comprehensive overview will facilitate a paradigm shift in swallowing assessments, steering the development of technologies towards more accessible and accurate diagnostic tools, thereby improving patient care and treatment outcomes.

Comparison of Submental Surface Electromyography during Dry Swallow between Irradiated Head and Neck Cancer Survivors and Normal Individuals

INTRODUCTION

This study compared the submental surface electromyography (sEMG) duration and amplitude during dry swallowing between irradiated head and neck cancer (HNC) survivors and age-matched normal individuals. Further, the relationship between submental and infrahyoid sEMG in the irradiated HNC group was explored.

METHOD

Forty participants (20 HNC survivors and 20 age-matched normal individuals) participated in this study. The HNC survivors had completed organ preservation cancer treatment (at least 1-month post-treatment). They were on a complete oral diet without enteral supplementation (FOIS score> 4). Submental and infrahyoid sEMG activity was calculated for three trials of saliva swallow for each participant using sEMG. The duration and amplitude parameters considered were: onset duration - duration from the onset of swallowing to the maximum amplitude, offset duration - duration from the maximum amplitude to the end of the swallowing activity, total duration, and maximum amplitude.

RESULTS

The study found that irradiated HNC survivors exhibited prolonged temporal measures, particularly in the offset duration, which suggested a delayed descent of the hyolaryngeal complex during swallowing. Additionally, the HNC group showed a positive correlation between submental and infrahyoid sEMG. Furthermore, it was observed that the rate of increase in the duration of submental sEMG during subsequent swallowing was greater in HNC survivors which could be due to reduced salivation.

CONCLUSION

Compared to age-matched normal individuals, irradiated HNC survivors manifest alterations in the submental muscle activities during dry swallowing as measured using sEMG. The temporal and amplitude changes are likely to have arisen as a consequence of postradiation changes.

Objective Assessment of the Repeated Botox Treatment to the Synkinesis of Facial Paralysis by the Integrated Electromyography

BACKGROUND

The widely used botox type A (BTX-A) is effective against synkinesis in facial palsy sequelae. Repeated injections are necessary and permanent improvements have been reported. We objectively evaluated the changes in synkinesis at >6 months after BTX-A injection, including changes over time with the number of administrations.

METHODS

In 48 patients who received multiple BTX-A injections, evaluation by the Sunnybrook Facial Grading System (FGS) and integrated electromyography (iEMG) was performed before treatment and at least 6 months after the first, second, and third BTX-A injection. The iEMG ratio on the affected and healthy sides was calculated for each mimetic muscle and mimic motion.

RESULTS

There was no significant difference in the FGS synkinesis score before treatment and after the third injection, although an improvement was observed. The iEMG ratio was significantly improved in the orbicularis oculi with open-mouth smile and lip pucker after the third dose compared to before treatment. The orbicularis oris showed a significant improvement when the eyelids were closed, while the platysma showed a significant improvement when the eyelids were closed and when the lip was pursed. Multiple regression analysis revealed that the orbicularis oculi and platysma had a greater effect on the iEMG ratio for the number of treatments than other factors.

CONCLUSIONS

Repeated BTX-A injections showed improvements in synkinesis for the orbicularis oculi, orbicularis oris, and platysma, even after >6 months, compared to before treatment.

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.

Detection of swallowing disorders with a multiple-channel surface electromyography sensor sheet

Background/purpose

A sensor sheet comprising multiple electromyography electrodes that can be used to measure a series of multiple muscle activities related to swallowing was recently developed. In this study, we aimed to evaluate its utility in detecting swallowing disorders with a new method for the identification of muscle activity.

Materials and methods

All participants were evaluated by using the repetitive saliva swallowing test and modified water swallowing test and were classified accordingly into participants with (n = 21; mean age, 81.6 [standard deviation, 10.1] years) and those without (n = 41; mean age, 70.0 [8.4] years) dysphagia. The sheet contains four pairs of electrodes, and surface electromyography (sEMG) was performed on the suprahyoid (position A: upper front of the suprahyoid muscles; position B: bottom rear of the suprahyoid muscles) and infrahyoid (position C: above the infrahyoid muscles; position D: beneath the infrahyoid muscles) muscles while the participants swallowed liquid, thickened water, paste, and jelly. The sEMG findings, including the duration of swallowing waveforms and the delay in swallowing onset from position A to positions B, C, and D, were compared between the groups.

Results

The duration of muscle activity differed between the groups in the infrahyoid muscles when jelly (Mann–Whitney U test; position C, P = 0.007 and position D, P = 0.018) and thickened water (position C, P = 0.033) were swallowed.

Conclusion

Our study demonstrates the utility of a novel sensor sheet developed for detecting swallowing disorders by using visual methods for identification of muscle activity.

Diagnosis and treatment of neurogenic dysphagia - S1 guideline of the German Society of Neurology

Introduction

Neurogenic dysphagia defines swallowing disorders caused by diseases of the central and peripheral nervous system, neuromuscular transmission, or muscles. Neurogenic dysphagia is one of the most common and at the same time most dangerous symptoms of many neurological diseases. Its most important sequelae include aspiration pneumonia, malnutrition and dehydration, and affected patients more often require long-term care and are exposed to an increased mortality. Based on a systematic pubmed research of related original papers, review articles, international guidelines and surveys about the diagnostics and treatment of neurogenic dysphagia, a consensus process was initiated, which included dysphagia experts from 27 medical societies.

Recommendations

This guideline consists of 53 recommendations covering in its first part the whole diagnostic spectrum from the dysphagia specific medical history, initial dysphagia screening and clinical assessment, to more refined instrumental procedures, such as flexible endoscopic evaluation of swallowing, the videofluoroscopic swallowing study and high-resolution manometry. In addition, specific clinical scenarios are captured, among others the management of patients with nasogastric and tracheotomy tubes. The second part of this guideline is dedicated to the treatment of neurogenic dysphagia. Apart from dietary interventions and behavioral swallowing treatment, interventions to improve oral hygiene, pharmacological treatment options, different modalities of neurostimulation as well as minimally invasive and surgical therapies are dealt with.

Conclusions

The diagnosis and treatment of neurogenic dysphagia is challenging and requires a joined effort of different medical professions. While the evidence supporting the implementation of dysphagia screening is rather convincing, further trials are needed to improve the quality of evidence for more refined methods of dysphagia diagnostics and, in particular, the different treatment options of neurogenic dysphagia. The present article is an abridged and translated version of the guideline recently published online (https://www.awmf.org/uploads/tx_szleitlinien/030-111l_Neurogene-Dysphagie_2020-05.pdf).

Detection of swallowing disorders using a multiple channel surface electromyography sheet: A preliminary study

Background/purpose

We invented a sensor sheet with multiple electromyogram electrodes, which can be easily attached to the front of the neck, to evaluate surface electromyograms (sEMG) during swallowing function. In this paper, we evaluated sEMG in healthy volunteers and dysphagia patients using the sensor sheet and discussed its potential to evaluate swallowing function.

Materials and methods

Ten healthy volunteers (age, 29.5 ± 3.9 years) and 18 clinically diagnosed dysphagia patients (age, 67.8 ± 12.1 years) were included. The sensor sheet had four pairs of electrodes, and sEMG at the suprahyoid muscles (positions A and B) and the infrahyoid muscles (positions C and D) were recorded while swallowing water, thickened water, yogurt, and jelly; sEMG findings were compared between these positions.

Results

Significant differences in the duration of muscle activity was observed when swallowing yogurt at position D and when swallowing jelly, thickened water, and water at position B (Mann–Whitney U test, p < 0.05). In healthy volunteers, muscle activation typically began from positions A or B to position D, whereas in dysphagia patients, it sometimes began from position D.

Conclusion

There were significant differences in duration and sequence patterns of four sEMG activities between healthy young volunteers and dysphagia patients in the assessment using the sensor sheet, although some technical and scientific problems remained unresolved. These results indicate that swallowing function could be evaluated using the sensor sheet.