Effortful Swallowing Training Coupled with Electrical Stimulation Leads to an Increase in Hyoid Elevation During Swallowing

Swallowing Rehabilitation: Tracing the Evolution of Assessment and Intervention Approaches for Dysphagia over 30 Years

Dysphagia or difficulty in swallowing is a common condition affecting millions worldwide. It can occur due to structural problems, neurological disorders, cancer treatment, aging, etc. Swallowing rehabilitation aims to help patients regain safe and efficient swallowing function through compensatory strategies and exercises. This literature review examines the recent advancements in swallowing rehabilitation techniques over the past three decades, with a focus on innovations in diagnostics, personalized medicine, and patient care.

Longitudinal Analysis of Swallowing Displacement Kinematics After Oropharyngeal Cancer Treatment

BACKGROUND/OBJECTIVE

Quantitative swallowing displacement kinematics evolve in patients treated for oropharyngeal squamous cell carcinoma (OPSCC). We aimed to longitudinally assess these measurements and correlate them with functional swallowing outcomes.

METHOD

A retrospective review was conducted on patients with OPSCC treated with definitive (chemo)radiation ([C]RT) or surgery with adjuvant (chemo)radiation (S-[C]RT) who completed at least two videofluoroscopic swallow studies (VFSS). Longitudinal analysis was accomplished via mixed-effects logistic regression for the Functional Oral Intake Scale (FOIS), and Penetration Aspiration Scale (PAS), and mixed-effects linear regression for kinematic measures. Spearman's correlation was conducted between changes in FOIS/PAS and kinematic measures.

RESULTS

Ninety-seven patients (76 males; mean age 61) completed 245 VFSS studies. A total of 94% had human papillomavirus (HPV)/p16 positive OPSCC and 74% were T0-T2. Sixty-four patients underwent [C]RT while 33 patients underwent S-[C]RT. After treatment, posterior pharyngeal wall at hold (PPWhold) increased 3.2 standard deviation (SD) between 0 and 6 months (p < 0.001), then decreased 2.2 SD between 6 and 12 months (p < 0.001) and did not return to baseline. Hyoid-to-larynx (HL) (p = 0.046) and maximal hyoid displacement (Hmax) + HL (p = 0.042) increased between 6 and 12 months. Hmax (p = 0.020) and Hmax + HL (p < 0.001) decreased between 12-24 months beyond baseline values. The decrease in HL and increase in PPWhold (p < 0.05) correlated with an increase in PAS. From baseline, increased pharyngeal constriction ratio correlated with decreased FOIS and PPWhold (p < 0.05).

CONCLUSIONS

Quantitative swallowing kinematic measures can effectively track changes in swallowing physiology. Increased PPWhold and restricted hyolaryngeal movement were seen in patients with OPSCC after treatment and correlated with a change in swallowing outcome, emphasizing the need for serial VFSS monitoring and targeted intervention.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Submental transcutaneous electrical stimulation can impact the timing of laryngeal vestibule closure

Background

Laryngeal vestibule closure (LVC) is one of the critical airway protection mechanisms during swallowing. LVC timing impairments during swallowing are among the common causes of airway invasion in patients with dysphagia.

Objectives

To understand whether using submental transcutaneous electrical stimulation (TES) with varying pulse durations can impact the LVC reaction time (LVCrt) and LVC duration (LVCd) measures in healthy adults.

Methods

Twenty‐six healthy adults underwent three TES conditions while receiving three trials of 10 ml pureed: no TES, TES with short pulse duration (300 μs) and TES with long pulse durations(700 μs). Two pairs of electrodes were placed diagonally on the submental area. For each active TES condition, the stimulation was increased up to the participant's self‐identified maximum tolerance. Each swallow trial was recorded using videofluoroscopic swallowing study. All data were extracted and analysed offline using VideoPad Video Editor program.

Results

Submental TES reduced LVCrt during swallowing [F (2, 46) = 7.234, p < .007, ηp2 = .239] but had no significant impact on LVCd [F (2, 50) = .1.118, p < .335, ηp2 = .043]. Furthermore, pulse duration had no distinguished impact on any LVC timing measures.

Conclusion

Transcutaneous electrical stimulation may benefit patients with dysphagia who suffer from delayed LVC during swallowing. Future studies should seek whether the same physiologic effect can be observed in patients with dysphagia.

Transcutaneous Electrical Stimulation as a Resistance Force in Lingual Exercise: A Preliminary Proof-of-Concept Study

BACKGROUND

Limited knowledge exists regarding whether transcutaneous electrical stimulation (TES) based exercise can improve the lingual pressure generation.

OBJECTIVES

To compare the effect of submental TES with two different pulse durations (PD) coupled with isometric lingual exercises on lingual pressure measures.

METHODS

Twenty-eight healthy volunteers were divided into two submental TES groups: short PD (300 μs) and long PD (700 μs). The Iowa Oral Performance Instrument (IOPI) was used for lingual pressure measurements and exercise. In total, participants attended six exercise sessions three days per week for two consecutive weeks. Maximum and swallowing lingual pressures were measured one hour following each exercise session and three days after the final session to assess any detraining effect. Data were analyzed using repeated measure ANOVA.

RESULTS

Mean maximum lingual pressure change was significantly greater in TES with short PD versus the long PD condition following the first week of exercise. Following the two-week exercise, a significant increase was found in mean maximum lingual pressure for short and long PD conditions compared with the baseline. However, no significant difference was found between PD conditions for maximum lingual pressure. Likewise, no significant differences in swallowing lingual pressure were found compared with the baseline or across the two TES conditions.

CONCLUSION

Although short PD induced greater gain in maximum lingual pressure than the long PD after week 1, the enhanced effect faded after week 2, leading to a comparable increase in maximum lingual pressure for both groups. However, increased gain in maximum lingual pressure was not transferred to lingual pressure during swallowing.

Transcutaneous electrical nerve stimulation in speech therapy rehabilitation of voice and swallowing function in adults-a systematic review

INTRODUCTION

In recent years, a number of clinical trials have been published comparing transcutaneous electrical nerve stimulation (TENS) and traditional speech therapy treatment of voice and swallowing functions, but results have been conflicting.

OBJECTIVE

Assess the methodological quality of studies and determine whether TENS is an efficient therapeutic strategy for speech therapy treatment of healthy adults or those with dysphonia and/or dysphagia.

METHODS

The databases used were Medical Literature Analysis and Retrieval System Online (MedLine), Biblioteca Virtual em Saúde (BVS), Cochrane Library and Web of Science (ISI Web of Knowledge). The study was conducted between May 2018 and January 2019, in line with Cochrane Handbook guidelines, and included studies on the use of TENS in healthy adults or those with compromised voice and/or swallowing function.

RESULTS

After the search and extraction of studies, the following were identified: TENS + VOICE: 7 articles; TENS + SWALLOWING: 5 articles. The studies exhibited medium quality and are heterogeneous, making it difficult to determine their effectiveness and the parameters to be used in future research. There were no statistically significant differences between the use of TENS alone or associated with another therapeutic technique for voice. For swallowing function, one study proved better results in cases of associated techniques - TENS + traditional therapy.

DISCUSSION

Speech therapy should increase the number of studies published and improve their methodological quality, reassessing methodological criteria. Current clinical practice is not grounded in evidence-based science. CLINICAL MESSAGE: the studies analyzed exhibited medium methodological quality; there are variations in the time, number and periodicity of the therapeutic sessions for TENS; there were no statistically significant differences between the use of TENS alone or associated with another therapeutic technique in voice; there were statistically significant differences between the use of TENS associated with traditional therapeutic in swallowing function.

Assessment of Changes in Laryngeal Configuration and Voice Parameters Among Different Frequencies of Neuromuscular Electrical Stimulation (NMES) and Cumulative Effects of NMES in a Normophonic Subject: A Pilot Study

INTRODUCTION

Neuromuscular electrical stimulation (NMES) is a complementary resource to voice therapy that can be used for the treatment of hypofunctional voice disorders. Although positive clinical studies have been reported, neutral and even potentially harmful effects of NMES are also described in the literature. Furthermore, in the studies examined by the authors, the use of different methods of NMES have been identified, which further contributes to the inconsistent results found among studies. Moreover, limited rationale is provided for the chosen NMES parameters such as electrode placement, frequency of NMES and length of treatment. The aims of this pilot study were to investigate the a) impact of different frequencies of NMES on glottal configuration and vocal fold vibration patterns and b) changes in laryngeal configuration and vocal output across 12 minutes of NMES.

METHOD

Three experiments were carried out looking at changes in laryngeal configuration and voice output using different imaging techniques (fibreoptic nasolaryngoscopy and high-speed video), acoustical analysis (F0, formant analysis, SPL, CPPS and LHSR values), electroglottography (EGG) and Relative Fundamental Frequency (RFF) analyses. Glottal parameters and acoustical measures were recorded before, during, and after stimulation. Data was collected at rest and during phonation.

RESULTS

Overall the results showed global changes in laryngeal configuration from normal to hyperfunctional (ie, increased RFF, SPL, CQ, and stiffness). Changes were more pronounced for lower frequencies of NMES and were significant within less than three minutes of application.

CONCLUSION

NMES is an effective resource for the activation of intrinsic laryngeal muscles producing significant levels of adduction within few minutes of application. Lower NMES frequencies produced greater muscle activation when compared to higher frequencies.

Effects of Synchronized Neuromuscular Electrical Stimulation (NMES) on the Submental Muscles During Ingestion of a Specified Volume of Soft Food in Patients with Mild-to-Moderate Dysphagia Following Stroke

Background

Neuromuscular electrical stimulation (NMES) is a method for producing regular contractions of muscles that have been paralyzed. This study aimed to evaluate the effects of synchronized NMES on the submental muscles during ingestion of a specified volume of soft food in patients with mild-to-moderate dysphagia following stroke.

Material/Methods

Eighty-three patients with mild-to-moderate dysphagia following stroke were enrolled and randomly divided into 3 groups: conventional training (CT) (n=28), eating training (ET) (n=28), and intensive swallowing training (IST) (n=27). The CT group received conventional swallow training, the ET group was given additional individual feedings with a specified volume of soft food, and the IST group received intensive swallowing training with synchronized NEMS. All of the patients were evaluated before and after the treatment with a modified barium swallow, and the Dysphagia Outcome and Severity Scale (DOSS); the numbers of patients with Stroke-Associated Pneumonia (SAP) and wet voice also were assessed.

Results

After 6 weeks, DOSS scores improved in patients in all 3 groups, and there were significant differences among the groups in their scores (P<0.001 for both measures). In the CT and ET groups, there was a statistically significant difference in the number of patients with SAP before and after treatment (P=0.010 and P<0.001, respectively). There also were fewer cases in the IST group than in the CT (P=0.042) and ET groups (P=0.011). After completion of treatment, compared with the first treatment, there were significantly fewer patients with wet voices in the CT (P<0.001) and IST groups (P<0.001).

Conclusions

Feeding a specified volume of soft food plus synchronized NMES of the submental muscles can improve the swallowing function of patients with mild-to-moderate dysphagia following stroke and it reduces their risk of food aspiration.

Effects of Varying Transcutaneous Electrical Stimulation Pulse Duration on Swallowing Kinematics in Healthy Adults

Prior research in swallowing physiology has suggested that using submental transcutaneous electrical stimulation (TES) with short pulse duration (PD) (300 μs) may enhance the impact on deep extrinsic tongue muscles, thereby pulling the tongue down during swallowing. However, it was unclear whether that same TES protocol could have a differential impact on hyolaryngeal kinematics and timing. This study aimed to compare the effect of submental TES with varying PDs on anterior and superior hyolaryngeal kinematics and timing both at rest and during swallowing in healthy adults. Twenty-four healthy adults between the ages of 22 and 77 participated in this study. Anterior and superior hyolaryngeal excursion magnitude and duration measures were collected using videofluoroscopic swallowing study. Each subject swallowed three 10 ml pudding trials under three conditions: no TES, TES with short PD (300 μs), and TES with long PD (700 μs). TES was delivered using two-channel surface electrodes in the submental area. In both short and long PD conditions, TES amplitude was gradually increased until participants reached their maximum tolerance level. Videofluoroscopic data were analyzed using VideoPad Video Editor and Image J programs. One-way repeated measure ANOVAs were conducted to identify within-subject effect of TES condition. For hyoid movement, TES with short PD selectively placed the hyoid bone on a more anterior position at rest and reduced anterior hyoid excursion during swallowing compared with the no TES condition. Regarding laryngeal movement, both TES protocols resulted in the larynx taking on a more anterior position at rest and reduced anterior laryngeal excursions during swallowing when compared with the no TES condition. Varying PDs had no significant effect on the superior hyoid and laryngeal movements at rest and during swallowing. Both TES protocols induced shorter hyoid elevation duration during swallowing Findings suggest that though both TES protocols demonstrated a comparable impact on reducing anterior laryngeal excursions, the TES protocol with short PD had an enhanced effect on reducing anterior hyoid excursion during swallowing. This reduced range of motion may result from stimulating the deep submental muscles, which primarily place the hyoid and larynx into a more forward position before swallowing onset. Overall, the TES protocol with short PD may have an increased benefit in facilitating swallowing in patients with dysphagia.

Effects of Effortful Swallowing Exercise with Progressive Anterior Tongue Press Using Iowa Oral Performance Instrument (IOPI) on the Strength of Swallowing-Related Muscles in the Elderly: A Preliminary Study

The purpose of this study was to confirm the effect of effortful swallowing (ES) exercise programs applied to increase the swallowing-related muscle strength in the elderly. In this study, 20 healthy elderly people (76.65 ± 5.87 years; 10 women and 10 men) participated and exercised for 7 weeks. The experimental group performed ES exercise combined with external resistance using Iowa Oral Performance Instrument (IOPI), and the control group performed pure ES without external resistance. The exercises were performed for 20 min a day, 2 days a week for 7 weeks in both groups. ES was repeated 60 times in weeks 1 and 2, 80 times in week 3 and 4, and 120 times in weeks 5-7. In the experimental group, the isometric and swallowing tongue pressures at week 8 were significantly improved compared to baseline. At week 8, the anterior and swallowing tongue pressures and anterior tongue endurance were significantly higher than those of the control group. In the control group, no significant change in tongue pressure-related variables was observed after 7 weeks of exercise. ES exercise combined with IOPI resistance for 7 weeks tended to increase the suprahyoid muscle activation level without statistical significance. For clinical application of this exercise protocol, further studies including more elderly people and patients with dysphagia are required.

Systematic Effortful Swallowing Exercise Without External Resistance Does Not Increase Swallowing-Related Muscle Strength in the Elderly

Effortful swallow (ES) is a maneuver intended to increase pressure on a bolus by swallowing and pushing with sufficient force to facilitate clearance. Although ES is mainly known for its immediate effects, the long-term effects of applying ES as an exercise program remain unclear. This study investigated the effects of a 7-week systematic ES exercise regime on swallowing-related muscle strength in individuals aged 65 years and over. In total, 30 healthy older adults participated in this study (16 women and 14 men, aged 67-90 years). The subjects participated in the exercise program for 20 min a day, twice a week, for 7 weeks. To gradually increase exercise intensity, the number of exercises per session was increased from the initial 60 repetitions (weeks 1-2) to 120 repetitions (weeks 5-7). To measure the effect of the strengthening exercise program, the activation level of suprahyoid muscles was measured using surface electromyography, and a tongue pressure measurement system was used to measure variables related to tongue strength (isometric tongue pressure, swallowing tongue pressure, and tongue endurance). Although the effect of ES exercise on muscle strength through gradual adjustment of exercise frequency was not confirmed, ES remains valuable as an exercise for strengthening the muscles involved in swallowing. Future studies are warranted to determine the effects of ES exercise after adjusting for other variables of exercise intensity.

Transcutaneous Electrical Stimulation and Dysphagia Rehabilitation: A Narrative Review

Transcutaneous electrical stimulation (TES) was introduced as a modality for dysphagia rehabilitation more than a decade ago. The underlying premise of this modality is improving the structural movements and enhancing neural activation based on stimulation-induced muscle contractions. However, divisive evidence exists regarding the effectiveness of this treatment modality. This manuscript reviews current evidence regarding the effects of transcutaneous electrical stimulation (TES) on clinical and physiological aspects of swallowing function. Furthermore, this narrative review delineates the knowledge gap in this area and recommends future research roadmap. This review gives a comprehensive picture regarding current knowledge of TES to practicing speech and language pathologists and interested researchers. It highlights the need for more robust studies in this area. It also encourages researchers to focus more on the physiologic studies to understand the physiologic underpinning behind this treatment modality.

A Novel Method Using Kinesiology Taping for the Activation of Suprahyoid Muscles in Healthy Adults: A Preliminary Research

The suprahyoid muscles play a major role in safe swallowing in the pharyngeal phase. Therefore, it is clinically important to design a therapeutic approach for strengthening the suprahyoid muscles for safe and normal swallowing. This study aimed to investigate the activation of suprahyoid muscles by resistance training using kinesiology taping (KT). We enrolled 23 healthy adults. All participants performed saliva swallowing five times at 5 s intervals in three conditions (without KT, 50% stretch with KT, and 80% stretch with KT). KT in the I and reverse V shapes was pulled vertically from the hyolaryngeal complex to the sternum and medially from the superior surface of the clavicle, respectively. Another KT horizontally covered the hyolaryngeal complex to enhance the movement restriction of the hyolaryngeal complex during swallowing. Activation of the suprahyoid muscles during swallowing in the two conditions was measured using surface electromyography. In addition, a 0-10 numerical rating self-report scale was used to evaluate the required effort and the resistance felt during swallowing. Both KT 50% and 80% were significantly higher in surface electromyography (sEMG) mean value, peak value, required effort, and resistance felt during swallowing compared to normal swallowing (p < 0.05). In addition, KT 80% was significantly higher in sEMG value, peak value, required effort, and resistance felt during swallowing than KT 50% (p < 0.05). This study demonstrated that KT applied to the area under the hyolaryngeal complex improves activation of the suprahyoid muscle during swallowing. Therefore, KT applied as resistance during swallowing is considered to have therapeutic potential in dysphagia rehabilitation.

Swallowing Disorders in the Older Population

Swallowing problems, or dysphagia, are common as people age, and are associated with significant negative outcomes, including weight loss, pneumonia, dehydration, shortened life expectancy, reduced quality of life, and increased caregiver burden. In this article, we will discuss the complex process of swallowing in normal circumstances and with healthy aging, then review etiologies that contribute to dysphagia. We will discuss approaches to evaluating and treating dysphagia, providing relevant data where they are available. We highlight the desperate need for high-quality research to guide best practices in treating dysphagia in older adults. J Am Geriatr Soc 67:2643-2649, 2019.

Effects of the head lift exercise and neuromuscular electrical stimulation on swallowing muscles activity in healthy older adults: a randomized pilot study

PURPOSE

Swallowing physiology exhibits several changes in advanced ages. The present study aimed to investigate and compare effects of a period of the head lift exercise (HLE) and neuromuscular electrical stimulation (NMES) on swallowing muscles activity in healthy elderly.

PATIENTS AND METHODS

A total of 23 older adults were randomized to either the HLE or NMES group for ten therapy sessions. They received pre- and post-therapy surface electromyography (sEMG) during water swallowing.

RESULTS

For the HLE group, duration of suprahyoid muscles activity was significantly reduced at post-intervention compared to pre-intervention (p=0.036). Moreover after treatments, duration and latency between onset and peak amplitude of suprahyoid muscles activity was significantly shorter in the HLE group compare to the NMES group (respectively, p=0.007 and p=0.003).

CONCLUSION

Our findings suggest that the HLE, against the NMES, may be effective in reducing some aging effects on the suprahyoid muscles activity, especially in elders who demonstrate prolonged duration and latency between onset and peak of the suprahyoid muscles activity during swallowing.

Effects of Neuromuscular Electrical Stimulation for Masseter Muscle on Oral Dysfunction After Stroke

Objective

To determine positive effect of neuromuscular electrical stimulation (NMES) in conventional dysphagia therapy on masseter muscle oral dysfunction of patients after subacute stroke.

Methods

Among subacute stroke patients who were diagnosed as oropharyngeal dysphagia by videofluoroscopy swallowing study (VFSS), those with oral dysfunction were enrolled. They were randomly assigned to a study group or a control group. The study group received NMES on masseter muscle and suprahyoid muscle simultaneously, while the control group received NMES only on suprahyoid muscle. NMES therapy session as applied 30 minutes each time, two times per day for a total of 20 sessions. Both groups received conventional dysphagia therapy for 2 weeks. All enrolled patients were evaluated by VFSS after 2 weeks. Oropharyngeal swallowing function was evaluated by Penetration-Aspiration Scale, Functional Dysphagia Scale (FDS), and American Speech-Language-Hearing Association National Outcome Measurement System swallowing scale based on results of VFSS.

Results

Patients were randomly assigned to the study group (n=20) or the control group (n=20). There were no significant differences in baseline characteristics or initial values between the two groups. After 2 weeks of NMES, both groups showed improvement in scores of total FDS and pharyngeal phase FDS. Additionally, the study group showed improvement in oral phase FDS. Changes in all measurements were similar between the two groups.

Conclusion

In this preliminary study, NMES for masseter muscle has a therapeutic effect on oral dysfunction of patients after subacute stroke.

The Effects of Electrical Stimulation Pulse Duration on Lingual Palatal Pressure Measures During Swallowing in Healthy Older Adults

Limited research in swallowing physiology has suggested that the most common existing transcutaneous electrical stimulation (TES) protocol (VitalStim) may not penetrate to layers of tissue to affect deep swallowing muscles. TES amplitude is the primary parameter that determines the depth of electrical current penetration (DECP). Preliminary work suggests that replacing a long-pulse duration with a short-pulse duration can increase maximum amplitude tolerance (MAT) within subjects' comfort level. Increasing MAT may indicate a higher DECP. The current study evaluates this premise in reference to the effects of varying pulse duration on lingual-palatal pressure during swallowing. Thirty healthy older adults (60-70 years of age) participated in this study. Each subject swallowed three trials of 10 mL pudding under three TES conditions: no stimulation, short-pulse duration, and long-pulse duration. TES was delivered using two pairs of surface electrodes on the submental muscles. MAT and perceived discomfort levels were identified separately for short and long-pulse TES conditions. Lingual-palatal peak pressure, pressure integral, and pressure duration were measured under each condition. Two-way repeated measures ANOVAs were conducted to identify within subject effects of TES condition and tongue bulb location. Lingual-palatal pressure and pressure integral were significantly reduced in the short-pulse duration condition. MAT was significantly higher in the short-pulse duration versus the long-pulse duration condition. Furthermore, MAT was significantly correlated with lingual-palatal pressure. Changing pulse duration had no significant impact on tongue pressure duration. Results suggest that a short-pulse duration may penetrate deeper into muscles involved in swallowing. The specific impact is reflected in a reduced upward pressure of the tongue on the palate during swallowing. This 'restrictive' effect of TES on tongue pressure may have the potential to be used during a resistive exercise paradigm for tongue elevation during swallowing.

Effect of electro-acupuncture on regulating the swallowing by activating the interneuron in ventrolateral medulla (VLM)

Ventrolateral medulla(VLM) was one of the essential part of central pattern generator(CPG) in swallowing and electro-acupuncture(EA) was an important intervention in swallowing disorder. But the effect and mechanism of EA at acupoints on swallowing were unknown. The present aim to detect the effect of EA at Lianquan (CV23) on swallowing and swallowing-related(SR) interneuron in VLM. Thirty-six Sprague-Dawley rats were operated and the swallowing reflex was induced through Double distilled water (DDW) infusion. Simultaneously, the numbers of swallowing were recorded. Then EA was given at Lianquan and Neiguan (PC6) and the neuron discharges in VLM were detected. A total of 72 neurons were recorded, 60 of which were correctly recorded after histology identification. Two types of SR neurons were found and the numbers of swallowing increased after EA at CV23 and PC6 compared with no EA group. The neuron response rates were 78.3% and 50% for EA at CV23 and PC6 respectively with significant difference (P < 0.05). Meanwhile, the neuron spike patterns were changed after EA at CV23 and PC6. In addition, twenty-four rats were used for immunofluorescence after EA at CV23 and PC6. The results showed that c-fos positive cells in CV23 group were 20.63±2.35, while PC6 group was 14.13±1.78 and 6.88±1.42 in control group. There were significant difference between them (P < 0.05). These results indicated that EA could regulate the swallowing function via activating the SR interneurons in VLM under the physiological condition.

Effects of Submental Surface Electrical Stimulation on Swallowing Kinematics in Healthy Adults: An Error-Based Learning Paradigm

PURPOSE

Hyoid bone and laryngeal approximation aid airway protection (laryngeal vestibule closure) while moving toward their peak superior and anterior positions during swallowing. Submental surface electrical stimulation (SES) is a therapeutic technique that targets the muscles that move the hyoid bone during swallowing. It is unknown whether submental SES only increases peak hyoid bone swallowing positions but not peak laryngeal swallowing positions, which could require faster or greater laryngeal movement to achieve adequate laryngeal vestibule closure.

METHOD

We examined the effects of submental SES on hyo-laryngeal kinematics in 30 healthy adults who swallowed 50 times using an error-based learning paradigm.

RESULTS

Submental SES did not alter any hyo-laryngeal swallowing kinematic. However, submental SES significantly changed the starting position of the hyoid bone just prior to the swallow onset (more anterior; p = .003). On average, submental SES immediately prior to swallow onset can position the hyoid approximately 20% closer to its peak swallowing point.

CONCLUSIONS

These findings indicate that electrical stimulation of the agonists for hyoid movement might not alter swallowing outcomes tested in this study. However, submental SES could have clinical utility by minimizing swallowing impairments related to reduced hyoid swallowing range of motion in individuals with dysphagia.

The effect of surface neuromuscular electrical stimulation on patients with post-stroke dysphagia

OBJECTIVE

To assess whether the clinical efficacy of a therapeutic protocol using surface neuromuscular electrical stimulation (sNMES) on patients with post-stroke dysphagia (PSD) is superior to that without sNMES, and whether swallowing functional outcome is different with regards to different electrode placement on patients' skin of neck.

METHODS

Thirty patients with PSD were randomly allocated into treatment group A (TGA), treatment group B (TGB) and control group according to a random number table. The three groups of patients all received traditional dysphagia therapy (TDT) and other general rehabilitation therapy such as physical therapy and occupational therapy as a basic treatment project. Besides this, sNMES treatment was applied on different sites of patients' neck skin in group A and B separately. All the patients received video-fluoroscopic swallowing study (VFSS) pre-treatment and 2 weeks post-treatment, during which the displacement of the hyolaryngeal complex towards the superior and anterior sides while swallowing semi-liquid diet were measured. Outcome of the VFSS was measured using dysphagia outcome and severity scale (DOSS).

RESULTS

Post-treatment evaluation was carried out using water swallow test (WST), repetitive saliva swallowing test (RSST) and dysphagia outcome and severity scale (DOSS) from the three study groups were all improved (P< 0.05). The results of post-treatment evaluation using WST from TGA and TGB were 2.40 ± 1.26 and 2.10 ± 0.99 respectively, using RSST from TGA and TGB were 5.30 ± 1.89 and 5.20 ± 1.69 respectively, using DOSS from TGA and TGB were 5.20 ± 1.40 and 5.10 ± 1.45 respectively. Compared to control group, the results of post-treatment evaluation using the three scales, there were significant improvement between TGA and TGB (P< 0.05), however, the inter-group differences of TGA and TGB indicated no statistically significant difference (P> 0.05). The post-treatment evaluation of the moving distance of hyoid bone towards anterior side in swallowing was significantly improved as compared to TGB (-8.40 ± 7.48, t=-3.552, P= 0.006), and was statistically significant as compared to the control group (P> 0.05).

CONCLUSIONS

Swallowing function in the patients with PSD was significantly improved using TDT combined with NMES. Stimulating electrodes placed at the suprahyoid region or on both suprahyoid and infrahyoid regions resulted in no difference of effect. However, NMES on suprahyoid region could further improve the moving distance of hyoid bone anteriorly.

O efeito da eletroestimulação neuromuscular na contração da musculatura supra-hióidea durante a deglutição de indivíduos com disfagia

RESUMO Objetivo: verificar o efeito da Eletroestimulação Neuromuscular na contração da musculatura supra-hióidea durante a deglutição em indivíduos pós-Acidente Vascular Cerebral com disfagia orofaríngea. Métodos: participaram da pesquisa oito indivíduos pós-Acidente Vascular Cerebral com disfagia, de ambos os sexos, encaminhados para terapia fonoaudiológica com objetivo de trabalhar a função da deglutição, em início de processo terapêutico. Anteriormente ao início da primeira sessão, foi realizada a mensuração do tempo e amplitude da atividade elétrica muscular através da Eletromiografia de Superfície de Biofeedback. Os pacientes foram divididos aleatoriamente em dois grupos: Grupo Experimental (n=4): pacientes que receberam a fonoterapia tradicional e aplicação da Eletroestimulação Neuromuscular; Grupo Controle (n=4): pacientes que receberam a fonoterapia tradicional. Após oito sessões, todos os pacientes passaram novamente pela Eletromiografia de Superfície de Biofeedback para verificar a atividade elétrica da musculatura supra-hióidea. Os registros dos exames pré e pós intervenção foram comparados nos dois grupos. Resultados: comparando-se as médias das variáveis de amplitude e tempo da atividade elétrica muscular durante a deglutição de saliva e nas duas deglutições de pastoso, não foram observadas diferenças estatisticamente significantes entre os grupos estudados, na comparação dos valores pré e pós intervenção. Conclusões: o uso da Eletroestimulação Neuromuscular nos parâmetros e na metodologia empregada não mostrou-se eficiente em promover maior contração da musculatura supra-hióidea durante a deglutição em indivíduos pós-Acidente Vascular Cerebral com disfagia orofaríngea. Os dados encontrados podem ser decorrentes da metodologia utilizada nesta pesquisa com relação ao protocolo de aplicação da técnica e à forma de mensuração dos resultados.

Neuromuscular Electrical Stimulation for Treatment-Refractory Chronic Dysphagia in Tube-Fed Patients: A Prospective Case Series

OBJECTIVE

The aim of this study was to evaluate the role of neuromuscular electrical stimulation (NMES) in tube-fed patients with severe and chronic dysphagia refractory to traditional swallowing therapy (TT).

PATIENTS AND METHODS

A total of 11 consecutive dysphagic patients with tube-dependent nutrition and who had not responded to 6 months of TT were enrolled. Each patient received NMES for 30 min and TT for 30 min, twice a day, 5 days per week for 4 weeks. In order to evaluate the swallowing impairment, each patient underwent a fiberoptic endoscopic examination of swallowing immediately before the beginning of the treatment, after 2 weeks and after 4 weeks.

RESULTS

All enrolled patients managed to complete the swallowing treatment protocol for at least 2 weeks. After the 4-week treatment, 6 of 11 enrolled patients passed to a total oral diet with single or multiple consistencies despite specific food limitations or special preparation or compensation. Five patients, all affected by the most severe form of dysphagia, maintained tube-dependent nutrition.

CONCLUSION

NMES as adjunctive treatment to TT may offer a new possibility for the management of tube-fed patients who are refractory to TT.

A Pilot Study of the Tongue Pull-Back Exercise for Improving Tongue-Base Retraction and Two Novel Methods to Add Resistance to the Tongue Pull-Back

This pilot study investigated the tongue pull-back (TPB) exercise to improve tongue-base retraction as well as two methods to add resistance to the TPB. Surface electromyography (sEMG) to the submental triangle was used as an indication of tongue-base activity on 13 healthy adults during: (1) saliva swallow, (2) 15 mL water swallow, (3) effortful swallow, (4) unassisted TPB, (5) TPB with added resistance by holding the tongue with gauze (finger-resisted TPB), and (6) TPB with the tongue clipped to a spring-loaded tension resistance device (device-resisted TPB). Order of the exercises was randomized. The exercises fell into two groups-weak and intense. Weak exercises included saliva swallow, water swallow, and unassisted TPB (mean sEMG = 19.07 μV, p = .593). Intense exercises included effortful swallow, finger-resisted TPB, and device-resisted TPB (mean sEMG = 36.44 μV, p = .315). Each intense exercise resulted in significantly higher mean sEMG peak amplitude than each weak exercise (p < .05), with one exception; the effortful swallow was not significantly different than the unassisted TPB (p = .171). This study provides preliminary evidence that the unassisted TPB may not be any more helpful for improving tongue-base retraction than normal swallowing. Adding resistance to the TPB by holding the tongue with gauze may be an effective alternative. This study also demonstrates proof-of-concept for creating a device to attach to the tongue and provide tension resistance during the TPB exercise. Further research with a more sophisticated design is needed before such a device can be fully developed and implemented clinically.

Uso da eletroestimulação na clínica fonoaudiológica: uma revisão integrativa da literatura

Resumo: Este trabalho tem como objetivo apresentar revisão integrativa de literatura sobre a aplicabilidade e o resultado do uso da eletroestimulação na prática clínica fonoaudiológica. Foram seguidos os preceitos do Cochrane Handbook, que envolveu a formulação da questão a ser investigada, localização e seleção dos estudos e avaliação crítica dos artigos. Foram utilizadas as bases de dados Medical Literature Analysis and Retrieval Sistem on-line (Medline), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), PubMed e Web of Science/ISI. Os descritores utilizados foram: "estimulação elétrica nervosa transcutânea", "estimulação elétrica", "disfagia", "transtornos de deglutição", "disfonia", "distúrbios da voz", "treinamento da voz" e "terapia por estimulação elétrica" em inglês, português e espanhol e suas combinações, no período entre 2003 e 2013. Os estudos analisados demonstraram que a eletroestimulação traz benefícios na reabilitação de pacientes na clínica fonoaudiológica, mas a metodologia utilizada nos estudos foi divergente e a população estudada muito heterogênea o que dificulta sua utilização clínica pelos profissionais da área. A eletroestimulação traz benefícios na reabilitação fonoaudiológica, porém novos estudos devem ser realizados utilizando uma amostra mais homogênea e descrevendo metodologia e técnicas fonoaudiológicas utilizadas nos procedimentos, a fim de comprovar seus resultados e viabilizar seu uso pelos profissionais da área.

Different Movement of Hyolaryngeal Structures by Various Application of Electrical Stimulation in Normal Individuals

Objective

To identify the differences in the movement of the hyoid bone and the vocal cord with and without electrical stimulation in normal subjects.

Methods

Two-dimensional motion analysis using a videofluoroscopic swallowing study with and without electrical stimulation was performed. Surface electrical stimulation was applied during swallowing using electrodes placed at three different locations on each subject. All subjects were analyzed three times using the following electrode placements: with one pair of electrodes on the suprahyoid muscles and a second pair on the infrahyoid muscles (SI); with placement of the electrode pairs on only the infrahyoid muscles (IO); and with the electrode pairs placed vertically on the suprahyoid and infrahyoid muscles (SIV).

Results

The main outcomes of this study demonstrated an initial downward displacement as well as different movements of the hyoid bone with the three electrode placements used for electrical stimulation. The initial positions of the hyoid bone with the SI and IO placements resulted in an inferior and anterior displaced position. During swallowing, the hyoid bone moved in a more superior and less anterior direction, resulting in almost the same peak position compared with no electrical stimulation.

Conclusion

These results demonstrate that electrical stimulation caused an initial depression of the hyoid bone, which had nearly the same peak position during swallowing. Electrical stimulation during swallowing was not dependent on the position of the electrode on the neck, such as on the infrahyoid or on both the suprahyoid and infrahyoid muscles.

Changes in hyolaryngeal movement and swallowing function after neuromuscular electrical stimulation in patients with Dysphagia

OBJECTIVE

To investigate immediate changes in hyolaryngeal movement and swallowing function after a cycle of neuromuscular electrical stimulation (NMES) on both submental and throat regions and submental placement alone in patients with dysphagia.

METHODS

Fifteen patients with dysphagia were recruited. First, videofluoroscopic swallowing study (VFSS) was performed before NMES. All patients thereafter received a cycle of NMES by 2 methods of electrode placement: 1) both submental and throat regions and 2) submental placement alone concomitant with VFSS. The Penetration-Aspiration Score (PAS) and the NIH-Swallowing Safety Scale (NIH-SSS) were measured for swallowing function.

RESULTS

During swallowing, hyolaryngeal descent significantly occurred by NMES on both submental and throat regions, and anterior displacement of hyolaryngeal complex was significant on submental placement alone. NMES on submental placement alone did not change the PAS and NIH-SSS. However, NMES on both submental and throat regions significantly reduced the NIH-SSS, although it did not change the PAS. Patients with no brainstem lesion and with dysphagia duration of <3 months showed significantly improved the NIH-SSS.

CONCLUSION

Immediate hyolaryngeal movement was paradoxically depressed after NMES on both submental and throat regions with significant reductions in the NIH-SSS but not the PAS, suggesting improvement in pharyngeal peristalsis and cricopharyngeal functions at the esophageal entry rather than decreased aspiration and penetration. The results also suggested that patients with dysphagia should be carefully screened when determining motor-level NMES.

Electrical neuromuscular stimulation in dysphagia: current status

PURPOSE OF REVIEW

To assess current information regarding the physiological effects of transcutaneous electrical stimulation (TES) on the neck and current evidence regarding the clinical effects of adding TES to dysphagia rehabilitation.

RECENT FINDINGS

Physiological studies have demonstrated that when electrical stimulation is applied on the throat it will lower the hyo-laryngeal complex and resist elevation needed for airway protection during swallowing. Submental TES has not been found to effectively elevate the hyo-laryngeal complex. Recent controlled clinical trials have had mixed results. Most indicate that TES is beneficial in the treatment of dysphagia; however, studies differ on whether these effects are greater than, equal to, or less than traditional therapy alone for the rehabilitation of swallowing.

SUMMARY

Currently TES for dysphagia is one of several tools available to the clinician for the rehabilitation of dysphagia. The two controlled clinical trials demonstrate that use of TES in dysphagia therapy is equivalent to traditional dysphagia therapy and of greater benefit only on one of several measures in one study. TES should be used only in patients who can overcome the resistive lowering of the hyo-laryngeal complex induced by TES which could place severely affected patients at greater risk of penetration.

Immediate effects of transcutaneous electrical stimulation on physiological swallowing effort in older versus young adults

OBJECTIVE

This study compared the immediate impact of different transcutaneous electrical stimulation (TES) amplitudes on physiological swallowing effort in healthy older adults versus young adults.

BACKGROUND

Swallowing physiology changes with age. Reduced physiological swallowing effort in older adults including lower lingua-palatal and pharyngeal pressures may increase risk for swallowing dysfunction (i.e. dysphagia). Transcutaneous electrical stimulation (TES) has been advocated as an adjunctive modality to enhance outcomes in exercise-based therapy for individuals with dysphagia. However, significant variation in how TES is applied during therapy remains and the physiological swallowing response to TES is poorly studied, especially in older adults.

MATERIALS AND METHODS

Physiological change in swallowing associated with no stimulation, sensory stimulation and motor stimulation was compared in 20 young adults versus 14 older adults. Lingua-palatal and pharyngeal manometric pressures assessed physiological swallowing effort.

RESULTS

Multivariate analyses identified interactions between age and stimulation amplitude on lingual and pharyngeal functions. Motor stimulation reduced anterior tongue pressure in both age groups but selectively reduced posterior lingua-palatal pressures in young adults only. Sensory stimulation increased base of tongue (BOT) pressures in older adults but decreased BOT pressures in young adults. Motor stimulation increased hypopharyngeal pressures in both groups.

CONCLUSION

Age and TES level interact in determining immediate physiological responses on swallow performance. A one-size-fit-all approach to TES in dysphagia rehabilitation may be misdirected.

Functional outcome in acute stroke patients with oropharyngeal Dysphagia after swallowing therapy

Dysphagia after stroke is associated with mortality and increased pulmonary complications. Swallowing therapies may decrease pulmonary complications and improve patients' quality of life after stroke. This study used clinical swallowing assessments and videofluoroscopy (VFS) to assess the functional recovery of acute stroke patients with dysphagia after different swallowing therapies. We enrolled 29 acute stroke patients with dysphagia and randomly divided them into 3 therapy groups: traditional swallowing (TS), oropharyngeal neuromuscular electrical stimulation (NMES), and combined NMES/TS. All patients were assessed using the clinical functional oral intake scale (FOIS), 8-point penetration-aspiration scale (PAS), and functional dysphagia scale (FDS) of VFS before and after treatment. There were no differences in the clinical parameters and swallowing results of the FOIS and VFS before swallowing treatment among the 3 groups (P > .05). TS therapy and combined therapy both had significant swallowing improvement after therapy according to the FOIS and 8-point PAS (P < .05). When comparing the results of the VFS among the 3 groups, we found significant improvements in patients eating cookies and thick liquid after combined NMES/TS therapy (P < .05). In acute stroke patients with dysphagia, combined NMES/TS therapy is the most effective swallowing therapy in taking solid diets and thick liquids.

[Neuromuscular electric stimulation therapy in otorhinolaryngology]

BACKGROUND

Animal experiments have shown that after specific nerve traumatization, neuromuscular electrostimulation (NMES) can promote nerve regeneration and reduce synkinesia without negatively interfering with normal regeneration processes. NMES is used routinely in physical rehabilitation medicine.

METHODS

This systematic literature search in the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, the DAHTA database, the Health Technology Assessment Database and MEDLINE or PubMed considered studies on the use of NMES in otorhinolaryngology that have been published in German or English.

RESULTS

The search identified 180 studies. These were evaluated and relevant studies were included in the further evaluation.

DISCUSSION

In the fields of otorhinolaryngology and phoniatry/paediatric audiology, clinical studies investigating the effects of NMES on facial and laryngeal paresis, as well as dysphonia and dysphagia have been carried out. The evidence collected to date is encouraging; particularly for the treatment of certain forms of dysphagia and laryngeal paresis.

Electrical stimulation in treatment of pharyngolaryngeal dysfunctions

OBJECTIVE

Neuromuscular electrical stimulation (NMES) has been proposed in the treatment of laryngopharyngeal dysfunctions (dysphonia, dyspnoea, dysphagia) for more than 40 years. Several studies have investigated possible therapeutic effects. Some researchers described favourable results, whereas others did not find relevant benefits. This article aims to review available studies to give an overview regarding the current state of knowledge.

METHODS

We conducted a selective literature search using PubMed.

RESULTS

In total, 356 papers were identified: 6 case reports, 11 reviews, 43 prospective clinical trials and 3 retrospective trials were found.

CONCLUSION

Due to different stimulation protocols, electrode positioning and various underlying pathological conditions, summarizing the present studies appears to be difficult. However, there is evidence that NMES is a valuable adjunct in patients with dysphagia and in patients with vocal fold paresis. Nevertheless, more empirical data is needed to fully understand the benefits provided by NMES. Further research suggestions are put forward.

Neuromuscular electrical stimulation of the cricothyroid muscle in patients with suspected superior laryngeal nerve weakness

In this retrospective case study, we report the apparent clinical effectiveness of neuromuscular electrical stimulation (NMES) in combination with voice therapy (VT) for rehabilitating dysphonia secondary to suspected superior laryngeal nerve (SLN) weakness in two female patients. Both patients failed or plateaued with traditional VT but had significant improvement with the addition of NMES of the cricothyroid muscle and SLN using a VitalStim unit. Stimulation was provided simultaneously with voice exercises based on musical phonatory tasks. Both acoustic analysis and endoscopic evaluation demonstrated important improvements after treatment. In the first patient, the major change was obtained within the primo passaggio region; specifically, a decrease in voice breaks was demonstrated. In the second patient, an improvement in voice quality (less breathiness) and vocal range were the most important findings. Additionally, each patient reported a significant improvement in their voice complaints. Neuromuscular laryngeal electrical stimulation in combination with vocal exercises might be a useful tool to improve voice quality in patients with SLN injury.

Effects of hypoglossal nerve block and electrical stimulation of the thyrohyoideus muscles on position of the larynx and hyoid apparatus in healthy horses

OBJECTIVE

To determine the effects of hypoglossal nerve block and electrical stimulation of the thyrohyoideus muscles on position of the larynx and hyoid apparatus in resting horses.

ANIMALS

16 healthy horses that underwent hypoglossal nerve block and 5 healthy horses that underwent electrical stimulation of the thyrohyoideus muscles.

PROCEDURES

Horses underwent bilateral hypoglossal nerve block or electrical stimulation of the thyrohyoideus muscles. Positions of the basihyoid bone, ossified part of the thyroid cartilage, and articulations of the thyrohyoid bones and thyroid cartilage were determined in radiographic images obtained before and after performance of hypoglossal nerve blocks or during thyrohyoideus muscle stimulation. Radiographic images were obtained with the heads of horses in neutral (thyrohyoideus muscle stimulation) or neutral and extended (hypoglossal nerve block) positions. Radiographic images of horses obtained after performance of hypoglossal nerve blocks were also evaluated to detect dorsal displacement of the soft palate.

RESULTS

Hypoglossal nerve blocks did not induce significant changes in the positions of evaluated anatomic sites in radiographic images obtained in neutral or extended head positions. Hypoglossal nerve block did not induce dorsal displacement of the soft palate in horses at rest. Bilateral thyrohyoideus muscle stimulation induced significant dorsal movement (mean ± SD change in position, 18.7 ± 6.8 mm) of the ossified part of the thyroid cartilage; rostral movement of evaluated anatomic structures was small and not significant after thyrohyoideus muscle stimulation.

CONCLUSIONS AND CLINICAL RELEVANCE

Bilateral electrical stimulation of the thyrohyoideus muscles in horses in this study induced dorsal laryngeal movement.

Kinematic effects of hyolaryngeal electrical stimulation therapy on hyoid excursion and laryngeal elevation

The purpose of this study was to assess the effect of repeated sessions of electrical stimulation therapy (EST) on the neck muscles with respect to the stimulation site by using quantitative kinematic analysis of videofluoroscopic swallowing studies (VFSS) in dysphagia patients with acquired brain injury. We analyzed 50 patients in a tertiary hospital who were randomly assigned into two different treatment groups. One group received EST on the suprahyoid muscle only (SM), and the other group received stimulation with one pair of electrodes on the suprahyoid muscle and the other pair on the infrahyoid muscle (SI). All patients received 10-15 sessions of EST over 2-3 weeks. The VFSS was carried out before and after the treatment. Temporal and spatial parameters of the hyoid excursion and laryngeal elevation during swallowing were analyzed by two-dimensional motion analysis. The SM group (n = 25) revealed a significant increase in maximal anterior hyoid excursion distance (mean ± SEM = 1.56 ± 0.52 mm, p = 0.008) and velocity (8.76 ± 3.42 mm/s, p = 0.017), but there was no significant increase laryngeal elevation. The SI group (n = 25), however, showed a significant increase in maximal superior excursion distance (2.09 ± 0.78 mm, p = 0.013) and maximal absolute excursion distance (2.20 ± 0.82 mm, p = 0.013) of laryngeal elevation, but no significant increase in hyoid excursion. There were no significant differences between the two groups with respect to changes in maximal anterior hyoid excursion distance (p = 0.130) and velocity (p = 0.254), and maximal distance of superior laryngeal elevation (p = 0.525). EST on the suprahyoid muscle induced an increase in anterior hyoid excursion, and infrahyoid stimulation caused an increase in superior laryngeal elevation. Hyolaryngeal structural movements were increased in different aspects according to the stimulation sites. Targeted electrical stimulation based on pathophysiology is necessary.

Evaluation of an EMG bioimpedance measurement system for recording and analysing the pharyngeal phase of swallowing

A neuroprosthetic device for treating swallowing disorders requires an implantable measurement system capable to analysing the timing and quality of the swallowing process in real time. A combined EMG bioimpedance (EMBI) measurement system was developed and is evaluated here. The study was planned and performed as a case-control study. The studies were approved by the Charité Berlin ethics committee in votes EA1/160/09 and EA1/161/09. Investigations were carried out on healthy volunteers in order to examine the usefulness and reproducibility of measurements, the ability to distinguish between swallowing and head movements and the effect of different food consistencies. The correlation between bioimpedance and anatomical and functional changes occurring during the pharyngeal phase of swallowing in non-healthy patients was examined using videofluoroscopy (VFSS). 31 healthy subjects (15♂, 16♀) were tested over the course of 1350 swallows and 19 (17♂, 2♀) non-healthy patients over the course of 54 swallows. The signal curves obtained from both transcutaneous and subcutaneous measurement were similar, characteristic and reproducible (r > 0.5) and correlated with anatomical and functional changes during the pharyngeal phase of swallowing observed using VFSS. Statistically significant differences between head movements and swallowing movements, food volumes and consistencies were found. Neither the conductivity of the food, the sex of the test subject nor the position of the measurement electrodes exerted a statistically significant effect on the measured signal. EMBI is able to reproducibly map the pharyngeal phase of swallowing and changes associated with it both transcutaneously and subcutaneously. The procedure therefore appears to be suitable for use in performing automated evaluation of the swallowing process and for use as a component of an implant.

Electrical stimulation and swallowing: how much do we know?

Consequences of dysphagia substantially reduce quality of life, increase the risk of medical complications and mortality, and pose a substantial cost to healthcare systems. As a result, it is of no wonder that the clinical and scientific communities are showing interest in new avenues for dysphagia rehabilitation. Electrical stimulation (e-stim) for the treatment of swallowing impairments is among the most studied swallowing interventions in the published literature, yet many unanswered questions about its efficacy remain. In the meantime, many speech-language pathologists who treat dysphagia are attending educational and training sessions to obtain certifications to use this technique. Here, we review the values and limitations of the published literature on the topic of e-stim for swallowing to assist clinicians in decision making in their clinical practice. The discussion provides a review of swallowing anatomy and physiology, the fundamentals of e-stim, and information essential for the readers' independent critique of these studies--all of which are crucial for evaluating the possible effects of e-stim.

Effects of effortful swallow on esophageal function in healthy adults

BACKGROUND

Treatment for esophageal dysmotility is currently limited to primarily pharmacologic intervention, which has questionable utility and frequently associated negative side effects. A potential behavioral intervention for esophageal dysmotility is the effortful oropharyngeal swallow. A previous pilot study using water perfusion manometry found an increase in distal esophageal amplitudes during effortful vs non-effortful swallowing. The current study sought to duplicate the previous study with improvements in methodology.

METHODS

The effects of swallow condition (effortful vs non-effortful), sensor site, and gender on esophageal amplitude, duration, velocity, and bolus clearance were examined for 18 adults (nine males and nine females, mean age = 29.9 years) via combined solid-state manometry and intraluminal impedance.

KEY RESULTS

The effortful swallow condition yielded significantly higher esophageal amplitudes across all sensor locations (P < 0.05). Further, the effortful swallowing decreased the risk of incomplete bolus clearance when compared with non-effortful swallowing (OR: 0.51; 95% CI: 0.30-0.86).

CONCLUSIONS & INFERENCES

With improved manometric instrumentation, larger participant numbers, and methodology that controlled for potential confounding factors, this study confirms and advances the results of the previous pilot study: Volitional manipulation of the oropharyngeal phase of swallowing using the effortful swallow indeed affects esophageal physiology. Thus, the effortful swallow offers a behavioral manipulation of the esophageal phase of swallowing, and future studies will determine its clinical potential for treating esophageal dysmotility in patient populations.

Electrical stimulation for the management of aspiration during swallowing

Protection of the airway during swallow is often compromised following stroke and other neurological diseases. If a patient fails to recover airway protection with standard therapy, they are often left with few if any options to avoid repeated pneumonia resulting from aspiration. For them, the only option is no food by mouth and a PEG-tube for nutrition. Functional electrical stimulation offers possible solutions for restoring airway protection. Here we report the capabilities of transtracheal stimulation for vocal fold closure and selective stimulation of the XII cranial nerve to produce elevation of the hyolaryngotracheal complex. These stimulation locations add to our toolbox for managing swallowing difficulties and allow patients to maintain oral feeding.

Prevention of aspiration pneumonia (AP) with oral care

AP is a major cause of morbidity and mortality in elderly patients, especially frail elderly patients. The aim of this article is to review effect of oral care, including oral hygiene and improvement of oral function, on the prevention of AP among elderly people in hospitals and nursing homes. There is now a substantial body of work studying the effect of oral care on the prevention of respiratory diseases. Oral hygiene, consisting of oral decontamination and mechanical cleaning by dental professionals, has resulted in significant clinical effects (decreased incidence of pneumonia and decreased mortality from respiratory diseases) in clinical randomized trials. Moreover, studies examining oral colonization by pneumonia pathogens have shown the effect of oral hygiene on eliminating these pathogens. In addition, swallowing training has been shown to improve the movement and function of swallowing-related muscles, also resulting in decreased incidence of pneumonia. These findings support the contention that oral care is effective in the prevention of AP.

Dysphagia in stroke: a new solution

Dysphagia is extremely common following stroke, affecting 13%–94% of acute stroke sufferers. It is associated with respiratory complications, increased risk of aspiration pneumonia, nutritional compromise and dehydration, and detracts from quality of life. While many stroke survivors experience a rapid return to normal swallowing function, this does not always happen. Current dysphagia treatment in Australia focuses upon prevention of aspiration via diet and fluid modifications, compensatory manoeuvres and positional changes, and exercises to rehabilitate paretic muscles. This article discusses a newer adjunctive treatment modality, neuromuscular electrical stimulation (NMES), and reviews the available literature on its efficacy as a therapy for dysphagia with particular emphasis on its use as a treatment for dysphagia in stroke. There is a good theoretical basis to support the use of NMES as an adjunctive therapy in dysphagia and there would appear to be a great need for further well-designed studies to accurately determine the safety and efficacy of this technique.