Surface electrical stimulation for treating swallowing disorders after stroke: a review of the stimulation intensity levels and the electrode placements

Stochastic electrical stimulation of the thoracic or cervical regions with surface electrodes facilitates swallow in rats

Introduction

Aspiration pneumonia, a leading cause of mortality, poses an urgent challenge in contemporary society. Neuromuscular electrical stimulation (NMES) has been commonly used in dysphagia rehabilitation. However, given that NMES at motor threshold targets only specific muscles, it carries a potential risk of further compromising functions related to swallowing, respiration, and airway protection. Considering that the swallow motor pattern is orchestrated by the entire swallow pattern generator (the neural mechanism governing a sequence of swallow actions), a rehabilitation approach that centrally facilitates the entire circuit through sensory nerve stimulation is desirable. In this context, we propose a novel stimulation method using surface electrodes placed on the back to promote swallowing.

Methods

The efficacy of the proposed method in promoting swallowing was evaluated by electrically stimulating sensory nerves in the back or neck. Probabilistic stimulus was applied to either the back or neck of male and female rats. Swallows were evoked by an oral water stimulus, and electromyographic (EMG) activity of the mylohyoid, thyroarytenoid, and thyropharyngeus muscles served as the primary outcome measure.

Results

Gaussian frequency stimulation applied to the skin surface of the thoracic back elicited significant increases in EMG amplitude of all three swallow-related muscles. Neck stimulation elicited a significant increase in EMG amplitude of the thyroarytenoid during swallow, but not the mylohyoid or thyropharyngeus muscles.

Discussion

While the targeted thoracic spinal segments T9-T10 have been investigated for enhancing respiration, the promotion of swallowing through back stimulation has not been previously studied. Furthermore, this study introduces a new probabilistic stimulus based on Gaussian distribution. Probabilistic stimuli have been reported to excel in nerve stimulation in previous research. The results demonstrate that back stimulation effectively facilitated swallow more than neck stimulation and suggest potential applications for swallowing rehabilitation.

Neuromuscular Electrical Stimulation for Post-Stroke Dysphagia Treatment: A Systemic Evaluation and Meta-Analysis of Randomized Controlled Trials

Neuromuscular electrical stimulation (NMES) is a novel treatment method that stimulates patients' swallowing functions. This systemic review was designed to evaluate the impact of NMES on dysphagia in stroke patients. Databases including PubMed, Embase, Web of Science, and Cochrane Library were searched from the date of establishment to January 28th, 2022. Two investigators identified all included studies and compared the swallowing function after NMES treatment with traditional therapy (TT). The Cochrane risk bias assessment tool was utilized to analyze the quality of included studies. Research outcomes included Swallowing Quality of Life (SWAL-QoL), Penetration-Aspiration Scale (PAS), Functional Oral Intake Scale (FOIS), Dysphagia Outcomes and Severity Scale (DOSS), the Repeat Salivary Swallowing Test (RSST), and Water Swallowing Test (WST). We extracted the mean and standard deviation of specific outcomes at the baseline level and after the treatment in both NMES and TT groups for subsequent meta-analysis. 9 randomized controlled trials (RCTs) and quasi-RCTs were included, and remarkable differences were found between patients treated with or without NMES in respect of FOIS scores (SMD = 0.48; 95% CI 0.26-0.70, P < 0.0001), PAS scores (SMD = - 0.56; 95% CI 1.01-0.10, P = 0.02), and SWAL-QoL scores (SMD = 0.57; 95% CI 0.00-1.14, P = 0.05). No significant difference was manifested in WST, RSST, and DOSS (SMD: - 0.02; 95% CI  0.38-0.35, P = 0.93). Evidence suggests that NMES is more effective for post-stroke dysphagia patients than treatment without NMES.

Treatment of Post-stroke Dysphagia With Interferential Current: Three Case Reports and a Review of the Literature

Stroke is damage to the central nervous system due to vascular pathology. Stroke causes many complications. One of the most important of these complications is dysphagia. Dysphagia is a major cause of morbidity and mortality. In recent years, the benefits of using interferential current (IFC) stimulation in the treatment of dysphagia due to various etiologies have been demonstrated. However, there are significant gaps in the literature regarding patient populations, treatment procedures, and evaluation of treatment response. Here, we report the treatment of three cases of dysphagia after ischemic stroke with IFC stimulation and review the current literature. The patients had no previous treatment for dysphagia and were using only compensatory methods. This case report highlights the benefit of IFC stimulation in the treatment of post-stroke dysphagia both clinically and videofluoroscopically. It should be kept in mind that IFC stimulation may be an important alternative in the treatment of post-stroke dysphagia.

Effectiveness of Conventional Dysphagia Therapy (CDT), Neuromuscular Electrical Stimulation (NMES), and Transcranial Direct Current Stimulation (tDCS) in Acute Post-Stroke Dysphagia: A Comparative Evaluation

This study aims to compare the effectiveness of conventional dysphagia therapy (CDT), neuromuscular electrical stimulation (NMES), and transcranial direct current stimulation (tDCS) in the treatment of post-stroke dysphagia. A single-blind randomized controlled trial was conducted with 40 acute stroke patients - 18 females and 22 males with a mean age of 65.8 ± 11.9. The subjects were grouped into 4, with 10 individuals in each. The procedures administered to groups were as follows: the first group, sham tDCS and sham NMES; the second group, tDCS and sham NMES; the third group, NMES and sham tDCS; and the fourth group, all therapy procedures. CDT was applied to all groups either as a standalone procedure or combined with one or two of the instrumental techniques. Gugging Swallowing Screen (GUSS) and Videofluoroscopic Swallowing Study (VFSS) were employed to determine the severity of dysphagia and the effectiveness of treatment modalities. Additionally, the Penetration Aspiration Scale (PAS), Functional Oral Intake Scale (FOIS), and Dysphagia Severity Rating Scale (DSRS) were administered to interpret VFSS data. Pre- and post-treatment comparisons of all groups have revealed a statistically significant difference for all parameters except for the PAS scores at International Dysphagia Diet Standardization Initiative (IDDSI)-Level 4 consistencies. However, the differences between pre- and post-treatment scores of the fourth group across all parameters were significant - GUSS (p = 0.005), FOIS (p = 0.004), DSRS (p = 0.005), PAS IDDSI-4 (p = 0.027), PAS IDDSI-0 (p = 0.004). Inter-group comparisons, on the other hand, pointed out that the difference between pre- and post-treatment GUSS, FOIS, DSRS, and PAS scores at IDDSI Level-0 consistencies was statistically significant for all groups - GUSS (p = 0,009), FOIS (p = 0,004), DSRS (p = 0,002), PAS IDDSI-0 (p = 0,049). Closer examination of treatment groups indicated that the tDCS + CDT group, the NMES + CDT group, and the group that underwent the combination of three modalities made better progress than the one that was treated with only CDT. Though not statistically significant, the NMES + CDT group achieved better improvement than the tDCS + CDT group. This study has yielded that the group in which NMES, tDCS, and CDT were applied in combination has achieved better results than all the other groups. All treatment modalities applied to accelerate the general recovery process in acute stroke patients with dysphagia were found to be effective for the treatment of post-stroke swallowing disorders. The use of instrumental treatments such as NMES and tDCS enhanced the effectiveness of the treatment and provided more significant progress. Furthermore, combining treatment modalities such as NMES and tDCS was more effective when compared to using only conventional therapy. As a result, the most effective treatment outcomes were obtained by the group receiving CDT, NMES, and tDCS in combination. Therefore, the use of combined approaches has been recommended in appropriate patients; yet the provisional results should be tested in randomized trials with more participants.

Sensory neuromuscular electrical stimulation for dysphagia rehabilitation: A literature review

BACKGROUND

Dysphagia is a common disorder following a cerebrovascular accident. It can cause detrimental effects on patient's quality of life and nutrition intake, especially in older adults. Neuromuscular electrical stimulation has been one of the management strategies for acceleration of the recovery. This review summarises the current evidence on sensory threshold stimulation of the procedure.

METHOD

This review compiled data from the Internet database PubMed, Cochrane Library and Scopus using combination of MeSH thesaurus: 'Sensory threshold', 'electrical stimulation', 'neuromuscular stimulation', 'Deglutition', 'Dysphagia'. Eleven studies were intergraded into the review.

RESULTS

Most of the studies show significant improvement to the outcomes of sensory neuromuscular electrical stimulation treatment. In many cases, the results of the treatment are comparable or superior to motor threshold stimulation and conventional therapy. However, the study design and parameters of the procedure varied greatly without conclusive standardised guidelines.

CONCLUSION

The sensory neuromuscular electrical stimulation (SNMES) is a viable treatment option for treating oropharyngeal dysphagia. The most suggested application parameters are an intensity at sensory threshold, a frequency of 80 Hz, an impulse time of 700 μs, a combined total duration of 20 h of stimulation in a 2-week period, and placing the electrodes in the submental area of the neck. However, further research is necessary to construct a definitive guideline for clinicians.

Dysphagia, dysphonia and olfactory disease: a map of Cochrane evidence relevant to rehabilitation for people with post COVID-19 condition

INTRODUCTION

Currently, no evidence exists on specific treatments for post COVID-19 condition (PCC). However, rehabilitation interventions that proved effective for similar symptoms in other health conditions could be applied to people with PCC. With this overview of systematic reviews with mapping, we aimed to describe the Cochrane evidence on rehabilitation interventions proposed for dysphagia, dysphonia and olfactory dysfunction in different health conditions that can be relevant for PCC.

EVIDENCE ACQUISITION

We searched the last five years' Cochrane Systematic Review (CSRs) using the terms "dysphagia," "swallowing disorder," "dysphonia," "voice disorder," "olfactory dysfunction," "smell changes" and "rehabilitation" in the Cochrane Library. We extracted and summarized the available evidence using a map. We grouped the included CSRs for health conditions and interventions, indicating the effect and the quality of evidence.

EVIDENCE SYNTHESIS

We found 170 CSRs published between 2016 and 2021 and 1 was included. It provided data on dysphagia in acute and subacute stroke. Interventions included were acupuncture, neuromuscular electrical stimulation, transcranial magnetic stimulation and behavioral interventions, and swallowing therapy, with very low- to moderate-quality evidence. We did not find any CSR on dysphonia and olfactory disease.

CONCLUSIONS

These results are the first step of indirect evidence able to generate helpful hypotheses for clinical practice and future research. They served as the basis for the three recommendations on treatments for these PCC symptoms published in the current WHO Guidelines for clinical practice.

Neuromuscular electrical stimulation improves swallowing initiation in patients with post-stroke dysphagia

Objective

More than half of post-stroke patients develop dysphagia, which manifests as delayed swallowing and is associated with a high risk of aspiration. In this study, we aimed to investigate the immediate effect of neuromuscular electrical stimulation (NMES) on swallowing initiation in post-stroke patients using videofluoroscopic swallowing study (VFSS) data.

Materials and methods

This randomized, self-controlled crossover study included 35 patients with post-stroke dysphagia. All selected patients received real and sham NMES while swallowing 5 ml of thin liquid. Participants completed the conditions in random order, with a 10-min interval between conditions. The primary evaluation indicators included the Modified Barium Swallow Impairment Profile-6 (MBSImp-6) and Penetration-Aspiration Scale (PAS). Secondary indicators included oral transit time (OTT), pharyngeal transit time (PTT), and laryngeal closure duration (LCD).

Results

Modified Barium Swallow Impairment Profile-6 (P = 0.008) and PAS (P &lt; 0.001) scores were significantly lower in the Real-NMES condition than in the Sham-NMES condition. OTT (P &lt; 0.001) was also significantly shorter during Real-NMES than during Sham-NMES. However, LCD (P = 0.225) and PTT (P = 0.161) did not significantly differ between the two conditions.

Conclusion

Neuromuscular electrical stimulation may represent a supplementary approach for promoting early feeding training in patients with post-stroke dysphagia.

Clinical trial registration

[https://clinicaltrials.gov/], identifier [ChiCTR2100052464].

The Effect of Sensory Level Versus Motor Level Electrical Stimulation of Pharyngeal Muscles in Acute Stroke Patients with Dysphagia: A Randomized Trial

Dysphagia is a serious cause of morbidity and mortality in stroke survivors. Electrical stimulation is often included as part of the treatment plan for dysphagia and can be applied at a sensory or motor level intensity. However, evidence to support these different modes of stimulation is lacking. This study compared the effectiveness of sensory and motor level stimulation on post-stroke dysphagia. This is a randomized trial conducted in an inpatient rehabilitation facility. Thirty-one participants who had dysphagia caused by stroke within 6 months prior to enrolment were included. Participants were excluded if they had a contraindication for electrical stimulation, previous stroke, psychiatric disorder, contraindications for modified barium swallow study (MBSS), or pre-morbid dysphagia. Each patient received ten sessions that included 45 min of anterior neck sensory or motor level electrical stimulation in addition to traditional dysphagia therapy. Motor stimulation was administered at an intensity sufficient to produce muscle contractions. Sensory stimulation was defined as the threshold at which the patient feels a tingling sensation on their skin. Swallow functional assessment measure (FAM), dysphagia outcome severity scale (DOSS), national outcome measurement system (NOMS), penetration aspiration scale (PAS), diet change, and the swallowing quality of life questionnaire (SWAL-QOL). Clinical outcomes were analyzed using a Wilcoxon signed-rank test, Mann–Whitney U test, RM ANOVA, or chi-square analysis. There was no significant difference in age, length of stay, or initial swallow FAM between groups. Patients in the sensory group showed significant improvement on swallow FAM, DOSS, and NOMS, while those in the motor group did not (Sensory: Swallow FAM (S = 48, p = 0.01), DOSS (S = 49.5, p = 0.001), NOMS (S = 52.5, p = 0.006); Motor: Swallow FAM (S = 20.5, p = 0.2), DOSS (S = 21, p = 0.05), NOMS (S = 29.5, p = 0.2)). When the groups were combined, there was statistically significant improvement on all measures except the PAS (Swallow FAM (S = 138.5, p = 0.003), DOSS (S = 134.5, p < 0.001), NOMS (S = 164, p = 0.0004)). When comparing motor to sensory NMES, there was no significant difference between groups for Swallow FAM (p = .12), DOSS (p = 0.52), or NOMS (p = 0.41). There was no significant difference in diet change for solid food or liquids among the groups, although 50% more participants in the sensory group saw improvement in diet. This study supports the use of electrical stimulation as part of the treatment plan for post-stroke dysphagia. Sensory-level stimulation was associated with greater improvement on outcome measures compared to motor level stimulation.

The Effects of Neuromuscular Electrical Stimulation on Swallowing Functions in Post-stroke Dysphagia: A Randomized Controlled Trial

The study aimed to evaluate the effects of traditional dysphagia therapy (TDT) and neuromuscular electrical stimulation (NMES) combined with TDT on functionality of oral intake, dysphagia symptom severity, swallowing- and voice-related quality of life, leakage, penetration-aspiration, and residue levels in patients with post-stroke dysphagia (PSD). Thirty-four patients with PSD were included in our prospective, randomized, controlled, and single-blind study. The patients were divided into two groups: (1) TDT only (control group, n = 17) and (2) TDT with NMES (experimental group, n = 17). TDT was applied to both groups for three consecutive weeks, 5 days a week, 45 min a day. Sensory NMES was applied to the experimental group for 45 min per session. Patients were evaluated by the functional oral intake scale (FOIS), the eating assessment tool (EAT-10), the swallowing quality of life questionnaire (SWAL-QOL), and the voice-related quality of life questionnaire (VRQOL) at baseline, immediately post-intervention, and at the 3rd month post-intervention. Fiberoptic endoscopic evaluation of swallowing (FEES) with liquid and semi-solid food was performed pre- and post-intervention. A significant post-intervention improvement was observed on all scales in both groups, and these improvements were maintained 3 months post-intervention. Leakage and penetration-aspiration levels with semi-solid food declined only in the experimental group. In conclusion, TDT is a non-invasive and inexpensive method that leads to improvement in many swallowing-related features in stroke patients; however, NMES as an adjunct therapy is costly but can provide additional benefits for improving features, such as penetration-aspiration and residue levels.

Best Practice Recommendations for Stroke Patients with Dysphagia: A Delphi-Based Consensus Study of Experts in Turkey-Part II: Rehabilitation

Dysphagia is one of the most common and important complications of stroke. It is an independent marker of poor outcome following acute stroke and it continues to be effective for many years. This consensus-based guideline is not only a good address to clinical questions in practice for the clinical management of dysphagia including management, diagnosis, follow-up, and rehabilitation methods, but also includes detailed algorithms for these topics. The recommendation paper has been written by a multidisciplinary team and offers 117 recommendations for stroke patients with dysphagia. While focusing on management principles, diagnosis, and follow-up in the 1st part (45 items), rehabilitation details were evaluated in the 2nd part (72 items).

The effect of neuromuscular electrical stimulation with different electrode positions on swallowing in stroke patients with oropharyngeal dysphagia: A randomized trial

OBJECTIVE

To examine the effects of neuromuscular electrical stimulation (NMES) on oropharyngeal swallowing function according to 2 types of placement, acting as assistance and as resistance, in stroke patients with dysphagia.

METHODS

Thirty-eight stroke patients with dysphasia were randomly assigned to the suprahyoid group (SMG), or infrahyoid muscle group (IMG); 26 patients completed the intervention and were included in the analysis. In the SMG, the electrodes were placed on the region between the jaw and the hyoid bone, whereas in the IMG, the electrodes were placed on the region below the hyoid for the targeted infrahyoid muscles. Both groups received NMES for 30 min/d, 5 d/wk, for 4 weeks and conventional dysphagia therapy. Swallowing function was measured using the Videofluoroscopic Dysphagia Scale and Penetration-Aspiration Scale based on videofluoroscopic swallowing study. Oral dietary intake was measured using the Functional Oral Intake Scale.

RESULTS

Both groups showed significant improvements in oropharyngeal function and level of functional oral intake, but there was no significant difference between the two groups. However, the SMG showed a more reduced penetration-aspiration, compared with the IMG.

CONCLUSIONS

Altogether, these data demonstrate that 2 types of NMES placements have a similar effect on improving swallowing function and oral diet intake in patients with dysphagia.

Effectiveness of Neuromuscular Electrical Stimulation on Post-Stroke Dysphagia: A Systematic Review of Randomized Controlled Trials

The purpose of this review was to summarize the latest best scientific evidence on the efficacy of neuromuscular electrical stimulation on swallowing function in dysphagic stroke patients. A comprehensive systematic search of literature published between November 2014 and May 2020 was performed using the following electronic databases: PubMed/Medline, CINAHL, PEDro, Science Direct, Google Scholar, EMBASE, and Scopus. Only randomized controlled trials (RCT) evaluating the effect of neuromuscular electrical stimulation on swallowing function in dysphagic stroke patients were included. Physiotherapy Evidence Database (PEDro) has been used to evaluate the risk of bias of included trials. This review was reported in accordance with PRISMA statement guideline. The methodological quality of the studies was determined using PEDro scale and GRADE approach. Evidence of overall quality was graded from moderate to high. Eleven RCTs involving 784 patients were analyzed. The primary outcome measures of this review were functional dysphagia scale (FDS) and standard swallowing assessment. This review found neuromuscular electrical stimulation (NMES) coupled with traditional swallowing therapy could be an optional intervention to improve swallowing function after stroke in rehabilitation department.

Swallow Motor Pattern Is Modulated by Fixed or Stochastic Alterations in Afferent Feedback

Afferent feedback can appreciably alter the pharyngeal phase of swallow. In order to measure the stability of the swallow motor pattern during several types of alterations in afferent feedback, we assessed swallow during a conventional water challenge in four anesthetized cats, and compared that to swallows induced by fixed (20 Hz) and stochastic (1-20Hz) electrical stimulation applied to the superior laryngeal nerve. The swallow motor patterns were evaluated by electromyographic activity (EMG) of eight muscles, based on their functional significance: laryngeal elevators (mylohyoid, geniohyoid, and thyrohyoid); laryngeal adductor (thyroarytenoid); inferior pharyngeal constrictor (thyropharyngeus); upper esophageal sphincter (cricopharyngeus); and inspiratory activity (parasternal and costal diaphragm). Both the fixed and stochastic electrical stimulation paradigms increased activity of the laryngeal elevators, produced short-term facilitation evidenced by increasing swallow durations over the stimulus period, and conversely inhibited swallow-related diaphragm activity. Both the fixed and stochastic stimulus conditions also increased specific EMG amplitudes, which never occurred with the water challenges. Stochastic stimulation increased swallow excitability, as measured by an increase in the number of swallows produced. Consistent with our previous results, changes in the swallow motor pattern for pairs of muscles were only sometimes correlated with each other. We conclude that alterations in afferent feedback produced particular variations of the swallow motor pattern. We hypothesize that specific SLN feedback might modulate the swallow central pattern generator during aberrant feeding conditions (food/liquid entering the airway), which may protect the airway and serve as potentially important clinical diagnostic indicators.

Clinical Effects and Differences in Neural Function Connectivity Revealed by MRI in Subacute Hemispheric and Brainstem Infarction Patients With Dysphagia After Swallowing Therapy

Background: Early detection and intervention for post-stroke dysphagia could reduce the incidence of pulmonary complications and mortality. The aims of this study were to investigate the benefits of swallowing therapy in swallowing function and brain neuro-plasticity and to explore the relationship between swallowing function recovery and neuroplasticity after swallowing therapy in cerebral and brainstem stroke patients with dysphagia.

Methods: We collected 17 subacute stroke patients with dysphagia (11 cerebral stroke patients with a median age of 76 years and 6 brainstem stroke patients with a median age of 70 years). Each patient received swallowing therapies during hospitalization. For each patient, functional oral intake scale (FOIS), functional dysphagia scale (FDS) and 8-point penetration-aspiration scale (PAS) in videofluoroscopy swallowing study (VFSS), and brain functional magnetic resonance imaging (fMRI) were evaluated before and after treatment.

Results: FOIS (p = 0.003 in hemispheric group and p = 0.039 in brainstem group) and FDS (p = 0.006 in hemispheric group and p = 0.028 in brainstem group) were both significantly improved after treatment in hemispheric and brainstem stroke patients. In hemispheric stroke patients, changes in FOIS were related to changes of functional brain connectivity in the ventral default mode network (vDMN) of the precuneus in brain functional MRI (fMRI). In brainstem stroke patients, changes in FOIS were related to changes of functional brain connectivity in the left sensorimotor network (LSMN) of the left postcentral region characterized by brain fMRI.

Conclusion: Both hemispheric and brainstem stroke patients with different swallowing difficulties showed improvements after swallowing training. For these two dysphagic stroke groups with corresponding etiologies, swallowing therapy could contribute to different functional neuroplasticity.

Supportive effect of interferential current stimulation on susceptibility of swallowing in guinea pigs

Sensory-motor control of the pharyngeal swallow requires sensory afferent inputs from the pharynx and larynx evoked by introducing bolus into the pharynx. Patients with reduced sensitivity of the pharynx and larynx are likely to have a swallowing impairment, such as pre-swallow aspiration due to delayed swallow triggering. Interferential current stimulation applied to the neck is thought to improve the swallowing function of dysphagic patients, although the mechanism underlying the facilitatory effect of such stimulation remains unknown. In the present study, we examined the changes in the elicitability of swallowing due to the stimulation and the responses of the swallowing-related neurons in the nucleus tractus solitarius and in the area adjacent to the stimulation in decerebrate and paralyzed guinea pigs. The swallowing delay time was shortened by the stimulation, whereas the facilitatory effect of eliciting swallowing was attenuated by kainic acid injection into the nucleus tractus solitarius. Approximately half of the swallowing-related neurons responded to the stimulation. These data suggest that the interferential current stimulation applied to the neck could enhance the sensory afferent pathway of the pharynx and larynx, subserving excitatory inputs to the neurons of the swallowing pattern generator, thereby facilitating the swallowing reflex.

Use of Textured Thin Liquids in Patients With Dysphagia

PURPOSE

The goals of this article are to explore the use of textured thin liquids for dysphagic patients who require thickened liquids and to illustrate their impact on hydration and patient satisfaction.

METHOD

A retrospective evaluation of textured thin liquids was completed using patient data looking at laboratory values relevant to the detection of dehydration (blood urea nitrogen, creatinine, sodium) and patient satisfaction (using a clinician-generated questionnaire) on different modified liquid textures. In addition, the viscosity for all liquids was tested using a rheometer.

RESULTS

Measurements show that the viscosity of the textured thin liquids examined in this pilot study are significantly lower than the viscosity of nectar-thick liquids and fall within the "thin" category as defined by the National Dysphagia Diet guidelines. Patients on honey- and nectar-thick liquids had laboratory values signifying dehydration, whereas those receiving the textured thin liquid consistency were within the normal range for all laboratory values. Importantly, when consuming textured thin liquids, patients reported significant improvement in their satisfaction related to their thirst.

CONCLUSION

The results of this pilot study highlight the consequences of common thickened liquid dietary recommendations and of the potentially beneficial clinical application of textured thin liquids for patients with dysphagia as well as the need for future prospective research.

Review of devices used in neuromuscular electrical stimulation for stroke rehabilitation

Neuromuscular electrical stimulation (NMES), specifically functional electrical stimulation (FES) that compensates for voluntary motion, and therapeutic electrical stimulation (TES) aimed at muscle strengthening and recovery from paralysis are widely used in stroke rehabilitation. The electrical stimulation of muscle contraction should be synchronized with intended motion to restore paralysis. Therefore, NMES devices, which monitor electromyogram (EMG) or electroencephalogram (EEG) changes with motor intention and use them as a trigger, have been developed. Devices that modify the current intensity of NMES, based on EMG or EEG, have also been proposed. Given the diversity in devices and stimulation methods of NMES, the aim of the current review was to introduce some commercial FES and TES devices and application methods, which depend on the condition of the patient with stroke, including the degree of paralysis.

Surface electrical stimulation perturbation context determines the presence of error reduction in swallowing hyolaryngeal kinematics

PURPOSE

Error-based learning (EBL) involves gradually reducing movement errors caused by a perturbation. When the perturbation has been unexpectedly removed, exaggerated movements occur in the opposite direction of a perturbation effect, known as aftereffects. Our goal was to determine whether the perturbation type impacts error reduction or aftereffects in swallowing hyolaryngeal kinematics.

METHOD

We perturbed peak hyolaryngeal elevation during swallowing in 16 healthy adults with surface electrical stimulation (SES) in 2 different ways during videofluoroscopy: intermittent SES (I-SES) was applied only during swallowing, and continuous SES (C-SES) was applied during swallowing and during interswallow intervals. In C-SES and I-SES, the onset and offset of the perturbation were unmasked.

RESULTS

Only the C-SES perturbation caused error reduction (gradually increasing peak elevation). Aftereffects were absent in both perturbations, unlike findings from our previous study with masked perturbation. Furthermore, the duration of laryngeal vestibule closure (dLVC) increased during the I-SES perturbation but was unchanged during C-SES perturbation.

CONCLUSION

EBL of swallowing airway protection events was strongly influenced by the context of the perturbation. These findings also elucidate how the relationship among critical swallowing airway protection events (hyoid peak, laryngeal peak, and dLVC) can be modified during EBL.