Electrical stimulation of hyoid muscles in post-stroke dysphagia

The Hyoid Bone Kinematics in Dysphagic Stroke Patients: Instantaneous Velocity, Acceleration and Temporal Sequence Matters

Hyoid bone excursion (HBE) is one of the most critical events in the pharyngeal phase of swallowing. Most previous studies focused on the total displacement and average velocity of HBE. However, HBE during swallowing is not one-dimensional, and the change of velocity and acceleration is not linear. This study aims to elucidate the relationship between the instantaneous kinematics parameters of HBE and the severity of penetration/aspiration and pharyngeal residue in patients with stroke. A total of 132 sets of video-fluoroscopic swallowing study images collected from 72 dysphagic stroke patients were analyzed. The maximal instantaneous velocity, acceleration, displacement, and the time required to reach these values in the horizontal and vertical axes were measured. Patients were grouped according to the severity of the Penetration-Aspiration Scale and the Modified Barium Swallow Impairment Profile- Pharyngeal Residue. The outcome was then stratified according to the consistencies of swallowing materials. Stroke patients with aspiration were associated with a lower maximal horizontal instantaneous velocity and acceleration of HBE, a shorter horizontal displacement, and prolonged time to maximal vertical instantaneous velocity compared to the non-aspirators. In patients with pharyngeal residue, the maximal horizontal displacement of HBE was decreased. After stratification according to bolus consistencies, the temporal parameters of HBE were more significantly associated with aspiration severity when swallowing thin bolus. Meanwhile spatial parameters such as displacement had a bigger influence on aspiration severity when swallowing viscous bolus. These novel kinematic parameters of HBE could provide important reference for estimating swallowing function and outcomes in dysphagic stroke patients.

Gastrointestinal Dysfunction in Stroke

Gastrointestinal (GI) complications are seen in over 50% of ischemic stroke survivors; the most common complications are dysphagia, constipation, and GI bleeding. The bidirectional relationship of the gut-brain axis and stroke has recently gained traction, wherein stroke contributes to gut dysbiosis (alterations in the normal host intestinal microbiome) and gut dysbiosis perpetuates poor functional neurologic outcomes in stroke. It is postulated that the propagation of proinflammatory cells and gut metabolites (including trimethylamine N-oxide and short-chain fatty acids) from the GI tract to the central nervous system play a central role in gut-brain axis dysfunction. In this review, we discuss the known GI complications in acute ischemic stroke, our current knowledge from experimental stroke models for gut-brain axis dysfunction in stroke, and emerging therapeutics that target the gut-brain axis.

Clinical Practice Guidelines for Oropharyngeal Dysphagia

OBJECTIVE

Dysphagia is a common clinical condition characterized by difficulty in swallowing. It is sub-classified into oropharyngeal dysphagia, which refers to problems in the mouth and pharynx, and esophageal dysphagia, which refers to problems in the esophageal body and esophagogastric junction. Dysphagia can have a significant negative impact one's physical health and quality of life as its severity increases. Therefore, proper assessment and management of dysphagia are critical for improving swallowing function and preventing complications. Thus a guideline was developed to provide evidence-based recommendations for assessment and management in patients with dysphagia.

METHODS

Nineteen key questions on dysphagia were developed. These questions dealt with various aspects of problems related to dysphagia, including assessment, management, and complications. A literature search for relevant articles was conducted using Pubmed, Embase, the Cochrane Library, and one domestic database of KoreaMed, until April 2021. The level of evidence and recommendation grade were established according to the Grading of Recommendation Assessment, Development and Evaluation methodology.

RESULTS

Early screening and assessment of videofluoroscopic swallowing were recommended for assessing the presence of dysphagia. Therapeutic methods, such as tongue and pharyngeal muscle strengthening exercises and neuromuscular electrical stimulation with swallowing therapy, were effective in improving swallowing function and quality of life in patients with dysphagia. Nutritional intervention and an oral care program were also recommended.

CONCLUSION

This guideline presents recommendations for the assessment and management of patients with oropharyngeal dysphagia, including rehabilitative strategies.

Electroacupuncture improves swallowing function in a post-stroke dysphagia mouse model by activating the motor cortex inputs to the nucleus tractus solitarii through the parabrachial nuclei

As a traditional medical therapy, stimulation at the Lianquan (CV23) acupoint, located at the depression superior to the hyoid bone, has been shown to be beneficial in dysphagia. However, little is known about the neurological mechanism by which this peripheral stimulation approach treats for dysphagia. Here, we first identified a cluster of excitatory neurons in layer 5 (L5) of the primary motor cortex (M1) that can regulate swallowing function in male mice by modulating mylohyoid activity. Moreover, we found that focal ischemia in the M1 mimicked the post-stroke dysphagia (PSD) pathology, as indicated by impaired water consumption and electromyographic responses in the mylohyoid. This dysfunction could be rescued by electroacupuncture (EA) stimulation at the CV23 acupoint (EA-CV23) in a manner dependent on the excitatory neurons in the contralateral M1 L5. Furthermore, neuronal activation in both the parabrachial nuclei (PBN) and nucleus tractus solitarii (NTS), which was modulated by the M1, was required for the ability of EA-CV23 treatment to improve swallowing function in male PSD model mice. Together, these results uncover the importance of the M1-PBN-NTS neural circuit in driving the protective effect of EA-CV23 against swallowing dysfunction and thus reveal a potential strategy for dysphagia intervention.

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.

Combined conventional speech therapy and functional electrical stimulation in acute stroke patients with dyphagia: a randomized controlled trial

BACKGROUND

Stroke is the main cause of oropharyngeal neurogenic dysphagia. Electrostimulation has been used as a therapeutic tool in these cases. However, there are few studies that prove its effectiveness. We evaluated the effect of functional electrostimulation as a complement to conventional speech therapy in patients with dysphagia after a stroke in a stroke unit.

METHODS

We performed a clinical, randomized, and controlled trial divided into intervention group (IG) (n = 16) and control group (CG) (n = 17). All patients were treated with conventional speech therapy, and the IG also was submitted to the functional electrotherapy. Primary outcomes were Functional Oral Ingestion Scale (FOIS) and Swallowing videoendoscopy (FEES). The degree of dysphagia was scored in functional, mild, moderate and severe dysphagia according to FEES procedure. Dysphagia Risk Evaluation Protocol (DREP) was considered a secondary outcome.

RESULTS

There was a significant difference regarding FOIS scores after 5 days of intervention in groups. Both groups also showed a tendency to improve dysphagia levels measured by FEES, although not statistically significant. Improvements on oral feeding was seen in both groups. No significant differences between groups before and after the intervention were detected by DREP scores. Electrical stimulation did not show additional benefits beyond conventional therapy when comparing outcomes between groups.

CONCLUSION

Conventional speech therapy improved oral ingestion even regardless the use of electrostimulation in a stroke unit.

TRIAL REGISTRATION

This research was registered in ClinicalTrials.gov (Identifier: NCT03649295 ) in 28/08/2018 and in the Brazilian Registry of Clinical Trials (ReBEC) (Register Number: RBR-56QK5J), approval date: 18/12/2018. HGF Ethics Committee Approval Number: N. 2.388.931.

Review of the effectiveness of neuromuscular electrical stimulation in the treatment of dysphagia - an update

BACKGROUND

Neuromuscular electrical stimulation (NMES) has been used as a treatment option in the therapy of dysphagia for several years. In a previous review of the literature, it was concluded that NMES might be a valuable adjunct in patients with dysphagia and in patients with vocal fold paresis. However, due to different stimulation protocols, electrode positioning and various underlying pathological conditions, it was difficult to compare the studies which were identified and it was concluded that more empirical data is needed to fully understand the benefits provided by NMES. The purpose of this systematic review is, therefore, to evaluate recent studies regarding a potential effectiveness of transcutaneous NMES applied to the anterior neck as a treatment for dysphagia considering these different aspects.

METHOD

For this systematic review, a selective literature research in PubMed has been carried out on 5^th May 2021 using the terms electrical stimulation AND dysphagia and screened for inclusion criteria by two reviewers in Rayyan. The search resulted in 62 hits.

RESULTS

Studies were excluded due to their publication language; because they did not meet inclusion criteria; because the topical focus was a different one; or because they did not qualify as level 2 studies. Eighteen studies were identified with varying patient groups, stimulation protocols, electrode placement and therapy settings. However, 16 studies have reported of beneficial outcomes in relation with NMES.

DISCUSSION

The purpose of this systematic review was to evaluate the most recent studies regarding a potential effectiveness of NMES as a treatment for oropharyngeal dysphagia considering different aspects. It could generally be concluded that there is a considerable amount of level 2 studies which suggest that NMES is an effective treatment option, especially when combined with TDT for patients with dysphagia after stroke and patients with Parkinson's disease, or with different kinds of brain injuries. Further research is still necessary in order to clarify which stimulation protocols, parameters and therapy settings are most beneficial for certain patient groups and degrees of impairment.

Post-stroke Dysphagia: Prognosis and Treatment-A Systematic Review of RCT on Interventional Treatments for Dysphagia Following Subacute Stroke

Purpose

Post-stroke dysphagia is an underdiagnosed but relevant complication, associated with worse outcome, dependency and quality of life of stroke survivors. Detailed mechanisms of post-stroke dysphagia are not very well understood, but established therapeutic concepts are needed. Different interventional studies have been published dealing with post-stroke dysphagia. This systematic review wants to collect and give an overview over the published evidence.

Methods

PubMed, Embase, Cochrane, CINAHL were searched for relevant interventional studies on post-stroke dysphagia in the (sub-)acute setting (within 3 months of stroke onset). The search has been filtered for randomized trials with an inactive control and the relevant data extracted.

Results

After initially finding 2,863 trials, finally 41 trials have been included. Seven different therapeutic concepts have been evaluated (Acupuncture, behavioral/physical therapy, drug therapy, neuromuscular electrical stimulation, pharyngeal electrical stimulation, transcranial direct current stimulation and repetitive transcranial magnetic stimulation). Studies of all modalities have shown some effect on post-stroke dysphagia with several studies raising concerns about the potential bias.

Conclusion

The amount and quality of studies are not enough to suggest certain therapies. Some therapeutical concepts (intensive physical therapy, transcranial magnetic stimulation, drug therapy) seem to be good potential therapeutic options, but further research is needed.

An overview of dysphagia rehabilitation for stroke patients

ABSTRACT Background: Dysphagia is characterized by difficulty in the swallowing pattern at any stage of this neuromuscular process. It is a frequent symptom after stroke. Objective: This study aimed to investigate the most commonly used phonoaudiological interventions as therapy for the treatment of swallowing disorders in patients with dysphagia after stroke. Methods: We performed a review of studies indexed in MEDLINE-PubMed, LILACS, Cochrane, and Clinical trials.gov focusing on speech-language interventions for adult dysphagic patients after stroke between January 2008 and January 2021. Results: Thirty-six articles of clinical trials were selected. Eleven different types of therapies have been studied. Studies on the efficacy of therapeutic interventions for the rehabilitation of adult patients with dysphagia after stroke are still scarce. Most techniques are combined with conventional therapy, so the effectiveness of the other techniques alone cannot be assessed. Conclusions: Therapeutic interventions should be selected in accordance with the possibilities and limitations of the patients, and especially with the findings of the clinical evaluation and with its objective.

Evaluating the Efficacy of VitalStim Electrical Stimulation Combined with Swallowing Function Training for Treating Dysphagia following an Acute Stroke

OBJECTIVES

This study explored the clinical efficacy of VitalStim electrical stimulation combined with swallowing function training for patients with dysphagia following an acute stroke.

METHODS

Seventy-two patients with dysphagia following an acute stroke were admitted to our hospital and were further divided into two groups using prospective research methods. There were 36 cases in each group according to the random number table method. The control group received conventional medical treatment and swallowing function training while the experimental group received conventional medical treatment and VitalStim electrical stimulation combined with swallowing function training.

RESULTS

The overall response rate of the experimental group (94.44%) was higher than that of the control group (77.78%), and the difference was statistically significant (p<0.05). Compared with before treatment, the upward and forward movement speeds of the hyoid bone, anterior movement speed, the grading score of the Kubota drinking water test, Caiteng's grading score, serum superoxide dismutase, 5-hydroxytryptamine, and norepinephrine levels, Fugl-Meyer Assessment score, and multiple quality of life scores of the two groups showed improvement after treatment. While the standard swallowing assessment score, serum malondialdehyde level, and National Institutes of Health Stroke Scale score decreased, the aforementioned indices showed a significant improvement in the experimental group (p<0.05).

CONCLUSION

The results of this study indicate that VitalStim electrical stimulation combined with swallowing function is effective for treating dysphagia following an acute stroke. It can effectively improve swallowing, neurological, and limb motor functions, reduce complications, promote physical recovery, and improve overall quality of life of patients.

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.

Effectiveness of Different Application Parameters of Neuromuscular Electrical Stimulation for the Treatment of Dysphagia after a Stroke: A Systematic Review

Background: Dysphagia causes severe complications among people with a stroke. Physiotherapy allows the cure of this pathology, and among the tools it offers is neuromuscular electrical stimulation. However, this is a technique that has not been protocolized. Therefore, it was considered necessary to carry out a systematic review on the efficacy of the various parameters of application of the neuromuscular electrical stimulation in dysphagia generated after a stroke. Methods: A systematic search for publications was conducted in March 2020 in the Pubmed, Cinahl, Medline, Web of Science and Scopus databases, using as search terms: Electric stimulation therapy, Deglutition disorders and Stroke. Results: 21 articles were obtained in which the application of neuromuscular electrical stimulation was applied in isolation (n = 7) or in combination with other techniques such as strengthening exercises and manual therapy techniques (n = 14), with this second modality of treatment having greater benefits for patients. Conclusion: The greatest efficacy of this technique is reached when applied at 60-80 Hz, 700 μs of pulse duration, at the motor intensity threshold and in sessions of 20–30 min.

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.

Swallowing therapy for dysphagia in acute and subacute stroke

BACKGROUND

Dysphagia (swallowing problems), which is common after stroke, is associated with increased risk of death or dependency, occurrence of pneumonia, poor quality of life, and longer hospital stay. Treatments provided to improve dysphagia are aimed at accelerating recovery of swallowing function and reducing these risks. This is an update of the review first published in 1999 and updated in 2012.

OBJECTIVES

To assess the effects of swallowing therapy on death or dependency among stroke survivors with dysphagia within six months of stroke onset.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (26 June 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 6) in the Cochrane Library (searched 26 June 2018), MEDLINE (26 June 2018), Embase (26 June 2018), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (26 June 2018), Web of Science Core Collection (26 June 2018), SpeechBITE (28 June 2016), ClinicalTrials.Gov (26 June 2018), and the World Health Organization International Clinical Trials Registry Platform (26 June 2018). We also searched Google Scholar (7 June 2018) and the reference lists of relevant trials and review articles.

SELECTION CRITERIA

We sought to include randomised controlled trials (RCTs) of interventions for people with dysphagia and recent stroke (within six months).

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, extracted data, assessed risk of bias, used the GRADE approach to assess the quality of evidence, and resolved disagreements through discussion with the third review author (PB). We used random-effects models to calculate odds ratios (ORs), mean differences (MDs), and standardised mean differences (SMDs), and provided 95% confidence intervals (CIs) for each.The primary outcome was functional outcome, defined as death or dependency (or death or disability), at the end of the trial. Secondary outcomes were case fatality at the end of the trial, length of inpatient stay, proportion of participants with dysphagia at the end of the trial, swallowing ability, penetration aspiration score, or pneumonia, pharyngeal transit time, institutionalisation, and nutrition.

MAIN RESULTS

We added 27 new studies (1777 participants) to this update to include a total of 41 trials (2660 participants).We assessed the efficacy of swallowing therapy overall and in subgroups by type of intervention: acupuncture (11 studies), behavioural interventions (nine studies), drug therapy (three studies), neuromuscular electrical stimulation (NMES; six studies), pharyngeal electrical stimulation (PES; four studies), physical stimulation (three studies), transcranial direct current stimulation (tDCS; two studies), and transcranial magnetic stimulation (TMS; nine studies).Swallowing therapy had no effect on the primary outcome (death or dependency/disability at the end of the trial) based on data from one trial (two data sets) (OR 1.05, 95% CI 0.63 to 1.75; 306 participants; 2 studies; I² = 0%; P = 0.86; moderate-quality evidence). Swallowing therapy had no effect on case fatality at the end of the trial (OR 1.00, 95% CI 0.66 to 1.52; 766 participants; 14 studies; I² = 6%; P = 0.99; moderate-quality evidence). Swallowing therapy probably reduced length of inpatient stay (MD -2.9, 95% CI -5.65 to -0.15; 577 participants; 8 studies; I² = 11%; P = 0.04; moderate-quality evidence). Researchers found no evidence of a subgroup effect based on testing for subgroup differences (P = 0.54). Swallowing therapy may have reduced the proportion of participants with dysphagia at the end of the trial (OR 0.42, 95% CI 0.32 to 0.55; 1487 participants; 23 studies; I² = 0%; P = 0.00001; low-quality evidence). Trial results show no evidence of a subgroup effect based on testing for subgroup differences (P = 0.91). Swallowing therapy may improve swallowing ability (SMD -0.66, 95% CI -1.01 to -0.32; 1173 participants; 26 studies; I² = 86%; P = 0.0002; very low-quality evidence). We found no evidence of a subgroup effect based on testing for subgroup differences (P = 0.09). We noted moderate to substantial heterogeneity between trials for these interventions. Swallowing therapy did not reduce the penetration aspiration score (i.e. it did not reduce radiological aspiration) (SMD -0.37, 95% CI -0.74 to -0.00; 303 participants; 11 studies; I² = 46%; P = 0.05; low-quality evidence). Swallowing therapy may reduce the incidence of chest infection or pneumonia (OR 0.36, 95% CI 0.16 to 0.78; 618 participants; 9 studies; I² = 59%; P = 0.009; very low-quality evidence).

AUTHORS' CONCLUSIONS

Moderate- and low-quality evidence suggests that swallowing therapy did not have a significant effect on the outcomes of death or dependency/disability, case fatality at the end of the trial, or penetration aspiration score. However, swallowing therapy may have reduced length of hospital stay, dysphagia, and chest infections, and may have improved swallowing ability. However, these results are based on evidence of variable quality, involving a variety of interventions. Further high-quality trials are needed to test whether specific interventions are effective.

Effect of Early Enteral Nutrition Support on Nitrogen Balance and Nihss Score in Elderly Patients With Acute Cerebral Stroke and Dysphagia

The aim of this study was to evaluate the clinical efficacy of early enteral nutrition support (EENS) on nitrogen balance and National Institute of Health stroke scale (NIHSS) in elderly patients with acute cerebral stroke and dysphagia. Sixty-eight patients diagnosed with acute brain stroke (ABS) were retrospectively analyzed in our hospital database. Of the included 68 ABS subjects, 37 patients were given early EENS within 72h after ABS diagnosis (experiment group) and the other 31 cases were given a regular liquid diet (control group). The nitrogen balance 1, 2, 3 and 4 weeks after EENS were -4.3 ± 1.3, -3.4 ± 1.1, -2.6 ± 1.2 and -2.0 ± 1.1(g/d) respectively for the experiment group and -8.5 ± 3.1, -7.0 ± 2.4, -6.2 ± 1.5 and -5.7 ± 1.1 (g/d) respectively for the control group. This indicated that the nitrogen balance in the experimental group was significantly higher than that of the control group (p<0.05). After treatment, the NIHSS score were 7.3 ± 2.3 and 7.4 ± 2.4 in the experimental and control groups respectively with statistically significant difference (p<0.05). The risk of developing regurgitation, diarrhea and ventosity in the experimental group were significantly lower than that of the control group (p<0.05). EENS can quickly improve the burden of ABS in elderly patients, elevate the nutritional level and reduce the risk of related complications.