Submental Muscle Activity and Its Role in Diagnosing Sarcopenic Dysphagia

Impact of rTMS and iTBS on Cerebral Hemodynamics and Swallowing in Unilateral Stroke: Insights from fNIRS

BACKGROUND Swallowing is a complex behavior involving the musculoskeletal system and higher-order brain functions. We investigated the effects of different modalities of repetitive transcranial magnetic stimulation (rTMS) on the unaffected hemisphere and observed correlation between suprahyoid muscle activity and cortical activation in unilateral stroke patients when swallowing saliva, based on functional near-infrared spectroscopy (fNIRS). MATERIAL AND METHODS From November 2022 to March 2023, twenty-five patients with unilateral stroke were screened using computed tomography or magnetic resonance imaging and identified via a video fluoroscopic swallow study. Finally, patients were divided into rTMS (n=10) and iTBS (n=10) groups. Both groups received 2 weeks of stimulation on unaffected suprahyoid motor cortex. Surface electromyographic measured peak amplitude and swallowing time of bilateral suprahyoid muscles, and penetration-aspiration scale was assessed at baseline and after treatment. fNIRS monitored oxyhemoglobin beta values (OBV) in the primary motor, sensory, and bilateral prefrontal cortex (PFC). RESULTS Both groups showed significant improvements in penetration-aspiration scale, peak amplitude, and swallowing time, compared with baseline (P<0.001), and increased OBV in unaffected regions (P<0.05), especially PFC (P<0.001). No significant OBV increases were seen in affected regions (P>0.05). After treatment, OBV in the unaffected PFC was significantly higher than in the unaffected primary sensory and motor cortex regions for both groups (P<0.05). No significant differences were observed between groups in outcome measures (P>0.05). CONCLUSIONS rTMS and iTBS significantly improved swallowing function in unilateral stroke, relying on compensation by the unaffected cortex, particularly the PFC. iTBS may outperform rTMS by shortening treatment sessions and improving efficiency.

Multi-channel EMG manifestations of upper-extremity muscle coordination imbalance among community-dwelling sarcopenic seniors

BACKGROUND

Sarcopenia is an age-related, insidious, crippling but curable degenerative disease if diagnosed and treated early. However, no accessible and accurate early screening method is available for community settings that does not require specialized personnel. One of the hallmarks of sarcopenia is the pathological changes of muscle fiber type composition and motor unit firing patterns. Surface electromyography (sEMG) may serve as an effective tool for detecting differences between healthy and sarcopenic individuals due to its superior wearability and accessibility compared to other screening methods such as medical imaging and bioimpedance measurements, making it ideal for community-based sarcopenic screening. Our study aims to explore sEMG biomarkers that can be used for screening or diagnosis of sarcopenia.

RESULTS

We collected multi-channel sEMG signals from six forearm muscles of 98 healthy and 55 sarcopenic community-dwelling older adults. Participants performed grasp tasks at 20% and 50% of maximum voluntary contraction (MVC). Hexagons created by various EMG features, normalized with respect to respective MVC, and symmetry analyses were performed to estimate multi-muscle coordination patterns. An innovative index, namely incenter-circumcenter distance of muscle coordination (ICDMC), is proposed to discriminate between the healthy and sarcopenic groups. We utilized non-parametric tests to compare the ICDMC between the two groups, considering a p-value less than 0.05 statistically significant. The results showed that at 20% MVC, ICDMCs from root mean square (RMS), mean absolute value (MAV), slope sign changes (SSC) and wavelength (WL) showed statistically significant differences. More insights of this sEMG manifestation of sarcopenia were revealed by gender- and age-stratifications analyses.

CONCLUSIONS

Our results demonstrated that there are clear sEMG manifestations of altered muscle coordination in sarcopenic patients. More consistent force generation patterns were observed in the sarcopenic group, especially at lower contraction intensities. The novel ICDMC can quantify differences between sarcopenic and healthy muscle. These results warrant further research to further develop more accessible sarcopenia screening strategies in community settings based on electrophysiological measurements such as sEMG.

sEMG as complementary tool for VFSS: A synchronized study in patients with neurogenic oropharyngeal dysphagia

The neurogenic oropharyngeal dysphagia is a prevalent functional swallowing disorder resulting from neurological causes. The conventional diagnosis involves ionizing radiation in Videofluoroscopy Swallowing Studies (VFSS). Surface electromyography (sEMG) offers a non-invasive alternative by recording muscle activity. This research compares bolus passage timing through anatomical structures using VFSS and sEMG-related activation times. Fifty confirmed oropharyngeal dysphagia patients underwent synchronized VFSS and sEMG, evaluating muscle groups during cracker and fluid ingestion. sEMG revealed activation patterns in masseters, suprahyoid, and infrahyoid muscles, occurring before bolus passage through the mandibular line and concluding near the upper esophageal sphincter complex. sEMG identified differences in dysphagia severity (EAT-10 score), age, and diagnosis, contrasting VFSS results. Results indicate potential complementarity between sEMG and VFSS for dysphagia screening, diagnosis, and monitoring.

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

INTRODUCTION

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

METHOD

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

RESULTS

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

CONCLUSION

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

Effect of respiratory training on swallowing function in swallowing disorders: a systematic review and meta-analysis

PURPOSE

To determine the clinical efficacy of different respiratory training interventions on swallowing function in patients with swallowing disorders through the systematic review.

METHODS

We reviewed the literature regarding the application of respiratory training therapy in patients with swallowing disorders, followed by a PRISMA search of published literature in five databases (PubMed, Web of Science, The Cochrane Library, CINAHL and EMBASE) in December 2022. Two reviewers performed study selection, quality evaluation, and risk of bias, followed by data extraction and detailed analysis.

RESULTS

A total of six randomized controlled studies with a total sample size of 193 cases were included. Respiratory training improved swallowing safety (PAS (n = 151, SMD = 0.69, 95% CI - 1.11 to - 0.26, I2 = 36, p < 0.001)) and swallowing efficiency [residual (n = 63, SMD = 1.67, 95% CI - 2.26 to - 1.09, I2 = 23%, p < 0.001)] compared to control groups. The results of the qualitative analysis conducted in this study revealed that respiratory training enhanced hyoid bone movement but had no effect on swallowing quality of life.

CONCLUSIONS

Respiratory training interventions may improve swallowing safety and efficiency in patients with dysphagia. However, the level of evidence is low, and there is a limited amount of research on the effectiveness and physiology of this intervention to improve swallowing function. In the future, there is a need to expand clinical studies, standardize measurement tools, and improve study protocols.

Masseter and digastric muscle activity evaluation using a novel electromyogram that utilizes elastic sheet electrodes

PURPOSE

To evaluate the reproducibility and reliability of a novel electromyogram (EMG) device with a flexible sheet sensor for measuring muscle activity related to mastication and swallowing.

METHODS

We developed a new EMG device made of elastic sheet electrodes to measure the masseter and digastric muscle activities for evaluating mastication and swallowing. To examine the measurement reproducibility of the new EMG device, masseter muscle activity was analyzed using the intraclass correlation coefficient (ICC). Further, we measured the maximum amplitude, duration, integrated value, and signal-to-noise ratio (SNR) using the new EMG device and conventional EMG devices and evaluated the reliability using ICC and Bland-Altman analysis.

RESULTS

We confirmed high ICC (1,1) and ICC (2,1) scores (0.92 and 0.88, respectively) while measuring the reproducibility of the new EMG device. When compared to the active electrode EMG device, we found a high correlation for the maximum amplitude (0.90), duration (0.99), integrated values (0.90), and SNR (0.75), with no observation of significant fixed errors. Moreover, the regression coefficient was not significant for any of the evaluation items and no proportional error was observed. Compared with the passive electrode EMG device, the maximum amplitude and duration were highly correlated (0.73 and 0.89). In addition, the SNR exhibited a significant fixed error. In contrast, the regression coefficient was not significant for any of the evaluation items and no proportional error was observed.

CONCLUSIONS

Our results suggest that the new EMG device can be used to reliably and reproducibly evaluate muscle activity during mastication and swallowing.

Multi-Sensor Respiratory-Swallow Telecare System for Safe Feeding in Different Trunk Inclinations: System Development and Clinical Application

Proper positioning is especially important to ensure feeding and eating safely. With many nursing facilities restricting visitations and close contact during the coronavirus pandemic, there is an urgent need for remote respiratory-swallow monitoring. This study aimed to develop a semiautomatic feeding telecare system that provides instant feedback and warnings on-site and remotely. It also aimed to analyze the effects of trunk positions on respiratory-swallow coordination. A signal collector with multiple integrated sensors for real-time respiratory-swallow monitoring and warning was developed. A repeated measures design was implemented to evaluate the effects of trunk inclination angles on the swallow-related functions. Significant differences in inclination angles were discovered for swallowing apnea (p = 0.045) and total excursion time of thyroid cartilage (p = 0.037), and pairwise comparisons indicated that these differences were mostly present at 5° to 45°. Alerts were triggered successfully when undesired respiratory patterns or piecemeal occurred. The results indicated that a care recipient can swallow more easily when sitting upright (5°) than when leaning backward (45°). This telecare system provides on-site and remote respiratory-swallow monitoring and alerting for residents in care facilities and can serve as a pipeline for the early screening of swallowing dysfunction.

Synchronization between videofluoroscopic swallowing study and surface electromyography in patients with neurological involvement presenting symptoms of dysphagia

Introduction: Dysphagia is defined as the difficulty in transporting food and liquids from the mouth to the stomach. The gold standard to diagnose this condition is the videofluoroscopic swallowing study. However, it exposes patients to ionizing radiation. Surface electromyography is a non-radioactive alternative for dysphagia evaluation that records muscle electrical activity during swallowing. Objective: To evaluate the relationship between the relative activation times of the muscles involved in the oral and pharyngeal phases of swallowing and the kinematic events detected in the videofluoroscopy. Materials and methods: Electromiographic signals from ten patients with neurological involvement who presented symptoms of dysphagia were analyzed simultaneously with videofluoroscopy. Patients were given 5 ml of yogurt, 10 ml of water, and 3 g of crackers. Masseter, suprahyoid, and infrahyoid muscle groups were studied bilaterally. The bolus transit through the mandibular line, vallecula, and the cricopharyngeus muscle was analyzed in relation to the onset and offset times of each muscle group activation. Results: The average time of the pharyngeal phase was 0.89 ± 0.12 s. Muscle activation was mostly observed prior to the bolus transit through the mandibular line and vallecula. The end of the muscle activity suggested that the passage of the bolus through the cricopharyngeus muscle was almost complete. Conclusión: The muscle activity times, duration of the pharyngeal phase, and sequence of the muscle groups involved in swallowing were determined using sEMG validated with the videofluoroscopic swallowing study.

Effects of Carbonated Water Concentration on Swallowing Function in Healthy Adults

In this study, we investigated the effects of carbonated water concentration on swallowing function using surface electromyography (sEMG). Healthy subjects (n = 52, 26.77 ± 3.21 years old) were asked to perform two swallows each of noncarbonated water, low-concentration carbonated water, medium-concentration carbonated water, and high-concentration carbonated water. Onset time, the mean sEMG activity amplitude, and duration of muscle activity in each swallow were measured and analyzed for orbicularis oris, masseter, submental muscle complex and infrahyoid muscles. Onset time significantly decreased and mean sEMG activity amplitude significantly increased with carbonation concentration. Therefore, stimulation with carbonation can be effective for modulating a faster and stronger swallow in the oral and pharyngeal phases of swallowing, and its effect on amplitude was greater in the oral phase than in the pharyngeal phase.Clinical Trials Registration This study is registered with Clinical Research Information Service (KCT0005925).

Complementary combination of biomarkers for diagnosis of sarcopenia in C57BL/6J mice

AIMS

The objective of this study is to provide a reliable strategy for the diagnosis of sarcopenia based on a complementary combination of biomarkers from various approaches.

MATERIAL AND METHODS

A total of 30 C57BL/6J mice were used for the experiment, in which 15 young mice (YM) at 24 weeks old and 15 aged mice (AM) at 88 weeks old. Extracted features-based digital biomarkers from the electromyography activity of tibialis anterior muscles were evaluated by using receiver operating characteristic analysis. Extracted tissular proteins and circulating hormones based chemical biomarkers were investigated by using immunoblotting and enzyme-linked immunosorbent assay.

KEY FINDINGS

In terms of digital biomarkers, the feature-based classification of mice groups showed good performance (Feature A: AUC = 0.986, accuracy = 0.928) and (Feature B: AUC = 0.999, accuracy = 0.990). On the other hand, muscle-specific protein levels based chemical biomarkers (e.g. MuRF1, FoxO1, and perilipin2) were observed significantly increase with age. Pro-inflammatory cytokines based biomarkers extracted from muscle tissue and circulating plasma (e.g. TNF-α, IL-6, and IL-8) were significantly higher in case of AM group compared to YM group. Circulating hormone-based chemical biomarkers (e.g. cortisol/DHEA ratio and cathepsin D) presented a significant increase in concentrations with age. Circulating neurotransmitter based biomarkers (e.g. acetylcholine, serotonin, and histamine) also increased significantly in concentrations from YM to AM.

SIGNIFICANCE

A complementary combination of digital and chemical biomarkers covers multiple domains of sarcopenia to provide an effective strategy for the early diagnosis of sarcopenia.

Relationship between tongue pressure and handgrip strength: A systematic review and meta-analysis

OBJECTIVES

Muscle strength decreases with age, causing a decline in physical and oro-facial function. However, the impact of physiological and pathophysiological factors on tongue pressure (TP) has not been clarified. The purpose of this systematic review and meta-analysis was to compare and analyse TP and handgrip strength (HGS) between individuals aged <60 and ≥60 years, gender and need for care (independent older adults (IC) and older adults receiving nursing care (NC)). Furthermore, the effect of HGS in physical function on TP was examined.

METHODS

Human clinical studies reporting HGS and TP were searched systematically using PubMed and Ichushi-Web published from 1969 to Nov 2021. Random-effects meta-regressions were performed to compare between subgroups and to examine the association between HGS and TP (α < .05).

RESULTS

Forty-four studies with a total of 10 343 subjects were included. TP and HGS values were significantly higher in people aged <60 years relative to ≥60 years and in IC relative to NC (all p < .001). Regarding gender, there was no significant difference in TP (p = .370). However, a significant gender-dependent difference in TP was observed in people aged <60 years (p < .001), but not in aged ≥60 years in IC group (p = .118) and aged ≥60 years in NC group (p = .895). There was a significant positive correlation of HGS and TP (p < .001).

CONCLUSIONS

Similar to decrease in HGS, age-related sarcopaenia seems to have an effect on oro-facial muscles like the tongue. Research on rehabilitation measures for oro-facial muscle strength, similar to HGS might be beneficial to improve the personally acquired oro-facial potential.

Effects of Food and Liquid Properties on Swallowing Physiology and Function in Adults

Foods and liquids have properties that are often modified as part of clinical dysphagia management to promote safe and efficient swallowing. However, recent studies have questioned whether this practice is supported by the evidence. To address this, a scoping review was conducted to answer the question: "Can properties of food and liquids modify swallowing physiology and function in adults?" Online search in six databases yielded a set of 4235 non-duplicate articles. Using COVIDENCE software, two independent reviewers screened the articles by title and abstract, and 229 full-text articles were selected for full-text review. One-hundred eleven studies met the inclusion criteria for qualitative synthesis and assessment of risk of bias. Three randomized controlled trials and 108 non-randomized studies were analyzed. Large amounts of variability in instrumental assessment, properties of food and liquids, and swallowing measures were found across studies. Sour, sweet, and salty taste, odor, carbonation, capsaicin, viscosity, hardness, adhesiveness, and cohesiveness were reported to modify the oral and pharyngeal phase of swallowing in both healthy participants and patients with dysphagia. Main swallow measures modified by properties of food and liquids were penetration/aspiration, oral transit time, lingual pressures, submental muscle contraction, oral and pharyngeal residue, hyoid and laryngeal movement, pharyngeal and upper esophageal sphincter pressures, and total swallow duration. The evidence pooled in this review supports the clinical practice of food texture and liquid consistency modification in the management of dysphagia with the caveat that all clinical endeavors must be undertaken with a clear rationale and patient-specific evidence that modifying food or liquid benefits swallow safety and efficiency while maintaining quality of life.

Rehabilitation nutrition for individuals with frailty, disability, sarcopenic dysphagia, or sarcopenic respiratory disability

PURPOSE OF REVIEW

We describe the recent advances in rehabilitation nutrition, which is especially important for disabled or frail older individuals.

RECENT FINDINGS

Recent evidence pertaining to rehabilitation nutrition conducted in rehabilitation wards and acute care hospitals has been accumulating. The combination of rehabilitation nutrition and rehabilitation pharmacotherapy is important for eliciting higher functions. The 2020 update of the clinical practice guidelines for rehabilitation nutrition provides a weak recommendation for enhanced nutritional care for patients with cerebrovascular disease, hip fracture, cancer, or acute illness who are undergoing rehabilitation. Rehabilitation nutritional care process and the International Classification of Functioning, Disability and Health-Dietetics are used to implement high-quality rehabilitation nutrition. Aggressive nutrition therapy incorporates the daily energy expenditure plus daily energy accumulation to increase body weight and muscle mass. Preventing and treating sarcopenic dysphagia should include iatrogenic sarcopenia prevention and aggressive nutrition therapy. The diagnosis criteria for respiratory sarcopenia and sarcopenic respiratory disability have been established.

SUMMARY

The International Association of Rehabilitation Nutrition and Total Nutrition Therapy Rehabilitation program may contribute to international expansion of rehabilitation nutrition. Improving evidence-practice gaps in rehabilitation nutrition and increasing national health insurance coverage of aggressive nutrition therapy and rehabilitation nutrition teams are warranted.

Sarcopenic Dysphagia: A Narrative Review from Diagnosis to Intervention

Sarcopenia, defined as a decline in muscle mass and function related to aging, affects both limb and swallowing-related muscles. Sarcopenic dysphagia is characterized by decreased swallowing function; therefore, early detection of subclinical dysphagia and subsequent intervention appear to be crucial in the elderly. Numerous tools have been employed to measure the function, strength, and mass of swallowing-related muscles in sarcopenic elderly. The swallowing function can be evaluated by questionnaires like Eating Assessment Tool, Functional Oral Intake Scale, and Food Intake Level Scale, and tests such as the modified water swallowing test and videofluoroscopic swallowing study. Surface electromyography and high-resolution manometry can be applied for quantifying swallowing-related muscle strength. Modalities such as ultrasonography and magnetic resonance imaging are capable of estimating the swallowing muscle mass. In patients with sarcopenic dysphagia, a thorough assessment should be given followed by an integrated intervention combining swallowing muscle strengthening, nutrition support, food texture modification, physical, and occupational therapies. This article aimed to comprehensively summarize the diagnostic criteria/tools as well as their associations/performance in sarcopenic dysphagia. The intervention strategy will also be narrated in this review.

Diagnosis of Sarcopenic Dysphagia in the Elderly: Critical Review and Future Perspectives

Sarcopenic dysphagia (SD) is swallowing difficulty associated with loss of generalized skeletal muscles and swallowing-related muscles. Diagnostic criteria for SD were suggested, yet there is a variability in instruments and cut-offs used. The aim of the current review is to critically evaluate tools used in diagnosis of sarcopenic dysphagia in the elderly. Comprehensive review of the literature was performed. Studies were qualitatively evaluated for the diagnostic tools used to make a diagnosis of "sarcopenic dysphagia" and compared to the known diagnostic criteria for SD and other accepted measures. Fourteen studies (N = 10,282) were selected from a search yield of 331 de-duplicated studies. Ninety-three percent of studies (13/14) were conducted in Japan. All subjects included were over the age of 65 years old (mean, 76.5 years). Various tools were used to assess sarcopenia including handgrip strength (14/14 of studies), followed by skeletal muscle mass/index (7/14), tongue pressure, gait speed, and calf circumference in 5/14 studies. The most commonly tool used for dysphagia and/or swallowing dysfunction was the food level intake scale (5/14 of studies) followed by the functional oral intake scale (3/14). The 100-mL water swallow test was used in 2 of the 14 included SD studies. Fiberoptic endoscopic evaluation of swallowing, videofluoroscopic swallowing study, EAT-10 questionnaire, and standardized swallow assessment were each used in only one SD study. Further research is required to validate SD diagnostic tools, establish cut-offs in different populations, and investigate their role in screening of dysphagia and swallowing dysfunction in the elderly.

Effect of low tongue pressure on nutritional status and improvement of swallowing function in sarcopenic dysphagia

OBJECTIVES

This study aimed to evaluate the effect of low tongue pressure on the improvement of swallowing function in people with sarcopenic dysphagia and ongoing dysphagia or physical rehabilitation. In addition, we investigated whether sarcopenic dysphagia at admission was associated with severity of malnutrition.

METHODS

This was a prospective cohort study of 146 people with sarcopenic dysphagia (mean age 84.6 ± 7.4 y; 68.4% women, 31.6% men) in a postacute rehabilitation hospital. Sarcopenic dysphagia was defined as the presence of both sarcopenia and dysphagia but not neurogenic dysphagia, such as dysphagia due to stroke. Low tongue pressure was classified as "probable" and normal tongue pressure as "possible" sarcopenic dysphagia. Swallowing function was assessed using the Food Intake Level Scale. Malnutrition was diagnosed using the Global Leadership Initiative on Malnutrition criteria. Study outcomes included the amount of change in Food Intake Level Scale score during the rehabilitation period and the association between probable sarcopenic dysphagia and the severity of malnutrition on admission. Statistical significance was set at P < 0.05.

RESULTS

There were 83 participants (58.6%) with probable sarcopenic dysphagia. The severity of malnutrition (moderate malnutrition: adjusted odds ratio, 3.388; P = 0.042) and severe malnutrition (adjusted odds ratio, 3.663; P = 0.015) was a contributing factor to probable sarcopenic dysphagia. Probable sarcopenic dysphagia (regression coefficient, -0.384; P = 0.017) was negatively associated with the amount of change in Food Intake Level Scale score.

CONCLUSIONS

Probable sarcopenic dysphagia with low tongue pressure was associated with poorer improvement in swallowing function and severe malnutrition during postacute rehabilitation. Patients with probable sarcopenic dysphagia may require aggressive nutritional therapy.

Effect of Aging, Gender and Sensory Stimulation of TRPV1 Receptors with Capsaicin on Spontaneous Swallowing Frequency in Patients with Oropharyngeal Dysphagia: A Proof-of-Concept Study

Spontaneous swallowing contributes to airway protection and depends on the activation of brainstem reflex circuits in the central pattern generator (CPG). We studied the effect of age and gender on spontaneous swallowing frequency (SSF) in healthy volunteers and assessed basal SSF and TRPV1 stimulation effect on SSF in patients with post-stroke oropharyngeal dysphagia (OD). The effect of age and gender on SSF was examined on 141 healthy adult volunteers (HV) divided into three groups: GI-18-39 yr, GII-40-59 yr, and GIII->60 yr. OD was assessed by the Volume-Viscosity Swallowing Test (VVST). The effect of sensory stimulation with capsaicin 10^-5 M (TRPV1 agonist) was evaluated in 17 patients with post-stroke OD, using the SSF. SSF was recorded in all participants during 10 min using surface electromyography (sEMG) of the suprahyoid muscles and an omnidirectional accelerometer placed over the cricothyroid cartilage. SSF was significantly reduced in GII (0.73 ± 0.50 swallows/min; p = 0.0385) and GIII (0.50 ± 0.31 swallows/min; p < 0.0001) compared to GI (1.03 ± 0.62 swallows/min), and there was a moderate significant correlation between age and SFF (r = -0.3810; p < 0.0001). No effect of gender on SSF was observed. Capsaicin caused a strong and significant increase in SSF after the TRPV1 stimulation when comparing to basal condition (pre-capsaicin: 0.41 ± 0.32 swallows/min vs post-capsaicin: 0.81 ± 0.51 swallow/min; p = 0.0003). OD in patients with post-stroke OD and acute stimulation with TRPV1 agonists caused a significant increase in SSF, further suggesting the potential role of pharmacological stimulation of sensory pathways as a therapeutic strategy for CPG activation in patients with OD.

Diagnosis and Treatment of Sarcopenic Dysphagia: A Scoping Review

BACKGROUND

Sarcopenic dysphagia is a swallowing disorder due to sarcopenia involving the whole-body skeletal muscles and swallowing muscles. This scoping review aimed to explore the currently known information on the diagnosis and treatment of sarcopenic dysphagia and to clarify the types of research required to develop the field.

METHODS

We searched the PubMed, MEDLINE, CINAHL, and Cochrane databases from their inception to October 2020, using the search terms "(sarcopenia or sarcopenic or myopenia or dynapenia) and (dysphagia or swallowing or deglutition) and (diagnosis or treatment)". Articles reporting diagnosis method and treatment of sarcopenic dysphagia were included.

RESULTS

Twenty-one and eight articles reported on the diagnostic and treatment method, respectively. A diagnostic algorithm for sarcopenic dysphagia was most frequently used (n = 10). Other diagnostic methods included consensus diagnostic criteria for sarcopenic dysphagia (n = 4), sarcopenia and dysphagia without other causes of dysphagia (n = 4), and both sarcopenia and dysphagia (n = 3). The medical treatments for patients with sarcopenic dysphagia were described in single-patient case reports (n = 8) only. There were six articles reporting on a combination of rehabilitation and nutritional support. These reports showed the importance of interdisciplinary rehabilitation nutrition for improving patients' nutritional status and sarcopenia.

CONCLUSIONS

A reliable and validated diagnostic algorithm was the most widely used diagnostic method for sarcopenic dysphagia. Only case reports have been published for the medical treatment of patients with sarcopenic dysphagia. Interdisciplinary rehabilitation nutrition may be useful for treating patients with sarcopenic dysphagia.