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Background: Liquid modification is a widely established strategy of treatment for patients with dysphagia. The modification of liquid particularly by thickening or carbonation is a common approach to promote safe swallowing. Objective: This study sought to investigate how carbonated and/or thickened water modulates swallowing behaviours during swallowing in healthy young individuals. Methods: Thirty‐one healthy volunteers (9 men, 22 women; mean age ± standard deviation [SD], 25.7 ± 6.2 years) were instructed to swallow 20 mL of water, carbonated water and carbonated juice with and without added thickening agent. Electromyograms (EMGs) of the suprahyoid (S‐hyo) muscles were recorded to evaluate swallowing behaviours. Obtained S‐hyo EMG bursts was analysed using the following outcome parameters: onset latency, the time between swallowing que to onset of EMG burst; rising time and falling time, defined as the time between onset and peak, and between peak and offset, respectively; duration, defined as the time between onset and offset of EMG burst; and area integral value under the waveform. Results: Effects of thickening demonstrated the extended onset latency, EMG burst duration including falling time and the larger area of EMG in thickened liquid compared to thin liquid, but there was not much difference between thin and thickened carbonated liquids. Carbonation significantly decreased the duration including falling time for thickened but not for thin liquids. Conclusion: Patients with dysphagia can benefit from use of carbonated or thickened water while the effects on swallowing physiology may differ between carbonation and thickening. [ABSTRACT FROM AUTHOR]

Background: It remains unclear how the salivary flow and the fat content of food affect bolus formation during mastication. Objectives: We aimed to clarify: (1) how hyposalivation affects jaw‐closing and hyoid‐elevating muscle activities in bolus formation, and (2) if the effect of hyposalivation on muscle activity depends on the fat content of food. Methods: Eighteen healthy male volunteers were instructed to freely ingest four test foods: Plain, Fat without seasoning, Fat with seasoning, and Soft rice crackers. Masseter and suprahyoid electromyographic activities were recorded before and 30 min after the administration of atropine sulfate, a muscarinic receptor antagonist that induces hyposalivation. Results: Hyposalivation extended the masticatory duration significantly in all the test foods except Fat with seasoning. Masticatory cycle time was significantly longer with vs without hyposalivation for the Soft (p =.011). Suprahyoid activity/cycle was significantly greater with vs without hyposalivation (p =.013). Masticatory cycle time was significantly longer at the late stage with vs without hyposalivation for the Soft (p <.001). Suprahyoid activity/cycle was significantly greater at the middle (p =.045) and late stages (p =.002) with vs without hyposalivation for the Soft and greater at the late stage with vs without hyposalivation for the Plain (p =.043). Changes in masticatory cycle time and suprahyoid activity/cycle for these foods had significantly positive relationship (p <.001). Conclusion: Hyposalivation‐induced changes in masticatory behaviours resulted from the middle and late stage suprahyoid activity. Fat content and seasoning compensate for salivary flow inhibition. [ABSTRACT FROM AUTHOR]

Background: High‐density surface electromyography (HD‐sEMG) has enabled non‐invasive analysis of motor unit (MU) activity and recruitment, but its application to swallowing‐related muscles is limited. Objective: We aimed to investigate the utility of HD‐sEMG for quantitatively evaluating the MU recruitment characteristics of the suprahyoid muscles during tongue elevation. Methods: We measured the sEMG activity of the suprahyoid muscles of healthy participants during tongue elevation using HD‐sEMG. Maximum voluntary contraction (MVC) was measured, followed by data collection during sustained and ramp‐up tasks to capture suprahyoid muscle activity. Changes in the temporal/spatial MU recruitment patterns within individual suprahyoid muscles were analysed. Results: This study enrolled 16 healthy young adults (mean age: 27.8 ± 5.3 years; eight males and eight females). Increasing muscle force corresponded to a decrease in modified entropy and correlation coefficient and an increase in the coefficient of variation. No significant differences were observed between male and female participants. Conclusion: The results of this study, consistent with those observed in other muscles, such as the vastus lateralis muscle, suggest that HD‐sEMG is a valuable and reliable tool for quantitatively evaluating MU recruitment in the suprahyoid muscles. This measurement technique holds promise for novel assessments of swallowing function. [ABSTRACT FROM AUTHOR]

BACKGROUND: Modification of food consistency and volume is a commonly used method of swallowing compensation in clinical practice. Dry swallowing is a commonly used method of evaluation. The hyoid muscles are very important in swallowing. The effects of dry swallowing and swallowing tasks of different consistencies and volumes on hyoid muscle activation levels are still unclear. OBJECTIVE: To explore the effects of simple dry swallowing and swallowing tasks of different consistencies and volumes on the hyoid muscles in healthy adults. METHODS: A total of 44 healthy adults were included from April to August 2019, including 19 males and 25 females, with an average age of (21.7±2.8) years. They randomly performed dry swallowing and swallowing tasks of different consistencies (the International Dysphagia Diet Standardisation Initiative (IDDSI) frame levels 0-4) and volumes (5, 10, 20 mL), and the surface electromyogram signals of the hyoid muscles during each swallowing task were recorded. After processing the raw surface electromyogram signals, the activation levels of the hyoid muscles were compared between dry swallowing and swallowing tasks of different consistency and volume. RESULTS AND CONCLUSION: The mean amplitude values of the suprahyoid muscles corresponding to swallowing tasks of 20 mL for levels 0-4, 10 mL for level 3, and 5 mL for level 4 were higher than those of dry swallowing (P < 0.05). The mean amplitude values of the suprahyoid muscles corresponding to the 20-mL swallowing tasks of different consistencies were higher than those of the 5-mL swallowing tasks of the corresponding consistencies, except for level 3 (P < 0.05). The mean amplitude values of the suprahyoid muscles corresponding to the 20-mL swallowing tasks of different consistencies were higher than those of the 10-mL swallowing tasks of the corresponding consistencies, except for levels 2 and 3 (P < 0.05). The mean amplitude values of the infrahyoid muscles corresponding to all swallowing tasks were higher than that of dry swallowing (P < 0.05). The mean amplitude values of the infrahyoid muscles corresponding to the 20-mL swallowing tasks of different consistencies were higher than that of the 5- and 10-mL swallowing tasks of the corresponding consistencies (P < 0.05). The mean amplitude values of the infrahyoid muscles corresponding to the 10-mL swallowing tasks of different consistencies were higher than those of the 5-mL swallowing tasks of the corresponding consistencies, except for level 3 (P < 0.05). To conclude, in healthy adults performing swallowing tasks of different volumes and consistencies, the level of activation of the hyoid muscles is less susceptible to IDDSI frame levels 0-4 consistency and more susceptible to volume. The higher volume indicates the higher activation level of the hyoid muscles. [ABSTRACT FROM AUTHOR]

As one of the suprahyoid muscles, the digastric muscle is characterized by two separate bellies of different embryologic origins. The origin of the anterior belly is the digastric fossa, while the origin of the posterior belly is the mastoid notch. They share a common insertion: the intermediate tendon. When the digastric muscle contracts, the hyoid bone is raised. Opening of the jaw and swallowing of food boli are associated with digastric muscle activity. This review discusses the general anatomic features of the digastric muscle and its variation, primary functions, and clinical implications focused on surgical reconstruction and rejuvenation. [ABSTRACT FROM AUTHOR]

The stylohyoid muscle, one of the four suprahyoid muscles and one of the three styloid muscles, is a small thin muscle running from the styloid process to the hyoid bone. It is intimately related to the styloid process and the styloid ligament. It draws the hyoid bone superiorly and posteriorly along with the posterior belly of the digastric muscle. It functions mainly during swallowing and opening of the mandible. Clinically, it has received much attention for its association with Eagle's syndrome. In this review, anatomic considerations with clinical implications of the stylohyoid muscle will be covered. [ABSTRACT FROM AUTHOR]

BACKGROUND: Suprahyoid muscles behavior during the tongue lifting movement has not yet been elucidated. OBJECTIVE: The purpose of this study was to investigate the potential of elastography imaging to examine developmental oral dysfunction in children and oral hypofunction in older adults using sonography. METHODS: Tongue pressure was measured using a manometer with a probe. The tongue pressure was measured with simultaneously scanning the geniohyoid muscle (GHM) and the anterior belly of the digastric muscle (DGM) using sonographic elastography. Sagittal images of the GHM and coronal images of the DGM were used for the strain ratio measurement. The strain ratio of the muscles was measured three times for each subject with the tongue pressure values of 0–30 kPa. RESULTS: The strain ratio of the GHM were higher than those of the DGM at tongue pressure of 10, 20 and 30 kPa. The strain ratio of the GHM increased as the tongue pressure increased in all participants. In contrast, the strain ratio of the DGM tended to slowly decrease as tongue pressure increased in female participants. CONCLUSION: Sonographic elastography is useful for visual and quantitative evaluation of elastic properties in suprahyoid muscles during tongue lifting movements. [ABSTRACT FROM AUTHOR]

Background: It has not yet been clarified how the type of the chewing task affects related muscle activity and how the suprahyoid muscles contribute to masticatory function in humans. Objectives: This study aimed to investigate the difference in the suprahyoid muscle activity between the freely and unilaterally chewing tasks and between the working and non‐working sides during chewing. Materials and Methods: Twenty healthy volunteers were instructed to chew peanuts and two different types of rice crackers in two ways: freely and unilaterally while surface electromyograms of the masseter and suprahyoid muscles were recorded. The chewing duration, number of chewing cycles and chewing rate were compared between the tasks. Furthermore, the masseter and suprahyoid muscle activities per chewing cycle were compared between the sides. Results: The chewing duration was significantly longer, and the chewing rate was significantly higher during unilaterally chewing than freely chewing. The chewing duration differed significantly among the different foods; the harder the food, the longer the duration. Chewing rate and suprahyoid activity were significantly higher during soft rice cracker chewing. Masseter activity was higher on the chewing side than on the non‐chewing side while there was no difference in suprahyoid activity between the sides. Conclusion: The current results demonstrate a difference in the masticatory efficacy between the chewing tasks and a functional role of the suprahyoid muscles during chewing, which does not differ between the chewing and non‐chewing sides. [ABSTRACT FROM AUTHOR]

Background: A rise in tongue pressure coincides with an increase in the suprahyoid muscle activity. Objectives: The aim was to investigate the effects of holding a weighted plastic bottle on tongue pressure and the suprahyoid muscle activity. Methods: Eighteen participants (8 men and 10 women; mean age 42 ± 16 years) participated in this study. All participants had no history of speech, language, hearing or swallowing disorders and no tooth loss, and they did not require dentures. Healthy participants held gauzes connected with a plastic bottle with increasing resistive loads of 0 g, 250 g, 500 g and 750 g, between their palate and tongue. The maximum tongue pressure and average tongue pressure were measured during a 5 s hold. The average tongue pressure was defined as the mean tongue pressure data in each task. The suprahyoid muscle activity was measured using the electromyogram (EMG). The root mean square of the EMG signals measured while lifting different loads and while performing the head lifting exercises was compared. All variables were examined using the Friedman's test and Wilcoxon signed‐rank test. Results: The maximum tongue pressure (p <.05) and average tongue pressure values (p <.05) increased gradually in the anterior‐median region with increasing resistive loads, and the root mean square amplitudes for 250 g, 500 g and 750 g were not significant compared with head lifting exercises. Conclusion: These results indicated that plastic bottle holding could be a potential strength training tool for the tongue and the suprahyoid muscles. [ABSTRACT FROM AUTHOR]

Active pull of the suprahyoid muscle complex (SMC) was thought to be the main contributor of relapse in mandibular or chin advancement, but literature evidence lacks human studies that assess the role of the SMC following genial advancement (GeA). This study therefore aimed to analyse the influence of SMC pull on relapse following GeA by distraction osteogenesis based on electromyographic (EMG) changes. EMG was recorded and analysed preoperatively (T0), at four months (T1), and at one-year follow up (T2) at three submental regions during two different activities. The outcome variables were EMG changes of the SMC, and hard and soft tissue relapse. Assessment was carried out by comparison of EMG and lateral cephalograms taken at T0, T1, and T2. Ten patients (7 male and 3 female; median (SD) age 21.2 (3.99) years, range 18-28) were included. The EMG values revealed a statistically significant reduction between T0 and T1. T2 values were not higher than T0 during any activity. The results of Pearson's correlation demonstrated no significant relation between the amount of relapse and change in EMG values. This study concluded that active pull of the SMC is not the actual reason for skeletal relapse in chin or mandibular advancement. Passive biomechanics such as adnexial or muscular connective tissue, and paramandibular periosteum pull with native bone remodelling might be the prime reasons for relapse. However, further large sample studies are warranted to find the actual causes of relapse. [ABSTRACT FROM AUTHOR]

Recently, a therapeutic method to stimulate the suprahyoid muscle using peripheral magnetic stimulation for dysphagia rehabilitation has been reported. However, clinical evidence, application protocol, and intervention method remain unclear. Therefore, a systematic review of the published literature is needed. The objective of this study was to systematically review clinical studies of peripheral magnetic stimulation applied for rehabilitation of dysphagia. Issues to be considered in future studies are also suggested. This systematic review performed a literature search of four databases (Medline, Embase, CINAHL, and Web of Science) to identify relevant studies published on the application of repetitive peripheral magnetic stimulation (rPMS) for swallowing-related muscles between 2010 and 2022. Seven studies were reviewed. Randomized controlled trials and one-group pre–post, case study designs were included. In the included studies, rPMS was applied to strengthen the submental suprahyoid muscles. The intervention regime varied. The rPMS was applied at a frequency of 30 Hz for 2 s. Rest time ranged from 8 s to 27–28 s. The number of intervention sessions ranged from 2–3 to 30. The intensity ranged from pain-inducing minimum intensity (90% of maximum stimulus output) to non-painful intensity (70–80% of maximum intensity). The rPMS on the suprahyoid muscles had positive effects on physiological changes in the swallowing function, such as displacement of the hyoid bone, muscle strength (cervical flexor, jaw-opening force), swallowing safety, swallowing performance, and swallowing-related quality of life. Participants also reported little pain and adverse reactions during rPMS. Although rPMS is a therapeutic option that can help improve the swallowing function as a non-invasive stimulation method in the rehabilitation of dysphagia, clinical evidence is needed for the development of clear stimulation protocols and guidelines. [ABSTRACT FROM AUTHOR]

Sevoflurane-induced gasping in mice involves an enormous increase in inspiratory effort, mandibular movement, and a marked decrease in respiratory frequency (fR). We examined differences in breathing patterns and electromyogram activity (EMG SH ) of the suprahyoid muscles (SHMs) during eupnea under 3.2 % (1 MAC: minimum alveolar concentration) sevoflurane inhalation and sevoflurane-induced gasping under 6.5 % (2 MAC) sevoflurane inhalation in eight spontaneously breathing, tracheally intubated, adult mice. We found that the phasic EMG SH is obtained only during inspiration in eupnea and gasping and that integrated EMG SH increases more, as a percent of baseline (% baseline) than tidal volume (V T ) during gasping (median [interquartile range]; integrated EMG SH : 720 [425-1965] vs. V T : 300 [238-373], P < 0.05). We also found that the onset of EMG SH precedes the start of airflow while maintaining a bell-shaped EMG SH contour, which characterizes the EMG of upper airway dilator (UAD) muscles during eupnea and gasping. Vigorous respiratory-related mandibular movements were never observed during eupnea but were observed in seven of 8 mice during sevoflurane-induced gasping. Our observations indicate that SHMs act as a preferentially activating UAD muscle, contributing to the development of mandibular respiratory movements., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Purpose: High-density surface electromyography (HD-sEMG) allows non-invasive analysis of motor unit (MU) activity and recruitment. This study examines MU recruitment features as well as action potential using HD-sEMG in the suprahyoid muscles of patients with Parkinson's disease (PD) and assesses alterations caused by cervical percutaneous interferential current stimulation., Methods: Electrical activity of the suprahyoid muscles during tongue elevation was measured using HD-sEMG. Maximum voluntary contraction (MVC) was measured, then the modified entropy, coefficient of variation, correlation coefficient, and root mean square (RMS) were examined. For comparison, HD-sEMG was also conducted on healthy controls. In addition, this study assessed the impact of cervical percutaneous interferential current stimulation on HD-sEMG in patients with PD (Hoehn-Yahr stages 2-4) over 8 weeks., Results: Twenty-two patients with PD (mean age 71.7 ± 6.0, 7 females) and 14 healthy controls (mean age 74.9 ± 6.1, 7 females) were included. The RMS at 60 % MVC was significantly lower in patients with PD than in healthy controls (p = 0.007). After cervical percutaneous interferential current stimulation, the correlation coefficients at 40 % and 60 % MVC significantly decreased (p = 0.040 and p = 0.048, respectively), and the RMS at 60 % MVC significantly increased (p = 0.035)., Conclusion: HD-sEMG of the suprahyoid muscles showed characteristic findings in patients with PD and was able to detect subtle changes due to electrical stimulation intervention. Thus, HD-sEMG could be a promising tool for evaluating swallowing-related muscle conditions and interventions., Competing Interests: Declaration of competing interest HM received honoraria from Eisai, Shionogi, Otsuka Pharmaceutical, and Sumitomo Pharma. The other authors declare no competing interests., (Copyright © 2024. Published by Elsevier B.V.)

Due to the high prevalence of neck pain, considerable attention is paid to the function of cervical flexor muscles. Although the deep and superficial cervical flexor muscles have been evaluated, the impact of hyoid muscles on cervical flexion is still not well known. We, therefore, aimed to investigate the activation of hyoid muscles during physiological cervical flexion, and to determine the impact of different starting positions on cervical flexion muscle activation. The activities of bilateral sternocleidomastoid, scalene, suprahyoid, and infrahyoid muscles were evaluated by surface electromyography (EMG) in twenty young healthy volunteers. They performed a repetitive cervical flexion-extension movement, from neutral position of the head to the maximum flexion with the same speed set at eight seconds in a cycle, in three various positions (sitting, standing, and supine). In sitting and standing positions, the group of suprahyoid muscles was activated in advance of other cervical flexor muscles despite only significant differences were found in scalene muscles, and the activation of the group of infrahyoid muscles was time-synchronous with sternocleidomastoid muscles. On the other hand, in supine position, the activation of all measured cervical flexor muscles was significantly earlier and longer than in the other two positions. This study confirmed the empirical suggestion that hyoid muscles contributed to cervical flexion, and it confirmed that muscle activation was position dependent, even if the given movement is nearly identical. [ABSTRACT FROM AUTHOR]

It still remains unclear how the suprahyoid muscles function in bolus formation during mastication. This study aimed to investigate the contributory role of the suprahyoid muscles during mastication. A total of 20 healthy young volunteers were asked to perform tongue pressure generation tasks and unilateral mastication tasks using peanuts and two different types of rice crackers. Surface electromyographic (EMG) activity of the masseter and suprahyoid muscles and mandibular kinematics were recorded. Suprahyoid activity increased with increasing tongue pressure. Masticatory duration until the first deglutition differed significantly among the different foods; the harder the food, the longer the duration. This was also the case in masseter activity per masticatory cycle. Masticatory rate and suprahyoid activity per masticatory cycle were significantly higher during soft rice cracker mastication. Masseter activity was higher on the masticatory side than on the non-masticatory side, however, there was no difference in suprahyoid activity between the sides. Suprahyoid activity and jaw gape showed significant positive correlation in the early stage on both the masticatory and non-masticatory sides. The suprahyoid muscles functioned dominantly for jaw-opening during peanut mastication, and for bolus formation, especially in the late stage during soft rice cracker mastication. Bolus formation was performed dominantly on the masticatory side during rice cracker mastication. These findings clearly demonstrate a functional role of the suprahyoid muscles during mastication of solid foods from assessments using both EMG activity and mandibular kinematic recordings. [ABSTRACT FROM AUTHOR]

It still remains unclear how the suprahyoid muscles function in bolus formation during mastication. This study aimed to investigate the contributory role of the suprahyoid muscles during mastication. A total of 20 healthy young volunteers were asked to perform tongue pressure generation tasks and unilateral mastication tasks using peanuts and two different types of rice crackers. Surface electromyographic (EMG) activity of the masseter and suprahyoid muscles and mandibular kinematics were recorded. Suprahyoid activity increased with increasing tongue pressure. Masticatory duration until the first deglutition differed significantly among the different foods; the harder the food, the longer the duration. This was also the case in masseter activity per masticatory cycle. Masticatory rate and suprahyoid activity per masticatory cycle were significantly higher during soft rice cracker mastication. Masseter activity was higher on the masticatory side than on the non-masticatory side, however, there was no difference in suprahyoid activity between the sides. Suprahyoid activity and jaw gape showed significant positive correlation in the early stage on both the masticatory and non-masticatory sides. The suprahyoid muscles functioned dominantly for jaw-opening during peanut mastication, and for bolus formation, especially in the late stage during soft rice cracker mastication. Bolus formation was performed dominantly on the masticatory side during rice cracker mastication. These findings clearly demonstrate a functional role of the suprahyoid muscles during mastication of solid foods from assessments using both EMG activity and mandibular kinematic recordings.

Objective: To evaluate the contribution of suprahyoid muscles to mouth opening in different hyoid bone positions. Methods: The jaw-opening and closing movements were imposed on the 3D inverse dynamic jaw model with and without the lateral pterygoid muscle (LPM). The activation of the muscles was evaluated for eight different positions of the hyoid bone. Results: The muscles with 100% activation provided maximum mouth opening (MMO). When the hyoid bone was replaced, the muscles could achieve MMO at the 135º, 180º, and 225º points with the LPM. Mouth opening was estimated to be 36.8 mm in the absence of the LPM. A jaw opening greater than 36.8 mm was seen when the hyoid bone was repositioned at the 90º, 180º, and 135º points. Discussion: The contribution of suprahyoid muscles to mouth opening varies in different hyoid bone positions, with the inferior and anterior positions having a positive impact. [ABSTRACT FROM AUTHOR]

Introduction: the digastric muscle usually has two bellies, one anterior and one posterior, connected by an intermediate tendon. However, the presence of one or more accessory muscles present in the anterior belly of the digastric muscle has been widely reported in the literature over the years. These anatomical variations usually do not cause clinical symptoms, but they can make the interpretation of imaging tests difficult and lead to the occurrence of a wrong diagnosis, consequently, leading to unnecessary surgeries. The objective of this study was to report a rare accessory belly uniting the anterior bellies of the digastric muscle and to alert anatomical professionals about its morphology. During a dissection of a male human fetal cadaver at approximately 34 weeks of age, an accessory belly of trapezoid shape was found, connecting the anterior bellies of the digastric muscles. Its bundles initially had a parallel and oblique direction to later attach to the medial margin of the anterior belly of the right digastric muscle and its area was approximately 4.4 m² and a perimeter of 36.6 mm. Knowledge of the traditional and variational anatomy of the digastric muscle can be important for many procedures related to this region, including submandibulectomy, submental lipectomy, and rhytidectomy. [ABSTRACT FROM AUTHOR]

Recently, dysphagia associated with aging has become more a serious concern. The current study therefore sought to develop a novel method for evaluating swallowing function that focused on changes in the movement of swallowing-related organs, which slightly occur depending on swallowing conditions, using surface electromyography (sEMG) signals from the suprahyoid and infrahyoid muscles. A total of 15 elderly individuals without any history of dysphagia and 15 healthy young individuals were included herein. Initially, using two 22-channel electrodes, sEMG signals from suprahyoid and infrahyoid muscles were measured during the following four swallowing conditions, which combines two bolus volumes and two techniques: 1-mL normal swallow (NS1), 6-mL normal swallow (NS6), 1-mL effortful swallow (ES1) and 6-mL effortful swallow (ES6). sEMG signals from the suprahyoid and infrahyoid muscles were individually converted into swallowing pattern images. After extracting 8,192-dimensional feature vector from both images using the pretrained convolutional neural network AlexNet, feature vector was dimensionally compressed to three dimensions using kernel principal component analysis. Finally, we calculated the normalized Euclidean distance between each feature vector under different swallowing conditions and compared the differences in swallowing pattern changes between young and elderly individuals. Accordingly, our results found that significant differences in the normalized Euclidean distance NED(NS1, NS6) for normal swallowing at varying bolus volumes and in the normalized Euclidean distance NED(NS1, ES1), NED(NS6, ES6) at varying swallowing strengths. These significant differences between young and elderly individuals indicate differences in their ability to change swallowing patterns depending on swallowing conditions, and they may reflect an age-related decline in swallowing function. The evaluation of swallowing function using the proposed method could be applied to the early detection of reduced swallowing function or a state of frailty in aged individuals because it is noninvasive and can be performed at the bedside.

Examining the coordination of respiration and swallowing is important for elucidating the mechanisms underlying these functions and assessing how respiration is linked to swallowing impairment in dysphagic patients. In this study, we assessed the coordination of respiration and swallowing to clarify how voluntary swallowing is coordinated with respiration and how mastication modulates the coordination of respiration and swallowing in healthy humans. Twenty-one healthy volunteers participated in three experiments. The participants were asked to swallow 3 ml of water with or without a cue, to drink 100 ml of water using a cup without breathing between swallows, and to eat a 4-g portion of corned beef. The major coordination pattern of respiration and swallowing was expiration–swallow–expiration (EE type) while swallowing 3 ml of water either with or without a cue, swallowing 100 ml of water, and chewing. Although cueing did not affect swallowing movements, the expiratory time was lengthened with the cue. During 100-ml water swallowing, the respiratory cycle time and expiratory time immediately before swallowing were significantly shorter compared with during and after swallowing, whereas the inspiratory time did not differ throughout the recording period. During chewing, the respiratory cycle time was decreased in a time-dependent manner, probably because of metabolic demand. The coordination of the two functions is maintained not only in voluntary swallowing but also in involuntary swallowing during chewing. Understanding the mechanisms underlying respiration and swallowing is important for evaluating how coordination affects physiological swallowing in dysphagic patients.

Examining the coordination of respiration and swallowing is important for elucidating the mechanisms underlying these functions and assessing how respiration is linked to swallowing impairment in dysphagic patients. In this study, we assessed the coordination of respiration and swallowing to clarify how voluntary swallowing is coordinated with respiration and how mastication modulates the coordination of respiration and swallowing in healthy humans. Twenty-one healthy volunteers participated in three experiments. The participants were asked to swallow 3 ml of water with or without a cue, to drink 100 ml of water using a cup without breathing between swallows, and to eat a 4-g portion of corned beef. The major coordination pattern of respiration and swallowing was expiration–swallow–expiration (EE type) while swallowing 3 ml of water either with or without a cue, swallowing 100 ml of water, and chewing. Although cueing did not affect swallowing movements, the expiratory time was lengthened with the cue. During 100-ml water swallowing, the respiratory cycle time and expiratory time immediately before swallowing were significantly shorter compared with during and after swallowing, whereas the inspiratory time did not differ throughout the recording period. During chewing, the respiratory cycle time was decreased in a time-dependent manner, probably because of metabolic demand. The coordination of the two functions is maintained not only in voluntary swallowing but also in involuntary swallowing during chewing. Understanding the mechanisms underlying respiration and swallowing is important for evaluating how coordination affects physiological swallowing in dysphagic patients. [ABSTRACT FROM AUTHOR]

We investigated how swallowing behaviors are affected by the temperature and carbonation of water in healthy humans. Twenty-nine healthy volunteers were instructed to drink as much natural water, carbonated water, or cider as they wanted, and we recorded the volume of solution swallowed and electromyographic (EMG) activity of the masseter and suprahyoid muscles. Sensory tests regarding the ease of holding the solution in the mouth and ease of swallowing were also performed. The volume of carbonated water swallowed was significantly lower than that of natural water and cider. The ease of holding and swallowing the solution significantly differed between solution types such that natural water was the easiest solution to hold and swallow, followed by cider and then carbonated water in both tests. EMG activity was also affected by the solution type. Masseter EMG activity was significantly lower when swallowing natural water compared with carbonated water. Suprahyoid EMG activity was significantly lower when swallowing natural water compared with carbonated water and cider. The volume of solution swallowed was significantly correlated with the ease of holding and swallowing the solution, but not with masseter or suprahyoid EMG activities. The ease of holding and swallowing the solution significantly affected masseter and suprahyoid EMG activities. The results suggested that when participants experienced difficulty holding and swallowing the solution, masseter and suprahyoid EMG activity increased. Considering our findings that mechanical stimulation with bubbles decreased the volume of solution swallowed and increased EMG activities, carbonated water swallowing may be useful in treating deglutition disorders. [ABSTRACT FROM AUTHOR]

Recently, a therapeutic method to stimulate the suprahyoid muscle using peripheral magnetic stimulation for dysphagia rehabilitation has been reported. However, clinical evidence, application protocol, and intervention method remain unclear. Therefore, a systematic review of the published literature is needed. The objective of this study was to systematically review clinical studies of peripheral magnetic stimulation applied for rehabilitation of dysphagia. Issues to be considered in future studies are also suggested. This systematic review performed a literature search of four databases (Medline, Embase, CINAHL, and Web of Science) to identify relevant studies published on the application of repetitive peripheral magnetic stimulation (rPMS) for swallowing-related muscles between 2010 and 2022. Seven studies were reviewed. Randomized controlled trials and one-group pre–post, case study designs were included. In the included studies, rPMS was applied to strengthen the submental suprahyoid muscles. The intervention regime varied. The rPMS was applied at a frequency of 30 Hz for 2 s. Rest time ranged from 8 s to 27–28 s. The number of intervention sessions ranged from 2–3 to 30. The intensity ranged from pain-inducing minimum intensity (90% of maximum stimulus output) to non-painful intensity (70–80% of maximum intensity). The rPMS on the suprahyoid muscles had positive effects on physiological changes in the swallowing function, such as displacement of the hyoid bone, muscle strength (cervical flexor, jaw-opening force), swallowing safety, swallowing performance, and swallowing-related quality of life. Participants also reported little pain and adverse reactions during rPMS. Although rPMS is a therapeutic option that can help improve the swallowing function as a non-invasive stimulation method in the rehabilitation of dysphagia, clinical evidence is needed for the development of clear stimulation protocols and guidelines.

Due to the high prevalence of neck pain, considerable attention is paid to the function of cervical flexor muscles. Although the deep and superficial cervical flexor muscles have been evaluated, the impact of hyoid muscles on cervical flexion is still not well known. We, therefore, aimed to investigate the activation of hyoid muscles during physiological cervical flexion, and to determine the impact of different starting positions on cervical flexion muscle activation. The activities of bilateral sternocleidomastoid, scalene, suprahyoid, and infrahyoid muscles were evaluated by surface electromyography (EMG) in twenty young healthy volunteers. They performed a repetitive cervical flexion-extension movement, from neutral position of the head to the maximum flexion with the same speed set at eight seconds in a cycle, in three various positions (sitting, standing, and supine). In sitting and standing positions, the group of suprahyoid muscles was activated in advance of other cervical flexor muscles despite only significant differences were found in scalene muscles, and the activation of the group of infrahyoid muscles was time-synchronous with sternocleidomastoid muscles. On the other hand, in supine position, the activation of all measured cervical flexor muscles was significantly earlier and longer than in the other two positions. This study confirmed the empirical suggestion that hyoid muscles contributed to cervical flexion, and it confirmed that muscle activation was position dependent, even if the given movement is nearly identical.

Theta-burst stimulation (TBS), a variant of repetitive transcranial magnetic stimulation (rTMS), can potentially benefit the treatment of swallowing disorders. However, the after-effects of TBS on the swallowing motor cortex remain uncertain. The newly developed graph-based analysis of the centrality approach has been increasingly used to explore brain networks. The purpose of this study was to identify degree centrality (DC) alterations in the brain network after different TBS protocols were performed over the suprahyoid muscles motor cortex in healthy subjects. A total of 40 right-handed healthy subjects (mean age: 23.73 ± 2.57 years, range: 21–30, 20 females) were included in this study and randomly assigned to two groups, including the continuous TBS (cTBS) group and the intermittent TBS (iTBS) group. All of the subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning before and after TBS implementation. Compared to the baseline, cTBS resulted in increased DC values in the left inferior frontal gyrus (P < 0.01). In the iTBS group, decreased DC was observed in the left cerebellum and left medial frontal gyrus; However, increased DC was observed in several brain areas including the right superior temporal gyrus, right superior frontal gyrus, right postcentral gyri and left paracentral lobule (P < 0.01). These results indicated that cTBS mainly results in increasing DC in the ipsilateral. However, iTBS is capable of facilitating the excitability of the swallowing motor cortex and increasing the connectivity of multiple brain regions, including the bilateral sensorimotor network, and might have therapeutic potential in the treatment of swallowing disorders.

Background: Tongue lift movement (TLM) is used as a therapy to improve tongue pressure against the hard palate for dysphagic patients. Objective: The present study aimed to characterize the time‐dependent endurance changes in hyoid muscle activity and hyoid‐laryngeal displacement during TLM in different ways. Methods: Sixteen young healthy volunteers were instructed to perform TLM at maximum effort (100%) against the anterior and posterior parts of the hard palate using a balloon‐type tongue pressure instrument, followed by a 10‐second recording during anterior 80% TLM, anterior 100% TLM, posterior 80% TLM and posterior 100% TLM with visual feedback. Electromyography (EMG) of suprahyoid (S‐Hyo) and infrahyoid (I‐Hyo) muscles and videofluorography were simultaneously recorded. To evaluate temporal changes, the recording period was divided into three substages: early, middle and late. Tongue pressure, integrated EMG (iEMG), power frequency of EMG burst and hyoid‐laryngeal position were compared among the conditions (80% vs 100%, anterior vs posterior and early vs middle vs late). Results: Tongue pressure was stably maintained for 10 seconds in all conditions. S‐Hyo iEMG and I‐Hyo iEMG were significantly greater at 100% than at 80%, while no significant difference was observed between positions. S‐Hyo iEMG and I‐Hyo iEMG significantly increased at the late stage, while power frequency of EMG burst gradually decreased. Significant temporal changes in laryngeal elevation were observed only in posterior 100% TLM. Conclusion: The current results suggested that isometric posterior TLM may be more useful compared with anterior TLM in clinical situations for dysphagic patients to elevate the hyolaryngeal complex. [ABSTRACT FROM AUTHOR]

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

Theta-burst stimulation (TBS), a variant of repetitive transcranial magnetic stimulation (rTMS), can potentially benefit the treatment of swallowing disorders. However, the after-effects of TBS on the swallowing motor cortex remain uncertain. The newly developed graph-based analysis of the centrality approach has been increasingly used to explore brain networks. The purpose of this study was to identify degree centrality (DC) alterations in the brain network after different TBS protocols were performed over the suprahyoid muscles motor cortex in healthy subjects. A total of 40 right-handed healthy subjects (mean age: 23.73 ± 2.57 years, range: 21–30, 20 females) were included in this study and randomly assigned to two groups, including the continuous TBS (cTBS) group and the intermittent TBS (iTBS) group. All of the subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) scanning before and after TBS implementation. Compared to the baseline, cTBS resulted in increased DC values in the left inferior frontal gyrus (P < 0.01). In the iTBS group, decreased DC was observed in the left cerebellum and left medial frontal gyrus; However, increased DC was observed in several brain areas including the right superior temporal gyrus, right superior frontal gyrus, right postcentral gyri and left paracentral lobule (P < 0.01). These results indicated that cTBS mainly results in increasing DC in the ipsilateral. However, iTBS is capable of facilitating the excitability of the swallowing motor cortex and increasing the connectivity of multiple brain regions, including the bilateral sensorimotor network, and might have therapeutic potential in the treatment of swallowing disorders. [ABSTRACT FROM AUTHOR]

Induced contraction of the suprahyoid muscles via magnetic stimulation is considered to be effective for the rehabilitation of dysphagia. In our previous study, a magnetic stimulation coil with a U-shaped core for stimulating the suprahyoid muscles was developed based on the results of numerical analysis using a simplified human head model. It was confirmed that magnetic stimulation by the coil causes large contraction of the muscles. However, the human head has a complex structure that includes bone structures through which current cannot easily pass. To accurately predict the current density distribution induced by magnetic stimulation, a model that accurately describes the human head is required for numerical analysis. Therefore, in this study, numerical analysis using the finite element method with a human head model that includes the bone structure obtained from computed tomography scans was performed. The results for the model with bone structure show that the coil with a U-shaped core can stimulate the motor points of the suprahyoid muscles in the middle of the submental region. When compared with the current density observed in a model without the bone structure, that in the model with the bone structure was reduced by 29% at a point 20 mm below the mandibular surface. It is thus necessary to perform a numerical analysis using a model with the bone structure to obtain accurate analysis results. [ABSTRACT FROM AUTHOR]

• First reported study investigating the use of a device to aid swallowing in IBM. • EMST is not a restorative treatment for severe dysphagia in patients with IBM. • EMST may have some benefit to patients with a shorter duration of disease. Inclusion Body Myositis (IBM) is the most common acquired myopathy in older individuals with more than two thirds of patients experiencing impaired swallowing. There are currently no standardized exercise therapies to improve or sustain swallowing despite good evidence for exercise therapy in limb muscles. Reduced upper esophageal sphincter opening is a common abnormality associated with dysphagia in IBM. This pilot study recruited IBM patients with abnormal upper esophageal sphincter function and dysphagia into an exercise program. It was hypothesized that regular practice using the Expiratory Muscle Strength Trainer (EMST) device would improve hyolaryngeal movement by strengthening suprahyoid musculature and facilitate opening of the upper esophageal sphincter thereby improving swallowing and quality of life. Overall, IBM patients who used the EMST device demonstrated no improvement in swallowing function. Consistent with that result, there was also no change in measures of quality of life. However, further studies are needed to elucidate whether it has a preventative role in the development or progression of dysphagia in IBM as there is a suggestion that patients with a shorter duration of disease may have had some benefit. This research provides pilot data and recommendations that will guide future studies on exercise therapy and swallowing in this area. [ABSTRACT FROM AUTHOR]

Background: Tongue lift movement (TLM) task is considered a treatment strategy in dysphagic patients. However, there is no evidence of effect of sustained tongue movements on the related muscle contraction. Objectives: The present study aimed to characterise the properties and time‐dependent changes of the electromyographic (EMG) features of suprahyoid muscles during TLM. Methods: Twenty young healthy volunteers were instructed to perform TLM at maximum effort in either the anterior or the posterior position, during measurement of tongue pressure for 7 s. Supra‐ (S‐hyo) and infra‐hyoid (I‐hyo) EMGs were recorded. The area and power frequency of EMG burst and the area under the curve of tongue pressure were compared among the conditions: trials (1st, 2nd vs 3rd trials); anterior vs posterior TLM; and early vs late 3 s of each trial. Results: There was no difference in the tongue pressure among trials or between the early and late 3 s. Anterior tongue pressure was significantly higher than posterior tongue pressure (P <.001). The area of I‐hyo EMG burst was significantly larger (P =.044), and the power frequency of I‐hyo EMG burst was significantly smaller (P =.042) during posterior TLM than anterior TLM. A significant difference in the power frequency of both EMG bursts was observed between early and late stages during both anterior (P <.05) and posterior (P <.01) TLM. Conclusion: Hyoid muscles may compensate for rapid fatigue of the tongue muscle to maintain tongue pressure by changing their activity pattern during tongue pressure generation. [ABSTRACT FROM AUTHOR]

The activities of the suprahyoid muscles have been reported to be induced by tongue muscle contraction. The purpose of this research was to investigate whether tongue-strengthening exercises using a device cause hypertrophy of the geniohyoid muscle in healthy adults. Seven healthy young adults (3 men and 4 women, 21.0 ± 1.3 years old) received 8-week tongue muscle training with the JMS Tongue Pressure Measuring Device. The participants were instructed to press the anterior tongue against the hard palate 30 times in each session, three sessions a day, and 3 days a week. The exercise intensity was set to 60% of maximum tongue pressure in the first week, and to 80% of maximum tongue pressure for the remaining period. The training effect was evaluated by measuring (1) maximum tongue pressure value with the JMS Tongue Pressure Measuring Device, and (2) the area at rest, shortening amount, and contraction ratio of the geniohyoid muscle using ultrasonic imaging. After the 8-week training program, the maximum tongue pressure increased significantly from 44.9 to 61.6 kPa. The area of the geniohyoid muscle at rest also increased significantly from 2.3 to 2.6 cm2 after the program. There were no significant differences in the shortening amounts and the contraction ratios of the geniohyoid muscle between the values before and after the program. The tongue-strengthening exercise was useful to increase the muscle power of the geniohyoid, as well as the tongue muscles, in healthy young adults. [ABSTRACT FROM AUTHOR]

The hyoid bone is a small horseshoe-shaped bone located between the mandible and the shoulder girdle. It is classified as a sesamoid bone which means it is a freely floating bone. However, it is anything but freely floating. The hyoid bone is a vestigial structure and is found as part of the tongue in lower animal forms. The hyoid bone is attached to the base of the skull, the mandible, the tongue, the larynx, and the scapular belt. Even though the hyoid bone is an important structure, it has not received the attention that it deserves. It participates in the function of speech, respiration, mastication, and swallowing, as well as maintaining the patency of the airway between the oropharynx and the tracheal rings. Knowledge of the anatomy and physiology of the hyoid is necessary for recognition of the clinical presentation of related disorders and syndromes. [ABSTRACT FROM AUTHOR]

We present basic data on head positions that can serve as compensatory interventions for patients with weak tongue and buccinator muscles. We studied 30 Korean adults (15 males, 15 females; mean age, 23 years; range, 20-30 years). A TPS- 100 instrument was used to measure tongue and cheek pressures and suprahyoid and buccinator muscle activities at various head rotations and tilts, as independent variables. The data were subjected to one-way analysis of variance and post-hoc (linear contrast) testing. Tongue elevation pressures differed significantly when the head was flexed or extended compared to the neutral position (P<0.01). Suprahyoid muscle activity varied significantly when the head was rotated left or right compared to neutral, or tilted with the tongue elevated (P<0.01). Cheek pressure varied significantly when the head was rotated left or right compared to neutral, or tilted (P<0.01). Both tongue and cheek pressures increased significantly when the head was extended or rotated contralaterally compared to the neutral position. Suprahyoid muscle activity increased when the head was flexed or extended, or contralaterally or ipsilaterally rotated compared to the neutral position. Therefore, we suggest that head rotation or tilting could be used to vary oral pressure and muscle activity. [ABSTRACT FROM AUTHOR]

Aims: The purpose of this study was to evaluate swallowing changes in post-stroke patients with dysphagia after four weeks of suprahyoid muscles electrical stimulation. Methods: This was a prospective randomized study of early stage stroke patients with dysphagia. Electrical stimulation of suprahyoid muscles was given to a group of 54 patients (26 men, average age 70 years) for 20 minutes a day, 5 days a week. Standard orofacial rehabilitation without electrical stimulation was carried out on a control group of 54 patients (31 men, average age 69 years). Swallowing was evaluated at the beginning of the study and at the end, by videofluoroscopy - measuring the time for oral and pharyngeal phases. Results: The difference in duration of oral transit time (OTT) after the therapy between the study group (average: 0.55 ± 0.01) and the control group (average: 0.29 ± 0.03) was statistically significant (P=0.01). Difference in duration of the pharyngeal transit time (PTT) after the therapy between the study group (average: 0.37 ± 0.02) and control group (average: 0.15 ± 0.02) was also statistically significant (P=0.009). Conclusion: Electrical stimulation of suprahyoid muscles significantly reduced the duration of the oral and pharyngeal phases: in the post-stroke patients with dysphagia used in this study. The result is improved swallowing. This is a recently recommended approach and your study confirms its efficacy.

Interfaces based on surface electromyography (sEMG) signals are one of the important methods for non-invasively extracting the intention of a severely disabled person and supporting environmental control of wheelchairs and personal computers. However, sEMG-based interfaces generally have a common and maximum disadvantage of vulnerability to changes in electrode position. In this study, we aimed to develop a robust oral motion classification method that is robust to change in electrode position. Five healthy adult male subjects participated in this experiment. sEMG signals of the suprahyoid muscles during five oral motions (right, left, up tongue motion, jaw opening, and clenching) were measured using a boomerang-shaped 22-channel electrode adhered to the underside of the jaw. Oral motion classification from sEMG signals was performed using a support vector machine (SVM). When sEMG signals measured at a position different from the 22-channnel electrode position where the training data for SVM classifier was obtained were used as the test data, the classification accuracy of five oral motions sharply decreased from 92.0% to 72.8%. In contrast, when the 10 trials of sEMG signals obtained in advance at different electrode positions on different days were used as training data, the robustness against electrode position change was improved drastically and the mean classification accuracy of all subjects reached 90.4%. Furthermore, we developed an electric wheelchair control system that can operate based on classified motions and verified its usefulness for wheelchair operability and driving performance thorough the experiment. The results showed that the proposed method can omit the SVM training process required every time after the electrode is attached and can operate the wheelchair immediately after electrode attachment. Such advancement of interfaces eliminates the annoyance caused to the user who uses the interface on a daily basis and is expected to lead to an improvement in the quality of life.

Objectives: The aim of the present study is to evaluate the early and long-term postoperative dimensional changes of the muscles of the mandible in patients with orthognathic surgery for class II and class III malocclusions by using ultrasonography (US). Material and methods: Twenty-six patients who underwent bimaxillary orthognathic surgery for class II or class III malocclusions (14 and 12 patients, respectively) were ultrasonographically examined. The length, width, and cross-sectional area of the masseter and suprahyoid muscles were measured at three different time points: T0 (preoperatively), T1 (early postoperatively at 1 month after the surgery), and T2 (late postoperatively at 9 months). A repeated measures ANOVA was used to calculate statistically significant dimensional changes of the mandibular muscles. Results: Statistically significant dimensional changes were found postoperatively in class II malocclusion patients only. The digastric muscle showed higher values for the length and lower values for the width (p <.05) at T1. The geniohyoid muscles were higher in length at T1 and lower in cross-sectional area (CSA) (p <.05) at T2. A decreased measured length and an increased measured width were found in case of the mylohyoid muscle (p <.05) at T2. The early and long-term postoperative dimensional changes of the masseter muscle were not statistically significant. Conclusions: The mandibular muscles showed a variable adaptive response to the orthognathic surgery. US should be considered for the long-term follow-up of muscular dimensional changes in class II malocclusion patients. Clinical relevance: From a clinical perspective, US is a reliable, non-invasive, and widely available method, which allows monitoring the postoperative muscular changes occurring in class II malocclusion patients. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether chronic temporomandibular disorder (TMD) patients showed any changes in swallowing compared to a control group. Moreover, it was examined whether swallowing variables and a valid clinic measure of orofacial myofunctional status were associated. Material and methods: Twenty-three patients with chronic TMD, diagnosed with disc displacement with reduction (DDR) and pain, according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and 27 healthy volunteers (control group) were compared. Surface electromyography (EMG) of the temporalis, masseter, sternocleidomastoid, and suprahyoid muscles was performed during swallowing tasks of thin liquid (10 and 15 mL) and spontaneous saliva. Data were normalized. Results: Compared to the control group, TMD patients showed a prolonged duration of swallowing for liquid and saliva and required a longer time to reach the activity peak and half the integral. While the overall mean value of the relative peaks was similar for the groups, the suprahyoid peak was significantly lower in the TMD group during swallowing of liquid. Moreover, TMD patients recruited the jaw elevator muscles proportionally more than controls. The orofacial myofunctional status was moderately correlated with EMG parameters. Conclusion: Patients with chronic TMD showed temporal prolongation and changes in the relative activity of the muscles during the swallowing tasks. Clinical relevance: The present results contribute additional evidence regarding the reorganization of muscle activity in patients with chronic TMD. [ABSTRACT FROM AUTHOR]

Background: It has recently been shown that suprahyoid muscle exercise using kinesiology taping (KT) increases the activation of the suprahyoid muscle in healthy adults, suggesting a potential therapeutic clinical exercise for dysphagia rehabilitation. This study investigated the effect of dysphagia rehabilitation using KT in stroke patients with dysphagia. Methods: Thirty subjects in South Korea were enrolled in this prospective placebo-controlled double-blind study. Participants were randomly assigned to the experimental and sham groups. In the experimental group, the tape was attached to the hyolaryngeal complex, pulled downward with approximately 70% tension, and then attached to the sternum and the clavicle bilaterally. In the sham group, the tape was applied similarly but without the tension. Both groups performed voluntary swallowing 50 times (10 times swallowing per set, times 5 sets) a day for 4 weeks with KT applied. Outcome measures were assessed using portable ultrasound equipment. The parameter measured was the change in thickness of the tongue muscle, mylohyoid muscle, and the anterior belly of the digastric muscle. Results: The experimental group showed statistically significant changes in the thickness of the tongue muscle, mylohyoid muscle, and anterior belly of the digastric muscle than the sham group (p = 0.007, 0.002, and 0.001). Conclusion: Dysphagia rehabilitation using KT is a technique that may promote oropharyngeal muscle thickness in patients with dysphagia after stroke.

Objectives/hypothesis: Ultrasonography is an emerging clinical tool to study the dysfunction of swallowing muscles. This was the first sonographic study to assess the relationship between suprahyoid muscle contraction, hyoid bone displacement, and penetration-aspiration status (PAS) during swallowing in nasopharyngeal carcinoma (NPC) patients treated with radiotherapy (RT). The study also aimed to establish reliability data for the sonographic technique described.Study Design: Cross-sectional study.Methods: Geniohyoid muscle contraction was quantified using brightness-mode ultrasonography in this study of 40 post-RT NPC patients. A series of physiological parameters and PAS were measured using videofluoroscopy.Results: Intra- and inter-rater agreement values ranged from 0.75 to 0.96 across various sonographic measurements. Percentage increase in the cross-sectional area of the geniohyoid muscle correlated with anterior (r = 0.42, P < .05) but not superior (r = 0.27, P = .09) hyoid displacement. Anterior hyoid displacement and pharyngeal constriction ratio were significantly associated with PAS score.Conclusions: Sonographic measurement of suprahyoid muscles provides valuable information on muscle function and is potentially a useful clinical tool in swallowing assessment. Further research is needed to refine the role of this examination in dysphagia.Level Of Evidence: 2b. Laryngoscope, 2552-2559, 2018. [ABSTRACT FROM AUTHOR]

Surface electrical stimulation of the laryngeal region is used to improve swallowing in dysphagic patients. However, little is known about how electrical stimulation affects tongue movements and related functions. We investigated the effect of electrical stimulation on tongue pressure and hyoid movement, as well as suprahyoid and infrahyoid muscle activity, in 18 healthy young participants. Electrical stimulation (0.2-ms duration, 80 Hz, 80% of each participant's maximal tolerance) of the laryngeal region was applied. Each subject swallowed 5 ml of barium sulfate liquid 36 times at 10-s intervals. During the middle 2 min, electrical stimulation was delivered. Tongue pressure, electromyographic activity of the suprahyoid and infrahyoid muscles, and videofluorographic images were simultaneously recorded. Tongue pressure during stimulation was significantly lower than before or after stimulation and was significantly greater after stimulation than at baseline. Suprahyoid activity after stimulation was larger than at baseline, while infrahyoid muscle activity did not change. During stimulation, the position of the hyoid at rest was descended, the highest hyoid position was significantly inferior, and the vertical movement was greater than before or after stimulation. After stimulation, the positions of the hyoid at rest and at the maximum elevation were more superior than before stimulation. The deviation of the highest positions of the hyoid before and after stimulation corresponded to the differences in tongue pressures at those times. These results suggest that surface electrical stimulation applied to the laryngeal region during swallowing may facilitate subsequent hyoid movement and tongue pressure generation after stimulation. [ABSTRACT FROM AUTHOR]