Structural analysis of muscles elevating the hyolaryngeal complex

Effects of effortful swallowing against kinesiology taping resistance on the swallowing function in patients with poststroke dysphagia: A randomized controlled trial

BACKGROUND

A dysphagia rehabilitation method using kinesiology taping (KT) was recently introduced, and its potential for clinical efficacy was demonstrated by evaluating muscle activity and thickness. However, its effect on the swallowing function in patients with dysphagia remains unclear. This study aimed to investigate the effects of effortful swallowing against KT resistance on the swallowing function in patients with post stroke dysphagia.

METHODS

Thirty patients with poststroke dysphagia were recruited and randomly assigned to the experimental and placebo groups. In the experimental group, the KT was attached to the front of the neck (the hyoid bone between the sternum) with a tension of approximately 70% to 80%, and effortful swallowing was performed against the KT tension. In contrast, the placebo group performed effortful swallowing with KT applied at the same location without tension. The intervention was performed 30 times/day, 5 days/week for 6 weeks. The videofluoroscopic dysphagia scale (VDS) and penetration-aspiration scale (PAS) based on a videofluoroscopic swallowing study were used to analyze oropharyngeal swallowing function.

RESULTS

The experimental group showed statistically significant improvements in the oral and pharyngeal phases of the VDS (P = .029 and .007, respectively) and PAS (P = .034) compared with the placebo group. Effect sizes were observed for the oral (0.3) and pharyngeal phases (0.5) of the VDS and PAS (1.1).

CONCLUSION

This study demonstrated that effortful swallowing against resistance to KT is an effective therapeutic exercise for improving the swallowing function in patients with poststroke dysphagia.

Oral and Pharyngeal Dysphagia in Adults

Patients with oral and pharyngeal dysphagia have difficulty forming a cohesive bolus and/or transferring food from the mouth into the pharynx and esophagus to initiate the involuntary swallowing process. This may be accompanied by nasopharyngeal regurgitation, aspiration, and a sensation of residual food remaining in the pharynx. Abnormalities affecting the upper esophageal sphincter, pharynx, larynx, or tongue, in isolation or combination, result in oropharyngeal dysphagia affecting either or both transit and airway protection. These issues can be addressed with a combination of management of the underlying systemic disease, with surgical intervention or with swallow therapy.

Swallowing kinematics and submental muscles activation during a newly designed maneuver called Mouth Open Swallowing Maneuver: A comparative study

The aim of this study was to design a new maneuver called the Mouth Open Swallowing Maneuver (MOSM), and to compare swallowing kinematics and submental muscles activation (SMA) between MOSM and two current approaches used in dysphagia rehabilitation. Fifty healthy volunteers were asked to perform three repetitions of dry swallowing (DS) (control task), the MOSM, the Mendelsohn Maneuver (MM), and the Tongue-Hold Maneuver (THM) during videofluoroscopic swallowing study accompanied with simultaneous SMA recording. Swallowing kinematics were measured by frame-by-frame analysis on hyolaryngeal movement using ImageJ. Swallowing with maximum hyolaryngeal movement and SMA during these tasks was used for comparative analysis. Vertical movement of the hyoid during the MOSM was significantly greater than those observed during the DS and the THM (p<0.001, p<0.001). Horizontal movement of the hyoid during DS and the THM was significantly greater than that observed during the MM (p = 0.001, p = 0.001). Vertical movement of the larynx during the MOSM was significantly greater than those observed during DS, MM, and THM (p<0.001). There was no significant difference between tasks in horizontal movement of the larynx (p = 0.785). SMA during the THM was significantly greater than that observed during MOSM (p = 0.002). No significant difference was found between other tasks in terms of SMA (p>0.05). The MOSM as a newly designed maneuver was significantly superior to other maneuvers in increasing vertical hyolaryngeal movement. The THM has as much effect on hyolaryngeal movement as the MM. In this study, the MOSM was shown to be effective in increasing hyolaryngeal movement. ClinicalTrials.gov Protocol Registration and Results System (PRS); the clinical trial registration number (NCT05579041).

Chewing Well Modulates Pharyngeal Bolus Transit During Swallowing in Healthy Participants

Mastication is controlled by central pattern generator in the brainstem and can be modulated by volition. The aim of this study was to investigate the effect of chewing well on swallowing. Twenty-six healthy participants were instructed to eat 8, 12, and/or 16 g of steamed rice with barium sulphate under the following two conditions: chewing freely task (CF; chewing naturally in their usual manner) and chewing well task (CW; chewing the food with a request to "chew well"). We evaluated bolus transport and swallowing movement using videofluoroscopy and electromyography of the masseter, suprahyoid and thyrohyoid muscles. The chewing time and pharyngeal transit time (PTT) at the first swallow showed high reproducibility in both CF and CW. PTT for CW was significantly shorter and longer than CF in 12 and 16 g, respectively. In 12 g, CW increased the pharyngeal bolus velocity and decreased thyrohyoid EMG activity during swallowing compared with CF. In 16 g, the difference between CW and CF in the estimated swallowed bolus volume was positively correlated with that in upper esophageal sphincter transit duration. We speculate that CW modulates PTT during swallowing depending on the mouthful volume.

Effects of suprahyoid muscle strengthening exercise using kinesiology taping on muscle activation and thickness in community-dwelling elderly: A randomized controlled trial

BACKGROUND

Recently, swallowing resistive exercise using kinesiology taping (KT) has been reported as a novel method for dysphagia rehabilitation However, clinical evidence is still unclear, and effects in the elderly have not been confirmed.

OBJECTIVE

This study aimed to investigate the effects of suprahyoid muscle strengthening exercise using KT on muscle activation and thickness in community-dwelling elderly.

METHODS

A total of 24 healthy older people were enrolled in this study and randomly assigned to an experimental group and a placebo group. In the experimental group, KT was attached to the front of the neck with a tension of about 70% to 80%, and a resistive swallowing exercise was performed. In the placebo group, the tape was applied similarly but without tension. Both groups performed resistive swallowing exercises 10 times a day (50 swallows per day) for 6 weeks. The activation and thickness of the suprahyoid muscles were measured using portable ultrasound equipment and an surface electromyelograph device.

RESULTS

The experimental group showed a significant increase in suprahyoid muscle activation (mean and peak) and muscle thickness (digastric and mylohyoid) than the placebo group (all, P < .05).

CONCLUSION

This study confirmed that suprahyoid muscle strengthening exercise using KT had a positive effect on the suprahyoid muscles in healthy older adults, thus suggesting the possibility of a therapeutic exercise method for dysphagia rehabilitation.

Chemodenervation of the Posterior Belly of the Digastric Muscle in Facial Synkinesis

Background: Patients with facial synkinesis may have jaw tightness and swallow discomfort despite chemodenervation of facial mimetic musculature, and the posterior belly of the digastric (PBD) muscle is a logical target to treat these symptoms. Learning/Study Objective: To compare patient-reported outcomes of botulinum toxin (BT) chemodenervation of the posterior belly of digastric muscle in patients with postparalytic facial synkinesis. Design Type: Retrospective review. Methods: Patients with facial synkinesis who underwent electromyography (EMG)-guided PBD BT chemodenervation in addition to their baseline therapeutic regimen were included. Pre- and post-treatment Synkinesis Assessment Questionnaires (SAQ) and a two-question survey regarding jaw tightness and swallow discomfort were administered. Results: Twenty-nine patients were included. An average of 5 U of BT-A was injected into the PBD, and 46.5 U across all facial muscles. From pre- to post-injection, patients demonstrated improvement in jaw tightness at rest (3.02 vs. 1.98/5.0, p < 0.001), with swallow (2.78 vs. 1.94/5.0, p < 0.001), and total SAQ (64.3 vs. 51.2/100, p < 0.001). Patients rated subjective benefit from PBD injection compared with prior treatments without PBD injection as 4.5/5.0. Conclusion: Synkinesis patients with jaw tightness or swallow discomfort may benefit from the addition of PBD injections to the therapeutic regimen.

Quantifying Pharyngeal Residue Across the Adult Life Span: Normative Values by Age, Gender, and Swallow Task

PURPOSE

We quantified pharyngeal residue using pixel-based methods in a normative data set, while examining influences of age, gender, and swallow task.

METHOD

One hundred ninety-five healthy participants underwent a videofluoroscopic swallow study following the Modified Barium Swallow Impairment Profile (MBSImP) protocol. ImageJ was used to compute Normalized Residue Ratio Scale and the Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) pharyngeal residue measures. Reliability was established. Descriptive statistics were performed for all residue measures. Inferential statistics were performed using ASPEKT total scores (i.e., %C2-42). Logistic regression models explored predictors of residue versus no residue. Generalized linear mixed models explored predictors of nonzero residue. Spearman rho explored relationships between ASPEKT total residue scores and MBSImP Component 16 (Pharyngeal Residue) scores.

RESULTS

Majority of swallows (1,165/1,528; 76.2%) had residue scores of zero. Residue presence (%C2-42 > 0) was influenced by age (more in older [F = 9.908, p = .002]), gender (more in males [F = 18.70, p < .001]), viscosity (more in pudding, nectar, and honey [F = 25.30, p < .001]), and volume (more for cup sip [F = 37.430, p < .001]). When residue was present (363/1,528 = 23.8%), amounts were low (M = 1% of C2-42, SD = 2.4), and only increasing age was associated with increased residue (F = 9.008, p = .007) when controlling for gender and swallow task. Increasing residue was incremental (0.01% of C2-42 per year). As ASPEKT total residue values increased, MBSImP Component 16 scores also increased.

CONCLUSIONS

Pharyngeal residue amounts were very low in healthy adults. Residue presence can be influenced by age, gender, and swallow task. However, when present, the amount of pharyngeal residue was only associated with increasing age.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21957221.

Evaluation of morphological features of palatopharyngeus insertion into the thyroid cartilage

The attachment of the palatopharyngeus extended from the posterior end of the thyroid cartilage to the posterior margin of the inferior constrictor attachment that might contribute to successive swallowing movements. Laryngeal elevation is essential for proper swallowing and breathing. Recently, clinical research has demonstrated that the palatopharyngeus, a longitudinal muscle of the pharynx, is involved in the elevation of the larynx. However, the morphological relationship between the larynx and palatopharyngeus remains unclear. In the present study, we analyzed the attachment site and characteristics of the palatopharyngeus in the thyroid cartilage. We evaluated 14 halves of seven heads from Japanese cadavers (average age: 76.4 years); 12 halves, anatomically and two halves histologically. A part of the palatopharyngeus, which originated from the inferior aspect of the palatine aponeurosis, was attached to the inner and outer surfaces of the thyroid cartilage through collagen fibers. The attachment area extends from the posterior end of the thyroid cartilage to the posterior margin of the attachment site of the inferior constrictor. The palatopharyngeus may elevate the larynx with the suprahyoid muscles and contribute to successive movements of swallowing with surrounding muscles. Based on our findings and previous studies, palatopharyngeus with various muscle bundle directions may be essential for the coordination of continuous swallowing events.

Absent epiglottic inversion as seen on flexible endoscopic evaluations of swallowing (FEES) is associated with a gestalt reduction in swallowing mechanics

PURPOSE

Epiglottic inversion, which provides one layer of the requisite protection of the airway during swallowing, is dependent on a number of biomechanical forces. The aim of this study was to examine the association between swallowing mechanics, as visualized during a Modified Barium Swallow (MBS) exam, and the rating of epiglottic inversion as seen on Flexible Endoscopic Evaluation of Swallowing (FEES).

METHODS

This study analyzed twenty-five adult outpatients referred for a simultaneous FEES/MBS exams. Each participant swallowed a 5 mL thin liquid bolus, which was the bolus size analyzed for this study's question. Epiglottic inversion, as seen on FEES, was rated by three independent raters. Additionally, twelve swallowing landmarks tracked the shape change of each participant's swallow on the MBS video using a MatLab-specific tracking tool. Analyses were run to determine mean differences in swallowing shape change between the swallows across 3 groups: complete, reduced, and absent epiglottic inversion, as seen on FEES. Using a Computerized Analysis of Swallowing Mechanics (CASM), canonical variate analyses and discriminant function testing were carried out. Other swallowing mechanics were also analyzed for kinematic movements to isolate the function of the hyoid and larynx. A two-sample t-test was conducted to compare mean hyolaryngeal movement between complete and incomplete epiglottic inversion groups.

RESULTS

Overall swallowing shape changes were statistically significantly different between the absent, reduced, and complete epiglottic inversion groups on FEES. Canonical variate analyses revealed a significant overall effect of shape change between the groups (eigenvalue = 2.46, p < 0.0001). However, no statistically significant differences were found on hyoid excursion (p = 0.37) and laryngeal elevation (p = 0.06) kinematic measurements between patients with complete and incomplete epiglottic inversion on FEES.

CONCLUSION

Epiglottic inversion on FEES is a valuable rating that infers reduced range of motion of structures that cannot be seen on FEES. This small sample of patients suggests that FEES ratings of absent epiglottic inversion may represent gestalt reduction in swallowing mechanics.

The association between muscle architecture and muscle spindle abundance

Across the human body, skeletal muscles have a broad range of biomechanical roles that employ complex proprioceptive control strategies to successfully execute a desired movement. This information is derived from peripherally located sensory apparatus, the muscle spindle and Golgi tendon organs. The abundance of these sensory organs, particularly muscle spindles, is known to differ considerably across individual muscles. Here we present a comprehensive data set of 119 muscles across the human body including architectural properties (muscle fibre length, mass, pennation angle and physiological cross-sectional area) and statistically test their relationships with absolute spindle number and relative spindle abundance (the residual value of the linear regression of the log-transformed spindle number and muscle mass). These data highlight a significant positive relationship between muscle spindle number and fibre length, emphasising the importance of fibre length as an input into the central nervous system. However, there appears to be no relationship between muscles architecturally optimised to function as displacement specialists and their provision of muscle spindles. Additionally, while there appears to be regional differences in muscle spindle abundance, independent of muscle mass and fibre length, our data provide no support for the hypothesis that muscle spindle abundance is related to anatomical specialisation.

Toward a robust swallowing detection for an implantable active artificial larynx: a survey

Total laryngectomy consists in the removal of the larynx and is intended as a curative treatment for laryngeal cancer, but it leaves the patient with no possibility to breathe, talk, and swallow normally anymore. A tracheostomy is created to restore breathing through the throat, but the aero-digestive tracts are permanently separated and the air no longer passes through the nasal tracts, which allowed filtration, warming, humidification, olfaction, and acceleration of the air for better tissue oxygenation. As for phonation restoration, various techniques allow the patient to talk again. The main one consists of a tracheo-esophageal valve prosthesis that makes the air passes from the esophagus to the pharynx, and makes the air vibrate to allow speech through articulation. Finally, swallowing is possible through the original tract as it is now isolated from the trachea. Yet, many methods exist to detect and assess a swallowing, but none is intended as a definitive restoration technique of the natural airway, which would permanently close the tracheostomy and avoid its adverse effects. In addition, these methods are non-invasive and lack detection accuracy. The feasibility of an effective early detection of swallowing would allow to further develop an implantable active artificial larynx and therefore restore the aero-digestive tracts. A previous attempt has been made on an artificial larynx implanted in 2012, but no active detection was included and the system was completely mechanic. This led to residues in the airway because of the imperfect sealing of the mechanism. An active swallowing detection coupled with indwelling measurements would thus likely add a significant reliability on such a system as it would allow to actively close an artificial larynx. So, after a brief explanation of the swallowing mechanism, this survey intends to first provide a detailed consideration of the anatomical region involved in swallowing, with a detection perspective. Second, the swallowing mechanism following total laryngectomy surgery is detailed. Third, the current non-invasive swallowing detection technique and their limitations are discussed. Finally, the previous points are explored with regard to the inherent requirements for the feasibility of an effective swallowing detection for an artificial larynx. Graphical Abstract.

Characteristics of submental muscles function and hyoid bone movement in patients with dysphagia after stroke

BACKGROUND

Dysphagia is one of the common complications after stroke. Dysphagia significantly increases the probability of serious adverse consequences. The purpose of this study was to compare the characteristics of submental muscles electromyography and hyoid motion parameters between patients with dysphagia after stroke and healthy controls, and whether there is a synergistic effect between the function of the submental muscles and the movement of the hyoid.

METHODS

Fifteen patients with post-stroke dysphagia and fifteen healthy adults simultaneously underwent the videofluoroscopic and surface electromyography of the submental muscles while swallowing 5 ml of concentrated liquid barium sulphate. The electromyographic signal of the submental muscles was analysed along with parameters of hyoid movement.

FINDINGS

Stage transition duration and duration of surface electromyographic activity were extended significantly in post-stroke dysphagia patients(P < 0.05). Surface electromyography amplitude and hyoid movement were significantly reduced in patients (P < 0.05). There was a significant correlation between the maximum hyoid movement distance and the peak sEMG amplitude in healthy controls (r = 0.660, P = 0.014), but not in patients with dysphagia after stroke (r = 0.425, P = 0.148).

INTERPRETATION

Submental muscles electromyographic signal changes in patients may be the result of uncoordinated muscle contractions and decreased muscle strength. Furthermore, the reduced hyoid movement distance may be due to impaired function of the submental muscles. In addition, the submental muscles and hyoid movement or other swallowing structures functions were impaired to varying degrees, resulting in the disappearance of the correlation between the maximum movement distance of the hyoid and the peak amplitude.

Reliability of Ultrasound Examination of Hyoid Bone Displacement Amplitude: A Systematic Review and Meta-Analysis

In swallowing, the hyoid bone moves up and forward in response to the activation of suprahyoid muscles, opening the upper esophageal sphincter and aiding the airway protection mechanism. This displacement measure has been analyzed with ultrasound images because this method does not expose the patient to radiation, has a good cost-benefit ratio, and is safe for the patient. However, there is no consensus on the reliability of this ultrasound measure. The objective of this study was to analyze the reliability of measuring hyoid bone displacement amplitude in swallowing with ultrasound. The systematic review encompassed five databases (MEDLINE, Scopus, EMBASE, Web of Science, Cochrane Library) and gray literature. There was no limitation of language or year of publication. The search/selection/extraction methodology was conducted by two authors blindly and independently, and differences were solved by a third rater. Three studies met the eligibility criteria: two of them analyzed the reliability in non-dysphagic populations and the other, in dysphagic patients. The transducer was positioned in the submandibular region in all studies. The authors were not clear about the training time to acquire and analyze ultrasound images. The meta-analysis had an interrater reliability of 0.858 (95% CI: 0.744-0.924) and intrarater reliability of 0.968 (95% CI: 0.903-0.990). There was, however, heterogeneity of p = 0.005 for intrarater reliability. Despite good reliability, the heterogeneity reinforces the importance of training and protocol standardization for image acquisition and analysis.

Determining Swallowing Biomechanics Underlying Modified Barium Swallow Impairment Profile Scoring Using Computational Analysis of Swallowing Mechanics

PURPOSE

The elements of impaired swallowing biomechanics are visually assessed and scored by clinicians using a standardized and validated tool for assessing type and severity of physiological impairments using the Modified Barium Swallow Impairment Profile (MBSImP). However, the functional anatomical correlates that underly noted impairments using MBSImP scoring have not been measured. The purpose of this study was to determine whether differences in MBSImP component scores represent differences in underlying swallowing mechanics as measured by computational analysis of swallowing mechanics (CASM) to better define underlying mechanisms of impairment.

METHOD

A retrospective analysis of modified barium swallow studies from physician-referred adult patients with dysphagia was scored using the MBSImP for laryngeal elevation, anterior hyoid excursion, epiglottic movement, pharyngoesophageal segment opening, and tongue base retraction. A canonical variate analysis (CVA) was performed to determine the movement of anatomical landmarks associated with MBSImP component scores using the CASM method. Mahalanobis distances (D) were then used to detect differences among MBSImP scores for each component assessed.

RESULTS

CVA showed significant differences (p < .0001) in Mahalanobis distance (D > 1) between MBSImP component scores of 0-1, 0-2, 0-3, or 0-4, as applicable, depending on the component. Discriminant function analyses revealed concomitant increase/worsening in MBSImP score with changes in anatomical positioning of structures.

CONCLUSIONS

Ratings of swallowing impairment and physiology using the MBSImP have distinct biomechanical correlates with anatomical movements of swallowing. These data further demonstrate how swallowing mechanics are highly interrelated. Understanding these linkages between anatomical and physiological movement within impaired swallowing biomechanics is essential in more specific characterization and treatment of dysphagia.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20816788.

Quantification of the Swallowing Mechanism Through Muscle Synergy Analysis

Decreased swallowing function increases the risk of choking and aspiration pneumonia. Videofluoroscopy and computed tomography allow for detailed observation of the swallowing movements but have radiation risks. Therefore, we developed a method using surface electromyography (sEMG) to noninvasively assess swallowing function without radiation exposure. A 44-channel flexible sEMG sensor was used to measure the sEMG signals of the hyoid muscles during swallowing in 14 healthy young adult and 14 elderly subjects. Muscle synergy analysis was performed to extract the muscle synergies from the sEMG signals, and the three synergies were extracted from the hyoid muscle activities during the swallowing experiments. The experimental results showed that the three synergies represent the oral, early pharyngeal, and late pharyngeal swallowing phases and that swallowing strength is tuned by the strength of the muscle activities, whereas swallowing volume is controlled by adjusting muscle activation timing. In addition, the timing of the swallowing reflex is slower in elderly individuals. The results confirm that the proposed approach successfully quantifies swallowing function from sEMG signals, mapping the signals to the swallowing phases.

Oropharyngeal Capsaicin Exposure Improves Infant Feeding Performance in an Animal Model of Superior Laryngeal Nerve Damage

Sensorimotor feedback is critical to safe and effective swallowing. Because of this, sensory interventions have the potential to treat dysphagia. One such treatment may be found in capsaicin, which activates the internal branch of the superior laryngeal nerve (iSLN). The iSLN initiates the pharyngeal swallow, and a more sensitive iSLN should more readily elicit swallowing and improve swallow safety. We explored the neurophysiological mechanism by which capsaicin improves swallow performance using an infant pig model with a unilateral iSLN lesion. Using high-speed videofluoroscopy, we collected oropharyngeal kinematic data while pigs suckled on bottles, before and after applying capsaicin to the posterior tongue and valleculae. We found that capsaicin application decreased maximal bolus sizes, which improved swallow safety. Furthermore, capsaicin improved performance when infant pigs swallowed more moderately sized boluses. However, capsaicin did not change swallow frequency, the number of sucks prior to each swallow, nor total pharyngeal transit time (TPT). Similarly, excursions of the hyoid, thyroid, and posterior tongue were unchanged. TPT and hyoid and thyroid excursions maintained relationships with bolus size post-capsaicin, suggesting that these variables are less sensitive to sensory intervention. The timing and extent of posterior tongue movement were only correlated with bolus size pre-capsaicin, which could imply that capsaicin fundamentally changes in relationships between tongue movements and bolus size. Our results provide insight into the neural control of swallowing and capsaicin's mechanism of action, and suggest that capsaicin may be beneficial in treating acute infant dysphagia.

Effects of Respiratory Muscle Strength Training on Respiratory-Related Impairments of Parkinson's Disease

In addition to typical motor dysfunction, Parkinson's disease is also characterized by respiratory-related dysfunction. As a means of rehabilitation, respiratory muscle strength training (RMST) has been applied to restore Parkinson's disease (PD) functions. However, the current clinical value of RMST in the application for PD has not been widely established. This article aims to review the research progress of the application of RMST in PD rehabilitation to provide new sight into respiratory-related impairments management in people with PD.

Therapeutic Effect and Optimal Electrode Placement of Transcutaneous Neuromuscular Electrical Stimulation in Patients with Post-Stroke Dysphagia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: To date, there is no conclusive evidence that transcutaneous neuromuscular electrical stimulation (TNMES) benefits patients with post-stroke dysphagia (PSD). In addition, the optimal TNMES electrode placement has not been well-established. This systematic review and meta-analysis were conducted to investigate these two research gaps. Methods: Five major databases were systematically searched for randomized controlled trials (RCTs) through January 2022. Effect sizes were computed using Hedges’ g statistic, which were then entered into the random-effects model to obtain pooled effect estimates. Results: Twenty-four RCTs met the eligibility criteria. On the improvement of swallowing function, TNMES alone was not superior to conventional swallowing therapies (CSTs); combined therapy of TNMES and CSTs significantly surpassed CSTs alone (standardized mean difference (SMD) = 0.91, 95% confidence interval (95% CI): 0.68 to 1.14, p < 0.0001; I2 = 63%). Moreover, significant pooled effect sizes were observed in subgroups with horizontal electrode placement above the hyoid bone (SMD = 0.94, 95% CI: 0.72 to 1.16; I2 = 0%) and horizontal electrode placement just above and below the hyoid bone (SMD = 0.87, 95% CI: 0.59 to 1.14; I2 = 0%). The largest pooled effect size was observed in the subgroup that individualized electrode placement according to dysphagia evaluation (SMD = 1.65, 95% CI: 0.38 to 2.91; I2 = 90%). Conclusion: TNMES should be used in combination with CSTs for PSD. Horizontal electrode placement should target suprahyoid muscles or both suprahyoid and thyrohyoid muscles.

Acute effects of radiation treatment to submental muscles on burrowing and swallowing behaviors in a rat model

Swallowing impairments are a major complication of radiation treatment for oropharyngeal cancers, influencing oral intake and quality of life. The timing and functional consequences of radiation treatment on the swallowing process is not clearly understood. A rodent radiation injury model was used to investigate the onset of oral and pharyngeal dysfunctions in deglutition related to radiation treatment. This study tested the hypothesis that (Wall et al., 2013) alterations in normal biting, licking, and swallowing performance would be measurable following 64Gy of fractionated radiation to the submental muscles; and (Kotz et al., 2004) radiation will affect the animal’s general well-being as measured via burrowing activity. Seven rats received radiation using a clinical linear accelerator given in 8 fractions of 8Gy and another seven animals received sham anesthesia only treatment. Swallowing bolus transit/size was assessed via videofluoroscopy, tongue movement during drinking was measured via an electrical lick sensor, and biting was analyzed from acoustic recordings of a vermicelli pasta test. Burrowing activity was measured by the amount of gravel substrate displaced within a container. Measurements were taken at baseline, during treatment (1–4 weeks), and after completion of treatment (weeks 5 & 6). Decreases in licking frequency and increases in inter-lick interval were observed 5- and 6-weeks post-treatment. Significant decreases in burrowing performance, swallowing frequency, and inter-swallow interval were observed starting the last week of treatment and continuing up to 2-weeks after completion. Results suggest that tongue dysfunction is one of the first treatment related feeding problems to present immediately after the completion of radiation to the submental muscles.

Correlating muscle resection with functional swallow outcomes: An anatomic framework informed systematic review of the literature

OBJECTIVE

To perform a systematic review of studies reporting swallow-associated outcomes in patients who received surgery for head and neck cancer (HNC), informed by an anatomic and physiologic framework of pharyngeal phase of swallowing (Pearson's dual-sling model).

METHODS

PUBMED and Google Scholar databases were searched for peer-reviewed papers published between 1990 and 2019 using relevant MeSH terms. Exclusion criteria were 1) discussions comparing reconstruction techniques, 2) case-report/series (n < 10), 3) perspective articles, 4) papers comparing objective instrumental methods of swallowing evaluation, 5) animal/cadaver studies, 6) no instrumental or validated swallow assessment tools used, 7) papers that discuss/include radiotherapy treatment, 8) systematic reviews, 9) papers that discuss swallow training or rehabilitation methods. Two investigators reviewed papers meeting inclusion/exclusions criteria. Muscles resected, anatomic resection site, swallow outcomes, and patient treatment variables were collected.

RESULTS

A total of 115,020 peer-reviewed papers were identified. 74 papers were relevant to this review, 18 met inclusion and exclusion criteria, and none discussed surgical impact on the pharyngeal phase of swallowing using Pearson's dual-sling model. Most papers discussed the effect of tongue-base, supraglottic, or regional anatomic resection. Post-surgical resection Follow-up times ranged from 1 to 13 months. 67% of studies used objective instrumental swallow studies; 22% used patient reported outcome measures. Follow up time since surgical resection, time to feeding tube removal, feeding tube present/absent, aspiration severity were used to define dysphagia endpoints.

CONCLUSIONS

To date, no surgical HNC studies have used the dual-sling mechanism to guide study design, and dysphagia assessment has been inconsistent. To counsel patients on the effects of surgery on pharyngeal phase of swallow function, specialists need physiologically grounded research that correlates muscles resected with consistent measures of swallow function.

Decreased Maximal Tongue Protrusion Length May Predict the Presence of Dysphagia in Stroke Patients

Objective

To investigate the relationship between maximal tongue protrusion length (MTPL) and dysphagia in post-stroke patients.

Methods

Free tongue length (FTL) was measured using the quick tongue-tie assessment tool and MTPL was measured using a transparent plastic ruler in 47 post-stroke patients. The MTPL-to-FTL (RMF) ratio was calculated. Swallowing function in all patients was evaluated via videofluoroscopic swallowing study (VFSS), PenetrationAspiration Scale (PAS), Functional Oral Intake Scale (FOIS), and Videofluoroscopic Dysphagia Scale (VDS).

Results

The MTPL and RMF values were significantly higher in the non-aspirator group than in the aspirator group (MTPL, p=0.0049; RMF, p<0.001). MTPL and RMF showed significant correlations with PAS, FOIS and VDS scores. The cut-off value in RMF for the prediction of aspiration was 1.56, with a sensitivity of 84% and a specificity of 86%.

Conclusion

There is a relationship between MTPL and dysphagia in post-stroke patients. MTPL and RMF can be useful for detecting aspiration in post-stroke patients.

Increased cortical-medulla functional connectivity is correlated with swallowing in dysphagia patients with subacute infratentorial stroke

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Patients with infratentorial stroke showed increased cortex-medulla connectivity.

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The cortex-medulla functional connectivities were related to swallowing function.

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The identified regions may be candidates for non-invasive strategies for dysphagia.

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FC mapping using the medulla as a seed is useful in swallowing network research.

Patients with infratentorial stroke (IS) exhibit more severe dysphagia and a higher risk of aspiration than patients with supratentorial stroke. Nevertheless, a large proportion of patients with IS regain swallowing function within 6 months; however, the neural mechanism for this recovery remains unclear. We aimed to investigate possible neuroplastic changes involved using functional magnetic resonance imaging (fMRI) and their relation to swallowing function. We assessed 21 patients with IS (mean age: 59.9 ± 11.1 years) exhibiting dysphagia in the subacute phase and 21 healthy controls (mean age: 57.1 ± 7.8 years). Patient evaluations were based on the functional oral intake scale (FOIS), videofluoroscopic swallow study (VFSS), and fMRI. Temporal swallowing measures and the penetration-aspiration scale (PAS) were obtained using VFSS. Whole-brain–medulla resting-state functional connectivity (rsFC) was calculated and compared between patients and healthy controls. The rsFCs were also correlated with functional measures within the patient group. In patients with IS, whole-brain–medulla rsFCs were significantly higher in the precuneus, the left and right precentral gyrus, and the right supplementary motor area compared to those in healthy controls (P < 0.001, family-wise error-corrected cluster-level P < 0.05). The rsFCs to the medulla for the left (r = −0.507, P = 0.027) and right side (r = −0.503, P = 0.028) precentral gyrus were negatively correlated with the PAS. The rsFC between the left (r = 0.470, P = 0.042) and right (r = 0.459, P = 0.048) precentral gyrus to the medulla was positively correlated with upper esophageal sphincter opening durations (UOD). In addition, PAS was also correlated with UOD (r = −0.638, P = 0.003) whereas the laryngeal closure duration was correlated with the hyoid bone movement duration (r = 0.550, P = 0.015). Patients with IS exhibited overall modulation of cortical-medulla connectivity during the subacute phase. Patients with higher connectivities showed better swallowing performance. These findings support that there is cortical involvement in swallowing regulation after IS and can aid in determining potential treatment targets for dysphagia.

Effects of Presbyphagia on Oropharyngeal Swallowing Observed during Modified Barium Swallow Studies

OBJECTIVES

Understanding how aging impacts swallowing can help differentiate typical from atypical behaviors. This study aimed to quantify age-related swallowing alterations observed during a modified barium swallow study.

DESIGN

Cross-sectional study.

SETTING

Adult fluoroscopy suite in a metropolitan hospital at an academic center.

PARTICIPANTS

195 healthy adults distributed across 3 age categories: 21-39; 40-59; 60+ years.

MEASUREMENTS

17 physiologic components of swallowing across three functional domains (oral, pharyngeal, esophageal), including summed composite scores (Oral Total [OT] and Pharyngeal Total [PT]), from the validated and standardized Modified Barium Swallow Impairment Profile.

RESULTS

Most components (65%) demonstrated no impairment (scores of "0"). The odds of a worse (higher) score increased significantly with age for: Tongue Control during Bolus Hold, Hyolaryngeal Movement, Laryngeal Closure, Pharyngeal Contraction, and Pharyngoesophageal Segment Opening. OT and PT scores for 40-59-year-olds were worse than the youngest group (p=.01 and p <.001, respectively). Adults 60+ years had significantly worse PT scores among all groups (p-values <.01).

CONCLUSION

Oropharyngeal swallowing physiology evolves as healthy adults age and should be considered during clinical decision-making.

Electromyographic study assessing swallowing function in subacute stroke patients with respiratory muscle weakness

BACKGROUND

Dysphagia has been reported to be associated with the descent of the hyolaryngeal complex. Further, suprahyoid muscles play a greater role than infrahyoid muscles in elevation of the hyolarngeal complex. Respiratory muscle training (RMT) can improve lung function, and expiratory muscle strength training can facilitate elevation of the hyoid bone and increase the motor unit recruitment of submental muscles during normal swallowing. This study aimed to investigate the surface electromyography (sEMG) of the swallowing muscles, bilaterally, and the effect of RMT on swallowing muscles in stroke patients with respiratory muscle weakness.

METHODS

Forty patients with first episode of unilateral stroke were included in this retrospective controlled trial. After exclusion of 11 patients with respiratory muscle strength stronger than 70% of the predicted value, 15 were allocated to the RMT group and 14 to the control group. However, eventually, 11 patients in RMT group and 11 patients in control group completed the study. The sEMG of the orbicularis oris, masseter, submental, and infrahyoid muscles were recorded during dry swallowing, water swallowing (2 mL), and forced exhalation against a threshold breathing trainer set at different intensities, at baseline and after 6-week RMT.

RESULTS

Regarding the sEMG of submental muscles, there were significant between-group differences on the latency of the unaffected side (P = .048), significant change from baseline force on the unaffected side (P = .035), and significant between-side difference (P = .011) in the RMT group during dry swallowing. Significant change in the duration from baseline was observed on the affected side of the RMT group when blowing was set at 50% maximal expiratory pressure (MEP; P = .015), and on the unaffected side of the control group when blowing set at 15% MEP (P = .005). Significant difference was observed in the duration between 50% MEP and 15% MEP after 6-week program in the control group (P = .049).

CONCLUSIONS

A 6-week RMT can improve the electric signal of the affected swallowing muscles with more effect on the unaffected side than on the affected side during dry swallowing. Furthermore, RMT with 50% MEP rather than 15% MEP can facilitate greater submental muscle activity on the affected side in stroke patients with respiratory muscle weakness.

The effect of laryngeal elevation training on swallowing function in patients with dysphagia

OBJECTIVE

To investigate the effect of laryngeal elevation training without highly loaded head lifting on swallowing function in patients with dysphagia.

METHODS

Fifty-seven patients with dysphagia (36 men; mean age, 78.5 ± 11.4 years) were included. All participants performed the swallowing forehead exercise and the chin push-pull manoeuvre for two months. Videoendoscopy to assess swallowing function, the peak expiratory flow test and the hand grip strength test were performed at the initial visit (time 1) and two months after the start of the intervention (time 2). We used the Hyodo score, a scoring method for videoendoscopic assessment, for evaluation of swallowing function.

RESULTS

The linear mixed model showed a significant main effect of time (the Hyodo score at time 1 was greater than the score at time 2). The effects of the co-variates were not significant.

CONCLUSION

The present study demonstrated the significant effect of laryngeal elevation training without head lifting on the Hyodo score.

Chin tuck against resistance exercise for dysphagia rehabilitation: A systematic review

BACKGROUND

Chin tuck against resistance (CTAR) exercise has been recently reported to be a new therapeutic exercise method that can help improve swallowing function in patients with dysphagia. However, due to the differences in exercise protocols, methods and the tools used across studies of CTAR exercise, an overall systematic review of these studies is necessary.

OBJECTIVE

The present study investigated the exercise protocols, methods and tools used in various studies of CTAR exercise and summarised their findings.

METHODS

We searched for studies related to CTAR exercise using electronic databases and selected nine articles for review. The articles were categorised on the basis of four criteria: study design and quality, training protocol, outcome measures and clinical effect.

RESULTS

Four articles reported that CTAR exercise not only helped activate the suprahyoid muscle in healthy adults, but also activated the sternocleidomastoid muscle less than Shaker exercise. In addition, five articles reported that CTAR exercise was effective in improving swallowing function and oral diet stage in the pharyngeal phase, including reduction of airway aspiration in patients with dysphagia after stroke.

CONCLUSIONS

CTAR exercise more selectively activates the suprahyoid muscle and is an effective therapeutic exercise for improving swallowing function in patients with dysphagia. Because it is less strenuous than Shaker exercise, it requires less physical burden and effort, allowing greater compliance.

Effect of Volitional Effort on Submental Surface Electromyographic Activity During Healthy Swallowing

The effortful swallowing technique aims to compensate for or rehabilitate impaired swallowing by using maximal volitional effort to behaviorally modify aspects of swallowing physiology. Given that swallowing is a submaximal task, swallowing at submaximal levels has recently been suggested as a more task-specific therapeutic technique. The aim of this study was to investigate differences in muscle activity during minimum, regular, and maximum effort swallowing of different boluses and across different ages, with the goal of characterizing the task specificity of minimum effort and maximum effort swallowing. Forty-three healthy adults (22 female) representing four age groups (20-39, 40-59, 60-79, and 80 + years) participated in the study. They were verbally cued to swallow saliva and 5 mL water boluses using participant-determined minimum, regular, and maximum levels of effort, in randomized order. sEMG peak amplitude and duration of each swallow were measured. Linear mixed effects analyses demonstrated that compared to regular effort swallowing, maximum effort swallowing resulted in increased sEMG amplitude (p < .001) and prolonged duration (p < .001), while minimum effort swallowing resulted in decreased amplitude (p < .001) but no significant difference in duration (p = .06). These effects occurred regardless of age or bolus type. Differences in sEMG activity were smaller between regular and minimum effort swallowing than regular and maximum effort swallowing. Both increasing and decreasing volitional efforts during swallowing translate to significant modulation of muscle activity. However, regular swallowing is more similar to minimal effort swallowing. Results reinforce the concept of swallowing as a submaximal task, and provide insight into the development of sEMG biofeedback techniques for rehabilitation.

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

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

Examining the Relationships Between Lingual Strength, Perihyoid Strength, and Swallowing Kinematics in Dysphagic Adults: A Retrospective Cross-Sectional Analysis

Purpose The aim of this study was to examine the relationships of clinical measures of lingual and perihyoid strength with displacement swallowing kinematics and swallowing safety in a heterogenous group of dysphagic adults. Method A retrospective analysis was completed of videofluoroscopic swallow studies of consecutive dysphagic outpatient adults presenting to a tertiary swallowing center from January 1, 2015, to December 31, 2017. Videofluoroscopic swallow study records were included if containing displacement swallowing kinematics of a 20-ml single liquid swallow and clinical measures of anterior (L-MIPA) or posterior (L-MIPP) lingual maximal isometric press, saliva mean swallowing pressures (S-MSP), and/or open mouth-maximal isometric press (OM-MIP). Regression analyses were used to examine the relationships between clinical measures of lingual (L-MIPA, L-MIPP, S-MSP) and perihyoid (OM-MIP) strength and displacement swallowing kinematics, and binomial logistic regressions were used to examine the relationships between clinical measures of lingual and perihyoid strength and swallowing safety (Penetration-Aspiration Scale [PAS]). Results Multivariate regressions revealed significant relationships of L-MIPA, L-MIPP, S-MSP, and OM-MIP with group-level changes to the displacement swallowing kinematics. Univariate analyses revealed significant relationships of L-MIPA and L-MIPP with pharyngeal constriction ratio, maximal extent of upper esophageal segment opening, and PAS. Conclusions Weak relationships were identified of clinical measures of lingual and perihyoid strength with displacement swallowing kinematics. These findings suggest that clinical measures of lingual and perihyoid strength do not fully explain impairments in swallowing kinematics across a heterogenous group of dysphagic patients. Weak-to-moderate relationships were identified between clinical measures of lingual strength and PAS, suggesting that they may have value in predicting functional measures of swallowing safety. Further research is needed to examine how findings may differ between specific patient populations.

Effects of resistive jaw opening exercise in stroke patients with dysphagia: A double- blind, randomized controlled study

BACKGROUND

The resistive jaw opening exercise (RJOE) was suggested as a potential remedial treatment for patients with dysphagia. However, clinical evidence is insufficient.

OBJECTIVE

To investigate the effect of RJOE on hyoid bone movement, aspiration, and oral intake level in stroke patients with dysphagia.

METHODS

Forty stroke patients with dysphagia were randomly allocated into either the experimental group (n= 20) or placebo group (n= 20). The experimental group performed RJOE using a portable device, while the placebo group performed RJOE using a sham device with fewer loads. Intervention was conducted 5 times a week for 4 weeks. Hyoid bone movement was analyzed by two-dimensional analysis of anterior and superior motion based on a videofluoroscopic swallowing study. Aspiration was assessed using a penetration-aspiration scale (PAS), and oral intake level was assessed using the functional oral intake scale (FOIS).

RESULTS

Both groups showed statistically significant differences in hyoid movement, PAS, and FOIS scale (p< 0.05). However, after the intervention, there was no significant difference between the two groups except for the liquid type of PAS. Effect sizes (Cohen's d) were 0.9 and 0.7, 0.6 and 0.6, and 1.1 for the anterior and superior movement of the hyoid bone, semisolid and liquid type of PAS, and FOIS scale respectively.

CONCLUSIONS

This study suggests that RJOE helps in hyoid movement, aspiration reduction, and oral intake in patients with dysphagia after stroke.

Anatomy of inferior end of palatopharyngeus: its contribution to upper esophageal sphincter opening

PURPOSE

The palatopharyngeus is one of the longitudinal pharyngeal muscles which contributes to swallowing. It is reported that the palatopharyngeus has muscle bundles in various directions and with attachment sites, and each muscle bundle has a specific function. Although previous reports suggest that the palatopharyngeus is partly interlaced with some parts of the inferior constrictor, the precise relationship remains unclear. The purpose of this study was to examine the precise manner of the connection between the palatopharyngeus and inferior constrictor, and to examine the histological characteristics of this connection.

METHODS

We examined 15 halves of nine heads from Japanese cadavers (average age: 76.1 years); 12 halves, macroscopically, and three halves, histologically.

RESULTS

Our observation suggests that the palatopharyngeus spreads radially on the inner aspect of the pharyngeal wall. The most inferior portion of the palatopharyngeus extended to the inner surface of the cricopharyngeal part of the inferior constrictor. Histological analysis showed that the inferior end of the palatopharyngeus continued into the dense connective tissue located at the level of the cricoid cartilage. The dense connective tissue not only covered the inner surface of the inferior constrictor but also entered its muscle bundles and enveloped them.

CONCLUSION

Therefore, the palatopharyngeus interlaced the cricopharyngeal part of the inferior constrictor through the dense connective tissues. The findings of this study show that the palatopharyngeus may act on the upper esophageal sphincter directly and help in its opening with the aid of the pulling forces in the superolateral direction.

Effect of Dysphagia Rehabilitation Using Kinesiology Taping on Oropharyngeal Muscle Hypertrophy in Post-Stroke Patients: A Double Blind Randomized Placebo-Controlled Trial

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.

Comparison of 2 types of therapeutic exercise: jaw opening exercise and head lift exercise for dysphagic stroke: A pilot study

The aim of this study was to investigate the effect of the jaw opening exercise (JOE) on the thickness of the suprahyoid muscle and hyoid bone movement compared with the head lift exercise (HLE) in patients with dysphagia after strokeThis study recruited 30 patients with dysphagia after stroke. The JOE group performed a JOE using a resistance bar. The HLE group performed the traditional HLE. The total intervention duration was 6 weeks. We measured the thickness of the digastric and mylohyoid muscles using ultrasound. Two-dimensional motion analysis of the hyoid bone was performed using Image J software. The Borg rating of the perceived exertion scale was used to assess the intensity level of physical activity during the 2 exercises.Both groups showed a significant increase in the thickness of the digastric and mylohyoid muscles (P < .05). Hyoid bone motion was significantly increased in the anterior and superior movement in both groups (P < .05). After the intervention, there was no significant difference between the 2 groups. The Borg rating of perceived exertion scale for the JOE group was significantly lower than that of the HLE group (P < .05).In conclusion, this study demonstrated that the JOE and the HLE had similar effects with respect to increasing suprahyoid muscle thickness and improving hyoid bone movement. However, the JOE required less perceived exertion than the HLE.

Preterm Birth Impacts the Timing and Excursion of Oropharyngeal Structures during Infant Feeding

Swallowing in mammals requires the precise coordination of multiple oropharyngeal structures, including the palatopharyngeal arch. During a typical swallow, the activity of the palatopharyngeus muscle produces pharyngeal shortening to assist in producing pressure required to swallow and may initiate epiglottal flipping to protect the airway. Most research on the role of the palatopharyngeal arch in swallowing has used pharyngeal manometry, which measures the relative pressures in the oropharynx, but does not quantify the movements of the structures involved in swallowing. In this study, we assessed palatopharyngeal arch and soft palate function by comparing their movements in a healthy population to a pathophysiological population longitudinally through infancy (term versus preterm pigs). In doing so, we test the impact of birth status, postnatal maturation, and their interaction on swallowing. We tracked the three-dimensional (3D) movements of radiopaque beads implanted into relevant anatomical structures and recorded feeding via biplanar high-speed videofluoroscopy. We then calculated the total 3D excursion of the arch and soft palate, the orientation of arch movement, and the timing of maximal arch constriction during each swallow. Soft palate excursion was greater in term infants at both 7 and 17 days postnatal, whereas arch excursion was largely unaffected by birth status. Maximal arch constriction occurred much earlier in preterm pigs relative to term pigs, a result that was consistent across age. There was no effect of postnatal age on arch or soft palate excursion. Preterm and term infants differed in their orientation of arch movement, which most likely reflects both differences in anatomy and differences in feeding posture. Our results suggest that the timing and coordination of oropharyngeal movements may be more important to feeding performance than the movements of isolated structures, and that differences in the neural control of swallowing and its maturation in preterm and term infants may explain preterm swallowing deficits.

Best Practices in Modified Barium Swallow Studies

Purpose The modified barium swallow study (MBSS) is a widely used videofluoroscopic evaluation of the functional anatomy and physiology of swallowing that permits visualization of bolus flow throughout the upper aerodigestive tract in real time. The information gained from the examination is critical for identifying and distinguishing the type and severity of swallowing impairment, determining the safety of oral intake, testing the effect of evidence-based frontline interventions, and formulating oral intake recommendations and treatment planning. The goal of this review article is to provide the state of the science and best practices related to MBSS. Method State of the science and best practices for MBSS are reviewed from the perspectives of speech-language pathologists (SLPs) and radiologists who clinically practice and conduct research in this area. Current quandaries and emerging clinical and research trends are also considered. Results This document provides an overview of the MBSS and standards for conducting, interpreting, and reporting the exam; the SLPs' and radiologist's perspectives on standardization of the exam; radiation exposure; technical parameters for recording and reviewing the exam; the importance of an interdisciplinary approach with engaged radiologists and SLPs; and special considerations for examinations in children. Conclusions The MBSS is the primary swallowing examination that permits visualization of bolus flow and swallowing movement throughout the upper aerodigestive tract in real time. The clinical validity of the study has been established when conducted using reproducible and validated protocols and metrics applied according to best practices to provide accurate and reliable information necessary to direct treatment planning and limit radiation exposure. Standards and quandaries discussed in this review article, as well as references, provide a basis for understanding the current best practices for MBSS.

Respiratory muscle training in stroke patients with respiratory muscle weakness, dysphagia, and dysarthria - a prospective randomized trial

OBJECTIVE

To examine the efficacy of combined inspiratory and expiratory respiratory muscle training (RMT) with respect to the swallowing function, pulmonary function, functional performance, and dysarthria in patients with stroke.

DESIGN

Prospective, randomized controlled trial.

SETTING

Tertiary hospital.

PARTICIPANTS

The trial included 21 subjects (12 men, 9 women) aged 35 to 80 years presenting with 6 months history of unilateral stroke, respiratory muscle weakness (≥70% predicted maximal inspiratory pressure (MIP) and/or ≤70% maximal expiratory pressure (MEP)), dysphagia, or dysarthria. These subjects were randomly assigned to the control (n = 10, rehabilitation) and experimental (n = 11, rehabilitation with RMT) groups.

INTERVENTION

Inspiratory RMT starting from 30% to 60% of MIP and expiratory RMT starting from 15% to 75% of MEP for 5 days/week for 6 weeks.

MAIN OUTCOME MEASURES

MIP, MEP, pulmonary function, peak cough flow, perception of dyspnea, Fatigue Assessment Scale, Modified Rankin Scale, Brunnstrom stage, Barthel index, Functional Oral Intake Scale (FOIS), and parameters of voice analysis.

RESULTS

Significant differences were observed between both groups in terms of MIP, forced vital capacity (FVC), and forced expiratory volume per second (FEV1) of the percentage predicted. Significant difference was found with respect to the change in fatigue, shimmer percent, amplitude perturbation quotient, and voice turbulence index (VTI) according to the acoustic analysis in the RMT group. The FEV1/FVC ratio was negatively correlated with jitter percent, relative average perturbation, pitch perturbation quotient, and VTI; the maximum mid-expiratory flow (MMEF) and MMEF% were also negatively correlated with VTI. Significant differences among participants of the same group were observed while comparing the Brunnstrom stage before and after training of the affected limbs and the Barthel scale and FOIS scores in both the groups.

CONCLUSIONS

Altogether, 6-week combined inspiratory and expiratory RMT is feasible as adjuvant therapy for stroke patients to improve fatigue level, respiratory muscle strength, lung volume, respiratory flow, and dysarthria.Clinical trial registration number (Clinical Trial Identifier): NCT03491111.

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

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

Functional Anatomy Underlying Pharyngeal Swallowing Mechanics and Swallowing Performance Goals

Purpose

Rehabilitation of pharyngeal swallowing dysfunction requires a thorough understanding of the functional anatomy underlying the performance goals of pharyngeal swallowing. These goals include the safe and efficient transfer of a bolus through the hypopharynx into the esophagus. Penetration or aspiration of a bolus threatens swallowing safety. Bolus residue indicates swallowing inefficiency. Several primary mechanics, or elements of the swallowing mechanism, underlie these performance goals, with some elements contributing to both goals. These primary mechanics include velopharyngeal port closure, hyoid movement, laryngeal elevation, pharyngeal shortening, tongue base retraction, and pharyngeal constriction. Each element of the swallowing mechanism is under neuromuscular control and is therefore, in principle, a potential target for rehabilitation. Secondary mechanics of pharyngeal swallowing, those movements dependent on primary mechanics, include opening the upper esophageal sphincter and epiglottic inversion.

Conclusion

Understanding the functional anatomy of pharyngeal swallowing underlying swallowing performance goals will facilitate anatomically informed critical thinking in the rehabilitation of pharyngeal swallowing dysfunction.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Functional Modules of Pharyngeal Swallowing Mechanics

OBJECTIVES

The present retrospective cohort study aims to test the hypothesis that elements of swallowing mechanics including hyoid movement, laryngeal elevation, tongue base retraction, pharyngeal shortening, pharyngeal constriction, and head and neck extension can be grouped into functional modules, and that these modules are predictably altered in disease states.

METHODS

Modified barium swallow video clips of a thick and a thin liquid swallow from 40 normal patients and 10 dysphagic post-treatment oropharyngeal head-and-neck cancer (HNC) patients were used in this study. Coordinate locations of 12 anatomical landmarks mapping pharyngeal swallowing mechanics were tracked on every frame during the pharyngeal phase of each swallow using a custom-made MATLAB tool. Morphometric modularity hypothesis testing was performed on these coordinate data to characterize the modular elements of swallowing function in each cohort using MorphoJ software.

RESULTS

The elements of normal swallowing can be grouped into four functional modules including bolus propulsion, pharyngeal shortening, airway protection, and head and neck posture. Modularity in HNC patient showed an intact airway protection module but altered bolus propulsion and pharyngeal shortening modules. To cross-validate the alteration in modules, a post hoc analysis was performed, which showed significantly increased vallecular (P < .04) and piriform (P < .05) residue but no significant change in aspiration status in the HNC cohort versus controls.

CONCLUSIONS

This study suggests that while pharyngeal swallowing mechanics is highly complex, the system is organized into functional modules, and that changes in modularity impacts swallowing performance. This approach to understanding swallowing function may help the patient care team better address swallowing difficulties.

LEVEL OF EVIDENCE

2b.

The Recline and Head Lift Exercises: A Randomized Clinical Trial Comparing Biomechanical Swallowing Outcomes and Perceived Effort in Healthy Older Adults

Purpose The aim of this study was to compare biomechanical swallowing outcomes and perceived effort as well as detraining effects of the established Head Lift Exercise (HLE) and the novel Recline Exercise (RE) in healthy older adults. Method Twenty-two healthy older adults were randomized to perform either the RE or the HLE for a period of 6 weeks. Subjects underwent videofluoroscopic swallowing studies at 3 time points (baseline, postexercise, and following a 6-week detraining period). Primary outcome measures included biomechanical measures of superior and anterior hyoid excursion and upper esophageal sphincter opening, obtained using kinematic analyses on the recorded swallows. Perceived exertion ratings during exercise, as measured by the Borg scale, were included as a secondary outcome measure. Linear mixed-effects models were utilized to compare exercise groups and evaluation time points. Results The 2 exercise groups did not differ significantly in age, body mass index, or body fat percentage at baseline. Significant postexercise increases were seen in superior hyoid excursion, F(2, 36.7) = 24.01, p ≤ .0001, and anterior hyoid excursion, F(2, 36.7) = 5.40, p = .0088, for both exercise groups. Upper esophageal sphincter opening did not increase significantly following the exercise regimens, F(2, 36.5) = 2.14, p = .1322. Both groups displayed a significant decrease in perceived exertion levels over the course of the exercises, F(5, 98) = 23.73, p ≤ .0001. On average, Borg ratings were 20% lower for the RE group than the HLE group at all time points, F(5, 20) = 7.94, p = .0106, indicating that this exercise was perceived as easier to perform. Eighteen participants were followed after detraining, and no differences in detraining effects were seen between groups. In general, gains in biomechanical measures were better maintained on larger bolus types. Conclusions In healthy older adults, the HLE and the RE produced similar gains and detraining effects in biomechanical swallow outcomes. The RE exercise, however, required significantly less effort. These findings suggest that the RE is easier to perform for healthy older adults and thus may be a valuable treatment option for individuals who have difficulty performing the HLE. Further investigation in patients with dysphagia is warranted. Supplemental Material https://doi.org/10.23641/asha.7742897.

Open Mouth-Maximal Isometric Press: Development and Norms for Clinical Swallowing Evaluations and Treatment

Purpose The aims of this study were to (a) describe the development and utility of the Open Mouth-Maximal Isometric Press (OM-MIP), a tool designed for the quantitative assessment of suprahyoid-infrahyoid muscle strength; (b) examine the effects of age and sex on the OM-MIP; and (c) establish age- and sex-based OM-MIP norms. Method Two hundred sixteen healthy male and female volunteers were recruited. Participants performed the OM-MIP, and the maximum of 3 trials that were within 10% of each other was recorded. Rest between each trial was allowed to avoid fatigue. Multiple regression examined the influence of age and sex on the OM-MIP. Descriptive statistics outlined normative OM-MIP values for young adult (aged 18-39 years), middle-aged adult (aged 40-59 years), old adult (aged 60-79 years), and very old adult (aged ≥ 80 years) men and women. Two-way analysis of variance determined if normative data differed significantly between the age and sex groups. Results Age and sex significantly influenced the OM-MIP, although no significant interaction effect was identified. Women had lower mean OM-MIPs when compared with men ( p < .0005), and very old adults had lower mean OM-MIPs when compared with young ( p = .001), middle-aged ( p < .0005), and old ( p = .013) adults. Conclusions This study establishes age- and sex-based OM-MIP norms and outlines its potential utility during clinical swallowing evaluations and treatment. By providing these norms, clinicians can begin to quantitatively measure suprahyoid and infrahyoid strength, individualize resistance training programs to patients' OM-MIP 1 repetition maximum, and track strength changes over time in response to therapeutic interventions.

Swallowing function in advanced tongue cancer patients before and after bilateral neck dissection following superselective intra-arterial chemoradiotherapy for organ preservation: a case-control study

OBJECTIVE

This study aimed to evaluate swallowing function in advanced tongue cancer patients before and after bilateral neck dissection following superselective intra-arterial chemoradiotherapy (CRT).

METHODS

A videofluoroscopic swallowing study (VFSS) was used to evaluate swallowing function in 10 patients with advanced tongue cancer before and after bilateral neck dissection.

RESULTS

Laryngeal penetration increased in the postoperative VFSS. Temporal analysis comparing two time points revealed that, after surgery, oral transit time increased significantly, but there was no difference in pharyngeal delay time or pharyngeal transit time. Spatial analysis revealed significant decreases after surgery in the maximum distance of upper esophageal sphincter (UES) opening, the maximum distance of hyoid bone movement in both the anterior and superior direction, and the maximum velocity of hyoid bone movement.

CONCLUSIONS

Laryngeal penetration and aspiration increased as a result of limited hyoid movement and diminished UES opening after bilateral neck dissection following superselective intra-arterial CRT for advanced tongue cancer.

Functional Swallowing Units (FSUs) as organs-at-risk for radiotherapy. PART 1: Physiology and anatomy

BACKGROUND AND PURPOSE

When optimising radiotherapy treatments today, the pharyngeal constrictor muscles and the larynx are usually regarded as the swallowing organs at risk (SWOARs). The purpose of this study was to identify and describe additional, previously undefined groups of muscles (functional units) involved in crucial components of swallowing (hyolaryngeal elevation (HLE), tongue base retraction (TBR) and tongue motion), and to emphasise their relevance in radiation-induced dysphagia.

MATERIAL AND METHODS

Based on available literature on human anatomy and swallowing physiology, the functional units of muscles involved in HLE, TBR and tongue motion have been identified and described.

RESULTS AND CONCLUSION

Functional swallowing units (FSUs) were defined as groups of swallowing muscles sharing their function, that are in close proximity to each other. Seven FSUs involved in HLE, TBR and tongue motion were identified: floor of mouth, thyrohyoid muscles, posterior digastric/stylohyoid muscles complex, longitudinal pharyngeal muscles, hyoglossus/styloglossus muscles complex, genioglossus muscles, intrinsic tongue muscles. The swallowing physiology and anatomy of the FSUs described in this paper will lead to a greater understanding of radiation-induced dysphagia mechanisms and, consequently, to an improvement in the development of swallowing sparing strategies. This article (PART 1) serves as the theoretical foundation for a subsequent article (PART 2), which provides detailed delineation guidelines for FSUs.

Effects of Resistive Jaw-Opening Exercise with Elastic Bands on Suprahyoid Muscle Activation in Normal Subjects

OBJECTIVE

The effect of a resistive jaw-opening exercise using an elastic band on suprahyoid muscle activity and tongue strength was examined in healthy volunteers.

METHODS

Twenty-one adults wore an elastic loop around their head and mandible. To prescribe the appropriate elastic band resistance, the 10-repetition maximum (10 RM) was measured among 4 bands at baseline. Band loops, starting with the highest resistance value band, were sequentially applied to determine the suitability for 10 RM. During the exercise, the participants were required to open their jaw maximally and maintain the position for 10 s; then, they rested for 10 s. This procedure was repeated for 20 min, 3 days per week for 8 weeks to test suprahyoid muscle activation during effortful swallowing; isometric tongue pressures of the tongue tip and base at baseline, after 4, and after 8 weeks of training were measured.

RESULTS

Peak suprahyoid muscle activation amplitudes during effortful swallow and isometric pressures at the tongue tip significantly increased after 8 weeks.

CONCLUSION

The 8-week resistive jaw-opening exercise significantly improved strength of the suprahyoid muscle and tongue pressures in healthy subjects. These positive results warrant further investigation of the therapeutic effects and feasibility of this resistive exercise.