Changes of timing variables in swallowing of boluses with different viscosities in patients with dysphagia

Location of the upper oesophageal sphincter during swallowing: Analysis using swallowing CT

BACKGROUND

Upper oesophageal sphincter (UES) serves as an important anatomical and functional landmark during swallowing. However, the precise UES location before and during swallowing has not been well established.

OBJECTIVE

This study aimed to determine upper oesophageal sphincter (UES) location and displacement during swallowing accounting for sex, age, and height in healthy adults using 320-row area detector computed tomography (320-ADCT).

METHODS

Ninety-four healthy adults (43 males; 22-90 years) underwent 320-ADCT scanning while swallowing one trial of 10 mL honey thick barium. UES location at bolus hold and at maximum displacement and vertical displacement during swallowing were identified using the coordinates and the section classification of vertebrae (VERT scale). The differences and correlations of UES location and distance in terms of sex, age, and height were analysed using Mann-Whitney U test and Spearman's correlation coefficient.

RESULTS

UES locations at bolus hold and at maximum displacement were significantly lower and UES vertical displacement was significantly larger in males than in females (p < .001). UES location at bolus hold became lower with increasing age (r = -.312, p = .002), but the negative correlation was low at maximum displacement (r = -.230, p = .026), resulting in larger vertical distance with ageing. UES locations showed high negative correlation at bolus hold with height (r = -.715, p < .001), and showed moderate negative correlation at maximum displacement with height (r = -.555, p < .001), although this effect was unclear when analysed by sex.

CONCLUSION

Males showed lower UES location and larger displacement than females. The impact of age was evident with lower location before swallowing and larger displacement during swallowing. Differences observed by sex were not completely explained by using the VERT scale to adjust for height.

Normal Variations in Upper Esophageal Sphincter Function During Deglutition: A Secondary Analysis of Videofluoroscopic Data

OBJECTIVE

Cricopharyngeal dysfunction is a common potential cause of pharyngoesophageal dysphagia. Contextual factors (i.e., personal demographics and bolus properties) appear to impact upper esophageal sphincter (UES) function but have yet to be assessed collectively in a large-scale study using psychometrically sound swallow task procedures. Using a standardized and validated videofluoroscopic approach, we investigated the collective effects of age, sex, and swallow task on UES opening duration (UESOdur) and UES maximum distension (UESmax) in a large sample of healthy adults.

METHODS

UESOdur and UESmax data were analyzed from existing videofluoroscopic images of 195 healthy adults (21-89 years old) across seven swallow tasks (thin liquid to viscous liquids, puree, and a solid). Generalized estimating equation modeling captured the effects of the aforementioned contextual factors (α = 0.05).

RESULTS

UESOdur significantly increased with age, while UESmax had an inverse relationship. Females had significantly wider UESmax. UESOdur of 5 mL thin liquid was significantly shorter than all other liquid swallow tasks, while solid had an inverse effect. Compared to 5 mL thin liquid, all other swallow tasks resulted in significantly wider UESmax. Mildly and moderately thick liquid significantly increased UESOdur when isolating viscosity. UESmax was significantly wider with mildly and moderately thick liquid and puree than thin liquid. When isolating volume, cup sip thin liquid increased both measures significantly relative to 5 mL.

CONCLUSION

Age, sex, and swallow task can influence the normal timing and extent of UES movement. These collective effects contribute to normal variability in UES function and should be considered for clinical decision-making.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2306-2315, 2024.

Effectiveness of an evidence-based swallowing facilitation strategy for patients undergoing radiotherapy for head and neck cancer: a study protocol for a randomised controlled trial

INTRODUCTION

Dysphagia emerges as a frequent, persistent and enduring aftermath in individuals undergoing radiotherapy for head and neck cancer (HNC). Timely intervention becomes imperative to ameliorate prolonged dysphagia and curtail related complications. Among the evidence-grounded tactics, preventive swallowing training and proficient feeding management stand out as pivotal measures for precluding and mitigating dysphagia. However, past inquiries that amalgamated these dual interventions exhibited heterogeneous quality due to their restricted participant cohorts and a dearth of uniform, systematic and practicable procedural benchmarks.

METHOD/DESIGN

This randomised, parallel-controlled study enrols 94 patients diagnosed with HNC, who are undergoing radiotherapy either with or without concurrent chemotherapy. The patients will be randomly assigned to either the intervention group, which will receive a facilitation strategy to enhance swallowing function in conjunction with standard care, or the control group, which will receive typical radiotherapy care. Patient assessments will be conducted at three distinct time points: at the onset of radiotherapy (baseline), at the conclusion of radiotherapy and 3 months postradiotherapy. The primary outcome will revolve around measuring swallowing function, while secondary outcomes will encompass swallowing-related quality of life and nutritional status.

ETHICS AND DISSEMINATION

This research initiative received endorsement from the Shanghai Proton Heavy Ion Hospital Ethics Committee on 2 December 2 (Approval Number 2210-59-01). Throughout the recruitment process, patients will be acquainted with the primary aims and scope of the study. Their participation will be a voluntary choice, demonstrated by their informed consent form signatures. The outcomes of this study will be disseminated through publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov, ChiCTR2300067550, registered 11 January 2023.

Quantifying Oropharyngeal Swallowing Impairment in Response to Bolus Viscosity

PURPOSE

The purpose of this study was to test the feasibility for quantifying changes in oropharyngeal swallowing impairment in response to alteration in bolus viscosity using a reliable and valid method of observational measurement-the Modified Barium Swallow Impairment Profile (MBSImP).

METHOD

This retrospective analysis included a heterogeneous cohort of 119 patients with suspected dysphagia that underwent a videofluoroscopic swallowing study as part of clinical care. Using consensus scoring, two expert clinicians assigned MBSImP scores to components related to oropharyngeal swallowing function between two bolus viscosities (thin liquid and pudding): epiglottic movement, laryngeal elevation, anterior hyoid excursion, tongue base retraction, pharyngeal stripping wave, and pharyngoesophageal segment opening (PESO). Comparisons between the two bolus viscosities were investigated for each component.

RESULTS

Higher (worse) scores were observed in the thin-liquid trial compared with the pudding trial for the following MBSImP components: anterior hyoid excursion (p = .03), epiglottic movement (p < .001), pharyngeal stripping wave (p < .001), and PESO (p = .002). Lower (better) scores were observed in the liquid trial compared with the pudding trial for one component-tongue base retraction (Component 15) only (p < .001).

CONCLUSION

These findings provide further evidence for positive influences of viscosity on the swallow mechanism, including influences of sensory feedback on the sensorimotor swallow program.

Effects of Head and Neck Alignment and Pharyngeal Anatomy on Epiglottic Inversion During Swallowing in Dysphagic Patients

The effects of head and neck alignment and pharyngeal anatomy on epiglottic inversion remain unclear. This study investigated the factors involved in epiglottic inversion, including head and neck alignment and pharyngeal anatomy, in patients with dysphagia. Patients with a chief complaint of dysphagia and who underwent videofluoroscopic swallowing study at our hospital from January to July 2022 were enrolled. They were divided into three groups based on the degree of epiglottic inversion as the complete-inversion (CI), partial-inversion (PI), and non-inversion group (NI) groups. Data were compared among the three groups; a total of 113 patients were analyzed. The median age was 72.0 (IQR: 62.0-76.0) years; 41 (36.3%) and 72 (63.7%) were women and men, respectively. There were in 45 (39.8%) patients in the CI, 39 (34.5%) in the PI, and 29 (25.7%) in the NI groups, respectively. Single-variable analysis revealed significant relation to epiglottic inversion of Food Intake LEVEL Scale score, penetration-aspiration score with 3-mL thin liquid bolus, epiglottic vallecula and pyriform sinus residue, hyoid position and displacement during swallowing, pharyngeal inlet angle (PIA), epiglottis to posterior pharyngeal wall distance, and body mass index. Logistic regression analysis with complete epiglottic inversion as the dependent variable revealed the X coordinate at maximum hyoid elevation position during swallowing and PIA as significant explanatory variables. These results suggest that epiglottic inversion is constrained in patients with dysphagia who have poor head and neck alignment or posture and a narrow pharyngeal cavity just before swallowing.

Kinematic mechanism of the rehabilitative effect of 4-channel NMES: post-hoc analysis of a prospective randomized controlled study

The sequential 4-channel neuromuscular electrical stimulation (NMES), based on the normal contractile sequences of swallowing-related muscles, is a new rehabilitative treatment. The objective of this study was to explore the mechanism of the rehabilitative effect of the 4-channel NMES using kinematic analysis of videofluoroscopic swallowing study (VFSS) data. For this post-hoc analysis, we included a subset of participants from the prospective randomized controlled study on the clinical effectiveness of the sequential 4-channel NMES compared with that of the conventional 2-channel NMES. Seventeen subjects (11 and six in the 4- and 2-channel NMES groups, respectively) were eligible for the kinematic analysis of VFSS data. The hyoid bone movement was analyzed by evaluating the distance and time parameters with four peak points (A, B, C, D). The 4-channel NMES group showed significant improvement in vertical distances (A-C), horizontal distance (A-B, A-C), time interval (A-B-C) and total time, compared with their pretreatment data. The 2-channel NMES group showed significant improvements in time interval (A-B); however, the Euclidean distance (A-D) and mean velocity of the Euclidean distance (A-C) were significantly decreased. When the two groups were directly compared, the 4-channel group showed significantly greater improvement in horizontal distance (A-B), Euclidean distance (A-D), time interval (A-B-C), and mean velocity the Euclidean distance (A-D). The results in this study suggest that the sequential 4-channel NMES might lead to the physiologic circular movement of the hyoid bone during swallowing, and therefore be an effective treatment for dysphagia.Trial registration: Clinicaltrials.gov, registration number: NCT03670498.

Rheological Issues on Oropharyngeal Dysphagia

There is an increasing proof of the relevance of rheology on the design of fluids for the diagnosis and management of dysphagia. In this sense, different authors have reported clinical evidence that support the conclusion that an increase in bolus viscosity reduces the risks of airway penetration during swallowing. However, this clinical evidence has not been associated yet to the definition of objective viscosity levels that may help to predict a safe swallowing process. In addition, more recent reports highlight the potential contribution of bolus extensional viscosity, as elongational flows also develops during the swallowing process. Based on this background, the aim of this review paper is to introduce the lecturer (experts in Dysphagia) into the relevance of Rheology for the diagnosis and management of oropharyngeal dysphagia (OD). In this sense, this paper starts with the definition of some basic concepts on Rheology, complemented by a more extended vision on the concepts of shear viscosity and elongational viscosity. This is followed by a short overview of shear and elongational rheometrical techniques relevant for the characterization of dysphagia-oriented fluids, and, finally, an in-depth analysis of the current knowledge concerning the role of shear and elongational viscosities in the diagnosis and management of OD (shear and elongational behaviors of different categories of dysphagia-oriented products and contrast fluids for dysphagia assessment, as well as the relevance of saliva influence on bolus rheological behavior during the swallowing process).

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

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

Comparison of methods for evaluation of upper esophageal sphincter (UES) relaxation duration: Videofluoroscopic swallow study versus high-resolution manometry

This study aims to compare the 2 methods of upper esophageal sphincter (UES) relaxation measurement and determine which method has better diagnostic value in UES relaxation impairment The study included 140 patients with pharyngeal dysphagia who underwent both videofluoroscopic swallow study (VFSS) and high-resolution manometry (HRM). Feeding method was determined to oral or non-oral feeding based on the severity of dysphagia; 103 patients were in oral feeding group and 37 were in non-oral feeding group. UES relaxation duration was measured using VFSS and HRM, respectively. Receiver-operating characteristic curve analysis was conducted to validate the UES relaxation duration in determination of feeding method. UES relaxation duration was more decreased in non-oral feeding group than in oral feeding group on both VFSS and HRM. Receiver-operating characteristic analysis revealed that the optimal cutoff value of UES relaxation duration to determine feeding method (oral or non-oral feeding) was 0.42 seconds on VFSS and 0.44 seconds on HRM. The sensitivity for feeding method was higher in VFSS than HRM (83.5% vs 70.9%), while the specificity was higher in HRM than VFSS (48.6% vs 54.1%). VFSS and HRM have complementary ability in evaluating UES relaxation duration in patients with oropharyngeal dysphagia.

Temporal measures of oropharyngeal swallowing events identified using ultrasound imaging in healthy young adults

Swallowing is a complex process that involves precise coordination among oral and pharyngeal structures, which is essential to smooth transition of bolus and adequate airway protection. Tongue base retraction and hyolaryngeal excursion are two significant swallowing movements, and their related events can be examined using ultrasound imaging, which is physically and radioactively non-invasive. The present study aimed to 1) establish the temporal sequences and timing of swallowing events identified using ultrasound imaging, and 2) investigate the variability of the above temporal sequences and 3) investigate the effect of bolus type on the variability of temporal sequences in non-dysphagic individuals. Forty-one non-dysphagic young adults of both genders (19 males and 22 females) participated in the study. Ultrasound images were acquired mid-saggitally at their submental region during swallowing of boluses with different volume (i.e. 5mL or 10mL) and consistencies (i.e. IDDSI Levels 0 and 4). Timing and sequence of six events 1) displacement onset (TBOn), 2) maximum displacement (TBMax) and 3) displacement offset of tongue base retraction (TBOff); and, 4) displacement onset (HBOn), 5) maximum displacement (HBMax) and 6) displacement offset of the hyoid bone excursion (HBOff) were extracted from the ultrasound images. Out of the 161 swallows, 85.7% follow a general sequence of HBOn < TBOn < HBMax < TBMax < HBOff < TBOff. Percentage adherence to six anticipated paired-event sequences was studied. Results suggested the presence of individual variability as adherence ranged from 75.8% to 98.1% in four of the anticipated sequences, leaving only two sequences (HBOn < TBMax and TBMax < HBOff) obligatory (i.e. 100% adherence). For non-obligatory sequences, it was found that bolus type may have an effect on the level of adherence. Findings of the present study lay the groundwork for future studies on swallowing using ultrasound imaging and also the clinical application of ultrasonography.

Pharyngo-Esophageal Modulatory Swallow Responses to Bolus Volume and Viscosity Across Time

Objectives/Hypothesis

Modulation of the pharyngeal swallow to bolus volume and viscosity is important for safe swallowing and is commonly studied using high‐resolution pharyngeal manometry (HRPM). Use of unidirectional pressure sensor technology may, however, introduce variability in swallow measures and a fixed bolus administration protocol may induce time and order effects. We aimed to overcome these limitations and to investigate the effect of time by repeating randomized measurements using circumferential pressure sensor technology.

Study Design

Sub‐set analysis of data from the placebo arm of a randomized, repeated measures trial.

Methods

HRPM with impedance was recorded using a solid‐state catheter with 36 circumferential pressure sensors and 18 impedance segments straddling from hypopharynx to stomach. Testing included triplicates of 5, 10, and 20 ml thin liquid and 10 ml thick liquid boluses, the order of the thin liquid boluses was randomized. The swallow challenges were repeated approximately 10 minutes after finishing the baseline measurement.

Results

We included 19 healthy adults (10/9 male/female; age 24.5 ± 4.1 year). Intrabolus pressure, all upper esophageal sphincter (UES) opening and relaxation metrics, and flow timing metrics increased with larger volumes. A thicker viscosity decreased UES relaxation time, UES basal pressure, and flow timing metrics, whereas UES opening extent increased. Pre‐swallow UES basal pressure and post‐swallow UES contractile integral decreased over time.

Conclusion

Using circumferential pressure sensor technology, the effects of volume and viscosity were largely consistent with previous reports. UES contractile pressures reduced over time. The growing body of literature offers a benchmark for recognizing aberrant pharyngo‐esophageal motor responses.

Level of Evidence

3 Laryngoscope, 132:1817–1824, 2022

Electromyographic activation patterns during swallowing in older adults

Age-related weakness due to atrophy and fatty infiltration in oropharyngeal muscles may be related to dysphagia in older adults. However, little is known about changes in the oropharyngeal muscle activation pattern in older adults. This was a prospective and experimental study. Forty healthy participants (20 older [> 60 years] and 20 young [< 60 years] adults) were enrolled. Six channel surface electrodes were placed over the bilateral suprahyoid (SH), bilateral retrohyoid (RH), thyrohyoid (TH), and sternothyroid (StH) muscles. Electromyography signals were then recorded twice for each patient during swallowing of 2 cc of water, 5 cc of water, and 5 cc of a highly viscous fluid. Latency, duration, and peak amplitude were measured. The activation patterns were the same, in the order of SH, TH, and StH, in both groups. The muscle activation patterns were classified as type I and II; the type I pattern was characterized by a monophasic shape, and the type II comprised a pre-reflex phase and a main phase. The oropharyngeal muscles and SH muscles were found to develop a pre-reflex phase specifically with increasing volume and viscosity of the swallowed fluid. Type I showed a different response to the highly viscous fluid in the older group compared to that in the younger group. However, type II showed concordant changes in the groups. Therefore, healthy older people were found to compensate for swallowing with a pre-reflex phase of muscle activation in response to increased liquid volume and viscosity, to adjust for age-related muscle weakness.

Impact of Thickened Liquids on Laryngeal Movement Velocity in Patients with Dysphagia

Considering that thickened liquids are frequently used for patients with dysphagia, elucidating their impact on laryngeal dynamics is important. Although studies have investigated the impact of thickened liquids on laryngeal movement velocity among healthy young adults, no study has examined the same among patients with dysphagia. We aimed to elucidate the influence of bolus consistency on laryngeal movement velocity and surface electromyographic activity of the suprahyoid muscles in patients with dysphagia. Participants included 18 male, poststroke patients with dysphagia, whereas patients with true bulbar paralysis, head and neck cancer, neuromuscular disease, or recurrent nerve paralysis were excluded. A video fluoroscopic swallowing study (VFSS) was performed while swallowing 3 mL of moderately thick and thin liquids. Quantitative VFSS analysis, including factors such as laryngeal peak velocity, laryngeal mean velocity, laryngeal movement distance, duration of the laryngeal elevation movement, and the temporal location of laryngeal vestibule closure within the laryngeal elevation movement was performed. Muscle activity was evaluated using integrated muscles activity values obtained from electromyography (iEMG) of the suprahyoid muscle during swallowing. VFSS analysis showed that laryngeal peak velocity and laryngeal mean velocity were significantly faster while swallowing moderately thick than while swallowing thin liquids. Laryngeal movement distance was significantly greater while swallowing moderately thick than while swallowing thin liquids. iEMG was significantly higher while swallowing moderately thick liquids than while swallowing thin liquids. Compared to thin liquids, moderately thick induced an increase in laryngeal movement velocity and in suprahyoid muscle activity among patients with dysphagia, a finding consistent with that of a previous study among healthy adults.

Effects of Chin-Down Maneuver on Pharyngeal Pressure Generation According to Dysphagia and Viscosity

Objective

To demonstrate the effects of chin-down maneuver on swallowing by using high-resolution manometry (HRM).

Methods

HRM data of 20 healthy subjects and 64 dysphagic patients were analyzed. Participants swallowed 5 mL of thin and honey-like liquids in neutral and chin-down positions. HRM was used to evaluate maximal velopharyngeal pressure/area, maximal tongue base pressure/area, maximal pharyngeal constrictor pressure, pre-/post-swallow upper esophageal sphincter (UES) peak pressure, minimal UES pressure, UES activity time, and nadir duration.

Results

Compared to the neutral position, the chin-down maneuver significantly increased tongue base pressure in both normal and dysphagic groups as well as for both honey-like and thin viscosities, although the honey-like liquid did not reach statistical significance in the dysphagic group. Regarding pharyngeal constrictors and pre-swallow peak UES pressure, the healthy group showed a significant decrease in thin liquid swallowing and decreasing tendency in honeylike liquid swallowing. UES nadir duration was significantly decreased for honey-like liquid swallowing in the dysphagic group and for both thin and honey-like liquids in the healthy group. UES nadir duration of honey-like and thin flow swallowing in the dysphagia group was 0.26 seconds after the chin-down maneuver, which was severely limited.

Conclusion

This study showed a different kinetic effect of the chin-down maneuver between the healthy and dysphagic groups, as well as between thin and honey-like viscosities. The chin-down maneuver increased tongue base pressure and decreased UES nadir duration, which the latter was severely limited in dysphagic patients. Therefore, appropriate application of the chin-down maneuver in clinical practice is required.

Oropharyngeal Swallowing Dynamic Findings in People with Asthma

Airflow obstruction in people with asthma, similar to COPD, may interfere with swallowing, increasing the risk of food or liquid entrance into the lower airways, and favoring the uncontrolled disease. To describe the complaints and findings of the oropharyngeal swallowing mechanisms in patients with mild and severe asthma, a cross-sectional study was performed. A total of 135 participants with asthma were studied, of whom 97 had severe asthma and 38 had mild asthma. All subjects answered a questionnaire with demographic information, disease exacerbations, Asthma Control Questionnaire 6 (ACQ6-Juniper 1999), GastroEsophageal Reflux Disease Symptoms Questionnaire (GERD-SQ-Fornari et al. 2004), and Eating Assessment Tool 10 (EAT-10-Gonçalves et al., 2013). The oral and pharyngeal swallowing assessment occurred via videofluoroscopic swallowing evaluation. The age range of the participants was from 19 to 80 years, with a predominance of females (78.6%). Uncontrolled asthma was observed in 50 (52%) of the patients with severe asthma and in 11 (29%) of the patients with mild asthma (ACQ6 > 1.5). The GERD-SQ and EAT-10 scores were similar in both groups. In the bivariate analysis, the group with severe asthma presented with more changes when compared to the group with mild asthma in the following events: atypical lingual movement during the swallowing of liquid in the volumes of 5 ml (p = 0.003) and 10 ml (p = 0.001), and solid (p = 0.009); oral transit time increased in swallowing of liquid in the volumes of 5 ml (p = 0.003) and 20 ml (p = 0.026); beginning of the pharyngeal swallowing phase below the mandibular ramus (p = 0.003); pharyngeal residue (p = 0.017) of solid consistency; laryngeal penetration of 5 ml (p = 0.050) and 20 ml (p = 0.032) of liquid; increased transition time between the oral and pharyngeal swallowing phases (p = 0.035) and increased pharyngeal transit time (p = 0.045) of solid consistency. Tracheal aspiration was observed only in the group with severe asthma. After the multivariate analysis, atypical tongue movement maintained a statistically significant difference between the two groups. Oropharyngeal swallowing alternations were frequent in the studied sample and more markedly present in patients with severe asthma. Multivariate regression revealed atypical lingual movement, which was greater in patients with severe asthma. The clinical significance of these findings should be further investigated.

Increased episodes of aspiration on videofluoroscopic swallow study in children with nasogastric tube placement

Background

Given the limited evidence available, the impact of nasogastric (NG) tube placement on swallowing in children is not well understood. When a child needs to be fed enterally, the current standard is to initially place an NG tube and leave it in place for the first few months of supplemental or total enteral nutrition. It is important to understand if placement of NG tubes has a negative effect on a patient’s swallow.

Methods

We retrospectively reviewed the charts of those children who had videofluoroscopic swallow studies (VFSS) to identify all children who had an NG tube in place at the time of swallow study. Age and sex matched children were identified who had undergone VFSS without an NG in place. These charts were reviewed for diagnosis at the time of the VFSS and presence or absence of aspiration or laryngeal penetrations.

Results

Sixty-three children with NG tubes were identified, along with 63 age and sex matched children without NG tubes in place, at the time of VFSS. Ages ranged from 7 days to 13 years. The NG group had a significantly higher proportion demonstrating aspiration (46% vs. 23.8%, p = 0.0089).

Conclusions

This study supports the need for further prospective evaluation of NG tubes and their effect on swallow, as well as more careful consideration of prolonged NG tube placement in patients with feeding problems. Consideration should be given to removal of the NG prior to VFSS to prevent the impact of NG placement on results of the swallow study which could lead to inappropriate modifications to the patient’s care plan.

A computational fluid dynamics simulation of liquid swallowing by impaired pharyngeal motion: bolus pathway and pharyngeal residue

Common practices to improve the ability to swallow include modifying physical properties of foods and changing the posture of patients. Here, we quantified the effects of the viscosity of a liquid bolus and patient posture on the bolus pathway and pharyngeal residue using a computational fluid dynamics simulation. We developed a computational model of an impaired pharyngeal motion with a low pharyngeal pressure and no pharyngeal adaptation. We varied viscosities from 0.002 to 1 Pa·s and postures from -15° to 30° (from nearly vertical to forward leaning). In the absence of pharyngeal adaptation, a honey-like liquid bolus caused pharyngeal residue, particularly in the case of forward-leaning postures. Although the bolus speed was different among viscosities, the final pathway was only slightly different. The shape, location, and tilting of the epiglottis effectively invited a bolus to two lateral pathways, suggesting a high robustness of the swallowing process.NEW & NOTEWORTHY Thickening agents are often used for patients with dysphagia. An increase in bolus viscosity not only reduces the risk of aspiration but also can cause a residual volume in the pharynx. Because information obtained from videofluoroscopic swallowing studies is only two-dimensional, measurement of pharyngeal residue is experimentally difficult. We successfully quantified the three-dimensional bolus pathway and the pharyngeal residual volume using computational modeling and simulation.

Experimental and Computational Investigation of the IDDSI Flow Test of Liquids Used in Dysphagia Management

The International Dysphagia Diet Standardisation Initiative (IDDSI) flow test, using a standard 10-mL syringe, is being adopted in many countries for clinical measurement of the consistency of drinks. The working hypothesis is that thickening drinks to retard flow can be advantageous for individuals who struggle to cope with thin drinks. This study assesses how the IDDSI test relates to rheology and clinical knowledge of physiological flows during swallowing. With no pre-existing analytical solution for internal flow through the syringe, a computational model was designed, incorporating rheometry data from a variety of Newtonian and non-Newtonian liquids. The computational model was validated experimentally across the range of liquids but the technique showed limitations in simulating dripping and cohesiveness. Gum-based liquids which were strongly shear-thinning (0.12 < n < 0.25) showed plug-flow characteristics with 90% of the shear occurring in only 22% of the radial dimension. Shear rates were maximal at the nozzle outlet (> 60 times higher than the barrel) and reached 7400/s for the thinnest gum-based liquid. Shear rheology data alone was unable to describe the flow of these drinks. The flow conditions in the test varied according to the type and consistency of liquid, relating to the desired clinical effect.

Application of Automatic Kinematic Analysis Program for the Evaluation of Dysphagia in ALS patients

Dysphagia in amyotrophic lateral sclerosis (ALS) increases the risk of malnutrition, dehydration, and aspiration pneumonia. Kinematic analysis of videofluoroscopic swallowing study (VFSS) can provide detailed movement of the hyoid bone, revealing abnormalities of swallowing in ALS patients. We developed an automated kinematic analysis program (AKAP) that analyzes the trajectory of the hyoid bone via a visual tracking method. The aim of this study was to investigate the hyoid movement in ALS patients using AKAP and compare it with non-dysphagic subjects. Thirty ALS patients who underwent VFSS in Seoul National University Bundang Hospital between 2015 and 2017 were recruited. For comparison, 30 age-matched control subjects were also enrolled; the same swallowing study was conducted using thin fluid and yogurt. The hyoid bone movement was analyzed by evaluating the vertical and horizontal distances with four peak points (A, B, C, D), and the time of each point were also calculated. With respect to distance parameters, only vertical peak distance (distance between B, D points) during thin fluid swallowing was significantly decreased in ALS patients. (p = 0.038) With respect to temporal parameters, Time ABC, Time ABCD, and Duration C were significantly increased in ALS patients when swallowing both thin fluid and yogurt. (Time ABC p = 0.019, p = 0.002; Time ABCD p = 0.001, p = 0.004; Duration C p = 0.004, p = 0.025 respectively). This result revealed that dysphagia in ALS patient is caused by decreased velocity of hyoid bone movement due to the development of weakness in swallowing-related muscles. The parameters of kinematic analysis could be used to quantitatively evaluate dysphagia in motor neuron disease.

Relationship between oral transit time and functional performance in motor neuron disease

Oral phase swallowing impairment in motor neuron disease (MND) is caused by tongue weakness, fasciculation and atrophy, which may compromise oral transit time and total feeding time. OBJECTIVE To describe and correlate total oral transit time (TOTT) with functional performance in MND using different food consistencies. METHODS The study was conducted on 20 patients with MND, regardless of type or duration of the disease, of whom nine were excluded due to issues on the videofluoroscopic swallowing images. The remaining 11 patients (nine men and two women) ranged from 31 to 87 years of age (mean: 57 years) with scores on the Penetration Aspiration Scale ranging from ≤ 2 to ≤ 4. The Amyotrophic Lateral Sclerosis Functional Rating Scale - revised questionnaire was applied to classify individuals according to global, bulbar and bulbar/respiratory parameters. Videofluoroscopy of swallowing using 5ml of different consistencies was performed and a quantitative temporal analysis of the TOTT was carried out with the aid of specific software. RESULTS There was a wide variation in the TOTT within the same food consistency among MND patients. There was a correlation between the TOTT and overall functional performance for the thickened liquid consistency (r = -0.691) and between the TOTT and bulbar performance for the pureed consistency (r = -0.859). CONCLUSION Total oral transit time in MND varies within the same food consistency and the longer the TOTT, regardless of food consistency, the lower the functional performance in MND.

Feasibility of high-resolution manometry for decision of feeding methods in patients with amyotrophic lateral sclerosis

As amyotrophic lateral sclerosis (ALS) progresses, dysphagia gets worse due to the weakening of pharyngeal musculature. As oral feeding becomes more difficult or dangerous due to worsening dysphagia, tracheal aspiration, or undernutrition, the necessity for tube feeding becomes increasingly important. This study aims to establish a standard pressure point by applying pharyngeal pressure using high-resolution manometry (HRM) to start tube feeding in patients with ALS.This study was designed as a retrospective analysis of prospectively collected data. Forty-one patients with ALS and 20 healthy subjects were participated. Both groups were evaluated using HRM, videofluoroscopic swallowing study (VFSS), and pulmonary function test. The swallowing pressure along the velopharynx (VP), tongue base (TB), pre-upper esophageal sphincter (UES), lower pharynx, and cricopharyngeus, as well as minimal UES pressure were measured using HRM.There was significantly positive correlation between the pressure of cricopharyngeus and forced expiratory volume in 1 second (FEV1). And there were significant correlations between results of VFSS and FEV1, FEV1%, forced vital capacity (FVC), and FVC%. There was a significant difference in the pressure of TB and cricopharyngeus between the control group and the ALS patient group. The pressures of VP, TB, lower pharynx, and cricopharyngeus have a significant correlation with the recommended feeding type by VFSS.Because it is possible to use HRM to quantitatively assess pharyngeal and respiratory weaknesses and it is more sensitive than other evaluation tools, the cutoff value of HRM parameters may be used to decide the feeding type in patients with ALS.

The association between temporal measures of swallowing with penetration and aspiration in patients with dysphagia: A meta-analysis

INTRODUCTION

Temporal features of swallowing physiology vary with age in healthy normals and have the potential to impact swallow safety and efficiency in patients with dysphagia. We conducted a meta-analysis to assess the relation between temporal features of swallowing with penetration, aspiration and residue in adult patients with dysphagia regardless of etiology.

METHODS

Operational definitions of relevant terms were defined a priori. A search of 5 databases was conducted to November 2016 without restriction to language. Two independent raters reviewed abstracts and full articles, with discrepancies resolved by consensus. All accepted articles advanced to data extraction and critical appraisal according to Cochrane standards. Analysis of pooled data compared measures between groups.

RESULTS

Of the 11 articles accepted, the temporal measures used in three or more studies were grouped into morphofunctional categories: bolus transit time; pharyngeal response time; laryngeal closure time; and upper esophageal opening time. Across all selected articles, definitions varied for abnormal swallow and only 4 articles reported rater blinding and reliability for measures related to timing. Pooled data identified two main findings: a. longer pharyngeal response time was associated with penetration and/or aspiration (MD = 0.40 95% CI 0.59 - 0.22), and longer upper esophageal opening duration was associated with only aspiration (PAS ≥ 6) (MD = 0.09 95% CI 0.16 - 0,02). No studies were found that related temporal measures and residue.

CONCLUSION

Our pooled findings identified an association of two temporal measures with penetration and/or aspiration but none with residue. The current evidence remains limited due to the heterogeneity across studies in how swallow measures were operationalized. Future work with a standardized and reproducible approach is direly needed.

Video fluoroscopic techniques for the study of Oral Food Processing

Food oral processing and pharyngeal food passage cannot be observed directly from the outside of the body without instrumental methods. Videofluoroscopy (x-ray video recording) reveals the movement of oropharyngeal anatomical structures in two dimensions. By adding a radiopaque contrast medium, the motion and shape of the food bolus can be also visualized, providing critical information about the mechanisms of eating, drinking, and swallowing. For quantitative analysis of the kinematics of oral food processing, radiopaque markers are attached to the teeth, tongue or soft palate. This approach permits kinematic analysis with a variety of textures and consistencies, both solid and liquid. Fundamental mechanisms of food oral processing are clearly observed with videofluoroscopy in lateral and anteroposterior projections.

Proposed Use of Thickener According to Fluid Intake on Videofluoroscopic Swallowing Studies: Preliminary Study in Normal Healthy Persons

OBJECTIVE

To examine the characteristics and changes in the pharyngeal phase of swallowing according to fluid viscosity in normal healthy persons, to help determine fluid intake methods in more detail than the use of standardized fluid.

METHODS

This was a prospective observational study involving 10 normal healthy adults. While the participants sequentially took in fluids with 10 different viscosities changes in the pharyngeal phase of the swallowing process were monitored using videofluoroscopic swallowing studies (VFSS). Twenty parameters of the pharyngeal phase, including epiglottis contact, laryngeal elevation, pharyngeal constriction, and upper esophageal sphincter opening, were determined and compared.

RESULTS

No significant viscosity-based changes in epiglottis contact, laryngeal elevation, or upper esophageal sphincter-opening duration of the pharyngeal phase were observed. However, pharyngeal transit time and time from the start of the pharyngeal phase to peak pharyngeal constriction were significantly delayed upon intake of fluid with viscosities of 150.0 centipoise (cP) and 200.0 cP.

CONCLUSION

VFSS analysis of fluid intake may require the use of fluids of various concentrations to determine a suitable viscosity of thickener mixture for each subject.

The Effects of Bolus Volume and Texture on Pharyngeal Pressure Events Using High-resolution Manometry and Its Comparison with Videofluoroscopic Swallowing Study

Background/Aims

The purpose of this study was to develop new parameters of high-resolution manometry (HRM) and to applicate these to quantify the effect of bolus volume and texture on pharyngeal swallowing.

Methods

Ten healthy subjects prospectively swallowed dry, thin fluid 2 mL, thin fluid 5 mL, thin fluid 10 mL, and drinking twice to compare effects of bolus volume. To compare effect of texture, subjects swallowed thin fluid 5 mL, yogurt 5 mL, and bread twice. A 32-sensor HRM catheter and BioVIEW ANALYSIS software were used for data collection and analysis. HRM data were synchronized with kinematic analysis of videofluoroscopic swallowing study (VFSS) using epiglottis tilting.

Results

Linear correlation analysis for volume showed significant correlation for area of velopharynx, duration of velopharynx, pre-upper esophageal sphincter (UES) maximal pressure, minimal UES pressure, UES activity time, and nadir UES duration. In the correlation with texture, all parameters were not significantly different. The contraction of the velopharynx was faster than laryngeal elevation. The durations of UES relaxation was shorter in the kinematic analysis than HRM.

Conclusions

The bolus volume was shown to have significant effect on pharyngeal pressure and timing, but the texture did not show any effect on pharyngeal swallowing. The parameters of HRM were more sensitive than those of kinematic analysis. As the parameters of HRM are based on precise anatomic structure and the kinematic analysis reflects the actions of multiple anatomic structures, HRM and VFSS should be used according to their purposes.

Effect of Bolus Viscosity on the Safety and Efficacy of Swallowing and the Kinematics of the Swallow Response in Patients with Oropharyngeal Dysphagia: White Paper by the European Society for Swallowing Disorders (ESSD)

BACKGROUND

Fluid thickening is a well-established management strategy for oropharyngeal dysphagia (OD). However, the effects of thickening agents on the physiology of impaired swallow responses are not fully understood, and there is no agreement on the degree of bolus thickening.

AIM

To review the literature and to produce a white paper of the European Society for Swallowing Disorders (ESSD) describing the evidence in the literature on the effect that bolus modification has upon the physiology, efficacy and safety of swallowing in adults with OD.

METHODS

A systematic search was performed using the electronic Pubmed and Embase databases. Articles in English available up to July 2015 were considered. The inclusion criteria swallowing studies on adults over 18 years of age; healthy people or patients with oropharyngeal dysphagia; bolus modification; effects of bolus modification on swallow safety (penetration/aspiration) and efficacy; and/or physiology and original articles written in English. The exclusion criteria consisted of oesophageal dysphagia and conference abstracts or presentations. The quality of the selected papers and the level of research evidence were assessed by standard quality assessments.

RESULTS

At the end of the selection process, 33 articles were considered. The quality of all included studies was assessed using systematic, reproducible, and quantitative tools (Kmet and NHMRC) concluding that all the selected articles reached a valid level of evidence. The literature search gathered data from various sources, ranging from double-blind randomised control trials to systematic reviews focused on changes occurring in swallowing physiology caused by thickened fluids. Main results suggest that increasing bolus viscosity (a) results in increased safety of swallowing, (b) also results in increased amounts of oral and/or pharyngeal residue which may result in post-swallow airway invasion, (c) impacts the physiology with increased lingual pressure patterns, no major changes in impaired airway protection mechanisms, and controversial effects on oral and pharyngeal transit time, hyoid displacements, onset of UOS opening and bolus velocity-with several articles suggesting the therapeutic effect of thickeners is also due to intrinsic bolus properties, (d) reduces palatability of thickened fluids and (e) correlates with increased risk of dehydration and decreased quality of life although the severity of dysphagia may be an confounding factor.

CONCLUSIONS

The ESSD concludes that there is evidence for increasing viscosity to reduce the risk of airway invasion and that it is a valid management strategy for OD. However, new thickening agents should be developed to avoid the negative effects of increasing viscosity on residue, palatability, and treatment compliance. New randomised controlled trials should establish the optimal viscosity level for each phenotype of dysphagic patients and descriptors, terminology and viscosity measurements must be standardised. This white paper is the first step towards the development of a clinical guideline on bolus modification for patients with oropharyngeal dysphagia.

Findings of Abnormal Videofluoroscopic Swallowing Study Identified by High-Resolution Manometry Parameters

OBJECTIVE

To identify the parameters of high-resolution manometry (HRM) with a significant correlation to abnormal findings of videofluoroscopic swallowing study (VFSS).

DESIGN

Prospective study.

SETTING

Hospital rehabilitation department.

PARTICIPANTS

Patients with dysphagia symptoms (N=40).

INTERVENTION

Participants were evaluated once using VFSS in neutral head position and evaluated twice using HRM with 5mL of thin fluid.

MAIN OUTCOME MEASURES

HRM parameters included maximal pressure, area integral, rise time, duration of the velopharynx and tongue base, maximal pressure of pre-upper esophageal sphincter (UES), low pharynx, cricopharyngeus, minimal UES pressure, UES activity time, and nadir UES duration. HRM parameters were compared with the findings of VFSS. Receiver operating characteristic analysis was performed to obtain the cutoff value, sensitivity, and specificity of HRM parameters for the prediction of findings of VFSS.

RESULTS

The maximum pressure of the velopharynx showed a significantly positive prediction for most abnormal parameters of VFSS in the pharyngeal phase. Nadir UES pressure duration was significant for impaired laryngeal elevation, residue at pyriformis sinus, and combination of penetration and aspiration. The maximum pressure of the velopharynx <180.0 showed 100% sensitivity and 75% specificity for the presence of penetration and aspiration, and the cutoff point of 178.8 showed 86.7% sensitivity and 75% specificity for the presence of subglottic aspiration.

CONCLUSIONS

This study identified significant HRM parameters that are highly specific for individual abnormalities of VFSS, suggesting the cutoff value, sensitivity, and specificity. Because HRM could inform the quantitative measurement of pharyngeal weakness, the cutoff value for HRM parameters could be used to predict aspiration in patients with pharyngeal weakness.

Oral perception of liquid volume changes with age

Bolus volume has been widely studied, and research has demonstrated a variety of physiological impacts on swallowing and swallowing disorders. Oral perception of bolus volume has not, to our knowledge, been investigated in association with normal ageing processes. Research suggests many sensory changes with age, some within the oral cavity, and changes in swallowing function with age have been defined. The role of perception in oropharyngeal deglutition with age requires further investigation. The purpose of this study was to establish the psychophysical relationship between liquid volume and oral perception and examine changes with age. Healthy young and older adults were prospectively assessed using a magnitude estimation task differentiating five volumes of water delivered randomly to the oral cavity. Results suggest a fourfold increase in liquid volume is required by older participants to perceive an approximate twofold increase in the perception of volume compared with younger healthy adults. Sensory receptors in the oral cavity provide a feedback loop that modulates the swallowing motor response so that it is optimal for the size and consistency of the bolus. Changes in perception of bolus volume with age are consistent with other perceptual changes and may provide valuable information regarding sensorineural rehabilitation strategies in the future.

Correlation varies with different time lags between the motions of the hyoid bone, epiglottis, and larynx during swallowing

Although coordination and timing of swallowing have often been investigated by using discrete timing events such as the onset, peak, and duration of specific motions, the sequence and duration of swallowing events cannot represent the coordination of the swallowing mechanism quantitatively. This study aimed to apply a cross-correlation analysis of the motions of the hyolaryngeal structures during swallowing as an objective method for measuring the coordination and timing of the motions. Forty healthy subjects swallowed 2 and 5 ml of diluted barium solution (35 %) and 5 ml of curd yogurt under videofluoroscopy. Hyolaryngeal motions in videofluoroscopic images were digitized using the motion analysis system. The time series of the horizontal and vertical hyoid motion, the laryngeal elevation, and the angle of the epiglottic tilt were analyzed using cross-correlation at each 1/60-s time lag. The results showed high and consistent cross-correlations between hyolaryngeal motions during swallowing in most of the subjects regardless of age and bolus type. The horizontal hyoid motion and laryngeal elevation were more strongly correlated with the epiglottic tilt than the vertical hyoid motion, which might suggest the mechanism of the epiglottic tilt during swallowing. The bolus volume and viscosity affected the correlation coefficients and time lags between the hyolaryngeal motions, particularly those related to the epiglottic tilt. The results suggest that cross-correlation analysis may be used for measuring the coordination and timing of swallowing. Further studies using cross-correlation analysis of additional physiological factors related to swallowing or pathological conditions are warranted.

Dysphagia: implications for older people

Dysphagia represents a salient concern in many conditions prevalent in older people. There are direct implications for morbidity and mortality. The importance of recognizing and managing dysphagia in hospital and the community also extends to psychosocial impact and quality of life, as well as health, economic and ethical-legal issues. This review outlines reasons for the importance of recognizing and treating dysphagia. It then proceeds to look at recent developments in our understanding of the nature, assessment and management of dysphagia in older people. Whilst there are well-established practices in assessment and management, ongoing work continues to challenge the validity and reliability of many methods. These concerns are covered and directions for future developments highlighted.

Sucking and swallowing rates after palatal anesthesia: an electromyographic study in infant pigs

Infant mammalian feeding consists of rhythmic suck cycles and reflexive pharyngeal swallows. Although we know how oropharyngeal sensation influences the initiation and frequency of suck and swallow cycles, the role of palatal sensation is unknown. We implanted EMG electrodes into the mylohyoid muscle, a muscle active during suckling, and the thyrohyoid muscle, a muscle active during swallowing, in eight infant pigs. Pigs were then bottle-fed while lateral videofluoroscopy was simultaneously recorded from the electrodes. Two treatments were administered prior to feeding and compared with control feedings: 1) palatal anesthesia (0.5% bupivacaine hydrochloride), and 2) palatal saline. Using the timing of mylohyoid muscle and thyrohyoid muscle activity, we tested for differences between treatment and control feedings for swallowing frequency and suck cycle duration. Following palatal anesthesia, four pigs could not suck and exhibited excessive jaw movement. We categorized the four pigs that could suck after palatal anesthesia as group A, and those who could not as group B. Group A had no significant change in suck cycle duration and a higher swallowing frequency after palatal saline (P = 0.021). Group B had significantly longer suck cycles after palatal anesthesia (P < 0.001) and a slower swallowing frequency (P < 0.001). Swallowing frequency may be a way to predict group membership, since it was different in control feedings between groups (P < 0.001). The qualitative and bimodal group response to palatal anesthesia may reflect a developmental difference. This study demonstrates that palatal sensation is involved in the initiation and frequency of suck and swallow cycles in infant feeding.