A novel method for the nonradiological assessment of ineffective swallowing

Pharyngeal electrical stimulation favorably modifies healthy human pharyngoesophageal function: a randomized trial using high-resolution manometry impedance

Despite positive clinical evidence for the effects of pharyngeal electrical stimulation (PES) on swallowing performance in disease, it remains unknown which specific swallow characteristics improve. Using high-resolution manometry impedance (HRMI) with pressure flow analysis (PFA), we aimed to assess the effects of PES on normal swallow function and to evaluate the impact of pharyngeal length variability on electrode placement. As part of a prospective randomized controlled trial (RCT), 20 asymptomatic volunteers were randomly assigned to 3 days of PES or SHAM treatment. HRMI assessments were conducted at baseline (during which pharyngeal length measurements were acquired) and repeated at 1-2 h, and at 24-72 h following PES or SHAM treatment. Twenty healthy adults [10 males, median age: 28.0 (interquartile range, IQR 23.8-45.0) yr, age range: 20-65 yr] participated in this RCT. We developed an objective, standardized method of catheter placement based on pharyngeal length measurements. Over 3 days, the median stimulation intensity of PES was 11 mA. When compared with the SHAM group, the PES group scored better on multiple pharyngeal and esophageal metrics resulting in improved global swallow function values 1-2 h after treatment (P = 0.029). One day later, most of these beneficial effects were no longer present. This study suggests that PES can temporarily alter swallow function in healthy individuals. Functional reserve in healthy individuals may be further enhanced by PES. In the majority of volunteers, electrode position needed to be adjusted 1-3 cm to account for variations in pharyngeal length.NEW & NOTEWORTHY Pharyngeal electrical stimulation (PES) positively influences clinical swallow-outcomes in patients with neurogenic dysphagia. Its effect on the underlying swallowing physiology remains unknown. Our study evaluated this effect of PES in healthy individuals using high-resolution manometry impedance. PES showed short-term improved pharyngeal contractility, upper esophageal sphincter relaxation, proximal esophageal contractility and bolus flow, resulting in improved swallowing. One day later, most of these beneficial effects were no longer present as expected in already intact swallow systems.

Effect of Thickened Fluids on Swallowing Function in Oropharyngeal Dysphagia: Impact of Shear Rheology and Disorder Subtype

INTRODUCTION

Fluid thickeners used in the management of oropharyngeal dysphagia exhibit non-Newtonian shear-thinning rheology, impacting their viscosity during deglutition. This study investigated how the rheological properties of thickened fluids affect pharyngeal swallowing parameters in patients with oropharyngeal motor disorders diagnosed by pharyngeal high-resolution manometry impedance (P-HRM-I).

METHODS

Seventy-two patients (18-89 years) referred for P-HRM-I were diagnostically assessed with a 10 mL thin bolus. In 57 of the patients, 10 mL swallows of two moderately thick formulations-xanthan gum (XG) and sodium carboxymethylcellulose gum (CMC)-were also tested. The XG and CMC fluids had equivalent empirical thickness but different viscosity at pharyngeal phase shear rates: XG 87 mPa.s (83-91) versus CMC mean 157 mPa.s (148-164) at 300 s-1. Standard metrics of pharyngeal and upper esophageal sphincter (UES) function were derived from P-HRM-I recordings and analyzed to characterize patients into one of four disorder subtypes: (i) No Disorder, (ii) UES Disorder, (iii) Pharyngeal Disorder, and (iv) Combination UES/Pharyngeal Disorder. Impedance recordings also assessed pharyngeal bolus transit.

RESULTS

Patients with a Combination UES/Pharyngeal Disorder were most likely to have abnormal bolus transit (82%, p < 0.001). Increasing bolus viscosity significantly influenced UES residual pressure, UES opening area, and post-swallow residue. Patients with UES Disorder exhibited pronounced increases in UES residual pressure with CMC compared to XG. Pharyngeal contractility was unaffected by viscosity changes. Post-swallow residue increased with CMC, particularly in patients with a Combination Disorder. Case-by-case analysis revealed individual variability in response to the different viscosities.

CONCLUSION

The rheological properties of thickened fluids significantly affect swallowing function, with these effects dependent upon the disorder subtype.

Neural-Mediated Laryngopharyngeal Reflux Disease and the Role of Esophageal Dysmotility

The diagnosis and management of laryngopharyngeal reflux (LPR) remain challenging due to complex pathophysiological interactions, including autonomic nerve dysfunction and impaired esophageal motility. The lack of definitive diagnostic tools, insufficient exclusion of alternative causes, and variability in study design and methodology often lead to inconsistent treatment responses and suboptimal outcomes. Functional laryngeal disorders and hypersensitivity further complicate accurate diagnosis and management. High-resolution manometry, combined with multichannel impedance testing, has highlighted the role of esophageal dysmotility in LPR symptoms. This article focuses on the neural-mediated mechanisms and esophageal dysmotility contributing to LPR.

The Use of Pharyngeal High-Resolution (Impedance) Manometry in Patients With Head and Neck Cancer: A Scoping Review

PURPOSE

This scoping review aims to summarize and explore current literature on the usefulness and clinical implications of pharyngeal high-resolution (impedance) manometry (HRM/HRIM) in head and neck cancer (HNC) patients.

METHOD

Three online databases (MEDLINE, Embase, Scopus, and additionally Google Scholar) were searched until December 2023. Studies using pharyngeal HRM/HRIM to assess swallowing or voicing in HNC patients, written in any language and published in peer-reviewed journals, were considered eligible. Quality check was performed using the Quality Assessment Tool for Quantitative Studies from the Effective Public Healthcare Practice Project. Information about the study population and HRM/HRIM data (equipment, protocol, analysis, and outcomes) were extracted.

RESULTS

Eight papers met the inclusion criteria, six utilizing HRM and two HRIM. The study design consisted of case-series (five) and case-control (three). The quality assessment indicated a weak global rating for seven papers and a moderate rating for one for the remaining study. Findings suggest that HNC patients with dysphagia suffer from reduced pressures in the pharynx and upper esophageal sphincter compared to healthy individuals, potentially influenced by tumor characteristics and treatment. Decreased pressures may indicate poor functioning of swallowing musculature and mechanism.

CONCLUSIONS

Pharyngeal HRM/HRIM is sparsely used for swallowing assessment in HNC patients. However, wider use seems warranted, as it can offer valuable insights into swallowing biomechanics. This can help quantifying the degree and timing of pressures involved in swallowing (problems) and holds potential for clinical applications, such as earlier diagnosis of radiation-induced therapy or surgery complications. Additionally, it can be beneficial in evaluating therapeutic swallowing strategies.

Swallowing biomechanics in tracheostomised critically ill patients compared to age- and gender-matched healthy controls

Objective

The mechanistic effects of a tracheostomy on swallowing are unclear. Pharyngeal high-resolution manometry with impedance (P-HRM-I) is a novel swallow assessment tool providing quantifiable metrics. This study aimed to characterise swallowing biomechanics in tracheostomised critically ill (non-neurological) patients.

Design

Cohort study.

Setting

Australian tertiary hospital intensive care unit.

Participants

Tracheostomised adults, planned for decannulation.

Main outcome measures

Swallowing assessment using P-HRM-I, compared to healthy age- and gender-matched controls.

Results

In this tracheostomised cohort (n = 10), the Swallow Risk Index, a global measure of swallow function, was significantly elevated (p < 0.001). At the upper oesophageal sphincter (UOS), hypopharyngeal intrabolus pressure and UOS integrated relaxation pressure were significantly elevated (control 0.65 mmHg [-1.02, 2.33] v tracheostomy 13.7 mmHg [10.4, 16.9], P < 0.001; control -4.28 mmHg [-5.87, 2.69] v tracheostomy 12.2 mmHg [8.83, 15.6], P < 0.001, respectively). Furthermore, UOS opening extent and relaxation time were reduced (control 4.83 mS [4.60, 5.07] v tracheostomy 4.33 mS [3.97, 4.69], P = 0.002; control 0.52 s [0.49, 0.55] v tracheostomy 0.41 s [0.37, 0.45], P < 0.001, respectively). Total pharyngeal contractility (PhCI) measuring pharyngeal pressure generation was significantly elevated (control 199.5 mmHg cm.s [177.4, 221.6] v tracheostomy 326.5 mmHg cm.s [253.3, 399.7]; P = 0.001).

Conclusion

In a critically ill tracheostomised cohort, UOS dysfunction was the prevalent biomechanical feature, with elevated pharyngeal pressures. Pharyngeal weakness is not contributing to dysphagia in this cohort. Instead, elevated pharyngeal pressures may represent a compensatory mechanism to overcome the UOS dysfunction. Further studies to extend these findings may inform the development of timely and targeted rehabilitation.

Swallowing Problems in Spinal Muscular Atrophy Types 2 and 3: A Clinical, Videofluoroscopic and Ultrasound Study

Background: Spinal muscular atrophy (SMA) is a hereditary motor neuron disorder, characterized by the degeneration of motor neurons and progressive muscle weakness. There is a large variability of disease severity, reflected by the classification of SMA types 1–4. Objective: The aim of this cross-sectional study was to determine the nature of swallowing problems and underlying mechanisms in patients with SMA types 2 and 3, and the relationship between swallowing and mastication problems. Methods: We enrolled patients (aged 13–67 years) with self-reported swallowing and/or mastication problems. We used a questionnaire, the functional oral intake scale, clinical tests (dysphagia limit, and timed test swallowing, the test of mastication and swallowing solids), a videofluoroscopic swallowing study (VFSS), and muscle ultrasound of the bulbar muscles (i.e. digastric, geniohyoid and tongue muscles). Results: Non-ambulant patients (n = 24) had a reduced dysphagia limit (median 13 ml (3–45), and a swallowing rate at the limit of normal (median 10 ml/sec (range 4–25 ml). VFSS revealed piecemeal deglutition and hypo-pharyngeal residue. We found pharyngo-oral regurgitation in fourteen patients (58%), i.e. they transported the residue from the hypopharynx back into the oral cavity and re-swallowed it. Six patients (25%) demonstrated impaired swallowing safety (i.e. PAS >3). Muscle ultrasound revealed an abnormal muscle structure of the submental and tongue muscles. Ambulant patients (n = 3), had a normal dysphagia limit and swallowing rate, but VFSS showed hypo-pharyngeal residue, and muscle ultrasound demonstrated an abnormal echogenicity of the tongue. Swallowing problems were associated with mastication problems (p = 0.001).

Bolus Clearance Ratio Elevated in Patients With Neurogenic Dysphagia Compared With Healthy Adults: A Measure of Pharyngeal Efficiency

PURPOSE

Postswallow pharyngeal residue is a risk factor for aspiration, implies swallowing inefficiency, and increases the work of eating. The Bolus Clearance Ratio (BCR) is a derived metric that relates quantities of bolus material observed in the pharynx at two different points: before and after a swallow. The ratio provides a percentage estimate of bolus clearance. In healthy adults, mean BCR is < .05; that is, less than 5% of an ingested bolus is retained in the pharynx. The aim of this study was to compare BCR measures from patients referred for videofluoroscopic swallow studies with concerns related to stroke (n = 100) or other neurological conditions (n = 131, including Parkinson's disease and dementia) with BCRs for 139 healthy adults across the age range.

METHOD

BCR for a 20 ml of thin liquid barium bolus was measured. Additional metrics included age, penetration-aspiration scale (PAS) score, and quantitative measures of timing and displacement. Correlations were explored between BCR and pharyngeal constriction ratio (PCR), pharyngoesophageal segment opening (PESmax), maximum hyoid displacement (HMax), and total pharyngeal transit time (TPT).

RESULTS

BCR values for patients with stroke (Mdn = 9%, interquartile range [IQR]: 19%, range: 0%-73%) and other neurological conditions (Mdn = 9%, IQR: 16%, range: 0%-96%) were significantly higher than in healthy norms (Mdn = 2%, IQR: 4%, range: 0%-16%, p < .001). BCR was significantly correlated with age (R _s = .23, p < .01), TPT (R _s = .20, p < .01), PCR (R _s = .55, p < .01), PESmax (R _s = -.17, p < .01), HMax (R _s = -.16, p < .01), and PAS (R _s = .38, p < .01).

CONCLUSIONS

BCR was elevated in patients with neurogenic dysphagia in comparison with healthy norms and was significantly associated with increased aspiration severity (i.e., PAS). BCR was also correlated with pharyngeal timing and displacement parameters, with the strongest correlation with pharyngeal constriction-a measure of pharyngeal strength. The BCR offers clinicians a simple, quantitative measure of bolus residue and, therefore, pharyngeal efficiency and may be used to assess change in patients over time and with treatment.

Accuracy of High-Resolution Pharyngeal Manometry Metrics for Predicting Aspiration and Residue in Oropharyngeal Dysphagia Patients with Poor Pharyngeal Contractility

Several physiological metrics can be derived from pharyngeal high-resolution impedance manometry (HRPM), but their clinical relevance has not been well established. We investigated the diagnostic performance of these metrics in relation to videofluoroscopic (VFS) assessment of aspiration and residue in patients with oropharyngeal dysphagia. We analyzed 263 swallows from 72 adult patients (22-91 years) with diverse medical conditions. Metrics of contractility, upper esophageal sphincter (UES) opening and relaxation, flow timing, intrabolus distension pressure, and a global Swallow Risk Index (SRI) were derived from pressure-impedance recordings using pressure-flow analysis. VFS data were independently scored for airway invasion and pharyngeal residue using the Penetration-Aspiration Scale and the Normalized Residue Ratio Scale, respectively. We performed multivariate logistic regression analyses to determine the relationship of HRPM metrics with radiological outcomes and receiver-operating characteristic (ROC) analysis to evaluate their diagnostic accuracy. We identified aspiration in 25% and pharyngeal residue in 84% of the swallows. Aspiration was independently associated with hypopharyngeal peak pressure < 65 mmHg (HypoPeakP) [adjusted odds ratio (OR) 5.27; 95% Confidence Interval (CI) (0.99-28.1); p = 0.051], SRI > 15 [OR 4.37; 95% CI (1.87-10.2); p < 0.001] and proximal esophageal contractile integral (PCI) < 55 mmHg·cm·s [OR 2.30; 95% CI (1.07-4.96); p = 0.034]. Pyriform sinus residue was independently predicted by HypoPeakP < 65 mmHg [OR 7.32; 95% CI (1.93-27.7); p = 0.003], UES integrated relaxation pressure (UES-IRP) > 3 mmHg [OR 2.96; 95% CI (1.49-5.88); p = 0.002], and SRI > 15 [OR 2.17; 95% CI (1.04-4.51); p = 0.039]. Area under ROC curve (AUC) values for individual HRPM metrics ranged from 0.59 to 0.74. Optimal cut-off values were identified. This study demonstrates the diagnostic value of certain proposed and adjunct HRPM metrics for identifying signs of unsafe and inefficient bolus transport in patients with oropharyngeal dysphagia.

Comparison of Validated Videofluoroscopic Outcomes of Pharyngeal Residue: Concordance Between a Perceptual, Ordinal, and Bolus-Based Rating Scale and a Normalized Pixel-Based Quantitative Outcome

PURPOSE

This study compared the concordance between two validated videofluoroscopic pharyngeal residue outcome scales used in clinical and research settings: the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) and the Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) percent residue metric.

METHOD

Two trained raters completed independent and blinded videofluoroscopic ratings of both DIGEST efficiency and ASPEKT percent pharyngeal residue outcomes for bolus trials of 5 cc Varibar thin liquid (n = 223), thin liquid comfortable cup sips (n = 223), and 5 cc Varibar thin honey (n = 223). Spearman's rho and Kruskal-Wallis analyses were performed for each bolus type.

RESULTS

Significant associations between DIGEST and ASPEKT pharyngeal residue outcomes were noted for 5 cc thin (r = .54, p < .001), cup sip thin (r = .41, p < .001), and 5 cc thin honey (r = .60, p < .001) bolus trials. ASPEKT percent residue increased across worsening DIGEST efficiency ordinal scale levels, with a main effect for each bolus type. Post hoc analysis revealed significant differences in the ASPEKT percent residue values between each DIGEST pairwise comparison for the thin cup sip bolus trial and for each pairwise comparison except between the moderate-to-severe (less than half vs. majority) ordinal levels for the 5 cc thin and 5 cc honey bolus trials, p < .05.

CONCLUSIONS

Perceptual, ordinal (DIGEST) and quantitative, pixel-based (ASPEKT) videofluoroscopic pharyngeal residue outcomes were associated in this data set of 669 bolus trials. Future research is warranted to confirm these results.

Quantifying Bolus Residue and Its Risks in Children: A Videofluoroscopic Study

Purpose Postswallow residue is a clinical sign of swallow impairment and has shown a strong association with aspiration. Videofluoroscopy (videofluoroscopic study of swallowing [VFSS]) is commonly used to visualize oropharyngeal swallowing and to identify pharyngeal residue. However, subjective binary observation (present or absent) fails to provide important information on volume or location and lacks objectivity and reproducibility. Reliable judgment of changes in residue over time and with treatment is therefore challenging. We aimed to (a) determine the reliability of quantifying pharyngeal residue in children using the bolus clearance ratio (BCR), (b) determine associations between BCR and other timing and displacement measures of oropharyngeal swallowing, and (c) explore the association between BCR and penetration-aspiration in children. Method In this single-center retrospective observational study, we obtained a set of quantitative and descriptive VFSS measures from 553 children (0-21 years old) using a standard protocol. VFSS data were recorded at 30 frames per second for quantitative analysis using specialized software. Results Good interrater (ICC = .86, 95% CI [.74, .961], p < .001) and excellent intrarater reliability was achieved for BCR (ICC = .97, 95% CI [.91, 1.000], p = 001). Significant correlations between BCR and pharyngeal constriction ratio and total pharyngeal transit time were reported (p < .05). Using binomial logistic regression modeling, we found BCR was predictive of penetration-aspiration in children, χ²(13) = 58.093, p < .001, 64.9%. Children with BCR of ≥ 0.1 were 4 times more likely to aspirate. Conclusion BCR is a reliable, clinically useful measure to quantify postswallow residue in children, which can be used to identify and treat children with swallow impairments, as well as to measure outcomes of intervention.

European white paper: oropharyngeal dysphagia in head and neck cancer

PURPOSE

To develop a European White Paper document on oropharyngeal dysphagia (OD) in head and neck cancer (HNC). There are wide variations in the management of OD associated with HNC across Europe.

METHODS

Experts in the management of specific aspects of OD in HNC across Europe were delegated by their professional medical and multidisciplinary societies to contribute to this document. Evidence is based on systematic reviews, consensus-based position statements, and expert opinion.

RESULTS

Twenty-four sections on HNC-specific OD topics.

CONCLUSION

This European White Paper summarizes current best practice on management of OD in HNC, providing recommendations to support patients and health professionals. The body of literature and its level of evidence on diagnostics and treatment for OD in HNC remain poor. This is in the context of an expected increase in the prevalence of OD due to HNC in the near future. Contributing factors to increased prevalence include aging of our European population (including HNC patients) and an increase in human papillomavirus (HPV) related cancer, despite the introduction of HPV vaccination in various countries. We recommend timely implementation of OD screening in HNC patients while emphasizing the need for robust scientific research on the treatment of OD in HNC. Meanwhile, its management remains a challenge for European professional associations and policymakers.

Modulation of pharyngeal swallowing by bolus volume and viscosity

Oropharyngeal swallowing involves complex neuromodulation to accommodate changing bolus characteristics. The pressure events during deglutitive pharyngeal reconfiguration and bolus flow can be assessed quantitatively using high-resolution pharyngeal manometry with impedance. An 8-French solid-state unidirectional catheter (32 pressure sensors, 16 impedance segments) was used to acquire triplicate swallows of 3 to 20 ml across three viscosity levels using a Standardized Bolus Medium (SBMkit) product (Trisco, Pty. Ltd., Australia). An online platform (https://swallowgateway.com/; Flinders University, South Australia) was used to semiautomate swallow analysis. Fifty healthy adults (29 females, 21 males; mean age 46 yr; age range 19-78 yr old) were studied. Hypopharyngeal intrabolus pressure, upper esophageal sphincter (UES) maximum admittance, UES relaxation pressure, and UES relaxation time revealed the most significant modulation effects to bolus volume and viscosity. Pharyngeal contractility and UES postswallow pressures elevated as bolus volumes increased. Bolus viscosity augmented UES preopening pressure only. We describe the swallow modulatory effects with quantitative methods in line with a core outcome set of metrics and a unified analysis system for broad reference that contributes to diagnostic frameworks for oropharyngeal dysphagia.NEW & NOTEWORTHY The neuromodulation of the healthy oropharyngeal swallow response was described in relation to bolus volume and viscosity challenges, using intraluminal pressure and impedance topography methods. Among a wide range of physiological measures, those indicative of distension pressure, luminal opening, and flow timing were most significantly altered by bolus condition, and therefore can be considered to be potential markers of swallow neuromodulation. The study methods and associated findings inform a diagnostic framework for swallow assessment in patients with oropharyngeal dysphagia.

The use of impedance planimetry (Endoscopic Functional Lumen Imaging Probe, EndoFLIP® ) in the gastrointestinal tract: A systematic review

BACKGROUND AND PURPOSE

The EndoFLIP® system is a method of delineating impedance and was first designed to investigate the characteristics of the esophago-gastric junction. In the last decade, its use was widened to investigate other sphincteric and non-sphincteric systems of the gastrointestinal tract. The objective of the present systematic review was to summarize the available data in literature on the use of the EndoFLIP® system in the gastrointestinal tract, including sphincteric and non-sphincteric regions. We performed a systematic review in accordance with recommendations for systematic review using PRISMA guidelines without date restriction, until June 2020, using MEDLINE-PubMed, Cochrane Library, and Google Scholar databases. Only articles written in English were included in the present review. Five hundred and six unique citations were identified from all database combined. Of those, 95 met the inclusion criteria. There was a lack of standardization among studies in terms of anesthetic drugs use, probe placement, and inflation protocol. In most cases, only small cohorts of patients were included. Most studies investigated the EGJ, with a potential use of the EndoFLIP® to identify a subgroup of patients with achalasia and for intraoperative assessment of treatment efficacy in achalasia. However, the use of EndoFLIP® in the esophageal body (esophageal panometry), other esophageal diseases (gastro-esophageal reflux disease, eosinophilic esophagitis), and other sphincter regions (anal canal, pylorus) will need further confirmatory studies. The EndoFLIP® system provides detailed geometric data of the gastrointestinal lumen but further works are needed to determine its use in clinical practice.

A Systematic Review of the Physiological Effects of the Effortful Swallow Maneuver in Adults With Normal and Disordered Swallowing

Purpose This systematic review summarizes the biomechanical and functional effects of the effortful swallow in adults with and without dysphagia, highlighting clinical implications and future research needs. Specifically, the effects of the effortful swallow on swallowing physiology, safety, and efficiency were identified, as well as the strengths and limitations of current research. Method Recommendations specified by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses were followed. A literature search of three databases and relevant articles cited in the searched studies was performed. Two evaluators independently analyzed the studies for eligibility criteria, and final inclusion of studies was decided by consensus. Evaluators also assessed each study for quality of evidence. Results Twenty-three studies were included in this systematic review. Main findings indicated that the effortful swallow generated greater pressures in the tongue-to-palate, pharynx, upper esophageal sphincter, and esophageal regions. Inconsistent results for hyolaryngeal excursion were reported, as well as for swallowing function. Instructions of the effortful swallow varied greatly across studies. Two of the 23 studies were judged to be of high quality, and the remaining studies were of medium quality based on the quality indicators of this review. Conclusions Biomechanical effects of the effortful swallow included increased pressures in the oral, pharyngeal, and esophageal regions. Future investigations should address the effects of the effortful swallow in individuals with dysphagia and its potential role as a rehabilitative maneuver. Moreover, standardization of the effortful swallow instructions based on its physiological and functional effects is essential.

Research-based Updates in Swallowing and Communication Dysfunction in Parkinson Disease: Implications for Evaluation and Management

PURPOSE

Individuals with Parkinson disease (PD) present with complex and variable symptoms, with recent findings suggesting that the etiology of PD extends beyond the involvement of just the basal ganglia. These symptoms include significant impairments in the speech and swallowing domains, which can greatly affect quality of life and therefore require therapeutic attention. This research-based update reviews the neurophysiological basis for swallowing and speech changes in PD, the effectiveness of various types of treatments, and implications for symptom evaluation and management.

CONCLUSION

The mechanisms responsible for swallowing and speech symptoms in PD remain largely unknown. Dopaminergic medication and deep-brain-stimulation do not provide consistent benefits for these symptoms suggesting a non-dopaminergic network is involved. Importantly, evidence suggests that symptoms of dysphagia and hypokinetic dysarthria may be early indications of PD, so it is critical to investigate the cause of these changes.

Recent advances in dysphagia management

The literal definition of dysphagia is "disturbed eating". However, it is more accurately described in clinical practice as a sensation of food or liquid being stuck in the esophagus or chest. If this sensation is associated with pain, it is labeled odynophagia, and if it is associated with persistent obstruction and bolus retention, it is categorized as a food impaction. Through research and technological advances, we continue to expand our understanding of the etiologies and underlying pathophysiology relating to this complaint. However, for now, our clinical algorithms focus on endoscopy and manometry to break down dysphagia into three categories: obstructive dysphagia, esophageal motility disorders, and functional dysphagia. Here, we review some critical pitfalls in our current clinical diagnoses, new proposed underlying mechanisms of esophageal motor disorders, and developing technologies to aid in diagnosis and treatment.

Characterization of Esophageal Motility in Infants With Congenital Diaphragmatic Hernia Using High-resolution Manometry

OBJECTIVES

The aim of the study was to characterize esophageal motility and esophagogastric junction (EGJ) function in infants who underwent repair of an isolated congenital diaphragmatic hernia (iCDH).

METHODS

High-resolution manometry with impedance was used to investigate esophageal motility and EGJ function after diaphragmatic repair in 12 infants with iCDH (11 left-sided; 9 patch repair). They had esophageal motility studies during neonatal admission (n = 12), at 6 months (n = 10) and at 12 months of life (n = 7). Swallows were analyzed using conventional esophageal pressure topography and pressure flow analysis and were compared with 11 healthy preterm born infants at near-term age.

RESULTS

Esophageal peristaltic motor patterns in patients with iCDH were comparable to controls. EGJ end-expiratory pressure was higher in patients with patch repair compared with controls (P = 0.050) and those without patch (P = 0.009). The difference between inspiratory and expiratory pressures at the EGJ was lower in patients with iCDH with patch (P = 0.045) compared to patients without. Patients with iCDH with patch showed increased Pressure Flow Index, resistance of bolus flow at the EGJ, compared with controls (P = 0.043).

CONCLUSIONS

Normal esophageal wave patterns are present in the investigated patients with iCDH. EGJ end-expiratory pressure seems lower in patients with iCDH without patch suggesting a decreased EGJ barrier function hence increased vulnerability to gastroesophageal reflux. Patch repair appears to increase end-expiratory pressure at the EGJ above that of controls suggesting that patch surgery tightens the EGJ, thereby increasing flow resistance. This is in line with the increased Pressure Flow Index. In infants with a patch, the inspiration-expiration pressure difference is lower, reflecting diminished activity of the crural diaphragm.

High-Resolution Pharyngeal Manometry and Impedance: Protocols and Metrics-Recommendations of a High-Resolution Pharyngeal Manometry International Working Group

High-resolution manometry has traditionally been utilized in gastroenterology diagnostic clinical and research applications. Recently, it is also finding new and important applications in speech pathology and laryngology practices. A High-Resolution Pharyngeal Manometry International Working Group was formed as a grass roots effort to establish a consensus on methodology, protocol, and outcome metrics for high-resolution pharyngeal manometry (HRPM) with consideration of impedance as an adjunct modality. The Working Group undertook three tasks (1) survey what experts were currently doing in their clinical and/or research practice; (2) perform a review of the literature underpinning the value of particular HRPM metrics for understanding swallowing physiology and pathophysiology; and (3) establish a core outcomes set of HRPM metrics via a Delphi consensus process. Expert survey results were used to create a recommended HRPM protocol addressing system configuration, catheter insertion, and bolus administration. Ninety two articles were included in the final literature review resulting in categorization of 22 HRPM-impedance metrics into three classes: pharyngeal lumen occlusive pressures, hypopharyngeal intrabolus pressures, and upper esophageal sphincter (UES) function. A stable Delphi consensus was achieved for 8 HRPM-Impedance metrics: pharyngeal contractile integral (CI), velopharyngeal CI, hypopharyngeal CI, hypopharyngeal pressure at nadir impedance, UES integrated relaxation pressure, relaxation time, and maximum admittance. While some important unanswered questions remain, our work represents the first step in standardization of high-resolution pharyngeal manometry acquisition, measurement, and reporting. This could potentially inform future proposals for an HRPM-based classification system specifically for pharyngeal swallowing disorders.

The Association of 3-D Volume and 2-D Area of Post-swallow Pharyngeal Residue on CT Imaging

Pharyngeal residue, the material that remains in the pharynx after swallowing, is an important marker of impairments in swallowing and prandial aspiration risk. The goals of this study were to determine whether the 2D area of post-swallow residue accurately represents its 3D volume, and if the laterality of residue would affect this association. Thirteen patients with dysphagia due to brainstem stroke completed dynamic 320-detector row computed tomography while swallowing a trial of 10 ml honey-thick barium. 3D volumes of pharyngeal residue were compared to 2D lateral and anterior-posterior areas, and a laterality index for residue location was computed. Although the anteroposterior area of residue was larger than the lateral area, the two measures were positively correlated with one another and with residue volume. On separate bivariate regression analyses, residue volume was accurately predicted by both lateral (R² = 0.91) and anteroposterior (R² = 0.88) residue areas, with limited incidence of high residuals. Half of the sample demonstrated a majority of pharyngeal residue lateralized to one side of the pharynx, with no effect of laterality on the association between areas and volume. In conclusion, the area of post-swallow pharyngeal residue was associated with volume, with limitations in specific cases. Direct measurement of pharyngeal residue volume and swallowing physiology with 3D-CT can be used to validate results from standard 2D instrumentation.

Derivation and measurement consistency of a novel biofluid dynamics measure of deglutitive bolus-driving function-pharyngeal swallowing power

BACKGROUND

The primary function of the pharyngeal swallowing mechanism is to drive ingested materials into the esophagus. Currently, a definitive measure of pharyngeal bolus-driving function that accounts for bolus movement remains lacking. The primary objectives of this study were to describe the derivation of a novel biofluid dynamics measure of deglutition-that is, pharyngeal swallowing power (PSP)-and to demonstrate the consistency of PSP in normal swallowing.

METHODS

The pharyngeal swallowing mechanism was conceptualized as a hydraulic power system with the upper esophageal sphincter (UES) as a conduit. PSP was calculated as the product of bolus pressure and flow across the UES. Thirty-four young healthy subjects swallowed materials consisting of two bolus volumes (10, 20 mL) and four bolus viscosities (thin liquid, nectar-thick liquid, honey-thick liquid, pudding). High-resolution impedance manometry was used for data collection. The consistency of PSP across specific bolus conditions was evaluated using standardized Cronbach's coefficient alpha.

KEY RESULTS

Standardized Cronbach's coefficient alphas in specific bolus conditions ranged between 0.85 and 0.93. Fisher weighted mean Cronbach's coefficient alphas for swallow trials across bolus volumes and across bolus viscosities ranged from 0.86 to 0.90. Fisher weighted mean Cronbach's coefficient alpha for overall consistency of PSP across all swallow trials was 0.88.

CONCLUSIONS AND INFERENCES

PSP estimates the output power of the pharyngeal bolus-driving mechanism during deglutition. PSP's high consistency indicates that it can be a useful biofluid dynamics measure of pharyngeal bolus-driving function. Current results also demonstrate that consistency in pharyngeal bolus propulsion is an important physiological target for the pharyngeal swallowing mechanism.

Swall-E: A robotic in-vitro simulation of human swallowing

Swallowing is a complex physiological function that can be studied through medical imagery techniques such as videofluoroscopy (VFS), dynamic magnetic resonance imagery (MRI) and fiberoptic endoscopic evaluation of swallowing (FEES). VFS is the gold standard although it exposes the subjects to radiations. In-vitro modeling of human swallowing has been conducted with limited results so far. Some experiments were reported on robotic reproduction of oral and esophageal phases of swallowing, but high fidelity reproduction of pharyngeal phase of swallowing has not been reported yet. To that end, we designed and developed a robotic simulator of the pharyngeal phase of human swallowing named Swall-E. 17 actuators integrated in the robot enable the mimicking of important physiological mechanisms occurring during the pharyngeal swallowing, such as the vocal fold closure, laryngeal elevation or epiglottis tilt. Moreover, the associated computer interface allows a control of the actuation of these mechanisms at a spatio-temporal accuracy of 0.025 mm and 20 ms. In this study preliminary experiments of normal pharyngeal swallowing simulated on Swall-E are presented. These experiments show that a 10 ml thick bolus can be swallowed by the robot in less than 1 s without any aspiration of bolus material into the synthetic anatomical laryngo-tracheal conduit.

Bolus volume and viscosity effects on pharyngeal swallowing power-How physiological bolus accommodation affects bolus dynamics

BACKGROUND

Pharyngeal swallowing power (PSP) is a novel measure of pharyngeal bolus-driving function derived from fluid dynamics principles. This study examined the impact of bolus volume and viscosity on PSP to determine bolus effects on pharyngeal bolus dynamics. The impact of bolus accommodation and physical characteristics of boluses were also explored.

METHODS

Thirty-four healthy subjects swallowed materials consisting of two bolus volumes (10 and 20 mL) and four bolus viscosities (thin liquid, nectar-thick liquid, honey-thick liquid and pudding). High-resolution impedance manometry was used for data collection. The pharyngeal swallowing mechanism was conceptualized as a hydraulic power system with the UES as a conduit, and PSP was calculated as the product of bolus pressure and flow across the UES. The impact of bolus characteristics on PSP was evaluated using a mixed model approach.

KEY RESULTS

Both bolus volume (F_1,32.8  = 412.73, P < 0.0001) and viscosity (F_3,84.7  = 28.94, P < 0.0001) were significant predictors of PSP. PSP for 20 mL bolus volume was greater than for 10 mL bolus volume. PSP was lowest in the thin liquid bolus condition and highest in the pudding bolus. All pairwise comparisons among bolus viscosities were significant except between thin liquid and nectar-thick liquid bolus viscosities. Test of linear trend across bolus viscosities was significant (F_1,97.2  = 77.25, P < 0.0001).

CONCLUSIONS & INFERENCES

Pharyngeal swallowing power variation across bolus conditions illustrates bolus-related changes in bolus dynamics. Bolus effects on PSP likely result from physiological bolus accommodation combined with physical characteristics of boluses.

Effects of cortical anodal transcranial direct current stimulation on swallowing biomechanics

BACKGROUND

Anodal transcranial direct current stimulation (tDCS) has demonstrated effects on corticobulbar excitability and swallowing function as assessed via clinical rating scales in stroke cohorts. Biomechanical effects of anodal tDCS on swallowing remain largely unexplored. We investigated how anodal tDCS applied over the floor of mouth (FOM) representation on the primary motor cortex affects swallowing biomechanics in healthy participants.

METHODS

Anodal and sham tDCS were applied for 20 minutes at 1.5 mA. Corticobulbar excitability was assessed using motor evoked potentials at baseline and 0, 15, 30 and 45 minutes post-tDCS, as assessed by transcranial magnetic stimulation. Swallowing function was assessed pre- and post-tDCS using routine clinical assessments (Study 1) and pharyngeal high resolution impedance manometry (Study 2).

KEY RESULTS

Study 1 (n = 17) showed increased corticobulbar excitability and performance on a skilled swallowing task following anodal wetDCS, but not sham tDCS. In Study 2 (n = 10) anodal tDCS resulted in increased bolus admittance across the upper esophageal sphincter, but decreased pharyngeal and upper esophageal contractile vigor.

CONCLUSIONS

Clinical improvements of dietary intake are likely driven by swallowing neuroplastic reorganization which improves bolus admittance across the upper esophageal sphincter (UES).

INFERENCES

The documented changes make motor cortical application of anodal tDCS a promising adjunct to swallowing rehabilitation practice.

The critical importance of pharyngeal contractile forces on the validity of intrabolus pressure as a predictor of impaired pharyngo-esophageal junction compliance

INTRODUCTION

Restrictive defects of the pharyngo-esophageal junction (PEJ) are common in both structural and neurological disorders and are amenable to therapies aiming to reduce outflow resistance. Intrabolus pressure (IBP) acquired with high-resolution manometry and impedance (HRMI) is an indicator of resistance and a marker of reduced PEJ compliance. Constraints and limitations of IBP as well as the optimal IBP parameter remain undefined.

AIMS

To determine: (i) the impact of peak pharyngeal pressure (PeakP) on the diagnostic accuracy of IBP for the detection of a restrictive defect at the PEJ and (ii) the optimal IBP parameter for this purpose.

METHODS

In 52 dysphagic patients previously treated for head and neck cancer. Five candidate IBP measures and PeakP were obtained with HRMI, as well as a presence of a stricture determined by a mucosal tear after endoscopic dilatation. Predictive values of IBP measures were evaluated by receiver operating characteristic (ROC) analysis for all patients and reiterated as patients with lowest PeakP were progressively removed from the cohort.

RESULTS

All IBP parameters had fair to good accuracy at predicting strictures. Intrabolus pressure measured at a discrete point of maximum admittance 1 cm above the maximal excursion of the upper esophageal sphincter had highest sensitivity (0.76) and specificity (0.78). When PeakP was at least 57 mm Hg both sensitivity and specificity improved to 0.9.

CONCLUSIONS

Pharyngeal propulsive force has substantial impact on the accuracy of IBP as a predictor of a PEJ stricture. When PeakP is ≥57 mm Hg, an elevated IBP is highly predictive of a restrictive defect at the PEJ.

Correlates of Early Pharyngeal High-Resolution Manometry Adoption in Expert Speech-Language Pathologists

Pharyngeal high-resolution manometry (HRM) is at a point of entry into speech-language pathologist (SLP) clinical practice. However, the demographic characteristics of SLPs who are early adopters of HRM are unclear; perspectives of early adopters may shape how the technology is received by the field at large. We hypothesized that younger SLPs, those working in outpatient settings, those with a strong knowledge base in HRM, and those with experience in other types of instrumentation are more likely to have interest in adopting HRM. We surveyed the population of board-certified SLPs (BCS-S; n = 262) with a 33% response rate (n = 78). Firth logistic regression was used to determine differences in those expressing interest in adopting HRM into future practice (n = 28) and those who did not (n = 45) from the analytic sample of 73 respondents. The best fitting model predicted that SLPs: (1) with training in more types of instrumentation; and (2) believing they could explain the HRM procedure to a patient were more likely to plan to adopt pharyngeal HRM into regular clinical practice. Experience with a variety of instrumentation techniques may encourage SLPs to use new forms of technology. Knowledge of early adopter demographics will allow for development of targeted trainings and determination of HRM implementation barriers. Identification of a clinician sub-group more likely to adopt other new technologies in the future may also be possible.

Effects of remifentanil on pharyngeal swallowing: A double blind randomised cross-over study in healthy volunteers

BACKGROUND

Exposure to remifentanil increases the incidence of pulmonary aspiration in healthy volunteers. This effect may be explained by impairment of airway defence mechanisms and/or altered swallowing function. Pressure-flow analysis is a technique that allows objective assessment of swallowing based on pressure-impedance patterns recorded during bolus swallowing.

OBJECTIVES

The aim of this study was to use pressure-flow analysis to quantify the effect of remifentanil on healthy pharyngeal swallowing and to compare these effects with morphine.

DESIGN

A double-blind, randomised, cross-over study.

SETTING

A tertiary care teaching hospital.

VOLUNTEERS

Eleven young volunteers (mean age, 23 years) and seven older volunteers (mean age, 73 years).

INTERVENTIONS

Volunteers were studied twice and received either a target-controlled remifentanil infusion (target concentrations: young, 3 ng ml; old, 2 ng ml) or a bolus injection of morphine (dose: young, 0.1 mg kg; old, 0.07 mg kg). Pharyngeal pressure and impedance were recorded with an indwelling catheter while swallowing 10 boluses of liquid during each measuring phase. Variables defining swallowing function were calculated and compared to determine drug effects.

MAIN OUTCOME MEASURES

Pharyngeal pressure-flow variables following remifentanil exposure.

RESULTS

Changes produced by remifentanil in the measured variables were consistent with greater dysfunction of swallowing. Both the strength of the pharyngeal contractions and pharyngeal bolus propulsion were reduced, whereas flow resistance was increased. The swallow risk index, a global index of swallowing dysfunction, increased overall. At the experimental doses tested, morphine produced similar, but less extensive effects on swallowing.

CONCLUSION

Remifentanil induced dysfunction of the pharyngeal swallowing mechanism. This may contribute to an increased risk of aspiration.

TRIAL REGISTRATION

NCT01924234 (www.clinicaltrials.gov).

Involvement of hypoglossal and recurrent laryngeal nerves on swallowing pressure

Swallowing pressure generation is important to ensure safe transport of an ingested bolus without aspiration or leaving residue in the pharynx. To clarify the mechanism, we measured swallowing pressure at the oropharynx (OP), upper esophageal sphincter (UES), and cervical esophagus (CE) using a specially designed manometric catheter in anesthetized rats. A swallow, evoked by punctate mechanical stimulation to the larynx, was identified by recording activation of the suprahyoid and thyrohyoid muscles using electromyography (EMG). Areas under the curve of the swallowing pressure at the OP, UES, and CE from two trials indicated high intrasubject reproducibility. Effects of transecting the hypoglossal nerve (12N) and recurrent laryngeal nerve (RLN) on swallowing were investigated. Following bilateral hypoglossal nerve transection (Bi-12Nx), OP pressure was significantly decreased, and time intervals between peaks of thyrohyoid EMG bursts and OP pressure were significantly shorter. Decreased OP pressure and shortened times between peaks of thyrohyoid EMG bursts and OP pressure following Bi-12Nx were significantly increased and longer, respectively, after covering the hard and soft palates with acrylic material. UES pressure was significantly decreased after bilateral RLN transection compared with that before transection. These results suggest that the 12N and RLN play crucial roles in OP and UES pressure during swallowing, respectively. We speculate that covering the palates with a palatal augmentation prosthesis may reverse the reduced swallowing pressure in patients with 12N or tongue damage by the changes of the sensory information and of the contact between the tongue and a palates. NEW & NOTEWORTHY Hypoglossal nerve transection reduced swallowing pressure at the oropharynx. Covering the hard and soft palates with acrylic material may reverse the reduced swallowing function caused by hypoglossal nerve damage. Recurrent laryngeal nerve transection reduced upper esophageal sphincter negative pressure during swallowing.

Characterization of pharyngeal peristaltic pressure variability during volitional swallowing in healthy individuals

BACKGROUND

Recent technological advances incorporated in high resolution manometry have justifiably heightened interest in manometric evaluation of the pharynx. Despite this interest, from both physiologic and clinical perspective there remain a number of unanswered questions regarding the magnitude of variability of pharyngeal pressure phenomena. Therefore, the aim of the present study was to characterize in healthy individuals the inter-subject and recording-site specific variability of pharyngeal peristaltic pressure phenomena.

METHODS

We studied 32 healthy subjects (age: 21-83 years,20 under 35 years) during dry,5 and 10 mL water swallows ×3. Pharyngeal peristaltic pressures were recorded using a high resolution (HR) manometric system and a catheter assembly with 36 circumferential sensors spaced at 1 cm intervals positioned trans-nasally to traverse the pharynx, UES and proximal esophagus.

KEY RESULTS

Both site-specific pressure data and the Pharyngeal contractile integral (PhCI) showed wide dispersion ranging between values under 50 mm Hg to over 300 mm Hg and 100-600 mm Hg/cm/s,respectively. There was also wide range of dispersion of data for both the standard deviations and the coefficient of variation for all sites (P=.001). The coefficient of variation for PhCI ranged between 0.02 and 0.25 representing data dispersion of 2-25 percent of the mean among subjects (P=.001). Position, age and volume of swallowed fluid did not influence the magnitude of variability.

CONCLUSIONS

Deglutitive Pharyngeal peristalsis generates pressures with significant degree of site-related and inter-subject variability. This variability is not influenced by age, position and volume of swallowed fluid.

Biomechanical Quantification of Mendelsohn Maneuver and Effortful Swallowing on Pharyngoesophageal Function

Objective

To quantify the effects of 2 swallowing maneuvers used in dysphagia rehabilitation—the Mendelsohn maneuver and effortful swallowing—on pharyngoesophageal function with novel, objective pressure-flow analysis.

Study Design

Evaluation of intervention effects in a healthy control cohort.

Setting

A pharyngoesophageal motility research laboratory in a tertiary education facility.

Subjects

Twelve young healthy subjects (9 women, 28.6 ± 7.9 years) from the general public, without swallowing impairment, volunteered to participate in this study.

Methods

Surface electromyography from the floor-of-mouth musculature and high-resolution impedance manometry–based pressure flow analysis were used to assess floor-of-mouth activation and pharyngoesophageal motility, respectively. Subjects each performed 10 noneffortful control swallows, Mendelsohn maneuver swallows, and effortful swallows, with a 5-mL viscous bolus. Repeated measures analyses of variance was used to compare outcome measures across conditions.

Results

Effortful and Mendelsohn swallows generated greater floor-of-mouth contraction ( P = .001) and pharyngeal pressure ( P < .0001) when compared with control swallows. There were no changes at the level of the upper esophageal sphincter, except for a faster opening to maximal diameter during maneuver swallows ( P = .01). The proximal esophageal contractile integral was reduced during Mendelsohn swallows ( P = .001).

Conclusion

Effortful and Mendelsohn maneuver swallows significantly alter the pharyngoesophageal pressure profile. Faster opening of the upper esophageal sphincter may facilitate bolus transfer during maneuver swallows; however, reduced proximal esophageal contractility during Mendelsohn maneuver swallows may impair bolus flow and aggravate dysphagic symptoms.

Pharyngeal peristaltic pressure variability, operational range, and functional reserve

The present understanding of pharyngeal motor function remains incomplete. Among the remaining gaps of knowledge in this regard is the magnitude of variability of pharyngeal peristaltic pressure amplitude. Although variability can pose difficulty in interpretation of manometric findings, its magnitude can inform the operational range and reserve of the pharyngeal contractile function. We aimed to define the intra- and intersubject and intersession variability of select pharyngeal manometric parameters and, using this information, determine the number of swallow repetitions for acquiring reliable pharyngeal manometric data. We recorded pharyngeal peristalsis in 10 healthy subjects (age: 50 ± 25 yr, 5 women) by high-resolution manometry during two separate sessions of 20 sequences of 0.5-ml water swallows. Two-way ANOVA showed significant variation in the mean peak peristaltic pressure value across sites (P < 0.0001) as well as within the data at each site (P < 0.0001). Similarly, the pharyngeal contractile integral exhibited significant inter- (P = 0.003) and intrasubject (P < 0.001) variability. The Shapiro-Wilk normality test showed mixed results, in that some sites showed normally distributed data, whereas others did not. A robust Monte Carlo simulation showed that the nominal sample size was different for various tested metrics. For a power of 0.8, commonly accepted as an adequate threshold for acceptable statistical power, the optimal sample size for various peristaltic parameters ranged between 3 and 15. There is significant intra- and intersubject variability in site-specific and integrated parameters of pharyngeal peristalsis. The observed variance indicates a significant operational range and reserve in pharyngeal contractile function while necessitating parameter-specific sample size for reliable results.NEW & NOTEWORTHY Intra- and intersubject variability are significant and different at various sites within the contractile pharynx. In addition, significant swallow-to-swallow and subject-to-subject variability exists in pharyngeal contractile integral. The range of intrasubject variability indicates the existence of broad operational range and reserve. Lastly, our variability studies informed Monte Carlo and power analyses, yielding estimates of sample size that would ensure accurate representation of pressure metric variability.

Advances with Neonatal Aerodigestive Science in the Pursuit of Safe Swallowing in Infants: Invited Review

Feeding, swallowing, and airway protection are three distinct entities. Feeding involves a process of sequential, neurosensory, and neuromotor interactions of reflexes and behaviors facilitating ingestion. Swallowing involves anterograde bolus movement during oral-, pharyngeal-, and esophageal phases of peristalsis into stomach. During these events, coordination with airway protection is vital for homeostasis in clearing any material away from airway vicinity. Neurological-airway-digestive inter-relationships are critical to the continuum of successful feeding patterns during infancy, either in health or disease. Neonatal feeding difficulties encompass a heterogeneous group of neurological, pulmonary, and aerodigestive disorders that present with multiple signs posing as clinical conundrums. Significant research breakthroughs permitted understanding of vagal neural pathways and functional aerodigestive connectivity involved in regulating swallowing and aerodigestive functions either directly or indirectly by influencing the supra-nuclear regulatory centers and peripheral effector organs. These neurosensory and neuromotor pathways are influenced by pathologies during perinatal events, prematurity, inflammatory states, and coexisting medical and surgical conditions. Approaches to clarify pathophysiologic mapping of aerodigestive interactions, as well as translating these discoveries into the development of personalized and simplified feeding strategies to advance child health are discussed in this review article.

The Potential Benefits of Applying Recent Advances in Esophageal Motility Testing in Patients with Esophageal Atresia

Infants and children with esophageal atresia commonly present with swallowing dysfunction or dysphagia. Dysphagia can lead to a range of significant consequences such as aspiration pneumonia, malnutrition, dehydration, and food impaction. To improve oral intake, the clinical diagnosis of dysphagia in patients with esophageal atresia should focus on both the pharynx and the esophagus. To characterize the complex interactions of bolus flow and motor function between mouth, pharynx, and esophagus, a detailed understanding of normal and abnormal deglutition is required through the use of adequate and objective assessment techniques. As clinical symptoms do not correlate well with conventional assessment methods of motor function such as radiology or manometry but do correlate with bolus flow, the current state-of-the-art diagnosis involves high-resolution manometry combined with impedance measurements to characterize the interplay between esophageal motor function and bolus clearance. Using a novel pressure flow analysis (PFA) method as an integrated analysis method of manometric and impedance measurements, differentiation of patients with impaired esophago-gastric junction relaxation from patients with bolus outflow disorders is clinically relevant. In this, pressure flow matrix categorizing the quantitative PFA measures may be used to make rational therapeutic decisions in patients with esophageal atresia. Through more advanced diagnostics, improved understanding of pathophysiology may improve our patient care by directly targeting the failed biomechanics of both the pharynx and the esophagus.

Chicago Classification of Esophageal Motility Disorders: Applications and Limits in Adults and Pediatric Patients with Esophageal Symptoms

The Chicago classification (CC) is most valued for its systematic approach to esophageal disorders and great impact in unifying practice for esophageal manometric studies. In view of the ever-growing wealth of knowledge and experience gained by the expanding use of high-resolution manometry (HRM) in various clinical scenarios, the CC is regularly updated. Its clinical impact and ability to predict clinical outcome, both in adults and pediatrics, will be further promoted by recognizing its current limitations, incorporating new metrics in its diagnostic algorithms and adjusting the HRM protocols based on the clinical question posed. Herein, we discuss the current limitations of the CC and highlight some areas of improvement for the future.

Pressure-Flow Analysis for the Assessment of Pediatric Oropharyngeal Dysphagia

OBJECTIVES

To determine which objective pressure-impedance measures of pharyngeal swallowing function correlated with clinically assessed severity of oropharyngeal dysphagia (OPD) symptoms.

STUDY DESIGN

Forty-five children with OPD and 34 control children without OPD were recruited and up to 5 liquid bolus swallows were recorded with a solid-state high-resolution manometry with impedance catheter. Individual measures of pharyngeal and upper esophageal sphincter (UES) function and a swallow risk index composite score were derived for each swallow, and averaged data for patients with OPD were compared with those of control children without OPD. Clinical severity of OPD symptoms and oral feeding competency was based on the validated Dysphagia Disorders Survey and Functional Oral Intake Scale.

RESULTS

Those objective measures that were markers of UES relaxation, UES opening, and pharyngeal flow resistance differentiated patients with and without OPD symptoms. Patients demonstrating abnormally high pharyngeal intrabolus pressures and high UES resistance, markers of outflow obstruction, were most likely to have signs and symptoms of overt Dysphagia Disorders Survey (OR 9.24, P = .05, and 9.7, P = .016, respectively).

CONCLUSION

Pharyngeal motor patterns can be recorded in children by the use of HRIM and pharyngeal function can be defined objectively with the use of pressure-impedance measures. Objective measurements suggest that pharyngeal dysfunction is common in children with clinical signs of OPD. A key finding of this study was evidence of markers of restricted UES opening.

Dynamic Imaging Grade of Swallowing Toxicity (DIGEST): Scale development and validation

BACKGROUND

The National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE) is the universal framework for toxicity reporting in oncology trials. The objective of this study was to develop a CTCAE-compatible modified barium swallow (MBS) grade for the purpose of grading pharyngeal dysphagia as a toxicity endpoint in cooperative-group organ-preservation trials for head and neck cancer (HNC). It was hypothesized that a 5-point, CTCAE-compatible MBS grade (Dynamic Imaging Grade of Swallowing Toxicity [DIGEST]) based on the interaction of pharyngeal residue and laryngeal penetration/aspiration ratings would be feasible and psychometrically sound.

METHODS

A modified Delphi exercise was conducted for content validation, expert consensus, and operationalization of DIGEST criteria. Two blinded raters scored 100 MBSs conducted before or after surgical or nonsurgical organ preservation. Intrarater and interrater reliability was tested with weighted κ values. Criterion validity against oropharyngeal swallow efficiency (OPSE), the Modified Barium Swallow Impairment Profile (MBSImP™©), the MD Anderson Dysphagia Inventory (MDADI), and the Performance Status Scale for Head and Neck Cancer Patients (PSS-HN) was assessed with a 1-way analysis of variance and post hoc pairwise comparisons between DIGEST grades.

RESULTS

Intrarater reliability was excellent (weighted κ = 0.82-0.84) with substantial to almost perfect agreement between raters (weighted κ = 0.67-0.81). DIGEST significantly discriminated levels of pharyngeal pathophysiology (MBSImP™©: r = 0.77; P < .0001), swallow efficiency (OPSE: r = -0.56; P < .0001), perceived dysphagia (MDADI: r = -0.41; P < .0001), and oral intake (PSS-HN diet: r = -0.49; P < .0001).

CONCLUSIONS

With the development of DIGEST, the MBS rating has been adapted to the CTCAE nomenclature of ordinal toxicity grading used in oncology trials. DIGEST offers a psychometrically sound measure for HNC clinical trials and investigations of toxicity profiles, dose responses, and predictive modeling. Cancer 2017;62-70. © 2016 American Cancer Society.

Modulation of Upper Esophageal Sphincter (UES) Relaxation and Opening During Volume Swallowing

UES opening occurs following cricopharyngeus deactivation and submental muscle contraction causing hyolaryngeal elevation and UES distraction. During impedance manometry, the inverse of impedance (admittance) can be used to measure bolus presence and infer UES opening. We hypothesized that the temporal relationship between UES relaxation, opening and hyolaryngeal elevation would change with increasing bolus volume. Simultaneous intramuscular cricopharyngeal (CP) electromyography (EMG), surface submental EMG (SM-EMG), and high-resolution impedance manometry were recorded in eight (aged 27 ± 7 years, 5 M) healthy volunteers, while swallowing 0.9 % saline boluses of 2, 5, 10, and 20 ml. Data were exported and analyzed via Matlab. Statistical analysis comprised repeated measures one-way ANOVA and Pearson correlation. A P value of <0.05 was considered significant. Duration of CP deactivation increased at 20 ml volume (P < 0.001). UES relaxation and opening increased with increasing bolus volume (P < 0.001); however, overall duration of SM activation did not change. As UES opening occurs progressively earlier with increasing volumes, peak SM-EMG activity occurs relatively later (P < 0.001) and shifts from occurring before to following peak UES distention. During healthy swallowing, there is sensory modulation of cricopharyngeal and submental muscle activity. Intrabolus pressures, transmitted from the tongue base and pharynx, play a progressively more important role in sphincter opening with increasing volume. The findings may explain why some healthy elderly and patients with oropharyngeal dysphagia have difficulty swallowing larger while tolerating smaller bolus volumes.

Videofluoroscopic Swallow Examination Does Not Accurately Detect Cricopharyngeal Radiation Strictures

Videofluoroscopy is the standard technique to evaluate dysphagia following radiotherapy for head and neck cancer (HNC). The accuracy of radiography in detecting strictures at the pharyngoesophageal junction is unknown. Our aim was to determine the diagnostic accuracy of videofluoroscopy in detecting strictures at the pharyngoesophageal junction prior to endoscopic dilatation in a consecutive series of HNC survivors with dysphagia. Presence of a stricture on videofluoroscopy was determined by 3 experienced blinded investigators and compared against a gold standard, defined as presence of a mucosal tear during endoscopic dilatation. In 10 of 33 patients, there was complete agreement among observers with respect to the presence or absence of a stricture. Overall, the concordance among observers in identification of strictures was very poor, with a kappa of 0.05 ( P = .30). The diagnostic sensitivity and specificity of videofluoroscopy in detecting strictures was 0.76 and 0.58, respectively. Videofluoroscopy alone is inadequate to detect strictures in HNC survivors with dysphagia.

Remifentanil alters sensory neuromodulation of swallowing in healthy volunteers: quantification by a novel pressure-impedance analysis

Exposure to remifentanil contributes to an increased risk of pulmonary aspiration, likely through reduced pharyngeal contractile vigor and diminished bolus propulsion during swallowing. We employed a novel high-resolution pressure-flow analysis to quantify the biomechanical changes across the upper esophageal sphincter (UES). Eleven healthy young (23.3 ± 3.1 yr old) participants (7 men and 4 women) received remifentanil via intravenous target-controlled infusion with an effect-site concentration of 3 ng/ml. Before and 30 min following commencement of remifentanil administration, participants performed ten 10-ml saline swallows while pharyngoesophageal manometry and electrical impedance data were recorded using a 4.2-mm-diameter catheter housing 36 circumferential pressure sensors. Remifentanil significantly shortened the duration of UES opening (P < 0.001) and increased residual UES pressure (P = 0.003). At the level of the hypopharynx, remifentanil significantly shortened the latency from maximum bolus distension to peak contraction (P = 0.004) and significantly increased intrabolus distension pressure (P = 0.024). Novel mechanical states analysis revealed that the latencies between the different phases of the stereotypical UES relaxation sequence were shortened by remifentanil. Reduced duration of bolus flow during shortened UES opening, in concert with increased hypopharyngeal distension pressures, is mechanically consistent with increased flow resistance due to a more rapid bolus flow rate. These biomechanical changes are congruent with modification of the physiological neuroregulatory mechanism governing accommodation to bolus volume.

Expanding Instrumental Options for Dysphagia Diagnosis and Research: Ultrasound and Manometry

Diagnostic assessment of swallowing in routine clinical practice relies heavily on the long-standing techniques of videofluoroscopic swallowing study (VFSS) and videoendoscopic evaluation of swallowing (VEES). These complementary and sophisticated techniques provide a real-time visualization of biomechanical movements of the structures involved in swallowing and consequent effects on bolus flow. Despite the sophistication of this instrumentation, interpretation relies heavily on subjective clinical judgement and temporal resolution is limited, limitations that may influence patient management. Adjunctive diagnostic assessments may be utilized to compensate for the limitations posed by VFSS and VEES. Ultrasound and pharyngeal manometry do not represent the latest in technological advances, with both emerging in swallowing research over 20 years ago. However, both have resisted integration into routine clinical practice, despite the fact that they offer quantitative metrics of swallowing that are not available using standard techniques. The aim of this review is to present recent research on these two less frequently used modalities in clinical swallowing assessment, discuss potential applications in clinical practice and review supportive data on test-retest reliability, rater reliability and validity. The paper will conclude with a case report that exemplifies the unique contribution of these modalities in executing and revising therapeutic approaches for a patient with neurogenic dysphagia.

Pressure topography metrics for high-resolution pharyngeal-esophageal manofluorography-a normative study of younger and older adults

BACKGROUND

We aimed to define normative values for novel pressure topography metrics for high-resolution pharyngeal-esophageal manofluorography. The effects of age, gender, and bolus properties were examined.

METHODS

Concurrent high-resolution manometry (HRM) and videofluoroscopy data were collected from 22 younger (aged 21-40) and 22 older (aged 60-80) healthy subjects. Pressure topography was analyzed by correlating pressure domains with videofluoroscopic events. Nine pressure topography metrics of the pharyngeal and proximal esophageal swallow were extracted; four of these were also compared with previously obtained esophageal HRM studies to assess the effects of catheter diameter.

KEY RESULTS

Older individuals exhibited more vigorous contractility in the pharynx than did younger subjects with all bolus types, but the greatest values for both groups were with effortful swallow and on that measure the age groups were similar. Upper esophageal sphincter (UES) intrabolus pressure during sphincter opening was also greater in the older subjects. Some gender differences were observed, particularly related to proximal esophageal contractile vigor. Bolus consistency had no consistent effect. Studies using the larger catheter diameter resulted in significantly greater contractile vigor in the UES and proximal esophagus.

CONCLUSIONS & INFERENCES

Older adults exhibited more vigorous pharyngeal contractions than young adults, albeit within a similar range of capacity, perhaps reflecting a compensatory response to other age-related physiological changes. Greater UES intrabolus pressures observed during bolus transit in the older group likely reflect reduced UES compliance with age. Normative data on novel HRM metrics collected in this study can serve as a reference for future clinical studies.

Biomechanics of Pharyngeal Deglutitive Function following Total Laryngectomy

OBJECTIVE

Postlaryngectomy, pharyngeal weakness, and pharyngoesophageal junction (PEJ) restriction are the candidate mechanisms of dysphagia. The aims were, in laryngectomees, whether (1) hypopharyngeal propulsion is reduced and/or PEJ resistance is increased, (2) dilatation improves dysphagia, and (3) whether symptomatic improvement correlates with reduced PEJ resistance.

DESIGN

Multidisciplinary cross-sectional study.

SETTING

Tertiary academic hospital.

SUBJECTS AND METHODS

Swallow biomechanics were assessed in 30 laryngectomees. Patients were stratified into severe dysphagia (Sydney Swallow Questionnaire >500) and mild/nil dysphagia (Sydney Swallow Questionnaire ≤500). Average hypopharyngeal peak (contractile) pressure (hPP) and hypopharyngeal intrabolus pressure (hIBP) were measured from high-resolution manometry with concurrent videofluoroscopy based on barium swallows (2.5 and 10 mL). In consecutive 5 patients, measurements were repeated after dilatation.

RESULTS

Dysphagia was reported by 87%, and 57% had severe and 43% had mild/nil dysphagia. hIBP increased with larger bolus volumes (P < .0001), while hPP stayed stable and PEJ diameter plateaued at 9 mm. Laryngectomees had lower hPP (110 ± 14 vs 170 ± 15 mm Hg; P = .0162) and higher hIBP (29 ± 5 vs 6 ± 5 mm Hg; P = .156) than controls. There were no differences in hPP between patient groups. However, hIBP was higher in severe than in mild/nil dysphagia (41 ± 10 vs 13 ± 3 mm Hg; P = .02). Predilation hIBP (R(2) = 0.97) and its decrement postdilatation (R(2) = 0.98) well predicted symptomatic improvement.

CONCLUSIONS

PEJ resistance correlates better with dysphagia severity than peak pharyngeal pressure and is more sensitive to bolus sizes than PEJ diameter. Both baseline PEJ resistance and its decrement following dilatation are strong predictors of treatment outcome. PEJ resistance is vital to detect, as it is reversible and can predict the response to dilatation regimens.

The Reliability of Pharyngeal High Resolution Manometry with Impedance for Derivation of Measures of Swallowing Function in Healthy Volunteers

Purpose. We evaluated the intra- and interrater agreement and test-retest reliability of analyst derivation of swallow function variables based on repeated high resolution manometry with impedance measurements. Methods. Five subjects swallowed 10 × 10 mL saline on two occasions one week apart producing a database of 100 swallows. Swallows were repeat-analysed by six observers using software. Swallow variables were indicative of contractility, intrabolus pressure, and flow timing. Results. The average intraclass correlation coefficients (ICC) for intra- and interrater comparisons of all variable means showed substantial to excellent agreement (intrarater ICC 0.85–1.00; mean interrater ICC 0.77–1.00). Test-retest results were less reliable. ICC for test-retest comparisons ranged from slight to excellent depending on the class of variable. Contractility variables differed most in terms of test-retest reliability. Amongst contractility variables, UES basal pressure showed excellent test-retest agreement (mean ICC 0.94), measures of UES postrelaxation contractile pressure showed moderate to substantial test-retest agreement (mean Interrater ICC 0.47–0.67), and test-retest agreement of pharyngeal contractile pressure ranged from slight to substantial (mean Interrater ICC 0.15–0.61). Conclusions. Test-retest reliability of HRIM measures depends on the class of variable. Measures of bolus distension pressure and flow timing appear to be more test-retest reliable than measures of contractility.

Objective prediction of pharyngeal swallow dysfunction in dysphagia through artificial neural network modeling

BACKGROUND

Pharyngeal pressure-flow analysis (PFA) of high resolution impedance-manometry (HRIM) with calculation of the swallow risk index (SRI) can quantify swallow dysfunction predisposing to aspiration. We explored the potential use of artificial neural networks (ANN) to model the relationship between PFA swallow metrics and aspiration and to predict swallow dysfunction.

METHODS

Two hundred consecutive dysphagia patients referred for videofluoroscopy and HRIM were assessed. Presence of aspiration was scored and PFA software derived 13 metrics and the SRI. An ANN was created and optimized over training cycles to achieve optimal classification accuracy for matching inputs (PFA metrics) to output (presence of aspiration on videofluoroscopy). Application of the ANN returned a value between 0.00 and 1.00 reflecting the degree of swallow dysfunction.

KEY RESULTS

Twenty one patients were excluded due to insufficient number of swallows (<4). Of 179, 58 aspirated and 27 had aspiration pneumonia history. The SRI was higher in aspirators (aspiration 24 [9, 41] vs no aspiration 7 [2, 18], p < 0.001) and patients with pneumonia (pneumonia 27 [5, 42] vs no pneumonia 8 [3, 24], p < 0.05). The ANN Predicted Risk was higher in aspirators (aspiration 0.57 [0.38, 0.82] vs no aspiration 0.13 [0.4, 0.25], p < 0.001) and in patients with pneumonia (pneumonia 0.46 [0.18, 0.60] vs no pneumonia 0.18 [0.6, 0.49], p < 0.01). Prognostic value of the ANN was superior to the SRI.

CONCLUSIONS & INFERENCES

In a heterogeneous cohort of dysphagia patients, PFA with ANN modeling offers enhanced detection of clinically significant swallowing dysfunction, probably more accurately reflecting the complex interplay of swallow characteristics that causes aspiration.

Maximum upper esophageal sphincter (UES) admittance: a non-specific marker of UES dysfunction

BACKGROUND

Assessment of upper esophageal sphincter (UES) motility is challenging, as functionally, UES relaxation and opening are distinct. We studied novel parameters, UES admittance (inverse of nadir impedance), and 0.2-s integrated relaxation pressure (IRP), in patients with cricopharyngeal bar (CPB) and motor neuron disease (MND), as predictors of UES dysfunction.

METHODS

Sixty-six healthy subjects (n = 50 controls 20-80 years; n = 16 elderly >80 years), 11 patients with CPB (51-83 years) and 16 with MND (58-91 years) were studied using pharyngeal high-resolution impedance manometry. Subjects received 5 × 5 mL liquid (L) and viscous (V) boluses. Admittance and IRP were compared by age and between groups. A p < 0.05 was considered significant.

KEY RESULTS

In healthy subjects, admittance was reduced (L: p = 0.005 and V: p = 0.04) and the IRP higher with liquids (p = 0.02) in older age. Admittance was reduced in MND compared to both healthy groups (Young: p < 0.0001 for both, Elderly L: p < 0.0001 and V: p = 0.009) and CPB with liquid (p = 0.001). Only liquid showed a higher IRP in MND patients compared to controls (p = 0.03), but was similar to healthy elderly and CPB patients. Only admittance differentiated younger controls from CPB (L: p = 0.0002 and V: p < 0.0001), with no differences in either parameter between CPB and elderly subjects.

CONCLUSIONS & INFERENCES

The effects of aging and pathology were better discriminated by UES maximum admittance, demonstrating greater statistical confidence across bolus consistencies as compared to 0.2-s IRP. Maximum admittance may be a clinically useful determinate of UES dysfunction.

Assessing Upper Esophageal Sphincter Function in Clinical Practice: a Primer

The upper esophageal sphincter constitutes an important anatomic and functional landmark in the physiology of pharyngeal swallowing. A variety of clinical circumstances may call for a dedicated evaluation of this mechanism, from the etiologic evaluation of indeterminate symptoms to the generation of complex locoregional therapeutic strategies. Multiple diagnostic tools exist for the assessment of pharyngeal swallowing generally and of upper esophageal sphincter function specifically, some well established and others not yet settled into routine practice. This report reviews five specific modalities for use in making this assessment, outlining the strengths, weaknesses, and logistical considerations of each with respect to its potential use in clinical settings. In many cases, these studies will provide complementary information regarding pharyngeal function, suggesting the relative advantage of a multimodal evaluation.