The Natural Swallow: Factors Affecting Subject Choice of Bolus Volume and Pharyngeal Swallow Parameters in a Self-selected Swallow

The Manometric Representation of the Upper Esophageal Sphincter During the Resting State: A Descriptive Study

The upper esophageal sphincter (UES) is the high-pressure zone marking the transition between the hypopharynx and esophagus. There is limited research surrounding the resting UES using pharyngeal high-resolution manometry (HRM) and existing normative data varies widely. This study describes the manometric representation of the resting UES using a clinically accessible method of measurement. Data were obtained from 87 subjects in a normative database of pharyngeal HRM with simultaneous videofluoroscopy. The resting UES manometric region was identified and ten measurement segments of this region were taken throughout the duration of the study using the Smart Mouse function within the manometry software. Intraclass correlation coefficients (ICC) were used to analyze within-subject reliability across measurements. Linear mixed-effects regression models were used to analyze how subject characteristics and manometric conditions influence resting UES pressure. There was excellent within-subject reliability between resting UES mean pressures (ICC = 0.96). In bivariate analysis, there were significant effects of age, number of sensors contained within the resting UES, and preceding swallow volume on mean resting UES pressure. For every 1 unit increase in age, there was a 0.19 unit decrease in resting UES pressure (p = 0.008). For every 1 unit increase in number of sensors contained within the resting UES, there was a 3.71 unit increase in resting UES pressure (p < 0.001). This study presents normative data for the resting UES, using a comprehensive and clinically accessible protocol that can provide standard comparison for the study of populations with swallowing disorders, particularly UES dysfunction, and provides support for UES-directed interventions.

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.

Advancements and Challenges in Non-Invasive Sensor Technologies for Swallowing Assessment: A Review

Dysphagia is a pervasive health issue that impacts diverse demographic groups worldwide, particularly the elderly, stroke survivors, and those suffering from neurological disorders. This condition poses substantial health risks, including malnutrition, respiratory complications, and increased mortality. Additionally, it exacerbates economic burdens by extending hospital stays and escalating healthcare costs. Given that this disorder is frequently underestimated in vulnerable populations, there is an urgent need for enhanced diagnostic and therapeutic strategies. Traditional diagnostic tools such as the videofluoroscopic swallowing study (VFSS) and flexible endoscopic evaluation of swallowing (FEES) require interpretation by clinical experts and may lead to complications. In contrast, non-invasive sensors offer a more comfortable and convenient approach for assessing swallowing function. This review systematically examines recent advancements in non-invasive swallowing function detection devices, focusing on the validation of the device designs and their implementation in clinical practice. Moreover, this review discusses the swallowing process and the associated biomechanics, providing a theoretical foundation for the technologies discussed. It is hoped that this comprehensive overview will facilitate a paradigm shift in swallowing assessments, steering the development of technologies towards more accessible and accurate diagnostic tools, thereby improving patient care and treatment outcomes.

High-resolution manometry with impedance for the study of pharyngeal motility and the upper esophageal sphincter: Keys for its use in the study of the pathophysiology of oropharyngeal dysphagia

Oropharyngeal dysphagia (OD) is a pathology with a high prevalence in different patient phenotypes. High-resolution pharyngoesophageal manometry (HRPM) with impedance (HRPM-I) has become in recent years a fundamental technique for better understanding the pathophysiology of pharynx and upper oesophageal sphincter (UES) dysfunctions in patients with OD. Various groups of experts have proposed a methodology for the practice of the HRPM-I and for the standardization of the different metrics for the study of pharyngeal motility and UES dysfunctions based on the quantification of 3main phenomena: relaxation of the UES, resistance to flow through the UES and propulsion of the bolo through the pharynx into the oesophagus. According to the alterations of these metrics, 3patterns of dysfunction are proposed that allow a specific therapeutic approach: (a) UES flow restriction with normal pharyngeal propulsión; (b) UES flow restriction with ineffective pharyngeal propulsion, and (c) ineffective pharyngeal contraction with normal relaxation of the UES. We present a practical review of the methodology and metrics used by the main working groups together with the description of the main patterns of dysfunction according to our experience to highlight the usefulness of the HRPM-I in the study of the pathophysiology and selection of a specific treatment in patients with OD.

Normative High-Resolution Pharyngeal Manometry: Impact of Age, Size of System, and Sex on Primary Metrics and Pressure Stability

There have been many reports of normative pharyngeal swallowing pressures using high-resolution pharyngeal manometry, but there is a fair amount of between-subject variance in reported pressure parameters. The purpose of this study was to put forward normative pharyngeal high-resolution manometry measures across the lifespan and investigate the effects of age, size of system, and sex. High-resolution pharyngeal manometry was performed on 98 healthy adults (43 males) between the ages 21 and 89. Pressure duration, maxima, integral, and within-individual variability metrics were averaged over 10 swallows of 10-ml thin liquid. Multiple linear and logistic regressions with model fitting were used to examine how pharyngeal pressures relate to age, pharyngeal size, and sex. Age was associated with tongue base maximum pressure, tongue base maximum variability, and upper esophageal sphincter-integrated relaxation pressure (F3,92 = 6.69; p < 0.001; adjusted R2 = 0.15). Pharyngeal area during bolus hold was associated with velopharynx integral (F1,89 = 5.362; p = 0.02; adjusted R2 = 0.05), and there was no significant model relating pharyngeal pressures to C2-C4 length (p < 0.05). Sex differences were best described by tongue base integral and hypopharynx maximum variability (χ2 = 10.27; p = 0.006; pseudo R2 = 0.14). Normative data reveal the distribution of swallow pressure metrics which need to be accounted for when addressing dysphagia patients, the importance of pressure interactions in normal swallow, and address the relative stability of swallow metrics with normal aging.

Using high resolution manometry impedance to diagnose upper esophageal sphincter and pharyngeal motor disorders

BACKGROUND

Oro-pharyngeal pathophysiology, including upper esophageal sphincter (UES) and pharyngeal disorders, can be assessed by pharyngeal high-resolution manometry impedance (P-HRM-I). We aimed to establish methodology to diagnose disorders utilizing P-HRM-I, hypothesizing that the objective measures could be used to diagnose disordered deglutition evidenced by greater aspiration scores.

METHODS

Patients (n = 509, 18-91 years) were compared to controls (n = 120, 20-94 years). Variables measuring UES relaxation, UES opening extent, intrabolus pressure, and pharyngeal contractile strength were derived for 10 ml liquid swallows. Three associated pharyngeal pressurization patterns, which may be indicative of obstructed flow, were characterized: pan-pressurization (Type 1), distal compartmentalized pressurization (Type 2), and transient pressurization (Type 3). Deglutitive aspiration was determined from video fluoroscopy.

RESULTS

UES relaxation pressure was best able to differentiate patients from controls (T 6.528, p < 0.0001). Patients with abnormal relaxation pressure (>8 mmHg) more frequently exhibited pharyngeal pressurization patterns and had adjunct evidence of reduced luminal distensibility (high intrabolus pressure and/or reduced UES opening). Utilizing this information, a diagnostic scheme was devised identifying 138 patients with UES disorder. A further 96 patients without evidence of UES disorder had abnormally weak pharyngeal pressures, confirming propulsive disorder. Amongst a sub-sample of 320 patients undergoing video fluoroscopy, those with pharyngeal pressurizations and adjunct evidence of reduced UES relaxation and/or distensibility had higher aspiration scores (Chi-square 60.169, p < 0.0001).

CONCLUSION

P-HRM-I can provide evidence for UES disorder based on pharyngeal pressurization patterns and abnormal findings for UES relaxation pressure, UES opening, and intrabolus pressure. Measuring pharyngeal contractility requires further optimization.

Swallow Safety and Laryngeal Kinematics: A Comparison of Dysphagia Between Parkinson's Disease and Cerebrovascular Accident

BACKGROUND

Cerebrovascular accident (CVA) and Parkinson's disease (PD) are well established etiologies of dysphagia. However, differing physiological mechanisms underlying dysphagia may exist between these two causes. There have been limited investigations specifically comparing dysphagia between these two groups. Comparing dysphagia presentation in two different populations may improve clinical expectations, guide treatment approaches, and inform future research.

OBJECTIVE

This study examined the differences in presentation of dysphagia between PD and CVA. Dysphagia presentation, swallow safety, and laryngeal kinematics were compared between two clinical cohorts. What factors best predicted airway invasion in each group were explored.

METHODS

110 swallow studies of individuals with PD and CVA who were referred for swallowing evaluation were obtained. Each video was analyzed for quantitative dysphagia presentation using the Videofluoroscopic Dysphagia Scale (VDS), swallow safety using the Penetration-Aspiration scale, and kinematic timings of the laryngeal vestibule (time-to-laryngeal vestibule closure [LVC] and closure duration [LVCd]).

RESULTS

Frequencies of penetration or aspiration were similar between groups. The PD group displayed significantly greater pharyngeal stage swallow impairment than CVA, with more frequent reduced laryngeal elevation and increased vallecular residue. The CVA group displayed significantly greater oral stage impairment, with prolonged oral transit times. Time-to-LVC was significantly prolonged and was the strongest predictor of airway invasion in the PD group, but not for CVA.

CONCLUSION

Similar airway invasion rates for PD and CVA indicate the importance of screening for dysphagia in PD. Laryngeal kinematics as significant contributors to airway invasion in PD but not for CVA highlight the need for further research into these mechanisms and for targeted treatment approaches to dysphagia.

Swallow Safety and Laryngeal Kinematics: A Comparison of Dysphagia Between Parkinson's Disease and Cerebrovascular Accident

BACKGROUND

Cerebrovascular accident (CVA) and Parkinson's disease (PD) are well established etiologies of dysphagia. However, differing physiological mechanisms underlying dysphagia may exist between these two causes. There have been limited investigations specifically comparing dysphagia between these two groups. Comparing dysphagia presentation in two different populations may improve clinical expectations, guide treatment approaches, and inform future research.

OBJECTIVE

This study examined the differences in presentation of dysphagia between PD and CVA. Dysphagia presentation, swallow safety, and laryngeal kinematics were compared between two clinical cohorts. What factors best predicted airway invasion in each group were explored.

METHODS

110 swallow studies of individuals with PD and CVA who were referred for swallowing evaluation were obtained. Each video was analyzed for quantitative dysphagia presentation using the Videofluoroscopic Dysphagia Scale (VDS), swallow safety using the Penetration-Aspiration scale, and kinematic timings of the laryngeal vestibule (time-to-laryngeal vestibule closure [LVC] and closure duration [LVCd]).

RESULTS

Frequencies of penetration or aspiration were similar between groups. The PD group displayed significantly greater pharyngeal stage swallow impairment than CVA, with more frequent reduced laryngeal elevation and increased vallecular residue. The CVA group displayed significantly greater oral stage impairment, with prolonged oral transit times. Time-to-LVC was significantly prolonged and was the strongest predictor of airway invasion in the PD group, but not for CVA.

CONCLUSION

Similar airway invasion rates for PD and CVA indicate the importance of screening for dysphagia in PD. Laryngeal kinematics as significant contributors to airway invasion in PD but not for CVA highlight the need for further research into these mechanisms and for targeted treatment approaches to dysphagia.