Effect of aging on bolus kinematics during the pharyngeal phase of swallowing

The Impact of Bolus Rheology on Physiological Swallowing Parameters Derived by Pharyngeal High-Resolution Manometry Impedance

BACKGROUND

The shear rheology of ingested fluids influences their pharyngo-esophageal transit during deglutition. Thus, swallowed fluids elicit differing physiological responses due to their shear-thinning profile.

METHODS

Two hydrocolloid fluids, xanthan gum (XG) and sodium carboxymethylcellulose gum (CMC), were compared in 10 healthy adults (mean age 39 years). Manometry swallowing assessments were performed using an 8-French catheter. Swallows were analyzed using the Swallow Gateway web application (www.swallowgateway.com). Grouped data were analyzed by a mixed statistical model. The coefficient of determination (r2) assessed the relationship between measures and bolus viscosity (SI units, mPa.s) at shear rates of 1-1000 s-1.

KEY RESULTS

Rheology confirmed that the thickened fluids had similar viscosities at 50 s-1 shear rate (XG IDDSI Level-1, 2, and 3 respectively, 74.3, 161.2, and 399.6 mPa.s vs. CMC Level-1, 2, and 3 respectively 78.0, 176.5, and 429.2 mPa.s). However, at 300 s-1 shear, CMC-thickened fluids exhibited approximately double the viscosity (XG Level-1, 2, and 3 respectively 19.5, 34.4, and 84.8 mPa.s vs. CMC Level-1, 2, and 3 respectively, 41.3, 80.8, and 160.2 mPa.s). In vivo swallows of CMC, when compared to XG, showed evidence of greater flow resistance, such as increased intrabolus pressure (p < 0.01) and UES Integrated Relaxation Pressure (UESIRP, p < 0.01) and shorter UES Relaxation Time (p < 0.05) and Bolus Presence Time (p < 0.001). The apparent fluid viscosity (mPa.s) correlated most significantly with increasing UESIRP (r2 0.69 at 50 s-1 and r2 0.97 at 300 s-1, p < 0.05).

CONCLUSION

Fluids with divergent shear viscosities demonstrated differences in pharyngeal function. These physiological responses were linked to the shear viscosity and not the IDDSI level.

The development of thickened fermented rice milk formulation for people with dysphagia: A view of multiple in vitro simulation methods

Based on the huge blank of thickened fluid staple food for people with dysphagia, multiple in vitro simulations were utilized to develop the thickened fermented rice milk. Here, the effect of amylase content, hydrolysis time and thickener content were considered. The rheological study and Cambridge throat evaluation revealed that hydrolysis could significantly reduce the viscosity and yield stress of fermented rice milk, accompanied by the decreased swallowing residue. The addition of thickeners increased the viscosity and cohesion of the fermented rice milk due to the entanglement network formation, which facilitated the formation of lubricating film, decreased the coefficient of friction, and improved the sensory score. Increasing thickener content from 0 % to 0.5 % induced the longer oral transition time (0.26 s to 0.45 s), more residue (0.85 g to 2.07 g) and shorter stretching length (850.42 mm to 313.62 mm) shown in the Cambridge throat simulation. Among them, the fermented rice milk with 0.40 % thickener showed the best sensory properties, and its swallowing properties evaluated by computer simulation also suggested concentrated frequency distribution of velocity, shear rate and viscosity without splashing or choking compared with the normal fermented rice milk, showing excellent swallowing safety.

Physiologically based pharmacokinetic (PBPK) modelling of oral drug absorption in older adults - an AGePOP review

The older population consisting of persons aged 65 years or older is the fastest-growing population group and also the major consumer of pharmaceutical products. Due to the heterogenous ageing process, this age group shows high interindividual variability in the dose-exposure-response relationship and, thus, a prediction of drug safety and efficacy is challenging. Although physiologically based pharmacokinetic (PBPK) modelling is a well-established tool to inform and confirm drug dosing strategies during drug development for special population groups, age-related changes in absorption are poorly accounted for in current PBPK models. The purpose of this review is to summarise the current state-of-knowledge in terms of physiological changes with increasing age that can influence the oral absorption of dosage forms. The capacity of common PBPK platforms to incorporate these changes and describe the older population is also discussed, as well as the implications of extrinsic factors such as drug-drug interactions associated with polypharmacy on the model development process. The future potential of this field will rely on addressing the gaps identified in this article, which can subsequently supplement in-vitro and in-vivo data for more robust decision-making on the adequacy of the formulation for use in older adults and inform pharmacotherapy.

Rheological Issues on Oropharyngeal Dysphagia

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

Role of fluid cohesiveness in safe swallowing

In patients with dysphagia, it has been a practice to thicken fluid food to prevent aspiration-the transport of a bolus into the trachea instead of the oesophagus. In these patients, aspiration is a risk behaviour and is closely related to pneumonia (caused by the aspiration of oral bacteria into the lungs). Since excessive thickening of fluids can cause adverse effects, such as lowering the palatability of food, subsequent reduction of liquid intake, dehydration and malnutrition, identifying the optimum thickening level is vital. Thickening might not only increase fluid viscosity, but could also modify its cohesiveness, which is another key factor affecting aspiration. Even though cohesiveness is more of a concept than a well-defined measurable parameter, this property describes the degree of coherency provided by the internal structure of a material against its fractional breakup. In fluids, this concept is less explored than in solids, powders and granules, and during the last decade few scientists have tackled this topic. Although the role of cohesiveness in the swallowing of heterogeneous solid foods is briefly overviewed, the aim of the present paper is to introduce the concept of cohesiveness for a relatively homogeneous fluid bolus and its effect on swallowing. Cohesiveness is highly correlated with the extensibility and yield stress of the fluid, suggesting that a high cohesiveness could have an important role in preventing aspiration.

Systematic Review of Pharyngeal and Esophageal Manometry in Healthy or Dysphagic Older Persons (>60 years)

We undertook a systematic review of swallowing biomechanics, as assessed using pharyngeal and esophageal manometry in healthy or dysphagic older individuals aged over 60 years of age, comparing findings to studies of younger participants. PRISMA-P methodology was used to identify, select, and evaluate eligible studies. Across studies, older participants had lower upper esophageal sphincter (UES) resting pressures and evidence of decreased UES relaxation when compared to younger groups. Intrabolus pressures (IBP) above the UES were increased, demonstrating flow resistance at the UES. Pharyngeal contractility was increased and prolonged in some studies, which may be considered as an attempt to compensate for UES flow resistance. Esophageal studies show evidence of reduced contractile amplitudes in the distal esophagus, and an increased frequency of failed peristaltic events, in concert with reduced lower esophageal sphincter relaxation, in the oldest subjects. Major motility disorders occurred in similar proportions in older and young patients in most clinical studies, but some studies show increases in achalasia or spastic motility in older dysphagia and noncardiac chest pain patients. Overall, study qualities were moderate with a low likelihood of bias. There were few clinical studies specifically focused on swallowing outcomes in older patient groups and more such studies are needed.

Nutritional Aspects of Dysphagia Management

This chapter describes the nutritional aspects of dysphagia management by starting with the definition of these two conditions (dysphagia and malnutrition) that share three main clinical characteristics: (a) their prevalence is very high, (b) they can lead to severe complications, and (c) they are frequently underrecognized and neglected conditions. From an anatomical standpoint, dysphagia can result from oropharyngeal and/or esophageal causes; from a pathophysiological perspective, dysphagia can be caused by organic or structural diseases (either benign or malignant) or diseases causing impaired physiology (mainly motility and/or perception disorders). This chapter gathers up-to-date information on the screening and diagnosis of oropharyngeal dysphagia, the consequences of dysphagia (aspiration pneumonia, malnutrition, and dehydration), and on the nutritional management of dysphagic patients. Concerning this last topic, this chapter reviews the rheological aspects of swallowing and dysphagia (including shear and elongational flows) and its influence on the characteristics of the enteral nutrition for dysphagia management (solid/semisolid foods and thickened liquids; ready-to-use oral nutritional supplements and thickening powders), with special focus on the real characteristics of the bolus after mixing with human saliva.

Esophageal morphometric and biomechanical changes during aging in rats

BACKGROUND

Human studies have demonstrated aging-related changes in esophagus which may contribute to the increased rate of gastro-esophageal reflux in elderly. The aim of this study was to investigate esophageal morphometric and biomechanical remodeling in aging rats to obtain detailed information about aging-related changes.

METHODS

Twenty-four male Wistar rats, aged from 6 to 22 months, were studied. Morphometric data were obtained by measuring the wall thickness and cross-sectional area. The esophageal diameter and length were obtained from digitized images of the segments at preselected luminal pressure levels and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data, and from the zero-stress state geometry.

KEY RESULTS

The esophageal parameters such as the weight per unit length, the wall thickness and the wall cross-sectional area increased slightly from 6 to 22 months (p < 0.05 to p < 0.001). The opening angle gradually decreased during aging (p < 0.05). The interface between the mucosa-submucosa and muscle layers slightly moved outwards and the neutral axis moved inwards during aging. The stress-strain data showed that the esophageal wall became stiffer circumferentially and longitudinally during aging (p < 0.05, p < 0.01). However, the circumferential wall stiffness showed no further change after 12 months.

CONCLUSIONS & INFERENCES

A pronounced morphometric and biomechanical remodeling occurred in the rat esophagus during aging.

Effects of Age and Bolus Volume on Velocity of Hyolaryngeal Excursion in Healthy Adults

Reduced movement velocity has been identified as a risk marker for movement impairment in older adults. Hyolaryngeal excursion is a key movement feature of normal swallowing function which is known to change with age and other extrinsic variables such as bolus volume. However, velocity of hyolaryngeal excursion has received limited attention in the literature on normal or abnormal swallowing. This study evaluated the effects of age and bolus volume on the velocity of hyoid and laryngeal excursion during swallowing in healthy adults. Forty-four healthy volunteers were grouped into three age bands (young: 20-35 years, middle age: 36-55 years, older: 56 ≥ years). All subjects swallowed 5 and 20 mL of thin liquid during fluoroscopic recording. Fluoroscopic images were extracted for each swallow representing the onset and maximum excursion positions of the hyoid and larynx. Superior and anterior excursion distance (excursion magnitude) and the time difference between rest and maximum excursion (excursion duration) were calculated. Velocity was calculated as a ratio of distance over time. Superior hyoid excursion magnitude was significantly increased for the 20 mL volume. Anterior laryngeal excursion magnitude was also significantly increased for the 20 mL volume. No kinematic duration measure demonstrated significant change across age or bolus conditions. Superior hyoid excursion velocity was significantly faster for the 20 mL volume. Superior and anterior laryngeal excursion velocity were significantly faster for the 20 mL volume only in the older group. Results of this study indicate that magnitude and velocity of hyoid and laryngeal excursion vary with age and volume. Comprising both excursion magnitude and duration, kinematic velocity may be a more complete metric to evaluate age-related swallowing performance.

Impact of nasogastric tubes on swallowing physiology in older, healthy subjects: A randomized controlled crossover trial

BACKGROUND & AIMS

The presence of a nasogastric tube (NGT) affects swallowing physiology but not function in healthy young adults. The swallowing mechanism changes with increasing age, therefore the impact of a NGT on swallowing in elderly individuals is likely to be different but is not yet known. The aims of this study were to determine the effects of NGTs of different diameter on (1) airway penetration-aspiration, (2) pharyngeal residue, and (3) pharyngeal transit, in older healthy subjects.

METHODS

Randomized controlled crossover design. Healthy elderly volunteers underwent 3 modified barium swallow studies in which multiple diet and fluid consistencies were swallowed under the following conditions: (A) no NGT (control), (B) fine bore NGT, and (C) wide bore NGT. The control condition was assessed first to establish baseline swallowing function, then NGT order was randomly allocated.

RESULTS

Of the 15 volunteers (median age 65 years, range 60-81) complete data sets were obtained for 9 (4 with allocation order ABC; 5 with ACB). Wide bore NGT data could not be obtained for 6 volunteers mainly due to tube intolerance. The presence of a NGT was associated with: (i) an increase in airway penetration-aspiration (fine bore NGT with serial liquid swallows and puree) (p < 0.01); (ii) increased pharyngeal residue (p < 0.05) in the pyriform sinus (fine bore NGT with puree); and in the valleculae (both fine and wide bore NGT with soft solids); and (iii) an increase in pharyngeal transit duration regardless of consistency (p < 0.01), with longest swallowing durations with the widest tube.

CONCLUSIONS

NGT presence increases airway penetration-aspiration, pharyngeal residue and prolongs transit through the pharynx in older healthy individuals. Consideration of NGT impact on swallowing during concurrent oral and enteral feeding is recommended, with further systematic investigation required in elderly patients recovering from critical illness. Clinical trial registry Australia & New Zealand Clinical Trials Registry (ACTRN12613000577718).

Swallowing dysfunction in healthy older people using pharyngeal pressure-flow analysis

BACKGROUND

Age-related loss of swallowing efficiency may occur for multiple reasons. Objective assessment of individual dysfunctions is difficult and may not clearly differentiate these from normal. Pharyngeal pressure-flow analysis is a novel technique that allows quantification of swallow dysfunction predisposing to aspiration risk based on a swallow risk index (SRI). In this study, we examined the effect of ageing on swallow function.

METHODS

Studies were performed in 68 healthy subjects aged 20-91 years (mean 59 years; 29 male), asymptomatic for oropharyngeal disease. Swallowing of liquid and viscous boluses was recorded with a pressure-impedance catheter. Indices of swallow function including the SRI, postswallow residues, upper esophageal sphincter opening and bolus transit time were derived using purpose designed software.

KEY RESULTS

Swallow function worsened with increasing age with a significant decline after 80 years. Higher SRI correlated with increasing age (r = 0.257, p < 0.05 for liquids and r = 0.361, p < 0.005 viscous bolus). Subjects over 80 years were overrepresented amongst those with an SRI considered diagnostically relevant (SRI > 15). In addition, upper esophageal sphincter opening was reduced and postswallow residues increased in older subjects.

CONCLUSIONS & INFERENCES

Pharyngeal pressure-flow analysis reveals multiple functional abnormalities in older individuals. The higher SRI levels seen in asymptomatic elders possibly reflect a loss of functional reserve with ageing. Automated impedance manometry analysis of swallow function may allow the risk of developing disordered swallowing to be quantified numerically.

Videofluorographic assessment of deglutitive behaviors in a rat model of aging and Parkinson disease

Dysphagia is commonly associated with aging and Parkinson disease and can have a significant impact on a person's quality of life. In some cases, dysphagia may be life-threatening. Animal models may be used to study underlying mechanisms of dysphagia, but paradigms that allow adequate imaging of the swallow in combination with measurement of physiological variables have not been forthcoming. To begin development of methods that allow this, we used videofluorography to record the deglutition behaviors of 22 Fisher 344/Brown Norway rats in young adult (9 months old), old (32 months old), and parkinsonian (unilateral lesion to the medial forebrain bundle) groups. We hypothesized that the old and parkinsonian rats would manifest deficits in deglutition behaviors analogous to those found in human clinical populations. Our results supported our hypothesis in that the old group demonstrated reductions in bolus transport speeds and mastication rate while the parkinsonian rats showed impairments in oral processing. Interpretation of these results should consider the particular animal model, lesion type, and videofluorographic protocol used in this work. Future studies will link swallow imaging data of this kind with physiological and anatomical data in a manner not possible with human participants.

Ultrasonographic evaluation of geniohyoid muscle movement during swallowing: a study on healthy adults of various ages

Our purpose in this study was to investigate the application of B+M-mode ultrasound (B/M-mode) imaging as a new approach to quantifying activity patterns of the geniohyoid muscles during swallowing and to assess how these patterns differ according to age and gender. Sixty healthy volunteers (30 men, 30 women) were divided into three age groups (20-39, 40-59, 60-79 years). The subjects were then given 10 ml of mineral water. Ultrasonographic imaging was repeated 5 times and measurements were averaged. Simultaneous B/M-mode images were captured at two regions along the lateral geniohyoid muscle wall. All geniohyoid muscle movement was recorded by real-time B/M-mode. In all cases, ultrasonographic images of the geniohyoid muscle movement during swallowing were easily visualized with the use of real-time B/M-mode. The average moving distance and the duration of movement of the geniohyoid muscle during contraction increased gradually with age. There was a significant difference in ultrasonic measurements of the moving distance and the duration of movement during swallowing between males and females in the three age groups (P < 0.05). B/M-mode imaging provides a simple, noninvasive technique for visual assessment of the lateral geniohyoid muscle wall and may provide a clinical method for evaluating swallowing.

Pharyngeal pressure generation during tongue-hold swallows across age groups

PURPOSE

To compare the effects of the tongue-hold swallowing maneuver on pharyngeal pressure generation in healthy young and elderly research volunteers.

METHOD

Sixty-eight healthy research volunteers (young, n = 34, mean age = 26.8 years, SD = 5.5; elderly, n = 34, mean age = 72.6 years, SD = 4.8; sex equally represented) performed 5 noneffortful saliva swallows and 5 tongue-hold swallows each. Amplitude and duration of pharyngeal pressure were investigated during both swallowing conditions with solid-state pharyngeal manometry at the level of the oropharynx, hypopharynx, and upper esophageal sphincter (UES).

RESULTS

At both pharyngeal levels, tongue-hold swallows produced lower peak pressure compared with saliva swallows. During tongue-hold swallows, UES relaxation pressure was increased in the elders, whereas the younger group displayed a trend toward reduced relaxation pressure. Elderly individuals produced pressure longer during control swallows in the oropharynx and hypopharynx than young individuals.

CONCLUSIONS

The tongue-hold maneuver affects oropharyngeal and hypopharyngeal pressure in the young and elders in similar ways, whereas effects on UES peak relaxation pressure differ between age groups. Reduced pharyngeal peak pressure and increased UES relaxation pressure underscore the notion that tongue-hold swallows should not be performed when bolus is present. Long-term training effects remain to be investigated.

A method to objectively assess swallow function in adults with suspected aspiration

BACKGROUND & AIMS

Pharyngeal manometry and impedance provide information on swallow function. We developed a new analysis approach for assessment of aspiration risk.

METHODS

We studied 20 patients (30-95 years old) with suspected aspiration who were referred for videofluoroscopy, along with controls (ages 24-47 years). The pharyngeal phase of liquid bolus swallowing was recorded with manometry and impedance. Data from the first swallow of a bolus and subsequent clearing swallows were analyzed. We scored fluoroscopic evidence of aspiration and investigated a range of computationally derived functional variables. Of these, 4 stood out as having high diagnostic value: peak pressure (PeakP), pressure at nadir impedance (PNadImp), time from nadir impedance to peak pressure (TNadImp-PeakP), and the interval of impedance drop in the distal pharynx (flow interval).

RESULTS

During 54 liquid, first swallows and 40 clearing swallows, aspiration was observed in 35 (13 patients). Compared to those of controls, patient swallows were characterized by a lower PeakP, higher PNadImp, longer flow interval, and shorter TNadImp-PeakP. A Swallow Risk Index (SRI), designed to identify dysfunctions associated with aspiration, was developed from iterative evaluations of variables. The average first swallow SRI correlated with the average aspiration score (r = 0.846, P < .00001 for Spearman Rank Correlation). An average SRI of 15, when used as a cutoff, predicted aspiration during fluoroscopy for this cohort (κ = 1.0).

CONCLUSIONS

Pressure-flow variables derived from automated analysis of combined manometric/impedance measurements provide valuable diagnostic information. When combined into an SRI, these measurements are a robust predictor of aspiration.

Are we testing a true thin liquid?

The purpose of this study was to examine the effects on a patient's swallowing of diluting E-Z-EM's Varibar((R)) Thin liquid barium product (which is often used in videofluoroscopic swallow studies) to achieve a consistency closer to water. Forty patients who were 18 years and older participated in this study. Their varied medical diagnoses included stroke, pneumonia, TBI, and cancer as well as diagnoses not usually associated with dysphagia such as abdominal pain and rhabdomyolysis. To screen for aspiration, E-Z-EM's Varibar Thin liquid was presented to patients to swallow as 2 cc, 5 cc, cup, and straw drinking trials. If no aspiration occurred, the patient was given the Varibar Thin liquid diluted by 50% using water (referred to as Ultrathin) to swallow in the same amounts. Then occurrence of aspiration with the Ultrathin liquid was compared to the occurrence of aspiration when the patient swallowed the Varibar Thin liquid. Fifty percent of patients aspirated on the Ultrathin liquid but not on the Varibar Thin liquid, across at least one of the test conditions. From these results we suggest that although E-Z-EM Varibar Thin liquid may have a low-viscosity range, it still may not be "thin enough" to identify all patients who aspirate or who are at risk for aspiration on thin liquids.

The clinical significance of gastrointestinal changes with aging

PURPOSE OF REVIEW

With the graying of the world's population, there is an increased interest in the physiological effects of aging. This review examines the physiological changes of the gut with aging and their clinical significance.

RECENT FINDINGS

Changes with aging in the gastrointestinal tract are variable, but in some cases they are responsible for a variety of symptoms. Thus, alterations in taste and smell, gastric motility, intestinal overgrowth and changes in gastrointestinal hormone release are the basis of the physiological anorexia of aging. Alterations in swallowing lead to silent aspiration. Changes in gastric emptying play a role in postprandial hypotension. Changes in gastrointestinal function can lead to constipation and fecal incontinence. Weakening of the colonic muscular wall produces diverticula. Achlorhydria is associated with malabsorption of some forms of iron and calcium. Vitamin D malabsorption aggravates the hypovitaminosis D that is so common in older persons. Changes in probiotics can lead to diarrhea and altered immune system. In the liver, aging is associated with delayed drug metabolism.

SUMMARY

Changes in the physiology of the gut play a role in the anorexia of aging, aspiration pneumonia, postprandial hypotension, constipation and fecal incontinence.

Sensory and instrumental analysis for slipperiness and compliance of food during swallowing

In spite of its importance, there have been few attempts to evaluate the sensory attributes of the food bolus during swallowing. In the current study, the slipperiness, the degree of slide for the food bolus through the mucosal surface of the oro-pharynx, and the compliance, how easily the shape of a food bolus can be transformed for automatic and comfortable swallowing, were derived among several sensory attributes related to the swallowing. Therefore, the study aims were twofold: (1) to develop the methods of sensory and instrumental analyses for determining the slipperiness and compliance of the food bolus during swallowing and (2) to examine the appropriateness of the newly designed devices by correlating the data between the sensory and instrumental analyses. Six commercial food products were evaluated by 10 trained panelists for each attribute. The devices for assessing each attribute were developed in consideration of the oro-pharyngeal movements. The sensory and instrumental analyses showed high correlation and regression coefficients as well as intensity differences of the 6 samples for each attribute. In conclusion, the slipperiness and the compliance were suitable for acquiring a better understanding of the sensory attributes of the food bolus during swallowing, and the newly developed devices showed a high potential for determining those attributes.

Cough and aspiration of food and liquids due to oral pharyngeal Dysphagia

Oral pharyngeal dysphagia should be included in the differential diagnosis of patients with cough. Aspiration of food and liquid below the level of the true vocal folds observed on dynamic imaging studies i.e., videofluoroscopic (VSE) and endoscopic (FEES) evaluations of swallow, has been associated with pneumonia. Coughing while eating and drinking may indicate aspiration; however, aspiration may be clinically silent. Subjective patient, caregiver, and nurse reports of reflexive cough while eating are useful but limited in identifying patients who are at risk for aspiration. Objective measures of voluntary cough are under investigation to determine their capacity to predict the risk for aspiration and subsequent pneumonia. The treatment of dysphagic patients by a multidisciplinary team, including early evaluation by a speech-language pathologist, is associated with improved outcomes. Effective clinical interventions such as the use of compensatory swallowing strategies and the alteration of food consistencies should be based on the results of instrumental swallowing studies. Reflexive cough while eating and drinking is important for the detection of oral pharyngeal dysphagia and objective measure of voluntary cough may be a good screening tool for this condition.

Dysphagia: implications for older people

This review opens with an outline definition of dysphagia, its causes, and why it is vital that people involved in the health care of older people should be aware of it. A brief consideration of prevalence is followed by an overview of assessment options. We conclude with a section on management.

Mechanical basis for lingual deformation during the propulsive phase of swallowing as determined by phase-contrast magnetic resonance imaging

The tongue is an intricately configured muscular organ that undergoes a series of rapid shape changes intended to first configure and then transport the bolus from the oral cavity to the pharynx during swallowing. To assess the complex array of mechanical events occurring during the propulsive phase of swallowing, we employed tongue pressure-gated phase-contrast MRI to represent the tissue's local strain rate vectors. Validation of the capacity of phase-contrast MRI to represent local compressive and expansive strain rate was obtained by assessing deformation patterns induced by a synchronized mechanical plunger apparatus in a gelatinous material phantom. Physiological strain rate data were acquired in the sagittal and coronal orientations at 0, 200, 400, and 600 ms relative to the gating pulse during 2.5-ml water bolus swallows. This method demonstrated that the propulsive phase of swallowing is associated with a precisely organized series of compressive and expansive strain rate events. At the initiation of propulsion, bolus position resulted from obliquely aligned compressive and expansive strain, vertically aligned compressive strain and orthogonal expansion, and compressive strain aligned obliquely to the styloid process. Bolus reconfiguration and translocation resulted from a combination of compressive strain occurring in the middle and posterior tongue aligned obliquely between the anterior-inferior and the posterior-superior regions with commensurate orthogonal expansion, along with bidirectional contraction in the distribution of the transversus and verticalis muscle fibers. These data support the concept that propulsive lingual deformation is due to complex muscular interactions involving both extrinsic and intrinsic muscles.

Deglutitive upper esophageal sphincter relaxation: a study of 75 volunteer subjects using solid-state high-resolution manometry

This study aimed to use a novel high-resolution manometry (HRM) system to establish normative values for deglutitive upper esophageal sphincter (UES) relaxation. Seventy-five asymptomatic controls were studied. A solid-state HRM assembly with 36 circumferential sensors spaced 1 cm apart was positioned to record from the hypopharynx to the stomach. Subjects performed ten 5-ml water swallows and one each of 1-, 10-, and 20-ml volume swallows. Pressure profiles across the UES were analyzed using customized computational algorithms that measured 1) the relaxation interval (RI), 2) the median intrabolus pressure (mIBP) during the RI, and 3) the deglutitive sphincter resistance (DSR) defined as mIBP/RI. The automated analysis succeeded in confirming bolus volume modulation of both the RI and the mIBP with the mean RI ranging from 0.32 to 0.50 s and mIBP ranging from 5.93 to 13.80 mmHg for 1- and 20-ml swallows, respectively. DSR was relatively independent of bolus volume. Peak pharyngeal contraction during the return to the resting state postswallow was almost 300 mmHg, again independent of bolus volume. We performed a detailed analysis of deglutitive UES relaxation with a novel HRM system and customized software. The enhanced spatial resolution of HRM allows for the accurate, automated assessment of UES relaxation and intrabolus pressure characteristics, in both cases confirming the volume-dependent effects and absolute values of these parameters previously demonstrated by detailed analysis of concurrent manometry/fluoroscopy data. Normative values were established to aid in future clinical and investigative studies.