Bolus Location at the Initiation of the Pharyngeal Stage of Swallowing in Healthy Older Adults

This study characterized the vertical position of the bolus head at the onset of the pharyngeal swallow in healthy older adults. Lateral-view videofluoroscopic (VF) images were obtained from ten healthy volunteers (age-71.6 ± 7.5 years, mean± SD) as they swallowed 5-cc thin liquid barium aliquots. For each swallow, the bolus head and several anatomic landmarks were digitally recorded from the image in which pharyngeal swallow-related hyoid bone elevation began. Vertical distance between the bolus head and the intersection of the tongue base and mandibular ramus (TMI) was computed. Bolus head position at swallow onset ranged from 47.4-mm above to 34.9-mm below the TMI (2.2 ± 14.4-mm, mean ± SD). Although the bolus head was below the level of the TMI for the majority of swallows, neither penetration nor aspiration occurred. For individual subjects, mean bolus head position ranged from 25.8 ± 5.0-mm above to 15.5 ± 6.5-mm below the TMI. Whereas five of ten subjects initiated the pharyngeal swallow with the bolus head consistently above or consistently below the TMI, five subjects initiated swallowing with the bolus head either above or below the TMI across trials. Older adults commonly initiate thin-liquid swallows with the bolus head well below the TMI without associated penetration or aspiration. Thus, bolus position alone does not differentiate between normal and pathologic swallowing within the healthy elderly. Bolus position at pharyngeal swallow onset can vary substantially from trial to trial within an individual, suggesting that the triggering of swallowing depends on multiple influences. This research was supported by NSERC grant No. 0GPO171208 and an Ontario Ministry of Health Career Scientist Award to REM.     

Quantitative assessment of swallowing in healthy adults

Swallowing has hitherto been evaluated during physical examination, radiologic barium studies, manometry, and cervical auscultation. Radiography principally demonstrates qualitative aspects of oral and pharyngeal function, whereas quantitative aspects have primarily been documented by manometry. To evaluate swallowing quantitatively, without using invasive methods or radiation, we have applied a combined test of water drinking, i.e., the Repetitive Oral Suction Swallow test (ROSS). The test provides reliable measurements of suction pressure, bolus volume, timing of important events in oral and pharyngeal swallow, and respiration. The test is described and results from 292 healthy, nondysphagic subjects are presented. We found a mean bolus volume of 25.6±8.5 ml during single swallow and 21.1±8.2 ml during stress (forced, repetitive swallow). During forced, repetitive swallow, the bolus volume was more strongly associated with suction time (r²=0.55) than with peak suction pressure (r²=0.04), indicating that suction time is more important than suction pressure in determining the bolus volume. The oral-pharyngeal transit time decreased: single swallow 0.56±0.36 sec, forced repetitive swallow 0.23±0.11 sec, as did the coefficient of variation (48% and 64%, respectively) indicating a more automatic neural process for pharyngeal function in forced, repetitive swallow. The postswallow respiration started with inspiration in 10% of studied individuals, but did not correlate with deviations in other variables in the test. Thus, postswallow inspiration must be considered as normal. The ROSS test offers a rapid and easy quantitative assessment of swallowing.     

Pharmacological Treatment of Dysphagia in Stroke

The pharynx is important for a normal swallow and it has been suggested that pharmacological agents may play a role in the management of pharyngeal dysphagia, but none have been formally evaluated. A pilot double-blind, placebo-controlled study was undertaken in 17 hospitalized patients with persistent dysphagia 2 weeks after stroke. Patients were randomized to treatment with slow-release nifedipine 30 mg orally (n = 8) or placebo (n = 9) following specialist swallowing assessment and videofluoroscopy to exclude severe dysphagia. Videofluoroscopy was repeated after 4 weeks of treatment. Fourteen patients (active 6, placebo 8) completed the study. Two patients died (active 1, placebo 1) and 1 patient in the active group had to be withdrawn because of progressive heart failure. Initial assessment showed impairment in the pharyngeal phase with delayed triggering of swallow, poor laryngeal elevation, and prolonged pharyngeal transit times in all patients. Silent aspiration was seen in 4 patients (active 2, placebo 2). Improvement in swallowing was seen in 8 patients (active 5, placebo 3) at the end of 4 weeks. There were significant changes in the pharyngeal transit time (mean −1.34 second; 95% C.I. −2.56, −0.11) and swallow delay (mean −1.91 seconds; 95% C.I. −3.58, −0.24) in the active group suggesting improvement in the initiation of pharyngeal contractions and reduction in the time taken for the bolus to transverse the pharynx. A similar change was not seen in the placebo group. It is suggested that pharmacological agents such as nifedipine may have a role in the management of stroke-related dysphagia and merit further investigation.     

Sequence Variability During Hypopharyngeal Bolus Transit

The pharyngeal phase of deglutition is considered to occur in a reflexive, preprogrammed fashion. Previous studies have determined a general sequence of events based on the mean timing of bolus transit and swallowing gestures. Individual variability has not been studied, however. The purpose of this study was to determine the amount of sequence variability that normally occurs during the hypopharyngeal phase of deglutition. Dynamic swallow studies from 60 normal volunteers were evaluated and event sequence variability was determined for 12 two-event sequences during swallowing of three bolus sizes. There was found to be some variability in event sequences for almost all events evaluated except for the following : (1) arytenoid cartilage elevation always began prior to opening of the upper esophageal sphincter, (2) the sphincter always opened prior to the arrival of the bolus at the sphincter, (3) larynx-to-hyoid approximation always occurred after the onset of upper esophageal sphincter opening, and (4) maximum pharyngeal constriction always occurred after maximal distension of the upper esophageal sphincter. Variability was more common during swallowing of the smallest bolus size. This information may be helpful in evaluating event coordination in patients with dysphagia.     

Timing Differences Between Cued and Noncued Swallows in Healthy Young Adults

Temporal parameters such as stage transition duration, bolus location at swallow onset, and pharyngeal transit time are often measured during videofluoroscopy, but these parameters may vary depending on assessment instructions. Specifically, “command” (cued) swallows have been observed to alter timing compared to spontaneous (noncued) situations in healthy older adults. The aim of our study was to confirm whether healthy young people show timing differences for thin liquid swallows between cued and noncued conditions. Twenty healthy young adults swallowed 10-cc boluses of ultrathin barium in videofluoroscopy. The cued condition was to hold the bolus in the mouth for 5 s before swallowing. Three noncued swallows were also recorded. In the cued condition, bolus advancement to the pyriform sinuses prior to swallow initiation was seen significantly less frequently. Stage transition durations showed a nonsignificant trend toward being shorter. Pharyngeal transit times and pharyngeal response time (a measure capturing the interval between hyoid movement onset and bolus clearance through the upper esophageal sphincter) were both significantly longer in the cued condition. Our study in healthy young adults confirms findings previously observed in older adults, namely, that swallow onset patterns and timing differ between cued and noncued conditions. In particular, bolus advancement to more distal locations in the pharynx at the time of swallow onset is seen more frequently in noncued conditions. This pattern should not be mistaken for impairment in swallow onset timing during swallowing assessment.     

Structural Displacements Affecting Pharyngeal Constriction in Nondysphagic Elderly and Nonelderly Adults

This study investigated spatial displacement variables important to pharyngeal constriction and clearing in nondysphagic elderly subjects and a control group of nondysphagic younger adults. Height, weight, and body mass index (BMI) characteristics were determined for all subjects, who then underwent videofluoroscopic swallow studies. Measures obtained during swallow of a 20-cc bolus included hyoid and laryngeal displacement, unobliterated pharyngeal space at the point of maximum pharyngeal constriction, and pharyngeal width when maximally expanded during the swallow. Data were first examined to determine if elderly subjects with medical conditions common to an aged population differed from elderly subjects with no medical condition. No differences were identified and data for all elderly subjects were subsequently pooled for comparison to data for the nonelderly control group. Findings revealed no differences in maximum hyoid displacement between the groups. Significant differences were identified for larynx-to-hyoid approximation and for the measure representing unobliterated pharyngeal space at the point of maximum pharyngeal constriction. Elderly subjects did not elevate the larynx to the same extent, or clear the pharynx, as well as the younger control subjects. In addition, data suggested that the larynx was positioned lower and that the width of the pharynx maximally expanded was greater in elderly subjects. Implications of the data for swallowing function in the elderly are discussed.     

Relationship Between Manometric and Videofluoroscopic Measures of Swallow Function in Healthy Adults and Patients Treated for Head and Neck Cancer with Various Modalities

Pharyngeal manometry complements the modified barium swallow with videofluoroscopy (VFS) in diagnosing pressure-related causes of dysphagia. When manometric analysis is not feasible, it would be ideal if pressure information about the swallow could be inferred accurately from the VFS evaluation. Swallowing function was examined using VFS and concurrent manometry in 18 subjects (11 head and neck patients treated with various modalities and 7 healthy adults). Nonparametric univariate and multivariate analyses revealed significant relationships between manometric and fluoroscopic variables. Increases in pressure wave amplitude were significantly correlated with increased duration of tongue base to pharyngeal wall contact, reduced bolus transit times, and oropharyngeal residue. Pharyngeal residue was the most important VFS variable in reflecting pharyngeal pressure measurements. Certain VFS measures were significantly correlated with measures of pressure assessed with manometry. Further research is needed before observations and measures from VFS alone may be deemed sufficient for determining pressure-generation difficulties during the swallow in patients who are unable or unwilling to submit to manometric testing.

The Effects of Cervical Bracing Upon Swallowing in Young,Normal, Healthy Volunteers

Abstract The purpose of this study was to evaluate radiographically the effects of cervical bracing upon swallowing thin liquids and solid food in normal adults under three cervical bracing conditions. This was a prospective, repeated measures design study. Seventeen healthy adult volunteers between the ages of 30 and 50 were recruited from hospital staff. All subjects reported no previous history of swallowing difficulty or diseases that might affect swallowing. Subjects were radiographically observed swallowing thin liquids and solid food without cervical bracing and with three common cervical orthoses (Philadelphia collar, SOMI, and halo-vest brace). Order of bracing and type of bolus were randomized. Changes in swallowing function (point of initiation of swallow response, presence of pharyngeal residue, airway penetration, hyoid bone movement, diameter of oropharyngeal airway, and durational measurements) were analyzed by two independent raters. Eighty-two percent (14/17) of the subjects demonstrated radiographic changes under one or more of the bracing conditions. Forty-seven percent (8/17) of subjects demonstrated changes with point of initiation of the swallow response, 59% (10/17) demonstrated increased pharyngeal residue, and 23.5% (4/17) demonstrated changes with bolus flow with laryngeal penetration present. Aspiration did not occur under any of the bracing conditions. Changes noted in durational measurements for oral containment and total pharyngeal transit under the bracing conditions were not considered statistically significant. This study shows that cervical bracing does change swallowing physiology in normal healthy adults.     

Volume accommodation during swallowing

Bolus volume is an important modifier of the biomechanical events of the oropharyngeal swallow. The biomechanical events comprising a swallow can be divided into events associated with the reconfiguration of the pharynx into a swallow pathway and events associated with bolus transport from the oropharynx into the esophagus. Volume modification is achieved differently for the events of reconfiguration and propulsion. In the case of reconfiguration, a longer time is allocated to the process, as exemplified by sustained laryngeal elevation and hyoid excursion during larger volume swallows. On the other hand, in the case of bolus expulsion, volume accommodation is accomplished within the same period of time by utilizing increased vigor of expulsion. The result of deglutitive volume accommodation is a remarkably different fluoroscopic appearance of a small vs. a large volume swallow. The larger volume swallow seemingly takes longer and results in much more vigorous bolus expulsion than a small volume. However, this is more related to the bolus than the swallow.     

Preliminary observations on the effects of age on oropharyngeal deglutition

Swallows of 4 bolus volumes (1, 5, 10, 20 ml) were examined in three groups of subjects: 6 subjects 20–29 years of age, 12 subjects 30–59 years of age, and 6 subjects 60–79 years of age. A simultaneous manometric and videofluoroscopic data collection protocol permitted measurement of bolus transit, temporal aspects of the oropharyngeal swallow, and pharyngeal peristalsis. Statistically significant effects of increasing bolus volume were oral transit of the bolus head (decreased) and duration of cricopharyngeal opening (increased). Five measures were significantly changed with increasing age: duration of pharyngeal swallow delay (increased), duration of pharyngeal swallow response (decreased), duration of cricopharyngeal opening (decreased), peristaltic amplitude (decreased), and peristaltic velocity (decreased).     

Food intake by maneuver; An extreme compensation for impaired swallowing

We report two young patients able to exist on exclusively oral intake despite an absent pharyngeal swallow response. Videofluoroscopic swallowing studies showed that both patients used a sequence of devised maneuvers rather than a coordinated pharyngeal swallow to move the bolus, protect the airway, and open the upper esophageal sphincter during bolus ingestion. We conclude that it is possible for young, highly motivated individuals to maintain oral intake despite ablation of neurologic elements crucial for the normal swallow response.     

Influence of cold stimulation on the normal pharyngeal swallow response

We examined the potential influence of cold stimulation of the anterior tonsillar pillars, before and after topical anesthesia, on the temporal linkage between the oral and pharyngeal components of the swallow. We hypothesized that if elicitation of the pharyngeal swallow were dependent upon stimulation of faucial mucosal receptors this response would be facilitated by cold tactile stimulation and inhibited by topical anesthesia. In 14 healthy volunteers undergoing simultaneous videoradiography and manometry we measured and compared regional transit and clearance times, and the timing of hyoid motion, upper esophageal sphincter relaxation, and opening within the swallow sequence. There was a significant, volume-dependent forward shift in timings of hyoid motion, upper esophageal sphincter (UES) relaxation profile, and opening which were influenced neither by cold stimulation nor topical anesthesia. Regional transit and clearance times and UES coordination were not influenced by cold stimulation. Pharyngeal clearance time was prolonged by tonsillar pillar anesthesia due to earlier arrival of the bolus head at this region (p=0.002). We conclude that the normal pharyngeal swallow response is neither facilitated nor inhibited by prior cold tactile stimulation or topical anesthesia to the tonsillar pillars, respectively. These observations do not support the hypothesis that elicitation of the pharyngeal swallow response is dependent upon stimulation of mucosal receptors in the tonsillar arches.     

Normal adult swallowing of liquid and viscous material: Scintigraphic data on bolus transit and oropharyngeal residues

Scintigraphic data are provided for 20 normal control subjects, 39–65 years of age. Each subject swallowed 10 cc of water and 10 cc of a more viscous material (1,100 centipoise) consisting of apple juice thickened with Thick-It, a commercial food thickener. The test substances were combined with 2.5 mCi Tc-99m sulfur colloid. Scintigraphic data were acquired in dynamic mode for 10 sec at 25 frames/sec as the subjects swallowed. Time-activity (TA) data were used to compute transit times, percentage residues in the mouth and pharynx, percent ingested, and a derived swallow efficiency score. The liquid was ingested in a single swallow by all subjects, and 9 cc was actually tranferred to the esophagus. In contrast, for the viscous material, 11/20 subjects performed a second clearing swallow within the 10-sec interval. On the first swallow with the viscous substance, an average of 7 cc was transferred to the esophagus. Scintigraphy offers an excellent technique for determining natural and preferred volumes for swallowing a variety of bolus consistencies, since it can quantify the volume of each swallow or partial swallow. In this group of subjects the oral discharge time was shorter with the viscous material than with the water, but the pharyngeal transit times were not significantly different for the two bolus consistencies. Numerical efficiency scores were lower for the viscous material, indicating that such a measure is bolus dependent.     

The Influence of Orolingual Pressure on the Timing of Pharyngeal Pressure Events

This study explored the influence of two methods of effortful swallow execution on the timing of pharyngeal pressure events. Participants were asked to either emphasize or minimize tongue-to-palate contact during performance of the maneuver. Twenty healthy participants were evaluated using concurrent submental surface electromyography (sEMG), orolingual manometry, and pharyngeal manometry. Each subject performed three repetitions of three counterbalanced tasks (noneffortful dry swallows, effortful dry swallows with tongue-to-palate emphasis, and effortful dry swallows with tongue-to-palate de-emphasis). Four variables were measured: Onset Lag vs. sEMG Peak, Peak Lag vs. sEMG Peak, Total Duration, and Percent Rise Time to Peak. Compared to noneffortful swallows, the effortful swallow task elicited significantly earlier onsets and peaks of pharyngeal pressures relative to the submental sEMG peak. Total pressure event durations were greater and rise times were significantly shorter. When comparing the two methods of effortful swallow execution, a longer latency to peak proximal pharyngeal pressure was found in the tongue-to-palate emphasis condition. These results support the interpretation that the effortful swallow maneuver involves generation of higher velocity bolus driving forces that propel the bolus into and through the pharynx with greater efficiency and that pressure is then sustained to facilitate more complete bolus clearance. Work performed at the Van der Veer Institute for Parkinson’s and Brain Research, Christchurch, New Zealand     

Effects of Bolus Consistency on Timing and Safety of Swallow in Patients with Parkinson’s Disease

Aspiration pneumonia is the leading cause of death in Parkinson’s disease (PD) patients. In clinical practice, the videofluoroscopic examination (VFE) is the most common method for evaluation of swallowing disorders. One of the variables manipulated during the VFE is consistency of the bolus. The results of this examination greatly influence the recommendations made by speech-language pathologists regarding swallow therapy and/or intervention. The primary aim of this study was to investigate the effects of bolus consistency on penetration-aspiration (P-A) score and timing of swallow of persons with PD. The videoradiographic images of ten participants with PD swallowing six thin and six pudding-thick boluses were analyzed. Swallow timing and P-A were measured. (i.e., oral transit time, pharyngeal transit time, number of tongue pumps, and P-A score). The results demonstrated various significant differences and relationships among the dependent variables. Implications for further research and clinical practice are discussed.     

A Scintigraphic Study of Oral, Pharyngeal, and Esophageal Transit in Patients with Stroke

Although stroke affects mainly the oral and pharyngeal phases of swallowing, it may also impair esophageal contractions. Our hypothesis is that stroke may affect esophageal transit. The oral, pharyngeal, and esophageal transit was studied by the scintigraphic method in 26 patients (age range=26-83 years), eight of whom had mild dysphagia but all were able to feed orally and who had suffered an acute first-ever ischemic stroke 10-56 days (median = 43 days) before transit evaluation. The control group included 15 healthy volunteers (age range=27-86 years). All subjects swallowed a 5-ml liquid bolus and a 5-ml paste bolus labeled with technetium-99m phytate while sitting in front of the collimator of a gamma camara. The oral, pharyngeal, and proximal, middle, and distal esophageal transit was measured for 20 s. Three patients did not swallow the bolus during the scintigraphic evaluation. There was no difference between patients and controls with respect to oral and pharyngeal transit or clearance of liquid. For paste, the pharyngeal transit time was shorter for patients (0.48+/-0.17 s) than for controls (0.61+/-0.18 s, p=0.027). Also for the paste bolus, the residue in the mouth was greater in patients (18.4+/-13.6%) than in controls (10.2+/-4.9%, p=0.031). The liquid transit duration in the distal esophagus was shorter in patients with stroke (1.74+/-0.84 s) than in controls (2.68+/-1.65 s, p=0.028). There was no difference between patients and controls in esophageal residue. In conclusion, patients with stroke and able to feed orally may have alterations in the esophageal transit of a liquid bolus.     

Effects of body position and bolus consistency on the manometric parameters and coordination of the upper esophageal sphincter and pharynx

The development of a solid-state intraluminal sphincter transducer has alleviated many of the problems associated with manometric studies of the upper esophageal sphincter (UES) and pharynx (P). We used this technology to study the effect of position (upright vs. supine) on resting UES pressures and the pressure dynamics of the UES/P complex during both wet and dry swallows in 11 normal volunteers and the effects of foods of different consistencies on the UES/P swallow dynamics in 10 normal volunteers. The UES/P coordination parameters were defined as the 15 time intervals that can be measured between any 2 of 6 pertinent points: the beginning, peak, and end of the pharyngeal contraction and the beginning, nadir, and end of the UES relaxation. Data from both the circumferential transducer used to measure sphincter pressures and a standard microtransducer used to measure pharyngeal pressures were collected on-line by an Apple IIe microcomputer and analyzed by programs written in our laboratory. Significant changes in swallow coordination were measured between upright and supine swallows of the same bolus size, between wet and dry swallows in the same position, and among foods of varying consistencies. Resting UES pressure was unchanged by position and pharyngeal contraction pressure was unchanged by bolus size or consistency.     

Timing of Pharyngeal and Upper Esophageal Sphincter Pressures as a Function of Normal and Effortful Swallowing in Young Healthy Adults

The effect of effortful swallow on pharyngeal pressure and UES relaxation onsets and durations was examined. Eighteen adults, nine males and nine females (mean age = 27.9 yr), participated. Timing of pharyngeal pressure and onset and duration of UES relaxation were measured across ten trials of normal and ten trials of effortful swallows. Results revealed that manometric timing measurements are consistent across trials. The first and second statistical analyses investigated the pharyngeal pressure and UES relaxation onsets and durations, respectively. Both analyses identified a significant interaction of swallow type (i.e., effortful vs. normal) by manometric sensor location (p < 0.05). Across normal and effortful swallows, UES relaxation preceded pharyngeal pressure onsets, yet the rate of change (or degree of delay) varied across the sensors. Furthermore, the effortful swallow elicited longer pharyngeal pressure and UES relaxation durations, yet the pressure duration measured in the upper pharynx was significantly longer than that measured lower in the pharynx. These findings offer insight as to the potential positive and negative influence of the effortful swallow on pharyngeal timing.     

Timing of videofluoroscopic,manometric events,and bolus transit during the oral and pharyngeal phases of swallowing

The aims of this study were to evaluate and quantify the timing of events associated with the oral and pharyngeal phases of liquid swallows. For this purpose, we recorded 0–20 ml barium swallows in three groups of volunteers using videoradiographic, electromyographic, and manometric methods. The study findings indicated that a leading complex of tongue tip and tongue base movement as well as onset of superior hyoid movement and mylohyoid myoelectric activity occurred in a tight temporal relationship at the inception of swallowing. Two distinct general types of normal swallows were observed. The common “incisor-type” swallow began with the bolus positioned on the tongue with the tongue tip pressed against the upper incisors and maxillary alveolar ridge. At the onset of the “dipper-type” swallow the bolus was located beneath the anterior tongue and the tongue tip scooped the bolus to a supralingual location. Beginning with tongue-tip peristaltic movement at the upper incisors, the two swallow types were identical. Swallow events that occurred after lingual peristaltic movement at the maxillary incisors showed a volume-dependent forward migration in time that led to earlier movement of the hyoid and larynx as well as earlier opening of the upper esophageal sphincter in order to receive the large boluses that arrived sooner in the pharynx during the swallow sequence than did smaller boluses. The study findings indicated that timing of swallow events should be considered in reference to both swallow type and bolus volume. The findings also indicated an important distinction between peristaltic transit and bolus clearance.     

The Prediction of Persistent Dysphagia Beyond Six Months After Stroke

The purpose of this study was to identify the videofluoroscopic prognostic factors that affect the recovery of swallowing function at an early stage after stroke and to make a tool for predicting the long-term prognosis. Eighty-three poststroke patients were selected prospectively. These patients had all undergone videofluoroscopic swallowing studies at an average of 40 days after stroke onset and were followed up for over six months. Prognostic factors were determined by logistic regression analysis between the baseline videofluoroscopic findings and aspiration over six months (p < 0.05). A videofluoroscopic dysphagia scale (VDS) with a sum of 100 was made according to the odds ratios of prognostic factors. The validity of the scale was evaluated by using a receiver operating characteristic curve. The VDS was compiled using the following 14 items: lip closure, bolus formation, mastication, apraxia, tongue-to-palate contact, premature bolus loss, oral transit time, triggering of pharyngeal swallow, vallecular residue, laryngeal elevation, pyriform sinus residue, coating of pharyngeal wall, pharyngeal transit time, and aspiration. At a scale cutoff value of 47, the sensitivity was 0.91 and the specificity was 0.92. The VDS was developed to be used as an objective and quantifiable predictor of long-term persistent dysphagia after stroke.