Effect of head position on the dynamics of the upper esophageal sphincter and pharynx

Due to limitations in available technology it has been difficult to obtain data on upper esophageal sphincter (UES) and pharyngeal (P) function under varying physiologic conditions. We used a manometry system with solid-state intraluminal transducers, including a circumferential sphincter transducer, and computer analysis to measure pressure changes in UES and P during wet (5 ml H₂O) swallows as the head was moved through a 75 degree arc in nine normal volunteers. UES residual pressure increased markedly and duration of UES relaxation decreased with increasing head extension. Similar decreases were also seen with time between P peak and both UES nadir and UES end. There were no changes in either pharyngeal peak pressures or the duration of the pharyngeal contraction. Head extension produces major changes in UES relaxation and UES/P coordination. These effects may be clinically important when feeding neurologically impaired patients.     

Upper esophageal sphincter function during deglutition

Upper esophageal sphincter function was investigated during swallows of graded volumes in 8 normal volunteers. Concurrent recordings of video-fluoroscopic and manometric studies were obtained and correlated with each other by means of a videotimer. Maximal upper esophageal sphincter (UES) pressure was typically located 1.5 cm distal to the air-tissue interface between the hypopharynx and the proximal margin of the sphincter. The region in which UES pressure was greater than or equal to 50% maximal averaged 1.0 cm in length. Thus, the physiologic high-pressure zone of the UES corresponds in size and location to that of the cricopharyngeus muscle. Fluoroscopic analysis of sphincter movement indicated that the sphincter high-pressure zone moved 2.0-2.5 cm orally during swallowing and that the magnitude of the orad movement was directly related to the volume of barium swallowed. The maximal anterior-posterior diameter of sphincter opening during a swallow ranged from 0.9 to 1.5 cm and was also directly related to the volume swallowed. The intervals of UES opening and relaxation increased significantly with increasing bolus volume; the duration of UES relaxation ranged from a mean of 0.37 s for dry swallows to 0.65 s for 20-ml swallows. Thus, the dynamics of UES function during deglutition are dependent upon the volume of the swallowed bolus. Larger bolus volumes are accommodated by both an increased diameter of sphincter opening and by prolongation of the interval of sphincter relaxation. Analysis of the timing of other reference points within the pharyngeal swallow sequence indicated that as the manometric interval of UES relaxation increased, the period of laryngeal elevation was prolonged, the UES relaxed earlier and contracted later, and the interval between the onset of laryngeal elevation and hypopharyngeal contraction increased.     

Simultaneous videoradiography and pharyngeal solid state manometry (videomanometry) in 25 nondysphagic volunteers

Recent technological advances in manometry, including solid state transducers and computerized analysis, allows for reliable interpretation of intraluminal pharyngeal pressures. Simultaneous videoradiography (barium swallow) provides fluoroscopic control of the manometric sensors (videomanometry), thereby eliminating the uncertainty of sensor dislocation during laryngeal elevation. This is the first study describing normal manometric parameters in videomanometry during barium swallow. Seven manometric parameters and six videoradiographic parameters were analyzed. We included 25 nondysphagic volunteers with normal videoradiographic parameters in the study. The examination was performed in an upright physiologic position during 10-ml barium and dry swallows. Mean resting pressure in the upper esophageal sphincter was 89.6±32.6 (±2 SD) mmHg. Mean residual pressure during relaxation of the upper esophageal sphincter was 7.2±8.0 (±2 SD) mmHg during barium swallow and 3.8±6.2 (±2 SD) mmHg during dry swallow. The mean duration of upper esophageal sphincter relaxation was 601±248 (±2 SD) msec. The mean peristaltic contraction of the upper esophageal sphincter was 253.8±142.8 (±2 SD) mmHg. Fourteen (56%) of the 25 had a measurable intrabolus pressure (mean 33.2±17.3 mmHg) at the level of the inferior pharyngeal constrictor. A specific finding was discovered when the epiglottis tilts down hitting the manometric sensor. This epiglottic tilt was identified in 7 subjects (28%) and caused pressures of around 600 mmHg. A standardized manometric technique is important in videomanometry, and normal values as described in this study are essential in clinical use.     

Pharyngeal/upper esophageal sphincter pressure dynamics in humans

Extensive physiological studies of swallowing have been carried out in laboratory animals; however, similar studies in humans have been limited by available technology. In this study we describe the use of a solid-state circumferential sphincter transducer to define manometric characteristics of the human pharynx and upper esophageal sphincter (UES). Effects of pharmacologic agents and thermal stimulation are also described. We studied nine normal volunteers on three separate days. All studies were done in the upright position and consisted of a station pull-through of the UES and six wet swallows with the sphincter transducer in the most proximal segment of the UES and a posteriorly oriented single transducer 5 cm proximal in the pharynx. Baseline studies preceded all drug studies. Effects of bethanechol were studied on day 1, cold stimulation and benzonatate on day 2, edrophonium and atropine on day 3. The UES resting pressure showed large intrasubject day-to-day variations; however, mean values did not differ. There were no effects on UES relaxation or swallow coordination with any of the pharmacologic agents, although benzonatate produced multiple pharyngeal contractions.     

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     

Influence of the viscosity of the swallowed food bolus on the motility of the pharynx

In 9 young men, healthy volunteers, we studied the effect of dry swallows, liquid and paste swallows on the pharyngeal motility. The viscosities of liquids and past were 200 centipoise (cP), 300 cP and 60000 cP, respectively. The bolus volume was 10 ml. For pharyngeal manometry we used two strain-gauge manometric probes taped together, so that a total of six transducers were staggered at 1.5 cm intervals. After its passage through the nose, the assembly was positioned so that all its transducers faced posteriorly, and manometric activity was recorded from oropharynx, hypopharynx and upper esophageal sphincter (UES). We also recorded infra-hyoid electromiographic activity. The amplitude and duration of the oropharyngeal and hypopharyngeal peristaltic pressure complex were not changed by the different boluses. The velocity of peristaltism propagation between oropharynx and UES was slower for paste than for liquids or dry swallows. The increased of viscosity was associated with longer duration of UES relaxation, and greater intrabolus pressure in hypopharynx and UES. The infra-hyoid electromiographic activity was longer for paste than for liquids or dry swallows. These findings suggest that pharyngeal motility is affected by the characteristics of the swallowed bolus.     

The Effects of Age, Sex, and Smoking on Normal Pharyngoesophageal Motility

Previous reports of normal pharyngoesophageal motility have described normal ranges in small numbers of young adults. In this study, the results of upper esophageal sphincter (UES) manometry with a microtransducer assembly in 67 healthy volunteers aged 17-77 yr have been analyzed for possible effects of age, sex, and cigarette smoking. Older subjects were found to have only marginally lower UES tonic pressures, but markedly elevated pharyngeal contraction pressures. Increasing age was associated with a reduction in duration of upper esophageal contractions and, for bread swallows, an increase in pharyngoesophageal wave velocity which may represent compensatory mechanisms for airway protection. Male subjects showed greater UES axial asymmetry than females, perhaps due to sex differences in laryngeal anatomy, whereas females had greater UES wet swallow after-contraction pressures which may be relevant to the generation of globus sensation. All results were independent of cigarette smoking. We conclude that normal values obtained in small numbers of young adults form an inadequate basis for the interpretation of UES tonic and pharyngeal contraction pressures, which are reported to be abnormal in older patients with dysphagia, and that manometric investigation of dysphagic patients requires the analysis of multiple parameters of dynamic pharyngoesophageal function.     

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.     

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.     

Pharyngeal clearance during swallowing: a combined manometric and videofluoroscopic study.

The deglutitive pharyngeal contraction was analyzed using simultaneous videofluoroscopic and manometric studies of eight volunteers. Anterior, posterior, and longitudinal movements of the pharyngeal surfaces, relative to the cervical vertebrae, were measured during swallows of 5 and 10 mL of liquid barium. Profound pharyngeal shortening during bolus transit through the pharynx eliminated access to the larynx and elevated the upper esophageal sphincter to within 1.5 cm of the retrolingual pharynx. Bolus head movement through the pharynx preceded the propagated pharyngeal contraction and registered manometrically as a slight intrabolus pressure before the major pressure complex. Contraction in the horizontal plane began after bolus head transit and culminated with stripping of the bolus tail through the pharynx. Prolonged upper sphincter opening with the larger-volume swallows resulted from a delayed onset rather than altered propagation of the horizontal pharyngeal contraction. It is concluded that the propagated pharyngeal contraction facilitates pharyngeal clearance but has a minimal role in the process of bolus propulsion during swallowing. The propagated contraction works in concert with profound pharyngeal shortening to minimize hypopharyngeal residue after a swallow.     

Aging-related alterations in human upper esophageal sphincter function

Recent improvements in manometric catheters have made measurement of pharyngeal (P) and upper esophageal sphincter (UES) swallowing mechanics more reliable. Few studies have attempted to evaluate the effect of normal aging on P and UES mechanics. Pharyngeal and upper esophageal sphincter dynamics were studied in 10 healthy elderly adults (age greater than 60; range 62-79 yr) and 10 younger adults (age less than 60; range 24-59 yr). A solid-state intraluminal transducer system was used with a proximal unidirectional Konigsberg microtransducer and a circumferential (sphincter) transducer located 5 cm distally. Mean resting UES pressure was significantly (p less than 0.05) lower in the elderly than in the younger subjects (52 +/- 5 vs 72 +/- 6 (SE)) mm Hg. A significant inverse relation (R = -0.54; p less than 0.02) was found between age and resting UES pressure. Time from peak of pharyngeal contraction to UES nadir was significantly (p less than 0.05) shortened in the healthy elderly vs younger controls (10 +/- 30 vs 90 +/- 20 ms) during dry swallows. Our studies indicate that aging is associated with lower resting UES pressure and delayed UES relaxation, relative to the pharyngeal peak.     

Effects of Bolus Volume on Pharyngeal Contact Pressure During Normal Swallowing

This cross-sectional study investigated the effect of bolus volume on contact pressure within the pharynx and upper esophageal sphincter (UES). Three solid-state manometric pressure sensors were placed transnasally into the pharynx and the proximal esophagus of 40 participants (gender equally represented and between the ages of 20 and 45 years). Participants completed five repetitions each of three swallowing conditions: 5-, 10-, and 20-ml water bolus swallows. Repeated-measures ANOVA revealed no significant differences in the amplitude of pharyngeal contact pressure between the three swallowing conditions (sensor 1: p = 0.627, sensor 2: p = 0.764). Similarly, for durational measures nonsignificant main effects were found at both sensor 1 (p = 0.436) and sensor 2 (p = 0.350). Significant differences were found in UES pressure between the three conditions of bolus swallows (p = 0.000), with negative pressure in the UES inversely proportionate to bolus volume. However, durational measures of UES relaxation pressure were not significantly different between all conditions (p = 0.473). This study demonstrates no significant pressure differences of amplitude and duration between swallowing conditions in the pharynx. At the level of the UES, smaller boluses generated greater negative pressure.     

Modulation of esophageal peristalsis by alterations of body position

Previous studies have demonstrated that nonviscous liquids traverse the esophagus more rapidly with the subject in the upright rather than the supine position. Conversely, similar studies have shown that viscous liquids traverse the esophagus at similar rates for both upright and supine positions. Our purpose was to define the motor correlates of these differing responses. Six normal volunteers were studied with an infused catheter system incorpoating a Dent sleeve for monitoring lower esophageal sphincter pressure. The subjects were given a series of swallows of a water and a viscous (52 centipoise) bolus in both the supine and upright positions. In the upright position, the water bolus caused an increased velocity of propagation in the proximal esophageal segment that was associated with a shortening of lower esophageal sphincter relaxation time and reductions in amplitude and duration of contraction. No significant changes in the peristaltic wave were noted with the viscous bolus during alterations of body position. We conclude that the more rapid transit of a nonviscous water bolus through the esophagus in the upright position is reflected in specific alterations of esophageal peristaltic parameters. The possible mechanisms for these differing responses are discussed.     

Structural Displacements in Normal Swallowing: A Videofluoroscopic Study

Dynamic videofluoroscopic swallow studies were performed on 60 normal adult volunteers to establish normative data for displacement of upper aerodigestive tract structures during deglutition. Variables evaluated included hyoid bone displacement, larynx-to-hyoid bone approximation, pharyngeal constriction, and the extent of pharyngoesophageal sphincter (PES) opening during liquid swallows of 1, 3, and 20 cc. Results showed direct relationships between bolus size and hyoid displacement, between bolus size and PES opening, and between bolus size and pharyngeal constriction. Only hyoid-to-larynx approximation remained unchanged across bolus sizes. Sex differences were noted for all variables except PES opening. Reliability for most measurement variables was excellent. To our knowledge, normative data for pharyngeal constriction and larynx-to-hyoid approximation have not previously been described.     

Event Sequence Variability in Healthy Swallowing: Building on Previous Findings

This study builds on previous work by Kendall, Leonard, and McKenzie, which investigated event sequence variability for 12 paired events during swallowing by healthy volunteers. They identified four event pairs that always occurred in a stereotyped order and a most common occurring overall order of events during swallowing. In the current study, we investigated overall event sequencing and the same four paired events in a sample of swallows by healthy young (under 45 years old) volunteers. Data were collected during a 16-swallow lateral videofluoroscopy protocol, which included manipulations of bolus volume, barium density, bolus viscosity, and swallow cueing. Our results agreed with previous findings that variable event sequencing is found in healthy swallowing, and, in regard to obligatory sequencing of two paired events, movement of the arytenoids toward the base of the epiglottis begins prior to upper esophageal sphincter (UES) opening and maximum hyolaryngeal approximation occurs after UES opening. However, our data failed to replicate the previous findings that there is obligatory sequencing of maximum pharyngeal constriction after maximal UES distension and the UES opens before bolus arrival at the UES. The most common observed overall event sequence reported by Kendall et al. was observed in only 4/293 swallows in our dataset. Manipulations of bolus volume, bolus viscosity, barium concentration, swallow cueing, and swallow repetitions could not completely account for the differences observed between the two studies.     

Dysphagia after pharyngolaryngeal cancer surgery. Part I: Pathophysiology of postsurgical deglutition

Eighty-one patients were examined after laryngopharyngeal cancer surgery with a sequential computer manometry system using 4-channel-pressure probes. The general swallowing coordination is neither a matter of the oropharyngeal pressure thrust nor of the pharyngeal transit time, but mainly depends on swallowing initiation. The points of interest are both the pharyngeal inlet and outlet. The topographic correlates are the base of the tongue and the upper esophageal sphincter (UES). Resections of the base of the tongue lead to a decrease of volume available for pressure generation, thus reducing the tongue driving force. The swallowing reflex is uncoordinated resulting in dyskinesia of the UES. Compensation may be achieved with a stronger oropharyngeal thrust and/or repeated swallows. Distal resections alter the pharyngoesophageal segment so that a functional obstruction results, combined with lower pressure amplitudes in the hypopharynx, reducing the pressure gradient necessary for bolus flow. This increasing resistance can be overcome by higher propulsive forces in the base of the tongue region. In case of additional lingual defects, deglutition is subject to decompensation, highlighting the major role of the tongue as a pressure generator for bolus passage.     

Effect of Age and Bolus Variables on the Coordination of the Glottis and Upper Esophageal Sphincter during Swallowing

We studied 1) the effect of age and bolus variables on a) the coordination of deglutitive vocal cord adduction and upper esophageal sphincter (UES) relaxation and b) the duration of deglutitive vocal cord adduction; 2) the effect of the presence of a manometric catheter across the UES on the deglutitive glottal function; and 3) the temporal relationship between deglutitive vocal cord closure and swallow-induced apnea. We studied 10 young (23 ± 2 yr) and 10 healthy elderly (73 ± 2 yr) volunteers by concurrent videoendoscopy, UES manometry, respirography, and submental surface electromyography. In both groups the onset of vocal cord adduction preceded the onset of UES relaxation, deglutitive apnea, and submental electromyogram swallowing signal. In both groups, bolus volume and temperature did not have any significant effect on the duration of deglutitive vocal cord adduction. In both young and elderly volunteers, water swallows, compared with dry swallows, significantly shortened the interval between the onset of deglutitive vocal cord adduction and the onset of UES relaxation.
In conclusion, coordination between deglutitive glottal and UES function, as well as the duration of deglutitive vocal cord adduction, is preserved in the elderly. Bolus volume and temperature do not have a modulatory effect on the duration of vocal cord closure, but water swallow shortens the interval between the onset of glottal closure and UES relaxation. This shortened interval may contribute to the safety of the airway during swallowing of liquid volumes.     

Influence of everyday bolus consistencies in different body positions on high‐resolution esophageal pressure topography (HREPT) parameters

The standard protocol for esophageal manometry involves placing the patient in the supine position with head turned to left (supine head left [SHL]) while evaluating liquid bolus swallows. Routinely, semisolid or solid boluses are not evaluated. Currently, the daily American diet includes up to 40% solid or semisolid texture. Thus far, the data on the effect of different bolus on high‐resolution esophageal pressure topography (HREPT) parameters are scarce. This study aims to evaluate the effect of every day bolus consistencies in different body positions on HREPT variables. HREPT was performed on healthy volunteers with a modified protocol including liquid swallows in the SHL position followed by applesauce (semisolid), cracker (solid), and marshmallow (soft solid) in three different positions (SHL, sitting, and standing). A total of 38 healthy adult subjects (22 males and 16 females, median age = 27, and mean body mass index = 25) were evaluated. The resting upper esophageal sphincter pressure was significantly different while subjects swallowed crackers, applesauce, and marshmallows in most positions compared with liquid SHL (P < 0.05). The lower esophageal sphincter, contractile front velocity, and distal contractile integral pressures did not differ in all different consistencies compared with SHL. The integrated relaxation period was significantly higher with solid bolus compared with liquid bolus only in SHL position. The intrabolus pressure was significantly different with solid and soft solid boluses in all postures compared to liquid SHL. The American diet consistency affects upper esophageal sphincter pressure and partially integrated relaxation period and intrabolus pressure in various positions. Semisolid bolus swallows do not cause substantial pressure changes and are safe for evaluation and maintaining adequate caloric intake in patients with dysphagia who cannot tolerate solids.     

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.     

Radial and longitudinal asymmetry of human pharyngeal pressures during swallowing

Radial asymmetry of upper esophageal sphincter resting pressure has been previously described; however, neither radial nor longitudinal asymmetry of pharyngeal pressures has been demonstrated. The authors used a specially designed intraluminal transducer catheter (Konigsberg; Konigsberg Instruments, Pasadena, CA) with four solid-state transducers separated by 3 cm and oriented circumferentially at 90 degrees intervals to measure pharyngeal pressures. Two wet swallows at each 1-cm interval along the length of the pharynx were measured in 12 normal volunteers (10 male, 2 female; mean age, 38 years). Pressure data were collected on-line by an Apple IIe microcomputer (Apple Computer Inc., Cupertino, CA) at 100 Hz and analyzed for both radial and longitudinal asymmetry. Significant (P less than 0.05) longitudinal asymmetry was shown in all positions except right lateral. Radial asymmetry was present for the first 4 cm only, with anterior and posterior pressures significantly (P less than 0.05) higher than lateral pressures. It was concluded that pharyngeal pressure responses show both axial and longitudinal asymmetry in the distal pharynx. Awareness of transducer position and orientation is essential in the evaluation of pharyngeal pressures.