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.     

Upper esophageal sphincter opening and modulation during swallowing

Studies were done on 8 normal subjects with synchronized videofluoroscopy and manometry to facilitate a biomechanical analysis of upper esophageal sphincter opening and volume-dependent modulation during swallowing. Movements of the hyoid and larynx, dimensions of sphincter opening, and intraluminal sphincter pressure were determined at 1/30th-s intervals during swallows of 1, 5, 10, and 20 ml of liquid barium. Our analysis subdivided upper esophageal sphincter activity during swallowing into five phases: (a) relaxation, (b) opening, (c) distention, (d) collapse, and (e) closure. Sphincter relaxation occurred during laryngeal elevation and preceded opening by a mean period of 0.1 s. Opening occurred as the sphincter was pulled apart via muscular attachments to the hyoid such that the hyoid coordinates at which sphincter opening and closing occurred were constant among bolus volumes. Sphincter distention after opening was modulated by intrabolus pressures rather than graded hyoid movement. The generation of intrabolus pressure coincided with the posterior thrust of the tongue that culminated in pharyngeal wall contact and the initiation of pharyngeal peristalsis. Larger volume swallows were associated with greater intrabolus pressure and increased bolus head velocity. The duration of sphincter opening increased in conjunction with a prolongation of the anterior-superior excursion of the hyoid and a delay in the onset of pharyngeal peristalsis (the event that determined the timing of sphincter closure). We conclude that transsphincteric transport of increasing swallow bolus volumes is accomplished by modulating sphincter diameter, opening interval, and flow rate (reflected by bolus head velocity). Furthermore, upper esophageal sphincter opening is an active mechanical event rather than simply a consequence of cricopharyngeal relaxation.     

Pharyngeal (Zenker's) diverticulum is a disorder of upper esophageal sphincter opening.

Pharyngeal coordination, sphincter opening, and flow pressures during swallowing were investigated in patients with pharyngeal (Zenker's) diverticula. Fourteen patients with diverticula and 9 healthy age-matched controls were studied using simultaneous videoradiography and manometry. Pharyngeal and upper esophageal sphincter pressures were recorded by a perfused side hole/sleeve assembly. Temporal relationships among swallowing events, extent of sphincter opening during swallowing, and intrabolus pressure during bolus passage across the sphincter were measured. The timing among pharyngeal contraction and sphincter relaxation, opening, and closure did not differ between patients and controls. Sphincter opening was significantly reduced in patients compared with controls in sagittal (P = 0.0003) and transverse (P = 0.005) planes. Manometric sphincter relaxation was normal in patients. Intrabolus pressure was significantly greater in patients than in controls (P = 0.001). It is concluded that Zenker's diverticulum is a disorder of diminished upper esophageal sphincter opening that is not caused by pharyngosphincteric incoordination or failed sphincter relaxation. Incomplete sphincter opening is likely to cause dysphagia. Increased hypopharyngeal pressures during swallowing are probably important in the pathogenesis of the diverticulum.     

Videofluorographic Study of Swallowing in Parkinson's Disease

We studied 16 patients with Parkinson's disease (PD) with dysphagia and 8 young and 7 elderly normal controls videofluorographically to evaluate the nature of swallowing disorders in PD patients. In 13 patients, abnormal findings in the oral phase were residue on the tongue or residue in the anterior and lateral sulci, repeated pumping tongue motion, uncontrolled bolus or premature loss of liquid, and piecemeal deglutition. Thirteen patients showed abnormal findings in the pharyngeal phase, including vallecular residue after swallow, residue in pyriform sinuses, and delayed onset of laryngeal elevation. Ten of these patients also showed abnormal findings in both the oral and pharyngeal phases. Aspiration was seen in 9 patients. The oral transit duration was significantly longer in the patients with and without aspiration than in the control subjects. The stage transition duration, pharyngeal transit duration, duration of the upper esophageal sphincter (UES) opening, and total swallow duration were significantly longer in the patients with and without aspiration than in the young controls, but were not longer than in the elderly controls. These durational changes in the pharyngeal phase of swallowing were similar to those in the elderly controls. The findings suggest that the disturbed motility in the oral phase of swallowing may be due to bradykinesia. Although PD patients with dysphagia evince a variety of swallowing abnormalities, the duration of pharyngeal swallowing may remain within the age-related range until the symptoms worsen.     

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.     

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.     

Swallowing Physiology of Toddlers with Long-Term Tracheostomies: A Preliminary Study

This study investigated the swallowing physiology of toddler-aged patients with long-term tracheostomies. Structural movements and motility of the pharyngeal stage of swallowing were studied in four toddlers ranging in age from 1:2 (years:months) to 2:9 with long-term tracheostomies. A patient aged 1:2 years with no tracheostomy served as a toddler model for comparison. Videofluoroscopic recordings of the patients' liquid and puree bolus swallows were analyzed for a) onset times for pharyngeal stage events, laryngeal vestibule closure, and tracheostomy tube movement; b) timeliness of swallow response initiation; and c) pharyngeal transport function. Results found differences in timing of pharyngeal stage movements between the tracheostomized patients and the patient with no tracheostomy. Laryngeal vestibule closure occurred before or within the same 0.033-s video frame as onset of upper esophageal sphincter (UES) opening in the patient with no tracheostomy, but occurred 0.033–.099 s after onset of UES opening in the tracheostomized patients. The time line required to close the laryngeal vestibule once the arytenoids began their anterior movement was longer in the tracheostomized patients than in the patient with no tracheostomy and was associated with laryngeal penetration. The patient with no tracheostomy displayed superior excursion of the arytenoid and epiglottis during the swallowing; the tracheostomized patients did not. No association was found between onset of tracheostomy tube movement and laryngeal vestibule closure. Delayed swallow response initiation was observed across tracheostomized patients at a mean frequency of 45% with associated penetration. Pharyngeal dysmotility was not observed. Findings supported the concept that long-term tracheostomy in toddler-aged patients affects swallowing physiology.     

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.     

Dysphagia following Anterior Cervical Spine Surgery

Although previous reports have identified dysphagia as a potential complication of anterior cervical spine surgery (ACSS), current understanding of the nature and etiologies of ACSS-related dysphagia remains limited. The present study was undertaken to describe the patterns of dysphagia that may occur following ACSS. Thirteen patients who exhibited new-onset dysphagia following ACSS were studied retrospectively by means of chart review and videofluoroscopic swallow study analysis. Results indicated that a variety of swallowing impairments occurred following ACSS. In 2 patients, prevertebral soft tissue swelling near the surgical site, deficient posterior pharyngeal wall movement, and impaired upper esophageal sphincter opening were the most salient videofluoroscopic findings. In another 5 patients, the pharyngeal phase of swallowing was absent or very weak, with resulting aspiration in 3 cases. In contrast, an additional 4 patients exhibited deficits primarily of the oral preparatory and oral stages of swallowing including deficient bolus formation and reduced tongue propulsive action. Finally, 2 patients exhibited impaired oral preparatory and oral phases, a weak pharyngeal swallow, as well as prevertebral swelling. Thus, a variety of swallowing deficits, due possibly to neurological and/or soft tissue injuries, may occur following ACSS.     

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.     

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.     

Manofluorographic analysis of swallowing in the elderly

This study examined the effect of aging on the mechanisms of swallowing by comparing 16 elderly subjects (80 years±5) with 20 healthy volunteers. Manofluorography was used to obtain quantitative and qualitative data of the pharyngeal swallow. Aging is associated with a significant decrease in the level of negative pressure resulting from the opening of the upper esophageal sphincter and with a substantial number of incomplete relaxations of the sphincter. In addition, several qualitative changes were noted.     

Effects of Nasogastric Tubes on the Young, Normal Swallowing Mechanism

The present study aimed to investigate the effects of different-sized nasogastric tubes on swallowing speed and function in 10 young normal volunteers. Using X-ray visualization, liquid barium swallows were recorded on video (videofluoroscopy) under three experimental conditions: no nasogastric tube, fine-bore nasogastric tube, and wide-bore nasogastric tube. Nasogastric tubes slowed swallowing but did not alter swallowing function, namely bolus transit and clearance, and airway protection. The presence of a wide-bore nasogastric tube caused significant duration changes in several swallowing measures, namely duration of stage transition, duration of pharyngeal response, duration of pharyngeal transit, and duration of upper esophageal sphincter opening. Similar trends were seen for the fine-bore tube. The implications for nonoral feeding of patients with swallowing disorders are discussed.     

Facioscapulohumeral Muscular Dystrophy: A Radiologic and Manometric Study of the Pharynx and Esophagus

Facioscapulohumeral muscular dystrophy (FSHD) is not a recognized neuromuscular cause of dysphagia. However, a study of pharyngoesophageal function in FSHD has not been performed or reported. The aim of this study was to ascertain by relatively noninvasive techniques whether the dystrophic muscle disease that underlies FSHD involves the pharyngeal and/or the esophageal striated and smooth muscles. We used conventional cineradiography and intraluminal esophageal manometry on separate occasions to study pharyngeal and esophageal function in 20 patients with FSHD at various stages of disease, with or without complaints of deglutition. Age- and sex-matched control data were used for comparison of the manometric component of the study. Twelve men and eight women with FSHD were studied. The mean patient age was 38.1 years (41.9 years for controls), and the age range was 19-61 years (22-55 years for controls). The mean disease duration was 16.7 years (range = 4-39 years).Five patients admitted to having intermittent oropharyngeal dysphagia (difficulty to initiate swallowing, cough after swallowing, sensation of food stuck in throat, or nasal regurgitation), and three patients admitted to intermittent esophageal dysphagia (difficulty swallowing both liquids and solids). Chest roentgengrams showed a hiatal hernia in four patients, but no active cardiopulmonary disease. Abnormal instrumental results were documented in eight patients: Cineradiography detected ineffectual pharyngeal contractions (2 patients), pharyngeal diverticula but normal pharyngeal motility (2 patients), and decreased cricopharyngeal and upper esophageal relaxation (2 patients). The mean manometric pressure of the patient group was not significantly different from the control data. However, manometry detected motility abnormalities that were not reflected in the mean data and included increased lower esophageal sphincter resting pressure with normal or abnormal relaxation (2 patients) and inconsistent, high-amplitude, long-duration, primary peristaltic contractions (1 patient). Patients with FSHD did not spontaneously volunteer intermittent complaints of deglutition. This study did not definitely establish that the cause of abnormal pharyngeal and cervical esophageal function was related to the dystrophic process that underlies FSHD. Any esophageal dysmotility was nonspecific and insignificant and was caused by an undetermined, probably neuropathic, process unrelated to the muscular dystrophy.     

Predictors of Outcome following Cricopharyngeal Disruption for Pharyngeal Dysphagia

The indications for, and predictors of outcome following cricopharyngeal disruption in pharyngeal dysphagia are not clearly defined. Our purpose was to examine the symptomatic response to cricopharyngeal disruption, by either myotomy or dilatation, in patients with oral-pharyngeal dysphagia and to determine pretreatment manometric or radiographic predictors of outcome. Using simultaneous pharyngeal videoradiography and manometry, we studied 20 patients with pharyngeal dysphagia prior to cricopharyngeal diltation (n = 11) or myotomy (n = 8), and 23 healthy controls. We measured peak pharyngeal pressure, hypopharyngeal intrabolus pressure, upper esophageal sphincter diameter, and coordination. Response rate to sphincter disruption was 65%. The extent of sphincter opening was significantly reduced in patients compared with controls (p= 0.004), but impaired sphincter opening was not a predictor of outcome. Increased hypopharyngeal intrabolus pressures (>19 mmHg for 10 ml bolus; >31 mmHg for 20 ml bolus) was a significant predictor of outcome (p= 0.01). Neither peak pharyngeal pressure nor incoordination were predictors of outcome. In pharyngeal dysphagia, hypopharyngeal intrabolus pressure, and not peak pharyngeal pressure, is a predictor of response to cricopharyngeal disruption. The relationship between intrabolus pressure and impaired sphincter opening is an indirect measure of sphincter compliance which helps predict therapeutic response.     

Functional Imaging of the Pharynx Using Electron Beam Tomography

Due to long scan times it was impossible to make dynamic swallowing imaging using computer tomography (CT) of the third or fourth generation. This study evaluates whether electron beam tomography with scan times of 100 ms enables a more detailed dynamic imaging of swallowing disorders. Examination using electron beam tomography was done in three planes: (1) Passavant's cushion (n = 6), (2) thyrohyoid membrane (n = 9), and (3) upper esophageal sphincter (n = 5). The technique is discussed here in detail and documented with figures of the plane before swallowing as well as the intradeglutitive reachend plane. This study shows that electron beam tomography enables dynamic imaging of pharyngeal deglutition in transverse planes and can give useful additional information to the videofluorographic or kinematographic swallowing examination, which remain the gold standard in the functional evaluation of swallowing disorders.     

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.     

Oropharyngeal and esophageal function in scleroderma

Fifty-one patients with systemic sclerosis (scleroderma) underwent videofluoroscopy during barium swallow to evaluate the incidence of oropharyngeal deglutition abnormalities and to correlate the radiologic patterns of esophageal motility abnormalities with patients' clinical features. Thirteen patients (26%) showed swallowing dysfunction, (e.g., oral leakage, retention, penetration, mild or moderate aspiration, and upper esophageal sphincter incoordination). These dysfunctions were more severe in patients with prominent esophageal dysmotility. Normal esophageal motility was not associated with swallowing alterations. Patients with an oropharyngeal disorder had a higher incidence of pulmonary disease. The clinical picture of the above-mentioned 13 patients was more severe, based on the duration of Raynaud's phenomenon and duration of skin sclerosis. Patients with primary Raynaud's phenomenon had no oral or esophageal abnormalities. The esophageal phase of swallowing was abnormal in 80% of the patients with scleroderma. Esophageal dysfunction, therefore, seems to be frequent in the early stages of the disease. However, patients with advanced or extensive disease may have normal esophageal function.     

Timing of Events in Normal Swallowing: A Videofluoroscopic Study

Dynamic videofluoroscopic swallow studies were performed on 60 normal adult volunteers to establish normative data for clinically useful timing measures. The relation of swallowing gesture timing to the timing of actual bolus transit was of particular interest because it provides insight into the physiology of larger bolus volume accommodation. Parameters evaluated include the timing of bolus pharyngeal transit, soft palate elevation, aryepiglottic fold elevation and supraglottic closure, arrival of the bolus in the vallecula, hyoid bone displacement onset and duration, arrival of the bolus at the pharyngoesophageal sphincter, maximum pharyngeal constriction, and pharyngoesophageal sphincter opening. These parameters represent events required for normal deglutition, can be used to identify abnormalities in dysphagic patients, and provide a basis for comparison of swallowing performance both within and between patients. In addition, our experience has shown them to be reliably obtained. Other investigators have reported some of the measurements. However, to our knowledge, normative data for timing of aryepiglottic fold elevation, soft palate elevation and closure, and maximum pharyngeal constriction have not been described. Other measures included in the present study may provide alternatives when conventional measures cannot be obtained in selected patients. The relevance and clinical utility of new and alternative measures, in particular, are discussed.     

Dysphagia in a patient with lateral medullary syndrome: insight into the central control of swallowing

BACKGROUND & AIMS: Central control of swallowing is regulated by a central pattern generator (CPG) positioned dorsally in the solitary tract nucleus and neighboring medullary reticular formation. The CPG serially activates the cranial nerve motor neurons, including the nucleus ambiguus and vagal dorsal motor nucleus, which then innervate the muscles of deglutition. This case provides insight into the central control of swallowing. METHODS: A 65-year-old man with a right superior lateral medullary syndrome presented with a constellation of symptoms, including dysphagia. The swallow was characterized using videofluoroscopy and esophageal motility and the results were compared with magnetic resonance imaging (MRI) findings. RESULTS: Videofluoroscopy showed intact lingual propulsion and volitional movements of the larynx. Distal pharyngeal peristalsis was absent, and the bolus did not pass the upper esophageal sphincter. Manometry showed proximal pharyngeal contraction and normal peristaltic activity in the lower esophagus (smooth muscle), but motor activity of the upper esophageal sphincter and proximal esophagus (striated muscle) was absent. MRI showed a lesion of the dorsal medulla. CONCLUSIONS: These findings are compatible with a specific lesion of the connections from a programming CPG in the solitary tract nucleus to nucleus ambiguus neurons, which supply the distal pharynx, upper esophageal sphincter, and proximal esophagus. There is functional preservation of the CPG control center in the solitary tract nucleus and of the vagal dorsal motor nucleus neurons innervating the smooth muscle esophagus.