High-Resolution Manometry of Pharyngeal Swallow Pressure Events Associated with Effortful Swallow and the Mendelsohn Maneuver

Effortful swallow and the Mendelsohn maneuver are two common strategies to improve disordered swallowing. We used high-resolution manometry (HRM) to quantify the effects of these maneuvers on pressure and timing characteristics. Fourteen normal subjects swallowed multiple, 5-ml water boluses using three techniques: normal swallow, effortful swallow, and the Mendelsohn maneuver. Maximum pressure, rate, duration, area integral, and line integral were determined for the velopharynx and tongue base. Minimum pressure, duration of pressure-related change, duration of nadir pressure, maximum preopening and postclosure pressure, area integral, and line integral were recorded for the upper esophageal sphincter (UES). Area and line integrals of the velopharyngeal pressure curve significantly increased with the Mendelsohn maneuver; the line integral increased with the effortful swallow. Preopening UES pressure decreased significantly for the Mendelsohn, while postclosure pressure tended to increase insignificantly for both maneuvers. UES area and line integrals as well as nadir UES pressure duration increased with both maneuvers. Maneuver-dependent changes were observed primarily at the velopharynx and UES. These regions are critical to safe swallowing, as the velopharynx provides positive pressure at the bolus tail while the UES allows a bolus to enter the esophagus without risk of regurgitation. Integrals were more responsive than maximum pressure or duration and should be investigated further.     

Tongue Pressure During Swallowing in Adults with Down Syndrome and Its Relationship with Palatal Morphology

In individuals with Down syndrome, hypotonicity of the tongue and an underdeveloped maxilla may lead to poor oral motor coordination, which adversely affects the oral phase of swallowing. This study aimed to evaluate the characteristics of pressure produced by the tongue against the hard palate during swallowing in individuals with Down syndrome. In addition, the relationship between tongue pressure and palatal morphology was examined. We studied nine adults with Down syndrome and ten healthy adults as controls. Tongue pressure while swallowing 5 mL water was recorded by a sensor sheet system with five measuring points attached to the hard palate. Palatal length, depth, width, curvature, and slope were measured by three-dimensional digital maxillary imaging. The order of onset of tongue pressure on the median line of the hard palate was the same in all participants, except for three with Down syndrome. The duration and maximal magnitude of tongue pressure on the median line in nine participants with Down syndrome were significantly shorter and lower than those of controls. In participants with Down syndrome, significant positive correlations were observed between the duration of tongue pressure at the mid-median part of the hard palate and palatal depth and width, and between the duration and maximal magnitude of tongue pressure at the posterior-median part and palatal length. These findings suggest that impaired tongue activity, poor tongue control, and constrained tongue motion due to a short and narrow palate contribute to swallowing difficulty in individuals with Down syndrome.     

Pattern of Tongue Pressure on Hard Palate During Swallowing

Contact of the tongue against the hard palate plays an important role in swallowing. This study aimed to clarify the pattern of contact between the tongue and hard palate by analyzing tongue pressure produced in swallowing 15 ml of water by healthy subjects wearing an experimental palatal plate with seven pressure sensors. Tongue pressure was generated initially by close contact with the anteriomedian part of the hard palate, then with the circumferential part, and finally softly with the posteriomedian part. Tongue pressure reached a peak quickly, then decreased gradually before disappearing almost simultaneously at each measured part of the hard palate. Magnitude and duration were significantly larger in the anteriomedian part compared to the other six parts measured, and was significantly smaller in the posteriomedian part. No laterality was found in tongue pressure produced at the circumferential parts of the hard palate. Our findings indicate that the order of tongue contact against each part of the hard palate as well as duration and magnitude of tongue pressure are coordinated precisely during swallowing. These findings could aid assessment of the tongue movement of dysphagic patients during rehabilitation.     

Tongue Pressure Patterns During Water Swallowing

Bolus propulsion during the normal oral phase of swallowing is thought to be characterised by the sequential elevation of the front, middle, and posterior regions of the dorsum of the tongue. However, the coordinated orchestration of lingual movement is still poorly understood. This study examined how pressures generated by the tongue against the hard palate differed between three points along the midline of the tongue. Specifically, we tested three hypotheses: (1) that there are defined individual patterns of pressure change within the mouth during liquid swallowing; (2) that there are significant negative pressures generated at defined moments during normal swallowing; and, (3) that liquid swallowing is governed by the interplay of pressures generated in an anteroposterior direction in the mouth. Using a metal appliance described previously, we measured absolute pressures during water swallows in six healthy volunteers (4 male, 2 female) with an age range of 25–35 years. Participants performed three 10-ml water swallows from a small cup on five separate days, thus providing data for a total of 15 separate water swallows. There was a distinct pattern to the each of the pressure signals, and this pattern was preserved in the mean obtained when the data were pooled. Furthermore, raw signals from the same subjects presented consistent patterns at each of the five testing sessions. In all subjects, pressure at the anterior and hind palate tended to be negative relative to the preswallow value; at mid–palate, however, pressure changes were less consistent between individuals. When the pressure differences between the sites were calculated, we found that during the swallow a net negative pressure difference developed between anterior and mid-palate and a net positive pressure difference developed between mid-palate and hind palate. Large, rapid fluctuations in pressure occurred at all sites and these varied several-fold between subjects. When the brief sharp reduction in pressure that occurred early in each swallow was used to determine the sequence of events, we found that activity occurred first at the anterior of the palate followed by the mid-palate and then the hind palate. There was a considerably longer and more variable delay between the start of activity at the front of the palate than at the rear of the palate. To obtain an index of the “effort” involved in generating the pressures at each site regardless of direction (positive or negative), we obtained the product of the root mean square (RMS) pressure change during each swallow (kPa) and its duration (s). Overall, the most effort appears to have occurred at the front of the palate and the least at mid-palate. Our results also showed that some participants exerted a small amount of midline pressure when swallowing, while others used a relatively large amount of tongue pressure. We conclude that while tongue behaviour during swallowing follows a classical sequence of rapid shape changes intended to contain and then propel the bolus from the oral cavity to the pharynx, there is a large range of individual variability in how this process is accomplished.     

Involvement of Sensory Input from Anterior Teeth in Deglutitive Tongue Function

Swallowing is a reflex that receives sensory information from the peripheral nerves and from the cerebral cortex. The aim of the present study was to investigate whether the sensory input from anterior teeth affects the functional characteristics of tongue pressure applied against the hard palate during swallowing. Subjects were eight healthy volunteers. Tongue pressure against the hard palate during swallowing 10 ml of water was measured under two conditions: preanesthesia and postanesthesia of anterior teeth. The sensory deprivation of anterior teeth was performed by periodontal anesthesia. Tongue pressure was measured using a multiple tactile array sensor (MTAS) with eight sensor channels arranged in tandem. The duration of the tongue pressure production during swallowing was increased under periodontal anesthesia. In addition, the maximum tongue pressure and the pressure integral during swallowing were decreased under periodontal anesthesia, in particular at the anterior region of the palate. These findings indicate that sensory input from anterior teeth, including periodontal mechanoreceptor, affects the deglutitive tongue pressure and duration and provides peripheral feedback to modulate some aspects of the neurophysiologic control of deglutitive tongue movement.     

Relationship Between Tongue Base Region Pressures and Vallecular Clearance

Tongue base pressures have been thought to provide primary bolus clearance through the pharynx during swallowing. The relationship between bolus driving pressures and residue remaining in the valleculae after the swallow has not been defined. Thirty-seven dysphagic patients who were evaluated with both videofluoroscopy (VFSS) and high-resolution manometry (HRM) were identified within the University of Wisconsin Voice and Swallowing Outcomes database. Patients were categorized according to binary ratings of presence or absence of vallecular stasis as well as incomplete or complete tongue retraction on VFSS. Tongue base region pressures measured with HRM during saline swallows of 1 and 10 ml volumes were compared to ratings of vallecular stasis or tongue base retraction. No significant difference could be identified among mean peak HRM pressures when compared to presence or absence of vallecular stasis (1 ml saline: p = .1886; 10 ml saline: p = .7354). When categorized according to complete or incomplete tongue retraction, mean peak HRM pressures were significantly greater in the complete tongue retraction group as compared to incomplete tongue retraction (1 ml saline: p = .0223; 10 ml saline: p = .0100). Findings suggest there are multiple factors that lead to reduced vallecular clearance. In the absence of HRM measures, judging complete or incomplete tongue retraction on VFSS may be a more valid gauge of tongue base region pressures than vallecular clearance when planning dysphagia treatment.     

Power Spectra Analysis of Levator Veli Palatini Muscle Electromyogram During Velopharyngeal Closure for Swallowing,Speech, and Blowing

The velopharynx closes during swallowing and pneumatic activities. Pneumatic closure, which is acquired, prevents expiratory air from passing into the nasal cavity, whereas during swallowing, velopharyngeal closure is achieved innately, preventing regurgitation into the nasal cavity. These findings suggest that velopharyngeal closure during swallowing is a different mechanism from that during pneumatic activity. The purpose of this study was to clarify activity differences of the levator veli palatini muscle during swallowing, speech, and blowing using power spectra analysis. Five normal adults served as subjects. Each subject was instructed to speak, blow, and swallow. Electromyograms of the levator muscle were recorded and the spectrum analyzed for each task to calculate the mean power frequency (MPF) of EMG signals. There was no significant difference in MPF between speech and blowing for all subjects. MPF was significantly greater during swallowing than during pneumatic activities for all subjects. The MPF value can reflect the composition of active motor units during muscle contraction. It was therefore indicated that the motor units of the levator muscle participating in contraction were different during swallowing and respiratory activities.     

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 Chin-down Posture on Tongue Pressure during Dry Swallow and Bolus Swallows in Healthy Subjects

The purpose of this study was to investigate the influence of chin-down posture and bolus size on tongue pressure during swallowing. Eleven healthy volunteers (7 men, 4 women; age range = 26–59 years) participated in the experiments. Tongue pressure during dry and 5- and 15-ml water swallows in neutral and chin-down postures was measured using a sensor sheet system with five measuring points on the hard palate. Sequential order, maximal magnitude, duration, and integrated value of tongue pressure at each measuring point were compared between postures and bolus sizes. Onset of tongue pressure at posterior-circumferential parts occurred earlier in dry swallow than in 5- and 15-ml water swallows in each posture. Chin-down posture was most effective for increasing tongue pressure in the 5-ml water swallow compared with dry swallow and the 15-ml water swallow, but it had almost no influence on tongue pressure with the 15-ml water swallow. These results suggest that chin-down posture increases the tongue driving force for small boluses in healthy subjects, which can be interpreted to mean that oropharyngeal swallowing in a chin-down posture requires more effort.     

Using ultrasound to investigate intrapersonal variability in durational aspects of tongue movement during swallowing

The purpose of this study was to determine the extent of intrapersonal variability in durational aspects of tongue movement during swallowing. Using ultrasound, the entire duration of tongue movement and the duration of the oral transport stage during swallowing was measured in a group of patients with neurogenic swallowing disorder and a group of matched healthy control subjects. The results indicate considerable intrapersonal variability in both groups. The patient group performed significantly more variably in terms of the duration of the transport stage. However, when looking at individual results, this finding can not be generalized, in that some patients showed rather decreased variability. Other differences between patient the group and control subjects were not statistically significant. Ultrasound was found to be a highly suitable technique for the purpose of this study.     

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.     

Coordinative Organization of Lingual Propulsion during the Normal Adult Swallow

Lingual propulsion during swallowing is characterized by the sequential elevation of the anterior, middle, and dorsal regions of the tongue. Although lingual discoordination underlies many swallowing disorders, the coordinative organization of lingual propulsion during the typical and disordered swallow is poorly understood. The purpose of this investigation was to quantitatively describe the coordinative organization of lingual propulsion during the normal adult swallow. Tongue movement data were obtained from the X-Ray Microbeam Database at the University of Wisconsin. Movement of four pellets placed on specific tongue regions were tracked in 36 healthy adult participants while they swallowed 10 cc of water across five discrete trials. The propulsive action of the tongue during bolus transport was quantified using a cross-correlation analysis. Lingual transit time (LTT), which was defined as the interval (lag time) between the movements of the anterior- and posterior-most tongue regions, was determined to be approximately 168 ms. The average time interval (lag) between the movements of the posterior tongue regions was significantly shorter than the intervals between more anterior tongue regions. The results also suggest that during bolus transport movement patterns of the anterior tongue regions are distinct from those of the posterior tongue regions. Future work is needed to determine if the absence of the observed coordinative organization of lingual propulsion is indicative of oral stage dysphagia.     

Computer Measurement of Oral Movement in Swallowing

This article describes a computer program that automatically detects and tracks small metal markers affixed to a subject's tongue and teeth in fluoroscopic image sequences of swallowing. The program, written in Microsoft Visual C++ using Windows NT 4.0 and the SAVANT imaging toolkit, involves marker detection and marker tracking. Marker detection is done by template matching. A generic marker template was designed by extracting the grayvalues of pixels within an imaged marker. Template matching with a weighted center-of-mass calculation determined marker location with subpixel accuracy. Marker tracking employed a nearest-neighbor algorithm since (a) the movement of each marker was less than the distance between any two markers and (b) marker trajectories did not overlap. Effects of head motion were attenuated by computing tongue trajectories with respect to a constant frame of reference given by reference markers on the maxillary teeth. Motions were converted from pixels/frame to millimeters/second using a calibration ring secured to the subject's neck. Results for several image sequences showed that our program performs very well in terms of marker detection and trajectory determination. Comparison of automatic and manual tracking of the same image sequences indicated a high degree of correspondence. Automatic tracking of oral movement by computer is a useful tool in kinematic studies of swallowing.     

Eating and Breathing: Interactions Between Respiration and Feeding on Solid Food

Chewed solid food accumulates in the oropharynx prior to swallowing. The mechanism for preventing aspiration during this interval is unknown, but may be related to respiration. The purpose of this study was to determine how eating, especially bolus formation in the pharynx, affects respiration. We examined nasal air pressures, masseter electromyography (EMG), and videofluorography (VFG) of four normal young adults eating 8 g each of banana and cookie (two trials each food). Resting respiration was recorded for 30 s before eating. Respiratory cycles (RCs) were classified as prefeeding, feeding (excluding cycles with included swallows), and swallowing cycles. RC duration was greater for swallowing than for feeding and prefeeding RCs (P < 0.001). There were up to three swallows in a single RC, but the increase in swallowing RC duration was greater than swallow duration. Swallow apnea began before bolus transport through the hypopharynx and ended as the bolus tail entered the esophagus. There were semirhythmic perturbations in nasal air pressure associated with masseter activity during chewing, suggesting that there was oronasal airflow during jaw closing via the velopharyngeal isthmus. The most important finding was that bolus aggregation in the valleculae usually occurred during an extended plateau in nasal air pressure following active expiration. This suggests that aspiration during eating is prevented by inhibiting respiration during bolus formation in the oropharynx. Supported in part by award #R01-DC02123 from the National Institute on Deafness and other Communication Disorders of the National Institutes of Health.     

Esophageal motility disorders in terms of pressure topography: the Chicago Classification

Two recent advances have revolutionized the performance of clinical esophageal manometry; the introduction of practical high resolution manometry (HRM) systems and the development of sophisticated algorithms to display the expanded manometric dataset as pressure topography plots. We utilized a large clinical experience of 400 consecutive patients and 75 control subjects to develop a systematic approach to analyzing esophageal motility using HRM and pressure topography plots. The resultant classification scheme has been named as the Chicago Classification of esophageal motility. Two strengths of pressure topography plots compared with conventional manometric recordings were the ability to (1) delineate the spatial limits, vigor, and integrity of individual contractile segments along the esophagus and (2) to distinguish between loci of compartmentalized intraesophageal pressurization and rapidly propagated contractions. Making these distinctions objectified the identification of distal esophageal spasm, vigorous achalasia, functional obstruction, and nutcracker esophagus subtypes. Applying these distinctions made the diagnosis of spastic disorders quite rare: spasm in 1.5% of patients, vigorous achalasia in 1.5%, and a newly defined entity, spastic nutcracker, in 1.5%. Ultimately, further clinical experience will be the judge, but it is our expectation that pressure topography analysis of HRM data, along with its well-defined functional implications, will prove valuable in the clinical management of esophageal motility disorders.     

Dynamic aspects of lingual propulsive activity in swallowing

This investigation concerned the effect of different bolus volumes on the characteristics of lingual propulsive activity in swallowing. Young normal subjects were asked to perform dry swallows and swallows of 5, 10, and 15 ml of water. Tongue activity was recorded by tracking multiple gold pellets affixed to the tongue, utilizing the specialized research capabilities of the X-ray Microbeam facility at the University of Wisconsin. The major differences were between dry and liquid swallows, with dry swallows showing smaller range of movement, higher tongue position at the initiation of lingual propulsive activity, a slightly different direction of motion, a humped or flat rather than grooved cross-sectional contour of the tongue, lower peak velocity of motion, and slower progression of activity from tongue blade to dorsum. Within the 5–15 ml range of liquid bolus volumes, fewer consistent differences were found as a function of bolus size, and some marked individual differences in swallowing patterns were seen. Data are presented on normal within-subject variability in swallowing, with discussion of the possible contribution of sensory assessment of bolus size to the modification of oral and pharyngeal characteristics of swallowing.     

The Dynamics of Lingual-Mandibular Coordination During Liquid Swallowing

Previous literature on tongue-jaw relationships during swallowing has focused on behaviors observed with chewable solid foods. The present investigation was undertaken to evaluate both the nature and stability of coordinative relationships between the jaw and three points located along the midsagittal groove of the tongue—anterior (blade), middle (body), and posterior (dorsum)—during swallowing of thin and honey-thick liquids. A reiterative swallowing paradigm was used, with two task conditions (discrete and sequential), to explore the stability of tongue-jaw coordination across different frequencies of swallowing. Eight healthy participants in two age groups (young, older) performed sets of repeated swallows. Tongue and jaw movements were measured using electromagnetic midsagittal articulography. The data were analyzed in terms of variability in the spatiotemporal movement pattern for each fleshpoint of interest, and the temporal coupling (frequency entrainment) and relative phasing of movement for each tongue segment compared to the mandible. The results illustrate a stereotypical but not invariant sequence of movement phasing in the tongue-jaw complex during liquid swallowing and task-related reductions in variability at higher frequencies of swallowing in tongue dorsum movements. This evidence supports the idea that different segments of the tongue couple with the jaw as a synergy for swallowing, but can modify their coupling relationship to accommodate task demands.