Age-Related Differences in Pressures Generated During Isometric Presses and Swallows by Healthy Adults

The aim of this prospective observational study was to determine the associations among age, maximum lingual isometric pressures, and maximum swallow pressures in specific regions of the tongue. Individuals 21 years and older who reported normal swallowing were enrolled. Seventy-one healthy adults were stratified by age into young (21–40 years), middle (41–60), and old (61–82) groups. Maximum pressures were measured for each individual during isometric tongue press tasks as well as saliva, 5, and 10 mL thin liquid bolus swallows at 5 sensors located on the hard palate: front, middle, left, right, and back. Lower maximum lingual pressures for all tasks were associated with increased age (p < 0.04). Saliva pressures exhibited a different pressure pattern than bolus swallows with pressures higher than bolus swallows on middle (p < 0.03) and back (p < 0.05) tongue sensors but not in the front. Diminished swallow pressure reserve (maximum isometric pressure–maximum swallow pressure) also was found with increased age (p < 0.03). Isometric pressures were greater than swallow pressures in young and middle age groups at both the front (p < 0.04) and back (p < 0.03) sensors, but only significantly greater at the front sensor for the oldest group (p < 0.04). Older healthy adults have lower lingual isometric pressures and lower swallow pressures than younger healthy adults. Elders have a decreased swallow pressure reserve to draw upon during occasions of physiological stress. While the exact mechanisms for age-related decline in lingual pressures remain unclear, they are likely due, at least in part, to sarcopenia. Saliva, 5, and 10 mL thin boluses also exhibit different age-related declines in pressure at specific sensors, indicating they may elicit different muscle activation patterns.     

Pressure-flow dynamics of the oral phase of swallowing

In 5 healthy volunteers, we studied the pressure-flow kinetics of the oral phase of swallowing. The regional profile within the oral cavity during swallowing was recorded, at the tongue tip (T₁), dorsum of the tongue (T₂), 3 cm from the tongue tip, oral floor, buccal cavity, and between the lips during swallows of water (0–20 ml) and 5 ml of mashed potato. Two strain gauge (SG) probes, each with two transducer recording sites 3 cm apart, were used for recording pressure. Supralingual and sublingual pressure were recorded concurrently. The relationship between transit of a barium bolus and deglutitive oral pressure phenomena was determined by concurrent videoradiography and manometry. Lingual pressure with the SG facing the tongue showed the most consistent recording and highest pressure: 193±16 (SE) mmHg at T₁ and 214±18 mmHg at T₂ for dry swallows. Pressures were similar for water swallows. However, mashed potato swallows produced a pressure of 383±30 mmHg at T₁ and 485±52 mmHg at T₂ that were greater than for water swallows (p<0.01). Pressure recorded with the transducers facing the hard palate and, to a lesser extent, laterally, was low and inconsistent. Oral-floor pressure was greatest with the transducers oriented upwards and averaged 64±2.9 mmHg proximally and 173±36 mmHg distally. At all sites the pressure waves propagated sequentially, toward the pharynx. Minimal pressure increases occurred in the buccal cavity. Lip squeeze varied from 0 to 90 mmHg. We can draw the following conclusions. The oral phase of swallowing includes contraction of the oral floor, which provides a platform for tongue movement. Oral pressure waves propagate toward the pharynx so that a swallowed bolus is propelled ahead of the point of lingual-palatal closure. Lingual peristalsis exhibits a wide range of pressures, with lower pressure for dry and liquid boluses than for a semisolid bolus. Buccal and lip contractions act as stabilizing forces, but do not contribute to bolus propulsion. Significant differences exist in the radial pressure profile of lingual peristalsis, with maximal pressure oriented toward the tongue.     

A Study of Interrater Reliability when Using Videofluoroscopy as an Assessment of Swallowing

Videofluoroscopic assessment of swallowing is widely used in clinical settings. The interpretation of such assessments depends on subjective visual judgments but the reliability of these judgments has been poorly researched. This study measured interrater reliability of judgments, made by speech pathologists, of videofluoroscopic images of subjects swallowing liquid and semisolid boluses. A 5-point rating scale was used in three conditions: individually after careful reading; together with other speech pathologists in group discussion; and individually after the group discussion. Analysis of the ratings for the three conditions revealed that the level of agreement among raters was generally higher for semisolid swallows than for liquid swallows. The highest levels of agreement occurred for ratings made after group discussions. The levels of agreement were lowest when raters worked alone, relying only on reading the scale. Individual rating after group discussion resulted in higher levels of agreement than sole reliance on reading the scale. Factors influencing the levels of interrater agreement, including the timing of observations, bolus consistency, the quality of the image, and the complexity of the task, are discussed.     

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.     

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.     

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.     

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.     

The Effects of Intraoral Pressure Sensors on Normal Young and Old Swallowing Patterns

Lingual pressure generation plays a crucial role in oropharyngeal swallowing. To more discretely study the dynamic oropharyngeal system, a 3-bulb array of pressure sensors was designed with the Kay Elemetrics Corporation (Lincoln Park, NJ). The influence of the device upon normal swallowing mechanics and boluses representative of flow relative to age and bolus condition was the focus of this study. Twelve healthy adults in two age groups (31 ± 5 years, 2 males and 4 females, and 78 ± 7 years, 2 males and 4 females) participated. Each subject was instructed to swallow four boluses representative of conditions with and without three pressure sensors affixed to the hard palate. Postswallow residue at four locations, Penetration/Aspiration Scale scores, and three bolus flow timing measures were assessed videofluoroscopically with respect to age and bolus condition. The only statistically significant influences attributable to the presence of the pressure sensors were slight increases in residue in the oral cavity and upper esophageal sphincter with some bolus consistencies, 8% more frequent trace penetration of the laryngeal vestibule predominantly with effortful swallowing, and variances in oral clearance duration. We conclude that the presence of the pressure sensors does not significantly alter normal swallowing patterns of healthy individuals. This article is GRECC No. 03-01. This work was supported by NIH Grant NS24427 and VA Grant E727-2RA.     

健康老年妇女吞咽功能的研究

目的　通过电视X线透视吞咽功能的研究 ,评价健康老年妇女液体吞咽运动 ,并对液体吞咽运动的影响因素进行分析。　方法　 4 0例健康老年妇女 ,老年前期组 (5 0～ 5 9岁 ) 2 0例 ;老年组 2 0例 ,年龄 6 0～ 79岁。进行电视X线透视液体吞咽功能检查 ,分别对口咽部相关结构进行运动学分析 ,比较不同液体食团体及年龄对健康老年妇女吞咽的影响。　结果　 (1 )老年组较老年前期组渗透、口咽部滞留发生率增高 ,两组渗透发生率分别为 :7 5 %、3 8% ;口腔滞留发生率分别为 :1 2 5 %、6 3% ;咽腔滞留发生率分别为 :2 6 5 %、1 7 5 % ;口咽传递时间、腭咽部关闭时间及环咽部开放时间延长 (均为P <0 0 5 ) ;喉、舌骨向上运动距离增大 (P <0 0 5 )。 (2 ) 1 0ml食团较 1ml渗透、口咽部滞留发生率增高 ,两组渗透发生率分别为 :8 8%、2 5 % ;口腔滞留发生率分别为 :1 3 8%、5 0 % ;咽腔滞留发生率分别为 :31 3%、1 3 8% ;口传递时间缩短而环咽部开放时间延长 (均为P <0 0 5 ) ;喉向上、前运动 ,舌骨向前、向上运动的距离增大 (P <0 0 5 )。　结论　临床应用电视X线透视吞咽功能检查并对口咽期吞咽功能进行运动学分析是可行的 ;年龄及食团体积均影响健康老年妇女的液体吞咽功能     

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.     

Swallow respiratory patterns and aging: presbyphagia or dysphagia?

BACKGROUND: Assessment referrals are increasing for unexpected dysphagia, particularly for older people. It is unclear if this is due to more impaired swallows or healthy age-related changes. Swallow respiration coordination prevents aspiration, and may deteriorate with age. Nonpathological features of the swallow in healthy aging and the factors that influence an individual's ability to eat and drink safely need greater understanding. Some changes might predispose an older person to dysphagic complications in the event of an insult such as a stroke. We investigated the effects of healthy aging on resting and swallow respiratory patterns. METHODS: Fifty healthy volunteers (aged 20-78 years) were recruited to have swallow respiration patterns recorded on a computer. Bolus volume and consistency variations were studied: 5 and 20 ml of water and 5 ml of yogurt. RESULTS: Measurable swallows significantly decreased with age for water boluses. Swallow apnea increased with age (5 ml of water r = 0.433, p = .002; 5 ml of yogurt r = 0.367, p = .023). Independent of age were: breathing out (occurred after 98% of boluses); multiple swallowing (occurred with all bolus types); post-swallow respiration reset pattern (more irregular after yogurt, Wilcoxon signed rank Z = -2.236, p = .025); and resting respiration. CONCLUSIONS: Subtle changes occur in swallow respiration coordination with age. These changes may be compensatory protective mechanisms rather than the result of decreased muscle mobility or reaction times, and not indicative of impairment. Misattributing healthy age-related changes to impairment affects patient care and the use of healthcare resources.     

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 swallowing reflex by lung volume changes

We investigated the effects of changes in lung volume on coordination of respiration and swallowing in 11 healthy subjects. Swallowing reflexes were elicited by bolus injections of a small amount of distilled water (1 ml) and by continuous infusion of distilled water (3 ml/min) into the pharynx at three different levels of lung volume. The lung volume was changed by application of negative extrathoracic pressure (0, -20, and -40 cm H(2)O). We found that increases in lung volume prolonged the latency of swallows elicited by bolus injection of water and decreased the number of swallows during continuous infusion of water. In addition, the preponderant coupling of swallows with the expiratory phase observed before application of negative extrathoracic pressure was lost during application of negative extrathoracic pressure. These results may indicate that lung inflation has an inhibitory influence on the swallowing reflex, and modulates the timing of swallowing in reference to the respiratory cycle.     

Influence of Bolus Consistency on Lingual Behaviors in Sequential Swallowing

Thickened liquids are a commonly recommended intervention for dysphagia. Previous research has documented differences in temporal aspects of bolus transit for paste versus liquid consistencies; however, the influence of liquid viscosity on tongue movements during swallowing remains unstudied. We report an analysis of the influence of bolus consistency on lingual kinematics during swallowing. Electromagnetic midsagittal articulography was used to trace tongue body and dorsum movement during sequential swallows of three bolus consistencies: thin, nectar-thick, and honey-thick liquids. Rheological profiling was conducted to characterize viscosity and density differences among six liquids (two of each consistency). Eight healthy volunteers participated; four were in a younger age cohort (under age 30) and four were over the age of 50. The primary difference observed across the liquids of interest was a previously unreported phenomenon of sip-mass modulation; both flavor and density appeared to influence sip-sizing behaviors. Additionally, significantly greater variability in lingual movement patterns was observed in the older subject group. Systematic variations in lingual kinematics related to bolus consistency were restricted to the variability of downward tongue dorsum movement. Otherwise, the present analysis failed to find empirical evidence of significant modulations in tongue behaviors across the thin to honey-thick consistency range.     

Evaluation of Swallowing in Children with Vomiting After Feeding

Vomiting after feeding is a symptom of gastroesophageal reflux (GER) and of eosinophilic esophagitis (EE), which are considered to be a cause of infant feeding disorder. The objective of the present study was to evaluate swallowing in children with feeding disorder manifested by vomiting after feeding. Using clinical and videofluoroscopic methods we studied the swallowing of 37 children with vomiting after feeding (mean age=15.4 months), and of 15 healthy children (mean age=20.5 months). In the videofluoroscopic examination the children swallowed a free volume of milk and 5 ml of mashed banana, both mixed with barium sulfate. We evaluated five swallows of liquid and five swallows of paste. The videofluoroscopic examination was recorded at 60 frames/s. Patients had difficulty during feeding, pneumonia, respiratory distress, otitis, and irritability more frequently than controls. During feeding, children with vomiting, choke were irritable, and refused food more frequently than controls, and during the videofluoroscopic examination the patients had more backward movement of the head than controls for both the liquid and paste boluses. There was no difference in the timing of oral swallowing transit, pharyngeal swallowing transit, or pharyngeal clearance between patients and controls. We conclude that children with vomiting after feeding may have difficulties in accepting feeding, although they have no alteration of oral and pharyngeal phases of swallowing.     

Esophageal solid bolus transit: studies using combined multichannel intraluminal impedance and manometry in healthy volunteers

The purpose of this study is to apply combined multichannel intraluminal impedance and esophageal manometry (MII‐EM) to test esophageal function during solid swallowing in a normal healthy population. We determined whether combined MII‐EM with solid bolus is more sensitive than that with viscous bolus in the detection of motility abnormality. Eighteen healthy volunteers (11 men and 7 women; mean age 22 years, range 20–26 years) underwent combined MII‐EM with a catheter containing four impedance‐measuring segments and five solid‐state pressure transducers. Each subject received 10 viscous and 10 solid materials. Tracings were analyzed manually for bolus presence time, total bolus transit time, contraction amplitude, duration, and onset velocity. Three hundred and sixty swallows including viscous and solid materials were analyzed. Contraction amplitude for the viscous swallows was higher at 20 cm above the lower esophageal sphincter (LES) (P= 0.049) but lower at 15 cm above the LES (P < 0.001). Duration of contractions for the solid swallows was longer at 15 cm (P= 0.002) and 10 cm above the LES (P= 0.011) compared with viscous swallows. The total bolus transit time for solid was significantly shorter than that for viscous boluses (6.8 vs. 7.7 seconds, P < 0.001). Bolus presence time appeared to be similar between viscous and solid boluses (except in the proximal esophagus). The percentage of swallows with ineffective peristalsis by manometry, as well as those with incomplete bolus transit by impedance, did not differ between viscous and solid swallows. The proportion of manometrically ineffective solid swallows with incomplete bolus transit was greater than that of viscous swallows (62.1% vs. 34.8%, P= 0.05). Application of solid boluses may potentially enhance diagnostic capability of esophageal function testing. Solid boluses can be regarded as a valuable complement to viscous boluses in the detection of esophageal motility abnormalities when applied with combined MII‐EM.     

Determining normal bolus size for thin liquids

In order to define a suitable volume of barium to be delivered to patients during the radiographic evaluation of pharyngoesophageal function during swallowing, three different age groups of nondysphagic volunteers were studied. Subjects randomly swallowed boluses of water, barium, and Coca-Cola. The size of a normal thin liquid bolus was 21 ml (SD±5 ml). We intend to include this information to compare different bolus sizes in cineradiographic examination of patients with swallowing complaints.     

Durational aspects of oral swallow in neurologically normal children and children with cerebral palsy: An ultrasound investigation

Little data exist on the oral management of food boluses in neurologically normal children or children with cerebral palsy (CP). Twenty children with spastic CP and 20 neurologically normal children (age range: 6.2–12.9 years) were monitored with ultrasound imaging of the oral cavity during liquid and solid bolus tasks. A lip-cup contact detector synchronized to ultrasound image output was used during liquid tasks. Data collected from recorded ultrasound images were used to assess durational aspects of the oral phase of swallowing in neurologically normal children and children with CP. Coordinated analysis of ultrasound images with lip-cup contact data allowed timing of intervals in the pre-oral and oral phases of swallowing during liquid feeding tasks. Children with CP required more time than neurologically normal children for collection, preparation, oral transit, and total oral swallow time for 5-ml liquid boluses. Total oral swallow time was longer for solid bolus tasks in children with CP. Oral transit time for solid boluses was significantly longer than for liquid boluses in neurologically normal children and children with CP.     

Esophageal solid bolus transit: studies using concurrent videofluoroscopy and manometry

OBJECTIVE: Our aim was to assess the efficacy and mechanism of solid bolus transit through the esophagus. METHODS: Eight healthy volunteers were studied with concurrent manometry and videofluoroscopy while swallowing 5 ml liquid barium, a 5-6 mm diameter bread ball, and 4 g chewed bread in both a supine and upright posture. As many as four successive swallows were performed until clearance was achieved. RESULTS: The esophageal clearance of liquid barium was 100% with the first swallow. Clearance of the unchewed bread ball occurred with the first swallow in only 6.7% of trials in the upright posture and 5.9% in the supine posture. After four swallows, clearance was 100% and 52.9% in the upright and supine postures, respectively. Chewed bread was more readily cleared than unchewed bread, with 100% clearance after two swallows in the upright posture and 91% clearance after four swallows in the supine posture. The most common locus of bread stasis was at the aortic arch and carina. The bread boluses were noted to move more effectively when localized in the head as opposed to the tail of the bolus composite. Nonocclusive contractions often occurred at the bolus tail despite the increased peristaltic amplitude seen with the chewed bread. Failed peristalsis, a frequent cause for solid clearance failure, was observed during 30% of all bread swallows. This usually occurred distal to the stopping point of the bolus, suggesting it to be the result rather than the cause of impaired transit. CONCLUSIONS: Although infrequently perceived by these normal subjects and in contradistinction to liquid clearance, bread is rarely cleared from the esophagus with a single swallow. Mastication and an upright posture facilitate the esophageal transport of solids. Bolus composition and impaired bolus transit alter the amplitude and conductance of peristalsis. Manometric data pertaining to liquid clearance through the esophagus do not readily apply to bread.     

Breathing-swallowing interaction in neuromuscular patients: a physiological evaluation

RATIONALE: Malnutrition and aspiration are major problems in patients with neuromuscular disease. Because impaired swallowing contributes to malnutrition, means of improving swallowing are needed. OBJECTIVES: To investigate interactions between breathing and swallowing in neuromuscular disorders and to evaluate the impact of mechanical ventilation (MV) on swallowing in tracheostomized patients. METHODS: We studied 10 healthy individuals and 29 patients with neuromuscular disease and chronic respiratory failure (including 19 with tracheostomy). The tracheostomized patients who could breathe spontaneously were recorded during spontaneous breathing (SB) and with MV, in random order. MEASUREMENTS AND MAIN RESULTS: Breathing-swallowing interactions were investigated by chin electromyography and inductive respiratory plethysmography, using three water-bolus sizes (5, 10, and 15 ml) in random order. In contrast to healthy individuals, neuromuscular patients showed piecemeal deglutition with several swallows over several breathing cycles for each bolus. The percentage of swallows followed by expiration was about 50% in the patients compared with nearly 100% in the control subjects. The number of swallows and total swallowing time per bolus correlated significantly to maximal inspiratory pressure. In the 10 tracheostomized patients who were recorded both in SB and MV, the number of swallows and total swallowing time per bolus were significantly reduced during MV compared with SB. CONCLUSION: Neuromuscular patients showed abnormal breathing-swallowing interactions, which correlated to maximal inspiratory pressure. Moreover, MV improved the swallowing parameters in tracheostomized patients who were able to breathe spontaneously.