Oropharyngeal Scintigraphy: A Reliable Technique for the Quantitative Evaluation of Oral–Pharyngeal Swallowing

A valid and reliable technique to quantify the efficiency of the oral–pharyngeal phase of swallowing is needed to measure objectively the severity of dysphagia and longitudinal changes in swallowing in response to intervention. The objective of this study was to develop and validate a scintigraphic technique to quantify the efficiency of bolus clearance during the oral–pharyngeal swallow and assess its diagnostic accuracy. To accomplish this, postswallow oral and pharyngeal counts of residual for technetium-labeled 5- and 10-ml water boluses and regional transit times were measured in 3 separate healthy control groups and in a group of patients with proven oral–pharyngeal dysphagia. Repeat measures were obtained in one group of aged (> 55yr) controls to establish test–retest reliability. Scintigraphic transit measures were validated by comparison with radiographic temporal measures. Scintigraphic measures in those with proven dysphagia were compared with radiographic classification of oral vs. pharyngeal dysfunction to establish their diagnostic accuracy. We found that oral (p = 0.04), but not pharyngeal, isotope clearance is swallowed bolus-dependently. Scintigraphic transit times do not differ from times derived radiographically. All scintigraphic measures have extremely good test–retest reliability. The mean difference between test and retest for oral residual was –1% (95% CI –3%–1%) and for pharyngeal residual it was –2% (95% CI –5%–1%). Scintigraphic transit times have very poor diagnostic accuracy for regional dysfunction. Abnormal oral and pharyngeal residuals have positive predictive values of 100% and 92%, respectively, for regional dysfunction. We conclude that oral–pharyngeal scintigraphic clearance is highly reliable, bolus volume-dependent, and has a high predictive value for regional dysfunction. It may prove useful in assessment of dysphagia severity and longitudinal change.     

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

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

Dynamics of Capsule Swallowing by Healthy Young Men and Capsule Transit Time from the Mouth to the Stomach

We examined the dynamics of capsule swallowing by healthy young men using the anterior-posterior view of videofluoroscopy as a first step in a study on capsule swallowing by dysphagic patients. The subjects were 14 healthy men who did not have any complaint of dysphagia. They were asked to swallow a #4 hard gelatin capsule filled with barium sulfate with 15 ml of water during the videofluoroscopic examination. This examination was repeated three times for each subject (total of 42 trials). In four of the 14 subjects, a swallowed capsule was retained at the upper esophageal sphincter, or the broncho-aortic constriction of the esophagus, or the lower esophageal sphincter. Except where retention occurred, the average capsule transit time from the mouth to the stomach was 6.0 ± 2.4 s. Three of the four subjects who had capsule retention did not realize that the swallowed capsule was retained en route to the stomach. By considering the dynamics of swallowing a capsule with 15 ml of water in healthy men, we should be able to reveal the dynamics of capsule swallowing in dysphagic patients, and the capsule transit time from the mouth to the stomach.     

``Wet Voice' as a Predictor of Penetration and Aspiration in Oropharyngeal Dysphagia

This article describes the results of a study that investigated how well wet phonation can predict penetration and/or aspiration of ingested material in dysphagic patients. Voice samples of 23 subjects with neurologic oropharyngeal dysphagia were collected immediately after each subject had swallowed nine different boluses on videofluoroscopy. The boluses were graded according to three different consistencies and three different sizes. The presence of wetness in the voice was analyzed in relation to any ingested material that remained in the larynx or trachea after each bolus was swallowed. Results showed that there was no association between the presence of a wet voice and penetration or aspiration of prandial material after a swallow. The importance of detecting wet phonation by itself was therefore not considered diagnostic in detecting prandial penetration/aspiration by the bedside, but a wet voice may still be useful in identifying those with dysphagia who may have laryngeal dysfunction and therefore may be at risk of penetrating/aspirating any type of material, not just prandial material.     

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.     

Assessment of esophageal motor function using combined multichannel intraluminal impedance and manometry in healthy volunteers: a single-center study in Taiwan

BACKGROUND: Combined multichannel intraluminal impedance and manometry (MII-EM) allow simultaneous measurement of both pressure and bolus transit. The aim of this study was to establish normative data in Chinese subjects for combined MII-EM and to correlate liquid and viscous bolus transit by impedance with esophageal contractions by manometry. METHODS: Eighteen normal volunteers (six women and 12 men; mean age 24 years, range 19-36 years) underwent combined MII-EM with a catheter containing four impedance-measuring segments and five solid-state pressure transducers. Each subject received 10 liquid and 10 viscous material swallows of 5 mL each. Tracings were analyzed for bolus presence time, total bolus transit time, contraction amplitude, duration, and onset velocity. RESULTS: A total of 180 liquid and viscous swallow responses were analyzed. In all, 98.4% percent of manometrically normal liquid and 97.7% of manometrically normal viscous swallows had complete bolus transit by impedance. More than half (56.3%) of manometrically ineffective liquid and 50% of ineffective viscous swallows had complete bolus transit. Nearly 90% of normal individuals had at least 70% complete liquid bolus transit while more than 90% of normal individuals had at least 70% complete viscous bolus transit. CONCLUSIONS: This study establishes normative data for combined MII-EM in a healthy Chinese population. These data will help provide impedance application in esophageal function testing with a reference range that could be utilized by future studies or clinical practices involving Chinese subjects.     

Scintigraphic measurement of oropharyngeal transit in man

Scintigraphic studies of the oropharyngeal transit of a liquid bolus were performed in 15 healthy controls, 12 patients with symptoms of oral-pharyngeal dysphagia, and 13 patients with neuromuscular disease, who did not have dysphagia. Gamma camera imaging of the head, neck, and upper thorax was undertaken, in the lateral projection, during the swallowing of the radiolabeled bolus of water. Inspection of summed images permitted the selection of regions of interest (ROI) to represent the mouth, pharynx, and upper esophagus. Transit times between each ROI were calculated and compared. Significant prolongation of bolus transit time between the mouth and esophagus was present in both patients with and without dysphagia (0.59 ± 0.38 sec and 0.33 ± 0.7 sec; mean ± SD, respectively) compared with controls (0.26 ± 0.04 sec P < 0.001, P < 0.01, respectively, Mann-Whitney U test). Repeat studies in 25 individuals indicated that the transit measurements were more reproducible between swallows in normal subjects than in patients with symptoms. Deglutitive scintigraphy provides a noninvasive technique for the quantitative study of swallowing and its disorders.     

Oral, pharyngeal, and esophageal transit of an acidic bolus in healthy subjects

Background

The swallowing function is influenced by chemical and sensory stimuli. The aim of this investigation was to evaluate the effect of an acidic sour bolus on its oral, pharyngeal, and esophageal transit in healthy volunteers.

Method

Scintigraphic evaluation of the transit was performed in 43 healthy subjects aged 23–71 years. Each subject swallowed, in a random sequence, 5 mL of two liquid boluses: acidic (50 mL of water with 3 g of concentrated lemon juice, pH 3.0) and neutral (water, pH 6.8), both labeled with 37 MBq of technetium-99m phytate. A series of images of each swallow were acquired at 20 frames/s for 20 s with the subjects sitting in front of the collimator of the gamma camera.

Results

There was no difference between neutral and acidic boluses in terms of their transit and clearance durations and in the amount of residues when passing through the mouth and pharynx. In the proximal esophagus, the transit and clearance were longer with the neutral bolus (clearance 1.40 ± 0.11 s) than with the acidic bolus (1.17 ± 0.07 s, p = 0.04). In the distal esophagus, the transit and clearance were longer with the acidic bolus (clearance 10.66 ± 0.87 s) than with the neutral bolus (6.60 ± 0.58 s, p = 0.01). The amount of residues in the middle and distal esophagus was greater with the acidic bolus. There was no correlation between distal esophageal clearance duration and the amount of residues with the neutral bolus, but there was a positive correlation with the acidic bolus.

Conclusion

An acidic bolus causes slower bolus transit in the distal esophageal body as compared to a neutral bolus.     

Quantitative assessment of swallowing in healthy adults

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

Oral and Pharyngeal Transit of a Paste Bolus in Chagas’ Disease

We measured the oral and pharyngeal transit of a paste bolus in 20 patients with Chagas' disease and 21 controls. Each subject swallowed of a 10-ml paste bolus prepared with 50 ml of water and 4.5 g of instant food thickener labeled with 55.5 MBq of 99m technetium phytate. After the scintigraphic recording of the transit, we delineated regions of interest (ROI) corresponding to mouth, pharynx, and proximal esophagus. Time-activity curves were generated for each ROI. There was no difference between patients with Chagas' disease and controls with respect to the duration of oral and pharyngeal transit, amount of pharyngeal residue, or flux of bolus entry into the proximal esophagus. The amount of oral residue was higher in patients with Chagas' disease (median = 0.71 ml) than in controls (median = 0.45 ml). The pharyngeal clearance duration was longer in patients with Chagas' disease (median = 0.85 s) than in controls (median = 0.60 s). The oral transit duration of the patients with Chagas' disease and dysphagia (median = 0.55 s, n = 14) was shorter than the oral transit duration of chagasic patients without dysphagia (median = 0.80 s, n = 6). We conclude that when swallowing a paste bolus, patients with Chagas' disease may have an increased amount of oral residue and a longer pharyngeal clearance duration than asymptomatic volunteers.     

Scintigraphic quantification of pharyngeal retention following deglutition

A procedure is described for quantifying the amount of bolus material retained in the pharynx after completion of a swallow, using radionuclide swallow techniques. Data are derived from scintigraphic time-activity curves. The procedure takes into consideration the differential attenuation of radioactivity through various regions in the body, and expresses the result as a percentage of the total radioactivity in the ingested bolus. Illustrative examples are provided for swallows by normal individuals and patients with head and neck cancer.     

Detection of esophageal motor disorders by radionuclide transit studies

Radionuclide measurement of esophageal transit has been proposed as a screening test for esophageal motor dysfunction. In this study we evaluated the radionuclide esophageal transit test in 49 consecutive patients undergoing esophageal manometry for esophageal motor disorders. Esophageal transit was assessed using a 10-ml water bolus labeled with 250 Ci technetium-99m sulfur colloid. In preliminary studies in 14 healthy controls, mean transit time was 9.6±2.1 (SD) sec. Prolonged transit (>15 sec) was observed in two of 28 swallow sequences in the control subjects. Transit times were prolonged in all patients with achalasia or diffuse esophageal spasm, and in five of seven patients with nonspecific abnormalities of peristaltic progression. The test was abnormal in only three of seven patients with high-amplitude peristalsis (nutcracker esophagus) and in none of three patients with hypertensive lower esophageal sphincter. Additionally, prolonged transit was seen in two of 18 patients with normal manometry. We conclude that the radionuclide transit test using a liquid bolus successfully identifies motor disorders characterized by defective peristaltic progression but not disorders in which peristalsis is intact. A major limiting factor appears to be the small number of swallow sequences tested. The test may not, therefore, be accurate enough to consider adopting as a sensitive and noninvasive screening test in the evaluation of patients with suspected esophageal motor disorders.     

The Coordination of Breathing and Swallowing in Parkinson’s Disease

Multiple investigations have determined that healthy adults swallow most often during exhalation and that exhalation regularly follows the swallow, even when a swallow occurs during inhalation. We hypothesized that persons with idiopathic Parkinson's disease would demonstrate impaired breathing and swallowing coordination during spontaneous eating. Twenty-five healthy volunteers and 25 Parkinson's disease patients spontaneously swallowed calibrated pudding and cookie portions while simultaneous nasal airflow and respiratory inductance plethysmography were used to track spontaneous breathing. Surface EMG was used to record the timing of each swallow within the respiratory cycle. When compared to the healthy control group, those with Parkinson's disease swallowed significantly more often during inhalation and at low tidal volumes. The Parkinson's participants also exhibited significantly more postswallow inhalation for both consistencies. Only the healthy subjects exhibited significantly longer deglutitive apnea when swallows that occurred during inhalation were compared with those that occurred during exhalation. The high incidence of oropharyngeal dysphagia and risk of aspiration pneumonia found in Parkinson's disease patients may be partially attributable to impaired coordination of breathing and swallowing.     

Viscosity effects on EMG activity in normal swallow

This study investigated the effects of six consistencies on measures of swallow duration, muscle activity, and sound. Electromyographic (EMG) recordings of the submental and infrahyoid muscle complexes, and audio recordings of neck sounds were made while 5 normal subjects swallowed two foods in each of three consistency categories: liquid, thin paste, and thick paste. Total swallow duration, measured from EMG, increased significantly across consistency categories from liquids to thin pastes to thick pastes. Liquids and thin pastes were significantly different from thick pastes on all but one EMG measure. However, liquids and thin pastes failed to reach significance on any of the EMG measures. EMG activity in the submental muscles most often initiated the swallow whereas the infrahyoid muscle activity most frequently terminated the swallow. A sound spike occurred at relatively the same time in each swallow. Results are discussed in terms of systematic modulations of muscle activity during swallow.     

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.     

Hyoid-Bolus Transit Latencies in Normal Swallow

Pharyngeal swallow delay is frequently found in dysphagic patients and is thought to be a factor in a range of swallowing problems, including aspiration. Implicit in notions of swallow “delay” is a temporal interval between two events that is longer than normal. However, there appears to be little agreement about which referent events should be considered in determining delay. A number of pharyngeal bolus transit points and various pharyngeal gestures have been used in delays determined from fluoroscopic evidence, and other referents have been used in electromyographic and manometric studies of swallow. In this study latencies between the first movement of the hyoid and several pharyngeal bolus transit points were calculated from fluoroscopic swallow studies in normal nondysphagic adults. Means and standard deviations of these latencies are provided for a 3-cc and a 20-cc bolus and for both nonelderly and elderly adults. The data may be a useful resource for relating the specific latencies investigated to concepts of pharyngeal swallow delay, in particular, when assessing videofluoroscopic studies using a similar protocol.     

Esophageal function testing with combined multichannel intraluminal impedance and manometry: multicenter study in healthy volunteers.

BACKGROUND & AIMS: Combined multichannel intraluminal impedance and manometry (MII-EM) assesses esophageal function by simultaneous measurement of both pressure and bolus transit. Normative data for this method have not been published. The aim of this study was to establish normative data for combined MII-EM and to correlate liquid and viscous bolus transit by impedance with esophageal contractions by manometry. METHODS: Forty-three normal volunteers recruited from 4 centers (15 women, 28 men; age range, 21-72 years) underwent combined MII-EM with a catheter containing 4 impedance-measuring segments and 4 solid-state pressure transducers. Each center recruited and analyzed subjects independently, according to pre-established criteria. Each subject received 20 x 5 mL swallows, 10 liquid and 10 viscous material. Tracings were analyzed manually for bolus presence time, bolus head advance time, segmental transit times, total bolus transit time, contraction amplitude, duration, and onset velocity. RESULTS: Ninety-seven and four-tenths percent of manometrically normal liquid and 96.1% of manometrically normal viscous swallows had complete bolus transit by impedance. Almost half (47.2%) of manometrically ineffective liquid and 34.7% of ineffective viscous swallows had complete bolus transit, whereas 91.7% of manometric simultaneous liquid swallows and 54.5% of simultaneous viscous swallows had complete bolus transit. More than 93% of normal individuals had at least 80% complete liquid or at least 70% complete viscous bolus transit. CONCLUSIONS: This study establishes normative data for combined MII-EM. Combined MII-EM may be a more sensitive tool in assessing esophageal function compared to standard manometry because impedance can distinguish different bolus transit patterns. Studies in patients with manometrically defined esophageal motility abnormalities should help clarify the functional importance of manometric ineffective and simultaneous swallows.     

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

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

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.     

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.