Preliminary Investigation of Swallowing Apnea Duration and Swallow/Respiratory Phase Relationships in Individuals with Cerebral Vascular Accident

Swallowing apnea duration (SAD) and swallow-respiratory phase relationships were examined in individuals with cerebral vascular accident (CVA) and dysphagia who aspirated (n = 11) and did not aspirate (n = 15). Simultaneous videofluoroscopic and respiratory measures were recorded across 5-, 10-, 15-, and 20-ml thin and thick liquid bolus trials. These data were also compared with that previously acquired with healthy older adults (n = 20). A moderate amount of systematic missing data was evidenced in the individuals who were dysphagic and especially those who aspirated subsequently limiting inferential analyses. Only 1 of the 11 participants who aspirated and 7 of the 15 who did not aspirate completed all 16 conditions. Six of the remaining ten who aspirated had missing data subsequent to termination of trials due to aspiration risk. The remaining four and seven of the eight who did not aspirate had missing data due to poor respiratory waveforms. From the remaining data, it was found that SAD and respiratory phase relationships differed among individuals with dysphagia and CVA (i.e., those who aspirate vs. those who do not aspirate) and healthy older adults. SAD was found to be longer for those who aspirated versus those who did not for all bolus viscosities and volumes with the exception of thick-liquid 10-ml boluses. In addition, SAD from those that aspirated was twice as long as that found in healthy older adults for all conditions. Regarding respiratory phase relationships, there was a difference between the proportions of respiratory patterns in those who aspirated versus those who did not. Those who aspirated demonstrated a markedly greater percentage of swallows that interrupted inhalation. In addition, the inhale-swallow-inhale pattern occurred with a greater frequency as swallowing severity increased. Healthy older adults, those who did not aspirate, and those who aspirated used the inhale-swallow-inhale pattern 0.1%, 3.0%, and 9.0%, respectively.     

Effects of Age, Gender, Bolus Volume, and Trial on Swallowing Apnea Duration and Swallow/Respiratory Phase Relationships of Normal Adults

The effects of age, gender, bolus volume, and trial on swallowing apnea duration (SAD) and swallow/respiratory phase relationships were examined. Sixty adults, composed of ten males and ten females in each of three age groups (i.e., 20–39, 40–59, and 60–83 years), participated. SAD was assessed via nasal airflow during saliva swallows and 10-, 15-, 20-, 25-mL bolus volumes across three trials. Results revealed SAD is consistent across trial (p>0.05). Significant main effects of age, gender, and bolus volume were found (p<0.05), i.e., elderly adults had longer SAD than young and middle-aged adults; women had longer SAD than men; and SAD increased as bolus volume increased. With respect to saliva swallows, a significant interaction of age by gender was found (p<0.05), i.e., males exhibited a decrease in SAD with increasing age while females exhibited an increase in SAD with increasing age. Concerning swallow/respiratory phase relationships, the pattern of exhale–swallow–exhale was evident during 62% of participants' swallows. Furthermore, age, gender, or bolus volume did not predict the pattern of exhale–swallow–exhale (p>0.05). Submitted February 23, 2000; accepted October 2, 2000     

Volume accommodation during swallowing

Bolus volume is an important modifier of the biomechanical events of the oropharyngeal swallow. The biomechanical events comprising a swallow can be divided into events associated with the reconfiguration of the pharynx into a swallow pathway and events associated with bolus transport from the oropharynx into the esophagus. Volume modification is achieved differently for the events of reconfiguration and propulsion. In the case of reconfiguration, a longer time is allocated to the process, as exemplified by sustained laryngeal elevation and hyoid excursion during larger volume swallows. On the other hand, in the case of bolus expulsion, volume accommodation is accomplished within the same period of time by utilizing increased vigor of expulsion. The result of deglutitive volume accommodation is a remarkably different fluoroscopic appearance of a small vs. a large volume swallow. The larger volume swallow seemingly takes longer and results in much more vigorous bolus expulsion than a small volume. However, this is more related to the bolus than the swallow.     

Common Medical Conditions in the Elderly:Impact on Pharyngeal Bolus Transit

Deglutition in the elderly may be impacted by the sequelae of medical diseases. It is unknown if the long-term presence of common medical diseases, such as arthritis and hypertension, leads to changes in neurologic and muscular function and thus swallowing ability. The aim of this project was to determine if the duration of bolus pharyngeal transit in nondysphagic elderly individuals with chronic medical problems is longer than that measured in nondysphagic elderly individuals without medical problems. Videofluoroscopic swallowing studies were performed on 63 elderly subjects with a variety of well-controlled medical problems and on 23 elderly subjects with no medical problems. The mean timing of pharyngeal bolus transit was compared between the two groups. The relationship between the presence of medical problems and the likelihood of transit times prolonged beyond two standard deviations of the mean transit time found in 60 younger normal controls was also analyzed. Findings included significantly prolonged pharyngeal transit time in the group of subjects with medical problems compared with those subjects without medical problems for a small bolus size. Those individuals with hypertension demonstrated the most significant delays in bolus transit. The presence of medical problems did correlate with an increased likelihood of prolonged transit times. This preliminary study indicates that medical problems common in elderly populations are associated with a deterioration of swallowing function and that changes identified in elderly individuals may not be due to aging alone.     

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.     

Evaluation of a Solid Bolus Suitable for Esophageal Scintigraphy

This study was designed to select a suitable solid bolus for esophageal scintigraphy. Optimally, a bolus should leave minimal residual buccal and pharyngeal activity after being swallowed. We compared the oropharyngeal behavior of three boluses, i.e., omelette, egg white, and paté of 1- and 3-ml volume. Thirty patients without dysfunction of the upper esophageal sphincter were recruited for the study. Scintigraphy interpretation was based on the results of condensed images and time activity curves. A total of 108 oropharyngeal transits were analyzed. First we determined the most appropriate volume (1 or 3 ml) of paté, omelette, and egg white (i.e., the volume with the least residual oropharyngeal activity). Buccal or pharyngeal bolus retention occurred significantly less frequently with 1 ml paté than 3 ml (p = 0.03) and also less frequently with 3 ml egg white than with 1 ml egg white (p = 0.03), and the mean buccal bolus retention index was lower using 3 ml omelette than 1 ml omelette (p = 0.03). Then we identified the most suitable of the three selected boluses. Both oral and pharyngeal residues were higher for paté (1 ml) than for omelette (p = 0.02 and 0.05), and pharyngeal residue was significantly lower for omelette (3 ml) than for egg white (3 ml) (p = 0.02). In conclusion, a 3-ml bolus of radiolabeled omelette seems to be the most suitable bolus for exploration of esophageal transit, and its use could enhance the potential of scintigraphy in the assessment of esophageal disorders.     

Activities of the Muscles Involved in Swallowing in Patients with Cleft Lip and Palate

This study was designed to examine the nature of the activity of swallowing muscles in patients with cleft lip and palate (CLP). The electromyographic activity of the thyrohyoid muscle (TH), the geniohyoid muscle (GH), and the myohyoid muscle (MH) of patients with CLP (CLP group) was analyzed and compared with noncleft subjects (control group) during swallowing and drinking water with and without artificial nasal obstruction. In the normal situation without nasal obstruction, a significant (p < 0.01) difference in muscle activity between the two groups was found only for TH. In the control group, the duration and magnitude of muscle activity were significantly (p < 0.01) larger in all the muscles when a nasal obstruction was applied. Meanwhile, in the CLP group these values exhibited a significant (p < 0.05) increase in GH and MH only. With nasal obstruction, the burst durations of GH and MH became significantly (p < 0.01) longer in the control group than in the CLP group. The amplitude of GH activity during swallowing was significantly (p < 0.05) larger in the control group than in the CLP group. These results suggest that in CLP patients during swallowing, TH working from the pharyngeal stage compensates for the weakness of GH and MH working in the oral phase. This may cause a premature transfer of the bolus to the pharynx before making it properly into the oral cavity.     

Airway Protection: Evaluation with Videofluoroscopy

During videofluoroscopic swallowing studies performed in the lateral view, the arytenoid cartilages are seen to elevate and approximate the down-folding epiglottis, effectively closing the supraglottic larynx and protecting the airway. This mechanism may be incomplete or delayed in patients complaining of dysphagia and may lead to penetration of bolus material into the airway. This study evaluates the timing of supraglottic closure relative to the arrival of the bolus at the upper esophageal sphincter in 60 young control subjects and in 63 elderly control subjects without dysphagia. Event timing was measured in 0.01-s intervals from videofluoroscopic studies for two liquid bolus size categories. Results of the analysis revealed that, in most individuals, the arytenoid cartilages approximate the epiglottis prior to the arrival of the bolus at the upper esophageal sphincter. However, in both bolus size categories, there were individuals who achieved complete supraglottic closure after the bolus had arrived at the sphincter, but never greater than 0.1 s later. No delay in the timing of supraglottic closure relative to bolus arrival at the sphincter was found in the elderly subject group compared with the young subject group. The information from this study has allowed us to objectively determine if supraglottic closure timing is delayed in patients with dysphagia and to address any delay with strategies and exercises designed specifically to correct the delay. A case study is presented to illustrate the clinical significance of this study.     

Effects of systematic bolus viscosity and volume changes on hyoid movement kinematics

Using ultrasonography with head and transducer stabilization, this study examined the effects of maximally controlled, systematic changes in bolus viscosity (thin juice-like, 7 cP; nectar-like, 243–260 cP; honey-like, 724–759 cP; spoon-thick, 2760–2819 cP) and volume (5, 10, 20, 30 cc) on hyoid kinematics in 31 healthy subjects (16 male, 15 female) in three age groups (20–39, 40–59, 60–79 years). Frame-by-frame hyoid displacements were tracked from digitized images of 612 swallows. Measures of movement durations, maximal amplitudes, total distances, and peak velocities were subjected to repeated measures multivariate analyses of variance with viscosity, volume, age, and gender as factors. Results showed that (1) spoon-thick swallows had the greatest preswallow gesture and total movement durations; (2) larger-volume swallows had significantly greater maximal amplitudes, forward peak velocity, and total vertical distance; (3) older subjects had longer start-to-max duration (though shorter preswallow gesture and total movement durations), greater maximal vertical amplitude, longer total vertical distance, and greater backward peak velocity than younger subjects; (4) males had greater values for all kinematic parameters except preswallow gesture, hyoid-at-max, and max-to-end durations. The results illustrate the importance of examining the interrelations among kinematic variables to better understand task accommodation and motor control strategies. The evidence also supports the concept of suprahyoid–infrahyoid functional adaptation and compensation in the healthy elderly.     

Effect of Gender on Swallow Event Duration Assessed by Videofluoroscopy

There are data suggesting that women swallow liquids at a lower flow rate and ingest smaller volumes in each swallow than men. Our objective in this work was to compare swallowing in asymptomatic men and women by videofluoroscopy. We studied 18 men [age = 33–77 years, mean = 61 (10) years] and 12 women [age = 29–72 years, mean = 53 (15) years] who swallowed in duplicate 5 and 10 ml of liquid and paste barium boluses. None of the volunteers had dysphagia, neurologic diseases, or oral, pharyngeal, or esophageal diseases. The videofluoroscopic examination showed that for the 5-ml bolus, women had a longer oropharyngeal transit [liquid: men, 0.63 (0.21) s, women, 0.88 (0.39) s; paste: men, 0.64 (0.35) s, women, 0.94 (0.58) s], longer oral transit [liquid: men, 0.41 (0.21) s, women, 0.59 (0.35) s; paste: men, 0.39 (0.28) s, women, 0.59 (0.42) s], and longer pharyngeal clearance [liquid: men, 0.36 (0.11) s, women, 0.45 (0.16) s; paste: men, 0.42 (0.25) s, women, 0.56 (0.27) s] compared with men (p < 0.05). We conclude that there are differences in swallowing between men and women, with women having a longer oropharyngeal transit than men for a 5-ml bolus.

Laryngeal Penetration During Deglutition in Normal Subjects of Various Ages

This study examined the frequency of penetration of liquid, paste, and masticated materials into the airway during videofluoroscopic studies of normal swallow in 98 normal subjects who were from 20 to 94 years of age. The purposes of the study were to define frequency and level of penetration using the penetration-aspiration scale as a result of age, bolus volume, viscosity, and gender, and to describe the body's sensorimotor response to the penetration based on audible coughs or throat clearing on the audio channel of each videotaped fluoroscopic study. Frequencies of penetration were defined in relation to bolus volume, age, gender, and bolus viscosity from swallows of 1, 3, 5, and 10 ml and cup-drinking of thin liquids; 3 ml of pudding; (1/4) of a Lorna Doone cookie; and a bite of an apple. Results showed that penetrations were significantly more frequent after age 50 and thick viscosities penetrated only in subjects age 50 and over. For persons under 50, 7.4% of swallows exhibited penetration, while for people age 50 and over, 16.8% of swallows showed penetration. Significantly more penetration occurred on larger liquid boluses. There was no relationship between gender and frequency of penetration. None of the subjects that penetrated showed a sensorimotor response to the penetration, which may relate to the relatively shallow depth of the penetration.     

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.     

Oropharyngeal swallowing after stroke in the left basal ganglion/internal capsule

One of the foci of Martin Donner's work was the neural control of swallowing. This present investigation continues that work by examining oropharyngeal swallowing in 8 patients identified with a single, small, left-basal ganglion/internal capsule infarction and 8 age-matched normal subjects. Stroke patients were assessed with a bedside clinical and radiographic swallowing assessment, and normal subjects received only the radiographic study. Results revealed disagreement between the bedside and radiographic assessments in one of the 8 stroke patients. Stroke and normal subjects differed significantly on some swallow measures on various bolus viscosities, but behaved the same as normal subjects on a number of measures. Differences in swallowing in the stroke subjects were not enough to prevent them from eating orally. The significant differences seen in the basal ganglia/intemal capsule stroke subjects may result from damage to the sensorimotor pathways between the cortex and brainstem. These differences emphasize the importance of cortical input to the brainstem swallowing center in maintaining the systematic modulations characteristic of normal swallowing physiology.     

Post-Laryngectomy: It’s Hard to Swallow An Australian Study of Prevalence and Self-reports of Swallowing Function After a Total Laryngectomy

The prevalence of swallowing disorders (dysphagia) following a total laryngectomy remains unknown, with estimates varying from 17 to 70%. The primary aim of this study was to investigate the prevalence and nature of self-reported dysphagia following a total laryngectomy across New South Wales (NSW), Australia. A secondary aim was to document the effect of dysphagia on the respondents’ social activities and participation. A questionnaire battery, with a prepaid envelope for return, was sent to all laryngectomy members (n = 197) of the Laryngectomee Association of NSW. One hundred twenty questionnaires (61%) were completed and returned. Dysphagia was self-reported by 71.8% of the cohort. In this cohort with dysphagia, the most commonly reported features included an increased time required to swallow, a need for fluids to wash down a bolus, and avoidance of certain food consistencies. Severe distress was reportedly associated with dysphagia for 39.7% of these respondents and prevented 57% of them from participating in social activities, such as eating at friends’ houses and/or at restaurants. The prevalence of self-reported dysphagia following total laryngectomy in this Australian study was 72%. Dysphagia can result in laryngectomees making significant changes to their diets and it has a marked impact on their activities and social participation.

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.     

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.     

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.     

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.     

Systemic Autoimmune Diseases in Patients Hospitalized with COVID-19 in Spain: A Nation-Wide Registry Study

We aimed to evaluate the clinical outcome of Systemic Autoimmune Diseases (SADs) patients hospitalized with COVID-19 in Spain, before the introduction of SARS-CoV-2 vaccines. A nationwide, retrospective and observational analysis of the patients admitted during 2020, based on the ICD10 codes in the National Registry of Hospital Discharges, was performed. Among 117,694 patients, only 892 (0.8%) presented any type of SAD before COVID-19-related admission: Sjogren’s Syndrome constituted 25%, Systemic Vasculitides 21%, Systemic Lupus Erythematosus 19%, Sarcoidosis 17%, Systemic Sclerosis 11%, Mixed and Undifferentiated Connective Tissue Disease 4%, Behçet’s Disease 4% and Inflammatory Myopathies 2%. The in-hospital mortality rate was higher in SAD individuals (20% vs. 16%, p < 0.001). After adjustment by baseline conditions, SADs were not associated with a higher mortality risk (OR = 0.93, 95% CI 0.78–1.11). Mortality in the SADs patients was determined by age (OR = 1.05, 95% CI 1.04–1.07), heart failure (OR = 1.67, 95% CI 1.10–2.49), chronic kidney disease (OR = 1.29, 95% CI 1.05–1.59) and liver disease (OR = 1.97, 95% CI 1.13–3.44). In conclusion, the higher COVID-19 mortality rate seen in SADs patients hospitalized in Spain in 2020 was related to the higher burden of comorbidities, secondary to direct organ damage and sequelae of their condition. Whilst further studies should evaluate the impact of baseline immunosuppression on COVID-19 outcomes in this population, efforts should be focused on the optimal management of SAD to minimize the impact of the organ damage that has been shown to determine COVID-19 prognosis.