Coordination of breathing and swallowing: effects of bolus consistency and presentation in normal adults

Timing of True Vocal Cords Closure for Safe Swallowing: A Review of 5 Studies Using 3D Analysis Using Computerized Tomography (CT)

Timely and complete laryngeal closure is critical for a successful swallow. Researchers have studied laryngeal closure, including true vocal cords (TVC) closure, closure of the arytenoids to the epiglottis base (laryngeal vestibule closure), and epiglottic inversion, but the most commonly available imaging tools have limitations that do not allow the study of these components individually. Swallowing computerized tomography (CT) has enabled three-dimensional dynamic visualization and quantitative evaluation of swallowing events providing a unique view of swallowing-related structures and their motion. Using CT, TVC closure can be visualized and evaluated on any plane or cross-section without being obscured by of laryngeal vestibule closure or epiglottis inversion. The current review summarizes the results of five papers evaluating the effects of bolus consistency and volume, posture, and age on TVC closure. The combined results of these studies suggest that TVC closure is responsive to oral sensory input based on bolus consistency and size and can be modulated in response to conditions perceived to increase the risk of airway invasion. These results are meaningful for dysphagia rehabilitation as it suggests that interventions to improve TVC closure are likely to enhance airway protection.

Respiratory-Swallow Coordination in Individuals with Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Swallowing impairment, including altered physiology and aspiration, occur across the progression of Parkinson's disease (PD). The phase of respiration during which a swallow is initiated has been linked to swallowing impairment and aspiration in cohorts with dysphagia following stroke and head and neck cancer treatment, but has been understudied in PD. If similar findings are shown in individuals with PD, the implications for swallowing assessment and treatment are significant.

OBJECTIVE

The aim of this systematic review and meta-analysis of literature was to examine respiratory-swallow coordination measures and potential implications on swallowing physiology in individuals with PD.

METHODS

An extensive search of 7 databases (PubMed, EMBASE, Central, Web of Science, ProQuest Dissertations & Theses, Scopus, and CINAHL) with predetermined search terms was conducted. Inclusion criteria were individuals with PD and the use of objective evaluations of respiratory-swallow coordination.

RESULTS

Of the 13,760 articles identified, 11 met the inclusion criteria. This review supports the presence of atypical respiratory swallow patterning, respiratory pause duration and lung volume at swallow initiation in individuals with PD. The meta-analysis estimated an occurrence of 60% of non-expiration-expiration and 40% of expiration-expiration respiratory phase patterns surrounding swallowing.

CONCLUSION

Although this systematic review supports the occurrence of atypical respiratory-swallow coordination in individuals with PD, the evidence is limited by the variability in the methods of data acquisition, analysis, and reporting. Future research examining the impact of respiratory swallow coordination on swallowing impairment and airway protection using consistent, comparable, and reproducible methods and metrics in individuals with PD is warranted.

Effects of Bolus Holding on Respiratory-Swallow Coordination in Parkinson's Disease

PURPOSE

The aim of this study was to examine the effects of bolus holding on respiratory-swallow coordination (RSC) in people with Parkinson's disease (PD).

METHOD

People with PD were prospectively recruited to undergo RSC assessment using simultaneous respiratory inductive plethysmography and flexible laryngoscopy. During RSC assessment, participants swallowed 5-ml thin liquid boluses during held and nonheld swallowing tasks. Measures of RSC were analyzed for each swallow, which included respiratory pause duration, lung volume at swallow initiation, respiratory phase patterning, and the presence of paradoxical respiratory movements. Multilevel statistical modeling was used to determine if differences in RSC were present between the held and nonheld tasks.

RESULTS

Thirty-three participants were enrolled. When compared to the nonheld swallows, the held swallows exhibited shorter respiratory pauses (p = .001, R ² = .019), lower lung volumes at swallow initiation (p < .001, R ² = .116), more frequent exhale-swallow-exhale patterns (p < .001, OR = 4.30), and less frequent paradoxical respiratory movements (p = .001, OR = 0.43).

CONCLUSIONS

Findings from this study revealed that bolus holding significantly influences RSC in people with PD. This demonstrates that bolus holding may be an efficacious strategy to immediately improve RSC in PD. However, clinicians and researchers should consider avoiding bolus holding during swallowing evaluations if attempting to assess RSC behaviors that are most typical for the examinee.

Clinical Practice Patterns of Speech-Language Pathologists Delivering Dysphagia Services to Persons with COPD: Analysis of Survey Outcomes

Swallowing impairments co-occur with chronic obstructive pulmonary disease (COPD) leading to aspiration, disease exacerbations, and malnutrition. This pilot survey study aimed to identify current clinical practice patterns for swallowing evaluation and treatment in persons with COPD. A 35-question Qualtrics survey was deployed to medical speech-language pathology (SLP) social media sites and professional boards; flyers were distributed at a professional conference. Forty-eight SLPs completed the study. SLPs routinely include a clinical swallow examination (96%), videofluoroscopic swallowing study (79%), adjunctive respiratory measures (respiratory rate [83%], and pulse oximetry [67%], respiratory-swallow pattern [77%]) but less frequently include fiberoptic endoscopic evaluation of swallowing (23%). Self-reported advanced clinical experience and expert respiratory analysis skills were associated with adjunctive respiratory measure (respiratory rate, pulse oximetry) inclusion during assessment. Compensatory strategy training (77%) is a preferred treatment for dysphagia in COPD; however, respiratory-swallow pattern training and expiratory muscle strength training are increasing in use. SLPs self-report a comprehensive, individualized patient-centered care approach with inclusion of adjunctive respiratory-focused methods in dysphagia evaluation and treatment practice in persons with COPD. Advances in the identification of the integral role of respiratory function in swallowing integrity may be translating to clinical practice methods for dysphagia management in persons with COPD.

An Exploration of Lung Volume Effects on Swallowing in Chronic Obstructive Pulmonary Disease

Purpose Chronic obstructive pulmonary disease (COPD) limits respiration, which may negatively impact airway safety during swallowing. It is unknown how differences in lung volume in COPD may alter swallowing physiology. This exploratory study aimed to determine how changes in lung volume impact swallow duration and coordination in persons with stable state COPD compared with older healthy volunteers (OHVs). Method Volunteers ≥ 45 years with COPD (VwCOPDs; n = 9) and OHVs (n = 10) were prospectively recruited. Group and within-participant differences were examined when swallowing at different respiratory volumes: resting expiratory level (REL), tidal volume (TV), and total lung capacity (TLC). Participants swallowed self-administered 20-ml water boluses by medicine cup. Noncued (NC) water swallows were followed by randomly ordered block swallowing trials at three lung volumes. Estimated lung volume (ELV) and respiratory-swallow patterning were quantified using spirometry and respiratory inductive plethysmography. Manometry measured pharyngeal swallow duration from onset of base of tongue pressure increase to offset of negative pressure in the pharyngoesophageal segment. Results During NC swallows, the VwCOPDs swallowed at lower lung volumes than OHVs (p = .011) and VwCOPDs tended to inspire after swallows more often than OHVs. Pharyngeal swallow duration did not differ between groups; however, swallow duration significantly decreased as the ELV increased in VwCOPDs (p = .003). During ELV manipulation, the COPD group inspired after swallowing more frequently at REL than at TLC (p = .001) and at TV (p = .002). In conclusion, increasing respiratory lung volume in COPD should improve safety by reducing the frequency of inspiration after a swallow.

Respiratory-swallow coordination and swallowing impairment in head and neck cancer

BACKGROUND

The aim of the study was to determine the link between frequency of optimal respiratory-swallow coordination, swallowing impairment, and airway invasion in head and neck cancer (HNC) patients.

METHOD

A cross-sectional study of a heterogeneous group of HNC patients (49), precancer (N = 30) or postcancer treatment (N = 29), participated in a single Modified Barium Swallow Study (MBSS) with synchronized respiratory data.

RESULTS

Spearman correlation coefficients revealed significant negative correlations between optimal respiratory-swallow phase pattern and objective measures of swallowing impairment: penetration-aspiration scale max, pharyngeal total, and oral total scores with Spearman correlation coefficients of -0.53 (z .001), -0.50 (P < .001), and -0.43 (P = .002), respectively. Optimal respiratory-swallow pattern was significantly decreased (P = .03) in patients after cancer treatment compared with another patient group before cancer treatment.

CONCLUSION

These findings indicate that as the percentage of optimal respiratory-swallow phase patterns increase, swallowing impairment decreases in the HNC patient population.

The Risk of Penetration-Aspiration Related to Residue in the Pharynx

Purpose Reference data from healthy adults under the age of 60 years suggest that the 75th and 95th percentiles for pharyngeal residue on swallows of thin liquids are 1% and 3%(C2-4)2, respectively. We explored how pharyngeal residue below versus above these values prior to a swallow predicts penetration-aspiration. Method The study involved retrospective analysis of a previous research data set from 305 adults at risk for dysphagia. Participants swallowed six thin boluses and three each of mildly, moderately, and extremely thick barium in videofluoroscopy. Raters measured preswallow residue in %(C2-4)2 units and Penetration-Aspiration Scale (PAS) scores for each swallow. Swallows were classified as (a) "clean baseline" (with no preswallow residue), (b) "clearing" swallows of residue with no new material added, or (c) swallows of "additional material" plus preswallow residue. Frequencies of PAS scores of ≥ 3 were compared across swallow type by consistency according to residue severity (i.e., ≤ vs. > 1%(C2-4)2 and ≤ vs. > 3%(C2-4)2. Results The data set comprised 2,541 clean baseline, 209 clearing, and 1,722 swallows of additional material. On clean baseline swallows, frequencies of PAS scores of ≥ 3 were 5% for thin and mildly thick liquids and 1% for moderately/extremely thick liquids. Compared to clean baseline swallows, the odds of penetration-aspiration on thin liquids increased 4.60-fold above the 1% threshold and 4.20-fold above the 3% threshold (mildly thick: 2.11-fold > 1%(C2-4)2, 2.26-fold > 3%(C2-4)2). PAS scores of ≥ 3 did not occur with clearing swallows of moderately/extremely thick liquids. Lower frequencies of above-threshold preswallow residue were seen for swallows of additional material than for clearing swallows. Compared to clean baseline swallows, the odds of PAS scores of ≥ 3 on swallows of additional material increased ≥ 1.86-fold above the 1% threshold and ≥ 2.15-fold above the 3% threshold, depending on consistency. Conclusion The data suggest that a pharyngeal residue threshold of 1%(C2-4)2 is a meaningful cut-point for delineating increased risk of penetration-aspiration on a subsequent swallow.

Respiratory-Swallow Training Methods: Accuracy of Automated Detection of Swallow Onset, Respiratory Phase, Lung Volume at Swallow Onset, and Real-Time Performance Feedback Tested in Healthy Adults

Background Preliminary studies have shown that respiratory-swallow training (RST) is a successful treatment for oropharyngeal head and neck cancer patients with refractory dysphagia. Refining the RST protocol with automated analysis software to provide real-time performance feedback has the potential to improve accessibility, reproducibility, and translation to diverse clinical settings. Method An automated software program for data acquisition and analysis developed to detect swallows, determine respiratory phase, calculate lung volume at the onset of the swallow, and provide real-time performance feedback was tested for feasibility in a small cohort of healthy adults. Outcome Measures Percent difference in swallow detection and accuracy of real-time performance feedback of respiratory phase and lung volume at swallowing onset between the automated software and the manual gold standard method were determined. Results The automated software program accurately detected the onset of the swallow on 91% of the swallows completed during the training trials. Feedback of respiratory phase and lung volume was accurate on 94% of the trials in which the swallow was accurately detected. Conclusions This novel, automated, and real-time RST software successfully detected the onset of the swallow, respiratory phase, and lung volume at swallow onset and provided appropriate real-time performance feedback with a high degree of accuracy in healthy adults. The software has the potential to improve the accessibility, efficiency, and translation of RST to diverse patient populations.

Respiratory Inductance Plethysmography for Automated Swallowing Detection

In the context of remote medical monitoring of swallowing, the authors investigate the potential of non-invasive respiratory inductance plethysmography (RIP) technique to automatically detect swallow events in a wide context of respiration and phonation. Signal acquisitions were carried out on 5 healthy volunteers equipped with RIP and electroglottograph as swallowing reference. They were asked for spontaneous breathing, speaking and diverse bolus ingesting. The RIP signal was then segmented into cycles, each cycle being annotated according to one of the three class of interest, respectively ventilation i.e. spontaneous breathing (1257 cycles), swallowing (221) and phonation (216). Automated classification was performed using quadratic discriminant analysis. Focusing on swallowing class, the authors achieve an accuracy of 79% from the full wide protocol. It increases up to 86% with prior removal of vocalizations. These preliminary results in healthy subjects make RIP a promising candidate as a non-invasive and convenient technology for medical follow-up of swallowing.

Respiratory-Swallow Coordination in Healthy Adults During Drinking of Thin to Extremely Thick Liquids: A Research Note

Purpose Respiratory-swallow coordination is vital for airway protection, preventing aspiration, or penetration of foreign material into the airway. With the implementation of the International Dysphagia Diet Standardization Initiative definitions for different liquid consistencies used in dysphagia management, it is important to establish whether respiratory-swallow coordination patterns differ across these consistencies. This study aimed to evaluate respiratory behaviors during swallowing across the spectrum from thin to extremely thick liquids in healthy adults less than 60 years of age. Method Thirty healthy adults, aged 21-55 years, each consumed 54 naturally sized cup sips or spoonfuls of liquid stimuli prepared in thin, slightly thick, mildly thick, moderately thick, and extremely thick consistencies. Half of the stimuli were prepared using barium and half with a lemon-flavored water. Concurrent respiratory and swallowing pressure signals were collected to evaluate the respiratory phase pattern and pause duration associated with the swallow. Results An expiration-swallow-expiration pattern was the dominant respiratory phase pattern, observed in 92.7% of the trials, with no significant effect of consistency. Respiratory pause duration was found to be significantly shorter with barium stimuli (0.73 s) compared to nonbarium stimuli (0.78 s) (p < .001, Cohen's d = .2), with no notable effects based on the factors of sex or liquid consistency. Conclusions In a convenience sample of healthy adults under the age of 60 years, consistent respiratory-swallow phasing and stable timing across the spectrum from thin to extremely thick liquids was observed. The data from this study can serve as preliminary reference data to which assessment information for individuals with dysphagia or respiratory challenges can be compared.

A Systematic Review of the Influence of Bolus Characteristics on Respiratory Measures in Healthy Swallowing

There have been a number of studies on the effect of bolus volume, consistency, texture, temperature and taste on the oropharyngeal swallowing physiology. However, its influence on the respiratory function associated with swallow is not well understood. This study aimed at systematically analysing and documenting the prevailing research literature on respiratory functions before, during, and after healthy swallows of boluses with varied characteristics. The PRISMA guidelines were followed for retrieval of relevant research. From among the 48,329 reports screened for inclusion criteria, 25 articles were included for data extraction. Each of these reports was evaluated for its design, methodology and reporting quality and also the level of evidence provided by them. The results revealed that the scientific evidence in this regard was restricted to level II. Majority of the studies included considered bolus volume as the variable than bolus consistency, taste or temperature. Expiratory phase was preferred surrounding the apnea irrespective of volume, consistency or taste but changed with temperature variations across age groups. The reports are equivocal on the duration of respiratory apnea, and length of respiratory cycles before and after the apnea. The temporal coordination of pharyngeal swallow events was found to be independent of bolus volume. This review concluded that bolus characteristics have differential effects on the respiratory functions during swallow beyond a 'central sensory threshold' level. Objective standardization of bolus characteristics may be the immediate requirement for generalization of future research findings in this direction.

Respiratory-Swallow Coordination Training and Voluntary Cough Skill Training: A Single-Subject Treatment Study in a Person With Parkinson's Disease

Purpose Airway protective disorders are common in Parkinson's disease (PD), yet effective methods to rehabilitate these life-threatening impairments are limited. This study examined the effects of two skill-based treatments aimed at improving swallowing and cough in a severely dysphagic person with PD: respiratory-swallow coordination training (RSCT) and voluntary cough skill training (VCST). It was hypothesized that (a) RSCT would improve respiratory-swallow coordination and swallowing safety and efficiency and (b) VCST would improve reflex and voluntary cough effectiveness. Method An 81-year-old man with midstage PD and severe dysphagia was recruited for study participation. The study utilized a multiple-baseline ABACA experimental design with a 2-month delayed retention assessment. Measures of respiratory-swallow coordination, swallowing safety and efficiency, and cough effectiveness were collected at each assessment using respiratory inductive plethysmography, flexible endoscopic evaluations of swallowing, and spirometry. Data were analyzed descriptively using baseline corrected tau and standard mean difference effect sizes (d). Results Large effect sizes were observed immediately following RSCT for respiratory-swallow coordination (d = 9.17), penetration-aspiration (d = 12.88), vallecular residue (d = 1.75), piriform residue (d = 4.15), and overall dysphagia severity (d = 1.83). Large effect sizes were also observed immediately following VCST for single voluntary cough (d = 4.30), sequential voluntary cough (d = 3.28), and reflex cough (d = 5.58). Improvements were maintained 2 months later for all outcome measures except single voluntary cough. Discussion This is the first study to examine the effects of RSCT and VCST in a person with PD. Robust improvements in respiratory-swallow coordination and swallowing safety and efficiency were achieved following four sessions of RSCT, and significant improvements in reflex and voluntary cough strength were seen following four sessions of VCST. Future work is needed to study these treatments in larger cohorts of people with PD.

The pilot study examining the effects of swallowing position on lung volume fraction and the coordination between respiration and non-nutritive swallowing reflex

Background

Body position might affect the coordination between respiration and swallowing. This study was carried out to test the hypothesis that during swallowing, coordinated movements of muscle groups such as the diaphragm and rectus abdominis muscles are important to control normal swallowing apnea.

Objective

To investigate this hypothesis, respiratory parameters, swallowing apnea and muscle activity were measured in each of four body positions: sitting position with feet on the floor, 30° reclining position, lateral position, and standing position.

Methods

All measurements were performed in nine healthy subjects. Nasal airflow was measured using a pneumotachometer and muscle activity was measured using an electromyograph. All lung volume fraction parameters were measured using spirometer and swallowing apnea time was calculated.

Results

The maximum inspiratory volume was 2.76 ± 0.83 L in the 30° reclining position, which was significantly larger than that in the other positions (p = .0001). The preliminary expiratory volume was 1.05 ± 0.42 L in the 30° reclining position, which was significantly smaller than that in the other positions (p < .0001). The swallowing apnea time during water swallowing was 1.17 ± 0.35 sec in the lateral position and 0.87 ± 0.28 sec in the 30° reclining position, which tended to be longer than the 0.78 sec in the sitting position.

Conclusion

We conclude that both lateral and reclining positions require a longer period of swallowing apnea compared to the sitting and standing positions. Differences in body position may significantly influence the coordination between respiration and swallowing.

Respiratory Phase and Lung Volume Patterns During Swallowing in Healthy Adults: A Systematic Review and Meta-Analysis

Purpose The coordination of respiration with swallowing is critical for facilitation of airway protection and the efficiency of movements that propel ingested material through the upper aerodigestive tract. Confirmation of a predominant pattern in healthy adults provides a platform for comparison to aberrant patterns observed in the population with swallowing impairment (dysphagia). Method A comprehensive search of published research in MEDLINE via PubMed 1946-2018, Embase 1947-2018, and Proquest Dissertations & Theses Global 1861-2018 was completed. Results Thirty-seven articles meeting inclusion criteria were selected for data extraction, and the findings were reviewed. In addition, a meta-analysis of the data was completed. A significantly higher occurrence ( p < .001) of expiration prior to and following the swallow was found when compared to 3 other patterns. The predominance of the pattern was influenced by increases in bolus volume when controlling for participant sample size. Conclusion Determination of this predominant pattern provides a normative framework for evaluating respiratory-swallow coordination in adults across the age span and highlights the relevance for assessing and incorporating respiratory swallowing coordination during assessment and interventions.

Evaluation of normal swallowing functions by using dynamic high-density surface electromyography maps

BACKGROUND

Swallowing is a continuous process with substantive interdependencies among different muscles, and it plays a significant role in our daily life. The aim of this study was to propose a novel technique based on high-density surface electromyography (HD sEMG) for the evaluation of normal swallowing functions.

METHODS

A total of 96 electrodes were placed on the front neck to acquire myoelectric signals from 12 healthy subjects while they were performing different swallowing tasks. HD sEMG energy maps were constructed based on the root mean square values to visualize muscular activities during swallowing. The effects of different volumes, viscosities, and head postures on the normal swallowing process were systemically investigated by using the energy maps.

RESULTS

The results showed that the HD sEMG energy maps could provide detailed spatial and temporal properties of the muscle electrical activity, and visualize the muscle contractions that closely related to the swallowing function. The energy maps also showed that the swallowing time and effort was also explicitly affected by the volume and viscosity of the bolus. The concentration of the muscular activities shifted to the opposite side when the subjects turned their head to either side.

CONCLUSIONS

The proposed method could provide an alternative method to physiologically evaluate the dynamic characteristics of normal swallowing and had the advantage of providing a full picture of how different muscle activities cooperate in time and location. The findings from this study suggested that the HD sEMG technique might be a useful tool for fast screening and objective assessment of swallowing disorders or dysphagia.

Assessment of impaired coordination between respiration and deglutition in children and young adults with ataxia telangiectasia

AIM

This cross-sectional investigation aimed to assess the value of non-invasive measures of temporal respiratory-swallow coupling in individuals with ataxic swallowing.

METHOD

Twenty participants (11 males, 9 females; range 9-21y) with ataxia telangiectasia were presented with water and pudding boluses. Their 193 swallows were compared with 2200 swallows from 82 age-matched healthy controls. The two components of airway protection during swallowing that were analyzed were: direction of peri-deglutitive airflow and duration of deglutitive inhibition of respiratory airflow (DIORA).

RESULTS

Safe expiratory patterns of peri-deglutitive airflow occurred significantly less often in participants with ataxia telangiectasia than in age-matched control participants (younger p<0.015 and older p<0.001). The frequency of an expiratory pattern of peri-deglutitive airflow increased with age in participants in the comparison group (p=0.006), but not in those with ataxia telangiectasia (p=0.234). With age, mean duration of DIORA decreased in controls (p<0.001) but was unchanged in participants with ataxia telangiectasia (p=0.164).

INTERPRETATION

Non-invasive quantitative measures of respiratory-swallow coupling capture temporal relationships that plausibly contribute to airway compromise from dysphagia. Changes in respiratory-swallow coupling observed with advancing age in control participants were not seen in participants with ataxia telangiectasia. Measures of perturbations may herald swallowing problems prior to development of pulmonary and nutritional sequelae.

Respiratory-swallowing coordination in normal subjects: Lung volume at swallowing initiation

This study was designed to investigate the significance of bolus types and volumes, delivery methods and swallowing instructions on lung volume at swallowing initiation in normal subjects in a single experiment using a multifactorial approach. Our broad range goal was to determine optimal lung volume range associated with swallowing initiation to provide training targets for dysphagic patients with disordered respiratory-swallow coordination. Our hypothesis was that swallows would be initiated within a limited range of quiet breathing lung volumes regardless of bolus volume, consistency or task. Results confirmed this hypothesis and revealed that swallows were initiated at mean lung volume=244ml. Cued swallows were initiated at lower quiet breathing volumes than un-cued swallows (cued=201ml; un-cued=367ml). Water boluses were initiated at slightly higher quiet breathing volumes than solids. Data suggest that swallows occur within a restricted range of lung volumes with variation due to instructions, bolus type and other experimental variables.

Dysphagia Screening: Contributions of Cervical Auscultation Signals and Modern Signal-Processing Techniques

Cervical auscultation is the recording of sounds and vibrations caused by the human body from the throat during swallowing. While traditionally done by a trained clinician with a stethoscope, much work has been put towards developing more sensitive and clinically useful methods to characterize the data obtained with this technique. The eventual goal of the field is to improve the effectiveness of screening algorithms designed to predict the risk that swallowing disorders pose to individual patients' health and safety. This paper provides an overview of these signal processing techniques and summarizes recent advances made with digital transducers in hopes of organizing the highly varied research on cervical auscultation. It investigates where on the body these transducers are placed in order to record a signal as well as the collection of analog and digital filtering techniques used to further improve the signal quality. It also presents the wide array of methods and features used to characterize these signals, ranging from simply counting the number of swallows that occur over a period of time to calculating various descriptive features in the time, frequency, and phase space domains. Finally, this paper presents the algorithms that have been used to classify this data into 'normal' and 'abnormal' categories. Both linear as well as non-linear techniques are presented in this regard.

[Effect of body position on coordination of breathing and swallowing]

BACKGROUND

To allow passage of food, the swallowing process closes off the larynx and interrupts respiratory flow. Both the timing of the interruption of respiratory flow and the body position can affect the results of the swallowing process.

OBJECTIVE

The effect of body position on the swallowing process and the coordination of breathing and swallowing is investigated.

MATERIALS AND METHOD

A combined EMG/bioimpedance measurement system and a piezoelectric sensor were used to investigate coordination of breathing and swallowing of a range of food consistencies in three different body positions (90°, 45° and 0°) in healthy subjects.

RESULTS

Investigations were carried out on 21 healthy subjects (12 ♂, 9 ♀). 762 swallows were recorded. Changing body position was found to have a statistically significant effect on swallow-related parameters (maximum laryngeal elevation and speed of laryngeal elevation) and breathing pattern (pre- and post-swallow breathing phases). The laryngeal elevation as well as the speed of the laryngeal elevation is influenced significantly by the consistency to be swallowed. The breathing pattern changes from saliva to solid food of inspiration/swallow/inspiration to expiration/swallow/expiration. A change of body position influences the parameters specific for swallowing and the breathing patterns significantly.

CONCLUSIONS

This study demonstrates that body position affects coordination of breathing and swallowing and swallow-related parameters in healthy subjects. Our results indicate that patients should be enabled to adopt a position in which they are sitting at an angle of at least 45°.

Respiratory-swallow training in patients with head and neck cancer

OBJECTIVE

To test a novel intervention to train swallowing to occur in the midexpiratory to low expiratory phase of quiet breathing to improve swallowing safety and efficiency.

DESIGN

Safety and efficacy nonrandomized controlled trial with 1-month follow-up.

SETTING

Ambulatory clinics.

PARTICIPANTS

Patients (N=30) with head and neck cancer (HNC) and chronic dysphagia completed the intervention. Fifteen of these patients participated in a 1-month follow-up visit.

INTERVENTIONS

Training protocol based on hierarchy of motor skill acquisition to encourage autonomous and optimal respiratory-swallowing coordination. Visual feedback of respiratory phase and volume for swallowing initiation was provided by nasal airflow and rib cage/abdomen signals.

MAIN OUTCOME MEASURES

Respiratory-swallow phase pattern, Modified Barium Swallow Impairment Profile (MBSImP) scores, Penetration-Aspiration Scale (PAS) scores, and MD Anderson Dysphagia Inventory scores.

RESULTS

Using visual feedback, patients were trained to initiate swallows during the midexpiratory phase of quiet breathing and continue to expire after swallowing. This optimal phase patterning increased significantly after treatment (P<.0001). Changes in respiratory-swallowing coordination were associated with improvements in 3 MBSImP component scores: laryngeal vestibular closure (P=.0004), tongue base retraction (P<.0001), and pharyngeal residue (P=.01). Significant improvements were also seen in PAS scores (P<.0001). Relative to pretreatment values, patients participating in 1-month follow-up had increased optimal phase patterning (P<.0001), improved laryngeal vestibular closure (P=.01), tongue base retraction (P=.003), and pharyngeal residue (P=.006) MBSImP scores and improved PAS scores (P<.0001).

CONCLUSIONS

Improvements in respiratory-swallowing coordination can be trained using a systematic protocol and respiratory phase-lung volume-related biofeedback in patients with HNC and chronic dysphagia, with favorable effects on airway protection and bolus clearance.

Electrophysiological evaluation of oropharyngeal Dysphagia in Parkinson's disease

Parkinson’s disease (PD) is a chronic, neurodegenerative movement disorder that typically affects elderly patients. Swallowing disorders are highly prevalent in PD and can have grave consequences, including pneumonia, malnutrition, dehydration and mortality. Neurogenic dysphagia in PD can manifest with both overt clinical symptoms or silent dysphagia. Regardless, early diagnosis and objective follow-up of dysphagia in PD is crucial for timely and appropriate care for these patients. In this review, we provide a comprehensive summary of the electrophysiological methods that can be used to objectively evaluate dysphagia in PD. We discuss the electrophysiological abnormalities that can be observed in PD, their clinical correlates and the pathophysiology underlying these findings.

Aging-related changes in swallowing, and in the coordination of swallowing and respiration determined by novel non-invasive measurement techniques

AIM

Previous studies have shown that the process of swallowing changes with aging, a phenomenon known as presbyphagia. These subtle and subclinical age-related changes make older adults more vulnerable to dysphagia during disease insults. However, there are limited studies of the swallowing process in older adults, because measurements are typically invasive or require exposure to X-rays. In the present study, we used integrated non-invasive measurements to determine aging-related changes of swallowing, and in the coordination of swallowing and respiration for a population of healthy participants.

METHODS

The non-invasive system provided measurements of larynx movement with piezoelectric sensors, submental muscle activity with surface electromyography and respiration-swallowing coordination by measurement of nasal airflow. We recruited 112 healthy participants from the community, 35 in a young-age group (age 20-30 years), 38 in a middle-age group (age 31-50 years) and 39 in an old-age group (age 51-70 years).

RESULTS

The oropharyngeal swallowing parameters of the old-age group had delayed onset latency and longer swallowing apnea duration relative to the other groups, and these differences were greater for larger boluses. The middle- and old-age groups had less expiratory-expiratory respiratory phase pattern than the young-age group. The probability of piecemeal deglutition was highest in the old-age group and lowest in the young-age group. These results show that the phases of oropharyngeal swallowing and the coordination of swallowing with respiration gradually change with aging.

CONCLUSIONS

We used integrated non-invasive measurements to document age-related changes in swallowing, and in the coordination of swallowing and respiration in healthy adults.

The interaction between breathing and swallowing in healthy individuals

In this article, we aimed at investigating the interaction between breathing and swallowing patterns in normal subjects. Ten healthy volunteers were included in the study. Diaphragm EMG activity was recorded by a needle electrode inserted into the 7th or 8th intercostal space. Swallowing was monitored by submental EMG activity, and laryngeal vertical movement was recorded by using a movement sensor. A single voluntary swallow was initiated during either the inspiration or expiration phases of respiration, and changes in EMG activity were evaluated. When a swallow coincided with either inspiration or expiration, the duration of the respiratory phase was prolonged. Normal subjects were able to voluntarily swallow during inspiration. During the inspiration phase with swallowing, diaphragmatic activity did not ceased and during the expiration phase with swallowing, there was a muscle activity in the diaphragm muscle.

Respiratory-swallowing coordination and swallowing safety in patients with Parkinson's disease

The purpose of this study was to determine if individuals with Parkinson's disease (PD) demonstrate abnormal respiratory events when swallowing thin liquids. In addition, this study sought to define associations between respiratory events, swallowing apnea duration, and penetration-aspiration (P-A) scale scores. Thirty-nine individuals with PD were administered ten trials of a 5-ml thin liquid bolus. P-A scale score quantified the presence of penetration and aspiration during the swallowing of a 3-oz sequential bolus. Participants were divided into two groups based on swallowing safety judged during the 3-oz sequential swallowing: Group 1 = P-A ≤ 2; Group 2 = P-A ≥ 3. Swallows were examined using videofluoroscopy coupled with a nasal cannula to record respiratory signals during the event(s). Findings indicated that expiration was the predominant respiratory event before and after swallowing apnea. The data revealed no differences in our cohort versus the percentages of post-swallowing events reported in the literature for healthy adults. In addition, individuals with decreased swallowing safety, as measured by the P-A scale, were more likely to inspire after swallows and to have shorter swallowing apnea duration. Individuals who inspired before swallow also had longer swallowing apnea duration. The occurrence of inspiratory events after a swallow and the occurrence of shorter swallowing apnea durations may serve as important indicators during clinical swallowing assessments in patients at risk for penetration or aspiration with PD.

Respiratory-swallow phase patterns and their relationship to swallowing impairment in patients treated for oropharyngeal cancer

BACKGROUND

Unstable respiratory-swallowing coordination has been associated with disorders and disease. The goals of this study were (1) to describe respiratory-swallow patterns in patients with dysphagia consequent to treatments for cancers of the oropharynx and (2) to determine the association between respiratory-swallow patterns, airway invasion, and overall severity of swallowing impairment.

METHODS

This prospective, cross-sectional design compared respiratory-swallow patterns in 20 patients treated for oropharyngeal cancer and 20 healthy, age-matched control participants. Nasal airflow direction was synchronously recorded with videofluoroscopic imaging in participants who swallowed 5-mL thin liquid barium boluses.

RESULTS

Respiratory-swallow patterns differed between groups. Most control participants initiated and completed swallowing bracketed by expiratory airflow. Swallowing in patients often interrupted inspiratory flow and was associated with penetration or aspiration of the bolus.

CONCLUSIONS

We suggest nonexpiratory bracketed respiratory-swallowing phase patterns in patients with oropharyngeal cancer may place patients at greater risk of airway penetration or aspiration during swallowing.

Coordination of respiration and swallowing: functional pattern and relevance of vocal folds closure

CONTEXT: Breathing and swallowing coordination, despite the expressive number of study, remain as theme deserving further research. OBJECTIVE: To identify a coordination pattern between swallowing and the natural breathing pause that occur in association with it (swallowing apnea) and also the relevance of the vocal folds closure in this process. METHODS: Sixty-six adults, male and female, including normal health people, post-laryngectomy individuals and patients with digestive complaints without dysphagia were analyzed. The respiratory air flux interruptions produced by wet requested swallows and dry, requested and spontaneous swallows, were registered using thermo and piezoelectric receptors coupled to synectics medical manometry equipment, using Polygram upper 4.21 software. The results were analyzed with the Chi-square (3×2) and (2×2) nonparametric independency test with P = 0.05. RESULTS: Swallowing apnea is a preventive breathing stop that start just before and stay present during all deglutition pharyngeal phase. It is a well coordinated phenomena that occur as pattern in association with low elastic resistance of the lung, on the expiratory final phase until inspiration initial phase. This breathing stoppage it is usually followed by a short expiraton preceding a new breathing cycle. The swallow apnea and vocal folds closure are both independents mechanisms. CONCLUSION: It is possible to suppose that in the subconscious condition, swallowing apnea is integrated under coordination of the same control mechanism that also involves the elastic resistance of the lung.

Abnormal swallowing reflex and COPD exacerbations

BACKGROUND

It is unclear whether an abnormal swallowing reflex affects COPD exacerbations. This study investigated the prevalence of abnormal swallowing reflexes and its relationship with COPD exacerbation prospectively. We also clarified its association with gastroesophageal reflux disease (GERD) and airway bacterial colonization.

METHODS

Swallowing reflex and serum C-reactive protein (CRP) levels were examined in subjects with stable COPD and in control subjects. Concurrently, GERD symptoms were assessed using a self-reported questionnaire, and sputum bacterial cultures were investigated in the same subjects. Exacerbations were counted prospectively during the following 12 months.

RESULTS

The study group comprised 67 subjects with COPD and 19 controls. The prevalence of abnormal swallowing reflex was significantly higher in subjects with COPD (22/67) than controls (1/19; P = .02). Among subjects with COPD, the serum CRP level, GERD symptoms, isolation of sputum bacteria, and the frequency of exacerbations were significantly increased in those with abnormal swallowing reflexes compared with controls (2.72 vs 1.04 mg/L, P = .04, for serum CRP level; 6.75 vs 4.10 points, P = .04, for GERD symptoms; 5/11 vs 3/22, P = .04, for the isolation of sputum bacteria; and 2.82 vs 1.56/y, P = .007, for the annual frequency of exacerbations). Multivariable analysis confirmed that abnormal swallowing reflex was significantly associated with frequent exacerbations (>or= 3/y; P = 0.01).

CONCLUSIONS

Abnormal swallowing reflexes frequently occurred in subjects with COPD and predisposed them to exacerbations. Abnormal swallowing reflexes in COPD might be affected by the comorbidity of GERD, and cause bacterial colonization.

Coordination of Mastication, Swallowing and Breathing

The pathways for air and food cross in the pharynx. In breathing, air may flow through either the nose or the mouth, it always flows through the pharynx. During swallowing, the pharynx changes from an airway to a food channel. The pharynx is isolated from the nasal cavity and lower airway by velopharyngeal and laryngeal closure during the pharyngeal swallow. During mastication, the food bolus accumulates in the pharynx prior to swallow initiation. The structures in the oral cavity, pharynx and larynx serve multiple functions in breathing, speaking, mastication and swallowing. Thus, the fine temporal coordination of feeding among breathing, mastication and swallowing is essential to provide proper food nutrition and to prevent pulmonary aspiration. This review paper will review the temporo-spatial coordination of the movements of oral, pharyngeal, and laryngeal structures during mastication and swallowing, and temporal coordination between breathing, mastication, and swallowing.

Lung volume during swallowing: single bolus swallows in healthy young adults

PURPOSE

This study examined the relationship between swallowing and lung volume initiation in healthy adults during single swallows of boluses differing in volume and consistency. Differences in lung volume according to respiratory phase surrounding the swallow were also assessed.

METHOD

Nine men and 11 women between the ages of 19 and 28 years served as study participants. Lung volume and respiratory phase data were recorded as each participant completed 5 trials each of 10-mL and 20-mL water boluses by cup, and thin and thick paste boluses by spoon, presented in randomized order.

RESULTS

Significant differences in lung volume at swallow initiation were found based on bolus consistency but not on bolus volume. No differences were found for lung volume initiation based on the respiratory phase surrounding the swallow or for the respiratory pattern based on bolus volume or consistency.

CONCLUSION

Findings of this study extend the existing knowledge base regarding the interaction of the swallow and respiratory systems by identifying targeted lung volumes at swallow initiation. In addition to other swallow-related biomechanical events and respiratory phase relationships surrounding a swallow, the lung volume at swallow initiation may be an important consideration when investigating swallow physiology and physiopathy.

[Prolonged apnea/hypopnea during water swallowing in patients with amyotrophic lateral sclerosis]

PURPOSE

Swallowing difficulty is increased along with progression of respiratory disturbance in patients with Amyotrophic Lateral Scalerosis (ALS). To analyze the respiratory patterns during swallowing is important for the management of this disease. In this study, we evaluated apnea/hypopnea during water swallowing and the respiratory cycle at rest and after water swallowing.

METHOD

We evaluated respiratory patterns in swallowing in 10 ALS patients (66.0 +/- 7.1 years old), in 10 Myotonic dystrophy (MD) patients (46.5 +/- 12.2 years old), and in 10 healthy volunteers as control subjects (61.7 +/- 10.0 years old). The ALS and MD patients had consulted the Department of Neurology of Toneyama National Hospital or Tokushima National Hospital between April 2002 and July 2006. Respiratory patterns were evaluated by simultaneous recording of cervical swallowing sound in water swallow. A hypersensitive microphone measured cervical sound. A thermister was used for pneumography. The means of four continuous respiratory cycles at rest and after swallow of 3 ml water were used for analysis. Respiration with amplitude of 1/2 or smaller than that of the pneumography at rest was defined as hypopnea, and the apnea/hypopnea duration was evaluated as the respiratory suppression time.

STATISTICAL ANALYSIS

All analyses were performed using SPSS 11.0J (SPSS Inc., Chicago, IL).

RESULTS

In the ALS group, the respiratory cycle was 3.15 +/- 0.76 sec (2.31-4.39 sec) at rest, while after swallowing, it was 2.78 +/- 0.83 sec (1.77-4.80 sec) (p = 0.1). In the MD group, the respiratory cycle was 2.56 +/- 0.46 sec (1.91-3.67 sec) at rest, while after swallowing, it was 2.94 +/- 0.60 sec (2.03-4.29 sec). In the control group, it was 3.46 +/- 0.57 sec (3.18-4.34 sec) at rest and 3.24 +/- 0.50 sec (2.64-4.04 sec) after swallowing. The apnea/hypopnea duration during water swallow was 14.33 +/- 8.89 sec (2.50-30.68 sec) in the ALS group, 3.66 +/- 1.58 sec (1.78-6.42 sec) in the MD group, and 3.64 +/- 1.00 sec (2.34-5.56 sec) in the control group. The apnea/hypopnea duration in the ALS group was significantly longer than that in MD and control groups (p = 0.005, p = 0.004 by the t-test). The ALS patients with severe respiratory failure or with aspiration in videofuoroscopy showed extended apnea/hypopnea duration.

CONCLUSION

Prolonged apnea/hypopnea was observed during water swallowing in ALS patients. We speculate that this prolongation is caused by severe swallowing disturbance and respiratory failure, which increases the risk of aspiration. The respiration of ALS patients should be closely monitored during eating.

[Efficacy of rehabilitation in oropharyngeal dysphagia]

BACKGROUND

efficacy of rehabilitation in oropharyngeal dysphagia. In our country the practice of speech-language pathology in oropharyngeal dysphagia has increased significantly and, at this moment, deserves attention since practice needs to be based on scientific evidence. Therapeutic techniques and the outcome of rehabilitation in oropharyngeal dysphagia have been studied since the 70s, reaching its high point during the 80s and 90s. Few studies have investigated the efficacy of therapy in the rehabilitation of oropharyngeal dysphagia, the vast majority have tried to prove the effects of therapy on the dynamics of swallowing. In Brazil, the studies about oropharyngeal dysphagia have, in great part, investigated assessment procedures, and only a few have worried about rehabilitation.

AIM

to present a critical analysis about the efficacy of rehabilitation in oropharyngeal dysphagia.

CONCLUSION

this review of the literature indicates that non-randomized studies have compromised the results, once the casuistic of the researches are very heterogeneous--they include neurogenic and mechanical oropharyngeal dyshagia caused by different etiologies. Besides that, therapeutic programs which are used are not sufficiently described, compromising the reproduction of the methodology by other researchers. These results suggest the need for more randomized studies, which can be initially developed as case studies in order to exclude the control variables of therapy efficacy. Another suggestion is, as proposed by present researches, to use scales that can measure the impact of swallowing training in the nutritional and pulmonary condition of dysphagic patients. An important research area, related to the control of therapeutic efficacy and efficiency, are the studies that aim to establish the decrease in hospital and home care costs as a consequence of speech-language intervention with patients with oropharyngeal dyspahgia.

Respiration during feeding on solid food: alterations in breathing during mastication, pharyngeal bolus aggregation, and swallowing

During feeding, solid food is chewed and propelled to the oropharynx, where the bolus gradually aggregates while the larynx remains open and breathing continues. The aggregated bolus in the valleculae is exposed to respiratory airflow, yet aspiration is rare in healthy individuals. The mechanism for preventing aspiration during bolus aggregation is unclear. One possibility is that alterations in the pattern of respiration during feeding could help prevent inhalation of food from the pharynx. We hypothesized that respiration was inhibited during bolus aggregation in the valleculae. Videofluorography was performed on 10 healthy volunteers eating solid foods with barium. Respiration was monitored concurrently with plethysmography and nasal air pressure. The timing of events during mastication, food transport, pharyngeal bolus aggregation, and swallowing were measured in relation to respiration. Respiratory cycle duration decreased during chewing (P < 0.001) but increased with swallowing (P < 0.001). During 66 recordings of vallecular bolus aggregation, there was inspiration in 8%, expiration in 41%, a pause in breathing in 17%, and multiple phases (including inspiration) in 35%. Out of 98 swallows, 47% started in the expiratory phase and 50% started during a pause in breathing, irrespective of bolus aggregation in the valleculae. Plethysmography was better than nasal manometry for determining the end of active expiration during feeding and swallowing with solid food. The hypothesis is rejected in that respiration was not inhibited during bolus aggregation. These findings suggest that airflow through the pharynx does not have a role in preventing aspiration during bolus aggregation in the oropharynx.

The First Year of Human Life: Coordinating Respiration and Nutritive Swallowing

This study provides the first documented report of the maturation of breathing-swallowing coordination during feeding in ten healthy term human infants through the first year of life. A total of 15,073 swallows were obtained across ten assessments between 48 h and 12 months of age. Midexpiratory swallows represented the dominant pattern of breathing-swallowing coordination within the first 48 h (mean = 45.4%), but the prevalence of this pattern declined rapidly in the first week to 29.1% (p = 0.012). Inspiratory-expiratory swallows increased with age (p < 0.001), particularly between 9 (37.0%) and 12 months (50.4%). Between 72.6% and 75.0% of swallows were followed by expiration in the latter 6 months, which is an adult-like characteristic. These data suggest that while postswallow expiration is a robust feature of breathing-swallowing coordination from birth, two major shifts in the precise patterns occur: the first after 1 week of postnatal feeding experience and the second between 6 and 12 months, most likely due to neural and anatomical maturation.

Effect of reclining and chin-tuck position on the coordination between respiration and swallowing

Chin-tuck position and reclining posture have been used in dysphagia patients to prevent aspiration during swallowing. However, both behavioural treatments may affect respiratory function. This study was carried out to test the hypothesis that if chin-tuck posture and body reclining affected respiratory function, this would be associated with altered coordination between respiration and swallowing. To investigate this hypothesis, respiratory parameters and manometry were used in each of four combinations of reclining posture and chin-tuck position. In the 60 degrees reclining with 60 degrees chin-tuck position, duration of swallowing apnea (0.89 s.d. 0.17 s) and submental electromyography burst (2.34 s.d. 0.84 s) were significantly longer when compared to both upright sitting and 30 degrees reclining positions. We conclude that 60 degrees reclining from vertical with 60 degrees chin-tuck may affect oral processing stages which delay and reduce a variety of oropharyngeal movements. These in turn significantly influence the coordination between respiration and swallowing.

Use of respiratory inductance plethysmography for the detection of swallowing in the elderly

It is essential to have a user-friendly, noninvasive bedside procedure at our disposal in order to study swallowing and swallowing disorders in the elderly in view of the frailty of this age group. In the present work, respiratory inductance plethysmography (RIP) is proposed as an appropriate clinical tool for such studies. An automated process for the detection of swallowing is used involving the derivative of the respiratory volume signal. The accuracy of the automated detection is given by the area under the Receiver Operating Characteristic (ROC) curve and is found to be greater than 0.9. At the optimal threshold, RIP constitutes a reliable and objective bedside clinical tool for studying swallowing in the elderly, as well as being user-friendly and noninvasive. In addition, RIP can be used to monitor swallowing in order to analyze swallowing disorders and put in place medical supervision of swallowing for individuals who might aspirate.

Direct Measurement of Subglottic Air Pressure While Swallowing

OBJECTIVE

The subglottic pressure theory for swallowing asserts that laryngeal mechanoreceptors have a role in the regulation of swallowing function. The primary purpose of this study was to determine if subglottic air pressure is generated during swallowing in a healthy, nontracheostomized person.

METHODS

This pilot investigation used a prospective, repeated-measures design in a single subject. Direct measurement of subglottic air pressure was obtained through percutaneous puncture of the cricothyroid membrane. Swallows were timed with four randomly assigned lung volumes: total lung capacity, tidal volume, functional residual capacity (FRC), and residual volume.

RESULTS

Lung volumes above FRC generated positive subglottic pressure during the swallow, whereas lung volumes below FRC generated consistently negative subglottic pressures. The degree and polarity of the pressure was directly related to lung volume at the time of the swallow.

CONCLUSION

These findings illustrate that during normal swallowing, positive subglottic air pressure is likely present. Previously, subglottic air pressure during swallowing had been measured in tracheostomy patients only.

The effect of viscosity on the breath-swallow pattern of young people with cerebral palsy

In this observational pilot study, we investigated the effect of swallowing pudding and liquids of different viscosity on the breath-swallow pattern of young people with quadriparetic cerebral palsy (CP) and normal controls. A noninvasive acoustical technique was used to monitor breaths and swallows while the individuals were drinking thin and thick liquids and consuming pudding. The results showed that subjects with CP had a significantly higher rate of post-swallow inspiration than controls when they were drinking thin liquid but not when they were consuming thick liquid or pudding. Subjects with CP had greater variability and duration of deglutition apnea than controls. Whether the differences seen in breath-swallow pattern and deglutition apnea in young people with CP contribute to aspiration risk remains to be determined. Further clarification of these results by a carefully controlled study of individuals with cerebral palsy undergoing concurrent videofluoroscopic swallowing evaluation and acoustical monitoring of the breath-swallow pattern is required to verify these preliminary results and assess their clinical applicability.

Effects of viscosity, taste, and bolus volume on swallowing apnea duration of normal adults

OBJECTIVE

The effects of viscosity, taste, and nectar-thick liquid bolus volume on swallowing apnea duration (SAD) were examined.

STUDY DESIGN AND SETTING

Twenty-two adults, comprised of 10 males and 12 females, participated. SAD was assessed via nasal airflow during swallow conditions of viscosity (thin liquid, thick liquid, and puree), taste (water, apple juice, lemon concentrate), and nectar-thick liquid bolus volumes (5, 10, 15, and 20 mL) across three trials.

RESULTS

A significant main effect of nectar-thick liquid bolus volume was found (P < 0.05). Viscosity and taste were not significant.

CONCLUSIONS

SAD increased with increases in bolus volume; however, neither changes in bolus viscosity nor changes in taste affected SAD.

SIGNIFICANCE

These findings indicate that since viscosity was not significant, the normative data previously published (by this PI) with 60 healthy adults stratified by age and gender can be utilized for comparison to disordered swallowing without regard to the bolus viscosity being used.

EBM RATING

D.

Bolus location associated with videofluoroscopic and respirodeglutometric events

The purpose of the present investigation was to determine the relation between specific events observed with simultaneous videofluoroscopy and respirodeglutometry. The order of occurrence was determined for each of 31 events (18 videofluoroscopic, 13 respirodeglutometric). Using 1 video frame (33.3 ms) as the maximum distance allowed between the average times of 2 events in the same cluster, 8 potential clusters were identified, 3 of which were statistically confirmed based on 90% confidence intervals on the mean time distances between events. Confirmed clusters included the time of (a) complete velar descent and the onset of the small noninspiratory flow (SNIF), (b) full separation of the base of the tongue from the pharyngeal wall and SNIF nadir, complete upper esophageal sphincter closure, and SNIF nadir, and (c) onset of epiglottic return and apnea offset. The onset of respiratory flow occurred within 13 ms after the onset of epiglottic return. Additionally, the percentage of swallows during which the bolus head or tail was located at each of 6 locations was determined for 20 of these events (10 videofluoroscopic, 10 respirodeglutometric). The 6 locations of interest included the oral cavity, base of tongue, valleculae, pyriform sinuses, upper esophageal sphincter, and the esophagus. Lastly, of the 72 swallows performed by these healthy, young adults, 65 (90.3%) were preceded by expiration, and all (100%) were followed by expiration.

Effects of age, gender, bolus volume, bolus viscosity, and gustation on swallowing apnea onset relative to lingual bolus propulsion onset in normal adults

The purpose of this study was to ascertain the normal relation of swallowing apnea (SA) onset relative to lingual bolus propulsion along with factors that may alter this relation. Forty adults, composed of 10 men and 10 women in each of 2 age groups (i.e., 20-30 and 63-79 years) participated. SA onset was assessed during 5- and 20-ml bolus volumes of water and apple juice across 3 trials. The effects of age, gender, bolus volume, bolus viscosity, and gustation on SA onset relative to lingual bolus propulsion were examined. A significant interaction of Age x Gender x Volume was found. In general, older adults initiated SA onset earlier than young adults, and large boluses elicited an earlier SA onset than small boluses regardless of group. Young men demonstrated significantly later SA onset than the older men for large volumes; this difference was not observed for small volumes, nor was it found between young and older women. SA onset also was assessed during 5-ml bolus volumes of thin apple juice, thick apple juice, and applesauce across three trials. A significant main effect of viscosity was found revealing that SA onset was initiated later as bolus viscosity increased. Thus, the results of this investigation provided data on the relation of SA onset relative to lingual bolus propulsion in individuals with normal swallowing and how this relation changes as a function of age, gender, bolus volume, bolus viscosity, and gustation.

Clinical implications of gastroesophageal reflux disease and swallowing dysfunction in COPD

The intimate anatomical and physiologic relationship between the upper airway and esophagus consists of complex interactions between various muscles and nerves with both voluntary and involuntary patterns of control. Alterations in this harmonic relationship can lead to swallowing abnormalities ranging from dysphagia to gross aspiration, gastroesophageal reflux disease (GERD) and chronic cough. There is a paucity of data regarding pathologic alterations in the upper airway-esophageal relationship in patients with COPD. The association between GERD and respiratory symptoms is well recognized in the setting of asthma; however, the nature of this relationship remains controversial. The association of GERD and COPD is even less clear. A review of the limited data on GERD and swallowing abnormalities in patients with COPD indicate that prevalence of GERD and esophageal disorders in patients with COPD is higher than in the normal population. However, its contribution to respiratory symptoms, bronchodilator use and pulmonary function in patients with COPD remains unknown. Although dysphagia and swallowing dysfunction on videofluoroscopic swallow evaluation are common in patients with COPD, their role as exacerbators of COPD remains to be elucidated. Further clinical research is necessary to evaluate the role of GERD and swallowing dysfunction in both stable and acute exacerbation of COPD.