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Outcomes from studying the coordinative relationship between respiratory and swallow subsystems are inconsistent for sequential swallows, and the lung volume at the initiation of sequential swallowing remains undefined. The first goal of this study was to quantify the lung volume at initiation of sequential swallowing ingestion cycles and to identi...
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Tongue-hold swallow (THS) is a therapeutic maneuver used to increase the posterior pharyngeal wall motion during swallowing. This maneuver has also been reported to result in increased activation of the suprahyoid muscles. The hypothesis of this study was that the degree of suprahyoid muscle activation would depend on the tongue protrusion-length....
Citations
... Previous studies have demonstrated bolus (volume, viscosity) effects on the respiratory-swallow phase patterning (Hopkins- Rossabi et al., 2019;Lederle et al., 2012). In agreement with previous studies, we observed an effect of bolus volume on respiratory-swallow phase patterning, with decreased frequency of E-E patterning observed for sequential liquid tasks (thin and nectar-thickened liquid) compared to the cup and teaspoon liquid tasks (Dozier et al., 2006;Hopkins-Rossabi et al., 2019;Wheeler Hegland et al., 2011). Furthermore, there was a decreased frequency of E-E patterning for sequential thin liquid task in the ALS group compared to the healthy group. ...
Purpose
Amyotrophic lateral sclerosis (ALS) impacts bulbar and respiratory musculature, which may contribute to impaired swallow function (dysphagia) and respiratory–swallow coordination. The purpose of this pilot study was to examine if respiratory–swallow coordination in individuals with ALS was perturbed compared to healthy controls. We further explored relationships between measures of respiratory function and self-reported swallowing outcomes on respiratory–swallow coordination.
Method
We employed a cross-sectional design with eight participants with ALS and eight age- and sex-matched healthy participants. Respiratory inductance plethysmography and a nasal cannula were used to capture respiratory–swallow phase patterns during a standardized clinical swallow examination. The advantageous respiratory–swallow phase pattern was defined if exhalation surrounded the swallow (E–E). Spirometry was used to capture indices of respiratory function (forced vital capacity % predicted, peak cough flow [PCF]). Validated questionnaires were used to collect information regarding ALS-related bulbar functional status and swallowing-related concerns.
Results
Compared to the matched healthy cohort, individuals with ALS demonstrated higher rates of non–E-E respiratory–swallow phase patterning and worse bulbar/swallow dysfunction. Group (ALS), swallow tasks, and PCF were significantly associated with respiratory–swallow phase pattern.
Conclusions
These preliminary findings support altered respiratory–swallow phase patterning in ALS. Future work should employ an instrumental assessment to quantify swallowing physiology and elucidate the relationship between perturbed respiratory–swallow coordination and swallowing function.
... Third, initiating swallows within the mid-lung volume range and exhaling immediately after the swallow are thought to promote both a more coordinated and efficient pressure gradient within the pharynx and esophagus during bolus transit (Gross, 2014;Irvin et al., 1984;McFarland et al., 2018;Paydarfar & Buerkel, 1995). Lastly, lung volume initiation has been found to influence deglutitive subglottic pressure generation (Gross, Atwood, et al., 2003;Gross et al., 2006Gross et al., , 2012Shaker et al., 2002;Shin et al., 1988), respiratory-phase patterning (Drulia, 2016;Kijima et al., 2000;Wheeler Hegland et al., 2011;Yagi et al., 2017), laryngeal elevation (Iwarsson et al., 1996;Iwarsson & Sundberg, 1998;Milstein, 1999;Mitchinson & Yoffey, 1947;Pabst & Sundberg, 1993), and the extent and duration of upper and lower esophageal segment openings (Mittal et al., 1987(Mittal et al., , 1988. ...
... Third, a syringe was used for all held swallows, whereas a medicine cup was used for the nonheld swallows. It is possible that differences in bolus delivery method between the two swallowing tasks may have impacted findings from this study-though the effects of bolus delivery method on respiratory phase patterning remains equivocal (Hirst et al., 2002;Hiss et al., 2001;Hopkins-Rossabi et al., 2019;Krishnan et al., 2020;Preiksaitis & Mills, 1996;Wheeler Hegland et al., 2011). Additionally, because of the long duration of bolus holding during the held swallowing task (approximately 6.5 s), we believe the effect of bolus delivery method on RSC (if present) was negligible. ...
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.
... However, the findings of these animal studies are not comparable to the results of this study because the animals were anesthetized and did not control the rhythmicity or swallowing movements by themselves. Numerous previous studies have investigated how sequential swallowing affects respiration pre-and postswallowing in humans (Dozier et al., 2006;Daniels et al., 2007;Wheeler Hegland et al., 2011;Lederle et al., 2012). However, the respiratory pattern at pre-and post-swallowing has varied between previous studies. ...
... However, the respiratory pattern at pre-and post-swallowing has varied between previous studies. For example, the percentage of occurrence of the expiratory phase immediately before and after sequential swallowing (i.e., the EE type) was reported to be 33% for 100 ml (Wheeler Hegland et al., 2011) and 38.6% for 50 ml (Dozier et al., 2006), while it was 52.4% (11/21 participants) in this study. ...
Examining the coordination of respiration and swallowing is important for elucidating the mechanisms underlying these functions and assessing how respiration is linked to swallowing impairment in dysphagic patients. In this study, we assessed the coordination of respiration and swallowing to clarify how voluntary swallowing is coordinated with respiration and how mastication modulates the coordination of respiration and swallowing in healthy humans. Twenty-one healthy volunteers participated in three experiments. The participants were asked to swallow 3 ml of water with or without a cue, to drink 100 ml of water using a cup without breathing between swallows, and to eat a 4-g portion of corned beef. The major coordination pattern of respiration and swallowing was expiration–swallow–expiration (EE type) while swallowing 3 ml of water either with or without a cue, swallowing 100 ml of water, and chewing. Although cueing did not affect swallowing movements, the expiratory time was lengthened with the cue. During 100-ml water swallowing, the respiratory cycle time and expiratory time immediately before swallowing were significantly shorter compared with during and after swallowing, whereas the inspiratory time did not differ throughout the recording period. During chewing, the respiratory cycle time was decreased in a time-dependent manner, probably because of metabolic demand. The coordination of the two functions is maintained not only in voluntary swallowing but also in involuntary swallowing during chewing. Understanding the mechanisms underlying respiration and swallowing is important for evaluating how coordination affects physiological swallowing in dysphagic patients.
... Swallow preferentially occurs within the tidal volume range, has a preference for the expiratory (E) phase of breathing (10,14,64,(126)(127)(128)(129), and is in part mediated by pulmonary stretch receptors and airway proprioceptor spinal afferents (9). Swallow during the inspiratory phase risks aspiration of material into the lungs, and swallow or laryngeal afferent stimulation can terminate inspiration by inhibiting inspiratory neurons or by activating postinspiratory (post-I) neurons in the VRC (130,131), not unlike the inspiratory Hering-Breuer reflex. ...
Swallow is a primitive behavior regulated by medullary networks, responsible for movement of food/liquid from the oral cavity to the esophagus. To investigate how functionally heterogeneous networks along the medullary intermediate reticular formation (IRt) and ventral respiratory column (VRC) control swallow, we electrically stimulated the nucleus tractus solitarius to induce fictive swallow between inspiratory bursts, with concurrent optical recordings using a synthetic Ca ²⁺ indicator in the sagittally-sectioned rat hindbrain preparation (SSRH). Simultaneous recordings from hypoglossal nerve rootlet (XIIn) and ventral cervical spinal root C1-C2 enabled identification of the system-level correlates of A) swallow (identified as activation of the XIIn but not the cervical root), and B) Breuer-Hering expiratory reflex (BHE: lengthened E in response to stimuli during E). Optical recording revealed reconfiguration of respiration-modulated networks in the ventrolateral medulla during swallow and the BHE reflex. Recordings identified novel spatially compact networks in the IRt near the facial nucleus (VIIn) that were active during fictive swallow, suggesting that the swallow network is not restricted to the caudal medulla. These findings also establish the utility of using this in vitro preparation to investigate how functionally heterogeneous medullary networks interact and reconfigure to enable a repertoire of orofacial behaviors.
... A recent systematic review and meta-analysis by Hopkins-Rossabi et al. [37] provided strong evidence of predominant expiratory phase bracketing that varied significantly with bolus volume. Preliminary evidences suggest that bolus volume [21,27,[37][38][39], bolus consistency [38,40], taste [19], and type of ingestion [41,42] does influence duration of swallow-induced apnea and respiratory phases surrounding the apnea in various typical and atypical groups, but not without contradictory findings [43]. The heterogeneity in findings makes it difficult to draw generalizable conclusions. ...
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.
... Every participant was seated comfortably on a chair (with armrest and back support) with his/her foot placed on the floor. [17] Water quantity was gauzed using a handheld standard measuring cup and transferred to a 170 ml commercially available disposable cup, and the test participants held the cup in their preferred hand. The directions to the participants for swallowing were: "On my command, you have to continuously swallow the water at your natural pace without stopping in between and avoid any oral spillage." ...
Introduction: Water-swallowing test (WST) is a simple, economical bedside screening test practiced for early identification of risk for dysphagia (or swallowing impairment). However, there is no consensus on the right test quantity to assess swallowing ability by WST. Aim of the Study: The aim of the present study was to establish the right quantity of water for WST sufficient to assess sequential swallowing in healthy adults albeit avoiding larger quantity of thin liquids. Subjects and Methods: Thirty healthy young adults (HYA) (20-40 years) and thirty healthy middle-aged adults (HMA) (41-60 years) were enrolled by nonrandom convenient sampling. Four quantities (50, 90, 100, and 150 ml) of room temperature water was gauzed by a measuring cup and randomly presented to the participants to swallow in their natural pace. As per the test standard, volume/swallow (V/S), time/swallow (T/S), and swallow capacity (SC) indices were derived and subjected to further statistical analysis. Results: The results of the study suggested statistically significant increased V/S and SC in a lesser T/S among HYA compared to HMA, and the difference was at P < 0.05. The results also revealed 150 and 50 ml to have statistically significant highest and lowest SC, respectively, at P < 0.05. Pearson's correlation index suggested a positive correlation across swallowing indices between the four test volumes of water. Conclusion: The state of evidence suggests better swallowing performance in HYA, and also, there exists a direct relationship between the quantity of water and indices of WST. The advisory is to use the least of the four test quantity of thin liquids for the WST. © 2020 Wolters Kluwer Medknow Publications. All rights reserved.
... The possibility of spinal influences on swallow was supported by Sumi in 1963 [8], who reported that groups of medullary and spinal inspiratory and expiratory neurons were either excited or inhibited by swallow, even when the animals were paralyzed and artificially ventilated. These pivotal studies form a foundation for the swallow field, and since then swallow has been studied in vivo in the mouse [9], rat [10,11], bat [12], cat [13][14][15][16][17][18][19], rabbit [20,21], pig [22], sheep [23], goat [24], monkey [25,26], and human [27][28][29][30][31]. Swallow has also been studied in situ [19,[32][33][34] and in vitro [35] and modeled in silico [36,37]. ...
... Despite the progress that has been made in the last century to understand the complex behavior of swallow, our mechanistic understanding of this important behavior is relatively limited. Classically, swallow has been regarded as a brainstem-mediated behavior, but more recent studies have determined that afferent feedback is important in the coordination of swallow with breathing cycle [27,[29][30][31]. In the cat, swallow occurs in the late expiratory (E2) phase of the cough-breathing cycle [14], but upper abdominal laparotomy produces a significant shift of swallow to the inspiratory phase of the breathing cycle [46]. ...
... In the cat, swallow occurs in the late expiratory (E2) phase of the cough-breathing cycle [14], but upper abdominal laparotomy produces a significant shift of swallow to the inspiratory phase of the breathing cycle [46]. Several studies in the human demonstrate that-regardless if swallow occurs as single [29] or sequential events [30], with a thin or thick consistency bolus [29,31], or if the system is challenged to coordinate with cough epochs [27]-swallow occurs during a targeted lung volume of 45-65% of vital capacity [27,[29][30][31]. In a previous publication, we reported this and developed the concept of lung volume targeting, which can explain swallow occurrence across any phase of cough in the human [27]. ...
Swallow-breathing coordination is influenced by changes in lung volume, which is modulated by feedback from both vagal and spinal sensory afferents. The purpose of this study was to manipulate feedback from these afferents, with and without a simultaneous mechanical challenge (chest compression), in order to assess the influence of each sensory pathway on swallow in rats. We hypothesized that manipulation of afferent feedback would shift the occurrence of swallow toward the inspiratory phase of breathing. Afferent feedback was perturbed by lidocaine nebulization, extra-thoracic vagotomy, or lidocaine administration to the pleural space in sodium pentobarbital anesthetized rats (N = 43). These different afferent perturbations were performed both in control conditions (no chest compression), and with chest compression. Manipulating pulmonary stretch receptor-mediated volume feedback in male animals decreased swallow occurrence. Female rats appear to rely more on spinal afferent feedback, as swallow occurrence shifted to late expiration with chest compression and vagotomy or lidocaine injections. Results suggest that sex-specific mechanisms modulate swallow-breathing coordination, and that vagal feedback is inhibitory to swallow-related muscles, while spinal feedback from pleural afferents has excitatory effects. This study supports the theory that a balance of vagal and spinal afferent feedback is necessary to maintain an optimal swallow pattern and swallow-breathing coordination.
... These adaptive changes to RSC in people with head and neck cancer were associated with posttreatment improvements in laryngeal vestibule closure, tongue base retraction, bolus clearance, and airway protection [33]. Research in healthy adults has revealed that altering bolus volumes, bolus viscosities, and bolus delivery methods all have immediate effects on the frequency of pre-and postswallow inhalation [23,27,[34][35][36][37][38], lung volume initiation [25,26,38,39], and swallow apnea duration [23,34,36,37,[40][41][42]. ...
Respiratory-swallow coordination (RSC) is important for swallowing safety. Atypical RSC is common in Parkinson’s disease (PD) and is associated with the presence of dysphagia and aspiration. Verbal cueing is known to affect RSC in healthy adults, yet an understanding of its effect on RSC in PD is unknown. Therefore, the aims of this study were to: (1) assess the effects of verbal cueing on respiratory-swallow patterning, lung volume initiation, and swallow apnea duration in PD; and (2) determine when during tidal breathing verbal cues should be given in order to increase the likelihood of eliciting optimal RSC. People with PD were prospectively recruited for respiratory-swallowing assessments during cued and non-cued swallowing conditions. Non-cued trials consisted of swallowing in an unprompted fashion, while cued trials consisted of swallowing only once participants were verbally instructed. Verbal cues were given at four specific points during tidal breathing. Nonparametric tests were used to compare differences in patterning, lung volume, and swallow apnea duration between the cued and non-cued swallows. Twenty-five people with PD were enrolled, yielding an analysis of 375 swallows. Verbal cueing significantly affected respiratory-swallow patterning (p < 0.0005), lung volume initiation (p < 0.0005), and swallow apnea duration (p < 0.0005). The effects of verbal cueing on RSC differed significantly depending on when during tidal breathing verbal cues were given. Cues given at high tidal inhalation were most likely to elicit optimal RSC, while cues given at low tidal exhalation were the least likely to elicit optimal RSC. The results of this study demonstrate that verbal cueing significantly affects RSC in PD. Depending on when verbal cues are given during tidal breathing, RSC can become more safe and coordinated or more atypical and risky. Clinicians should be cognizant of these effects by avoiding verbal cues if attempting to evaluate normal RSC during swallowing evaluations and cueing for swallows at the time of high tidal inhalation when targeting more optimal RSC in PD.
... Sequential swallowing, defined as multiple swallows in rapid succession, is a daily event that makes it possible to drink large volumes of liquids quickly (12). Some authors have studied the relationship between respiration and swallowing during sequential swallowing in healthy human adults by determining the lung volume at swallow initiation and/or the respiratory pattern surrounding sequential swallows (6,12,25,26). Monitoring of human breathing during sequential swallowing was realized noninvasively by measuring direct flow (oral, nasal, or both oral and nasal airflow being monitored) or by measuring changes in inflation of the lung often called respiratory effort (focusing on movements of chest wall and abdomen) (24). Sequential swallowing events have been simultaneously described and/or identified by many techniques such as videofluoroscopy, electromyography, and acoustic analysis (25). ...
... Sequential swallowing events have been simultaneously described and/or identified by many techniques such as videofluoroscopy, electromyography, and acoustic analysis (25). It was shown that sequential swallows are initiated at higher lung volumes than those that are typically associated with tidal breathing (26). Moreover, during sequential swallowing, there is a succession of ingestion cycles (ICs) (6,26 (6,26). ...
... It was shown that sequential swallows are initiated at higher lung volumes than those that are typically associated with tidal breathing (26). Moreover, during sequential swallowing, there is a succession of ingestion cycles (ICs) (6,26 (6,26). However, when comparing sequential swallowing with single swallows, it seems that although it is possible for ICs preceded and followed by expiration to predominate during sequential swallowing, the frequency of this pattern always remains lower than the frequency of single and isolated swallows preceded and followed by expiration (6,12,26). ...
Sequential liquid swallowing is a common daily occurrence during which coordination of deglutition and breathing are highly regulated to avoid pulmonary aspiration and to maintain hematosis. We studied the effects of sequential water swallowing (SWS) at fixed swallowing rates and with regular succession of swallows on respiration in healthy subjects. Thirty-one normal adults (19 men, 12 women) with a mean age of 27.96 ± 3.68 yr were explored at rest and during SWS (at 12 and 24 swallows/min). Respiration was recorded by intranasal air pressure changes and timing of deglutition by an acoustic method. Oxygen saturation [arterial O2 saturation from pulse oximetry (
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)] was monitored with a finger probe. During SWS, we determined the respiratory phase (inspiration or expiration) before and after each ingestion cycle (IC; period of sustained apnea including 1 or more swallows). We also measured inspiratory time (TI), expiratory time (TE), respiratory cycle duration (TT), respiratory rate (RR) and
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at rest and during SWS. We showed that respiration was interrupted by sequential swallows determining a succession of ICs that were often preceded and followed by expiration. During SWS, TI decreased and TE increased compared with rest ( P < 0.01). However, TT, RR, and
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did not change. It seems that the preferential coupling of swallowing with expiration during SWS is favored by an increase in TE to ensure airway protection, although the repetitive swallows, RR, and
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were not altered during SWS. These data may be useful to study the effects of aging and pathological conditions on swallowing and breathing coordination during SWS. NEW & NOTEWORTHY Sequential water swallowing induces ingestion cycles that are often preceded and followed by expiration. Moreover, inspiratory time decreases and expiratory time increases during sequential swallowing compared with rest without changes in ventilatory cycle duration, respiratory rate, and oxygen saturation.
... Both animal and human studies have shown that swallows occur preferentially at phase-transitions of the respiratory and ventilatory cycle, i.e., inspiration to early-expiration (I-early Exp), early-expiration to late-expiration (early Exp-late Exp), and late-expiration to inspiration (late Exp-I) (Dick et al., 1993;Paydarfar and Buerkel, 1995;Ono et al., 1998). Swallows have also been reported to occur during inspiration, i.e., I-I or I-swallow, as well as to interrupt the inspiratory phase of breathing (interrupted-I swallow) (Feroah et al., 2002;Roberge et al., 2007;Wheeler Hegland et al., 2009;Bonis et al., 2011;Wheeler Hegland et al., 2011;Yagi et al., 2017). Overall, five types of swallow patterns have been proposed, including I-swallow, interrupted-I, I-Exp, early Exp-late Exp, and Exp-I, despite most single swallows occurring predominantly during the I-Exp and early Exp-late Exp phasetransitions (Martin-Harris et al., 2005). ...
Swallow-breathing coordination safeguards the lower airways from tracheal aspiration of bolus material as it moves through the pharynx into the esophagus. Impaired movements of the shared muscles or structures of the aerodigestive tract, or disruptions in the interaction of brainstem swallow and respiratory central pattern generators (CPGs) result in dysphagia. To maximize lower airway protection these CPGs integrate respiratory rhythm generation signals and vagal afferent feedback to synchronize swallow with breathing. Despite extensive study, the roles of central respiratory activity and vagal feedback from the lungs as key elements for effective swallow-breathing coordination remain unclear. The effect of altered timing of bronchopulmonary vagal afferent input on swallows triggered during electrical stimulation of the superior laryngeal nerves or by injection of water into the pharyngeal cavity was studied in decerebrate, paralyzed, and artificially ventilated cats. We observed two types of single swallows that produced distinct effects on central respiratory-rhythm across all conditions: post-inspiratory type swallows disrupted central-inspiratory activity without affecting expiration, whereas expiratory type swallows prolonged expiration without affecting central-inspiratory activity. Repetitive swallows observed during apnea reset the E2 phase of central respiration and produced facilitation of swallow motor output nerve burst durations. Moreover, swallow initiation was negatively modulated by vagal feedback and was reset by lung inflation. Collectively, these findings support a novel model of reciprocal inhibition between the swallow CPG and inspiratory or expiratory cells of the respiratory CPG where lung distension and phases of central respiratory activity represent a dual peripheral and central gating mechanism of swallow-breathing coordination.
