Respiratory-swallow Coordination Research Articles

Respiratory-Swallow Coordination and Its Relationship With Pharyngeal Residue, Penetration, and Aspiration in People With Parkinson's Disease.

Respiratory-swallow coordination (RSC) frequently changes in people with Parkinson's disease (PwPD). Little is known about how these changes relate to impairments in swallowing safety (penetration and aspiration) and efficiency (pharyngeal residue). Therefore, the aims of this study were to assess the relationships between RSC, pharyngeal residue, penetration, and aspiration in PwPD. Twenty-four PwPD were recruited to undergo simultaneous assessment of RSC, swallowing safety, and swallowing efficiency. RSC was assessed using respiratory inductive plethysmography and nasal airflow and included measurements of respiratory pause duration, respiratory phase patterning, and lung volume during swallowing. Swallowing safety and efficiency were assessed using flexible endoscopic evaluation of swallowing, analyzed using the Visual Analysis of Swallowing Efficiency and Safety, and included measurements of pharyngeal residue, penetration, and aspiration. All data were blindly analyzed, with 20% of the data repeated for interrater reliability assessment. Multilevel statistical models were used to examine the relationships between RSC and swallowing. A total of 812 swallows were analyzed from 24 participants. Only 33.4% of swallows exhibited the typical exhale-swallow-exhale pattern. Additionally, 95% of participants exhibited abnormal swallow function. More severe hypopharyngeal residue ratings were associated with inhaling before the swallow compared to exhaling before the swallow. Additionally, more severe events of penetration and aspiration were associated with (a) inhaling before the swallow compared to exhaling before the swallow, (b) inhaling after the swallow compared to exhaling after the swallow, and (c) longer swallow-related respiratory pause durations. Inhaling after the swallow exhibited the strongest relationship with impairments in swallowing safety when compared to all other RSC variables. RSC exhibited significant relationships with pharyngeal residue, penetration, and aspiration in these PwPD. Clinicians should attend to RSC when assessing swallowing in PwPD. Future research is needed to examine if training an exhale-swallow-exhale pattern can be used to improve disordered swallowing in PwPD. https://doi.org/10.23641/asha.27211770.

Measurement of respiratory-swallowing coordination using an oronasal facemask in healthy individuals.

Respiratory-swallowing coordination (RSC)is well established as an essential airway-protective mechanism. Previous studies have used nasal airflow and/or kinematic rib cage and abdominal measures to assess respiration surrounding swallowing, meaning that the direct influence of oral respiration on RSC remains unknown. This study used a partitioned oronasal facemask to compare respiratory phase patterns measured using isolated nasal airflow with those measured using combined oronasal airflow during non-ingestive and ingestive swallowing tasks. Twenty-four healthy individuals with no respiratory or swallowing disorders were assessed at rest and during cued dry, 10mL water, continuous drinking and cracker swallowing tasks. Respiratory phase patterns were determined for discrete swallows using the nasal and combined oronasal channels separately. There was variable agreement between respiratory phase patterns according to the nasal and oronasal channels across swallowing conditions. The frequency of exhale-swallow-exhale, inhale-swallow-exhale and exhale-swallow-inhale patterns increased by 2%-3% each with the addition of oral flow data to nasal data, whereas the prevalence of inhale-swallow-inhale and ambiguous patterns decreased. This suggests that estimates of respiratory phase patterns are altered minimally by inclusion of oral respiratory estimates in a healthy sample. There were several additional findings of note, including lower within-participant, within-session trial consistency (test-retest reliability) than expected, suggesting high variability in respiratory phase patterns across trials. Additionally, data showed evidence of swallowing non-respiratory flow at the beginning and end of the respiratory-swallowing pause, moving in both inward and outward directions, potentially expanding current understanding of swallowing non-respiratory flow. Further in-depth physiological investigations are required to improve understanding of these findings.

Respiratory-swallow patterning and oropharyngeal swallowing impairment in patients undergoing evaluation for lung transplant.

Although swallowing impairment is prevalent following lung transplantation, baseline respiratory and swallowing characteristics are often overlooked. Respiratory disease processes may predispose lung transplant candidates to altered respiratory-swallow patterning and swallowing impairment. This cross-sectional study included patients referred for a Modified Barium Swallow Study during lung transplant evaluation. Swallowing impairment was measured using the Modified Barium Swallow Impairment Profile and Penetration-Aspiration Scale. Respiratory plethysmographic signals synchronized with videofluoroscopy were analyzed to determine phase patterning, pause duration, and rate. Mixed-effects logistic regression was used to identify linkages between respiratory and swallowing measures. Fifty patients were included and demonstrated delayed swallow initiation (49/50), oral residue (37/50), incomplete pharyngoesophageal segment opening (35/50), and esophageal retention (43/50). Airway invasion occurred infrequently (10/50). Atypical respiratory patterning was significantly associated with impairment in pharyngeal swallow initiation (OR [95% CI] = 1.76 [1.16, 2.68], p = 0.009), laryngeal elevation (OR [95% CI] = 1.45 [1.01, 2.07], p = 0.044), and laryngeal vestibular closure (OR [95% CI] = 2.57 [1.48, 4.46], p < 0.001). Increased pause duration was associated with impaired initiation (OR [95% CI] = 2.24 [1.20, 4.16], p = 0.011), laryngeal elevation (OR [95% CI] = 1.18 [1.03, 1.36], p = 0.018), laryngeal closure (OR [95% CI] = 1.28 [1.9, 1.50], p = 0.003), and tongue base retraction (OR [95% CI] = 1.33 [1.13, 1.56], p < 0.001). Patients undergoing evaluation for lung transplant demonstrated impaired swallowing and phase patterning. Preliminary findings implicate the need for further evaluation of respiratory-swallow coordination and its potential role in swallowing impairment before and after lung transplantation.

Efficacy and Safety of "Vacuum Swallowing" Based on a Strong Negative Esophageal Pressure in Healthy Individuals.

Vacuum swallowing is a unique method for improving the pharyngeal passage of a bolus by creating subatmospheric negative pressure in the esophagus. However, whether healthy individuals and other patients with dysphagia can reproduce vacuum swallowing remains unclear. Therefore, this study aimed to assess whether healthy individuals verified using high-resolution manometry (HRM) could reproduce vacuum swallowing and evaluate its safety using a swallowing and breathing monitoring system (SBMS). Two healthy individuals who mastered vacuum swallowing taught this method to 12 healthy individuals, who performed normal and vacuum swallowing with 5 mL of water five times each. The minimum esophageal pressure and the maximum pressure of the lower esophageal sphincter (LES) were evaluated during each swallow using the HRM. Additionally, respiratory-swallowing coordination was evaluated using the SBMS. Ten individuals reproduced vacuum swallowing, and a total of 50 vacuum swallows were analyzed. The minimum esophageal pressure (-15.0 ± 4.9 vs. -46.6 ± 16.7 mmHg; P < 0.001) was significantly lower, and the maximum pressure of the LES (25.4 ± 37.7 vs. 159.5 ± 83.6 mmHg; P < 0.001) was significantly higher during vacuum swallowing. The frequencies of the I-SW and SW-I patterns in vacuum swallowing were 38.9% and 0%, respectively, using the SBMS. Vacuum swallowing could be reproduced safely in healthy participants with instruction. Therefore, instructing exhalation before and after vacuum swallowing is recommended to prevent aspiration.

Effects of high-flow nasal therapy on swallowing function: a scoping review.

High-flow nasal therapy is widely used in patients with respiratory failure in different clinical settings, but the effect of high-flow nasal therapy on respiratory-swallow coordination is unknown. Understanding this relationship is crucial, considering the necessity for patients to maintain adequate nutrition during daytime high-flow nasal therapy. This scoping review aims to synthesise available data on the effects of high-flow nasal therapy flow rates on swallowing function and the possible risk of aspiration during treatment, focusing on knowledge and evidence gaps. PubMed, Scopus, Web of Science and Google Scholar databases were searched from inception to 30 May 2023 for studies reporting data on swallowing assessment in healthy adults or patients with acute or chronic respiratory failure receiving high-flow nasal therapy. Data on study design, patients' characteristics and quality outcomes were extracted. Eight studies were included, four including cohorts of healthy volunteers (n=148) and four including patients with acute or chronic respiratory failure (n=151). Study designs, patient populations and quality outcome measures were heterogeneous. Two studies indicated improvement while four articles showed impairment in swallowing function during high-flow nasal therapy; two studies showed that patients' overall clinical picture and underlying medical conditions influenced swallowing-breathing coordination rather than high-flow nasal therapy per se. This scoping review found limited and controversial evidence on the impact of high-flow nasal therapy on swallowing function. Remarkably, methods for swallowing function assessment were quite heterogeneous. Additional research is required to test the effect of high-flow nasal therapy on respiratory-swallowing coordination.

파킨슨병 환자들의 행동학적 기침재활: 주제범위 문헌고찰

Airway protective behaviors including both swallowing and cough are highly interrelated and share sensorimotor control. However, the majority of airway protective rehabilitation has predominantly focused on swallowing function. The aim of this scoping review was to explore the latest evidence on the effects of cough rehabilitation in patients with Parkinson's disease (PD) in order to improve clinical decision-making. A comprehensive search was conducted for articles published in English from January 2013 to March 2023 in PubMed, Embase, and Web of Science. The search was performed using the terms ‘Parkinson's disease’ combined with ‘cough rehabilitation.’ Initial selection was followed by a review of titles, abstracts and/or full texts to exclude irrelevant literature. The final selection included only those articles that focused on behavioral interventions for cough rehabilitation carried out by speech-language pathologists. Among the eight selected articles, four current therapeutic approaches for cough rehabilitation were identified: respiratory muscle strength training (5 studies), Lee Silverman Voice Treatment (LSVT LOUD®) (1 study), respiratory-swallow coordination training (1 study), and sensorimotor training for airway protection (1 study). The review revealed that existing behavioral interventions for cough rehabilitation in PD were effective. Notably, there is an increasing focus on enhancing overall upper airway functions and augmenting sensory perception as well as strengthening muscles for airway protection through cough rehabilitation. Future research would be crucial to facilitate conclusive decision-making for airway protection in clinical environments.

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

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. 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. 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. 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. 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.

(1093) Respiratory-Swallow Coordination in Patients Referred for Lung Transplant Evaluation

(1093) Respiratory-Swallow Coordination in Patients Referred for Lung Transplant Evaluation

Characterizing Swallowing Impairment in a Post-Lung Transplant Population.

Lung transplant recipients carry significant pre- and post-lung transplant dysphagia risk factors related to altered respiratory-swallow coordination as well as acute injury and decompensation resulting in the acute post-lung transplant recovery period. However, we are only beginning to understand the potential physiological contributors to altered swallowing in this population. A retrospective, cross-sectional, cohort study of post-lung transplant patients was performed. All participants received a modified barium swallow study (MBSS) as part of standard care during their acute hospitalization using the Modified Barium Swallow Impairment Profile (MBSImP) protocol and scoring metric. A combination of MBSImP scores, Penetration-Aspiration Scale (PAS) scores, Functional Oral Intake Scale (FOIS) scores, International Dysphagia Diet Standardization Initiative (IDDSI) scale levels, and the time from lung transplant to MBSS was collected, as well as measures of swallowing impairment and swallowing-related outcomes. Differences in swallowing physiology and swallowing-related outcomes between participants with typical versus atypical PAS were explored. Forty-two participants met our prespecified inclusion criteria. We identified atypical laryngeal penetration and/or aspiration in 52.4% of our post-lung transplant cohort. Silent aspiration occurred in 75% of those patients who aspirated. Comparing typical versus atypical PAS scores, we found statistically significant associations with laryngeal elevation (Component 8), p < .0001; anterior hyoid excursion (Component 9), p = .0046; epiglottic movement (Component 10), p = .0031; laryngeal vestibule closure (Component 11), p < .0001; pharyngeal stripping (Component 12), p = .0058; pharyngeal total scores, p = .0001; FOIS scores, p = .00264; and IDDSI liquid levels, p = .0009. Swallowing impairment resulting in abnormal bolus invasion is prevalent in post-lung transplant patients. Airway invasion in this cohort was related to pharyngeal swallow impairment and resulted in modified oral intake. Our findings help expand upon prior literature, which only reported the incidence of aspiration and pathological laryngeal penetration. Our results suggest that the potential for aerodigestive system impairment and negative sequela should not be underestimated in the post-lung transplant population.

Multi-Sensor Respiratory-Swallow Telecare System for Safe Feeding in Different Trunk Inclinations: System Development and Clinical Application.

Proper positioning is especially important to ensure feeding and eating safely. With many nursing facilities restricting visitations and close contact during the coronavirus pandemic, there is an urgent need for remote respiratory-swallow monitoring. This study aimed to develop a semiautomatic feeding telecare system that provides instant feedback and warnings on-site and remotely. It also aimed to analyze the effects of trunk positions on respiratory-swallow coordination. A signal collector with multiple integrated sensors for real-time respiratory-swallow monitoring and warning was developed. A repeated measures design was implemented to evaluate the effects of trunk inclination angles on the swallow-related functions. Significant differences in inclination angles were discovered for swallowing apnea (p = 0.045) and total excursion time of thyroid cartilage (p = 0.037), and pairwise comparisons indicated that these differences were mostly present at 5° to 45°. Alerts were triggered successfully when undesired respiratory patterns or piecemeal occurred. The results indicated that a care recipient can swallow more easily when sitting upright (5°) than when leaning backward (45°). This telecare system provides on-site and remote respiratory-swallow monitoring and alerting for residents in care facilities and can serve as a pipeline for the early screening of swallowing dysfunction.

Cross-System Integration of Respiration and Deglutition: Function, Treatment, and Future Directions.

Swallowing occurs preferentially in the expiratory phase of the quiet breathing cycle and at mid-to-low tidal volume. This coordinative pattern imparts important biomechanical advantages to swallowing and airway protection and facilitate laryngeal elevation, laryngeal vestibular and vocal fold closure, and cricopharyngeal sphincter opening. This preferred coordinative relationship between breathing and swallowing is impaired in a variety of patient populations, including head and neck cancer survivors with dysphagia. We developed a training protocol to re-establish more optimal phasing of swallowing with breathing in these patients with striking outcomes, including reduced swallowing physiological impairments and improved airway protection. This motivated us to continue to refine and expand this training protocol and develop new assistive technologies for swallowing monitoring outside of the lab. In this review, we highlight the origins of our optimal respiratory-swallowing coordination hypothesis, describe the biomechanical advantages it provides, carefully describe our training protocol and findings, and chart a course for the next phase of this work. Our overall goal is to harness technology combined with carefully constructed learning paradigms to improve the lives of patients with impaired respiratory-swallowing coordination consequent to a variety of pathologies including head and neck cancer and degenerative neurological conditions such as Parkinson's disease.

Pilot Study of Respiratory-Swallow Coordination in Amyotrophic Lateral Sclerosis.

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. 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. 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. 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.

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

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). 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. 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). 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.

Advanced Machine Learning Tools to Monitor Biomarkers of Dysphagia: A Wearable Sensor Proof-of-Concept Study

Introduction: Difficulty swallowing (dysphagia) occurs frequently in patients with neurological disorders and can lead to aspiration, choking, and malnutrition. Dysphagia is typically diagnosed using costly, invasive imaging procedures or subjective, qualitative bedside examinations. Wearable sensors are a promising alternative to noninvasively and objectively measure physiological signals relevant to swallowing. An ongoing challenge with this approach is consolidating these complex signals into sensitive, clinically meaningful metrics of swallowing performance. To address this gap, we propose 2 novel, digital monitoring tools to evaluate swallows using wearable sensor data and machine learning. Methods: Biometric swallowing and respiration signals from wearable, mechano-acoustic sensors were compared between patients with poststroke dysphagia and nondysphagic controls while swallowing foods and liquids of different consistencies, in accordance with the Mann Assessment of Swallowing Ability (MASA). Two machine learning approaches were developed to (1) classify the severity of impairment for each swallow, with model confidence ratings for transparent clinical decision support, and (2) compute a similarity measure of each swallow to nondysphagic performance. Task-specific models were trained using swallow kinematics and respiratory features from 505 swallows (321 from patients and 184 from controls). Results: These models provide sensitive metrics to gauge impairment on a per-swallow basis. Both approaches demonstrate intrasubject swallow variability and patient-specific changes which were not captured by the MASA alone. Sensor measures encoding respiratory-swallow coordination were important features relating to dysphagia presence and severity. Puree swallows exhibited greater differences from controls than saliva swallows or liquid sips (p < 0.037). Discussion: Developing interpretable tools is critical to optimize the clinical utility of novel, sensor-based measurement techniques. The proof-of-concept models proposed here provide concrete, communicable evidence to track dysphagia recovery over time. With refined training schemes and real-world validation, these tools can be deployed to automatically measure and monitor swallowing in the clinic and community for patients across the impairment spectrum.

Respiratory-swallow coordination in a rat model of chemoradiation.

Chemoradiation treatment (CRT) for head and neck cancer (HNC) is associated with postswallow inhale events that elevate the risk of penetration/aspiration. The purpose of this study was to assess the validity of a rat model for investigating the effect of CRT on respiratory-swallow coordination. Videofluoroscopic swallow study was performed on 10 Sprague-Dawley rats 3months post-CRT (3mg/kg Cisplatin, 10 fractions of 4.5Gy/day radiotherapy to tongue base), and 10 naïve controls. We examined the effect of CRT on swallow apnea duration, diaphragm movement, and bolus kinematics. CRT rats had a significant increase in postswallow inhale (p=0.008), which was associated with significantly longer swallow apnea durations, lower diaphragm displacement at swallow onset, and faster pharyngoesophageal bolus speed. The rat CRT model is valid for the study of respiratory-swallow coordination due to the consistency of findings in this study with those reported in clinical CRT studies in HNC.

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

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

The Safety, Tolerability, and Impact of Respiratory–Swallow Coordination Training and Expiratory Muscle Strength Training on Pulmonary, Cough, and Swallow Function Surrogates in Amyotrophic Lateral Sclerosis

Purpose This feasibility study examined the safety, tolerability, and impact of expiratory muscle strength training (EMST) combined with respiratory–swallow coordination training (RST) in comparison to EMST alone, and no treatment on pulmonary function, cough function, surrogates of swallow function, and diaphragm thickness in a pre–post small case series of people with amyotrophic lateral sclerosis (ALS). Method This prospective, nonrandomized, delayed intervention case series consisted of six people with ALS: three patients assigned to EMST + RST, two patients assigned to EMST only, and one patient who received no intervention. Patients undergoing treatment underwent a 5-week no-treatment lead-in period before undergoing their respective 5 weeks of treatment with an optional maintenance period for an additional 5 weeks ( n = 4). Primary outcome measures included pulmonary function measurements, scores on the Eating Assessment Tool-10 and Swallowing Related Quality of Life, and diaphragm thickness. Results Descriptive statistics were used to describe outcome measures and individual patient performance. Results revealed that EMST + RST was a safe and well-tolerated intervention, and that both respiratory interventions led to maintenance and improvement of some outcome measures in most patients within this small case series. Conclusion This exploratory study provides preliminary support regarding the tolerability and efficacy of a combined respiratory intervention in a small case series of people with ALS.

The Safety, Tolerability, and Impact of a Combined Respiratory Intervention in Patients With Amyotrophic Lateral Sclerosis (ALS)

To investigate the safety, tolerability, and impact of expiratory muscle strength training (EMST) combined with respiratory-swallow coordination training (RST) to EMST alone, and no treatment, on pulmonary/cough function, swallow function, and diaphragm thickness in a pre-post case series of patients with amyotrophic lateral sclerosis (PALS).

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

PurposeRespiratory–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.MethodThirty 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.ResultsAn 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.ConclusionsIn 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.

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.