A framework for understanding shared substrates of airway protection

Acoustic Features of Airway Protective Maneuvers as Biomarkers of Radiation-Associated Dysphagia and Penetration/Aspiration in Head and Neck Cancer Patients

BACKGROUND

This study aimed at identifying acoustic features of airway protective maneuvers as biomarkers of radiation-associated dysphagia, involving penetration/aspiration and pharyngeal residue.

METHODS

Temporal and spectral acoustical analyses were carried out on voluntary coughs, voluntary throat clearings, and reflexive coughs. Head and neck cancer patients with and without penetration/aspiration were compared. The same was done for patients and healthy controls.

RESULTS

A decreased convexity of the amplitude contour and decreased salience of periodicity in the frequency band 0-400 Hz were observed in induced reflexive coughs of patients compared to healthy controls. A longer length and a less steep slope of the amplitude contour of voluntary throat clearings were observed in patients with penetration/aspiration versus those without.

CONCLUSIONS

Acoustic features of induced reflexive cough discriminate between patients and healthy controls, but do not relate to penetration/aspiration. However, acoustic features of voluntary throat clearing are associated with penetration/aspiration in head and neck cancer patients.

Distinct sensorimotor cough features in a cohort of Progressive Supranuclear Palsy

Background

Progressive Supranuclear Palsy (PSP) and Parkinson's disease (PD) similarly affect many neural substrates; however, some brain regions may be more impacted by PSP vs PD, giving rise to distinct cough features that could facilitate earlier differential diagnosis and inform airway protection therapies to prevent fatal lung infections, since patients may not effectively sense and clear irritants from their airways.

Methods

Thirteen individuals with PSP participated and were age- and sex-matched to persons with PD and healthy, unaffected adults. Using a cross-sectional study design this study aimed to 1) compare cough function in PSP using voluntary and induced reflex cough testing, and 2) compare cough airflow and sensation metrics to PD and healthy adult groups.

Results

Voluntary cough function, particularly cough effectiveness during the expiratory phase, was most impaired in the PSP group (P = 0.047), while expiratory phase timing outcomes only differed between PSP and healthy controls (P = 0.03) during reflex cough. There were no significant differences between groups regarding cough sensation to a cough-inducing stimulus (capsaicin), yet there were more cough responders in PSP vs. PD group.

Conclusions

Degeneration of distinct neural substrates in PSP versus PD may give rise to differentiating sensorimotor cough deficits. Future directions should focus on cough interventions that maintain respiratory health.

Effects of LSVT LOUD and EMST in individuals with Parkinson's disease: A two arm non-randomized clinical trial

PURPOSE

This study compared the effects of Lee Silverman Voice Treatment and Expiratory Muscle Strength Training on swallow, cough, and voice function in individuals with Parkinson's disease.

METHOD

Fifty-eight individuals with mild-moderate Parkinson's disease (male = 45, M = 69 years, SD = 8) were enrolled in a two-treatment clinical trial and completed four consecutive weeks of either Lee Silverman Voice Therapy or Expiratory Muscle Strength Training. All participants completed standard protocol videofluoroscopic swallow study, spirometry-cough tests, acoustic-voice assessment, and self-rated questionnaires pre- and post-therapy. Data were analysed by masked clinicians using specialised software. Mixed-model repeated measures and t-tests were performed.

RESULT

Lee Silverman Voice Treatment resulted in greater effects in acoustic aerodynamic voice measures (loudness, pitch-range, and aerodynamic-efficiency; p < .05) compared to the Expiratory Muscle Strength Training group. There were significant effects on pharyngoesophageal segment maximum opening (p =.01) following Lee Silverman Voice Treatment. Expiratory Muscle Strength Training resulted in significantly greater change in maximum hyoid displacement (Hmax; p = .04) and decreased Hmax duration (p < .01) compared to Lee Silverman Voice Therapy group. No cough measures and self-reported questionnaires significantly differed between groups with both groups improving post-treatment.

CONCLUSION

Both Lee Silverman Voice Therapy and Expiratory Muscle Strength Training improved specific swallow efficiency and airway defence capacity despite differences in task and therapeutic dose. Only Lee Silverman Voice Thearpy improved vocal intensity. Both treatments are feasible options for individuals with mild-moderate Parkinson's disease.

Predictive value of cough peak flow for successful extubation in mechanically ventilated patients after craniotomy: a single-centre prospective diagnostic study

OBJECTIVES

The purpose of this study was to evaluate the predictive value of the cough peak flow (CPF) for successful extubation in postcraniotomy critically ill patients.

DESIGN

This was a single-centre prospective diagnostic study.

SETTING

The study was conducted in three intensive care units (ICUs) of a teaching hospital.

PARTICIPANTS

Postcraniotomy patients who were 18 years or older, stayed in ICU for more than 24 hours and underwent mechanical ventilation for more than 24 hours were eligible for the study. Patients were excluded if one of the following was present: no extubation attempt during the ICU stay; underwent tracheostomy without extubation attempt; pregnant or lactating women; enrolled in other clinical trials; declined to participate in the study. A total of 4879 patients were screened and 1037 were eligible for the study, among whom 785 were included in the study.

OUTCOME MEASURES

CPF, including involuntary (CPF-invol) and voluntary CPF (CPF-vol), were measured before extubation. The area under the receiver operating characteristic curve (AUC) was calculated to explore the diagnostic accuracy of CPF in predicting successful extubation.

RESULTS

There were 641 successful extubation cases (81.7%). The AUC of CPF-invol for predicting successful extubation was 0.810 (95% CI 0.766 to 0.854), with a cut-off value of 63.2 L/min, a sensitivity of 87.4% and a specificity of 66.7%. For conscious patients, the AUC of CPF-invol for the prediction of successful extubation was 0.849 (95% CI 0.794 to 0.904), with a cut-off value of 63.2 L/min and the AUC of CPF-vol was 0.756 (95% CI 0.696 to 0.817), with a cut-off value of 68.2 L/min.

CONCLUSIONS

The CPF was much higher in patients with successful extubation than that in patients with failed extubation. CPF might be valuable for the prediction of extubation outcomes in postcraniotomy critically ill patients. Multicentre studies could be carried out to further validate the results of this study.

TRIAL REGISTRATION NUMBER

NCT04000997.

A Scoping Review on the Intersection Between Voice and Swallowing Measures in Healthy and Disordered Populations

PURPOSE

Voice and swallowing are distinct functions that share anatomical and physiological properties; however, research investigating their intersection is limited. The purpose of this scoping review was to explore the literature surrounding the relationship between voice and swallowing measures in healthy adults and those with non-degenerative disorders. Specifically, we aimed to elucidate whether objective voice measures could be used as correlates of swallowing function.

METHOD

We systematically searched four databases (Embase, PubMed, CINAHL, and Web of Science) for relevant literature using a combination of key words and controlled vocabulary generated from the Yale Mesh Analyzer. The inclusion criteria consisted of peer-reviewed studies in the English language that reported on healthy adults and/or patients with non-degenerative neurological disorders and pulmonary diseases and contained instrumental and/or objective voice and swallowing measures. Two raters completed the abstract screening process followed by independent full-text reviews. Case studies, review studies, gray literature, or abstract-only studies were excluded.

RESULTS

Among 5,485 screened studies, 182 were fully reviewed, with only 11 studies meeting the inclusion criteria. Eight studies found an association between voice and swallowing objective measures, whereas the other three did not. Significant voice measures that were related to swallowing safety and/or physiology included maximum fundamental frequency (F0), F0 range, maximum phonation time, biomechanics of effortful pitch glides, and voice onset time.

CONCLUSIONS

Although there was heterogeneity in the measures used, specific objective voice measures showed promise in clinical practice as a screening tool for dysphagia. Further investigations are needed to validate the clinical utility of these measures across diverse patient populations.

Baroreflex Sensitivity in Patients With Laryngopharyngeal Dysfunction-The Overwhelmed Vagus Hypothesis

Importance

The autonomic nervous system maintains internal stability by concurrently prioritizing and managing different functions. It is currently not known whether dysfunction at the aerodigestive junction could overwhelm autonomic control and impair other functions.

Objective

To compare baroreflex sensitivity, a prognostically significant index of the autonomic system's ability to stabilize blood pressure, between patients with predominantly esophagogastric (digestive) and patients with predominantly laryngopharyngeal (aerodigestive) symptoms.

Design, Setting, and Participants

A cross-sectional study, between 2018 and 2019, of adults undergoing esophagal manometry or transnasal panendoscopy was carried out in a specialist center. The analysis took place between 2023 and 2024.

Main Outcomes and Measures

Heart rate and blood pressure were recorded and baroreflex sensitivity and heart rate variability were derived. Esophageal physiology was assessed with high-resolution manometry.

Results

There were 30 and 23 patients in the digestive and aerodigestive groups, respectively. The mean (SD) age was 61 (15) years and there were 26 women and 27 men. Compared with patients in the digestive group, more patients in the aerodigestive group had voice or throat symptoms and fewer had classic reflux symptoms (odds ratio [OR], 5.65; 95% CI, 1.82-17.5; OR, 2.07; 95% CI, 1.28-3.33; and OR, 0.60; 95% CI, 0.38-0.95, respectively). Patients in the aerodigestive group had higher mean (SD) resting heart rate (93 [17] vs 75 [13] min-1; difference of means, -18 min-1; 95% CI, -26 to -10), lower resting mean (SD) arterial pressure (94 [16] vs 104 [23] mm Hg, OR, 10; 95% CI, -1 to 21), lower mean (SD) baroreflex sensitivity (3.77 [0.79] vs 9.76 [2.92] s-3mm Hg-1; OR, 6.0 s-3mmHg-1; 95% CI, 4.7-7.2), and lower mean (SD) parasympathetic-spectrum heart rate variability (0.68 [0.15] vs 1.30 [0.53]; OR, 0.62; 95% CI, 0.39-0.85). There was a correlation between reduced lower esophageal relaxation (integrated relaxation pressure) and reduced baroreflex sensitivity (r = -0.33; 95% CI, -0.58 to -0.03).

Conclusions

In this cross-sectional study of adults undergoing esophageal manometry or transnasal panendoscopy, patients with laryngopharyngeal symptoms had reduced baroreflex sensitivity, indicating diminished vagal control compared with patients with esophagogastric symptoms. The overwhelmed vagus hypothesis may explain these responses by considering autonomic functions as competing consumers of the finite regulatory resources of a common controller. The regulatory demands of maintaining a safe airway with concurrent laryngopharyngeal sensorimotor dysfunction, superadded to baseline demands for dual speech and aerodigestive control, could overwhelm and force the system to deprioritize less immediate functions like esophageal relaxation and the baroreflex. Measuring baroreflex sensitivity, now possible in routine clinical practice, could enable phenotyping and objective outcome assessment for laryngopharyngeal dysfunction. A neurophysiological model for considering laryngopharyngeal sensorimotor dysfunction could in turn move patient care toward a more holistic autonomic health footing.

Hypotussic cough in persons with dysphagia: biobehavioral interventions and pathways to clinical implementation

Cough is a powerful, protective expulsive behavior that assists in maintaining respiratory health by clearing foreign material, pathogens, and mucus from the airways. Therefore, cough is critical to survival in both health and disease. Importantly, cough protects the airways and lungs from both antegrade (e.g., food, liquid, saliva) and retrograde (e.g., bile, gastric acid) aspirate contents. Aspiration is often the result of impaired swallowing (dysphagia), which allows oral and/or gastric contents to enter the lung, especially in individuals who also have cough dysfunction (dystussia). Cough hyposensitivity, downregulation, or desensitization- collectively referred to as hypotussia- is common in individuals with dysphagia, and increases the likelihood that aspirated material will reach the lung. The consequence of hypotussia with reduced airway clearance can include respiratory tract infection, chronic inflammation, and long-term damage to the lung parenchyma. Despite the clear implications for health, the problem of managing hypotussia in individuals with dysphagia is frequently overlooked. Here, we provide an overview of the current interventions and treatment approaches for hypotussic cough. We synthesize the available literature to summarize research findings that advance our understanding of these interventions, as well as current gaps in knowledge. Further, we highlight pragmatic resources to increase awareness of hypotussic cough interventions and provide support for the clinical implementation of evidence-based treatments. In culmination, we discuss potential innovations and future directions for hypotussic cough research.

Post-Radiotherapy Dysphagia in Head and Neck Cancer: Current Management by Speech-Language Pathologists

OPINION STATEMENT

Dysphagia, difficulty in eating and drinking, remains the most common side effect of radiotherapy treatment for head and neck cancer (HNC) with devastating consequences for function and quality of life (QOL). Over the past decade, 5-year survival has improved due to multiple factors including treatment advances, reduction in smoking, introduction of the human papillomavirus (HPV) vaccine and more favourable prognosis of HPV-related cancers. Increased prevalence of HPV-positive disease, which tends to affect younger individuals, has led to an elevated number of people living for longer with the sequelae of cancer and its treatment. Symptoms are compounded by late effects of radiotherapy which may lead to worsening of dysphagia for some long-term survivors or new-onset dysphagia for others. Speech-language pathology (SLP) input remains core to the assessment and management of dysphagia following HNC treatment. In this article, we present current SLP management of dysphagia post-radiotherapy. We discuss conventional treatment approaches, the emergence of therapy adjuncts and current service delivery models. The impact of adherence on therapy outcomes is highlighted. Despite treatment advancements, patients continue to present with dysphagia which is resistant to existing intervention approaches. There is wide variation in treatment programmes, with a paucity of evidence to support optimal type, timing and intensity of treatment. We discuss the need for further research, including exploration of the impact of radiotherapy on the central nervous system (CNS), the link between sarcopenia and radiotherapy-induced dysphagia and the benefits of visual biofeedback in rehabilitation.

Cough and Swallowing Therapy and Their Effects on Vocal Fold Bowing and Laryngeal Lesions

OBJECTIVE

Expiratory muscle strength training (EMST) and sensorimotor training of airway protection (smTAP) are two exercises intended to improve cough and swallowing in people with Parkinson's Disease (PwPD). The aims of this study were to (1) examine whether EMST or smTAP elicit changes to vocal fold bowing; and (2) describe the safety of EMST and smTAP as it relates to the development of vocal fold lesions.

METHOD(S)

This was a secondary analysis of data from PwPD who completed EMST or smTAP as part of a prospective randomized controlled trial. Vocal fold bowing (BI) and the presence of laryngeal lesions were blindly analyzed from flexible endoscopic evaluation of swallowing (FEES) using ImageJ software and operational definitions. Linear regression was used to examine the influence time (pre- vs. post-therapy) and therapy (EMST vs. smTAP) on vocal fold bowing. Descriptive statistics were used to describe the presence of laryngeal lesions.

RESULT(S)

Overall, 56 participants were included, 28 per group. The median BI scores pre- and post-therapy were 8.2% and 8.3% for the EMST group and 11.3% and 8.4% for the smTAP group, respectively. Statistical analyses revealed insufficient evidence to suggest an effect of time and treatment type on BI (p > 0.05) or on the presence of vocal fold lesions (p > 0.05).

CONCLUSION

Based on these and previous findings, it appears that changes in vocal fold bowing do not drive treatment effects following EMST and smTAP. Also, this study further supports the safety of smTAP and EMST despite the required forceful exhalation and repetitive coughing.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1127-1132, 2024.

Cough Correlates of Functional Swallow Outcomes in Atypical Parkinsonism

BACKGROUND

Swallow and cough impairments lead to aspiration and reduced clearance of aspirate material. Both behaviors are impaired in Parkinson's disease, but it is unknown whether a similar relationship of dysfunction exists in forms of atypical Parkinsonism (APD). Elucidating this association in APD may lead to early, comprehensive airway protection treatment.

OBJECTIVES

We tested the hypotheses that swallow deficits in APD are associated with impaired cough and that airway protective dysfunction is associated with longer disease duration.

METHODS

Swallowing difficulty was described by 11 participants with APD. Penetration-Aspiration Scale (PAS) and DIGEST scores for thin liquid trials were extracted from medical records of videofluoroscopic swallow study reports. Voluntary and capsaicin induced-reflex cough measures of flow, volume, and timing were analyzed.

RESULTS

While most participants did not have post-swallow residue, ~80% received abnormal PAS scores and reported swallowing difficulty. Those with abnormal PAS scores had lower voluntary cough expired volume (P = 0.037; mean rank difference = 5.0); lower reflex inspiratory flow rate (P = 0.034; mean rank difference = 5.5); and longer reflex expiratory flow rise time (P = 0.034; mean rank difference = 5.5). Higher PAS scores and reduced reflex cough volume acceleration were significantly correlated (r = -0.63; P = 0.04) and longer disease duration predicted larger voluntary cough expired volume (R2  = 0.72) and longer flow rise times (R2  = 0.47).

CONCLUSIONS

As swallow safety worsens, so might the ability to clear the airways with effective cough in in APD; particularly with longer disease duration. Assessing cough in conjunction with swallowing is important for informing airway protection treatment plans in APD.

Accumulated Secretions and Associated Aerodigestive Function in Patients With Dysphagia

PURPOSE

Accumulated pharyngo-laryngeal secretions are associated with dysphagia, aspiration, and poor health outcomes. Despite ongoing developments in the evaluation of pharyngo-laryngeal secretions, understanding of the underlying mechanisms is limited. Pathophysiology associated with accumulated secretions is needed to guide tailored, targeted treatment pathways. This study reports the prevalence of accumulated pharyngo-laryngeal secretions in a large acute care caseload and explores the relationship between secretions and aerodigestive function.

METHOD

Consecutive inpatients (N = 222) referred for flexible endoscopic evaluation of swallow (FEES) with suspected dysphagia following assessment by a speech-language pathologist were recruited (43% neurological, 22% neurosurgical, 20% critical care, 15% other), and 250 standardized FEES were completed (222 first FEES, 28 repeat FEES). The assessment protocol included secretion assessment using the New Zealand Secretion Scale (NZSS), pharyngeal squeeze maneuver, laryngeal motor and sensory assessment, Penetration-Aspiration Scale, and Yale Pharyngeal Residue Severity Rating Scale. Urge-to-clear ratings were collected during endoscopy. Cough peak expiratory flow and swallow frequency measures were also collected, as well as clinical outcomes at time of discharge.

RESULTS

There was a high incidence of accumulated secretions, with 77% of inpatients having elevated NZSS (Mdn = 3, range: 0-7) and 37% with pooled laryngeal secretions. Accumulated secretions were associated with reduced swallow frequency, reduced laryngeal adductor reflex, impaired pharyngeal squeeze maneuver, and peak expiratory flow. NZSS scores also correlated with swallow measures (Penetration-Aspiration Scale and Yale Pharyngeal Residue Severity Rating Scale) and patient outcomes including diet recommendations at discharge and pneumonia during admission.

CONCLUSIONS

This large study contributes to evidence associating both sensory and motor impairments with secretion accumulation and aspiration risk. Further exploration of the key physiological mechanisms contributing to accumulated secretions will serve as markers to provide proof of principle for targets for secretion management protocols.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24101667.

Motor Performance During Sensorimotor Training for Airway Protection in Parkinson's Disease

INTRODUCTION

Cough dysfunction is highly prevalent in Parkinson's disease (PD) and associated with pneumonia, a leading cause of death. Although research suggests that cough can be volitionally upregulated, patterns of improvements that occur during cough skill training and potential correlates remain unexamined. Therefore, we sought to characterize changes to peak flow during cough skill training, examine whether early variability predicted motor performance trajectories during treatment, and explore the relationship between peak flow during cough skill training and motor learning on a similar but untrained task (i.e., reflex cough testing).

METHOD

This secondary analysis of treatment data from a randomized controlled trial included 28 individuals with PD who participated in five sessions of sensorimotor training for airway protection (smTAP). During this novel cough skill training, participants completed 25 repetitions of coughs targeting peak flow 25% above their baseline. Reflex and voluntary cough testing was performed pre- and posttreatment. Bayesian multilevel growth curve models provided group and individual-level estimates of peak flow during training.

RESULTS

The magnitude and consistency of peak flow increased during cough skill training. Variability in peak flow during the first treatment session was associated with greater improvements to peak flow in later sessions. There was no relationship between changes to peak flow during cough skill training and motor learning.

CONCLUSIONS

Individuals with PD improved the strength and variability of cough peak flow during cough skill training. These findings provide a clinically relevant characterization of motor performance during cough skill training and lend insight into potential correlates to guide future treatment paradigms.

Cut-Off Value of Voluntary Peak Cough Flow in Patients with Parkinson's Disease and Its Association with Severe Dysphagia: A Retrospective Pilot Study

Background and Objectives. Swallowing and coughing reflexes are both closely associated with airway protection. Peak cough flow (PCF) is associated with dysphagia in several neurogenic diseases. In this study, we aimed to analyze the relationship between PCF and aspiration in Parkinson's disease (PD) and determine the cut-off value of PCF. Materials and Methods. We retrospectively analyzed the records of patients with PD who underwent a videofluoroscopic swallowing study and checked for PCF. A total of 219 patients were divided into an aspiration group (n = 125) and a non-aspiration group (n = 94). Results. Significantly lower PCF values were observed in the aspiration group compared to the non-aspiration group (132.63 ± 83.62 vs. 181.38 ± 103.92 L/min, p < 0.001). Receiver operating characteristic curve analysis revealed that a PCF cut-off value of 153 L/min (area under the receiver operating characteristic curve, 0.648; sensitivity, 73.06%; specificity, 51.06%) was associated with aspiration in PD. Additionally, a univariate analysis showed that the male sex, lower body mass indexes, higher Hoehn and Yahr scales, and PCF values of ≤153 L/min indicated an increased risk of aspiration. Conclusions. Through a multivariate analysis, we demonstrated that a PCF value ≤153 L/min was associated with an increased risk of aspiration (odds ratio 3.648; 1.797-7.407), highlighting that a low PCF is a risk factor for aspiration in patients with PD.

Primary site of constriction during the compression phase of cough in healthy young adults

Glottal closure has been considered as the primary constriction point during the compression phase (CP); however, vocal fold adduction alone cannot resist the high pressures, providing motivation to explore other mechanisms contributing to that resistance. The goal of this study was to identify site(s) and degree of constriction during the CP of cough of varying types in healthy young adults. Twenty-five healthy young participants participated in this study. The experimental protocol was comprised of: 1) baseline pulmonary function measures; 2) cough practice to establish weak, moderate and strong coughs; 3) voluntary and reflex cough assessments with fluoroscopy and airflow measures. We used a repeated measures ANOVA to identify whether there are differences in constriction ratio between cough types. There was a significant difference in constriction of varying cough types. Degree of constriction in all cough strengths showed that the glottis was the most constricted area, followed by the laryngeal vestibule, nasopharynx, hypopharynx, oropharynx, and cervical trachea, in order, but stronger cough resulted in more constriction in all areas compared to weaker cough. Degree of constriction in reflex cough showed a similar pattern though there was greater constriction in the oropharynx than the hypopharynx. Airflow measures in voluntary cough were consistent with previous findings. Differences in upper airway constriction during the compression phase of cough may be attributed to differences in motor control between reflex and voluntary cough, and the increased constriction seen during strong cough may reflect increased muscle recruitment during that task. In the future, we can use this knowledge to develop novel methods for cough rehabilitation.

Assessing the effect of transcranial magnetic stimulation on peak cough flow in patients with supratentorial cerebral infarction: A retrospective cohort study

Respiratory dysfunction following supratentorial cerebral infarction leads to pneumonia and is a major cause of mortality. Decreased voluntary cough function impairs the ability to clear mucus or secretions from the airways and increases the risk of aspiration pneumonia. Peak cough flow (PCF) is one of the objective tools for evaluating voluntary cough function. Repetitive transcranial magnetic stimulation (rTMS) could be applied to the respiratory motor cortex to improve respiratory function. Little is known about the effect of rTMS on PCF in patients with supratentorial cerebral infarction during the subacute period. This study aimed to determine whether rTMS treatment could improve PCF in patients with supratentorial cerebral infarction. We retrospectively recruited patients with subacute supratentorial cerebral infarction who underwent a PCF test. The rTMS group received a combination of rTMS treatment for 2 weeks and conventional rehabilitation for 4 weeks. However, the control group underwent only conventional rehabilitation for 4 weeks. PCF tests were performed before and after treatment and the results were compared between the 2 groups. In total, 145 patients with supratentorial cerebral infarctions were recruited. The PCF parameters before and after treatment increased in both the rTMS and control groups. However, the rTMS group showed a greater increase in PCF values compared with the control group. In patients with supratentorial cerebral infarction, the combination of conventional rehabilitation and rTMS in the subacute period may be helpful in improving voluntary cough function compared with conventional rehabilitation alone.

Swallowing outcomes in dysphagia interventions in Parkinson's disease: a scoping review

OBJECTIVES

To identify all outcomes, their definitions, outcome measurement instruments (OMIs), timepoints and frequency of measurement applied in clinical trials in oropharyngeal dysphagia (OD) interventions in Parkinson's disease (PD). This scoping review is the first stage of a larger project establishing a core outcome set for dysphagia interventions in Parkinson's disease (COS-DIP).

DESIGN

Scoping review.

METHODS

Six electronic databases and one trial registry were searched without language restrictions until March 2022. Bibliography lists of included studies were also reviewed. Study screening and data extraction were conducted independently by two reviewers using Covidence. The scoping review protocol is registered and published (http://hdl.handle.net/2262/97652).

RESULTS

19 studies with 134 outcomes were included. Trial outcomes were mapped to a recommended taxonomy for COSs and merged. 39 outcomes were identified. The most frequently measured were general swallowing-related outcomes, global quality-of-life outcomes and swallowing-related perceived health status outcomes. The applied outcomes, their definitions, OMIs, timepoints and frequency of measurement showed a high variability across all studies.

CONCLUSIONS

The high variability of outcomes emphasises the need for an agreed standardised COS. This will inform clinical trial design in OD in PD, increase the quality of OD trials in PD and facilitate synthesising and comparing study results to reach conclusion on the safety and effectiveness of OD interventions in PD. It will not prevent or restrict researchers from examining other outcomes.

TRIAL REGISTRATION NUMBER

The COS-DIP study, including the scoping review, was registered prospectively with the Core Outcome Measures in Effectiveness Trials Database on 24 September 2021 (www.comet-initiative.org, registration number: 1942).

Changes in Cough Airflow and Acoustics After Injection Laryngoplasty

OBJECTIVE/HYPOTHESIS

We explored the following hypotheses in a cohort of patients undergoing injection laryngoplasty: (1) glottic insufficiency affects voluntary cough airflow dynamics and restoring glottic competence may improve parameters of cough strength, (2) cough strength can be inferred from cough acoustic signal, and (3) glottic competence changes cough sounds and correlates with spectrogram morphology.

STUDY TYPE/DESIGN

Prospective interventional study.

METHODS

Subjects with glottic insufficiency secondary to unilateral vocal fold paresis, paralysis, or atrophy, and scheduled for injection laryngoplasty completed an instrumental assessment of voluntary cough airflow using a pneumotachometer and a protocolized voluntary cough sound recording. A Wilcoxon signed-rank test was used to compare the differences between pre- and post-injection laryngoplasty in airflow and acoustic measures. A Spearman rank-order correlation was used to evaluate the association between airflow and acoustic cough measures.

RESULTS

Twenty-five patients (13F:12M, mean age 68.8) completed voluntary cough airflow measurements and 22 completed cough sound recordings. Following injection laryngoplasty, patients had a statistically significant decreased peak expiratory flow rise time (PEFRT) (mean change: -0.03 s, SD: 0.06, p = 0.04) and increased cough volume acceleration (mean change: 13.1 L/s2 , SD: 33.9, p = 0.03), suggesting improved cough effectiveness. Correlation of cough acoustic measures with airflow measures showed a weak relationship between PEFRT and acoustic energy (coefficient: -0.31, p = 0.04) and peak power density (coefficient: -0.35, p = 0.02).

CONCLUSIONS

Our study thus indicates that injection laryngoplasty may help avert aspiration in patients with glottic insufficiency by improving cough effectiveness and that improved cough airflow measures may be tracked with cough sounds.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:S1-S14, 2023.

A prospective examination of swallow and cough dysfunction after lung transplantation

OBJECTIVES

Swallow and cough dysfunction are possible surgical complications of lung transplantation (LT). We examined voluntary cough strength, sensorimotor reflexive cough integrity, and swallow-related respiratory rate (RR) across swallowing safety and aspiration response groups in recovering LT recipients.

METHODS

Forty-five LT recipients underwent flexible endoscopic evaluation of swallowing indexed by the validated Penetration Aspiration Scale. RR before and after a 3-ounce water drinking task was measured. Voluntary and reflexive cough screening were performed to index motor and sensory outcomes. T-tests, one-way ANOVAs, and chi-square (odds ratios) were used.

RESULTS

60% of patients exhibited laryngeal penetration (n = 27) and 40% demonstrated tracheal aspiration (n = 18); 72% (n = 13) demonstrated silent aspiration. Baseline RR was higher in aspirators versus non-aspirators (26.5 vs. 22.6, p = 0.04) and in silent aspirators compared to non-silent aspirators (27.9 vs. 20.7, p = 0.01). RR change post-swallowing did not differ between aspiration response groups; however, it was significantly higher in aspirators compared to non-aspirators (3 vs. -2, p = 0.02). Compared to non-silent aspirators, silent aspirators demonstrated reduced voluntary cough peak expiratory flow (PEF; 166 vs. 324 L/min, p = 0.01). PEF, motor and urge to cough reflex cough ratings did not differ between aspirators and non-aspirators. Silent aspirators demonstrated a 7.5 times higher odds of failing reflex cough screening compared to non-silent aspirators (p = 0.07).

CONCLUSIONS

During the acute recovery period, all LT participants demonstrated some degree of unsafe swallowing and reduced voluntary cough strength. Silent aspirators exhibited elevated RR, reduced voluntary cough physiologic capacity to defend the airway, and a clinically distinguishable blunted motor response to reflex cough screening.

Effects of behavioural swallowing therapy in patients with Parkinson's disease: A systematic review

PURPOSE

A previous 2014 systematic review outlining the treatment effects of swallowing therapies in Parkinson's disease (PD) demonstrated a lack of well-designed randomised controlled studies. This current review presents and evaluates the latest evidence for behaviour swallowing therapies for PD-related dysphagia to enhance speech-language pathologists' evidence-based decision-making around treatment choices.

METHOD

A systematic review of articles published in English and Korean was conducted from January 2014 through June 2020 using the electronic databases PubMed, Embase, and Cochrane Library. Two authors independently searched the literature and differences after the search were settled following discussion and consensus. Identified studies were evaluated for quality with the ABC rating scale and critical appraisal criteria.

RESULT

Eight studies after initial search and three additional studies which met our original criteria but were not freely available, or published after the initial search period were also included. Eleven studies included the following treatments: biofeedback therapy (N = 1), respiratory-swallow coordination training (N = 2), neuromuscular electrical stimulation (NMES) (N = 1), expiratory muscle strength training (EMST) (N = 2), intensive exercise-based swallowing program (ISP) (N = 1), chin-down strategy (N = 2), Lee Silverman Voice Treatment (N = 1), and therapeutic singing (N = 1).

CONCLUSION

Most of the behavioural therapies improved swallowing function in PD. Treatments that enhanced airway function globally demonstrated positive effects on swallow function as did intensive, targeted swallowing treatment. However, the chin-down strategy did not show a significant effect on swallowing measured by flexible endoscopic evaluations of swallowing. EMST detraining effects implied a need to design maintenance training in PD. In the future, well-designed randomised controlled trials are needed to consolidate the effects of these therapies.

Examining the Influence of Chemosensation on Laryngeal Health and Disorders

Inhaled airborne stimuli are associated with laryngeal disorders affecting respiration. Clinically, several themes emerged from the literature that point to specific gaps in the understanding and management of these disorders. There is wide variation in the types of airborne stimuli that trigger symptoms, lack of standardization in provocation challenge testing using airborne stimuli, and vague reporting of laryngeal symptoms. Scientifically, evidence exists outside the field of voice science that could prove useful to implement among patients with impaired laryngeal-respiration. To expand this area of expertise, here we provide a thematic overview of relevant evidence and methodological tools from the discipline of chemosensory sciences. This review provides distinctions across the three chemosensory systems of olfaction, trigeminal chemesthesis, and gustation, guidance on selecting and delivering common chemosensory stimuli for clinical testing, and methods of quantifying sensory experiences using principles of human psychophysics. Investigating the science of chemosensation reveals that laryngeal responses to inhaled airborne stimuli have explanations involving physiological mechanisms as well as higher cognitive processing. Fortunately, these findings are consistent with current pharmacological and nonpharmacological interventions for impaired laryngeal-respiration. Based on the close relationships among inhaled airborne stimuli, respiration, and laryngeal function, we propose that new perspectives from chemosensory sciences offer opportunities to improve patient care and target areas of future research.

Rehabilitating Cough Dysfunction in Parkinson's Disease: A Randomized Controlled Trial

BACKGROUND

Disorders of airway protection (cough and swallowing) are pervasive in Parkinson's disease (PD) resulting in a high incidence of aspiration pneumonia and death. However, there are no randomized controlled trials comparing strength and skill-based approaches to improve airway protection in PD.

OBJECTIVES

The aim of this study was to compare expiratory muscle strength training (EMST) and sensorimotor training for airway protection (smTAP) to improve cough-related outcomes in people with PD.

METHODS

Participants with PD and dysphagia were recruited for this prospective phase II randomized-blinded controlled clinical trial. Participants completed baseline assessment, 5 weeks of EMST or smTAP, and a post-training assessment. Primary outcome measures included maximum expiratory pressure (MEP) and voluntary cough peak expiratory flow rate (PEFR). Mixed effects models were used to assess the effects of EMST and smTAP on outcomes.

RESULTS

A total of 65 participants received either EMST (n = 34) or smTAP (n = 31). MEP improved from pre- to post-treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.53). Voluntary PEFR increased from pre- to post-treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.06). Moreover, reflex cough PEFR (P < 0.001, d = 0.64), reflex cough expired volume (P < 0.001, d = 0.74), and urge to cough (P = 0.018, OR = 2.70) improved for the smTAP group but not for the EMST group.

CONCLUSIONS

This clinical trial confirmed the efficacy of smTAP to improve reflex and voluntary cough function, above and beyond EMST, the current gold standard. © 2022 International Parkinson and Movement Disorder Society.

Rehabilitation of Airway Protection in Individuals With Movement Disorders: A Telehealth Feasibility Study

PURPOSE

Airway protective deficits (swallowing and cough) greatly reduce health and quality of life and are a pervasive consequence of neurodegenerative movement disorders. Expiratory muscle strength training (EMST) and cough skill training (CST) are two treatment approaches to improve airway protection; however, many patients are unable to access these treatments. Telehealth may improve access to care, but it remains unknown whether these treatments are feasible and efficacious via telehealth. This study aimed to determine the practical feasibility and preliminary treatment effect of EMST and CST via telehealth.

METHOD

Twenty participants with movement disorders completed 4 weeks of EMST and 2 weeks of CST, including two clinician-directed treatment sessions via telehealth and 3 days of home practice per week. Feasibility was calculated for each treatment. Practical feasibility was defined as completing treatment (EMST or CST) and obtaining the relevant outcome measures-a proxy of maximum expiratory pressure (pMEP) for EMST and peak expiratory flow rate (PEFR) for CST-within a 30-min session/period. Session factors that may have influenced feasibility were examined. Preliminary treatment effect was defined as changes in pMEP and PEFR.

RESULTS

Time taken to obtain pMEP and complete EMST was 17.48 min, and time taken to obtain PEFR and complete CST was 17.69 min. pMEP, single voluntary cough PEFR, and sequential voluntary cough PEFR increased from pre- to posttreatment.

CONCLUSIONS

Findings suggest that the delivery of EMST and CST is feasible via telehealth and yield improvements to pMEP and PEFR. This has important implications for expanding service delivery of airway protective interventions and reducing health care disparities in people with neurodegenerative movement disorders.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21357669.

Incidence, clinical signs, and videofluoroscopic swallow study abnormalities associated with airway penetration and aspiration in 100 dogs

BACKGROUND

Videofluoroscopic swallow studies (VFSS) utilizing penetration-aspiration (P-A) scoring assesses airway protection in people. On VFSS, penetration (ingesta or secretions immediately cranial to the vocal folds) and aspiration (material caudal to the vocal folds) are associated with increased risk of lung injury in people. Penetration-aspiration (P-A) scoring has been validated in animal models, but the incidence of P-A, clinical signs (CS), and dysphagic disorders associated with P-A in dogs are unknown.

OBJECTIVES

Using VFSS, identify the incidence of P-A, compare CS between dogs with and without P-A, and identify predisposing dysphagic abnormalities for P-A.

ANIMALS

One hundred client-owned dogs.

METHODS

Sequential VFSS and associated medical records from dogs presenting to the veterinary teaching hospitals at Auburn University (n = 53) and the University of Missouri (n = 47) were retrospectively reviewed. Statistical comparisons were made using Mann-Whitney tests, one-way analysis of variance (ANOVA) on ranks, multiple linear regression, and Spearman rank order correlation (P < .05).

RESULTS

On VFSS, the incidence of pathologic P-A was 39%. No significant differences in CS were found between dogs with or without P-A (P > .05), with 14/39 dogs with P-A presenting without respiratory CS. Pharyngeal (P < .001) and esophageal (P = .009), but not oral-preparatory (P = .2) dysphagia was more common with P-A. Pharyngeal weakness (P < .001) and esophago-oropharyngeal reflux (EOR; P = .05) were independent predictors of P-A and were moderately and weakly positively correlated with P-A score respectively (P < .001, r = 0.489; P = .04, r = 0.201).

CONCLUSIONS

Penetration-aspiration occurs in dogs in the absence of respiratory CS (i.e., occult P-A). Dogs with pharyngeal weakness and EOR should be considered at risk for P-A.

Voluntary Cough Testing as a Clinical Indicator of Airway Protection in Cervical Spinal Cord Injury

OBJECTIVE

Voluntary cough testing (VCT) may be useful for determining aspiration risk in neurogenic dysphagia; however, has yet to be investigated in traumatic cervical spinal cord injury (tCSCI). The study explored if VCT may elucidate swallowing safety and kinematics related to airway protection in tCSCI survivors.

METHODS

Ten inpatients, 13-73 days post-tCSCI (7 incomplete injuries), completed VCT and a modified barium swallowing study that was analyzed via the Penetration Aspiration Scale (PAS) and norm-referenced measures of swallowing events related to airway protection. Spearman rho correlations explored relations among cough airflow, median PAS, and airway protection. Mann-Whitney U tests explored group differences based on clinical airway invasion (PAS > 2) and receiver operating characteristic statistics probed the sensitivity/specificity of VCT measures.

RESULTS

Safe (PAS > 2) and unsafe swallowers differed by cough volume acceleration (CVA) for the total sample and by inspiratory duration for incomplete injuries (p = 0.03, r > 0.7). A cut-off value of 24.8 L/s for CVA predicted airway invasion (AUC = 0.917, p = 0.03) with sensitivity = 100%/specificity = 75%. CVA correlated with delayed laryngeal vestibule closure during swallowing for both the total sample and for incomplete injuries (r_s  > 0.6, p < 0.05). Blunted peak flow and prolonged cough phases were associated with disordered laryngeal kinematics and prolonged bolus transit during swallowing (p < 0.05).

CONCLUSIONS

Reduced CVA, blunted peak flow, and prolonged cough phases reflected PAS and disrupted mechanisms of airway protection in tCSCI survivors, demonstrating promise for VCT as a clinical assessment for post-tCSCI dysphagia.

LEVEL OF EVIDENCE

3 Laryngoscope, 2022.

Pilot Study of Respiratory-Swallow Coordination in Amyotrophic Lateral Sclerosis

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.

A New Therapeutic Approach for Dystussia and Atussia in Neurogenic Dysphagia: Effect of Aerosolized Capsaicin on Peak Cough Flow

Swallowing and cough are crucial components of airway protection. In patients with neurogenic dysphagia (ND), there is a high prevalence of dystussia (impaired cough) and atussia (absence of cough). As a result, the ability to detect and remove aspirated material from the airway decreases, exacerbating the sequelae associated with ND, including aspiration pneumonia, a leading cause of mortality in ND. This controlled intervention study aimed to quantify the cough response to aerosolized capsaicin (AC) in patients with ND and assess the potential of AC as a therapeutic tool in treating ND-related dystussia and atussia. Furthermore, we propose a novel application method that enables AC treatment to be performed at home. Spirometry was used to measure peak cough flow (PCF) of voluntary cough (cough on command) and reflexive cough (cough secondary to pharyngeal exposure to AC) in 30 subjects with and 30 without ND. The capsaicin aerosol was generated by adding 1-10 drops of liquid cayenne extract (1.5-2% capsaicin) to 100 mL carbonated water (0.00075-0.001% to 0.0075-0.01% capsaicin). Voluntary PCF in the ND group was significantly lower than in the control group (p < 0.001), while there was no significant difference in reflexive PCF (p = 0.225). Within the ND group, reflexive PCF was significantly higher than voluntary PCF (p = 0.001), while in healthy controls, reflexive PCF was significantly lower (p < 0.001). The data show that AC increased the tracheobronchial clearance efficacy in ND patients with dystussia and atussia, as it enabled subjects to access their individual cough potential, which is present, but inaccessible, due to neurological disorder.

A Survey of Speech-Language Pathologists' Experience With Clinical Cough Assessment

PURPOSE

The purpose of this study was to determine if students (clinicians-intraining) and clinicians of speech-language pathology assess cough during clinical swallow evaluations. We also sought to determine if participants received background education and training regarding implementation of clinical cough assessment. Finally, we aimed to identify participant interest in a cough assessment training program.

METHOD

A clinician-researcher panel developed a 20-question survey to address specific aims. The final survey was distributed via social media and a clinical dysphagia website after two phases of revision.

RESULTS

A percentage (84.6%) of the survey participants reported that they assess cough in clinical swallow evaluations, mainly using subjective measures. The majority of clinicians reported no background education or skilled training to implement cough assessment. Background education and training was higher for participants outside the United States, although the total sample size of that group was small. Almost all participants (97.8%) were interested in a cough training program.

CONCLUSIONS

Many practicing clinicians in this survey reported that they complete cough assessments, despite limited education and training to do so. However, they also reported high interest in participating in a clinical cough assessment training program, which would support the field of speech-language pathology and patients at risk of airway protective dysfunction.

Assessment of dysarthria and dysphagia in patients with amyotrophic lateral sclerosis: Review of the current evidence

Bulbar dysfunction is a common presentation of amyotrophic lateral sclerosis (ALS) and significantly impacts quality of life of people with ALS (PALS). The current paper reviews measurements of dysarthria and dysphagia specific to ALS to identify efficient and valid assessment measures. Using such assessment measures will lead to improved management of bulbar dysfunction in ALS. Measures reviewed for dysarthria in PALS are organized into three categories: acoustic, kinematic, and strength. A set of criteria are used to evaluate the effectiveness of the measures' identification of speech impairments, measurement of functional verbal communication, and clinical applicability. Assessments reviewed for dysphagia in PALS are organized into six categories: patient reported outcomes, dietary intake, pulmonary function and airway defense capacity, bulbar function, dysphagia/aspiration screens, and instrumental evaluations. Measurements that have good potential for clinical use are highlighted in both topic areas. Additionally, areas of improvement for clinical practice and research are identified and discussed. In general, no single speech measure fulfilled all the criteria, although a few measures were identified as potential diagnostic tools. Similarly, few objective measures that were validated and replicated with large sample sizes were found for diagnosis of dysphagia in PALS. Importantly, clinical applicability was found to be limited; thus, a collaborative team focused on implementation science would be helpful to improve the clinical uptake of assessments. Overall, the review highlights the need for further development of clinically viable and efficient measurements that use a multidisciplinary approach.

Sensorimotor Cough Dysfunction Is Prevalent and Pervasive in Progressive Supranuclear Palsy

BACKGROUND

Pneumonia, a leading cause of death in progressive supranuclear palsy (PSP), results from progressive and pervasive deficits of airway protection, including both cough and swallowing dysfunction. Cough protects the airway by expelling aspirate and may be an important therapeutic target to protect against pneumonia in the presence of dysphagia. However, cough has not been objectively characterized in PSP or compared to other common forms of parkinsonism, such as Parkinson's disease (PD).

OBJECTIVE

The purpose of this study was to examine voluntary and reflex cough function in PSP, as compared to patients with PD matched for disease duration.

METHODS

Twenty-six patients with PSP and 26 with PD completed voluntary and reflex cough testing via spirometry. Linear mixed effects models examined comparisons between groups and within cough types across cough sensory and motor outcomes.

RESULTS

Patients with PSP demonstrated significantly reduced cough motor function compared to PD, specifically reduced peak expiratory flow rate (P < 0.001), cough expiratory volume (P < 0.001), and cough inspiratory volume (P = 0.008). Both groups showed similar reflex cough thresholds (P = 0.694), but PSP demonstrated an increased perception of cough stimuli (P = 0.041).

CONCLUSIONS

These findings suggest that sensorimotor cough dysfunction is prevalent in PSP, and cough motor deficits, in particular, are worse in PSP than in PD. These deficits likely contribute to the pathogenesis of pneumonia in PSP. Therefore, cough should be integrated into assessments of airway protection and considered as a therapeutic target to potentially reduce adverse health events and improve quality of life in this population. © 2021 International Parkinson and Movement Disorder Society.

Objective measurement of acoustic intensity of coughing for clearance of penetration and aspiration on video-fluoroscopy

PURPOSE

This preliminary, exploratory study evaluated the acoustic intensity of effective and ineffective clearance of penetrated and aspirated material from the laryngeal vestibule in patients with dysphagia.

METHOD

A lapel microphone was attached anterior to participants' tragus and recorded coughing in decibels during their videofluoroscopic swallowing studies (VFSS).

RESULT

Eighty-eight patients were recruited. Thirteen patients, with visible airway invasion and coughing were included in the final analysis. No coughs were effective at expelling aspirated material from the airway (n = 10). Both effective (4/7) and ineffective (3/7) coughing to penetration were recorded. The mean acoustic intensity of effective coughing to penetration was -44.0 dBFS (decibel level relative to full scale) [SD = 7.3, 95% CI = -51.14, -36.86], and ineffective coughing to penetration was only marginally lower at -42.9 dBFS [SD = 2.0, 95% CI = -45.21, -40.59].

CONCLUSION

No coughs were effective at expelling aspirated material from the airway. Some coughs effectively expelled penetrated material from the airway. However, the relationship between acoustic intensity and cough effectiveness is unclear due to the limited number of observations. Given that perceptual evaluation of coughing is widely used in dysphagia clinical practice to determine cough effectiveness, this is an important area for future research.

Prevalence and risk factors of choking in older adults with intellectual disability: Results from a national cross-sectional study

BACKGROUND

Choking is a serious and under-recognised condition for adults with intellectual disability (ID), with health, psychological and potentially fatal consequences. This study aims to determine the prevalence and risk factors for choking in a population-based sample of older adults with ID.

METHOD

597 adults with ID (mean age: 60 years old; SD = 8) were selected as part of The Intellectual Disability Supplement to The Irish Longitudinal Study on Ageing. Information was collected on choking history, comorbidities, challenging behaviours and eating difficulties. Logistic regression was employed to determine risk factors for choking history.

RESULTS

17.3% of participants reported choking history. Eating difficulties, cerebral palsy, visual impairment, being ≥ 65 years old and antipsychotic use increased the odds of choking history.

CONCLUSIONS

Choking is prevalent in our sample. Managing choking risk requires specific responsibilities from the multidisciplinary team. Risk assessment, training staff and caregivers should be implemented in usual care.

Reflex vs. volitional cough differences amongst head and neck cancer survivors characterized by time since treatment and aspiration status

BACKGROUND

The aim of this study was to investigate differences in reflexive and volitional cough airflows in advanced stage head and neck cancer survivors as it relates to aspiration status and time since treatment. The hypothesis is that those who aspirate several years after treatment completion would demonstrate reduced airflows for all cough parameters compared to those recently status post treatment completion given the known progressive deterioration associated with radiotherapy.

METHODS

Demographic and airflow data during both reflexive and volitional cough tasks and aspiration status as determined during fiberoptic endoscopic evaluation of swallow function were collected from 33 Head and Neck Cancer (HNC) survivors.

RESULTS

Omnibus MANOVA for dependent airflow variables and independent variables aspiration status, time since treatment and cough type (reflex or volitional) was significant (F(3,1) = 184, p < 0.000) indicating that peak expiratory flow rates (PEFR) were reduced under reflex (mean PEFR 1.88 SD 0.7) versus volitional (mean PEFR 2.3, SD 0.7) cough types; reduced for aspirators versus non-aspirators (F(2,1) = 4.1, p = 0.04) and reduced for those in the subacute versus chronic phase status post Intensity Modulated Radiotherapy (IMRT) (F(2,1) = 10.05, p = 0.002).

CONCLUSION

Findings of reduced reflexive compared to volitional cough airflows in head and neck cancer survivors are consistent with those from both healthy and other diseased populations. Additional findings that aspirators demonstrate reduced cough airflows compared to non-aspirators supports the hypothesis. Surprisingly, those recently status post treatment completion show worse cough airflows compared to those remotely status post treatment completion.

Dual Tasking Influences Cough Reflex Outcomes in Adults with Parkinson's Disease: A Controlled Study

Coughing is an essential airway protective reflex. In healthy young adults, cough somatosensation changes when attention is divided (dual tasking). Whether the same is true in populations at risk of aspiration remains unknown. We present findings from a controlled study testing the effects of divided attention (via a dual-task paradigm) on measures of reflex cough in Parkinson's disease. Volunteers with Parkinson's disease (n = 14, age = 43-79 years) and 14 age-matched controls underwent five blocks of capsaicin-induced cough challenges. Within each block, capsaicin ranging from 0 to 200 μM was presented in a randomized order. Two blocks consisted of cough testing only (single task), and two blocks consisted of cough testing with simultaneous tone counting (dual task). Finally, participants completed a suppressed cough task. Measures of cough motor response, self-reported urge to cough, cough frequency, and cough airflow were collected. Historical data from healthy young adults was included for comparison. Between-group analyses revealed no differences between single- and dual-cough-task responses. However, post hoc analysis revealed a significant relationship between dual-task errors and cough frequency that was strongest in people with Parkinson's disease [p = 0.004, r² = 0.52]. Specifically, greater errors were associated with fewer reflexive coughs. Unlike healthy participants, participants with Parkinson's disease did not change the number of coughs between the single-, dual-, and suppressed-task conditions [p > 0.05]. When distracted, people with Parkinson's disease may prioritize coughing differently than healthy controls. Abnormal cortical resource allocation may be a mechanism involved in aspiration in this population.

Quantitative Videofluoroscopic Analysis of Swallowing Physiology and Function in Individuals With Chronic Obstructive Pulmonary Disease

Purpose Dysphagia is a serious extra pulmonary manifestation of chronic obstructive pulmonary disease (COPD). However, the nature of abnormalities in swallowing physiology in COPD has yet to be clearly established. We explored the frequency of swallowing measures outside the healthy reference range in adults with COPD. Method Participants were 28 adults aged 41-79 years (18 men, 20 women) with stable COPD. Disease severity was classified as GOLD (Global Initiative For Chronic Obstructive Lung Disease) Stages 1 (4%), 2 (25%), 3 (53%), and 4 (18%). Participants underwent a videofluoroscopy and swallowed 20% w/v thin barium in, followed by 20% w/v mildly, moderately, and extremely thick barium prepared with a xanthan gum thickener. Blinded duplicate ratings of swallowing safety, efficiency, kinematics, and timing were performed according to the ASPEKT method (Analysis of Swallowing Physiology: Events, Kinematics and Timing). Comparison data for healthy adults aged < 60 years were extracted from an existing data set. Chi-square and Fisher's exact tests compared the frequencies of measures falling < 1 SD/ > 1 SD from mean reference values (or < the first or > the third quartile for skewed parameters). Results Participants with COPD did not display greater frequencies of penetration-aspiration, but they were significantly more likely (p < .05) to display incomplete laryngeal vestibule closure (LVC), longer time-to-LVC, and shorter LVC duration. They also displayed significantly higher frequencies of short upper esophageal sphincter opening, reduced pharyngeal constriction, and pharyngeal residue. Conclusion This analysis reveals differences in swallowing physiology in patients with stable COPD characterized by impaired safety related to the mechanism, timing, and duration of LVC and by impaired swallowing efficiency with increased pharyngeal residue related to poor pharyngeal constriction.

Aerodigestive Disease in Dogs

Aerodigestive disorders (AeroDs) in people encompass a wide range of clinical syndromes, reflecting the complex relationship between the respiratory and digestive tracts. In veterinary medicine, aspiration is used interchangeably with aspiration pneumonia. Although aspiration pneumonia is a common disorder in dogs, it does not reflect the breadth of AeroDs. Unfortunately, AeroDs rarely are investigated in veterinary medicine because of lack of clinical recognition, limitations in available diagnostics, and the fact that AeroDs may be caused by occult digestive disease. Recognizing patients with AerodD represents an area of significant clinical importance that may provide additional areas of clinical intervention.

Effect of Brain Lesions on Voluntary Cough in Patients with Supratentorial Stroke: An Observational Study

Patients with stroke are known to manifest a decreased cough force, which is associated with an increased risk of aspiration. Specific brain lesions have been linked to impaired reflexive coughing. However, few studies have investigated whether specific stroke lesions are associated with impaired voluntary cough. Here, we studied the effects of stroke lesions on voluntary cough using voxel-based lesion-symptom mapping (VLSM). In this retrospective cross-sectional study, the peak cough flow was measured in patients who complained of weak cough (n = 39) after supratentorial lesions. Brain lesions were visualized via magnetic resonance imaging (MRI) at the onset of stroke. These lesions were studied using VLSM. The VLSM method with non-parametric mapping revealed that lesions in the sub-gyral frontal lobe and superior longitudinal and posterior corona radiata were associated with a weak cough flow. In addition, lesions in the inferior parietal and temporal lobes and both the superior and mid-temporal gyrus were associated with a weak peak cough flow during voluntary coughing. This study identified several brain lesions underlying impaired voluntary cough. The results might be useful in predicting those at risk of poor cough function and may improve the prognosis of patients at increased risk of respiratory complications after a stroke.

Detection of silent reflux events by nuclear scintigraphy in healthy dogs

Background

Reflux and aspiration in people are associated with respiratory disease, whereas approximately 50% of healthy adults microaspirate without apparent consequence. In dogs, analogous information is lacking.

Hypothesis

Healthy dogs commonly have gastroesophageal reflux and a proportion of these dogs will have laryngopharyngeal reflux with silent aspiration.

Animals

Twelve healthy, client‐owned dogs.

Methods

Prospective study: Dogs were free‐fed a meal containing (111 MBq) colloidal ⁹⁹m‐technetium phytate. Dynamic‐scans were performed 5 and 30 minutes postingestion. Time‐activity curves, reflux margination, volume, frequency, and duration were evaluated over 7 regions of interest in dorsal ± left‐lateral recumbency. Static scans (dorsal recumbency) were performed 2 and 18 hours postfeeding to detect aspiration. Reflux and aspiration were defined as counts ≥200% background activity ± decreased gastric counts. Between‐group comparisons were performed by Wilcoxon rank‐sum test or one‐way ANOVA on ranks with significance of P < .05.

Results

In this study, reflux of variable magnitude was detected in 12/12 dogs. No significant differences in outcome parameters were detected with recumbency (P > .05). Margination to the pharynx and proximal, middle, and distal esophagus was identified in 5/12, 2/12, 3/12, and 2/12 dogs, respectively. Median (IQR) reflux frequency and duration were 2 events/5 minutes (1‐3.3 events/5 minutes) and 6 seconds (4‐9 seconds) respectively. No dog had detectable aspiration.

Conclusions and Clinical Importance

Nuclear scintigraphy can document reflux in dogs. Reflux, but not aspiration, is common in healthy dogs and must be considered when interpreting results in clinically affected dogs.

An Airway Protection Program Revealed by Sweeping Genetic Control of Vagal Afferents

Sensory neurons initiate defensive reflexes that ensure airway integrity. Dysfunction of laryngeal neurons is life-threatening, causing pulmonary aspiration, dysphagia, and choking, yet relevant sensory pathways remain poorly understood. Here, we discover rare throat-innervating neurons (∼100 neurons/mouse) that guard the airways against assault. We used genetic tools that broadly cover a vagal/glossopharyngeal sensory neuron atlas to map, ablate, and control specific afferent populations. Optogenetic activation of vagal P2RY1 neurons evokes a coordinated airway defense program-apnea, vocal fold adduction, swallowing, and expiratory reflexes. Ablation of vagal P2RY1 neurons eliminates protective responses to laryngeal water and acid challenge. Anatomical mapping revealed numerous laryngeal terminal types, with P2RY1 neurons forming corpuscular endings that appose laryngeal taste buds. Epithelial cells are primary airway sentinels that communicate with second-order P2RY1 neurons through ATP. These findings provide mechanistic insights into airway defense and a general molecular/genetic roadmap for internal organ sensation by the vagus nerve.

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.

Effects of Expiratory Muscle Strength Training on Videofluoroscopic Measures of Swallowing: A Systematic Review

Purpose Expiratory muscle strength training (EMST) is increasingly utilized in dysphagia rehabilitation; however, little is known about the effects of this approach on swallowing function or physiology. We conducted a systematic review to appraise and synthesize evidence regarding the effects of EMST on videofluoroscopic measures of swallowing in individuals with medical diagnoses, in which dysphagia is a concern. Method A literature search was conducted according to Cochrane guidelines. Of 292 nonduplicate articles, 11 were judged to be relevant for review. These underwent detailed review for study quality, risk of bias evaluation, and synthesis of swallowing outcomes. Results The selected articles described EMST in a variety of patient populations using either the EMST150 or the Phillips Threshold positive expiratory pressure device. The typical protocol involved five sets of five breaths through the device (25 breaths/day), 5 days per week for 4 weeks. Exercise loads were set between 50% and 75% depending on the population, and treatment was typically supervised by a clinician weekly. The Penetration-Aspiration Scale was the most commonly reported videofluoroscopic outcome measure. Conclusions differed as to whether or not swallowing improved following a course of EMST. Differences in videofluoroscopy protocols, methods of summarizing participant performance, and statistical approaches across studies meant that meta-analysis of swallowing outcomes could not be completed. Conclusion This review failed to find clear evidence regarding the effects of EMST on videofluoroscopic measures of swallowing. Heterogeneity in the etiologies and baseline severity of dysphagia across studies and in the methods used to measure swallowing outcomes was a particular barrier to data synthesis.

Dual Tasking Influences Cough Sensorimotor Outcomes in Healthy Young Adults

Purpose Reflex cough is an essential airway protective mechanism that often occurs in the context of divided attention. The effect of divided attention on measures of reflexive cough airflow and sensitivity remains unknown. We present findings from a study testing the effects of divided attention (via a dual-task paradigm) on measures of reflex cough in healthy young adults. Method Volunteers (N = 20, age = 20-40 years) underwent 4 blocks of capsaicin-induced cough challenges. Within each block, capsaicin ranging from 0 to 200 μM was presented in a randomized order. Two blocks consisted of cough testing only (single task). During the other 2 blocks, participants counted tones while simultaneously undergoing cough testing (dual task). Measures of cough motor response, self-reported urge-to-cough, cough frequency, and cough airflow were collected. Results Participants coughed more in the single-task condition compared to the dual-task condition (p ≤ .001). Participants' urge-to-cough ratings were lower in the dual-task condition (x̅ = 2, "slight") compared to the single-task condition (x̅ = 3, "moderate"; p = .007). Participants' cough reflex sensitivity thresholds were significantly increased in the dual-task condition (p = .002). Cough peak expiratory flow rates did not change between the 2 conditions (p = .34). Conclusions Somatosensation of tussive stimuli changes during dual tasking. Abnormal cortical resource allocation may be a mechanism involved in silent aspiration.

Open Mouth-Maximal Isometric Press: Development and Norms for Clinical Swallowing Evaluations and Treatment

Purpose The aims of this study were to (a) describe the development and utility of the Open Mouth-Maximal Isometric Press (OM-MIP), a tool designed for the quantitative assessment of suprahyoid-infrahyoid muscle strength; (b) examine the effects of age and sex on the OM-MIP; and (c) establish age- and sex-based OM-MIP norms. Method Two hundred sixteen healthy male and female volunteers were recruited. Participants performed the OM-MIP, and the maximum of 3 trials that were within 10% of each other was recorded. Rest between each trial was allowed to avoid fatigue. Multiple regression examined the influence of age and sex on the OM-MIP. Descriptive statistics outlined normative OM-MIP values for young adult (aged 18-39 years), middle-aged adult (aged 40-59 years), old adult (aged 60-79 years), and very old adult (aged ≥ 80 years) men and women. Two-way analysis of variance determined if normative data differed significantly between the age and sex groups. Results Age and sex significantly influenced the OM-MIP, although no significant interaction effect was identified. Women had lower mean OM-MIPs when compared with men ( p < .0005), and very old adults had lower mean OM-MIPs when compared with young ( p = .001), middle-aged ( p < .0005), and old ( p = .013) adults. Conclusions This study establishes age- and sex-based OM-MIP norms and outlines its potential utility during clinical swallowing evaluations and treatment. By providing these norms, clinicians can begin to quantitatively measure suprahyoid and infrahyoid strength, individualize resistance training programs to patients' OM-MIP 1 repetition maximum, and track strength changes over time in response to therapeutic interventions.

Central Respiration and Mechanical Ventilation in the Gating of Swallow With Breathing

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.

Cough strength and expiratory force in aspirating and nonaspirating postradiation head and neck cancer survivors

OBJECTIVE

Expiratory functions that clear aspiration from the airway are compromised in patients with neurogenic dysphagia for whom cough and expiratory force may be impaired by the primary disease process. The relationship between expiratory function, cough, and aspiration is less clear in head and neck cancer (HNC) survivors for whom the disease process does not directly impact the lower respiratory system. Our objective was to compare mechanisms of airway clearance (expiratory force and cough) with aspiration status in postradiated HNC survivors.

STUDY DESIGN

Cross-sectional study.

METHODS

One hundred and three disease-free HNC survivors ≥ 3-months postradiotherapy referred for modified barium swallow studies were prospectively enrolled regardless of dysphagia status. Maximum expiratory pressures (MEPs) and peak cough flow (PCF) measures were taken at enrollment and examined as a function of aspiration status using generalized linear regression methods.

RESULTS

Thirty-four (33%) patients aspirated. Maximum expiratory pressure and PCF demonstrated a moderate positive correlation (Pearson's r = 0.35). Adjusting for sex and age, MEPs were on average 19.2% lower (21.1 cm H₂ O, 95% confidence interval [CI] 5.3, 36.8) among aspirators. Peak cough flow was also 14.9% lower (59.6 L/minute, 95% CI 15.8, 103.3) among aspirators after adjusting for age and sex.

CONCLUSION

Expiratory functions were depressed in postradiated HNC aspirators relative to nonaspirators, suggesting that airway protection impairments may extend beyond disrupted laryngopharyngeal mechanisms in the local treatment field. Exercises to strengthen subglottic expiratory force-generating capacity may offer an adjunctive therapeutic target to improve airway protection in chronic aspirators after head and neck radiotherapy.

LEVEL OF EVIDENCE

2b. Laryngoscope, 128:1615-1621, 2018.