Immediate Effects of Sensorimotor Training in Airway Protection (smTAP) on Cough Outcomes in Progressive Supranuclear Palsy: A Feasibility Study

Motor Imagery Practice to Improve Respiratory and Cough Function

Motor imagery practice (MP), or visualizing performing a task without executing it, is an effective intervention for the limbs and tongue. However, MP of expiratory muscle strength training (EMST) and voluntary cough (VC) has not been explored. We examined the feasibility and impact of MP of VC and EMST on pulmonary and cough function in twenty community-dwelling adults. Participants underwent two baseline research evaluations of maximum expiratory and inspiratory pressure (MEP, MIP), forced vital capacity (FVC), voluntary peak expiratory flow rate (PEF), and cough spirometry. After the second research evaluation, participants underwent five weeks of MP of VC or EMST (alternating assignment, 25 repetitions, 70% training load, daily) at home with weekly telehealth sessions. Participants underwent post-treatment research evaluations of MEP, MIP, FVC, PEF, cough spirometry, and the Exercise Therapy Burden Questionnaire (ETBQ). Treatment adherence and telehealth attendance were tracked. Descriptives and Wilcoxon signed rank tests were performed. MP adherence was 95% and telehealth attendance was 91%. Median (IQR) ETBQ scores were 8 (1, 15), indicating minimal burden. Across both MP groups, increases in PEF from a handheld device (+ 13.7, 95% CI: 1.8, 25.6, p = 0.03) and from cough spirometry (+ 0.71, 95% CI: 0.05, 1.4, p = 0.04) were observed. Increases in PEF from cough spirometry (+ 1.00, 95% CI: 0.12, 1.9, p = 0.04) were observed for the MP VC group. Preliminary data demonstrate MP of VC and EMST is feasible and improves voluntary cough in community-dwelling adults. Future research is needed in larger sample sizes and patient populations with pulmonary, cough, and swallowing impairments.

Enhancing Cough Motor Learning in Parkinson's Disease Through Variable Practice During Skill Training

BACKGROUND

When re-learning a motor skill, practicing a variety of treatment targets promotes error processing and the exploration of motor control strategies, which initially disrupts accuracy during training (motor performance), but ultimately enhances generalization, retention, and transfer (motor learning). Cough skill training (CST) is feasible and efficacious to improve cough strength; however, previous studies have used the same practice target during training.

OBJECTIVES

Our goal was to examine the impact of CST with variable practice on motor performance, motor learning, and respiratory system adaptations.

METHOD

The study was a prospective three-visit single group design. Twenty individuals with Parkinson's disease (PD) and concomitant dysphagia and dystussia completed two sessions of CST involving three randomized practice targets. Cough, lung volume, and airway clearance outcomes were assessed before and after treatment sessions with long-term retention evaluated after 1 month.

RESULTS

Peak expiratory flow rate improved after CST with variable practice for voluntary single (β = 0.35 L/s) and sequential (β = 0.22 L/s) cough, which were maintained after 1 month without treatment. The ability to expel material from the upper airway demonstrated a small magnitude of improvement (β = -1.87%). During CST, participants altered lung volume based on the treatment target and lung volume decreased during reflex cough after completing CST.

CONCLUSIONS

Individuals with PD demonstrated improvements in several aspects of motor learning after two sessions of CST with variable practice. Increasing lung volume may not be an implicit strategy to upregulate voluntary cough strength in this treatment paradigm. The findings support the need for larger investigations exploring the potential benefits of this CST approach.

Dysphagia Prevalence in Progressive Supranuclear Palsy: A Systematic Review and Meta-Analysis

The objective of this systematic review was to determine the prevalence of dysphagia and aspiration in people with progressive supranuclear palsy (PSP). A search of six electronic databases was performed from inception to April 2022. No context restrictions were set. All primary research comprising figures to derive a prevalence rate were included. Two independent reviewers screened search results. Data were extracted by one reviewer. Conflicts were resolved by discussion with a third reviewer. The quality of included studies was assessed using the JBI Checklist for Prevalence Studies. From 877 studies, 12 were eligible for inclusion. Dysphagia had to be confirmed using instrumental assessments, clinical swallowing evaluation, screening, and patient-reported outcome measures (PROM). A random-effects meta-analysis calculated a pooled dysphagia prevalence in 78-89% (95% CI [60.6, 89.1], [78.9, 95.0]). depending on the chosen assessment method, and a pooled aspiration prevalence of 23.5% (95% CI [14.5, 33.7]). The included studies were of moderate quality, with high risk of selection and coverage bias and low to moderate risk of measurement bias. Dysphagia is highly prevalent in a sample of participants with mostly moderately severe PSP. Aspiration occurs in a quarter of this sample and is likely to increase as the disease progresses. Given the low general prevalence of PSP, studies remain at high risk for selection bias. Prospective research should focus on the development of dysphagia in the course of PSP and its subcategories using instrumental assessment and consider all phases of swallowing. REGISTRATION: The protocol of this systematic review was registered on the International Prospective Register of Systematic Reviews (PROSPERO) in April 2021 (registration number: CRD42021245204).

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.

A Preliminary Study of Voluntary Cough Motor Performance and Learning With Skill Training and Biofeedback

PURPOSE

Sensorimotor cough skill training (CST) has been shown to improve cough strength, as well as facilitate changes during training (i.e., motor performance) and generalization to untrained tasks (i.e., motor learning). However, there is a gap in our understanding of the effects of voluntary CST (without sensory stimuli) on motor performance and learning. Furthermore, the contribution of physiologic factors, such as lung volume, a driver of cough strength in healthy adults, and treatment-specific factors, such as biofeedback, remains unexamined.

METHOD

Twenty individuals with Parkinson's disease (PD) completed pre- and post-CST single voluntary, sequential voluntary, and reflex cough testing. Participants were randomized to biofeedback or no biofeedback groups. They completed one CST session involving 25 trials of voluntary coughs, with the treatment target set 25% above baseline peak flow. Participants were instructed to "cough hard" to exceed the target. In the biofeedback group, participants received direct visualization of the target line in real time.

RESULTS

Cough peak flow showed positive improvements in motor performance (β = .02; 95% credible interval [CI]: 0.01, 0.03) and learning (β = .26; 95% CI: 0.03, 0.47). Changes in lung volume from pre- to post-CST did not predict treatment response. No differences in treatment response were detected between the biofeedback groups.

CONCLUSIONS

A single session of voluntary CST improved voluntary cough motor performance and learning. Although lung volume increased during CST, changes to lung volume did not predict treatment response. These findings demonstrate the potential of voluntary CST to improve motor performance and motor learning among individuals with PD and cough dysfunction.

SUPPLEMENTAL MATERIAL AND OPEN SCIENCE FORM

https://doi.org/10.23641/asha.25447444.

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.

Inducing Cough Reflex by Capsaicin Spray Stimulation in Patients with Acquired Brain Injury: A Preliminary Test and Proof of Concept

Individuals with acquired brain injuries (ABIs) may experience various complications related to poor coughing or impaired cough reflex (including risk of aspiration pneumonia or respiratory infections). For this reason, cough assessment is an important component in the clinical evaluation since patients with ABI are not able to cough voluntarily due to severe motor deficits. When voluntarily coughing is not possible, it is essential for clinical practices to find a quick and minimally invasive way to induce a cough reflex. In the present study, we evaluated the cough reflex in ABI patients using a new method based on a capsaicin spray stimulation test. In total, 150 healthy controls demographically matched with 50 ABI patients were included in this study. Clinical observations demonstrated robust cough response in both healthy controls and ABI patients, as well as the safety and tolerability of capsaicin spray stimulation. ABI patients with dysphagia were characterized by slower and delayed cough responses. Further studies are needed to validate this feasible, less-invasive, and simple-to-comprehend technique in inducing cough reflex. According to this preliminary evidence, we believe that this test might be translated into a simple and effective treatment to improve reflexive cough modulation in ABI patients.

[Dysphagia in Parkinsonian Syndromes]

Dysphagia is a clinically relevant problem in Parkinson's disease as well as in atypical Parkinsonian syndromes, such as multiple system atrophy and diseases from the spectrum of 4‑repeat tauopathies, which affect most patients to a varying degree in the course of their disease. This results in relevant restrictions in daily life due to impaired intake of food, fluids, and medication with a subsequent reduction in quality of life. This article not only gives an overview of the pathophysiological causes of dysphagia in the various Parkinson syndromes, but also presents screening, diagnostic and treatment procedures that have been investigated for the different diseases.

Characterization of Ethyl Butyrate-Induced Cough Before and After Breath Control Techniques in Healthy Adults

PURPOSE

Methods for cough elicitation frequently involve aerosolized tussive agents. Here, we sought to determine whether healthy individuals demonstrate a quantifiable cough response after inhaling a volatile ester and if breath control techniques modify this chemically induced cough response.

METHOD

Sixty adult male and female participants inhaled prepared liquid dilutions of ethyl butyrate dissolved in paraffin oil at 20%, 40%, and 60% v/v concentrations in triplicate, with presentation order randomized. We delivered stimuli through a face mask connected to an olfactometer and respiratory pneumotachograph. Participants rated sensations of their urge to cough and pleasantness of the odor while cough airflow was measured. Following baseline testing, participants were randomized to implement pursed-lip breathing or slow-paced breathing after inhaling ethyl butyrate to determine the effects of breath control on cough measures.

RESULTS

Inhaled ethyl butyrate elicited cough in 70% of participants. Higher concentrations of ethyl butyrate resulted in significantly greater sensation of the urge to cough, F(2, 80) = 10.72, p < .001, and significantly more generated coughs, F(2, 63) = 13.14, p < .001. Compared to baseline, participants rated significantly decreased urge to cough during breath control techniques, F(1, 40) = 11.01, p = .0019. No significant changes were observed in the number of generated coughs between baseline and breath control techniques, F(1, 31) = 7.23, p = .01.

CONCLUSIONS

Airborne ethyl butyrate is a tussigenic agent in humans. Our findings provide opportunities for future research directions in normal and disordered cough responses to volatile compounds.

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.

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.