Sequential voluntary cough and aspiration or aspiration risk in Parkinson's disease

Airway mechanics alters generation of cough motor pattern

Effects of sequential increase in airway resistance: no, low (5 kPa.s/l), high (24 kPa.s/l), and complete block in the inspiratory or expiratory phase of mechanically induced cough on the cough motor pattern were studied in 16 anesthetized (pentobarbital) spontaneously breathing cats (3.70±0.15 kg, 11♂, 5♀). Esophageal pressure and electromyographic activities of the diaphragm during inspiration and abdominal muscles during expiration were analyzed. No significant changes in the number of coughs occurred. Inspiratory occlusion caused a prolongation of cough inspiratory phase, cough inspiratory diaphragm activity, and all cough-related activity. Inspiratory occlusion along with high resistance increased inspiratory esophageal pressure amplitude, total cough cycle duration and the time between maximum activity of the diaphragm and abdominal muscles. High expiratory resistance and occlusion resulted in increased cough expiratory esophageal pressure amplitude, a longer active portion of cough expiration, and cough abdominal activity. Expiratory occlusion also prolonged cough expiratory phase, all cough activity, and total cough cycle. Significantly increased airway resistance and occlusion induce secondary, in addition to mechanical, changes in cough by significantly modulating the generated cough motor pattern. A certain level of resistance appears to be successfully compensated, resulting in minimal changes in coughing characteristics, including expiratory airflow and the rising time of the airflow. Afferent feedback from the respiratory tract, particularly volume feedback, represents a significant factor in modulating cough, mainly under various pathological conditions in the respiratory system.

Sensorimotor Cough Dysfunction in Cerebellar Ataxias

Cerebellar ataxias are neurological conditions with a high prevalence of aspiration pneumonia and dysphagia. Recent research shows that sensorimotor cough dysfunction is associated with airway invasion and dysphagia in other neurological conditions and may increase the risk of pneumonia. Therefore, this study aimed to characterize sensorimotor cough function and its relationship with ataxia severity. Thirty-seven participants with cerebellar ataxia completed voluntary and/or reflex cough testing. Ataxia severity was assessed using the Scale for the Assessment and Rating of Ataxia (SARA). Linear multilevel models revealed voluntary cough peak expiratory flow rate (PEFR) estimates of 2.61 L/s and cough expired volume (CEV) estimates of 0.52 L. Reflex PEFR (1.82 L/s) and CEV (0.34 L) estimates were lower than voluntary PEFR and CEV estimates. Variability was higher for reflex PEFR (15.74% coefficient of variation [CoV]) than voluntary PEFR (12.13% CoV). 46% of participants generated at least two, two-cough responses following presentations of reflex cough stimuli. There was a small inverse relationship between ataxia severity and voluntary PEFR (β = -0.05, 95% CI: -0.09 - -0.01 L) and ataxia severity and voluntary CEV (β = -0.01, 95% CI: -0.02 - -0.004 L/s). Relationships between reflex cough motor outcomes (PEFR β = 0.03, 95% CI: -0.007-0.07 L/s; CEV β = 0.007, 95% CI: -0.004-0.02 L) and ataxia severity were not statistically robust. Results indicate that voluntary and reflex cough sensorimotor dysfunction is present in cerebellar ataxias and that increased severity of ataxia symptoms may impact voluntary cough function.

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.

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.

Assessment of the Sensitivity of the Vocal Tract in Parkinson Disease by Nasal Video Endoscopy

Introduction  Sensory deficits of the upper airways are common in people with Parkinson disease. Compounded by considerable deterioration of the swallowing function, these deficits may contribute to the elevated rates of morbidity and mortality among this population. Objective  To examine the sensitivity of the vocal tracts of people with Parkinson disease using nasal videoendoscopy and to compare the results with paired controls. Methods  The present was a prospective, observational, case-control study. Sensitivity assessments were conducted in a sample of 24 people divided into 2 groups: one group of 12 patients with Parkinson's disease, and a control group with 12 healthy subjects. The study group also underwent a fiberoptic endoscopic evaluation of swallowing and answered the Swallowing Disturbance Questionnaire (SQD) to detect dysphagia. Results  There was a significant difference ( p  < 0.05) in the region of the arytenoid cartilages, showing that sensitivity was better preserved among the control group, and that sensitivity deficits were present in the study group. The qualitative results showed sensorial impairment in the study group than in the control group regarding the base of the tongue, the vestibular folds, and the vocal folds. The study group showed self-awareness regarding the deficits in the swallowing function, but there was no statistically significant association between swallowing function deficits and deterioration of sensorial function among them. Conclusions  Sensorial deficits were present in the study group when compared to the healthy subjects, mainly in the qualitative evaluation.

Dysphagia in Parkinson Disease: Part I - Pathophysiology and Diagnostic Practices

Purpose of Review

Dysphagia affects the majority of individuals with Parkinson disease (PD) and is not typically diagnosed until later in disease progression. This review will cover the current understanding of PD pathophysiology, and provides an overview of dysphagia in PD including diagnostic practices, gaps in knowledge, and future directions.

Recent Findings

Many non-motor and other motor signs of PD appear in the prodrome prior to the manifestation of hall- mark signs and diagnosis. While dysphagia often presents already in the prodrome, it is not routinely addressed in standard neurology examinations.

Summary

Dysphagia in PD can result in compromised efficiency and safety of swallowing, which significantly contributes to malnutrition and dehydration, decrease quality of life, and increase mortality. The heterogeneous clinical presentation of PD complicates diagnostic procedures which often leads to delayed treatment. Research has advanced our knowledge of mechanisms underlying PD, but dysphagia is still largely understudied, especially in the prodromal stage.

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.

Characterizing Swallowing Impairment in a Post-Lung Transplant Population

BACKGROUND

Lung transplant recipients carry significant pre- and post-lung transplant dysphagia risk factors related to altered respiratory-swallow coordination as well as acute injury and decompensation resulting in the acute post-lung transplant recovery period. However, we are only beginning to understand the potential physiological contributors to altered swallowing in this population.

METHOD

A retrospective, cross-sectional, cohort study of post-lung transplant patients was performed. All participants received a modified barium swallow study (MBSS) as part of standard care during their acute hospitalization using the Modified Barium Swallow Impairment Profile (MBSImP) protocol and scoring metric. A combination of MBSImP scores, Penetration-Aspiration Scale (PAS) scores, Functional Oral Intake Scale (FOIS) scores, International Dysphagia Diet Standardization Initiative (IDDSI) scale levels, and the time from lung transplant to MBSS was collected, as well as measures of swallowing impairment and swallowing-related outcomes. Differences in swallowing physiology and swallowing-related outcomes between participants with typical versus atypical PAS were explored.

RESULTS

Forty-two participants met our prespecified inclusion criteria. We identified atypical laryngeal penetration and/or aspiration in 52.4% of our post-lung transplant cohort. Silent aspiration occurred in 75% of those patients who aspirated. Comparing typical versus atypical PAS scores, we found statistically significant associations with laryngeal elevation (Component 8), p < .0001; anterior hyoid excursion (Component 9), p = .0046; epiglottic movement (Component 10), p = .0031; laryngeal vestibule closure (Component 11), p < .0001; pharyngeal stripping (Component 12), p = .0058; pharyngeal total scores, p = .0001; FOIS scores, p = .00264; and IDDSI liquid levels, p = .0009.

CONCLUSIONS

Swallowing impairment resulting in abnormal bolus invasion is prevalent in post-lung transplant patients. Airway invasion in this cohort was related to pharyngeal swallow impairment and resulted in modified oral intake. Our findings help expand upon prior literature, which only reported the incidence of aspiration and pathological laryngeal penetration. Our results suggest that the potential for aerodigestive system impairment and negative sequela should not be underestimated in the post-lung transplant population.

Analysis of Dysphagia and Cough Strength in Patients with Unilateral Vocal Fold Paralysis

The association between swallowing function and cough strength in patients with unilateral vocal fold paralysis (UVFP) is unknown. We evaluated the relationship between voluntary cough strength and dysphagia among patients with UVFP (UVFP group) by comparing their data with that of corresponding healthy participants (healthy control [HC] group) in a prospective observational study. From February 1st, 2018 to March 30th, 2019, we recruited patients with a voice disorder due to UVFP, who were referred to our university hospital. Patients with a history of laryngeal surgery, vagal nerve paralysis, or cardiac and respiratory failure were excluded. Descriptive and clinical data regarding swallowing, voice, and cough peak flow (CPF) were collected as a measure of cough strength. The UVFP group comprised six women and seven men (median age, 68.0 years), and the HC group comprised six women and eight men (median age 65.5 years). The groups differed significantly in the Eating Assessment Tool (EAT)-10 scores and CPF rates (P < 0.001). Among patients with UVFP, 84.6% had an abnormal EAT-10 score of ≥ 3. Additionally, 16.7% of the patients exhibited liquid aspiration with contrast medium on a videofluorographic swallowing study (VFSS). There was no correlation between the CPF values, EAT-10 scores, or the VFSS results. Therefore, patients with severe UVFP, whose condition had been fixed, had difficulties when swallowing (85% of cases), and some even presented with aspiration on VFSS (20% of cases), while receiving a regular diet.

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.

Relationship between dysphagia and surgical treatment for supraglottic laryngeal carcinoma: A meta-analysis

OBJECTIVE

To systematically evaluate differences in swallowing disorder-related manifestations in patients with supraglottic laryngeal cancer, who underwent traditional open partial horizontal laryngectomy (OPHL) and endoscopic supraglottic laryngectomy (ESL).

METHODS

A systematic review of the literature and a meta-analysis were performed. The CNKI, Wan Fang, PubMed, EMBASE, Cochrane Library, Web of Science, and Clinical Trials databases for clinical studies data sources were investigated. The efficiency of recovery, postoperative swallowing function, and complications related to dysphagia were investigated to compare the effects of surgical procedures.

RESULTS

The meta-analysis included 8 studies with 281 patients. ESL surgery played a positive role in the recovery of patients. Preservation of the anterior epiglottic space, ventricular band, and arytenoid cartilage without destroying the external framework of the larynx can effectively reduce the risk of aspiration pneumonia in patients.

CONCLUSIONS

ESL has advantages in postoperative recovery and retention of swallowing function in patients with supraglottic laryngeal cancer.

A Decision Guide for Assessing the Recently Extubated Patient's Readiness for Safe Oral Intake

BACKGROUND

Postextubation dysphagia is a known consequence of endotracheal intubation. Several risk factors for postextubation dysphagia have been identified that could be used to help determine which patients should undergo swallowing assessment by an appropriate professional.

LOCAL PROBLEM

At the authors' institution, critical care nurses, health care providers, and speech-language pathology professionals lacked a clear process for referring patients for swallowing assessment after extubation, resulting in inefficiency and confusion. Information to guide their decision-making in this area was needed. To address this need, a multidisciplinary group convened and developed a guide with specific indicators.

METHODS

A review of the literature on postextubation dysphagia was conducted to determine the most appropriate indicators for the guide, which was piloted in the medical intensive care unit. The utilization rate was calculated. Referrals to speech-language pathology professionals were tabulated before and after the project.

RESULTS

During the 11 months before implementation of the project, there were 994 speech-language pathology consultations for postextubation evaluation of swallowing. During the 11 months after implementation, there were 831 consultations, representing a 16.4% reduction. The decline in consultations resulted in cost savings in addition to preventing unnecessary testing before patients' resumption of oral intake. The utilization rate for the guide during the project was 58%.

CONCLUSION

The decision guide was an effective tool to help nurses and health care providers determine which patients should be referred to speech-language pathology professionals for swallowing assessment after extubation, facilitating the appropriate use of limited health care resources.

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.

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.

Experienced Respiratory Symptoms and the Impact on Daily Life from the Perspective of People with Parkinson's Disease: A Grounded Theory

BACKGROUND

Abnormal respiratory function tests can be observed early in the course of Parkinson's disease (PD). A better understanding of the impact of respiratory dysfunction on daily life in PD is needed to prevent later occurring complications as a (aspiration) pneumonia.

OBJECTIVE

To explain which respiratory symptoms people with PD or a form of atypical parkinsonism experience and how these symptoms impact on their daily lives.

METHODS

This qualitative study used a grounded theory approach. A purposeful sample strategy was used to capture information-rich cases. Data were collected in semi-structured interviews with participants diagnosed with either PD (n = 11) or atypical parkinsonism (n = 3), all of whom had confirmed respiratory symptoms. Data were analyzed using grounded theory analysis by creating codes, categories, theoretical themes, and, ultimately, a conceptual model.

RESULTS

Four respiratory profiles emerged, describing different types of respiratory dysfunction, with various positive and negative influencing factors. First, a loss of breathing automatism was experienced. Second, episodes of breathlessness or a rapid, shallow breathing pattern were triggered by either physical exertion, fatigue, or postural deformities. Third, stress and anxiety also triggered episodes of breathlessness. Fourth, a decreased cough strength and frequent coughing. Based on these findings, we constructed a conceptual model that visualizes the relations between these four types of respiratory dysfunction and their impact on daily life, with 'discomfort' and 'avoidance of social activities' as crucial elements.

CONCLUSION

A tailored approach for each profile of respiratory dysfunction is recommended to improve respiratory dysfunction and to reduce its social impact in people with PD.

Effects of Respiratory Muscle Strength Training on Respiratory-Related Impairments of Parkinson's Disease

In addition to typical motor dysfunction, Parkinson's disease is also characterized by respiratory-related dysfunction. As a means of rehabilitation, respiratory muscle strength training (RMST) has been applied to restore Parkinson's disease (PD) functions. However, the current clinical value of RMST in the application for PD has not been widely established. This article aims to review the research progress of the application of RMST in PD rehabilitation to provide new sight into respiratory-related impairments management in people with PD.

Voluntary Cough Effectiveness and Airway Clearance in Neurodegenerative Disease

PURPOSE

Voluntary cough dysfunction is highly prevalent across multiple patient populations. Voluntary cough has been utilized as a screening tool for swallowing safety deficits and as a target for compensatory and exercise-based dysphagia management. However, it remains unclear whether voluntary cough dysfunction is associated with the ability to effectively clear the airway.

METHOD

Individuals with neurodegenerative disorders performed same-day voluntary cough testing and flexible endoscopic evaluations of swallowing (FEES). Participants who were cued to cough after exhibiting penetration to the vocal folds and/or aspiration with thin liquids during FEES met inclusion criteria. One-hundred and twenty-three trials were blinded, and the amount of residue before and after a cued cough on FEES was measured with a visual analog scale. Linear and binomial mixed-effects models examined the relationship between cough airflow during voluntary cough testing and the proportion of residue expelled.

RESULTS

Peak expiratory flow rate (p = .004) and cough expired volume from the entire epoch (p = .029) were significantly associated with the proportion of aspiration expelled from the subglottis. Peak expiratory flow rate values of 3.00 L/s, 3.50 L/s, and 5.30 L/s provided high predicted probabilities that ≥ 25%, ≥ 50%, and ≥ 80% aspirate was expelled. Accounting for depth of aspiration significantly improved model fit (p < .001).

CONCLUSIONS

These findings suggest that voluntary cough airflow is associated with cough effectiveness to clear aspiration from the subglottis, although aspiration amount and depth may play an important role in this relationship. These findings provide further support for the clinical utility of voluntary cough in the management of dysphagia.

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.

Global Physiology and Pathophysiology of Cough: Part 2. Demographic and Clinical Considerations: CHEST Expert Panel Report

BACKGROUND

Cough characteristics vary between patients, and this can impact clinical diagnosis and care. The purpose of part two of this state-of-the-art review is to update the American College of Chest Physicians (CHEST) 2006 guideline on global physiology and pathophysiology of cough.

STUDY DESIGN AND METHODS

A review of the literature was conducted using PubMed and MEDLINE databases from 1951 to 2019 using prespecified search terms.

RESULTS

We describe the demographics of typical patients with cough in the clinical setting, including how cough characteristics change across age. We summarize the effect of common clinical conditions impacting cough mechanics and the physical properties of mucus on airway clearance.

INTERPRETATION

This is the second of a two-part update to the 2006 CHEST cough guideline; it complements part one on basic phenomenology of cough by providing an extended clinical picture of cough along with the factors that alter cough mechanics and efficiency in patients. A greater understanding of the physiology and pathophysiology of cough will improve clinical management.

A multinational consensus on dysphagia in Parkinson's disease: screening, diagnosis and prognostic value

Background

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by a combination of motor and non-motor dysfunction. Dysphagia is a common symptom in PD, though it is still too frequently underdiagnosed. Consensus is lacking on screening, diagnosis, and prognosis of dysphagia in PD.

Objective

To systematically review the literature and to define consensus statements on the screening and the diagnosis of dysphagia in PD, as well as on the impact of dysphagia on the prognosis and quality of life (QoL) of PD patients.

Methods

A multinational group of experts in the field of neurogenic dysphagia and/or PD conducted a systematic revision of the literature published since January 1990 to February 2021 and reported the results according to PRISMA guidelines. The output of the research was then analyzed and discussed in a consensus conference convened in Pavia, Italy, where the consensus statements were drafted. The final version of statements was subsequently achieved by e-mail consensus.

Results

Eighty-five papers were used to inform the Panel’s statements even though most of them were of Class IV quality. The statements tackled four main areas: (1) screening of dysphagia: timing and tools; (2) diagnosis of dysphagia: clinical and instrumental detection, severity assessment; (3) dysphagia and QoL: impact and assessment; (4) prognostic value of dysphagia; impact on the outcome and role of associated conditions.

Conclusions

The statements elaborated by the Consensus Panel provide a framework to guide the neurologist in the timely detection and accurate diagnosis of dysphagia in PD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10739-8.

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.

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.

Characterizing Quality of Life in Caregivers of People with Parkinson's Disease and Dysphagia

Caring for a family member with dysphagia can negatively impact caregiver wellbeing, although little is known about how dysphagia severity or specific symptoms influence this. The purpose of this study was to examine how objective measures of dysphagia in people with Parkinson's disease influenced their caregivers' quality of life. Fifty caregivers (mainly spouses) of people with Parkinson's disease completed a caregiver quality of life survey. Results were compared to medical chart reviews, interviews, and instrumental evaluations of swallowing from the care recipients. Outcomes included caregiver quality of life score, ratings of airway invasion and pharyngeal residue, and Parkinson's disease duration. Descriptive and regression analyses were completed. All caregivers reported reduced quality of life, with 28% having severely disturbed adaptation. Every care recipient with Parkinson's disease demonstrated airway invasion and/or pharyngeal residue. Together, the combination of older care recipient age and longer disease duration was associated with poorer caregiver quality of life [adj. R² = 0.10-0.12, p = 0.03-0.4]. Neither airway invasion nor pharyngeal residue was related to caregiver quality of life (p > 0.05). Findings confirmed that caregivers of people with Parkinson's disease and dysphagia experience reduced quality of life; however, current methods of assessing caregivers' quality of life may not adequately account for dysphagia-specific burden. Results highlight the urgent need for the development of dysphagia-specific assessments of caregivers' quality of life to facilitate identification of high-risk caregivers and aid the development of support systems to improve health outcomes for caregivers and care recipients.

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.

Single and sequential voluntary cough in children with chronic spinal cord injury

We investigated the impact of spinal cord injury (SCI) on cough capacity in 10 children (Mean ± SD, age 8 ± 4 years) and compared it to 15 typically developing children (age 8 ± 3 years). Participants underwent spirometry, single and sequential cough assessment with surface-electromyography from respiratory muscles. Inspiratory phase duration, inspiratory phase peak flow, inspiratory phase rise time, compression phase duration, expiratory phase rise time, expiratory phase peak airflow (EPPF) and cough volume acceleration (CVA) parameters of single and sequential cough were measured. Root mean square (RMS) values of right pectoralis-major, intercostal, rectus-abdominus (RA), and oblique (OB) muscles were calculated and mean of three trials were compared. The significance criterion was set at P < 0.05. The SCI group produced significantly lower lung volumes, EPPF, CVA, and RMS values of RA and OB during expiratory phases of single and sequential coughs. The decrease in activation in expiratory muscles in the SCI group accounts for the impaired expiratory flow and may contribute to risk of respiratory complications.

The Effects of Respiratory Training in Parkinson's Disease: A Systematic Review

BACKGROUND

Signs of respiratory dysfunction can be present already early in the course of Parkinson's disease (PD). Respiratory training could alleviate this, but its effectiveness is not well understood.

OBJECTIVE

The purpose of this systematic review is to review the efficacy of different respiratory training interventions in PD.

METHODS

A search strategy was performed in four databases: PubMed, Physiotherapy Evidence Database (PEDro), Cochrane Library, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Methodological quality of original full-text articles was assessed using the Cochrane Risk of Bias tool for randomized controlled trials (RCTs) and the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool for the controlled trials (CTs). Levels of evidence were rated by the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Six papers reporting on four randomized controlled trials and another four controlled trials were included. Positive effects were reported for inspiratory muscle strength training (IMST), expiratory muscle strength training (EMST), air stacking, breath-stacking, incentive spirometry and postural training on respiratory muscle strength, swallowing safety, phonatory aspects and chest wall volumes. Best methodological quality was found for breath-stacking and incentive spirometry. Best levels of evidence were found for EMST, IMST and EMST plus air stacking.

CONCLUSION

Respiratory training shows positive effects and should be considered when people with PD experience respiratory dysfunction. Future studies should focus on standardizing both training devices, instruments to measure outcomes and intervention protocols to further increase the level of evidence.

Variability of Voluntary Cough Airflow in Healthy Adults and Parkinson's Disease

Cough is an important airway protective behavior responsible for ejecting material from the airway to prevent pneumonia, a leading cause of death in older adults and individuals with Parkinson's disease (PD). Variability of motor performance for both spinal and bulbar functions has been documented; however, there are no studies examining variability of cough motor control in PD and healthy controls. The present study examined the effects of age and PD on variability of voluntary cough performance. Twenty-five healthy younger adults (HYA), 26 healthy older adults (HOA), and 16 participants with PD completed three trials of sequential voluntary cough with spirometry. Coefficients of variation were used to examine variability between groups. Increased variability of cough expired volume (p = 0.012) and inspiratory volume (p = 0.006) was appreciated in HOAs compared to HYAs. Participants with PD demonstrated increased variability of cough expired volume (p = 0.029), peak expiratory flow rise time (p = 0.016), and cough volume acceleration (p = 0.034) compared to HOAs. Though participants with PD descriptively demonstrated increased peak expiratory flow rate compared to HOAs, this finding was statistically nonsignificant after adjusting for multiple comparisons (p = 0.072). This study identified that variability in cough airflow increases in healthy aging and Parkinson's disease. These motor control impairments may be attributed to age and disease-related sensorimotor changes in the peripheral and central nervous system. Future research will be necessary to examine the relationship between inconsistent cough motor output, airway invasion, and aspiration pneumonia in PD.

Swallowing-related quality of life among oral-feeding Chinese patients with Parkinson's disease - a preliminary study using Chinese SWAL-QOL

PURPOSE

The objective of the present study is to evaluate swallowing-related quality of life in Chinese patients with Parkinson's disease (PD) using the validated Chinese version of the Swallowing Quality-of-Life Questionnaire (C-SWAL-QOL) and factors associated with swallowing-related quality of life, including age, disease duration, and severity of depression by 15-item Geriatric Depression Scale in Chinese version (GDS-C).

METHODS

C-SWAL-QOL was administered to 67 Chinese patients with PD. Upon completion of C-SWAL-QOL, they completed the 15-item GDS-C. Spearman's Rho correlation analyses were performed to examine the relationship between the 10-subscale scores of C-SWAL-QOL and (1) age, (2) disease duration, and (3) depression.

RESULTS

Among the subscales in C-SWAL-QOL, sleep, fatigue, eating duration, and communication were the most severely affected. Significant relationships existed between composite C-SWAL-QOL score, total C-SWAL-QOL score, Dysphagia Symptom Battery (DSB) core, and depression. Significant relationships were also observed between depression and the following subscales: communication, fear, mental health, social functioning, and fatigue. Yet, no relationships existed between score of C-SWAL-QOL and age or disease duration in PD.

CONCLUSIONS

Considering the goal of dysphagia intervention is to improve swallowing safety and efficiency and ultimately enhance patients' QOL, clinicians should consider using C-SWAL-QOL in clinical practice to measure swallowing outcomes and to better understand treatment effectiveness.Implications for rehabilitationDysphagia-related patient-reported outcome (PRO) measures such as Swallowing Quality-of-Life Questionnaire (SWAL-QOL) are the cornerstone to systematically collecting patient-centered data and monitoring rehabilitation outcomes.Based on the scores of Chinese Parkinson's disease (PD) patients in an oral feeding population indicated in the current study, treatment goal and rehabilitation plan can be set.Chinese patients with Parkinson's disease might benefit from a rehabilitation program focusing on the most severely affected subscales in C-SWAL-QOL.

Sex-specific vagal and spinal modulation of swallow and its coordination with breathing

Swallow-breathing coordination is influenced by changes in lung volume, which is modulated by feedback from both vagal and spinal sensory afferents. The purpose of this study was to manipulate feedback from these afferents, with and without a simultaneous mechanical challenge (chest compression), in order to assess the influence of each sensory pathway on swallow in rats. We hypothesized that manipulation of afferent feedback would shift the occurrence of swallow toward the inspiratory phase of breathing. Afferent feedback was perturbed by lidocaine nebulization, extra-thoracic vagotomy, or lidocaine administration to the pleural space in sodium pentobarbital anesthetized rats (N = 43). These different afferent perturbations were performed both in control conditions (no chest compression), and with chest compression. Manipulating pulmonary stretch receptor-mediated volume feedback in male animals decreased swallow occurrence. Female rats appear to rely more on spinal afferent feedback, as swallow occurrence shifted to late expiration with chest compression and vagotomy or lidocaine injections. Results suggest that sex-specific mechanisms modulate swallow-breathing coordination, and that vagal feedback is inhibitory to swallow-related muscles, while spinal feedback from pleural afferents has excitatory effects. This study supports the theory that a balance of vagal and spinal afferent feedback is necessary to maintain an optimal swallow pattern and swallow-breathing coordination.

A comprehensive review of the diagnosis and treatment of Parkinson's disease dysphagia and aspiration

INTRODUCTION

Bulbar dysfunction is common in Parkinson's disease (PD) with more than 80% of affected individuals developing dysphagia during the course of the disease. Symptoms can begin in the preclinical stage and individuals may remain clinically asymptomatic for years. Furthermore, patients may be unaware of swallowing changes, which contributes to the difference between the prevalence of self-reported dysphagia and deficits identified during instrumental evaluations. Dysphagia is underrecognized and contributes to the development of aspiration pneumonia which is the leading cause of death in PD. Dysphagia in PD is complex and not completely understood. Both dopaminergic and nondopaminergic pathways likely underpin dysphagia.

AREAS COVERED

This comprehensive review will cover the epidemiology, pathophysiology, clinical evaluation, and expert management of dysphagia and aspiration in patients with PD.

EXPERT OPINION

A multidisciplinary team approach is important to properly identify and manage PD dysphagia. Regular clinical screenings with objective instrumental assessments are necessary for early detection of dysphagia. Studies are needed to better understand the mechanism(s) involved in PD dysphagia, establish markers for early detection and progression, and develop evidence-based treatment options.

Pneumonia risk and its associated factors in Parkinson's disease: A National Database Study

BACKGROUND

Despite pneumonia being an emerging burden on Parkinson's disease patients, there is essentially nothing known on whether they are at an increased risk of pneumonia occurrence and their associated factors.

OBJECTIVES

To determine whether Parkinson's disease is associated with the risk of pneumonia and its associated factors.

METHODS

Using nationwide database that covers the whole population in South Korea from 2002 to 2017, we identified newly diagnosed Parkinson's disease patients in 2004-2006, and selected four age- and sex-matched controls for each patient from the general population. From these patients and controls, we identified pneumonia occurrence until the end of the study period, and plotted Kaplan-Meier curves and Cox proportional hazards model to determine its risk.

RESULTS

We identified 10,159 Parkinson's disease patients and matched 39,574 controls. These patients showed a higher incidence rate than controls (11.21 vs. 3.61 events/1000 person-years) throughout the study period, and were at an increased risk of pneumonia (hazard ratio = 2.26; 95% CI, 2.17-2.36) even after adjusting for confounders. Old age, male sex, region of residence, diabetes mellitus, congestive heart failure, tuberculosis, atrial fibrillation, chronic kidney disease, cerebrovascular disease, dementia, chronic obstructive pulmonary disease, seizure disorder and antidiabetic drug usage were all associated with a higher risk of pneumonia, while dyslipidemia and antihypertensive medication usage lowered the risk.

CONCLUSIONS

Parkinson's disease patients may be more likely to experience pneumonia compared to the general population throughout the disease course from diagnosis. Therefore, physicians should focus on the modifiable risk factors of pneumonia in such patients.

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

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

The assessment of the peak of reflex cough in subjects with acquired brain injury and tracheostomy and healthy controls

INTRODUCTION

There is no standard procedure to evaluated the peak of reflex cough flow (PCF-reflex) in the literature, which is important assessment in subjects with acquired brain injury and tracheostomy cannula. The present study aims to investigate the PCF of the reflex cough in a broad sample of healthy controls and, furthermore, the presence and the strength of voluntary and reflex cough in subjects with ABI with tracheostomy cannula.

MATERIALS AND METHODS

We recruited 147 participants including the healthy subjects (n = 105) and acquired brain injury subjects (n = 43), who underwent respiratory assessment: the Tidal Volume, Forced Vital Capacity, PCF of voluntary cough (PCF-voluntary) and PCF-reflex (using a spirometer connected with a nebulizer by a bidirectional).

RESULTS

The PCF-reflex of controls and subjects was significant lower than the PCF-voluntary (P < 0.01). The PCF-voluntary was not assessed in 26 (60.5 %) subjects due to severe cognitive deficit. In subjects without cognitive deficits (n = 17; 39.5 %), it was significantly lower than in healthy controls (p < 0.01). In contrast, the PCF-reflex was completed in all subjects and it was not significantly different from healthy controls. Furthermore, the strength of the PCF-reflex decreased with increasing inhalation numbers of nebulised air.

CONCLUSION

Reflex cough behaviour differs largely from voluntary cough and the PCF results reflect this great discrepancy. PCF-reflex could be useful parameter for assessing the airway protection whereas PCF-voluntary for measuring airway clearance.

Effects of Expiratory Muscle Training and Air Stacking on Peak Cough Flow in Individuals with Parkinson's Disease

The purpose of this study was to investigate the effects of air stacking (AS) and an expiratory muscle training (EMT) program to increase voluntary and reflex peak cough flow (PCF) in individuals with Parkinson's disease. Participants were allocated to the control (n = 11), EMT (n = 11), or EMT + AS group (n = 11). All groups performed EMT (5 sets of 5 repetitions), 6 times a week for 2 months. The control group used a fixed resistance, EMT plus AS and EMT groups used a progressively increased resistance. The EMT plus AS group additionally performed 10 series of three to four lung insufflations using a manual resuscitator bag. Voluntary and reflex PCF, maximum expiratory pressure, and slow vital capacity were assessed before and after training. EMT plus AS was more beneficial than EMT alone for improving reflex and voluntary PCF. The effect of the EMT plus AS was greater for reflex PCF than for voluntary PCF.

Use of the Penetration-Aspiration Scale in Dysphagia Research: A Systematic Review

The penetration-aspiration scale (PAS) is an 8-point scale used to characterize the depth and response to airway invasion during videofluoroscopy. Though widely used in the field of deglutition, there is a lack of consensus regarding the statistical properties of the scale. In order to better understand the state of the literature and the statistical use of the PAS, a systematic review was undertaken to descriptively examine trends in statistical and reporting practices of the PAS since its inception. Online databases were searched for studies citing the original PAS article, which yielded 754 unique articles. Of these, 183 studies were included in the review. Results showed inconsistencies in the statistical use of the scale; 79 studies treated the PAS as ordinal, 71 as categorical, and 49 as interval. Ten types of categorizations were identified. Reporting of power analyses (9%), as well as inter- (26%) and intra-rater (17%) reliability, was uncommon. Among studies that administered multiple bolus volumes or consistencies, 55% reported PAS analyses at the participant/group level only. This review confirms the existence of discrepancies in the statistical treatment of the PAS. A lack of consensus among researchers limits comparisons between studies. The approach to handling this scale dictates the statistical tests used, potentially affecting results and interpretations. Consistent application of statistically sound approaches to PAS analyses is vital for the future of deglutition research.

Management of Dysphagia in Acquired and Progressive Neurologic Conditions

As the act of deglutition involves much of the central and peripheral nervous systems, neurologic disease can affect swallowing behaviors ranging from mild to profound in severity. The key in working with neurogenic dysphagia is to have a solid foundation in normal swallowing processes, including neural control. Within this framework, then, understanding how the neurologic condition affects neural control will guide hypothesis-based assessment and evidence-based treatment. The purpose of this article is to provide an overview of evaluation and treatment of neurogenic dysphagia in adult populations as well to propose assessment of co-occurring speech, language, and airway compromise. Furthermore, it is vital to be familiar with ethical decision making and end-of-life issues. Continuing education in the form of research articles, conferences, and professional discussion boards is useful in maintaining a high level of service delivery. Whenever possible, an inter- or transdisciplinary approach is recommended.

Characteristics of impaired voluntary cough function in individuals with amyotrophic lateral sclerosis

OBJECTIVE

Although cough impairment (dystussia) is common in individuals with amyotrophic lateral sclerosis (ALS) and contributes to a reduced physiologic capacity to defend the airway, characteristics of dystussia have not yet been delineated. Therefore, we aimed to compare voluntary cough spirometry airflow patterns between individuals with ALS and healthy age and gender-matched controls.

METHODS

Thirty-two individuals with a diagnosis of probable-definite ALS (El-Escorial Criterion) and 29 healthy age and gender-matched controls underwent voluntary cough spirometry testing. Two blinded raters derived six objective voluntary cough airflow measures including: peak inspiratory phase duration, peak inspiratory flow rate, compression phase duration, peak expiratory rise time, peak expiratory flow rate, and cough volume acceleration. Independent samples t-tests with Cohen's d effect sizes were performed between Healthy versus ALS groups for cough metrics (alpha =0.05).

RESULTS

ALS individuals demonstrated prolonged inspiratory phase and expiratory phase rise time durations, reduced inspiratory and expiratory flow rates, and lower cough volume acceleration during voluntary cough production compared with healthy controls (p < 0.05). No differences in compression phase duration were observed (p > 0.05).

CONCLUSIONS

This study compared characteristics of voluntary cough airflow patterns of individuals with ALS to healthy-matched controls. Findings identified impairments in both inspiratory and expiratory voluntary cough airflow, resulting in slower, weaker, and thus less effectiveness voluntary cough production in ALS individuals. These data afford insight into the impaired physiology underlying inadequate airway clearance and secretion management in individuals with ALS.

Posture and firmness changes in a pressure-relieving air mattress affect cough strength in elderly people with dysphagia

Dysphagia is the major pathophysiologic mechanism leading to aspiration pneumonia in the elderly. Elderly people with dysphagia who show low levels of the cough peak flow (CPF) are at greater risk for aspiration pneumonia. It has been reported that CPF values were significantly lower in the “soft” versus “hard” mode of a pressure-relieving air mattress in healthy volunteers in a supine position. Parameters such as spinal curvature, however, were not evaluated in detail. In this study, we clarified whether the changes in posture associated with two different firmness levels of a pressure-relieving air mattress were associated with cough production and related factors in the elderly with dysphagia. The body sinking distance, pelvic tilt angle, and immersion of the lumbar spine were measured to evaluate changes in posture. Forty subjects met the study criteria for dysphagia. The “soft” mode showed significantly lower CPF values than the “hard” mode (soft 274.9 ± 107.2 L/min vs. hard 325.0 ± 99.5 L/min, MD 50.0 95%CI 33.1–66.9 P < 0.001). Values of forced vital capacity (FVC) and maximal inspiratory pressure (PImax) were significantly lower in the “soft” mode than in the “hard” mode (MD 0.10 95%CI 0.04–0.17, P = 0.002, MD 3.2 95%CI 0.9–5.5, P = 0.007, respectively). Although there was no significant difference between the two firmness levels, maximal expiratory pressure (PEmax) values also tended to be lower in the “soft” than in the “hard” mode, (MD 2.9 95%CI -0.6–6.3 P = 0.1). At both firmness levels, CPF values were significantly correlated with FVC, PImax, and PEmax. The difference in sinking distance in the anterior superior iliac spine was significantly larger than that in the lesser tubercle of the humerus and patella. Additionally, in the soft mode, the pelvic tilt angle and contact area around the lumbar spine were significantly larger than those observed in the “hard” mode. Parameters associated with the production of cough, including inspiratory muscle strength, lung volume, and ultimately CPF, may be affected by immersion of the lumbar spine and curvature of the spine that results from the “soft” mode in elderly patients with dysphagia.

Strategies for the Integration of Cough and Swallow to Maintain Airway Protection in Humans

PURPOSE

Airway protective behaviors, like cough and swallow, deteriorate in many populations suffering from neurologic disorders. While coordination of these behaviors has been investigated in an animal model, it has not been tested in humans.

METHODS

We used a novel protocol, adapted from previous work in the cat, to assess cough and swallow independently and their coordination strategies in seven healthy males (26 ± 6 years). Surface electromyograms of the submental complex and external oblique complex, spirometry, and thoracic and abdominal wall kinematics, were used to evaluate the timing of swallow, cough, and breathing as well as lung volume (LV) during these behaviors.

RESULTS

Unlike the cat, there was significant variability in the cough-swallow phase preference; however, there was a targeted LV range in which swallow occurred.

CONCLUSION

These results give insight into the differences between the cat and human models in airway protective strategies related to the coordination of cough and swallow behaviors, allowing for better understanding of dystussia and dysphagia.

Aspiration Pneumonia and Related Syndromes

Aspiration is a syndrome with variable respiratory manifestations that span acute, life-threatening illnesses, such as acute respiratory distress syndrome, to chronic, sometimes insidious, respiratory disorders such as aspiration bronchiolitis. Diagnostic testing is limited by the insensitivity of histologic testing, and although gastric biomarkers for aspiration are increasingly available, none have been clinically validated. The leading mechanism for microaspiration is thought to be gastroesophageal reflux disease, largely driven by the increased prevalence of gastroesophageal reflux across a variety of respiratory disorders, including chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis, and chronic cough. Failure of therapies targeting gastric acidity in clinical trials, in addition to increasing concerns about both the overuse of and adverse events associated with proton pump inhibitors, raise questions about the precise mechanism and causal link between gastroesophageal reflux and respiratory disease. Our review summarizes key aspiration syndromes with a focus on reflux-mediated aspiration and highlights the need for additional mechanistic studies to find more effective therapies for aspiration syndromes.

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.