Inspiratory pressure threshold training for upper airway limitation: a case of bilateral abductor vocal fold paralysis

The Additive Effectiveness of Inspiratory Muscle Training on Glottic Closure and Subjective Voice Outcomes of Patients With Benign Lesion After Hyaluronic Acid Laryngoplasty

OBJECTIVES

For patients with glottic insufficiency disease, injection laryngoplasty is a rapid and efficient management option that complements voice therapy. Some studies have indicated that respiratory muscle training may also show promise in patients with voice disorders. However, the effect of respiratory muscle training in patients with glottic insufficiency was reported to be limited, and whether it provides additional benefit after standard management requires further evaluation. We aimed to investigate the effectiveness of inspiratory muscle training on glottis closure and patient-reported voice quality in glottic insufficiency patients who had been treated with hyaluronic acid injection.

STUDY DESIGN

Retrospective observational study.

METHODS

We included 46 patients with glottic insufficiency who had undergone hyaluronic acid injection. Twenty of them had undergone inspiratory muscle training during three months. We measured patients' changes in glottic status according to the normalized glottal gap area and bowing index, as well as voice quality of life according to the voice handicap index 10 and the voice outcome survey, before and after training.

RESULTS

Patients who underwent inspiratory muscle training had higher odds of experiencing better improvement in all scores. The range of odds ratios ranged from 2.5 to 6.3 for changes in scores, and from 3.8 to 22.2 for changes in score percentages. Of note, the effect of training on percentage changes in the normalized glottal gap area score was significant (P= 0.0127) after adjustment for the duration of vocal disease, body mass index and BMI, and history of gastroesophageal reflux disease.

CONCLUSIONS

Inspiratory muscle training can improve the glottal gap after injection laryngoplasty, and may be applied in clinical practice.

Expiratory Muscle Strength Treatment for Refractory Chronic Cough: A Short-term Single Exercise Program

OBJECTIVES

Patients with chronic cough are some of the most challenging to treat. This preliminary study is the first to examine the effects of a single exercise muscle strength training program to reduce cough severity in patients who failed other treatments.

METHODS

A total of 19 females were included in this study, ranging from age 24 to 80. The maximum phonation time (MPT), laryngeal airway resistance (LAR), maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), Voice Handicap Index-10, (VHI-10) and the Cough Severity Index (CSI) values were obtained pre- and post-treatment. ANOVA two-factor without replication was used to compare values pre- and post-treatment.

RESULTS

MIP (Mean of 62.00 to a mean of 78.53) and MEP (Mean of 90.00 to a mean of 112.16) showed significant increase post-treatment. In addition, LAR (Mean of 73.30 to a mean of 60.67) and CSI (Mean of 19.37 to a mean of 15.00) significantly decreased post-treatment. General changes in pre- and post-treatment values were identified with MPT (Mean of 14.89 to a mean of 16.17) and VHI-10 (Mean of 8.00 to a mean of 6.76). A follow-up questionnaire indicated that the majority of patients felt their cough was better after 4 weeks.

CONCLUSIONS

Muscle strength training provides a tool to aid in the control of cough for patients who are refractory to medical and other behavioral treatments. Improvement in cough may be associated with a reduction in subglottic pressure and increased air flow resulting in lower laryngeal airway resistance.

Inspiratory muscle training for the treatment of dynamic upper airway collapse in racehorses: A preliminary investigation

Exercise-induced upper airway collapse (UAC) probably occurs when the stabilising muscles of the upper airway are unable to withstand the dramatic changes in airflow and pressure that occurs during exercise. In racehorses, the mainstay of treatment is surgical intervention. In human athletes, exercise-induced laryngeal obstruction has been treated successfully with inspiratory muscle training (IMT). The aims of this study were: (1) to assess the feasibility of IMT in racehorses; and (2) describe the exercising endoscopy findings pre- and post-IMT in racehorses diagnosed with dynamic UAC. Horses undergoing IMT wore a mask with an attached threshold-valve to apply an additional load during inspiration, creating a training stimulus with the purpose of increasing upper airway muscle strength. Each horse underwent IMT once daily, while standing in the stable, 5-6 days/week for 10 weeks. Endoscopy recordings were analysed in a blinded manner using an objective grading scheme and subjective pairwise analysis. Seventeen horses successfully completed the IMT protocol, with full information available for 10 horses. Objective grading analysis showed a lower grade of vocal fold collapse (6/9 horses), palatal instability (7/10 horses) and intermittent dorsal displacement of the soft palate (5/7 horses) post-IMT. Pairwise subjective analysis suggested better overall airway function post-IMT in 3/10 horses. The main limitations of this preliminary investigation were the low number of horses examined and lack of a control population. Further research is required to investigate the effects of IMT on upper airway muscle strength and to evaluate its efficacy for prevention and treatment of UAC.

A Conceptual Framework for Understanding Speaking Dyspnea

Purpose A conceptual framework is proposed to better understand the experience of people who have dyspnea (breathing discomfort) when speaking: its nature, its physiological mechanisms, and its impacts on their lives. Method The components of the framework are presented in their natural order. They are a Speaking Domain (Speaking Activities and Speaking Variables), a Physiological Domain (Speech Breathing Variables and Physiological Mechanisms), a Perceptual Domain (Dyspnea), a Symptom Impact Domain (Emotional Responses, Immediate Behavioral Responses, and Long-Term Behavioral Response), and a Life Impact Domain (Short-Term Impacts and Long-Term Impacts). Results We discuss literature that most directly supports these components and includes findings from healthy people and those with disorders in whom speaking dyspnea was either evoked or measured. Caveats are noted where information is limited and further study is needed. A case example is provided to illustrate how to apply the framework. Conclusions This framework provides a broader view of the elements that contribute to the experience of speaking dyspnea. It is meant to guide researchers, clinicians, instructors, caregivers, and those for whom speaking dyspnea is a daily or even a life-long challenge.

Struggling to Breathe: Inspiratory Muscle Training in Adolescent Athletes

OBJECTIVE

Dyspnea is a primary characteristic of exercise-induced laryngeal obstruction and prevents individuals from inhaling and exhaling without effort. This single subject research study investigated the effects of inspiratory muscle training (IMT) on exercise-induced symptoms characteristic of exercise-induced laryngeal obstruction in adolescent athletes.

METHODS

Five weeks of IMT was provided to five adolescent athletes, four females and one male, aged 10 to 16. Variables that were measured prior to, during, and after completion of IMT program included maximum phonation time, maximum perceived breathlessness, duration of running, and quality of life regarding dyspnea.

RESULTS

Results showed a reduction in maximum perceived breathlessness as well as a significant increase in maximum phonation time across participants. The majority of participants rated their quality of life regarding dyspnea as significant improved after IMT.

CONCLUSIONS

These findings contribute to the increasing body of literature investigating the use of alternative therapy strategies for treatment of symptoms of exercise-induced laryngeal obstruction in adolescent athletes.

Exercise-induced laryngeal obstruction in athletes treated with inspiratory muscle training

Background

Exercise-induced laryngeal obstruction (EILO) is common in athletes and presents with dyspnoea, chest tightness, inspiratory stridor and sometimes panic reactions. The evidence for conservative treatment is weak, but case reports suggest effects from inspiratory muscle training (IMT). We aimed to explore effects from IMT used in athletes with EILO.

Method

Twenty-eight athletes, mean age 16.4 years, diagnosed with EILO at our clinic, participated in a 6-week treatment programme, using a resistive flow-dependent IMT device (Respifit S). Four athletes competed at international level, 13 at national and 11 at regional levels. Video-recorded continuous transnasal flexible laryngoscopy was performed from rest to peak exercise (continuous laryngoscopy exercise (CLE) test) and scored before and 2–4 weeks after the training period. Ergospirometric variables were obtained from this CLE set-up. Lung function was measured according to guidelines. Symptom scores and demographic variables were obtained from a questionnaire.

Results

After the treatment period, symptoms had decreased in 22/28 (79%) participants. Mean overall CLE score had improved after treatment (p<0.001), with the scores becoming normal in five athletes but worse in two. Most of the improvement was explained by changes at the glottic laryngeal level (p=0.009). Ergospirometric variables revealed significantly higher peak minute ventilation explained by higher tidal volumes and were otherwise unchanged.

Conclusion

This explorative study underlines the heterogeneous treatment response of EILO and suggests that IMT may become an efficient conservative treatment tool in subgroups, possibly contributing to better control of the vocal folds. The signals from this study should be tested in future controlled interventional studies.

The effects of inspiratory muscle training based on the perceptions of patients with advanced lung disease: a qualitative study

BACKGROUND

Advanced lung disease is a chronic non-neoplastic disease that compromises activities of daily living. Treatment includes pulmonary rehabilitation and inspiratory muscle training. Studies have shown the effectiveness of inspiratory muscle training in lung disease patients, but literature is scarce on the patients' perceptions about this topic.

OBJECTIVE

To explore the perceptions of patients with advanced lung disease about inspiratory muscle training.

METHODS

Qualitative study. Interviews were conducted using a semi-structured questionnaire regarding topics on the participation of patients in inspiratory muscle training and on daily activities performed before and after training. Interviews were transcribed and analyzed according to thematic content analysis.

RESULTS

Ten patients (eight women and 2 men, ranging in age from 27 to 89 years) with inspiratory muscle weakness (maximal inspiratory pressure=44±13.9cmH₂O) were included. Five patients were diagnosed with Chronic Obstructive Pulmonary Disease, two with bronchiectasis and three with pulmonary fibrosis. All patients completed at least 80% of the total training sessions. The reports were grouped into four thematic categories: (1) impact of inspiratory muscle training on breathlessness (e.g., "I wasn't feeling as tired as I previously felt."); (2) change in daily activities (e.g., "I needed to go to the supermarket, I felt less tired doing it."); (3) improved mobility (e.g., "I could not stand for long periods […] walking, for example […] Now I stand more, I have more capability."); and (4) increased communication (e.g., "More power, right? Even in speaking […] When I could, I felt my voice coming out better.").

CONCLUSION

There were improvements in breathlessness, daily activities, mobility, and communication, which positively affected the psychological and social aspects of the patients.

Exercise inducible laryngeal obstruction: diagnostics and management

Obstruction of the central airways is an important cause of exercise-induced inspiratory symptoms (EIIS) in young and otherwise healthy individuals. This is a large, heterogeneous and vastly understudied group of patients. The symptoms are too often confused with those of asthma. Laryngoscopy performed as symptoms evolve during increasing exercise is pivotal, since the larynx plays an important role in symptomatology for the majority. Abnormalities vary between patients, and laryngoscopic findings are important for correct treatment and handling. The simplistic view that all EIIS is due to vocal cord dysfunction [VCD] still hampers science and patient management. Causal mechanisms are poorly understood. Most treatment options are based on weak evidence, but most patients seem to benefit from individualised information and guidance. The place of surgery has not been settled, but supraglottoplasty may cure well-defined severe cases. A systematic clinical approach, more and better research and randomised controlled treatment trials are of utmost importance in this field of respiratory medicine.

Spontaneous Laryngeal Reinnervation after Recurrent Laryngeal or Vagus Nerve Injury

Objectives:

The status of innervation in patients with laryngeal paralysis is somewhat controversial. Electromyographic activity has been frequently documented in the laryngeal muscles of patients with laryngeal paralysis, and animal experiments report a strong propensity for reinnervation after laryngeal nerve injury. However, a study of intraoperative electromyography performed in patients during reinnervation surgery failed to document activity with stimulation of the recurrent laryngeal nerve (RLN). Noting the long-observed differences in the symptoms of patients with vagus nerve injury and those with RLN injury, I hypothesized that reinnervation is influenced by the site of nerve injury.

Methods:

Cats were sacrificed at various intervals after resection of 1 cm of either the RLN or the vagus nerve, without any attempt to repair the nerve.

Results:

Four months after RLN resection, distal nerve biopsy revealed unmyelinated axons scattered through fibrous tissue. By 6 months, myelinated axons were organized, and electromyographic and histologic examination showed preferential reinnervation of the thyroarytenoid muscle. After vagotomy, the RLN was fibrotic and no axons were present. Both the thyroarytenoid and posterior cricoarytenoid muscles were fibrotic and had no electromyographic activity.

Conclusions:

The results confirm the strong propensity for laryngeal reinnervation after RLN injury, but not after vagus nerve injury. Preferential reinnervation of adductor muscles may account for a medial position of the paralyzed vocal fold.

Larynx during exercise: the unexplored bottleneck of the airways

Exercise-induced shortness of breath is not uncommon in otherwise healthy young people. Based on the presenting symptoms alone, it is challenging to distinguish exercise-induced asthma (EIA) from exercise-induced obstruction of central airways, sometimes leading to diagnostic errors and inadequate treatment. Central airway obstruction usually presents with exercise-induced inspiratory symptoms (EIIS) during ongoing exercise. EIIS tends to peak towards the end of an exercise session or immediately after its completion, contradicting symptoms of EIA typically peaking 3–15 min after the exercise has stopped. EIIS is usually associated with some form of laryngeal obstruction. Transnasal flexible laryngoscopy performed continuously throughout an incremental exercise test from rest to exhaustion or to intolerable symptoms is usually diagnostic, and also provides information that is important for further handling and treatment. Reflecting the complex anatomy and functional features of the larynx, exercise-induced laryngeal obstruction (EILO) appears to be a heterogeneous condition. Contradicting previous beliefs, recent literature suggests that laryngeal adduction in a majority of cases starts in supraglottic structures and that vocal cord adduction (VCD) most often occurs as a secondary phenomenon. However, EILO is poorly understood and more and better research is needed to unravel causal mechanisms. The evidence base for treatment of EILO is weak. Speech therapy, psychotherapy, biofeedback, muscle training, anticholinergic aerosols have all been applied, as has laser supraglottoplasty. Randomized controlled trials with well-defined and verifiable inclusion and success criteria are required to establish evidence-based treatment schemes.

Acute and chronic responses of the upper airway to inspiratory loading in healthy awake humans: an MRI study

We assessed upper airway responses to acute and chronic inspiratory loading. In Experiment I, 11 healthy subjects underwent T(2)-weighted magnetic resonance imaging (MRI) of upper airway dilator muscles (genioglossus and geniohyoid) before and up to 10 min after a single bout of pressure threshold inspiratory muscle training (IMT) at 60% maximal inspiratory mouth pressure (MIP). T(2) values for genioglossus and geniohyoid were increased versus control (p<0.001), suggesting that these airway dilator muscles are activated in response to acute IMT. In Experiment II, nine subjects underwent 2D-Flash sequence MRI of the upper airway during quiet breathing and while performing single inspirations against resistive loads (10%, 30% and 50% MIP); this procedure was repeated after 6 weeks of IMT. Lateral narrowing of the upper airway occurred at all loads, whilst anteroposterior narrowing occurred at the level of the laryngopharynx at loads > or =30% MIP. Changes in upper airway morphology and narrowing after IMT were undetectable using MRI.

Inspiratory Muscle Training in Exercise-Induced Paradoxical Vocal Fold Motion

The purpose of the study was to determine if inspiratory muscle training (IMT) would result in increased inspiratory muscle strength, reduced perception of exertional dyspnea, and improved measures of maximal exercise effort in an athlete with exercise-induced paradoxical vocal fold motion (PVFM). The participant, an 18-year-old woman, had a 2-year history of acute dyspnea with exertion during soccer games. Spirometry, transnasal flexible laryngoscopy, and patient history supported a PVFM diagnosis. The ABAB within-subject withdrawal design study comprised IMT treatment and withdrawal phases, each lasting 5 weeks. The participant trained 5 days per week, completing five sets of 12 breaths at 75% maximum inspiratory pressure (MIP) per session. Data consisted of MIP, exertional dyspnea ratings, and maximal exercise measures. IMT resulted in increased MIP and decreased dyspnea ratings across both treatment phases. No change in MIP or dyspnea ratings occurred in response to treatment withdrawal. The maximal exercise test revealed minimal changes across phases. At end of the study, the participant reported experiencing no PVFM symptoms when performing the outcome measurement tasks and when playing soccer. Transnasal flexible laryngoscopy, after strenuous exercise and during rapid breathing and phonation tasks, revealed normal laryngeal findings. The findings suggest that IMT may be a promising treatment approach for athletes with exercise-induced PVFM.

Laryngeal Structure and Function in the Pediatric Larynx

This article presents an overview of the normal anatomy and physiology of the pediatric larynx, followed by some examples of pediatric voice disorders that were chosen to exemplify the alterations to the laryngeal anatomy and the subsequent modifications to laryngeal function. Vocal fold nodules are primarily reviewed due to their high incidence in the pediatric population. Three other disorders, including laryngeal hyperfunction, unilateral vocal fold paralysis, and bilateral abductor vocal fold paralysis, are discussed because of their more common occurrence and the uniqueness of their etiology and intervention, particularly for the case of bilateral abductor vocal fold paralysis.