Published online: September 30, 2020
Severe asthma is diagnosed when asthma symptoms persist despite high-dose treatment and optimal management. Severe asthma poses a significant disease burden for patients and contributes to substantial health care costs. Vocal cord dysfunction is an important comorbidity in severe asthma. Vocal cord dysfunction occurs when the vocal folds close suddenly and involuntarily during breathing and leads to shortness of breath, noisy breathing, and cough. Vocal cord dysfunction is often confused with asthma. Additionally, patients with asthma frequently experience voice symptoms. Laryngeal dysfunction in severe asthma is poorly characterized. The aim of this study was to determine the nature of laryngeal function in patients with severe asthma and compare this with other known laryngeal disorders, including vocal cord dysfunction and muscle tension dysphonia.
In a study published by The Journal of Allergy and Clinical Immunology: In Practice, Vertigan and colleagues examined laryngeal function in 4 groups of patients: severe asthma, vocal cord dysfunction, muscle tension dysphonia, and healthy controls. Participants engaged in a range of tests including functional transnasal laryngoscopy, validated patient symptom ratings, and voice testing. Ten patients with severe asthma were randomly selected for a pilot of speech pathology intervention.
Participants with severe asthma had laryngeal hypersensitivity, increased cough, and reduced voice quality of life. The majority of participants with severe asthma had laryngeal dysfunction (88%) which affected breathing, voice, or both. Abnormal vocal fold movement during breathing was present and similar between patients with asthma and vocal cord dysfunction. Abnormal tension in the muscles of the vocal folds and larynx (voice box) were also present during speech. This result shows that muscle tension patterns contribute to abnormal voice quality in patients with asthma. In the 10 participants who had speech pathology intervention, the average Asthma Control Questionnaire score improved by 0.5, and all participants demonstrated improvement in at least 1 symptom. Despite this, lung function did not change.
Asthma has traditionally been considered a lower airway abnormality. The high prevalence of laryngeal dysfunction in severe asthma suggests a strong association that can manifest itself as muscle tension dysphonia or vocal cord dysfunction. Preliminary evidence shows that laryngeal dysfunction responds favourably to speech pathology intervention leading to improved asthma control scores. Laryngeal dysfunction requires assessment and treatment to minimize its impact on asthma symptoms and to enable targeted treatment.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.