Published online: May 2, 2018
Chronic cough is a cough that lasts for longer than eight weeks. It is a common and debilitating condition that can persist for years despite guideline based medical treatment. Chronic cough affects quality of life, and has numerous side effects including depression, rib fractures, and urinary incontinence. It is associated with irritation in the larynx (voice box) and abnormal voice quality. Even innocuous activities such as talking can trigger coughing episodes leading people to avoid talking and social situations for fear of triggering another coughing episode.
In a recent study published in The Journal of Allergy and Clinical Immunology: In Practice, Vertigan, Kapela, Kearney, and Gibson studied laryngeal function in patients with chronic cough. The aim of the study was to determine whether laryngeal dysfunction was present in patients with chronic cough and whether it was similar to other laryngeal disorders. Participants included patients with chronic cough that persisted despite medical treatment based on current clinical guidelines. These patients were compared to healthy controls and patients with known laryngeal disorders, of muscle tension dysphonia and vocal cord dysfunction.
Patients underwent a range of tests to assess laryngeal function. These tests included questionnaires, voice testing, electronic cough monitoring, and laryngoscopy (a procedure where a small flexible camera is passed through the nasal cavity to view the larynx and vocal folds). The vocal folds were examined during quiet breathing, talking, and when inhaling odors such as perfume.
Patients with chronic cough and vocal cord dysfunction coughed between 10 and 16 times per hour. Patients with chronic cough had abnormal voice symptom scores and increased laryngeal irritation. Ratings of voice quality and objective measures of vocal function were also abnormal. Forty-seven per cent of patients with chronic cough had abnormal closure of the vocal folds during quiet breathing which increased to 67% when inhaling perfume. Up to 75% of patients with chronic cough showed abnormal vocal fold movement while talking. These results were similar to those in patients with muscle tension dysphonia and vocal cord dysfunction.
Laryngeal dysfunction is a significant and frequent problem in chronic cough. There is an overlap in the degree and type of laryngeal dysfunction between chronic cough, muscle tension dysphonia and vocal cord dysfunction. Laryngeal dysfunction may contribute to chronic cough and is a relevant target of treatment. This study suggests that laryngeal function should be considered in patients with chronic cough and can be targeted by speech pathology intervention.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.