The Impact of Functional Laryngoscopy on the Diagnosis of Laryngeal Hypersensitivity Syndromes.

BACKGROUND: Chronic cough and vocal cord dysfunction are manifestations of laryngeal hypersensitivity syndrome. OBJECTIVE: The aim of the study was to determine the clinical utility of functional transnasal laryngoscopy in patients with laryngeal hypersensitivity syndromes. METHODS: This study was a prospective observational cross-sectional study design of 71 participants with laryngeal hypersensitivity syndrome referred for functional transnasal laryngoscopy. Participants had a clinical assessment with a speech pathologist after which a provisional diagnosis of chronic cough, suspected vocal cord dysfunction, suspected muscle tension dysphonia, or a combination was made. A laryngoscopy with provocation was performed and the diagnosis revised after which the provisional and revised diagnoses were compared. RESULTS: The diagnosis changed in 67% of participants after laryngoscopy. Vocal cord dysfunction was diagnosed in an additional 17 cases when not expected clinically but discounted when suspected clinically in 12 participants. Muscle tension dysphonia was diagnosed in an additional 31 cases when not suspected clinically and not confirmed when suspected in 2. CONCLUSION: This study demonstrated that conditions such as muscle tension dysphonia and vocal cord dysfunction cannot be diagnosed based on symptoms alone. In addition to diagnostic accuracy, functional laryngoscopy enhances treatment planning and provides immediate feedback regarding laryngeal movement during respiration and phonation.