Laryngeal Dysfunction in Cough Hypersensitivity Syndrome: A Cross-Sectional Observational Study.

BACKGROUND: Chronic refractory cough (CRC), a phenotype of cough hypersensitivity syndrome (CHS), is a disabling problem. Laryngeal dysfunction may be important in CRC and CHS because laryngeal symptoms are common; however, the role of laryngeal dysfunction in CHS has not been systematically examined. OBJECTIVE: To determine the nature of laryngeal dysfunction in patients with CRC and compare with the related laryngeal conditions of vocal cord dysfunction (VCD) and muscle tension dysphonia (MTD). METHODS: A cross-sectional analytic design was used. We recruited 69 participants including healthy controls and patients with CRC, VCD, and MTD who were referred for behavioral speech interventions. Participants underwent a comprehensive assessment of laryngeal function during breathing, phonation, and swallowing. RESULTS: Cough frequency was high in patients with CRC (10.2 coughs/h) and VCD (16.5 coughs/h), but low in healthy controls (1.5 coughs/h) (P < .001). Patients with CRC, VCD, and MTD had impaired voice-related quality of life (vs controls, P < .05) and laryngeal hypersensitivity (vs controls, P < .05). Most voice assessment measures (3 out of 4) were significantly impaired in the CRC group compared with controls and were similar to the VCD and MTD groups. Paradoxical vocal fold movement during respiration was present in 47% of the patients with CRC at rest and in 67% after odor challenge. Mediolateral laryngeal constriction during phonation was present in 45% of the participants with CRC, 93% of the participants with VCD (P < .001 vs CC), and 64% of the participants with MTD. CONCLUSIONS: Laryngeal dysfunction is common in CRC and CHS and may contribute to CHS mechanisms. Assessment and treatment of laryngeal dysfunction using speech pathology interventions are likely to be beneficial in CHS.