Cough reflex sensitivity improves with speech language pathology management of refractory chronic cough

The aim of this study was to investigate subjective and objective measures of cough before, during and after speech language pathology treatment for refractory chronic cough and the mechanism underlying the improvement.Adults with chronic cough (n = 17) were assessed before, during and after speech language pathology intervention for refractory chronic cough. The primary outcome measures were capsaicin cough reflex sensitivity, automated cough frequency detection and cough-related quality of life.Following treatment there was a significant improvement in cough related quality of life (Median (IQR) at baseline: 13.5 (6.3) vs. post treatment: 16.9 (4.9), p = 0.002), objective cough frequency (Mean ± SD at baseline: 72.5 ± 55.8 vs. post treatment: 25 ± 27.9 coughs/hr, p = 0.009), and cough reflex sensitivity (Mean ± SD log C5 at baseline: 0.88 ± 0.48 vs. post treatment: 1.65 ± 0.88, p < 0.0001).This is the first study to show that speech language pathology management is an effective intervention for refractory chronic cough and that the mechanism behind the improvement is due to reduced laryngeal irritation which results in decreased cough sensitivity, decreased urge to cough and an increased cough threshold. Speech language pathology may be a useful and sustained treatment for refractory chronic cough.Australian New Zealand Clinical Trials Register, ACTRN12608000284369.Chronic cough that persists despite medical treatment (termed refractory cough) is a difficult problem frequently associated with increased cough reflex sensitivity [1-3]. Management using speech language pathology is effective for both refractory cough and its associated voice disorder [4,5] but the mechanism behind the symptom improvement has yet to be determined. Cough reflex hypersensitivity plays an important role in chronic cough [6,7], and it was hypothesised that speech language pathology would either increase the threshold for cough or reduce cough sensitivity [4]. These effects could be achiev