Impaired cough suppression in chronic refractory cough

Area of Science:

• Neuroscience
• Pulmonology
• Clinical Medicine

Background:

• Functional brain imaging reveals reduced cortical activation for voluntary cough suppression in chronic cough patients.
• The capacity for voluntary cough suppression in chronic cough is poorly understood.

Purpose of the Study:

• To compare voluntary cough suppression ability during capsaicin challenge in chronic refractory cough (CRC) patients versus healthy controls.
• To evaluate the repeatability of the capsaicin challenge test with voluntary cough suppression.

Main Methods:

• Participants underwent inhaled capsaicin challenges with and without attempted cough suppression.
• Threshold capsaicin concentrations for eliciting 1, 2, and 5 coughs were determined.
• Objective 24-hour cough frequency was monitored in CRC patients.

Main Results:

• Healthy controls effectively suppressed capsaicin-evoked coughs, while CRC patients did not.
• Capsaicin thresholds for five coughs with suppression were significantly lower in CRC patients (4.94 µmol/L) compared to controls (261.10 µmol/L).
• The cough suppression test demonstrated high repeatability in both groups and correlated with objective cough frequency.

Conclusions:

• Patients with chronic refractory cough exhibit a diminished ability to voluntarily suppress coughs.
• Impaired cough suppression may play a significant role in the pathophysiology of chronic cough.
• These findings suggest potential new therapeutic targets for chronic cough management.