Evaluating the Feasibility and Reliability of Using Handheld Nebulizers to Conduct Cough Sensitivity Testing With Citric Acid

Objective cough reflex sensitivity testing is typically restricted to specialized research laboratories due to reliance on expensive dosimeter-controlled aerosol delivery systems. This study evaluates the feasibility and reliability of a low-cost alternative method using a handheld nebulizer for citric acid cough challenge testing. Healthy adult participants will complete cough reflex sensitivity testing using both a standard dosimeter-controlled nebulizer system (Cosmed QuarkSpiro) and a handheld nebulizer (DeVilbiss 45). The study will compare cough threshold outcomes between methods to determine whether handheld nebulizer-based testing produces comparable and reproducible measurements.

Inclusion Criteria: * Healthy adults at least 18 years of age * Consent to audio/video recording of the research sessions for research purposes * Spirometry testing results obtained by study team on same day of first testing session with FEV1/FVC ratio and FEV1 percent predicted values of at least 0.70 Exclusion Criteria: * Pregnant or trying to become pregnant (if capable of becoming pregnant- a urine pregnancy test will be provided onsite and a negative result must be obtained prior to the first testing session) * Smoking of any substance in the last six months * Diagnosed or suspected pulmonary disease (e.g., asthma, COPD) * History of chronic cough * History of head or neck cancer * History of neurological disease (e.g., cerebrovascular accident) * History of dysphagia (swallowing difficulty) * Current complaint of a voice problem * Current upper respiratory infection