Objective assessment of cough.

Cough is a primitive reflex typically consisting of an initiating deep inspiration, glottal closure, and an explosive expiration accompanied by a sound. The flow characteristics of cough have been shown to differ between different pulmonary diseases. Cough sounds are generated at the larynx and in the lungs. Modern analysing techniques have also been applied in cough sound studies, and differences in cough sound duration and spectra have been found in pulmonary diseases with different bronchopulmonary pathophysiology. Since the objective assessment of cough is clinically important, automatic cough detectors and counters have been constructed, e.g. to assess the efficacy of antitussive drugs. Also, ambulatory methods for assessment of cough have been reported. This review includes a brief history of cough research and present methods available for objective assessment of cough.