Voluntary and reflex cough: similarities and differences.

Cough is defensive airway reflex subjected to a high degree of cortical control. Not surprisingly, all cough motor patterns can be mimicked and reflex cough be inhibited up to complete suppression, at least to a certain extent. Reflex cough differentiates from other airway reflex responses for its characteristic 3-phase motor pattern, and such pattern is maintained when coughing is produced voluntarily. Despite these and some other similarities, voluntary and reflex cough differ in many important respects, suggesting different neural control of the respiratory and non-respiratory musculature implicated in the generation of the cough modalities. This paper focuses the motor features that differentiate voluntary and reflex cough efforts, and highlights the importance of functional assessment of coughing in the diagnostic workup of respiratory and extra-respiratory diseases affecting the production of voluntary and reflex cough.