What is cough and what should be measured?

Area of Science:

• Respiratory Physiology
• Neuroscience

Background:

• Cough is typically a three-phase event, but often simplified clinically to expiratory efforts.
• Cough can manifest as a single event or a 'cough epoch' comprising multiple expiratory efforts.
• Distinguishing between single coughs and cough epochs is vital due to differing neural mechanisms and clinical implications.

Purpose of the Study:

• To delineate the assessment methods for cough.
• To highlight the importance of understanding cough mechanics for clinical and research purposes.

Main Methods:

• Review of cough assessment techniques.
• Discussion of methods including patient scores, automated counters, expiratory electromyography (EMG), respiratory pressures, airflows, and lung volume changes.

Main Results:

• Clinical assessment often simplifies cough to expiratory efforts.
• Automated counters and patient scores capture only limited aspects of cough complexity.
• Comprehensive studies require measurement of expiratory EMGs, respiratory pressures, airflows, and lung volumes.

Conclusions:

• A clear definition of 'cough intensity' is needed, specifying the measured parameters.
• Accurate cough assessment requires considering its multi-faceted nature, including single events versus epochs.
• Further research into the distinct neural mechanisms of cough reflexes and expiration reflexes (ERs) is warranted.