The role of altered upper airway sensitivity in respiratory disease: evidence from human studies

The upper airway is intricately involved in airway protection guarding against aspiration of noxious solid and liquid materials. The larynx and pharynx are exquisitely sensitive to mechanical and chemical stimuli which trigger protective reflexes resulting in a number of behavioural elements designed to prevent aspiration including coughing, swallowing, vocal cord adduction and suppression of respiration. Depression or exaggeration of these reflexes result in clinical problems and recent improvement in methods designed to assess laryngopharyngeal sensation in humans has added greatly to our knowledge of these airway reflexes in both health and disease.