The role of sensory dysfunction in the development of voice disorders, chronic cough and paradoxical vocal fold movement.

Sensory function may be important in the pathogenesis of Chronic Cough (CC) and Paradoxical Vocal Fold Movement (PVFM). This paper aims to explore sensory issues related to the pathogenesis, classification, assessment and management of these conditions. Sensory disruption of the vagus nerve can occur through neural plasticity whereby a change occurs in the way a central neuron reacts to an incoming stimulus. Such disruption can be demonstrated through assessment of cough reflex sensitivity and extrathoracic airway hyperresponsiveness both of which may be increased in CC and PVFM. In addition, sensory function may be determined by measuring the laryngeal adductor reflex, however this phenomenon is yet to be explored in CC and PVFM. The similarity in sensory dysfunction between CC and PVFM provides support for a link between the two conditions. There are also similarities in underlying medical conditions and symptom profiles between CC/PVFM and voice disorders such as muscle tension dysphonia. Although coughing and throat clearing may be contributing factors in the development and maintenance of voice disorders, they may occur in response to extrathoracic airway hyperresponsiveness. Dysphonia can occur in CC/PVFM and may improve following behavioural treatment of CC.