Paradoxical vocal cord motion: a review focused on multiple system atrophy.

OBJECTIVE: Paradoxical vocal cord motion (PVCM) is a well recognized respiratory condition in which active adduction of the vocal cords during inspiration causes functional airway obstruction. It is considered that laryngeal reflex acceleration underlies the generation of nonorganic PVCM. In various situations producing PVCM, multiple system atrophy (MSA) is a representative neurological disease causing nocturnal laryngeal stridor attributed to PVCM. The purpose of this review is to identify the underlying mechanisms associated with nonorganic and MSA-related PVCM. The following issues are addressed in this review: (1) the pathophysiology of nonorganic and MSA-related PVCM, (2) the relationships between PVCM and airway reflexes, and (3) the treatment for MSA-related PVCM.

METHODS: Review.

RESULTS AND CONCLUSIONS: An abnormality of the laryngeal output-feedback control underlies nonorganic PVCM, which is usually triggered by an excessive response to external and internal airway stimuli. Similarly, several clinical and experimental evidence suggest that MSA-related PVCM is attributed to the airway reflex as well as to paradoxical central outputs resulting from the MSA-induced damage to the pontomedullary respiratory center. Application of continuous positive airway pressure (CPAP), which suppresses the reflexive inspiratory activation of adductors, is recommended as the treatment for MSA-related PVCM.