Control of the larynx in patients with obstructive and restrictive pulmonary impairment.

To study changes in glottic movements associated with pulmonary functional abnormalities, we measured changes in glottic resistance (Rgl) during quiet tidal breathing in normal subjects (N), patients with chronic obstructive pulmonary disease (COPD) and patients with idiopathic pulmonary fibrosis (IPF). Changes in Rgl were measured with a non-invasive method using low frequency sound. Changes in Rgl were tightly coupled to changes in tidal volume and were reproducible in all subjects. Rgl was higher during expiration than during inspiration in N and COPD. COPD showed greater changes in Rgl between inspiration and expiration than did N. However, Rgl did not differ between inspiration and expiration in three of six IPF, and was lower during expiration than during inspiration in two of six IPF. We suggest that glottic movements during quiet tidal breathing change in association with the functional abnormalities of pulmonary diseases.