Abnormal vocal cord movement in asthma: Impact on the flow volume curve

Traditionally the “gold standard” for detecting abnormal vocal cord movement has been laryngoscopy. Novel dynamic 320-slice CT larynx has made it possible to quantify vocal cord movement non-invasively during inspiration and expiration. While spirometry has been useful in observing upper airway obstruction, little is known of its utility in identifying patients with abnormal vocal cord movement. Aims: To identify changes in the flow volume curve in patients with abnormal vocal cord movement (AVCM). Methods: Two groups comprising controls and asthmatics were recruited. Vocal cord abnormality was evaluated using 320-slice CT larynx. All patients had spirometry immediately prior to CT and relevant parameters were compared. Results: AVCM was not found in healthy control subjects. However, it was present in 11/23 asthmatics (50%). Discussion: While there was a significant difference in FEV1 between control and the two asthma groups, it identified obstruction alone. The only other discerning spirometric parameter was FIF50%/FEF50% which was significantly different between the control group and those with AVCM. Conclusion: Spirometric parameters appear to be poor discriminators for detecting AVCM. It may be that more sensitive lung function measures, such a resistance measured with body plethysmograph or oscillometer will be required to further discriminate between obstruction of the upper and/or lower airways.