Abstract
Background
Paradoxical vocal cord dysfunction (pVCD) is diagnosed in children using nasendoscopy. Nasendoscopy, however, is invasive and difficult for children to tolerate. An alternative, non-invasive, technique is required to improve the diagnosis of this under-recognised condition.
Aim
The aim of this study was to determine whether respiratory sound analysis (RSA) can be used to identify pVCD in children with nasendoscopically proven pVCD.
Methods
43 children (11 with suspected pVCD, 11 with thoracic dysfunctional breathing (T-DB) and 21 with no respiratory problems) aged 8-16 years performed a treadmill based exercise test, to provoke symptoms of pVCD, whilst undergoing RSA using the PulmoTrackTM system. Children with suspected pVCD underwent pre and post exercise test nasendoscopy to confirm the presence of the condition.
Results
RSA was well tolerated by the children with 100% of recordings completed. Using audio and visual data, abnormal respiratory sounds were identified in each of the three participant groups. The proportion of children with confirmed pVCD who were positive for abnormal sounds was twice that of either those with T-DB or healthy controls (67% v 29% and 24%). The PulmoTrack automated sound analysis software did not, however, reflect these differences with no apparent difference seen between groups for abnormal sounds on either inspiration, expiration or as a combined total of inspiration and expiration.
Conclusion
Data from this study supports the possibility of using respiratory sound analysis as a non-invasive means of diagnosing pVCD. However, objective analysis of abnormal sounds is not currently possible using the technology available.
- © 2014 ERS