Diagnosing exercise induced laryngeal obstruction: The influence of air temperature and humidity on exercise induced laryngeal obstruction (EILO)

Exercise induced laryngeal obstruction (EILO) is limiting cause of exertional
dyspnoea, and most common in adolescent athletes. EILO is an inappropriate
closure of the larynx during strenuous physical activity with no obvious
laryngeal pathology at rest. Despite the high prevalence of EILO,
pathophysiology and physiological changes preluding EILO are still poorly
understood. It is suggested that environmental factors such as cold air play a
role in the pathogenesis of EILO (1). EILO can be diagnosed by continuous
laryngoscopy during exercise (CLE), during which patients perform an
incremental exercise test until symptoms occur while the larynx is continuously
visualized. We hypothesize that performing CLE tests in a cold, dry air leads
to a higher number of positive tests than performing CLE tests at room
temperature. Furthermore, we aim to gain a better understanding of the
pathophysiological changes leading up to EILO by collecting detailed
physiological data during CLE tests. A better understanding of factors and
circumstances triggering and preluding EILO can hopefully guide towards
tailored and effective therapeutic options.

To investigate the influence of air temperature and humidity on the occurrence
of EILO. A better understanding of the pathophysiologic principles causing EILO
could lead to increased sensitivity of CLE testing. New insights in the causes
of EILO can also lead towards new therapeutic strategies as there is no
evidence based therapy regarding EILO yet.

This study has a prospective, randomized, cross-over design. Subjects suspected
to have EILO who are planned for a CLE test will be asked to perform one extra
CLE test. One test will take place at room temperature, and one in cold, dry
air (5- 10 dgr C) by using a climate chamber. Patients will be randomized into
two groups. One group first performs the test at room temperature, and the
other group first performs the test in cold, dry air. During the CLE test there
will be extensive monitoring of physiological responses to exercise. Patients
will also be asked to fill in a questionnaire about their symptoms and factors
eliciting dyspnoea.

-Cold, dry air by using a climate chamber (5-10 dgrC)

The burden of participating in this study involves one extra CLE test compared
to standard care. The test takes about one hour and risks are minimal. Patients
will be asked to fill in a questionnaire about their symptoms and perceived
influence of environmental factors on their symptoms. The extra measurements by
Hexoskin and EMG involve no additional risk, besides a small change of an
allergic reaction to EMG stickers. Therefore latex-free stickers are used).
Both Hexoskin and EMG are only used for data collection and are not acted upon
yet.
A benefit of participating is the possible higher chance to receive a positive
test result. This age group is most suited, since EILO prevalence tends to be
highest amongst adolescents. Risks associated with this study are deemed to be
low