it seems unlikely that would have fixed the issue of...

it seems unlikely that would have fixed the issue of bronchodilator pre-cough. That usually is diluted in saline and the saline itself may have loosened up secretions in some, even leading to expectoration/swallowing, therefore altering the sound signature in ways other than muscle relaxation.

In other words, a question is, could the neb alter the sound profile of non-asthmatic LRT disease?

Actually, a sideline in acoustic data gathering that would be useful is cough pre and post "treatment"

But with 20/20 hindsight it is hard to disagree with a small but statistically meaningful blinded study.

Bigger issue may be the problems of noise artefact and voluntary versus involuntary cough. Both should be subject to rigorous troubleshooting.

Might be a nice masters project for UQ biomeds ... is there a difference between the natural cough of an irritated airway or one trying to clear secretion and a voluntarily produced one? Good one for the null hypothesis.

Time critical issues now, but essential to have confidence in I would have thought before the 2nd US paediatric study.