FIGURE 1.

The grading system illustrated by photographic images of the larynx showing the different grades of laryngeal obstruction at the glottic and supraglottic levels. ^#: the scores at each level (glottic (A and C) and supraglottic (B and D)) were assessed at moderate (A, B) (when the subject started to run) and at maximal (C, D) (just before the subject stopped running on the treadmill) effort; all four levels (A–D) were noted together with a sum score (E) for each test/subject. Reproduced from [11] with permission from the publisher.