Materials and Methods
Thirty flexible fibreoptic nasendoscopy videos of laryngeal movement
were captured in a laryngology clinic. These ranged from normal vocal
cord movement to complete laryngeal paralysis (nine normal cases, four
palsies, three nodules, two cases each of cysts, functional dysphonia,
and inflammation, one case each of Reinke’s oedema, presbyphonia, polyp,
hypo pharynx lesion, supraglottic lesion, crescentic defect of vocal
cord, weakness and slower right vocal cord movement). The videos were
pre-processed to reduce the effect of the honeycomb artefact caused by
the fibreoptic endoscopes5. Six consultant head and
neck surgeons (JM, RT, OH, MB, SR, KM) were asked to subjectively assess
vocal cord motion by visual inspection of the laryngeal videos and
individually rate the movement of the left and right vocal cords
independently on a scale of 0 to 4, see table 1. There was no clinical
history or sound associated with the videos. This process was repeated
with the same videos, in a different order, on three separate occasions
with a minimum of two weeks between each rating session. Each consultant
rated the videos three times giving a total of 180 individual ratings (2
[R & L cord] x 30 x 3 = 180 ) per consultant and 1080 (180 x 6
consultants) ratings in total. The consultants were blinded to their
previous and other raters’ scores. Ethical approval was not required for
this study.