When looking at the videos from the endoscopy study in 2007 certain patterns are seen in the laryngeal gestures AND the waveform within each mode. A still image for each of the modes was produced from the videos.
The Laryngeal gestures and the Laryngograph waveforms are more to be seen as patterns of progression from mode to mode, rather than absolutes. The larynx, the laryngeal gestures and the waveforms often differ from singer to singer, some singers have really weird waveforms, but still the patterns often show similar features. The progressive change in the patterns can be used as a guideline on how to identify the modes for an individual singer.
On the stills from the videos and on the video itself both the laryngeal gestures and the waveform are seen.
Notice in Edge the opening of the larynx is even more narrowed, and the cuneiforms are rolled in even more than in Overdrive. This makes it hard to see the vocal folds. The narrowing creates an even flatter angle between the arytenoids and the aryepiglottic fold and also an even more acute angle between the aryepiglottic fold and epiglottis. The piriform fossae and area between the back wall (posterior pharyngeal wall) and the larynx becomes very small and is often closed off altogether. The larynx is raised to a higher position (you can see that it gets closer to the camera).
Also notice the Edge laryngograph waveform shows a steep onset and a quite long closure of the vocal folds with a gradual roll off. The steep onset indicates that the vocal folds are coming together very rapidly and stay together for longer, so they are closed much longer than they are open. This corresponds nicely with the loud volume often used in Edge.
This information comes from a study Visual Vocal Mode Test Study on stills, with the title ‘Laryngeal gestures and Laryngograph data associated with the four vocal modes as described in the Complete Vocal Technique method of singing teaching’. This study was presented by Cathrine Sadolin and Julian McGlashan at BVA ‘Choice for voice’ conference in London, England, 2010.