Electroglottographic wavegram

[1] The wavegram, invented by Christian T. Herbst, provides an intuitive means for quickly assessing vocal fold contact phenomena and their variation over time.

Vocal fold closings and openings appear here as a sequence of events rather than single incidents, taking place over a certain period of time, and changing with pitch, loudness and register.

Wavegrams document systematic phenomena[clarification needed], indicating subtle changes of the vocal fold oscillatory regime.

Each cycle is locally normalized in duration and amplitude, the signal values are encoded by color intensity and the cycles are concatenated to display the entire phonation in a single image, much as in sound spectrography.

The idea of wavegrams can be extended to displaying other data, such as acoustic signals or high-speed video endoscopic recordings of the vibrating vocal folds.