Electroglottographic wavegrams: a technique for visualizing vocal fold dynamics noninvasively.
A method for analyzing and displaying electroglottographic (EGG) signals (and their first derivative, DEGG) is introduced: the electroglottographic wavegram ("wavegram" hereafter). To construct a wavegram, the time-varying fundamental frequency is measured and consecutive individual glottal cycles are identified. 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 voice sample in a single image, similar as in sound spectrography. The wavegram provides an intuitive means for quickly assessing vocal fold contact phenomena and their variation over time. Variations in vocal fold contact appear here as a sequence of events rather than single phenomena, taking place over a certain period of time, and changing with pitch, loudness and register. Multiple DEGG peaks are revealed in wavegrams to behave systematically, indicating subtle changes of vocal fold oscillatory regime. As such, EGG wavegrams promise to reveal more information on vocal fold contacting and de-contacting events than previous methods.
Laboratory of Biophysics, Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, tř 17 listopadu 12, 771 46 Olomouc, Czech Republic. herbst@ccrma.stanford.edu
Christian T
CT
Herbst
W Tecumseh S
WT
Fitch
Jan G
JG
Svec
D000465:Algorithms; D004566:Electrodes; D005931:Glottis / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D009146:Music; D010699:Phonation / Q000502:physiology*; D013018:Sound Spectrography / Q000295:instrumentation / Q000379:methods*; D013957:Thyroid Cartilage / Q000502:physiology; D014732:Vibration; D014827:Vocal Cords / Q000502:physiology*; D014831:Voice / Q000502:physiology