Using electroglottographic real-time feedback to control posterior glottal adduction during phonation

Christian Herbst, David Howard, Josef Schlömicher-Thier

The goal of this pilot study was to determine whether the ability to change the degree of posterior glottal adduction during phonation can be acquired more easily with the aid of electroglottographic real-time feedback.
A 37 year old untrained female chorister was asked to participate in the experiment. The initial perceptive evaluation of her singing voice revealed extremely breathy phonation, regardless of pitch and loudness. During the experiment, phonation has been monitored simultaneously with videostroboscopy, electroglottography and audio recording. While phonating, the chorister saw the normalized electroglottographic waveform representing one glottal cycle consecutively changing over time. After an initial “placebo” phase, the actual relevance of the EGG waveform was explained to the chorister. The assignment was to increase the width of the EGG waveform during phonation. Data was collected for sustained notes at a pitch of B3, B4 and G5 respectively.
Laryngeal imaging revealed a considerable posterior glottal chink during habitual phonation. No considerable changes of phonatory quality could be documented for the “placebo” phase. Once the relevance of the EGG waveform has been made clear to the chorister, visual, acoustic and electroglottographic evidence suggests that the subject was able to make intentional changes to the laryngeal configuration during phonation: An increase of the EGG waveform width coincided with the increase of high frequency partials and an increase of posterior glottal adduction. For pitches B3 and B4, a full glottal closure could be achieved. At G5, a reduction of the posterior glottal chink occurred.
The findings of this study suggest that (a) the skill to control the degree of posterior glottal adduction can be acquired, and that (b) electroglottographic real-time feedback can be a crucial element in optimizing the process of skill acquisition, but only if the context and nature of the feedback is explained.

Christian Herbst (herbst@ccrma.stanford.edu)
Tölzer Knabenchor, Munich/Germany
Herbert-von-Karajan-Platz 2/2/2
A-5020 Salzburg
AUSTRIA
+43 662 842074

David Howard (dh@ohm.york.ac.uk)
Department of Electronics, University of York
Heslington
York YO10 5DD
ENGLAND
+44 7766 232928

Josef Schlömicher-Thier (hno-schloemicher@sbg.at)
Austrian Voice Institute
Salzburgerstr. 7
A-5202 Neumarkt a. Wallersee
AUSTRIA
+43 6216 4030