Electroglottagraphy

An instrument that provides information about glottal states, Electroglottagraphy (EGG) measures the degree of vocal fold contact as a function of the relative conductance or impedance between two small electrodes placed on either side of the larynx. When the glottis is closed, and a small electric current is conducted across the folds (from one electrode to the other), the EGG signal peaks. As the folds separate, the signal decreases because of the impedance created by the open glottis. Hence, the electroglottograph indicates the amount of vocal fold contact, but it does not tell us anything about the width or shape of vocal fold opening.

Links

 * Utrecht Lexicon of Linguistics
 * EEG signal
 * Audiodemonstrations