A critical review of electroglottography

The technique of electroglottography is reviewed from the perspective of a laboratory instrument for assessing laryngeal function, a device to assist speech and speaker recognition, and as a potential diagnostic aid in the clinic. A description of the electronic functioning of the electroglottograph (EGG) is provided. Considerable emphasis is given to contemporary research which has focused on laryngeal assessment using the EGG. Methods for validating and aiding the interpretation or reading of the EGG are discussed, including photoglottography, stroboscopy, ultrahigh-speed laryngeal cinematography, and others. The relationship of the EGG to glottal area and glottal volume velocity estimated by inverse filtering is presented. An elementary model of the EGG is described and used to predict characteristic features of the EGG waveform. Clinical data as well as data obtained from subjects with a normal functioning larynx are analyzed. Applications of the EGG to speech processing are outlined, including real-time detection of voicing, voiced and unvoiced speech segments, and silence intervals. The EGG device has potential for assisting speech and speaker recognition systems in certain applications.