Laryngograph as a measure of vocal fold contact area

The present investigation sought to provide additional information concerning the laryngograph as a means to study vocal fold contact area. Subglottal pressures were sensed simultaneously with the laryngographic signal while the speaker produced a variety of speech tasks. The onset and cessation of the subglottal pressure waveform was studied relative to the laryngographic and speech waveforms. Differences were noted for voiced-voiceless contrasts for bilabial stop consonant production and vocal effort changes during the three vowels studied. Also a high-resistance polymer strip was placed between the vocal folds and gradually removed while simultaneous laryngographic recordings were obtained during sustained productions of the vowel /a/. An increase in the amplitude of the laryngographic waveform upon withdrawal of the polymer strip strongly supported the concept that the laryngographic signal is generated directly by the change in conductance due to alterations in the area of vocal fold contact.