Glottal-area time function and subglottal-pressure variation.

High‐speed photography of the vibrating laryngeal structures was done on one female subject simultaneously with a direct recording of the vibratory air‐pressure variation in the trachea. The glottal dimensions and pressure data were obtained from this film using a semiautomated digital‐reduction technique. It was observed that the peaks of the subglottal‐pressure waves correspond with the dips in the glottal‐area waves, and also that the fundamental periodicity of the subglottal‐pressure wave represents the glottal‐area periodicity with good accuracy. Relations between the glottal‐area function and the glottal‐width function were considered. It is suggested that the glottal‐width function may be considered to be an approximate estimate of the glottal‐area function if the vibrating structure in the larynx is unaffected by pathology.