Comparison of glottal area changes as measured from ultrahigh-speed photographs and photoelectric glottographs.

To determine the relationship of information on glottal area function provided by deviations sensed by the photoelectric glottograph to that derived from a frame-by-frame analysis of ultrahigh-speed photographic film, simultaneous photographic and glottographic recordings were obtained from five subjects. From the investigation, the following results were obtained: (1) the measurements of the light deviations sensed by the photoelectric glottograph during laryngeal vibrations produced curves that approximated those developed from photographic film frame-by-frame measurements of the visual image in vocal fry, modal, and falsetto voice registers, and (2) the Fourier coefficients of the compared data indicated that there was no significant difference between the curves.