ASA 125th Meeting Ottawa 1993 May

5aSP4. Endoscopy, stroboscopy, and transillumination in speech research.

Anders Lofqvist

Kiyoshi Oshima

Haskins Labs., 270 Crown St., New Haven, CT 06511-6695

This tape demonstrates the application of endoscopy, stroboscopy, and transillumination to the study of laryngeal function in speech. Stroboscopy involves intermittent illumination of the vibrating glottis using short flashes of light with a frequency of slightly less than that of the glottal vibrations. Thus it has the effect of apparently slowing down the vibrations so that they can be visualized and measured. It has to be remembered, however, that one vibratory cycle recorded using stroboscopy is the composite of several actual glottal cycles. Recordings can be made using either a rigid endoscope or a flexible fiberscope; the latter allows analysis of running speech. Images are recorded on video tape for subsequent processing. Transillumination records the amount of light passing through the glottis and thus variations in the size of the glottal opening. The light is provided by a fiberscope and a transducer is placed on the neck. Transillumination is particularly useful for recording glottal abduction and adduction for voiceless consonants. Stroboscopic recordings using both rigid and flexible endoscopes are demonstrated. Applications are discussed, and the usefulness of simultaneously recording transillumination with other signals is exemplified. [Work supported by NIH.]