Part I of this report on Laryngeal Vibrations, which was published recently in this journal,3 presented detailed measurements of the glottic wave for the normal vibratory cycle. For this study, a series of normal subjects were photographed with an ultrahigh-speed Fastax camera during controlled episodes of phonation, and these films were subjected to frame-by-frame analysis. selected pictures from typical scenes were enlarged for accurate measurements, and a number of interesting new observations regarding the normal vibratory cycle were recorded. The published data include quantitative information regarding the influence of intensity, pitch, and register on the vibratory pattern.
The results were transcribed graphically in norm measures as indicated on Figure 1. The terms "open quotient" and "speed
quotient" were employed to describe the relationship between the different phases of the vocal cord movements in each cycle. For a review of the pertinent literature, and for additional details regarding the technique,
TIMCKE R, LEDEN HV, MOORE P. Laryngeal Vibrations: Measurements of the Glottic Wave: Part II—physiologic Variations. AMA Arch Otolaryngol. 1959;69(4):438–444. doi:10.1001/archotol.1959.00730030448011
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