PURPOSE: The purpose of this article is to clear up misconceptions that have propagated in the clinical voice literature that inappropriately cite Talbot's law (1834) and the theory of persistence of vision as the scientific principles that underlie laryngeal stroboscopy. METHOD: After initial research into Talbot's (1834) original studies, it became clear that his experiments were not designed to explain why stroboscopy works. Subsequently, a comprehensive literature search was conducted for the purpose of investigating the general principles of stroboscopic imaging from primary sources. RESULTS: Talbot made no reference to stroboscopy in designing his experiments, and the notion of persistence of vision is not applicable to stroboscopic motion. Instead, two visual phenomena play critical roles: (a) the flicker-free perception of light and (b) the perception of apparent motion. In addition, the integration of stroboscopy with video-based technology in today's voice clinic requires additional complexities to include synchronization with camera frame rates. CONCLUSIONS: References to Talbot's law and the persistence of vision are not relevant to the generation of stroboscopic images. The critical visual phenomena are the flicker-free perception of light intensity and the perception of apparent motion from sampled images. A complete understanding of how laryngeal stroboscopy works will aid in better interpreting clinical findings during voice assessment.
Objectives: Although near-normal conversational voices can be achieved with the phonosurgical management of earlyglottic cancer, there are still acoustic and aerodynamic deficits in vocal function that must be better understood to helpfurther optimize phonosurgical interventions. Stroboscopic assessment is inadequate for this purpose.Methods: A newly developed color high-speed videoendoscopy (HSV) system that included time-synchronized recordingsof the acoustic signal was used to perform a detailed examination of voice production mechanisms in 14 subjects.Digital image processing techniques were used to quantify glottal phonatory function and to delineate relationships betweenvocal fold vibratory properties and acoustic perturbation measures.Results: The results for multiple measurements of vibratory asymmetry showed that 31% to 62% of subjects displayedhigher-than-normal average values, whereas the mean values for glottal closure duration (open quotient) and periodicityof vibration fell within normal limits. The average HSV-based measures did not correlate significantly with the acousticperturbation measures, but moderate correlations were exhibited between the acoustic measures and the SDs of the HSVbasedparameters.Conclusions: The use of simultaneous, time-synchronized HSV and acoustic recordings can provide new insights intopostoperative voice production mechanisms that cannot be obtained with stroboscopic assessment.