Mucosal Wave: A Normophonic Study Across Visualization Techniques

Visualization of vocal fold vibration is essential for accurate diagnoses and optimal treatment of persons with voice disorders. Recently, scientific and anecdotal reports have evidenced an increased amount of variation in the diagnostically relevant features of extent and symmetry of mucosal wave magnitude in normophonic speakers. The objectives of this study were to preliminarily ascertain the variation in mucosal wave magnitude and symmetry for normophonic speakers as assessed via standard and novel techniques, and compare findings across modal and pressed phonations. A correlational design with a multiple baseline across visualization methods approach was used. Mucosal wave presence, magnitude, and symmetry from 52 normophonic speakers were judged via stroboscopy, high-speed videoendoscopy (HSV) playback, mucosal wave playback, and mucosal wave kymography playback. Results demonstrate a prevalence of atypical magnitude and symmetry of mucosal wave during modal and pressed phonations by normophonic persons, differences across techniques, and a relationship between judgments and habitual fundamental frequency. Given the prevalence of mucosal wave magnitude and symmetry variations in the normophonic population, overdiagnosis may be possible without caution. The various visualization techniques provided unique information suggesting that it may be beneficial to use both full view and kymographic visualization techniques in combination. A major restriction of the current commercial HSV systems is the frame rate, typically limited to 2000 frames per second, which appears insufficient for most female habitual phonations.