High-Resolution Manometry as a Tool for Biofeedback in Vertical Laryngeal Positioning

Background. Low vertical larynx results in reduced musculoskeletal tension and easier vocal fold vibration what is critical not only for professional voice users but also for patients with dysphonia. High-resolution manometry (HRM) provides real time upper esophageal sphincter positioning as a surrogate for laryngeal location and it may be a tool for laryngeal excursion biofeedback. This study aims to evaluate HRM as a biofeedback instrument to control vertical laryngeal position. Methods. Ten (50% males, mean age 28 years) professional singers were asked to raise and descent their larynx using any strategy with HRM transnasal catheter in place. The tasks were repeated after the computer screen was positioned at the visual field of the participant that was instructed on how to self-evaluate laryngeal positioning based on the upper esophageal sphincter color plot and the variations with real time images. Results. Median downward laryngeal excursion was 2.0 cm without biofeedback and 3.1 cm after biofeedback (P = 0.03). Median upward laryngeal excursion was 0.2 cm without biofeedback and 0.5 cm after biofeedback (P = 0.4). Conclusions. Singers can improve laryngeal vertical movements, especially the lowering of the larynx, when biofeedback is provided. HRM biofeedback allows singers to visualize the larynx position while singing, facilitating real-time vocal tract position modification and may serve as an efficient tool for singing training.