One of the major limitations of the fiberoptic endoscopic evaluation of swallowing (FEES) is related to the challenging application of temporal measures. Among them, Whiteout (WO) is due to pharyngeal and tongue base contraction and might be used as an estimation of the pharyngeal phase duration. The aims of this study were to evaluate the inter- and intrarater reliability of WO duration and to appraise the effects of age, sex, volume, and texture of the boluses on this temporal measurement. A total of 30 healthy volunteers were recruited. According to their age, the subjects were grouped into three different age groups. Each of them underwent FEES examination with different textures (liquid, semisolid, and solid) and volumes. FEES examinations were video recorded, processed with the software Daisy Viewer 2.0, which allowed the acquisition of 25 frames per second (s) and analyzed by three different raters in order to collect data on WO duration. A total of 863 swallowing acts were video recorded. Intra- and interrater reliability of WO duration were excellent. Both volume and bolus's texture significantly affected WO duration. In particular, WO duration was significantly shorter for the liquid texture than for the semisolid and solids ones. In addition, male subjects scored significantly higher values of WO duration. Finally, WO duration was significantly higher in seniors. WO duration seems to be a reliable temporal measure during FEES examination. WO duration seems to be affected by several factors such as age, sex, volume, and consistency.
Keywords: Deglutition; Deglutition disorders; FEES; Whiteout.