The effects of endoscope placement in the hypopharynx on swallowing-related measures in healthy adults

Purpose The purpose of this study was to determine whether transnasal passage of a flexible endoscope results in changes in salivary flow rate (SFR), spontaneous swallow frequency (SSF), and masticatory efficiency (ME) in healthy adults. Methods Data were collected from 15 healthy adults, 20–63 years of age. SFR and SSF were measured at baseline, after endoscope insertion, and after endoscope removal. The Test of Masticating and Swallowing Solids was administered at baseline and while the endoscope was in the hypopharynx. A repeated measures ANOVA was used to determine the effect of endoscope insertion on SFR and SSF. A paired samples t-test was used to determine the effect of endoscope insertion on total mastication time and number of masticatory cycles required with a cracker bolus. Statistical significance was set at α = 0.05. Results SFR was found to be significantly increased during endoscope placement in the hypopharynx ( M = 0.471 g/min, SD = 0.175, p = 0.002) as well as following endoscope removal ( M = 0.481 g/min, SD = 0.231, p = 0.004), as compared to baseline ( M = 0.310 g/min, SD = 0.130). Total mastication time and number of masticatory cycles required with a cracker bolus were significantly decreased when the endoscope was present in the hypopharynx, as compared to baseline t (14) = 3.054, p = 0.009; t (14) = 3.250, p = 0.006, respectively. Conclusions Visualization of swallowing during FEES is an important method for objectively evaluating several anatomical and functional parameters of the pharynx and larynx. Insertion of the endoscope into the hypopharynx during FEES may stimulate salivary secretion and improve ME, which could influence interpretation of FEES and resulting clinical recommendations.