2004 Volume 8 Issue 1 Pages 17-25
Objectives：This study observed the normal pharyngeal swallow in terms of viewing of whiteout，movement of the epiglottis and arytenoids closure，and examined the influence of chewing by using videoendoscopy (VE)．
Subjects and Methods： Seven healthy volunteers participated in this study．The tip of the endoscope was placed at two positions， high position (HIGH) and low position (LOW)，and we monitored dry swallow，command swallow of 5 ml of 50％ liquid barium as well as swallow with chewing，and eating of 8 g of corned beef．Subjects were instructed to carry out each of the swallows 3 times．We observed whiteout，movement of the epiglottis and arytenoids closure． The total numbers of trials were 168 swallows； 4 swallows were deleted technically．
Results： We observed movement of the epiglottis and arytenoids closure before and after whiteout from about 70％ to 90％，although we had to select the tip position (HIGH or LOW)．HIGH was suitable for observing the soft palate and return of the epiglottis．LOW was suitable for indicating the start of movement of the epiglottis and of the arytenoids closure．The manner of observation of movement of the epiglottis was different among the subjects． Chewing did not influence the viewing of the epiglottis movement before whiteout． In the swallow with chewing， there were many trials in which arytenoids had not closed before the start of movement of the epiglottis．
Discussion： VE showed viewing of movement of the epiglottis and arytenoids closure by changing the tip position．The manner of observation of movement of the epiglottis varied among individuals． This suggests that the timings of the movement of epiglottis and soft palate are different in each subject． Chewing did not influence the viewing of swallowing events and showed the delay of arytenoids closure． This suggests that VE will be useful for swallowing research including swallow with chewing， and that a synchronized study with videofluorography might reveal new information about swallowing mechanisms．
