[Evaluation of gustatory threshold changes in healthy subjects]

Changes in gustatory thresholds were examined in 30 healthy volunteers by conducting electrogustometry and the filter-paper disc method, three times with a 4 week or longer interval. Gustatory thresholds, obtained from either method, notably decreased in the second and the third examination in many subjects. In chronological observations by using the electrogustometry, changes of 6 dB or less in the chorda tympani nerve area or 8 to 10 dB less in the glossopharyngeal nerve area were considered to be not significant. In the filter-paper disc method, the threshold changes with one concentration grade of test solution were observed at high frequency, while the threshold changes with two concentration grades or more were very rare, however all changes were significant. In the filter-paper disc method, changes of the gustatory threshold in one or two kinds of tastes were relatively frequently observed. However, the gustatory thresholds of three or four kinds of tastes rarely changed simultaneously even by one concentration grade of those taste solutions. If such multiple changes of the taste thresholds occur, even when each taste threshold changed only by one concentration grade, it was as a significant change.