Normal limit of the electrogustometry test.

Abstract

Electrical taste thresholds from the right and left anterior parts of the tongue were obtained from 249 normal subjects. Absolute differences between right and left became more variable as the threshold level increased, whereas the variability of relative differences remained more or less constant. The relative difference between right and left electrical taste thresholds was therefore chosen as the measurement of choice for clinical use. It was also found that smoking significantly increased electrogustometry (EGM) test variability, more so in men than in women. Therefore, separate EGM normal limits were defined as follows: nonsmokers, 18%; female smokers, 24%; male smokers, 37%. If the side of the lesion can be predicted, normal limits may be reduced to 15%, 20%, and 32%, respectively. An incidental finding of this study was a correlation between sudden deafness and other “idiopathic,” possibly retrocochlear, lesions and chorda tympani nerve deficits.